Mechanism Of Suppression On Proliferation Of Human Colon Carcinoma Cell Line SW480 By The Combination Of TPL And OXA

Partâ… Mechanism of suppression on proliferation of human colon carcinoma cell line SW480 by oxaliplatinTo observe the effects of oxaliplatin on proliferation in human colon carcinoma cell lines SW480 in vitro and investigate the mechanism.Methods: The inhibition of proliferation in SW480 cell wasestimated by MTT assay . Morphologic changes were observed by AO/EB fluorescent staining.Distribution of cell cycle and apoptosis was analyzed by using flow cytometry.The expression of cell cycle protein and apoptosis-associated gene protein was detected with Western-blot technique.Results: Oxaliplatin could inhibit the proliferation of SW480 cells and the inhibition depended on the exposure dose and time。When treated with oxaliplatin for 48h,apoptotic cells could be found under the fluorescence microscope.The analysis of cell cycle indicated that oxaliplatin blocked cells at S phases and cells of G₂ / M phase reduced . The expression of Bax was up-regulated ; Bcl-2 down-regulated.Partâ…¡Establishment and biological characteristics of human colon carcinoma multidrug·resistant cell line SW480/L-OHPTo establish a drug-resistant human colon cancer cell line to oxaliplatin(L-OHP) based on cell line SW480.Methods A resistant cell line-SW480/L-OHP was established by gradually increasing the dose of L-OHP and intermittent administration.The growth curves, muhidrug resistance and resistance index of SW480/L-OHP cell line to anticancer agents were detected by MTT assay.The changes of its biological characteristics were determ ined by light microscopy,electron microscopy,and flow cytometry.Results SW480/L-OHP cell line was established after 6 months,which had stable resistance to L-OHP and a resistance index of 6.23.SW480/L-OHP cells exhibited cross resistance to many other chemotherapeutic agents.As compared with parental cells,the morphological of SW480/L-OHP was changed;its doubling time was prolonged;and the number of cells in S phase decreased while in G₀/G₁ and G₂/M phase increased.Partâ…¢Study on reversing multi-drug resistance by TPL in SW480/L-OHPTo evaluate the reversal effect of TPL in Oxaliplatin drug-resistant cell lines SW480/L-OHP,and explore the mechanisms of activities of TPL.Methods The reversal efficacy of TPL was measured by MTT.The effect of TPL on Rh123 uptake and efflux were analyzed by flow cytometer. The expression of HSP70 was detected with Western-blot technique.Results Inhibitory rates of 4ng/ml and 8ng/ml TPL for SW480/L-OHP cells were under 10% ,so this concentration was as innocuous dosage of TPL. At this dosage,reversal fold of TPL on SW480/L-OHP cells was respectively 2.30 and 3.91 .TPL could increase the toxicity of L-OHP in SW480/L-OHP greatly.The efficacy was dose-dependent TPL could decrease cellular Rh123 efflux and increase its accumulation. When the SW480/L-OHP cells was treated with TPL for 48h,the expression of HSP70 was down-regulated.