92P Tff1 Trefoil Protein Involves in Resistance to Doxorubicin-Induced Apoptosis in Breast Cancer Cell

Abstract

ABSTRACT TFF1 trefoil protein is a small secretory protein expressed in a various type of carcinomas including breast cancer. TFF1 gene contained estrogen responsive element and its expression could be regulated by estrogen. In addition, estrogen has been demonstrated its ability to promote resistance to doxorubicin in estrogen receptor positive MCF-7 breast cancer cell line. Moreover, it has been reported that TFF1 can protect conjunctival cells from UV-induced apoptosis. In this study, we demonstrated the role of TFF1 in estrogen-promoted resistance to doxorubicin-induced apoptosis using MCF-7 model. Permanent knockdown of TFF1 gene in MCF-7 cell had been generated and used to test the sensitivity to doxorubicin treatment compared to parental cell in the conditions present or absent of 17b-estradiol, a potent estrogenic agent. The apoptosis cells were measured by fluorescence staining and flow cytometry method. The results showed that among the stimulation of apoptosis by doxorubicin, 17b-estradiol could suppress this process in parental MCF-7 cell but not in TFF1 knockdown MCF-7 cell. Moreover, by trypan blue staining method, it has been shown that anti-TFF1 antibody could reverse the anti-apoptotic effect of estrogen in parental MCF-7 cell and recombinant TFF1 could recover TFF1 knockdown MCF-7 cell death induced by doxorubicin. However, this process could not be inhibited by fulvestrant, an estrogen antagonist. Apoptosis protein array experiment reflected the role of the anti-oxidative enzymes catalase and heme oxygenase 1 in estrogen and TFF1 modulated apoptosis. These phenomena determine the role of TFF1 in estrogen-promoted resistance to apoptosis induced by doxorubicin in MCF-7 breast cancer cell. TFF1 gene may be a target for enhancing of sensitivity to chemotherapy in breast cancer treatment. Disclosure All authors have declared no conflicts of interest.