Therapeutic Hyperthermia Regulates Complement C3 Activation And Suppresses Tumor Development Through HSPA5/NFκB/CD55 Pathway In Nasopharyngeal Carcinoma

Background: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 remains unclear.Complement C3 has been reported to participate in the activation of immune system in the tumor microenvironment(TME),leading to tumor growth inhibition.Purpose: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).Methods:The serum levels of complement C3 before and after hyperthermia treatment in patients with NPC were analyzed.NPC cell line 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.Results: We found that complement from human serum could enhance hyperthermia effect on suppressing proliferation and promoting apoptosis of tumor cells in NPC.Hyperthermia decreased the m RNA expression of complement C3 but promoted the enrichment of circulating C3 in NPC tumor.By using in vitro hyperthermia-treated NPC cell lines and RNA-sequencing,we found that the expression of heat shock protein 5(HSPA5)was significantly up-regulated.Knockdown of HSPA5 abrogated the anti-tumor effect of hyperthermia.Moreover,we demonstrated that hyperthermia down-regulated CD55 expression via HSPA5/ NFκB(P65)signaling and activated complement cascade.Conclusions:Our findings suggest that therapeutic hyperthermia regulates complement C3 expression and suppresses tumor development via HPSA5/NFκB/CD55 pathway in NPC.