PLC? regulates prostate cancer mitochondrial oxidative metabolism and migration via upregulation of Twist1.

ABSTRACT: BACKGROUND:Metabolic rewiring is a common feature of many cancer types, including prostate cancer (PCa). Alterations in master genes lead to mitochondrial metabolic rewiring and provide an appealing target to inhibit cancer progression and improve survival. Phospholipase C (PLC)? is a regulator of tumor generation and progression. However, its role in mitochondrial metabolism remains unclear. METHODS:The GEO, The Cancer Genome Atlas, and the GTEx databases were used to determine Twist1 mRNA levels in tumors and their non-tumor counterparts. Fifty-five PCa and 48 benign prostatic hypertrophy tissue samples were tested for the presence of PLC? and Twist1 immunohistochemically. An association between PLC? and Twist1 was determined by Pearson's correlation analysis. PLC? was knocked down with a lentiviral short hairpin RNA. Mitochondrial activity was assessed by measuring the oxygen consumption rate. Western blotting analyses were used to measure levels of PPAR?, Twist1, phosphorylated (p)-Twist1, p-MEK, p-ERK, p-P38, and p-c-Jun N-terminal kinase (JNK). Cells were treated with inhibitors of MEK, JNK, and P38 MAPK, and an agonist and inhibitor of peroxisome proliferator activated receptor (PPAR) ?, to evaluate which signaling pathways were involved in PLC?-mediated Twist1 expression. The stability of Twist1 was determined after blocking protein synthesis with cycloheximide. Reporter assays utilized E-cadherin or N-cadherin luciferase reporters under depletion of PLC? or Twist1. Transwell assays assessed cell migration. Finally, a nude mouse tumor xenograft assay was conducted to verify the role of PLC? in tumor formation. RESULTS:Our findings revealed that the expression of PLC? was positively associated with Twist1 in clinical PCa samples. PLC? knockdown promoted mitochondrial oxidative metabolism in PCa cells. Mechanistically, PLC? increased phosphorylation of Twist1 and stabilized the Twist1 protein through MAPK signaling. The transcriptional activity of Twist1, and the Twist1-mediated epithelial-to-mesenchymal transition, cell migration, and transcription regulation, were suppressed by PLC? knockdown and by blocking PPAR? nuclear translocation. The tumor xenograft assay demonstrated that PLC? depletion diminished PCa cell tumorigenesis. CONCLUSIONS:These findings reveal an undiscovered physiological role for PLC? in the suppression of mitochondrial oxidative metabolism that has significant implications for understanding PCa occurrence and migration.

SUBMITTER: Fan J 

PROVIDER: S-EPMC6683382 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature