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Rosa Puertollano - One of the best experts on this subject based on the ideXlab platform.
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the transcription factors TFE3 and tfeb amplify p53 dependent transcriptional programs in response to dna damage
eLife, 2018Co-Authors: Owen A. Brady, Eutteum Jeong, Jose A Martina, Ilker Tunc, Mehdi Pirooznia, Rosa PuertollanoAbstract:: The transcription factors TFE3 and TFEB cooperate to regulate autophagy induction and lysosome biogenesis in response to starvation. Here we demonstrate that DNA damage activates TFE3 and TFEB in a p53 and mTORC1 dependent manner. RNA-Seq analysis of TFEB/TFE3 double-knockout cells exposed to etoposide reveals a profound dysregulation of the DNA damage response, including upstream regulators and downstream p53 targets. TFE3 and TFEB contribute to sustain p53-dependent response by stabilizing p53 protein levels. In TFEB/TFE3 DKOs, p53 half-life is significantly decreased due to elevated Mdm2 levels. Transcriptional profiles of genes involved in lysosome membrane permeabilization and cell death pathways are dysregulated in TFEB/TFE3-depleted cells. Consequently, prolonged DNA damage results in impaired LMP and apoptosis induction. Finally, expression of multiple genes implicated in cell cycle control is altered in TFEB/TFE3 DKOs, revealing a previously unrecognized role of TFEB and TFE3 in the regulation of cell cycle checkpoints in response to stress.
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the transcription factors tfeb and TFE3 link the flcn ampk signaling axis to innate immune response and pathogen resistance
bioRxiv, 2018Co-Authors: Leeanna Elhoujeiri, Jose A Martina, Elite Possik, Tarika Vijayaraghavan, Mathieu Paquette, Jalal M Kazan, Eric H, Paola Blanchette, Russell G Jones, Rosa PuertollanoAbstract:TFEB and TFE3 are transcriptional regulators of the innate immune response, but the mechanisms regulating their activation upon pathogen infection are poorly elucidated. Using C. elegans and mammalian models, we report that the master metabolic modulator 5'-AMP-activated protein kinase (AMPK) and its negative regulator Folliculin (FLCN) act upstream of TFEB/TFE3 in the innate immune response, independently of the mTORC1 signaling pathway. In nematodes, loss of FLCN or overexpression of AMPK conferred pathogen resistance via activation of TFEB/TFE3-dependent antimicrobial genes, while ablation of total AMPK activity abolished this phenotype. Similarly, in mammalian cells, loss of FLCN or pharmacological activation of AMPK induced TFEB/TFE3-dependent pro-inflammatory cytokine expression. Importantly, a rapid reduction in cellular ATP levels in murine macrophages was observed upon lipopolysaccharide (LPS) treatment accompanied by an acute AMPK activation and TFEB nuclear localization. These results uncover an ancient, highly conserved and pharmacologically actionable mechanism coupling energy status with innate immunity.
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protein phosphatase 2a stimulates activation of tfeb and TFE3 transcription factors in response to oxidative stress
Journal of Biological Chemistry, 2018Co-Authors: Jose A Martina, Rosa PuertollanoAbstract:: Adaptations and responses to stress conditions are fundamental processes that all cells must accomplish to maintain or restore cellular homeostasis. Cells have a plethora of response pathways to mitigate the effect of different environmental stressors. The transcriptional regulators transcription factor EB (TFEB) and transcription factor binding to IGHM enhancer 3 (TFE3) play a key role in the control of these stress pathways. Therefore, understanding their regulation under different stress conditions is of great interest. Here, using a range of human and murine cells, we show that TFEB and TFE3 are activated upon induction of acute oxidative stress by sodium arsenite via an mTOR complex 1 (mTORC1)-independent process. We found that the mechanism of arsenite-stimulated TFEB and TFE3 activation instead involves protein phosphatase 2A (PP2A)-mediated dephosphorylation at Ser-211 and Ser-321, respectively. Depletion of either the catalytic (PPP2CA+B) or regulatory (PPP2R2A/B55α) subunits of PP2A, as well as PP2A inactivation with the specific inhibitor okadaic acid, abolished TFEB and TFE3 activation in response to sodium arsenite. Conversely, PP2A activation by ceramide or the sphingosine-like compound FTY720 was sufficient to induce TFE3 nuclear translocation. MS analysis revealed that PP2A dephosphorylates TFEB at several residues, including Ser-109, Ser-114, Ser-122, and Ser-211, thus facilitating TFEB activation. Overall, this work identifies a critical mechanism that activates TFEB and TFE3 without turning off mTORC1 activity. We propose that this mechanism may enable some cell types such as immune or cancer cells that require simultaneous TFEB/TFE3 and mTORC1 signaling to survive and achieve robust cell growth in stressful environments.
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the complex relationship between tfeb transcription factor phosphorylation and subcellular localization
The EMBO Journal, 2018Co-Authors: Rosa Puertollano, James Brugarolas, Shawn M Ferguson, Andrea BallabioAbstract:Abstract The MiT‐TFE family of basic helix‐loop‐helix leucine‐zipper transcription factors includes four members: TFEB, TFE3, TFEC, and MITF. Originally described as oncogenes, these factors play a major role as regulators of lysosome biogenesis, cellular energy homeostasis, and autophagy. An important mechanism by which these transcription factors are regulated involves their shuttling between the surface of lysosomes, the cytoplasm, and the nucleus. Such dynamic changes in subcellular localization occur in response to nutrient fluctuations and various forms of cell stress and are mediated by changes in the phosphorylation of multiple conserved amino acids. Major kinases responsible for MiT‐TFE protein phosphorylation include mTOR, ERK, GSK3, and AKT. In addition, calcineurin de‐phosphorylates MiT‐TFE proteins in response to lysosomal calcium release. Thus, through changes in the phosphorylation state of MiT‐TFE proteins, lysosome function is coordinated with the cellular metabolic state and cellular demands. This review summarizes the evidence supporting MiT‐TFE regulation by phosphorylation at multiple key sites. Elucidation of such regulatory mechanisms is of fundamental importance to understand how these transcription factors contribute to both health and disease.
