Expression of ubiquitin carboxyl-terminal hydrolase isozyme L1 and chromogranin A regulated via histone-modification through Rho/ERK/NFκB signaling in oxaliplatin-resistant colorectal cancer cells.

UNLABELLED: Background/Aims: Globally, colorectal cancer ranks third in causing 900,000 deaths annually. Some patients undergoing chemotherapy develop resistance, leading to metastasis. We investigated CHGA and UCHL1 proteins correlate with lymph node metastasis (J Cell Mol Med. 2023;27:2004-2020). This study aimed to analyze the relationship of CHGA and UCHL1 with the epithelial-mesenchymal transition (EMT) and the Rho/ERK/NFκB signaling pathway in OXA-resistant CRC cells.

METHODS

Resistant colorectal cancer cells (HCT-116/OxR) were established using progressive exposure to oxaliplatin (OXA). We employed siRNA, western blot, ROS assessment, apoptosis, and cell cycle assays, and animal models, to examine histone modifications regulating CHGA and UCHL1, and their impact on chemoresistance.

RESULTS

HCT-116/OxR cells displayed significantly higher OXA tolerance (elevated IC50) and reduced apoptosis compared with parental HCT-116 cells, confirmed by MTT assays and DAPI staining. Silencing CHGA and UCHL1 genes effectively suppressed the mobility and invasiveness of OXA-resistant HCT-116/OxR cells while promoting G1 phase cell cycle arrest and reducing ROS production and intracellular calcium concentrations. Notably, targeted knockdown of CHGA and UCHL1 in HCT-116/OxR cells successfully restored OXA sensitivity and EMT markers and inactivation of Rho/ERK/NFκB pathway. Further in vivo validation demonstrated that the downregulation of CHGA and UCHL1 expression markedly attenuated OXA resistance in CRC cells. Both CHGA and UCHL1-activated transcription were regulated through the Rho/ERK/NF-κB signaling pathways by histone modifications of H3K4 trimethylation.

CONCLUSIONS

In this study, Rho/ERK/NFκB signaling-mediated CHGA and UCHL1 expression, which is regulated through histone modifications and affects OXA-resistant CRC EMT outcomes, was assessed, and its potential as an early detection biomarker and prognostic indicator was explored with clinical applications.