AXL Promotes Metformin-Induced Apoptosis Through Mediation of Autophagy by Activating ROS-AMPK-ULK1 Signaling in Human Esophageal Adenocarcinoma

AXL receptor tyrosine kinase promotes an invasive phenotype and chemotherapy resistance in esophageal adenocarcinoma (EAC). AXL has been implicated in the regulation of autophagy, but the underlying molecular mechanism remains poorly understood. Herein, we investigate the mechanistic role of AXL in autophagy as well as metformin-induced effects on the growth and survival of EAC. We demonstrate that AXL mediates autophagic flux through activation of AMPK-ULK1 signaling in a reactive oxygen species (ROS)-dependent mechanism by glucose starvation. AXL positively regulates basal cellular ROS levels without significantly affecting mitochondrial ROS production in EAC cells. Pharmacological inhibition of cellular ROS using Trolox abrogates glucose starvation-induced AMPK signaling and autophagy. We demonstrate that AXL expression is required for metformin-induced apoptosis in EAC cells in vitro. The apoptosis induction by metformin is markedly attenuated by inhibition of autophagy through genetic silencing of Beclin1 or ATG7 autophagy mediators, thereby confirming the requirement of intact autophagy for enhancing metformin-induced apoptosis in EAC cells. Our data indicate that metformin-induced autophagy displays a pro-apoptotic function in EAC cells. We show that the metformin-induced suppression of tumor growth in vivo is highly dependent on AXL expression in a tumor xenograft mouse model of EAC. We demonstrate that AXL promotes metformin-induced apoptosis through activation of autophagy in EAC. AXL may be a valuable biomarker to identify tumors that are sensitive to metformin. Therefore, AXL expression could inform the selection of patients for future clinical trials to evaluate the therapeutic efficacy of metformin in EAC

Molecular testing for the clinical diagnosis of fibrolamellar carcinoma.

Fibrolamellar carcinoma has a distinctive morphology and immunophenotype, including cytokeratin 7 and CD68 co-expression. Despite the distinct findings, accurate diagnosis of fibrolamellar carcinoma continues to be a challenge. Recently, fibrolamellar carcinomas were found to harbor a characteristic somatic gene fusion, DNAJB1-PRKACA. A break-apart fluorescence in situ hybridization (FISH) assay was designed to detect this fusion event and to examine its diagnostic performance in a large, multicenter, multinational study. Cases initially classified as fibrolamellar carcinoma based on histological features were reviewed from 124 patients. Upon central review, 104 of the 124 cases were classified histologically as typical of fibrolamellar carcinoma, 12 cases as 'possible fibrolamellar carcinoma' and 8 cases as 'unlikely to be fibrolamellar carcinoma'. PRKACA FISH was positive for rearrangement in 102 of 103 (99%) typical fibrolamellar carcinomas, 9 of 12 'possible fibrolamellar carcinomas' and 0 of 8 cases 'unlikely to be fibrolamellar carcinomas'. Within the morphologically typical group of fibrolamellar carcinomas, two tumors with unusual FISH patterns were also identified. Both cases had the fusion gene DNAJB1-PRKACA, but one also had amplification of the fusion gene and one had heterozygous deletion of the normal PRKACA locus. In addition, 88 conventional hepatocellular carcinomas were evaluated with PRKACA FISH and all were negative. These findings demonstrate that FISH for the PRKACA rearrangement is a clinically useful tool to confirm the diagnosis of fibrolamellar carcinoma, with high sensitivity and specificity. A diagnosis of fibrolamellar carcinoma is more accurate when based on morphology plus confirmatory testing than when based on morphology alone

Epithelioid sarcoma presenting as radial mononeuropathy: anatomical, magnetic resonance neurography and diffusion tensor imaging appearances

The authors report an unusual case of radial mononeuropathy caused by epithelioid sarcoma and describe the anatomical 3-Tesla MR neurography and the functional diffusion tensor imaging findings of the case, which were subsequently confirmed on surgical excision and histopathology

Composite intestinal adenoma-microcarcinoid clues to diagnosing an under-recognised mimic of invasive adenocarcinoma

Aims Microcarcinoids refer to microscopic nests of monotonous cells with endocrine and squamoid features. Their peculiar morphology can appear infiltrative with a desmoplastic-like background, raising concerns for an infiltrating adenocarcinoma. To further characterise microcarcinoids, we undertook a prospective clinicopathological study. Methods 11 specimens originating from five men and six women (average age=58.9 years) were prospectively collected from December 2004 to December 2011. Results Microcarcinoids were most commonly identified in high-risk adenomas (size ≥10 mm (n=10), villous components (n=8) and/or high-grade dysplasia (n=4)). All polyps had mucosal prolapse and four displayed background fibrosis reminiscent of desmoplasia. The microcarcinoid component was most often multifocal (n=7) within the individual polyp and extended over an average length of 3.9 mm. The individual microcarcinoid cells were cuboidal with abundant eosinophilic cytoplasm. All cases had monotonous nuclei which lacked pleomorphism, hyperchromasia and mitotic activity. All available microcarcinoids were β-catenin and synaptophysin reactive and non-reactive for chromogranin and p53 with a negligible Ki-67 proliferation index (<2%). In addition, the microcarcinoids were variably reactive for p63 and/or CK 5/6, thereby demonstrating focal squamoid features. Two of the study cases were submitted with a concern for invasive carcinoma. Clinical information was available in 10 patients with up to 24 months of follow-up: all patients are alive and well and no subsequent malignancy has been reported. Conclusions Awareness of this unique morphology is important to avoid overdiagnosing microcarcinoids as invasive adenocarcinoma. Moreover, this immunohistochemical panel can be helpful in discriminating microcarcinoids from its malignant mimic in challenging cases

