Microbial dysbiosis and polyamine metabolism as predictive markers for early detection of pancreatic cancer.

The lack of tools for early detection of pancreatic ductal adenocarcinoma (PDAC) is directly correlated with the abysmal survival rates in patients. In addition to several potential detection tools under active investigation, we tested the gut microbiome and its metabolic complement as one of the earliest detection tools that could be useful in patients at high risk for PDAC. We used a combination of 16s rRNA pyrosequencing and whole-genome sequencing of gut fecal microbiota in a genetically engineered PDAC murine model (KRASG12DTP53R172HPdxCre or KPC). Metabolic reconstruction of microbiome was done using the HUMAnN2 pipeline. Serum polyamine levels were measured from murine and patient samples using chromogenic assay. Our results showed a Proteobacterial and Firmicutes dominance in gut microbiota in early stages of PDAC development. Upon in silico reconstruction of active metabolic pathways within the altered microbial flora, polyamine and nucleotide biosynthetic pathways were significantly elevated. These metabolic products are known to be actively assimilated by the host and eventually utilized by rapidly dividing cells for proliferation validating their importance in the context of tumorigenesis. In KPC mice, as well as PDAC patients, we show significantly elevated serum polyamine concentrations. Therefore, at the early stages of tumorigenesis, there is a strong correlation between microbial changes and release of metabolites that foster host tumorigenesis, thereby fulfilling the 'vicious cycle hypothesis' of the role of microbiome in health and disease states. Our results provide a potential, precise, noninvasive tool for early detection of PDAC, which may result in improved outcomes.

Mendez R ，Kesh K ，Arora N ，Di Martino L ，McAllister F ，Merchant N ，Banerjee S ，Banerjee S ... -  《-》

Glucose metabolism during tumorigenesis in the genetic mouse model of pancreatic cancer.

Pasquale V ，Dugnani E ，Liberati D ，Marra P ，Citro A ，Canu T ，Policardi M ，Valla L ，Esposito A ，Piemonti L ... -  《-》

Microbiota Alterations and Their Association with Oncogenomic Changes in Pancreatic Cancer Patients.

Sammallahti H ，Kokkola A ，Rezasoltani S ，Ghanbari R ，Asadzadeh Aghdaei H ，Knuutila S ，Puolakkainen P ，Sarhadi VK ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

Alterations of the bile microbiome is associated with progression-free survival in pancreatic ductal adenocarcinoma patients.

Patients with pancreatic ductal adenocarcinoma (PDAC) display an altered oral, gastrointestinal, and intra-pancreatic microbiome compared to healthy individuals. However, knowledge regarding the bile microbiome and its potential impact on progression-free survival in PDACs remains limited. Patients with PDAC (n = 45), including 20 matched pairs before and after surgery, and benign controls (n = 16) were included prospectively. The characteristics of the microbiomes of the total 81 bile were revealed by 16  S-rRNA gene sequencing. PDAC patients were divided into distinct groups based on tumor marker levels, disease staging, before and after surgery, as well as progression free survival (PFS) for further analysis. Disease diagnostic model was formulated utilizing the random forest algorithm. PDAC patients harbor a unique and diverse bile microbiome (PCoA, weighted Unifrac, p = 0.038), and the increasing microbial diversity is correlated with dysbiosis according to key microbes and microbial functions. Aliihoeflea emerged as the genus displaying the most significant alteration among two groups (p < 0.01). Significant differences were found in beta diversity of the bile microbiome between long-term PFS and short-term PFS groups (PCoA, weighted Unifrac, p = 0.005). Bacillota and Actinomycetota were identified as altered phylum between two groups associated with progression-free survival in all PDAC patients. Additionally, we identified three biomarkers as the most suitable set for the random forest model, which indicated a significantly elevated likelihood of disease occurrence in the PDAC group (p < 0.0001). The area under the receiver operating characteristic (ROC) curve reached 80.8% with a 95% confidence interval ranging from 55.0 to 100%. Due to the scarcity of bile samples, we were unable to conduct further external verification. PDAC is characterized by an altered microbiome of bile ducts. Biliary dysbiosis is linked with progression-free survival in all PDACs. This study revealed the alteration of the bile microbiome in PDACs and successfully developed a diagnostic model for PDAC.

Jiang H ，Tian Y ，Xu L ，Chen X ，Huang Y ，Wu J ，Wang T ，Liu T ，Wu X ，Ye C ，Wu H ，Ye W ，Fang L ，Zhang Y ... -  《BMC MICROBIOLOGY》

Zeb1 in Stromal Myofibroblasts Promotes Kras-Driven Development of Pancreatic Cancer.

The transcription factor Zeb1 has been identified as a crucial player in Kras-dependent oncogenesis. In pancreatic ductal adenocarcinoma (PDAC), Zeb1 is highly expressed in myofibroblasts and correlates with poor prognosis. As Kras mutations are key drivers in PDAC, we aimed here to assess the necessity of Zeb1 for Kras-driven PDAC and to define the role of Zeb1-expressing myofibroblasts in PDAC development. Genetically engineered mice with conditional pancreatic KrasG12D and Trp53 mutations (KPC) were crossed with Zeb1 haploinsufficient mice (Z+/-). Extensive PDAC was prominent in all 20-week-old KPC;Z+/+ mice, whereas only low-grade precursor lesions were detected in age-matched KPC;Z+/- littermates, with PDAC developing eventually in KPC;Z+/- aged animals. Zeb1 expression in myofibroblasts occurred early in tumorigenesis and Zeb1 haploinsufficiency retarded native expansion of stromal myofibroblasts during precursor-to-cancer progression. Zeb1 downregulation in mPSC repressed their activated gene profile, impaired their migratory and proliferative activity, and attenuated their tumor-supporting features. Conditioned media from Z+/+ mouse-activated (myofibroblast-like) pancreatic stellate cells (mPSC) boosted Ras activity in pancreatic cancer cells carrying mutant Kras; this effect was not observed when using conditioned media from Z+/- mPSC, revealing a paracrinal cooperative axis between Zeb1-expressing PSC and oncogenic Kras-bearing tumor cells. We conclude that Zeb1-expressing stromal myofibroblasts enable a heterotypic collaboration with the Kras-fated epithelial compartment, thus supporting pancreatic malignancy.Significance: Zeb1 expression in stromal myofibroblasts supports PDAC development via collaboration with the epithelial compartment bearing oncogenic Kras mutations. Cancer Res; 78(10); 2624-37. ©2018 AACR.

Sangrador I ，Molero X ，Campbell F ，Franch-Expósito S ，Rovira-Rigau M ，Samper E ，Domínguez-Fraile M ，Fillat C ，Castells A ，Vaquero EC ... -  《-》