PLA2G4A and ACHE modulate lipid profiles via glycerophospholipid metabolism in platinum-resistant gastric cancer.

BACKGROUND: Bioactive lipids involved in the progression of various diseases. Nevertheless, there is still a lack of biomarkers and relative regulatory targets. The lipidomic analysis of the samples from platinum-resistant in gastric cancer patients is expected to help us further improve our understanding of it. METHODS: We employed LC-MS based untargeted lipidomic analysis to search for potential candidate biomarkers for platinum resistance in GC patients. Partial least squares discriminant analysis (PLS-DA) and variable importance in projection (VIP) analysis were used to identify differential lipids. The possible molecular mechanisms and targets were obtained by metabolite set enrichment analysis and potential gene network screened. Finally, verified them by immunohistochemical of a tissue microarray. RESULTS: There were 71 differential lipid metabolites identified in GC samples between the chemotherapy-sensitivity group and the chemotherapy resistance group. According to Foldchange (FC) value, VIP value, P values (FC > 2, VIP > 1.5, p < 0.05), a total of 15 potential biomarkers were obtained, including MGDG(43:11)-H, Cer(d18:1/24:0) + HCOO, PI(18:0/18:1)-H, PE(16:1/18:1)-H, PE(36:2) + H, PE(34:2p)-H, Cer(d18:1 + hO/24:0) + HCOO, Cer(d18:1/23:0) + HCOO, PC(34:2e) + H, SM(d34:0) + H, LPC(18:2) + HCOO, PI(18:1/22:5)-H, PG(18:1/18:1)-H, Cer(d18:1/24:0) + H and PC(35:2) + H. Furthermore, we obtained five potential key targets (PLA2G4A, PLA2G3, DGKA, ACHE, and CHKA), and a metabolite-reaction-enzyme-gene interaction network was built to reveal the biological process of how they could disorder the endogenous lipid profile of platinum resistance in GC patients through the glycerophospholipid metabolism pathway. Finally, we further identified PLA2G4A and ACHE as core targets of the process by correlation analysis and tissue microarray immunohistochemical verification. CONCLUSION: PLA2G4A and ACHE regulated endogenous lipid profile in the platinum resistance in GC patients through the glycerophospholipid metabolism pathway. The screening of lipid biomarkers will facilitate earlier precision medicine interventions for chemotherapy-resistant gastric cancer. The development of therapies targeting PLA2G4A and ACHE could enhance platinum chemotherapy effectiveness.

Molecular SPECT/CT Profiling of Claudin18.2 Expression In Vivo: Implication for Patients with Gastric Cancer.

Zolbetuximab (IMAB362), a monoclonal antibody targeting Claudin18.2 (CLDN 18.2), demonstrates a significant clinical benefit in patients with advanced gastroesophageal cancers. The noninvasive assessment of CLDN18.2 expression through molecular imaging offers a potential avenue for expedited monitoring and the stratification of patients into risk groups. This study elucidates that CLDN18.2 is expressed at a noteworthy frequency in primary gastric cancers and their metastases. The iodogen method was employed to label IMAB362 with 123I/131I. The results demonstrated the efficient and reproducible synthesis of 123I-IMAB362, with a specific binding affinity to CLDN18.2. Immuno-single-photon emission computed tomography (SPECT) imaging revealed the rapid accumulation of 123I-IMAB362 in gastric cancer xenografts at 12 h, remaining stable for 3 days in patient-derived tumor xenograft models. Additionally, tracer uptake of 123I-IMAB362 in MKN45 cells surpassed that in MKN28 cells at each time point, with tumor uptake correlating significantly with CLDN18.2 expression levels. Positron emission tomography/computed tomography imaging indicated that tumor uptake of 18F-FDG and the functional/viable tumor volume in the 131I-IMAB362 group were significantly lower than those in the 123I-IMAB362 group on day 7. In conclusion, 123I-IMAB362 immuno-SPECT imaging offers an effective method for direct, noninvasive, and whole-body quantitative assessment of tumor CLDN18.2 expression in vivo. This approach holds promise for accelerating the monitoring and stratification of patients with gastric cancer.

Nobiletin targets SREBP1/ACLY to induce autophagy-dependent cell death of gastric cancer cells through PI3K/Akt/mTOR signaling pathway.

