Methyl sulfone manifests anticancer activity in a metastatic murine breast cancer cell line and in human breast cancer tissue--part I: murine 4T1 (66cl-4) cell line.

Background: The spread of cancer (metastasis) is usually associated with death. We have identified a new approach that may be useful for treating metastatic cancer.

Methods: Here we studied the murine breast cancer cell line 66cl-4, because these cells are highly aggressive, potent inducers of metastasis and estrogen receptor negative.

Results: We found that 200 mM methyl sulfone did not induce apoptosis in cancerous cells but instead decreased cell proliferation and DNA synthesis, inhibited migration of cells through an extracellular matrix and induced contact inhibition and anchorage-dependent growth. Methyl sulfone promoted proper wound healing, reversed the epithelial to mesenchymal transition associated with metastatic disease and increased expression of α-smooth muscle actin, a differentiation protein of breast myoepithelial cells.

Conclusion: Methyl sulfone did not kill the cancer cells but instead decreased metastatic phenotypes and increased normal differentiated phenotypes.