The effect of inhibition of Ca2+-independent phospholipase A2 on chemotherapeutic-induced death and phospholipid profiles in renal cells.
We demonstrate that cells derived from primary cultures of rabbit proximal tubules (RPTC), human embryonic kidney (HEK293) and human kidney carcinomas (Caki-1) express microsomal Ca(2+)-independent phospholipase A(2) (iPLA(2)gamma) and cytosolic Ca(2+)-independent phospholipase A(2) (iPLA(2)beta). Inhibition of iPLA(2) activity in these cells using the iPLA(2) inhibitor bromoenol lactone (BEL) (0-5.0microM) for 24h did not induce cell death as determined by annexin V and propidium iodide (PI) staining. However, BEL treatment prior to cisplatin (50muM) or vincristine (2microM) exposure reduced apoptosis 30-50% in all cells tested (RPTC, HEK293 and Caki-1 cells). To identify the phospholipids altered during cell death electrospray ionization-mass spectrometry and lipidomic analysis of HEK293 and Caki-1 cells was performed. Cisplatin treatment reduced 14:0-16:0 and 16:0-16:0 phosphatidylcholine (PtdCho) 50% and 35%, respectively, in both cell lines, 16:0-18:2 PtdCho in Caki-1 cells and increased 16:1-22:6 plasmenylcholine (PlsCho). BEL treatment prior to cisplatin exposure further decreased 14:0-16:0 PtdCho, 16:0-16:1 PlsCho and 16:0-18:1 PlsCho in HEK293 cells, and inhibited cisplatin-induced increases in 16:1-22:6 PlsCho in Caki-1 cells. Treatment of cells with BEL prior to cisplatin exposure also increased the levels of several arachidonic containing phospholipids including 16:0-20:4, 18:1-20:4, and 18:0-20:4 PtdCho, compared to cisplatin only treated cells. These data demonstrate that inhibition of iPLA(2) protects against chemotherapeutic-induced cell death in multiple human renal cell models, identifies specific phospholipids whose levels are altered during cell death, and demonstrates that alterations in these phospholipids correlate to the protection against cell death in the presence of iPLA(2) inhibitors.
Zhang
Ling
L
Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, USA.
Peterson
Brianna L
BL
Cummings
Brian S
BS
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology; D005260:Female; D054522:Group VI Phospholipases A2; D006801:Humans; D007668:Kidney / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010741:Phospholipases A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism*; D011817:Rabbits; D014750:Vincristine / Q000494:pharmacology
D000970:Antineoplastic Agents; D010743:Phospholipids; D014750:Vincristine; D010741:Phospholipases A; D054522:Group VI Phospholipases A2; C516475:PLA2G6 protein, human; D054467:Phospholipases A2; D002945:Cisplatin; D002118:Calcium