MicroRNA-497 targets insulin-like growth factor 1 receptor and has a tumour suppressive role in human colorectal cancer

Mechanism of 5-fluorouracil induced resistance and role of piperine and curcumin as chemo-sensitizers in colon cancer

Among cancer-related deaths worldwide, colorectal cancer ranks second, accounting for 1.2% of deaths in those under 50 years and 0.6% of deaths in those between 50 and 54 years. The anticancer drug 5-fluorouracil is widely used to treat colorectal cancer. Due to a better understanding of the drug's mechanism of action, its anticancer activity has been increased through a variety of therapeutic alternatives. Clinical use of 5-FU has been severely restricted due to drug resistance. The chemoresistance mechanism of 5-FU is challenging to overcome because of the existence of several drug efflux transporters, DNA repair enzymes, signaling cascades, classical cellular processes, cancer stem cells, metastasis, and angiogenesis. Curcumin, a potent phytocompound derived from Curcuma longa, functions as a nuclear factor (NF)-κB inhibitor and sensitizer to numerous chemotherapeutic drugs. Piperine, an alkaloid found in Piper longum, inhibits cancer cell growth, causing cell cycle arrest and apoptosis. This review explores the mechanism of 5-FU-induced chemoresistance in colon cancer cells and the role of curcumin and piperine in enhancing the sensitivity of 5-FU-based chemotherapy. CLINICAL TRIAL REGISTRATION: Not applicable.

Epigenetic regulation of androgen dependent and independent prostate cancer

Prostate cancer is one of the most common malignancies among men worldwide. Besides genetic alterations, epigenetic modulations including DNA methylation, histone modifications and miRNA mediated alteration of gene expression are the key driving forces for the prostate tumor development and cancer progression. Aberrant expression and/or the activity of the epigenetic modifiers/enzymes, results in aberrant expression of genes involved in DNA repair, cell cycle regulation, cell adhesion, apoptosis, autophagy, tumor suppression and hormone response and thereby disease progression. Altered epigenome is associated with prostate cancer recurrence, progression, aggressiveness and transition from androgen-dependent to androgen-independent phenotype. These epigenetic modifications are reversible and various compounds/drugs targeting the epigenetic enzymes have been developed that are effective in cancer treatment. This chapter focuses on the epigenetic alterations in prostate cancer initiation and progression, listing different epigenetic biomarkers for diagnosis and prognosis of the disease and their potential as therapeutic targets. This chapter also summarizes different epigenetic drugs approved for prostate cancer therapy and the drugs available for clinical trials.

The Critical Function of microRNAs in Developing Resistance against 5- Fluorouracil in Cancer Cells

Although there have been significant advancements in cancer treatment, resistance and recurrence in patients make it one of the leading causes of death worldwide. 5-fluorouracil (5-FU), an antimetabolite agent, is widely used in treating a broad range of human malignancies. The cytotoxic effects of 5-FU are mediated by the inhibition of thymidylate synthase (TYMS/TS), resulting in the suppression of essential biosynthetic activity, as well as the misincorporation of its metabolites into RNA and DNA. Despite its huge benefits in cancer therapy, the application of 5-FU in the clinic is restricted due to the occurrence of drug resistance. MicroRNAs (miRNAs) are small, non-coding RNAs that act as negative regulators in many gene expression processes. Research has shown that changes in miRNA play a role in cancer progression and drug resistance. This review examines the role of miRNAs in 5-FU drug resistance in cancers.

Common susceptibility variants of KDR and IGF-1R are associated with poststroke depression in the Chinese population

Background

Depression, one of the most frequent complications after stroke, increases the disease's burden and physical disability. Poststroke depression (PSD) is a multifactorial disease with genetic, environmental and biological factors involved in its occurrence. Genetic studies on PSD to date have mainly focused on the monoamine system and brain-derived neurotrophic factors. However, understanding is still limited about the influence of the single nucleotide polymorphism (SNP) of other neurotrophic factors on PSD.

Aims

The present study aimed to investigate the relationship between seven vascular endothelial growth factor (VEGF) family gene variants that occur with PSD.

Methods

A multicentre candidate gene study from five hospitals in Jiangsu Province from June 2013 to December 2014 involved 121 patients with PSD and 131 patients with non-PSD. Demographic characteristics and neuropsychological assessments were collected. The χ² test was used to evaluate categorical variables, while the independent t-test was applied to continuous variables. SNPs in seven genes (VEGFA, VEGFB, KDR, FLT-1, IGF-1, IGF-1R and PlGF) were genotyped. Single-marker association for PSD was analysed by χ² tests and logistic regression using SPSS and PLINK software.

Results

Patients with PSD included more women and those with lower education levels, lower body mass indexes, lower Mini-Mental State Examination scores, and higher scores on the 17-item Hamilton Depression Rating Scale than non-PSD patients. Ninety-two SNPs with seven genes were genotyped and passed quality control. The rs7692791 CC genotypes, the C allele of KDR and the rs9282715 T allele of IGF-1R increased the risk for PSD (χ²=7.881, p=0.019; χ²=4.259, p=0.039; χ²=4.222, p=0.040, respectively). In addition, the SNP rs7692791 of KDR was significantly associated with PSD by the logistic regression of an additive model (p=0.015, OR=9.584, 95% CI: 1.549 to 59.31).

Conclusions

Patients with rs7692791 C allele carriers or the CC genotype of KDR and the rs9282715 T allele of IGF-1R may have PSD susceptibility. Findings such as these may help clinicians to identify the high-risk population for PSD earlier and, thus, enable them to provide more timely interventions.

Trial registration number

ChiCTR-OCH-13003133.

Promotion or remission: a role of noncoding RNAs in colorectal cancer resistance to anti-EGFR therapy

Anti-epidermal-growth-factor-receptor (EGFR) monoclonal antibodies (mAbs) are of great significance for RAS and BRAF wild-type metastatic colorectal cancer (mCRC) patients. However, the generation of primary and secondary resistance to anti-EGFR mAbs has become an important factor restricting its efficacy. Recent studies have revealed that non-coding RNAs (ncRNAs), especially long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are implicated in anti-EGFR antibodies resistance, affecting the sensitivity of CRC cells to Cetuximab and Panitumumab. This paper briefly reviewed the research advance of the expression, signaling network and functional mechanism of ncRNAs related to anti-EGFR mAbs resistance in CRC, as well as their relationship with clinical prognosis and the possibility of therapeutic targets. In addition, some ncRNAs that are involved in the regulation of signaling pathways or genes related to anti-EGFR resistance, but need to be further verified by resistance experiments were also included in this review, thereby providing more ideas and basis for ncRNAs as CRC prognostic markers and anti-EGFR therapy sensitizers. Video Abstract.

The Insulin-like Growth Factor System and Colorectal Cancer

Insulin-like growth factors (IGFs) are peptides which exert mitogenic, endocrine and cytokine activities. Together with their receptors, binding proteins and associated molecules, they participate in numerous pathophysiological processes, including cancer development. Colorectal cancer (CRC) is a disease with high incidence and mortality rates worldwide, whose etiology usually represents a combination of the environmental and genetic factors. IGFs are most often increased in CRC, enabling excessive autocrine/paracrine stimulation of the cell growth. Overexpression or increased activation/accessibility of IGF receptors is a coinciding step which transmits IGF-related signals. A number of molecules and biochemical mechanisms exert modulatory effects shaping the final outcome of the IGF-stimulated processes, frequently leading to neoplastic transformation in the case of irreparable disbalance. The IGF system and related molecules and pathways which participate in the development of CRC are the focus of this review.

Contribution of MicroRNAs in Chemoresistance to Cisplatin in the Top Five Deadliest Cancer: An Updated Review

Cisplatin (DDP) is a well-known anticancer drug used for the treatment of numerous human cancers in solid organs, including bladder, breast, cervical, head and neck squamous cell, ovarian, among others. Its most important mode of action is the DNA-platinum adducts formation, inducing DNA damage response, silencing or activating several genes to induce apoptosis; these mechanisms result in genetics and epigenetics modifications. The ability of DDP to induce tumor cell death is often challenged by the presence of anti-apoptotic regulators, leading to chemoresistance, wherein many patients who have or will develop DDP-resistance. Cancer cells resist the apoptotic effect of chemotherapy, being a problem that severely restricts the successful results of treatment for many human cancers. In the last 30 years, researchers have discovered there are several types of RNAs, and among the most important are non-coding RNAs (ncRNAs), a class of RNAs that are not involved in protein production, but they are implicated in gene expression regulation, and representing the 98% of the human genome non-translated. Some ncRNAs of great interest are long ncRNAs, circular RNAs, and microRNAs (miRs). Accumulating studies reveal that aberrant miRs expression can affect the development of chemotherapy drug resistance, by modulating the expression of relevant target proteins. Thus, identifying molecular mechanisms underlying chemoresistance development is fundamental for setting strategies to improve the prognosis of patients with different types of cancer. Therefore, this review aimed to identify and summarize miRs that modulate chemoresistance in DDP-resistant in the top five deadliest cancer, both in vitro and in vivo human models.

