Oestrogen Receptor Isoforms May Represent a Therapeutic Target in Oesophageal Adenocarcinoma.

Oesophageal adenocarcinoma is a rapidly increasing problem in which treatment options are limited. Previous studies have shown that oesophageal adenocarcinoma cells and tissues express oestrogen receptors (ERs) and show growth suppression and apoptosis in response to ER modulator agents such as tamoxifen. ERs are known to be expressed in a number of isoforms that act together to regulate cell growth and cell death. In this study, we used western blotting to profile the expression of ERα and ERß isoforms, and expression of the oncologically related molecules p53, HER2, and EGFR, in a panel of oesophageal adenocarcinoma cell lines. The cytotoxicity of tamoxifen in the cell lines was determined with Annexin V-FITC flow cytometry, and correlations between cytotoxicity and receptor expression were assessed using Spearman's rank-order correlation. Oesophageal adenocarcinoma cell lines showed varying cytotoxicity in response to tamoxifen. The ER species ERα90, ERα50, and ERα46, as well as p53, were positively associated with a cytotoxic response. Conversely, ERα74, ERα70, and ERß54 were associated with a lack of cytotoxic response. The ER species detected in oesophageal adenocarcinoma cells may work together to confer sensitivity to ER modulators in this disease, which could open up a new avenue for therapy in selected patients.

Oestrogen receptors: A potential therapeutic target in oesophageal adenocarcinoma?

Oesophageal cancer is the seventh most common cancer in the world and adenocarcinoma is the dominant subtype in Western industrialised nations. The global 5-year relative survival rate for oesophageal adenocarcinoma is 12%. Chemotherapy is a standard treatment offered to patients with both resectable and unresectable disease. However, there are only a few established chemotherapeutic drug options and progress in this area is limited. Recent efforts have focused on targeted molecular therapies. Epidemiological evidence points towards hormonal influences on disease development, particularly sex hormones. Several research studies have demonstrated oestrogen receptor (ER) expression in oesophageal adenocarcinoma tissue, making them a possible option for targeting with ER modulating agents. ERs are also present in laboratory models of the disease and experiments in ER-positive cell lines suggest that ER modulator therapy may be effective. A deeper understanding of the roles of ERα and ERß in this disease would be valuable for future translation into clinical practice. In this review, we discuss the association between oestrogens and the development of oesophageal adenocarcinoma and the potential to modulate ER signalling networks for therapeutic benefit.

Mutant p53 Mediates Sensitivity to Cancer Treatment Agents in Oesophageal Adenocarcinoma Associated with MicroRNA and SLC7A11 Expression.

TP53 gene mutations occur in 70% of oesophageal adenocarcinomas (OACs). Given the central role of p53 in controlling cellular response to therapy we investigated the role of mutant (mut-) p53 and SLC7A11 in a CRISPR-mediated JH-EsoAd1 TP53 knockout model. Response to 2 Gy irradiation, cisplatin, 5-FU, 4-hydroxytamoxifen, and endoxifen was assessed, followed by a TaqMan OpenArray qPCR screening for differences in miRNA expression. Knockout of mut-p53 resulted in increased chemo- and radioresistance (2 Gy survival fraction: 38% vs. 56%, p < 0.0001) and in altered miRNA expression levels. Target mRNA pathways analyses indicated several potential mechanisms of treatment resistance. SLC7A11 knockdown restored radiosensitivity (2 Gy SF: 46% vs. 73%; p = 0.0239), possibly via enhanced sensitivity to oxidative stress. Pathway analysis of the mRNA targets of differentially expressed miRNAs indicated potential involvement in several pathways associated with apoptosis, ribosomes, and p53 signaling pathways. The data suggest that mut-p53 in JH-EsoAd1, despite being classified as non-functional, has some function related to radio- and chemoresistance. The results also highlight the important role of SLC7A11 in cancer metabolism and redox balance and the influence of p53 on these processes. Inhibition of the SLC7A11-glutathione axis may represent a promising approach to overcome resistance associated with mut-p53.

Sugar Responses of Human Enterochromaffin Cells Depend on Gut Region, Sex, and Body Mass.

