Changes of N6-methyladenosine modulators promote breast cancer progression.
BACKGROUND
Breast cancer (BC) displays striking genetic, epigenetic and phenotypic diversity. N6-methyladenosine (m6A) in mRNA has emerged as a crucial epitranscriptomic modification that controls cancer self-renewal and cell fate. However, the key enzymes of m6A expression and function in human breast carcinogenesis remain unclear.


METHODS
The expression of m6A methylases (METTL3, METTL14 and WTAP) and demethylases (FTO and ALKBH5) were analyzed by using ONCOMINE and The Cancer Genome Atlas databases and in 36 pairs of BC and adjacent non-cancerous tissue. The level of m6A in BC patients was detected by ELISA, and the function of m6A was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay and transwell assay. The database of bc-GenExMiner v4.0, Kaplan-Meier Plotter and cBioPortal were queried for correlation, mutation and prognosis analysis of BC.


RESULTS
The m6A methylases and demethylases were dysregulated in several major malignant tumors. Specifically, the expression of all m6A methylases was reduced in BC as compared with normal controls, but the demethylase ALKBH5 was induced in ONCOMINE databases and confirmed in clinical patients. METTL14 expression was positively correlated with METTL3 expression, and both showed high expression in normal breast-like and luminal-A and -B BC. Functionally, reducing m6A expression by overexpressing METTL14 and/or knockdown of ALKBH5 could inhibit breast cell viability, colony formation and cell migration. Furthermore, Kaplan-Meier, meta-analysis and univariate Cox assay showed that the expression of m6A members including METTL3, METTL14, WTAP and FTO but not their gene mutation and amplification, was tightly associated with cancer progression and poor survival.


CONCLUSIONS
Changes of m6A modulators reduced m6A may promote tumorigenesis and predict poor prognosis in BC.
['Wu|Lianpin|L|', 'Wu|Dengying|D|', 'Ning|Jinfeng|J|', 'Liu|Wei|W|', 'Zhang|Donghong|D|']
D000241:Adenosine D000328:Adult D001940:Breast D001943:Breast Neoplasms D063646:Carcinogenesis D045744:Cell Line, Tumor D066264:Datasets as Topic D018450:Disease Progression D044127:Epigenesis, Genetic D005260:Female D020869:Gene Expression Profiling D015972:Gene Expression Regulation, Neoplastic D006801:Humans D053208:Kaplan-Meier Estimate D008745:Methylation D008780:Methyltransferases D008875:Middle Aged D009154:Mutation D010089:Oxidoreductases, N-Demethylating D011379:Prognosis D012333:RNA, Messenger
N6-methyladenosine Breast cancer Prognosis Migration transcription