A functional screen with metformin identifies microRNAs that regulate metabolism in colorectal cancer cells

Metformin inhibits oxidative phosphorylation and can be used to dissect metabolic pathways in colorectal cancer (CRC) cells. CRC cell proliferation is inhibited by metformin in a dose dependent manner. MicroRNAs that regulate metabolism could be identified by their ability to alter the effect of metformin on CRC cell proliferation. An unbiased high throughput functional screen of a synthetic micoRNA (miRNA) library was used to identify miRNAs that impact the metformin response in CRC cells. Experimental validation of selected hits identified miRNAs that sensitize CRC cells to metformin through modulation of proliferation, apoptosis, cell-cycle and direct metabolic disruption. Among eight metformin sensitizing miRNAs identified by functional screening, miR-676-3p had both pro-apoptotic and cell cycle arrest activity in combination with metformin, whereas other miRNAs (miR-18b-5p, miR-145-3p miR-376b-5p, and miR-718) resulted primarily in cell cycle arrest when combined with metformin. Investigation of the combined effect of miRNAs and metformin on CRC cell metabolism showed that miR-18b-5p, miR-145-3p, miR-376b-5p, miR-676-3p and miR-718 affected glycolysis only, while miR-1181 only regulated CRC respiration. MicroRNAs can sensitize CRC cells to the anti-proliferative effects of metformin. Identifying relevant miRNA targets may enable the design of innovative therapeutic strategies.

Association of B-cell lymphoma 2/microRNA-497 gene expression ratio score with metastasis in patients with colorectal cancer: A propensity-matched cohort analysis

Background

Deregulated microRNAs (miRs) significantly impact cancer development and progression. Our in silico analysis revealed that miR‐497 and its target gene B‐cell lymphoma‐2 (BCL2) could be related to poor cancer outcomes.

Purpose

To investigate the BCL2/miRNA‐497 expression ratio in colorectal cancer (CRC) and explore its association with the clinicopathological characteristics and CRC prognosis.

Methods

Archived samples from 106 CRC patients were enrolled. MiR‐497 and BCL2 gene expressions were detected by Taq‐Man Real‐Time quantitative polymerase chain reaction in propensity‐matched metastatic and nonmetastatic cohorts after elimination of confounder bias.

Results

B‐cell lymphoma‐2 gene was upregulated in metastatic samples (median = 1.16, 95%CI = 1.09–1.60) compared to nonmetastatic (median = 1.02, 95%CI = 0.89–1.25, p < 0.001). In contrast, lower levels of miR‐495 were detected in specimens with distant metastasis (median = 0.05, 95%CI = 0.04–0.20) than nonmetastatic samples (median = 0.54, 95%CI = 0.47–0.58, p < 0.001). Estimated BCL2/miR‐497 ratio yielded a significant differential expression between the two cohort groups. Higher scores were observed in metastasis group (median = 1.39, 95%CI = 0.9–1.51) than nonmetastatic patients (median = 0.29, 95%CI = 0.19–0.39, p < 0.001). Receiver operating characteristic curve analysis showed BCL2/miR‐497 ratio score to have the highest predictive accuracy for metastasis at presentation. The area under the curve was 0.90 (95%CI = 0.839–0.964, p < 0.001) at cut‐off of >0.525, with high sensitivity 81.1% (95%CI = 68.6%–89.4%) and specificity 92.5% (95%CI = 82.1%–97.0%). Also, the ratio score was negatively correlated with disease‐free survival (r = −0.676, p < 0.001) and overall survival times (r = −0.650, p < 0.001). Kaplan–Meier curves showed lower survival rates in cohorts with high‐score compared to low‐score patients.

Conclusion

The BCL2/miR497 expression ratio is associated with poor CRC prognosis in terms of metastasis and short survival.

Small molecules with huge impacts: the role of miRNA-regulated PI3K pathway in human malignancies

Along with evolution, a considerable number of signaling cascades have evolved within cells to meet their multifaceted needs. Among transmitting molecules, phosphoinositide 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR) have teamed up to build a signaling axis that effectively regulates various cellular processes including cell proliferation and migration. Given the extensive output of the PI3K/Akt/mTOR signaling axis, its aberrancy could subsequently lead to the formation of a wide range of human cancers spanning from hematologic malignancies to different types of solid tumors. Despite the high frequency of the PI3K pathway over-activation in most malignancies, mutations in the DNA sequence are not equally common. Such incompatibility sheds light on the possible effects of post-translational modification mechanisms that may take control of this pathway, some of the most important ones of which are through microRNAs (miRNAs or miRs). The present review is designed to take off the veil from the regulatory role of these small non-coding RNAs on the PI3K/Akt/mTOR signaling axis in carcinogenesis.

microRNAs: Small molecules with a large impact on colorectal cancer

Colorectal cancer (CRC) accounts for one of the main cancer-related mortality and morbidity worldwide. The molecular mechanisms of CRC development have been broadly investigated and, over the last decade, it has become evident that aberrant transcription of microRNAs (miRNAs), a class of small, noncoding RNA molecules, has a significant role in the inception and promotion of CRC. In the involved tissues of CRC, the transcription profile of miRNAs is modulated, and their expression templates are related with prognosis, diagnosis, and treatment outcomes. Here, in the current review, we attempted to discuss the latest information regarding the aberrantly expressed miRNAs in CRC and the advantages of utilizing miRNAs as biomarkers for early diagnosis and prognosis of CRC as well as potential therapeutic application. The effect of miRNAs involved in various signaling pathways, primarily p53, EGFR, Wnt, and TGF-β pathways, was clarified.

The Molecular Networks of microRNAs and Their Targets in the Drug Resistance of Colon Carcinoma

Simple Summary

We systematically reviewed the recent scientific publications describing the role of microRNAs in the regulation of drug resistance in colon cancer. To clarify the intricate web of resulting genetic and biochemical interactions, we used a machine learning approach aimed at creating: (i) networks of validated miRNA/target interactions involved in drug resistances and (ii) drug-centric networks, from which we identified the major clusters of proteins affected by drugs used in the treatment of colon cancer. Finally, to facilitate a high-level interpretation of these molecular interactions, we determined the cellular pathways related with drug resistance and regulated by the miRNAs in colon cancer.

Abstract

Drug resistance is one of the major forces driving a poor prognosis during the treatment and progression of human colon carcinomas. The molecular mechanisms that regulate the diverse processes underlying drug resistance are still under debate. MicroRNAs (miRNAs) are a subgroup of non-coding RNAs increasingly found to be associated with the regulation of tumorigenesis and drug resistance. We performed a systematic review of the articles concerning miRNAs and drug resistance in human colon cancer published from 2013 onwards in journals with an impact factor of 5 or higher. First, we built a network with the most studied miRNAs and targets (as nodes) while the drug resistance/s are indicated by the connections (edges); then, we discussed the most relevant miRNA/targets interactions regulated by drugs according to the network topology and statistics. Finally, we considered the drugs as nodes in the network, to allow an alternative point of view that could flow through the treatment options and the associated molecular pathways. A small number of microRNAs and proteins appeared as critically involved in the most common drugs used for the treatment of patients with colon cancer. In particular, the family of miR-200, miR34a, miR-155 and miR-17 appear as the most relevant microRNAs. Thus, regulating these miRNAs could be useful for interfering with some drug resistance mechanisms in colorectal carcinoma.

