Abstract

Mucinous cancers are characterized by tumor gland cells secreting copious amounts of mucus that forms gel-like structures. Pseudomyxoma peritonei (PMP), a rare yet prototypical mucinous malignancy, exemplifies this pathology. Biologically inert mucus coats tumor cells, promoting colonization, immune evasion, and chemoresistance. Pathological mucus accumulation leads to intra-abdominal hypertension, refractory abdominal pain, abdominal adhesions, and intestinal obstruction because of the lack of rapid, efficient, and safe clinical strategies for mucin clearance. Current management relies on extensive cytoreductive surgery to excise tumor masses and adherent mucus. Here, we present an integrated workflow spanning intestinal probiotic protease discovery for the development of mucolytic therapy. By cultivating Bacteroides thetaiotaomicron ( B. theta ) with PMP-derived mucus as the sole nutrient source, we identified its intrinsic mucolytic capacity. Crucially, transcriptomic analysis revealed that B. theta orchestrates mucus degradation via the PULs gene cluster, with concomitant upregulation of the M60 family metalloproteinases BT4244, BT3015, and BT4272. Functional validation classified these enzymes as “mucinases” responsible for tumor-associated mucin cleavage and mucolysis. Our study provides a foundation for enzyme-targeted PMP therapy, offering a paradigm shift toward minimally invasive, high-efficacy mucolysis. Our findings highlight the translational potential of microbial proteases in addressing clinical challenges posed by mucinous malignancies.