Knockdown of Obg-like ATPase 1 enhances sorafenib sensitivity by inhibition of GSK-3β/β-catenin signaling in hepatocellular carcinoma cells

Conserved GTPase OLA1 promotes efficient translation on D/E-rich mRNA

The TRAFAC (translation factors) GTPase OLA1 plays a critical role in various stress responses and is implicated in the regulation of tumor progression. It is conserved from bacteria to eukaryotes and regulates the translation through binding to the ribosome. Here, we report the cryo-electron microscopy structure of its Escherichia coli homolog, YchF, with the 50S subunit. In this structure, YchF is positioned at the side of the 50S subunit by engaging with uL14, bL19, and rRNA helix H62 through its helical and ATPase domains. We further demonstrate that the helical domain is essential for OLA1/YchF to function. A comprehensive analysis of the structure and Ribo-seq data points out that OLA1/YchF promotes the splitting of ribosomes into subunits on D/E-rich mRNA. Our findings provide crucial structural insights into the molecular mechanism of OLA1/YchF-associated translation-stalling regulation, which maintains the translation of genes involved in stress response and tumor progression.

A mechanistic study of Anwei decoction intervention in a rat model of gastric intestinal metaplasia through the endoplasmic reticulum stress - Autophagy pathway

OBJECTIVE

To investigate the mechanism of Anwei decoction (AWD) intervention on gastric intestinal metaplasia (GIM) using a rat model through the endoplasmic reticulum stress-autophagy pathway.

METHODS

Gastric intestinal metaplasia was induced in rats using 1-methyl-3-nitro-1-nitrosoguanidine. The experiment included a normal control group, a model group, and low-, medium- and high-dose AWD groups. The specificity of intestinal epithelial cells was determined for model establishment and drug efficacy by detecting the protein expression of markers such as MUC2, VILLIN and CDX2 through western blotting (WB). The effects of AWD on endoplasmic reticulum stress and autophagy were evaluated by measuring the mRNA and protein expression levels of endoplasmic reticulum stress markers (PEPK, ATF6, CHOP and caspase-12) and autophagy markers (LC3Ⅱ and Beclin-1) using reverse transcription polymerase chain reaction and the WB method. Furthermore, the ultrastructure of gastric mucosal cells and autophagosome status were observed using transmission electron microscopy.

RESULTS

Compared with the model group, the AWD-treated rats exhibited significant improvement in body weight (P < 0.01), reduced protein expression of the intestine epithelial cell-specific markers MUC2, VILLIN, CDX2 and KLF4 (P < 0.01 for all) and increased SOX2 protein expression (P < 0.01). In addition, AWD suppressed the mRNA and protein expression of endoplasmic reticulum stress markers PEPK and ATF6 (P < 0.01 for all) and promoted the mRNA and protein expression of autophagy and apoptosis markers CHOP, caspase-12, LC3Ⅱ and Beclin-1 (P < 0.01 for all).

CONCLUSION

Anwei decoction effectively inhibits the further progression of GIM and prevents the occurrence of gastric mucosal carcinogenesis.