The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Oscar A Vega - One of the best experts on this subject based on the ideXlab platform.
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wnt β catenin signaling activates expression of the bone related transcription factor runx2 in select human Osteosarcoma Cell types
Journal of Cellular Biochemistry, 2017Co-Authors: Oscar A Vega, Claudia M J Lucero, Julio C Tapia, Hector F. Araya, Sofia Jerez, Roman Thaler, Flavio Salazaronfray, Facundo Las Heras, Marcelo Antonelli, Scott M RiesterAbstract:: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Metastasis and poor responsiveness to chemotherapy in Osteosarcoma correlates with over-expression of the runt-related transcription factor RUNX2, which normally plays a key role in osteogenic lineage commitment, osteoblast differentiation, and bone formation. Furthermore, WNT/β-catenin signaling is over-activated in Osteosarcoma and promotes tumor progression. Importantly, the WNT/β-catenin pathway normally activates RUNX2 gene expression during osteogenic lineage commitment. Therefore, we examined whether the WNT/β-catenin pathway controls the tumor-related elevation of RUNX2 expression in Osteosarcoma. We analyzed protein levels and nuclear localization of β-catenin and RUNX2 in a panel of human Osteosarcoma Cell lines (SAOS, MG63, U2OS, HOS, G292, and 143B). In all six Cell lines, β-catenin and RUNX2 are expressed to different degrees and localized in the nucleus and/or cytoplasm. SAOS Cells have the highest levels of RUNX2 protein that is localized in the nucleus, while MG63 Cells have the lowest RUNX2 levels which is mostly localized in the cytoplasm. Levels of β-catenin and RUNX2 protein are enhanced in HOS, G292, and 143B Cells after treatment with the GSK3β inhibitor SB216763. Furthermore, small interfering RNA (siRNA)-mediated depletion of β-catenin inhibits RUNX2 expression in G292 Cells. Thus, WNT/β-catenin activation is required for RUNX2 expression in at least some Osteosarcoma Cell types, where RUNX2 is known to promote expression of metastasis related genes. J. Cell. Biochem. 118: 3662-3674, 2017. © 2017 Wiley Periodicals, Inc.
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the cancer related transcription factor runx2 modulates Cell proliferation in human Osteosarcoma Cell lines
Journal of Cellular Physiology, 2013Co-Authors: Claudia M J Lucero, Oscar A Vega, Mariana Osorio, Julio C Tapia, Andre J Van Wijnen, Gary S Stein, Marcelo Antonelli, Mario GalindoAbstract:Osteosarcoma is the most common bone tumor in children and adolescents (Young and Miller, 1975). The highest incidence of Osteosarcoma is in the second decade of life, which suggests a relationship between bone growth and tumor development (Fraumeni, 1967; Cotterill et al., 2004). One of the critical steps for normal skeletal development and bone formation is the proliferative expansion of mesenchymal Cells, osteoprogenitors, and immature osteoblasts. Cell growth and differentiation of normal osteoprogenitors and pre-osteoblasts is tightly regulated by Runx2, which favors a quiescent state (Pratap et al., 2003; Galindo et al., 2005). The growth suppressive potential of Runx2 is controlled by modulation of its protein levels during the Cell cycle (Galindo et al., 2005, 2007). Cell cycle dependent changes of Runx2 levels occur with respect to G1 progression at a Cell cycle stage when normal osteoblasts monitor extra-Cellular cues for competency to initiate Cell cycle progression beyond the G1/S phase transition. Accordingly, transient Runx2 overexpression in synchronized Cells delays Cell cycle entry into S phase and significantly decreases Cell proliferation in the MC3T3 pre-osteoblasts, Runx2 null calvarian osteoprogenitors, C2C12 pluripotent mesenchymal, and IMR-90 fibroblasts Cell lines (Pratap et al., 2003; Galindo et al., 2005; Young et al., 2007a; Teplyuk et al., 2008, 2009a). The function of Runx2 as a negative regulator of Cell proliferation is also reflected by linkage of Runx2 deficiency to Cell immortalization and tumorigenesis (Kilbey et al., 2007; Zaidi et al., 2007a). Apart from the growth suppressive potential that is evident during late G1 in osteoblasts (Pratap et al., 2003; Galindo et al., 2005), Runx2 may have mitogenic potential in early G1 (Teplyuk et al., 2008). Several studies indicate that Runx2-dependent control of proliferation is Cell type-specific. Runx2 inhibits proliferation of