Methyltransferase-like 3 facilitates lung cancer progression by accelerating m6A methylation-mediated primary miR-663 processing and impeding SOCS6 expression

• Published in: Journal of cancer research and clinical oncology Vol. 148; no. 12; pp. 3485 - 3499
• Main Authors: Li, Shengshu, Lu, Xiaoxin, Zheng, Dongyang, Chen, Weizong, Li, Yuzhu, Li, Fang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2022; Springer Nature B.V
• Subjects: Animals; Apoptosis; Binding sites; Cancer Research; Carcinogenesis; Cell growth; Cell migration; Cell proliferation; Cell viability; Cholecystokinin; Flow cytometry; Hematology; Humans; Immunoprecipitation; Internal Medicine; Lung cancer; Lung Neoplasms - genetics; Medicine; Medicine & Public Health; Methylation; Methyltransferase; Methyltransferases - genetics; Methyltransferases - metabolism; Mice; Mice, Nude; MicroRNAs - genetics; MicroRNAs - metabolism; miRNA; N6-methyladenosine; Oncology; Original Article – Cancer Research; RNA-Binding Proteins - metabolism; Sincalide - metabolism; Suppressor of Cytokine Signaling Proteins - genetics; Suppressor of Cytokine Signaling Proteins - metabolism; Tumors; Xenografts; m6A methylation; Primary miR-663; Methyltransferase-like 3; Lung cancer; Tumor formation assay; Migration and invasion; SOCS6
• ISSN: 0171-5216; 1432-1335
• DOI: 10.1007/s00432-022-04128-5

Objective
Lung cancer (LC) remains a threatening health issue worldwide. Methyltransferase-like protein 3 (METTL3) is imperative in carcinogenesis via m6A modification of microRNAs (miRNAs). This study estimated the effect of METTL3 in LC by regulating m6A methylation-mediated pri-miR-663 processing.
Methods
miR-663 expression in 4 LC cell lines and normal HBE cells was determined using RT-qPCR. A549 and PC9 LC cells selected for in vitro studies were transfected with miR-663 mimics or inhibitor. Cell viability, migration, invasion, proliferation, and apoptosis were detected by CCK-8, Transwell, EdU, and flow cytometry assays. The downstream target genes and binding sites of miR-663 were predicted via Starbase database and validated by dual-luciferase assay. LC cells were delivered with oe-METTL3/sh-METTL3. Crosslinking between METTL3 and DGCR8 was verified by co-immunoprecipitation. Levels of m6A, miR-663, and pri-miR-663 were measured by m6A dot blot assay and RT-qPCR. m6A modification of pri-miR-663 was verified by Me-RIP assay. Finally, the effects of METTL3 in vivo were ascertained by tumor xenograft in nude mice.
Results
miR-663 was upregulated in LC cells, and miR-663 overexpression promoted cell proliferation, migration, invasion, and inhibited apoptosis, but miR-663 knockdown exerted the opposite effects. miR-663 repressed SOCS6 expression. SOCS6 overexpression annulled the promotion of miR-663 on LC cell growth. METTL3 bound to DGCR8, and METTL3 silencing elevated the levels of pri-miR-663 and m6A methylation-modified pri-miR-663, and suppressed miR-663 maturation and miR-663 expression. METTL3 facilitated tumor growth in mice through the miR-663/SOCS6 axis.
Conclusion
METTL3 promotes LC progression by accelerating m6A methylation-mediated pri-miR-663 processing and repressing SOCS6.