Upper GI Tract Lesions in Familial Adenomatous Polyposis (FAP)

Patients with familial adenomatous polyposis (FAP), an autosomal dominant cancer predisposition syndrome caused by mutations in the APC gene, develop neoplasms in both the upper and lower gastrointestinal (GI) tract. To clarify the upper GI tract lesions in FAP patients in a tertiary care setting, we reviewed specimens from 321 endoscopies in 66 patients with FAP. Tubular adenomas in the small bowel were the most common neoplasms (present in 89% of patients), although only 1 patient developed invasive carcinoma of the small bowel. Several types of gastric neoplasms were identified—65% of patients had at least 1 fundic gland polyp, and 23% of patients had at least 1 gastric foveolar–type gastric adenoma. Pyloric gland adenomas were also enriched, occurring in 6% of patients—this is a novel finding in FAP patients. Despite the high frequency of gastric neoplasms, only 1 patient developed carcinoma in the stomach. The very low frequency of carcinoma in these patients suggests that current screening procedures prevent the vast majority of upper GI tract carcinomas in patients with FAP, at least in the tertiary care setting

Upper GI tract lesions in familial adenomatous polyposis (FAP): enrichment of pyloric gland adenomas and other gastric and duodenal neoplasms

Patients with familial adenomatous polyposis (FAP), an autosomal dominant cancer predisposition syndrome caused by mutations in the APC gene, develop neoplasms in both the upper and lower gastrointestinal (GI) tract. To clarify the upper GI tract lesions in FAP patients in a tertiary care setting, we reviewed specimens from 321 endoscopies in 66 patients with FAP. Tubular adenomas in the small bowel were the most common neoplasms (present in 89% of patients), although only 1 patient developed invasive carcinoma of the small bowel. Several types of gastric neoplasms were identified--65% of patients had at least 1 fundic gland polyp, and 23% of patients had at least 1 gastric foveolar-type gastric adenoma. Pyloric gland adenomas were also enriched, occurring in 6% of patients--this is a novel finding in FAP patients. Despite the high frequency of gastric neoplasms, only 1 patient developed carcinoma in the stomach. The very low frequency of carcinoma in these patients suggests that current screening procedures prevent the vast majority of upper GI tract carcinomas in patients with FAP, at least in the tertiary care setting

Co-overexpression of AXL and c-ABL predicts a poor prognosis in esophageal adenocarcinoma and promotes cancer cell survival

Esophageal adenocarcinoma (EAC) is highly aggressive and characterized by poor prognosis. AXL expression has been linked to Barrett's tumorigenesis and resistance to chemotherapy, which is associated with c-ABL intracellular localization. However, the molecular and functional relationship between AXL and c-ABL and the clinical significance of the co-expression of these proteins in EAC remain unclear. We used immunohistochemical analysis (IHC) on tissue microarrays containing human EAC samples (n=53) and normal esophageal tissues (n=11) in combination with corresponding deidentified clinicopathological information to evaluate the expression and the prognostic significance of AXL and c-ABL in EAC. The data were statistically analyzed using Kruskal-Wallis, the chi-square, the Fisher's exact, and Pearson tests. The Kaplan-Meier method and Cox proportional hazards regression model were used to evaluate cancer patient survival. We used a serum deprivation EAC cell model to investigate the pro-survival function of AXL and c-ABL using cell viability, apoptosis, and lactate dehydrogenase activity assays. We performed assays, including Western blotting, quantitative real-time PCR, and translational chromatin immunoprecipitation (TrIP-Chip) to study the molecular relationship between AXL and c-ABL in EAC cells. IHC analysis revealed that AXL and c-ABL were overexpressed in 55% and 66% of EAC samples, respectively, as compared to normal tissues. Co-overexpression of the two proteins was observed in 49% of EAC samples. The chi-square test indicated a significant association between AXL and c-ABL expression in the EAC samples (χ = 6.873, 0.032), and the expression of these proteins was significantly associated with EAC patient age ( 0.001), tumor stage ( 0.01), and lymph node status ( 0.001). AXL and c-ABL protein expression data analysis exhibited an identical clinicopathological association profile. Additionally, we found a significant association between expression of AXL (χ = 16.7, 0.002) or c-ABL (χ = 13.4, 0.001) and survival of EAC patients. The Cox proportional hazards model and log rank test predicted a significant increase in mortality of patients with high expression of AXL [hazard ratio (HR): 2.86, 95% confidence interval (CI): 1.53 - 5.34, 0.003] or c-ABL [HR: 3.29, 95% CI: 1.35 - 8.03, 0.001] as compared to those patients with low expression of AXL or c-ABL proteins. Molecular investigations indicated that AXL positively regulates c-ABL protein expression through increased cap-dependent protein translation involving phosphorylation of EIF4E in EAC cells. Next, we investigated the functional relationship between AXL and c-ABL in EAC cells. We demonstrated that the pro-survival activity of AXL requires c-ABL expression in response to serum deprivation. This study highlights the importance of the co-overexpression of AXL and c-ABL proteins as a valuable prognostic biomarker and targeting these proteins could be an effective therapeutic approach in EAC or other solid tumors expressing high levels of AXL and c-ABL proteins

