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Nasopharyngeal carcinoma (NPC) is endemic in Southern China and Southeast Asia. Hyperthermia is widely used in combination with chemotherapy and radiotherapy to enhance therapeutic efficacy in NPC treatment, but the underlying anti-tumor mechanisms of hyperthermia remain unclear. Complement C3 has been reported to participate in the activation of immune system in the tumor microenvironment, leading to tumor growth inhibition. In this study, we aimed to explore the effect and mechanisms of hyperthermia and investigate the functional role of complement C3 in NPC hyperthermia therapy (HT). The serum levels of complement C3 before and after hyperthermia therapy in patients with NPC were analyzed. NPC cell lines SUNE1 and HONE1 were used for in vitro experiment to evaluate the function of complement C3 and HT on cell proliferation and apoptosis. SUNE1 xenograft mouse model was established and tumor-bearing mice were treated in water bath at a constant temperature of 43°C. Tumor samples were collected at different time points to verify the expression of complement C3 by immunohistochemical staining and western blot. The differential expressed genes after hyperthermia were analyzed by using RNA sequencing. We found that complement could enhance hyperthermia effect on suppressing proliferation and promoting apoptosis of tumor cells in NPC. Hyperthermia decreased the mRNA expression of complement C3 in tumor cells, but promoted the aggregation and activation circulating C3 in NPC tumor tissue. By using in vitro hyperthermia-treated NPC cell lines and SUNE1 xenograft tumor-bearing mice, we found that the expression of heat shock protein 5 (HSPA5) was significantly upregulated. Knockdown of HSPA5 abrogated the anti-tumor effect of hyperthermia. Moreover, we demonstrated that hyperthermia downregulated CD55 expression via HSPA5/NFκB (P65) signaling and activated complement cascade. Our findings suggest that therapeutic hyperthermia regulates complement C3 activation and suppresses tumor development via HSPA5/NFκB/CD55 pathway in NPC. Complement was involved in the anti-tumor effect of hyperthermia in vitro. Hyperthermia markedly increased the expression of heat shock protein 5 (HSPA5) and decreased the expression of CD55 which regulated the activation of complement C3 and complement cascade. Activation of HSPA5/NFκB (P65) signaling pathway resulted in a decrease in CD55 expression. [ABSTRACT FROM AUTHOR]

Gastric cancer, the fifth most prevalent cancer worldwide, is often diagnosed in advanced stages with limited treatment options. Examining the tumor microenvironment (TME) and its metabolic reprogramming can provide insights for better diagnosis and treatment. This study investigates the link between TME factors and metabolic activity in gastric cancer using bulk and single-cell RNA-sequencing data. We identified two molecular subtypes in gastric cancer by analyzing the distinct expression patterns of 81 prognostic genes related to the TME and metabolism, which exhibited significant protein-level interactions. The high-risk subtype had increased stromal content, fibroblast and M2 macrophage infiltration, elevated glycosaminoglycans/glycosphingolipids biosynthesis, and fat metabolism, along with advanced clinicopathological features. It also exhibited low mutation rates and microsatellite instability, associating it with the mesenchymal phenotype. In contrast, the low-risk group showed higher tumor content and upregulated protein and sugar metabolism. We identified a 15-gene prognostic signature representing these characteristics, including CPVL, KYNU, CD36, and GPX3, strongly correlated with M2 macrophages, validated through single-cell analysis and an internal cohort. Despite resistance to immunotherapy, the high-risk group showed sensitivity to molecular targeted agents directed at IGF-1R (BMS-754807) and the PI3K-mTOR pathways (AZD8186, AZD8055). We experimentally validated these promising drugs for their inhibitory effects on MKN45 and MKN28 gastric cells. This study unveils the intricate interplay between TME and metabolic pathways in gastric cancer, offering potential for enhanced diagnosis, patient stratification, and personalized treatment. Understanding molecular features in each subtype enriches our comprehension of gastric cancer heterogeneity and potential therapeutic targets., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lin, Yang, Wang, Huang, Wang, Chen, Xu, Cai, Khan, Liu and Lin.)