Clarence T Sasaki1, Michael Hajek1, Sotirios G Doukas1, Dimitra P Vageli2. 1. The Yale Larynx Laboratory, Department of Surgery, Yale School of Medicine, New Haven, CT, USA. 2. The Yale Larynx Laboratory, Department of Surgery, Yale School of Medicine, New Haven, CT, USA. Electronic address: dimitra.vangeli@yale.edu.
Abstract
BACKGROUND: Prognosis for hypopharyngeal cancer is usually poor, and recurrence is common. Identifying new factors or related mechanisms that promote its progression may have clinical implications. Although, recent studies support bile reflux in hypopharyngeal carcinogenesis, it remains to be explored how bile and its related NF-κB activated pathway may further affects its progression in already established hypopharyngeal cancer. METHODS: Hypopharyngeal squamous cell carcinoma (HSCC) cell lines, FaDu and UMSCC11A, both negative for HPV, were repetitively exposed to bile acids (400 μM) at variable pH points (4.0, 5.5 and 7.0). Immunofluorescence, western blotting, luciferase assay, and qPCR were used to detect NF-κB activation, bcl-2 overexpression and gene expression. RESULTS: Bile at strongly acidic pH (4.0) potentiated the activation of NF-κB and its related mRNA phenotype in HSCC cells. IL-6, TNF-α, and BCL2 were found among the highest overexpressed genes as was previously found in HSCCs excised from patients with documented biliary reflux. An enhanced transcriptional activity of EGFR, RELA, STAT3, and WNT5Α and higher survival rates were observed in HSCC cells exposed to acidic bile compared to those exposed to bile at weakly acidic or neutral pH. CONCLUSION: Our novel findings support the observation that bile reflux has the potential for actively influencing the progression of hypopharyngeal cancer, mediated by NF-κB. In patients with hypopharyngeal cancer and known gastroesophageal reflux disease, antacid therapy may exert a role in furthering control of disease recurrence and progression.
BACKGROUND: Prognosis for hypopharyngeal cancer is usually poor, and recurrence is common. Identifying new factors or related mechanisms that promote its progression may have clinical implications. Although, recent studies support bile reflux in hypopharyngeal carcinogenesis, it remains to be explored how bile and its related NF-κB activated pathway may further affects its progression in already established hypopharyngeal cancer. METHODS:Hypopharyngeal squamous cell carcinoma (HSCC) cell lines, FaDu and UMSCC11A, both negative for HPV, were repetitively exposed to bile acids (400 μM) at variable pH points (4.0, 5.5 and 7.0). Immunofluorescence, western blotting, luciferase assay, and qPCR were used to detect NF-κB activation, bcl-2 overexpression and gene expression. RESULTS: Bile at strongly acidic pH (4.0) potentiated the activation of NF-κB and its related mRNA phenotype in HSCC cells. IL-6, TNF-α, and BCL2 were found among the highest overexpressed genes as was previously found in HSCCs excised from patients with documented biliary reflux. An enhanced transcriptional activity of EGFR, RELA, STAT3, and WNT5Α and higher survival rates were observed in HSCC cells exposed to acidic bile compared to those exposed to bile at weakly acidic or neutral pH. CONCLUSION: Our novel findings support the observation that bile reflux has the potential for actively influencing the progression of hypopharyngeal cancer, mediated by NF-κB. In patients with hypopharyngeal cancer and known gastroesophageal reflux disease, antacid therapy may exert a role in furthering control of disease recurrence and progression.