miR-663 sustains NSCLC by inhibiting mitochondrial outer membrane permeabilization (MOMP) through PUMA/BBC3 and BTG2

A detailed review on the role of miRNAs in mitochondrial-nuclear cross talk during cancer progression

MicroRNAs (miRNAs) are a class of small non-coding RNAs that are associated with biochemical pathways through the post-transcriptional regulation of gene expression in different cell types. Based on their expression pattern and function, miRNAs can have oncogenic and tumor suppressor activities in different cancer cells. Altered mitochondrial function and bioenergetics are known hallmarks of cancer cells. Mitochondria play a central role in metabolic reprogramming during cancer progression. Cancer cells exploit mitochondrial function for cell proliferation, invasion, migration and metastasis. Genetic and epigenetic changes in nuclear genome contribute to altered mitochondrial function and metabolic reprogramming in cancer cells. Recent studies have identified the role of miRNAs as major facilitators of anterograde and retrograde signaling between the nucleus and mitochondria in cancer cells. Detailed analysis of the miRNA-mediated regulation of mitochondrial function in cancer cells may provide new avenues for the diagnosis, prognosis, and therapeutic management of the disease. Our review aims to discuss the role of miRNAs in nuclear-mitochondrial crosstalk regulating mitochondrial functions in different cancer types. We further discussed the potential application of mitochondrial miRNAs (mitomiRs) targeting mitochondrial biogenesis and metabolism in developing novel cancer therapy.

The therapeutic potential of RNA m(6)A in lung cancer

Lung cancer (LC) is a highly malignant and metastatic form of cancer. The global incidence of and mortality from LC is steadily increasing; the mean 5-year overall survival (OS) rate for LC is less than 20%. This frustrating situation may be attributed to the fact that the pathogenesis of LC remains poorly understood and there is still no cure for mid to advanced LC. Methylation at the N6-position of adenosine (N6mA) of RNA (m(6)A) is widely present in human tissues and organs, and has been found to be necessary for cell development and maintenance of homeostasis. However, numerous basic and clinical studies have demonstrated that RNA m(6)A is deregulated in many human malignancies including LC. This can drive LC malignant characteristics such as proliferation, stemness, invasion, epithelial-mesenchymal transition (EMT), metastasis, and therapeutic resistance. Intriguingly, an increasing number of studies have also shown that eliminating RNA m(6)A dysfunction can exert significant anti-cancer effects on LC such as suppression of cell proliferation and viability, induction of cell death, and reversal of treatment insensitivity. The current review comprehensively discusses the therapeutic potential of RNA m(6)A and its underlying molecular mechanisms in LC, providing useful information for the development of novel LC treatment strategies.

microRNAs, oxidative stress, and genotoxicity as the main inducers in the pathobiology of cancer development

Cancer is one of the most serious leading causes of death in the world. Many eclectic factors are involved in cancer progression including genetic and epigenetic alongside environmental ones. In this account, the performance and fluctuations of microRNAs are significant in cancer diagnosis and treatment, particularly as diagnostic biomarkers in oncology. So, microRNAs manage and control the gene expression after transcription by mRNA degradation, or also they can inhibit their translation. Conspicuously, these molecular structures take part in controlling the cellular, physiological and pathological functions, which many of them can accomplish as tumor inhibitors or oncogenes. Relatively, Oxidative stress is defined as the inequality between the creation of reactive oxygen species (ROS) and the body's ability to detoxify the reactive mediators or repair the resulting injury. ROS and microRNAs have been recognized as main cancer promoters and possible treatment targets. Importantly, genotoxicity has been established as the primary reason for many diseases as well as several malignancies. The procedures have no obvious link with mutagenicity and influence the organization, accuracy of the information, or fragmentation of DNA. Conclusively, mutations in these patterns can lead to carcinogenesis. In this review article, we report the impressive and practical roles of microRNAs, oxidative stress, and genotoxicity in the pathobiology of cancer development in conjunction with their importance as reliable cancer biomarkers and their association with circulating miRNA, exosomes and exosomal miRNAs, RNA remodeling, DNA methylation, and other molecular elements in oncology.

