RESUMO
Gastric cancer is the fifth most common malignancy worldwide. However, targeted therapy for advanced gastric cancer is still limited. Here, we report BEX2 (Brain expressed X-linked 2) as a poor prognostic factor in two gastric cancer cohorts. BEX2 expression was increased in spheroid cells, and its knockdown decreased aldefluor activity and cisplatin resistance. BEX2 was found to upregulate CHRNB2 (Cholinergic Receptor Nicotinic Beta 2 Subunit) expression, a cancer stemness-related gene, in a transcriptional manner, and the knockdown of which also decreases aldefluor activity. Collectively, these data are suggestive of the role of BEX2 in the malignant process of gastric cancer, and as a promising therapeutic target.
Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/genética , Prognóstico , Linhagem Celular Tumoral , Oncogenes , Proteínas do Tecido Nervoso/metabolismoRESUMO
Cancer stem cells (CSCs) are believed to cause cancer metastasis and recurrence. BEX2 (brain expressed X-linked gene 2) is a CSC-related gene that is expressed in dormant CSCs in cholangiocarcinoma and induces resistance against chemotherapy. The aim of the present study was to identify small compounds that have activity to inhibit BEX2 expression and result in the attenuation of CSC-related phenotypes. We screened 9600 small chemical compounds in high-throughput screening using cholangiocarcinoma cell line HuCCT1 expressing BEX2 protein fused with NanoLuc, and identified a compound, BMPP (1, 3-Benzenediol, [4-(4-methoxyphenyl)-1H-pyrazol-3-yl]). BMPP was found to exert decreasing effects on BEX2 protein expression and G0 phase population of the tumor cells, and increasing effects on ATP levels and chemotherapeutic sensitivity of the cells. These findings indicate that BMPP is a valuable chemical compound for reducing dormant CSC-related phenotypes. Thus, the identification of BMPP as a potential CSC suppressor provides scope for the development of novel therapeutic modalities for the treatment of cancers with BEX2 overexpressing CSCs.
Assuntos
Antineoplásicos/análise , Antineoplásicos/farmacologia , Descoberta de Drogas , Células-Tronco Neoplásicas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Antineoplásicos/química , Linhagem Celular Tumoral , Ensaios de Triagem em Larga Escala , Humanos , Células-Tronco Neoplásicas/efeitos dos fármacos , Reprodutibilidade dos TestesRESUMO
Cancer stem cells (CSCs) define a subpopulation of cancer cells that are resistant to therapy. However, little is known of how CSC characteristics are regulated. We previously showed that dormant cancer stem cells are enriched with a CD274low fraction of cholangiocarcinoma cells. Here we found that BEX2 was highly expressed in CD274low cells, and that BEX2 knockdown decreased the tumorigenicity and G0 phase of cholangiocarcinoma cells. BEX2 was found to be expressed predominantly in G0 phase and starvation induced the USF2 transcriptional factor, which induced BEX2 transcription. Comprehensive screening of BEX2 binding proteins identified E3 ubiquitin ligase complex proteins, FEM1B and CUL2, and a mitochondrial protein TUFM, and further demonstrated that knockdown of BEX2 or TUFM increased mitochondria-related oxygen consumption and decreased tumorigenicity in cholangiocarcinoma cells. These results suggest that BEX2 is essential for maintaining dormant cancer stem cells through the suppression of mitochondrial activity in cholangiocarcinoma.
Assuntos
Neoplasias dos Ductos Biliares/metabolismo , Colangiocarcinoma/metabolismo , Regulação Neoplásica da Expressão Gênica , Mitocôndrias/metabolismo , Células-Tronco Neoplásicas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/patologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Colangiocarcinoma/genética , Colangiocarcinoma/patologia , Proteínas Culina/genética , Proteínas Culina/metabolismo , Humanos , Mitocôndrias/genética , Mitocôndrias/patologia , Proteínas do Tecido Nervoso/genética , Consumo de Oxigênio/fisiologiaRESUMO
CD271 is a common receptor for all neurotrophins that is localized to neurons, endothelial cells, and the basal layer of the epithelium in normal tissue. Recently, we and others reported that CD271 plays essential roles in the development of squamous cell carcinoma, especially in tumor-initiating cells. Since little is known about how CD271 regulates cancer cell initiation and proliferation, antibodies that recognize different domains of CD271 are needed to enable investigation. Therefore, this study aimed to develop an antihuman CD271 antibody by immunizing mice with a CD271 antigen produced by a baculovirus. The antibody was named hCD271mAb#13, and it recognized cysteine-rich domain 1 with a higher affinity than the commercially available antibody ME20.4. We determined that hCD271mAb#13 is suitable for flow cytometry, Western blotting, immunocytochemistry, and immunohistochemistry of formalin-fixed paraffin-embedded tissue. Use of hCD271mAb#13 for CD271 labeling could enable detailed analyses of cancer cell regulation and other biological processes.
