miR-137 inhibits proliferation of melanoma cells by targeting PAK2

Regulation of Cancer Metastasis by PAK2

PAK2 is a serine-threonine kinase and a member of the p21-activated kinase (PAK) family. PAK2 is activated by GTP-bound rho family GTPases, Rac, and Cdc42, and it regulates actin dynamics, cell adhesion to the extracellular matrix, and cell motility. In various types of cancers, PAK2 has been implicated in the regulation of cancer cell proliferation, cell cycle, and apoptosis. In addition, recent studies have shown that PAK2 plays an important role in cancer cell metastasis, indicating PAK2 as a potential therapeutic target. This review discusses recent discoveries on the functions of PAK2 in the regulation of various types of cancers. A better understanding of the mechanisms of function of PAK2 will facilitate future development of cancer therapies.

miR-137 regulates PTP61F, affecting insulin signaling, metabolic homeostasis, and starvation resistance in Drosophila

miR-137 is a highly conserved brain-enriched microRNA (miRNA) that has been associated with neuronal function and proliferation. Here, we show that Drosophila miR-137 null mutants display increased body weight with enhanced triglyceride content and decreased locomotor activity. In addition, when challenged by nutrient deprivation, miR-137 mutants exhibit reduced motivation to feed and prolonged survival. We show through genetic epistasis and rescue experiments that this starvation resistance is due to a disruption in insulin signaling. Our studies further show that miR-137 null mutants exhibit a drastic reduction in levels of the phosphorylated/activated insulin receptor, InR (InR-P). We investigated if this is due to the predicted miR-137 target, Protein Tyrosine Phosphatase 61F (PTP61F), ortholog of mammalian TC-PTP/PTP1B, which are known to dephosphorylate InR-P. Indeed, levels of an endogenously tagged GFP-PTP61F are significantly elevated in miR-137 null mutants, and we show that overexpression of PTP61F alone is sufficient to mimic many of the metabolic phenotypes of miR-137 mutants. Finally, we knocked-down elevated levels of PTP61F in the miR-137 null mutant background and show that this rescues levels of InR-P, restores normal body weight and triglyceride content, starvation sensitivity, as well as attenuates locomotor and starvation-induced feeding defects. Our study supports a model in which miR-137 is critical for dampening levels of PTP61F, thereby maintaining normal insulin signaling and energy homeostasis.

KIF20A Promotes CRC Progression and the Warburg Effect through the C-Myc/HIF-1α Axis

BACKGROUND

Colorectal cancer (CRC) is a prevalent form of cancer globally, characterized by a high mortality rate. Therefore, discovering effective therapeutic approaches for CRC treatment is critical.

METHODS

The levels of KIF20A in CRC clinical samples were determined using Western Blot and immunofluorescence assay. SW480 cells were transfected with siRNA targeting KIF20A, while HT-29 cells were transfected with a KIF20A overexpression vector. Cell viability and apoptosis of CRC cells were assessed using CCK-8 and TUNEL analysis. Migration ability was investigated using Transwell. The levels of pyruvate, lactate and ATP were determined through corresponding assay kits. Western Blot was applied to confirm the level of proteins associated with glycolysis, c- Myc, HIF-1α, PKM2 and LDHA. Subsequently, functional rescue experiments were conducted to investigate further the regulatory relationship between KIF20A, c-Myc, and HIF-1α in colorectal cancer (CRC), employing the c-Myc inhibitor 10058-F4 and c-Myc overexpression plasmids.

RESULTS

KIF20A was up-regulated in vivo and in vitro in CRC. KIF20A knockdown inhibited cell viability and migration while promoting cell apoptosis in SW480 cells. Conversely, overexpression of KIF20A yielded contrasting effects in HT-29 cells. Moreover, inhibition of KIF20A restrained the pyruvate, lactate production and ATP level, whereas overexpression of KIF20A enhanced the Warburg effect. Western Blot indicated that knockdown KIF20A attenuated the levels of c-Myc, HIF-1α, PKM2 and LDHA. In addition, rescue experiments further verified that KIF20A enhanced the Warburg effect by the KIF20A/c-Myc/HIF-1α axis in CRC.

CONCLUSION

KIF20A, being a crucial regulator in the progression of CRC, has the potential to be a promising therapeutic target for the treatment of CRC.

The P21-Activated Kinase 1 and 2 As Potential Therapeutic Targets for the Management of Cardiovascular Disease

Group I p21-activated kinases (Paks) are members of the serine/threonine protein kinase family. Paks are encoded by three genes (Pak 1 - 3) and are involved in the regulation of various biological processes. Pak1 and Pak2 are key members, sharing 91% sequence identity in their kinase domains. Recent studies have shown that Pak1/2 protect the heart from various types of stresses. Activated Pak1/2 participate in the maintenance of cellular homeostasis and metabolism, thus enhancing the adaptation and resilience of cardiomyocytes to stress. The structure, activation and function of Pak1/2 as well as their protective roles against the occurrence of cardiovascular disease are described in this review. The values of Pak1/2 as therapeutic targets are also discussed.

