BioProject

Bone is the primary site of breast cancer metastasis and complications associated with bone metastases can lead to a significantly decreased quality of life in these patients. More...

Bone is the primary site of breast cancer metastasis and complications associated with bone metastases can lead to a significantly decreased quality of life in these patients. Thus, it is essential to gain a better understanding of the molecular mechanisms that underlie the emergence and growth of breast cancer skeletal metastases. Methods: To search for novel molecular mediators that influence breast cancer bone metastasis, we generated gene expression profiles from laser capture micro-dissected trephine biopsies of both breast cancer bone metastases and primary breast tumors that metastasized to bone. Bioinformatics analysis identified genes that are differentially expressed in breast cancer bone metastases compared to primary mammary tumors. Results: ABCC5, an ATP-dependent transporter, was found to be overexpressed in breast cancer osseous metastases relative to primary mammary tumors. In addition, ABCC5 was significantly up-regulated in human and mouse breast cancer cell lines with high bone-metastatic potential. Stable knockdown of ABCC5 significant reduced bone metastatic burden and osteolytic bone destruction in mice. The decrease in osteolysis was further associated with diminished osteoclast numbers. Conclusions: Our data, for the first time, suggests that ABCC5 functions as a mediator of breast cancer skeletal metastasis. ABCC5 expression in breast cancer cells is important for the efficient bone resorption mediated by osteoclasts. Hence, ABCC5 may be a potential therapeutic target for breast cancer bone metastasis. Overall design: primary breast tumors vs. bone trephine biopsies Less...