osteoprogenitors and committed osteoblasts (Pratap et al., 2003; Galindo et al., 2005), but it may have distinct biological roles in chondrocytes (Galindo et al., 2005; Hinoi et al., 2006; Komori, 2008) and endothelial Cells (Inman and Shore, 2003; Qiao et al., 2006). While immature osteoblasts from mice with Runx2 null mutations show accelerated proliferative potential, chondrocyte proliferation seems to be decreased in Runx2 null mice (Pratap et al., 2003; Yoshida et al., 2004), suggesting that Runx2 would also have opposites roles in different bone Cell types. Moreover, ectopic expression of Runx2 in aortic endothelial Cells increases Cell proliferation (Sun et al., 2004), whereas Runx2 depletion inhibits Cell proliferation in human marrow endothelial Cells (Qiao et al., 2006). These findings support the concept that Runx2 protein can function as either a bona fide tumor suppressor or a classical oncoprotein depending on the Cellular context (Blyth et al., 2005). Current evidence indicates that Runx2 expression is a key pathological factor in Osteosarcoma (Martin et al., 2011) by controlling a number of cancer-related genes (van der Deen et al., 2012). Moreover, Osteosarcoma development may be associated with Runx2 overexpression and defects in osteogenic differentiation (Wagner et al., 2011). Over-expression of Runx2 in transgenic mice within the osteoblast lineage inhibits osteoblast maturation, increases bone resorption, and causes osteopenia with multiple fractures (Liu et al., 2001; Geoffroy et al., 2002). Runx2 is also clearly detected in clinical Osteosarcoma samples (Andela et al., 2005; Lu et al., 2008; Sadikovic et al., 2009; Won et al., 2009; Kurek et al., 2010). Analysis of genomic DNA from Osteosarcoma patients with amplication of the 6p12#x02013;p21 chromosomal interval, which spans the Runx2 locus, increases the Runx2 gene copy number and aberrantly elevates Runx2 expression (Lau et al., 2004; Lu et al., 2008; Sadikovic et al., 2009). Increased expression of Runx2 in Osteosarcoma biopsies has been associated to increased tumorigenicity, tumor progression, metastases, lower survival, and poor prognosis (Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Interestingly, Osteosarcoma Cell culture models may exhibit a similar variability of Runx2 gene expression, because Runx2 is expressed at different levels in a number of human Osteosarcoma Cell lines (Thomas et al., 2004; Lu et al., 2008; Luo et al., 2008; Kurek et al., 2010; Shapovalov et al., 2010). A subset of patient-derived Osteosarcoma Cell lines exhibit high levels of Runx2, whereas others show decreased Runx2 expression in accordance with the findings of Thomas and colleagues who suggested that Runx2 protein levels are negatively regulated in some types of Osteosarcoma (Thomas et al., 2004; Nathan et al., 2009; Pereira et al., 2009; San Martin et al., 2009; Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Recently, we presented data indicating that Cell cycle control of Runx2, which is readily observed in osteoblasts, is deregulated in Osteosarcoma Cells (Galindo et al., 2005; San Martin et al., 2009). Runx2 is constitutively expressed throughout the Cell cycle in at least two Osteosarcoma (human SaOS and rat ROS) Cell lines (Young et al., 2007b; San Martin et al., 2009). Hence, the transcriptional and post-transcriptional mechanisms that mediate Cell cycle control of Runx2 gene expression in osteoblasts could be compromised in Osteosarcoma Cells. The latter may occur in conjunction with abrogation of other molecular mechanisms Cells that mediate normal osteoblast proliferation and that may bypass the growth suppressive properties of Runx2 in bone cancer Cells (Nathan et al., 2009). In this article, we systematically examined human Osteosarcoma Cell lines with respect to Runx2 gene expression and Cell cycle regulation to understand the biological functions of Runx2 in Osteosarcoma Cell proliferation. Our main finding is that forced expression of Runx2 suppresses growth in all Cell lines, indicating that stimulation of Runx2 beyond its preestablished levels in Osteosarcoma Cells remains capable of triggering an anti-proliferative response. We propose that Osteosarcoma Cells in which Runx2 is present must balance prooncogenic functions of Runx2 with the requirement to maintain Runx2 at levels that avoid tumor suppression.
Claudia M J Lucero - One of the best experts on this subject based on the ideXlab platform.