A Novel and Validated 8-Pyroptosis-Related Genes Based Risk Prediction Model for Diffuse Large B Cell Lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL), the most common type of Non-Hodgkin's Lymphoma (NHL), has a lethal nature. Thus, the establishment of a novel model to predict the prognosis of DLBCL and guide its therapy is an urgency. Meanwhile, pyroptosis is engaged in the progression of DLBCL with further investigations required to reveal the underlying mechanism.

METHODS

LASSO regression was conducted to establish a risk model based on those PRGs. External datasets, RT-qPCR and IHC images from The Human Protein Alta (HPA) database were utilized to validate the model. ssGSEA was utilized to estimate the score of immune components in DLBCL.

RESULTS

A model based on 8 PRGs was established to generate a risk score. Validation of the model confirmed its robust performance. The risk score was associated with advanced clinical stages and shorter overall survivals. Two novel second-line chemotherapies were found to be potential treatments for high-risk patients. The risk score was also found to be correlated with immune components in DLBCL.

CONCLUSION

This novel model can be utilized in clinical practices to predict the prognosis of DLBCL and guide the treatment of patients at high risk, providing an overview of immune regulatory program via pyroptosis in DLBCL.

LncRNA LNCOC1 is Upregulated in Melanoma and Serves as a Potential Regulatory Target of miR-124 to Suppress Cancer Cell Invasion and Migration

Background

A cascade of genes and pathways have been reported in the precise regulation of malignant melanoma (MM). Previous study has demonstrated that lncRNA LNCOC1 is an oncogenic factor in the pathogenesis and development of various cancers. The present study explored the functionalities of LNCOC1 and its interactions with miR-124 in MM.

Methods

A total of 65 melanoma patients were enrolled in this study. The expression of LNCOC1 and miR-124 after cell transfection were detected by RT-qPCR. The migration rates of SK-MEL-3 and A375 cells after transient transfection with LNCOC1 expression vector and miR-124 mimic was detected by trans-well assay.

Results

LNCOC1 was accumulated to high levels in melanoma, and it was significantly correlated with the low survival rate of melanoma patients. Our bioinformatics data showed that miR-124 could target LNCOC1. Overexpression of miR-124 could downregulate LNCOC1. However, up-regulated the expression of LNCOC1 did not affect the expression of miR-124. Our correlation analysis also revealed that the expression of LNCOC1 and miR-124 were inversely correlated in both melanoma tissues and non-tumor tissues. The trans-well invasion and migration assays indicated that overexpression of miR-124 inhibited the melanoma cell invasion and migration. However, overexpression of LNCOC1 promoted melanoma cell invasion and migration.

Conclusion

LNCOC1 is upregulated in melanoma, which can be considered as a potential target of miR-124 in modulating melanoma cell invasion and migration. LNCOC1 may also be an interfering target of MM therapy.

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

The Use of Nanomedicine to Target Signaling by the PAK Kinases for Disease Treatment

P21-activated kinases (PAKs) are serine/threonine kinases involved in the regulation of cell survival, proliferation, inhibition of apoptosis, and the regulation of cell morphology. Some members of the PAK family are highly expressed in several types of cancer, and they have also been implicated in several other medical disorders. They are thus considered to be good targets for treatment of cancer and other diseases. Although there are several inhibitors of the PAKs, the utility of some of these inhibitors is reduced for several reasons, including limited metabolic stability. One way to overcome this problem is the use of nanoparticles, which have the potential to increase drug delivery. The overall goals of this review are to describe the roles for PAK kinases in cell signaling and disease, and to describe how the use of nanomedicine is a promising new method for administering PAK inhibitors for the purpose of disease treatment and research. We discuss some of the basic mechanisms behind nanomedicine technology, and we then describe how these techniques are being used to package and deliver PAK inhibitors.

MicroRNA Signature in Melanoma: Biomarkers and Therapeutic Targets

Melanoma is the utmost fatal kind of skin neoplasms. Molecular changes occurring during the pathogenic processes of initiation and progression of melanoma are diverse and include activating mutations in BRAF and NRAS genes, hyper-activation of PI3K/AKT pathway, inactivation of p53 and alterations in CDK4/CDKN2A axis. Moreover, several miRNAs have been identified to be implicated in the biology of melanoma through modulation of expression of genes being involved in these pathways. In the current review, we provide a summary of the bulk of information about the role of miRNAs in the pathobiology of melanoma, their possible application as biomarkers and their emerging role as therapeutic targets for this kind of skin cancer.

