Helicobacter pylori promotes gastric cancer through CagA-mediated mitochondrial cholesterol accumulation by targeting CYP11A1 redistribution.

Cholesterol and Helicobacter pylori (H. pylori) are both risk factors for gastric cancer (GC). However, the relationship between cholesterol and H. pylori and their function in the progression of GC are controversial. In this study, we addressed that H. pylori could induce mitochondrial cholesterol accumulation and promote GC proliferation and protect GC cells against apoptosis via cholesterol. Metabolomic and transcriptomic sequencing were used to identify CYP11A1 responsible for H. pylori-induced cholesterol accumulation. In vitro and in vivo function experiments revealed that cholesterol could promote the proliferation of GC and inhibit apoptosis. Mechanically, the interaction of Cytotoxin-associated gene A (CagA) and CYP11A1 redistributed mitochondrial CYP11A1 outside the mitochondria and subsequently caused mitochondrial cholesterol accumulation. The CYP11A1-knockdown upregulated cholesterol accumulation and reproduced the effect of cholesterol on GC in a cholesterol-dependent manner. Moreover, CYP11A1-knockdown or H. pylori infection inhibited mitophagy and maintained the mitochondria homeostasis. H. pylori could contribute to the progression of GC through the CagA/CYP11A1-mitoCHO axis. This study demonstrates that H. pylori can contribute to the progression of GC via cholesterol, and eradicating H. pylori is still prognostically beneficial to GC patients.

Comparison of Short-term and Long-term Outcomes after Different Reconstructions between Totally Laparoscopic Distal Gastrectomy and Laparoscopic-assisted Distal Gastrectomy for Gastric Cancer: a Retrospective Analysis at a High-volume Center.

Background: The short-term and long-term outcomes of laparoscopic-assisted distal gastrectomy (LADG) and totally laparoscopic distal gastrectomy (TLDG) have been subject to controversy with various reconstruction techniques of Billroth-I, Billroth-II, Roux-en-Y, and Uncut. This study aims to compare the short-term and long-term outcomes of LADG and TLDG as well as the outcomes of different anastomoses. Methods: This study enrolled patients with gastric cancer at the First Affiliated Hospital of Nanjing Medical University (NMUH) between 2017 and 2021. Postoperative complications were classified according to the Clavien-Dindo grade. Exclusion criteria included metachronous and synchronous malignancy and palliative surgery. The Kaplan-Meier analysis was applied to assess 5-year prognosis between two groups. Results: This study included 1221 cases with an overall complication rate of 17.37% for LADG, which was significantly higher than TLDG's 10.72%. The incidence of anastomosis-related complications was 4.79% for LADG and 1.13% lower for TLDG. LADG and TLDG did not show significant difference for Grade III-V complications and resected lymph nodes. The postoperative stay was shorter for TLDG than LADG, and R-Y had a longer postoperative stay than B-II and Uncut after combining LADG and TLDG. The operation time was shorter in TLDG cases than that in LADG cases. The 5-year OS of the TLDG group was not significantly better than that of the LADG group. Conclusion: TLDG is superior in overall complication rate, anastomosis-related complication rate, postoperative stay and operation time to LADG. No difference of OS was observed between LADG and TLDG. Four anastomoses had no convincing evidence of being superior in complications rates, post-op stay, and harvested lymph nodes to each other.

Cross-talk of Three Molecular Subtypes of Telomere Maintenance Defines Clinical Characteristics and Tumor Microenvironment in Gastric Cancer.

Background: Telomere maintenance takes part in the regulation of gastric cancer (GC) pathogenesis and is essential for patients' clinical features. Though the correlation between a single telomere maintenance-related gene and GC has previously been published, comprehensive exploration and systematic analysis remain to be studied. Our study is aimed at determining telomere maintenance-related molecular subtypes and examining their role in GC. Methods: By analyzing the transcriptome data, we identified three telomere maintenance-associated clusters (TMCs) with heterogeneity in clinical features and tumor microenvironment (TME). Then, we screened five prognostic telomere maintenance-related genes and established corresponding TM scores. Additionally, the expression level and biological function of tubulin beta 6 class V (TUBB6) were validated in GC tissues and cells. Results: TMC1 was correlated with EMT and TGF-beta pathway and predicted low tumor mutation burden (TMB) as well as bad prognostic outcomes. TMC3 was associated with cell cycle and DNA repair. In terms of TMB and overall survival, TMC3 exhibited opposite results against TMC1. Significant heterogeneity was observed between TMCs. TUBB6 was upregulated and could promote GC proliferation, migration, and invasion. Conclusion: Altogether, combining bioinformatics and functional experiments, we identified three molecular subtypes based on telomere maintenance-associated genes in GC, which could bring new ideas and novel biomarkers to the clinic.