Qi C, Park J H, Gibbs T C, Shirley D W, Bradshaw C D, Ella K M, Meier K E
Department of Pharmacology, Medical University of South Carolina, Charleston 29425-2251, USA.
J Cell Physiol. 1998 Feb;174(2):261-72. doi: 10.1002/(SICI)1097-4652(199802)174:2<261::AID-JCP13>3.0.CO;2-F.
Phospholipase D (PLD) is activated in mammalian cells in response to a variety of growth factors and may play a role in cell proliferation. Lysophosphatidic acid (LPA) is a bioactive metabolite potentially generated as a result of PLD activation. Two human prostate cancer cell lines, PC-3 and LNCaP, express membrane PLD activity. The effects of LPA on PLD activity and proliferation were examined in PC-3 cells, which express hPLD1a/1b. Phorbol 12-myristate 13-acetate (PMA) induced a prolonged activation of PLD, as detected in both intact cells and membranes. LPA induced a transient activation of PLD that was maximal by 10 minutes. The EC50 for LPA-induced PLD activation was approximately 1 microM. Pertussis toxin did not inhibit activation of PLD by LPA or PMA. Ro-31-8220 and bisindolylmaleimide I, inhibitors of protein kinase C, blocked activation by PLD by both PMA and LPA. PMA-induced activation of PLD did not appear to require translocation of PLDs from cytosol to membrane. LPA stimulated proliferation of PC-3 cells with an EC50 of approximately 0.2 microM; this response was not inhibited by pertussis toxin. Perillyl alcohol, an anti-cancer drug, reversibly inhibited proliferation in response to either serum or LPA but did not inhibit activation of PLD by PMA or LPA. These data establish that LPA activates PLD and stimulates proliferation via Gi-independent pathways in a human prostate cancer cell line.
磷脂酶D（PLD）在哺乳动物细胞中因多种生长因子而被激活，可能在细胞增殖中发挥作用。溶血磷脂酸（LPA）是一种可能因PLD激活而产生的生物活性代谢产物。两种人前列腺癌细胞系PC-3和LNCaP表达膜PLD活性。在表达hPLD1a/1b的PC-3细胞中检测了LPA对PLD活性和增殖的影响。佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA）诱导PLD的长时间激活，在完整细胞和细胞膜中均能检测到。LPA诱导PLD的瞬时激活，在10分钟时达到最大值。LPA诱导PLD激活的EC50约为1微摩尔。百日咳毒素不抑制LPA或PMA对PLD的激活。蛋白激酶C抑制剂Ro-31-8220和双吲哚马来酰亚胺I阻断了PMA和LPA对PLD的激活。PMA诱导的PLD激活似乎不需要PLD从胞质溶胶转运到细胞膜。LPA以约0.2微摩尔的EC50刺激PC-3细胞增殖；该反应不受百日咳毒素抑制。抗癌药物紫苏醇可逆地抑制对血清或LPA的增殖反应，但不抑制PMA或LPA对PLD的激活。这些数据表明，在人前列腺癌细胞系中，LPA通过不依赖Gi的途径激活PLD并刺激增殖。
