Abstract
Objective: All-trans retinoic acid (ATRA) has demonstrated great potential in cancer treatment; however, the molecular mechanism for the anti-tumour effects of Cellular retinoic acid-binding protein 2 (CRABP2) and ATRA in oesophageal squamous cell carcinoma (ESCC) remains unclear. Methods: A strategy of transfecting KYSE-150 cells with vectors or CRABP2 overexpression was applied in this study. Changes in cell proliferation, migration, invasion and apoptosis in OE-NC, OE-CRABP2, OE-NC + ATRA and OE-CRABP2 + ATRA groups were observed. The location of CRABP2 with ATRA and the expression of key proteins that may be involved were detected. The volume and weight of subcutaneous grafted tumours in nude mice were compared in vivo, cell morphology was observed through haematoxylin and eosin (HE) staining, and cell apoptosis was detected using TUNEL staining. Results: We determined that, in vitro, CRABP2 combined with ATRA best inhibited the proliferation, migration, invasion and cell cycle of ESCC and promoted its apoptosis. Oxidative stress, the mitochondrial pathway, p53 and the NF-κB pathway may be involved in the synergistic inhibitory effect of CRABP2 and ATRA. In vivo, tumour volume in the OE-CRABP2 + ATRA group was the smallest and tumour growth was the slowest. The HE results demonstrated improved cell differentiation in the OE-CRAB2 + ATRA group, and TUNEL staining revealed that CRABP2 and ATRA had the strongest promoting effect on cell apoptosis, with the degree of cell apoptosis the greatest with the participation of ATRA. Conclusion: The combination of CRABP2 overexpression and ATRA synergistically inhibits ESCC progression. All-trans retinoic acid may be a candidate therapy for ESCC, and CRABP2 overexpression could enhance the efficacy of ATRA treatment.