N6-methyladenosine reader IMP2 stabilizes the ZFAS1/OLA1 axis and activates the Warburg effect: implication in colorectal cancer

Abstract

Background

Accumulating evidence shows that N6-methyladenine (m ⁶A) modulators contribute to the etiology and progression of colorectal cancer (CRC). However, the exact mechanisms of m ⁶A reader involved in glycolytic metabolism remain vague. This article aimed to crosstalk the m ⁶A reader with glycolytic metabolism and reveal a new mechanism for the progression of CRC.

Methods

The relationship between candidate lncRNA and m ⁶A reader was analyzed by bioinformatics, ISH and IHC assays. In vivo and in vitro studies (including MTT, CFA, trans-well, apoptosis, western blot, qRT-PCR and xenograft mouse models) were utilized to explore the biological functions of these indicators. Lactate detection, ATP activity detection and ECAR assays were used to verify the biological function of the downstream target. The bioinformatics, RNA stability, RIP experiments and RNA pull-down assays were used to explore the potential molecular mechanisms.

Results

We identified that the crosstalk of the m ⁶A reader IMP2 with long-noncoding RNA (lncRNA) ZFAS1 in an m ⁶A modulation-dependent manner, subsequently augmented the recruitment of Obg-like ATPase 1 (OLA1) and adenosine triphosphate (ATP) hydrolysis and glycolysis during CRC proliferation and progression. Specifically, IMP2 and ZFAS1 are significantly overexpressed with elevated m ⁶A levels in CRC cells and paired CRC cohorts ( n = 144). These indicators could be independent biomarkers for CRC prognostic prediction. Notably, IMP2 regulated ZFAS1 expression and enhanced CRC cell proliferation, colony formation, and apoptosis inhibition; thus, it was oncogenic. Mechanistically, ZFAS1 is modified at adenosine +843 within the RGGAC/RRACH element in an m ⁶A-dependent manner. Thus, direct interaction between the KH3–4 domain of IMP2 and ZFAS1 where IMP2 serves as a reader for m ⁶A-modified ZFAS1 and promotes the RNA stability of ZFAS1 is critical for CRC development. More importantly, stabilized ZFAS1 recognizes the OBG-type functional domain of OLA1, which facilitated the exposure of ATP-binding sites (NVGKST, 32–37), enhanced its protein activity, and ultimately accelerated ATP hydrolysis and the Warburg effect.

Conclusions

Our findings reveal a new cancer-promoting mechanism, that is, the critical modulation network underlying m ⁶A readers stabilizes lncRNAs, and they jointly promote mitochondrial energy metabolism in the pathogenesis of CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01204-0.