The Experts below are selected from a list of 1044 Experts worldwide ranked by ideXlab platform
Lee M Ellis - One of the best experts on this subject based on the ideXlab platform.
-
Intracrine vegf signalling mediates colorectal cancer cell migration and invasion
British Journal of Cancer, 2017Co-Authors: Rajat Bhattacharya, Fan Fan, Rui Wang, Ling Xia, Delphine R Boulbes, Lee M EllisAbstract:Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) are key regulators of angiogenesis, affecting endothelial cell survival and function. However, the effect of VEGF-VEGFR signalling on tumour cell function is not well understood. Our previous studies in colorectal cancer (CRC) cells have demonstrated an Intracrine VEGF/VEGFR1 signalling mechanism that mediates CRC cell survival and chemo-sensitivity. Since extracellular VEGF signalling regulates migration of endothelial cells and various tumour cells, we attempted to determine whether Intracrine VEGF signalling affects CRC cell motility. Migration and invasion of CRC cells, with and without VEGF or VEGFR1 depletion, were assayed using transwell migration chambers. Changes in cell morphology, epithelial-mesenchymal transition (EMT) markers, and markers of cell motility were assessed by immunostaining and western blot. Depletion of intracellular VEGF and VEGFR1 in multiple CRC cell lines led to strong inhibition of migration and invasion of CRC cells. Except for Twist, there were no significant differences in markers of EMT between control and VEGF/VEGFR1-depleted CRC cells. However, VEGF/VEGFR1-depleted CRC cells demonstrated a significant reduction in levels of phosphorylated focal adhesion kinase and its upstream regulators pcMET and pEGFR. Inhibition of Intracrine VEGF signalling strongly inhibits CRC cell migration and invasion by regulating proteins involved in cell motility.
-
abstract 3255 inhibition of Intracrine vegf signaling prevents colorectal cancer cell migration and invasion
Cancer Research, 2016Co-Authors: Rajat Bhattacharya, Fan Fan, Rui Wang, Ling Xia, Delphine R Boulbes, Lee M EllisAbstract:Introduction: Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and vascular function. The mechanisms of VEGF signaling in angiogenesis have been extensively studied. However, its effects on tumor cell function remain to be elucidated. Our studies on depletion of VEGF by somatic knockout of the VEGF gene or by siRNA in human colorectal cancer (CRC) cell lines have demonstrated that loss of VEGF expression led to significantly decreased cell growth, increased apoptosis, and enhanced chemo-sensitivity of CRC cells through an Intracrine signaling mechanism. These Intracrine effects were mediated through VEGF by regulation of the activity of multiple receptor tyrosine kinases (e.g. EGFR, cMET) and downstream AKT signaling. Similar effects were observed by depletion of VEGF receptor 1 (VEGFR1), supporting the role of a novel intracellular VEGF-VEGFR1 complex in CRC cell survival. Since VEGF signaling has been shown to effect endothelial and tumor cell migration, we attempted to determine if inhibition of Intracrine VEGF signaling affected CRC cell motility. Methods: Migration and invasion of CRC cells, with and without VEGF depletion, were assayed using Boyden chambers and a serum gradient. Changes in cell morphology and epithelial to mesenchymal transition (EMT) markers and markers of cell motility were assessed by microscopy, immunostaining, and western blot analyses. Results: Depletion of VEGF by siRNAs in multiple CRC cell lines led to a very strong inhibition of migration and invasion of CRC cells. Such inhibition was not observed when CRC cells were treated with bevacizumab to inhibit paracrine or autocrine signaling. Further examination revealed no significant changes in cell morphology. Other than Twist, there were no significant differences between specific markers of EMT indicating that differences in migration and invasion were not due to classic alterations in EMT. However, significant changes in activation of mediators of cell motility were observed. VEGF depleted CRC cells demonstrated significantly lower levels of phosphorylated focal adhesion kinase (p-FAK) compared to cells with normal VEGF expression. Analyses of upstream regulators indicated strong reduction in either p-cMET or p-SRC depending on cell type. Conclusions: Inhibition of Intracrine VEGF signaling strongly inhibits CRC cell migration and invasion by regulating proteins involved in cell motility. Citation Format: Rajat Bhattacharya, Ling Xia, Fan Fan, Rui Wang, Delphine Boulbes, Xiang-Cang Ye, Lee Ellis. Inhibition of Intracrine VEGF signaling prevents colorectal cancer cell migration and invasion. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3255.
