The Experts below are selected from a list of 9591 Experts worldwide ranked by ideXlab platform
Stanley Lipkowitz - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Open Access
2016Co-Authors: Sireesha V Garimella, Kristie Gehlhaus, Jennifer L Dine, Jason J Pitt, Sirisha Chakka, Marion M Nau, Natasha J Caplen, Stanley LipkowitzAbstract:Identification of novel molecular regulators of tumor necrosis factor-related apoptosis-inducing optosis in breast cancer different breast cancer subtypes and sensitivities to TRAIL validated and extended these findings. Further, we Garimella et al. Breast Cancer Research 2014, 16:R4
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Abstract 15: gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2015Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Daniel Letwin, Stanley LipkowitzAbstract:Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA TNF-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in transformed cells by activating the extrinsic apoptotic pathway via its cognate receptors on the cell surface, TRAIL receptor 1 and TRAIL receptor 2. Triple negative breast cancer (TNBC) cells (so-called because TNBC lacks estrogen and progesterone receptor expression and Her-2 amplification) have been found to be sensitive to TRAIL while breast cancer cells of other subtypes of disease remain relatively resistant. Unfortunately, the mechanisms that govern sensitivity to TRAIL are not yet understood. The identification and characterization of novel regulators of the TRAIL pathway would provide new insights into the mechanisms that regulate TRAIL and potentially provide therapeutically exploitable molecular targets for the enhancement of TRAIL-based cancer treatments. In order to identify candidate regulators of the TRAIL pathway, our lab carried out a high-throughput RNAi-mediated screen of ∼1300 genes using the TNBC cell line MB231. One hundred fifty candidate regulators were identified. The RING finger ubiquitin ligase gp78 (also known as AMFR) was identified as a candidate negative regulator of TRAIL sensitivity. gp78 is an endoplasmic reticulum (ER)-residing protein that helps facilitate the retrotranslocation of substrates across the ER membrane into the cytosol during ER-associated protein degradation. This process is critical to maintaining cellular homeostasis by promoting the proteasomal elimination of misfolded proteins and is integral to cell survival. Interestingly, gp78 has previously been found to promote metastasis in a mouse sarcoma model, and in this study, we have further characterized gp78 as an inhibitor of apoptosis. The initial findings from the RNAi screen were confirmed by carrying out siRNA-mediated knockdown of gp78 in MB231 cells. The cells with inhibited gp78 expression were found to be significantly sensitive to TRAIL-induced caspase-3/7 activity and loss in viability. Knockdown of gp78 using in total 11 independent siRNAs demonstrated a reduction in gp78 expression is associated with TRAIL sensitization. Furthermore, pan-caspase inhibition with the pharmacologic inhibitor ZVAD-FMK completely abrogated sensitization to TRAIL with gp78 knockdown, demonstrating that loss in viability is caspase dependent. These results were further characterized by knocking down gp78 alone or along with one of the initiator caspases, 2, 8, 9, or 10. Loss of the initiator caspases 2 and 8 reduced sensitivity to TRAIL with gp78 knockdown, suggesting that pathways involved in the activation of these caspases in particular may be conferring sensitivity to TRAIL. In summary, our lab has identified and characterized gp78 as a regulator of TRAIL sensitivity through a caspase-mediated mechanism in breast cancer cells. Continued study is warranted to fully elucidate the molecular mechanisms by which gp78 inhibits TRAIL-induced apoptosis. Citation Format: Jennifer L. Dine, Sireesha V. Garimella, Kristie Gehlhaus, Magda Grandin, Daniel Letwin, Natasha Caplen, Stanley Lipkowitz. gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 15. doi:10.1158/1538-7445.AM2015-15
