Knock out of ELAVL1 affects steroid synthesis in adrenocortical carcinoma cell line NCI-H295R and leads to a less malignant phenotype

Abstract

Introduction: Adrenocortical carcinoma (ACC) is a rare malignancy of the adrenal gland. With a 5-year-survival rate below 50% and no curative treatment options in advanced stages new therapeutic options in ACC are needed. Analyzing the ACC cohort of the cancer genome atlas we found a significant negative correlation of the expression level of a gene called Embryonic Lethal Abnormal Vision Like 1 (ELAVL1) and ACC patient survival. ELAVL1 has been described to be unfavorable in a lot of different tumor entities, but its function in ACC progression is still unknown. Methods: To evaluate the function of ELAVL1 in ACC progression we performed a CRISPR/Cas9 mediated knock out (KO) of the ELAVL1 gene in the ACC cell line NCI-H295R. The KO was confirmed on DNA level via Sanger sequencing and on protein level via immunofluorescence and western blot. Transcriptome changes were analyzed by next generation RNA sequencing (NGS). To characterize changes in cell function we performed soft agar colony forming assays and evaluated changes in steroid production via mass spectrometry. Results: Via CRISPR/Cas9 we knocked out ELAVL1 in NCI-H295R cells. NGS data showed 6926 significantly deregulated genes in ELAVL1-KO cells compared to control cells. There was an upregulation of 3468 genes, while 3458 genes showed a lower expression in ELAVL1 KO cells. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed a significant upregulation of 29 genes associated with aldosterone synthesis and a significant downregulation of 87 genes associated with pathways in cancer. Analyzing cell function via soft agar colony forming assays an impaired colony forming ability in ELAVL1 KO cells was seen. Furthermore, we could prove significant changes in steroid production. ELAVL1 KO led to an inhibition of androgen and glucocorticoid synthesis and an enhancement in mineralocorticoid synthesis. These changes could not only be proven by measuring steroid concentrations in cell culture supernatants, but also by NGS showing a downregulation of the genes CYP17A1 and CYP11B1 and an upregulation of CYP21A2 and CYP11B2. Conclusion: Our study showed that ELAVL1 affects the regulation of around 7000 genes in the ACC cell line NCI-H295R. Especially the inhibition of glucocorticoid synthesis shows that ELAVL1 may be a new target for therapeutic approaches in ACC treatment since hypercortisolism is one of the main symptoms in ACC and a negative prognostic factor for patient survival. The authors have nothing to disclose. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.