MicroRNA-497 suppresses renal cell carcinoma by targeting VEGFR-2 in ACHN cells

Semi-synthesized anticancer theobromine derivatives targeting VEGFR-2: in silico and in vitro evaluations

Vascular endothelial cell proliferation and angiogenesis are all crucially impacted by Endothelial Growth Factor Receptor-2 (VEGFR-2). Its expression is significantly boosted throughout pathologic angiogenesis causing the development of tumors. Sothat, inhibition of VEGFR-2 has crucial role in cancer treatment. In this study, novel semisynthetic theobromine derivatives were rationally designed as VEGFR-2 inhibitors and subjected to in vitro testing for their ability to block VEGFR-2 activation. Furthermore, the antiproliferative effects of these derivatives were evaluated. Compound 7 g exhibited the most potent anti-VEGFR-2 activity, with an IC50 value of 0.072 µM, and demonstrated excellent dose-dependent inhibitory activity against both MCF-7 and HepG2 cancer cells with IC50 values of 19.35 and 27.89 µM, respectively. Notably, compound 7 g exhibited high selectivity indices of 2.6 and 1.8 against MCF-7 and HepG2 cells, respectively. Compound 7 g induced G2/M phase cell cycle arrest, promoted apoptosis, and boosted immunomodulation by downregulating TNF-α expression and upregulating IL-2 levels in MCF-7 cells. The molecular docking analysis revealed that compound 7 g could bind effectively to the active site of VEGFR-2, and molecular dynamic simulations confirmed the stability of the VEGFR-2/compound 7 g complex. Furthermore, ADME and toxicity profiling indicated the potential suitability of these compounds as drug candidates. In summary, compound 7 g hold promise as a VEGFR-2 inhibitor.Communicated by Ramaswamy H. Sarma.

Design, synthesis, and antitumor screening of new thiazole, thiazolopyrimidine, and thiazolotriazine derivatives as potent inhibitors of VEGFR-2

New thiazole, thiazolopyrimidine, and thiazolotriazine derivatives 3-12 and 14a-f were synthesized. The newly synthesized analogs were tested for in vitro antitumor activity against HepG2, HCT-116, MCF-7, HeP-2, and Hela cancer cells. Results indicated that compound 5 displayed the highest potency toward the tested cancer cells. Compound 11b possessed enhanced effectiveness over MCF-7, HepG2, HCT-116, and Hela cancer cells. In addition, compounds 4 and 6 showed promising activity toward HCT-116, MCF-7, and Hela cancer cells and eminent activity against HepG2 and HeP-2 cells. Moreover, compounds 3-6 and 11b were tested for their capability to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) activity. The obtained results showed that compound 5 displayed significant inhibitory activity against VEGFR-2 (half-maximal inhibitory concentration [IC50 ] = 0.044 μM) comparable to sunitinib (IC50  = 0.100 μM). Also, the synthesized compounds 3-6 and 11b were subjected to in vitro cytotoxicity tests over WI38 and WISH normal cells. It was found that the five tested compounds displayed significantly lower cytotoxicity than doxorubicin toward normal cell lines. Cell cycle analysis proved that compound 5 induces cell cycle arrest in the S phase for HCT-116 and Hela cancer cell lines and in the G2/M phase for the MCF-7 cancer cell line. Moreover, compound 5 induced cancer cell death through apoptosis accompanied by a high ratio of BAX/BCL-2 in the screened cancer cells. Furthermore, docking results revealed that compound 5 showed the essential interaction bonds with VEGFR-2, which agreed with in vitro enzyme assay results. In silico studies showed that most of the analyzed compounds complied with the requirements of good oral bioavailability with minimal toxicity threats in humans.

Inhibition of VEGFR2 and EGFR signaling cooperatively suppresses the proliferation of oral squamous cell carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) is frequently overexpressed in oral squamous cell carcinoma (OSCC), and EGFR-targeting therapeutics have been widely employed to treat patients with a variety of carcinomas including OSCC. Here, we aimed to investigate alternative signaling for OSCC survival under the disruption of EGFR signaling.

METHODS

OSCC cell lines, namely HSC-3 and SAS, were utilized to investigate how EGFR disruption affects cell proliferation. Gene set enrichment analysis was performed to examine how EGFR disruption affects oncogenic signaling in OSCC cells. Disruption of KDR gene was performed using CRISPR/Cas9 techniques. A VEGFR inhibitor, vatalanib was used to research the impact of VEGFR inhibition on OSCC survival.

