Targeting STAT3 prevents bile reflux‐induced oncogenic molecular events linked to hypopharyngeal carcinogenesis

• Published in: Journal of cellular and molecular medicine Vol. 26; no. 1; pp. 75 - 87
• Main Authors: Vageli, Dimitra P., Doukas, Panagiotis G., Siametis, Athanasios, Judson, Benjamin L.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.01.2022; John Wiley and Sons Inc
• Subjects: Antibodies; Bile; Bile Reflux; Biotechnology; Cancer; Carcinogenesis; Carcinogenesis - genetics; Cell culture; Cell Line, Tumor; Cell survival; Cloning; Dimerization; gastro‐oesophageal reflux; Gene expression; Genotype & phenotype; Head & neck cancer; head and neck cancer; Humans; hypopharyngeal cancer; Immunofluorescence; Inflammation; Interleukin 6; Kinases; laryngopharyngeal reflux; NF-kappa B - metabolism; Nifuroxazide; Oncogenes; Original; Phenotypes; Phosphorylation; Polymerase chain reaction; Proteins; Reagents; SI3‐201; Signal Transduction; siRNA; STAT3; STAT3 inhibition; Stat3 protein; STAT3 Transcription Factor - genetics; STAT3 Transcription Factor - metabolism; STA‐21; Throat cancer; Transcription activation; Tumor necrosis factor; Wnt protein; head and neck cancer; Nifuroxazide; STAT3; laryngopharyngeal reflux; STAT3 inhibition; SI3-201; STA-21; bile reflux; hypopharyngeal cancer; gastro-oesophageal reflux
• ISSN: 1582-1838; 1582-4934
• DOI: 10.1111/jcmm.17011

The signal transducer and activator of transcription 3 (STAT3) oncogene is a transcription factor with a central role in head and neck cancer. Hypopharyngeal cells (HCs) exposed to acidic bile present aberrant activation of STAT3, possibly contributing to its oncogenic effect. We hypothesized that STAT3 contributes substantially to the bile reflux‐induced molecular oncogenic profile, which can be suppressed by STAT3 silencing or pharmacological inhibition. To explore our hypothesis, we targeted the STAT3 pathway, by knocking down STAT3 (STAT3 siRNA), and inhibiting STAT3 phosphorylation (Nifuroxazide) or dimerization (SI3‐201; STA‐21), in acidic bile (pH 4.0)‐exposed human HCs. Immunofluorescence, luciferase assay, Western blot, enzyme‐linked immunosorbent assay and qPCR analyses revealed that STAT3 knockdown or pharmacologic inhibition significantly suppressed acidic bile‐induced STAT3 activation and its transcriptional activity, Bcl‐2 overexpression, transcriptional activation of IL6, TNF‐α, BCL2, EGFR, STAT3, RELA(p65), REL and WNT5A, and cell survival. Our novel findings document the important role of STAT3 in bile reflux‐related molecular oncogenic events, which can be dramatically prevented by STAT3 silencing. STA‐21, SI3‐201 or Nifuroxazide effectively inhibited STAT3 and cancer‐related inflammatory phenotype, encouraging their single or combined application in preventive or therapeutic strategies of bile reflux‐related hypopharyngeal carcinogenesis.