Decreased Expression of Long Non-Coding RNA GMDS Divergent Transcript (GMDS-DT) is a Potential Biomarker for Poor Prognosis of Hepatocellular Carcinoma

Long-read sequencing reveals oncogenic mechanism of HPV-human fusion transcripts in cervical cancer

Integration of high-risk human papillomavirus (HPV) into the host genome is a crucial event for the development of cervical cancer, however, the underlying mechanism of HPV integration-driven carcinogenesis remains unknown. Here, we performed long-read RNA sequencing on 12 high-grade squamous intraepithelial lesions (HSIL) and cervical cancer patients, including 3 pairs of cervical cancer and corresponding para-cancerous tissue samples to investigate the full-length landscape of cross-species genome integrations. In addition to massive unannotated isoforms, transcriptional regulatory events, and gene chimerism, more importantly, we found that HPV-human fusion events were prevalent in HPV-associated cervical cancers. Combined with the genome data, we revealed the existence of a universal transcription pattern in these fusion events, whereby structurally similar fusion transcripts were generated by specific splicing in E6 and a canonical splicing donor site in E1 linking to various human splicing acceptors. Highly expressed HPV-human fusion transcripts, eg, HPV16 E6*I-E7-E1_SD880-human gene, were the key driver of cervical carcinogenesis, which could trigger overexpression of E6*I and E7, and destroy the transcription of tumor suppressor genes CMAHP, TP63 and P3H2. Finally, evidence from in vitro and in vivo experiments demonstrates that the novel read-through fusion gene mRNA, E1-CMAHP (E1C, formed by the integration of HPV58 E1 with CMAHP), existed in the fusion transcript can promote malignant transformation of cervical epithelial cells via regulating downstream oncogenes to participate in various biological processes. Taken together, we reveal a previously unknown mechanism of HPV integration-driven carcinogenesis and provide a novel target for the diagnosis and treatment of cervical cancer.

Prognostic Value of Macrophage-Associated Long Non-Coding RNA Expression for Hepatocellular Carcinoma

Background

There is ample evidence that macrophages play a crucial role in the biological processes of hepatocellular carcinoma (HCC). This study was designed to establish a novel macrophage-associated prognostic model for HCC.

Methods

Long non-coding RNA (lncRNA) microarrays and clinical data in The Cancer Genome Atlas (TCGA) database were analysed using a univariate Cox proportional regression model to select macrophage-associated prognostic lncRNAs. Multivariate Cox proportional regression models and survival analysis were used to establish a prognosis index (PI) model. Furthermore, to better understand the biological functions of differentially expressed macrophage-associated lncRNAs (MALs) in HCC, enrichment analysis was performed. Finally, the correlation between MALs and clinical features was further analysed in HCC.

Results

We identified eight MALs with significant prognostic values for HCC. Next, a PI model for HCC was developed, and patients were classified into the high-risk or low-risk group based on risk scores. The overall survival (OS) of high-risk patients was significantly shorter than that of low-risk patients (P < 0.001). Univariate and multivariate factors indicate that risk scores can be used as independent prognostic factors for patients with HCC. Multiple receiver operating characteristic (ROC) plots show that the area under the ROC curve (AUC) of the risk score is higher than that of other clinical features. The C-index of our nomogram was 0.768.

Conclusion

The PI model has a prognostic efficacy superior to that of other clinical features.

Comparison of structural variants detected by optical mapping with long-read next-generation sequencing

MOTIVATION

Recent studies have shown the potential of using long-read whole-genome sequencing (WGS) approaches and optical mapping (OM) for the detection of clinically relevant structural variants (SVs) in cancer research. Three main long-read WGS platforms are currently in use: Pacific Biosciences (PacBio), Oxford Nanopore Technologies (ONT) and 10x Genomics. Recently, whole-genome OM technology (Bionano Genomics) has been introduced into human diagnostics. Questions remain about the accuracy of these long-read sequencing platforms, how comparable/interchangeable they are when searching for SVs and to what extent they can be replaced or supplemented by OM. Moreover, no tool can effectively compare SVs obtained by OM and WGS.

RESULTS

This study compared optical maps of the breast cancer cell line SKBR3 with AnnotSV outputs from WGS platforms. For this purpose, a software tool with comparative and filtering features was developed. The majority of SVs up to a 50 kbp distance variance threshold found by OM were confirmed by all WGS platforms, and 99% of translocations and 80% of deletions found by OM were confirmed by both PacBio and ONT, with ∼70% being confirmed by 10x Genomics in combination with PacBio and/or ONT. Interestingly, long deletions (>100 kbp) were detected only by 10x Genomics. Regarding insertions, ∼72% was confirmed by PacBio and ONT, but none by 10x Genomics. Inversions and duplications detected by OM were not detected by WGS. Moreover, the tool enabled the confirmation of SVs that overlapped in the same gene(s) and was applied to the filtering of disease-associated SVs.

AVAILABILITY

https://github.com/novosadt/om-annotsv-svc.

The mechanistic, diagnostic and therapeutic novel nucleic acids for hepatocellular carcinoma emerging in past score years

Despite The Central Dogma states the destiny of gene as 'DNA makes RNA and RNA makes protein', the nucleic acids not only store and transmit genetic information but also, surprisingly, join in intracellular vital movement as a regulator of gene expression. Bioinformatics has contributed to knowledge for a series of emerging novel nucleic acids molecules. For typical cases, microRNA (miRNA), long noncoding RNA (lncRNA) and circular RNA (circRNA) exert crucial role in regulating vital biological processes, especially in malignant diseases. Due to extraordinarily heterogeneity among all malignancies, hepatocellular carcinoma (HCC) has emerged enormous limitation in diagnosis and therapy. Mechanistic, diagnostic and therapeutic nucleic acids for HCC emerging in past score years have been systematically reviewed. Particularly, we have organized recent advances on nucleic acids of HCC into three facets: (i) summarizing diverse nucleic acids and their modification (miRNA, lncRNA, circRNA, circulating tumor DNA and DNA methylation) acting as potential biomarkers in HCC diagnosis; (ii) concluding different patterns of three key noncoding RNAs (miRNA, lncRNA and circRNA) in gene regulation and (iii) outlining the progress of these novel nucleic acids for HCC diagnosis and therapy in clinical trials, and discuss their possibility for clinical applications. All in all, this review takes a detailed look at the advances of novel nucleic acids from potential of biomarkers and elaboration of mechanism to early clinical application in past 20 years.