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

The gut and local esophageal microbiome progressively shift from healthy commensal bacteria to inflammation-linked pathogenic bacteria in patients with gastroesophageal reflux disease, Barrett's esophagus, and esophageal adenocarcinoma (EAC). However, mechanisms by which microbial communities and metabolites contribute to reflux-driven EAC remain incompletely understood and challenging to target. Herein, we utilized a rat reflux-induced EAC model to investigate targeting the gut microbiome-esophageal metabolome axis with cranberry proanthocyanidins (C-PAC) to inhibit EAC progression. Sprague-Dawley rats, with or without reflux induction, received water or C-PAC ad libitum (700 μg/rat/day) for 25 or 40 weeks. C-PAC exerted prebiotic activity abrogating reflux-induced dysbiosis and mitigating bile acid metabolism and transport, culminating in significant inhibition of EAC through TLR/NF-κB/TP53 signaling cascades. At the species level, C-PAC mitigated reflux-induced pathogenic bacteria (Streptococcus parasanguinis, Escherichia coli, and Proteus mirabilis). C-PAC specifically reversed reflux-induced bacterial, inflammatory, and immune-implicated proteins and genes, including Ccl4, Cd14, Crp, Cxcl1, Il6, Il1b, Lbp, Lcn2, Myd88, Nfkb1, Tlr2, and Tlr4, aligning with changes in human EAC progression, as confirmed through public databases. C-PAC is a safe, promising dietary constituent that may be utilized alone or potentially as an adjuvant to current therapies to prevent EAC progression through ameliorating reflux-induced dysbiosis, inflammation, and cellular damage.

Cranberry Proanthocyanidins Mitigate Reflux-Induced Transporter Dysregulation in an Esophageal Adenocarcinoma Model

We recently reported that cranberry proanthocyanidins (C-PACs) inhibit esophageal adenocarcinoma (EAC) by 83% through reversing reflux-induced bacterial, inflammatory and immune-implicated proteins and genes as well as reducing esophageal bile acids, which drive EAC progression. This study investigated whether C-PACs' mitigation of bile reflux-induced transporter dysregulation mechanistically contributes to EAC prevention. RNA was isolated from water-, C-PAC- and reflux-exposed rat esophagi with and without C-PAC treatment. Differential gene expression was determined by means of RNA sequencing and RT-PCR, followed by protein assessments. The literature, coupled with the publicly available Gene Expression Omnibus dataset GSE26886, was used to assess transporter expression levels in normal and EAC patient biopsies for translational relevance. Significant changes in ATP-binding cassette (ABC) transporters implicated in therapeutic resistance in humans (i.e., Abcb1, Abcb4, Abcc1, Abcc3, Abcc4, Abcc6 and Abcc10) and the transport of drugs, xenobiotics, lipids, and bile were altered in the reflux model with C-PACs' mitigating changes. Additionally, C-PACs restored reflux-induced changes in solute carrier (SLC), aquaporin, proton and cation transporters (i.e., Slc2a1, Slc7a11, Slc9a1, Slco2a1 and Atp6v0c). This research supports the suggestion that transporters merit investigation not only for their roles in metabolism and therapeutic resistance, but as targets for cancer prevention and targeting preventive agents in combination with chemotherapeutics.

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

The gut and local esophageal microbiome progressively shift from healthy commensal bacteria to inflammatory-linked pathogenic bacteria in patients with gastroesophageal reflux disease, Barrett's esophagus and esophageal adenocarcinoma (EAC). However, mechanisms by which microbial communities and metabolites contribute to reflux-driven EAC remain incompletely understood and challenging to target. Herein, we utilized a rat reflux-induced EAC model to investigate targeting the gut microbiome-esophageal metabolome axis with cranberry proanthocyanidins (C-PAC) to inhibit EAC progression. Sprague Dawley rats, with or without reflux-induction received water or C-PAC ad libitum (700 µg/rat/day) for 25 or 40 weeks. C-PAC exerted prebiotic activity abrogating reflux-induced dysbiosis, and mitigating bile acid metabolism and transport, culminating in significant inhibition of EAC through TLR/NF-κB/P53 signaling cascades. At the species level, C-PAC mitigated reflux-induced pathogenic bacteria (Clostridium perfringens, Escherichia coli, and Proteus mirabilis). C-PAC specifically reversed reflux-induced bacterial, inflammatory and immune-implicated proteins and genes including Ccl4, Cd14, Crp, Cxcl1, Il6, Il1β, Lbp, Lcn2, Myd88, Nfkb1, Tlr2 and Tlr4 aligning with changes in human EAC progression, as confirmed through public databases. C-PAC is a safe promising dietary constituent that may be utilized alone or potentially as an adjuvant to current therapies to prevent EAC progression through ameliorating reflux-induced dysbiosis, inflammation and cellular damage.

Abstract 1745: Targeting therapeutic resistance of esophageal adenocarcinoma through modulating the epithelial-to-mesenchymal transition via NFκB-mediated signaling

Esophageal adenocarcinoma (EAC) is the major subtype of esophageal cancer in Westernized countries, characterized by rising incidence and poor prognosis with a five-year survival rate less than 20%. Only 15% of EAC patients have a complete histopathological response to standard chemotherapy, indicating the urgent need to identify mechanisms associated with therapeutic resistance for improved therapeutic efficacy and patient outcomes. Herein, we performed transcriptional profiling utilizing tissues collected from EAC patients prior to treatment initiation. First, EAC patients (n=67) were stratified into 5 therapeutic response groups based on the changes in TNM pre- to post-treatment; second, bioinformatic approaches were utilized to identify molecular changes associated with response to treatment and patient survival. Third, we employed OE19 and OE33 human EAC cell lines to investigate the efficacy of cranberry proanthocyanidins (C-PAC), a promising anti-inflammatory and anti-cancer agent which shows synergistic effects with carboplatin in other cancer types, at mitigating molecular pathways which drive therapeutic resistance. Our therapeutic response data set revealed epithelial-mesenchymal transition (EMT) as a top pathway associated with differential response to therapy and patient survival. Subsequent gene-set enrichment analysis identified that EMT is significantly associated with NFκB and STAT3 signaling pathways, two nodes with documented proinflammatory roles in EAC progression. Deconvolution analysis was conducted further supporting EMT enrichment creates an immune-suppressive tumor microenvironment in EAC patients. Next, EAC cell viability, migration and interrogation of EMT signaling proteins were conducted following treatment with paclitaxel and carboplatin (chemo drugs) alone or in combination with C-PAC. Combination treatment of C-PAC and chemo drugs significantly inhibited EAC cell viability and migration capability, compared to cells treated with chemo drugs alone, with synergistic effects observed in OE33 cells. Moreover, combination treatment also significantly decreased NFκB1 expression and expressions of EMT markers and transcription factors (Snail, MMP-2, MMP-9, and Vimentin) whereas cells treated only with chemo drugs showed minimal modulation. Knockdown experiments of NFκB1 using RNA interference are underway to investigate the relationship between canonical NFκB1 signaling and EMT. Primary cell lines and organoids developed from isolated EAC patient tissues will also be used in the future to validate experimental findings. The results suggest C-PAC may be used as a safe and novel therapeutic strategy to improve chemotherapy efficacy targeting EAC.

Citation Format: Yun Zhang, Katherine M. Weh, Connor L. Howard, Jean-Jack Riethoven, Jennifer L. Clarke, Michelle P. Lee, Kiran H. Lagisetty, Jules Lin, Rishindra M. Reddy, Andrew C. Chang, Amy B. Howell, Laura A. Kresty. Targeting therapeutic resistance of esophageal adenocarcinoma through modulating the epithelial-to-mesenchymal transition via NFκB-mediated signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1745.

Abstract PR001: Mechanisms by which Mito-LND inhibits KRAS mutant lung cancer

Lung cancer remains the most frequently diagnosed cancer and leading cause of cancer mortality in the United States and worldwide. Efficacious targeted options are urgently needed for lung cancer prevention and treatment. Approximately 30% of non-small cell lung cancer cases have KRAS mutations, yet pharmacological targeting has eluded the scientific community due to structural and biochemical properties of the KRAS protein. We recently synthesized Mito-lonidamine (Mito-LND), a mitochondrial targeted analog of lonidamine which inhibits aerobic glycolysis in cancer cells. We identified that Mito-LND induces autophagy, specifically mitophagy, preferentially in KRAS mutant lung adenocarcinoma cells and inhibits lung tumor development and brain metastasis in vivo. The cancer inhibitory mechanisms by which Mito-LND induces mitophagy, including requisite receptors and effects on immune signaling cascades remains unknown. We evaluated FDA-approved cell death inhibitors for autophagy (chloroquine; CQ), mitophagy (cyclosporin A; CsA) and necrosis (ponatinib) in KRAS (H2030 and H2030BrM3) mutant cells using cellular viability assays in combination with Mito-LND. siRNA was utilized to knockdown autophagy/mitophagy receptors (P62, PINK1, NDP52, OPTN and BECN1) in KRAS mutant cells, followed by Mito-LND treatment and viability assessments. Last, KRAS mutant cells were treated with Mito-LND to evaluate transcriptomic changes by RNA sequencing and deconvolution analysis performed to interrogate alterations in immune cell populations. CQ and CsA significantly inhibited Mito-LND induced cell death in H2030BrM3 cells. Interestingly, necrosis inhibition with ponatinib synergistically increased Mito-LND induced cell death in both cell lines. Of the receptors tested (P62, PINK1, OPTN and NDP52), NDP52 in H2030BrM3 cells appears requisite for Mito-LND induced cell death. Following transcriptomic sequencing, we conducted pathway analysis in Metacore on the significantly dysregulated genes (P and FDR<0.05). Mito-LND significantly upregulated heat shock protein signaling, HIF1A transcriptional targets, ER stress and the immune response. Downregulation of cell adhesion was noted in both cell lines, with changes in EMT and WNT signaling noted only in H2030 cells. Gene set enrichment analysis revealed TNFα signaling via NF-κB as the only hallmark significantly enriched by Mito-LND. Deconvolution analysis discerned alterations to T and B cell populations, highlighting a potential role for Mito-LND in modulating adaptive immunity. These results begin to define the cancer inhibitory mechanisms by which Mito-LND induces cancer cell death, including requisite receptors, signaling pathways and immune cell populations in KRAS mutant cells. Future directions include evaluating potential synergy of Mito-LND in combination with additional cell death and KRAS-targeting drugs as well as characterizing autophagy/mitophagy receptors in vivo utilizing chemically induced and genetically driven mouse models of lung carcinogenesis.

Citation Format: Katherine M. Weh, Connor L. Howard, Yun Zhang, Jean-Jack Riethoven, Jennifer L. Clarke, Balaraman Kalyanaraman, Ming You, Laura A. Kresty. Mechanisms by which Mito-LND inhibits KRAS mutant lung cancer. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr PR001.

