ABSTRACT
Effective therapeutic targets for triple-negative breast cancer (TNBC), a special type of breast cancer (BC) with rapid metastasis and poor prognosis, are lacking, especially for patients with chemotherapy resistance. Decitabine (DCA) is a Food and Drug Administration-approved DNA methyltransferase inhibitor that has been proven effective for the treatment of tumors. However, its antitumor effect in cancer cells is limited by multidrug resistance. Cancer stem cells (CSCs), which are thought to act as seeds during tumor formation, regulate tumorigenesis, metastasis, and drug resistance through complex signaling. Our previous study found that miR-155 is upregulated in BC, but whether and how miR-155 regulates DCA resistance is unclear. In this study, we demonstrated that miR-155 was upregulated in CD24- CD44+ BC stem cells (BCSCs). In addition, the overexpression of miR-155 increased the number of CD24- CD44+ CSCs, DCA resistance and tumor clone formation in MDA-231 and BT-549 BC cells, and knockdown of miR-155 inhibited DCA resistance and stemness in BCSCs in vitro. Moreover, miR-155 induced stemness and DCA resistance by inhibiting the direct target gene tetraspanin-5 (TSPAN5). We further confirmed that overexpression of TSPAN5 abrogated the effect of miR-155 in promoting stemness and DCA resistance in BC cells. Our data show that miR-155 increases stemness and DCA resistance in BC cells by targeting TSPAN5. These data provide a therapeutic strategy and mechanistic basis for future possible clinical applications targeting the miR-155/TSPAN5 signaling axis in the treatment of TNBC.
Subject(s)
Decitabine/pharmacology , Drug Resistance, Neoplasm/genetics , Gene Expression Regulation, Neoplastic , MicroRNAs/genetics , Neoplastic Stem Cells/metabolism , Tetraspanins/genetics , Triple Negative Breast Neoplasms/genetics , Antimetabolites, Antineoplastic/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Proliferation/genetics , Female , Gene Knockdown Techniques , Humans , Signal Transduction/drug effects , Signal Transduction/genetics , Tetraspanins/metabolism , Triple Negative Breast Neoplasms/metabolism , Triple Negative Breast Neoplasms/pathologyABSTRACT
OBJECTIVE: To investigate the levels of blood pressure and serum lipids, and examine the relationship between hypertension and hyperlipidemia in Hei Yi Zhuang Chinese living in Guangxi. METHODS: A total of 1056 people of Hei Yi Zhuang ethnicity were studied. Blood pressure, body height, body weight, and serum levels of lipids and apolipoprotein were measured. The data were compared with those in 925 people of Han ethnicity, who live in the same region. RESULTS: Systolic blood pressure and pulse pressure were significantly higher in Hei Yi Zhuang than Han Chinese (P < 0.001). The prevalence of isolated systolic hypertension and hypertension was also significantly higher in Hei Yi Zhuang than Han Chinese (P < 0.001). Serum concentrations of total cholesterol, triglycerides, low-density lipoprotein cholesterol, and apolipoprotein (Apo) B, and the prevalence of hypercholesterolemia and hyperlipidemia were significantly lower in Hei Yi Zhuang than Han Chinese (P < 0.05). Serum concentrations of high-density lipoprotein cholesterol and the Apo A1 to Apo B ratio were significantly higher in Hei Yi Zhuang than Han Chinese (P < 0.001). The prevalence of hypertension in Hei Yi Zhuang Chinese was positively associated with triglycerides (r = 0.425, P < 0.05), whereas the prevalence of hypertension in Han Chinese was positively correlated with total cholesterol (r = 0.623, P < 0.001). CONCLUSION: The present study revealed a significant difference in blood pressure and serum lipids between Hei Yi Zhuang and Han ethnic groups, and an association between hypertension and hyperlipidemia.
