Overexpression of microRNA-497 suppresses cell proliferation and induces apoptosis through targeting paired box 2 in human ovarian cancer

MicroRNA-891a-5p is a novel biomarker for non-small cell lung cancer and targets HOXA5 to regulate tumor cell biological function

Numerous studies have shown that the dysregulation of microRNA (miRNA/miR) is an important factor in the pathogenesis of lung cancer. However, the role of miR-891a-5p in non-small cell lung cancer (NSCLC) remains unclear. Therefore, the present study aimed to examine the clinical value and biological function of miR-891a-5p in NSCLC. The mRNA expression level of miR-891a-5p in NSCLC was determined using reverse transcription-quantitative PCR and was used to determine the diagnostic value of miR-891a-5p, by creating a receiver operating characteristic curve. Kaplan-Meier and Cox regression analyses were used to evaluate its prognostic value in patients with NSCLC. Furthermore, cell experiments were performed to investigate the underlying mechanisms and functional role of miR-891a-5p in NSCLC progression. The results indicated that miR-891a-5p expression level was significantly higher in serum and tissues from patients with NSCLC and NSCLC cell lines. In addition, serum miR-891a-5p was found to have a diagnostic value in patients with NSCLC, and the increase in the expression level of miR-891a-5p in tumor tissues was associated with differentiation, and the tumor, node and metastases stages of cancer, which could be used for NSCLC prognosis. In addition, the experiments revealed that NSCLC cell proliferation, invasion and migration were significantly increased by the overexpression of miR-891a-5p and were significantly reduced by its downregulation. Furthermore, a luciferase reporter assay and the protein expression levels of HOXA5 showed that HOXA5 might be a miR-891a-5p target gene. In summary, the results indicated that high miR-891a-5p expression level could be a novel biomarker in patients with NSCLC and that it promoted tumor cell proliferation, invasion and migration. HOXA5 may be a target of miR-891a-5p, which may mediate miR-891a-5p function in NSCLC.

An Analysis of Mechanisms for Cellular Uptake of miRNAs to Enhance Drug Delivery and Efficacy in Cancer Chemoresistance

Up until recently, it was believed that pharmaceutical drugs and their metabolites enter into the cell to gain access to their targets via simple diffusion across the hydrophobic lipid cellular membrane, at a rate which is based on their lipophilicity. An increasing amount of evidence indicates that the phospholipid bilayer-mediated drug diffusion is in fact negligible, and that drugs pass through cell membranes via proteinaceous membrane transporters or carriers which are normally used for the transportation of nutrients and intermediate metabolites. Drugs can be targeted to specific cells and tissues which express the relevant transporters, leading to the design of safe and efficacious treatments. Furthermore, transporter expression levels can be manipulated, systematically and in a high-throughput manner, allowing for considerable progress in determining which transporters are used by specific drugs. The ever-expanding field of miRNA therapeutics is not without its challenges, with the most notable one being the safe and effective delivery of the miRNA mimic/antagonist safely to the target cell cytoplasm for attaining the desired clinical outcome, particularly in miRNA-based cancer therapeutics, due to the poor efficiency of neo-vascular systems revolting around the tumour site, brought about by tumour-induced angiogenesis. This acquisition of resistance to several types of anticancer drugs can be as a result of an upregulation of efflux transporters expression, which eject drugs from cells, hence lowering drug efficacy, resulting in multidrug resistance. In this article, the latest available data on human microRNAs has been reviewed, together with the most recently described mechanisms for miRNA uptake in cells, for future therapeutic enhancements against cancer chemoresistance.

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.

MiR-342-3p inhibits cell migration and invasion through suppressing forkhead box protein Q1 in ovarian carcinoma

Previous studies have shown that microRNAs are involved in the pathogenesis of ovarian carcinoma (OC). However, the abnormal expression and function of miR-342-3p have not been reported in OC. Therefore, this research was designed to explore its role in OC. In this study, qRT-PCR assay showed that the expression level of miR-342-3p was reduced in OC tissues and cell lines. Functionally, Transwell assay suggested that overexpression of miR-342-3p suppressed cell migration and invasion in OC. In addition, forkhead box protein Q1 (FOXQ1) was confirmed to be a direct target gene by luciferase activity assay. Furthermore, FOXQ1 was found to be upregulated and function as an oncogene in OC. More importantly, miR-342-3p was negatively correlated with FOXQ1 expression in OC tissues. Furthermore, overexpression of FOXQ1 could partially rescue inhibitory effect of miR-342-3p on cell migration and invasion in OC. In brief, we concluded that miR-342-3p inhibited migration and invasion of OC cells through suppressing FOXQ1 expression.