Characterizing isoform switching events in esophageal adenocarcinoma

Isoform switching events with predicted functional consequences are common in many cancers, but characterization of switching events in esophageal adenocarcinoma (EAC) is lacking. Next-generation sequencing was used to detect levels of RNA transcripts and identify specific isoforms in treatment-naïve esophageal tissues ranging from premalignant Barrett’s esophagus (BE), BE with low- or high-grade dysplasia (BE.LGD, BE.HGD), and EAC. Samples were stratified by histopathology and TP53 mutation status, identifying significant isoform switching events with predicted functional consequences. Comparing BE.LGD with BE.HGD, a histopathology linked to cancer progression, isoform switching events were identified in 75 genes including KRAS, RNF128, and WRAP53. Stratification based on TP53 status increased the number of significant isoform switches to 135, suggesting switching events affect cellular functions based on TP53 mutation and tissue histopathology. Analysis of isoforms agnostic, exclusive, and shared with mutant TP53 revealed unique signatures including demethylation, lipid and retinoic acid metabolism, and glucuronidation, respectively. Nearly half of isoform switching events were identified without significant gene-level expression changes. Importantly, two TP53-interacting isoforms, RNF128 and WRAP53, were significantly linked to patient survival. Thus, analysis of isoform switching events may provide new insight for the identification of prognostic markers and inform new potential therapeutic targets for EAC.

Abstract 5741: Characterizing isoform switching events in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC), the major subtype of esophageal cancer in the US, is characterized by increasing incidence rates and high mortality due to ineffective screening, late-stage diagnosis, and poor treatment efficacy. The only known precursor to EAC is Barrett’s Esophagus (BE), but the precise mechanisms and molecular events leading to disease progression are still being unraveled. In recent years, analysis of TCGA data revealed that isoform switching events with predicted functional consequences are common in many cancers, but the characterization of switching events in esophageal adenocarcinoma (EAC) is lacking. Next-generation sequencing was utilized to detect levels of RNA transcripts and specific isoforms in 66 treatment naïve esophageal tissues from 41 patients. Tissues ranged from premalignant Barrett’s esophagus (BE), BE with low or high-grade dysplasia (LGD or HGD) to EAC. Samples were stratified by histopathology, p53 mutation status, and significant isoform switching events with predicted functional consequences, followed by enrichment analysis. Barrett’s with high-grade dysplasia increased risk for EAC progression. Comparing BE with LGD and BE with HGD, isoform switching events were identified in 75 genes including KRAS, APC, RNF-128 and WRAP53. Stratification based on p53 status increased the number of significant isoform switches to 135 suggesting switching events impact cellular functions based on tissue histopathology, as well as p53 status. Analysis of isoforms agnostic to mutant p53, exclusive to mutant p53, and shared between the two groups revealed unique signatures including demethylation, lipid and retinoic acid metabolism, and glucuronidation, respectively. About 25% of isoform switching events were identified without significant alteration of gene-level expression. Importantly, two p53-interacting isoforms, RNF128 and WRAP53, were significantly linked to patient survival. Analysis of global isoform switching consequences and alternative splicing events also revealed significant changes in the fraction of coding transcripts, complete open-reading-frames, signal peptides, alternative 5’ donor sites, and alternative transcription start sites. Thus, analysis of isoform switching events may provide new insight for the identification of prognostic markers and inform new potential therapeutic targets for EAC treatment or prevention.

Citation Format: Yun Zhang, Katherine M. Weh, Connor L. Howard, Jean-Jack Riethoven, Jennifer L. Clarke, Kiran H. Lagisetty, Jules Lin, Rishindra M. Reddy, Andrew C. Chang, David G. Beer, Laura A. Kresty. Characterizing isoform switching events in esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5741.

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

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.

Abstract 2593: Racially diverse primary esophageal cell cultures for evaluating mitigation of bile-induced injury

Persistent and symptomatic reflux of gastric and duodenal contents, known as gastroesophageal reflux disease (GERD), is the strongest risk factor for EAC development. GERD and esophagitis occur at similar rates among Blacks and Caucasians; yet, progression to EAC is significantly elevated among Caucasians. Unique protective factors in the epithelium of Blacks may contribute to this disparity. Our research team recently reported that the detoxification enzyme GSTT2 is higher in the esophageal squamous epithelium of Blacks compared to Caucasians with potential linkages to previously identified genomic variants in the GSTT2 locus (a 37 kb deletion and a 17 bp promoter duplication among Caucasians). Thus, the current study seeks to evaluate whether primary esophageal cell cultures isolated from Black or Caucasian cohorts can serve as discerning and relevant model systems to investigate risk factors linked to EAC progression, assess efficacy of mitigating agents and differential responses linked to race. We have shown that cranberry proanthocyanidins (C-PAC) mitigate DNA damage associated with reflux through upregulation of GSTT2 in a rat surgical model of reflux-induced EAC, but whether effects are recapitulated in humans or differentially based on race remains unknown. Herein we isolated normal primary esophageal epithelial cells from Black and Caucasian patients and assessed GSTT2 genotype, GSTT2 protein levels and cellular viability following exposure of the cultures to a bile acid cocktail (BAC) [0.2mM] with and without C-PAC [50µg/ml] treatment. Constitutive levels of GSTT2 were 1.7-fold higher in Blacks than Caucasians, with 71% of Blacks identified as high expressors compared to 33% of Caucasians. Pretreatment (48h) of primary cultures with C-PAC induced GSTT2 levels in all but one Black-derived culture which already expressed high basal levels. GSTT2 induction in normal epithelial cultures by C-PAC was greatest in cells with constitutively low GSTT2 expression; however, upon BAC challenge C-PAC effectively mitigated BAC-induced reductions in GSTT2 levels and subsequent loss of normal cell viability regardless of basal GSTT2 expression or race. C-PAC treatment pre- plus post-BAC imparted no additional benefit over pretreatment alone in preserving viability but did further increase GSTT2 levels. Next steps include expanding our panel of primary cultures and conducting nano LC-MS/MS proteomic profiling of Black and Caucasian-derived cultures treated with vehicle, BAC, C-PAC and BAC + C-PAC, with stratification based on GSTT2 basal expression. Taken together these data support that C-PAC may be used as an efficacious non-toxic agent serving to promote epithelial fitness and resiliency against the biologic and molecular sequelae linked bile acid-induced esophageal injury and progression to EAC.

Citation Format: Katherine M. Weh, Danielle K. Turgeon, Amy Howell, Laura A. Kresty. Racially diverse primary esophageal cell cultures for evaluating mitigation of bile-induced injury [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2593.

Immune determinants of Barrett's progression to esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) develops from Barrett’s esophagus (BE), a chronic inflammatory state that can progress through a series of transformative dysplastic states before tumor development. While molecular and genetic changes of EAC tumors have been studied, immune microenvironment changes during Barrett’s progression to EAC remain poorly understood. In this study, we identify potential immunologic changes that can occur during BE-to-EAC progression. RNA sequencing (RNA-Seq) analysis on tissue samples from EAC patients undergoing surgical resection demonstrated that a subset of chemokines and cytokines, most notably IL6 and CXCL8, increased during BE progression to EAC. xCell deconvolution analysis investigating immune cell population changes demonstrated that the largest changes in expression during BE progression occurred in M2 macrophages, pro–B cells, and eosinophils. Multiplex immunohistochemical staining of tissue microarrays showed increased immune cell populations during Barrett’s progression to high-grade dysplasia. In contrast, EAC tumor sections were relatively immune poor, with a rise in PD-L1 expression and loss of CD8⁺ T cells. These data demonstrate that the EAC microenvironment is characterized by poor cytotoxic effector cell infiltration and increased immune inhibitory signaling. These findings suggest an immunosuppressive microenvironment, highlighting the need for further studies to explore immune modulatory therapy in EAC.

Disparities in Head and Neck Cancer: A Case for Chemoprevention with Vitamin D

Blacks experience disproportionate head and neck cancer (HNC) recurrence and mortality compared to Whites. Overall, vitamin D status is inversely associated to HNC pointing to a potential protective linkage. Although hypovitaminosis D in Blacks is well documented it has not been investigated in Black HNC patients. Thus, we conducted a prospective pilot study accessing vitamin D status in newly diagnosed HNC patients stratified by race and conducted in vitro studies to investigate mechanisms associated with potential cancer inhibitory effects of vitamin D. Outcome measures included circulating levels of vitamin D, related nutrients, and risk factor characterization as well as dietary and supplemental estimates. Vitamin D-based in vitro assays utilized proteome and microRNA (miR) profiling. Nineteen patients were enrolled, mean circulating vitamin D levels were significantly reduced in Black compared to White HNC patients, 27.3 and 20.0 ng/mL, respectively. Whites also supplemented vitamin D more frequently than Blacks who had non-significantly higher vitamin D from dietary sources. Vitamin D treatment of HNC cell lines revealed five significantly altered miRs regulating genes targeting multiple pathways in cancer based on enrichment analysis (i.e., negative regulation of cell proliferation, angiogenesis, chemokine, MAPK, and WNT signaling). Vitamin D further altered proteins involved in cancer progression, metastasis and survival supporting a potential role for vitamin D in targeted cancer prevention.

Abstract 6588: Omics integration provides insight into esophageal cancer inhibitory mechanisms of a cranberry extract

Our laboratory studies chemoprevention of esophageal adenocarcinoma (EAC) through utilization of the rat esophagogastroduodenal anastomosis (EGDA) surgical model of reflux-induced EAC. Specifically, we evaluated mechanisms by which cranberry proanthocyanidins (C-PAC) inhibit reflux-induced EAC by utilizing multi-omics integrative approaches employing multiple program platforms. Herein, we investigated whether pathway-based integration could be used to examine cross-talk between genes, metabolites and the microbial profiles. For this analysis, we utilized transcriptomic and untargeted metabolomic data from rat esophagi of animals that received water or C-PAC in the drinking water alone or combined with reflux inducing EGDA surgery. Additionally, we isolated DNA from fecal pellets and performed 16S rRNA sequencing to assess gut microbiome composition and functionality. Each omics dataset was analyzed for significant pathway enrichment and network generation using Metacore, DAVID and Metabolync. PICRUSt was utilized to predict microbiota functionality. Analysis of transcriptomic and metabolomic data suggest that EGDA upregulates inflammatory, NF-kB, DNA damage, cell cycle and immune function pathways as well as metabolic pathways related to eicosanoids, amino acids and primary and secondary bile acids, while C-PAC mitigates these alterations. Preliminary microbiome data analysis also suggests that bacteria related to inflammation, metabolite transport and DNA damage are increased in abundance in EGDA, with a decrease in abundance following C-PAC treatment. Analysis of omics datasets can provide insightful relationships into the cross-talk between different processes regulated by transcription, metabolism and the microbiome. Single dataset and integrative analysis showed similarities in altered pathways for vehicle and C-PAC treated animals in the context of reflux. Integration is limited by the infancy of multi-omics analysis programs, as well as the limited amount of research involving prediction of bacterial function and integration of microbiome data with other omics datasets. Further research and development of these omics programs is needed to determine accuracy of predicted results as well as continued investigation of identified pathways.

