The effect of Shugan-Yishen formula on HER2-ERK/MAPK-ERα Pathway of TAM-resistant breast cancer cell lines

Abstract

Objective To investigate the effect of Shugan-Yishen formula on Tamoxifen-resistant MCF-7 cell line（LCC9） through HER2-ERK/MAPK-ERα pathway. Methods Four serums were prepared with the method of serum pharmacology：the serum of Shugan-Yishen formula, Shugan-Yishen formula plus Tamoxifen（TAM）, blank and TAM alone. After LCC-9 cells were affected in the above-mentioed serums in vitro, the inhibition rate and the level of mRNA as well as the protein expression of HER2, ERα, ERK/MAPK, p-ERK/MAPK were detected. Results MTT showed that TAM alone group、Shugan-Yishen formula group and the Shugan-Yishen formula plus TAM group had higher inhibition rates at 48th hour, the inhibition rates was（6.61±0.129）%, （47.43±2.24）%, （54.19±3.364）%, compared to the blank group, Shugan-Yishen formula group and the Shugan-Yishen formula plus TAM group had a stronger inhibition on LCC9 at 48th hour （P〈0.05）, and the combination group was better than Shugan-Yishen formula alone（P〈0.05）, there was no difference between TAM group compared to the blank group（P〉0.05）. RT-PCR result showed that compared to the blank group, the expression levels of ESR1 mRNA of group of Shugan Yishen formula plus TAM＆amp;nbsp;werehigher by and large at 48th hour （P〈0.05）, the expression of ESR1 mRNA was（2.282±0.185）;and the levels of ERBB2, MAPK3 mRNAwere lower（P〈0.05）, which levels were（0.71±0.095）, （0.336±0.058）. Western blotting result showed that Shugan-Yishen Formula plus TAM group could markedly decrease the expression of HER2, p-ERK/MAPK of LCC9 at 48th hour （P〈0.05）, which the expressions were（0.708± 0.072）, （0.228±0.034）, and the expression of ER-αelevated（P〈0.05）. There was no significant difference on ERK/MAPK（P〉0.05）. Conclusions ①The combination of Shugan-Yishen formula with tamoxifen can inhibit the LCC9 cells. The inhibition effect reaches the peak at 48th hour. ②The mechanism of Shugan-Yishen formula plus TAM combination effects on human breast cancer TAM-resistant cell line LCC9 may improve the sensitivity of ERαby inhibiting the expression of HER2, ERK/MAPK. Key words: Shugan-Yishen Formula; Breast cancer; HER2-ERK/MAPK-ERαpathway