-
Intracrine vegf signaling mediates the activity of prosurvival pathways in human colorectal cancer cells
Cancer Research, 2016Co-Authors: Rajat Bhattacharya, Fan Fan, Rui Wang, Delphine R Boulbes, Xia Ling, Madonna Mcmanus, Lee M EllisAbstract:The effects of vascular endothelial growth factor-A (VEGF-A/VEGF) and its receptors on endothelial cells function have been studied extensively, but their effects on tumor cells are less well defined. Studies of human colorectal cancer cells where the VEGF gene has been deleted suggest an intracellular role of VEGF as a cell survival factor. In this study, we investigated the role of Intracrine VEGF signaling in colorectal cancer cell survival. In human colorectal cancer cells, RNAi-mediated depletion of VEGF decreased cell survival and enhanced sensitivity to chemotherapy. Unbiased reverse phase protein array studies and subsequent validation experiments indicated that impaired cell survival was a consequence of disrupted AKT and ERK1/2 (MAPK3/1) signaling, as evidenced by reduced phosphorylation. Inhibition of paracrine or autocrine VEGF signaling had no effect on phospho-AKT or phospho-ERK1/2 levels, indicating that VEGF mediates cell survival via an intracellular mechanism. Notably, RNAi-mediated depletion of VEGF receptor VEGFR1/FLT1 replicated the effects of VEGF depletion on phospho-AKT and phospho-ERK1/2 levels. Together, these studies show how VEGF functions as an Intracrine survival factor in colorectal cancer cells, demonstrating its distinct role in colorectal cancer cell survival. Cancer Res; 76(10); 3014-24. ©2016 AACR.
-
abstract 375 role of Intracrine vascular endothelial growth factor vegf signaling in colorectal cancer cell survival and metastasis
Cancer Research, 2013Co-Authors: Rajat Bhattacharya, Fan Fan, Shaija Samuel, Ganiraju C Manyam, Veera Baladandayuthapani, Lee M EllisAbstract:Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and vascular function, and it9s role in biology are thought to be well understood. Although the effects of VEGF on angiogenesis, i.e. on endothelial cells, have been extensively studied, its effects on tumor cell function remain to be clearly elucidated. Our laboratory has demonstrated the VEGF receptors are present and active on colorectal cancer (CRC) cells. Recently we have studied the phenotypic changes in human CRC cells to determine the role of autocrine/Intracrine VEGF signaling on tumor cell function. Using cell lines with somatic knockout of the VEGF gene we have been able to show that loss of VEGF expression led to significantly decreased cell growth and increased spontaneous apoptosis in CRC cells. Depletion of VEGF also increased the in vitro sensitivity of cells to the cytotoxic effects of the chemotherapeutic agent 5-fluorouracil. Importantly, these effects are not mediated in an autocrine or paracrine fashion, as neutralization of extracellular VEGF with a monoclonal antibody, or inhibition of kinase activity with small molecule inhibitors had no effect on CRC cell survival. These studies support a novel role for VEGF in cell survival as an Intracrine factor. In our attempt to characterize the molecular mechanisms responsible for the Intracrine pro-survival role of VEGF, we have performed gene microarray analyses on a pair of CRC cells with and without expression of VEGF. These studies show a clear difference in expression patterns of genes between cells that produce or lack VEGF, but surprisingly find no significant changes in gene expression when VEGF function is inhibited by functional antibodies (Bevacizumab). Our preliminary analyses of the gene expression profiles indicate that CRC cells lacking VEGF have increased levels of multiple receptor tyrosine kinases. In other biochemical assays, we also find that cells lacking VEGF have increased activation of survival and proliferation pathways compared to normal cells. Based on our data, we hypothesize that loss of VEGF may induce activation of other survival pathways that compensate for depletion of VEGF. Our microarray studies also indicate significant increases in a factor that has been implicated in increased metastasis in breast and lung cancer. This factor may be responsible for the increased migration and invasion of CRC cells lacking VEGF observed in vitro. Future studies will elucidate the exact role of VEGF in tumor cell survival and metastasis. Citation Format: Rajat Bhattacharya, Shaija Samuel, Fan Fan, Ganiraju Manyam, Veera Baladandayuthapani, Lee Ellis. Role of Intracrine vascular endothelial growth factor (VEGF) signaling in colorectal cancer cell survival and metastasis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 375. doi:10.1158/1538-7445.AM2013-375
Artavazd Tadevosyan - One of the best experts on this subject based on the ideXlab platform.