Citation Format: Katherine M. Weh, Connor L. Howard, Bridget A. Tripp, Jennifer L. Clarke, Amy B. Howell, Laura A. Kresty. Omics integration provides insight into esophageal cancer inhibitory mechanisms of a cranberry extract [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6588.

Circular RNA circHIPK3 modulates autophagy via MIR124-3p-STAT3-PRKAA/AMPKα signaling in STK11 mutant lung cancer

The role of circular RNA in cancer is emerging. A newly reported circular RNA HIPK3 (circHIPK3) is critical in cell proliferation of various cancer types, although its role in non-small cell lung cancer (NSCLC), has yet to be elucidated. Our results provided evidence that silencing of circHIPK3 significantly impaired cell proliferation, migration, invasion and induced macroautophagy/autophagy. Mechanistically, we uncovered that autophagy was induced upon loss of circHIPK3 via the MIR124-3p-STAT3-PRKAA/AMPKa axis in STK11 mutant lung cancer cell lines (A549 and H838). STAT3 abrogation as well as transfection with a MIR124-3p mimic, recapitulated the induction of autophagy. We also demonstrated antagonistic regulation on autophagy between circHIPK3 and linear HIPK3 (linHIPK3). We therefore propose that the ratio between circHIPK3 and linHIPK3 (C:L ratio) may reflect autophagy levels in cancer cells. We observed that a high C:L ratio (>0.49) was an indicator of poor survival, especially in advanced-stage NSCLC patients. These results support that circHIPK3 is a key autophagy regulator in a subset of lung cancer and has potential clinical use as a prognostic factor. The circular RNA HIPK3 (circHIPK3) functions as an oncogene and autophagy regulator may potential use as a prognostic marker and therapeutic target in lung cancer.Abbreviations 3-MA: 3-methyladenine; AMPK: AMP-activated protein kinase; ATG7: autophagy related 7; Baf-A: bafilomycin A1; BECN1: beclin 1; circHIPK3: circular HIPK3; CQ: chloroquine; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HIPK3: homeodomain interacting protein kinase 3; IL6R: interleukin 6 receptor; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; NSCLC: non-small cell lung cancer; RFP: red fluorescent protein; RPS6KB1/S6K: ribosomal protein S6 kinase B1; SQSTM1/p62: sequestosome 1; STAT3: signal transducer and activator of transcription 3; STK11: serine/threonine kinase 11.

Circular RNA circHIPK3 modulates autophagy via MIR124-3p-STAT3-PRKAA/AMPKα signaling in STK11 mutant lung cancer

The role of circular RNA in cancer is emerging. A newly reported circular RNA HIPK3 (circHIPK3) is critical in cell proliferation of various cancer types, although its role in non-small cell lung cancer (NSCLC), has yet to be elucidated. Our results provided evidence that silencing of circHIPK3 significantly impaired cell proliferation, migration, invasion and induced macroautophagy/autophagy. Mechanistically, we uncovered that autophagy was induced upon loss of circHIPK3 via the MIR124-3p-STAT3-PRKAA/AMPKa axis in STK11 mutant lung cancer cell lines (A549 and H838). STAT3 abrogation as well as transfection with a MIR124-3p mimic, recapitulated the induction of autophagy. We also demonstrated antagonistic regulation on autophagy between circHIPK3 and linear HIPK3 (linHIPK3). We therefore propose that the ratio between circHIPK3 and linHIPK3 (C:L ratio) may reflect autophagy levels in cancer cells. We observed that a high C:L ratio (>0.49) was an indicator of poor survival, especially in advanced-stage NSCLC patients. These results support that circHIPK3 is a key autophagy regulator in a subset of lung cancer and has potential clinical use as a prognostic factor. The circular RNA HIPK3 (circHIPK3) functions as an oncogene and autophagy regulator may potential use as a prognostic marker and therapeutic target in lung cancer.Abbreviations 3-MA: 3-methyladenine; AMPK: AMP-activated protein kinase; ATG7: autophagy related 7; Baf-A: bafilomycin A₁; BECN1: beclin 1; circHIPK3: circular HIPK3; CQ: chloroquine; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HIPK3: homeodomain interacting protein kinase 3; IL6R: interleukin 6 receptor; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; NSCLC: non-small cell lung cancer; RFP: red fluorescent protein; RPS6KB1/S6K: ribosomal protein S6 kinase B1; SQSTM1/p62: sequestosome 1; STAT3: signal transducer and activator of transcription 3; STK11: serine/threonine kinase 11.

Abstract 5077: Proteomic profiling reveals chemopreventive targets in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) is characterized by rising incidence rates and high mortality due to late stage diagnosis and a lack of efficacious options for prevention and treatment. While reasons for the rapid increase in EAC are being unraveled, persistent, symptomatic reflux of gastric and duodenal contents, known as gastroesophageal reflux disease is considered the strongest risk factor. Our laboratory utilizes a rat surgical model of reflux-induced EAC to evaluate mechanisms by which cranberry proanthocyanidins (C-PAC) delivered in the drinking water inhibit reflux-induced EAC. Findings show that C-PAC (690ug/rat/day) inhibits EAC formation by 83% at 40 weeks of study and mechanisms of inhibition are under investigation. We utilized nano LC-MS/MS proteomic profiling to identify proteins that were dysregulated due to reflux-induced EAC and reversed with C-PAC treatment. Proteomic profiling revealed that C-PAC treatment restored 63 proteins dysregulated in the context of reflux. EIF3F, PSMD2 and ACTR2 were the top proteins up-regulated by reflux; whereas, top markers restored by C-PAC included GSTT2, OGN and PCMT1. Metacore integrated software showed top pathways up-regulated by reflux and down-regulated C-PAC included Translation_regulation of translation initiation (EIF-linked), Immune response and Regulation of telomere length. Conversely, C-PAC treatment upregulated the glutathione metabolism pathway which is consistent with GSTT2 restoration. Disease enrichment analysis revealed multiple gastrointestinal tract diseases linked to reflux, which C-PAC down regulated supporting that proteomic profiling may inform other potential disease targets for C-PAC. Finally, beyond the 63 reflux-driven proteins C-PAC reversed, we considered proteins, pathways and processes which could not be reversed by C-PAC (n=269). As an example, Process networks upregulated by reflux (not reversed by C-PAC) included Translation initiation (RPL-linked), Elongation, mRNA processing, G2-M and S-phase of the cell cycle. Thus, proteomics profiling may inform the development of complementary preventive combinations for improved cancer inhibitory efficacy, especially for a cancer like EAC, with high mutational burden. Western blot analysis of several markers in the rat esophagus including GSTT2 and COX2 support the data obtained through proteomic profiling. Future directions include interrogating specific pathways that are highly modulated by reflux-induced EAC and restored by C-PAC including DNA damage, repair and extracellular matrix and adhesion. Last, proteomic profiling has also allowed for identification of post-translational modifications which may provide insight into regulation of key dysregulated proteins.

Citation Format: Katherine M. Weh, Connor L. Howard, Amy B. Howell, Jennifer L. Clarke, Laura A. Kresty. Proteomic profiling reveals chemopreventive targets in esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5077.

Constitutively Higher Level of GSTT2 in Esophageal Tissues From African Americans Protects Cells Against DNA Damage

BACKGROUND & AIMS

African American and European American individuals have a similar prevalence of gastroesophageal reflux disease (GERD), yet esophageal adenocarcinoma (EAC) disproportionately affects European American individuals. We investigated whether the esophageal squamous mucosa of African American individuals has features that protect against GERD-induced damage, compared with European American individuals.

METHODS

We performed transcriptional profile analysis of esophageal squamous mucosa tissues from 20 African American and 20 European American individuals (24 with no disease and 16 with Barrett's esophagus and/or EAC). We confirmed our findings in a cohort of 56 patients and analyzed DNA samples from patients to identify associated variants. Observations were validated using matched genomic sequence and expression data from lymphoblasts from the 1000 Genomes Project. A panel of esophageal samples from African American and European American subjects was used to confirm allele-related differences in protein levels. The esophageal squamous-derived cell line Het-1A and a rat esophagogastroduodenal anastomosis model for reflux-generated esophageal damage were used to investigate the effects of the DNA-damaging agent cumene-hydroperoxide (cum-OOH) and a chemopreventive cranberry proanthocyanidin (C-PAC) extract, respectively, on levels of protein and messenger RNA (mRNA).

RESULTS

We found significantly higher levels of glutathione S-transferase theta 2 (GSTT2) mRNA in squamous mucosa from African American compared with European American individuals and associated these with variants within the GSTT2 locus in African American individuals. We confirmed that 2 previously identified genomic variants at the GSTT2 locus, a 37-kb deletion and a 17-bp promoter duplication, reduce expression of GSTT2 in tissues from European American individuals. The nonduplicated 17-bp promoter was more common in tissue samples from populations of African descendant. GSTT2 protected Het-1A esophageal squamous cells from cum-OOH-induced DNA damage. Addition of C-PAC increased GSTT2 expression in Het-1A cells incubated with cum-OOH and in rats with reflux-induced esophageal damage. C-PAC also reduced levels of DNA damage in reflux-exposed rat esophagi, as observed by reduced levels of phospho-H2A histone family member X.

CONCLUSIONS

We found GSTT2 to protect esophageal squamous cells against DNA damage from genotoxic stress and that GSTT2 expression can be induced by C-PAC. Increased levels of GSTT2 in esophageal tissues of African American individuals might protect them from GERD-induced damage and contribute to the low incidence of EAC in this population.

A phase I pilot study evaluating the beneficial effects of black raspberries in patients with Barrett's esophagus

Black raspberries inhibit a broad range of cancers in preclinical models which has led to clinical evaluations targeting premalignant lesions of the colon, oral cavity and esophagus. A phase I pilot study was conducted in twenty Barrett's esophagus (BE) patients to investigate the effect of lyophilized black raspberries (LBR) on urinary metabolites and markers of lipid peroxidation, DNA damage and tissue markers of cellular proliferation, detoxification, and inflammation. Surveys, biopsies, blood and urine samples were collected before and after 6 months of LBR treatment (32 or 45 g). LBR significantly reduced urinary excretion of 8-epi-prostaglandin F2α, a marker of lipid peroxidation linked to oxidative stress and free radical damage. Urinary levels of the ellagitannin metabolites, urolithin A-glucuronide, urolithin A-sulfate and dimethylellagic acid glucuronide were significantly increased following 12 and 26 weeks of LBR consumption and may prove useful as indicators of compliance in future clinical studies. Immunohistochemical staining of BE biopsies following LBR treatment showed significant increases in mean GST-pi levels, with 55.6% of subjects responding favorably. In summary, LBR significantly decreased urinary lipid peroxidation levels and significantly increased GST-pi, a marker of detoxification, in BE epithelium. Still, LBR may need to be formulated differently, administered at higher concentrations or multiple times a day to increase efficacy.