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wnt β catenin signaling activates expression of the bone related transcription factor runx2 in select human Osteosarcoma Cell types
Journal of Cellular Biochemistry, 2017Co-Authors: Oscar A Vega, Claudia M J Lucero, Julio C Tapia, Hector F. Araya, Sofia Jerez, Roman Thaler, Flavio Salazaronfray, Facundo Las Heras, Marcelo Antonelli, Scott M RiesterAbstract:: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Metastasis and poor responsiveness to chemotherapy in Osteosarcoma correlates with over-expression of the runt-related transcription factor RUNX2, which normally plays a key role in osteogenic lineage commitment, osteoblast differentiation, and bone formation. Furthermore, WNT/β-catenin signaling is over-activated in Osteosarcoma and promotes tumor progression. Importantly, the WNT/β-catenin pathway normally activates RUNX2 gene expression during osteogenic lineage commitment. Therefore, we examined whether the WNT/β-catenin pathway controls the tumor-related elevation of RUNX2 expression in Osteosarcoma. We analyzed protein levels and nuclear localization of β-catenin and RUNX2 in a panel of human Osteosarcoma Cell lines (SAOS, MG63, U2OS, HOS, G292, and 143B). In all six Cell lines, β-catenin and RUNX2 are expressed to different degrees and localized in the nucleus and/or cytoplasm. SAOS Cells have the highest levels of RUNX2 protein that is localized in the nucleus, while MG63 Cells have the lowest RUNX2 levels which is mostly localized in the cytoplasm. Levels of β-catenin and RUNX2 protein are enhanced in HOS, G292, and 143B Cells after treatment with the GSK3β inhibitor SB216763. Furthermore, small interfering RNA (siRNA)-mediated depletion of β-catenin inhibits RUNX2 expression in G292 Cells. Thus, WNT/β-catenin activation is required for RUNX2 expression in at least some Osteosarcoma Cell types, where RUNX2 is known to promote expression of metastasis related genes. J. Cell. Biochem. 118: 3662-3674, 2017. © 2017 Wiley Periodicals, Inc.
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the cancer related transcription factor runx2 modulates Cell proliferation in human Osteosarcoma Cell lines
Journal of Cellular Physiology, 2013Co-Authors: Claudia M J Lucero, Oscar A Vega, Mariana Osorio, Julio C Tapia, Andre J Van Wijnen, Gary S Stein, Marcelo Antonelli, Mario GalindoAbstract:Osteosarcoma is the most common bone tumor in children and adolescents (Young and Miller, 1975). The highest incidence of Osteosarcoma is in the second decade of life, which suggests a relationship between bone growth and tumor development (Fraumeni, 1967; Cotterill et al., 2004). One of the critical steps for normal skeletal development and bone formation is the proliferative expansion of mesenchymal Cells, osteoprogenitors, and immature osteoblasts. Cell growth and differentiation of normal osteoprogenitors and pre-osteoblasts is tightly regulated by Runx2, which favors a quiescent state (Pratap et al., 2003; Galindo et al., 2005). The growth suppressive potential of Runx2 is controlled by modulation of its protein levels during the Cell cycle (Galindo et al., 2005, 2007). Cell cycle dependent changes of Runx2 levels occur with respect to G1 progression at a Cell cycle stage when normal osteoblasts monitor extra-Cellular cues for competency to initiate Cell cycle progression beyond the G1/S phase transition. Accordingly, transient Runx2 overexpression in synchronized Cells delays Cell cycle entry into S phase and significantly decreases Cell proliferation in the MC3T3 pre-osteoblasts, Runx2 null calvarian osteoprogenitors, C2C12 pluripotent mesenchymal, and IMR-90 fibroblasts Cell lines (Pratap et al., 2003; Galindo et al., 2005; Young et al., 2007a; Teplyuk et al., 2008, 2009a). The function of Runx2 as a negative regulator of Cell proliferation is also reflected by linkage of Runx2 deficiency to Cell immortalization and tumorigenesis (Kilbey et al., 2007; Zaidi et al., 2007a). Apart from the growth suppressive potential that is evident during late G1 in osteoblasts (Pratap et al., 2003; Galindo et al., 2005), Runx2 may have mitogenic potential in early G1 (Teplyuk et al., 2008). Several studies indicate that Runx2-dependent control of proliferation is Cell type-specific. Runx2 inhibits proliferation of osteoprogenitors and committed osteoblasts (Pratap et al., 2003; Galindo et al., 2005), but it may have distinct biological roles in chondrocytes (Galindo et al., 2005; Hinoi et al., 2006; Komori, 2008) and endothelial Cells (Inman and Shore, 2003; Qiao et al., 2006). While immature osteoblasts from mice with Runx2 null mutations show accelerated proliferative potential, chondrocyte proliferation seems to be decreased in Runx2 null mice (Pratap et al., 2003; Yoshida et al., 2004), suggesting that Runx2 would also have opposites roles in different bone Cell types. Moreover, ectopic expression of Runx2 in aortic endothelial Cells increases Cell proliferation (Sun et al., 2004), whereas Runx2 depletion inhibits Cell proliferation in human marrow endothelial Cells (Qiao et al., 2006). These findings support the concept that Runx2 protein can function as either a bona fide tumor suppressor or a classical oncoprotein depending on the Cellular context (Blyth et al., 2005). Current evidence indicates that Runx2 expression is a key pathological factor in Osteosarcoma (Martin et al., 