James L. Alexander

A radioattenuated Leishmania major vaccine markedly increases the resistance of CBA mice to subsequent infection with Leishmania mexicana mexicana

Vaccinating CBA mice with radioattenuated Leishmania major amastigotes but not with radioattenuated L. mexicana mexicana amastigotes rendered them highly resistant to subsequent infection with L. m. mexicana. Unvaccinated CBA mice were highly susceptible to infection with L. m. mexicana producing rapidly growing non-ulcerating cutaneous lesions. Two manifestations of resistance were induced in vaccinated animals depending on the timing of the challenge infection: no lesions appeared at the site of subcutaneous challenge in animals vaccinated four or more weeks previously, while lesions grew rapidly but ulcerated and healed in animals vaccinated less than 3 weeks beforehand. L. major amastigotes were found to be markedly more resistant to gamma irradiation than L. m. mexicana amastigotes both as measured by their ability to infect susceptible strains of mice and to transform and multiply as promastigotes in NNN medium.

In Vivo Endoscopic Tissue Identification by Rapid Evaporative Ionization Mass Spectrometry (REIMS)

Gastrointestinal cancers are a leading cause of mortality, accounting for 23 % of cancer-related deaths worldwide. In order to improve outcomes from these cancers, novel tissue characterization methods are needed to facilitate accurate diagnosis. Rapid evaporative ionization mass spectrometry (REIMS) is a technique developed for the in vivo classification of human tissue through mass spectrometric analysis of aerosols released during electrosurgical dissection. This ionization technique was further developed by utilizing surface induced dissociation and was integrated with an endoscopic polypectomy snare to allow in vivo analysis of the gastrointestinal tract. We tested the classification performance of this novel endoscopic REIMS method in vivo. It was shown to be capable of differentiating between healthy layers of the intestinal wall, cancer, and adenomatous polyps based on the REIMS fingerprint of each tissue type in vivo.

Leishmania mexicana: Inhibition and stimulation of phagosome—lysosome fusion in infected macrophages

Abstract The polyanionic compound poly- d -glutamic acid was found to inhibit significantly the fusion of secondary lysosomes to phagosomes containing Leishmania mexicana mexicana amastigotes for at least 96 hr. This process was viewed both by dark-field vital fluorescence microscopy and transmission electron microscopy. In poly- d -glutamic acid-treated macrophages parasites multiplied at a significantly greater rate than in untreated macrophages. Conversely, the secondary amine chloroquine caused a marked reduction in parasite growth. When L. m. mexicana promastigotes were substituted for amastigotes these results were strikingly more pronounced.

A Prospective Multi-National Study of the Colorectal Cancer Mucosal Microbiome Reveals Specific Taxonomic Changes Indicative of Disease Stage and Prognosis

Introduction The colorectal cancer (CRC) microbiome is niche specific and individualised. Several putative driver organisms enriched on CRCs have been identified from human studies, but few data exist which properly account for important clinical variables in CRC. In this study, we used a meta-taxonomic approach to demonstrate how the CRC microbiome varies with disease stage, histological markers of prognosis and host molecular phenotypes. Method A prospective study was performed on patients undergoing colonoscopy and elective surgery for CRC at three hospitals in UK and Czech Republic. Tissue was sampled from tumours, adenomas, adjacent normal mucosa and mucosa from healthy colon controls. The V1-2 regions of the 16S rRNA gene were sequenced (Illumina MiSeq); data were processed in Mothur and analysed in Stamp and R. Species assignment was performed with NCBI BLAST for microbial genomes. False discovery rate p value correction accounted for multiple testing. Histological analysis and tumour molecular phenotyping were performed according to Royal College of Pathology guidelines. Results One hundred and ninety six patients were recruited: 158 CRC patients, 24 adenoma patients and 14 normal colon controls (median age 70; range 35–90). Tumours were staged as 6 T0, 4 T1, 23 T2, 97 T3, 27 T4; 99 N0, 40 N1, 27 N2; 6 M1. No significant differences were seen in diversity or taxonomy between the UK and Czech cohorts. Adenoma and healthy colon control samples were taxonomically indistinct. However, CRCs were characterised by reduced Shannon diversity (p Conclusion This large prospective analysis demonstrates that the CRC microbiome is stage-specific and appears to evolve with disease progression. We conclude that oral pathobionts which colonise advanced stage disease relate to markers of tumour prognosis, raising the possibility that they may be directly influencing tumour invasion. Disclosure of Interest None Declared

Abstract 3977: iKnife: Rapid evaporative ionization mass spectrometry (REIMS) enables real-time chemical analysis of the mucosal lipidome for diagnostic and prognostic use in colorectal cancer

