Purpose: Glucose starvation induces the accumulation of disulfides and F-actin collapse in cells with high expression of SLC7A11, a phenomenon termed disulfidptosis. This study aimed to confirm the existence of disulfidptosis in pancreatic ductal adenocarcinoma (PDAC) and elucidate the role of Cancer Susceptibility 8 (CASC8) in this process. Methods: The existence of disulfidptosis in PDAC was assessed using flow cytometry and F-actin staining. CASC8 expression and its clinical correlations were analyzed using data from The Cancer Genome Atlas (TCGA) and further verified by chromogenic in situ hybridization assay in PDAC tissues. Cells with CASC8 knockdown and overexpression were subjected to cell viability, EdU, transwell assays, and used to establish subcutaneous and orthotopic tumor models. Disulfidptosis was detected by flow cytometry and immunofluorescence assays. RNA sequencing and metabolomics analysis were performed to determine the metabolic pathways which were significantly affected after CASC8 knockdown. We detected the glucose consumption and the NADP⁺/NADPH ratio to investigate alterations in metabolic profiles. RNA immunoprecipitation combined with fluorescence in situ hybridization assay was used to identify protein-RNA interactions. Protein stability, western blotting and quantitative real-time PCR assays were performed to reveal potential molecular mechanism. Results: Disulfidptosis was observed in PDAC and could be significantly rescued by disulfidptosis inhibitors. CASC8 expression was higher in PDAC samples compared to normal pancreatic tissue. High CASC8 expression correlated with a poor prognosis for patients with PDAC and contributed to cancer progression in vitro and in vivo. Furthermore, CASC8 was associated with disulfidptosis resistance under glucose starvation conditions in PDAC. Mechanistically, CASC8 interacted with c-Myc to enhance the stability of c-Myc protein, leading to the activation of the pentose phosphate pathway, a reduction of the NADP⁺/NADPH ratio and ultimately inhibiting disulfidptosis under glucose starvation conditions. Conclusions: This study provides evidence for the existence of disulfidptosis in PDAC and reveals the upregulation of CASC8 in this malignancy. Furthermore, we demonstrate that CASC8 acts as a crucial regulator of the pentose phosphate pathway and disulfidptosis, thereby promoting PDAC progression.

Adipocyte infiltration in pancreatic cancer (PC) has been demonstrated to be independently associated with PC risk and an active contributor to tumor progression. However, to date, little is known about these unique pancreatic tumor‑surrounding adipocytes, or their response to cancer cells. The present study utilized an in vitro indirect coculture model in which the phenotypic changes of adipocytes following exposure to PC cells were directly observed. RNA‑sequencing was performed on 3T3‑L1 adipocytes cultured with or without Panc‑1 cancer cells, and significant changes were identified at the transcriptional level. In terms of delipidation and the impaired function of glucose and lipid metabolism, coculture with tumor cells resulted in an altered metabolic phenotype in mature adipocytes. In co‑cultured adipocytes, the appearance of fibroblast‑like cells was observed, and the mesenchymal cell differentiation pathway was enriched following the integrated analysis into the transcriptome. In addition, reverse transcription‑quantitative PCR analyses of co‑cultured adipocytes revealed a loss in gene expression of mature adipocyte markers, and a gain in gene expression of fibroblast‑specific markers. It was also confirmed that newly generated cancer‑associated adipocytes could facilitate the invasive capacities of the tumor, and may contribute to PC stromal remodeling. The present study supports a novel concept that reprogramming of stromal adipocytes orchestrated by PC cells may generate cancer‑associated adipocytes with activated phenotypes, which may ultimately drive pancreatic tumor progression.

Locally advanced and metastatic pancreatic cancer (PC) frequently grows in adipose tissue and has a poor prognosis. Although adipose tissue is largely composed of adipocytes, the mechanisms by which adipocytes impact PC are poorly understood. Using an in vitro coculture model, it was shown that adipocytes promoted tumor progression, and an intricate metabolic network between PC cells and adipocytes was identified and elucidated. First, the proteome of Panc‑1 PC cells cultured with or without mature adipocytes was identified. This revealed activated hypoxia signaling in cocultured Panc‑1 cells, which was confirmed by the increased expression of factors downstream of hypoxia signaling, such as ANGPTL4 and glycolytic genes, as determined by reverse transcription‑quantitative PCR and western blot analysis. In addition, it was demonstrated that coculture with cancer cells activated STAT3 and induced an insulin‑resistant phenotype in adipocytes. Furthermore, enhanced fatty acid β‑oxidation and increased lipid droplets (LDs) were observed in the cocultured cancer cells. In contrast, downregulated lipid metabolism and a decrease in the size of LDs were found in cocultured adipocytes. Finally, it was shown that the increase in LDs contributed to the increased metastatic capacity of the cocultured PC cells. These data demonstrated that interrupting the mechanisms of lipid uptake from adipocytes in the microenvironment may offer a potential strategy for attenuating PC metastasis.

BACKGROUND The TRIANGLE operation involves the removal of all tissues within the triangle bounded by the portal vein-superior mesenteric vein, celiac axis-common hepatic artery, and superior mesenteric artery to improve patient prognosis. Although previously promising in patients with locally advanced pancreatic ductal adenocarcinoma (PDAC), data are limited regarding the long-term oncological outcomes of the TRIANGLE operation among resectable PDAC patients undergoing pancreaticoduodenectomy (PD). AIM To evaluate the safety of the TRIANGLE operation during PD and the prognosis in patients with resectable PDAC. METHODS This retrospective cohort study included patients who underwent PD for pancreatic head cancer between January 2017 and April 2023, with or without the TRIANGLE operation. Patients were divided into the PDTRIANGLE and PDnon-TRIANGLE groups. Surgical and survival outcomes were compared between the two groups. Adequate adjuvant chemotherapy was defined as adjuvant chemotherapy ≥ 6 months. RESULTS The PDTRIANGLE and PDnon-TRIANGLE groups included 52 and 55 patients, respectively. There were no significant differences in the baseline characteristics or perioperative indexes between the two groups. Furthermore, the recurrence rate was lower in the PDTRIANGLE group than in the PDnon-TRIANGLE group (48.1% vs 81.8%, P < 0.001), and the local recurrence rate of PDAC decreased from 37.8% to 16.0%. Multivariate Cox regression analysis revealed that PDTRIANGLE (HR = 0.424; 95%CI: 0.256-0.702; P = 0.001), adequate adjuvant chemotherapy ≥ 6 months (HR = 0.370; 95%CI: 0.222-0.618; P < 0.001) and margin status (HR = 2.255; 95%CI: 1.252-4.064; P = 0.007) were found to be independent factors for the recurrence rate. CONCLUSION The TRIANGLE operation is safe for PDAC patients undergoing PD. Moreover, it reduces the local recurrence rate of PDAC and may improve survival in patients who receive adequate adjuvant chemotherapy.

Low preoperative skeletal muscle index increases the risk of mortality among resectable pancreatic cancer patients: A retrospective study