2011) by controlling a number of cancer-related genes (van der Deen et al., 2012). Moreover, Osteosarcoma development may be associated with Runx2 overexpression and defects in osteogenic differentiation (Wagner et al., 2011). Over-expression of Runx2 in transgenic mice within the osteoblast lineage inhibits osteoblast maturation, increases bone resorption, and causes osteopenia with multiple fractures (Liu et al., 2001; Geoffroy et al., 2002). Runx2 is also clearly detected in clinical Osteosarcoma samples (Andela et al., 2005; Lu et al., 2008; Sadikovic et al., 2009; Won et al., 2009; Kurek et al., 2010). Analysis of genomic DNA from Osteosarcoma patients with amplication of the 6p12#x02013;p21 chromosomal interval, which spans the Runx2 locus, increases the Runx2 gene copy number and aberrantly elevates Runx2 expression (Lau et al., 2004; Lu et al., 2008; Sadikovic et al., 2009). Increased expression of Runx2 in Osteosarcoma biopsies has been associated to increased tumorigenicity, tumor progression, metastases, lower survival, and poor prognosis (Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Interestingly, Osteosarcoma Cell culture models may exhibit a similar variability of Runx2 gene expression, because Runx2 is expressed at different levels in a number of human Osteosarcoma Cell lines (Thomas et al., 2004; Lu et al., 2008; Luo et al., 2008; Kurek et al., 2010; Shapovalov et al., 2010). A subset of patient-derived Osteosarcoma Cell lines exhibit high levels of Runx2, whereas others show decreased Runx2 expression in accordance with the findings of Thomas and colleagues who suggested that Runx2 protein levels are negatively regulated in some types of Osteosarcoma (Thomas et al., 2004; Nathan et al., 2009; Pereira et al., 2009; San Martin et al., 2009; Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Recently, we presented data indicating that Cell cycle control of Runx2, which is readily observed in osteoblasts, is deregulated in Osteosarcoma Cells (Galindo et al., 2005; San Martin et al., 2009). Runx2 is constitutively expressed throughout the Cell cycle in at least two Osteosarcoma (human SaOS and rat ROS) Cell lines (Young et al., 2007b; San Martin et al., 2009). Hence, the transcriptional and post-transcriptional mechanisms that mediate Cell cycle control of Runx2 gene expression in osteoblasts could be compromised in Osteosarcoma Cells. The latter may occur in conjunction with abrogation of other molecular mechanisms Cells that mediate normal osteoblast proliferation and that may bypass the growth suppressive properties of Runx2 in bone cancer Cells (Nathan et al., 2009). In this article, we systematically examined human Osteosarcoma Cell lines with respect to Runx2 gene expression and Cell cycle regulation to understand the biological functions of Runx2 in Osteosarcoma Cell proliferation. Our main finding is that forced expression of Runx2 suppresses growth in all Cell lines, indicating that stimulation of Runx2 beyond its preestablished levels in Osteosarcoma Cells remains capable of triggering an anti-proliferative response. We propose that Osteosarcoma Cells in which Runx2 is present must balance prooncogenic functions of Runx2 with the requirement to maintain Runx2 at levels that avoid tumor suppression.
Scott M Riester - One of the best experts on this subject based on the ideXlab platform.
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wnt β catenin signaling activates expression of the bone related transcription factor runx2 in select human Osteosarcoma Cell types
Journal of Cellular Biochemistry, 2017Co-Authors: Oscar A Vega, Claudia M J Lucero, Julio C Tapia, Hector F. Araya, Sofia Jerez, Roman Thaler, Flavio Salazaronfray, Facundo Las Heras, Marcelo Antonelli, Scott M RiesterAbstract:: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Metastasis and poor responsiveness to chemotherapy in Osteosarcoma correlates with over-expression of the runt-related transcription factor RUNX2, which normally plays a key role in osteogenic lineage commitment, osteoblast differentiation, and bone formation. Furthermore, WNT/β-catenin signaling is over-activated in Osteosarcoma and promotes tumor progression. Importantly, the WNT/β-catenin pathway normally activates RUNX2 gene expression during osteogenic lineage commitment. Therefore, we examined whether the WNT/β-catenin pathway controls the tumor-related elevation of RUNX2 expression in Osteosarcoma. We analyzed protein levels and nuclear localization of β-catenin and RUNX2 in a panel of human Osteosarcoma Cell lines (SAOS, MG63, U2OS, HOS, G292, and 143B). In all six Cell lines, β-catenin and RUNX2 are expressed to different degrees and localized in the nucleus and/or cytoplasm. SAOS Cells have the highest levels of RUNX2 protein that is localized in the nucleus, while MG63 Cells have the lowest RUNX2 levels which is mostly localized in the cytoplasm. Levels of β-catenin and RUNX2 protein are enhanced in HOS, G292, and 143B Cells after treatment with the GSK3β inhibitor SB216763. Furthermore, small interfering RNA (siRNA)-mediated depletion of β-catenin inhibits RUNX2 expression in G292 Cells. Thus, WNT/β-catenin activation is required for RUNX2 expression in at least some Osteosarcoma Cell types, where RUNX2 is known to promote expression of metastasis related genes. J. Cell. Biochem. 118: 3662-3674, 2017. © 2017 Wiley Periodicals, Inc.
