Post-transcriptional dynamics and RNA homeostasis in autophagy and cancer

N6-methyladenosine (m6A) reader HNRNPA2B1 accelerates the cervical cancer cells aerobic glycolysis

N6-methyladenosine (m6A) modification is, a more common epigenetic modification, mainly found in mRNA. More and more researches have shown the important functions of m6A on human cancers. This study seeks to explore the role of hnRNPA2B1 and m6A-dependent mechanism in cervical cancer. Elevated hnRNPA2B1 indicated the poor prognosis of cervical cancer patients. Enforced hnRNPA2B1 reduced the apoptosis, and accelerated the proliferation and migration of cervical cancer cells in vitro. Besides, hnRNPA2B1 promoted the aerobic glycolysis of cervical cancer cells, including the lactate secretion, glucose uptake, ATP production, extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). LDHA was found as the downstream target of hnRNPA2B1 by m6A site. Moreover, hnRNPA2B1 enhanced the mRNA stability of LDHA through m6A-dependent manner. LDHA inhibitor (FX-11) could reverse the effect of hnRNPA2B1. Taken together, the data revealed that hnRNPA2B1 promoted the proliferation, migration and aerobic glycolysis of cervical cancer cells by m6A/LDHA-dependent manner. These findings might bring a new idea for cervical cancer treatment.

Estrogen receptor-related receptor (Esrra) induces ribosomal protein Rplp1-mediated adaptive hepatic translation during prolonged starvation

Protein translation is an energy-intensive ribosome-driven process that is reduced during nutrient scarcity to conserve cellular resources. During prolonged starvation, cells selectively translate specific proteins to enhance their survival (adaptive translation); however, this process is poorly understood. Accordingly, we analyzed protein translation and mRNA transcription by multiple methods in vitro and in vivo to investigate adaptive hepatic translation during starvation. While acute starvation suppressed protein translation in general, proteomic analysis showed that prolonged starvation selectively induced translation of lysosome and autolysosome proteins. Significantly, the expression of the orphan nuclear receptor, estrogen-related receptor alpha (Esrra) increased during prolonged starvation and served as a master regulator of this adaptive translation by transcriptionally stimulating 60S acidic ribosomal protein P1 (Rplp1) gene expression. Overexpression or siRNA knockdown of Esrra expression in vitro or in vivo led to parallel changes in Rplp1 gene expression, lysosome/autophagy protein translation, and autophagy. Remarkably, we have found that Esrra had dual functions by not only regulating transcription but also controling adaptive translation via the Esrra/Rplp1/lysosome/autophagy pathway during prolonged starvation.