virology15tumorvir__培训课件.ppt

HCV core protein expression (+) and apoptosis genes Hep 191 cells engineered with core gene under induction control HepRXR cells w/o core KSHV and Kaposi’s sarcoma Virus expresses constitutive G protein coupled receptor Cells transfected with GPCR Blood vessels Human Umbilical Vein Endothelial cells (HUVECs) Grew transformed +/- GPCR 3T3 cells and collected medium. Added it to HUVECS and counted (3a) Concentration dependent (3b) Angiogenicity - microtubule formation HUVECs added on top of gel-like material and conditioned medium added (3c) Coculture expt - gel added on top of transfected cells and HUVECs added on top (3d) VEGF is a major angiogenic inducer Transfected cells w/ or w/o GPCR and measured VEGF in medium by ELISA (4a) Used antibody to VEGF to mitogenicity (4b) grey bar = anti-vegf; white bar = control ab Repear angiogencity expts (4c-d) Oncogenic Viruses “There is no single mechanism by which viruses cause tumors” Transformation and potential tumorigenesis Transformation - alteration in a cell’s properties that leads to immortalization and different growth patterns that result from alteration in cell cycle Loss of anchorage dependence Loss of contact inhibition (foci) Decreased requirements for growth factors Tumorigenesis (oncogenicity) - in vivo development of tumors Cell cycle M- mitosis G1 - cells grow S - DNA synthesis G2 - growth and preparation for mitosis G1/S decision point for going to dividing state Problem for DNA viruses that need S phase machinery Cell cycle control proteins Activation of cell cycle progression -cyclins, cyclin dependent protein kinases (Cdks), Cdk inhibitors Inhibitors of cell cycle progression - tumor suppressors Tumor suppressor Rb Rb binds to transcription factor E2F and prevents gene expression of proteins needed to go to S phase Tumor suppressor p53 P53 halts progression when DNA damaged to give cell time to repair or triggers apoptosis of damaged cell by activating Bcl-2 causing mitochondria to release cytochro