Mario Galindo - One of the best experts on this subject based on the ideXlab platform.
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the cancer related transcription factor runx2 modulates Cell proliferation in human Osteosarcoma Cell lines
Journal of Cellular Physiology, 2013Co-Authors: Claudia M J Lucero, Oscar A Vega, Mariana Osorio, Julio C Tapia, Andre J Van Wijnen, Gary S Stein, Marcelo Antonelli, Mario GalindoAbstract:Osteosarcoma is the most common bone tumor in children and adolescents (Young and Miller, 1975). The highest incidence of Osteosarcoma is in the second decade of life, which suggests a relationship between bone growth and tumor development (Fraumeni, 1967; Cotterill et al., 2004). One of the critical steps for normal skeletal development and bone formation is the proliferative expansion of mesenchymal Cells, osteoprogenitors, and immature osteoblasts. Cell growth and differentiation of normal osteoprogenitors and pre-osteoblasts is tightly regulated by Runx2, which favors a quiescent state (Pratap et al., 2003; Galindo et al., 2005). The growth suppressive potential of Runx2 is controlled by modulation of its protein levels during the Cell cycle (Galindo et al., 2005, 2007). Cell cycle dependent changes of Runx2 levels occur with respect to G1 progression at a Cell cycle stage when normal osteoblasts monitor extra-Cellular cues for competency to initiate Cell cycle progression beyond the G1/S phase transition. Accordingly, transient Runx2 overexpression in synchronized Cells delays Cell cycle entry into S phase and significantly decreases Cell proliferation in the MC3T3 pre-osteoblasts, Runx2 null calvarian osteoprogenitors, C2C12 pluripotent mesenchymal, and IMR-90 fibroblasts Cell lines (Pratap et al., 2003; Galindo et al., 2005; Young et al., 2007a; Teplyuk et al., 2008, 2009a). The function of Runx2 as a negative regulator of Cell proliferation is also reflected by linkage of Runx2 deficiency to Cell immortalization and tumorigenesis (Kilbey et al., 2007; Zaidi et al., 2007a). Apart from the growth suppressive potential that is evident during late G1 in osteoblasts (Pratap et al., 2003; Galindo et al., 2005), Runx2 may have mitogenic potential in early G1 (Teplyuk et al., 2008). Several studies indicate that Runx2-dependent control of proliferation is Cell type-specific. Runx2 inhibits proliferation of osteoprogenitors and committed osteoblasts (Pratap et al., 2003; Galindo et al., 2005), but it may have distinct biological roles in chondrocytes (Galindo et al., 2005; Hinoi et al., 2006; Komori, 2008) and endothelial Cells (Inman and Shore, 2003; Qiao et al., 2006). While immature osteoblasts from mice with Runx2 null mutations show accelerated proliferative potential, chondrocyte proliferation seems to be decreased in Runx2 null mice (Pratap et al., 2003; Yoshida et al., 2004), suggesting that Runx2 would also have opposites roles in different bone Cell types. Moreover, ectopic expression of Runx2 in aortic endothelial Cells increases Cell proliferation (Sun et al., 2004), whereas Runx2 depletion inhibits Cell proliferation in human marrow endothelial Cells (Qiao et al., 2006). These findings support the concept that Runx2 protein can function as either a bona fide tumor suppressor or a classical oncoprotein depending on the Cellular context (Blyth et al., 2005). Current evidence indicates that Runx2 expression is a key pathological factor in Osteosarcoma (Martin et al., 2011) by controlling a number of cancer-related genes (van der Deen et al., 2012). Moreover, Osteosarcoma development may be associated with Runx2 overexpression and defects in osteogenic differentiation (Wagner et al., 2011). Over-expression of Runx2 in transgenic mice within the osteoblast lineage inhibits osteoblast maturation, increases bone resorption, and causes osteopenia with multiple fractures (Liu et al., 2001; Geoffroy et al., 2002). Runx2 is also clearly detected in clinical Osteosarcoma samples (Andela et al., 2005; Lu et al., 2008; Sadikovic et al., 2009; Won et al., 2009; Kurek et al., 2010). Analysis of genomic DNA from Osteosarcoma patients with amplication of the 6p12#x02013;p21 chromosomal interval, which spans the Runx2 locus, increases the Runx2 gene copy number and aberrantly elevates Runx2 expression (Lau et al., 2004; Lu et al., 2008; Sadikovic et al., 2009). Increased expression of Runx2 in Osteosarcoma biopsies has been associated to increased tumorigenicity, tumor progression, metastases, lower survival, and poor prognosis (Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Interestingly, Osteosarcoma Cell culture models may exhibit a similar variability of Runx2 gene expression, because Runx2 is expressed at different levels in a number of human Osteosarcoma Cell lines (Thomas et al., 2004; Lu et al., 2008; Luo et al., 2008; Kurek et al., 2010; Shapovalov et al., 2010). A subset of patient-derived Osteosarcoma Cell lines exhibit high levels of Runx2, whereas others show decreased Runx2 expression in accordance with the findings of Thomas and colleagues who suggested that Runx2 protein levels are negatively regulated in some types of Osteosarcoma (Thomas et al., 2004; Nathan et al., 2009; Pereira et al., 2009; San Martin et al., 2009; Won et al., 2009; Kurek et al., 2010; Sadikovic et al., 2010). Recently, we presented data indicating that Cell cycle control of Runx2, which is readily observed in osteoblasts, is deregulated in Osteosarcoma Cells (Galindo et al., 2005; San Martin et al., 2009). Runx2 is constitutively expressed throughout the Cell cycle in at least two Osteosarcoma (human SaOS and rat ROS) Cell lines (Young et al., 2007b; San Martin et al., 2009). Hence, the transcriptional and post-transcriptional mechanisms that mediate Cell cycle control of Runx2 gene expression in osteoblasts could be compromised in Osteosarcoma Cells. The latter may occur in conjunction with abrogation of other molecular mechanisms Cells that mediate normal osteoblast proliferation and that may bypass the growth suppressive properties of Runx2 in bone cancer Cells (Nathan et al., 2009). In this article, we systematically examined human Osteosarcoma Cell lines with respect to Runx2 gene expression and Cell cycle regulation to understand the biological functions of Runx2 in Osteosarcoma Cell proliferation. Our main finding is that forced expression of Runx2 suppresses growth in all Cell lines, indicating that stimulation of Runx2 beyond its preestablished levels in Osteosarcoma Cells remains capable of triggering an anti-proliferative response. We propose that Osteosarcoma Cells in which Runx2 is present must balance prooncogenic functions of Runx2 with the requirement to maintain Runx2 at levels that avoid tumor suppression.
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runx2 p53 and prb status as diagnostic parameters for deregulation of osteoblast growth and differentiation in a new pre chemotherapeutic Osteosarcoma Cell line os1
Journal of Cellular Physiology, 2009Co-Authors: Barry P Pereira, Mario Galindo, Yefang Zhou, Anurag Gupta, David Tai Leong, Khin Zarchi Aung, Ling Ling, R W H Pho, Manuel Saltotellez, Gary S SteinAbstract:Osteosarcomas are the most prevalent primary bone tumors found in pediatric patients. To understand their molecular etiology, Cell culture models are used to define disease mechanisms under controlled conditions. Many Osteosarcoma Cell lines (e.g., SAOS-2, U2OS, MG63) are derived from Caucasian patients. However, patients exhibit individual and ethnic differences in their responsiveness to irradiation and chemotherapy. This motivated the establishment of Osteosarcoma Cell lines (OS1, OS2, OS3) from three ethnically Chinese patients. OS1 Cells, derived from a pre-chemotherapeutic tumor in the femur of a 6-year-old female, were examined for molecular markers characteristic for osteoblasts, stem Cells and Cell cycle control by immunohistochemistry, reverse transcriptase-PCR, western blotting and flow cytometry. OS1 have aberrant G-banded karyotypes, possibly reflecting chromosomal abnormalities related to p53 deficiency. OS1 had ossification profiles similar to human fetal osteoblasts rather than SAOS-2 which ossifies ab initio (p<0.05). Absence of p53 correlates with increased Runx2 expression, while the slow proliferation of OS1 Cells is perhaps attenuated by pRB retention. OS1 express mesenchymal stem Cell markers (CD44, CD105) and differ in relative expression of CD29, CD63 and CD71 to SAOS-2. (p<0.05). Cell cycle synchronization with nocodazole did not affect Runx2 and CDK1 levels but decreased cyclin-E and increased cyclin-A (p<0.05). Xenotransplantion of OS1 in SCID mice yields spontaneous tumors that were larger and grew faster than SAOS-2 transplants. Hence, OS1 is a new Osteosarcoma Cell culture model derived from a pre-chemotherapeutic ethnic Chinese patient, for mechanistic studies and development of therapeutic strategies to counteract metastasis and deregulation of mesenchymal development.
Zhenfeng Duan - One of the best experts on this subject based on the ideXlab platform.
