Oliver M. Fisher

Inhibiting the system xC(-)/glutathione axis selectively targets cancers with mutant-p53 accumulation.

TP53, a critical tumour suppressor gene, is mutated in over half of all cancers resulting in mutant-p53 protein accumulation and poor patient survival. Therapeutic strategies to target mutant-p53 cancers are urgently needed. We show that accumulated mutant-p53 protein suppresses the expression of SLC7A11, a component of the cystine/glutamate antiporter, system xC−, through binding to the master antioxidant transcription factor NRF2. This diminishes glutathione synthesis, rendering mutant-p53 tumours susceptible to oxidative damage. System xC− inhibitors specifically exploit this vulnerability to preferentially kill cancer cells with stabilized mutant-p53 protein. Moreover, we demonstrate that SLC7A11 expression is a novel and robust predictive biomarker for APR-246, a first-in-class mutant-p53 reactivator that also binds and depletes glutathione in tumours, triggering lipid peroxidative cell death. Importantly, system xC− antagonism strongly synergizes with APR-246 to induce apoptosis in mutant-p53 tumours. We propose a new paradigm for targeting cancers that accumulate mutant-p53 protein by inhibiting the SLC7A11–glutathione axis.

The prognostic value of TP53 mutations in oesophageal adenocarcinoma: a systematic review and meta-analysis

Objective To clarify the prognostic role of tumour protein 53 (TP53) mutations in patients with oesophageal adenocarcinoma (OAC) as there is a need for biomarkers that assist in guiding management for patients with OAC. Design A systematic review was conducted using MEDLINE, Embase, PubMed and Current Contents Connect to identify studies published between January 1990 and February 2015 of oesophageal cancer populations (with OAC diagnoses >50% of cases) that measured tumoural TP53 status and reported hazard ratios (HR), or adequate data for estimation of HR for survival for TP53-defined subgroups. Risk of bias for HR estimates was assessed using prespecified criteria for the appraisal of relevant domains as defined by the Cochrane Prognosis Methods Group including adherence to Grading of Recommendations, Assessment, Development and Evaluation and REporting recommendations for tumor MARKer prognostic studies guidelines, as well as assay method used (direct TP53 mutation assessment vs immunohistochemistry) and adjustment for standard prognostic factors. A pooled HR and 95% CI were calculated using a random-effects model. Results Sixteen eligible studies (11 with OAC only and 5 mixed histology cohorts) including 888 patients were identified. TP53 mutations were associated with reduced survival (HR 1.48, 95% CI 1.16 to 1.90, I2=33%). A greater prognostic effect was observed in a sensitivity analysis of those studies that reported survival for OAC-only cohorts and were assessed at low risk of bias (HR 2.11, 95% CI 1.35 to 3.31, I2=0%). Conclusions Patients with OAC and TP53 gene mutations have reduced overall survival compared with patients without these mutations, and this effect is independent of tumour stage.

Novel metastatic models of esophageal adenocarcinoma derived from FLO-1 cells highlight the importance of E-cadherin in cancer metastasis

There is currently a paucity of preclinical models available to study the metastatic process in esophageal cancer. Here we report FLO-1, and its isogenic derivative FLO-1LM, as two spontaneously metastatic cell line models of human esophageal adenocarcinoma. We show that FLO-1 has undergone epithelial-mesenchymal transition and metastasizes following subcutaneous injection in mice. FLO-1LM, derived from a FLO-1 liver metastasis, has markedly enhanced proliferative, clonogenic, anti-apoptotic, invasive, immune-tolerant and metastatic potential. Genome-wide RNAseq profiling revealed a significant enrichment of metastasis-related pathways in FLO-1LM cells. Moreover, CDH1, which encodes the adhesion molecule E-cadherin, was the most significantly downregulated gene in FLO-1LM compared to FLO-1. Consistent with this, repression of E-cadherin expression in FLO-1 cells resulted in increased metastatic activity. Importantly, reduced E-cadherin expression is commonly reported in esophageal adenocarcinoma and independently predicts poor patient survival. Collectively, these findings highlight the biological importance of E-cadherin activity in the pathogenesis of metastatic esophageal adenocarcinoma and validate the utility of FLO-1 parental and FLO-1LM cells as preclinical models of metastasis in this disease.

MIC-1/GDF15 in Barrett's oesophagus and oesophageal adenocarcinoma.