Gut-derived serotonin (5-HT) is released from enterochromaffin (EC) cells in response to nutrient cues, and acts to slow gastric emptying and modulate gastric motility. Rodent studies also evidence a role for gut-derived 5-HT in the control of hepatic glucose production, lipolysis and thermogenesis, and in mediating diet-induced obesity. EC cell number and 5-HT content is increased in the small intestine of obese rodents and human, however, it is unknown whether EC cells respond directly to glucose in humans, and whether their capacity to release 5-HT is perturbed in obesity. We therefore investigated 5-HT release from human duodenal and colonic EC cells in response to glucose, sucrose, fructose and α-glucoside (αMG) in relation to body mass index (BMI). EC cells released 5-HT only in response to 100 and 300 mM glucose (duodenum) and 300 mM glucose (colon), independently of osmolarity. Duodenal, but not colonic, EC cells also released 5-HT in response to sucrose and αMG, but did not respond to fructose. 5-HT content was similar in all EC cells in males, and colonic EC cells in females, but 3 to 4-fold higher in duodenal EC cells from overweight females (p < 0.05 compared to lean, obese). Glucose-evoked 5-HT release was 3-fold higher in the duodenum of overweight females (p < 0.05, compared to obese), but absent here in overweight males. Our data demonstrate that primary human EC cells respond directly to dietary glucose cues, with regional differences in selectivity for other sugars. Augmented glucose-evoked 5-HT release from duodenal EC is a feature of overweight females, and may be an early determinant of obesity.

Metformin-induced glucagon-like peptide-1 secretion contributes to the actions of metformin in type 2 diabetes.

BACKGROUND: Metformin reduces plasma glucose and has been shown to increase glucagon-like peptide 1 (GLP-1) secretion. Whether this is a direct action of metformin on GLP-1 release, and whether some of the glucose-lowering effect of metformin occurs due to GLP-1 release, is unknown. The current study investigated metformin-induced GLP-1 secretion and its contribution to the overall glucose-lowering effect of metformin and underlying mechanisms in patients with type 2 diabetes. METHODS: Twelve patients with type 2 diabetes were included in this placebo-controlled, double-blinded study. On 4 separate days, the patients received metformin (1,500 mg) or placebo suspended in a liquid meal, with subsequent i.v. infusion of the GLP-1 receptor antagonist exendin9-39 (Ex9-39) or saline. During 240 minutes, blood was sampled. The direct effect of metformin on GLP-1 secretion was tested ex vivo in human ileal and colonic tissue with and without dorsomorphin-induced inhibiting of the AMPK activity. RESULTS: Metformin increased postprandial GLP-1 secretion compared with placebo (P = 0.014), and the postprandial glucose excursions were significantly smaller after metformin + saline compared with metformin + Ex9-39 (P = 0.004). Ex vivo metformin acutely increased GLP-1 secretion (colonic tissue, P < 0.01; ileal tissue, P < 0.05), but the effect was abolished by inhibition of AMPK activity. CONCLUSIONS: Metformin has a direct and AMPK-dependent effect on GLP-1-secreting L cells and increases postprandial GLP-1 secretion, which seems to contribute to metformin's glucose-lowering effect and mode of action. TRIAL REGISTRATION: NCT02050074 (https://clinicaltrials.gov/ct2/show/NCT02050074). FUNDING: This study received grants from the A.P. Møller Foundation, the Novo Nordisk Foundation, the Danish Medical Association research grant, the Australian Research Council, the National Health and Medical Research Council, and Pfizer Inc.

Augmented capacity for peripheral serotonin release in human obesity.