Abstract 279: Cranberry proanthocyanidins mitigate reflux-induced transporter dysregulation in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) incidence rates have increased sharply (>500%) throughout the Westernized world since the 1980s, despite the widespread use of endoscopy and anti-reflux medications. Reasons for the rapid increase in EAC are still being unraveled; however, persistent, symptomatic reflux of gastric and duodenal contents, known as gastroesophageal disease (GERD), is considered the strongest risk factor. Our laboratory utilizes the rat esophagogastroduodenal anastomosis (EGDA) surgical model of reflux-induced EAC to evaluate mechanisms by which cranberry proanthocyanidins (C-PAC) delivered in the drinking water inhibit reflux-induced EAC. Findings show that C-PAC inhibits EAC formation by 83% with concomitant restoration of the gut microbial profile and significant reduction of primary and secondary bile acid metabolites in the esophagus of animals with reflux-inducing surgery, but through unknown mechanisms. Herein, we investigated whether transporters, important in bile acid transport, buffering capacity, excretion, and even resistance to anticancer agents, were restored by C-PAC in the context of reflux. Additionally, we utilized a publicly available GEO dataset (GSE37203) to assess transporter expression levels in patients with metaplastic Barrett's esophagus (BE) versus those with high grade dysplasia (HGD) or EAC for translational relevance. Methods included esophageal RNA isolation, transcriptome sequencing using the Illumina HiSeq platform, followed by validation utilizing the PrimePCR Drug Transporter array plate and database mining. Results show significant changes in solute carriers (SLC), ATP-binding cassette (ABC) and aquaporin transporters in the rat reflux-induced model for EAC with C-PAC mitigating alterations. EGDA altered one or more members in 71% of the SLC families with frequent changes observed in SLC25, SLC4, SLC35, SLC2 and SLC6. C-PAC favorably impacted >40% of the EGDA-induced SLC changes. A number of ABC transporters involved in glutathione transport and also implicated in drug resistance were altered by EGDA including Abcc1, Abcc3, Abcc4, Abcc5 and Abcg2 and C-PAC mitigated these changes. Aquaporins, Aqp3 and Aqp4, were significantly modulated in EGDA and restored with C-PAC. Significant differences in ABCC9, ABCC10, AQP6 and AQP9, in addition to several members of the SLC25, SLC4, SLC35, SLC2 and SLC6 families, were observed in patients with HGD/EAC compared to those with BE metaplasia. Therefore, altered expression of transporters following reflux-inducing surgery or GERD is likely a defensive mechanism by which cells attempt to adapt or protect from injurious bile acid exposure. Further research is warranted to investigate agents that restore normal transporter function, which may serve to concomitantly improve epithelial barrier function and mucosal integrity in the context of esophageal cancer progression.

Citation Format: Katherine M. Weh, Bridget A. Tripp, Jennifer L. Clarke, Amy B. Howell, Jules Lin, David G. Beer, Andrew C. Chang, Laura A. Kresty. Cranberry proanthocyanidins mitigate reflux-induced transporter dysregulation in esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 279.

The role of nutrition in influencing mechanisms involved in environmentally mediated diseases

Human exposure to environmental contaminants such as persistent chlorinated organics, heavy metals, pesticides, phthalates, flame retardants, electronic waste and airborne pollutants around the world, and especially in Southeast Asian regions, are significant and require urgent attention. Given this widespread contamination and abundance of such toxins as persistent organic pollutants (POPs) in the ecosystem, it is unlikely that remediation alone will be sufficient to address the health impacts associated with this exposure. Furthermore, we must assume that the impact on health of some of these contaminants results in populations with extraordinary vulnerabilities to disease risks. Further exacerbating risk; infectious diseases, poverty and malnutrition are common in the Southeast Asian regions of the world. Thus, exploring preventive measures of environmental exposure and disease risk through new paradigms of environmental toxicology, optimal and/or healthful nutrition and health is essential. For example, folic acid supplementation can lower blood arsenic levels, and plant-derived bioactive nutrients can lower cardiovascular and cancer risks linked to pollutant exposure. Data also indicate that diets enriched with bioactive food components such as polyphenols and omega-3 polyunsaturated fatty acids can prevent or decrease toxicant-induced inflammation. Thus, consuming healthy diets that exhibit high levels of antioxidant and anti-inflammatory properties, is a meaningful way to reduce the vulnerability to non-communicable diseases linked to environmental toxic insults. This nutritional paradigm in environmental toxicology requires further study in order to improve our understanding of the relationship between nutrition or other lifestyle modifications and toxicant-induced diseases. Understanding mechanistic relationships between nutritional modulation of environmental toxicants and susceptibility to disease development are important for both cumulative risk assessment and the design and implementation of future public health programs and behavioral interventions.

Abstract 5250: Cranberry proanthocyanidins reverse microbial dysbiosis and inhibit bile acid metabolism in association with esophageal cancer prevention

Our laboratory has been investigating the cancer inhibitory potential of cranberry proanthocyanidins (C-PAC) against esophageal adenocarcinoma (EAC), a cancer characterized by rapidly rising incident rates and poor survival (18% 5-year survival rate for all stages combined). Utilizing a panel of validated human esophageal cancer cell lines and OE19 xenograft bearing mice, our laboratory reported that C-PAC activates autophagic cell machinery leading to caspase-independent cancer cell death, yet linked to bile acid sensitivity. Reflux of bile and stomach acid into the lower esophagus is considered the major risk factor for progression to EAC. Building on our initial research, we next investigated mechanisms by which C-PAC inhibits reflux-induced EAC with a focus on gut microbiome alterations and modulation of bile acid metabolites. Bile acids undergo secondary metabolism in the intestinal tract, but have not been evaluated in this context. We utilized the rat surgical esophagogastroduodenal anastomosis (EGDA) model for reflux-induced EAC. EGDA+ and non-surgical Sprague Dawley rats were treated with water or C-PAC (650 µg/rat/day) for 25 or 40 weeks and assessed for cancer progression via extensive histopathological characterization. Additionally, at 40 weeks, fecal microbiome profiling was investigated and metabolic profiling conducted on esophageal, liver and fecal samples. Methods included 16s rRNA sequencing of rat fecal DNA, paired end sequencing on Illumina MiSeq and data analysis using Qiime and the R packages phyloseq, and edgeR to assess C-PAC-induced microbiome changes. For metabolite profiling homogenized esophagi, liver and fecal samples were extracted in methanol and characterized by Reverse Phase Ultra high Performance Liquid Chromatography-Tandem Mass Spectrometry RP/UPLC-MS/MS, followed by metabolite identification based on Metabolon’s library of authenticated standards. Study results support that C-PAC significantly inhibits the formation of EAC with concomitant restoration of the gut microbial profile, i.e., the bacterial profile shifted toward increased favorable Gram+ Firmicutes and away from inflammatory-linked Gram negative Bacteroidetes. In addition, C-PAC treatment significantly reduced primary and secondary bile acid metabolite levels in the esophagus of reflux/EGDA+ rats. Other metabolites significantly reduced by C-PAC included a number of pro-inflammatory Eicosanoids. In summary, these results support that (1) reflux-induced microbial impairment correlates with the stimulation of bile acid metabolism, and (2) C-PAC mitigates reflux-induced inflammation and injury in the esophagus in association with EAC inhibition. Future research with C-PAC in patients with gastroesophageal reflux disease should include assessments of bile acid metabolites and bacterial profiles as potential cancer-inhibitory mechanisms.

Citation Format: Katherine M. Weh, Nita H. Salzman, Amy B. Howell, Jennifer L. Clarke, Bridget A. Tripp, Laura A. Kresty. Cranberry proanthocyanidins reverse microbial dysbiosis and inhibit bile acid metabolism in association with esophageal cancer prevention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5250. doi:10.1158/1538-7445.AM2017-5250

Cranberry proanthocyanidins inhibit esophageal adenocarcinoma in vitro and in vivo through pleiotropic cell death induction and PI3K/AKT/mTOR inactivation

Cranberries are rich in bioactive constituents known to improve urinary tract health and more recent evidence supports cranberries possess cancer inhibitory properties. However, mechanisms of cancer inhibition by cranberries remain to be elucidated, particularly in vivo. Properties of a purified cranberry-derived proanthocyanidin extract (C-PAC) were investigated utilizing acid-sensitive and acid-resistant human esophageal adenocarcinoma (EAC) cell lines and esophageal tumor xenografts in athymic NU/NU mice. C-PAC induced caspase-independent cell death mainly via autophagy and low levels of apoptosis in acid-sensitive JHAD1 and OE33 cells, but resulted in cellular necrosis in acid-resistant OE19 cells. Similarly, C-PAC induced necrosis in JHAD1 cells pushed to acid-resistance via repeated exposures to an acidified bile cocktail. C-PAC associated cell death involved PI3K/AKT/mTOR inactivation, pro-apoptotic protein induction (BAX, BAK1, deamidated BCL-xL, Cytochrome C, PARP), modulation of MAPKs (P-P38/P-JNK) and G_2-M cell cycle arrest in vitro. Importantly, oral delivery of C-PAC significantly inhibited OE19 tumor xenograft growth via modulation of AKT/mTOR/MAPK signaling and induction of the autophagic form of LC3B supporting in vivo efficacy against EAC for the first time. C-PAC is a potent inducer of EAC cell death and is efficacious in vivo at non-toxic behaviorally achievable concentrations, holding promise for preventive or therapeutic interventions in cohorts at increased risk for EAC, a rapidly rising and extremely deadly malignancy.

Analyzing spatial correlations in tissue using angle-resolved low coherence interferometry measurements guided by co-located optical coherence tomography

Angle-resolved low coherence interferometry (a/LCI) is an optical technique used to measure nuclear morphology in situ. However, a/LCI is not an imaging modality and can produce ambiguous results when the measurements are not properly oriented to the tissue architecture. Here we present a 2D a/LCI system which incorporates optical coherence tomography imaging to guide the measurements. System design and characterization are presented, along with example cases which demonstrate the utility of the combined measurements. In addition, future development and applications of this dual modality approach are discussed.

Cranberry proanthocyanidins modulate reactive oxygen species in Barrett's and esophageal adenocarcinoma cell lines

BACKGROUND

We recently reported that a cranberry proanthocyanidin rich extract (C-PAC) induces autophagic cell death in apoptotic resistant esophageal adenocarcinoma (EAC) cells and necrosis in autophagy resistant cells. EAC is characterized by high morbidity and mortality rates supporting development of improved preventive interventions.

OBJECTIVE

The current investigation sought to investigate the role of reactive oxygen species (ROS) in the context of C-PAC induced cell death.

METHODS

A panel of human esophageal cell lines of EAC or BE (Barrett's esophagus) origin were treated with C-PAC and assessed for ROS modulation using CellROX^® Green reagent and the Amplex Red assay to specifically measure hydrogen peroxide levels.

RESULTS

C-PAC significantly increased ROS levels in EAC cells, but significantly reduced ROS levels in CP-C BE cells. Increased hydrogen peroxide levels were also detected in C-PAC treated EAC cells and supernatant; however, hydrogen peroxide levels were significantly increased in medium alone, without cells, suggesting that C-PAC interferes or directly acts on the substrate. Hydrogen peroxide levels did not change in C-PAC treated CP-C BE cells.

CONCLUSION

These experiments provide additional mechanistic insight regarding C-PAC induced cancer cell death through modulation of ROS. Additional research is warranted to identify specific ROS species associated with C-PAC exposure.

