Targeting specificity protein 1 with miR-128-3p overcomes TGF-β1 mediated epithelial-mesenchymal transition in breast cancer: An in vitro study

Circulating microRNA Biomarker for Detecting Breast Cancer in High-Risk Benign Breast Tumors

High-risk benign breast tumors are known to develop breast cancer at high rates. However, it is still controversial whether they should be removed during diagnosis or followed up until cancer development becomes evident. Therefore, this study sought to identify circulating microRNAs (miRNAs) that could serve as detection markers of cancers arising from high-risk benign tumors. Small RNA-seq was performed using plasma samples collected from patients with early-stage breast cancer (CA) and high-risk (HB), moderate-risk (MB), and no-risk (Be) benign breast tumors. Proteomic profiling of CA and HB plasma was performed to investigate the underlying functions of the identified miRNAs. Our findings revealed that four miRNAs, hsa-mir-128-3p, hsa-mir-421, hsa-mir-130b-5p, and hsa-mir-28-5p, were differentially expressed in CA vs. HB and had diagnostic power to discriminate CA from HB with AUC scores greater than 0.7. Enriched pathways based on the target genes of these miRNAs indicated their association with IGF-1. Furthermore, the Ingenuity Pathway Analysis performed on the proteomic data revealed that the IGF-1 signaling pathway was significantly enriched in CA vs. HB. In conclusion, these findings suggest that these miRNAs could potentially serve as biomarkers for detecting early-stage breast cancer from high-risk benign tumors by monitoring IGF signaling-induced malignant transformation.

Empagliflozin mediated miR-128-3p upregulation promotes differentiation of hypoxic cancer stem-like cells in breast cancer

AIMS

The hsa-miR-128-3p expression is downregulated in advanced breast cancer patients. Empagliflozin (EMPA) is an anti-diabetic drug with anticancer potential. The present study investigated the effect of EMPA on cancer cell differentiation by acting as a miR-128-3p mimicking drug in breast cancer.

MAIN METHODS

Our results first demonstrate SP1 and PKM2 as the downstream effectors of hsa-miR-128-3p. Further, transfection with siPKM2, miR-128-3p mimics, and inhibitors was performed to assess their involvement in cancer stemness using flow cytometry. Further, EMPA as miR-128-3p mimicking drug was screened and explored on cancer cell differentiation. Then, we treated the 4T1-Red-FLuc allograft breast tumor with EMPA to assess its inhibitory potential toward tumor growth using IVIS® Spectrum. Immunohistochemistry was performed to evaluate cancer cell differentiation and cell proliferation.

KEY FINDINGS

We found that hsa-miR-128-3p is the upstream regulator of SP1 and PKM2 in hypoxic breast cancer cells. Overexpression of miR-128-3p with mimics downregulate SP1 and PKM2, whereas miR-128-3p inhibitor shows an opposite effect. The enhanced expression of miR-128-3p and PKM2 knockdown diminishes hypoxia-induced CD44 expression and enhance CD44⁺/CD24⁺ differentiated cells. We also identified EMPA as the miR-128-3p mimicking drug that can enhance the differentiated cell population. Further, EMPA suppressed in vivo tumor growth, lung metastasis, tumor bioluminescence, and cell proliferation. Therefore, EMPA abrogates breast cancer stemness by inactivating SP1 and PKM2 via enhanced miR-128-3p expression.

SIGNIFICANCE

EMPA could be a promising drug in combination with other chemotherapeutic drugs in advanced breast cancer.