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lysosome enlargement during inhibition of the lipid kinase pikfyve proceeds through lysosome coalescence
Journal of Cell Science, 2018Co-Authors: Christopher H Choy, Roya M. Dayam, Rosa Puertollano, Golam Saffi, Matthew A Gray, Callen T Wallace, Zhenyi A Ou, Guy M Lenk, Simon C Watkins, Roberto J. BotelhoAbstract:Lysosomes receive and degrade cargo from endocytosis, phagocytosis and autophagy. They also play an important role in sensing and instructing cells on their metabolic state. The lipid kinase PIKfyve generates phosphatidylinositol-3,5-bisphosphate to modulate lysosome function. PIKfyve inhibition leads to impaired degradative capacity, ion dysregulation, abated autophagic flux, and a massive enlargement of lysosomes. Collectively, this leads to various physiological defects including embryonic lethality, neurodegeneration and overt inflammation. While being the most dramatic phenotype, the reasons for lysosome enlargement remain unclear. Here, we examined whether biosynthesis and/or fusion-fission dynamics contribute to swelling. First, we show that PIKfyve inhibition activates TFEB, TFE3 and MITF enhancing lysosome gene expression. However, this did not augment lysosomal protein levels during acute PIKfyve inhibition and deletion of TFEB and/or related proteins did not impair lysosome swelling. Instead, PIKfyve inhibition led to fewer but enlarged lysosomes, suggesting that an imbalance favouring lysosome fusion over fission causes lysosome enlargement. Indeed, conditions that abated fusion curtailed lysosome swelling in PIKfyve-inhibited cells.
Jose A Martina - One of the best experts on this subject based on the ideXlab platform.
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the transcription factors TFE3 and tfeb amplify p53 dependent transcriptional programs in response to dna damage
eLife, 2018Co-Authors: Owen A. Brady, Eutteum Jeong, Jose A Martina, Ilker Tunc, Mehdi Pirooznia, Rosa PuertollanoAbstract:: The transcription factors TFE3 and TFEB cooperate to regulate autophagy induction and lysosome biogenesis in response to starvation. Here we demonstrate that DNA damage activates TFE3 and TFEB in a p53 and mTORC1 dependent manner. RNA-Seq analysis of TFEB/TFE3 double-knockout cells exposed to etoposide reveals a profound dysregulation of the DNA damage response, including upstream regulators and downstream p53 targets. TFE3 and TFEB contribute to sustain p53-dependent response by stabilizing p53 protein levels. In TFEB/TFE3 DKOs, p53 half-life is significantly decreased due to elevated Mdm2 levels. Transcriptional profiles of genes involved in lysosome membrane permeabilization and cell death pathways are dysregulated in TFEB/TFE3-depleted cells. Consequently, prolonged DNA damage results in impaired LMP and apoptosis induction. Finally, expression of multiple genes implicated in cell cycle control is altered in TFEB/TFE3 DKOs, revealing a previously unrecognized role of TFEB and TFE3 in the regulation of cell cycle checkpoints in response to stress.
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the transcription factors tfeb and TFE3 link the flcn ampk signaling axis to innate immune response and pathogen resistance
bioRxiv, 2018Co-Authors: Leeanna Elhoujeiri, Jose A Martina, Elite Possik, Tarika Vijayaraghavan, Mathieu Paquette, Jalal M Kazan, Eric H, Paola Blanchette, Russell G Jones, Rosa PuertollanoAbstract:TFEB and TFE3 are transcriptional regulators of the innate immune response, but the mechanisms regulating their activation upon pathogen infection are poorly elucidated. Using C. elegans and mammalian models, we report that the master metabolic modulator 5'-AMP-activated protein kinase (AMPK) and its negative regulator Folliculin (FLCN) act upstream of TFEB/TFE3 in the innate immune response, independently of the mTORC1 signaling pathway. In nematodes, loss of FLCN or overexpression of AMPK conferred pathogen resistance via activation of TFEB/TFE3-dependent antimicrobial genes, while ablation of total AMPK activity abolished this phenotype. Similarly, in mammalian cells, loss of FLCN or pharmacological activation of AMPK induced TFEB/TFE3-dependent pro-inflammatory cytokine expression. Importantly, a rapid reduction in cellular ATP levels in murine macrophages was observed upon lipopolysaccharide (LPS) treatment accompanied by an acute AMPK activation and TFEB nuclear localization. These results uncover an ancient, highly conserved and pharmacologically actionable mechanism coupling energy status with innate immunity.
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protein phosphatase 2a stimulates activation of tfeb and TFE3 transcription factors in response to oxidative stress
Journal of Biological Chemistry, 2018Co-Authors: Jose A Martina, Rosa PuertollanoAbstract:: Adaptations and responses to stress conditions are fundamental processes that all cells must accomplish to maintain or restore cellular homeostasis. Cells have a plethora of response pathways to mitigate the effect of different environmental stressors. The transcriptional regulators transcription factor EB (TFEB) and transcription factor binding to IGHM enhancer 3 (TFE3) play a key role in the control of these stress pathways. Therefore, understanding their regulation under different stress conditions is of great interest. Here, using a range of human and murine cells, we show that TFEB and TFE3 are activated upon induction of acute oxidative stress by sodium arsenite via an mTOR complex 1 (mTORC1)-independent process. We found that the mechanism of arsenite-stimulated TFEB and TFE3 activation instead involves protein phosphatase 2A (PP2A)-mediated dephosphorylation at Ser-211 and Ser-321, respectively. Depletion of either the catalytic (PPP2CA+B) or regulatory (PPP2R2A/B55α) subunits of PP2A, as well as PP2A inactivation with the specific inhibitor okadaic acid, abolished TFEB and TFE3 activation in response to sodium arsenite. Conversely, PP2A activation by ceramide or the sphingosine-like compound FTY720 was sufficient to induce TFE3 nuclear translocation. MS analysis revealed that PP2A dephosphorylates TFEB at several residues, including Ser-109, Ser-114, Ser-122, and Ser-211, thus facilitating TFEB activation. Overall, this work identifies a critical mechanism that activates TFEB and TFE3 without turning off mTORC1 activity. We propose that this mechanism may enable some cell types such as immune or cancer cells that require simultaneous TFEB/TFE3 and mTORC1 signaling to survive and achieve robust cell growth in stressful environments.
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emerging roles for tfeb in the immune response and inflammation
Autophagy, 2018Co-Authors: Owen A. Brady, Jose A Martina, Rosa PuertollanoAbstract:ABSTRACTInflammation is a central feature of an effective immune response, which functions to eliminate pathogens and other foreign material, and promote recovery; however, dysregulation of the inflammatory response is associated with a wide variety of disease states. The autophagy-lysosome pathway is one of 2 major degradative pathways used by the cell and serves to eliminate long-lived and dysfunctional proteins and organelles to maintain homeostasis. Mounting evidence implicates the autophagy-lysosome pathway as a key player in regulating the inflammatory response; hence many inflammatory diseases may fundamentally be diseases of autophagy-lysosome pathway dysfunction. The recent identification of TFEB and TFE3 as master regulators of macroautophagy/autophagy and lysosome function raises the possibility that these transcription factors may be of central importance in linking autophagy and lysosome dysfunction with inflammatory disorders. Here, we review the current state of knowledge linking TFEB and T...