Black raspberries in cancer clinical trials: Past, present and future

BACKGROUND

Black raspberries (BRB) inhibit a broad range of cancers in preclinical models, including in vivo models of oral, esophageal, colon, breast and skin cancer. Promising preclinical results have led to clinical evaluations in cancer patients or patients at increased risk for cancer development.

OBJECTIVE

To summarize clinical investigations targeting cancer or precancerous lesions with BRB and discuss future directions.

METHODS

A thorough literature search was conducted through December 1, 2015 to identify all published studies evaluating BRB in cancer focused clinical trials.

RESULTS

Research investigating BRB in clinical settings report positive effects on preneoplastic lesions or cancers of the oral cavity, esophagus and colon. BRB treatment resulted in: histologic regression of oral intraepithelial neoplasia associated with improved histologic grade and significantly reduced loss of heterozygosity at tumor suppressor gene loci, modulated genes linked to RNA processing and growth factor recycling; in the colon, BRB inhibited FAP-associated polyp progression, demethylated tumor suppressor genes and improved plasma cytokine profiles; in Barrett's patients, BRB consumption increased tissue levels of GST-pi and decreased 8-isoprostane, a marker of lipid peroxidation/oxidative stress.

CONCLUSIONS

The precise dose, duration and optimum mode of BRB delivery for cancer inhibition remains to be fully elucidated. Common themes across studies support that BRB are anti-proliferative, anti- inflammatory, reduce oxidative stress and restore tumor suppressive activity. Future directions are included in the conclusions section.

Expression, modulation, and clinical correlates of the autophagy protein Beclin-1 in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) is characterized by rapidly increasing incidence and mortality rates and poor survival. Efficacious preventive and treatment options are urgently needed. An increasing number of pharmacologic agents targeting cancer cell death via autophagy mechanisms are being evaluated in hopes of circumventing apoptotic and therapeutic resistance. We report for the first time, loss of Beclin-1, a key mediator of autophagy, was significantly linked to prognostic factors in EAC. Specifically, Beclin-1 expression loss occurred in 49.0% of EAC patients versus 4.8% of controls. There was a significant inverse correlation between loss of Beclin-1 with histologic grade and tumor stage supporting a tumor suppressive role for Beclin-1. Autophagy modulation linked to cell death was examined in EAC cell lines following treatment with a proanthocyanidin-rich cranberry extract, C-PAC, and the commonly used autophagy inducer, rapamycin. C-PAC induced Beclin-1-independent autophagy in EAC cells characterized by reduced phosphorylation at serine 15 and 93, and significant cell death induction. In contrast, rapamycin-induced autophagy resulted in concomitant, increases in total Beclin-1 levels as well as Beclin-1-phosphorylation in a cell line specific manner, leading to long-term cell survival. Furthermore, autophagic LC3-II was induced by C-PAC following siRNA suppression of Beclin-1 in EAC cells. Together these data support a prognostic role of Beclin-1 in EAC with evidence that Beclin-dependent autophagy induction is agent specific. Future studies are necessary to fully interrogate the role autophagy plays in the progression of normal tissue to EAC and how specific agents targeting autophagic mechanisms can be efficaciously applied for cancer prevention or treatment. © 2015 Wiley Periodicals, Inc.

Upper esophageal and pharyngeal cancers

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on laryngopharyngeal reflux as a risk factor for laryngeal cancer; the role of pepsin in laryngopharyngeal neoplasia; natural fruit and vegetable compounds for the prevention and treatment of pharyngeal and esophageal cancers; and evaluation of cranberry constituents as inhibitors of esophageal adenocarcinoma utilizing in vitro assay and in vivo models.

Diet and esophageal disease

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on macronutrients, dietary patterns, and risk of adenocarcinoma in Barrett's esophagus; micronutrients, trace elements, and risk of Barrett's esophagus and esophageal adenocarcinoma; the role of mate consumption in the development of squamous cell carcinoma; the relationship between energy excess and development of esophageal adenocarcinoma; and the nutritional management of the esophageal cancer patient.

Abstract 669: Disparities in head and neck cancer: A case for chemoprevention with vitamin D

Worldwide head and neck cancer (HNC) is the sixth most frequently diagnosed cancer in men and is associated with significant morbidity, mortality and economic loss. African Americans (AA) experience significantly more HNC compared to Caucasian Americans (CA) and they have markedly reduced 5-year survival rates, 40% compared to 61% among CA. AA bear a disproportionate burden of HNC for reasons that are incompletely understood, but likely due to the complex interplay of environmental, genetic and health care access issues. An inverse association for vitamin (vit) D status and HNC cancer has been reported and hypovitaminosis D in AA is well documented; yet, vit D status has not been assessed in HNC patients stratified by race. Thus, objective of this prospective pilot study is to access vit D status in newly diagnosed AA and CA HNC patients by measuring the circulating metabolite of vit D, vit-D 25-OH and by assessing dietary levels utilizing the Block vit D/Calcium screener. Circulating calcium, parathyroid, and 1,25-Dihydroxy vit D are also being measured. In addition, to improve our understanding of mechanisms associated with the potential cancer protective effects of vit D in the context of HNC two HNC cell lines were treated with 2 µM cholecalciferol for 6 hours and protein harvested for proteome profiling. To date, 18 HNC patients have been evaluated, 8 AA and 10 CA. Mean circulating vit D 25-OH levels were 27.3 (+ 9.9) and 20.0 (+ 5.9) ng/mL in CA and AA, respectively supporting that vit D levels are suppressed to a greater extent in AA compared to CA HNC patients, even in sunny Florida. Dietary vit D estimates were non-significantly higher in AA HNC patients compared to CA who had higher total vit D levels, supporting differences in metabolism or potentially supplement use. None of the AA patients had vit D 25-OH levels > 30 ng/mL, a level suggested for optimum regulation of PTH, calcium absorption and bone density; 30% of CA patients expressed levels above 30 ng/mL. Proteome profiling of CAL27 and SSC25 HNC cell lines following vit D treatment revealed inverse modulation of proteins linked to HNC. Proteins down-regulated by vit D treatment included nucleophosmin (NPM), lactoylglutathione, heat shock protein beta-1 (HSPB1) Peroxiredoxin-1 (PRDX1) and Ras-related protein Rap-2b. Recent reports have linked NPM with the regulation of the oncogene FOXM1, also a potential biomarker for early detection. Disease-free survival rate is improved in HNC patients with low NPM expression. Similarly, HSPB1 has been shown to be over expressed in HNC and silencing of HSPB1 has been shown to decrease metastatic behavior in HSNCC. PRDX1 displays upregulation in oral premalignancy and is an indicator for local recurrence. Histone H2A type was up-regulated by Vitamin D. Study results support that newly diagnosed AA HNC patients have depressed vit D levels compared to CA cases and that vit D treatment inversely targets select proteins dysregulated in HNC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 669. doi:1538-7445.AM2012-669

MicroRNA alterations in Barrett's esophagus, esophageal adenocarcinoma, and esophageal adenocarcinoma cell lines following cranberry extract treatment: Insights for chemoprevention

Background:

Aberrant expression of small noncoding endogenous RNA molecules known as microRNAs (miRNAs) is documented to occur in multiple cancer types including esophageal adencarcinoma (EAC) and its only known precursor, Barrett's esophagus (BE). Recent studies have linked dysregulation of specific miRNAs to histological grade, neoplastic progression and metastatic potential.

Materials and Methods:

Herein, we present a summary of previously reported dysregulated miRNAs in BE and EAC tissues as well as EAC cell lines and evaluate a cranberry proanthocyanidin rich extract's (C-PAC) ability to modulate miRNA expression patterns of three human EAC cell lines (JHEso-Ad-1, OE33 and OE19).

Results:

A review of 13 published studies revealed dysregulation of 87 miRNAs in BE and EAC tissues, whereas 52 miRNAs have been reported to be altered in BE or EAC cell lines, with 48% overlap with miRNA changes reported in tissues. We report for the first time C-PAC–induced modulation of five miRNAs in three EAC cell lines resulting in 26 validated gene targets and identification of key signaling pathways including p53, angiogenesis, T-cell activation and apoptosis. Additionally, mutiple cancer related networks were ideintified as modulated by C-PAC utilizing Kyoto Encyclopedia of Genes and Genomes (KEGG), Protein Analysis Through Evolutionary Relationships (PANTHER), and MetaCore analysis tools.

Conclusions:

Study results support the cancer inhibitory potential of C-PAC is in part attributable to C-PAC's ability to modify miRNA profiles within EAC cells. A number of C-PAC–modulated miRNAs have been been identified as dysregulated in BE and EAC. Further insights into miRNA dysregulation and modulation by select cancer preventive agents will support improved targeted interventions in high-risk cohorts.

Gankyrin, a biomarker for epithelial carcinogenesis, is overexpressed in human oral cancer

Little is known about the potential involvement of the oncoprotein gankyrin in human oral cancer progression. In this study, the levels of gankyrin mRNA and protein expression were assessed in human oral epithelial cell lines, at-risk normal oral tissues, premalignant oral lesions, and primary oral squamous cell carcinomas (OSCCs).

MATERIALS AND METHODS

Biopsies included 6 oral epithelial cell lines, 32 OSCC specimens for qRT-PCR analysis, 27 OSCC specimens and 12 premalignant oral lesions for immunohistochemical analysis.

RESULTS

Gankyrin was overexpressed in all tested oral epithelial cell lines and the majority of OSCC specimens (32/32 (100%) and 21/27 (71%) at the mRNA and protein levels, respectively). Moreover, 6/12 of premalignant oral lesions overexpressed gankyrin protein.

CONCLUSION

Gankyrin overexpression is a prevalent event in human oral cancer and occurs during the early stages of oral carcinogenesis, thus being a viable therapeutic or chemopreventive target in oral cancer.

Genetic polymorphisms of multiple DNA repair pathways impact age at diagnosis and TP53 mutations in breast cancer

Defective DNA repair may contribute to early age and late stage at time of diagnosis and mutations in critical tumor suppressor genes, such as TP53 in breast cancer. Using DNA samples from 436 breast cancer cases (374 Caucasians and 62 African-Americans), we tested these associations with 18 non-synonymous single-nucleotide polymorphisms (nsSNPs) in four DNA repair pathways: (i) base excision repair: ADPRT V762A, APE1 D148E, XRCC1 R194W/R280H/R399Q and POLD1 R119H; (ii) double-strand break repair: NBS1 E185Q and XRCC3 T241M; (iii) mismatch repair: MLH1 I219V, MSH3 R940Q/T1036A and MSH6 G39E and (iv) nucleotide excision repair: ERCC2 D312N/K751Q, ERCC4 R415Q, ERCC5 D1104H and XPC A499V/K939Q. Younger age at diagnosis (<50) was associated with ERCC2 312 DN/NN genotypes [odds ratio (OR) = 1.76; 95% confidence interval (CI) = 1.10, 2.81] and NBS1 185 QQ genotype (OR = 3.09; 95% CI = 1.47, 6.49). The XPC 939 QQ genotype was associated with TP53 mutations (OR = 5.80; 95% CI = 2.23, 15.09). There was a significant trend associating younger age at diagnosis (<50) with increasing numbers of risk genotypes for ERCC2 312 DN/NN, MSH6 39 EE and NBS1 185 QQ (P(trend) < 0.001). A similar significant trend was also observed associating TP53 mutations with increasing numbers of risk genotypes for XRCC1 399 QQ, XPC 939 QQ, ERCC4 415 QQ and XPC 499 AA (P(trend) < 0.001). Our pilot data suggest that nsSNPs of multiple DNA repair pathways are associated with younger age at diagnosis and TP53 mutations in breast cancer and larger studies are warranted to further evaluate these associations.