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abstract 1781 transcriptional activation of cbfβ by cdk11p110 is necessary to promote Osteosarcoma Cell proliferation
Cancer Research, 2019Co-Authors: Yong Feng, Francis J Hornicek, Zhenfeng DuanAbstract:Aberrant expression and activation of cyclin-dependent protein kinase (CDK) is a hallmark of cancer. CDK11 is a protein kinase in the CDK family and plays a crucial role in cancer Cell growth and proliferation. However, the molecular mechanisms of CDK11 in Osteosarcoma and CDK11 transcriptional regulated genes are largely unknown. In this study, we performed global transcriptional analysis using gene array technology to investigate the transcriptional role of CDK11 in Osteosarcoma. The promoter luciferase assay, chromatin immunoprecipitation assay, and Gel Shift assay were used to identify direct transcriptional target of CDK11. Clinical significance relevance and function of CBFβ were further accessed in Osteosarcoma tissue microarray and in Osteosarcoma Cell lines. We identified a transcriptional role of protein-DNA interaction for CDK11p110, but not CDK11p58, in the regulation of core-binding factor subunit beta (CBFβ) expression in Osteosarcoma Cells. The CBFβ promoter luciferase assay, chromatin immunoprecipitation assay, and Gel Shift assay confirmed that CBFβ is a direct transcriptional target of CDK11. High expression of CBFβ is associated with poor outcome in Osteosarcoma patients. Expression of CBFβ contributes to the proliferation and metastatic behavior of Osteosarcoma Cells. These data establish CBFβas a mediator of CDK11p110dependent oncogenesis and suggest that targeting the CDK11-CBFβ pathway may be a promising therapeutic strategy for Osteosarcoma treatment. Citation Format: Yong Feng, Francis Hornicek, Zhenfeng Duan. Transcriptional activation of CBFβ by CDK11p110 is necessary to promote Osteosarcoma Cell proliferation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1781.
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p53 overexpression increases chemosensitivity in multidrug resistant Osteosarcoma Cell lines
Cancer Chemotherapy and Pharmacology, 2016Co-Authors: Jacson Shen, Edwin Choy, Cao Yang, Henry J Mankin, Francis J Hornicek, Zhenfeng DuanAbstract:Multidrug resistance (MDR) is a major obstacle to the successful treatment of Osteosarcoma with chemotherapy. Effectiveness of cancer therapy correlates with the ability to induce a p53-dependent apoptotic response. p53 is a tumor suppressor gene that is mutated in 22 % of Osteosarcomas. While impaired p53 has been implicated in the oncogenesis of Osteosarcoma, it is unclear whether overexpression of wild-type p53 can increase chemosensitivity in MDR Osteosarcoma Cells. We transfected a plasmid encoding the wild-type p53 gene to MDR Osteosarcoma Cell lines, which have different p53 statuses, U-2OSR2 with wild-type p53 (Wt-p53) and KHOSR2 with mutant p53 (Mt-p53), and determined the effect of p53 overexpression on chemosensitivities. Both of the U-2OSR2 and KHOSR2 Cell lines displayed similar trends in p53-induced drug sensitivities. However, it seems that the impact of p53 overexpression is different based on the differential intrinsic p53 status in these Cell lines. In the KHOSR2 Cell line (Mt-p53), overexpression of p53 up-regulates the expression of pro-apoptotic protein p21 and Bax, while in the U-2OSR2 Cell line (Wt-p53), overexpression of p53 down-regulates IGF-1r expression significantly. These results demonstrated that transfection of wild-type p53 increases chemosensitivity either through inhibiting IGF-1r or through increasing the expression of pro-apoptotic proteins p21 and Bax in human MDR Osteosarcoma Cell lines.
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systematic kinome shrna screening identifies cdk11 pitslre kinase expression is critical for Osteosarcoma Cell growth and proliferation
Clinical Cancer Research, 2012Co-Authors: Zhenfeng Duan, Edwin Choy, Henry J Mankin, David C Harmon, Xianzhe Liu, Jianming Zhang, Petur Nielsen, Nathanael S Gray, Francis J HornicekAbstract:Purpose: Identification of new targeted therapies is critical to improving the survival rate of patients with Osteosarcoma. The goal of this study is to identify kinase based potential therapeutic target in Osteosarcomas. Experimental Design: We used a lentiviral-based shRNA kinase library to screen for kinases which play a role in Osteosarcoma Cell survival. The Cell proliferation assay was used to evaluate Cell growth and survival. siRNA assays were applied to confirm the observed phenotypic changes resulting from the loss of kinase gene expression. CDK11 (PITSLRE) was identified as essential for the survival of Osteosarcoma Cells, and its expression was confirmed by Western blot analysis and immunohistochemistry. Overall patient survival was correlated with the CDK11 expression and its prognosis. The role of CDK11 expression in sustaining Osteosarcoma growth was further evaluated in an Osteosarcoma xenograft model in vivo . Results: Osteosarcoma Cells display high levels of CDK11 expression. CDK11 expression knocked down by either lentiviral shRNA or siRNA inhibit Cell growth and induce apoptosis in Osteosarcoma Cells. Immunohistochemical analysis showed that patients with Osteosarcoma with high CDK11 tumor expression levels were associated with significantly shorter survival than patients with Osteosarcoma with low level of tumor CDK11 expression. Systemic in vivo administration of in vivo ready siRNA of CDK11 reduced the tumor growth in an Osteosarcoma subcutaneous xenograft model. Conclusions: We show that CDK11 signaling is essential in Osteosarcoma Cell growth and survival, further elucidating the regulatory mechanisms controlling the expression of CDK11 and ultimately develop a CDK11 inhibitor that may provide therapeutic benefit against Osteosarcoma. Clin Cancer Res; 18(17); 4580–8. ©2012 AACR .
