PRKN mediates the ubiquitination of SCAF8 to reduce the mRNA stability of KLF5 and its transcriptional activation of EFNA3 in colorectal cancer.

Abstract

Background: Dysregulation in glycolysis within the tumor microenvironment is a hallmark in the context of colorectal cancer (CRC). We aimed to identify critical drivers of glycolysis in CRC and decipher the underlying mechanism.

Methods: Through combined gene interference in CRC cells using lentivirus and treatment with glycolysis activator DASA-58, we measured glycolytic flux to evaluate how molecular mechanisms influence tumor cell activity via glycolysis. CRC cells were cocultured with NK and CD8⁺ T cells to analyze the anti-tumor immune response. A patient-derived xenograft mouse model and a CMT93 cell-derived allograft mouse model were developed for analyzing CRC growth, metastasis, and immune evasion.

Results: EFNA3 was elevated in CRC tissues and cell lines. The glycolytic activity, proliferative, migratory, invasive, and pro-angiogenic effects of the CRC cells were reduced, and the anti-tumor response of the CD⁸⁺ T and NK cells was enhanced after EFNA3 knockdown in CRC cells. Tumors formed by CMT93 cells with EFNA3 knockdown exhibited reduced metastasis and an increased proportion of anti-tumor immune cells infiltrated. Overexpression of KLF5 promoted EFNA3 transcription, and SCAF8 enhanced KLF5 mRNA stability. Downregulation of PRKN in CRC enhanced the SCAF8 protein expression through ubiquitination. PRKN upregulation blocked glycolysis and suppressed the malignant behavior of CRC cells, whereas the anticancer ability of PRKN was reversed by SCAF8/KLF5/EFNA3 overexpression.

Conclusions: Activating the E3 ubiquitin ligase activity of PRKN to suppress EFNA3 expression represents a promising therapeutic strategy for the clinical treatment of CRC.