RESULTS

EGFR disruption significantly decreased the proliferation and oncogenic signaling including Myc and PI3K-Akt, in OSCC cells. Chemical library screening assays revealed that VEGFR inhibitors continued to inhibit the proliferation of EGFR-deficient OSCC cells. In addition, CRISPR-mediated disruption of KDR/VEGFR2 retarded OSCC cell proliferation. Furthermore, combined erlotinib-vatalanib treatment exhibited a more potent anti-proliferative effect on OSCC cells, compared to either monotherapy. The combined therapy effectively suppressed the phosphorylation levels of Akt but not p44/42.

CONCLUSION

VEGFR-mediated signaling would be an alternative signaling pathway for the survival of OSCC cells under the disruption of EGFR signaling. These results highlight the clinical application of VEGFR inhibitors in the development of multi-molecular-targeted therapeutics against OSCC.

Circulating and Endometrial Tissue microRNA Markers Associated with Endometrial Cancer Diagnosis, Prognosis, and Response to Treatment

In developed countries, endometrial cancer (EC) is one of the most common neoplasms of the female reproductive system. MicroRNAs (miRs) are a class of single-stranded noncoding RNA molecules with lengths of 19-25 nucleotides that bind to target messenger RNA (mRNA) to regulate post-transcriptional gene expression. Although there is a large amount of research focused on identifying miRs with a diagnostic, prognostic, or response to treatment capacity in EC, these studies differ in terms of experimental methodology, types of samples used, selection criteria, and results obtained. Hence, there is a large amount of heterogeneous information that makes it difficult to identify potential miR biomarkers. We aimed to summarize the current knowledge on miRs that have been shown to be the most suitable potential markers for EC. We searched PubMed and Google Scholar without date restrictions or filters. We described 138 miRs with potential diagnostic, prognostic, or treatment response potential in EC. Seven diagnostic panels showed higher sensitivity and specificity for the diagnosis of EC than individual miRs. We further identified miRs up- or downregulated depending on the FIGO stage, precursor lesions, and staging after surgery, which provides insight into which miRs are expressed chronologically depending on the disease stage and/or that are modulated depending on the tumor grade based on histopathological evaluation.

CRISPR-mediated knockout of VEGFR2/KDR inhibits cell growth in a squamous thyroid cancer cell line

Squamous and anaplastic thyroid cancers are the most aggressive and life‐threatening cancer types in humans, with the involvement of lymph nodes in 59% of cases and distant metastases in 26% of cases of all thyroid cancers. The median survival of squamous thyroid cancer patients is < 8 months and therefore is of high clinical concern. Here, we show that both VEGFC and VEGFR2/KDR are overexpressed in thyroid cancers, indicating that VEGF/VEGFR signaling plays a carcinogenic role in thyroid cancer development. Using CRISPR/Cas9, we established a KDR knockout (KO) SW579 squamous thyroid cancer cell line that exhibited dramatically decreased colony formation and invasion abilities (30% and 60% reduction, respectively) when compared to scrambled control cells. To validate the potential of KDR as a therapeutic target for thyroid cancers, we used the KDR RTK inhibitor sunitinib. Protein analysis and live/dead assay were performed to demonstrate that sunitinib significantly inhibited cell growth signal transduction and induced cell apoptosis of SW579 cells. These results suggest that selective targeting of KDR may have potential for development into novel anti‐cancer therapies to suppress VEGF/VEGFR‐mediated cancer development in patients with clinical advanced thyroid cancer.

Identification of novel allosteric binding sites and multi-targeted allosteric inhibitors of receptor and non-receptor tyrosine kinases using a computational approach

