NRF1 Induces ApoEhigh Cancer-Associated Fibroblasts to Promote Stemness of Renal Cell Carcinoma

Cancer-associated fibroblasts (CAF) are abundant stromal cells in the tumor microenvironment (TME) that play a vital role in promoting tumor progression and drug resistance. The mechanisms regulating heterogeneity of CAFs in renal cell carcinoma (RCC) could represent potential targets for reprogramming the TME. In this study, we conducted single-cell RNA sequence and flow cytometry analyses that identified a CAF subset overexpressing apolipoprotein E (ApoE), which was correlated with poor survival in patients with RCC. Mechanistically, NRF1 activation in CAFs induced formation of ApoEhigh CAFs and secretion of NRG1. ApoEhigh CAFs potentiated stemness properties in the surrounding RCC cells by secreting NRG1 and subsequently activating the HER2/NF-κB pathway. Interfering with NRG1 expression or inhibiting NF-κB signaling reduced ApoEhigh CAF-induced stemness of RCC cells. Furthermore, neutralizing NRG1 enhanced the efficacy of sunitinib in RCC models in vivo. Together, these findings highlight targeting the tumor-promoting functions of ApoEhigh CAFs as a promising approach for treating advanced RCC. SIGNIFICANCE: NRF1 drives formation of ApoEhigh cancer-associated fibroblasts that secrete NRG1 to stimulate stemness of renal cell carcinoma, revealing a stromal-mediated mechanism that can be inhibited to improve treatment of advanced kidney cancer.