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Abstract 5124: Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2014Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Stanley LipkowitzAbstract:TNF-related apoptosis inducing ligand (TRAIL) is a member of the tumor necrosis factor super family and can induce apoptotic cell death upon binding to its cognate receptors, TRAIL Receptor 1 (TRAIL-R1) and TRAIL Receptor 2 (TRAIL-R2). TRAIL has been found to induce selectively cell death in triple negative breast cancer (TNBC) cell lines (so called because the breast cancer cells lack estrogen and progesterone receptor expression and Her-2 amplification). Other subtypes of breast cancer are relatively resistant to TRAIL-induced apoptosis. However, the mechanisms that underlie the sensitivity of TNBCs to TRAIL-induced apoptosis are not yet understood. To identify regulators of TRAIL-induced apoptosis in the TNBC/mesenchymal cell line MB231, an siRNA screen of the kinome, phosphatome, and other potential regulators (∼1,300 genes) of the TRAIL pathway was carried out to measure the effects of loss of function of these genes on TRAIL-induced caspase-3/7 activation, capase-8 activation, and cell death. One hundred fifty negative regulators of the TRAIL pathway were identified, including 83 kinases, 4 phosphatases, and 63 non-kinases. The identified regulators were involved in diverse cell processes, including apoptosis, transcriptional regulation, growth factor receptor signaling, DNA repair, cell metabolism, and cell cycle regulation. Interestingly, no positive regulators were identified. A subset of the 150 candidates were rescreened in MB231 and three additional cell lines representative of other subytpes of breast cancer, including MB468 (TNBC/basal), SKBR3 (Her-2 amplified), and T47D (estrogen receptor positive). Interestingly, the TNBC/basal cell line MB468 was sensitized to TRAIL-induced caspase-3/7 activation by all of the candidates, whereas T47D and SKBR3 were sensitized to TRAIL by only two and three of the candidates, respectively. These findings demonstrate that breast cancer cell lines are varyingly sensitized to the effects of TRAIL. The anti-apoptotic protein Bcl-xL and the tyrosine kinase Src were also identified as negative regulators of TRAIL-induced apoptosis. We have further shown that pharmacologic inhibition of Bcl-xL or Src sensitize a wide range of breast cancer cell lines to TRAIL-induced apoptosis. These findings lend further support to the screen. Overall, the siRNA screen has identified many regulators of TRAIL-induced apoptosis in the TNBC cell line MB231 and a smaller subset of regulators in breast cancer cell lines representative of other subtypes. These findings suggest targets for the rational development of combination therapy in breast cancer treatment. Citation Format: Jennifer Dine, Sireesha Garimella, Kristie Gehlhaus, Magda Grandin, Natasha Caplen, Stanley Lipkowitz. Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5124. doi:10.1158/1538-7445.AM2014-5124
Jennifer L Dine - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Open Access
2016Co-Authors: Sireesha V Garimella, Kristie Gehlhaus, Jennifer L Dine, Jason J Pitt, Sirisha Chakka, Marion M Nau, Natasha J Caplen, Stanley LipkowitzAbstract:Identification of novel molecular regulators of tumor necrosis factor-related apoptosis-inducing optosis in breast cancer different breast cancer subtypes and sensitivities to TRAIL validated and extended these findings. Further, we Garimella et al. Breast Cancer Research 2014, 16:R4
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Abstract 15: gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2015Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Daniel Letwin, Stanley LipkowitzAbstract:Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA TNF-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in transformed cells by activating the extrinsic apoptotic pathway via its cognate receptors on the cell surface, TRAIL receptor 1 and TRAIL receptor 2. Triple negative breast cancer (TNBC) cells (so-called because TNBC lacks estrogen and progesterone receptor expression and Her-2 amplification) have been found to be sensitive to TRAIL while breast cancer cells of other subtypes of disease remain relatively resistant. Unfortunately, the mechanisms that govern sensitivity to TRAIL are not yet understood. The identification and characterization of novel regulators of the TRAIL pathway would provide new insights into the mechanisms that regulate TRAIL and potentially provide therapeutically exploitable molecular targets for the enhancement of TRAIL-based cancer treatments. In order to identify candidate regulators of the TRAIL pathway, our lab carried out a high-throughput RNAi-mediated screen of ∼1300 genes using the TNBC cell line MB231. One hundred fifty candidate regulators were identified. The RING finger ubiquitin ligase gp78 (also known as AMFR) was identified as a candidate negative regulator of TRAIL sensitivity. gp78 is an endoplasmic reticulum (ER)-residing protein that helps facilitate the retrotranslocation of substrates across the ER membrane into the cytosol during ER-associated protein degradation. This process is critical to maintaining cellular homeostasis by promoting the proteasomal elimination of misfolded proteins and is integral to cell survival. Interestingly, gp78 has