Novel DNA methylation-based epigenetic signatures in colorectal cancer from peripheral blood leukocytes

Colorectal cancer (CRC) is a multifactorial disease characterized by accumulation of multiple genetic and epigenetic alterations, transforming colonic epithelial cells into adenocarcinomas. Alteration of DNA methylation (DNAm) is a promising biomarker for predicting cancer risk and prognosis, but its role in CRC tumorigenesis is inconclusive. Notably, few DNAm studies have used pre-diagnostic peripheral blood (PB) DNA, causing difficulty in postulating the underlying biologic mechanism of CRC initiation. We conducted epigenome-wide association (EWA) scans in postmenopausal women from Women's Health Initiative (WHI) with their pre-diagnostic DNAm in PB leukocytes (PBLs) to prospectively evaluate CRC development. Our site-specific DNAm analyses across the genome adjusted for DNAm-age, leukocyte heterogeneities, as well as body mass index, diabetes, and insulin resistance. We validated 20 top EWA-CpGs in 2 independent CRC tissue datasets. Also, we detected differentially methylated regions (DMRs) associated with CRC, further mapped to transcriptomic profile, and finally conducted a Gene Set Enrichment Analysis. We detected multiple novel CpGs validated across WHI and tissue datasets. In particular, 2 CpGs (B4GALNT4cg10321339, SV2Bcg18144285) had the strongest effect on CRC risk. Results from our DMR scans contained MIR663cg06007966, which was also validated in EWA analyses. Also, we detected 1 methylome region in PEG10 of Chr7 shared across datasets. Our findings reflect both novel and well-established epigenomic and transcriptomic sites in CRC, warranting further functional validations. Our study contributes to better understanding of the complex interrelated mechanisms on the methylome underlying CRC tumorigenesis and suggests novel preventive DNAm-targets in PBLs for detecting at-risk individuals for CRC development.

Deregulation of the miR-19b/PPP2R5E Signaling Axis Shows High Functional Impact in Colorectal Cancer Cells

MicroRNA (miR)-19b is deregulated in colorectal cancer (CRC) and locally advanced rectal cancer (LARC), predicting worse outcome and disease progression in CRC patients, and acting as a promising prognostic marker of patient recurrence and pathological response to 5-fluorouracil (5-FU)-based neoadjuvant chemoradiotherapy in LARC. Moreover, there is a strong inverse correlation between miR-19b and PPP2R5E in LARC, and both predict the response to neoadjuvant therapy in LARC patients. However, the functional role of the miR-19b/PPP2R5E axis in CRC cells remains to be experimentally evaluated. Here, we confirm with luciferase assays that miR-19b is a direct negative regulator of PPP2R5E in CRC, which is concordant with the observed decreased PP2A activity levels after miR-19b overexpression. Furthermore, PPP2R5E downregulation plays a key role mediating miR-19b-induced oncogenic effects, increasing cell viability, colonosphere formation ability, and the migration of CRC cells. Lastly, we also confirm the role of miR-19b mediating 5-FU sensitivity of CRC cells through negative PPP2R5E regulation. Altogether, our findings demonstrate the functional relevance of the miR-19b/PPP2R5E signaling pathway in disease progression, and its potential therapeutic value determining the 5-FU response of CRC cells.

MicroRNA panels as diagnostic biomarkers for colorectal cancer: A systematic review and meta-analysis

Background

Circulating microRNAs (miRNA) have emerged as promising diagnostic biomarkers for several diseases, including cancer. However, the diagnostic accuracy of miRNA panels in colorectal cancer (CRC) remains inconsistent and there is still lack of meta-analyses to determine whether miRNA panels can serve as robust biomarkers for CRC diagnosis.

Methods

This study performed a systematic review and meta-analysis to evaluate the clinical utility of miRNA panels as potential biomarkers for the diagnosis of CRC. The investigation systematically searched PubMed, Medline, Web of Science, Cochrane Library, and Google Scholar (21-year span, between 2000 and 2021) to retrieve articles reporting the diagnostic role of miRNA panels in detecting CRC. Diagnostic meta-analysis of miRNA panels used diverse evaluation indicators, including sensitivity, specificity, Positive Likelihood Ratio (PLR), Negative Likelihood Ratio (NLR), Diagnostic Odds Ratio (DOR), and the area under the curve (AUC) values.

