| Research BackgroundIn the world,breast cancer is the most common malignancy among women,and the number of cases has steadily increased over the past few decades.Breast cancer is the fifth most common cause of cancer death and the second most common cause of cancer death among women.The most effective treatment of breast cancer is surgical resection.Recently,more attention has also been paid to whether surgery can reduce the risk of cancer recurrence and metastasis.Sevoflurane is one of the most commonly used anesthetic drugs during perioperative period.Many of anesthetists and patients of all ages prefer Sevoflurane to others on account of its unique advantages.Sevoflurane is non-irritating,the concentration used routinely in clinical practice is non-combustible and non-explosive,the blood gas distribution coefficient is low,the solubility in blood is small,the gas concentration in the alveoli increases rapidly,the anesthesia induction process is rapid,and it is widely used for the induction and maintenance in general anesthesia.Sevoflurane can also inhibit inflammation,induce apoptosis,and inhibit the development of tumors.MicroRNA(mi RNA)is a small non-coding RNA thatregulates gene expression by binding to the 3' end of messenger RNA(m RNA).More and more studies have also shown that miRNAs can affect the proliferation,metastasis and invasion of tumor cells.The specific role of miRNA in different disease settings remains largely unknown.MiR-203 has also been reported as a potential marker for early detection of cervical cancer lymph node metastasis.However,whether or how sevoflurane regulates the development and signaling of breast cancer cells is still unclear now.This study may reveal the regulatory effect of sevoflurane on breast cancer,suggesting that miRNA may be a potential target for breast cancer prevention and treatment.ObjectiveThis study aims to investigate whether sevoflurane can inhibit breast cancer cell proliferation through inhibiting microRNA-203 level.Materials and methodsBreast cancer cells were purchased from the Cell Bank Type Culture Collection of Chinese Academy of Sciences,grown in RPMI-1640 medium.The experiment was conducted through three parts.In the first part,to discuss the effect of Sevoflurane on breast cancer cell proliferation,cells were randomly divided into control group and Sevoflurane group.In the second part,cells were randomly divided into miR-203 control group,miR-203 group,miR-203 inhibitor control group,miR-203 inhibitor group to investigate the influence of miR-203 on breast cancer proliferation.Finally,we carried out rescue experiment that cells were randomly divided into control group,Sevoflurane group and Sevoflurane+ miR-203 inhibitor group.Cells requiring sevoflurane treatment were exposed to 2% sevoflurane for 6 hours.MTS method was used to detect cell proliferation,using bromine deoxyuridine(Brd U)mixed with experimental analysis counting Brd U number of positive cells,using real-time fluorescent quantitative PCR technique to detect the expression of cell cycle related genes---cyclin D cyclin E and inhibit cell cycle genes---Rb1,P21 and P27.Western Blot technical analyed the relative expression of cell cycle related genes---cyclin D cyclin E and inhibit cell cycle genes---Rb1,P21 and P27.Flow cytometry was used to detect the proportion of cells in every cell cycle in breast cancer cells.Results(1)Sevoflurane inhibits the proliferation of breast cancer cellsCompared with the control group,the proliferation of breast cancer cells in the Sevoflurane group was inhibited,the expression levels of cyclin D and cyclin E which are the cyclin-related genes were decreased,and the expression levels of Rb1,P21 and P27,the cell cycle inhibitory genes were increased,and the difference was statistically significant(P<0.05),indicating that Sevoflurane could inhibit the proliferation of breast cancer cells.(2)The level of miR-203 treated with sevoflurane in breast cancer cells was up-regulated and inhibited the proliferation of breast cancer cellsCompared with control group,miR-203 expression was up-regulated in breast cancer cells of Sevoflurane group,and the difference was statistically significant(P<0.05).Breast cancer cells that were transfected with pre-miR-203 found that miR-203 significantly inhibited cell proliferation.On the contrary,cancer cells transfected with miR-203 inhibitor could promote cell proliferation,and the difference was statistically significant(P<0.05).The expression of cyclin D and cyclin E levels were significantly decreased in miR-203 group,but cell cycle control genes Rb1,P21 and P27 expressed increasing,miR-203 inhibitor group of cyclin D cell and cyclin E levels raised obviously,but cell cycle control genes Rb1,P21 and P27 expression levels dropped,the differences were statistically significant(P < 0.05),confirmed that the miR-203 levels in cancer cells was up-regulated after sevoflurane treatment.In a word,miR-203 could inhibit the proliferation of breast cancer cells.(3)MiR-203 inhibitor can save the effect of sevoflurane on breast cancer cellsWhen the cancer cells transfected with miR-203 inhibitor were treated with sevoflurane,the ability of inhibiting the proliferation of cancer cells was similar to that of the control group,and the difference was not statistically significant(P>0.05).Compared with the Sevoflurane group,the effect of Sevoflurane+miR-203 inhibitor group on inhibiting the proliferation of cancer cells was not significant,and the difference was statistically significant(P<0.05).Compared with control group,there was no difference in the expression levels of cyclin D,cyclin E and cyclin Rb1,P21 and P27 in the Sevoflurane+miR-203 inhibitor group(P>0.05).Compared with control group,the expression levels of cyclin D and cyclin E of cell cycle relatede Resultsgenes in the Sevoflurane+miR-203 inhibitor group were up-regulated,and the expression levels of cyclin Rb1,P21 and P27 of cell cycle inhibitory genes were down-regulated.The differences were statistically significant(P<0.05),which fully demonstrated that miR-203 inhibitor could save the effect of sevoflurane on breast cancer cells.ConclusionSevoflurane can inhibit the proliferation of breast cancer cells by regulating the level of microRNA-203. |
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