miR-744-5p Inhibits Non-Small Cell Lung Cancer Proliferation and Invasion by Directly Targeting PAX2

Non-small cell lung cancer is one of the leading causes of cancer-related death worldwide. MicroRNAs have been characterized as critical regulators for cancer progression including non-small cell lung cancer. This work explored microRNA-744-5p expression in non-small cell lung cancer cell lines and normal cell line using quantitative real-time polymerase chain reaction. Connection of microRNA-744-5p and paired box 2 was analyzed with bioinformatic analysis, luciferase activity reporter assay, and Western blot. Effects of microRNA-744-5p or paired box 2 expression on non-small cell lung cancer cell behaviors were analyzed using a series of in vitro experiments. MicroRNA-744-5p was found to have decreased expression in non-small cell lung cancer cell lines compared with normal cell line. Paired box 2 was identified as a direct target for microRNA-744-5p in non-small cell lung cancer. Overexpression of microRNA-744-5p inhibits non-small cell lung cancer cell proliferation, colony formation, and cell invasion in vitro through targeting paired box 2. The present study provided novel insights into the biological functions of microRNA-744-5p in non-small cell lung cancer.

Exosomal MiR-744 Inhibits Proliferation and Sorafenib Chemoresistance in Hepatocellular Carcinoma by Targeting PAX2

BACKGROUND Hepatocellular carcinoma (HCC) is a commonly occurring liver malignancy. Its prognosis remains unsatisfactory. Accumulating evidence has revealed that exosomal microRNAs (miRNAs) act as biomarkers and play crucial roles in the advancement of HCC. The current study explored the biological role and fundamental mechanism of exosomal miR-744 in HCC. MATERIAL AND METHODS The serum exosomes of HCC patients were isolated by differential ultracentrifugation. MiR-744 expression in HCC tissues, cell lines and serum exosomes were detected by quantitative real-time polymerase chain reaction (qRT-PCR). EdU (5-ethynyl-2'-deoxyuridine) assay and Cell Counting Kit-8 (CCK-8) assay were conducted to show the impacts of miR-744 or exosomal miR-744 on proliferation and sorafenib resistance in HepG2 cells. The target of miR-744 was ascertained by regulating the level of miR-744 in HepG2 cells. RESULTS MiR-744 is downregulated in HCC tissues and cell lines as well as in exosomes derived from patient serum and HepG2 cells. Additionally, downregulated miR-744 promotes HepG2 cell proliferation and inhibits the chemosensitivity of HepG2 cells to sorafenib. PAX2 was identified as the functional target of miR-744. Interestingly, miR-744 is decreased in exosomes derived from sorafenib-resistant HepG2 cells. Furthermore, when treated with the miR-744-enriched exosomes, the proliferation of HepG2 cells was significantly suppressed, and the sorafenib resistance was reduced. CONCLUSIONS MiR-744 has an imperative role in the propagation and chemoresistance of HCC. Serum exosomal miR-744 might act as a biomarker of HCC, and exosomal miR-744 might offer an innovative strategy for HCC treatment.

MicroRNA-497 inhibits multiple myeloma growth and increases susceptibility to bortezomib by targeting Bcl-2