The Expression of Circulating miR-497 and Metadherin in Hepatocellular Carcinoma: Relation to the Tumor Characteristics and Patients' Survival

Objectives: This study aimed to evaluate the prognostic significance and relationship of miR-497 and metadherin to hepatocellular carcinoma (HCC) tumor characteristics and patients’ survival. Methods: This study enrolled 120 (60 HCC patients and 60 healthy) subjects. Serum miR-497 and metadherin mRNA relative expression were analyzed by real-time quantitative reverse transcription polymerase chain reaction. The overall survival (OS) of HCC patients was assessed using the Kaplan–Meier curve and log-rank test. Results: Serum miR-497 showed statistically significant downregulation in HCC patients compared to controls (p < 0.001). Serum metadherin mRNA relative expression was significantly upregulated in HCC patients compared to controls (p < 0.001). Both serum miR-497 and metadherin mRNA expression were significantly associated with the number of tumor foci (p = 0.028 and 0.001, respectively), tumor size (p = 0.022 and <0.001, respectively), nodal metastasis (p = 0.003 and 0.003, respectively), distant metastasis (p = 0.003 and 0.003, respectively), vascular invasion (p = 0.040 and <0.001, respectively), and BCLC staging (p = 0.043 and 0.004, respectively). The overall survival was lower in patients with low miR-497 expression (p = 0.046) and in patients with high metadherin expression (p < 0.001). Conclusions: The expression levels of miR-497 showed downregulation in HCC patients, but metadherin expression showed upregulation. Both markers were inversely related and closely correlated with tumor characteristics and patients’ survival.

miR-497 inhibits proliferation and invasion in triple-negative breast cancer cells via YAP1

MicroRNA (miR)-497 has been reported as a tumor suppressor in various cancer types. Nonetheless, the regulation of triple-negative breast cancer (TNBC) by miR-497 remains poorly understood. The present study aimed to investigate the potential function and mechanism of miR-497 in TNBC. A total of 36 TNBC and matched non-cancerous tissue samples were collected for analysis. Reverse transcription-quantitative PCR was performed to detect the miR-497 levels in TNBC tissue. The association between miR-497 expression, clinical characteristics and survival was then analyzed. To investigate the role of miR-497 in TNBC, MTT, colony formation, Transwell invasion, cell cycle and cell apoptosis assays were conducted following transfection of miR-497 mimics into the MDA-MB-231 and MDA-MB-468 cell lines. Luciferase reporter assays and western blot analysis were used to confirm the regulation of a putative target of miR-497. The results indicated that the expression of miR-497 was downregulated in the TNBC specimens. Further analysis demonstrated that the expression of miR-497 was downregulated in patients with advanced TNBC stages and that low miR-497 was associated with poor prognosis in patients with TNBC. Transfection of miR-497 mimics inhibited TNBC cell proliferation and increased cell apoptosis in MDA-MB-231 and MDA-MB-468 cells. Moreover, cell migration was inhibited following overexpression of miR-497, which also led to the arrest of the breast cancer cells in the G₀/G₁ phase of the cell cycle. Yes-associated protein 1 (YAP1), a critical molecule in the Hippo pathway, was identified as a target of miR-497. Notably, the protein and mRNA expression levels of YAP1 in MDA-MB-231 and MDA-MB-468 cells were downregulated following overexpression of miR-497. Overall, the findings of the present study indicated that miR-497 inhibited TNBC cell proliferation and migration and induced cell apoptosis by negatively regulating YAP1 expression. Thus, targeting miR-497 may represent a potential strategy for the treatment of TNBC.

Plasma Extracellular Vesicle miRNAs Can Identify Lung Cancer, Current Smoking Status, and Stable COPD

Lung cancer remains the leading cause of cancer related mortality worldwide. We aimed to test whether a simple blood biomarker (extracellular vesicle miRNAs) can discriminate between cases with and without lung cancer.

METHODS

plasma extracellular vesicles (EVs) were isolated from four cohorts (n = 20 in each): healthy non-smokers, healthy smokers, lung cancer, and stable COPD participants. EV miRNA expression was evaluated using the miRCURY LNA miRNA Serum/Plasma assay for 179 specific targets. Significantly dysregulated miRNAs were assessed for discriminatory power using ROC curve analysis.

RESULTS

15 miRNAs were differentially expressed between lung cancer and healthy non-smoking participants, with the greatest single miRNA being miR-205-5p (AUC 0.850), improving to AUC 0.993 in combination with miR-199a-5p. Moreover, 26 miRNAs were significantly dysregulated between lung cancer and healthy smoking participants, with the greatest single miRNA being miR-497-5p (AUC 0.873), improving to AUC 0.953 in combination with miR-22-5p; 14 miRNAs were significantly dysregulated between lung cancer and stable COPD participants, with the greatest single miRNA being miR-27a-3p (AUC 0.803), with two other miRNAs (miR-106b-3p and miR-361-5p) further improving discriminatory power (AUC 0.870).

CONCLUSION

this case control study suggests miRNAs in EVs from plasma holds key biological information specific for lung cancer and warrants further prospective assessment.

CircRNAs: role in human diseases and potential use as biomarkers

Circular RNAs (circRNAs) are a class of endogenous RNAs characterized by a covalent loop structure. In comparison to other types of RNAs, the abundance of circRNAs is relatively low but due to the circular configuration, their stability is very high. In addition, circRNAs display high degree of tissue specificity. The sponging activity of circRNAs toward microRNAs is the best-described mode of action of circRNAs. However, the ability of circRNAs to bind with specific proteins, as well as to encode short proteins, propose alternative functions. This review introduces the biogenesis of circRNAs and summarizes the roles played by circRNAs in human diseases. These include examples of their functional roles in several organ-specific cancers, such as head and neck and breast and lung cancers. In addition, we review potential functions of circRNAs in diabetes, cardiovascular, and neurodegenerative diseases. Recently, a growing number of studies have demonstrated involvement of circRNAs in a wide spectrum of signaling molecular pathways, but at the same time many different and controversial views on circRNAs role and function are emerging. We conclude by offering cellular homeostasis generated by networks comprising circular RNAs, other non-coding RNAs and RNA-binding proteins. Accordingly, it is predictable that circRNAs, due to their highly stable nature and remarkable tissue specificity, will emerge as reliable biomarkers of disease course and treatment efficacy.

Non-coding RNAs related to angiogenesis in gynecological cancer

Gynecological cancer affects the female reproductive system, including ovarian, uterine, endometrial, cervical, vulvar, and vaginal tumors. Non-coding RNAs (ncRNAs), and in particular microRNAs, function as regulatory molecules, which can control gene expression in a post-transcriptional manner. Normal physiological processes like cellular proliferation, differentiation, and apoptosis, and pathological processes such as oncogenesis and metastasis are regulated by microRNAs. Numerous reports have shown a direct role of microRNAs in the modulation of angiogenesis in gynecological cancer, via targeting pro-angiogenic factors and signaling pathways. Understanding the molecular mechanism involved in the regulation of angiogenesis by microRNAs may lead to new treatment options. Recently the regulatory role of some long non-coding RNAs in gynecological cancer has also been explored, but the information on this function is more limited. The aim of this article is to explore the pathways responsible for angiogenesis, and to what extent ncRNAs may be employed as biomarkers or therapeutic targets in gynecological cancer.

MicroRNA-497 Reduction and Increase of Its Family Member MicroRNA-424 Lead to Dysregulation of Multiple Inflammation Related Genes in Synovial Fibroblasts With Rheumatoid Arthritis

Objectives

Mounting evidence has demonstrated that microRNAs (miRNAs) participate in rheumatoid arthritis (RA). The role of highly conserved miR-15/107 family in RA has not been clarified yet, and hence investigated in this study.

Methods

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to evaluate the expression of miRNAs and genes. Cell counting kit 8 (CCK-8) and FACS were used to detect proliferation and apoptosis. Protein expression was detected by using Western blotting. mRNA deep sequencing and cytokine antibody array were used to analyze differentially expressed genes, signaling pathways and cytokines.

Results

The expression of miR-15a, miR-103, miR-497, and miR-646 was found decreased, while miR-424 increased in RA patients. MiR-424 and miR-497 were further investigated and the results showed that they could regulate the expression of multiple genes in rheumatoid arthritis synovial fibroblast (RASF) and affect signaling pathways. At the protein level, miR-497 mimic altered all the selected inflammation-related genes while miR-424 inhibitor only affected part of genes. MiR-497 mimic, rather than miR-424 inhibitor, had significant effects on proliferation and apoptosis of RASF. DICER1 was found to positively regulate the expression of miR-424 and miR-497, while DICER1 was also negatively regulated by miR-424. The increase of miR-424 could reduce miR-497 expression, thus forming a loop, which facilitated explaining the dysregulated miR-424 and miR-497 in RA.