previously been found to promote metastasis in a mouse sarcoma model, and in this study, we have further characterized gp78 as an inhibitor of apoptosis. The initial findings from the RNAi screen were confirmed by carrying out siRNA-mediated knockdown of gp78 in MB231 cells. The cells with inhibited gp78 expression were found to be significantly sensitive to TRAIL-induced caspase-3/7 activity and loss in viability. Knockdown of gp78 using in total 11 independent siRNAs demonstrated a reduction in gp78 expression is associated with TRAIL sensitization. Furthermore, pan-caspase inhibition with the pharmacologic inhibitor ZVAD-FMK completely abrogated sensitization to TRAIL with gp78 knockdown, demonstrating that loss in viability is caspase dependent. These results were further characterized by knocking down gp78 alone or along with one of the initiator caspases, 2, 8, 9, or 10. Loss of the initiator caspases 2 and 8 reduced sensitivity to TRAIL with gp78 knockdown, suggesting that pathways involved in the activation of these caspases in particular may be conferring sensitivity to TRAIL. In summary, our lab has identified and characterized gp78 as a regulator of TRAIL sensitivity through a caspase-mediated mechanism in breast cancer cells. Continued study is warranted to fully elucidate the molecular mechanisms by which gp78 inhibits TRAIL-induced apoptosis. Citation Format: Jennifer L. Dine, Sireesha V. Garimella, Kristie Gehlhaus, Magda Grandin, Daniel Letwin, Natasha Caplen, Stanley Lipkowitz. gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 15. doi:10.1158/1538-7445.AM2015-15
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Abstract 5124: Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2014Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Stanley LipkowitzAbstract:TNF-related apoptosis inducing ligand (TRAIL) is a member of the tumor necrosis factor super family and can induce apoptotic cell death upon binding to its cognate receptors, TRAIL Receptor 1 (TRAIL-R1) and TRAIL Receptor 2 (TRAIL-R2). TRAIL has been found to induce selectively cell death in triple negative breast cancer (TNBC) cell lines (so called because the breast cancer cells lack estrogen and progesterone receptor expression and Her-2 amplification). Other subtypes of breast cancer are relatively resistant to TRAIL-induced apoptosis. However, the mechanisms that underlie the sensitivity of TNBCs to TRAIL-induced apoptosis are not yet understood. To identify regulators of TRAIL-induced apoptosis in the TNBC/mesenchymal cell line MB231, an siRNA screen of the kinome, phosphatome, and other potential regulators (∼1,300 genes) of the TRAIL pathway was carried out to measure the effects of loss of function of these genes on TRAIL-induced caspase-3/7 activation, capase-8 activation, and cell death. One hundred fifty negative regulators of the TRAIL pathway were identified, including 83 kinases, 4 phosphatases, and 63 non-kinases. The identified regulators were involved in diverse cell processes, including apoptosis, transcriptional regulation, growth factor receptor signaling, DNA repair, cell metabolism, and cell cycle regulation. Interestingly, no positive regulators were identified. A subset of the 150 candidates were rescreened in MB231 and three additional cell lines representative of other subytpes of breast cancer, including MB468 (TNBC/basal), SKBR3 (Her-2 amplified), and T47D (estrogen receptor positive). Interestingly, the TNBC/basal cell line MB468 was sensitized to TRAIL-induced caspase-3/7 activation by all of the candidates, whereas T47D and SKBR3 were sensitized to TRAIL by only two and three of the candidates, respectively. These findings demonstrate that breast cancer cell lines are varyingly sensitized to the effects of TRAIL. The anti-apoptotic protein Bcl-xL and the tyrosine kinase Src were also identified as negative regulators of TRAIL-induced apoptosis. We have further shown that pharmacologic inhibition of Bcl-xL or Src sensitize a wide range of breast cancer cell lines to TRAIL-induced apoptosis. These findings lend further support to the screen. Overall, the siRNA screen has identified many regulators of TRAIL-induced apoptosis in the TNBC cell line MB231 and a smaller subset of regulators in breast cancer cell lines representative of other subtypes. These findings suggest targets for the rational development of combination therapy in breast cancer treatment. Citation Format: Jennifer Dine, Sireesha Garimella, Kristie Gehlhaus, Magda Grandin, Natasha Caplen, Stanley Lipkowitz. Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5124. doi:10.1158/1538-7445.AM2014-5124
Suresh V. Garimella - One of the best experts on this subject based on the ideXlab platform.