Multiple myeloma (MM) is a common severe hematopoietic malignancy occuring in aged population. MicroRNA (miR)‑497 was previously reported to contribute to the apoptosis of other cell types, presumably through targeting B‑cell lymphoma 2 (Bcl‑2). In the present study, miRNA and protein expression levels were detected by reverse transcription‑quantitative polymerase chain reaction and western blot analyses, respectively. The cell proliferation and viability was measured using 3‑(4,5‑dimethylthiazol‑2‑yl)‑2, 5‑diphenyltetrazolium bromide and plate clonality assays, and the cell growth cycle was measured with a flow cytometer. Terminal deoxynucleotidyl transferase (TdT)‑mediated dUTP nick‑end‑labeling, Annexin V and caspase‑3 activity assays were performed to examine the cell apoptotic rates. The results showed that miR‑497 was markedly decreased, whereas Bcl‑2 was enhanced in MM tissues and cell lines. miR‑497 targeted Bcl‑2 and affected its downstream apoptosis‑related genes. The overexpression of miR‑497 promoted MM cell apoptosis through cell cycle arrest, and decreased colony genesis ability and viability. In addition, miR‑497 increased the sensitivity of MM cells to bortezomib. Taken together, miR‑497 suppressed MM cell proliferation and promoted apoptosis by directly targeting Bcl‑2 and altering the expression of downstream apoptosis‑related proteins. The combination of miR‑497 and bortezomib may enhance drug sensitivity, serving as a potentially available therapeutic method for MM.

Oncogenic and Tumor-Suppressive Roles of MicroRNAs with Special Reference to Apoptosis: Molecular Mechanisms and Therapeutic Potential

MicroRNAs (miRNAs) are the non-coding class of minute RNA molecules that negatively control post-transcriptional regulation of various functional genes. These miRNAs are transcribed from the loci present in the introns of functional or protein-coding genes, exons of non-coding genes, or even in the 3'-untranslated region (3'-UTR). They have potential to modulate the stability or translational efficiency of a variety of target RNA [messenger RNA (mRNA)]. The regulatory function of miRNAs has been elucidated in several pathological conditions, including neurological (Alzheimer's disease and Parkinson's disease) and cardiovascular conditions, along with cancer. Importantly, miRNA identification in cancer progression and invasion has evolved as an incipient era in cancer treatment. Several studies have shown the influence of miRNAs on various cancer processes, including apoptosis, invasion, metastasis and angiogenesis. In particular, apoptosis induction in tumor cells through miRNA has been extensively studied. The biphasic mode (up- and down-regulation) of miRNA expression in apoptosis and other cancer processes has already been determined. The findings of these studies could be utilized to develop potential therapeutic strategies for the management of various cancers. The present review critically describes the oncogenic and tumor suppressor role of miRNAs in apoptosis and other cancer processes, therapy resistance, and use of their presence in the body fluids as biomarkers.

miR-497 may enhance the sensitivity of non-small cell lung cancer cells to gefitinib through targeting the insulin-like growth factor-1 receptor

Background

Recently, studies have demonstrated that microRNA-497 (miR-497) plays an important role in modulating tumor cell sensitivity to chemotherapeutic drugs; however, its role in cellular resistance to the effects of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in treatment of non-small cell lung cancer (NSCLC) is not fully understood. In this study, we explored the potential of miR-497 in targeting the insulin-like growth factor-1 receptor (IGF-1R) signaling pathways to overcome gefitinib resistance.

Methods

A gefitinib resistant human lung adenocarcinoma A549 cell line (A549/GR) was established by the method of gefitinib mutagenesis culture. Next, the A549/GR cells were transfected with miR-497 mimics to establish an miR-497 overexpression model, designated A549/GR-miR497-mimic. MTT assay was used to assess cell resistance to gefitinib, and western blot assay was employed to evaluate alterations of IGF-1R and the AKT1 signaling pathway.

Results

We found that A549/GR-miR497-mimic cells (IC50 =33.76±0.97 µmol/L) were more sensitive to gefitinib than the control group (P<0.01). In addition, the expression levels of IGF-1R and phosphorylated AKT1 (p-AKT1) in A549/GR-miR497-mimic cells were reduced.

Conclusions

We demonstrated that miR-497 may have the effect of reversing gefitinib resistance and increasing the sensitivity of NSCLC cells to EGFR-TKIs by inhibiting the expression of IGF-1R and reducing activation of the downstream AKT signaling pathway. Thus, miR-497 plays a vital role in the acquired resistance to EGFR-TKIs, and it may represent a potential therapeutic strategy to treat NSCLC exhibiting resistance to EGFR-TKIs.

