BACKGROUND: The c-src protooncogene encodes a protein tyrosine kinase, pp60c-src, that is a mediator in many signal transduction pathways. One pathway in which pp60c-src protein tyrosine kinase activity is implicated involves regulation of vascular endothelial growth factor (VEGF), an angiogenic factor important to neovascularization of growing tumors. Recently we demonstrated that decreased activity of pp60c-src in colon tumor cells contributes to decreased expression of VEGF. This study examined the relationship between pp60c-src activation, cell density, and VEGF production in a colon tumor cell line. METHODS: Parental HT-29 colon adenocarcinoma cells and stable subclones created by transfection with c-src antisense and sense (control) expression vectors were plated under sparse (2 x 10(4) cells/cm2) and confluent (20 x 10(4) cells/cm2) conditions and grown for 36 hours. Protein and RNA were extracted from cells to determine pp60c-src levels, c-Src tyrosine kinase activity, and VEGF mRNA expression. RESULTS: The pp60c-src kinase activity of HT-29 cells and control sense-transfected clones grown under confluent conditions was increased threefold to fivefold compared with cells grown under sparse conditions. In contrast, the ability of confluent culture conditions to increase pp60c-src activity was blunted in antisense transfectants. By regression analysis, VEGF expression was found to vary directly with pp60c-src levels (r2 = 0.886). CONCLUSIONS: Cell density contributes to the regulation of c-src kinase activity and VEGF expression in HT-29 cells. When the steady-state level of pp60c-src is reduced in antisense transfectants, not only is the steady-state level of VEGF reduced, but the ability of confluence to stimulate pp60c-src activity and VEGF production is too. These data suggest that c-src may be an intermediary of both constitutive and inducible pathways for VEGF production in colon tumor cells.
BACKGROUND: The c-src protooncogene encodes a protein tyrosine kinase, pp60c-src, that is a mediator in many signal transduction pathways. One pathway in which pp60c-src protein tyrosine kinase activity is implicated involves regulation of vascular endothelial growth factor (VEGF), an angiogenic factor important to neovascularization of growing tumors. Recently we demonstrated that decreased activity of pp60c-src in colon tumor cells contributes to decreased expression of VEGF. This study examined the relationship between pp60c-src activation, cell density, and VEGF production in a colon tumor cell line. METHODS: Parental HT-29 colon adenocarcinoma cells and stable subclones created by transfection with c-src antisense and sense (control) expression vectors were plated under sparse (2 x 10(4) cells/cm2) and confluent (20 x 10(4) cells/cm2) conditions and grown for 36 hours. Protein and RNA were extracted from cells to determine pp60c-src levels, c-Src tyrosine kinase activity, and VEGF mRNA expression. RESULTS: The pp60c-src kinase activity of HT-29 cells and control sense-transfected clones grown under confluent conditions was increased threefold to fivefold compared with cells grown under sparse conditions. In contrast, the ability of confluent culture conditions to increase pp60c-src activity was blunted in antisense transfectants. By regression analysis, VEGF expression was found to vary directly with pp60c-src levels (r2 = 0.886). CONCLUSIONS: Cell density contributes to the regulation of c-src kinase activity and VEGF expression in HT-29 cells. When the steady-state level of pp60c-src is reduced in antisense transfectants, not only is the steady-state level of VEGF reduced, but the ability of confluence to stimulate pp60c-src activity and VEGF production is too. These data suggest that c-src may be an intermediary of both constitutive and inducible pathways for VEGF production in colon tumor cells.
Authors: Swadesh K Das; Sujit K Bhutia; Belal Azab; Timothy P Kegelman; Leyla Peachy; Prasanna K Santhekadur; Santanu Dasgupta; Rupesh Dash; Paul Dent; Steven Grant; Luni Emdad; Maurizio Pellecchia; Devanand Sarkar; Paul B Fisher Journal: Cancer Res Date: 2012-12-10 Impact factor: 12.701
Authors: Liz Y Han; Charles N Landen; Jose G Trevino; Jyotsnabaran Halder; Yvonne G Lin; Aparna A Kamat; Tae-Jin Kim; William M Merritt; Robert L Coleman; David M Gershenson; William C Shakespeare; Yihan Wang; Raji Sundaramoorth; Chester A Metcalf; David C Dalgarno; Tomi K Sawyer; Gary E Gallick; Anil K Sood Journal: Cancer Res Date: 2006-09-01 Impact factor: 12.701
Authors: Bing Xie; Jikui Shen; Aling Dong; Mara Swaim; Sean F Hackett; Lorenza Wyder; Susanne Worpenberg; Samuel Barbieri; Peter A Campochiaro Journal: FASEB J Date: 2008-04-01 Impact factor: 5.191
Authors: Lauren Averett Byers; Banibrata Sen; Babita Saigal; Lixia Diao; Jing Wang; Meera Nanjundan; Tina Cascone; Gordon B Mills; John V Heymach; Faye M Johnson Journal: Clin Cancer Res Date: 2009-10-27 Impact factor: 12.531
Authors: Eskil Eskilsson; Gro V Rosland; Krishna M Talasila; Stian Knappskog; Olivier Keunen; Andrea Sottoriva; Sarah Foerster; Gergely Solecki; Torfinn Taxt; Radovan Jirik; Sabrina Fritah; Patrick N Harter; Kristjan Välk; Jubayer Al Hossain; Justin V Joseph; Roza Jahedi; Halala S Saed; Sara G Piccirillo; Inma Spiteri; Lina Leiss; Philipp Euskirchen; Grazia Graziani; Thomas Daubon; Morten Lund-Johansen; Per Øyvind Enger; Frank Winkler; Christoph A Ritter; Simone P Niclou; Colin Watts; Rolf Bjerkvig; Hrvoje Miletic Journal: Neuro Oncol Date: 2016-06-10 Impact factor: 12.300