Breast cancer bone metastases often cause a debilitating incurable condition with osteolytic lesions, muscle weakness, and a high mortality. Current treatment comprises chemotherapy, irradiation, surgery, and antiresorptive drugs that restrict but do not revert bone destruction. In hormone receptor–negative breast cancer cell lines and human breast cancer tissue, we identified the expression of sclerostin, a soluble Wnt inhibitor that represses osteoblast differentiation and bone formation. In mice with breast cancer bone metastases, pharmacological inhibition of sclerostin using an anti-sclerostin antibody (Scl-Ab) reduced the metastatic burden. Furthermore, sclerostin inhibition prevented cancer-induced bone destruction by augmenting osteoblast-mediated bone formation and by reducing osteoclast-dependent bone resorption. During advanced disease, NF-κB and p38 signaling was increased in muscles in a TGF-β1–dependent manner, causing muscle fiber atrophy, muscle weakness, and tissue regeneration with an increase in Pax7-positive satellite cells. Scl-Ab treatment restored NF-κB and p38 signaling, the abundance of Pax7-positive cells, and muscle function. These effects improved the health and expanded the life span of cancer-bearing mice. Together, these results demonstrate that pharmacological inhibition of sclerostin reduces bone metastatic burden and muscle weakness, with a prolongation of survival time. This might provide novel options for treating musculoskeletal complications in breast cancer patients.
Eric Hesse, Saskia Schröder, Diana Brandt, Jenny Pamperin, Hiroaki Saito, Hanna Taipaleenmäki
Guidelines: The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. All accepted letters will be posted on our website within one week of acceptance. We reserve the right to edit any letter for length, content, and clarity. Authors of all accepted letters will be asked to preview any changes. Authors will be notified by e-mail if their letters were not accepted. As this is a final decision, no appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editors directly at firstname.lastname@example.org.