Methyl sulfone manifests anticancer activity in a metastatic murine breast cancer cell line and in human breast cancer tissue--part 2: human breast cancer tissue.

BACKGROUND Methyl sulfone is a small molecule that reverses cancerous phenotypes of a melanoma cell line. Here, we sought to determine whether methyl sulfone was effective against human breast cancer tissue. METHODS We studied normal and cancerous breast tissue obtained from 17 patients. RESULTS Methyl sulfone introduced structural order, with cancer tissue taking on the morphology of normal in vivo breast tissue; this structural order was sustainable over long-term culture. Methyl sulfone promoted proper wound healing, including migration of cells into wounded areas and establishment of stable contact inhibition once wounds were covered. Methyl sulfone decreased expression of two breast stem cell marker proteins, HCAM and OCT3/4, which are associated with aberrantly rapid migration of metastatic cells. Finally, normal and cancerous primary breast cells remained viable and healthy in methyl sulfone culture for at least 90 days. CONCLUSION Methyl sulfone reintroduced a normal structural phenotype to human breast cancer tissues.