Abstract 5558: Stress-induced sympathetic stimulation inhibits sorafenib-induced ferroptosis in renal cell carcinoma

Abstract Background and Objective: Cancer patients are often in a chronic state of stress. There have been several reports on the relationship between stress and cancer progression, as well as the development of drug resistance. Our purpose is to investigate the effect of stress-induced sympathetic stimulation on drug resistance, especially on sorafenib, which has been reported to induce ferroptosis, in renal cell carcinoma (RCC). Methods: First, we investigated the expression of β1- (ADRB1) and β2-adrenergic receptor (ADRB2) in surgical specimens by immunohistochemistry and in RCC cell lines by RT-qPCR. Isoproterenol (ISO), a non-specific β-adrenergic receptor agonist, was added into RCC cell lines ACHN and A498 before the addition of clinically-used-drugs (sorafenib, cabozantinib, lenvatinib, and rapamycin), and cell viability was analyzed by MTS assay. BALB/c nude mice were subcutaneously implanted with ACHN on the right side and ADRB2 knockdown ACHN on the left side of the mice. The mice were divided into the following groups: saline, sorafenib, stress+saline, stress+sorafenib. To explore the mechanisms of sorafenib-induced suppression of cell viability, we examined the effects of sorafenib by adding the ferroptosis inhibitors and inducers. Result: All examined surgical RCC specimens and RCC cell lines were expressed ADRB1 and ADRB2. Drug resistance due to ISO was observed in sorafenib treatment in ACHN but not in A498. siADRB1 became resistant to sorafenib due to ISO, whereas siADRB2 was not affected. In mouse models, sorafenib inhibited tumor growth in the mock ACHN of control-reared mice. Within the vehicle-treated group, no significant differences in tumor volume due to stress exposure were observed. However, in the sorafenib-treated group, the stress-exposed group showed a greater increase in tumor volume compared to the control-reared group. In the shADRB2 ACHN, no differences in tumor volume changes were observed between the control-reared and stress-exposed groups under sorafenib treatment; both groups showed a suppression of tumor volume increase by sorafenib. In brief, ADRB2-mediated stress stimulation induced sorafenib resistance. Ferrostatin-1, a ferroptosis inhibitor, was able to significantly inhibit the effect of sorafenib in ACHN, but not in A498. The ferroptosis inducers Erastin and RSL3 decreased cell viability in both ACHN and A498 cells, and this induction of ferroptosis was suppressed in the presence of ISO. ISO significantly reduced reactive oxygen species increased by Erastin in ACHN and A-498. Conclusion: Stress-induced sympathetic stimulation inhibits sorafenib-induced ferroptosis in RCC. Citation Format: Masaki Ushijima, Sei Naito, Hiromi Ito, Osamu Ichiyanagi, Takafumi Narisawa, Norihiko Tsuchiya. Stress-induced sympathetic stimulation inhibits sorafenib-induced ferroptosis in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5558.