Results

Among the 313 articles identified, 20 studies met the inclusion criteria. The pooled estimates of miRNA panels for the diagnosis of CRC were 0.85 (95% CI: 0.84-0.86), 0.79 (95% CI: 0.78-0.80), 4.06 (95% CI: 3.89-4.23), 0.20 (95% CI: 0.19-0.20), 22.50 (95% CI: 20.81-24.32) for sensitivity, specificity, PLR, NLR, and DOR, respectively. Moreover, the summary receiver operating characteristics (SROC) curve revealed an AUC value of 0.915 (95% CI: 0.914-0.916), suggesting an outstanding diagnostic accuracy for overall miRNA panels. Subgroup and meta-regression analyses demonstrated that miRNA panels have the highest diagnostic accuracy within serum samples, rather than in other sample-types - with a sensitivity, specificity, PLR, NLR, DOR, and AUC of 0.87, 0.86, 7.33, 0.13, 55.29, and 0.943, respectively. Sensitivity analysis revealed that DOR values did not differ markedly, which indicates that the meta-analysis had strong reliability. Furthermore, this study demonstrated no proof of publication bias for DOR values analyzed using Egger's regression test (P > 0.05) and funnel plot. Interestingly, miR-15b, miR-21 and miR-31 presented the best diagnostic accuracy values for CRC with sensitivity, specificity, PLR, NLR, DOR, and AUC values of 0.95, 0.94, 17.19, 0.05, 324.81, and 0.948, respectively.

Conclusion

This study's findings indicated that miRNA panels, particularly serum-derived miRNA panels, can serve as powerful and promising biomarkers for early CRC screening.

Systematic review registration

[www.crd.york.ac.uk/prospero], identifier [CRD42021268172].

Lower expression of KAI1 as a biomarker of poor survival prognosis of melanoma combined with colorectal cancer metastasis

Objective

This study aimed to investigate the correlation between KAI1 (CD82) and miR-633 expression and prognosis and survival time of patients with melanoma combined with colorectal cancer (CRC).

Methods

Clinical and follow-up data of melanoma and CRC patients were recorded, and the expression levels of KAI1 and miR-633 were detected. Pearson chi-square tests and Spearman correlation coefficient were used to analyze the relationship between prognosis and related parameters in these patients. Cox proportional risk regression and receiver operating characteristic curve analyses were used.

Results

Overall, 195 patients were included. KAI1 and miR-633 expression levels were significantly correlated with the prognosis of patients with melanoma combined with CRC. Spearman correlation analysis showed that the expression levels of KAI1 and miR-633 were significantly correlated with the prognosis of patients. Multivariate Cox regression analysis suggested that low expression levels of KAI1 and high expression levels of miR-633 indicated shorter survival time for patients.

Conclusions

KAI1 expression was significantly correlated with melanoma and CRC patient prognosis. When KAI1 expression levels were low, the patient survival time was poor.

MiR-183-5p-PNPT1 Axis Enhances Cisplatin-induced Apoptosis in Bladder Cancer Cells

OBJECTIVE

It has been reported that intrinsic apoptosis is associated with the progression of bladder cancer (BC). Recent evidence suggests that polyribonucleotide nucleotidyltransferase 1 (PNPT1) is a pivotal mediator involved in RNA decay and cell apoptosis. However, the regulation and roles of PNPT1 in bladder cancer remain largely unclear.

METHODS

The upstream miRNA regulators were predicted by in silico analysis. The expression levels of PNPT1 were evaluated by real-time PCR, Western blotting, and immunohistochemistry (IHC), while miR-183-5p levels were evaluated by qPCR in BC cell lines and tissues. In vitro and in vivo assays were performed to investigate the function of miR-183-5p and PNPT1 in apoptotic RNA decay and the tumorigenic capability of bladder cancer cells.

RESULTS

PNPT1 expression was decreased in BC tissues and cell lines. Overexpression of PNPT1 significantly promoted cisplatin-induced intrinsic apoptosis of BC cells, whereas depletion of PNPT1 potently alleviated these effects. Moreover, oncogenic miR-183-5p directly targeted the 3' UTR of PNPT1 and reversed the tumor suppressive role of PNPT1. Intriguingly, miR-183-5p modulated not only PNPT1 but also Bcl2 modifying factor (BMF) to inhibit the mitochondrial outer membrane permeabilization (MOMP) in BC cells.

CONCLUSION

Our results provide new insight into the mechanisms underlying intrinsic apoptosis in BC, suggesting that the miR-183-5p-PNPT1 regulatory axis regulates the apoptosis of BC cells and might represent a potential therapeutic avenue for the treatment of BC.

Methyltransferase-like 3 facilitates lung cancer progression by accelerating m6A methylation-mediated primary miR-663 processing and impeding SOCS6 expression

OBJECTIVE

Lung cancer (LC) remains a threatening health issue worldwide. Methyltransferase-like protein 3 (METTL3) is imperative in carcinogenesis via m6A modification of microRNAs (miRNAs). This study estimated the effect of METTL3 in LC by regulating m6A methylation-mediated pri-miR-663 processing.