Identification of shell-color-related microRNAs in the Manila clam Ruditapes philippinarum using high-throughput sequencing of small RNA transcriptomes

Shell-color polymorphism is a common phenomenon in several mollusk species and has been associated with thermal capacity, developmental stability, shell strength, and immunity. Shell-color polymorphism has been related to the differential expression of genes in several signal transduction pathways; however, the functions of micro-RNAs (miRNAs) in shell-color formation remain unclear. In the present study, we compared high-quality, small-RNA transcriptomes in three strains of the Manila clam Ruditapes philippinarum with specific shell-color patterns, artificially selected for six generations. Totals of 114 known and 208 novel miRNAs were identified by high-throughput sequencing, of which nine known and one novel miRNA were verified by stem-loop quantitative real time-polymerase chain reaction. Predicted miRNA targets were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. miR-137 and miR-216b and the Hedgehog signaling pathway and Wnt signaling pathway were identified as being potentially involved in pigment formation and regulation in R. philippinarum. These results may help to clarify the role of miRNAs in shell coloration and shed light on the mechanisms regulating color formation in bivalve shells.

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.

Immune Microenvironment Related Competitive Endogenous RNA Network as Powerful Predictors for Melanoma Prognosis Based on WGCNA Analysis

Cutaneous melanoma is the most life-threatening skin malignant tumor due to its increasing metastasis and mortality rate. The abnormal competitive endogenous RNA network promotes the development of tumors and becomes biomarkers for the prognosis of various tumors. At the same time, the tumor immune microenvironment (TIME) is of great significance for tumor outcome and prognosis. From the perspective of TIME and ceRNA network, this study aims to explain the prognostic factors of cutaneous melanoma systematically and find novel and powerful biomarkers for target therapies. We obtained the transcriptome data of cutaneous melanoma from The Cancer Genome Atlas (TCGA) database, 3 survival-related mRNAs co-expression modules and 2 survival-related lncRNAs co-expression modules were identified through weighted gene co-expression network analysis (WCGNA), and 144 prognostic miRNAs were screened out by univariate Cox proportional hazard regression. Cox regression model and Kaplan-Meier survival analysis were employed to identify 4 hub prognostic mRNAs, and the prognostic ceRNA network consisting of 7 lncRNAs, 1 miRNA and 4 mRNAs was established. After analyzing the composition and proportion of total immune cells in cutaneous melanoma microenvironment through CIBERSORT algorithm, it is found through correlation analysis that lncRNA-TUG1 in the ceRNA network was closely related to the TIME. In this study, we first established cutaneous melanoma’s TIME-related ceRNA network by WGCNA. Cutaneous melanoma prognostic markers have been identified from multiple levels, which has important guiding significance for clinical diagnosis, treatment, and further scientific research on cutaneous melanoma.

CCHE1 accelerated the initiation of oral squamous cell carcinoma through enhancing PAK2 expression by sponging miR-922

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a normal form of mouth cancer, comprising the majority of oral cancers. A large number of long non-coding RNAs (lncRNAs) have been reported due to their oncogenic function in cancers. Recent studies show that lncRNA CCHE1 is an oncogene in a wide range of cancers. Whether CCHE1 accelerates the progression of OSCC is still undiscovered.

METHODS

The qRT-PCR analysis was used to determine CCHE1, miR-922, and PAK2 expression levels. CCK8 and colony formation assays were applied to evaluate OSCC cell proliferative ability. Transwell assay was performed to investigate the capability of cell migration and invasion. Cell apoptosis was assessed by flow cytometry analysis. The distribution of CCHE1 in OSCC cells was confirmed via subcellular fractionation assay. Luciferase reporter assay was used to verify the connection between miR-922 and CCHE1 or PAK2.

RESULTS

qRT-PCR analysis identified the upregulation of CCHE1 in OSCC cells. Knockdown of CCHE1 curbed the proliferation, migration, and invasion and hastened the apoptosis in OSCC cell lines. Moreover, it was found that miR-922 could interact with CCHE1. Besides, PAK2 was identified as the target gene of miR-922 and its expression was negatively modulated by miR-922 and positively regulated by CCHE1. Restoration assay manifested that the suppressing influence of CCHE1 depletion on OSCC progression was rescued by amplified PAK2.

CONCLUSIONS

CCHE1 increases the expression of PAK2 to promote the progression of OSCC by competitively binding to miR-922 in OSCC cells.

MicroRNA-7-5p induces cell growth inhibition, cell cycle arrest and apoptosis by targeting PAK2 in non-small cell lung cancer

