Vitamin D and Gastric Cancer: A Ray of Sunshine?

Common variants of vitamin D receptor gene polymorphisms and risk of gastric cancer: A meta-analysis

BACKGROUND

While earlier studies have suggested that variations in the vitamin D receptor (VDR) gene could influence the susceptibility to gastric cancer (GC), the results have shown inconsistency. This meta-analysis aimed to examine the association of 5 common polymorphisms in VDR, including Taq1 rs731236 (T > C), FokI rs2228570 (C > T), Cdx2 rs11568820 (G > A), BsmI rs1544410 (G > A), and ApaI rs7975232 (G > T) with the risk of GC.

METHODS

A comprehensive search was carried out in PubMed, Web of Science, and Scopus to identify relevant studies published until January 2024. Odds ratios (ORs) with 95% confidence intervals (CIs) were utilized to assess the magnitude of associations.

RESULTS

Nine studies, with 2837 participants (1215 GC cases and 1622 healthy controls), were eligible. The FokI rs2228570 polymorphism showed a significant correlation with heightened susceptibility to GC under the recessive model (OR = 1.52; 95% CI: 1.06-2.19) and homozygote comparison (TT vs CC; OR = 1.59; 95% CI: 1.09-2.31). Taq1 rs731236 was also linked to an elevated risk of GC under the same models (recessive OR = 1.65; 95% CI: 1.14-2.39; homozygote OR = 1.68; 95% CI: 1.11-2.54). In the sensitivity analysis, when studies not adhering to Hardy-Weinberg equilibrium were excluded, the relationship between FokI rs2228570 polymorphism and GC disappeared, while the association for Taq1 rs731236 remained consistent. No significant association was identified for BsmI rs1544410, ApaI rs7975232, and Cdx2 rs11568820.

CONCLUSION

This study revealed that FokI rs2228570 and Taq1 rs731236 polymorphisms of VDR might be linked to the odds of GC.

Vitamin D3 promotes gastric cancer cell autophagy by mediating p53/AMPK/mTOR signaling

Objective: Vitamin D3 has the general properties of a lipid-soluble vitamin, but is also an active steroid hormone that can regulate the proliferation, apoptosis and differentiation of many tumor cells, and exerts anticancer activity against numerous malignancies. However, the mechanism underlying the effects of vitamin D3 on tumors is not fully understood. Here, we used network pharmacology and in vitro experimental approaches to explore the mechanism of vitamin D3 activity in the context of gastric cancer. Methods: The Targetnet, SuperPred, SwissTargetPrediction, and PharmMapper databases were screened for potential drug-related targets, while we used data from the PharmGKB, Drugbank, OMIM, DisGeNET, CTD, and GeneCards databases to identify potential targets associated with gastric cancer. Disease-drug crossover genes were obtained by constructing Venn diagrams. Gene ontology and Kyoto Encyclopedia of Genomes (KEGG) enrichment analyses of crossover genes were conducted and STRING was used to generate protein interaction networks and identify core targets. CCK-8 experiments were performed and apoptosis detected to assess the effect of vitamin D3 on gastric cancer cells. Western blotting was applied to detect p53/AMPK/mTOR signaling, as well as autophagy-, cell cycle-, and apoptosis-related proteins. Results: A total of 485 targets of vitamin D3 activity were obtained and 1200 gastric cancer disease-related targets discovered. Further, 60 potential targets for vitamin D3 in gastric cancer treatment were identified. KEGG analysis indicated that potential targets were mainly involved in the cell cycle, HIF-1 signaling, and the AMPK pathway, among other pathways. These findings were validated using cellular experiments, which demonstrated that the viability of AGS and SGC-7901 cells was impeded by vitamin D3. Further, vitamin D3 promoted apoptosis and inhibited the cell cycle in those cell lines, as well as activating the p53/AMPK/mTOR pathway, which promotes autophagy and inhibits tumor development. Conclusion: Our network pharmacological analyses provide preliminarily data supporting a role for vitamin D3 in promoting autophagy and apoptosis in gastric cancer cells, and in activating the p53/AMPK/mTOR pathway, which inhibits gastric cancer cell proliferation. Our findings demonstrate the molecular mechanism underlying the effect of vitamin D3 in cure of gastric cancer.

Vitamin D—The Nutritional Status of Post-Gastrectomy Gastric Cancer Patients—Systematic Review

Gastric cancer is a malignant neoplasm of the gastrointestinal tract, with one of the standard treatment methods remaining gastrectomy. The authors conducted a systemic review of the Medline and Embase databases concerning the serum vitamin D level in post-gastrectomy gastric cancer patients, regarding all articles published until 22 May 2022 according to the PRISMA guidelines. 18 studies with a total number of 908 gastric cancer survivors were included in the analysis. The initial rate of vitamin D deficiency in gastric cancer patients undergoing gastrectomy appears to be similar to the global population deficiency. In post-gastrectomy survivors, the level of 25(OH)D may remain stable or decrease, while the level of 1, 25(OH)₂D remains normal. Supplementation with vitamin D results in an improvement in its serum concentration and positively affects bone mineral density, which is gradually reduced in post-gastrectomy survivors. Combining vitamin D supplementation with calcium and bisphosphonates enables us to obtain better results than vitamin D and calcium only. The type of surgery influences the level of serum vitamin D and its metabolites, with total or partial gastrectomy and maintenance of the duodenal food passage remaining the most important factors. There is a strong need for randomized, controlled trials that would investigate this matter in the future.