A Comparative Clinicopathologic Study of Collagenous Gastritis in Children and Adults The Same Disorder With Associated Immune-mediated Diseases

Collagenous gastritis is a rare condition characterized by surface epithelial damage, subepithelial collagen deposition, and a lamina propria inflammatory infiltrate. Previous studies have proposed 2 clinicopathologic subtypes: (1) children (18 y of age or younger) presenting with severe anemia, nodular gastric mucosa, and isolated gastric disease; and (2) adults with chronic watery diarrhea that is associated with diffuse collagenous involvement of the gastrointestinal tract. However, notable exceptions exist. In fact, broad variability in clinical presentation, etiology, treatment and disease course has been reported. To better define the clinicopathologic features of collagenous gastritis, we have collected 10 pediatric and 21 adult cases and describe their clinical, endoscopic, pathologic, and follow-up findings. Both children and adults presented with similar clinical symptoms such as anemia (50%, 35%, respectively), epigastric/abdominal pain (50%, 45%), and diarrhea (40%, 55%). Concomitant immune disorders were identified in 2 (20%) children and 3 (14%) adults. Further, 7 of 17 (41%) adults were taking medications associated with other immune-related gastrointestinal diseases including olmesartan and antidepressants. Histologically, there were no differences between children and adults with collagenous gastritis in the location of gastric involvement, mean collagenous layer thickness, and prominence of eosinophils (P > 0.05). Extragastric collagenous involvement was also seen with comparable frequencies in each cohort (44%, 59%). Follow-up information was available for 22 of 31 (71%) patients and ranged from 2 to 122 months (mean, 33.6mo). Despite medical management in most cases, persistence of symptoms or collagenous gastritis on subsequent biopsies was seen in 100% of children and 82% of adults. Of note, treatment for 1 adult patient involved cessation of olmesartan resulting in resolution of both symptoms and subepithelial collagen deposition on subsequent biopsies. Contrary to prior reports, no clinicopathologic differences were identified among pediatric and adult patients with collagenous gastritis. Whereas collagenous gastritis remains an enigmatic condition, our findings suggest that immune abnormalities and medications, such as olmesartan, may be possible triggers. However, current treatment options have had limited success and, thus, highlight the need for improved therapeutic regimens

Phase I study combining the aurora kinase a inhibitor alisertib with mFOLFOX in gastrointestinal cancer

Overexpression and cellular mis-localization of aurora kinase A (AURKA) in gastrointestinal cancers results in chromosomal instability, activation of multiple oncogenic pathways, and inhibition of pro-apoptotic signaling. Inhibition of AURKA causes mitotic delays, severe chromosome congression, and activation of p53/p73 leading to cell death. Our preclinical data showed cooperative activity with the AURKA inhibitor alisertib and platinum agents in cell lines and xenografts, and suggested an optimal treatment window. Therefore, this study was designed to determine the maximum-tolerated dose (MTD) of alisertib in combination with modified FOLFOX (mFOLFOX), as this is a standard platinum-based therapy for gastrointestinal cancers. Standard 3 + 3 dose escalation was used, where the starting dose of alisertib was 10 mg twice daily (Days 1-3), with leucovorin (400 mg/m ) and oxaliplatin (85 mg/m ) on Day 2 followed by continuous 46-h 5-FU (2400 mg/m ) infusion on Days 2-4 in 14-day cycles. Fourteen patients with advanced gastrointestinal cancers were enrolled and two doses explored; two patients were not evaluable for dose-limiting toxicity (DLT) and replaced. Two patients experienced DLTs at 20 mg of alisertib (Grade 3 fatigue (n = 2); Grade 3 nausea, vomiting, dehydration with hospitalization (n = 1)). MTD was 10 mg alisertib with 85 mg/m oxaliplatin and 2400 mg/m 5-FU. Most frequent toxicities were nausea (57%), diarrhea, fatigue, neuropathy, and vomiting (43%), and anorexia and anemia (36%); most were Grade 1-2. One patient with colorectal cancer had a partial response of 12 evaluable patients, and four patients had stable disease. Alisertib in combination with mFOLFOX did not demonstrate unexpected side effects, but the regimen was only tolerable at the lowest dose investigated