MicroRNAs (miR) are known to be critical regulators in tumor progression. miR-7-5p was reported to be involved in several cancers, including glioblastoma, cervical cancer, and melanoma, but its prognostic value and biological function in non-small-cell lung cancer (NSCLC) remain unclear. In this study, using quantitative real-time PCR analysis, we found that miR-7-5p was significantly downregulated in NSCLC tissues and cell lines. Lower miR-7-5p expression was associated with tumor-node-metastasis stage and tumor size by chi-squared test. Deceased miR-7-5p expression was associated with a worse prognosis in patients with NSCLC using Kaplan-Meier survival analysis and multivariate Cox regression analysis. Experiments in NSCLC cell lines (A549 and H1299) demonstrated that upregulation of miR-7-5p significantly suppressed cell proliferation, but induced cell cycle G0/G1 phase arrest and apoptosis using Cell Counting Kit-8, colony formation, and flow cytometry analysis. Through loss-of-function assays, we further demonstrated that downregulation of miR-7-5p promoted cell proliferation and cell cycle G1/S transition, but decreased cell apoptosis in SPC-A1 cells. Furthermore, P21-activated kinase 2 (PAK2) was predicted and confirmed as a direct target gene of miR-7-5p in NSCLC cells by luciferase reporter assay. In addition, we found PAK2 overexpression could partially reverse the effects of miR-7-5p on cell proliferation, cell cycle distribution, and apoptosis. We thus concluded that lower expression of miR-7-5p was associated with poor prognosis and NSCLC progression by directly targeting PAK2.

MiR-137 inhibits cell proliferation in acute lymphoblastic leukemia by targeting JARID1B

AIM

This study aimed to investigate the possible functions of interaction between JARID1B and miR-137 in ALL.

METHODS

The levels of H3K4me3 and H3K4me2 and the expression of JARID1B and miR-137 were analyzed in six ALL cell lines and 30 ALL patients. The effects of miR-137 and JARID1B on cell proliferation and apoptosis were investigated by silencing or promoting the respective genes. The interaction between miR-137 and JARID1B was confirmed by double-luciferase report assay.

RESULTS

The histone H3K4 expressions and miR-137 expression were lower in 30 ALL patients and in six ALL cell lines, while the expression of JARID1B was elevated. A negative correlation was observed between JARID1B and miR-137. Over-expression of miR-137 led to decreasing cell proliferation and increasing apoptosis in MOLT-4 and BALL-1 cells. MiR-137 inhibitor up-regulated JARID1B in these two cell lines, while promoted proliferation in BALL-1 cells only. Dual-luciferase report assay suggested that JARID1B was a direct target of miR-137 in ALL cell lines.

CONCLUSIONS

The expression of miR-137 was declined in ALL, and JARID1B was directly repressed by miR-137. Aberrant JARID1B expression could result in abnormal histone methylation, which might be one cause of ALL.

C-Phycocyanin Suppresses the In Vitro Proliferation and Migration of Non-Small-Cell Lung Cancer Cells through Reduction of RIPK1/NF-κB Activity

Phycocyanin, derived from Spirulina platensis, is a type of natural antineoplastic marine protein. It is known that phycocyanin exerts anticancer effects on non-small-cell lung cancer (NSCLC) cells, but its underlying mechanism has not been elucidated. Herein, the antitumor function and regulatory mechanism of phycocyanin were investigated in three NSCLC cell lines for the first time: H358, H1650, and LTEP-a2. Cell phenotype experiments suggested that phycocyanin could suppress the survival rate, proliferation, colony formation, and migration abilities, as well as induce apoptosis of NSCLC cells. Subsequently, transcriptome analysis revealed that receptor-interacting serine/threonine-protein kinase 1 (RIPK1) was significantly down-regulated by phycocyanin in the LTEP-a2 cell, which was further validated by qRT-PCR and Western blot analysis in two other cell lines. Interestingly, similar to phycocyanin-treated assays, siRNA knockdown of RIPK1 expression also resulted in growth and migration inhibition of NSCLC cells. Moreover, the activity of NF-κB signaling was also suppressed after silencing RIPK1 expression, indicating that phycocyanin exerted anti-proliferative and anti-migratory function through down-regulating RIPK1/NF-κB activity in NSCLC cells. This study proposes a mechanism of action for phycocyanin involving both NSCLC apoptosis and down regulation of NSCLC genes.

Phycocyanin Exerts Anti-Proliferative Effects through Down-Regulating TIRAP/NF-κB Activity in Human Non-Small Cell Lung Cancer Cells

Phycocyanin is a type of marine functional food additive, exerting a health care efficacy with no side effects. It has been shown that phycocyanin possesses anticancer function in non-small cell lung cancer (NSCLC) cells, but the underlying regulatory mechanism still remains unclear. Further investigation on the antineoplastic mechanism of phycocyanin would provide useful information on NSCLC treatment. In this study, we explored the in vitro function and mechanism of phycocyanin in three typical NSCLC cell lines, H1975, H1650, and LTEP-a2, for the first time. Phenotypic experiments showed that phycocyanin significantly induced the apoptosis as well as suppressed the growth of NSCLC cells. Transcriptome analysis suggested that toll/interleukin 1 receptor domain-containing adaptor protein (TIRAP) was significantly down-regulated by phycocyanin. Strikingly, similar to phycocyanin-treated assays, siRNA knockdown of TIRAP expression also resulted in the anti-proliferative phenomenon in NSCLC cells. In addition, the activity of NF-κB signaling was also suppressed after silencing TIRAP expression, revealing that phycocyanin exerted anti-proliferative function through down-regulating TIRAP/NF-κB activity in NSCLC cells. Collectively, this study has laid a theoretical basis on the treatment of NSCLC and the potential utilization of marine functional products.