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tfeb regulates lysosomal positioning by modulating tmem55b expression and jip4 recruitment to lysosomes
Nature Communications, 2017Co-Authors: Rose Willett, Jose A Martina, James P Zewe, Rachel C Wills, Gerald R.v. Hammond, Rosa PuertollanoAbstract:Lysosomal distribution is linked to the role of lysosomes in many cellular functions, including autophagosome degradation, cholesterol homeostasis, antigen presentation, and cell invasion. Alterations in lysosomal positioning contribute to different human pathologies, such as cancer, neurodegeneration, and lysosomal storage diseases. Here we report the identification of a novel mechanism of lysosomal trafficking regulation. We found that the lysosomal transmembrane protein TMEM55B recruits JIP4 to the lysosomal surface, inducing dynein-dependent transport of lysosomes toward the microtubules minus-end. TMEM55B overexpression causes lysosomes to collapse into the cell center, whereas depletion of either TMEM55B or JIP4 results in dispersion toward the cell periphery. TMEM55B levels are transcriptionally upregulated following TFEB and TFE3 activation by starvation or cholesterol-induced lysosomal stress. TMEM55B or JIP4 depletion abolishes starvation-induced retrograde lysosomal transport and prevents autophagosome–lysosome fusion. Overall our data suggest that the TFEB/TMEM55B/JIP4 pathway coordinates lysosome movement in response to a variety of stress conditions. Lysosomal distribution is linked to the role of lysosomes in many cellular functions. Here the authors show that the lysosomal protein TMEM55B is regulated by TFEB and recruits JIP4 to the lysosomal surface inducing dynein-dependent transport of lysosomes toward the cell center in response to stress conditions.
David E. Fisher - One of the best experts on this subject based on the ideXlab platform.
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TFE3 and tfeb transcriptionally regulate peroxisome proliferator activated receptor γ2 expression in adipocytes and mediate adiponectin and glucose levels in mice
Molecular and Cellular Biology, 2017Co-Authors: Nunciada Salma, Akinori Kawakami, Suprabha P Devi, Mehdi Khaled, Jose M Cacicedo, Jun S. Song, David E. FisherAbstract:: Members of the MiT transcription factor family are pivotal regulators of several lineage-selective differentiation programs. We show that two of these, Tfeb and TFE3, control the regulator of adipogenesis, peroxisome proliferator-activated receptor γ2 (Pparγ2). Knockdown of Tfeb or TFE3 expression during in vitro adipogenesis causes dramatic downregulation of Pparγ2 expression as well as adipogenesis. Additionally, we found that these factors regulate Pparγ2 in mature adipocytes. Next, we demonstrated that Tfeb and TFE3 act directly by binding to consensus E-boxes within the Pparγ transcriptional regulatory region. This transcriptional control also exists in vivo, as we discovered that wild-type mice in the fed state increased their expression of TFE3, Tf3b, and Pparγ in white adipose tissue. Furthermore, TFE3 knockout (TFE3KO) mice in the fed state failed to upregulate Pparγ and the adiponectin gene, a Pparγ-dependent gene, confirming the in vivo role for TFE3. Lastly, we found that blood glucose is elevated and serum adiponectin levels are suppressed in the TFE3KO mice, indicating that the TFE3/Tfeb/Pparγ2 axis may contribute to whole-body energy balance. Thus, we offer new insights into the upstream regulation of Pparγ by TFE3/Tf3b and propose that targeting these transcription factors may offer opportunities to complement existing approaches for the treatment of diseases that have dysregulated energy metabolism.
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TFE3 and Tfeb transcriptionally regulate Pparγ2 expression in adipocytes and mediate adiponectin and glucose levels in mice.
Molecular and Cellular Biology, 2017Co-Authors: Nunciada Salma, Akinori Kawakami, Suprabha P Devi, Mehdi Khaled, Jose M Cacicedo, Jun S. Song, David E. FisherAbstract:Abstract Members of the MiT transcription factor family are pivotal regulators of several lineage-selective differentiation programs. We show that two of these, Tfeb and TFE3, control the regulator of adipogenesis, Pparγ2. Knockdown of Tfeb or TFE3 expression during in vitro adipogenesis causes dramatic downregulation of Pparγ2 expression as well as adipogenesis. Additionally, we found that these factors regulate Pparγ2 in mature adipocytes. Next, we demonstrated that Tfeb and TFE3 act directly by binding to consensus E-boxes within the Pparγ transcriptional regulatory region. This transcriptional control also exists in vivo as we discovered that wildtype mice in the fed state increased their expression of TFE3, Tf3b, and Pparγ in white adipose tissue. Furthermore, TFE3KO mice in the fed state failed to upregulate Pparγ and adiponectin, a Pparγ dependent gene confirming the in vivo role for TFE3. Lastly, we found that blood glucose is elevated and adiponectin serum levels suppressed in the TFE3KO mice indicating that the TFE3/Tfeb/Pparγ2 axis may contribute to whole body energy balance. Thus, we offer new insights into the upstream regulation of Pparγ by TFE3/Tf3b and propose that targeting these transcription factors may offer opportunities to complement existing approaches for the treatment of diseases that have dysregulated energy metabolism.