EGFR1, VEGFR2, Bcr-Abl and Src kinases are key drug targets in non-small cell lung cancer (NSCLC), bladder cancer, pancreatic cancer, CML, ALL, colorectal cancer, etc. The available drugs targeting these kinases have limited therapeutic efficacy due to novel mutations resulting in drug resistance and toxicity, as they target ATP binding site. Allosteric drugs have shown promising results in overcoming drug resistance, but the discovery of allosteric drugs is challenging. The allosteric binding pockets are difficult to predict, as they are generally associated with high energy conformations and regulate protein function in yet unknown mechanisms. In addition, the discovery of drugs using conventional methods takes long time and goes through several challenges, putting the lives of many cancer patients at risk. Therefore, the aim of the present work was to apply the most successful, drug repurposing approach in combination with computational methods to identify kinase inhibitors targeting novel allosteric sites on protein structure and assess their potential multi-kinase binding affinity. Multiple crystal structures belonging to EGFR1, VEGFR2, Bcr-Abl and Src tyrosine kinases were selected, including mutated, inhibitor bound and allosteric conformations to identify potential leads, close to physiological conditions. Interestingly the potential inhibitors identified were peptides. The drugs identified in this study could be used in therapy as a single multi-kinase inhibitor or in a combination of single kinase inhibitors after experimental validation. In addition, we have also identified new hot spots that are likely to be druggable allosteric sites for drug discovery of kinase-specific drugs in the future.Communicated by Ramaswamy H. Sarma.

Silencing of circular RNA PUM1 inhibits clear cell renal cell carcinoma progression through the miR-340-5p/FABP7 axis

Circular RNAs (circRNAs) monitor the development of clear cell renal cell carcinoma (ccRCC). However, the role of CircPUM1 in ccRCC malignancy is not studied. We estimated the mechanism of CircPUM1 in ccRCC progression in this study. CircPUM1 expression in ccRCC tissues and cells was detected. The expression of CircPUM1 was interfered in ccRCC cells, and its effects on the growth of ccRCC cells were studied. Nuclear/cytosol fractionation assay was performed for the location of CircPUM1, and the downstream miR, gene, and pathway involved in ccRCC progression were explored through gain- and loss-of-function experiments. CircPUM1 was highly expressed in ccRCC samples and cells. Inhibition of CircPUM1 prevented the growth ccRCC cells. CircPUM1 was localized in the cytoplasm and bound to miR-340-5p. Overexpression of miR-340-5p inhibited the growth of ccRCC cells. miR-340-5p targeted FABP7, and CircPUM1 induced FABP7 expression and the activation of MEK/ERK pathway through competitively binding to miR-340-5p. Overexpression of FABP7 attenuated the inhibitory effect of CircPUM1 silencing on the growth of ccRCC cells. Overall, CircPUM1 upregulates FABP7 expression by competitively binding to miR-340-5p, and then activates the MEK/ERK pathway, thus promoting ccRCC progression.

miR-497-5p Decreased Expression Associated with High-Risk Endometrial Cancer

The current guidelines for diagnosis, prognosis, and treatment of endometrial cancer (EC), based on clinicopathological factors, are insufficient for numerous reasons; therefore, we investigated the relevance of miRNA expression profiles for the discrimination of different EC subtypes. Among the miRNAs previously predicted to allow distinguishing of endometrioid ECs (EECs) according to different grades (G) and from serous subtypes (SECs), we verified the utility of miR-497-5p. In ECs, we observed downregulated miR-497-5p levels that were significantly decreased in SECs, clear cell carcinomas (CCCs), and carcinosarcomas (CaSas) compared to EECs, thereby distinguishing EEC from SEC and rare EC subtypes. Significantly reduced miR-497-5p expression was found in high-grade ECs (EEC G3, SEC, CaSa, and CCC) compared to low-grade carcinomas (EEC G1 and mucinous carcinoma) and ECs classified as being in advanced FIGO (International Federation of Gynecology and Obstetrics) stages, that is, with loco-regional and distant spread compared to cancers located only in the uterus. Based on immunohistochemical features, lower miR-497-5p levels were observed in hormone-receptor-negative, p53-positive, and highly Ki-67-expressing ECs. Using a machine learning method, we showed that consideration of miR-497-5p expression, in addition to the traditional clinical and histopathologic parameters, slightly improves the prediction accuracy of EC diagnosis. Our results demonstrate that changes in miR-497-5p expression influence endometrial tumorigenesis and its evaluation may contribute to more precise diagnoses.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Simple Summary

Tumor cell invasiveness and metastasis are key processes in cancer progression and are composed of many steps. All of them are regulated by multiple microRNAs that either promote or suppress tumor progression. Multiple studies demonstrated that microRNAs target the mRNAs of multiple genes involved in the regulation of cell motility, local invasion, and metastatic niche formation. Thus, microRNAs are promising biomarkers and therapeutic targets in oncology.

