Preclinical Study of AUY922, a Novel Hsp90 Inhibitor, in the Treatment of Esophageal Adenocarcinoma.

OBJECTIVE: To assess the efficacy of heat-shock protein 90 (Hsp90) inhibitor, NVP-AUY922-AG (AUY922), in the treatment of esophageal adenocarcinoma (EAC) in vitro and in vivo. BACKGROUND: EAC is a leading cause of cancer death, and current treatment options are limited. Hsp90, a chaperone protein that regulates several oncoproteins, is upregulated in EAC, and may be a novel target for therapy. METHODS: In vitro, EAC cell lines were utilized to evaluate AUY922, alone and in combination with 5-fluorouracil (5-FU) and cisplatin. BrdU ELISA and flow cytometry were used to assess proliferation and measure apoptosis, respectively. Western blot and RT-PCR were performed to quantitate Hsp90 pathway expression. In vivo, esophagojejunostomy was performed on rats and treatment animals received AUY922 32 to 40 weeks postoperatively. Drug efficacy was evaluated with magnetic resonance imaging (MRI), endoscopic biopsy, gross histological evaluation, and Hsp90 pathway expression. RESULTS: In vitro, AUY922 demonstrated antiproliferative activity in both cell lines and showed enhanced efficacy with cisplatin and 5-FU. Western Blot and RT-PCR demonstrated downregulation of CDK1 and CDK4 and upregulation of Hsp72. In vivo, AUY922 showed decrease in tumor volume in 36.4% of rats (control = 9.4%), increase in 9.1% (control = 37.5%), and stable disease in 54.5% (control = 43.7%). Necropsy confirmed the presence of EAC in 50% of treatment animals and 75% of control animals. mRNA expression, pre- and posttreatment, demonstrated significant downregulation of MIF, Hsp70, Hsp90ß, and CDK4, and upregulation of Hsp72. CONCLUSIONS: AUY922 exhibits antitumor efficacy in vitro and in vivo for EAC, suggesting the need for human clinical trials.

Hypopharyngeal pepsin and Sep70 as diagnostic markers of laryngopharyngeal reflux: preliminary study.

INTRODUCTION: The management of laryngopharyngeal reflux (LPR) has been challenging. Hypopharyngeal multichannel intraluminal impedance (HMII) has shown to increase the sensitivity in diagnosing LPR. The objective of this study is to investigate the potential use of pepsin and Sep70 as diagnostic tools for detection of LPR in combination with HMII. MATERIALS AND METHODS: Tissue samples of hypopharynx, distal esophagus, and gastric cardia were collected from patients with LPR symptoms regardless of gastroesophageal reflux (GERD) diagnosis and underwent HMII to detect LPR and high esophageal reflux (HER: reflux 2 cm distal to upper esophageal sphincter) events. Patients were classified into two groups based on the presence of abnormal proximal exposure (APE), which was defined as LPR ≥1/day and/or HER ≥5/day: (1) positive-APE and (2) negative-APE. Patients with typical GERD symptoms without LPR symptoms who did not undergo HMII were used as a "control" GERD group. Protein was isolated from tissue samples and Western blot analysis of pepsin and Sep70 was performed. Pepsinogen was used as a control to differentiate pepsin from pepsinogen. Relative quantitation was performed using Image Studio Lite Software with normalization against the internal actin of each blot. RESULTS: From October 2012 to September 2013, 55 patients underwent HMII. Of 55, 20 patients underwent biopsies from hypopharynx (17 positive-APE and 3 negative-APE). Ten patients with typical GERD symptoms were identified from tissue bank as a "control" GERD group. Pepsin was detected in distal esophagus and hypopharynx in all groups without significant difference among groups. However, Sep70 in distal esophagus and hypopharynx was significantly depleted in the positive-APE group compared to the other groups (p = 0.032 and 0.002, respectively). CONCLUSION: Depletion of Sep70 with the presence of pepsin in the hypopharynx may indicate cellular injury in laryngopharynx due to constant proximal reflux. However, the normative data for these markers have to be validated.

Prognostic value and targeted inhibition of survivin expression in esophageal adenocarcinoma and cancer-adjacent squamous epithelium.