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transcription factor TFE3 directly regulates pgc 1alpha in muscle
Journal of Cellular Physiology, 2015Co-Authors: Nunciada Salma, Jun S. Song, Zoltan Arany, David E. FisherAbstract:The microphthalmia (MiT) family of basic helix-loop-helix leucine zipper transcription factors includes Mitf, TFE3, Tfeb, and Tfec family members. These factors regulate gene expression by binding in a homo- or hetero-dimeric manner to a specific consensus sequence called E-boxes that resides in promoter regions of target genes (Beckmann and Kadesch, 1991; Zhao et al., 1993; Steingrimsson et al., 2004). A significant number of biological and pathological processes are regulated by MiT factors. Recently MiT factors have been recognized as major players controlling the expression of key metabolic genes. TFE3 mediates metabolism through the regulation of genes that participate directly in the insulin-signaling pathway (Nakagawa et al., 2006), through the regulation of lipolysis in adipose tissue (Fujimoto et al., 2013), and through the regulation of glucose metabolism in skeletal muscle (Iwasaki et al., 2012). Mitf directly regulates the expression of the master coactivator PGC-1alpha in melanomas (Haq et al., 2013; Vazquez et al., 2013), while Tfeb participates in lipid metabolism through direct regulation of Pgc-1alpha and Ppar-alpha complex in liver (Settembre et al., 2013) and functions as a key transcriptional regulator of autophagy (Settembre et al., 2011). The Pgc1 family of coactivators has three members: Pgc-1alpha, Pgc-1beta, and PRC. Pgc-1alpha is a coregulator of cell metabolism that induces mitochondrial biogenesis, mitochondrial remodeling, respiration, gluconeogenesis and glucose transport, fatty acid oxidation, peroxisomal remodeling, and detoxification of reactive oxygen species (ROS) (Puigserver, 2005; Handschin and Spiegelman, 2006; Austin and St-Pierre, 2012). Pgc-1alpha and Pgc-1beta are expressed in mitochondrial rich tissues such as skeletal muscle, and they overlap functionally (St-Pierre et al., 2003; Handschin and Spiegelman, 2006; Rowe et al., 2010). Many physiological stimuli that require a demanding metabolic response induce expression of Pgc-1alpha including: cold, exercise, oxidative stress, and fasting (Ventura-Clapier et al., 2008). During cold shock, Pgc-1alpha stimulates the expression of uncoupling protein 1 (Ucp1) in brown adipose tissue (BAT) and, consequently, adaptive thermogenesis (Puigserver et al., 1998; Lin et al., 2004); in skeletal muscle Pgc-1alpha stimulates glucose uptake and is involved in the expression of muscle fiber type I and IIa (Michael et al., 2001a; Lin et al., 2002b). Endurance training has been shown to activate Pgc-1alpha reinforcing mitochondrial biogenesis, fatty acid oxidation and angiogenesis (Arany, 2008). Following fasting the expression of Pgc-1alpha is elevated in the liver, thus mediating metabolic programs through the coactivation of hepatic transcription factors (Lin et al., 2005). Based on previous investigations that show that Mitf and Tfeb regulate Pgc-1alpha expression by directly binding to the Pgc-1alpha promoter (Lin et al., 2002b; Settembre et al., 2011, 2013; Strub et al., 2011; Haq et al., 2013; Vazquez et al., 2013), we predicted that TFE3 might also function as an important regulator of Pgc-1alpha expression. We demonstrate here that overexpression or downregulation of TFE3 in primary differentiated myoblasts and in differentiated C2C12 cells resulted in a significant increase or reduction in levels of Pgc-1alpha, respectively. The mouse promoter region of the Pgc-1alpha gene was evaluated, and three E-boxes were found. We confirmed by ChIP and luciferase assays that TFE3 transactivates two of the three consensus sequences. Due to the role of Pgc-1alpha in modulating energy metabolism, tuning its expression pharmacologically has been under study for the treatment of metabolic maladies. Specifically targeting transcription factors like TFE3 involved in the regulation of Pgc-1alpha can effectively modulate Pgc-1alpha expression at physiological levels. MiT factors are interesting targets since recently they have been used for the treatment of human neurological and lysosomal diseases and in cancer (Kauffman et al., 2014; Martina et al., 2014).
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cloning of an alpha tfeb fusion in renal tumors harboring the t 6 11 p21 q13 chromosome translocation
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Ian J. Davis, Patricia Valencia, Antonio R Perezatayde, Jonathan A Fletcher, Marc Ladanyi, Jason D Arroyo, Gabriela Motyckova, Pedram Argani, Sara O Vargas, David E. FisherAbstract:MITF, TFE3, TFEB, and TFEC comprise a transcription factor family (MiT) that regulates key developmental pathways in several cell lineages. Like MYC, MiT members are basic helix-loop-helix-leucine zipper transcription factors. MiT members share virtually perfect homology in their DNA binding domains and bind a common DNA motif. Translocations of TFE3 occur in specific subsets of human renal cell carcinomas and in alveolar soft part sarcomas. Although multiple translocation partners are fused to TFE3, each translocation product retains TFE3's basic helix–loop–helix leucine zipper. We have identified the genes fused by the chromosomal translocation t(6;11)(p21.1;q13), characteristic of another subset of renal neoplasms. In two primary tumors we found that Alpha, an intronless gene, rearranges with the first intron of TFEB, just upstream of TFEB's initiation ATG, preserving the entire TFEB coding sequence. Fluorescence in situ hybridization confirmed the involvement of both TFEB and Alpha in this translocation. Although the Alpha promoter drives expression of this fusion gene, the Alpha gene does not contribute to the ORF. Whereas TFE3 is typically fused to partner proteins in subsets of renal tumors, we found that wild-type, unfused TFE3 stimulates clonogenic growth in a cell-based assay, suggesting that dysregulated expression, rather than altered function of TFEB or TFE3 fusions, may confer neoplastic properties, a mechanism reminiscent of MYC activation by promoter substitution in Burkitt's lymphoma. Alpha-TFEB is thus identified as a fusion gene in a subset of pediatric renal neoplasms.
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linking osteopetrosis and pycnodysostosis regulation of cathepsin k expression by the microphthalmia transcription factor family
Proceedings of the National Academy of Sciences of the United States of America, 2001Co-Authors: Gabriela Motyckova, Katherine N Weilbaecher, Martin A Horstmann, D J Rieman, Daniel Z Fisher, David E. FisherAbstract:Various genetic conditions produce dysfunctional osteoclasts resulting in osteopetrosis or osteosclerosis. These include human pycnodysostosis, an autosomal recessive syndrome caused by cathepsin K mutation, cathepsin K-deficient mice, and mitf mutant rodent strains. Cathepsin K is a highly expressed cysteine protease in osteoclasts that plays an essential role in the degradation of protein components of bone matrix. Cathepsin K also is expressed in a significant fraction of human breast cancers where it could contribute to tumor invasiveness. Mitf is a member of a helix–loop–helix transcription factor subfamily, which contains the potential dimerization partners TFE3, TFEB, and TFEC. In mice, dominant negative, but not recessive, mutations of mitf, produce osteopetrosis, suggesting a functional requirement for other family members. Mitf also has been found—and TFE3 has been suggested—to modulate age-dependent changes in osteoclast function. This study identifies cathepsin K as a transcriptional target of Mitf and TFE3 via three consensus elements in the cathepsin K promoter. Additionally, cathepsin K mRNA and protein were found to be deficient in mitf mutant osteoclasts, and overexpression of wild-type Mitf dramatically up-regulated expression of endogenous cathepsin K in cultured human osteoclasts. Cathepsin K promoter activity was disrupted by dominant negative, but not recessive, mouse alleles of mitf in a pattern that closely matches their osteopetrotic phenotypes. This relationship between cathepsin K and the Mitf family helps explain the phenotypic overlap of their corresponding deficiencies in pycnodysostosis and osteopetrosis and identifies likely regulators of cathepsin K expression in bone homeostasis and human malignancy.
Marc Ladanyi - One of the best experts on this subject based on the ideXlab platform.