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inhibition of polo like kinase 1 leads to the suppression of Osteosarcoma Cell growth in vitro and in vivo
Anti-Cancer Drugs, 2011Co-Authors: Xianzhe Liu, Edwin Choy, Cao Yang, Henry J Mankin, Francis J Hornicek, David C Harmon, Shuhua Yang, Zhenfeng DuanAbstract:Osteosarcoma is the most common type of primary bone cancer in children and adolescents. Treatment options for Osteosarcoma may include surgery, chemotherapy, and radiotherapy. Unfortunately, many patients eventually relapse, resulting in an unsatisfactory outcome. The serine/threonine-specific polo-like kinase 1 (PLK1) is a kinase that plays an important role in mitosis and the maintenance of genomic stability. PLK1 has been found to be highly expressed in the malignant Cells of Osteosarcoma. Here, we describe the in-vitro and in-vivo effects of BI 2536, a small-molecule inhibitor of PLK1, which through inhibiting PLK1 enzymatic activity, causes mitotic arrest and eventually induces cancer Cell apoptosis. In this study, we show that the PLK1 inhibitor, BI 2536, inhibits proliferation and induces apoptosis in two-dimensional and three-dimensional cultures of Osteosarcoma Cell lines, KHOS and U-2OS. A proliferation assay performed both in two-dimensional and three-dimensional culture showed that the growth of both Cell lines was inhibited by BI 2536. Cell cycle analysis showed that the Cells treated with BI 2536 were mainly arrested in the G2/M phase. Immunofluorescence and western blotting analysis confirmed that the administration of BI 2536 led to significant decrease of PLK1 and Mcl-1 protein expression levels in dose-dependent and time-dependent manners. Furthermore, BI 2536-induced apoptosis in the Osteosarcoma Cell lines was shown by poly (ADP-ribose) polymerase cleavage and caspase assay. Finally, in mouse Osteosarcoma xenografts, BI 2536-treated mice had significantly smaller tumors compared with the control mice. These findings offer evidence of the potential role for targeting PLK1 in Osteosarcoma therapy.
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cyclin g associated kinase is necessary for Osteosarcoma Cell proliferation and receptor trafficking
Molecular Cancer Therapeutics, 2010Co-Authors: Michiro Susa, Edwin Choy, Henry J Mankin, Francis J Hornicek, Joseph H Schwab, Xianzhe Liu, Zhenfeng DuanAbstract:Osteosarcoma is the most frequent primary malignant bone tumor among the children. The advent of neoadjuvant chemotherapy significantly improved the prognosis of patients with Osteosarcoma in the 1980s, but it has since plateaued in the past decades. Recently, one of the most researched areas in sarcoma treatment is tyrosine kinases. Here, we describe research on a serine/threonine kinase, cyclin G-associated kinase (GAK), which has not been reported in Osteosarcoma previously. In this study, a lentiviral based human shRNA library was utilized to screen for kinases in KHOS and U-2OS Osteosarcoma Cells. The expression of GAK was examined in Osteosarcoma and the effect on Cell proliferation was analyzed by GAK siRNA knockdown. The level of GAK expression and its correlation to prognosis was analyzed in Osteosarcoma tissue microarray. The effect of GAK depletion on insulin-like growth factor and epidermal growth factor receptor-mediated signal transduction was analyzed by Western blot. We observed that GAK was overexpressed in both Osteosarcoma Cell lines and tissue samples when compared with human osteoblasts. GAK knockdown by siRNA decreased Cell proliferation in both drug-sensitive and multidrug-resistant Osteosarcoma Cell lines. Immunohistochemistry of Osteosarcoma tissue microarray revealed that overexpression of GAK was associated with poor prognosis. Finally, knockdown of GAK resulted in alterations of receptor trafficking and several downstream proteins. In conclusion, our results suggest that Osteosarcoma Cell proliferation and survival are dependent on GAK. These findings may lead to the development of new therapeutic options for Osteosarcoma.
