Lipid reprogramming induced by the TFEB-ERRα axis enhanced membrane fluidity to promote EC progression

Background: Estrogen-related receptor alpha (ERR alpha) has been reported to play a critical role in endometrial cancer (EC) progression. However, the underlying mechanism of ERR alpha-mediated lipid reprogramming in EC remains elusive. The transcription factor EB (TFEB)-ERR alpha axis induces lipid reprogramming to promote progression of EC was explored in this study. Methods: TFEB and ERR alpha were analyzed and validated by RNA-sequencing data from the Cancer Genome Atlas (TCGA). The TFEB-ERR alpha axis was assessed by dual-luciferase reporter and chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR). The mechanism was investigated using loss-of-function and gain-of-function assays in vitro. Lipidomics and proteomics were performed to identify the TFEB-ERR alpha-related lipid metabolism pathway. Pseudopods were observed by scanning electron microscope. Furthermore, immunohistochemistry and lipidomics were performed in clinical tissue samples to validate the ERR alpha-related lipids. Results: TFEB and ERR alpha were highly expressed in EC patients and correlated to EC progression. ERR alpha is the direct target ofTFEB to mediate EC lipid metabolism. TFEB-ERR alpha axis mainly affected glycerophospholipids (GPs) and significantly elevated the ratio of phosphatidylcholine (PC)/sphingomyelin (SM), which indicated the enhanced membrane fluidity. TFEB-ERR alpha axis induced the mitochondria specific phosphatidylglycerol (PG) (18:1/22:6)+H increasing. The lipid reprogramming was mainly related to mitochondrial function though combining lipidomics and proteomics. The maximum oxygen consumption rate (OCR), ATP and lipid-related genes acc, fasn, and acadm were found to be positively correlated with TFEB/ERR alpha. TFEB-ERR alpha axis enhanced generation of pseudopodia to increase the invasiveness. Mechanistically, our functional assays indicated that TFEB promoted EC cell migration in an ERRa-dependent manner via EMT signaling. Consistent with the in vitro, higher PC (18:1/18:2)+/- HCOO was found in EC patients, and those with higher TFEB/ERR alpha had deeper myometrial invasion and lower serum HDL levels. Importantly, PC (18:1/18:2) +/- HCOO was an independent risk factor positively related to ERR alpha for lymph node metastasis. Conclusion: Lipid reprogramming induced by the TFEB-ERR alpha axis increases unsaturated fatty acid (UFA)-containing PCs, PG, PC/SM and pseudopodia, which enhance membrane fluidity via EMT signaling to promote EC progression. PG (18:1/22:6) +/- H induced by TFEB-ERR alpha axis was involved in tumorigenesis and PC (18:1/18:2) +/- HCOO was the ERR alpha-dependent lipid to mediate EC metastasis.

Automated summary

This study reveals that lipid reprogramming induced by the TFEB-ERRα axis enhances the progression of endometrial cancer through EMT signaling. The TFEB-ERRα axis increases membrane fluidity, promotes pseudopod formation, and enhances cell invasion. TFEB and ERRα are highly expressed in EC patients and correlated with EC progression. Furthermore, the TFEB-ERRα axis affects lipid metabolism by altering mitochondrial function.