{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:47:29Z","timestamp":1787028449920,"version":"build-2736575974"},"reference-count":90,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,4,20]],"date-time":"2021-04-20T00:00:00Z","timestamp":1618876800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Pepsin refluxate is considered a risk factor for laryngopharyngeal carcinogenesis. Non-acidic pepsin was previously linked to an inflammatory and tumorigenic effect on laryngopharyngeal cells in vitro. Yet there is no clear evidence of the pepsin-effect on a specific oncogenic pathway and the importance of pH in this process. We hypothesized that less acidic pepsin triggers the activation of a specific oncogenic factor and related-signalling pathway. To explore the pepsin-effect in vitro, we performed intermittent exposure of 15 min, once per day, for a 5-day period, of human hypopharyngeal primary cells (HCs) to pepsin (1 mg\/mL), at a weakly acidic pH of 5.0, a slightly acidic pH of 6.0, and a neutral pH of 7.0. We have documented that the extracellular environment at pH 6.0, and particularly pH 7.0, vs. pH 5.0, promotes the pepsin-effect on HCs, causing increased internalized pepsin and cell viability, a pronounced activation of EGFR accompanied by NF-\u03baB and STAT3 activation, and a significant upregulation of EGFR, AKT1, mTOR, IL1\u03b2, TNF-\u03b1, RELA(p65), BCL-2, IL6 and STAT3. We herein provide new evidence of the pepsin-effect on oncogenic EGFR activation and its related-signaling pathway at neutral and slightly acidic pH in HCs, opening a window to further explore the prevention and therapeutic approach of laryngopharyngeal reflux disease.<\/jats:p>","DOI":"10.3390\/ijms22084275","type":"journal-article","created":{"date-parts":[[2021,4,20]],"date-time":"2021-04-20T13:58:04Z","timestamp":1618927084000},"page":"4275","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Pepsin Promotes Activation of Epidermal Growth Factor Receptor and Downstream Oncogenic Pathways, at Slightly Acidic and Neutral pH, in Exposed Hypopharyngeal Cells"],"prefix":"10.3390","volume":"22","author":[{"given":"Panagiotis G.","family":"Doukas","sequence":"first","affiliation":[{"name":"The Yale Larynx Laboratory, Department of Surgery (Otolaryngology), Yale School of Medicine, New Haven, CT 06510, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9852-5790","authenticated-orcid":false,"given":"Dimitra P.","family":"Vageli","sequence":"additional","affiliation":[{"name":"The Yale Larynx Laboratory, Department of Surgery (Otolaryngology), Yale School of Medicine, New Haven, CT 06510, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Clarence T.","family":"Sasaki","sequence":"additional","affiliation":[{"name":"The Yale Larynx Laboratory, Department of Surgery (Otolaryngology), Yale School of Medicine, New Haven, CT 06510, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Benjamin L.","family":"Judson","sequence":"additional","affiliation":[{"name":"The Yale Larynx Laboratory, Department of Surgery (Otolaryngology), Yale School of Medicine, New Haven, CT 06510, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,20]]},"reference":[{"key":"ref_1","first-page":"512","article-title":"Laryngopharyngeal Reflux and Functional Laryngeal Disorder: Perspective and Common Practice of the General Gastroenterologist","volume":"14","author":"Patel","year":"2018","journal-title":"Gastroenterol. 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