Conclusion

The miR-424 and miR-497 of miR-15/107 family affect cell proliferation and apoptosis in RA, and the proposed miR-424-DICER1-miR-497 feedback loop provides a novel insight into regulating miRNA expression and a candidate target for controlling RA.

Role of the IGF-1 Axis in Overcoming Resistance in Breast Cancer

Over the last two decades, many studies have demonstrated that the insulin-like growth factor-1 (IGF-1) is involved in a number of patho-physiological processes, as well as in the development of different types of solid tumors, including breast cancer (BC). Preclinical and clinical data showed that IGF-1 receptor (R) is overexpressed and hyper-phosphorylated in several subtypes of BCs. The central implications of this pathway in tumor cell proliferation and metastasis make it an important therapeutic target. Moreover, the IGF-1 axis has shown strong interconnection with estrogen regulation and endocrine therapy, suggesting a possible solution to anti-estrogen resistance. IGF-1R might also interfere with other pivotal therapeutic strategies, such as anti HER2 treatments and mTOR inhibitors; several clinical trials are ongoing evaluating the role of IGF-1R inhibition in modulating resistance mechanisms to target therapies. Our aim is to offer an overview of the most recent and significant field of application of IGF-1 inhibitors and relevant therapeutic strategies, weighing their possible future impact on clinical practice.

The Interplay Between Non-coding RNAs and Insulin-Like Growth Factor Signaling in the Pathogenesis of Neoplasia

The insulin-like growth factors (IGFs) are polypeptides with similar sequences with insulin. These factors regulate cell growth, development, maturation, and aging via different processes including the interplay with MAPK, Akt, and PI3K. IGF signaling participates in the pathogenesis of neoplasia, insulin resistance, diabetes mellitus, polycystic ovarian syndrome, cerebral ischemic injury, fatty liver disease, and several other conditions. Recent investigations have demonstrated the interplay between non-coding RNAs and IGF signaling. This interplay has fundamental roles in the development of the mentioned disorders. We designed the current study to search the available data about the role of IGF-associated non-coding RNAs in the evolution of neoplasia and other conditions. As novel therapeutic strategies have been designed for modification of IGF signaling, identification of the impact of non-coding RNAs in this pathway is necessary for the prediction of response to these modalities.

Network and Pathway-Based Integrated Analysis Identified a Novel "rs28457673-miR-15/16/195/424/497 Family-IGF1R-MAPK Signaling Pathway" Axis Associated With Post-stroke Depression

Single-nucleotide polymorphisms (SNPs) of microRNA (miRNA) (miRSNP) are SNPs located on miRNA genes or miRNA target sites, which have been supposed to be involved in the development of central nervous system diseases by interfering with miRNA-mediated regulatory functions. However, the association of miRSNP with post-stroke depression (PSD) has not been well-investigated. In this study, we collected 54 PSD risk genes via manual literature-mining and integrated PSD-related risk pathways based on multiple public databases. Furthermore, we systematically screened candidate functional miRSNPs for PSD and integrated a miRSNP-based PSD-associated pathway network, which included 99 miRNAs that target 12 PSD risk pathways. We also reviewed the association between three risk pathways and PSD pathogenetic mechanism thoroughly. Combining literature mining and network analysis, our results proposed an underlying mechanism of "miRSNP → miRNA → risk gene → pathway" axis effects on PSD pathogenesis, especially for rs28457673 (miR-15/16/195/424/497 family) → IGF1R → hsa04010 (MAPK signaling pathway). Our studies revealed a functional role in genetic modifier at the system level in the pathogenesis of PSD, which might provide further information for the miRSNP studies in PSD.

GH and IGF System: The Regulatory Role of miRNAs and lncRNAs in Cancer

Growth hormone (GH) and the insulin-like growth factor (IGF) system are involved in many biological processes and have growth-promoting actions regulating cell proliferation, differentiation, apoptosis and angiogenesis. A recent chapter in epigenetics is represented by microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) which regulate gene expression. Dysregulated miRNAs and lncRNAs have been associated with several diseases including cancer. Herein we report the most recent findings concerning miRNAs and lncRNAs regulating GH and the IGF system in the context of pituitary adenomas, osteosarcoma and colorectal cancer, shedding light on new possible therapeutic targets. Pituitary adenomas are increasingly common intracranial tumors and somatotroph adenomas determine supra-physiological GH secretion and cause acromegaly. Osteosarcoma is the most frequent bone tumor in children and adolescents and was reported in adults who were treated with GH in childhood. Colorectal cancer is the third cancer in the world and has a higher prevalence in acromegalic patients.

MicroRNA-Assisted Hormone Cell Signaling in Colorectal Cancer Resistance

Despite substantial progress in cancer therapy, colorectal cancer (CRC) is still the third leading cause of cancer death worldwide, mainly due to the acquisition of resistance and disease recurrence in patients. Growing evidence indicates that deregulation of hormone signaling pathways and their cross-talk with other signaling cascades inside CRC cells may have an impact on therapy resistance. MicroRNAs (miRNAs) are small conserved non-coding RNAs thatfunction as negative regulators in many gene expression processes. Key studies have identified miRNA alterations in cancer progression and drug resistance. In this review, we provide a comprehensive overview and assessment of miRNAs role in hormone signaling pathways in CRC drug resistance and their potential as future targets for overcoming resistance to treatment.

Dissecting miRNA signature in colorectal cancer progression and metastasis

Colorectal cancer (CRC) is the third most common cancer and leading cause of cancer related deaths worldwide. Despite recent advancements in surgical and molecular targeted therapies that improved the therapeutic efficacy in CRC, the 5 years survival rate of CRC patients still remains frustratingly poor. Accumulated evidences indicate that microRNAs (miRNAs) play a crucial role in the progression and metastasis of CRC. Dysregulated miRNAs are closely associated with cancerous phenotypes (e.g. enhanced proliferative and invasive ability, evasion of apoptosis, cell cycle aberration, and promotion of angiogenesis) by regulating their target genes. In this review, we provide an updated overview of tumor suppressive and oncogenic miRNAs, circulatory miRNAs, and the possible causes of dysregulated miRNAs in CRC. In addition, we discuss the important functions of miRNAs in drug resistance of CRC.

Silencing of lncRNA MIR497HG via CRISPR/Cas13d Induces Bladder Cancer Progression Through Promoting the Crosstalk Between Hippo/Yap and TGF-β/Smad Signaling

A subset of long non-coding RNAs (lncRNAs), categorized as miRNA-host gene lncRNAs (lnc-miRHGs), is processed to produce miRNAs and involved in cancer progression. This work aimed to investigate the influences and the molecular mechanisms of lnc-miRHGs MIR497HG in bladder cancer (BCa). The miR-497 and miR-195 were derived from MIR497HG. We identified that lnc-miRHG MIR497HG and two harbored miRNAs, miR-497 and miR-195, were downregulated in BCa by analyzing The Cancer Genome Atlas and our dataset. Silencing of MIR497HG by CRISPR/Cas13d in BCa cell line 5637 promoted cell growth, migration, and invasion in vitro. Conversely, overexpression of MIR497HG suppressed cell progression in BCa cell line T24. MiR-497/miR-195 mimics rescued significantly the oncogenic roles of knockdown of MIR497HG by CRISPR/Cas13d in BCa. Mechanistically, miR-497 and miR-195 co-ordinately suppressed multiple key components in Hippo/Yap and transforming growth factor β signaling and particularly attenuated the interaction between Yap and Smad3. In addition, E2F4 was proven to be critical for silencing MIR497HG transcription in BCa cells. In short, we propose for the first time to reveal the function and mechanisms of MIR497HG in BCa. Blocking the pathological process may be a potential strategy for the treatment of BCa.