Abstract 846: Excess energy impacts global gene expression, proteomic profiles and histopathologic progression in a rodent model for esophageal adenocarcinoma

Rates of esophageal adenocarcinoma (EAC) have dramatically increased (500%) over the last three decades in the US resulting in EAC being identified as the fastest increasing of all cancer types. Persistent, symptomatic, reflux of gastric and duodenal contents, known as gastroesophageal disease (GERD) have long been known to correlate with Barrett's esophagus (BE) and EAC development. Recently elevated body mass index (BMI) and obesity have emerged as strong, consistent, and dose-dependent risk factors likely contributing to the rising incidence of EAC. Insights into the mechanisms underlying the obesity/GERD/EAC linkage are poorly understood; yet, urgently needed to inform preventive strategies for this extremely deadly malignancy. Two pilot studies were conducted in Sprague Dawley rodents to assess the effects of a high fat diet (40% Kcals from fat) on global gene expression changes, altered proteomic profiles and esophageal histopathologic progression given acid-reflux. Reflux was surgically induced utilizing the esophagogastroduodenal anastomosis (EGDA) rat model of EAC. Serum leptin and adiponectin levels were assessed by ELISA. Rats consuming the 40% fat diet gained significantly greater weight compared to those fed the AIN93M base diet (9% Kcals from fat). Serum leptin levels were significantly elevated in the high fat group (25.4 ng/mL vs 12.3 ng/mL). Serum adiponectin levels were significantly reduced in rats consuming the high fat diet and in rats that had undergone the EGDA surgical procedure. The esophagi of EGDA+ rats consuming the high fat diet displayed extensive histopathological changes extending 8 cm from the gastroesophageal junction. Top pathways up-regulated in the esophageal epithelium by the 40% fat diet included cytokine-cytokine receptor interaction, MAPK signaling and focal adhesion; while those down regulated included calcium signaling, focal adhesion and apoptosis. The top over-represented gene ontology category down-regulated by high fat was muscle contraction, development and regulation; whereas, the top category up-regulated by high fat was cellular process. Proteomic analysis revealed that the largest number of proteins were deregulated in the EGDA+/40% fat group followed by the EGDA-/high fat group and the EGDA+ base diet group. A partial list of proteins significantly altered in the esophagus by feeding 40% fat to the EGDA+ rats included transgelin, annexin A2, APOBEC-2, beta-enolase and troponin T3. Differential protein expression was noted for the esophageal epithelium compared to the underlying submucosa supporting that separate analysis is most informative. Cell cycle linked changes were induced in the EGDA+/high fat group. The rodent EGDA model for EAC appears promising for conducting studies focused on unraveling the molecular mechanisms involved in the obesity/GERD /EAC relationship.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 846. doi:10.1158/1538-7445.AM2011-846

Cranberry proanthocyanidins mediate growth arrest of lung cancer cells through modulation of gene expression and rapid induction of apoptosis

Cranberries are rich in bioactive constituents purported to enhance immune function, improve urinary tract health, reduce cardiovascular disease and more recently, inhibit cancer in preclinical models. However, identification of the cranberry constituents with the strongest cancer inhibitory potential and the mechanism associated with cancer inhibition by cranberries remains to be elucidated. This study investigated the ability of a proanthocyanidin rich cranberry fraction (PAC) to alter gene expression, induce apoptosis and impact the cell cycle machinery of human NCI-H460 lung cancer cells. Lung cancer is the leading cause of cancer-related deaths in the United States and five year survival rates remain poor at 16%. Thus, assessing potential inhibitors of lung cancer-linked signaling pathways is an active area of investigation.

Abstract B67: In vitro and in vivo inhibitory effects of cranberry proanthocyanidins against esophageal adenocarcinoma

This study investigated the cancer inhibitory potential of a proanthocyanidin rich cranberry extract utilizing a panel of authenticated human esophageal adenocarcinoma cell lines (EAC), a nude mouse xenograft model, and the rat esophagogastrodoudenal anastomosis (EGDA) model of EAC. PACs effects on cell morphology, global gene expression, phase of cell cycle, and cell death induction via apoptosis, autophagy, and necrosis were evaluated. Methods included RapidDiff and MDC staining, Annexin/PI and BrdU staining with flow cytometric evaluation, transmission electron microscopy (TEM), protein evaluation utilizing standard Western blot techniques, and validation of global gene expression changes by real-time PCR. PAC treatment [50-100µg/ml] of EAC cancer cell lines resulted in significant increases in apoptosis, autophagy and necrosis. Differential cell death induction was noted based upon the cell lines resistance to a bile/acid cocktail mimicking acid exposure in humans as well as the status of the apoptotic and autophagic machinery of the select cell line. PACs cell death inducing capacity correlated with altered MAPKinase signaling as evidenced by activation of P-p38 and P-JNK and inhibition of P-ERK1/2. PAC treatment induced other proapoptotic markers including cleaved PARP, BAK1, BAX, and cytochrome C, but in a cell line dependent manner. Mild increases in Beclin-1 were noted following PAC treatment, as were significant increases in LC3II, a marker of autophagasome formation which occurs during autophagy induction. Results were confirmed by TEM and MDC staining. PAC induced cell cycle arrest at the G2/M transition, increased the percent of cells in G1, caused an S-phase delay and increased P21 levels in all three cell lines. PAC administration significantly inhibited the growth of OE19 xenografts via modulation of cell cycle and MAPK signaling pathways. Oral gavage of PAC [250µg/mouse] six times a week to nude mice resulted in a 67% decrease in OE19 tumor volume, increased cytochrome C protein levels and decreased levels of P-ERK1/2, cyclin A, PCNA, and CD31 in PAC treated tumors compared to vehicle treated tumors. Lastly, a four week pilot study was performed to evaluate the safety of daily administration of PAC in the rodent EGDA model. PAC appeared well tolerated given the average daily dose of 450µg/rat/day as evidenced by normal body weight and food consumption, serology profiles and histopathology of the major organs. Further long-term studies are planned to more fully access the chemopreventive potential of PAC against esophageal adenocarcinoma and premalignancy utilizing the clinically relevant rat EGDA surgical model.

Citation Information: Cancer Prev Res 2010;3(12 Suppl):B67.

Intake of plant foods and associated nutrients in prostate cancer risk

Plant foods and associated nutrients may impact prostate cancer (PC) risk and survival. Therefore, we compared dietary intake, mainly plant food groups among 382 controls and 478 PC cases (373 incident and 105 prevalent cases). Caucasian controls had significantly higher daily servings of vegetables (3.4 vs. 2.5, P= 0.002) and fruits and/or fruit juices (1.6 vs. 1.3, P = 0.02) compared to African American controls. In Caucasians, incident cases reported lower intake of fiber, vitamin C, vitamin A, alpha -carotene, beta -carotene, cryptoxanthin, folate, genistein, daidzein, and fruits and/or fruit juice than controls and/or prevalent cases. In African Americans, incident cases had lower intake of alpha -carotene compared to controls and prevalent cases. Reduced PC risk was associated with the highest tertile of cryptoxanthin (OR = 0.51; 95% CI = 0.35-0.75), fiber (OR = 0.56; 95% CI = 0.35-0.89), vitamin C (OR = 0.60; 95% CI = 0.41-0.88), and fruits and/or fruit juices (OR = 0.46; 95% CI = 0.31-0.68), with significant linear trends. Increased risk of PC was associated with the highest tertile of protein (OR = 1.99; 95% CI = 1.05-3.79) and daily servings of grains (OR = 1.99; 95% CI = 1.23-3.22) with significant linear trends. In summary, we demonstrate racial/ethnic differences in dietary intake of plant foods. The significantly higher consumption of protective dietary constituents among prevalent cases compared to incident cases suggests that PC survivors may be amenable to dietary change.

Frequent alterations of p16INK4a and p14ARF in oral proliferative verrucous leukoplakia

Proliferative verrucous leukoplakia (PVL) represents a rare but highly aggressive form of oral leukoplakia with > 70% progressing to malignancy. Yet, PVL remains biologically and genetically poorly understood. This study evaluated the cell cycle regulatory genes, p16INK4a and p14ARF, for homozygous deletion, loss of heterozygosity, and mutation events in 20 PVL cases. Deletion of exon 1beta, 1alpha, or 2 was detected in 40%, 35%, and 0% of patients, respectively. Deletions of exons 1alpha and 1beta markedly exceed levels reported in non-PVL dysplasias and approximate or exceed levels reported in oral squamous cell carcinomas. Allelic imbalance was assessed for markers reported to be highly polymorphic in squamous cell carcinomas and in oral dysplasias. Loss of heterozygosity was detected in 35.3%, 26.3%, and 45.5% of PVLs for the markers IFNalpha, D9S1748, and D9S171, respectively. INK4a and ARF sequence alterations were detected in 20% and 10% of PVL lesions, accordingly. These data show, for the first time, that both p16INK4a and p14ARF aberrations are common in oral verrucous leukoplakia; however, the mode and incidence of inactivation events differ considerably from those reported in non-PVL oral premalignancy. Specifically, concomitant loss of p16INK4a and p14ARF occurred in 45% of PVL patients greatly exceeding loss reported in non-PVL dysplastic oral epithelium (15%). In addition, p14ARF exon 1beta deletions were highly elevated in PVLs compared with non-PVL dysplasias. These data illustrate that molecular alterations, even within a specific genetic region, are associated with distinct histologic types of oral premalignancy, which may affect disease progression, treatment strategies, and ultimately patient prognosis.

Effects of a topically applied bioadhesive berry gel on loss of heterozygosity indices in premalignant oral lesions

PURPOSE

The aim of this study was to assess the effects of topical application of a 10% (w/w) freeze-dried black raspberry (FBR) gel on oral intraepithelial neoplasia (IEN) variables that included histologic diagnoses and loss of heterozygosity (LOH) indices. Microsatellite instability and/or LOH at tumor suppressor gene-associated chromosomal loci have been associated with a higher risk for oral IEN progression to oral squamous cell carcinoma. Previously, our laboratories have shown that FBRs are well tolerated and possess potent antioxidant, apoptotic, and differentiation-inducing properties.

