Proanthocyanidins mitigate bile acid‐induced changes in GSTT2 levels in a panel of racially diverse patient‐derived primary esophageal cell cultures

Abstract

Persistent and symptomatic reflux of gastric and duodenal contents, known as gastroesophageal reflux disease (GERD), is the strongest risk factor for esophageal adenocarcinoma (EAC). Despite similar rates of GERD and other risk factors across racial groups, EAC progression disproportionately impacts Caucasians. We recently reported that elevated tissue levels of the detoxification enzyme GSTT2 in the esophagi of Blacks compared to Caucasians may contribute protection. Herein, we extend our research to investigate whether cranberry proanthocyanidins (C‐PAC) mitigate bile acid‐induced damage and GSTT2 levels utilizing a racially diverse panel of patient‐derived primary esophageal cultures. We have shown that C‐PACs mitigate reflux‐induced DNA damage through GSTT2 upregulation in a rat esophageal reflux model, but whether effects are recapitulated in humans or differentially based on race remains unknown. We isolated normal primary esophageal cells from Black and Caucasian patients and assessed GSTT2 protein levels and cellular viability following exposure to a bile acid cocktail with and without C‐PAC treatment. Constitutive GSTT2 levels were significantly elevated in Black (2.9‐fold) compared to Caucasian patients, as were GSTT2 levels in Black patients with GERD. C‐PAC treatment induced GSTT2 levels 1.6‐fold in primary normal esophageal cells. GSTT2 induction by C‐PAC was greatest in cells with constitutively low GSTT2 expression. Overall, C‐PAC mitigated bile‐induced reductions of GSTT2 and subsequent loss of cell viability regardless of basal GSTT2 expression or race. These data support that C‐PAC may be a safe efficacious agent to promote epithelial fitness through GSTT2 induction and in turn protect against bile acid‐induced esophageal injury.

Cranberry Polyphenols in Esophageal Cancer Inhibition: New Insights

“…Furthermore, MMP-9 expression is inversely correlated with protein levels of the phase II detoxification glutathione-s-transferase pi (GSTP1), with increased levels of GSTP1 in normal patients and those with esophagitis [ 79 ]. We recently showed that C-PAC increases levels of the phase 2 detoxification enzyme glutathione-s-transferase theta 2 (GSTT2) and protects against acidified bile acid induced cell death in patient-derived primary normal esophageal cells [ 80 ]. Thus, the ability of cranberry constituents to favorably impact esophageal cells, both primary and immortalized cell cultures, across a range of histopathology lends support for the investigation of cranberry constituents in cohorts at increased risk for progression to EAC, such as BE patients.…”

Prebiotic proanthocyanidins inhibit bile reflux-induced esophageal adenocarcinoma through reshaping the gut microbiome and esophageal metabolome

“…Beyond dysbiosis, reflux components are well documented to induce DNA damage in esophageal cells and to stimulate cytokine-mediated inflammation further contributing toward epithelial injury, immune cell migration, genetic instability and cancer progression (21,24). Repeated exposure to refluxate also leads to diminished defense mechanisms as evidenced by esophageal barrier dysfunction and reduced levels of esophageal DNA repair enzymes, inferring compromised repair capacity in reflux-exposed esophageal epithelium (21,25,26). Reflux-induced mucosal damage coupled with esophageal barrier dysfunction allows for increased interaction between pathogenic bacteria and the epithelium further promoting esophageal injury and risk for EAC progression.…”

Prebiotic proanthocyanidins inhibit bile reflux-induced esophageal adenocarcinoma through reshaping the gut microbiome and esophageal metabolome

“…Our laboratory has previously shown the cancer inhibitory potential of C-PAC utilizing human esophageal normal, BE, and EAC cell lines and OE19 EAC tumor xenografts ( 22 , 34 – 36 , 50 ). The current study extends evaluation of C-PAC to a more translationally relevant reflux-induced EAC model.…”

“…Beyond dysbiosis, reflux components are well documented to induce DNA damage in esophageal cells and to stimulate cytokine-mediated inflammation, further contributing toward epithelial injury, immune cell migration, genetic instability, and cancer progression ( 18 , 21 ). Repeated exposure to refluxate also leads to diminished defense mechanisms, as evidenced by esophageal barrier dysfunction and reduced levels of esophageal DNA repair enzymes, suggesting compromised repair capacity in reflux-exposed esophageal epithelium ( 18 , 22 , 23 ). Reflux-induced mucosal damage coupled with esophageal barrier dysfunction allows for increased interaction between pathogenic bacteria and epithelium, further promoting esophageal injury and risk for EAC progression.…”