Abstract A023: Loss of the transcription factor ATF4 reprograms glucose metabolism in clear cell renal cell carcinoma

Abstract Clear cell renal cell carcinoma (ccRCC) is the most common form of kidney cancer in adults. Transcriptomics and metabolomics studies of human ccRCC kidneys reported by others and shown in this report demonstrate upregulated glycolytic metabolism and downregulated mitochondrial oxidative processes. Abnormal and pseudohypoxic activation of hypoxia-inducible factor-1α (HIF1α) and HIF2α signaling has been considered one of the major causes of abnormal metabolisms in ccRCC. We have generated a murine TRAnsgenic model of Cancer of the Kidney (TRACK) that expresses a triple-mutant (P402A, P564A, and N803A) human HIF1α construct in murine proximal tubule cells (PTCs), interfering with the proteasomal degradation of this mutant HIF1α and enhancing its transcriptional activity in the kidneys. This mouse model mimics the early stage of ccRCC. Using this mouse model, our studies found that ATF4, a transcription factor responding to stress, is induced in ccRCC kidneys. In drosophila and cultured cells, ATF4 has been shown to be involved in regulations of glycolysis and mitochondrial oxidation. However, whether or how ATF4 regulates glycolysis and mitochondrial oxidation in ccRCC is unknown. To study the role of ATF4 in regulation of glycolysis and mitochondrial oxidation, we generated WT and TRACK ATF4-knockout (KO) mice and human RCC4 ATF4-KO cells. Using these mouse and cell lines, we demonstrate that ATF4 deletion inhibits overall glycolysis and enhances mitochondrial oxidative activities in ccRCC. Our transcriptomics and metabolomics studies in TRACK mice cooperatively show that ATF4 deletion suppresses two major steps in glycolysis and enhances several steps in the TCA cycle, particularly the step producing malate catalyzed by fumarate dehydrogenase. Our glucose tracing experiments with parental and ATF4-KO RCC4 cells demonstrate that ATF4 deletion reduced most metabolites in glycolysis and increased all metabolites in the TCA cycle, hence hindering glucose flux and enhancing the TCA cycle flux. Additional studies using Seahorse XFe96 analyzer demonstrate that inhibition of glycolysis by ATF4 deletion reduced glycolytic capacity and reserve. Enhanced mitochondrial oxidative activities by ATF4 deletion increased glucose oxidation. Together, these results demonstrate that ATF4 regulates glucose metabolism in ccRCC. ATF4 deletion can switch the carbohydrate metabolism from anaerobic to aerobic processes. Citation Format: Yuling Chi, Qiuying Chen, Eduardo Mere Del Aguila, Steven S. Gross, John A. Wagner, Shannon M. Reilly, David M. Nanus, Lorraine J. Gudas. Loss of the transcription factor ATF4 reprograms glucose metabolism in clear cell renal cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Innovations in Kidney Cancer Research: From Molecular Insights to Therapeutic Breakthroughs; 2026 Mar 13-16; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(5_Suppl_2):Abstract nr A023.