Background:Biomarkers are needed to improve current diagnosis and surveillance strategies for patients with Barrett’s oesophagus (BO) and oesophageal adenocarcinoma (OAC). Macrophage inhibitory cytokine 1/growth differentiation factor 15 (MIC-1/GDF15) tissue and plasma levels have been shown to predict disease progression in other cancer types and was therefore evaluated in BO/OAC.Methods:One hundred thirty-eight patients were studied: 45 normal oesophagus (NE), 37 BO, 16 BO with low-grade dysplasia (LGD) and 40 OAC.Results:Median tissue expression of MIC-1/GDF15 mRNA was ⩾25-fold higher in BO and LGD compared to NE (P<0.001); two-fold higher in OAC vs BO (P=0.039); and 47-fold higher in OAC vs NE (P<0.001). Relative MIC-1/GDF15 tissue expression >720 discriminated between the presence of either OAC or LGD vs NE with 94% sensitivity and 71% specificity (ROC AUC 0.86, 95% CI 0.73–0.96; P<0.001). Macrophage inhibitory cytokine 1/growth differentiation factor 15 plasma values were also elevated in patients with OAC vs NE (P<0.001) or BO (P=0.015).High MIC-1/GDF15 plasma levels (⩾1140 pg ml−1) were an independent predictor of poor survival for patients with OAC (HR 3.87, 95% CI 1.01–14.75; P=0.047).Conclusions:Plasma and tissue levels of MIC-1/GDF15 are significantly elevated in patients with BO, LGD and OAC. Plasma MIC-1/GDF15 may have value in diagnosis and monitoring of Barrett’s disease.

CEA to peritoneal carcinomatosis index (PCI) ratio is prognostic in patients with colorectal cancer peritoneal carcinomatosis undergoing cytoreduction surgery and intraperitoneal chemotherapy: A retrospective cohort study

Serum tumor markers are prognostic in patients with colorectal cancer peritoneal carcinomatosis (CRPC) undergoing cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC). Assessment of the ratio of tumor marker to volume, as depicted by peritoneal carcinomatosis index (PCI), and how this may affect overall (OS) and recurrence free survival (RFS) has not been reported.

Novel Aberrations Uncovered in Barrett's Esophagus and Esophageal Adenocarcinoma Using Whole Transcriptome Sequencing

Esophageal adenocarcinoma (EAC) has one of the fastest increases in incidence of any cancer, along with poor five-year survival rates. Barretts esophagus (BE) is the main risk factor for EAC; however, the mechanisms driving EAC development remain poorly understood. Here, transcriptomic profiling was performed using RNA-sequencing (RNA-seq) on premalignant and malignant Barretts tissues to better understand this disease. Machine-learning and network analysis methods were applied to discover novel driver genes for EAC development. Identified gene expression signatures for the distinction of EAC from BE were validated in separate datasets. An extensive analysis of the noncoding RNA (ncRNA) landscape was performed to determine the involvement of novel transcriptomic elements in Barretts disease and EAC. Finally, transcriptomic mutational investigation of genes that are recurrently mutated in EAC was performed. Through these approaches, novel driver genes were discovered for EAC, which involved key cell cycle and DNA repair genes, such as BRCA1 and PRKDC. A novel 4-gene signature (CTSL, COL17A1, KLF4, and E2F3) was identified, externally validated, and shown to provide excellent distinction of EAC from BE. Furthermore, expression changes were observed in 685 long noncoding RNAs (lncRNA) and a systematic dysregulation of repeat elements across different stages of Barretts disease, with wide-ranging downregulation of Alu elements in EAC. Mutational investigation revealed distinct pathways activated between EAC tissues with or without TP53 mutations compared with Barretts disease. In summary, transcriptome sequencing revealed altered expression of numerous novel elements, processes, and networks in EAC and premalignant BE. Implications: This study identified opportunities to improve early detection and treatment of patients with BE and esophageal adenocarcinoma. Mol Cancer Res; 15(11); 1558–69. ©2017 AACR.

Changes in gene expression of neo-squamous mucosa after endoscopic treatment for dysplastic Barrett’s esophagus and intramucosal adenocarcinoma

Background Endoscopic therapy, including by radiofrequency ablation (RFA) or endoscopic mucosal resection (EMR), is first line treatment for Barrett’s esophagus (BE) with high-grade dysplasia (HGD) or intramucosal cancer (IMC) and may be appropriate for some patients with low-grade dysplasia (LGD). Objective The purpose of this study was to investigate the molecular effects of endotherapy. Methods mRNA expression of 16 genes significantly associated with different BE stages was measured in paired pre-treatment BE tissues and post-treatment neo-squamous biopsies from 36 patients treated by RFA (19 patients, 3 IMC, 4 HGD, 12 LGD) or EMR (17 patients, 4 IMC, 13 HGD). EMR was performed prior to RFA in eight patients. Normal squamous esophageal tissues were from 20 control individuals. Results Endoscopic therapy resulted in significant change towards the normal squamous expression profile for all genes. The neo-squamous expression profile was significantly different to the normal control profile for 11 of 16 genes. Conclusion Endotherapy results in marked changes in mRNA expression, with replacement of the disordered BE dysplasia or IMC profile with a more “normal” profile. The neo-squamous mucosa was significantly different to the normal control squamous mucosa for most genes. The significance of this finding is uncertain but it may support continued endoscopic surveillance after successful endotherapy.

