MicroRNAs (miRNAs) are small non-coding RNA molecules of 21-24 nt that regulate the expression of other genes by transcriptional inhibition or translational repression. Multiple lines of evidence suggest that miRNAs play important roles in tumor development and progression. We identified 24 miRNAs markedly and aberrantly expressed in human cervical cancer. The most significantly deregulated was miR-143 as determined by miRNA microarray analysis. miR-143 was introduced into HeLa cells and it was found that the overexpression of miR-143 significantly inhibited HeLa cell proliferation and promoted apoptosis; anti-miR-143 rescued the effects. HeLa cells transfected with pre-miR-143, pre‑anti-miR-143 or control miRNA precursor were injected subcutaneously into the flanks of female athymic nude mice, and the overexpression of miR-143 suppressed the formation of tumors. Compared with normal cervical tissues, the levels of Bcl-2 were increased in miR-143-downregulated tissues. Sustained overexpression of miR-143 in HeLa cells resulted in suppression of Bcl-2 expression, and knockdown of miR-143 by anti-miR-143 increased Bcl-2 expression. In addition, overexpression of Bcl-2 partially reversed the inhibition of proliferation and promotion of apoptosis in the HeLa cells caused by miR-143. Furthermore, miR-143 suppressed the activity of a luciferase reporter carrying the 3'-UTR of Bcl-2, which was abolished by mutation of the predicted miR-143-binding site, indicating that Bcl-2 is a miR-143 target gene. Our study revealed a molecular link between miR-143 and Bcl‑2. Direct involvement in the regulation of Bcl-2 may be one of the mechanisms through which miR-143 may play a role in the pathogenesis of cervical cancer.

Idiopathic pulmonary fibrosis (IPF) is characterized by lung remodeling arising from epithelial injury, aberrant fibroblast growth, and excessive deposition of extracellular matrix. Repeated epithelial injury elicits abnormal wound repair and lung remodeling, often associated with alveolar collapse and edema, leading to focal hypoxia. Here, we demonstrate that hypoxia is a physiological insult that contributes to pulmonary fibrosis (PF) and define its molecular roles in profibrotic activation of lung epithelial cells. Hypoxia increased transcription of profibrotic genes and altered the proteomic signatures of lung epithelial cells. Network analysis of the hypoxic epithelial proteome revealed a crosstalk between transforming growth factor-β1 and FAK1 (focal adhesion kinase-1) signaling, which regulated transcription of galectin-1, a profibrotic molecule. Galectin-1 physically interacted with and activated FAK1 in lung epithelial cells. We developed a novel model of exacerbated PF wherein hypoxia, as a secondary insult, caused PF in mice injured with subclinical levels of bleomycin. Hypoxia elevated expression of phosphorylated FAK1, galectin-1, and α-smooth muscle actin and reduced caspase-3 activation, suggesting aberrant injury repair. Galectin-1 inhibition caused apoptosis in the lung parenchyma and reduced FAK1 activation, preventing the development of hypoxia-induced PF. Galectin-1 inhibition also attenuated fibrosis-associated lung function decline. Further, galectin-1 transcript levels were increased in the lungs of IPF patients. In summary, we have identified a profibrotic role of galectin-1 in hypoxia signaling driving PF.

AHNAK, also known as desmoyokin, is a giant protein with the molecular size of approximately 700 kDa and exerts diverse functions in different types of cancer. In the present study, we demonstrated that AHNAK mRNA levels were down-regulated in 7 out of 8 human breast cancer cell lines, especially in triple - negative breast cancer (TNBC) cell lines. Moreover, in patients with TNBC, the expression of AHNAK gene was inversely correlated with the tumor status (P = 0.015), lymph node status (P < 0.001), lymph node (LN) infiltration (P < 0.001) and TNM stage (P < 0.001). Moreover, down-regulated AHNAK expression was considered an independent prognostic factor associated with the poor survival of patients with TNBC. Overexpression of AHNAK in two TNBC cell lines, MDA-MB-231 and BT549, suppressed the in vitro TNBC cell proliferation and colony formation, and inhibited the in vivo TNBC xenograft growth and lung metastasis. The tumor suppressing effect of AHNAK in TNBC was associated with the AKT/MAPK signaling pathway and Wnt/β-catenin pathway. Consistent results were observed when AHNAK was knockdown in BT20 and MDA-MB-435 cells. Taken together, our results suggest that AHNAK acts as a tumor suppressor that negatively regulates TNBC cell proliferation, TNBC xenograft growth and metastasis via different signaling pathways.

The purpose of this study was to elucidate the regulation of programmed death ligand 1 (PDL1), lactate dehydrogenase A (LDHA) and miR-34a in triple negative breast cancer (TNBC) and to explore the function and mechanism of PDL1 and LDHA as competitive endogenous RNAs (ceRNAs) in TNBC via regulation of miR-34a. Western blotting, quantitative RT-PCR (qRT-PCR) and immunohistochemistry (IHC) assays were conducted to explore the expression of PDL1, LDHA and miR-34a in TNBC and correlations between them. MTS cell viability, Transwell migration, glucose consumption and lactate production assays and flow cytometry were performed and mouse xenograft models were constructed to explore the functions and regulation of the PDL1 3’UTR and LDHA 3’UTR and miR-34a in TNBC. We found that PDL1 and LDHA were synchronously upregulated in TNBC cell lines and tissues. Co-expression of PDL1 and LDHA was correlated with poor outcome in TNBC. Both PDL1 and LDHA are targets of miR-34a, and the 3’UTRs of PDL1 and LDHA both have binding sites for miR-34a. The functions of PDL1 and LDHA were inhibited by miR-34a. In addition, PDL1 and LDHA acted as ceRNAs to promote the expression and function of each other through regulation of miR-34a in TNBC. This study provides a new theoretical basis for a novel TNBC therapeutic strategy. Simultaneously targeting PDL1 and LDHA, which would combine immunotherapy and metabolically targeted treatments, might shed some light on the treatment of breast cancer, especially TNBC.

PTEN phosphorylation at its C-terminal (C-tail) serine/threonine cluster negatively regulates its tumor suppressor function. However, the consequence of such inhibition and its downstream effects in driving lung cancer remain unexplored. Herein, we ascertain the molecular mechanisms by which phosphorylation compromises PTEN function, contributing to lung cancer. Replacement of the serine/threonine residues with alanine generated PTEN-4A, a phosphorylation-deficient PTEN mutant, which suppressed lung cancer cell proliferation and migration. PTEN-4A preferentially localized to the nucleus where it suppressed E2F1-mediated transcription of cell cycle genes. PTEN-4A physically interacted with the transcription factor E2F1 and associated with chromatin at gene promoters with E2F1 DNA-binding sites, a likely mechanism for its transcriptional suppression function. Deletion analysis revealed that the C2 domain of PTEN was indispensable for suppression of E2F1-mediated transcription. Further, we uncovered cancer-associated C2 domain mutant proteins that had lost their ability to suppress E2F1-mediated transcription, supporting the concept that these mutations are oncogenic in patients. Consistent with these findings, we observed increased PTEN phosphorylation and reduced nuclear PTEN levels in lung cancer patient samples establishing phosphorylation as a bona fide inactivation mechanism for PTEN in lung cancer. Thus, use of small molecule inhibitors that hinder PTEN phosphorylation is a plausible approach to activate PTEN function in the treatment of lung cancer.

MiR-200c is a cMyc-activated miRNA that promotes nasopharyngeal carcinoma by downregulating PTEN