Tianjin Medical Journal ›› 2022, Vol. 50 ›› Issue (10): 1043-1049.doi: 10.11958/20220566

• Experimental Research • Previous Articles     Next Articles

Study on the mechanism of resveratrol reversing temozolomide resistance in glioma cells by regulating Wnt/β-catenin pathway through BRD4

LI Zhenjiang(), SUN Dechao, KONG Chenxu, GENG Yadong, XU Chenyang, DING Bingqian   

  1. Department of Neurosurgery, Huaihe Hospital of Henan University, Kaifeng 475000, China
  • Received:2022-04-13 Revised:2022-05-07 Published:2022-10-15 Online:2022-10-20

Abstract:

Objective To explore whether the effect of resveratrol in reversing temozolomide (TMZ) resistance in glioma cells was related to the regulation of bromodomain-containing protein 4 (BRD4) and Wnt/β-catenin pathways. Methods Human glioma TMZ low-sensitivity cell line (U138), high-sensitivity cell line (U251) and drug-resistant cell line (T98G) were obtained, and Western blot assay was performed to detect the protein expressions of BRD4, Wnt3a, β-catenin and TMZ drug resistance protein (MGMT). T98G cell line was taken and divided into the control group 1 (adding 100 μmoL/L TMZ), the RES1 group (adding 50 μmoL/L RES) and RES+TMZ group (adding 100 μmoL/L TMZ and 50 μmoL/L RES). Cell proliferation and apoptosis were measured by CCK-8 method and flow cytometry. Protein expressions of BRD4, Wnt3a, β-catenin and MGMT were measured by Western blot assay. In order to analyze the effect of BRD4 overexpression on TMZ resistance, on the basis of adding 100 μmoL/L TMZ, T98G cells were transfected with BRD4 overexpression plasmid (pcDNA BRD4) or added 50 μmoL/L RES, and cells were divided into the pcDNA NC group, the pcDNA BRD4 group, the RES2 group and the RES+pcDNA BRD4 group. In order to verify the regulatory effect of BRD4 on Wnt3a/β-catenin pathway, on the basis of adding 100 μmoL/L TMZ, BRD4 inhibitor JQ1 and the Wnt3a/β-catenin pathway activator LiCl were added, and cells were divided into the control 2 groups, the JQ1 group and the JQ1+LiCl group. T98G cells were inoculated into the left scapular region of nude mice, and treated with RES, TMZ and/or JQ1. Protein expressions of Ki67, BRD4, MGMT and Wnt3a/β-catenin in tumor were measured. Results Compared with the high-susceptibility strain (U251), the expressions of BRD4, Wnt3a, β-catenin and MGMT increased in sequence in the low-susceptibility strain (U138) and the drug-resistant strain (T98G) (P<0.05). Compared with the control group 1, RES intervention could inhibit the expression and proliferation of BRD4, Wnt3a/β-catenin and MGMT proteins in T98G cells, promote apoptosis and reverse cell drug resistance (P<0.05). PcDNA BRD4 could reverse the anti-proliferative and pro-apoptotic effects of RES. BRD4 inhibitor JQ1 could inhibit the expression and proliferation of BRD4, Wnt3a/β-catenin and MGMT proteins in T98G cells, and promote apoptosis (P<0.05). LiCl could reverse the anti-proliferative and pro-apoptotic effects of JQ1. RES alone or in combination with JQ1 could activate the inhibitory effect of TMZ on Wnt3a/β-catenin pathway, MGMT expression and cell proliferation in tumors (P<0.05). Conclusion RES can reverse TMZ resistance of glioma T98G cells by downregulating BRD4 and thereby inhibiting the activation of Wnt3a/β-catenin pathway.

Key words: glioma, drug resistance, neoplasm, Wnt signaling pathway, beta catenin, resveratrol, temozolomide, bromodomain-containing protein 4

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