EXPERIMENTAL DESIGN

Each participant with IEN served as their own internal control. Before treatment, all lesions were photographed, and lesional tissue was hemisected to obtain a pretreatment diagnosis and baseline biochemical and molecular variables. Gel dosing (0.5 g applied four times daily for 6 weeks) was initiated 1 week after the initial biopsy. Genomic DNA was isolated from laser-captured basilar and suprabasilar surface epithelial cells followed by PCR amplification using primer sets that targeted known and presumed tumor suppressor gene loci associated with INK4a/ARF, p53, and FHIT. Allelic imbalance was determined by sequence analysis using normal participant tissues to establish microsatellite marker peak patterns and allele sizes.

RESULTS

Confirming earlier phase I data, none of the 27 participants developed FBR gel-associated toxicities. Furthermore, our results show histologic regression in a subset of patients as well as statistically significant reduction in LOH at tumor suppressor gene-associated loci.

CONCLUSIONS

These preliminary data suggest that further evaluation of berry gels for oral IEN chemoprevention is warranted.

Cranberry proanthocyanidins induce apoptosis and inhibit acid-induced proliferation of human esophageal adenocarcinoma cells

The occurrence of esophageal adenocarcinoma and its only recognized precursor lesion, Barrett's esophagus, has rapidly increased during the past three decades. The precise reason for the rise remains to be elucidated, but increasing rates have been linked to multiple nutritional factors. Plant-based diets have generally been associated with a reduction of risk for esophageal adenocarcinoma and those of animal origin with risk escalation. Moreover, a number of recent in vitro and limited in vivo investigations have reported that cranberry extracts affect multiple cancer-associated processes in breast, colon, prostate, and other cancer cell lines of epithelial origin. Thus, this study sought to investigate the chemopreventive potential of a cranberry proanthocyanidin rich extract (PAC) in SEG-1 human esophageal adenocarcinoma (EAC) cells. PAC pretreatment significantly inhibited the viability and proliferation of EAC cells in a time- and dose-dependent manner. Moreover, PAC (50 microg/mL) significantly inhibited acid-induced cell proliferation of SEG-1 cells. PAC treatment induced cell cycle arrest at the G1 checkpoint and significantly reduced the percentage of SEG-1 cells in S-phase following 24 and 48 h of exposure. PAC treatment also resulted in significant induction of apoptosis. Thus, PAC modulates cell cycle regulation, aberrant proliferation, and apoptosis, all key biological processes altered during progression to esophageal adenocarcinoma. These findings support that further mechanistic studies are warranted to more fully elucidate the inhibitory potential of PAC against esophageal cancer.

The effects of reactive species on the tumorigenic phenotype of human head and neck squamous cell carcinoma (HNSCC) cells

Sustained inflammation up-regulates the reactive species (RS) generating enzymes inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). While clinical data show that levels of iNOS and COX-2 are increased in epithelium during the transformation of dysplasia to overt head and neck squamous cell carcinoma (HNSCC), the mechanisms by which their overexpression contributes to HNSCC development have not been completely delineated. This study assessed the effects of RS on parameters associated with the HNSCC tumorigenic phenotype inclusive of activation of NF-kappaB (in situ immunostaining and reporter assay) and production of proinflammatory and proangiogenic proteins (ELISA analyses). Our data, which show both reactive oxygen and nitrogen species activated NF-kappaB, and that all RS donors evaluated increased HNSCC cellular production of vascular endothelial growth factor, IL-8 and epidermal growth factor receptor proteins, imply inflammation associated RS promote HNSCC by their abilities to modulate intracellular signaling and affect gene expression.

Effects of phenylethyl isothiocyanate on early molecular events in N-nitrosomethylbenzylamine-induced cytotoxicity in rat esophagus

There is little information on early molecular events in the development of N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumorigenesis and of the effects of chemopreventive agents on these events. In this study, we identified genes in rat esophagus that were differentially expressed in response to short-term NMBA treatment and modulated by cotreatment with phenylethyl isothiocyanate (PEITC). Rats were fed AIN-76A diet or AIN-76A diet containing PEITC for 3 weeks. During the 3rd week of dietary treatment, they were administered three s.c. doses of NMBA (0.5 mg/kg body weight). Rats were sacrificed 24 h after the last treatment; esophagi were excised and processed for histologic grading, microarray and real-time PCR analysis. Histopathologic analysis showed that treatment of rats with PEITC had a protective effect on NMBA-induced preneoplastic lesions in the rat esophagus. We identified 2,261 genes that were differentially expressed in the NMBA-treated versus control esophagi and 1,936 genes in the PEITC + NMBA versus NMBA-treated esophagi. The intersection of these two sets resulted in the identification of 1,323 genes in NMBA-treated esophagus, the vast majority of which were modulated by PEITC to near-normal levels of expression. Measured changes in the expression levels of eight selected genes were validated using real-time PCR. Results from 12 microarrays indicated that PEITC treatment had a genome-wide modulating effect on NMBA-induced gene expression. Samples obtained from animals treated with PEITC alone or cotreated with PEITC + NMBA were more similar to controls than to samples treated with NMBA alone.

In situ assessment of intraepithelial neoplasia in hamster trachea epithelium using angle-resolved low-coherence interferometry

Optical spectroscopy was used to evaluate the transformation of nuclear morphology associated with intraepithelial neoplasia in an animal model of carcinogenesis. In this pilot study, we have assessed the capability of angle-resolved low-coherence interferometry (a/LCI) to monitor in situ the neoplastic progression of hamster trachea epithelial tissue. By using the depth resolution made possible by coherence gating, the a/LCI system has been adapted to the unique geometry of the hamster trachea to allow us to extract useful nuclear morphometric information from cells in the epithelial layer without the need for exogenous staining or tissue fixation. Analysis of a/LCI nuclear morphology measurements has identified two important biomarkers of neoplastic transformation in hamster trachea epithelium, the size and the refractive index of epithelial cell nuclei. By comparing the a/LCI measurements of these two biomarkers to pathologic classification, we distinguished nuclear morphology changes for normal tissue, low-grade dysplasia, and high-grade dysplasia. Given its previous usefulness for tracking neoplastic change through nuclear morphometry measurements, the a/LCI technique may prove to be a useful tool in evaluating chemopreventive agents in future studies of hamster trachea epithelium.

Transitioning from preclinical to clinical chemopreventive assessments of lyophilized black raspberries: interim results show berries modulate markers of oxidative stress in Barrett's esophagus patients

Increased fruit and vegetable consumption is associated with decreased risk of a number of cancers of epithelial origin, including esophageal cancer. Dietary administration of lyophilized black raspberries (LBRs) has significantly inhibited chemically induced oral, esophageal, and colon carcinogenesis in animal models. Likewise, berry extracts added to cell cultures significantly inhibited cancer-associated processes. Positive results in preclinical studies have supported further investigation of berries and berry extracts in high-risk human cohorts, including patients with existing premalignancy or patients at risk for cancer recurrence. We are currently conducting a 6-mo chemopreventive pilot study administering 32 or 45 g (female and male, respectively) of LBRs to patients with Barrett's esophagus (BE), a premalignant esophageal condition in which the normal stratified squamous epithelium changes to a metaplastic columnar-lined epithelium. BE's importance lies in the fact that it confers a 30- to 40-fold increased risk for the development of esophageal adenocarcinoma, a rapidly increasing and extremely deadly malignancy. This is a report on interim findings from 10 patients. To date, the results support that daily consumption of LBRs promotes reductions in the urinary excretion of two markers of oxidative stress, 8-epi-prostaglandin F2alpha (8-Iso-PGF2) and, to a lesser more-variable extent, 8-hydroxy-2'-deoxyguanosine (8-OHdG), among patients with BE.

Protection against esophageal cancer in rodents with lyophilized berries: potential mechanisms

For several years, our laboratory has been evaluating the ability of lyophilized (freeze-dried) black raspberries (Rubus occidentalis, BRBs), blackberries (R. fructicosus, BBs), and strawberries (Fragaria ananasia, STRWs) to inhibit carcinogen-induced cancer in the rodent esophagus. To assure "standardized" berry preparations for study, each berry type is of the same cultivar, picked at about the same degree of ripeness, washed and frozen within 2-4 h of the time of picking, and freeze-dried under conditions that preserve the components in the berries. Some of the known chemopreventive agents in berries include vitamins A, C, and E and folic acid; calcium and selenium; beta-carotene, alpha-carotene, and lutein; polyphenols such as ellagic acid, ferulic acid, p-coumaric acid, quercetin, and several anthocyanins; and phytosterols such as beta-sitosterol, stigmasterol, and kaempferol. In initial bioassays, freeze-dried STRW, BRB, and BB powders were mixed into AIN-76A synthetic diet at concentrations of 5% and 10% and fed to Fischer 344 rats before, during, and after treatment with the esophageal carcinogen N-nitrosomethylbenzylamine (NMBA). At 25 wk of the bioassay, all three berry types were found to inhibit the number of esophageal tumors (papillomas) in NMBA-treated animals by 24-56% relative to NMBA controls. This inhibition correlated with reductions in the formation of the NMBA-induced O6-methylguanine adduct in esophageal DNA, suggesting that the berries influenced the metabolism of NMBA leading to reduced DNA damage. Studies are ongoing to determine the mechanisms by which berries influence NMBA metabolism and DNA adduct formation. BRBs and STRWs were also tested in a postinitiation scheme and were found to inhibit NMBA-induced esophageal tumorigenesis by 31-64% when administered in the diet following treatment of the animals with NMBA. Berries, therefore, inhibit tumor promotion and progression events as well as tumor initiation. In vivo mechanistic studies with BRBs indicate that they reduce the growth rate of premalignant esophageal cells, in part, through down-regulation of cyclooxygenase-2 leading to reduced prostaglandin production and of inducible nitric oxide synthase leading to reduced nitrate/nitrite levels in the esophagus. Based upon the preclinical data on rodents, we have initiated prevention trials in humans to determine if berries might exhibit chemopreventive effects in the esophagus.

Protection against esophageal cancer in rodents with lyophilized berries: potential mechanisms

For several years, our laboratory has been evaluating the ability of lyophilized (freeze-dried) black raspberries (Rubus occidentalis, BRBs), blackberries (R. fructicosus, BBs), and strawberries (Fragaria ananasia, STRWs) to inhibit carcinogen-induced cancer in the rodent esophagus. To assure "standardized" berry preparations for study, each berry type is of the same cultivar, picked at about the same degree of ripeness, washed and frozen within 2-4 h of the time of picking, and freeze-dried under conditions that preserve the components in the berries. Some of the known chemopreventive agents in berries include vitamins A, C, and E and folic acid; calcium and selenium; beta-carotene, alpha-carotene, and lutein; polyphenols such as ellagic acid, ferulic acid, p-coumaric acid, quercetin, and several anthocyanins; and phytosterols such as beta-sitosterol, stigmasterol, and kaempferol. In initial bioassays, freeze-dried STRW, BRB, and BB powders were mixed into AIN-76A synthetic diet at concentrations of 5% and 10% and fed to Fischer 344 rats before, during, and after treatment with the esophageal carcinogen N-nitrosomethylbenzylamine (NMBA). At 25 wk of the bioassay, all three berry types were found to inhibit the number of esophageal tumors (papillomas) in NMBA-treated animals by 24-56% relative to NMBA controls. This inhibition correlated with reductions in the formation of the NMBA-induced O6-methylguanine adduct in esophageal DNA, suggesting that the berries influenced the metabolism of NMBA leading to reduced DNA damage. Studies are ongoing to determine the mechanisms by which berries influence NMBA metabolism and DNA adduct formation. BRBs and STRWs were also tested in a postinitiation scheme and were found to inhibit NMBA-induced esophageal tumorigenesis by 31-64% when administered in the diet following treatment of the animals with NMBA. Berries, therefore, inhibit tumor promotion and progression events as well as tumor initiation. In vivo mechanistic studies with BRBs indicate that they reduce the growth rate of premalignant esophageal cells, in part, through down-regulation of cyclooxygenase-2 leading to reduced prostaglandin production and of inducible nitric oxide synthase leading to reduced nitrate/nitrite levels in the esophagus. Based upon the preclinical data on rodents, we have initiated prevention trials in humans to determine if berries might exhibit chemopreventive effects in the esophagus.

