Ryodai Yamamura

Muscle-invasive bladder cancer is molecularly heterogeneous, and the basal/squamous subtype frequently exhibits elevated EGFR expression and TP53 and RB1 alterations. Functional vulnerabilities associated with these alterations remain incompletely defined, while large-scale in vivo screening in mammalian models is experimentally demanding. Therefore, we developed a genotype-defined Drosophila melanogaster model combining Egfr overexpression, mutant p53, and Rbf suppression in Malpighian tubules. The resulting 3-hit model showed increased Malpighian tubule volume and reduced adult eclosion rate. A dominant modifier screen targeting 216 kinase genes identified 72 genes whose perturbation significantly increased the eclosion rate, and a complementary RNA interference screen identified eight kinases whose knockdown increased the eclosion rate. Among these hits, Pka-C3, which is a Drosophila ortholog of human PRKX, emerged as one of the strongest suppressors of the 3-hit phenotype. PRKX was prioritized for further study because public transcriptomic datasets showed higher PRKX expression in bladder tumors than in normal bladder tissue. PRKX knockdown reduced spheroid volume in four human bladder cancer cell lines with distinct EGFR, TP53, and RB1 profiles. Both small interfering RNAs produced significant reductions in two cell lines, whereas only one siRNA reached significance in the other two. These findings nominate PRKX as a candidate vulnerability in bladder cancer and highlight a cross-species approach that combines genotype-informed Drosophila screening with functional testing in human cancer cells to prioritize targets for further investigation.

SUMMARY: Pancreatic ductal adenocarcinoma (PDAC) is a fatal cancer characterized by limited therapeutic options and a highly treatment-resistant tumor microenvironment. Beyond tumor-intrinsic genetic alterations, growing evidence indicates that host–microbiome interactions influence cancer progression through microbial metabolites. However, how microbiome-derived metabolites influence oncogenic signaling in PDAC remains unclear. Here, integrated profiling revealed a consistent reduction of the microbial metabolite acetic acid in fecal samples from treatment-naïve patients with PDAC and in a genetically defined Drosophila model recapitulating key PDAC driver alterations. Acetic acid activates AMP-activated protein kinase, and pharmacological activation of this pathway together with inhibition of mitogen-activated protein kinase signaling suppressed tumor growth in fly and mouse models. Combined pathway targeting restored AMPK activity and suppressed cancer-associated fibroblast activation. These findings identify a microbiome-associated metabolic vulnerability in PDAC and suggest that coordinated targeting of metabolic and oncogenic signaling may restrain tumor progression and improve therapeutic strategies.

Supplementary methods, tables, and figures

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.

Background/objective: Ulcerative colitis (UC) is significantly linked with gut microbiota, which is essential for maintaining gut health. Their metabolites mitigate gut inflammation and bolster barrier function. Among these metabolites, we focused on vitamin B3, which has been reported to improve the pathogenesis of UC in mice. This study aimed to compare fecal vitamin B3 and gut microbiota between non-UC and UC patients. Methods: We assessed fecal metabolites and gut microbiota in 71 UC patients (UC group) and 72 non-UC patients (non-UC group) matched by sex and age in 10-year intervals. Fecal samples were collected and metabolites were analyzed using capillary electrophoresis time-of-flight mass spectrometry. Bacterial DNA was extracted for 16S rRNA gene sequencing. We analyzed fecal nicotinamide levels and gut microbiota composition, employing statistical adjustments for confounding factors. Results: We found that the UC group exhibited significantly lower fecal nicotinamide levels and α-diversity (Shannon index) compared to the non-UC group. The relative abundance of bacterial genera such as Treponema, UCG-002, and Fusicatenibacter was decreased, while Sellimonas, Fournierella, and Oscillospira were increased in the UC group. Moreover, a negative correlation was observed between Sellimonas abundance and fecal nicotinamide levels in the UC group. Additionally, the UC group showed higher expression of a bacterial gene encoding nicotinamidase compared to the non-UC group. Conclusions: These findings suggest that gut microbiota dysbiosis contributes to reduced vitamin B3 metabolism in UC patients. The study highlights the potential of replenishing vitamin B3 metabolic pathways as a novel therapeutic approach for UC treatment.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive cancers with limited treatment options and a poor prognosis. Recent studies have emphasized the pivotal influence of the microbiome, particularly intratumoral and gut microbial systems, in driving PDAC progression and shaping therapeutic responses. Emerging strategies for microbiome modulation, such as fecal microbiota transplantation (FMT), have demonstrated the potential in preclinical models to enhance immune responses and inhibit tumor growth. However, significant challenges including donor variability, microbiome engraftment, and suboptimal delivery methods have hindered the transition of these strategies to clinical settings. Addressing these limitations by optimizing microbiota-based therapies is essential for harnessing their full potential as adjunct treatments for PDAC. This review delves into the intricate relationship between microbiota and PDAC, evaluates the therapeutic efficacy and limitations of FMT, and outlines future research trajectories to advance this emerging field.

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.

Supplementary methods, tables, and figures