Roles of miR-497 and its potential signaling pathway in diseases and with vascular endothelial growth factor

Extracellular vesicles released by hypoxia-induced tumor-associated fibroblasts impart chemoresistance to breast cancer cells via long noncoding RNA H19 delivery

Recently, extracellular vesicles (EVs) have been emphasized in regulating the hypoxic tumor microenvironment of breast cancer (BC), where tumor-associated fibroblasts (TAFs) play a significant role. In this study, we describe possible molecular mechanisms behind the pro-tumoral effects of EVs, secreted by hypoxia (HP)-induced TAFs, on BC cell growth, metastasis, and chemoresistance. These mechanisms are based on long noncoding RNA H19 (H19) identified by microarray analysis. We employed an in silico approach to identify differentially expressed lncRNAs that were associated with BC. Subsequently, we explored possible downstream regulatory mechanisms. We isolated EVs from TAFs that were exposed to HP, and these EVs were denoted as HP-TAF-EVs henceforth. MTT, transwell, flow cytometry, and TUNEL assays were performed to assess the malignant phenotypes of BC cells. A paclitaxel (TAX)-resistant BC cell line was constructed, and xenograft tumor and lung metastasis models were established in nude mice for in vivo verification. Our observation revealed that lncRNA H19 was significantly overexpressed, whereas miR-497 was notably downregulated in BC. HP induced activation of TAFs and stimulated the secretion of EVs. Coculture of HP-TAF-EVs and BC cells led to an increase in TAX resistance of the latter. HP-TAF-EVs upregulated methylation of miR-497 by delivering lncRNA H19, which recruited DNMT1, thus lowering the expression of miR-497. In addition, lncRNA H19-containing HP-TAF-EVs hindered miR-497 expression, enhancing tumorigenesis and TAX resistance of BC cells in vivo. Our study presents evidence for the contribution of lncRNA H19-containing HP-TAF-EVs in the reduction of miR-497 expression through the recruitment of DNMT1, which in turn promotes the growth, metastasis, and chemoresistance of BC cells.

Non-coding RNAs in lung cancer: emerging regulators of angiogenesis

Lung cancer is the second cancer and the leading cause of tumor-related mortality worldwide. Angiogenesis is a crucial hallmark of cancer development and a promising target in lung cancer. However, the anti-angiogenic drugs currently used in the clinic do not achieve long-term efficacy and are accompanied by severe adverse reactions. Therefore, the development of novel anti-angiogenic therapeutic approaches for lung cancer is urgently needed. Non-coding RNAs (ncRNAs) participate in multiple biological processes in cancers, including tumor angiogenesis. Many studies have demonstrated that ncRNAs play crucial roles in tumor angiogenesis. This review discusses the regulatory functions of different ncRNAs in lung cancer angiogenesis, focusing on the downstream targets and signaling pathways regulated by these ncRNAs. Additionally, given the recent trend towards utilizing ncRNAs as cancer therapeutics, we also discuss the tremendous potential applications of ncRNAs as biomarkers or novel anti-angiogenic tools in lung cancer.

Targeting c-Jun in A549 Cancer Cells Exhibits Antiangiogenic Activity In Vitro and In Vivo Through Exosome/miRNA-494-3p/PTEN Signal Pathway

The oncogene c-Jun is activated by Jun N-terminal kinase (JNK). Exosomes are nanometer-sized membrane vesicles released from a variety of cell types, and are essential for cell-to-cell communication. By using specific JNK inhibitor SP600125 or CRISPR/Cas9 to delete c-Jun, we found that exosomes from SP600125-treated A549 cancer cells (Exo-SP) or from c-Jun-KO-A549 cells (Exo-c-Jun-KO) dramatically inhibited tube formation of HUVECs. And the miR-494 levels in SP600125 treated or c-Jun-KO A549 cells, Exo-SP or Exo-c-Jun-KO, and HUVECs treated with Exo-SP or Exo-c-Jun-KO were significantly decreased. Meanwhile, Exo-SP and Exo-c-Jun-KO enhanced expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Addition of miR-494 agomir in Exo-c-Jun-KO treated HUVECs inhibited PTEN expression and promoted tube formation, suggesting the target of miR-494 might be PTEN in HUVECs. Moreover, A549 tumor xenograft model and Matrigel plug assay demonstrated that Exo-c-Jun-KO attenuated tumor growth and angiogenesis through reducing miR-494. Taken together, inhibition of c-Jun in A549 cancer cells exhibited antiangiogenic activity in vitro and in vivo through exosome/miRNA-494-3p/PTEN signal pathway.

MicroRNA-497 suppresses osteosarcoma tumor growth in vitro and in vivo

It has been demonstrated that microRNA-497 (miR-497) acts as a tumor suppressor and is involved in tumor progression, development and metastasis in several types of cancer. However, little is known about the exact role of miR-497 in osteosarcoma (OS). The aim of the current study was to investigate the potential role of miR-497 in human OS. The role of miR-497 in the growth and survival of OS cells was determined using several in vitro approaches and a nude mouse model. The results demonstrated that exogenous expression of miR-497 in human OS MG63 cells suppressed cell proliferation, colony formation, migration and invasion, and induced cell apoptosis and cell arrest at the G0/G1 phase of the cell cycle. In addition, the results of the in vivo study indicated that restoration of miR-497 inhibited OS tumor growth in a nude mouse model. Overall, the results of the present study identified a crucial tumor suppressive role of miR-497 in the progression of OS, and suggested that miR-497 may be a potential therapeutic agent for the treatment of OS.

Associations among four polymorphisms (BsmI, FokI, TaqI and ApaI) of vitamin D receptor gene and end-stage renal disease: a meta-analysis

BACKGROUND AND AIMS

To evaluate the association between vitamin D receptor (VDR) BsmI, FokI, TaqI and ApaI gene polymorphisms and the risk of end-stage renal disease (ESRD).

METHODS

All eligible studies were included in our meta-analysis of a search of the PubMed, Cochrane and China National Knowledge Infrastructure (CNKI) databases according to predefined criteria. The fixed-effects or random-effects models were used to calculate the pooled odds ratio (OR) and corresponding 95% confidence interval (CI).

RESULTS

Thirteen studies including 1510 patients and 1812 controls were recruited for the analysis of the association between the VDR BsmI, FokI, TaqI and ApaI gene polymorphisms and the risk of ESRD.VDR BsmI B allele, BB genotype and bb genotype, FokI F allele, FF genotype and ff genotype, TaqI T allele, TT genotype and tt genotype, ApaI A allele, AA genotype and aa genotype were not associated with ESRD susceptibility for overall populations, Asians and Caucasians.

CONCLUSIONS

Results from the current study suggest that VDR BsmI, FokI, TaqI and ApaI gene polymorphisms are not associated with the risk of ESRD in the overall populations, Asians and Caucasians. However, more studies should be performed in the future.