METHODS

miR-663 expression in 4 LC cell lines and normal HBE cells was determined using RT-qPCR. A549 and PC9 LC cells selected for in vitro studies were transfected with miR-663 mimics or inhibitor. Cell viability, migration, invasion, proliferation, and apoptosis were detected by CCK-8, Transwell, EdU, and flow cytometry assays. The downstream target genes and binding sites of miR-663 were predicted via Starbase database and validated by dual-luciferase assay. LC cells were delivered with oe-METTL3/sh-METTL3. Crosslinking between METTL3 and DGCR8 was verified by co-immunoprecipitation. Levels of m6A, miR-663, and pri-miR-663 were measured by m6A dot blot assay and RT-qPCR. m6A modification of pri-miR-663 was verified by Me-RIP assay. Finally, the effects of METTL3 in vivo were ascertained by tumor xenograft in nude mice.

RESULTS

miR-663 was upregulated in LC cells, and miR-663 overexpression promoted cell proliferation, migration, invasion, and inhibited apoptosis, but miR-663 knockdown exerted the opposite effects. miR-663 repressed SOCS6 expression. SOCS6 overexpression annulled the promotion of miR-663 on LC cell growth. METTL3 bound to DGCR8, and METTL3 silencing elevated the levels of pri-miR-663 and m6A methylation-modified pri-miR-663, and suppressed miR-663 maturation and miR-663 expression. METTL3 facilitated tumor growth in mice through the miR-663/SOCS6 axis.

CONCLUSION

METTL3 promotes LC progression by accelerating m6A methylation-mediated pri-miR-663 processing and repressing SOCS6.

An Inflammation-Related Nine-Gene Signature to Improve Prognosis Prediction of Lung Adenocarcinoma

Background

A novel predictive model was rarely reported based on inflammation-related genes to explore clinical outcomes of lung adenocarcinoma (LUAD) patients.

Methods

Using TCGA database, we screened nine inflammation-related genes with a prognostic value, and LASSO regression was applied for model construction. The predictive value of the prognostic signature developed from inflammation-related genes was assessed by survival assays and multivariate assays. PCA and t-SNE analysis were performed to demonstrate clustering abilities of risk scores.

Results

Thirteen inflammation-related genes (BTG2, CCL20, CD69, DCBLD2, GPC3, IL7R, LAMP3, MMP14, NMUR1, PCDH7, PIK3R5, RNF144B, and TPBG) with prognostic values were finally identified. LASSO regression further screened nine candidates (BTG2, CCL20, CD69, IL7R, MMP14, NMUR1, PCDH7, RNF144B, and TPBG). Then, a prognostic prediction model using the above nine genes was constructed. A reliable clustering ability of risk score was demonstrated by PCA and t-SNE assays in 500 LUAD patients. The survival assays revealed that the overall survivals of the high-risk group were distinctly poorer than those of the low-risk group with 1-, 3-, and 5-year AUC values of 0.695, 0.666, and 0.694, respectively. Finally, multivariate assays demonstrated the scoring system as an independent prognostic factor for overall survival.

Conclusions

Our study shows that the signature of nine inflammation-related genes can be used as a prognostic marker for LUAD.

The miR-146b-5p promotes Ewing's sarcoma cells progression via suppressing the expression of BTG2

Ewing sarcoma (ES) is a malignant tumor that occurs mostly in children. However, the underlying mechanisms of ES are still unknown. Analyzing the results of two previous miRNA array reports, we found that miR-146b-5p might be an onco-miRNA in ES progression. To test this hypothesis, we detected the expression levels of miR-146b-5p by real-time PCR and observed the effects of miR-146b-5p on the progression of ES cells by CCK8 and transwell assays. Bioinformatics and luciferase assays were used to identify the target genes of miR-146b-5p. It showed that the expression levels of miR-146b-5p were upregulated in ES cell lines compared with human mesenchymal stem cells (MSCs). Up- or downregulation of miR-146b-5p in ES cell lines could effectively promote or block the proliferation, migration, and invasion of ES cells, respectively. Furthermore, we demonstrated that BTG2 was one of the target genes and mediated the effects of miR-146b-5p in ES cells. Interestingly, we also found that miR-146b-5p was partly involved in the anticancer effects of pemetrexed in ES cells. Our study revealed that miR-146b-5p affected the progression of ES by suppressing BTG2, which might shed light on anticancer drug development and ES treatment in the future.

