ca-074-methyl-ester and Breast-Neoplasms

Cathepsin B (CTSB) is a lysosomal protease, and several human cancers are reported highly expressing CTSB. Many optical methods have been developed for CTSB detection but not a bioluminescence (BL) probe. Herein, a CTSB-specific bioluminescence probe

Topics: Animals; Biomarkers, Tumor; Breast Neoplasms; Cathepsin B; Cell Line, Tumor; Diagnostic Imaging; Dipeptides; Female; Gene Expression; Heterografts; Humans; Luminescent Measurements; Lysosomes; Mice; Mice, Inbred BALB C; Mice, Nude; Molecular Probes

The expression of the cysteine protease cathepsin B is increased in early stages of human breast cancer.To assess the potential role of cathepsin B in premalignant progression of breast epithelial cells, we employed a 3D reconstituted basement membrane overlay culture model of MCF10A human breast epithelial cells and isogenic variants that replicate the in vivo phenotypes of hyper plasia(MCF10AneoT) and atypical hyperplasia (MCF10AT1). MCF10A cells developed into polarized acinar structures with central lumens. In contrast, MCF10AneoT and MCF10AT1 cells form larger structures in which the lumens are filled with cells. CA074Me, a cell-permeable inhibitor selective for the cysteine cathepsins B and L,reduced proliferation and increased apoptosis of MCF10A, MCF10AneoT and MCF10AT1 cells in 3D culture. We detected active cysteine cathepsins in the isogenic MCF10 variants in 3D culture with GB111, a cell-permeable activity based probe, and established differential inhibition of cathepsin B in our 3D cultures. We conclude that cathepsin B promotes proliferation and premalignant progression of breast epithelial cells. These findings are consistent with studies by others showing that deletion of cathepsin B in the transgenic MMTV-PyMT mice, a murine model that is predisposed to development of mammary cancer, reduces malignant progression.

Topics: Apoptosis; Breast; Breast Neoplasms; Cathepsin B; Cathepsin L; Cell Culture Techniques; Cell Line, Tumor; Cell Survival; Cell Transformation, Neoplastic; Cysteine Proteinase Inhibitors; Dipeptides; Disease Progression; Epithelial Cells; Female; Humans; Leucine; Models, Biological