-
intracellular angiotensin ii interacts with nuclear angiotensin receptors in cardiac fibroblasts and regulates rna synthesis cell proliferation and collagen secretion
Journal of the American Heart Association, 2017Co-Authors: Artavazd Tadevosyan, Clemence Merlen, Bruce G Allen, Jiening Xiao, Sirirat Surinkaew, Patrice Naud, Masahide Harada, David Chatenet, Alain FournierAbstract:BackgroundCardiac fibroblasts play important functional and pathophysiological roles. Intracellular (“Intracrine”) angiotensin‐II (Ang‐II) signaling regulates intercellular communication, excitabil...
-
photoreleasable ligands to study Intracrine angiotensin ii signalling
The Journal of Physiology, 2015Co-Authors: Louis Villeneuve, Artavazd Tadevosyan, Myriam Letourneau, Benjamin Folch, Nicolas Doucet, Aida M MamarbachiAbstract:KEY POINTS: The renin-angiotensin system plays a key role in cardiovascular physiology and its overactivation has been implicated in the pathogenesis of several major cardiovascular diseases. There is growing evidence that angiotensin II (Ang-II) may function as an intracellular peptide to activate intracellular/nuclear receptors and their downstream signalling effectors independently of cell surface receptors. Current methods used to study Intracrine Ang-II signalling are limited to indirect approaches because of a lack of selective intracellularly-acting probes. Here, we present novel photoreleasable Ang-II analogues used to probe intracellular actions with spatial and temporal precision. The photorelease of intracellular Ang-II causes nuclear and cytosolic calcium mobilization and initiates the de novo synthesis of RNA in cardiac cells, demonstrating the application of the method. ABSTRACT: Several lines of evidence suggest that intracellular angiotensin II (Ang-II) contributes to the regulation of cardiac contractility, renal salt reabsorption, vascular tone and metabolism; however, work on Intracrine Ang-II signalling has been limited to indirect approaches because of a lack of selective intracellularly-acting probes. Here, we aimed to synthesize and characterize cell-permeant Ang-II analogues that are inactive without uncaging, but release active Ang-II upon exposure to a flash of UV-light, and act as novel tools for use in the study of Intracrine Ang-II physiology. We prepared three novel caged Ang-II analogues, [Tyr(DMNB)(4)]Ang-II, Ang-II-ODMNB and [Tyr(DMNB)(4)]Ang-II-ODMNB, based upon the incorporation of the photolabile moiety 4,5-dimethoxy-2-nitrobenzyl (DMNB). Compared to Ang-II, the caged Ang-II analogues showed 2-3 orders of magnitude reduced affinity toward both angiotensin type-1 (AT1R) and type-2 (AT2R) receptors in competition binding assays, and greatly-reduced potency in contraction assays of rat thoracic aorta. After receiving UV-irradiation, all three caged Ang-II analogues released Ang-II and potently induced the contraction of rat thoracic aorta. [Tyr(DMNB)(4)]Ang-II showed the most rapid photolysis upon UV-irradiation and was the focus of subsequent characterization. Whereas Ang-II and photolysed [Tyr(DMNB)(4)]Ang-II increased ERK1/2 phosphorylation (via AT1R) and cGMP production (AT2R), caged [Tyr(DMNB)(4)]Ang-II did not. Cellular uptake of [Tyr(DMNB)(4)]Ang-II was 4-fold greater than that of Ang-II and significantly greater than uptake driven by the positive-control HIV TAT(48-60) peptide. Intracellular photolysis of [Tyr(DMNB)(4)]Ang-II induced an increase in nucleoplasmic Ca(2+) ([Ca(2+)]n), and initiated 18S rRNA and nuclear factor kappa B mRNA synthesis in adult cardiac cells. We conclude that caged Ang-II analogues represent powerful new tools for use in the selective study of Intracrine signalling via Ang-II.