Background Real time electrospray ionization mass spectrometry (REIMS) enables detailed analysis of tumour lipid chemistry, based on real time analysis of electrocautery smoke plumes. Methods: This was a prospective, observational study performed at St. Mary9s Hospital, London, UK. Patients undergoing elective surgical resections for colorectal cancer were recruited and fresh samples were analyzed ex-vivo using a typical electrosurgery hand piece and monopolar diathermy. Sampling was performed using cutting mode with a standard generator and 30W of output power (ValleylabTM). The hand piece was modified to allow aspiration of the electrosurgical aerosol to a Xevo G2-S iKnife QTof mass spectrometer (Waters Corporation). Raw mass spectrometric data were converted to imzML format (MSConvert) and imported into MATLAB (R2014a) for pre-processing. A prospective database of healthy, dysplastic and malignant colorectal tissues was built and multivariate analysis was performed using principal component analysis and linear discriminant analysis. Classification of each individual tissue type was performed using leave-one-patient-out cross-validation. Results 40 consecutive patients were recruited (22 male, median age 68y, range 47-90). Of the 23 tumor samples 10 were rectal adenocarcinoma and 13 colonic adenocarcinoma. TNM staging of the tumour samples was as follows: T2 (8), T3 (11) T4 (4), N0 (12), N1 (6) N2 (5), M0 (22), M1 (1). Distinction of healthy and malignant colorectal tissue for the whole data set demonstrated an overall classification accuracy of 94.4% and a sensitivity of 92.4%, Specificity 96.8% (ROC AUC 0.98). The diagnostic accuracy for dysplasia was 93.7% (Specificity 95.1%, sensitivity 85.7%, AUC 0.97). Increases in glycerophospholipids (p Conclusion REIMS chemical histology provides near real time diagnostic and prognostic information for stratifying oncological and surgical therapy. Citation Format: James Macalister Kinross, Laura Muirhead, James Alexander, Julia Balog, Cristina Guallar-Hoya, Abigail Speller, Ottmar Golff, Rob Goldin, Ara Darzi, Jeremy Nicholson, Zoltan Takats. iKnife: Rapid evaporative ionization mass spectrometry (REIMS) enables real-time chemical analysis of the mucosal lipidome for diagnostic and prognostic use in colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3977.

Gut microbiota, chemotherapy and the host: the influence of the gut microbiota on cancer treatment

The gut microbiota exists in a dynamic balance between symbiosis and pathogenesis and can influence almost any aspect of host physiology. Growing evidence suggests that the gut microbiota not only plays a key role in carcinogenesis but also influences the efficacy and toxicity of anticancer therapy. The microbiota modulates the host response to chemotherapy via numerous mechanisms, including immunomodulation, xenometabolism and alteration of community structure. Furthermore, exploitation of the microbiota offers opportunities for the personalisation of chemotherapeutic regimens and the development of novel therapies. In this article, we explore the host-chemotherapeutic microbiota axis, from basic science to clinical research, and describe how it may change the face of cancer treatment.

Colorectal carcinogenesis: an archetype of gut microbiota–host interaction

Sporadic colorectal cancer (CRC) remains a major cause of worldwide mortality. Epidemiological evidence of markedly increased risk in populations that migrate to Western countries, or adopt their lifestyle, suggests that CRC is a disease whose aetiology is defined primarily by interactions between the host and his environment. The gut microbiome sits directly at this interface and is now increasingly recognised as a modulator of colorectal carcinogenesis. Bacteria such as Fusobacterium nucleatum and Escherichia coli (E. Coli) are found in abundance in patients with CRC and have been shown in experimental studies to promote neoplasia. A whole armamentarium of bacteria-derived oncogenic mechanisms has been defined, including the subversion of apoptosis and the production of genotoxins and pro-inflammatory factors. But the microbiota may also be protective: for example, they are implicated in the metabolism of dietary fibre to produce butyrate, a short chain fatty acid, which is anti-inflammatory and anti-carcinogenic. Indeed, although our understanding of this immensely complex, highly individualised and multi-faceted relationship is expanding rapidly, many questions remain: Can we define friends and foes, and drivers and passengers? What are the critical functions of the microbiota in the context of colorectal neoplasia?

Highlights from the Inaugural International Cancer Microbiome Consortium Meeting (ICMC), 5–6 September 2017, London, UK

The International Cancer Microbiome Consortium (ICMC) is a recently launched collaborative between academics and academic-clinicians that aims to promote microbiome research within the field of oncology, establish expert consensus and deliver education for academics and clinicians. The inaugural two-day meeting was held at the Royal Society of Medicine (RSM), London, UK, 5–6 September 2017. Microbiome and cancer experts from around the world first delivered a series of talks during an educational day and then sat for a day of roundtable discussion to debate key topics in microbiome-cancer research. Talks delivered during the educational day covered a broad range of microbiome-related topics. The potential role of the microbiome in the pathogenesis of colorectal cancer was discussed and debated in detail with experts highlighting the latest data in animal models and humans and addressing the question of causation versus association. The impact of the microbiota on other cancers—such as lung and urogenital tract—was also discussed. The microbiome represents a novel target for therapeutic manipulation in cancer and a number of talks explored how this might be realised through diet, faecal microbiota transplant and chemotherapeutics. On the second day, experts debated pre-agreed topics with the aim of producing a consensus statement with a focus on the current state of our knowledge and key gaps for further development. The panel debated the notion of a ‘healthy’ microbiome and, in turn, the concept of dysbiosis in cancer. The mechanisms of microbiota-induced carcinogenesis were discussed in detail and our current conceptual models were assessed. Experts also considered co-factors in microbiome-induced carcinogenesis to conclude that the tripartite ‘interactome’ between genetically vulnerable host, environment and the microbiome is central to our current understanding. To conclude, the roundtable discussed how the microbiome may be exploited for therapeutic benefit in cancer and the safety implications of performing such research in oncology patients.