Regulation of microRNA-497 expression in human cancer

MicroRNAs (miRNAs/miRs) are a type of non-coding single-stranded RNA, with a length of ~22 nt, which are encoded by endogenous genes and are involved in the post-transcriptional regulation of gene expression in animals and plants. Studies have demonstrated that miRNAs play an important role in the occurrence, development, metastasis, diagnosis and treatment of cancer. In recent years, miR-497 has been identified as one of the key miRNAs in a variety of cancer types and has been shown to be downregulated in a variety of solid tumors. However, the regulation of miR-497 expression involves a complex network, which is affected by several factors. The aim of the present review was to summarize the mechanism of regulation of miR-497 expression at the pre-transcriptional and transcriptional levels in cancer, as well as the role of miR-497 expression imbalance in cancer diagnosis, treatment and prognosis. The regulatory mechanisms of miR-497 expression may aid in our understanding of the causes of miR-497 expression imbalance and provide a reference value for further research on the diagnosis and treatment of cancer.

NF-κB maintains the stemness of colon cancer cells by downregulating miR-195-5p/497-5p and upregulating MCM2

BACKGROUND

Colon cancer represents one of the leading causes of gastrointestinal tumors in industrialized countries, and its incidence appears to be increasing at an alarming rate. Accumulating evidence has unveiled the contributory roles of cancer stem cells (CSCs) in tumorigenicity, recurrence, and metastases. The functions of NF-kappa B (NF-κB) activation on cancer cell survival, including colon cancer cells have encouraged us to study the role of NF-κB in the maintenance of CSCs in colon cancer.

METHODS

Tumor samples and matched normal samples were obtained from 35 colon cancer cases. CSCs were isolated from human colon cancer cell lines, where the stemness of the cells was evaluated by cell viability, colony-forming, spheroid-forming, invasion, migration, and apoptosis assays. NF-κB activation was then performed in subcutaneous tumor models of CSCs by injecting lipopolysaccharides (LPS) i.p.

RESULTS

We found that NF-κB activation could reduce the expression of miR-195-5p and miR-497-5p, where these two miRNAs were determined to be downregulated in colon cancer tissues, cultured colon CSCs, and LPS-injected subcutaneous tumor models. Elevation of miR-195-5p and miR-497-5p levels by their specific mimic could ablate the effects of NF-κB on the stemness of colon cancer cells in vivo and in vitro, suggesting that NF-κB could maintain the stemness of colon cancer cells by downregulating miR-195-5p/497-5p. MCM2 was validated as the target gene of miR-195-5p and miR-497-5p in cultured colon CSCs. Overexpression of MCM2 was shown to restore the stemness of colon cancer cells in the presence of miR-195-5p and miR-497-5p, suggesting that miR-195-5p and miR-497-5p could impair the stemness of colon cancer cells by targeting MCM2 in vivo and in vitro.

CONCLUSIONS

Our work demonstrates that the restoration of miR-195-5p and miR-497-5p may be a therapeutic strategy for colon cancer treatment in relation to NF-κB activation.

Regulation of MicroRNA-497-Targeting AKT2 Influences Tumor Growth and Chemoresistance to Cisplatin in Lung Cancer

Background

MicroRNA-497 (miR-497) has been implicated in several cancers. Increasing studies demonstrate the role of AKT2 in cancers as an oncogene which is closely associated with tumor aggressiveness by enhancing cancer cell survival, migration and invasion However, miR-497/AKT2 axis in non-small cell lung cancer (NSCLC) remains unclear.

Methods

Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of miR-497 and its target gene. The function of miR-497 in lung cancer was investigated through in vitro and in vivo assays (cell proliferation assay, cell migration assay, colony formation assay, flow cytometry assay, immunoblotting and tumorigenesis assay). Luciferase reporter assay was conducted to confirm the target gene of miR-497.

Results

In this study, we found that miR-497 was significantly downregulated in tumor tissues and blood samples of lung cancer patients. To understand the potential mechanism of miR-497 in inhibiting tumor growth, we showed that miR-497 blocked the activation of AKT2 and regulated cell proliferation, cell migration, colony formation and increases chemosensitivity of H1299 cells to cisplatin by inhibiting AKT2. MiR-497 also inhibited tumor growth and suppressed expression of AKT2 at the protein and mRNA levels in mouse xenograft tumors.

Conclusion

Taken together, our findings indicated that miR-497 suppresses the tumor growth by targeting AKT2, and the miR-497/AKT2 axis is a potential therapeutic target for NSCLC intervention.

Lipids and cancer: Emerging roles in pathogenesis, diagnosis and therapeutic intervention

With the advent of effective tools to study lipids, including mass spectrometry-based lipidomics, lipids are emerging as central players in cancer biology. Lipids function as essential building blocks for membranes, serve as fuel to drive energy-demanding processes and play a key role as signaling molecules and as regulators of numerous cellular functions. Not unexpectedly, cancer cells, as well as other cell types in the tumor microenvironment, exploit various ways to acquire lipids and extensively rewire their metabolism as part of a plastic and context-dependent metabolic reprogramming that is driven by both oncogenic and environmental cues. The resulting changes in the fate and composition of lipids help cancer cells to thrive in a changing microenvironment by supporting key oncogenic functions and cancer hallmarks, including cellular energetics, promoting feedforward oncogenic signaling, resisting oxidative and other stresses, regulating intercellular communication and immune responses. Supported by the close connection between altered lipid metabolism and the pathogenic process, specific lipid profiles are emerging as unique disease biomarkers, with diagnostic, prognostic and predictive potential. Multiple preclinical studies illustrate the translational promise of exploiting lipid metabolism in cancer, and critically, have shown context dependent actionable vulnerabilities that can be rationally targeted, particularly in combinatorial approaches. Moreover, lipids themselves can be used as membrane disrupting agents or as key components of nanocarriers of various therapeutics. With a number of preclinical compounds and strategies that are approaching clinical trials, we are at the doorstep of exploiting a hitherto underappreciated hallmark of cancer and promising target in the oncologist's strategy to combat cancer.

miRNA Clusters with Down-Regulated Expression in Human Colorectal Cancer and Their Regulation

Regulation of microRNA (miRNA) expression has been extensively studied with respect to colorectal cancer (CRC), since CRC is one of the leading causes of cancer mortality worldwide. Transcriptional control of miRNAs creating clusters can be, to some extent, estimated from cluster position on a chromosome. Levels of miRNAs are also controlled by miRNAs "sponging" by long non-coding RNAs (ncRNAs). Both types of miRNA regulation strongly influence their function. We focused on clusters of miRNAs found to be down-regulated in CRC, containing miR-1, let-7, miR-15, miR-16, miR-99, miR-100, miR-125, miR-133, miR-143, miR-145, miR-192, miR-194, miR-195, miR-206, miR-215, miR-302, miR-367 and miR-497 and analysed their genome position, regulation and functions. Only evidence provided with the use of CRC in vivo and/or in vitro models was taken into consideration. Comprehensive research revealed that down-regulated miRNA clusters in CRC are mostly located in a gene intron and, in a majority of cases, miRNA clusters possess cluster-specific transcriptional regulation. For all selected clusters, regulation mediated by long ncRNA was experimentally demonstrated in CRC, at least in one cluster member. Oncostatic functions were predominantly linked with the reviewed miRNAs, and their high expression was usually associated with better survival. These findings implicate the potential of down-regulated clusters in CRC to become promising multi-targets for therapeutic manipulation.

The Roles of Cancer Stem Cells and Therapy Resistance in Colorectal Carcinoma

Cancer stem cells (CSCs) are the main culprits involved in therapy resistance and disease recurrence in colorectal carcinoma (CRC). Results using cell culture, animal models and tissues from patients with CRC suggest the indispensable roles of colorectal CSCs in therapeutic failure. Conventional therapies target proliferating and mature cancer cells, while CSCs are mostly quiescent and poorly differentiated, thereby they can easily survive chemotherapeutic insults. The aberrant activation of Wnt/β-catenin, Notch, Hedgehog, Hippo/YAP (Yes-associated protein) and phosphatidylinositol 3-kinase/protein kinase B facilitates CSCs with excessive self-renewal and therapy resistance property in CRC. CSCs survive the chemo-radiotherapies by escaping therapy mediated DNA damage via altering the cell cycle checkpoints, increasing DNA damage repair capacity and by an efficient scavenging of reactive oxygen species. Furthermore, dysregulations of miRNAs e.g., miR-21, miR-93, miR-203, miR-215, miR-497 etc., modulate the therapeutic sensitivity of colorectal CSCs by regulating growth and survival signalling. In addition, a reversible quiescent G₀ state and the re-entering cell cycle capacity of colorectal CSCs can accelerate tumour regeneration after treatment. Moreover, switching to favourable metabolic signatures during a therapeutic regimen will add more complexity in therapeutic outcomes against CSCs. Therapeutic strategies targeting these underlying mechanisms of CSCs’ therapy resistance could provide a promising outcome, however, deep understanding and concerted research are necessary to design novel therapies targeting CSCs. To conclude, the understanding of these mechanisms of CSC in CRC could lead to the improved management of patients with CRC.