-
abstract 13203 novel photoreleasable caged angiotensin ii analogs to study Intracrine pharmacology in intact cells
Circulation, 2013Co-Authors: Artavazd Tadevosyan, Louis Villeneuve, Bruce G Allen, David Chatenet, Alain Fournier, Myriam Letourneau, Benjamin Folch, Nicolas Doucet, Terence E Hebert, Stanley NattelAbstract:Background: Angiotensin type 1 (AT1R) and type 2 (AT2R) receptors on intracellular membranes might play an important role in cardiac remodeling, but the importance of intracellular “Intracrine” sig...
Carlos M Ferrario - One of the best experts on this subject based on the ideXlab platform.
-
novel cardiac Intracrine mechanisms based on ang 1 12 chymase axis require a revision of therapeutic approaches in human heart disease
Current Hypertension Reports, 2017Co-Authors: Santiago Reyes, Jasmina Varagic, Sarfaraz Ahmad, Jessica L Voncannon, Neal D Kon, Hao Wang, Leanne Groban, Che Ping Cheng, Louis J Dellitalia, Carlos M FerrarioAbstract:Drugs targeting the renin-angiotensin system (RAS), namely angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, are the most commonly prescribed drugs for patients with or at risk for cardiovascular events. However, new treatment strategies aimed at mitigating the rise of the heart failure pandemic are warranted because clinical trials show that RAS blockers have limited benefits in halting disease progression. The main goal of this review is to put forward the concept of an Intracrine RAS signaling through the novel angiotensin-(1-12)/chymase axis as the main source of deleterious angiotensin II (Ang II) in cardiac maladaptive remodeling leading to heart failure (HF). Expanding traditional knowledge, Ang II can be produced in tissues independently from the circulatory renin-angiotensin system. In the heart, angiotensin-(1-12) [Ang-(1-12)], a recently discovered derivative of angiotensinogen, is a precursor of Ang II, and chymase rather than ACE is the main enzyme contributing to the direct production of Ang II from Ang-(1-12). The Ang-(1-12)/chymase axis is an independent Intracrine pathway accounting for the trophic, contractile, and pro-arrhythmic Ang II actions in the human heart. Ang-(1-12) expression and chymase activity have been found elevated in the left atrial appendage of heart disease subjects, suggesting a pivotal role of this axis in the progression of HF. Recent meta-analysis of large clinical trials on the use of ACE inhibitors and angiotensin receptor blockers in cardiovascular disease has demonstrated an imbalance between patients that significantly benefit from these therapeutic agents and those that remain at risk for heart disease progression. Looking to find an explanation, detailed investigation on the RAS has unveiled a previously unrecognized complexity of substrates and enzymes in tissues ultimately associated with the production of Ang II that may explain the shortcomings of ACE inhibition and angiotensin receptor blockade. Discovery of the Ang-(1-12)/chymase axis in human hearts, capable of producing Ang II independently from the circulatory RAS, has led to the notion that a tissue-delimited RAS signaling in an Intracrine fashion may account for the deleterious effects of Ang II in the heart, contributing to the transition from maladaptive cardiac remodeling to heart failure. Targeting intracellular RAS signaling may improve current therapies aimed at reducing the burden of heart failure.
