Pancreatic cancer prognosis is predicted by an ATAC-array technology for assessing chromatin accessibility.

Unlike other malignancies, therapeutic options in pancreatic ductal adenocarcinoma (PDAC) are largely limited to cytotoxic chemotherapy without the benefit of molecular markers predicting response. Here we report tumor-cell-intrinsic chromatin accessibility patterns of treatment-naïve surgically resected PDAC tumors that were subsequently treated with (Gem)/Abraxane adjuvant chemotherapy. By ATAC-seq analyses of EpCAM+ PDAC malignant epithelial cells sorted from 54 freshly resected human tumors, we show here the discovery of a signature of 1092 chromatin loci displaying differential accessibility between patients with disease free survival (DFS) < 1 year and patients with DFS > 1 year. Analyzing transcription factor (TF) binding motifs within these loci, we identify two TFs (ZKSCAN1 and HNF1b) displaying differential nuclear localization between patients with short vs. long DFS. We further develop a chromatin accessibility microarray methodology termed "ATAC-array", an easy-to-use platform obviating the time and cost of next generation sequencing. Applying this methodology to the original ATAC-seq libraries as well as independent libraries generated from patient-derived organoids, we validate ATAC-array technology in both the original ATAC-seq cohort as well as in an independent validation cohort. We conclude that PDAC prognosis can be predicted by ATAC-array, which represents a low-cost, clinically feasible technology for assessing chromatin accessibility profiles.

CD44 targeting reduces tumour growth and prevents post-chemotherapy relapse of human breast cancers xenografts.

CD44 is a marker of tumour-initiating cells and is upregulated in invasive breast carcinoma; however, its role in the cancer progression is unknown. Here, we show that antibody-mediated CD44-targeting in human breast cancer xenografts (HBCx) significantly reduces tumour growth and that this effect is associated to induction of growth-inhibiting factors. Moreover, treatment with this antibody prevents tumour relapse after chemotherapy-induced remission in a basal-like HBCx.

[Can the protein concentration of the ascitic fluid in ascites predict the occurrence of an infection?]. / La concentration des protides dans l'ascite permet-elle de prévoir la survenue d'une infection du liquide d'ascite?

In cirrhotic patients, spontaneous bacterial peritonitis is frequent and severe. This study was performed to determine if low protein concentration in ascitic fluid on admission could predict the occurrence of spontaneous bacterial peritonitis during hospitalization. Ninety-two cirrhotic patients with ascites, without spontaneous bacterial peritonitis were studied. Bacteriologic study and cultures of ascitic fluid were performed on admission and repeated every 5 days, and if any suspicion of infection occurred; 11 patients developed spontaneous bacterial peritonitis during hospitalization. Among the 92 patients in the study, protein concentration in ascitic fluid was initially less than 10 g/l in 45 and 10 of these 45 patients (22 p. 100) developed spontaneous bacterial peritonitis during hospitalization; protein concentration in ascitic fluid was initially greater than 10 g/l in 47 patients; only one of these 47 patients (2.1 p. 100) developed spontaneous bacterial peritonitis during hospitalization. This difference (22 p. 100 vs 2.1 p. 100) was significant (p less than 0.01). Ascitic fluid protein concentration (6.9 +/- 2.3 g/l) was significantly lower (p less than 0.01) in the spontaneous bacterial peritonitis group than in patients without peritonitis (13.8 +/- 10.5 g/l). These results suggest that: 1) ascitic fluid protein concentration on admission is lower in patients who will develop spontaneous bacterial peritonitis during hospitalization than in patients without infection and 2) patients with ascitic fluid protein concentration under 10 g/l on admission represent an high risk group for spontaneous bacterial peritonitis.

Production of an extracellular trypsin-like protease by the fungal plant pathogen Verticillium dahliae.

The plant pathogenic fungus Verticillium dahliae produced extracellular alkaline protease activity when grown in liquid medium supplemented with a protein source. A serine protease was purified 80-fold in a single step, using cation-exchange chromatography, from the filtrate of cultures grown with skim milk as a protein source. N-terminal amino acid sequence analysis of the 30-kDa protein (VDP30) that copurified with the serine protease activity suggested that VDP30 is a trypsin-like protein. The purified enzyme hydrolyzed the synthetic substrate N alpha-benzoyl-DL-arginine p-nitroanilide hydrochloride (BAPNA), and the activity on BAPNA was inhibited by leupeptin, further verifying the trypsin-like nature of the enzyme.