Long Noncoding RNA KIF9-AS1 Regulates Transforming Growth Factor-β and Autophagy Signaling to Enhance Renal Cell Carcinoma Chemoresistance via microRNA-497-5p

Renal cell carcinoma (RCC) has been regarded as one of the most malignant tumor types. Chemotherapy (such as sorafenib) is used as common strategy for treating RCC. To date, whether long noncoding RNA KIF9-AS1 is involved in RCC progression and drug resistance remains unknown. In this investigation, we detected gene expression levels by western blot and RT-qPCR. MTT and TUNEL experiments were used to show cell viability and apoptosis, respectively. KIF9-AS1 overexpression led to enhanced cell viability, increased IC₅₀ value of sorafenib, and decreased apoptosis. miR-497-5p acted as key interaction factor for KIF9-AS1 in RCC. More importantly, we found that transforming growth factor-β and autophagy signaling pathways were both critical effectors for mediating KIF9-AS1/miR-497-5p axis-induced drug resistance phenotypes (cell viability, IC₅₀, apoptosis) of RCC. In conclusion, our study revealed that KIF9-AS1 played a positive role in drug resistance of RCC cells to sorafenib, potentially driving the development of targeted diagnostic and therapeutical approaches.

Assessment of the Usefulness of the SEMA5A Concentration Profile Changes as a Molecular Marker in Endometrial Cancer

BACKGROUND

Semaphorin 5A (SEMA5A) functions not only in the nervous system but also in cancer transformation where its role has not yet been sufficiently studied and described.

OBJECTIVE

The aim of the study was to determine the changes in SEMA5A expression in endometrial cancer at various degrees of its differentiation (G1-G3) compared to control.

MATERIALS AND METHODS

The study group consisted of 45 patients with endometrial cancer at various grades: G1, 17; G2, 15; G3, 13. The control consisted of 15 women without neoplastic changes in the routine gynecological examination. The statistical analysis of immunohistochemical assessment of SEMA5A level was carried out using the Statistica 12 program based on the Kruskal-Wallis test and Dunn's post-hoc test (p<0.05).

RESULTS

The expression of SEMA5A (optical density) was observed in the control group (Me = 103.43) and in the study group (G1, Me = 140.72; G2, Me = 150.88; G3, Me = 173.77). Differences in expression between each grade and control and between individual grades turned out to be statistically significant (p<0.01). The protein level of SEMA5A expression increased with the decreasing degree of endometrial cancer differentiation.

CONCLUSION

In our research, we indicated the overexpression of SEMA5A protein in endometrial cancer. It is a valuable starting point for further consideration of the role of SEMA5A as a new supplementary molecular marker in endometrial cancer.

miR-200b-3p mitigates oxaliplatin resistance via targeting TUBB3 in colorectal cancer

BACKGROUND

Numerous abnormally expressed miRs have been reported involved in oxaliplatin (L-OHP) resistance of colorectal cancer (CRC). The present study aimed to investigate whether miR-200b-3p could regulate L-OHP resistance via targeting TUBB3 in CRC cells.

METHODS

L-OHP resistant HT29 and HCT116 cells were exposed to escalating concentrations of L-OHP up to 30 μm. The effect of miR-200b-3p on L-OHP resistant CRC cells was then evaluated using the cell counting kit-8 (CCK-8) assay. CRC cell apoptosis was detected using Annexin V-FITC/PI double staining. Bioinformatics algorithms and luciferase reporter assays were also performed to investigate whether TUBB3 was a direct target of miR-200b-3p.

RESULTS

miR-200b-3p declined in L-OHP resistant CRC tissues and cell lines, and the overexpression of miR-200b-3p elevated the L-OHP sensitivity in L-OHP resistant HT29 and HCT116 cells. In addition, we determined the potential mechanisms underlying miR-200b-3p-mediated reversal of L-OHP resistance by mediating its downstream target TUBB3, and the overexpression of miR-200b-3p could induce migration and growth inhibition and apoptosis in L-OHP resistant HT29 and HCT116 cells by silencing βIII-tubulin protein expression. However, the overexpression of TUBB3 reversed miR-200b-3p mimic-induced migration, as well as growth inhibition and apoptosis, in L-OHP resistant CRC cells.

CONCLUSIONS

miR-200b-3p improved L-OHP resistance and induced growth inhibition and cell apoptosis in L-OHP resistant CRC cells, and the underlying mechanism was mediated, at least partially, through the suppression of βIII-tubulin protein expression.

miR-497-5p mediates starvation-induced death in colon cancer cells by targeting acyl-CoA synthetase-5 and modulation of lipid metabolism

Modulation of fatty acids metabolism is an appropriate strategy for starvation-induced death in tumor cancers. Colon cancer cells express a high level of acyl-CoA synthetase-5 (ACSL5), and as yet no therapeutic approach has been achieved. Herein, ACSL5-related microRNAs (miRNAs) were identified via TargetScan, and their impacts on ACSL5 and lipid content along with metabolic activity, cell cycle, migration, and invasion of colorectal cancer (CRC) cells were examined, and subsequently compared with transcriptome for better visualization of intracellular-signaling networks. In vivo analysis was performed using BALB/c mice xenograft model of CRC injected with target miRNA. Clinical significances were also evaluated in 80 CRC tumors and matched adjacent normal tissues. There was a reverse correlation between ACSL5 and miR-497-5p, which miR-497-5p overexpression modulated CRC cell proliferation and development. A similar observation was received from the in vivo examination in which intratumoral injection of miR-497-5p reversed the tumor growth in the CRC xenograft model. Downregulation of miR-497-5p correlated with tumor differentiation, tumor, node, and metastasis staging, lymph node metastasis, and poor survival in patients with CRC. These results suggested that miR-497-5p upregulation could be considered as a therapeutic strategy for modulation of lipid metabolism in colon cancer.

Long Non-Coding RNA TTN-AS1 Promotes the Proliferation and Invasion of Colorectal Cancer Cells by Activating miR-497-Mediated PI3K/Akt/mTOR Signaling

Introduction

Long non-coding RNAs (lncRNAs) have obtained increasing attention due to their regulatory functions in many cancers. This work aimed to investigate the functional roles of lncRNA TTN-AS1 in colorectal cancer (CRC) and to explore the underlying mechanisms.

Methods

The expression profiles of TTN-AS1 and miR-497 in CRC tissues and cell lines were determined by RT-qPCR analysis. MTT assay, transwell assay, western blot analysis, and xenograft tumors in nude mice were employed to analyze the effects of TTN-AS1 on the proliferation, migration, invasion, EMT, and in vivo tumorigenesis of CRC cells. Bioinformatics analysis and dual-luciferase reporter assay determined the direct binding relation between TTN-AS1 and miR-497 in CRC.

Results

We observed a significant increase of TTN-AS1 expression level in CRC tissues and cell lines compared with normal counterparts. High expression of TTN-AS1 predicted a poor prognosis and was correlated with aggressive clinicopathological characteristics in CRC patients. Functionally, gain- and loss-of-function studies indicated that TTN-AS1 knockdown suppressed the proliferation, migration, invasion and epithelial–mesenchymal transition of CRC cells in vitro, whereas TTN-AS1 overexpression showed the complete opposite effects. Mechanistically, we found that TTN-AS1 could directly interact with miR-497, and co-transfection with miR-497 mimics blocked the activation of PI3K/Akt/mTOR signaling, and reversed the effects of TTN-AS1 overexpression in CRC cells.

Conclusion

To conclude, our findings provide novel insight into CRC tumorigenesis and indicate that TTN-AS1 may serve as a potential therapeutic target for CRC treatment.