-
novel cardiac Intracrine mechanisms based on ang 1 12 chymase axis require a revision of therapeutic approaches in human heart disease
Current Hypertension Reports, 2017Co-Authors: Santiago Reyes, Jasmina Varagic, Sarfaraz Ahmad, Jessica L Voncannon, Neal D Kon, Hao Wang, Leanne Groban, Che Ping Cheng, Louis J Dellitalia, Carlos M FerrarioAbstract:Purpose of the Review Drugs targeting the renin-angiotensin system (RAS), namely angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, are the most commonly prescribed drugs for patients with or at risk for cardiovascular events. However, new treatment strategies aimed at mitigating the rise of the heart failure pandemic are warranted because clinical trials show that RAS blockers have limited benefits in halting disease progression. The main goal of this review is to put forward the concept of an Intracrine RAS signaling through the novel angiotensin-(1-12)/chymase axis as the main source of deleterious angiotensin II (Ang II) in cardiac maladaptive remodeling leading to heart failure (HF).
A Jan H Danser - One of the best experts on this subject based on the ideXlab platform.
-
cardiac angiotensin ii an Intracrine hormone
American Journal of Hypertension, 2002Co-Authors: Martin P Schuijt, A Jan H DanserAbstract:The beneficial effects of renin-angiotensin system blockers on cardiac structure and function are usually explained based on the capacity of these drugs to interfere with angiotensin II at cardiac tissue sites. This review addresses to what degree cardiac angiotensin II generation occurs independently of the circulating renin-angiotensin system, and in particular tries to unravel where such generation might take place, taking into consideration that many reports suggest that angiotensin II is an Intracrine hormone (ie, a hormone that is synthesized and acts intracellularly). It concludes that angiotensin II generation in the heart depends on circulating (ie, kidney-derived) renin, and occurs in interstitial fluid and possibly, in view of the recent discovery of renin-binding sites, on the cell surface of cardiac cells. Intracellular angiotensin II generation is unlikely to occur, in particular because angiotensinogen is not available in the cytosol.
-
angiotensin ii and the heart on the Intracrine renin angiotensin system
Hypertension, 2000Co-Authors: Walmor C De Mello, A Jan H DanserAbstract:-The active end product of the renin-angiotensin system, angiotensin II (Ang II), through the activation of specific Ang II receptors, regulates cardiac contractility, cell coupling, and impulse propagation and is involved in cardiac remodeling, growth, and apoptosis. We review these subjects, as well as the second messengers that are involved, and the synthesis of Ang II in the heart under normal and pathological conditions. Finally, we discuss the possibility that there is an Intracrine renin-angiotensin system in the heart that plays a role in the control of cell communication and inward Ca(2+) current.
Rajat Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
-
Intracrine vegf signalling mediates colorectal cancer cell migration and invasion
British Journal of Cancer, 2017Co-Authors: Rajat Bhattacharya, Fan Fan, Rui Wang, Ling Xia, Delphine R Boulbes, Lee M EllisAbstract:Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) are key regulators of angiogenesis, affecting endothelial cell survival and function. However, the effect of VEGF-VEGFR signalling on tumour cell function is not well understood. Our previous studies in colorectal cancer (CRC) cells have demonstrated an Intracrine VEGF/VEGFR1 signalling mechanism that mediates CRC cell survival and chemo-sensitivity. Since extracellular VEGF signalling regulates migration of endothelial cells and various tumour cells, we attempted to determine whether Intracrine VEGF signalling affects CRC cell motility. Migration and invasion of CRC cells, with and without VEGF or VEGFR1 depletion, were assayed using transwell migration chambers. Changes in cell morphology, epithelial-mesenchymal transition (EMT) markers, and markers of cell motility were assessed by immunostaining and western blot. Depletion of intracellular VEGF and VEGFR1 in multiple CRC cell lines led to strong inhibition of migration and invasion of CRC cells. Except for Twist, there were no significant differences in markers of EMT between control and VEGF/VEGFR1-depleted CRC cells. However, VEGF/VEGFR1-depleted CRC cells demonstrated a significant reduction in levels of phosphorylated focal adhesion kinase and its upstream regulators pcMET and pEGFR. Inhibition of Intracrine VEGF signalling strongly inhibits CRC cell migration and invasion by regulating proteins involved in cell motility.
