RESUMEN
Background and purpose:Micro-environmental hypoxia is a common phenomenon in most human solid tumors,and this investigation is done to observe the expression of HIF-1? and chemo-resistance-associated genes in human colon cancer cell line under hypoxic micro-environment in vitro,and study the influence of micro-environmental hypoxia on chemo-resistance and the possible mechanisms in human colon cancer.Methods:Human colon cancer cell line SW620 was cultured under hypoxia for 12,24,48 hr,with normoxia as control.Then the expression of HIF-1? and chemo-resistance-associated genes mdr1/P-Gp、LRP were investigated by RT-PCR and western-blot.Results:With prolongation of the hypoxic time,the mRNA expressions of HIF-1? and LRP remained at the same level,but the mRNA expressions of mdr1 showed a time-dependent increase(P