Angioregulatory microRNAs in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer mortality. Angiogenesis is a rate-determining step in CRC development and metastasis. The balance of angiogenic and antiangiogenic factors is crucial in this process. Angiogenesis-related genes can be regulated post-transcriptionally by microRNAs (miRNAs) and some miRNAs have been shown to shuttle between tumor cells and the tumor microenvironment (TME). MiRNAs have context-dependent actions and can promote or suppress angiogenesis dependent on the type of cancer. On the one hand, miRNAs downregulate anti-angiogenic targets and lead to angiogenesis induction. Tumor suppressor miRNAs, on the other hand, enhance anti-angiogenic response by targeting pro-angiogenic factors. Understanding the interaction between these miRNAs and their target mRNAs will help to unravel molecular mechanisms involved in CRC progression. The aim of this article is to review the current literature on angioregulatory miRNAs in CRC.

Proteomic Analysis of miR-195 and miR-497 Replacement Reveals Potential Candidates that Increase Sensitivity to Oxaliplatin in MSI/P53wt Colorectal Cancer Cells

Most patients with advanced colorectal cancer (CRC) eventually develop resistance to systemic combination therapy. miR-195-5p and miR-497-5p are downregulated in CRC tissues and associated with drug resistance. Sensitization to 5-FU, oxaliplatin, and irinotecan by transfection with miR-195-5p and miR-497-5p mimics was studied using cell viability and clonogenic assays in cell lines HCT116, RKO, DLD-1, and SW480. In addition, proteomic analysis of transfected cells was implemented to identify potential targets. Significantly altered proteins were subjected to STRING (protein-protein interaction networks) database analysis to study the potential mechanisms of drug resistance. Cell viability analysis of transfected cells revealed increased sensitivity to oxaliplatin in microsatellite instable (MSI)/P53 wild-type HCT116 and RKO cells. HCT116 transfected cells formed significantly fewer colonies when treated with oxaliplatin. In sensitized cells, proteomic analysis showed 158 and 202 proteins with significantly altered expression after transfection with miR-195-5p and miR-497-5p mimics respectively, of which CHUK and LUZP1 proved to be coinciding downregulated proteins. Resistance mechanisms of these proteins may be associated with nuclear factor kappa-B signaling and G1 cell-cycle arrest. In conclusion, miR-195-5p and miR-497-5p replacement enhanced sensitivity to oxaliplatin in treatment naïve MSI/P53 wild-type CRC cells. Proteomic analysis revealed potential miRNA targets associated with the cell-cycle which possibly bare a relation with chemotherapy sensitivity.

Inflammatory Micro-environment Contributes to Stemness Properties and Metastatic Potential of HCC via the NF-κB/miR-497/SALL4 Axis

Increasing evidence has demonstrated the essential role of inflammatory micro-environment in tumorigenesis and tumor progression. Some cancer cells in tumor maintain typical stemness properties and, with the capacity of self-renewal, are thought to be crucial for the initiation and maintenance of tumors as well as their metastasis. Although both inflammatory micro-environment and stemness properties played crucial roles in tumor initiation and development, currently it is still unclear whether and how the inflammatory micro-environment promotes cancer stemness properties. Here, we show the first evidence that the inflammatory micro-environment promotes the stemness properties and metastatic potential of hepatocellular carcinoma (HCC) via the NF-κB/miR-497/SALL4 axis. We discover that miR-497 directly targets SALL4, negatively regulates its expression, and further inhibits the self-renewal and metastasis of HCC; more importantly, inflammatory factor TNF-α inhibits the expression of miR-497 via NF-kB-mediated negative transcriptional regulation and simultaneously upregulates the expression of SALL4 and promotes the self-renewal and metastasis phenotypes of HCC cells. Moreover, lower expression of miR-497 is significantly associated with poor prognosis in HCC patients. Taken together, our findings not only revealed a novel signaling pathway (NF-κB/miR-497/SALL4 axis) to connect inflammation with stemness properties, and clarified the molecular mechanisms underlying the inflammation-mediated self-renewal and metastasis phenotypes, but also provided novel molecular targets for developing new anticancer strategies.

miR-497-5p inhibits gastric cancer cell proliferation and growth through targeting PDK3

MicroRNA plays an important role in gastric cancer (GC) development, while the function of miR-497-5p in this disease remains unknown. In the present study, we demonstrated miR-497-5p as a tumor suppressive microRNA in GC. miR-497-5p was down-regulated in GC tissues and its expression was associated with the disease stage. Inhibition of miR-497-5p promoted GC cell proliferation and growth. By contrast, miR-497-5p ectopic expression suppressed the proliferation and growth of GC cells. In addition, miR-497-5p inhibited DNA synthesis and enhanced apoptosis in GC cells. The cell cycle progression was suppressed by miR-497-5p. Mechanistically, miR-497-5p directly targeted and suppressed the expression of pyruvate dehydrogenase kinase 3 (PDK3), which is highly expressed in GC tissues. Over-expression of PDK3 promoted the proliferation of GC cells. Our study revealed that miR-497-5p inhibited GC cell proliferation and growth via targeting PDK3.

MicroRNA-497-5p attenuates IL-1β-induced cartilage matrix degradation in chondrocytes via Wnt/β-catenin signal pathway

Osteoarthritis (OA) is a degenerative joint disease. Degradation of extracellular matrix (ECM) in chondrocytes is closely related to joint destruction in OA progression. MicroRNAs (miRNAs) have been reported to play important roles in progression of OA. However, the roles of miR-497-5p in OA process and its underlying mechanism remain not been well established. Chondrocytes were obtained from articular cartilage and stimulated with IL-1β. The expression of miR-497-5p and Wnt3a was detected by qRT-PCR. Western blot analysis was performed to measure the proteins of Wnt3a, collagen II, aggrecan matrix metalloproteinase (MMP) 13 and ADAMTS4. Cell apoptosis was detected by flow cytometry. The putative binding sites of miR-497-5p and Wnt3a were predicted by Targetscan and verified through luciferase report assay. We found that miR-497-5p expression was reduced and Wnt3a expression was enhanced in OA cartilage and IL-1β-stimulated chondrocytes. Moreover, Wnt3a was a direct target of miR-497-5p, and expression of miR-497-5p was negatively correlated with Wnt3a level in OA cartilage. Furthermore, overexpression of miR-497-5p prominently increased the expression of cartilage matrix molecules collagen II and aggrecan, and reduced the expression of matrix-degrading enzymes MMP13 and ADAMTS4 while overexpression of Wnt3a reversed these effects, whereas addition of DKK-1attenuated the Wnt3a-mediated functions in IL-1β-stimulated chondrocytes. In conclusion, miR-497-5p attenuated IL-1β-induced cartilage matrix degradation in chondrocytes via Wnt/β-catenin signal pathway, providing a potential therapeutic target for treatment of OA.

Hypoxia Promotes Vascular Smooth Muscle Cell Proliferation through microRNA-Mediated Suppression of Cyclin-Dependent Kinase Inhibitors

Regulation of vascular smooth muscle cell (VSMC) proliferation is essential to maintain vascular homeostasis. Hypoxia induces abnormal proliferation of VSMCs and causes vascular proliferative disorders, such as pulmonary hypertension and atherosclerosis. As several cyclin/cyclin-dependent kinase (CDK) complexes and CDK inhibitors (CKIs) control cell proliferation, in this study, we investigated CKIs involved in the hypoxia-induced proliferation process of human primary pulmonary artery smooth muscle cells to understand the underlying molecular mechanism. We demonstrated that p15, p16, and p21 are downregulated in pulmonary artery smooth muscle cells when exposed to hypoxia. In addition, we identified novel hypoxia-induced microRNAs (hypoxamiRs) including miR-497, miR-1268a, and miR-665 that are upregulated under hypoxia and post-transcriptionally regulate p15, p16, and p21 genes, respectively, by directly targeting their 3'UTRs. These miRNAs promoted the proliferation of VSMCs, and their inhibition decreased VSMC proliferation even in hypoxic conditions. Overall, this study revealed that miRNA-mediated regulatory mechanism of CKIs is essential for hypoxia-induced proliferation of VSMCs. These findings provide insights for a better understanding of the pathogenesis of vascular proliferative disorders.

lncRNA SNHG1 cooperated with miR-497/miR-195-5p to modify epithelial-mesenchymal transition underlying colorectal cancer exacerbation