Abstract

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Regulators at Every Step—How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

miR-129-5p and miR-130a-3p Regulate VEGFR-2 Expression in Sensory and Motor Neurons during Development

The wide-ranging influence of vascular endothelial growth factor (VEGF) within the central (CNS) and peripheral nervous system (PNS), for example through effects on axonal growth or neuronal cell survival, is mainly mediated by VEGF receptor 2 (VEGFR-2). However, the regulation of VEGFR-2 expression during development is not yet well understood. As microRNAs are considered to be key players during neuronal maturation and regenerative processes, we identified the two microRNAs (miRNAs)-miR-129-5p and miR-130a-3p-that may have an impact on VEGFR-2 expression in young and mature sensory and lower motor neurons. The expression level of VEGFR-2 was analyzed by using in situ hybridization, RT-qPCR, Western blot, and immunohistochemistry in developing rats. microRNAs were validated within the spinal cord and dorsal root ganglia. To unveil the molecular impact of our candidate microRNAs, dissociated cell cultures of sensory and lower motor neurons were transfected with mimics and inhibitors. We depicted age-dependent VEGFR-2 expression in sensory and lower motor neurons. In detail, in lower motor neurons, VEGFR-2 expression was significantly reduced during maturation, in conjunction with an increased level of miR-129-5p. In sensory dorsal root ganglia, VEGFR-2 expression increased during maturation and was accompanied by an overexpression of miR-130a-3p. In a second step, the functional significance of these microRNAs with respect to VEGFR-2 expression was proven. Whereas miR-129-5p seems to decrease VEGFR-2 expression in a direct manner in the CNS, miR-130a-3p might indirectly control VEGFR-2 expression in the PNS. A detailed understanding of genetic VEGFR-2 expression control might promote new strategies for the treatment of severe neurological diseases like ischemia or peripheral nerve injury.

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.

Insights into the Regulation of Tumor Angiogenesis by Micro-RNAs

One of the hallmarks of cancer is angiogenesis, a series of events leading to the formation of the abnormal vascular network required for tumor growth, development, progression, and metastasis. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNAs whose functions include modulation of the expression of pro- and anti-angiogenic factors and regulation of the function of vascular endothelial cells. Vascular-associated microRNAs can be either pro- or anti-angiogenic. In cancer, miRNA expression levels are deregulated and typically vary during tumor progression. Experimental data indicate that the tumor phenotype can be modified by targeting miRNA expression. Based on these observations, miRNAs may be promising targets for the development of novel anti-angiogenic therapies. This review discusses the role of various miRNAs and their targets in tumor angiogenesis, describes the strategies and challenges of miRNA-based anti-angiogenic therapies and explores the potential use of miRNAs as biomarkers for anti-angiogenic therapy response.

VEGFR2 promotes tumorigenesis and metastasis in a pro-angiogenic-independent way in gastric cancer

Background

VEGF/VEGFR2 pathway is the central therapeutic target in anti-angiogenic treatment in multiple cancers. However, little work has been carried out concerning the pro-malignancy functions of VEGFR2 that are independent of its pro-angiogenesis effects in gastric cancer. Here, we demonstrated that VEGFR2 up-regulation in gastric cancer tissues was a prognostic marker for poor disease-free survival and overall survival of gastric cancer patients.

Methods

Immunohistochemistry was used to detect VEGFR2 and VTN expressions in specimens. Kaplan–Meier curves were constructed for survival analysis. Stably knockdown cell lines and overexpression cell lines were constructed by small interfering RNA and plasmids transfection. Real-time PCR and Western blot were used to confirm the expressions of target genes at both RNA and protein levels. Cell proliferation was measured by using Cell Counting Kit-8 and xenograft models. Microarray and bioinformatic analysis were also performed to identify the relationship between Vitronectin (VTN) and VEGFR2.

Results

When overexpressed in gastric cancer cells, VEGFR2 increased cellular proliferation and invasion in vitro and tumor formation in xenograft models. By using integrating microarray and bioinformatic analysis, we identifiedVTN as a downstream of VEGFR2 pathway. In gain- and loss-of function analysis in gastric cancer cells, VTN was further verified in consistent with VEGFR2 in expression levels and in regulating cell growth and motility in vitro and in vivo. Moreover, in gastric cancer samples, VTN was as also revealed as a poor prognostic factor.

