Identification of an appropriate cell line for the renal cell carcinoma model

Abstract

<jats:title>Abstract</jats:title> <jats:p>Background Although renal cell carcinoma (RCC) is known to be susceptible to ferroptosis, we found primary RCC cells showed resistance to ferroptosis and aimed to investigate a feasible candidate for an appropriate cell line for the RCC model. Methods Glutathione peroxidase 4 (GPX4) immunostaining was adopted in the RCC tissue microarrays. Normal human proximal tubule cells (HK-2) and RCC cell lines were used for the MTT assay, Western blotting, sphere-forming assay, and orthotopic injection of athymic Balb/c-nude mice. Results GPX4 immunostaining showed low intensity compared to the normal kidney, which coincided with the ferroptosis-susceptibility of RCC. Primary RCC cell lines (Caki-2, SNU-333, SNU-349, and SNU-1272) showed resistance to 5-fluorouracil and a GPX4 inhibitor compared to the HK-2 cells and to metastatic RCC cells (Caki-1). The Caki-2 cells showed increased GPX4 and xCT, and the SNU-333 cells showed increased ferritin heavy chain (FTH1) compared to the other RCC cells. The Caki-2 cells showed increased aSMA, fibronectin, vimentin, and SNAIL, and the SNU-333 cells showed increased aSMA, E-cadherin, and EpCAM. The Caki-2 cells showed increased Sox-2 and CD105, and the SNU-333 cells showed increased c-Myc and Lgr5. The Caki-1 and SNU-333 cells formed spheres in vitro and orthotopic RCC masses in vivo. The injected SNU-333 tumor only showed high intensities of CD10 and PAX8, consistent with the diagnostic criteria for RCC. Conclusions The primary RCC cell lines used in this study were more resistant to ferroptosis and 5-fluorouracil, and the SNU-333 cells showed tumor-initiating capacities in vitro and in vivo. These results suggest that SNU-333 might be suitable as a orthotopic RCC model for future research.</jats:p>