Introduction

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal human cancers. In recent years, bacteria resembling gut microbiota have been found within pancreatic cancer tissues, suggesting their potential influence on tumor growth and prognosis. However, the details remain insufficiently elucidated. Therefore, we clarified the characteristics of the tumor microbiota using resected pancreatic cancer specimens from our institution and to analyze their relationship with the tumor microenvironment and prognosis.

Aims & Methods

We analyzed formalin-fixed paraffin-embedded (FFPE) sections from 162 PDAC patients who underwent surgery between April 2008 and March 2017 in our institution.
DNA were extracted from FFPE using Quantitative polymerase chain reaction (qPCR) and in situ hybridization (ISH) targeting 16S rRNA. Microbial community was explored by using 16S metagenomics from FFPE. The profile of intratumoral bacteria was compared with clinical information, pathological findings including tumor-infiltrating T cells, tumor-associated macrophage, fibrosis, and alterations in four main driver genes (KRAS, TP53, CDKN2A/p16, SMAD4) in tumor genomes.

Results

Among 162 cases, 52 showed amplification in qPCR targeting 16S rRNA and positive ISH reactions targeting 16S rRNA within tumor tissues. The presence of bacteria commonly found in gut microbiota such as Proteobacteria and Firmicutes was observed within tumor tissues of these 52 cases. Comparison with paired normal tissues (N=26) revealed differences in αdiversity (P<0.01) and βdiversity (P<0.01), suggesting the presence of a unique tumor microbiota. Subsequently, we divided the 52 cases into two groups based on the median survival period. We identified one bacterial species was dominant in the long-term survival group and ten were in the long-term survival group using Linear Discriminant Analysis Effect Size. Comparison of bacterial profiles between cases with good and poor prognosis revealed a significant positive correlation between a shorter survival time and the presence of anaerobic bacteria such as Bacteroides, Lactobacillus, and Peptoniphilus. 24 cases which were positive for at least one of the three prognostic bacteria were compared with 28 cases negative for all of them, there were not signicfficant correlation with tumor size, pathological stage, fibrosis,and alterations in four main driver genes,but signicfficant correlation with the lower degree of tumor-infiltrating T cells positive for CD4, CD8, and CD45RO (P<0.01, P<0.01, P<0.01, respectively)

Conclusion

We identified multiple bacterial species within pancreatic cancer tumors associated with prognosis. Increased abundance of Bacteroides, Lactobacillus and Peptoniphilus along with the progression of pancreatic cancer suggests their involvement in worsening prognosis through tumor immunity.

Introduction

Zastaprazan is a novel potassium-competitive acid blocker (P-CAB) with fast onset and prolonged duration. This study aims to assess the efficacy and safety of zastaprazan compared to esomeprazole in patient with erosive oesophagitis.

Aims & Methods

A phase 3, multicentre, randomised, double-blind, active-controlled clinical study was conducted with 300 subjects with confirmed erosive oesophagitis (Los Angeles classification grades A to D). Subjects were randomised to receive zastaprazan 20 mg or esomeprazole 40 mg once daily up to 8 weeks. The primary endpoint was the cumulative proportion of subject with healed erosive oesophagitis confirmed by endoscopy up to week 8. The secondary endpoints included the healing rate at week 4, symptom response and quality of life. Safety profiles and serum gastrin levels were also assessed. [ClinicalTrials.gov: NCT04282954]

Results

The cumulative healing rate at week 8 were 97.9% for zastaprazan and 94.9% for esomeprazole. The difference was 2.98% (95% CI, -1.36 to 7.32, FAS). The cumulative healing rate at week 4 was 95.1% for zastaprazan and 87.7% for esomeprazole with a statistically significant difference of 7.44% (95% CI, 0.92 to 13.97, FAS) (p <0.05). The incidence of adverse events was comparable between groups, and zastaprazan was well-tolerated. Serum gastrin levels significantly increased during the treatment and declined after the treatment.

Conclusion

An 8-week therapy of zastaprazan 20 mg is non-inferior to esomeprazole 40 mg in subjects with erosive oesophagitis. The healing rate at week 4 appears to be higher for zastaprazan than esomeprazole at week 4, which further investigation is warranted. These findings suggest that zastaprazan would be a promising alternative to proton pump inhibitors for the treatment of erosive oesophagitis.

Disclosure

Funding for this clinical study was provided by Onconic Therapeutics.

Introduction

Intestinal bacteria with 7α-dehydroxylating (7αDH) activity are able to produce the secondary bile acids, such as deoxycholic acid (DCA). Higher concentrations of DCA are linked to a higher risk of colorectal cancer (CRC) risk, yet underlying molecular mechanisms demonstrating a causal role of DCA are still unclear. This includes a recently demonstrated immunomodulatory effect of secondary bile acids, which may contribute to CRC pathogenesis. Here, we aim to investigate the tumor-promoting and immunomodulatory role of DCA in a gnotobiotic CRC mouse model.

Aims & Methods

Germ-free wildtype mice were colonized with a simplified bacterial consortium, the bile acid converting microbiota (BACOMI). BACOMI is able to produce DCA due to the 7αDH activity of Clostridium scindens (+7αDH). Control mice were colonized with BACOMI without C. scindens, lacking 7αDH activity (-7αDH) and DCA. A sub-group of mice was treated with AOM/DSS to induce colonic tumors. Bacterial abundances were measured in colonic content via qPCR, cecal bile acid composition was analyzed using LC-MS/MS and colonic tissue was analyzed using qPCR and immunofluorescence-staining. Primary T-cells and macrophages were isolated from the colon as well as mesenteric and iliac lymph nodes and analyzed by flow cytometry.

Results

DCA was exclusively present in mice colonized with the BACOMI consortium and led to higher colonic tumor numbers compared to mice colonized with BACOMI without C. scindens (+7αDH = 20.5 tumors±7.5 SD vs. -7αDH = 7.9 tumors±2.0 SD), in particular for small- and medium-sized tumors. Presence of DCA also resulted in shorter colon lengths and lower levels of butyrate in cecal content. In BACOMI colonized mice, the treatment with AOM/DSS promoted colonic colonization by C. scindens compared to mice without AOM/DSS treatment. Even without AOM/DSS treatment, the presence of C. scindens and DCA resulted in significantly higher numbers of Ki67+ epithelial cells in colonic crypts and more pronounced hypoxia in the colonic epithelium. Colonic expression of genes involved in CRC pathogenesis (e.g., Axin2, Ccnd1, Myc), bile acid metabolism (e.g., Nr1h4, Nr0b2, Slc51b) as well as immune responses (e.g., Nfkb1, Rorc, Itgam) was upregulated in mice with DCA. Sub-types of Foxp3+ regulatory T-cells were more abundant in mesenteric and iliac lymph nodes whereas numbers of Ly6C high macrophages were lower in the colon and mesenteric lymph nodes of mice with DCA compared to mice lacking DCA.

Conclusion

​In a gnotobiotic mouse model for CRC, the presence of microbially-derived DCA promotes colonic tumorigenesis in vivo. Even in the absence of chemically-induced tumorigenesis, DCA stimulates the expression of markers closely associated with CRC and promotes colonic epithelial proliferation. These findings strongly imply a causal role of DCA in the development of CRC. Additionally, DCA shows immunomodulatory effects, which may demonstrate another mechanistic link of how DCA affects intestinal health.