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Utilization of a TFE3 break-apart FISH assay in a renal tumor consultation service.
The American journal of surgical pathology, 2013Co-Authors: Whitney M. Green, Laura Morsberger, Kerry Morris, Marc Ladanyi, Peter B Illei, Raluca Yonescu, George J Netto, Jonathan I. Epstein, Mohamad E. Allaf, Constance A GriffinAbstract:Xp11 translocation renal cell carcinomas (RCCs) are characterized by chromosome translocations involving the Xp11.2 breakpoint, resulting in gene fusions involving the TFE3 transcription factor. In archival material, the diagnosis can often be confirmed by TFE3 immunohistochemistry (IHC), but variable fixation (especially prevalent in consultation material) can lead to equivocal results. A TFE3 break-apart fluorescence in situ hybridization (FISH) assay has been developed to detect TFE3 gene rearrangements; however, the utility of this assay in a renal tumor consultation practice has not been examined. We reviewed 95 consecutive renal tumor consultation cases submitted to rule in or rule out Xp11 translocation RCC. Thirty-one cases were positive for TFE3 rearrangements by FISH. Patients ranged from 6 to 67 years of age (mean=30 y; median=28 y). Novel or distinctive morphologic features of these cases included extensive cystic change simulating multilocular cystic RCC (3 cases), sarcomatoid transformation (3 cases), oncocytic areas mimicking oncocytoma (1 case), trabecular architecture mimicking a carcinoid tumor (1 case), colonization of renal pelvic urothelium mimicking urothelial carcinoma in situ (1), and focal desmin and diffuse racemase immunoreactivity (1 case each). Twenty-six of the 31 TFE3 FISH-positive RCCs were unequivocally positive for TFE3 by IHC, but 4 were equivocal, and 1 was negative. Of the 64 cases that were negative by TFE3 FISH, 50 were negative by TFE3 IHC, and 14 were equivocal. Thirty-two of the 64 TFE3 FISH-negative cases could be classified into other accepted RCC subtypes: 23 as clear cell RCC, 5 as papillary RCC, 3 as clear cell papillary RCC, and 1 as chromophobe RCC. The other 32 cases remained unclassified, including 3 cathepsin K-positive RCC that closely resembled Xp11 translocation RCC. In conclusion, TFE3 FISH is highly useful in renal tumor consultation material, often resolving cases with equivocal TFE3 IHC results. Given the difficulty of optimizing TFE3 IHC, TFE3 FISH is for most laboratories the optimal test for establishing the diagnosis of Xp11 translocation RCC.
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molecular confirmation of t 6 11 p21 q12 renal cell carcinoma in archival paraffin embedded material using a break apart tfeb fish assay expands its clinicopathologic spectrum
The American Journal of Surgical Pathology, 2012Co-Authors: Pedram Argani, Laura Morsberger, Kerry Morris, Nilda González, Marc Ladanyi, Peter B Illei, Nathan Smith, Raluca Yonescu, George J Netto, Constance A GriffinAbstract:The past decade has witnessed the characterization of a subset of renal cell carcinomas (RCCs) that have chromosomal translocations resulting in gene fusions involving members of the MiT subfamily of transcription factors. The best known members of this subset are the Xp11 translocation RCCs, which were recognized by the World Health Organization in 2004.1 These neoplasms comprise the majority of pediatric RCCs and a smaller percentage of adult RCCs and classically feature a papillary architecture lined by clear cells with extensive psammomatous calcification.2–8 Xp11 translocation RCCs are characterized by gene fusions involving the TFE3 transcription factor gene that maps to this locus; at least 5 different fusion partners for TFE3 have been identified to date.2,3,5,9,10 A less well-known member of the translocation RCC family is the subset of RCCs characterized by t(6;11)(p21;q12), which results in fusion of the untranslated Alpha (MALAT1) gene on 11q12 to the related TFEB gene on 6p21.11–14 Only 21 genetically confirmed cases of t(6;11) RCCs have been reported.5,11–23 This neoplasm typically demonstrates a distinctive biphasic morphology, comprising larger epithelioid cells and smaller cells clustered around basement membrane material; however, the full spectrum of its morphologic appearances is not known. The t(6;11) RCCs differ from most conventional RCCs in that they consistently express melanocytic immunohistochemical (IHC) markers such as HMB45, Melan A, and the cysteine protease cathepsin K24,25 but are either negative or only focally positive for epithelial markers such as cytokeratins.11,12 On the basis of clinical, pathologic, and genetic similarities between the t(6;11) RCCs and the Xp11 translocation RCCs, we have proposed that these 2 neoplasms be classified together under the broader category of “MiT family translocation RCC.”12 Molecular confirmation of a diagnosis of a translocation RCC is relatively simple if fresh tissue is available for either cytogenetics or reverse transcriptase polymerase chain reaction assay using primers from the genes known to be involved in the gene fusion. However, in many cases, only archival, formalin-fixed, paraffin-embedded material is available. For the Xp11 translocation RCCs and t(6;11) RCCs, IHC for TFE3 and TFEB, respectively, have proven to be useful for confirming the diagnosis in archival material.6,12 This is because both TFE3 fusion proteins and native TFEB are upregulated by promoter substitution by the gene fusions in these 2 RCCs relative to the level of expression of the respective native proteins. However, IHC is highly fixation dependent and has proven to be particularly difficult for TFE3 and TFEB for several reasons. These include the scarcity of genetically confirmed positive controls and the fact that the assays are optimally performed by overnight incubation, which is difficult to automate.26 Recently, break-apart fluorescence in situ hybridization (FISH) assays for TFE3 gene fusions were developed for archival material27–29 and have allowed the expansion of the morphologic spectrum of the Xp11 translocation RCCs.30 A validated FISH assay for molecular confirmation of t(6;11) RCC has not been reported previously. We report herein the development of a break-apart TFEB FISH assay for the diagnosis of t(6;11)(p21;q12) RCCs. We validated the assay on 4 genetically confirmed cases and 76 pertinent negative control cases, confirmed the presence of a TFEB gene rearrangement in a previously reported TFEB IHC-positive case from 46 years ago, and used the assay to report 8 new cases that expanded the clinicopathologic spectrum of t(6;11) RCCs.
