Overexpressing KRAS by another KRAS overexpression vector (G12V) in KRAS wild-type CRC cells leads to oxaliplatin sensitivity and ERCC1 downregulation.

(A) KRASG12V-DDK-myc-COLO320DM cells were more sensitive to oxaliplatin, but have the same sensitivity to irinotecan, 5FU, and doxorubicin than parental COLO320DM cells, as demonstrated by MTT assay. (B) The protein level of ERCC1, but not those of TOPO1 or TS, was downregulated after COLO320DM cells were transfected by the KRASG12V mutant vector. (C) The mRNA level of ERCC1, but not those of TOPO1 or TS, was downregulated after COLO320DM cells were transfected by the KRASG12V mutant vector. **: p<0.01. (D) Increased percentage of apoptosis, from 22.5%±0.2% to 39.1%±0.2% of apoptosis (P<0.001), has been demonstrated when KRASwt-DDK-myc-COLO320DM cells, were compared to KRASG12V-DDK-myc-COLO320DM cells, in which, both were treated by the same concentration of oxaliplatin in 5 µM. *: p<0.001.