Chemopreventive effects of a selective nitric oxide synthase inhibitor on carcinogen-induced rat esophageal tumorigenesis

The inducible nitric oxide synthase (iNOS) generates a high concentration of nitric oxide (NO) in tissues. Increased NO production is associated with many disorders including esophageal cancer. Previous studies in our laboratory demonstrated an association between increased iNOS expression and the development of N-nitrosomethylbenzylamine (NMBA)-induced tumors in the rat esophagus. On the basis of these observations, we initiated a bioassay to evaluate the ability of S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea (PBIT), a selective iNOS inhibitor, to prevent the progression of esophageal tumors in rats preinitiated with NMBA. Rats were given s.c. injections of NMBA (0.25 mg/kg body weight) three times per week for 5 weeks. One week later, they were fed a synthetic diet containing either 50 or 100 ppm PBIT until the end of the bioassay (25 weeks). PBIT reduced the incidence of esophageal cancer from 96% in NMBA-treated rats to 83% and 77% (P < 0.05) in rats treated with 50 and 100 ppm PBIT, respectively. Tumor multiplicity was reduced from 3.64 +/- 0.42 tumors per esophagus in NMBA-treated rats to 1.79 +/- 0.25 (P < 0.001) and 1.50 +/- 0.24 (P < 0.0001) in rats treated with 50 and 100 ppm PBIT, respectively. PBIT reduced the production of NO in NMBA-induced preneoplastic and papillomatous esophageal lesions when compared with comparable lesions in rats treated with NMBA only. iNOS mRNA expression was not modulated by PBIT. These observations suggest that iNOS plays a role in tumor development and that its selective inhibitor, PBIT, significantly inhibits esophageal tumor progression presumably through reducing the production of NO.

Chemoprevention of oral cancer by black raspberries

Oral cavity cancers represent 2.5% of the cancers that occur in the United States and are ranked sixth worldwide. Since current therapeutic protocols are relatively ineffective, alternative strategies for prevention need to be developed and tested in appropriate animal models. In the study reported herein, the hamster cheek pouch (HCP) was used to evaluate the ability of black raspberries to inhibit oral cavity tumors. Male Syrian Golden hamsters, 3-4 weeks of age, were fed 5% and 10% lyophilized black raspberries (LBR) in the diet for two weeks prior to treatment with 0.2% 7,12-dimethylbenz(a) anthracene in dimethylsulfoxide and for 10 weeks thereafter. HCPs were painted 3X/week for eight weeks. The animals were sacrificed 12-13 weeks from the beginning of DMBA treatment and the number and volume of tumors (mm3) determined. There was a significant difference (p = 0.02) in the number of tumors between the 5% LBR and control groups (27 tumors/14 animals and 48 tumors/15 animals, respectively) and an intermediate number of tumors in the 10% berry-treated animals (39 tumors/15 animals). These experiments support previous studies from our laboratories showing the chemopreventive activity of black raspberries and show, for the first time, that dietary black raspberries will inhibit tumor formation in the oral cavity.

Effects of lyophilized black raspberries on azoxymethane-induced colon cancer and 8-hydroxy-2'-deoxyguanosine levels in the Fischer 344 rat

This study examined the effects of lyophilized black raspberries (BRB) on azoxymethane (AOM)-induced aberrant crypt foci (ACF), colon tumors, and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in male Fischer 344 rats. AOM was injected (15 mg/kg body wt i.p.) once per week for 2 wk. At 24 h after the final injection, AOM-treated rats began consuming diets containing 0%, 2.5%, 5%, or 10% (wt/wt) BRB. Vehicle controls received 5% BRB or diet only. Rats were sacrificed after 9 and 33 wk of BRB feeding for ACF enumeration and tumor analysis. ACF multiplicity decreased 36%, 24%, and 21% (P < 0.01 for all groups) in the 2.5%, 5%, and 10% BRB groups, respectively, relative to the AOM-only group. Total tumor multiplicity declined 42%, 45%, and 71% (P < 0.05 for all groups). Although not significant, a decrease in tumor burden (28%, 42%, and 75%) was observed in all BRB groups. Adenocarcinoma multiplicity decreased 28%, 35%, and 80% (P < 0.01) in the same treatment groups. Urinary 8-OHdG levels were reduced by 73%, 81%, and 83% (P < 0.01 for all groups). These results indicate that BRB inhibit several measures of AOM-induced colon carcinogenesis and modulate an important marker of oxidative stress in the Fischer 344 rat.

Alterations of p16(INK4a) and p14(ARF) in patients with severe oral epithelial dysplasia

A number of genetic aberrations have been reported in end-stage squamous cell carcinoma of the head and neck, including p16(INK4a) and p14(ARF) (INK4a/ARF) inactivation rates of 70-85%. Still, the cell cycle-regulatory genes p16(INK4a) and p14(ARF) remain poorly understood in oral cavity premalignant lesions. This study evaluated INK4a/ARF locus alterations in 26 patients (28 samples) deemed to be at increased risk for malignant transformation to squamous cell carcinoma due to the diagnosis of severe oral epithelial dysplasia. Microscopically confirmed dysplastic oral epithelium and matching normal tissue were laser capture-microdissected from paraffin sections, DNA was isolated, and molecular techniques were used to evaluate p16(INK4a) and p14(ARF) gene deletion, mutation, loss of heterozygosity (LOH), and hypermethylation events. Deletion of exon 1beta, 1alpha, or 2 was detected in 3.8%, 11.5%, and 7.7% of patients, respectively. INK4a and ARF mutations were detected in 15.4% and 11.5% of patients with severe dysplasia of the oral epithelium. All identified mutations occurred in the INK4a/ARF conserved exon 2. Allelic imbalance was assessed using three markers previously reported to show high LOH rates in head and neck tumors. LOH was found in 42.1%, 35.0%, and 82.4% of patients for the markers IFNalpha, D9S1748, and D9S171, respectively. Hypermethylation of p16(INK4a) and p14(ARF) was detected in 57.7% and 3.8% of patients, respectively, using nested, two-stage methylation-specific PCR. The highest rates of p16(INK4a) hypermethylation occurred in lesions of the tongue and floor of the mouth. In addition, p16(INK4a) hypermethylation was significantly linked to LOH in two or more markers. These data support that INK4a/ARF locus alterations are frequent events preceding the development of oral cancer and that p16(INK4a) inactivation occurs to a greater extent in oral dysplasia than does p14(ARF) inactivation.

Incidence and effects of Ha-ras codon 12 G-->A transition mutations in preneoplastic lesions induced by N-nitrosomethylbenzylamine in the rat esophagus

N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumorigenesis is an important model for squamous cell carcinoma of the human esophagus. In this model, previous studies have shown that the GGA-->GAA Ha-ras codon 12 mutation is present in the majority of papillomas. No other Ha-ras mutation has been identified. Studies using other models of chemical carcinogenesis suggest that Ha-ras activation has a critical role during tumor initiation. We have used laser-capture microdissection and polymerase chain reaction-restriction fragment length polymorphism analysis to study the role of codon 12 Ha-ras mutation at various stages of tumor development in the rat esophagus. Our results indicate that Ha-ras mutation was present infrequently (4.3%) in premalignant lesions. The incidence of Ha-ras mutation was high in papillomas (57.1%), however, and 50% of papillomas expressed mutant Ha-ras RNA message. Additionally, there was a linear trend correlating increased incidence of Ha-ras mutation with later papilloma stage. These data suggest the role of ras activation later in neoplastic development. To evaluate the potential mechanism of action by which Ha-ras contributes to promotion and progression in this model, we compared mRNA expression of cyclin D1 and p27 in Ha-ras mutant and Ha-ras normal papillomas. We found no differences in mRNA expression of either cyclin D1 or p27 between these two papilloma populations. Our data suggest an important paradigm shift for the role of ras mutations in this model of chemical carcinogenesis, indicating a functional role of Ha-ras activation in promotion/progression and not in the initiation phase of NMBA-induced papillomagenesis.

Chemoprevention of esophageal tumorigenesis by dietary administration of lyophilized black raspberries

Fruit and vegetable consumption has consistently been associated with decreased risk of a number of aerodigestive tract cancers, including esophageal cancer. We have taken a "food-based" chemopreventive approach to evaluate the inhibitory potential of lyophilized black raspberries (LBRs) against N-nitrosomethylbenzylamine (NMBA)-induced esophageal tumorigenesis in the F344 rat, during initiation and postinitiation phases of carcinogenesis. Anti-initiation studies included a 30-week tumorigenicity bioassay, quantification of DNA adducts, and NMBA metabolism study. Feeding 5 and 10% LBRs, for 2 weeks prior to NMBA treatment (0.25 mg/kg, weekly for 15 weeks) and throughout a 30-week bioassay, significantly reduced tumor multiplicity (39 and 49%, respectively). In a short-term bioassay, 5 and 10% LBRs inhibited formation of the promutagenic adduct O(6)-methylguanine (O(6)-meGua) by 73 and 80%, respectively, after a single dose of NMBA at 0.25 mg/kg. Feeding 5% LBRs also significantly inhibited adduct formation (64%) after NMBA administration at 0.50 mg/kg. The postinitiation inhibitory potential of berries was evaluated in a second bioassay with sacrifices at 15, 25, and 35 weeks. Administration of LBRs began after NMBA treatment (0.25 mg/kg, three times per week for 5 weeks). LBRs inhibited tumor progression as evidenced by significant reductions in the formation of preneoplastic esophageal lesions, decreased tumor incidence and multiplicity, and reduced cellular proliferation. At 25 weeks, both 5 and 10% LBRs significantly reduced tumor incidence (54 and 46%, respectively), tumor multiplicity (62 and 43%, respectively), proliferation rates, and preneoplastic lesion development. Yet, at 35 weeks, only 5% LBRs significantly reduced tumor incidence and multiplicity, proliferation indices and preneoplastic lesion formation. In conclusion, dietary administration of LBRs inhibited events associated with both the initiation and promotion/progression stages of carcinogenesis, which is promising considering the limited number of chemopreventives with this potential.