Transcriptome Mapping of the Internal N7-Methylguanosine Methylome in Messenger RNAs in Human Oral Squamous Cell Carcinoma

BACKGROUND

Internal N7-methylguanosine (m7G) methylation in mammalian messenger RNAs (mRNAs) is essential in disease development. However, the status of internally m7G-modified mRNAs in oral squamous cell carcinoma (OSCC) remains poorly understood.

METHODS

Methylated RNA immunoprecipitation sequencing (MeRIP-seq) was used to identify the m7G modification level of mRNAs and the expression of mRNAs between OSCC and normal tissues. These differentially methylated and expressed genes were subjected to Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and construction of protein-protein interaction (PPI) networks. Quantitative real-time PCR (qPCR) assay was performed to detect the expression of Baculoviral IAP Repeat Containing 3 (BIRC3) in vitro. The biological function of BIRC3 in OSCC was clarified using CCK-8, Transwell migration and Western blot assays.

RESULTS

The m7G-mRNA profile showed 9514 unique m7G peaks within 7455 genes in OSCC tissues. In addition, the most conserved m7G motif within mRNAs in OSCC was GGARG (R = G/A). The identified m7G peaks were mainly distributed in the coding sequence region within mRNAs in OSCC. GO enrichment and KEGG pathway analyses showed that m7G-modified genes were closely related to cancer progression. m7G-modified hub genes were screened from the constructed PPI networks. Furthermore, BIRC3 with high m7G methylation showed high expression in OSCC cell lines, as confirmed by qPCR assay. Functionally, the knockdown of BIRC3 significantly inhibited the proliferation and migration ability of CAL-27 cells in vitro functional assays. In addition, the relative expression of E-cadherin expression was elevated, while Vimentin and N-cadherin protein expression was decreased in CAL-27 cells transfected with si-BIRC3. This study suggests that BIRC3 could promote OSCC proliferation and migration, which may be associated with involvement in epithelial-mesenchymal transition (EMT) progression.

CONCLUSIONS

This paper constructed a transcriptome map of internal m7G in mRNAs, which provides potential research value to study the role of m7G methylation in OSCC.

ENAH-202 promotes cancer progression in oral squamous cell carcinoma by regulating ZNF502/VIM axis

BACKGROUND

We aimed to demonstrate the regulatory effect of long non-coding RNA (lncRNA) ENAH-202 on oral squamous cell carcinoma (OSCC) development as well as its molecular mechanism.

METHODS

We detected ENAH-202 expression in OSCC tissues and cell lines by quantitative real-time PCR (qPCR). The biological function of ENAH-202 was assessed in vitro and in vivo using CCK-8, colony formation assays, transwell assays, xenograft formation, and tail vein injection. The further molecular mechanism by which ENAH-202 promoted OSCC progression was identified using RNA pull-down, LS-MS/MS analysis, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) assays.

RESULTS

ENAH-202 was significantly upregulated in OSCC tissues and cells. ENAH-202 promoted OSCC cell proliferation, migration, and invasion in vitro and in vivo. The expression of enabled homolog (ENAH) and epithelial-to-mesenchymal transition (EMT)-related proteins was changed with the expression of ENAH-202. Moreover, ENAH-202 promoted the transcription of Vimentin (VIM) by binding with ZNF502, which can help ENAH-202 promote OSCC progression.

CONCLUSIONS

ENAH-202 facilitated OSCC cell proliferation and metastasis by regulating ZNF502/VIM axis, which played an important role in OSCC progression.

[Disease burden and prediction of oral cancer attributable to smoking in China from 1990 to 2019]

Objective: To analyze the trend of disease burden of oral cancer attributable to smoking in China from 1990 to 2019, and predict the mortality trend of oral cancer from 2020 to 2034, providing scientific basis for formulating targeted oral cancer prevention and treatment strategy to achieve the goal of "Healthy China 2030". Methods: Using partial data on the global burden of disease in China in 2019, attributive death and disability adjusted life year (DALY) were used to describe. The trend of changes in the burden of oral cancer disease attributed to smoking was analyzed by using the Joinpoint regression model to estimate the annual average percentage change (AAPC) of age standardized mortality and DALY rates. Meanwhile, the Bayesian age-period- cohort model is used to predict oral cancer deaths and DALY trends attributed to smoking over the next 15 years. Results: The age-standardized mortality rate and DALY rate in China from 1990 to 2019 showed an overall upward trend, with an average annual increase of 1.49% (95%CI: 1.34%-1.65%, P<0.001) and 1.41% (95%CI: 1.24%-1.59%, P<0.001) respectively, higher than around the earth and in regions with different socio-demographic index (SDI). In 2019, 46.74% (10 584/22 642) of oral cancer deaths in China were attributed to smoking. Compared to 1990, the number of attributed deaths in 2019 increased by 293.75% (7 896/2 688), while DALY increased by 257.97% (189 039/73 280). Moreover, the growth rates of attributed deaths and DALY in males [304.95% (7 584/2 487) and 265.60% (183 349/69 033), respectively] were significantly higher than those in females [154.73% (311/201) and 133.95% (5 690/4 248), respectively] (P<0.001). The age group results showed that the proportion of deaths and DALY gradually transitioned towards the elderly (>60 years old). The expected number of deaths would increase from 10 731 in 2020 to 14 125 in 2034, with a rise of 31.63% (3 394/10 731). Simultaneously, DALY would increase from 267 064 person years in 2020 to 326 634 person years in 2034, with a rise of 22.31% (59 570/267 064). Conclusions: From 1990 to 2019, the burden of oral cancer diseases attributed to smoking in China showed an increasing trend, with a higher growth rates than in the global and different SDI regions. There were differences in gender and age, and the burden of oral cancer diseases attributed to smoking in China would continue to increase in the next 15 years. It is necessary to educate on the adverse effects of tobacco consumption and to conduct vigilant oral self-examination among high-risk groups to help early detection and intervention at the same time.