AXIN1 protects against testicular germ cell tumors via the PI3K/AKT/mTOR signaling pathway

Silencing of LINC00467 inhibits cell proliferation in testicular germ cell tumors cells

A significant decrease in LINC00467 expression in testicular germ cell tumors (TGCTs) was found in our previous study in comparison to adjacent tissue. Interestingly, the expression of LINC00467 correlated with the pathological grade of the tumor in TGCT patients. The higher the expression of LINC00467 was, the worse the prognosis of the patients with TGCT was. Despite these findings, the exact role of LINC00467 in the development of TGCTs requires further investigation. LINC00467 expression was downregulated in the NCCIT and TCam-2 cell lines via small interfering RNA (siRNA) silencing. The levels of gene expression were validated using quantitative real-time polymerase chain reaction (qRT-PCR) analyses. Cell proliferation was evaluated by the MTT and Cell Counting Kit-8 (CCK8) assays, whereas flow cytometry was used to assess the effects on the cell cycle. Western blotting analysis was used to detect expression levels of protein. Additionally, RNA-sequencing and bioinformatics methods were used to investigate the mechanism of action of LINC00467 in TGCTs. The suppression of LINC00467 expression resulted in decreased cell proliferation and induced S-phase arrest. Furthermore, the suppression of LINC00467 downregulated proliferating cell nuclear antigen (PCNA), a protein related to cell cycle regulation, while it upregulated p21 expression. In other studies involving dihydrotestosterone (DHT) stimulation, it was observed that DHT could upregulate LINC00467 expression. In addition, silencing of the LINC00467 reversed the effect of testosterone on cell proliferation. The Gene Set Enrichment Analysis (GSEA) revealed that LINC00467 regulated the p53 pathway by modulating the expression of CCNG1. Our study found that LINC00467 regulates cell proliferation by inducing S-phase arrest through the cell cycle-related proteins PCNA and p21. These findings contribute to our understanding of non-coding RNAs mechanisms involved in the development of TGCTs.

Loss of liver kinase B1 in human seminoma

Testicular cancer is a common malignancy of young males and is believed to be originated from defective embryonic or adult germ cells. Liver kinase B1 (LKB1) is a serine/threonine kinase and a tumor suppressor gene. LKB1 is a negative regulator of the mammalian target of rapamycin (mTOR) pathway, often inactivated in many human cancer types. In this study, we investigated the involvement of LKB1 in the pathogenesis of testicular germ cell cancer. We performed immunodetection of LKB1 protein in human seminoma samples. A 3D culture model of human seminoma was developed from TCam-2 cells, and two mTOR inhibitors were tested for their efficacy against these cancer cells. Western blot and mTOR protein arrays were used to show that these inhibitors specifically target the mTOR pathway. Examination of LKB1 showed reduced expression in germ cell neoplasia in situ lesions and seminoma compared to adjacent normal-appearing seminiferous tubules where the expression of this protein was present in the majority of germ cell types. We developed a 3D culture model of seminoma using TCam-2 cells, which also showed reduced levels of LKB1 protein. Treatment of TCam-2 cells in 3D with two well-known mTOR inhibitors resulted in reduced proliferation and survival of TCam-2 cells. Overall, our results support that downregulation or loss of LKB1 marks the early stages of the pathogenesis of seminoma, and the suppression of downstream signaling to LKB1 might be an effective therapeutic strategy against this cancer type.

