Knockdown of the T-box transcription factor Brachyury increases sensitivity of adenoid cystic carcinoma cells to chemotherapy and radiation in vitro: Implications for a new therapeutic principle

Abstract

Adenoid cystic carcinoma (AdCC) is highly metastatic and resistant to chemotherapy and radiotherapy. Recently, we reported that the T-box transcription factor Brachyury is a potential regulator of cancer stem cells (CSCs). Specifically, growth of CSCs was found to be controlled by Brachyury knockdown in AdCC. Since CSCs are resistant to chemotherapy and radiotherapy, this finding provides a new principle for therapies targeting CSCs. In the present study, we established that Brachyury knockdown suppresses chemoresistance and radioresistance in vitro. Brachyury was knocked down by transfecting Brachyury short hairpin RNA (shRNA) into the AdCC CSC cell line ACCS-M GFP. Brachyury knockdown significantly inhibited cell migration and invasion and suppressed chemoresistance. A quantitative PCR array of drug transporter genes revealed that knockdown of Brachyury caused downregulation of ATP-binding cassette transporter genes. Furthermore, ACCS-M GFP radioresistance was significantly suppressed by Brachyury knockdown. Knockdown of Brachyury significantly sensitized ACCS-M GFP cells to chemoradiotherapy. This study demonstrates that Brachyury knockdown reduces invasiveness and chemoresistance and radioresistance of CSCs in vivo. Therefore, Brachyury knockdown may be a useful therapeutic tool for sensitizing CSCs to conventional chemoradiotherapy.

Expression levels of SOX2, KLF4 and brachyury transcription factors are associated with metastasis and poor prognosis in oral squamous cell carcinoma

“…These results are consistent with those of previous studies, which revealed that silencing brachyury expression inhibits tumor formation and metastasis in human adenoid cystic carcinoma cells (19,20). In addition, a previous study revealed that brachyury expression is associated with EMT and lymph node metastasis in OSCC patients (22).…”

“…However, the role of these genes in CSCs remains unclear. Recently, the T-box transcription factor brachyury, which is essential for mesoderm formation during early development (16,17), has been found to regulate the epithelial-mesenchymal transition (EMT) and CSC potential in human salivary carcinoma cells (18)(19)(20)(21). In addition, brachyury expression was found to correlate with lymph node metastasis in OSCC (22).…”

Brachyury-YAP Regulatory Axis Drives Stemness and Growth in Cancer

“…Post-developmentally, brachyury is expressed in the testes and some thyroid tissues, but is undetectable in all other non-neoplastic adult tissues (Edwards et al, 1996; Hamilton et al, 2015). Interestingly, recent studies have reported the expression of brachyury in several epithelial cancers where it promotes growth, confers resistance to chemo- and radiotherapy, and drives epithelial-to-mesenchymal transition (EMT) (Cho et al, 2010; Fernando et al, 2010; Haro et al, 2013; Huang et al, 2013; Imajyo et al, 2012; Jezkova et al, 2016; Kobayashi et al, 2014; Larocca et al, 2013; Li et al, 2016; Miettinen et al, 2015; Palena et al, 2014; Park et al, 2008; Pinto et al, 2015; Pinto et al, 2014; Pires and Aaronson, 2014; Roselli et al, 2012; Sarkar et al, 2012; Shao et al, 2015; Shimoda et al, 2012; Vujovic et al, 2006; Xu et al, 2015; Yoshihama et al, 2016); however, the mechanistic details of how brachyury mediates these features of tumor progression have not been fully elucidated. Furthermore, the lack of brachyury expression in most adult non-neoplastic tissues and exclusive tumor-specific expression underscores its value as a potential diagnostic and therapeutic target in cancer.…”

Deregulation of Nicotinamide N-Methyltransferase and Gap Junction Protein Alpha-1 Causes Metastasis in Adenoid Cystic Carcinoma

“…For the experimental metastasis studies, 1×10 6 cells in 40 μl PBS were injected into the tongue of mice under intraperitoneal diethyl ether anesthesia, using a syringe with a 27gauge disposable needle (TOP Plastic Syringe, Tokyo, Japan). The primary tumor volumes were measured weekly, calculated as length × width × thickness, and the mice were sacrificed when the primary tumor volume reached 100 mm 3 . After sacrifice, the tongue, cervical lymph nodes, lungs, and liver were observed macroscopically.…”