P21 activated kinase 2 promotes pancreatic cancer growth and metastasis

Pancreatic cancer has an overall 5-year survival rate of only 9%, due to its rapid metastasis and poor prognosis. To combat this disease, novel therapeutic targets and biomarkers are required. In this study, immunohistochemistry was used to detect the expression of P21 activated kinase 2 (PAK2) protein in the tissues of cancer and the paired adjacent normal tissues. The association between PAK2 and the clinicopathologic features of patients with pancreatic cancer was subsequently analyzed. The results indicated that PAK2 was overexpressed in the cancer tissues, which indicated high pTNM stage, poor tumor grade, lymph node metastasis and vascular invasion. In addition, the results demonstrated evidence of a close association between PAK2 expression and poor prognosis of patients with pancreatic cancer. The results also suggested that PAK2 may promote pancreatic cancer cell proliferation and migration in vitro through clone formation, MTT, wound healing and Transwell assays. The present study further identified that PAK2 could stimulate pancreatic cancer growth and metastasis in mice. Decreased expression of proliferation marker protein Ki-67 and proliferating cell nuclear antigen in response to PAK2 knockdown further verified the role of PAK2 in promoting cell proliferation by western blot analysis. In addition, the expression levels of matrix metallopeptidase (MMP) 2 and MMP9 were decreased in PANC1 and BxPC3 cell lines transfected with PAK2-short hairpin RNA as indicated in western blot analysis, suggesting a function of PAK2 in promoting cell invasion. Collectively, these findings revealed a critical role for PAK2 in the development of pancreatic cancer and may have important implications for the management of this disease.

miR-193b and miR-30c-1* inhibit, whereas miR-576-5p enhances melanoma cell invasion in vitro

In cancer cells, microRNAs (miRNAs) are often aberrantly expressed resulting in impaired mRNA translation. In this study we show that miR-193b and miR-30c-1^* inhibit, whereas miR-576-5p accelerates invasion of various human melanoma cell lines. Using Boyden chamber invasion assays the effect of selected miRNAs on the invasive capacity of various human melanoma cell lines was analyzed. Upon gene expression profiling performed on transfected A375 cells, CTGF, THBS1, STMN1, BCL9, RAC1 and MCL1 were identified as potential targets. For target validation, qPCR, Western blot analyses or luciferase reporter assays were applied. This study reveals opposed effects of miR-193b / miR-30c-1^* and miR-576-5p, respectively, on melanoma cell invasion and on expression of BCL9 and MCL1, possibly accounting for the contrasting invasive phenotypes observed in A375 cells transfected with these miRNAs. The miRNAs studied and their targets identified fit well into a model proposed by us explaining the regulation of invasion associated genes and the observed opposed phenotypes as a result of networked direct and indirect miRNA / target interactions. The results of this study suggest miR-193b and miR-30c-1^* as tumor-suppressive miRNAs, whereas miR-576-5p appears as potential tumor-promoting oncomiR. Thus, miR-193b and miR-30c-1^* mimics as well as antagomiRs directed against miR-576-5p might become useful tools in future therapy approaches against advanced melanoma.

miR-26a inhibits proliferation and promotes apoptosis in porcine immature Sertoli cells by targeting the PAK2 gene

Accumulating reports have demonstrated that microRNAs (miRNAs) participate in regulating the complex processes of animal testis development and spermatogenesis; yet, the mechanisms by which miRNAs regulate spermatogenesis are poorly understood. miR-26a was identified as a miRNA that is differentially expressed among different pig testicular tissue developmental stages in our previous study. In this study, p21 activated kinase 2 (PAK2) gene was determined as one target gene of miR-26a by luciferase reporter assay, and miR-26a repressed the PAK2 mRNA abundance in porcine Sertoli cells. The Cell Counting Kit-8 (CCK8) assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay and annexin V-FITC/PI staining assay results showed that miR-26a overexpression inhibited proliferation and promoted apoptosis in porcine Sertoli cells. These phenomena were similar to the siRNA-mediated knockdown of the PAK2 gene. Taken together, our results demonstrate that miR-26a inhibits proliferation and promotes apoptosis in porcine Sertoli cells by targeting the PAK2 gene, which may be a regulator of porcine spermatogenesis.