BACKGROUND: Autophagy could sense metabolic conditions and safeguard cells against nutrient deprivation, ultimately supporting the survival of cancer cells. Nobiletin (NOB) is a kind of bioactive component of the traditional Chinese medicine Citri Reticulatae Pericarpium and has been proven to induce GC cell death by reducing de novo fatty acid synthesis in our previous study. Nevertheless, the precise mechanisms by which NOB induces cell death in GC cells still need further elucidation. OBJECTIVES: To examine the mechanism by which NOB inhibits gastric cancer progression through the regulation of autophagy under the condition of lipid metabolism inhibition. METHODS/ STUDY DESIGN: Proliferation was detected by the CCK-8 assay. RNA sequencing (RNA-seq) was used to examine signaling pathway changes. Electron microscopy and mRFP-GFP-LC3 lentiviral transfection were performed to observe autophagy in vitro. Western blot, plasmid transfection, immunofluorescence staining, and CUT & Tag-qPCR techniques were utilized to explore the mechanisms by which NOB affects GC cells. Molecular docking and molecular dynamics simulations were conducted to predict the binding mode of NOB and SREBP1. CETSA was adopted to verify the predicted of binding model. A patient-derived xenograft (PDX) model was employed to verify the therapeutic efficacy of NOB in vivo. RESULTS: We conducted functional studies and discovered that NOB inhibited the protective effect of autophagy via the PI3K/Akt/mTOR axis in GC cells. Based on previous research, we found that the overexpression of ACLY abrogated the NOB-induced autophagy-dependent cell death. In silico analysis predicted the formation of a stable complex between NOB and SREBP1. In vitro assays confirmed that NOB treatment increased the thermal stability of SREBP1 at the same temperature conditions. Moreover, CUT&TAG-qPCR analysis revealed that NOB could inhibit SREBP1 binding to the ACLY promoter. In the PDX model, NOB suppressed tumor growth, causing SREBP1 nuclear translocation inhibition, PI3K/Akt/mTOR inactivation, and autophagy-dependent cell death. CONCLUSION: NOB demonstrated the ability to directly bind to SREBP1, inhibiting its nuclear translocation and binding to the ACLY promoter, thereby inducing autophagy-dependent cell death via PI3K/Akt/mTOR pathway.

Dehydrocostus lactone suppresses gastric cancer progression by targeting ACLY to inhibit fatty acid synthesis and autophagic flux.

INTRODUCTION: Dehydrocostus lactone (Dehy), a natural sesquiterpene lactone from Saussurea lappa Clarke, displays remarkable efficacy in treating cancer and gastrointestinal disorders. However, its anti-gastric cancer (GC) effect remains poorly understood. OBJECTIVES: Our study aimed to elucidate the anti-GC effect of Dehy and its putative mechanism. METHODS: The anti-GC effect was assessed with MTT, colony formation, wound healing and transwell invasion assays. Cell apoptosis rate was detected by Annexin V-FITC/PI binding assay. Network pharmacology analysis and XF substrate oxidation stress test explored the underlying mechanism and altered metabolic phenotype. Lipogenic enzyme expressions and neutral lipid pool were measured to evaluate cellular lipid synthesis and storage. Biolayer interferometry and molecular docking investigated the direct target of Dehy. Autophagosomes were observed by transmission electron microscopy and MDC staining, while the autophagic flux was detected by mRFP-GFP-LC3 transfection. The clinical significance of ACLY was confirmed by tissue microarrays. Patient-derived xenograft (PDX) models were adopted to detect the clinical therapeutic potential of Dehy. RESULTS: Dehy prominently suppressed GC progression both in vitro and in vivo. Mechanistically, Dehy down-regulated the lipogenic enzyme ACLY, thereby reducing fatty acid synthesis and lipid reservation. Moreover, IKKß was identified as the direct target of Dehy. Dehy inhibited the phosphorylation of IKKß, promoting the ubiquitination and degradation of ACLY, thereby resulting in lipid depletion. Subsequently, GC cells initiated autophagy to replenish the missing lipids, whereas Dehy impeded this cytoprotective mechanism by down-regulating LAMP1 and LAMP2 expressions, which disrupted lysosomal membrane functions, ultimately leading to apoptosis. Additionally, Dehy exhibited potential in GC clinical therapy as it enhanced the efficacy of 5-Fluorouracil in PDX models. CONCLUSIONS: Our work identified Dehy as a desirable agent for blunting abnormal lipid metabolism and highlighted its inhibitory effect on protective autophagy, suggesting the future development of Dehy as a novel therapeutic drug for GC.