A Preliminary Study On The Correlation Between HSF1 Expression And Invasion And Metastasis In Triple Negative Breast Cancer And Its Regulatory Mechanism

ObjectiveBreast cancer is one of the most common malignant tumors endangering women’s health,and its mortality is on the rise in recent years.There are demographic differences in the incidence of breast cancer,which is higher in developing countries than in developed ones.Triple Negative Breast Cancer(TNBC)is a special type of breast cancer.Its estrogen receptor(ER),progesterone receptor(PR)and human epidermal growth factor receptor 2(HER2)are all negative.Compared with other subtypes of breast cancer,triple negative breast cancer has higher recurrence rate and shorter overall survival rate.Because of its high malignancy,easy recurrence,easy metastasis and lack of effective treatment methods,it has become a research hotspot to seek specific markers for triple negative breast cancer and provide new therapeutic targets for clinicopathological diagnosis and clinical treatment in recent years.Heat shock factor 1(HSF1)plays an important role in the normal development of the body.The abnormal expression of HSF1 is related to the occurrence and malignancy of malignant tumors.HSF1 can mediate the survival and metastasis of cancer cells,and is dysregulated in many cancers.HSF1 not only increases the expression of heat shock protein in tumors,but also plays a more direct and extensive role in the regulation of malignant behaviors of tumor cells,and plays an important role in the transformation,generation and progression of tumor cells.It is known that HSF1 and p-Akt are often co-activated in breast cancer cell lines.However,the expression of HSF1 in triple negative breast cancer and its mechanism of regulating invasion and metastasis are still unclear.Therefore,this study aims to explore the expression of HSF1 in triple negative breast cancer and its relationship with clinicopathological parameters;analyze the correlation between HSF1 and AKT pathway related proteins;and preliminarily study the molecular mechanism of how HSF1 regulates the invasion and metastasis of triple negative breast cancer.MethodsFrom January 2010 to December 2019,65 cases of wax specimens confirmed to be triple negative breast cancer after surgical resection were collected from the Department of Pathology,Affiliated Central Hospital of Shenyang Medical College as the experimental group,and 20 cases of wax specimens of non-triple negative breast cancer and 20 cases of benign breast hyperplasia were selected as the control group.Immunohistochemical methods were used to detect the expressions of HSF1 in triple negative breast cancer,non-triple negative breast cancer and benign breast hyperplasia.SPSS statistical software was used to analyze the relationship between HSF1 and important clinicopathological parameters related to the prognosis of triple negative breast cancer patients.In order to further study the mechanism of HSF1 regulating the invasion and metastasis of triple negative breast cancer,we used small interfering RNA(si RNA)to knockdown the expression level of HSF1 in triple negative breast cancer cell line(MDA-MB-231)and non-triple negative breast cancer cell line(MDA-MB-453),and then verified the knockdown effect of HSF1 by Western blot.Then,the metastatic ability of HSF1 knockdown triple negative breast cancer cell line(MDA-MB-231 si-HSF1)and negative control cell line(MDA-MB-231 si NC)and HSF1 knockdown non-triple negative breast cancer cell line(MDA-MB-453 si-HSF1)and negative control cell line(MDA-MB-453 si NC)was detected by scratch test,the invasion ability of triple negative breast cancer cell line(MDA-MB-231 si-HSF1),negative control cell line(MDA-MB-231 si NC),non-triple negative breast cancer cell line(MDA-MB-453 si-HSF1)and negative control cell line(MDA-MB-453 si NC)was detected by Transwell assay.Besides,Western blot assay was used to detect the influence of HSF1 knockdown on the expression level of related proteins.Then,immunohistochemistry was used to detect the expression of p-Akt and Slug in triple negative breast cancer,non triple negative breast cancer and benign breast hyperplasia.SPSS statistical software was used to analyze the relationship between p-Akt、Slug and important clinicopathological parameters related to the prognosis of triple negative breast cancer patients,as well as the correlation between HSF1 and p-Akt、Slug.Results1、The results of immunohistochemistry showed that HSF1 was highly expressed in triple negative breast cancer(72.31%),which was significantly higher than that in non-triple negative breast cancer and benign breast hyperplasia(20% and 5%).There was significant difference between the experimental group and the control group(P<0.01),and the positive expression of HSF1 was correlated with tumor diameter and lymph node metastasis(P<0.05),there was no correlation with age and histological grade.2、After the expression of HSF1 was down regulated by si RNA,scratch assay showed that compared with non-triple negative breast cancer cell lines,the metastatic ability of cells in triple negative breast cancer cell lines was decreased;Transwell assay showed that the invasion ability of triple negative breast cancer cells was lower than that of non-triple negative breast cancer cells;Western blot results showed that p-Akt/Akt was decreased in triple negative breast cancer cell lines compared with non-triple negative breast cancer cell lines,and the protein expression levels of Slug and N-cadherin were decreased.3、The results of immunohistochemistry showed that the positive expression rate of p-Akt in triple negative breast cancer was 46.15%,which was significantly higher than that in non-triple negative breast cancer and benign breast hyperplasia(10% and0%).The difference between the experimental group and the control group was statistically significant(P<0.01).The positive expression of p-Akt was correlated with age,lymph node metastasis and histological grade(P < 0.05),but not with tumor diameter and size.Slug was highly expressed in triple negative breast cancer(60%),which was significantly higher than that in non-triple negative breast cancer and benign breast hyperplasia(0% and 0%).The difference between the experimental group and the control group was statistically significant(P < 0.01).The positive expression of Slug was correlated with lymph node metastasis and histological grade(P<0.05),but not with age and tumor diameter.In triple negative breast cancer,HSF1 was positively correlated with p-Akt protein expression(r=0.435,P <0.001);HSF1 was positively correlated with Slug protein expression(r=0.547,P<0.001).Conclusions1、The positive expression of HSF1 and p-Akt,Slug in triple negative breast cancer were increased,which indicated that HSF1,p-Akt and Slug might be related to tumor growth,invasion and metastasis of triple negative breast cancer,and HSF1 might become a new target for the treatment of triple negative breast cancer.2、This study suggests that HSF1 can up-regulate the invasion and metastasis of triple negative breast cancer cell lines.HSF1 may up-regulate the malignant behavior of triple negative breast cancer cell lines through AKT,and affect the expression level of epithelial-mesenchymal transition related proteins.This study provides a strong research basis for further research in the future.