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1 Saturated Flow Boiling Heat Transfer and Pressure Drop in Silicon Microchannel Arrays§
2016Co-Authors: Purdue E-pubs, Poh Seng Lee, S V. Garimella, Suresh V. GarimellaAbstract:additional information. Lee, Poh-Seng and Garimella, S V., "Saturated Flow Boiling Heat Transfer and Pressure Drop in Silicon Microchannel Arrays " (2008)
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A Comprehensive Flow Regime Map for Microchannel Flow Boiling with Quantitative Transition Criteria 1
2016Co-Authors: Purdue E-pubs, Tannaz Harirchian, S V. Garimella, Suresh V. GarimellaAbstract:additional information. Harirchian, Tannaz and Garimella, S V., "A Comprehensive Flow Regime Map for Microchannel Flow Boiling with Quantitativ
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Flow Visualization During Droplet Evaporation on Hydrophobic and Superhydrophobic Surfaces
Journal of Heat Transfer, 2014Co-Authors: Susmita Dash, Aditya Chandramohan, Suresh V. GarimellaAbstract:a.2 b.2 C.2 The flow behavior inside an evaporating droplet on a hydrophobic (initial contact angle ~120 deg) and superhydrophobic surface (initial contact angle ~ 150 deg) is studied using Particle Image Velocimetry (PIV). Water droplets (with initial volume ~ 3 μL) are considered with suspended fluorescent polystyrene particles for visualization. An axisymmetric counter-rotating vortex pair is observed in the vertical plane of the droplet as it evaporates on the hydrophobic surface. The flow direction is upwards along the vertical axis of the droplet signifying a buoyancy-induced flow field. A single-directional vortex structure occurs in the droplet evaporating on superhydrophobic surface. An image-correction algorithm based on the ray-tracing technique is employed to correct the distortion caused due to refraction of light at the surface of the droplet, and yield an accurate quantitative estimation of the velocity vectors. Centrally localized deposition of suspended particles observed for droplet evaporation on hydrophobic and superhydrophobic surfaces as opposed to the circumferential deposition seen in the case of hydrophilic surfaces is explained in terms of the observed convection flow characteristics. Flow Visualization During Droplet Evaporation on Hydrophobic and Superhydrophobic Surfaces Susmita Dash, Aditya Chandramohan, and Suresh V. Garimella NSF Cooling Technologies Research Center School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA Center-plane illuminated by laser light sheet
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Bridgman Crystal Growth of an Alloy with Thermosolutal Convection Under Microgravity Conditions
2013Co-Authors: James E. Simpson, Suresh V. Garimella, Henry C. De Groh, Reza AbbaschianAbstract:James E. Simpson, Suresh V. Garimella ISchool of Mechanical EngineeringPurdue UniversityWest Lafayette, Indiana 47907-1288Phone: (765) 494-5621; Fax: (765) 494-0539sureshg@ecn.purdue.eduHenry C. de Groh IIINASA Glenn Research CenterCleveland, Ohio 44135Reza AbbaschianDepartment of Materials Science and EngineeringUniversity of FloridaGainesville, Florida 32611ABSTRACTThe solidification of a dilute alloy (bismuth-tin) under Bridgman crystal growth conditions isinvestigated. Computations are performed in two dimensions with a uniform grid. The simulationincludes the species concentration, temperature and flow fields, as well as conduction in theampoule. Fully transient simulations have been performed, with no simplifying steady stateapproximations. Results are obtained under microgravity conditions for pure bismuth, and for Bi-0.1at.%Sn and Bi-l.0 at.%Sn alloys, and compared with experimental results obtained from crystalsgrown in the microgravity environment of space. For the Bi-l.0at.%Sn case the results indicate that asecondary convective cell, driven by solutal gradients, forms near the interface. The magnitude of thevelocities in this cell increases with time, causing increasing solute segregation at the solid/liquidinterface. The concentration-dependence of the melting temperature is incorporated in the model forthe Bi-l.0 at.%Sn alloy. Satisfactory correspondence is obtained between the predicted andexperimental results in terms of solute concentrations in the solidified crystal.§ Submitted for possible publication in ASME Journal of Heat Transfer, October 1998 and in revisedform, April 25, 2000¶ Associate Professor, author to whom correspondence should be addressed
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Development of a Particle Tracking-Based Measurement Technique to Map Three-Dimensional Interfaces between Transparent, Immiscible Fluids
2012Co-Authors: Purdue E-pubs, Suresh V. Garimella, Ncn Publications, Ravi S. PatelAbstract:Part of the Nanoscience and Nanotechnology Commons This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact epubs@purdue.edu for additional information. Patel, Ravi S. and Garimella, Suresh V., "Development of a Particle Tracking-Based Measurement Technique to Map Three
Magda Grandin - One of the best experts on this subject based on the ideXlab platform.