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differential expression of cathepsin k in neoplasms harboring TFE3 gene fusions
Modern Pathology, 2011Co-Authors: Guido Martignoni, Diego Segala, Enrico Munari, Georges J. Netto, Matteo Brunelli, Stefano Gobbo, Franco Bonetti, Peter B Illei, P Camparo, Marc LadanyiAbstract:Cathepsin K is a protease whose expression is driven by microphthalmia transcription factor (MITF) in osteoclasts. TFE3 and TFEB are members of the same transcription factor subfamily as MITF and all three have overlapping transcriptional targets. We have shown that all t(6;11) renal cell carcinomas, which harbor an Alpha-TFEB gene fusion, as well as a subset of the Xp11 translocation renal carcinomas, which harbor various TFE3 gene fusions, express cathepsin K, while no other common renal carcinoma does. We have hypothesized that overexpression of TFEB or certain TFE3 fusion proteins function like MITF in these neoplasms, and thus activate cathepsin K expression. However, the expression of cathepsin K in specific genetic subtypes of Xp11 translocation carcinomas, as well as alveolar soft part sarcoma, which harbors the same ASPSCR1-TFE3 gene fusion as some Xp11 translocation carcinomas, has not been addressed. We performed immunohistochemistry for cathepsin K on 14 genetically confirmed t(X;1)(p11;q21) carcinomas, harboring the PRCC-TFE3 gene fusion; eight genetically confirmed t(X;17)(p11;q25) carcinomas, harboring the ASPSCR1-TFE3 gene fusion; and 18 alveolar soft part sarcomas (12 genetically confirmed), harboring the identical ASPSCR1-TFE3 gene fusion. All 18 alveolar soft part sarcomas expressed cathepsin K. In contrast, all eight ASPSCR1-TFE3 carcinomas were completely negative for cathepsin K. However, 12 of 14 PRCC-TFE3 carcinomas expressed cathepsin K. Expression of cathepsin K distinguishes alveolar soft part sarcoma from the ASPSCR1-TFE3 carcinoma, harboring the same gene fusion. The latter can be useful diagnostically, especially when alveolar soft part sarcoma presents in an unusual site (such as bone) or with clear cell morphology, which raises the differential diagnosis of metastatic ASPSCR1-TFE3 renal cell carcinoma. The difference in expression of cathepsin K between the PRCC-TFE3 and ASPSCR1-TFE3 carcinomas, together with the observed clinical differences between these subtypes of Xp11 translocation carcinomas, suggests the possibility of functional differences between these two related fusion proteins.
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a novel cltc TFE3 gene fusion in pediatric renal adenocarcinoma with t x 17 p11 2 q23
Oncogene, 2003Co-Authors: Pedram Argani, Jerome Couturier, Raymonde Bouvier, Jeanchristophe Fournet, Marc LadanyiAbstract:A distinctive subset of renal carcinomas is associated with Xp11.2 translocations and resulting TFE3 gene fusions (PRCC–TFE3, PSF–TFE3, NONO–TFE3, ASPL–TFE3), encoding related aberrant transcription factors. We report the cloning of a novel clathrin heavy-chain gene (CLTC)–TFE3 gene fusion resulting from a t(X;17)(p11.2;q23) in a renal carcinoma arising in a 14-year-old boy. The fusion transcript joined the 5′ exons of CLTC on chromosome band 17q23 to the 3′ exons of TFE3. CLTC encodes a major subunit of clathrin, a multimeric protein on cytoplasmic organelles, and is a known recurrent fusion partner of the ALK tyrosine kinase gene in anaplastic large-cell lymphoma and inflammatory myofibroblastic tumors. The predicted CLTC–TFE3 product retains the nuclear localization and DNA-binding domains of TFE3, but lacks the multimerization domain of CLTC. The present renal tumor demonstrated morphologic and immunohistochemical features of both PRCC–TFE3 and ASPL–TFE3 carcinomas, including strong nuclear immunoreactivity for the TFE3 C-terminal and only minimal expression of epithelial proteins. However, unlike most renal carcinomas, it also focally expressed melanocytic proteins. The present report highlights the promiscuity of certain genes involved in chromosomal translocations. Further analysis of the shared features of CLTC and other TFE3 fusion partners may shed light on the essential biology of TFE3 fusion proteins.
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cloning of an alpha tfeb fusion in renal tumors harboring the t 6 11 p21 q13 chromosome translocation
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Ian J. Davis, Patricia Valencia, Antonio R Perezatayde, Jonathan A Fletcher, Marc Ladanyi, Jason D Arroyo, Gabriela Motyckova, Pedram Argani, Sara O Vargas, David E. FisherAbstract:MITF, TFE3, TFEB, and TFEC comprise a transcription factor family (MiT) that regulates key developmental pathways in several cell lineages. Like MYC, MiT members are basic helix-loop-helix-leucine zipper transcription factors. MiT members share virtually perfect homology in their DNA binding domains and bind a common DNA motif. Translocations of TFE3 occur in specific subsets of human renal cell carcinomas and in alveolar soft part sarcomas. Although multiple translocation partners are fused to TFE3, each translocation product retains TFE3's basic helix–loop–helix leucine zipper. We have identified the genes fused by the chromosomal translocation t(6;11)(p21.1;q13), characteristic of another subset of renal neoplasms. In two primary tumors we found that Alpha, an intronless gene, rearranges with the first intron of TFEB, just upstream of TFEB's initiation ATG, preserving the entire TFEB coding sequence. Fluorescence in situ hybridization confirmed the involvement of both TFEB and Alpha in this translocation. Although the Alpha promoter drives expression of this fusion gene, the Alpha gene does not contribute to the ORF. Whereas TFE3 is typically fused to partner proteins in subsets of renal tumors, we found that wild-type, unfused TFE3 stimulates clonogenic growth in a cell-based assay, suggesting that dysregulated expression, rather than altered function of TFEB or TFE3 fusions, may confer neoplastic properties, a mechanism reminiscent of MYC activation by promoter substitution in Burkitt's lymphoma. Alpha-TFEB is thus identified as a fusion gene in a subset of pediatric renal neoplasms.
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RBM10-TFE3 Renal Cell Carcinoma: A Potential Diagnostic Pitfall Due to Cryptic Intrachromosomal Xp11.2 Inversion Resulting in False-negative TFE3 FISH.
The American journal of surgical pathology, 2017Co-Authors: Pedram Argani, Lei Zhang, Victor E. Reuter, Satish K. Tickoo, Cristina R. AntonescuAbstract:Xp11 translocation renal cell carcinoma (RCC) are defined by chromosome translocations involving the Xp11 breakpoint which results in one of a variety of TFE3 gene fusions. TFE3 break-apart florescence in situ hybridization (FISH) assays are generally preferred to TFE3 immunohistochemistry (IHC) as a means of confirming the diagnosis in archival material, as FISH is less sensitive to the variable fixation which can result in false positive or false negative IHC. Prompted by a case report in the cytogenetics literature, we identify 3 cases of Xp11 translocation RCC characterized by a subtle chromosomal inversion involving the short arm of the X chromosome, resulting in an RBM10-TFE3 gene fusion. TFE3 rearrangement was not detected by conventional TFE3 break-apart FISH, but was suggested by strong diffuse TFE3 immunoreactivity in a clean background. We then developed novel fosmid probes to detect the RBM10-TFE3 gene fusion in archival material. These cases validate RBM10-TFE3 as a recurrent gene fusion in Xp11 translocation RCC, illustrate a source of false-negative TFE3 break-apart FISH, and highlight the complementary role of TFE3 IHC and TFE3 FISH.