MicroRNAs: Emerging oncogenic and tumor-suppressive regulators, biomarkers and therapeutic targets in lung cancer

Lung cancer is one of the most common solid tumors worldwide and the leading cause of cancer-related deaths, causing a devastating impact on human health. The clinical prognosis of lung cancer is usually restricted by delayed diagnosis and resistance to anticancer therapies. MicroRNAs, a range of small endogenous noncoding RNAs 22 nucleotides in length, have emerged as one of the most important players in cancer initiation and progression in recent decades. Current evidence reveals pivotal roles of microRNAs in regulating cell proliferation, migration, invasion and metastasis in lung cancer. An increasing number of preclinical and clinical studies have also explored the potential of microRNAs as promising biomarkers and new therapeutic targets for lung cancer. The current review summarizes the most recent progress on the functional mechanisms of microRNAs involved in lung cancer development and progression and further discusses the clinical application of miRNAs as putative therapeutic targets for molecular diagnosis and prognostic prediction in lung cancer.

The CCR4-NOT deadenylase complex safeguards thymic positive selection by down-regulating aberrant pro-apoptotic gene expression

A repertoire of T cells with diverse antigen receptors is selected in the thymus. However, detailed mechanisms underlying this thymic positive selection are not clear. Here we show that the CCR4-NOT complex limits expression of specific genes through deadenylation of mRNA poly(A) tails, enabling positive selection. Specifically, the CCR4-NOT complex is up-regulated in thymocytes before initiation of positive selection, where in turn, it inhibits up-regulation of pro-apoptotic Bbc3 and Dab2ip. Elimination of the CCR4-NOT complex permits up-regulation of Bbc3 during a later stage of positive selection, inducing thymocyte apoptosis. In addition, CCR4-NOT elimination up-regulates Dab2ip at an early stage of positive selection. Thus, CCR4-NOT might control thymocyte survival during two-distinct stages of positive selection by suppressing expression levels of pro-apoptotic molecules. Taken together, we propose a link between CCR4-NOT-mediated mRNA decay and T cell selection in the thymus.

Epigenetic alteration of mitochondrial biogenesis regulatory genes in arsenic exposed individuals (with and without skin lesions) and in skin cancer tissues: A case control study

Chronic arsenic toxicity has become a global concern due to its adverse pathophysiological outcome and carcinogenic potential. It is already established that arsenic induced reactive oxygen species alters mitochondrial functionality. Major regulatory genes for mitochondrial biogenesis, i.e., PGC1α, Tfam, NRF1and NRF2 are located in the nucleus. As a result, mitochondria-nucleus crosstalk is crucial for proper mitochondrial function. This previous hypothesis led us to investigateinvolvement of epigenetic alteration behindenhanced mitochondrial biogenesis in chronic arsenic exposure. An extensive case-control study was conducted with 390 study participants (unexposed, exposed without skin lesion, exposed with skin lesion and exposed skin tumour) from highly arsenic exposed areas ofWest Bengal, India. Methylation specific PCRrevealed significant promoter hypomethylation oftwo key biogenesis regulatory genes, PGC1αandTfam in arsenic exposed individuals and also in skin tumour tissues. Linear regression analysis indicated significant negative correlation between urinary arsenic concentration and promoter methylation status. Increased expression of biogenesis regulatory genes wasobtained by quantitative real-time PCR analysis. Moreover, altered mitochondrial fusion-fission regulatory gene expression was also observed in skin tumour tissues. miR663, having tumour suppressor gene like function was known to be epigenetically regulated through mitochondrial retrograde signal. Promoter hypermethylation with significantly decreased expression of miR663 was found in skin cancer tissues compared to non-cancerous control tissue. In conclusion, results indicated crucial role of epigenetic alteration in arsenic induced mitochondrial biogenesis and arsenical skin carcinogenesis for the first time. However, further mechanistic studies are necessary for detailed understanding of mitochondria-nucleus crosstalk in arsenic perturbation.

Metformin Increases the Chemosensitivity of Pancreatic Cancer Cells to Gemcitabine by Reversing EMT Through Regulation DNA Methylation of miR-663

Background

Pancreatic cancer is a devastating malignancy with poor prognosis. Metformin, a classic anti-diabetes drug, seems to improve survival of pancreatic cancer patients in some studies.