MicroRNA-137 dysregulation predisposes to osteoporotic fracture by impeding ALP activity and expression via suppression of leucine-rich repeat-containing G-protein-coupled receptor 4 expression

Osteoporosis is defined as a loss of bone mass and deterioration of its architecture resulting in bone weakness, which becomes prone to fracture. The objective of this study was to investigate the molecular mechanism by which miR-137 can reduce the risk of fracture in patients with osteoporosis. An online miRNA database and a luciferase reporter assay system were used to confirm that leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4) was the target of miR-137. Real-time PCR and western blot analysis were used to study miR-137 mRNA, the expression of LGR4 mRNA and protein among different groups or cells transfected with a scrambled miRNA control, miR-137 mimic, LGR4 siRNA and miR-137 inhibitor. Expression of miR-137 was upregulated to higher levels in cells isolated from osteoporosis patients with fracture than in those without fracture. The 'seed sequence' was found to be located within the 3' untranslated region (3'-UTR) of LGR4 mRNA by searching an online miRNA database. Luciferase reporter assay was performed to confirm that LGR4 is a direct target gene of miR-137 with a potential binding site in the 3'UTR of LGR4. Luciferase activity of cells transfected with wild-type LGR4 3'UTR was much lower than that of the cells transfected with mutant LGR4 3'UTR. The results of real-time PCR and immunohistochemistry experiments demonstrated that the expression levels of LGR4 mRNA and protein were much higher in osteoporosis patients with fracture than osteoporosis patients without fracture. We found that the expression levels of LGR4 mRNA and protein were clearly upregulated following transfection with miR-137 inhibitor, while noticeably downregulated following transfection with miR-137 mimic when compared with the scramble control. Furthermore, the expression of ALP mRNA and ALP activity in bone tissue were much higher in osteoporosis patients with fracture than those without fracture. In conclusion, these data prove that the overexpression of miR-137 was associated with an altered risk of fracture in patients with osteoporosis, and can be used as a biomarker for the prediction of risk of fracture in osteoporosis.

MiR-137 suppresses tumor growth and metastasis in clear cell renal cell carcinoma

BACKGROUND

The most frequent type of renal cell carcinoma is called clear-cell renal cell carcinoma (ccRCC) which is associated with a poor prognosis. It has been observed that miR-137 is aberrantly expressed in many different kinds of human malignancies including ccRCC. This research aims to examine the role of miR-137 in ccRCC.

METHODS

Quantitative RT-PCR (qRT-PCR) was applied to measure miR-137 expression in ccRCC and adjacent noncancerous tissue. Gene expression was determined by western blot. Cell Counting Kit-8 (CCK-8) assay, flow cytometry and Transwell assay were used to determine the effects of miR-137 on cell growth, apoptosis and invasion, respectively. Moreover, xenograft and pulmonary metastasis animal models were established to investigate the role of miR-137 in vivo.

RESULTS

Our findings show that there was significant downregulation of miR-137 in ccRCC tissue relative to corresponding non-cancerous tissue. Ectopic miR-137 expression in ccRCC cells led to suppression of cell growth and invasion, as well as apoptosis induction. In contrast, knockdown of miR-137 enhances proliferation and invasion, inhibits apoptosis. It also confirms that miR-137 plays a tumor supressor role in vivo. Mechanically, miR-137 directly targets the 3'-UTR of RLIP76 which is an established oncogene in ccRCC.

CONCLUSION

MiR-137 serves as a tumor suppressor, which can be considered a potential therapeutic target in ccRCC.

A comprehensive review of the genetic and biological evidence supports a role for MicroRNA-137 in the etiology of schizophrenia

Since it was first associated with schizophrenia (SCZ) in a 2011 genome-wide association study (GWAS), there have been over 100 publications focused on MIR137, the gene encoding microRNA-137. These studies have examined everything from its fundamental role in the development of mice, flies, and fish to the intriguing enrichment of its target gene network in SCZ. Indeed, much of the excitement surrounding MIR137 is due to the distinct possibility that it could regulate a gene network involved in SCZ etiology, a disease which we now recognize is highly polygenic. Here we comprehensively review, to the best of our ability, all published genetic and biological evidence that could support or refute a role for MIR137 in the etiology of SCZ. Through a careful consideration of the literature, we conclude that the data gathered to date continues to strongly support the involvement of MIR137 and its target gene network in neuropsychiatric traits, including SCZ risk. There remain, however, more unanswered than answered questions regarding the mechanisms linking MIR137 genetic variation with behavior. These questions need answers before we can determine whether there are opportunities for diagnostic or therapeutic interventions based on MIR137. We conclude with a number of suggestions for future research on MIR137 that could help to provide answers and hope for a greater understanding of this devastating disorder.

MicroRNA miR-4779 suppresses tumor growth by inducing apoptosis and cell cycle arrest through direct targeting of PAK2 and CCND3

