雌激素受体α36介导雌激素促进甲状腺乳头状癌细胞增殖的分子机制

Molecular mechanism of estrogen receptor alpha-36 in 17β-estradiol-promoted proliferation in human papillary thyroid carcinoma cells

目的研究雌激素受体α36(estrogen receptor alpha-36,ERα36)介导雌激素促进甲状腺乳头状癌(papillary thyroid carcinoma,PTC)细胞增殖的分子机制及相关信号通路。方法采用免疫组化(S-P)检测ERα36在34例人PTC组织标本及其21例配对癌旁组织标本中的表达;梯度浓度E2(0、10^(-7)、10^(-8)、10^(-9)mol/L)处理PTC细胞株K-1和BCPAP后,Western blot检测两种细胞株中ERα36的表达;10-8mol/L E2处理后,Western blot检测两种细胞株ERK1/2和AKT磷酸化水平的变化,以及ERα36-si RNA对其的抑制作用;梯度浓度的E2处理BCPAP细胞后,MTT法检测细胞增殖和ERα36-si RNA对增殖的抑制作用。结果在人PTC组织中ERα36的阳性表达率为82.4%,明显高于癌旁组织(P<0.05)。PTC细胞株K-1和BCPAP均表达ERα36;10-8mol/L E2处理细胞后,ERα36的表达增高,且呈时间依赖性。E2能促进BCPAP和K-1细胞ERK1/2和AKT蛋白磷酸化水平增高,且处理15 min时BCPAP细胞最明显,10 min时K-1细胞最明显,而ERα36-si RNA能抑制E2的诱导效果;E2促进BAPAP细胞增殖,ERα36-si RNA则抑制E2的诱导效果。结论 ERα36通过ERK/AKT途径介导雌激素促进PTC细胞增殖。

Objective To determine the effect of estrogen receptor-α36 （ERα36） on 17β-estradiol （E2）-promoted proliferation in papillary thyroid carcinoma （PTC） cells, and investigate the underlying mechanisms possibly involved. MethodsERα36 protein expression was analyzed in 34 PTC tissue samples and 21 matched paracancerous tissues by immunohistochemical assay （S-P）. Protein level of ERα36 in PTC cell lines BCPAP and K-1 in presence and absence of E2 （10-7, 10-8 and 10-9 mol/L） was detected by Western blotting. The levels of phosphorylated ERK1/2 and AKT were analyzed in the BCPAP and K-1 cells with 10-8 mol/L E2 treatment by Western blotting. The BCPAP and K-1 cells were assigned into control, E2, E2＋scrambled siRNA, and E2＋ERα36-siRNA groups. The effect of ERα36-siRNA on the expression of above proteins was tested by Western blotting. Proliferation of BCPAP cells after the treatment of gradient doses of E2 was measured by MTT assay, and the effect of ERα36-siRNA on the proliferation was also studied. ResultsThe positive rates of ERα36 were 82.4% in PTC tissues, which were significantly higher than those in adjacent normal tissues （P〈0.05）. Both BCPAP and K-1 cells expressed ERα36, and 10-8 mol/L E2 treatment enhanced the expression level in a time-dependent manner. E2 treatment also resulted in increases in the phosphorylation of ERK1/2 and AKT, and most significant increases were observed in 15 min after the treatment in the BCPAP cells and 10 min in the K-1 cells. However, ERα36-siRNA inhibited these above promotions. What’s more, E2 induced cell proliferation in the BCPAP cells, which was suppressed by ERα36-siRNA. ConclusionERα36 may medicate E2promoting proliferation of PTC cells through ERK/AKT pathway.