ER-α36对乳腺癌细胞Herceptin敏感性的影响

Estrogen receptor α36 affects sensitivity of breast cancer cells to Herceptin

目的探讨乳腺癌细胞中雌激素受体α36(estrogen receptorα36,ER-α36)对人表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)人源化单克隆抗体赫赛汀(Herceptin)治疗敏感性的影响。方法 Western blot对G418筛选的BT474/ER-α36细胞和对照细胞BT474/V进行表型鉴定;细胞增殖分析观察常规培养条件下和雌二醇(E2)存在与否的条件下配对细胞对Herceptin敏感性的差异;Western blot检测Herceptin处理前后配对细胞中E2诱导的Akt及MAPK磷酸化差异。结果筛选并鉴定了ER-α36过表达的BT474/ER-α36细胞及对照细胞BT474/V;常规培养下,Herceptin对BT474/ER-α36和BT474/V细胞的增殖抑制率分别为(22.00±0.06)%和(42.00±0.06)%,与对照细胞比较,BT474/ER-α36细胞对Herceptin的敏感性明显减弱(P<0.01);细胞经去类固醇处理后,在E2存在的情况下,Herceptin对BT474/ER-α36和BT474/V细胞的增殖抑制率分别为(34.00±0.06)%和(53.00±0.06)%,E2显著降低了BT474/ER-α36对Herceptin的敏感性(P<0.01);BT474/ER-α36细胞E2诱导的HER2下游信号分子Akt和MAPK磷酸化水平分别上调了3.08倍和2.63倍,而BT474/V细胞E2诱导的Akt和MAPK磷酸化水平仅分别上调了2.37倍和1.72倍,与对照细胞比较,BT474/ER-α36细胞具有更强的E2非基因组活性,并且该细胞中Herceptin抑制Akt及MAPK磷酸化的效应明显减弱(P<0.01)。结论 ER-α36可通过非基因组活性影响乳腺癌细胞Herceptin的敏感性。

Objective To determine the effect of estrogen receptor α36 （ER-α36） on the sensitivity to Hereeptin, a humanized monoelonal antibody directed against human epidermal growth factor receptor 2 （HER2）, in breast cancer cell lines. Methods G418 was used for the screening for ER-α36 over-expressing breast cancer cell line BT474/ER-α36 and control cell line BT474/V, and then the phenotype of the paired cells was identified by Western blotting. The sensitivity of the paired cells to Hereeptin was observed in normal culture condition and in the presence or absence of estrogen （E2） by cell proliferation assay. Western blotting was used to detect the different phosphorylation levels of E2-induced Akt and MAPK in the paired cells before and after Heceptin treatment. Results ER-α36 over-expressing breast cancer cell line BT474/ER-α36 and control cell line BT474/V had been screened successfully. In normal culture condition, the inhibitory ratio of Herceptin on the proliferation of BT474/ER-α36 and BT474/V cells was （22.00 ± 0.06） % and （42.00 ±0. 06）%, respectively, indicating that the sensitivity of BT474/ER-α36 cells to Herceptin was obviously attenuated, compared with control cells （P 〈 0.01 ）. In the presence of E2, the inhibitory ratio of Herceptin on the proliferation of BT474/ER-α36 and BT474/V cells deprived of steroid hormones was （ 34.00 ± 0.06 ） % and （53.00 ±0.06）%, respectively, indicating that E2 significantly decreases the sensitivity of BT474/ER- α36 cells to Herceptin. E2-induced phosphorylation of Akt or MAPK, a downstream molecule of HER2 pathway, was up-regulated over 3.08 fold or 2.63 fold, in BT474/ER-ot36 cells, but only was up-regulated over 2.37 fold or 1.72 fold, in BT474/V cells. Compared with BT474/V control cells, the higher E2-induced ERα-36 non genomic activities and the weaker inhibition of phosphorylation of Akt and MAPK caused by Herceptin were found in BT474/ER-α36 cells （P 〈 0.01 ）. Conclusion ER-α36 can affect the sensitivity of breast cancer cells to Herceptin through non-genomic activity.