Depending on the function of their target genes, microRNAs (miRNAs) act as either tumor suppressors or oncogenes. Therefore, miRNAs represent a novel therapeutic strategy for prevention and management of cancer by targeting of onco-miRNAs or mimicking of tumor suppressor miRNAs. Herein, we identified novel tumor suppressor miRNAs and investigated their molecular mechanisms. To identify novel tumor suppressor miRNAs, we used 532 human miRNA mimic libraries and measured cell viability using MTS assays. The function of miR-4779 was then analyzed using cell cycle analyses and apoptosis, colony forming, and soft agar assays. Target genes of miR-4779 were predicted using TargetScan and miRDB databases and were confirmed using luciferase assays. Levels of miR-4779 and target genes in colon cancer tissue samples from patients were evaluated using qRT-PCR and western blotting analyses. Finally, in vivo tumor suppressive effects of miR-4779 were evaluated in HCT116 xenografts. In this study, miR-4779 inhibited cancer cell growth by inducing apoptosis and cell cycle arrest, and the putative survival factors PAK2 and CCND3 were identified as direct targets of miR-4779. In subsequent experiments, PAK2 knockdown induced cell cycle arrest and CCND3 knockdown induced cell cycle arrest and apoptosis. In addition, miR-4779 suppressed tumor growth and tumorigenesis in an in vivo HCT116 xenograft model. Finally, miR-4779 expression was low in 9 of 10 colon cancer tissues, whereas PAK2 and CCND3 expressions were significantly high in colon cancer tissues. The novel tumor suppressor miR-4779 inhibits cancer cell growth via cell cycle arrest and apoptosis by directly targeting PAK2 and CCND3. The present data indicate the potential of miR-4779 as a therapeutic target for miRNA-based cancer therapy.

Downregulation of miR-137 and miR-6500-3p promotes cell proliferation in pediatric high-grade gliomas

Pediatric high-grade gliomas (pHGGs) are aggressive brain tumors affecting children, and outcomes have remained dismal, even with access to new multimodal therapies. In this study, we compared the miRNomes and transcriptomes of pediatric low- (pLGGs) and high-grade gliomas (pHGGs) using small RNA sequencing (smRNA-Seq) and gene expression microarray, respectively. Through integrated bioinformatics analyses and experimental validation, we identified miR-137 and miR-6500-3p as significantly downregulated in pHGGs. miR-137 or miR-6500-3p overexpression reduced cell proliferation in two pHGG cell lines, SF188 and UW479. CENPE, KIF14 and NCAPG levels were significantly higher in pHGGs than pLGGs, and were direct targets of miR-137 or miR-6500-3p. Furthermore, knockdown of CENPE, KIF14 or NCAPG combined with temozolomide treatment resulted in a combined suppressive effect on pHGG cell proliferation. In summary, our results identify novel mRNA/miRNA interactions that contribute to pediatric glioma malignancy and represent potential targets for the development of new therapeutic strategies.

The tumour suppressor, miR-137, inhibits malignant melanoma migration by targetting the TBX3 transcription factor

The transcription factor, TBX3, is a key driver of malignant melanoma and any drug that impacts its expression is likely to have an impact on the treatment of this highly aggressive and treatment resistant cancer. Replacement of miRNAs that target oncogenes has gained much attention as a therapy because it is anticipated to be effective with little side-effects since miRNAs are naturally occurring and often target large set of genes in the same oncogenic pathway. Here we show that miR-137 levels correlate inversely with TBX3 mRNA levels in a panel of melanoma cell lines and in a cohort of patients with primary melanoma. Low levels of miR-137 and high levels of TBX3 are shown to be associated with poor patient survival. We show that miR-137 binds a conserved site in the TBX3 3' untranslated region and that a miR-137 mimic significantly reduces endogenous levels of TBX3 and inhibits anchorage independent growth and migration of malignant melanoma cells. Novel data are provided that the miR-137/TBX3/E-cadherin axis plays an important role in melanomagenesis and that miR-137 replacement is a potential therapeutic approach for treating melanomas.

MicroRNA-605 functions as a tumor suppressor by targeting INPP4B in melanoma

MicroRNAs (miRNAs) play crucial roles in the initiation and progression of various cancers, including melanoma. Recently, the genetic variants and deregulation of miR-605 have been reported to participate in carcinogenesis. However, the expression status of the miR-605 in melanoma tissues and its role in melanoma progression remain unknown. In this study, we found that miR-605 was significantly downregulated in melanoma cell lines and clinical specimens. Further function studies demonstrated that miR-605 suppressed melanoma cell growth both in vitro and in vivo. Moreover, INPP4B gene was identified as a target of miR-605 through bioinformatics analysis and luciferase reporter assays. Further analysis demonstrated that the inhibition of INPP4B mediated SGK3 activation was required for the suppressive role of miR-605 on melanomas cell growth. Collectively, our data suggest that miR-605 functions as a tumor suppressor by negatively regulating INPP4B mediated SGK3 activation in melanoma and may present a potential target for therapeutic intervention.

