ALKBH5 regulates STAT3 activity to affect the proliferation and tumorigenicity of osteosarcoma via an m6A-YTHDF2-dependent manner.
N6-methyladenosine (m6A) is the most common and abundant mRNA modification and it plays crucial roles in many biological processes. However, as a key RNA demethylase, alkylation repair homolog protein 5 (ALKBH5) has not been well studied in human osteosarcoma. The present study sought to explore ALKBH5-mediated m6A modification and the underlying mechanisms in human osteosarcoma.
The expression of ALKBH5 and its correlation with clinicopathological features were examined by bioinformatics analysis and tissue microarrays. Cellular proliferation was detected by CCK8 assays. Cell cycle and apoptosis were analyzed by TUNEL and Flow cytometry assay. Finally, investigation of the regulatory mechanism of ALKBH5 in human osteosarcoma was performed by MeRIP assay, RNA-sequencing, dual luciferase reporter assay, RNA pull-down and RNA stability assay. Tumor xenograft models were established for in vivo experiments.
Our data showed that low expression of ALKBH5 was associated with worse overall survival for osteosarcoma patients. Reducing m6A mRNA levels in human osteosarcoma cells through ALKBH5 up-regulation lead to cell proliferation inhibition, cell apoptosis and cycle arrest. We identified SOCS3, a negative regulator of STAT3, as a downstream target of ALKBH5-mediated m6A modification. And the m6A modified SOCS3 mRNA was recognized by YTHDF2, which promotes the decay of SOCS3. Mechanistically, our data revealed that ALKBH5 inactivated STAT3 pathway by increasing SOCS3 expression via an m6A-YTHDF2-dependent manner.
M6A methylation is rising as a pathway affecting tumorigenicity and tumor progression. Our findings illuminate the clinical significance of ALKBH5-mediated m6A modification in human osteosarcoma and the regulatory mechanisms underlying tumor proliferation and growth, suggesting that ALKBH5 is a potential biomarker for treatment in human osteosarcoma.
This work was supported by and Science and Technology foundation of Hubei, China (Grant No.2017CFB762); the Tongji hospital foundation (Grant No.2201103013); and the National Natural Science Foudation of China (No.82002849).
Yang Z
，Cai Z
，Yang C
，Luo Z
，Bao X
... -
《EBioMedicine》
RNA demethylase ALKBH5 promotes colorectal cancer progression by posttranscriptional activation of RAB5A in an m6A-YTHDF2-dependent manner.
N6-methyladenosine (m6A) modification is an emerging epigenetic regulatory mechanism in tumourigenesis. Considering that AlkB homolog 5 (ALKBH5) is a well-described m6A demethylase in previous enzyme assays, we aimed to investigate the role of m6A methylation alteration conferred by disturbed ALKBH5 in colorectal cancer (CRC) development.
Expression of ALKBH5 and its correlation with clinicopathological characteristics of CRC were evaluated using the prospectively maintained institutional database. The molecular role and underlying mechanism of ALKBH5 in CRC were explored using in vitro and in vivo experiments with methylated RNA immunoprecipitation sequencing (MeRIP-seq), RNA-seq, MeRIP-qPCR, RIP-qPCR and luciferase reporter assays.
ALKBH5 expression was significantly upregulated in CRC tissues compared to the paired adjacent normal tissues, and higher expression of ALKBH5 was independently associated with worse overall survival in CRC patients. Functionally, ALKBH5 promoted the proliferative, migrative and invasive abilities of CRC cells in vitro and enhanced subcutaneous tumour growth in vivo. Mechanistically, RAB5A was identified as the downstream target of ALKBH5 in CRC development, and ALKBH5 posttranscriptionally activated RAB5A by m6A demethylation, which impeded the YTHDF2-mediated degradation of RAB5A mRNA. In addition, we demonstrated that dysregulation of the ALKBH5-RAB5A axis could affect the tumourigenicity of CRC.
ALKBH5 facilitates the progression of CRC by augmenting the expression of RAB5A via an m6A-YTHDF2-dependent manner. Our findings suggested that ALKBH5-RAB5A axis might serve as valuable biomarkers and effective therapeutic targets for CRC.
Shen D
，Lin J
，Xie Y
，Zhuang Z
，Xu G
，Peng S
，Tang G
，Bai L
，Zhu M
，Zhang Y
，Huang Z
，Wang P
，Liu X
，Huang M
，Luo Y
，Wang X
，Yu H
... -
《Clinical and Translational Medicine》
Decreased ALKBH5, FTO, and YTHDF2 in Peripheral Blood Are as Risk Factors for Rheumatoid Arthritis.
ALKBH5 (alkylation repair homolog protein 5), FTO (fat mass and obesity-associated protein), and RNA N6-methyladenosine (m6A) demethylase, are essential for the m6A mRNA modification. YTHDF2 (YT521-B homology domains 2) called m6A "readers" can recognize m6A modification. As the key enzymes of m6A methylation modification, ALKBH5, FTO, and YTHDF2 have been implicated in many diseases. However, little is known about the role of ALKBH5, FTO, and YTHDF2 in rheumatoid arthritis (RA). We measured the mRNA expression of ALKBH5, FTO, and YTHDF2 in RA patients and controls by quantitative real-time polymerase chain reaction, and the global m6A content was detected by an ELISA-like format. The mRNA expression of ALKBH5, FTO, and YTHDF2 in RA patients was further analyzed to investigate its correlations with disease activity. And, multivariate analysis (logistic regression) was used to analyze the risk factors. The mRNA expression of ALKBH5, FTO, and YTHDF2 in RA patients was significantly decreased compared to controls. The mRNA expression of ALKBH5 was significantly increased in RA patients that received regular treatment. The mRNA expression of FTO was associated with disease activity score 28 (DAS28), complement 3 (C3), immunoglobulin G (IgG), and lymphocyte-to-monocyte ratio (LMR), some common markers for RA disease activity. The mRNA expression of YTHDF2 was associated with RBC, L%, N%, NLR, and LMR. Furthermore, logistic regression analysis revealed that decreased expression of ALKBH5, FTO, and YTHDF2 in peripheral blood was a risk factor for RA. Moreover, the peripheral blood global m6A content was significantly increased in patients with RA compared to CON, and increased m6A contents negatively correlated with decreased mRNA expression of FTO. In conclusion, this study firstly demonstrates the critical role of ALKBH5, FTO, and YTHDF2 in RA, which provides novel insights into recognizing the pathogenesis of RA and a promising biomarker for RA.
Luo Q
，Gao Y
，Zhang L
，Rao J
，Guo Y
，Huang Z
，Li J
... -
《-》
ResearchGate
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