BACKGROUND: Survivin is an inhibitor of apoptosis and its over expression is associated with poor prognosis in several malignancies. While several studies have analyzed survivin expression in esophageal squamous cell carcinoma, few have focused on esophageal adenocarcinoma (EAC) and/or cancer-adjacent squamous epithelium (CASE). The purpose of this study was 1) to determine the degree of survivin up regulation in samples of EAC and CASE, 2) to evaluate if survivin expression in EAC and CASE correlates with recurrence and/or death, and 3) to examine the effect of survivin inhibition on apoptosis in EAC cells. METHODS: Fresh frozen samples of EAC and CASE from the same patient were used for qRT-PCR and Western blot analysis, and formalin-fixed, paraffin-embedded tissue was used for immunohistochemistry. EAC cell lines, OE19 and OE33, were transfected with small interfering RNAs (siRNAs) to knockdown survivin expression. This was confirmed by qRT-PCR for survivin expression and Western blot analysis of cleaved PARP, cleaved caspase 3 and survivin. Survivin expression data was correlated with clinical outcome. RESULTS: Survivin expression was significantly higher in EAC tumor samples compared to the CASE from the same patient. Patients with high expression of survivin in EAC tumor had an increased risk of death. Survivin expression was also noted in CASE and correlated with increased risk of distant recurrence. Cell line evaluation demonstrated that inhibition of survivin resulted in an increase in apoptosis. CONCLUSION: Higher expression of survivin in tumor tissue was associated with increased risk of death; while survivin expression in CASE was a superior predictor of recurrence. Inhibition of survivin in EAC cell lines further showed increased apoptosis, supporting the potential benefits of therapeutic strategies targeted to this marker.

Smoothened inhibition leads to decreased proliferation and induces apoptosis in esophageal adenocarcinoma cells.

The Hedgehog (Hh) pathway is known to be active in Barrett's carcinogenesis. Therefore, we evaluated the efficacy and underlying mechanisms of inhibition of cancer cell growth by the smoothened (Smo) antagonist BMS-833923 in esophageal adenocarcinoma (EAC) cell lines. Cell proliferation and apoptosis were evaluated by flow cytometry, Western blotting, immunofluorescence, and quantitative reverse transcription polymerase chain reactions. Results showed that the Smo antagonist led to reduced Hh pathway activity, resulting in decreased cell proliferation and induction of apoptosis via the intrinsic pathway in the esophageal cancer cells. In conclusion, the Smo antagonist may have application as an EAC chemotherapeutic agent.

Prevention of Barrett esophagus and esophageal adenocarcinoma by smoothened inhibitor in a rat model of gastroesophageal reflux disease.

BACKGROUND: Activated hedgehog (Hh) pathway is associated with development of both Barrett esophagus (BE) and esophageal adenocarcinoma (EAC). We hypothesize that blockade of the Hh pathway with smoothened (Smo) inhibitor can prevent the development of BE/EAC in the Levrat model, in which induced gastroduodenoesophageal reflux (GDER) leads to esophageal carcinogenesis. METHODS: GDER was induced in 6- to 8-week-old male Sprague-Dawley rats. The Smo inhibitor (10 mg/kg/d) was given orally on postoperative weeks 10 to 16, 18 to 22, and 24 to 28, and rats were killed on week 28. The primary outcome measure was the incidence of BE and EAC. To examine potential therapeutic effects of Smo inhibition on tumor tissue, semiquantitative immunohistochemistry for Ki-67 and caspase 3 was performed. In treated animals that developed cancer, gene expression was analyzed. RESULTS: Thirty-eight of 48 controls and 32 of 46 treated animals survived to 28 weeks. messenger ribonucleic acid (mRNA) expression of Indian Hh, a ligand of transmembrane receptor patched 1, was 184× higher in BE and 99× higher in EAC compared with normal esophageal tissue (P = 0.0239 and P = 0.0004, respectively). Compared with controls, the incidence of BE and EAC was decreased in treated animals by 35.7% (relative risk reduction, 36%; P = 0.0015) and 36% (relative risk reduction, 62%; P = 0.0033), respectively. Compared with untreated EAC, Ki-67 was downregulated (P = 0.04) and cleaved caspase 3 was no different in treated EAC (P = 0.398). Of the 84 well-known genes involved in cancer drug resistance, 50 were dysregulated in treated EAC (P < 0.05 for each gene). CONCLUSIONS: Smo inhibitor prevents the development of BE and EAC in an in vivo model of GDER.