A Random Forest-Based Genome-Wide Scan Reveals Fertility-Related Candidate Genes and Potential Inter-Chromosomal Epistatic Regions Associated With Age at First Calving in Nellore Cattle

This study aimed to perform a genome-wide association analysis (GWAS) using the Random Forest (RF) approach for scanning candidate genes for age at first calving (AFC) in Nellore cattle. Additionally, potential epistatic effects were investigated using linear mixed models with pairwise interactions between all markers with high importance scores within the tree ensemble non-linear structure. Data from Nellore cattle were used, including records of animals born between 1984 and 2015 and raised in commercial herds located in different regions of Brazil. The estimated breeding values (EBV) were computed and used as the response variable in the genomic analyses. After quality control, the remaining number of animals and SNPs considered were 3,174 and 360,130, respectively. Five independent RF analyses were carried out, considering different initialization seeds. The importance score of each SNP was averaged across the independent RF analyses to rank the markers according to their predictive relevance. A total of 117 SNPs associated with AFC were identified, which spanned 10 autosomes (2, 3, 5, 10, 11, 17, 18, 21, 24, and 25). In total, 23 non-overlapping genomic regions embedded 262 candidate genes for AFC. Enrichment analysis and previous evidence in the literature revealed that many candidate genes annotated close to the lead SNPs have key roles in fertility, including embryo pre-implantation and development, embryonic viability, male germinal cell maturation, and pheromone recognition. Furthermore, some genomic regions previously associated with fertility and growth traits in Nellore cattle were also detected in the present study, reinforcing the effectiveness of RF for pre-screening candidate regions associated with complex traits. Complementary analyses revealed that many SNPs top-ranked in the RF-based GWAS did not present a strong marginal linear effect but are potentially involved in epistatic hotspots between genomic regions in different autosomes, remarkably in the BTAs 3, 5, 11, and 21. The reported results are expected to enhance the understanding of genetic mechanisms involved in the biological regulation of AFC in this cattle breed.

Arginyl-tRNA-protein transferase 1 (ATE1) promotes melanoma cell growth and migration

Arginyl-tRNA-protein transferase 1 (ATE1) catalyses N-terminal protein arginylation, a post-translational modification implicated in cell migration, invasion and the cellular stress response. Herein, we report that ATE1 is overexpressed in NRAS-mutant melanomas, while it is downregulated in BRAF-mutant melanomas. ATE1 expression was higher in metastatic tumours, compared with primary tumours. Consistent with these findings, ATE1 depletion reduced melanoma cell viability, migration and colony formation. Reduced ATE1 expression also affected cell responses to mTOR and MEK inhibitors and to serum deprivation. Among putative ATE1 substrates is the tumour suppressor AXIN1, pointing to the possibility that ATE1 may fine-tune AXIN1 function in melanoma. Our findings highlight an unexpected role for ATE1 in melanoma cell aggressiveness and suggest that ATE1 constitutes a potential new therapeutic target.

Localisation and in silico based functional analysis of miR-202 in bull testis

Bull fertility is pivotal to the prosperity of the cattle industry worldwide. miR‐202 has been shown to be gonad specific and to have key roles in gonad function in different species. To further understand the involvement of miR‐202 in bull reproduction, this study aimed to establish its localization in bovine testicular tissue and to identify putative biological functions using bioinformatics approaches. We assessed the miR‐202 expression in paraffin‐embedded tissue samples collected form an abattoir using in situ hybridization. miR‐202 was present in Sertoli cells and in germ cells at different stages of development. Using available databases, a total of 466 predicted gene targets of miR‐202 were identified. Functional annotation revealed that miR‐202 target genes were mainly associated with protein modification and phosphorylation processes as well as longevity regulating pathway. Moreover, genes in the longevity regulating pathway mapped to PI3K/Akt/mTOR pathway which is involved in promoting proliferation of testicular cells and spermatogenesis. These findings suggest that miR‐202 plays important roles in regulating proliferation and viability of testicular cells including somatic and germ cells.

Role of PI3K/AKT pathway in cancer: the framework of malignant behavior

Given that the PI3K/AKT pathway has manifested its compelling influence on multiple cellular process, we further review the roles of hyperactivation of PI3K/AKT pathway in various human cancers. We state the abnormalities of PI3K/AKT pathway in different cancers, which are closely related with tumorigenesis, proliferation, growth, apoptosis, invasion, metastasis, epithelial-mesenchymal transition, stem-like phenotype, immune microenvironment and drug resistance of cancer cells. In addition, we investigated the current clinical trials of inhibitors against PI3K/AKT pathway in cancers and found that the clinical efficacy of these inhibitors as monotherapy has so far been limited despite of the promising preclinical activity, which means combinations of targeted therapy may achieve better efficacies in cancers. In short, we hope to feature PI3K/AKT pathway in cancers to the clinic and bring the new promising to patients for targeted therapies.

The Clinicopathological Features and Genetic Mutations in Gastric Cancer Patients According to EMAST and MSI Status

Background: There has been no report regarding the clinicopathological features and genetic mutations regarding elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) in gastric cancer (GC). Methods: The correlation among EMAST status, microsatellite instability (MSI) status, mutations of common GC-related genes and 16 DNA repair-associated genes, and the clinicopathological features were analyzed. Results: Among the 360 GC patients enrolled, there were 76 (21.1%) with EMAST+ tumors and 284 with EMAST− tumors, and 59 (16.4%) were MSI-high (MSI-H) tumors, and 301 were microsatellite stable (MSS) tumors. Patients with EMAST+ tumors exhibited an earlier pathological T category and had more genetic mutations in the PI3K/AKT pathway, ARID1A and DNA repair-associated genes than those with EMAST− tumors. Patients with MSI-H tumors have more genetic mutations in the PI3K/AKT pathway and DNA repair-associated genes than those with MSS tumors. In the subgroup analysis for MSI-H GC, EMAST+ tumors were associated with earlier pathological T and N categories, earlier TNM stages, higher frequency of DNA-repair-associated genetic mutations, and a better survival rate than EMAST− tumors. Conclusions:PI3K/AKT pathway mutations may play an important role in EMAST+ and/or MSI-H GC. EMAST+/MSI-H tumors seem to represent a different subtype of gastric cancer from EMAST−/MSI-H tumors.

Down-regulation of microRNA-31-5p inhibits proliferation and invasion of osteosarcoma cells through Wnt/β-catenin signaling pathway by enhancing AXIN1

OBJECTIVES

Recently, the role of microRNA-31-5p (miR-31-5p) in gene expression regulation has been reported in various cancers. Studies have shown that Wnt/β-catenin signaling pathway is involved in the proliferation and invasion of osteosarcoma (OS) cells. Therefore, this study aims to probe into the regulatory role of miR-31-5p targeting AXIN1 in OS cells through Wnt/β-catenin signaling pathway.

METHODS

Firstly, microarray expression profiles were used to screen differentially expressed miRNAs associated with OS. Next, OS and normal fibrous connective tissues as well as OS cell lines were obtained for investigating the role of miR-31-5p on OS. Then, the putative binding sites between miR-31-5p and AXIN1 were predicted and verified. The regulatory effects of miR-31-5p on proliferation and invasion as well as tumorigenic potential of OS cells targeting AXIN1 were also analyzed. Besides, the relationship between miR-31-5p and Wnt/β-catenin signaling pathway was assessed by immunofluorescence staining.

RESULTS

The microarray dataset GSE63939 showed that miR-31-5p and AXIN1 were involved in OS. miR-31-5p expression increased while the expression of AXIN1 decreased in OS tissues and cells. AXIN1 was identified as a target gene of miR-31-5p, intense expression of which inhibited the transcription of AXIN1. Down-regulated miR-31-5p suppressed proliferation, invasion and tumorigenicity of OS cells through promoting AXIN1. Decreased miR-31-5p activated Wnt/β-catenin signaling pathway, as reflected by increased β-catenin translocation into nuclei, through up-regulating the transcription of AXIN1.

CONCLUSIONS

All in all, repression of miR-31-5p targets AXIN1 to activate the Wnt/β-catenin signaling pathway, thus suppressing proliferation, invasion and tumorigenicity of OS cells.

Quercetin inhibits renal cyst growth in vitro and via parenteral injection in a polycystic kidney disease mouse model

Autosomal dominant polycystic kidney disease (ADPKD) is a common monogenic disease characterized by massive enlargement of fluid-filled cysts in the kidney.