Our study was intended to provide evidence for whether long noncoding RNA (lncRNA) SNHG1 would accelerate the epithelial-mesenchymal transition (EMT) course intrinsic in colorectal cancer (CRC) by sponging downstream miR-497-5p and miR-195-5p. We altogether collected 338 pairs of CRC and noncancerous tissues, and meanwhile purchased five CRC cell lines (i.e., SW480, HCT116, Lovo, CaCO-2, and HT29) and human embryo intestinal mucosal tissue-sourced cell line (i.e., CCC-HIE-2). The CRC cells as mentioned above were appraised regarding their potencies in proliferation, migration, and invasion, after being transfected with pcDNA3.1-SNHG1, si-SNHG1, miR-195-5p mimic/inhibitor, and miR-497-5p mimic/inhibitor. Eventually, we depended on reverse transcription-polymerase chain reaction to assess SNHG1, miR-497-5p, and miR-195-5p expressions, and the protein levels of EMT-specific molecules were determined on the strength of western blotting. It seemed that there was a high potential for highly expressed SNHG1 and lowly expressed miR-497/miR-195 to symbolize CRC patients' unfavorable prognosis (p < .05). Concurrently, CRC cells were detected with higher SNHG1 expression and lower miR-497/miR-195 expression than CCC-HIE-2 cells (p < .05). In addition, the EMT process of CRC cells was facilitated markedly against the contexts of overexpressed SNHG1 and underexpressed miR-497-5p/miR-195-5p. Intriguingly, the strength of miR-195-5p collaborating with miR-497-5p in affecting the activity of CRC cells seemed to overweigh that of miR-497/miR-195-5p alone. Besides, both miR-195-5p and miR-497-5p were subjected to in vivo and in vitro modification of SNHG1 (p < .05). Conclusively, application of lncRNA SNHG1 for treating CRC might be promising, given its dual modulation of miR-497 and miR-195 underlying CRC pathogenesis.

Identification and Functional Verification of MicroRNA-16 Family Targeting Intestinal Divalent Metal Transporter 1 (DMT1) in vitro and in vivo

Divalent metal transporter 1 (DMT1) is a key transporter of iron uptake and delivering in human and animals. However, post-transcriptional regulation of DMT1 is poorly understood. In this study, bioinformatic algorithms (TargetScan, PITA, miRanda, and miRDB) were applied to predict, screen, analyze, and obtain microRNA-16 family members (miR-16, miR-195, miR-497, and miR-15b) targeting DMT1, seed sequence and their binding sites within DMT1 3′ untranslated region (3′ UTR) region. As demonstrated by dual-luciferase reporter assays, luciferase activity of DMT1 3′ UTR reporter was impaired/enhanced when microRNA-16 family member over-expression plasmid/its inhibitor was transfected to HCT116 cells. Corroboratively, co-transfection of microRNA-16 family member over-expression plasmid and DMT1 3′ UTR mutant reporter repressed the luciferase activity in HCT116 cells. In addition, over-expression microRNA-16 family member augmented its expression and diminished DMT1 protein expression in HCT116 cells. Interestingly, tail vein injection of miR-16 assay revealed reduced plasma iron levels, higher miR-16 expression, and lower DMT1 protein expression in the duodenum of mice. Taken together, we provide evidence that microRNA-16 family (miR-16, miR-195, miR-497, and miR-15b) is confirmed to repress intestinal DMT1 expression in vitro and in vivo, which will give valuable insight into post-transcriptional regulation of DMT1.

Current Evidence on miRNAs as Potential Theranostic Markers for Detecting Chemoresistance in Colorectal Cancer: A Systematic Review and Meta-Analysis of Preclinical and Clinical Studies

BACKGROUND

Findings from observational clinical studies examining the relationship between biomarker expression and theranosis in colorectal cancer (CRC) have been conflicting.

OBJECTIVE

We conducted this systematic review and meta-analysis to summarise the existing evidence to demonstrate the involvement of microRNAs (miRNAs) in chemoresistance and sensitivity in CRC through drug genetic pathways.

METHODS

Using PRISMA guidelines, we systematically searched PubMed and Science Direct for relevant studies that took place between 2012 and 2017. A random-effects model of meta-analysis was applied to evaluate the pooled effect size of hazard ratios (HRs) across the included studies. Cochran's Q test and the I² statistic were used to detect heterogeneity. A funnel plot was used to assess potential publication bias.

RESULTS

Of the 4700 studies found, 39 studies comprising 2822 patients with CRC met the inclusion criteria. The included studies used one or a combination of 14 chemotherapy drugs, including 5-fluorouracil and oxaliplatin. Of the 60 miRNAs, 28 were associated with chemosensitivity, 20 with chemoresistance, and one with differential expression and radiosensitivity; ten miRNAs were not associated with any impact on chemotherapy. The results outline the importance of 34 drug-regulatory pathways of chemoresistance and sensitivity in CRC. The mean effect size was 0.689 (95% confidence interval 0.428-1.110), indicating that the expression of miRNAs decreased the likelihood of death by about 32%.

CONCLUSION

Studies have consistently shown that multiple miRNAs could act as clinical predictors of chemoresistance and sensitivity. An inclusion of supplementary miRNA estimation in CRC routine practice needs to be considered to evaluate the efficacy of chemotherapy after confirming our findings with large-scale prospective cohort studies.

PROSPERO REGISTRATION NUMBER

CRD42017082196.

Obesity, Insulin Resistance, and Colorectal Cancer: Could miRNA Dysregulation Play A Role?

Obesity is associated with insulin resistance and low-grade inflammation. Insulin resistance is a risk factor for cancer. A recent chapter in epigenetics is represented by microRNAs (miRNAs), which post-transcriptionally regulate gene expression. Dysregulated miRNA profiles have been associated with diseases including obesity and cancer. Herein we report dysregulated miRNAs in obesity both in animal models and in humans, and we also document dysregulated miRNAs in colorectal cancer (CRC), as example of an obesity-related cancer. Some of the described miRNAs are found to be similarly dysregulated both in obesity, insulin resistance (IR), and CRC. Thus, we present miRNAs as a potential molecular link between obesity and CRC onset and development, giving a new perspective on the role of miRNAs in obesity-associated cancers.

Downregulated microRNAs in the colorectal cancer: diagnostic and therapeutic perspectives

Colorectal cancer (CRC), the third most common cancer in the world, has no specific biomarkers that facilitate its diagnosis and subsequent treatment. The miRNAs, small single-stranded RNAs that repress the mRNA translation and trigger the mRNA degradation, show aberrant levels in the CRC, by which these molecules have been related with the initiation, progression, and drug-resistance of this cancer type. Numerous studies show the microRNAs influence the cellular mechanisms related to the cell cycle, differentiation, apoptosis, and migration of the cancer cells through the post-transcriptionally regulated gene expression. Specific patterns of the upregulated and down-regulated miRNA have been associated with the CRC diagnosis, prognosis, and therapeutic response. Concretely, the downregulated miRNAs represent attractive candidates, not only for the CRC diagnosis, but for the targeted therapies via the tumor-suppressing microRNA replacement. This review shows a general overview of the potential uses of the miRNAs in the CRC diagnosis, prognosis, and treatment with a special focus on the downregulated ones. [BMB Reports 2018; 51(11): 563-571].

lncRNA CASC9 positively regulates CHK1 to promote breast cancer cell proliferation and survival through sponging the miR‑195/497 cluster

Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) play important roles in the pathogenesis and development of diverse types of human disorders. Cancer susceptibility candidate 9 (CASC9), a gene encoding a lncRNA, has frequently been reported to be dysregulated and has been implicated in multiple types of human malignancies. However, the biological role of lncRNA CASC9 in breast cancer (BC) remains largely unknown. The present study aimed to investigate the role of lncRNA CASC9 in BC and to elucidate the potential molecular mechanisms involved. In the present study, lncRNA CASC9 was found to be significantly upregulated in both BC tissues and cell lines. Furthermore, functional analyses revealed that lncRNA CASC9 accelerated BC cell proliferation, promoted cell cycle progression and suppressed cell apoptosis. Moreover, mechanical experiments demonstrated that lncRNA CASC9 positively regulated checkpoint kinase 1 (CHK1) by competitively binding to the miR-195/497 cluster in BC cells. Additionally, the knockdown of lncRNA CASC9 was observed to suppress breast tumor growth in vivo. Taken together, the results of this study indicate that lncRNA CASC9 plays an oncogenic role in BC through sponging the miR-195/497 cluster, and that lncRNA CASC9 may be used as a novel therapeutic target and as a potential diagnostic marker for BC.