Conclusions

Our present findings defined a novel activity for VEGFR2 in promoting tumorogenicity, motility and indicating a poor survival in gastric cancer beyond its known pro-angiogenic effects.

Implications

Our present findings defined a novel activity for VEGFR2 in promoting tumorogenicity, motility and indicating a poor survival in gastric cancer beyond its known pro-angiogenic effects, which may provide a new and valuable target for design of therapies for intervention and a new cognitive perspective for the anti-angiogenesis therapies.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5322-0) contains supplementary material, which is available to authorized users.

MicroRNA-497-5p inhibits proliferation and invasion of non-small cell lung cancer by regulating FGF2

Increasing number of microRNAs (miRNAs) have been reported to play an important role in the development and progression of non-small cell lung cancer (NSCLC). In particular, microRNA-497-5p (miR-497-5p) has been proposed as a tumor suppressor miRNA in human cancers. However, the role of miR-497-5p and its potential molecular mechanism associated with NSCLC are less studied. Therefore, the role of miR-497-5p in the pathogenesis of NSCLC was investigated. In the present study, the expression of miR-497-5p was significantly downregulated in NSCLC. Moreover, overexpression of miR-497-5p inhibited the proliferation and invasion of NSCLC cells by suppressing FGF2. In addition, FGF2 was a downstream target of miR-497-5p in NSCLC. FGF2 was upregulated in NSCLC promoting cell proliferation and invasion. Overexpression of FGF2 impaired the inhibitory effect of miR-497-5p in NSCLC. Taken together, these results demonstrate that miR-497-5p is a tumor suppressor miRNA and demonstrate its potential for future use in the treatment of human NSCLC.

FGFR1 is an independent prognostic factor and can be regulated by miR-497 in gastric cancer progression

Fibroblast growth factor receptor 1 (FGFR1) has been reported in gastric cancer to be a prognostic factor. However, miR-497-targeted FGFR1 has not been explored in the carcinogenesis of gastric cancer. The present study intended to revalidate the prognostic significance of FGFR1 in patients with gastric cancer, and the mechanism of miR-497-regulated FGFR1 was investigated in gastric cancer cell proliferation and apoptosis. The messenger RNA (mRNA) and protein levels were assayed by RT-qPCR and western blotting, respectively. The targeted genes were predicted by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay. Cell proliferation was analyzed by CCK-8 assay. Annexin V-FITC/PI staining was used to evaluate the apoptosis in AGS and SGC-7901 cells. FGFR1 was frequently up-regulated in gastric cancer tissues and associated with poor overall survival in patients with gastric cancer. Interestingly, FGFR1 loss-of-function resulted in a significant growth inhibition and apoptosis in AGS and SGC-7901 cells. In addition, we found that miR-497 was inhibited in gastric cancer tissues and cell lines, while overexpression of miR-497 could suppress proliferation and induce apoptosis in AGS and SGC-7901 cells. Importantly, bioinformatics analysis and experimental data suggested that FGFR1 was a direct target of miR-497, which could inhibit FGFR1 expression when transfected with miR-497 mimics. Furthermore, we found that overexpression of FGFR1 reversed the growth inhibition and apoptosis of miR-497 mimics in AGS and SGC-7901 cells. These findings suggested that overexpression of miR-497 inhibited proliferation and induced apoptosis in gastric cancer through the suppression of FGFR1.

LncRNA GACAT3 predicts poor prognosis and promotes cell proliferation in breast cancer through regulation of miR-497/CCND2

Breast cancer is the most common malignancy in women which increases gradually all over the world. LncRNA GACAT3 has been found to be increased in gastric cancer and associated with tumor malignancy. However, whether GACAT3 plays a role in the regulation of breast cancer is not known. In the present study, we found that GACAT3 expression was increased in breast cancer tissues and cells compared with adjacent normal tissues and normal cells. High GACAT3 expression was correlated with the poor prognosis of breast cancer patients. GACAT3 and cyclin D2 (CCND2) contained a binding site of miR-497. miR-497 was decreased in breast cancer tissues and cells compared with adjacent normal tissues and normal cells. Low miR-497 expression was correlated with the poor prognosis of breast cancer patients. In breast cancer tissues, the expression of miR-497 was negatively correlated with GACAT3. Downregulation of GACAT3 increased miR-497 expression. miR-497 mimic reduced the luciferase of GACAT3 and CCND2. Anti-miR-497 reversed the effects of GACAT3 downregulation. We also found that GACAT3 may act as a ceRNA for miR-497, enhancing the expression of CCND2. In conclusion, GACAT3 promotes breast cancer malignancy by sponging miR-497, leading to the enhancement of its endogenous target CCND2. These results suggest that GACAT3/miR-497/CCND2 is a potential therapeutic target and biomarker for breast cancer.