-
abstract 3255 inhibition of Intracrine vegf signaling prevents colorectal cancer cell migration and invasion
Cancer Research, 2016Co-Authors: Rajat Bhattacharya, Fan Fan, Rui Wang, Ling Xia, Delphine R Boulbes, Lee M EllisAbstract:Introduction: Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and vascular function. The mechanisms of VEGF signaling in angiogenesis have been extensively studied. However, its effects on tumor cell function remain to be elucidated. Our studies on depletion of VEGF by somatic knockout of the VEGF gene or by siRNA in human colorectal cancer (CRC) cell lines have demonstrated that loss of VEGF expression led to significantly decreased cell growth, increased apoptosis, and enhanced chemo-sensitivity of CRC cells through an Intracrine signaling mechanism. These Intracrine effects were mediated through VEGF by regulation of the activity of multiple receptor tyrosine kinases (e.g. EGFR, cMET) and downstream AKT signaling. Similar effects were observed by depletion of VEGF receptor 1 (VEGFR1), supporting the role of a novel intracellular VEGF-VEGFR1 complex in CRC cell survival. Since VEGF signaling has been shown to effect endothelial and tumor cell migration, we attempted to determine if inhibition of Intracrine VEGF signaling affected CRC cell motility. Methods: Migration and invasion of CRC cells, with and without VEGF depletion, were assayed using Boyden chambers and a serum gradient. Changes in cell morphology and epithelial to mesenchymal transition (EMT) markers and markers of cell motility were assessed by microscopy, immunostaining, and western blot analyses. Results: Depletion of VEGF by siRNAs in multiple CRC cell lines led to a very strong inhibition of migration and invasion of CRC cells. Such inhibition was not observed when CRC cells were treated with bevacizumab to inhibit paracrine or autocrine signaling. Further examination revealed no significant changes in cell morphology. Other than Twist, there were no significant differences between specific markers of EMT indicating that differences in migration and invasion were not due to classic alterations in EMT. However, significant changes in activation of mediators of cell motility were observed. VEGF depleted CRC cells demonstrated significantly lower levels of phosphorylated focal adhesion kinase (p-FAK) compared to cells with normal VEGF expression. Analyses of upstream regulators indicated strong reduction in either p-cMET or p-SRC depending on cell type. Conclusions: Inhibition of Intracrine VEGF signaling strongly inhibits CRC cell migration and invasion by regulating proteins involved in cell motility. Citation Format: Rajat Bhattacharya, Ling Xia, Fan Fan, Rui Wang, Delphine Boulbes, Xiang-Cang Ye, Lee Ellis. Inhibition of Intracrine VEGF signaling prevents colorectal cancer cell migration and invasion. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3255.
