4-PIPERIDINOPIPERIDINE-RESISTANT LYMPHOMA-CELLS WERE RESISTANT TO DEXAMETHASONE-INDUCED AND A23187-INDUCED APOPTOSIS

4-Piperidinopiperidine is a side residue of CPT-11, a derivative of ca mptothecin. We have previously established a 4-piperidinopiperidine-re sistant lymphoma cell line, 4-pp-R, which was co-resistant to CPT-11. We report here that this cell line is cross-resistant to dexamethasone and A23187 which induce apoptosis in parent RVC cells. Examination of apoptosis related gene expression by RT-PCR showed that bcl-2 express ion was greater in 4-pp-R than in RVC. p53, bar and bcl-x(L) were expr essed at the same level in 4-pp-R and RVC cells. These results suggest that upregulation of bcl-2 in 4-pp-R cells is related to the resistan ce to CPT-11 as well as to A23187 or dexamethasone. (C) 1998 Elsevier Science Ireland Ltd.