MicroRNA-147 Induces a Mesenchymal-To-Epithelial Transition (MET) and Reverses EGFR Inhibitor Resistance

Abstract

BackgroundThe epithelial-mesenchymal transition (EMT) is a key developmental program that is often activated during cancer progression and may promote resistance to therapy. An analysis of patients (n = 71) profiled with both gene expression and a global microRNA assessment (∼415 miRs) identified miR-147 as highly anti-correlated with an EMT gene expression signature score and postulated to reverse EMT (MET).Methods and FindingsmiR-147 was transfected into colon cancer cells (HCT116, SW480) as well as lung cancer cells (A-549). The cells were assessed for morphological changes, and evaluated for effects on invasion, motility, and the expression of key EMT markers. Resistance to chemotherapy was evaluated by treating cells with gefitinib, an EGFR inhibitor. The downstream genes regulated by miR-147 were assayed using the Affymetrix GeneChip U133 Plus2.0 platform. miR-147 was identified to: 1. cause MET primarily by increasing the expression of CDH1 and decreasing that of ZEB1; 2. inhibit the invasion and motility of cells; 3. cause G1 arrest by up-regulating p27 and down-regulating cyclin D1. miR-147 also dramatically reversed the native drug resistance of the colon cancer cell line HCT116 to gefitinib. miR-147 significantly repressed Akt phosphorylation, and knockdown of Akt with siRNA induced MET. The morphologic effects of miR-147 on cells appear to be attenuated by TGF-B1, promoting a plastic and reversible transition between MET and EMT.ConclusionmiR-147 induced cancer cells to undergo MET and induced cell cycle arrest, suggesting a potential tumor suppressor role. miR-147 strikingly increased the sensitivity to EGFR inhibitor, gefitinib in cell with native resistance. We conclude that miR-147 might have therapeutic potential given its ability to inhibit proliferation, induce MET, as well as reverse drug sensitivity.

MicroRNA-147 suppresses proliferation, invasion and migration through the AKT/mTOR signaling pathway in breast cancer

“…Previous studies have reported that Akt may be a potential target of miR-147 (13,15). To investigate how miR-147 affects AKT, and the role of Akt in miR-147 induced cell proliferation, invasion and migration inhibition, western blotting was performed to assess the expression and phosphorylation of the Akt protein and the downstream key effectors in the Akt/mTOR pathway.…”

“…Other miRNAs including miR-144, miR-126, miR-199a-3p and miR-718, regulate the Akt/mTOR pathway in ovarian, oral, colorectal and human non-small-cell lung cancers and Kaposi's sarcoma (7)(8)(9)(10)(11). Few studies identified miRs regulating Akt/mTOR pathway in breast cancer (12)(13)(14)(15). MiR-122 was observed to inhibit the cell proliferation and tumorigenesis of breast cancer and to suppress the activation of the Akt/mTOR pathway by targeting IGF-1R, which is an upstream molecule of the Akt/mTOR pathway (12).…”

“…EGFR also serves a crucial role in the initiation of the Akt/mTOR pathway (14). Furthermore, MicroRNA-147 suppresses proliferation, invasion and migration through the AKT/mTOR signaling pathway in breast cancer miR-147 was found to repress cell invasion and proliferation, induce cell arrest at G1 in colon cancer (15). In addition, it has been shown that ectopic expression of miR-147 prevented Akt phosphorylation (15).…”

“…Furthermore, MicroRNA-147 suppresses proliferation, invasion and migration through the AKT/mTOR signaling pathway in breast cancer miR-147 was found to repress cell invasion and proliferation, induce cell arrest at G1 in colon cancer (15). In addition, it has been shown that ectopic expression of miR-147 prevented Akt phosphorylation (15). Although studies have identified miR-147 as a tumor suppressor (14,15), the effect and the corresponding mechanisms of miR-147 in breast cancer remains to be investigated.…”

“…In addition, it has been shown that ectopic expression of miR-147 prevented Akt phosphorylation (15). Although studies have identified miR-147 as a tumor suppressor (14,15), the effect and the corresponding mechanisms of miR-147 in breast cancer remains to be investigated. Here, the present study aimed to understand the effect of miR-147 on the biological behaviors of breast cancer cells, phosphorylation of Akt and the potential downstream pathways regulating these processes in breast cancer.…”