Renal NF-κB activation impairs uric acid homeostasis to promote tumor-associated mortality independent of wasting

Tumor-induced host wasting and mortality are general phenomena across species. Many groups have previously demonstrated endocrinal impacts of malignant tumors on host wasting in rodents and Drosophila. Whether and how environmental factors and host immune response contribute to tumor-associated host wasting and survival, however, are largely unknown. Here, we report that flies bearing malignant yki(3SA)-gut tumors exhibited the exponential increase of commensal bacteria, which were mostly acquired from the environment, and systemic IMD-NF-kappa B activation due to suppression of a gut antibacterial amidase PGRP-SC2. Either gut microbial elimination or specific IMD-NF-kappa B blockade in the renal-like Malpighian tubules potently improved mortality of yki(3SA)-tumor-bearing flies in a manner independent of host wasting. Wefurther indicate that renal IMD-NF-kappa B activation caused uric acid (UA) overload to reduce survival of tumor-bearing flies. Therefore, our results uncover a fundamental mechanism whereby gut commensal dysbiosis, renal immune activation, and UA imbalance potentiate tumor-associated host death.

Automated summary

This study reveals a fundamental mechanism linking gut commensal dysbiosis, renal immune activation, and uric acid imbalance in tumor-associated host death. Flies with malignant gut tumors showed an exponential increase in commensal bacteria and systemic immune activation, leading to suppression of a gut antibacterial enzyme. Eliminating gut microbiota or blocking specific immune activation pathways dramatically improved the survival of tumor-bearing flies, independent of host wasting.