Downregulation of METTL6 mitigates cell progression, migration, invasion and adhesion in hepatocellular carcinoma by inhibiting cell adhesion molecules

RNA modifications have attracted increasing interest in recent years because they have been frequently implicated in various human diseases, including cancer, highlighting the importance of dynamic post‑transcriptional modifications. Methyltransferase‑like 6 (METTL6) is a member of the RNA methyltransferase family that has been identified in many cancers; however, little is known about its specific role or mechanism of action. In the present study, we aimed to study the expression levels and functional role of METTL6 in hepatocellular carcinoma (HCC), and further investigate the relevant pathways. To this end, we systematically conducted bioinformatics analysis of METTL6 in HCC using gene expression data and clinical information from a publicly available dataset. The mRNA expression levels of METTL6 were significantly upregulated in HCC tumor tissues compared to that in adjacent non‑tumor tissues and strongly associated with poorer survival outcomes in patients with HCC. CRISPR/Cas9‑mediated knockout of METTL6 in HCC cell lines remarkably inhibited colony formation, cell proliferation, cell migration, cell invasion and cell attachment ability. RNA sequencing analysis demonstrated that knockout of METTL6 significantly suppressed the expression of cell adhesion‑related genes. However, chromatin immunoprecipitation sequencing results revealed no significant differences in enhancer activities between cells, which suggests that METTL6 may regulate genes of interest post‑transcriptionally. In addition, it was demonstrated for the first time that METTL6 was localized in the cytosol as detected by immunofluorescence analysis, which indicates the plausible location of RNA modification mediated by METTL6. Our findings provide further insight into the function of RNA modifications in cancer and suggest a possible role of METTL6 as a therapeutic target in HCC.

Unfolding individual als5p adhesion proteins on live cells

Elucidating the molecular mechanisms behind the strength and mechanics of cell adhesion proteins is of central importance in cell biology and offers exciting avenues for the identification of potential drug targets. Here we use single-molecule force spectroscopy to investigate the adhesive and mechanical properties of the widely expressed Als5p cell adhesion protein from the opportunistic pathogen Candida albicans . We show that the forces required to unfold individual tandem repeats of the protein are in the 150-250 pN range, both on isolated molecules and on live cells. We also find that the unfolding probability increases with the number of tandem repeats and correlates with the level of cell adherence. We suggest that the modular and flexible nature of Als5p conveys both strength and toughness to the protein, making it ideally suited for cell adhesion. The single-molecule measurements presented here open new avenues for understanding the mechanical properties of adhesion molecules from mammalian and microbial cells and may help us to elucidate their potential implications in diseases such as inflammation, cancer, and infection.