Calpain‐2 triggers prostate cancer metastasis via enhancing CRMP4 promoter methylation through NF‐κB/DNMT1 signaling pathway

• Published in: The Prostate Vol. 78; no. 9; pp. 682 - 690
• Main Authors: Gao, Xin, Mao, Yun‐Hua, Xiao, Chutian, Li, Ke, Liu, Wei, Li, Liao‐Yuan, Pang, Jun
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-06-2018
• Subjects: Aged; Calpain; Calpain - biosynthesis; Cell Line, Tumor; collapsing response mediator protein‐4; CpG Islands; DNA (Cytosine-5-)-Methyltransferase 1 - biosynthesis; DNA (Cytosine-5-)-Methyltransferase 1 - metabolism; DNA Methylation; DNA methyltransferase; DNMT1 protein; Gene Expression Regulation, Neoplastic - physiology; Gene silencing; Genes, Tumor Suppressor - physiology; Humans; Male; Mediator protein; Membrane Glycoproteins - metabolism; Metastases; Metastasis; Middle Aged; Muscle Proteins - biosynthesis; Muscle Proteins - metabolism; Neoplasm Metastasis - genetics; Neoplasm Metastasis - physiopathology; Neuropilin-2 - metabolism; Nuclear transport; Phosphorylation; Promoter Regions, Genetic - physiology; Prostate cancer; Prostatic Hyperplasia - metabolism; prostatic neoplasm; Prostatic Neoplasms - metabolism; Prostatic Neoplasms - pathology; Prostatic Neoplasms - secondary; Prostatic Neoplasms, Castration-Resistant - metabolism; Prostatic Neoplasms, Castration-Resistant - secondary; Receptor Cross-Talk - physiology; RelA protein; Retrospective Studies; Semaphorins - metabolism; Signal Transduction; Statistical analysis; Transcription Factor RelA - metabolism; Up-Regulation; Vascular Endothelial Growth Factor C - biosynthesis; collapsing response mediator protein-4; calpain; metastasis; prostatic neoplasm
• ISSN: 0270-4137; 1097-0045
• DOI: 10.1002/pros.23512

Background
Metastasis is the major cause of cancer‐specific death in patients with prostate cancer (PCa). We previously reported that collapsing response mediator protein‐4 (CRMP4) is a PCa metastasis‐suppressor gene and the hypermethylation in CRMP4 promoter is responsible for the transcription repression in metastatic PCa. However, the underlying mechanisms remain unknown. In this study, we aimed to investigate the role of calpain‐2 in CRMP4 promoter hypermethylation and its functional modulation in PCa metastasis.
Methods
Calpain‐2 expression in PCa tissues (n = 87) and its specific mechanisms of functional modulation in CRMP4 expression via limited enzymatic cleavage was investigated. We then focused on the cooperative crosstalk of calpain‐2 and NF‐κB RelA/p65 in CRMP4 promoter methylation for the initiation of PCa metastasis. Statistical differences between groups were determined using a two‐tailed Student's t‐test. P < 0.05 indicated statistically significant.
Results
Calpain‐2 was differentially upregulated in metastatic PCa compared with localized PCa. Moreover, calpain‐2 cleaved CRMP4 into the N‐terminally fragment which promoted migration and invasion in PCa cells via nuclear translocation and activation of E2F1‐mediated DNA methyltransferase 1 (DNMT1) expression. NF‐κB RelA/p65 recruited DNMT1 to bind to and methylate CRMP4 promoter in which Serine276 phosphorylation of p65 was essential. Furthermore, CRMP4 exhibited anti‐metastatic function via inhibiting the expression of VEGFC through Semaphorin3B‐Neuropilin2 signaling.
Conclusion
Calpain‐2 may contribute to the promoter methylation of CRMP4 to repress its transcription, leading to the metastasis of PCa via enhancing VEGFC expression.