PTBP1 promotes the progression of hepatocellular carcinoma by enhancing the oncogenic splicing switch of FGFR2.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer accounting for 90% of cases. It is a highly invasive and deadly cancer with a gradual onset. Polypyrimidine tract-binding protein 1 (PTBP1) is an important RNA-binding protein involved in RNA metabolism and has been linked to oncogenic splicing events. While the oncogenic role of PTBP1 in HCC cells has been established, the exact mechanism of action remains unclear. This study aimed to investigate the functional connection between PTBP1 and dysregulated splicing events in HCC. Through immunoprecipitation-mass spectrometry analyses, we discovered that the proteins bound to PTBP1 were significantly enriched in the complex responsible for the alternative splicing of FGFR2 (fibroblast growth factor receptor 2). Further RNA immunoprecipitation and quantitative PCR assays confirmed that PTBP1 down-regulated the FGFR2-IIIb isoform levels and up-regulated the FGFR2-IIIc isoform levels in HCC cells, leading to a switch from FGFR2-IIIb to FGFR2-IIIc isoforms. Subsequent functional evaluations using CCK-8, transwell, and plate clone formation assays in HCC cell lines HepG2 and Huh7 demonstrated that FGFR2-IIIb exhibited tumor-suppressive effects, while FGFR2-IIIc displayed tumor-promoting effects. In conclusion, this study provides insights into the PTBP1-mediated alternative splicing mechanism in HCC progression, offering a new theoretical basis for the prevention and treatment of this malignancy. Mechanistically, the isoform switch from FGFR2-IIIb to FGFR2-IIIc promoted epithelial-mesenchymal transformation (EMT) of HCC cells and activated the FGFR cascades ERK and AKT pathways.

Prognostic and predictive value of the hypoxia-associated long non-coding RNA signature in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a common cancer worldwide. Hypoxia is an important feature of solid tumors, including HCC, and is also an important factor involved in malignancy progression. However, the identification of hypoxia-related long non-coding RNA (lncRNAs) and their prognostic value in HCC have not been systematically investigated. The aim of this study is to identify the features based on the hypoxia-related lncRNAs and evaluate their predictive value for HCC prognosis. Based on the integrated analysis of HCC transcriptome data from The Cancer Genome Atlas (TCGA), we had identified 233 potential hypoxia-related lncRNAs. We further evaluated the prognostic value of these lncRNAs and optimally established a 12-lncRNA (AC012676.1, PRR7-AS1, AC020915.2, AC008622.2, AC026401.3, MAPKAPK5-AS1, MYG1-AS1, AC015908.3, AC009275.1, MIR210HG, CYTOR and SNHG3) prognostic risk model. The Cox proportional hazards regression analysis revealed that the hypoxia risk score is a novel independent prognostic predictor for HCC patients, which outperforms the traditional clinical pathological factors. Gene set enrichment analysis (GSEA) showed that the hypoxia risk score reflects the activation of biological features related to cell proliferation and the inactivation of lipid metabolism processes. In summary, we had constructed a risk score model based on 12 hypoxia-related lncRNAs, which might be a promising prognostic predictor for HCC patients and highlight their potential roles in the prevention and treatment of this malignancy.

Prognostic and predictive value of a DNA methylation-driven transcriptional signature in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. DNA methylation alterations are frequently observed in malignant tumours and play critical roles in the development of cancers, including HCC. To provide novel clinical prognosis biomarkers for HCC patients, we first performed a comprehensive analysis and identified a collection of prognosis-associated genes with DNA methylation-driven expression dysregulation in HCCs. Then, we optimally established a 10-gene prognostic risk score model using the least absolute shrinkage and selection operator (LASSO) analysis. Cox's proportional hazards regression analysis revealed that the high-risk score is significantly associated with poor prognosis after being adjusted by clinical parameters, indicating its potential prognostic value. The receiver operating characteristic curve (ROC) analysis showed that this 10-gene prognostic risk score model outperformed several other publicly available models in predicting both short- and long-term prognosis. Gene set enrichment analysis revealed that the high-risk score is relevantly associated with pathways involved in cell cycle and DNA damage repair. The above results indicate that we have constructed a 10-DNA-methylation-driven-gene prognostic risk score model, which might serve as a potential prognostic biomarker for HCC patients and guide treatment decisions for patients at high risk of tumour progression.

Aberrant high expression level of MORC2 is a common character in multiple cancers.

Microrchidia 2 (MORC2) plays important roles in DNA damage repair and lipogenesis, but the clinical and functional role of MORC2 in cancer remains largely unexplored. In this study, we showed that MORC2 was widely expressed in human tissues while significantly up-regulated in most cancer types using immunohistochemical staining and analysis of messenger RNA expression profile of more than 2000 human tissue samples from 15 different organs (lung, prostate, liver, breast, brain, stomach, colon/rectum, pancreas, ovary, endometrium, skin, nasopharynx, kidney, esophagus, and bladder). We also found that the MORC2 expression level in high-grade cancer tissues was much more elevated and associated with unfavorable pathological characteristics, poor overall survival, and disease-free survival in several kinds of cancers such as non-small cell lung cancer and breast cancer. Gene set enrichment analysis was used to predict the genes modulated by MORC2, and the results showed that dysregulation of MORC2 in tumor may take part in the cell cycle regulation and genomic instability. We observed that MORC2 knockdown would arrest the cell cycle progress, and the genome of tumors with high MORC2 expression contained more point mutations and gene copy number variation, which validates our gene set enrichment analysis results. The results also showed that MORC2 knockdown would significantly inhibit the proliferation, colony forming, migration, and invasion in multiple cancer cell lines. Taken together, these results highlight the importance of MORC2 in tumorigenesis and cancer progression, and it may act as a potential diagnostic marker and therapeutic target for these diseases.

[Research advances on medical genetics in China in 2015].

Steady progress has been achieved in the medical genetics in China in 2015, as numerous original researches were published in the world's leading journals. Chinese scientists have made significant contributions to various fields of medical genetics, such as pathogenicity of rare diseases, predisposition of common diseases, somatic mutations of cancer, new technologies and methods, disease-related microRNAs (miRNAs), disease-related long non-coding RNAs (lncRNAs), disease-related competing endogenous RNAs (ceRNAs), disease-related RNA splicing and molecular evolution. In these fields, Chinese scientists have gradually formed the tendency, from common variants to rare variants, from single omic analyses to multipleomics integration analyses, from genetic discovery to functional confirmation, from basic research to clinical application. Meanwhile, the findings of Chinese scientists have been drawn great attentions of international peers. This review aims to provide an overall picture of the front in Chinese medical genetics, and highlights the important findings and their research strategy.