Microbiota-derived 3-IAA influences chemotherapy efficacy in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second most deadly cancer by 2040, owing to the high incidence of metastatic disease and limited responses to treatment1,2. Less than half of all patients respond to the primary treatment for PDAC, chemotherapy3,4, and genetic alterations alone cannot explain this5. Diet is an environmental factor that can influence the response to therapies, but its role in PDAC is unclear. Here, using shotgun metagenomic sequencing and metabolomic screening, we show that the microbiota-derived tryptophan metabolite indole-3-acetic acid (3-IAA) is enriched in patients who respond to treatment. Faecal microbiota transplantation, short-term dietary manipulation of tryptophan and oral 3-IAA administration increase the efficacy of chemotherapy in humanized gnotobiotic mouse models of PDAC. Using a combination of loss- and gain-of-function experiments, we show that the efficacy of 3-IAA and chemotherapy is licensed by neutrophil-derived myeloperoxidase. Myeloperoxidase oxidizes 3-IAA, which in combination with chemotherapy induces a downregulation of the reactive oxygen species (ROS)-degrading enzymes glutathione peroxidase 3 and glutathione peroxidase 7. All of this results in the accumulation of ROS and the downregulation of autophagy in cancer cells, which compromises their metabolic fitness and, ultimately, their proliferation. In humans, we observed a significant correlation between the levels of 3-IAA and the efficacy of therapy in two independent PDAC cohorts. In summary, we identify a microbiota-derived metabolite that has clinical implications in the treatment of PDAC, and provide a motivation for considering nutritional interventions during the treatment of patients with cancer.

Parenchyma-Preserving Hepatectomy in Perihilar Cholangiocarcinoma: A Chance for Critical Patients?

Introduction: Surgery for perihilar cholangiocarcinoma (pCCA) is associated with high rates of postoperative morbidity and mortality. Extended liver resection (EXT) increases R0 resection rate and survival; however, patients with high perioperative risk are not suitable for extended resection. This study aimed to compare overall survival and surgical morbidity in patients with extended liver resection and parenchyma-preserving hepatectomy (PPH). Methods: Between January 2010 and November 2020, 113 consecutive patients with pCCA underwent surgery at our institution. Eighty-two patients were resected in curative intent. Sixty-four patients received extended liver resection, and 18 patients PPH. Outcomes of resections were evaluated. Results: There was no significant difference in overall survival in patients with PPH compared to extended liver resection (log-rank p = 0.286). Patients with PPH experienced lower rates of postoperative morbidity and mortality. There was no case of in-house mortality in PPH-resected patients compared to 10 cases (16%) in patients that received EXT (p = 0.073). Conclusion: PPH shows similar overall survival with lower rates of postoperative morbidity and mortality. Our findings support the role of a PPH, in selected patients with pCCA, that are not suitable for extended resection due to increased perioperative risk.