Modulation of in vitro chemosensitivity by extracellular Ca++ in adriamycin sensitive and resistant P388 leukemic cells.
P388 mouse lymphocytic leukemia cells sensitive (P388/S) and resistant to adriamycin (P388/Adr), respectively, were exposed in vitro to 3 dose concentrations of adriamycin, mitoxantrone, vincristine and cisplatin in the presence and absence of extracellular Ca++ at 37 degrees C for 1 h. The absence of extracellular Ca++ enhanced the cytotoxicity of all the four drugs by 25 to 30% in P388/S cells. P388/Adr cells retained their resistance to adriamycin irrespective of the presence or absence of Ca++, however, vincristine and cisplatin to which P388/Adr cells, in normal course, show cross-resistance, exhibited a 30-40% enhancement of cytotoxicity in the absence of extracellular Ca++. Cross-resistance of P388/Adr to mitoxantrone was totally circumvented in the absence of extracellular Ca++.
Adwankar
M K
MK
Cellular Chemotherapy Unit, Tata Memorial Centre, Parel, Bombay, India.
Chitnis
M P
MP
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004273:DNA, Neoplasm / Q000096:biosynthesis; D004317:Doxorubicin / Q000494:pharmacology*; D004351:Drug Resistance; D007941:Leukemia P388 / Q000473:pathology*; D007942:Leukemia, Experimental / Q000473:pathology*; D051379:Mice; D008811:Mice, Inbred DBA; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
D004273:DNA, Neoplasm; D004317:Doxorubicin; D014700:Verapamil; D002118:Calcium