Tumor-Secreted ADAMTSL4 Activates Latent TGFβ1 to Drive Cancer Cachexia.

Cancer cachexia is a devastating wasting syndrome with no approved therapies. In this study, we identify the tumor-derived glycoprotein ADAMTSL4 as a circulating factor associated with body weight loss in preclinical cachexia models and patients with colorectal and lung cancers. In mice, Adamtsl4 overexpression converted non-cachexia-inducing tumors into cachexia-inducing tumors, whereas its deletion in cachexia-inducing tumors spared fat and muscle, blunted muscle atrophy signatures, and reduced cachexia severity. ADAMTSL4 engages the latency-associated peptide (LAP) of TGFβ1, promoting local activation of TGFβ1 at muscle cell membranes. Genetic blockade of proTGFβ1 or pharmacologic inhibition of TGFβ signaling reduced ADAMTSL4-dependent wasting in adipocytes and muscle cells. Suppression of tumor-derived ADAMTSL4 attenuated skeletal muscle fibrosis in mice. Together, the association between increased circulating ADAMTSL4 levels and TGFβ-driven muscle atrophy and fibrosis gene signatures in patients with cachectic cancer identifies ADAMTSL4 as an upstream regulator of TGFβ1 and a potential therapeutic target in cancer cachexia. SIGNIFICANCE: Cancer cachexia lacks effective therapies and remains a major cause of cancer-related morbidity and mortality. We identify tumor-derived ADAMTSL4 as an upstream regulator of latent TGFβ activation via LAP engagement that promotes multiorgan wasting and fibrosis-related remodeling. Targeting ADAMTSL4 may provide a selective therapeutic strategy without systemic TGFβ pathway blockade. See related commentary by Liu and Janowitz, p. 1964.