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molecular confirmation of t 6 11 p21 q12 renal cell carcinoma in archival paraffin embedded material using a break apart tfeb fish assay expands its clinicopathologic spectrum
The American Journal of Surgical Pathology, 2012Co-Authors: Pedram Argani, Laura Morsberger, Kerry Morris, Nilda González, Marc Ladanyi, Peter B Illei, Nathan Smith, Raluca Yonescu, George J Netto, Constance A GriffinAbstract:The past decade has witnessed the characterization of a subset of renal cell carcinomas (RCCs) that have chromosomal translocations resulting in gene fusions involving members of the MiT subfamily of transcription factors. The best known members of this subset are the Xp11 translocation RCCs, which were recognized by the World Health Organization in 2004.1 These neoplasms comprise the majority of pediatric RCCs and a smaller percentage of adult RCCs and classically feature a papillary architecture lined by clear cells with extensive psammomatous calcification.2–8 Xp11 translocation RCCs are characterized by gene fusions involving the TFE3 transcription factor gene that maps to this locus; at least 5 different fusion partners for TFE3 have been identified to date.2,3,5,9,10 A less well-known member of the translocation RCC family is the subset of RCCs characterized by t(6;11)(p21;q12), which results in fusion of the untranslated Alpha (MALAT1) gene on 11q12 to the related TFEB gene on 6p21.11–14 Only 21 genetically confirmed cases of t(6;11) RCCs have been reported.5,11–23 This neoplasm typically demonstrates a distinctive biphasic morphology, comprising larger epithelioid cells and smaller cells clustered around basement membrane material; however, the full spectrum of its morphologic appearances is not known. The t(6;11) RCCs differ from most conventional RCCs in that they consistently express melanocytic immunohistochemical (IHC) markers such as HMB45, Melan A, and the cysteine protease cathepsin K24,25 but are either negative or only focally positive for epithelial markers such as cytokeratins.11,12 On the basis of clinical, pathologic, and genetic similarities between the t(6;11) RCCs and the Xp11 translocation RCCs, we have proposed that these 2 neoplasms be classified together under the broader category of “MiT family translocation RCC.”12 Molecular confirmation of a diagnosis of a translocation RCC is relatively simple if fresh tissue is available for either cytogenetics or reverse transcriptase polymerase chain reaction assay using primers from the genes known to be involved in the gene fusion. However, in many cases, only archival, formalin-fixed, paraffin-embedded material is available. For the Xp11 translocation RCCs and t(6;11) RCCs, IHC for TFE3 and TFEB, respectively, have proven to be useful for confirming the diagnosis in archival material.6,12 This is because both TFE3 fusion proteins and native TFEB are upregulated by promoter substitution by the gene fusions in these 2 RCCs relative to the level of expression of the respective native proteins. However, IHC is highly fixation dependent and has proven to be particularly difficult for TFE3 and TFEB for several reasons. These include the scarcity of genetically confirmed positive controls and the fact that the assays are optimally performed by overnight incubation, which is difficult to automate.26 Recently, break-apart fluorescence in situ hybridization (FISH) assays for TFE3 gene fusions were developed for archival material27–29 and have allowed the expansion of the morphologic spectrum of the Xp11 translocation RCCs.30 A validated FISH assay for molecular confirmation of t(6;11) RCC has not been reported previously. We report herein the development of a break-apart TFEB FISH assay for the diagnosis of t(6;11)(p21;q12) RCCs. We validated the assay on 4 genetically confirmed cases and 76 pertinent negative control cases, confirmed the presence of a TFEB gene rearrangement in a previously reported TFEB IHC-positive case from 46 years ago, and used the assay to report 8 new cases that expanded the clinicopathologic spectrum of t(6;11) RCCs.
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perivascular epithelioid cell tumors pecomas harboring TFE3 gene rearrangements lack the tsc2 alterations characteristic of conventional pecomas further evidence for a biological distinction
The American Journal of Surgical Pathology, 2012Co-Authors: Izabela A Malinowska, Guido Martignoni, Sharon W Weiss, George J Netto, David J Kwiatkowski, Pedram ArganiAbstract:Perivascular epithelioid cell neoplasms (PEComas) are a group of lesions composed of distinctive perivascular epithelioid cells which typically demonstrate both melanocytic and muscular differentiation. This family includes the common renal angiomyolipoma, pulmonary clear cell sugar tumor, lymphangioleiomyomatosis, and less common neoplasms of the soft tissue, gynecologic and gastrointestinal tracts (7, 8, 9, 14, 16, 19). The cells comprising these lesions may be variably epithelioid or spindled in shape, and have variable cytoplasm ranging from clear to eosinophilic. By immunohistochemistry (IHC), PEComas typically express the melanocytic markers HMB45 and Melan-A and the protease Cathepsin K (18), but also typically label for smooth muscle actin and may express desmin. Some members of the PEComa family (specifically angiomyolipoma and lymphangioleiomyomatosis) are seen with high frequency in the genetic syndrome Tuberous Sclerosis Complex (TSC) (16), and a high frequency of syndromic and sporadic PEComas have demonstrated inactivation of the TSC1 or TSC2 genes (12, 20, 21) with subsequent activation of the mammalian target of rapamycin (mTOR) pathway (15). Specifically, mutation in and loss of heterozygosity (LOH) of TSC2 with loss of expression of the protein tuberin, the protein encoded by TSC2, is consistently found in conventional PEComas. TFE3 is a member of the MiT family of transcription factors, which includes MiTF, TFEB, TFEC, and TFE3 (11). TFE3 gene fusions are known to occur in several types of neoplasia. Alveolar soft part sarcoma (ASPS), a rare epithelioid cell soft tissue sarcoma of uncertain histogenesis, characteristically demonstrates a der (17) t(X;17)(p11;q25) resulting in an ASPL-TFE3 gene fusion (17). In addition, a group of recently-described renal cell carcinomas (RCCs) which often occur in children bear various TFE3 gene fusions; these are designated the Xp11 translocation RCC (1, 2, 5, 6). Moreover, a distinctive subgroup of renal cancers in young patients with overlapping features of melanoma, RCC and PEComas have also proven to harbor TFE3 gene fusions (3). Finally, we have recently identified a subgroup of lesions currently characterized as PEComas which, in contrast to conventional PEComas, harbor TFE3 gene fusions (4). Although the number of cases identified