MiR-137: an important player in neural development and neoplastic transformation

MicroRNAs (miRNAs) represent an important class of small regulatory RNAs that control gene expression posttranscriptionally by targeting mRNAs for degradation or translation inhibition. Early studies have revealed a complex role for miRNAs in major biological processes such as development, differentiation, growth and metabolism. MiR-137 in particular, has been of great interest due to its critical role in brain function and putative involvement in the etiology of both neuropsychiatric disorders and cancer. Several lines of evidence suggest that development, differentiation and maturation of the nervous system is strongly linked to the expression of miR-137 and its regulation of a large number of downstream target genes in various pathways. Dysregulation of this molecule has also been implicated in major mental illnesses through its position in a variant allele highly associated with schizophrenia in the largest mega genome-wide association studies. Interestingly, miR-137 has also been shown to act as a tumor suppressor, with numerous studies finding reduced expression in neoplasia including brain tumor. Restoration of miR-137 expression has also been shown to inhibit cell proliferation, migration and metastasis, and induce cell cycle arrest, differentiation and apoptosis. These properties of miR-137 propose its potential for prognosis, diagnosis and as a therapeutic target for treatment of several human neurological and neoplastic disorders. In this review, we provide details on the discovery, targets, function, regulation and disease involvement of miR-137 with a broad look at recent discovery in this area.

Structure, biochemistry, and biology of PAK kinases

PAKs, p21-activated kinases, play central roles and act as converging junctions for discrete signals elicited on the cell surface and for a number of intracellular signaling cascades. PAKs phosphorylate a vast number of substrates and act by remodeling cytoskeleton, employing scaffolding, and relocating to distinct subcellular compartments. PAKs affect wide range of processes that are crucial to the cell from regulation of cell motility, survival, redox, metabolism, cell cycle, proliferation, transformation, stress, inflammation, to gene expression. Understandably, their dysregulation disrupts cellular homeostasis and severely impacts key cell functions, and many of those are implicated in a number of human diseases including cancers, neurological disorders, and cardiac disorders. Here we provide an overview of the members of the PAK family and their current status. We give special emphasis to PAK1 and PAK4, the prototypes of groups I and II, for their profound roles in cancer, the nervous system, and the heart. We also highlight other family members. We provide our perspective on the current advancements, their growing importance as strategic therapeutic targets, and our vision on the future of PAKs.

MiR-769 promoted cell proliferation in human melanoma by suppressing GSK3B expression

MicroRNAs (miRNAs) are short, non-coding RNAs with post-transcriptional regulatory function, playing crucial roles in cancer development and progression of human melanoma. Previous studies have indicated that miR-769 was implicated in diverse biological processes. However, the underlying mechanism of miR-769 in human melanoma has not been intensively investigated. In this present study, we aimed to investigate the role of miR-769 and its target genes in human melanoma. We found that miR-769 expression was strongly increased in human melanoma cells and clinical tissues compared with their corresponding controls. Overexpression of miR-769 promoted cell proliferation in human melanoma cell line A375, whereas miR-769-in reverses the function. Glycogen synthase kinase-3 Beta (GSK3B), a potential target gene of miR-769, and was validated by luciferase assay. Further studies revealed that miR-769 regulated cell proliferation of human melanoma by directly suppressing GSK3B expression and the knockdown of GSK3B expression reversed the effect of miR-769-in on human melanoma cell proliferation. In summary, our data demonstrated that miR-769 might act as a tumor promoter by targeting GSK3B during development of human melanoma.

Proteomic Findings in Melanoma

Although the emergence of proteomics as an independent branch of science is fairly recent, within a short period of time it has contributed substantially in various disciplines. The tool of mass spectrometry has become indispensable in the analysis of complex biological samples. Clinical applications of proteomics include detection of predictive and diagnostic markers, understanding mechanism of action of drugs as well as resistance mechanisms against them and assessment of therapeutic efficacy and toxicity of drugs in patients. Here, we have summarized the major contributions of proteomics towards the study of melanoma, which is a deadly variety of skin cancer with a high mortality rate.

PAKs in Human Cancer Progression: From Inception to Cancer Therapeutic to Future Oncobiology

Since the initial recognition of a mechanistic role of p21-activated kinase 1 (PAK1) in breast cancer invasion, PAK1 has emerged as one of the widely overexpressed or hyperactivated kinases in human cancer at-large, allowing the PAK family to make in-roads in cancer biology, tumorigenesis, and cancer therapeutics. Much of our current understanding of the PAK family in cancer progression relates to a central role of the PAK family in the integration of cancer-promoting signals from cell membrane receptors as well as function as a key nexus-modifier of complex, cytoplasmic signaling network. Another core aspect of PAK signaling that highlights its importance in cancer progression is through PAK's central role in the cross talk with signaling and interacting proteins, as well as PAK's position as a key player in the phosphorylation of effector substrates to engage downstream components that ultimately leads to the development cancerous phenotypes. Here we provide a comprehensive review of the recent advances in PAK cancer research and its downstream substrates in the context of invasion, nuclear signaling and localization, gene expression, and DNA damage response. We discuss how a deeper understanding of PAK1's pathobiology over the years has widened research interest to the PAK family and human cancer, and positioning the PAK family as a promising cancer therapeutic target either alone or in combination with other therapies. With many landmark findings and leaps in the progress of PAK cancer research since the infancy of this field nearly 20 years ago, we also discuss postulated advances in the coming decade as the PAK family continues to shape the future of oncobiology.