The use of carbon dioxide insufflation to facilitate identification of intestinal injuries in patients undergoing cytoreductive surgery and intraperitoneal chemotherapy

Since Sugarbaker introduced the concept of cytoreduction (CRS) and intraperitoneal chemotherapy (IPC) in the mid 1990s, the approach to management of peritoneal metastases has drastically changed [1]. This has resulted in markedly improved outcomes for selected patients with peritoneal dissemination of many tumours including colorectal cancer and pseudomyxoma peritonei [2, 3]. The treatment necessitates radical surgical resection of macroscopically visible disease in the abdomen and pelvis and administration of intraperitoneal chemotherapy to eradicate remaining microscopic disease [4]. However, this surgical procedure harbours a level of complexity in that it combines long operative times, numerous and complex resections, peritoneal stripping and administration of heated intraperitoneal chemotherapy, all of which contribute to a degree of morbidity and mortality. Intestinal perforations, anastomotic leaks and their subsequent clinical sequelae (such as fistulae and abscesses) are amongst the most common complications associated with this radical therapy [5–7]. Reasons for this are multifactorial and involve a combination of patient, treatment and technical factors. Of particular concern are patients with extensive small and large bowel disease, requiring aggressive resection of the tumour from the bowel surface and often resulting in a mixture of serosal, seromuscular and full-thickness injuries to the bowel at multiple sites. These can be quite subtle, especially after administration of hyperthermic intraperitoneal chemotherapy (HIPEC) which results in discolouration and oedema of the intestine. Nonetheless, identification and repair of all defects contributes to reduction in bowel complications including perforations, anastomotic leaks, fistulae and abscess formation. The use of carbon dioxide (CO2) insufflation of the bowel as a method of detecting occult defects requiring repair is a novel approach. The technique was given the name ‘‘the sausage test’’ by the surgeon who pioneered its use, due to the gross appearance of bowel when insufflated and distended throughout. It is a simple, economical and effective technique which requires little more than a laparoscopic stack insufflator (our unit utilises the Olympus UHI-3 ), insufflation tubing and medical grade CO2 as would be used routinely for establishing pneumoperitoneum in a laparoscopic operation (supplementary video 1). The insufflator is set at a high flow rate with a pressure of 12–15 mmHg. The end of the tubing is fed a small way into the intestinal lumen through either the most distal or proximal enterotomy, colotomy or via the stoma if one is fashioned. A purse-string suture can be applied around the entry point of the insufflation tubing to create a seal; however, we generally find that application of gentle manual pressure at this site often suffices. The insufflation is applied to the bowel, and it is carefully and thoroughly run through its entire length and examined while distended. At sites of suspected otomy or anastomosis, the intestine distal and proximal is gently squeezed to give the CO2 a Electronic supplementary material The online version of this article (doi:10.1007/s10151-017-1644-6) contains supplementary material, which is available to authorized users.

Left Paraduodenal Hernia: A Rare Complication following Laparoscopic Appendectomy

Paraduodenal hernias are rare congenital internal hernias accounting for <2% of intestinal obstruction. Left paraduodenal hernias (LPDHs) into the fossa of Landzert are the more common type and result from abnormal rotation of the midgut and failure of peritoneal fusion. Sequelae of these hernias usually occur spontaneously in the 4th or 5th decade of life and are more common in males and have a significant risk of incarceration and subsequent strangulation. We describe a case of a 15-year-old female who develops a LPDH following laparoscopic appendectomy, resulting in jejunal incarceration and subsequent small intestinal obstruction. The patient discussed is from an atypical demographic, being young and female. In addition, the precipitating event prompting incarceration of the hernia appears to be the application of pneumoperitoneum, placement in the Trendelenburg position, and manipulation of small intestine for the purpose of facilitating laparoscopic appendectomy. To our knowledge, this is the first reported case of LPDH exacerbated by laparoscopic procedure.