Eastham Linda L, Mills Caroline N, Niles Richard M
Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia 25755, USA.
Pharm Res. 2008 Jun;25(6):1327-33. doi: 10.1007/s11095-007-9524-9.
We examined the expression of PPARs and the effects of PPARalpha and PPARgamma agonists on growth of mouse and human melanocytes and melanoma cells.
PPARalpha,beta, and PPARgamma mRNA qualitative expression in melan-a mouse melanocytes, B16 mouse melanoma, human melanocytes, and A375 and SK-mel28 human melanoma cells was determined by RT-PCR, while quantitative PPARalpha mRNA levels were determined by QuantiGene assay. PPARalpha and PPARgamma protein was assessed by Western blotting. The effect of natural and synthetic PPAR ligands on cell growth was determined by either hemocytometer counting or crystal violet assay. PPAR transcriptional activity was determined by a PPRE-reporter gene assay, while knockdown of PPARalpha expression was achieved by transient transfection of siRNA.
Both mouse and human melanoma cells produced more PPARalpha and PPARgamma protein compared to melanocytes. PPARalpha mRNA levels were elevated in human melanoma cells, but not in mouse melanoma cells relative to melanocytes. Silencing of PPARalpha in human melanoma cells did not alter cell proliferation or morphology. PPARgamma-selective agonists inhibited the growth of both mouse and human melanoma cells, while PPARalpha-selective agonists had limited effects.
Increased expression of PPARalpha in melanoma relative to melanocytes may be a common occurrence, however its biologic significance remains to be determined. PPARgamma agonists may be useful for arresting the growth of some melanomas.
我们研究了过氧化物酶体增殖物激活受体（PPARs）的表达以及PPARα和PPARγ激动剂对小鼠和人类黑素细胞及黑色素瘤细胞生长的影响。
通过逆转录聚合酶链反应（RT-PCR）测定黑素-a小鼠黑素细胞、B16小鼠黑色素瘤、人类黑素细胞以及A375和SK-mel28人类黑色素瘤细胞中PPARα、β和PPARγ mRNA的定性表达，同时通过QuantiGene检测法定量测定PPARα mRNA水平。通过蛋白质免疫印迹法评估PPARα和PPARγ蛋白。通过血细胞计数器计数或结晶紫测定法确定天然和合成的PPAR配体对细胞生长的影响。通过PPRE报告基因测定法确定PPAR转录活性，同时通过小干扰RNA（siRNA）的瞬时转染实现PPARα表达的敲低。
与黑素细胞相比，小鼠和人类黑色素瘤细胞产生更多的PPARα和PPARγ蛋白。相对于黑素细胞，人类黑色素瘤细胞中PPARα mRNA水平升高，但小鼠黑色素瘤细胞中未升高。在人类黑色素瘤细胞中沉默PPARα不会改变细胞增殖或形态。PPARγ选择性激动剂抑制小鼠和人类黑色素瘤细胞的生长，而PPARα选择性激动剂的作用有限。
相对于黑素细胞，黑色素瘤中PPARα表达增加可能是常见现象，但其生物学意义仍有待确定。PPARγ激动剂可能有助于阻止某些黑色素瘤的生长。