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Abstract 15: gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2015Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Daniel Letwin, Stanley LipkowitzAbstract:Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA TNF-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in transformed cells by activating the extrinsic apoptotic pathway via its cognate receptors on the cell surface, TRAIL receptor 1 and TRAIL receptor 2. Triple negative breast cancer (TNBC) cells (so-called because TNBC lacks estrogen and progesterone receptor expression and Her-2 amplification) have been found to be sensitive to TRAIL while breast cancer cells of other subtypes of disease remain relatively resistant. Unfortunately, the mechanisms that govern sensitivity to TRAIL are not yet understood. The identification and characterization of novel regulators of the TRAIL pathway would provide new insights into the mechanisms that regulate TRAIL and potentially provide therapeutically exploitable molecular targets for the enhancement of TRAIL-based cancer treatments. In order to identify candidate regulators of the TRAIL pathway, our lab carried out a high-throughput RNAi-mediated screen of ∼1300 genes using the TNBC cell line MB231. One hundred fifty candidate regulators were identified. The RING finger ubiquitin ligase gp78 (also known as AMFR) was identified as a candidate negative regulator of TRAIL sensitivity. gp78 is an endoplasmic reticulum (ER)-residing protein that helps facilitate the retrotranslocation of substrates across the ER membrane into the cytosol during ER-associated protein degradation. This process is critical to maintaining cellular homeostasis by promoting the proteasomal elimination of misfolded proteins and is integral to cell survival. Interestingly, gp78 has previously been found to promote metastasis in a mouse sarcoma model, and in this study, we have further characterized gp78 as an inhibitor of apoptosis. The initial findings from the RNAi screen were confirmed by carrying out siRNA-mediated knockdown of gp78 in MB231 cells. The cells with inhibited gp78 expression were found to be significantly sensitive to TRAIL-induced caspase-3/7 activity and loss in viability. Knockdown of gp78 using in total 11 independent siRNAs demonstrated a reduction in gp78 expression is associated with TRAIL sensitization. Furthermore, pan-caspase inhibition with the pharmacologic inhibitor ZVAD-FMK completely abrogated sensitization to TRAIL with gp78 knockdown, demonstrating that loss in viability is caspase dependent. These results were further characterized by knocking down gp78 alone or along with one of the initiator caspases, 2, 8, 9, or 10. Loss of the initiator caspases 2 and 8 reduced sensitivity to TRAIL with gp78 knockdown, suggesting that pathways involved in the activation of these caspases in particular may be conferring sensitivity to TRAIL. In summary, our lab has identified and characterized gp78 as a regulator of TRAIL sensitivity through a caspase-mediated mechanism in breast cancer cells. Continued study is warranted to fully elucidate the molecular mechanisms by which gp78 inhibits TRAIL-induced apoptosis. Citation Format: Jennifer L. Dine, Sireesha V. Garimella, Kristie Gehlhaus, Magda Grandin, Daniel Letwin, Natasha Caplen, Stanley Lipkowitz. gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 15. doi:10.1158/1538-7445.AM2015-15
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Abstract 5124: Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2014Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Stanley LipkowitzAbstract:TNF-related apoptosis inducing ligand (TRAIL) is a member of the tumor necrosis factor super family and can induce apoptotic cell death upon binding to its cognate receptors, TRAIL Receptor 1 (TRAIL-R1) and TRAIL Receptor 2 (TRAIL-R2). TRAIL has been found to induce selectively cell death in triple negative breast cancer (TNBC) cell lines (so called because the breast cancer cells lack estrogen and progesterone receptor expression and Her-2 amplification). Other subtypes of breast cancer are relatively resistant to TRAIL-induced apoptosis. However, the mechanisms that underlie the sensitivity of TNBCs to TRAIL-induced apoptosis are not yet understood. To identify regulators of TRAIL-induced apoptosis in the TNBC/mesenchymal cell line MB231, an siRNA screen of the kinome, phosphatome, and other potential regulators (∼1,300 genes) of the TRAIL pathway was carried out to measure the effects of loss of function