Dapeng Lu,Lin Ma,Qingyue Zhang,Chengzhong Xing,Yanke Li
5-Fluorouracil (5-FU) is an effective drug in the treatment of colorectal cancer (CRC); however, the development of acquired resistance to 5-FU poses a great challenge in clinical practice. Through the analysis of public datasets, we found that reduced 3-Hydroxybutyrate Dehydrogenase 2 (BDH2) expression in CRC tissues predicted poor survival in CRC patients. Low expression of BDH2 in clinical CRC tissue samples predicted a higher degree of malignancy. In addition, public dataset analysis showed that GLI Pathogenesis Related 1 (GLIPR1) expression was elevated in CRC patients following 5-FU treatment, contrasting with the expression pattern of BDH2. We reported that in 5-FU-resistant CRC cell lines (LOVO/5-FU and HCT15/5-FU), BDH2 was downregulated, while the expression of GLIPR1 was increased. To explore the regulatory relationship between BDH2 and GLIPR1 in 5-FU resistance, BDH2 and GLIPR1 overexpression plasmid vectors were constructed to transfect 5-FU resistant CRC cell lines. BDH2 led to enhanced 5-FU sensitivity in 5-FU-resistant CRC cell lines and inhibited the malignant behavior of CRC-resistant cells in vitro . In nude mice with subcutaneous tumors and intraperitoneal injections of 5-FU, tumor tissues formed by BDH2-overexpressing cells exhibited slower growth and increased apoptosis. Mechanistically, the upregulation of BDH2 increases GLIPR1 promoter methylation, mediated by DNA methyltransferases, thereby inhibiting GLIPR1 expression. High expression of GLIPR1 reduces 5-FU sensitivity in 5-FU-resistant CRC cell lines, which abolished the impact of BDH2 expression. These results suggest that BDH2 inhibits GLIPR1 expression by increasing GLIPR1 promoter methylation, thereby enhancing 5-FU sensitivity of 5-FU-resistant CRC cell lines and inhibiting CRC progression.
Platinum-based and pyrimidine drugs are first-line treatments for gastric cancer (GC), but their efficacy is often affected by drug resistance. High spalt-like transcription factor 4 (SALL4) expression is associated with poor prognosis, but its role in 5-fluorouracil (5-FU) resistance is not yet clear. In this study, we investigated the effect of SALL4 on 5-FU resistance in GC cells by bioinformatics analysis, real-time quantitative reverse transcription polymerase chain reaction, cell counting kit-8, colony formation assay, and western blot. The results showed that SALL4 was highly expressed in GC and significantly correlated with the fatty acid oxidation (FAO) pathway. Knockdown of SALL4 resulted in a notable attenuation of cellular proliferative capacity and heightened susceptibility to 5-FU resistance in GC cells, while overexpression of SALL4 enhanced 5-FU resistance. Rescue assays confirmed that SALL4 fostered 5-FU resistance in GC cells by enhancing FAO. Our research confirmed that SALL4 promoted the resistance of GC cells to 5-FU by enhancing the FAO pathway. This suggests that drug development targeting SALL4 may help overcome chemotherapy resistance in GC.
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