Methods

Cell counting kit-8 assay was used to detect the BxPC-3 and MIAPaCa-2 cell viability after treatment with gemcitabine only or with different concentrations of metformin. The methylation state and expression level of miR-663 were detected by methylation analysis and RT-PCR. Dual-luciferase reporter gene analysis, Western blot and RT-PCR were used to confirm the target of miR-663. Moreover, xenograft experiment was also performed to validate the role of metformin in chemosensitivity in vivo.

Results

We found that metformin increased the chemosensitivity of pancreatic cancer cells to gemcitabine, and epithelial-mesenchymal transition (EMT) progress caused by gemcitabine was suppressed by metformin. We further explored the possible molecular mechanisms and it was demonstrated that CpG islands of miR-663 were hypomethylated and relative expression level of miR-663 was up-regulated after treatment of metformin. miR-663, an important cancer suppressor miRNA, was confirmed to increase the chemosensitivity of pancreatic cancer cells by reversing EMT directly targeted TGF-β1. Moreover, we identified that metformin increased the chemosensitivity through up-regulating expression of miR-663.

Conclusion

We demonstrated that metformin increased the chemosensitivity of pancreatic cancer cells to gemcitabine by reversing EMT through regulation DNA methylation of miR-663.

Glycyrrhetinic Acid-Induced MiR-663a Alleviates Hepatic Stellate Cell Activation by Attenuating the TGF-β/Smad Signaling Pathway

Glycyrrhetinic acid (GA), a hydrolysate of glycyrrhizic acid from licorice root extract, has been used to treat liver fibrotic diseases. However, the molecular mechanism involved in the antifibrotic effects of GA remains unclear. The involvement of miR-663a and its roles in TGF-β-1-induced hepatic stellate cell (HSC) activation remains unclear. In this study, we investigated the roles of miR-663a in the activation of HSCs and the antifibrosis mechanism of GA. MiR-663a expression was downregulated in TGF-β-treated HSCs. The overexpression of miR-663a inhibited HSC proliferation. TGF-β-1was confirmed as a direct target gene of miR-663a. MiR-663a alleviated HSC activation, concomitant with decreased expression of α-smooth muscle actin (α-SMA), human α2 (I) collagen (COL1A2), TGF-β1, TGF-βRI, Smad4, p-Smad2, and p-Smad3. GA upregulated miR-663a expression and inhibited the TGF-β/Smad pathway in HSCs. Further studies showed that miR-663a inhibitor treatment reversed GA-mediated downregulation of TGF-β1, TGF-βRI, Smad4, p-Smad2, p-Smad3, α-SMA, and CoL1A2 in TGF-β1-treated HSCs. These results show that miR-663a suppresses HSC proliferation and activation and the TGF-β/Smad signaling pathway, highlighting that miR-663a can be utilized as a therapeutic target for hepatic fibrosis. GA inhibits, at least in part, HSC proliferation and activation via targeting the miR-663a/TGF-β/Smad signaling pathway.

Crosstalk of MicroRNAs and Oxidative Stress in the Pathogenesis of Cancer

Oxidative stress refers to an imbalance between reactive oxygen species (ROS) generation and body's capability to detoxify the reactive mediators or to fix the relating damage. MicroRNAs are considered to be important mediators that play essential roles in the regulation of diverse aspects of carcinogenesis. Growing studies have demonstrated that the ROS can regulate microRNA biogenesis and expression mainly through modulating biogenesis course, transcription factors, and epigenetic changes. On the other hand, microRNAs may in turn modulate the redox signaling pathways, altering their integrity, stability, and functionality, thus contributing to the pathogenesis of multiple diseases. Both ROS and microRNAs have been identified to be important regulators and potential therapeutic targets in cancers. However, the information about the interplay between oxidative stress and microRNA regulation is still limited. The present review is aimed at summarizing the current understanding of molecular crosstalk between microRNAs and the generation of ROS in the pathogenesis of cancer.

miR-1285-3p Controls Colorectal Cancer Proliferation and Escape from Apoptosis through DAPK2

MicroRNAs are tiny but powerful regulators of gene expression at the post-transcriptional level. Aberrant expression of oncogenic and tumor-suppressor microRNAs has been recognized as a common feature of human cancers. Colorectal cancer represents a major clinical challenge in the developed world and the design of innovative therapeutic approaches relies on the identification of novel biological targets. Here, we perform a functional screening in colorectal cancer cells using a library of locked nucleic acid (LNA)-modified anti-miRs in order to unveil putative oncogenic microRNAs whose inhibition yields a cytotoxic effect. We identify miR-1285-3p and further explore the effect of its targeting in both commercial cell lines and primary colorectal cancer stem cells, finding induction of cell cycle arrest and apoptosis. We show that DAPK2, a known tumor-suppressor, is a novel miR-1285 target and mediates both the anti-proliferative and the pro-apoptotic effects of miR-1285 depletion. Altogether, our findings uncover a novel oncogenic microRNA in colorectal cancer and lay the foundation for further studies aiming at the development of possible therapeutic strategies based on miR-1285 targeting.