BACKGROUND/OBJECTIVES: Evidence from animal studies highlights an important role for serotonin (5-HT), derived from gut enterochromaffin (EC) cells, in regulating hepatic glucose production, lipolysis and thermogenesis, and promoting obesity and dysglycemia. Evidence in humans is limited, although elevated plasma 5-HT concentrations are linked to obesity. SUBJECTS/METHODS: We assessed (i) plasma 5-HT concentrations before and during intraduodenal glucose infusion (4 kcal/min for 30 min) in non-diabetic obese (BMI 44 ± 4 kg/m2, N = 14) and control (BMI 24 ± 1 kg/m2, N = 10) subjects, (ii) functional activation of duodenal EC cells (immunodetection of phospho-extracellular related-kinase, pERK) in response to glucose, and in separate subjects, (iii) expression of tryptophan hydroxylase-1 (TPH1) in duodenum and colon (N = 39), and (iv) 5-HT content in primary EC cells from these regions (N = 85). RESULTS: Plasma 5-HT was twofold higher in obese than control responders prior to (P = 0.025), and during (iAUC, P = 0.009), intraduodenal glucose infusion, and related positively to BMI (R2 = 0.334, P = 0.003) and HbA1c (R2 = 0.508, P = 0.009). The density of EC cells in the duodenum was twofold higher at baseline in obese subjects than controls (P = 0.023), with twofold more EC cells activated by glucose infusion in the obese (EC cells co-expressing 5-HT and pERK, P = 0.001), while the 5-HT content of EC cells in duodenum and colon was similar; TPH1 expression was 1.4-fold higher in the duodenum of obese subjects (P = 0.044), and related positively to BMI (R2 = 0.310, P = 0.031). CONCLUSIONS: Human obesity is characterized by an increased capacity to produce and release 5-HT from the proximal small intestine, which is strongly linked to higher body mass, and glycemic control. Gut-derived 5-HT is likely to be an important driver of pathogenesis in human obesity and dysglycemia.

Mechanisms Controlling Glucose-Induced GLP-1 Secretion in Human Small Intestine.

Intestinal glucose stimulates secretion of the incretin hormone glucagon-like peptide 1 (GLP-1). The mechanisms underlying this pathway have not been fully investigated in humans. In this study, we showed that a 30-min intraduodenal glucose infusion activated half of all duodenal L cells in humans. This infusion was sufficient to increase plasma GLP-1 levels. With an ex vivo model using human gut tissue specimens, we showed a dose-responsive GLP-1 secretion in the ileum at ≥200 mmol/L glucose. In ex vivo tissue from the duodenum and ileum, but not the colon, 300 mmol/L glucose potently stimulated GLP-1 release. In the ileum, this response was independent of osmotic influences and required delivery of glucose via GLUT2 and mitochondrial metabolism. The requirement of voltage-gated Na+ and Ca2+ channel activation indicates that membrane depolarization occurs. KATP channels do not drive this, as tolbutamide did not trigger release. The sodium-glucose cotransporter 1 (SGLT1) substrate α-MG induced secretion, and the response was blocked by the SGLT1 inhibitor phlorizin or by replacement of extracellular Na+ with N-methyl-d-glucamine. This is the first report of the mechanisms underlying glucose-induced GLP-1 secretion from human small intestine. Our findings demonstrate a dominant role of SGLT1 in controlling glucose-stimulated GLP-1 release in human ileal L cells.

Endoscopic cyst-gastrostomy for pancreatic pseudocysts: refining the indications.

BACKGROUND: Pseudocysts are a common consequence of acute pancreatitis and require intervention if symptomatic. Endoscopic management is emerging as a safe and effective alternative to surgery, although its use is not yet widespread. METHODS: We describe our experience of 10 consecutive unselected patients who underwent endoscopic ultrasound-guided cyst-gastrostomy and stent insertion at a tertiary referral centre. Technical aspects of the procedure are detailed with accompanying photographs. RESULTS: Six patients made an uneventful recovery. Four patients developed complications, of which one was successfully salvaged by endoscopy and three required surgery. CONCLUSION: We discuss technical and patient factors which may have contributed to these complications in the context of current literature, and in particular, found that the presence of necrosis was associated with higher morbidity, both in our series and in others. In our experience, endoscopic ultrasound-guided cyst-gastrostomy is best employed in simple, mature pseudocysts without necrotic debris, and we recommend this procedure only after a detailed assessment of the pseudocyst in a specialist hepatobiliary unit.

Androgens and esophageal cancer: What do we know?

Significant disparities exist between genders for the development and progression of several gastro-intestinal (GI) diseases including cancer. Differences in incidence between men vs women for colon, gastric and hepatocellular cancers suggest a role for steroid sex hormones in regulation of GI carcinogenesis. Involvement of intrinsic gender-linked mechanisms is also possible for esophageal adenocarcinoma as its incidence is disproportionally high among men. However, the cause of the observed gender differences and the potential role of androgens in esophageal carcinogenesis remains unclear, even though the cancer-promoting role of androgen receptors (AR) shown in other cancers such as prostate and bladder suggests this aspect warrants exploration. Several studies have demonstrated expression of ARs in esophageal cancer. However, only one study has suggested a potential link between AR signaling and outcome - poorer prognosis. Two groups have analyzed data from cohorts with prostate cancer and one of these found a decreased incidence of esophageal squamous and adenocarcinoma after androgen deprivation therapy. However, very limited information is available about the effects of androgen and AR-initiated signaling on esophageal cancer cell growth in vitro and in vivo. Possible mechanisms for androgens/AR involvement in the regulation of esophageal cancer growth are considered, and the potential use of AR as a prognostic factor and clinical target is highlighted, although insufficient evidence is available to support clinical trials of novel therapies. As esophageal adenocarcinoma is a gender linked cancer with a large male predominance further studies are warranted to clarify the role of androgens and ARs in shaping intracellular signaling and genomic responses in esophageal cancer.