Prognostic Role of MicroRNA-497 In Cancer Patients: A Meta-analysis

Background: MicroRNA-497(miR-497) has been studied for its irreplaceable role of predicting the prognosis of various cancers, but there has been no systematic study to summarize the data. Consequently, we performed this meta-analysis to reveal the association between the expression level of miR-497 and cancer prognosis systematically.

Materials and Methods: PubMed was searched for appropriate studies and a total of 12 eligible publications with 989 cancer patients were recruited into our analysis to assess the strength of the association. Hazard ratios (HRs) and odds ratios (ORs) were analyzed to finish this work.

Results: The cancer patients who have high expressing level of miR-497 are less possible to have lymph node metastasis (OR = 0.25, 95% CI: 0.16-0.40, P < 0.001) and more likely to have favourable tumor-node-metastasis stage (OR = 0.29, 95% CI: 0.17-0.49, P < 0.001). Also, high miR-497 expression level was notably connected to better overall survival (pooled HR = 0.41, 95% CI: 0.32-0.53, P < 0.001).

Conclusions: High expressing levels of miR-497 might be a potential biomarker which can be used to predict the better prognosis of different cancer types.

Regulation of tumor angiogenesis by microRNAs: State of the art

MicroRNAs (miRNAs, miRs) are small (21-25 nucleotides) endogenous and noncoding RNAs involved in many cellular processes such as apoptosis, development, proliferation, and differentiation via binding to the 3'-untranslated region of the target mRNA and inhibiting its translation. Angiogenesis is a hallmark of cancer, which provides oxygen and nutrition for tumor growth while removing deposits and wastes from the tumor microenvironment. There are many angiogenesis stimulators, among which vascular endothelial growth factor (VEGF) is the most well known. VEGF has three tyrosine kinase receptors, which, following VEGF binding, initiate proliferation, invasion, migration, and angiogenesis of endothelial cells in the tumor environment. One of the tumor microenvironment conditions that induce angiogenesis through increasing VEGF and its receptors expression is hypoxia. Several miRNAs have been identified that affect different targets in the tumor angiogenesis pathway. Most of these miRNAs affect VEGF and its tyrosine kinase receptors expression downstream of the hypoxia-inducible Factor 1 (HIF-1). This review focuses on tumor angiogenesis regulation by miRNAs and the mechanism underlying this regulation.

Identification of miR-18a-5p as an oncogene and prognostic biomarker in RCC

BACKGROUND

RCC is a malignant tumor that originates from renal tubular epithelial cells, accounting for nearly 90% of renal malignancies and 3% of adult malignancies. It was reported that more than 30-40% of patients with early localized RCC still have recurrence and metastasis after receiving radical surgery. miRNAs are an endogenous non-coding small RNAs that play an important role in the regulation of tumor cell proliferation, differentiation and apoptosis.

METHODS

In our study, RT-qPCR, CCK-8 assay, wound scratch assay, transwell assay and flow cytometry assay were designed to identify the expression and functions of miR-18a-5p in RCC. Moreover, we collected the survival data from The Cancer Genome Atlas to predict and clarify the prognostic functions of miR-18a-5p in RCC. The correlation between miR-18a-5p expression and clinicopathological variables or overall survival was analyzed by 42 formalin-fixed paraffin-embedded (FFPE) renal cancer samples.

RESULTS

The expression of miR-18a-5p in RCC tissues and cell lines was elevated. Further researches suggested that upregulation of miR-18a-5p had a positive effect on RCC cell proliferation, migration, invasion and inhibition of apoptosis, while down-regulation of miR-18a-5p neutralized the effect. In addition, Data of TCGA and prognostic analysis of FFPE RCC samples revealed that high miR-18a-5p expression patients had significantly poorer survival.