of these genes on TRAIL-induced caspase-3/7 activation, capase-8 activation, and cell death. One hundred fifty negative regulators of the TRAIL pathway were identified, including 83 kinases, 4 phosphatases, and 63 non-kinases. The identified regulators were involved in diverse cell processes, including apoptosis, transcriptional regulation, growth factor receptor signaling, DNA repair, cell metabolism, and cell cycle regulation. Interestingly, no positive regulators were identified. A subset of the 150 candidates were rescreened in MB231 and three additional cell lines representative of other subytpes of breast cancer, including MB468 (TNBC/basal), SKBR3 (Her-2 amplified), and T47D (estrogen receptor positive). Interestingly, the TNBC/basal cell line MB468 was sensitized to TRAIL-induced caspase-3/7 activation by all of the candidates, whereas T47D and SKBR3 were sensitized to TRAIL by only two and three of the candidates, respectively. These findings demonstrate that breast cancer cell lines are varyingly sensitized to the effects of TRAIL. The anti-apoptotic protein Bcl-xL and the tyrosine kinase Src were also identified as negative regulators of TRAIL-induced apoptosis. We have further shown that pharmacologic inhibition of Bcl-xL or Src sensitize a wide range of breast cancer cell lines to TRAIL-induced apoptosis. These findings lend further support to the screen. Overall, the siRNA screen has identified many regulators of TRAIL-induced apoptosis in the TNBC cell line MB231 and a smaller subset of regulators in breast cancer cell lines representative of other subtypes. These findings suggest targets for the rational development of combination therapy in breast cancer treatment. Citation Format: Jennifer Dine, Sireesha Garimella, Kristie Gehlhaus, Magda Grandin, Natasha Caplen, Stanley Lipkowitz. Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5124. doi:10.1158/1538-7445.AM2014-5124
Kristie Gehlhaus - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Open Access
2016Co-Authors: Sireesha V Garimella, Kristie Gehlhaus, Jennifer L Dine, Jason J Pitt, Sirisha Chakka, Marion M Nau, Natasha J Caplen, Stanley LipkowitzAbstract:Identification of novel molecular regulators of tumor necrosis factor-related apoptosis-inducing optosis in breast cancer different breast cancer subtypes and sensitivities to TRAIL validated and extended these findings. Further, we Garimella et al. Breast Cancer Research 2014, 16:R4
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Abstract 15: gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2015Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Daniel Letwin, Stanley LipkowitzAbstract:Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA TNF-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in transformed cells by activating the extrinsic apoptotic pathway via its cognate receptors on the cell surface, TRAIL receptor 1 and TRAIL receptor 2. Triple negative breast cancer (TNBC) cells (so-called because TNBC lacks estrogen and progesterone receptor expression and Her-2 amplification) have been found to be sensitive to TRAIL while breast cancer cells of other subtypes of disease remain relatively resistant. Unfortunately, the mechanisms that govern sensitivity to TRAIL are not yet understood. The identification and characterization of novel regulators of the TRAIL pathway would provide new insights into the mechanisms that regulate TRAIL and potentially provide therapeutically exploitable molecular targets for the enhancement of TRAIL-based cancer treatments. In order to identify candidate regulators of the TRAIL pathway, our lab carried out a high-throughput RNAi-mediated screen of ∼1300 genes using the TNBC cell line MB231. One hundred fifty candidate regulators were identified. The RING finger ubiquitin ligase gp78 (also known as AMFR) was identified as a candidate negative regulator of TRAIL sensitivity. gp78 is an endoplasmic reticulum (ER)-residing protein that helps facilitate the retrotranslocation of substrates across the ER membrane into the cytosol during ER-associated protein degradation. This process is critical to maintaining cellular homeostasis by promoting the proteasomal elimination of misfolded proteins and is integral to cell survival. Interestingly, gp78 has previously been found to promote metastasis in a mouse sarcoma model, and in this study, we have further characterized gp78 as an inhibitor of apoptosis. The initial findings from the RNAi screen were confirmed by carrying out siRNA-mediated knockdown of gp78 in MB231 cells. The cells