Caecal tumor biopsy with a rigid sigmoidoscope - Ileorectal intussusception.

INTRODUCTION: Ileorectal intussusception is a rare condition in adults in which the distal ileum, caecum, variable lengths of ascending and transvers colon, and associated mesentery invaginate into the rectum. PRESENTATION OF CASE: We present the case of a 56 year old man who presented to our hospital for investigation of vague symptoms including small volumes of bright red rectal bleeding and colicky abdominal pain. He was found on CT scanning to have an extensive ileorectal intussusception and extensive liver metastasis. An emergency laparotomy was performed due to the concern of bowel ischaemia. No evidence of bowel ischaemia was found. The intussusceptum was carefully reduced and an extended right hemicolectomy with a primary anastomosis was performed. The patient recovered well and was discharged home six days post operatively. DISCUSSION: Intussusceptions are rare in the adult population. They may not present with the classical triad of crampy abdominal pain, vomiting, and bloody stools and radiological imaging plays a key role in diagnosis. Intussusception in adults is usually secondary to malignancy and operative management needs to take into account the risk of upstaging the disease. In the face of pre-existing metastasis, preserving bowel length should be considered; however, there is no high level evidence to guide decision-making. CONCLUSION: Intussusception is a diagnosis that needs to be considered in the adult population. Diagnosis largely depends on radiological imaging, especially CT scanning. The operative management is variable and should be determined on a case by case basis.

Colorectal cancer surgery 2000-2008: evaluation of a prospective database.

BACKGROUND: Colorectal cancer is a common cause of cancer death in Australia and is primarily managed operatively. Surgical databases are valuable in monitoring performance in cancer treatment and detecting problems and trends. METHODS: Diagnostic and treatment variables and short-term outcomes were gathered prospectively for patients undergoing resection for colorectal cancer over a 9-year period. Survival data were obtained by linkage to state and interstate death indices. RESULTS: Eight hundred and five patients underwent resection for colorectal cancer during the study period. Overall 5-year survival was 61%. Five-year cancer-specific survival was 73%. Five-year cancer-specific survival for Australian Clinico-Pathological Staging (ACPS) stages A, B, C and D was 96, 80, 61 and 19%, respectively (P < 0.0001). Emergency presentations showed diminished survival (59% versus 75%, P < 0.0001) after controlling for age and stage (hazard ratio (HR) 1.78, P= 0.005), as did transfusion recipients (63% versus 74%, P= 0.0014; HR 1.78, P= 0.004). Anastomotic leak did not affect survival in multivariable analysis. Non-cancer causes accounted for 26% deaths, primarily comprising cardiovascular deaths in the elderly. DISCUSSION: High case ascertainment, data completeness and accuracy can be obtained with prospective, independently gathered data linked electronically to national death records. Survival for colorectal cancer in South Australia continues to improve. Close follow-up for disease recurrence is warranted for transfusion recipients, emergencies and advanced disease. Locally managed databases with linkage to state registries and other institutions are powerful methods to improve data quality and surgical care at a national level.

Pseudomonas arthropathy in an older patient.

BACKGROUND: septic arthritis caused by Pseudomonas aeruginosa is uncommon in the immunocompetent older population, despite its occurrence in younger patients with open injuries and in intravenous drug abusers. CASE REPORT: here we report a case of septic arthritis caused by P. aeruginosa complicated by death in an older patient with recently treated Pseudomonas urinary tract infection. DISCUSSION: the diagnosis of Pseudomonas septic arthritis is made on culturing the organism from synovial fluid aspirate. Concurrent septic arthritis and crystal arthropathy is associated with a high mortality.