-
Intracrine vegf signaling mediates the activity of prosurvival pathways in human colorectal cancer cells
Cancer Research, 2016Co-Authors: Rajat Bhattacharya, Fan Fan, Rui Wang, Delphine R Boulbes, Xia Ling, Madonna Mcmanus, Lee M EllisAbstract:The effects of vascular endothelial growth factor-A (VEGF-A/VEGF) and its receptors on endothelial cells function have been studied extensively, but their effects on tumor cells are less well defined. Studies of human colorectal cancer cells where the VEGF gene has been deleted suggest an intracellular role of VEGF as a cell survival factor. In this study, we investigated the role of Intracrine VEGF signaling in colorectal cancer cell survival. In human colorectal cancer cells, RNAi-mediated depletion of VEGF decreased cell survival and enhanced sensitivity to chemotherapy. Unbiased reverse phase protein array studies and subsequent validation experiments indicated that impaired cell survival was a consequence of disrupted AKT and ERK1/2 (MAPK3/1) signaling, as evidenced by reduced phosphorylation. Inhibition of paracrine or autocrine VEGF signaling had no effect on phospho-AKT or phospho-ERK1/2 levels, indicating that VEGF mediates cell survival via an intracellular mechanism. Notably, RNAi-mediated depletion of VEGF receptor VEGFR1/FLT1 replicated the effects of VEGF depletion on phospho-AKT and phospho-ERK1/2 levels. Together, these studies show how VEGF functions as an Intracrine survival factor in colorectal cancer cells, demonstrating its distinct role in colorectal cancer cell survival. Cancer Res; 76(10); 3014-24. ©2016 AACR.
-
abstract 375 role of Intracrine vascular endothelial growth factor vegf signaling in colorectal cancer cell survival and metastasis
Cancer Research, 2013Co-Authors: Rajat Bhattacharya, Fan Fan, Shaija Samuel, Ganiraju C Manyam, Veera Baladandayuthapani, Lee M EllisAbstract:Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and vascular function, and it9s role in biology are thought to be well understood. Although the effects of VEGF on angiogenesis, i.e. on endothelial cells, have been extensively studied, its effects on tumor cell function remain to be clearly elucidated. Our laboratory has demonstrated the VEGF receptors are present and active on colorectal cancer (CRC) cells. Recently we have studied the phenotypic changes in human CRC cells to determine the role of autocrine/Intracrine VEGF signaling on tumor cell function. Using cell lines with somatic knockout of the VEGF gene we have been able to show that loss of VEGF expression led to significantly decreased cell growth and increased spontaneous apoptosis in CRC cells. Depletion of VEGF also increased the in vitro sensitivity of cells to the cytotoxic effects of the chemotherapeutic agent 5-fluorouracil. Importantly, these effects are not mediated in an autocrine or paracrine fashion, as neutralization of extracellular VEGF with a monoclonal antibody, or inhibition of kinase activity with small molecule inhibitors had no effect on CRC cell survival. These studies support a novel role for VEGF in cell survival as an Intracrine factor. In our attempt to characterize the molecular mechanisms responsible for the Intracrine pro-survival role of VEGF, we have performed gene microarray analyses on a pair of CRC cells with and without expression of VEGF. These studies show a clear difference in expression patterns of genes between cells that produce or lack VEGF, but surprisingly find no significant changes in gene expression when VEGF function is inhibited by functional antibodies (Bevacizumab). Our preliminary analyses of the gene expression profiles indicate that CRC cells lacking VEGF have increased levels of multiple receptor tyrosine kinases. In other biochemical assays, we also find that cells lacking VEGF have increased activation of survival and proliferation pathways compared to normal cells. Based on our data, we hypothesize that loss of VEGF may induce activation of other survival pathways that compensate for depletion of VEGF. Our microarray studies also indicate significant increases in a factor that has been implicated in increased metastasis in breast and lung cancer. This factor may be responsible for the increased migration and invasion of CRC cells lacking VEGF observed in vitro. Future studies will elucidate the exact role of VEGF in tumor cell survival and metastasis. Citation Format: Rajat Bhattacharya, Shaija Samuel, Fan Fan, Ganiraju Manyam, Veera Baladandayuthapani, Lee Ellis. Role of Intracrine vascular endothelial growth factor (VEGF) signaling in colorectal cancer cell survival and metastasis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 375. doi:10.1158/1538-7445.AM2013-375