are small, distinctive features of these TFE3-rearranged PEComas include a tendency to young age, absence of the association with tuberous sclerosis, predominant alveolar architecture and epithelioid cytology, minimal immunoreactivity for muscle markers, and strong (3+) TFE3 immunoreactivity. In contrast, conventional PEComas frequently have a spindle cell component, typically label for muscle markers, lack strong TFE3 immunoreactivity, and in young patients are frequently associated with tuberous sclerosis. Since conventional PEComas frequently demonstrate TSC2 LOH, and loss of expression of the tuberin protein which this gene encodes (13), we evaluated TFE3-rearranged PEComas for TSC2 LOH and for tuberin expression by IHC. The study cohort consisted of four PEComas previously shown to harbor TFE3 gene fusions (4), and four conventional PEComas which lacked TFE3 alterations. To assess LOH or allelic loss we performed analysis of three microsatellite markers, STR3, KG8 and STR7 in the region of the TSC2 gene, on paraffin-extracted DNA from tumor and normal tissue as described elsewhere (21). IHC was performed by standard techniques using Target Retrieval Solution pH 6.1 (Dako), incubation with anti-tuberin antibody (1:200 dilution, Cell Signaling, #4308), and development with horseradish peroxidase (HRP)-conjugated secondary antibody and DAB (Dako Envision System). Slides were counterstained with hematoxylin. By IHC, all four of the conventional non-TFE3 PEComas demonstrated loss of tuberin protein labeling by immunohistochemistry, with the surrounding normal tissue serving as an internal control (Figure 1, top row). In contrast, all four of the PEComas previously shown to harbor TFE3 gene fusions demonstrated intact, robust tuberin protein labeling (Figure 1, bottom row). In addition, two of the four conventional PEComas showed LOH or allelic loss for one or more TSC2 microsatellite markers (Figure 1, top right), as we and others have seen previously (12, 15, 20). In contrast, none of the four PEComas previously shown to harbor TFE3 gene fusions demonstrated TSC2 LOH (Figure 1, bottom right). Figure1 Hematoxylin and Eosin staining, IHC for tuberin, and TSC2 microsatellite marker analysis is shown for a conventional PEComa (top row), and a TFE3-rearranged PEComa (bottom row). The insets show regions of normal tissue stained for TSC2 from each tumor ... Thus, these observations, while limited in scope due to the limited number of cases available to us, are consistent with our hypothesis that there is a different pathogenetic mechanism in TFE3-rearranged PEComas which does not involve the TSC2 gene through mutation or allelic loss, or other mechanisms of loss of expression. Thus, they suggest that TFE3-rearranged PEComas represent an entity which morphologically overlaps with conventional PEComas, but is biologically distinctive. This concept has clinical translational importance in that mTORC1 inhibitors, such as rapamycin and everolimus, have been shown to be effective in some cases of PEComas (22). If there is no TSC2 gene involvement in TFE3-rearranged PEComas, then these patients may not respond to mTORC1 inhibitors.
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a novel cltc TFE3 gene fusion in pediatric renal adenocarcinoma with t x 17 p11 2 q23
Oncogene, 2003Co-Authors: Pedram Argani, Jerome Couturier, Raymonde Bouvier, Jeanchristophe Fournet, Marc LadanyiAbstract:A distinctive subset of renal carcinomas is associated with Xp11.2 translocations and resulting TFE3 gene fusions (PRCC–TFE3, PSF–TFE3, NONO–TFE3, ASPL–TFE3), encoding related aberrant transcription factors. We report the cloning of a novel clathrin heavy-chain gene (CLTC)–TFE3 gene fusion resulting from a t(X;17)(p11.2;q23) in a renal carcinoma arising in a 14-year-old boy. The fusion transcript joined the 5′ exons of CLTC on chromosome band 17q23 to the 3′ exons of TFE3. CLTC encodes a major subunit of clathrin, a multimeric protein on cytoplasmic organelles, and is a known recurrent fusion partner of the ALK tyrosine kinase gene in anaplastic large-cell lymphoma and inflammatory myofibroblastic tumors. The predicted CLTC–TFE3 product retains the nuclear localization and DNA-binding domains of TFE3, but lacks the multimerization domain of CLTC. The present renal tumor demonstrated morphologic and immunohistochemical features of both PRCC–TFE3 and ASPL–TFE3 carcinomas, including strong nuclear immunoreactivity for the TFE3 C-terminal and only minimal expression of epithelial proteins. However, unlike most renal carcinomas, it also focally expressed melanocytic proteins. The present report highlights the promiscuity of certain genes involved in chromosomal translocations. Further analysis of the shared features of CLTC and other TFE3 fusion partners may shed light on the essential biology of TFE3 fusion proteins.
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cloning of an alpha tfeb fusion in renal tumors harboring the t 6 11 p21 q13 chromosome translocation
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Ian J. Davis, Patricia Valencia, Antonio R Perezatayde, Jonathan A Fletcher, Marc Ladanyi, Jason D Arroyo, Gabriela Motyckova, Pedram Argani, Sara O Vargas, David E. FisherAbstract:MITF, TFE3, TFEB, and TFEC comprise a transcription factor family (MiT) that regulates key developmental pathways in several cell lineages. Like MYC, MiT members are basic helix-loop-helix-leucine zipper transcription factors. MiT members share virtually perfect homology in their DNA binding domains and bind a common DNA motif. Translocations of TFE3 occur in specific subsets of human renal cell carcinomas and in alveolar soft part sarcomas. Although multiple translocation partners are fused to TFE3, each translocation product retains TFE3's basic helix–loop–helix leucine zipper. We have identified the genes fused by the chromosomal translocation t(6;11)(p21.1;q13), characteristic of another subset of renal neoplasms. In two primary tumors we found that Alpha, an intronless gene, rearranges with the first intron of TFEB, just upstream of TFEB's initiation ATG, preserving the entire TFEB coding sequence. Fluorescence in situ hybridization confirmed the involvement of both TFEB and Alpha in this translocation. Although the Alpha promoter drives expression of this fusion gene, the Alpha gene does not contribute to the ORF. Whereas TFE3 is typically fused to partner proteins in subsets of renal tumors, we found that wild-type, unfused TFE3 stimulates clonogenic growth in a cell-based assay, suggesting that dysregulated expression, rather than altered function of TFEB or TFE3 fusions, may confer neoplastic properties, a mechanism reminiscent of MYC activation by promoter substitution in Burkitt's lymphoma. Alpha-TFEB is thus identified as a fusion gene in a subset of pediatric renal neoplasms.