Serum miR-663 expression and the diagnostic value in colorectal cancer

Colorectal cancer (CRC) is one of the most common digestive cancers leading to deaths worldwide. In this study, we aimed to investigate the diagnostic value of miR-663 in CRC. The expression of miR-663 was detected by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR). The association between miR-663 and clinical parameters of subjects was evaluated by chi-square test. Additionally, ROC (receiver operating characteristic) analysis was performed to evaluate the diagnostic role of miR-663 in CRC. The expression of miR-663 in CRC patients was significantly upregulated compared with benign colorectal disease patients and healthy controls (p < .01). Besides, the expression of miR-663 was significantly associated with tumour differentiation, invasion, lymph node metastasis and TNM stage (p < .05). The cutoff value of miR-663 was 1.31, and the corresponding sensitivity and specificity were 83.1% and 73.8%, respectively. In ROC analysis, the area under the curve (AUC) was 0.806, which indicated that miR-663 could act as an independent diagnostic biomarker for CRC. In conclusion, miR-663 was up-regulated in CRC patients and may be an effective biomarker for CRC diagnosis.

miR-663b promotes colorectal cancer progression by activating Ras/Raf signaling through downregulation of TNK1

MiR-663b has been demonstrated to be abnormally expressed in several cancer types and was involved in the progression of cancer. Although overexpression of miR-663b in colorectal cancer was observed, the role of miR-663b in colorectal cancer cells has not been identified yet. In this study, we analyzed expression of miR-663b in colorectal tumors and explored the molecular mechanism of miR-663b in colorectal cancer cells. MiR-663b was significantly overexpressed in colorectal tumors and cell lines. Downregulation of miR-663b inhibited cell proliferation and sphere forming ability in colorectal cancer cells. In addition, miR-663b downregulation inactivated Ras/Raf signaling activity and subsequently decreased YAP1 and CD44 expression in colorectal cancer cells. Using TargetScan software, TNK1, a negative regulator of Ras/Raf signaling, was predicted to be a target gene of miR-663b. Western blotting and RT-qPCR showed that TNK1 expression was negatively regulated by miR-663b. In addition, the direct binding of miR-663b to TNK1 mRNA was proved by dual luciferase reporter assay. Furthermore, downregulation of miR-663b inhibited colorectal cancer cell proliferation and stemness, which was reversed after siRNA-mediated silencing of TNK1. In conclusion, the current study revealed a pivotal role of miR-663b in the progression of colorectal cancer.

Transcriptomic Pattern of Genes Regulating Protein Response and Status of Mitochondrial Activity Are Related to Oocyte Maturational Competence-A Transcriptomic Study

This paper aims to identify and describe new genetic markers involved in the processes of protein expression and modification reflected in the change of mitochondrial activity before and after in vitro maturation of the oocyte. Porcine oocytes collected from the ovaries of slaughtered landrace gilts were subjected to the process of in vitro maturation. Transcriptomic changes in the expression profile of oocyte genes involved in response to hypoxia, the transmembrane protein receptor serine threonine kinase signaling pathway, the “transforming growth factor β receptor signaling pathway”, “response to protein stimulus”, and “response to organic substance” were investigated using microarrays. The expression values of these genes in oocytes was analyzed before (immature) and after (mature) in vitro maturation, with significant differences found. All the significantly altered genes showed downregulation after the maturation process. The most changed genes from these gene ontologies, FOS, ID2, VEGFA, BTG2, CYR61, ESR1, AR, TACR3, CCND2, CHRDL1, were chosen to be further validated, described and related to the literature. Additionally, the mitochondrial activity of the analyzed oocytes was measured using specific dyes. We found that the mitochondrial activity was higher before the maturation process. The analysis of these results and the available literature provides a novel insight on the processes that occur during in vitro oocyte maturation. While this knowledge may prove to be useful in further research of the procedures commonly associated with in vitro fertilization procedures, it serves mostly as a basic reference for further proteomic, in vivo, and clinical studies that are necessary to translate it into practical applications.

