Concurrent targeting of GSK3 and MEK as a therapeutic strategy to treat pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide. However, drug discovery for PDAC treatment has proven complicated, leading to stagnant therapeutic outcomes. Here, we identify Glycogen synthase kinase 3 (GSK3) as a therapeutic target through a whole-body genetic screening utilizing a '4-hit' Drosophila model mimicking the PDAC genotype. Reducing the gene dosage of GSK3 in a whole-body manner or knocking down GSK3 specifically in transformed cells suppressed 4-hit fly lethality, similar to Mitogen-activated protein kinase kinase (MEK), the therapeutic target in PDAC we have recently reported. Consistently, a combination of the GSK3 inhibitor CHIR99021 and the MEK inhibitor trametinib suppressed the phosphorylation of Polo-like kinase 1 (PLK1) as well as the growth of orthotopic human PDAC xenografts in mice. Additionally, reducing PLK1 genetically in 4-hit flies rescued their lethality. Our results reveal a therapeutic vulnerability in PDAC that offers a treatment opportunity for patients by inhibiting multiple targets.

Drosophila Screening Identifies Dual Inhibition of MEK and AURKB as an Effective Therapy for Pancreatic Ductal Adenocarcinoma.

Significant progress has been made in understanding the pathogenesis of pancreatic ductal adenocarcinoma (PDAC) by generating and using murine models. To accelerate drug discovery by identifying novel therapeutic targets on a systemic level, here we generated a Drosophila model mimicking the genetic signature in PDAC (KRAS, TP53, CDKN2A, and SMAD4 alterations), which is associated with the worst prognosis in patients. The '4-hit' flies displayed epithelial transformation and decreased survival. Comprehensive genetic screening of their entire kinome revealed kinases including MEK and AURKB as therapeutic targets. Consistently, a combination of the MEK inhibitor trametinib and the AURKB inhibitor BI-831266 suppressed the growth of human PDAC xenografts in mice. In patients with PDAC, the activity of AURKB was associated with poor prognosis. This fly-based platform provides an efficient whole-body approach that complements current methods for identifying therapeutic targets in PDAC. SIGNIFICANCE: Development of a Drosophila model mimicking genetic alterations in human pancreatic ductal adenocarcinoma provides a tool for genetic screening that identifies MEK and AURKB inhibition as a potential treatment strategy.

Bacteremia after hepatectomy and biliary reconstruction for biliary cancer: the characteristics of bacteremia according to occurrence time and associated complications.

PURPOSE: Bacteremia occurring after extensive hepatic resection and biliary reconstruction (Hx + Bx) for biliary cancer is a critical infectious complication. This study evaluated postoperative bacteremia and examined the potential usefulness of surveillance cultures. METHODS: We retrospectively reviewed 179 patients who underwent Hx + Bx for biliary cancer from January 2008 to December 2018 in our department. RESULTS: Bacteremia occurred in 41 (23.0%) patients. Patients with bacteremia had a longer operation time and more frequent intraoperative transfusion and more frequently developed organ/space surgical site infection (SSI) than those without bacteremia. The most frequently isolated bacterial species from blood cultures were Enterococcus faecium (29.3%), Enterobacter cloacae (24.4%), and Enterococcus faecalis (22.0%). The SIRS duration of bacteremia associated with organ/space SSI was significantly longer than that of other infectious complications (median 96 h vs. 48 h; p = 0.043). Bacteremia associated with organ/space SSI occurred most often by postoperative day (POD) 30. The concordance rate of bacterial species between blood and surveillance cultures within POD 30 was 67-82%. CONCLUSIONS: Bacteremia associated with organ/space SSI required treatment for a long time and typically occurred by POD 30. Postoperative surveillance cultures obtained during this period may be useful for selecting initial antibiotic therapy because of their high concordance rate with blood cultures.