Li Jun, Yu Yafeng
Department of Otolaryngology, First Affiliated Hospital of Soochow University, Suzhou, China.
Endocrine. 2025 Jan;87(1):220-233. doi: 10.1007/s12020-024-03994-y. Epub 2024 Aug 13.
Dabrafenib, an inhibitor of the B-Raf proto-oncogene (BRAF) V600E mutant, has become the major drug for targeted therapy of papillary thyroid cancer (PTC) with the BRAF V600E mutant; however, acquired resistance is inevitable.
To identify key transcription factors (TFs) involved in dabrafenib resistance and identify targets to reverse dabrafenib resistance.
Dabrafenib-resistant PTC cell lines BCPAP/DabR and K1/DabR were established, and phenotypic assays were performed to validate the malignant phenotype. RNA sequencing and bioinformatics analyses were used to identify differentially expressed genes (DEGs) and screen TFs involved in resistant phenotype-related pathways. The role of the key TF POU5F1B in dabrafenib resistance was further validated using gene gain-and-loss assays.
BCPAP/DabR and K1/DabR were resistant to dabrafenib, with a resistance index of 5-8. Resistant cells exhibited slower proliferation, strong migration, and spheroid-forming abilities. RNA sequencing screened 6233 DEGs in the resistant group, including 2687 protein-coding RNA (mRNA). Venn analysis indicated that three genes, E2F2, WNT4, and POU5F1B, were involved in resistant phenotype-related pathways and were included in the TF regulatory network. Four TFs of the three genes, POU5F1B, TBX4, FOXO4, and FOXP3, were validated, and POU5F1B showed the highest validated fold-change. Overexpression of POU5F1B in sensitive cells resulted in resistance to dabrafenib and induced a malignant phenotype, whereas silencing it sensitized the resistant cells and reversed the resistant phenotype.
This study successfully established two dabrafenib-resistant PTC cell lines, and POU5F1B could be a potential target for reversing dabrafenib resistance.
达拉非尼是一种B-Raf原癌基因（BRAF）V600E突变体抑制剂，已成为BRAF V600E突变型甲状腺乳头状癌（PTC）靶向治疗的主要药物；然而，获得性耐药是不可避免的。
鉴定参与达拉非尼耐药的关键转录因子（TFs），并确定逆转达拉非尼耐药的靶点。
建立达拉非尼耐药的PTC细胞系BCPAP/DabR和K1/DabR，并进行表型分析以验证恶性表型。采用RNA测序和生物信息学分析来鉴定差异表达基因（DEGs），并筛选参与耐药表型相关通路的TFs。使用基因增减实验进一步验证关键TF POU5F1B在达拉非尼耐药中的作用。
BCPAP/DabR和K1/DabR对达拉非尼耐药，耐药指数为5-8。耐药细胞增殖较慢，迁移能力强，具有成球能力。RNA测序在耐药组中筛选出6233个DEGs，其中包括2687个蛋白质编码RNA（mRNA）。Venn分析表明，E2F2、WNT4和POU5F1B这三个基因参与耐药表型相关通路，并被纳入TF调控网络。验证了这三个基因的四个TFs，即POU5F1B、TBX4、FOXO4和FOXP3，其中POU5F1B的验证倍数变化最高。在敏感细胞中过表达POU5F1B导致对达拉非尼耐药并诱导恶性表型，而沉默它则使耐药细胞敏感并逆转耐药表型。
本研究成功建立了两个达拉非尼耐药的PTC细胞系，POU5F1B可能是逆转达拉非尼耐药的潜在靶点。
