MicroRNA‑335 inhibits bladder cancer cell growth and migration by targeting mitogen‑activated protein kinase 1

N6-methyladenosine-modified CircPSMA7 enhances bladder cancer malignancy through the miR-128-3p/MAPK1 axis

Several studies have indicated that circular RNAs (circRNAs) play vital roles in the progression of various diseases, including bladder cancer (BCa). However, the underlying mechanisms by which circRNAs drive BCa malignancy remain unclear. In this study, we identified a novel circRNA, circPSMA7 (circbaseID:has_circ_0003456), showing increased expression in BCa cell lines and tissues, by integrating the reported information with circRNA-seq and qRT-PCR. We revealed that circPSMA7 is associated with a higher tumor grade and stage in BCa. M6A modification was identified in circPSMA7, and IGF2BP3 recognized this modification and stabilized circPSMA7, subsequently increasing the circPSMA7 expression. In vitro and in vivo experiments showed that circPSMA7 promoted BCa proliferation and metastasis by regulating the cell cycle and EMT processes. CircPSMA7 acted as a sponge for miR-128-3p, which showed antitumor effects in BCa cell lines, increasing the expression of MAPK1. The tumor proliferation and metastasis suppression induced by silencing circPSMA7 could be partly reversed by miR-128-3p inhibition. Thus, the METTL3/IGF2BP3/circPSMA7/miR-128-3p/MAPK1 axis plays a critical role in BCa progression. Furthermore, circPSMA7 may be a potential diagnostic biomarker and novel therapeutic target for patients with BCa.

In silico Identification of Hypoxic Signature followed by reverse transcription-quantitative PCR Validation in Cancer Cell Lines

Background

Hypoxic tumor microenvironment is one of the important impediments for conventional cancer therapy. This study aimed to computationally identify hypoxia-related messenger RNA (mRNA) signatures in nine hypoxic-conditioned cancer cell lines and investigate their role during hypoxia.

Methods

Nine RNA sequencing (RNA-Seq) expression data sets were retrieved from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified in each cancer cell line. Then 23 common DEGs were selected by comparing the gene lists across the nine cancer cell lines. Reverse transcription-quantitative PCR (qRT-PCR) was performed to validate the identified DEGs.

Results

By comparing the data sets, GAPDH, LRP1, ALDOA, EFEMP2, PLOD2, CA9, EGLN3, HK, PDK1, KDM3A, UBC, and P4HA1 were identified as hub genes. In addition, miR-335-5p, miR-122-5p, miR-6807-5p, miR-1915-3p, miR-6764-5p, miR-92-3p, miR-23b-3p, miR-615-3p, miR-124-3p, miR-484, and miR-455-3p were determined as common micro RNAs. Four DEGs were selected for mRNA expression validation in cancer cells under normoxic and hypoxic conditions with qRT-PCR. The results also showed that the expression levels determined by qRT-PCR were consistent with RNA-Seq data.

Conclusion

The identified protein-protein interaction network of common DEGs could serve as potential hypoxia biomarkers and might be helpful for improving therapeutic strategies.

Linc-ROR has a Potential ceRNA Activity for OCT4A by Sequestering miR-335-5p in the HEK293T Cell Line

Linc-ROR has a regulatory role in reprogramming, and the core stem cell transcription factors, OCT4, SOX2, and NANOG, regulate its expression. MicroRNAs (miRNAs) are also a critical constituent of pivotal posttranscriptional regulatory pathways. One of such interactions is a competing endogenous RNA interaction that connects small and long non-coding RNAs with coding transcripts. Here, we aimed to investigate the existence of such associations between OCT4A, Linc-ROR, hsa-miR-335-5p, and hsa-miR-544. Bioinformatic analysis was performed to evaluate the expression status of OCT4A, Linc-ROR, miR-335, and miR-544 throughout differentiation as well as in various differentiated cells. The complete lengths of OCT4A and Linc-ROR, and OCT4A 3'-UTR were cloned in the luciferase reporter vector, and the precursors of miR-335 and miR-544 were cloned in expression vectors. Following the overexpression of miR-335 and miR-544 in the 5637 cell line, the endogenous expression of OCT4A and Linc-ROR was evaluated. Afterward, the expression vectors of miRNAs and the reporter vectors of OCT4A/Linc-ROR were co-transfected in the HEK293T cell line. Via the Dual-Luciferase assay, the effect of the overexpression of miRNAs on their two possible targets (Linc-ROR and OCT4A) was investigated. The bioinformatic analysis demonstrated a relatively similar expression pattern for OCT4A and Linc-ROR, while miR-335 showed a different expression status. Both miR-335 and miR-544 inhibited the endogenous expression of OCT4A. The Dual-Luciferase assay likewise confirmed the inhibitory effect of miR-335 and miR-544 on OCT4A expression. In contrast, the miR-335 inhibitory effect was reversed in the presence of Linc-ROR, resulting in the upregulation of OCT4A. Such evidence suggests that Linc-ROR may compete with OCT4A to interact with miR-335.