with inhibited gp78 expression were found to be significantly sensitive to TRAIL-induced caspase-3/7 activity and loss in viability. Knockdown of gp78 using in total 11 independent siRNAs demonstrated a reduction in gp78 expression is associated with TRAIL sensitization. Furthermore, pan-caspase inhibition with the pharmacologic inhibitor ZVAD-FMK completely abrogated sensitization to TRAIL with gp78 knockdown, demonstrating that loss in viability is caspase dependent. These results were further characterized by knocking down gp78 alone or along with one of the initiator caspases, 2, 8, 9, or 10. Loss of the initiator caspases 2 and 8 reduced sensitivity to TRAIL with gp78 knockdown, suggesting that pathways involved in the activation of these caspases in particular may be conferring sensitivity to TRAIL. In summary, our lab has identified and characterized gp78 as a regulator of TRAIL sensitivity through a caspase-mediated mechanism in breast cancer cells. Continued study is warranted to fully elucidate the molecular mechanisms by which gp78 inhibits TRAIL-induced apoptosis. Citation Format: Jennifer L. Dine, Sireesha V. Garimella, Kristie Gehlhaus, Magda Grandin, Daniel Letwin, Natasha Caplen, Stanley Lipkowitz. gp78 is a negative regulator of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 15. doi:10.1158/1538-7445.AM2015-15
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Abstract 5124: Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells
Molecular and Cellular Biology, 2014Co-Authors: Jennifer L Dine, Sireesha V Garimella, Kristie Gehlhaus, Natasha J Caplen, Magda Grandin, Stanley LipkowitzAbstract:TNF-related apoptosis inducing ligand (TRAIL) is a member of the tumor necrosis factor super family and can induce apoptotic cell death upon binding to its cognate receptors, TRAIL Receptor 1 (TRAIL-R1) and TRAIL Receptor 2 (TRAIL-R2). TRAIL has been found to induce selectively cell death in triple negative breast cancer (TNBC) cell lines (so called because the breast cancer cells lack estrogen and progesterone receptor expression and Her-2 amplification). Other subtypes of breast cancer are relatively resistant to TRAIL-induced apoptosis. However, the mechanisms that underlie the sensitivity of TNBCs to TRAIL-induced apoptosis are not yet understood. To identify regulators of TRAIL-induced apoptosis in the TNBC/mesenchymal cell line MB231, an siRNA screen of the kinome, phosphatome, and other potential regulators (∼1,300 genes) of the TRAIL pathway was carried out to measure the effects of loss of function of these genes on TRAIL-induced caspase-3/7 activation, capase-8 activation, and cell death. One hundred fifty negative regulators of the TRAIL pathway were identified, including 83 kinases, 4 phosphatases, and 63 non-kinases. The identified regulators were involved in diverse cell processes, including apoptosis, transcriptional regulation, growth factor receptor signaling, DNA repair, cell metabolism, and cell cycle regulation. Interestingly, no positive regulators were identified. A subset of the 150 candidates were rescreened in MB231 and three additional cell lines representative of other subytpes of breast cancer, including MB468 (TNBC/basal), SKBR3 (Her-2 amplified), and T47D (estrogen receptor positive). Interestingly, the TNBC/basal cell line MB468 was sensitized to TRAIL-induced caspase-3/7 activation by all of the candidates, whereas T47D and SKBR3 were sensitized to TRAIL by only two and three of the candidates, respectively. These findings demonstrate that breast cancer cell lines are varyingly sensitized to the effects of TRAIL. The anti-apoptotic protein Bcl-xL and the tyrosine kinase Src were also identified as negative regulators of TRAIL-induced apoptosis. We have further shown that pharmacologic inhibition of Bcl-xL or Src sensitize a wide range of breast cancer cell lines to TRAIL-induced apoptosis. These findings lend further support to the screen. Overall, the siRNA screen has identified many regulators of TRAIL-induced apoptosis in the TNBC cell line MB231 and a smaller subset of regulators in breast cancer cell lines representative of other subtypes. These findings suggest targets for the rational development of combination therapy in breast cancer treatment. Citation Format: Jennifer Dine, Sireesha Garimella, Kristie Gehlhaus, Magda Grandin, Natasha Caplen, Stanley Lipkowitz. Identification and characterization of novel regulators of TRAIL-induced apoptosis in breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5124. doi:10.1158/1538-7445.AM2014-5124