Emerging microRNA biomarkers for colorectal cancer diagnosis and prognosis

MicroRNAs (miRNAs) are one abundant class of small, endogenous non-coding RNAs, which regulate various biological processes by inhibiting expression of target genes. miRNAs have important functional roles in carcinogenesis and development of colorectal cancer (CRC), and emerging evidence has indicated the feasibility of miRNAs as robust cancer biomarkers. This review summarizes the progress in miRNA-related research, including study of its oncogene or tumour-suppressor roles and the advantages of miRNA biomarkers for CRC diagnosis, treatment and recurrence prediction. Along with analytical technique improvements in miRNA research, use of the emerging extracellular miRNAs is feasible for CRC diagnosis and prognosis.

MicroRNA‑663 inhibits the proliferation and invasion of clear cell renal cell carcinoma cells by directly targeting PAK4

Accumulating evidence has demonstrated that microRNAs (miRNAs) are key gene regulators and are abnormally expressed in clear cell renal cell carcinoma (ccRCC). The dysregulation of miRNAs has been implicated in the initiation and progression of ccRCC. Therefore, identification of ccRCC‑associated miRNAs may facilitate the determination of promising therapeutic targets for anti‑cancer treatment. In the present study, miRNA‑663 (miR‑663) expression was downregulated in ccRCC tissues and cell lines. Functional experiments suggested that restoration of miR‑663 expression inhibited the proliferation and invasion of ccRCC cells. In addition, p21 activated kinase 4 (PAK4) was validated as a direct target of miR‑663 in ccRCC cells. PAK4 was upregulated in ccRCC tissues, and the expression level of PAK4 was inversely correlated with the miR‑663 expression level. PAK4 restoration partially attenuated the suppressive roles of miR‑663 overexpression on the proliferation and invasion of ccRCC cells. The present results provide novel insight into the mechanism underlying the occurrence and development of ccRCC, suggesting that the miR‑663/PAK4 axis may be a novel therapeutic target for treatment of patients with ccRCC.

MiR-663, a MicroRNA Linked with Inflammation and Cancer That Is under the Influence of Resveratrol

Resveratrol (trans-3,5,4′-trihydroxystilbene, RSV) is a non-flavonoid dietary polyphenol with antioxidant, anti-inflammatory and anti-cancer properties that is primarily found in red berries. While RSV displays many beneficial effects in vitro, its actual effects in vivo or in animal models remain passionately debated. Recent publications suggest that RSV pleiotropic effects could arise from its capability to regulate the expression and activity of microRNAs, short regulators themselves capable of regulating up to several hundreds of target genes. In particular, RSV increases microRNA miR-663 expression in different human cell lines, suggesting that at least some of its multiple beneficial properties are through the modulation of expression of this microRNA. Indeed, the expression of microRNA miR-663 is reduced in certain cancers where miR-663 is considered to act as a tumor suppressor gene, as well as in other pathologies such as cardiovascular disorders. Target of miR-663 include genes involved in tumor initiation and/or progression as well as genes involved in pathologies associated with chronic inflammation. Here, we review the direct and indirect effects of RSV on the expression of miR-663 and its target transcripts, with emphasise on TGFβ1, and their expected health benefits, and argue that elucidating the molecular effects of different classes of natural compounds on the expression of microRNAs should help to identify new therapeutic targets and design new treatments.

Micro-Economics of Apoptosis in Cancer: ncRNAs Modulation of BCL-2 Family Members

In the last few years, non-coding RNAs (ncRNAs) have been a hot topic in cancer research. Many ncRNAs were found to regulate the apoptotic process and to play a role in tumor cell resistance to treatment. The apoptotic program is on the frontline as self-defense from cancer onset, and evasion of apoptosis has been classified as one of the hallmarks of cancer responsible for therapy failure. The B-cell lymphoma 2 (BCL-2) family members are key players in the regulation of apoptosis and mediate the activation of the mitochondrial death machinery in response to radiation, chemotherapeutic agents and many targeted therapeutics. The balance between the pro-survival and the pro-apoptotic BCL-2 proteins is strictly controlled by ncRNAs. Here, we highlight the most common mechanisms exerted by microRNAs, long non-coding RNAs and circular RNAs on the main mediators of the intrinsic apoptotic cascade with particular focus on their significance in cancer biology.