Differential UVC radiation sensitivity in multidrug-resistant l1210 cells: Insights into p53 and Bcl-XL expression/function.

Multidrug-resistant (MDR) variants of L1210 cells, selected for resistance to vincristine (R) or doxorubicin (D), exhibit elevated ABCB1 (P-glycoprotein) expression but differ in UVC sensitivity. D cells resemble parental L1210 (S) cells, whereas R cells are significantly more UVC vulnerable. To investigate this, we analyzed the expression of genes involved in DNA damage response, Trp53 family members, cyclin-dependent kinase inhibitors (p15, p21), Bcl-2 family genes, and DNA repair genes in S, R, and D cells before and after UVC irradiation.