CONCLUSIONS

These results demonstrated that miR-18a-5p functioned as an oncogene and prognostic biomarker in RCC.

MicroRNA-495 suppresses cell proliferation and invasion of hepatocellular carcinoma by directly targeting insulin-like growth factor receptor-1

Hepatocellular carcinoma (HCC) is the fifth most common malignancy and second-most frequent cause of cancer-associated deaths worldwide. Previously, increasing studies report that microRNAs (miRNAs/miRs) are abnormally expressed in various types of human cancers and may participate in the tumourigenesis and tumour development of HCC. miRNA-based targeted therapy is effective against different molecular targets and may increase the sensitisation of cancer cells to therapy by several folds. Therefore, further validation of potentially important miRNAs involved in HCC initiation and progression may provide valuable insights into the treatment of patients with HCC. miR-495 is abnormally expressed in multiple types of human cancers. However, the expression level and roles of miR-495 in HCC have yet to be completely elucidated. In the present study, miR-495 expression was frequently downregulated in HCC tissues and cell lines, and miR-495 expression levels were significantly correlated with tumour size, tumor-node-metastasis (TNM) stage and lymph node metastasis in patients with HCC. Functional assays revealed that miR-495 overexpression inhibited cell proliferation and invasion in HCC. Insulin-like growth factor receptor-1 (IGF1R) was identified as a direct target gene of miR-495 in HCC. IGF1R was upregulated in HCC tissues and negatively correlated with miR-495 expression level. The upregulation of IGF1R rescued the miR-495-induced tumour-suppressive roles in HCC cell proliferation and invasion, and the restored miR-495 expression inactivated the protein kinase B and extracellular regulated protein kinase signalling pathways in HCC. These results provide novel insights into the molecular mechanism underlying HCC progression, and suggest that miR-495 may be investigated as a novel therapeutic target for patients with this disease.

miR-493 inhibits proliferation and invasion in pancreatic cancer cells and inversely regulated hERG1 expression

The human ether-a-go-go-related potassium channel 1 (hERG1) is a component of the voltage-gated Kv11.1 potassium channel, which has been recently indicated to have a crucial role in the tumorigenesis of multiple tumors, including pancreatic carcinoma. Pancreatic carcinoma is one of the most malignant human cancer types, which has an extremely poor prognosis. The present study demonstrated that the expression levels of hERG1 were markedly elevated in pancreatic cancer tissues and pancreatic cancer cell lines, and that the abnormal hERG1 expression was significantly associated with the proliferation and invasion ability of pancreatic cancer. Furthermore, hERG1 was identified to be a direct target of miR-493, which is generally reduced in pancreatic cancer tissues and cell lines. These findings provide a novel insight into the regulatory mechanism of miR-493/hERG1 in pancreatic cancer cell proliferation and invasion, which may aid the development of novel diagnostic and therapeutic strategies for pancreatic cancer in the future.

Increased expression of Fibrinogen-Like Protein 2 is associated with poor prognosis in patients with clear cell renal cell carcinoma

Fibrinogen-like protein 2 (FGL2) is highly expressed in various tumour tissues and plays a vital role in tumour initiation and progression. This study evaluated the clinical significance of FGL2 in patients with clear cell renal cell carcinoma (ccRCC). FGL2 expression in fresh and 170 archived paraffin-embedded ccRCC tissues was measured by quantitative RT-PCR, western blotting, and immunohistochemitry. FGL2 expression was significantly upregulated in ccRCC. Statistical analyses by using Kaplan-Meier method showed that high FGL2 expression was associated with poor overall survival (OS) and recurrence-free survival (RFS) of patients with ccRCC. Multivariate analyses indicated that FGL2 was as an independent prognostic factor of survivaland that tumoural FGL2 levels could significantly predict the prognosis of patients with early-stage ccRCC. Nomogram systems, which integrated FGL2 expression and other clinical parameters, were established and were found to be better than TNM staging in predicting the OS and RFS of patients with ccRCC. FGL2 silencing led to a significant reduction in cells viability and increase in cells apoptosis, accompanied with a reduced ERK1/2 and p38 MAPK activation, in ccRCC cells. Thus, our results suggest that high FGL2 expression is a novel, independent, and an adverse prognostic factor of clinical outcomes in patients with ccRCC.