Patel Manish I, Singh Jaskirat, Niknami Marzieh, Kurek Caroline, Yao Mu, Lu Sasa, Maclean Fiona, King Nicholas J C, Gelb Michael H, Scott Kieran F, Russell Pamela J, Boulas John, Dong Qihan
Department of Surgery, The University of Sydney, Sydney, Australia.
Clin Cancer Res. 2008 Dec 15;14(24):8070-9. doi: 10.1158/1078-0432.CCR-08-0566.
Cytosolic phospholipase A2-alpha (cPLA2-alpha) provides intracellular arachidonic acid to supply both cyclooxygenase and lipoxygenase pathways. We aim to determine the expression and activation of cPLA2-alpha in prostate cancer cell lines and tissue and the effect of targeting cPLA2-alpha in vitro and in vivo.
The expression of cPLA2-alpha was determined in prostate cancer cells by reverse transcription-PCR, Western blot, and immunocytochemistry. Growth inhibition, apoptosis, and cPLA2-alpha activity were determined after inhibition with cPLA2-alpha small interfering RNA or inhibitor (Wyeth-1). Cytosolic PLA2-alpha inhibitor or vehicle was also administered to prostate cancer xenograft mouse models. Finally, the expression of phosphorylated cPLA2-alpha was determined by immunohistochemistry in human normal, androgen-sensitive and androgen-insensitive prostate cancer specimens.
cPLA2-alpha is present in all prostate cancer cells lines, but increased in androgen-insensitive cells. Inhibition with small interfering RNA or Wyeth-1 results in significant reductions in prostate cancer cell numbers, as a result of reduced proliferation as well as increased apoptosis, and this was also associated with a reduction in cPLA2-alpha activity. Expression of cyclin D1 and phosphorylation of Akt were also observed to decrease. Wyeth-1 inhibited PC3 xenograft growth by approximately 33% and again, also reduced cyclin D1. Immunohistochemistry of human prostate tissue revealed that phosphorylated cPLA2-alpha is increased when hormone refractory is reached.
Expression and activation of cPLA2-alpha are increased in the androgen-insensitive cancer cell line and tissue. Inhibition of cPLA2-alpha results in cells and xenograft tumor growth inhibition and serves as a potentially effective therapy for hormone refractory prostate cancer.
胞质型磷脂酶A2-α（cPLA2-α）为环氧化酶和脂氧合酶途径提供细胞内花生四烯酸。我们旨在确定cPLA2-α在前列腺癌细胞系和组织中的表达及激活情况，以及在体外和体内靶向cPLA2-α的效果。
通过逆转录聚合酶链反应、蛋白质印迹法和免疫细胞化学法测定前列腺癌细胞中cPLA2-α的表达。在用cPLA2-α小干扰RNA或抑制剂（惠氏-1）抑制后，测定细胞生长抑制、凋亡及cPLA2-α活性。还将胞质型磷脂酶A2-α抑制剂或赋形剂施用于前列腺癌异种移植小鼠模型。最后，通过免疫组织化学法测定人正常、雄激素敏感和雄激素不敏感前列腺癌标本中磷酸化cPLA2-α的表达。
cPLA2-α存在于所有前列腺癌细胞系中，但在雄激素不敏感细胞中表达增加。用小干扰RNA或惠氏-1抑制可导致前列腺癌细胞数量显著减少，这是由于增殖减少以及凋亡增加所致，同时这也与cPLA2-α活性降低有关。还观察到细胞周期蛋白D1的表达及Akt的磷酸化减少。惠氏-1抑制PC3异种移植瘤生长约33%，同样也降低了细胞周期蛋白D1。人前列腺组织的免疫组织化学显示，当达到激素抵抗时，磷酸化cPLA2-α增加。
cPLA2-α的表达及激活在雄激素不敏感癌细胞系和组织中增加。抑制cPLA2-α可导致细胞和异种移植瘤生长受抑制，有望成为激素抵抗性前列腺癌的有效治疗方法。
