| Breast cancer is one of the most common malignant tumors in women. Whetherin developed or developing countries, the incidence and mortality rates of breastcancer are relatively high. The causes of breast cancer are quite complex, in additionto genetic factors, high-fat diet, obesity, hormones, immune, and variousenvironmental factors (physical and chemical, biological factors and lifestyle, etc.)may lead to the occurrence of breast cancer. Estrogen is inextricably linked with theincidence of breast cancer. With the development of theory and technology in cellbiology and molecular biology, breast cancer has been recognized as a diseasecaused by multi-gene mutation. Improvement in the understanding of relevantgenetic abnormality in the development of breast cancer is the key to the preventionand treatment of breast cancer.DHRS7is the seventh member of the SDR family, locates on chromosome14q23.1, and encods a protein which contains339amino acids and has a molecularweight of38kDa and expresses in the cytoplasm. DHRS7is a kind ofdehydrogenation oxidoreductase dependent on NADP+or NAD+, mainly involved inthe metabolism of steroid and retinol. Studies have reported that the function ofDHRS7is similar with that of11β-hydroxysteroid steroid reductase1(11β-HSD1) inSDR family.11β-HSD1can regulate the metabolism of glucocorticoids which couldpromote the resolve of fat and increase the concentrations of fatty acids, Theinhibitory effects of glucocorticoids on breast cancer cells have been reported.Epidemiological studies in breast cancer have shown that the contents and kinds offatty acids in the diet are related with the occurrence and development of breastcancer. Reports showed that fatty acids can inhibit the proliferation of breastcancer,which depends on the concentration. Dimberg et al. found that retinoic acid could inhibit the proliferation of cells in breast cancer cells. Significant inhibition ofall-trans retinoic acid on the proliferation of breast cancer cells has been found.DHR-S7is involved in the regulation of the process of all trans retinoic acids generatedfrom retinol and is a rate-limiting enzyme.The low expression of DHRS7is relatedwith the metatasis of prostate cancer. In summary, it has been inferred that there is acertain relationship between the DHRS7and breast cancer and relevant researcheshave not been reported.In this study, effects of DHRS7on the cell cycle of human breast cancer cellline MCF-7and its relationship with the infiltration of breast cancer were determinedto open up a new way to explore the complex etiology and seek treatment targets ofbreast cancer.Methods:1.Construction of pcDNA3.1-DHRS7recombinant eukaryotic expressionplasmid: DHRS7gene was obtained by reverse transcriptase-PCR, then constructthe recombinant eukaryotic expression plasmid pcDNA3.1-DHRS7.The plasmidpcDNA3.1-DHRS7was identified through PCR and digestion by enzyme.2.Group of the experiment: blank control group、negative control group ofpcDNA3.1、the overexpression of group of pcDNA3.1-DHRS7and interferencegroup of pGenesil-shRNA-DHRS7.3.Analysis of the changes of cell cycle by flow cytometry: All plsamids weretransfected into MCF-7cells using Fugene HD transfection agent, and theexpressions of DHRS7were determined by RT-PCR and Western blot. The cellcycles were analyzed by flow cytometry.4.The expressions of DHRS7protien in mammary gland carcinoma in situ andinfiltrating carcinoma were detected by immunohistochemical staining, then theresults were analyzed.Results：1.The recombinant plasmid pcDNA3.1-DHRS7was constructed correctly.2.mRNA analysis and Western blot showed that expression of DHRS7protien in overexpression plasmid group was higher than that in control group（P<0.05）andthat expression of DHRS7protien in interference group was lower than that incontrol group（P<0.05）. Flow cytometry showed the up-regulated expression ofDHRS7caused the increase of MCF-7cells in S phase （P<0.05） and thedown-regulated expression of DHRS7caused the increase of cells in G2period（P<0.05）.3.Immunohistochemical staining: The expression level of DHRS7protein ishigher in the mammary gland carcinoma than that in the mammary gland infiltratingcarcinoma (P<0.01).Conclusion：1.DHRS7gene may be involved in the regulation of cell cycles in MCF-7cells,the high expression of DHRS7can inhibit cell proliferation.2.The expression inhibition of DHRS7may promote infiltration of the breastcancer. |
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