Functions of CRABP2 in tumorigenesis and progression / 中国临床药理学与治疗学

Retinoic acid (RA) is a metabolic intermediate of vitamin A, which plays an important role in embryonic development and cell growth and differentiation. Cellular retinoic acid-binding proteins 2 (CRABP2) are a group of low-molecular weight intracellular proteins whose primary physiological function is to transport RA to the nucleus. Generally, CRABP2 binds to the retinoic acid receptor (RAR), then regulates specific downstream signaling pathways to function. Abnormal expression of CRABP2 was closely related to several human malignant tumors, and could affect the tumor occurrence and development through regulating multiple growth or apoptosis associated pathways or key biological molecules. Therefore, CRABP2 may be considered as a new diagnostic and prognostic marker for cancer, and a new therapeutic target for malignant tumors. Our present article summarizes the relationship between CRABP2 and tumor progression, drug resistance and prognosis, so as to provide reference for the future research.

Plasma CRABP2 as a Novel Biomarker in Patients with Non-Small Cell Lung Cancer

BACKGROUND: Lung cancer is the most common cause of cancer-related mortality worldwide. We previously reported the identification of a new genetic marker, cellular retinoic acid binding protein 2 (CRABP2), in lung cancer tissues. The aim of this study was to assess plasma levels of CRABP2 from patients with non-small cell lung cancer (NSCLC). METHODS: Blood samples that were collected from 122 patients with NSCLC between September 2009 and September 2013 were selected for the analysis, along with samples from age- (± 5 years), sex-, and cigarette smoking history (± 10 pack-years [PY])-matched controls from the Korea Biobank Network. The control specimens were from patients who were without malignancies or pulmonary diseases. We measured plasma levels of CRABP2 using commercially available enzyme-linked immunosorbent assay kits. RESULTS: The mean age of the NSCLC patients was 71.8 ± 8.9 years, and the median cigarette smoking history was 32 PY (range, 0–150 PY). Plasma CRABP2 levels were significantly higher in patients with NSCLC than in the matched controls (37.63 ± 28.71 ng/mL vs. 24.09 ± 21.09 ng/mL, P < 0.001). Higher plasma CRABP2 levels were also correlated with lower survival rates in NSCLC patients (P = 0.014). CONCLUSION: Plasma CRABP2 levels might be a novel diagnostic and prognostic marker in NSCLC.

New ligands of the Cellular Retinoic Acid-Binding Protein 2 (CRABP2) suggest a role for this protein in chromatin remodeling

Retinoic acid (RA) regulates the transcription of a series of genes involved in cell proliferation, differentiation and apoptosis by binding to the RA Receptor (RAR) and Retinoid X Receptor (RXR) heterodimers. The cellular retinoic acid-binding protein 2 (CRABP2) is involved in the transport of RA from the cytosol to specific RA receptors in the nucleus, acting as a coactivator of nuclear retinoid receptors. In order to have a better understanding of the role of CRABP2 in RA signaling, we used the yeast two-hybrid system as a tool for the identification of physical protein-protein interactions. Twenty-three putative CRABP2-interacting proteins were identified by screening in the presence of RA, five of which are related to transcription regulation or, more specifically, to the process of chromatin remodeling: t-complex 1 (TCP1); H3 histone, family 3A (H3F3A); H3 histone, family 3B (H3F3B); β-tubulin (TUBB) and SR-related CTD-associated factor 1 (SCAF1). These results suggest a more direct role for CRABP2 in chromatin remodeling and may be a starting point for the elucidation of the fine-tuning control of transcription by RA receptors...