Analyzing the Role of Proteases in Breast Cancer Progression and Metastasis Using Primary Cells from Transgenic Oncomice

Isolating Primary Tumor Cells from the MMTV-PyMT Mouse Model and Their Use in Developing an Orthotopic Mouse Model of Breast Cancer

To study the effect of the immunologically unimpaired microenvironment on tumor progression as well as the efficacy of therapies requiring a functioning immune system, xenograft models are not suitable due to the use of immunodeficient mice. With orthotopic congenic transplantation of tumor cells into mammary tissue, we gain more control and reproducibility regarding tumor growth, while retaining a functioning immune response. Here, we provide a protocol for isolating primary tumor cells from the MMTV-PyMT mouse model and their use in developing an orthotopic mouse model of breast cancer.

The Role of Cysteine Protease Cathepsins B, H, C, and X/Z in Neurodegenerative Diseases and Cancer

Papain-like cysteine proteases are composed of 11 human cysteine cathepsins, originally located in the lysosomes. They exhibit broad specificity and act as endopeptidases and/or exopeptidases. Among them, only cathepsins B, H, C, and X/Z exhibit exopeptidase activity. Recently, cysteine cathepsins have been found to be present outside the lysosomes and often participate in various pathological processes. Hence, they have been considered key signalling molecules. Their potentially hazardous proteolytic activities are tightly regulated. This review aims to discuss recent advances in understanding the structural aspects of these four cathepsins, mechanisms of their zymogen activation, regulation of their activities, and functional aspects of these enzymes in neurodegeneration and cancer. Neurodegenerative effects have been evaluated, particularly in Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and neuropsychiatric disorders. Cysteine cathepsins also participate in tumour progression and metastasis through the overexpression and secretion of proteases, which trigger extracellular matrix degradation. To our knowledge, this is the first review to provide an in-depth analysis regarding the roles of cysteine cathepsins B, H, C, and X in neurodegenerative diseases and cancer. Further advances in understanding the functions of cysteine cathepsins in these conditions will result in the development of novel, targeted therapeutic strategies.