MicroRNA-212 Targets Mitogen-Activated Protein Kinase 1 to Inhibit Proliferation and Invasion of Prostate Cancer Cells

Prostate cancer (PCa) is the second most commonly diagnosed malignancy and the fifth leading cause of cancer-related deaths in males worldwide. MicroRNAs (miRNAs) may serve as important regulators in PCa occurrence and development. Therefore, understanding the expression and functions of PCa-related miRNAs may be beneficial for the identification of novel therapeutic methods for patients with PCa. In this study, miRNA-212 (miR-212) was evidently downregulated in PCa tissues and several PCa cell lines. Functional assays showed that the resumption of miR-212 expression attenuated cell proliferation and invasion and increased the apoptosis of PCa. In addition, mitogen-activated protein kinase 1 (MAPK1), a well-known oncogene, was identified as a novel target of miR-212 in PCa, as confirmed by bioinformatics, luciferase reporter assay, qRT-PCR, and Western blot analysis. Furthermore, MAPK1 expression was upregulated in PCa tissues and inversely correlated with miR-212 expression. Rescue experiments also demonstrated that restored MAPK1 expression reversed the tumor-suppressing effects of miR-212 on PCa cell proliferation, invasion, and apoptosis. In conclusion, miR-212 may exert tumor-suppressing roles in PCa by regulating MAPK1 and could be a novel therapeutic target for treatment of patients with this malignancy.

Understanding the Role of Non-Coding RNAs in Bladder Cancer: From Dark Matter to Valuable Therapeutic Targets

The mortality and morbidity that characterize bladder cancer compel this malignancy into the category of hot topics in terms of biomolecular research. Therefore, a better knowledge of the specific molecular mechanisms that underlie the development and progression of bladder cancer is demanded. Tumor heterogeneity among patients with similar diagnosis, as well as intratumor heterogeneity, generates difficulties in terms of targeted therapy. Furthermore, late diagnosis represents an ongoing issue, significantly reducing the response to therapy and, inevitably, the overall survival. The role of non-coding RNAs in bladder cancer emerged in the last decade, revealing that microRNAs (miRNAs) may act as tumor suppressor genes, respectively oncogenes, but also as biomarkers for early diagnosis. Regarding other types of non-coding RNAs, especially long non-coding RNAs (lncRNAs) which are extensively reviewed in this article, their exact roles in tumorigenesis are—for the time being—not as evident as in the case of miRNAs, but, still, clearly suggested. Therefore, this review covers the non-coding RNA expression profile of bladder cancer patients and their validated target genes in bladder cancer cell lines, with repercussions on processes such as proliferation, invasiveness, apoptosis, cell cycle arrest, and other molecular pathways which are specific for the malignant transformation of cells.

Genome-wide profiling of micro-RNA expression in gefitinib-resistant human lung adenocarcinoma using microarray for the identification of miR-149-5p modulation

To understand the mechanism involved in gefitinib resistance, we established gefitinib-resistant human HCC827/GR-8-1 cell line from the parental HCC827 cell line. We compared the micro-RNA expression profiles of the HCC827 cells HCC827/GR-8-1 using Agilent micro-RNA microarrays. The micro-RNAs, such as the miR-149-5p, were up- or downregulated and associated with acquired gefitinib resistance. Quantitative real-time polymerase chain reaction was then performed to verify the expression patterns of different micro-RNAs. The result showed that miR-149-5p was upregulated in the HCC827/GR-8-1 cell line. To investigate the biological function of miR-149-5p in non-small cell lung cancer cells acquired gefitinib resistance, we examined cell proliferation using a cell counting kit-8 assay. Cell viability was evaluated after the miR-149-5p mimics, inhibitors, and negative control were separately transfected into the non-small cell lung cancer cells. The results showed that the non-small cell lung cancer cells transfected with miR-149-5p mimics exhibited reduced cell motility. The drug-sensitivity assay results revealed that the overexpression of miR-149-5p effectively evaluates the half maximal inhibitory concentration values of the cell in response to gefitinib, and the downregulation of miR-149-5p can attenuate the half maximal inhibitory concentration values of the cell lines in response to gefitinib. Furthermore, the levels of miR-149-5p in the HCC827 and HCC827/GR-8-1 cells were inversely correlated with caspase-3 expression. In conclusion, this study revealed that miR-149-5p is upregulated in the HCC827/GR-8-1 cells and involved in the acquired gefitinib resistance.