Journal Article

Targeting CRABP-II overcomes pancreatic cancer drug resistance by reversing lipid raft cholesterol accumulation and AKT survival signaling

Li, Ming, Che, Danian, Yu, Shuiliang, Wang, Lei, Naito, Mikihiko, Zhang, Mei, Xin, Wei, Zhou, Lan

2022

Overview

Background Resistance to standard therapy is a major reason for the poor prognosis of pancreatic ductal adenocarcinoma (PDAC). Developing novel therapy to overcome PDAC drug-resistance is urgently needed. CRABP-II was highly expressed in all PDAC but not expressed in normal pancreatic tissues and chronic pancreatitis. CRABP-II was shown to promote PDAC migration and metastasis while its potential role in promoting PDAC drug-resistance was not known. Methods A paired cohort of human primary and relapsing PDAC tissues was assessed for CRABP-II expression by immunohistochemistry. CRISPR/cas9 gene editing was used to establish CRABP-II knockout cell lines and MTT assays were performed to assess gemcitabine sensitivity in vitro. Cleaved caspase-3/PARP blots and Annexin V staining were conducted to detect cell apoptosis. Gene expression microarray, Q-PCR, western blots, Co-IP and RNA-IP were used to study the molecular function of CRABP-II. Sucrose gradient ultracentrifugation was applied to isolate lipid rafts and LC–MS-MS was used to assess cholesterol content. Both subcutaneous CDX models and orthotopic PDX models were established to examine the efficacy of SNIPER-11 and the synergistic effect between SNIPER-11 and gemcitabine in vivo. Results A higher expression of CRABP-II was found in relapsing PDAC tissue and was associated with poor prognosis. Gemcitabine-resistant cell lines exhibited increased level of CRABP-II, while CRABP-II knockout resensitized PDAC cells to gemcitabine. Mechanistically, aberrant expression of CRABP-II increased the stability of SREBP-1c mRNA through cooperation with HuR and upregulated the downstream genes of SREBP-1c to favor cholesterol uptake and accumulation in lipid rafts. Increased lipid raft cholesterol accumulation facilitated ATK survival signaling and PDAC drug resistance. The small compound SNIPER-11 treatment effectively induced CRABP-II protein degradation, induced apoptosis, and suppressed tumor growth. Combination of SNIPER-11 and gemcitabine significantly reduced the lipid raft cholesterol content in CDX/PDX and profoundly inhibited tumor progression. Conclusions These findings identified CRABP-II as a novel regulator of cholesterol metabolism and suggested that CRABP-II is a selective target for overcoming PDAC drug resistance.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: Analysis / Antimitotic agents / Antineoplastic agents / Apoptosis / Biomedical and Life Sciences / Biomedicine / Cancer Research / Carcinoma, Pancreatic Ductal - drug therapy / Carcinoma, Pancreatic Ductal - genetics / Carcinoma, Pancreatic Ductal - metabolism / Cell Line, Tumor / Cell Proliferation / Cholesterol / CRABP-II / Development and progression / Drug resistance / Drug Resistance, Neoplasm - genetics / Drug therapy / Gene expression / Gene Expression Regulation, Neoplastic / Genes / Humans / Immunohistochemistry / Immunology / Lipid raft / Membrane Microdomains / Metastasis / Neoplasm Recurrence, Local - genetics / Oncology / Pancreatic cancer / Pancreatic Neoplasms - drug therapy / Pancreatic Neoplasms - genetics / Pancreatic Neoplasms - metabolism / Pancreatitis / Physiological aspects / Prognosis / Proteolysis / Proto-Oncogene Proteins c-akt - metabolism / Receptors, Retinoic Acid - metabolism / RNA / SNIPER-11 / Snipers