CP-31398 inhibits the progression of cervical cancer through reversing the epithelial mesenchymal transition via the downregulation of PAX2s

CP-31398, a styrylquinazoline, emerges from a screen for therapeutic agents that restore the wild-type DNA-binding conformation of mutant p53 to suppress tumors in vivo, but its effects on cervical cancer (CC) remain unknown. Hence, this study aimed to explore the effects CP-31398 has on the CC cells and to investigate whether it is associated with paired box 2 (PAX2) expression. CC cells were treated with different concentrations of CP-31398 (1, 2, 4, 6, 8, and 10 μg/ml) to determine the optimum concentration using fluorometric microculture cytotoxicity assay. After constructing the sh-PAX2 vector, CC cells were transfected with sh-PAX2 or treated with CP-31398. The effects of CP-31398 or PAX2 silencing on CC cell proliferation, apoptosis, invasion, and migration were evaluated. Epithelial mesenchymal transition (EMT)-related genes such as E-cadherin, vimentin, N-cadherin, snail, and twist in CC cells were detected. Tumor formation experiment in nude mice was performed to observe tumor growth. The optimum concentration of CP-31398 was 2 μg/ml. PAX2 was overexpressed in CC cells. CC cells treated with CP-31398 or treated with sh-PAX2 inhibited proliferation, invasion, and migration but promoted apoptosis with decreased PAX2 expression. The EMT process in CC cells was also reversed after treatment with CP-31398 or sh-PAX2. Moreover, the tumor formation experiment in nude mice revealed the inhibitory activity of CP-31398 in CC tumor in nude mice by suppressing PAX2. Our results provide evidence that CP-31398 could inhibit EMT and promote apoptosis of CC cells to curb CC tumor growth by downregulating PAX2.

Identification of micro-RNA expression profile related to recurrence in women with ESMO low-risk endometrial cancer

Background

Actual European pathological classification of early-stage endometrial cancer (EC) may show insufficient accuracy to precisely stratify recurrence risk, leading to potential over or under treatment. Micro-RNAs are post-transcriptional regulators involved in carcinogenic mechanisms, with some micro-RNA patterns of expression associated with EC characteristics and prognosis. We previously demonstrated that downregulation of micro-RNA-184 was associated with lymph node involvement in low-risk EC (LREC). The aim of this study was to evaluate whether micro-RNA signature in tumor tissues from LREC women can be correlated with the occurrence of recurrences.

Methods

MicroRNA expression was assessed by chip analysis and qRT-PCR in 7 formalin-fixed paraffin-embedded (FFPE) LREC primary tumors from women whose follow up showed recurrences (R+) and in 14 FFPE LREC primary tumors from women whose follow up did not show any recurrence (R−), matched for grade and age. Various statistical analyses, including enrichment analysis and a minimum p-value approach, were performed.

Results

The expression levels of micro-RNAs-184, -497-5p, and -196b-3p were significantly lower in R+ compared to R− women. Women with a micro-RNA-184 fold change < 0.083 were more likely to show recurrence (n = 6; 66%) compared to those with a micro-RNA-184 fold change > 0.083 (n = 1; 8%), p = 0.016. Women with a micro-RNA-196 fold change < 0.56 were more likely to show recurrence (n = 5; 100%) compared to those with a micro-RNA-196 fold change > 0.56 (n = 2; 13%), p = 0.001.

Conclusions

These findings confirm the great interest of micro-RNA-184 as a prognostic tool to improve the management of LREC women.

MicroRNAs in gynecological cancers: Small molecules with big implications

Gynecological cancers (GCs) are often diagnosed at advanced stages, limiting the efficacy of available therapeutic options. Thus, there remains an urgent and unmet need for innovative research for the efficient clinical management of GC patients. Research over past several years has revealed the enormous promise of miRNAs. These small non-coding RNAs can aid in the diagnosis, prognosis and therapy of all major GCs, viz., ovarian cancers, cervical cancers and endometrial cancers. Mechanistic details of the miRNAs-mediated regulation of multiple biological functions are under constant investigation, and a number of miRNAs are now believed to influence growth, proliferation, invasion, metastasis, chemoresistance and the relapse of different GCs. Modulation of tumor microenvironment by miRNAs can possibly explain some of their reported biological effects. miRNA signatures have been proposed as biomarkers for the early detection of GCs, even the various subtypes of individual GCs. miRNA signatures are also being pursued as predictors of response to therapies. This review catalogs the knowledge gained from collective studies, so as to assess the progress made so far. It is time to ponder over the knowledge gained, so that more meaningful pre-clinical and translational studies can be designed to better realize the potential that miRNAs have to offer.

Matrine suppresses the migration and invasion of NSCLC cells by inhibiting PAX2-induced epithelial-mesenchymal transition

Non-small cell lung cancer (NSCLC) is the major cause of deaths among all the cancer types worldwide. Most of the NSCLC is diagnosed at an advanced stage and the 5-year overall survival rate is low. The reason for the low survival rate of patients with NSCLC is mainly due to distant metastasis. Matrine, a traditional Chinese medicine, has been shown a significant anti-proliferation and anti-invasive effect in tumors. However, little is known on the anti-invasive mechanism of matrine in lung cancer. Therefore, we tried to investigate the molecular mechanism of matrine on the invasive ability of NSCLC cells in vitro. Cell Counting Kit-8 assay was used to evaluate the cell viability. Transwell assay was used to detect the migration and invasion abilities. Microarray assay was used to analyze the differentiated expression genes with or without matrine treatment. Western blotting and real-time polymerase chain reaction were applied to detect the expressions of PAX2, E-cadherin and N-cadherin. Our study showed that matrine could suppress the proliferative activity of NSCLC cells in a dose- and time-dependent manner. Further investigation discovered that the migration and invasion of NSCLC cells were significantly inhibited by treatment with different concentrations of matrine. Microarray assay, real-time polymerase chain reaction and western blotting showed that matrine could significantly decrease the expression of PAX2. In addition, epithelial-mesenchymal transition and related proteins were decreased. In conclusion, matrine may block PAX2 expression to interfere with epithelial-mesenchymal transition signaling pathway that ultimately inhibit the migration and invasion of NSCLC cells in vitro. Matrine might serve as a potential agent for NSCLC treatment.

miR-216b inhibits glioma cell migration and invasion through suppression of FoxM1

MicroRNAs (miRNAs) play a vital role in tumour biological and pathologic processes. In the present study, we aimed to detect the expression and biological role of miR-216b in glioma. Our data showed that miR-216b was significantly downregulated in human glioma tissues and cells. Ectopic expression of miR-216b inhibited the proliferation and invasion of U87 and U251 cells and suppressed the growth of xenograft tumours in vivo. Bioinformatic and luciferase reporter analyses identified Forkhead box protein M1 (FoxM1) as a direct target of miR-216b. Overexpression of miR-216b inhibited the expression of FoxM1 in glioma cells. Rescue experiments demonstrated that co-transfection of FoxM1 lacking the 3'-untranslated region partially prevented miR‑216b-induced inhibition of glioma cell growth and invasion. In vivo studies indicated that ectopic expression of miR-216b impeded the proliferation of glioma xenograft tumours in nude mice, coupled with a decreased in FoxM1 protein expression and the percentage of Ki-67-positive tumour cells. Taken together, our results provide evidence of the suppressive activity of miR‑216b in glioma, which is largely ascribed to downregulation of FoxM1. Restoration of miR-216b may provide a novel potential therapeutic agent for glioma.

MicroRNA‑497 inhibits cellular proliferation, migration and invasion of papillary thyroid cancer by directly targeting AKT3

Thyroid cancer is the most common tumor of the endocrine organs. Emerging studies have indicated the critical roles of microRNAs (miRs) in papillary thyroid cancer (PTC) formation and progression through function as tumor suppressors or oncogenes. The present study investigated the expression level and biological roles of miR-497 in PTC and its underlying mechanisms. It was demonstrated that the expression level of miR-497 was reduced in both PTC tissues and cell lines. Enforced expression of miR-497 suppressed PTC cell proliferation, migration and invasion. According to bioinformatics analysis, a luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blotting, RAC-γ serine/threonine-protein kinase (AKT3) was demonstrated to be the direct target gene of miR-497. In addition, AKT3 expression increased in PTC tissues and negatively correlated with miR-497 expression. Furthermore, downregulation of AKT3 also suppressed cell proliferation, migration and invasion of PTC, which had similar roles to miR-497 overexpression in PTC cells. Taken together, these results suggested that this newly identified miR-497/AKT3 signaling pathway may contribute to PTC occurrence and progression. These findings provide novel potential therapeutic targets for the therapy of PTC.