Effect Of SUMOylation Of DEC1 On Proliferation Of Breast Cancer MCF7 Cells

ObjectiveBreast cancer is the most common malignancy in women, and its incidence is increasing worldwide. Frequently occur at 40-60 years old women. The incidence of breast cancer in China has increased year by year, the trend was younger. Recent studies have found that breast cancer is a long-term development process of multi gene mutation, many cell factors are involved. With the increasing research on the pathogenesis, the roles of protein SUMOylation modification in the development process of breast cancer recives much attention.Dec1 is a basic helix loop helix(b HLH) structure transcription factor, participate in neural development, cartilage formation of immune response, and other important physiological processes, and is closely related to the occurrence and development of tumor. Previous study shows that DEC1 treads to over expression in colon, lung, kidney cancer and other tumor tissues, and through the regulation of TGF beta, P53 and other signaling pathways involves in tumor cell proliferation, invasion, migration, apoptosis of aging process. It suggests that DEC1 has a potential value to the research of the gene targeting therapy of tumor. In this study, we detected the expression of DEC1 in estrogen receptor positive(ER+) breast carcinoma tissue, and its relationship with clinicalpathological factors. Moreover, the effect of SUMOylation of DEC1 by cotransfection with DEC1 and SUMO1 plasmid on breast cancer MCF7 cells cycle and proliferation. Methods40 cases of estrogen receptor positive(ER+) primary breast cancer tissues were collected, the expression of DEC1 was measured by immunohistochemistry and the chi-square test was used in order estimate the relation between DEC1 and clinicopathological factors. MCF7 cells were transfected with different plasmids and divided into the following four experimental groups:(1) pc DNA3. 1 group,(2) SUMO1 group,(3) DEC1 group,(4) SUMO1+DEC1 group, and determined for expression of SUMOylation of DEC1 by Western blot. The effects of SUMOylation of DEC1 on cell cycle and proliferation of MCF7 cells were evaluated by Flow cytometry and CCK8 analysis respectively. ResultThe positive expression rates of DEC1 in the breast carcinoma with ER-positive were 27 recurrence or distant metastases, accounting for 67.5%, and negative patients, 13 people DEC1 protein expression and recurrence or distant transfer at 3, accounting for 23%. One way analysis showed that overexpression of DEC1 was significantly correlated with histological grading, TNM staging and lymph node status, but it was insignificantly correlated with age and HER2 protein expression. The results showed that DEC1 was successfully modified by SUMO1 in MCF7. The number of MCF7 cells in S and G2/M phases obviously increased while the percentage of cells in G1-phase decreased, and cell proliferation potential was significantly increased in the co-transfection group. ConclusionIn this study, in primary breast cancer with ER positive, the higher expression of DEC1, the poorer histological increase in the degree of DEC1, the expression level of DEC1 was related with the degree of malignant and invasion in breast cancer. The higher expression of DEC1, the more degree of malignant and invasive. It suggested us that DEC1 may act as a poor prognosis of primary breast cancer patients. Modification of SUMOylation of DEC1 significantly promoted MCF7 cell proliferation and division in vitro.