Using breast cancer cell CXCR4 surface expression to predict liposome binding and cytotoxicity.

The primary cause of mortality in breast cancer is tumor aggressiveness, characterized by metastases to regional lymph nodes, bone marrow, lung, and liver. C-X-C chemokine receptor type 4 (CXCR4) has been shown to mobilize breast cancer cells along chemokine gradients. Quantification of CXCR4 surface expression may predict the efficacy of anti-CXCR4 labeled liposomal therapeutics to target and kill breast cancer cells. We evaluated gene and surface receptor expression of CXCR4 on breast cancer cell lines distinguished as having low and high invasiveness, MDA-MB-175VII and HCC1500, respectively. CXCR4 surface expression did not correlate with invasiveness. MDA-MB-175VII exhibited more binding to anti-CXCR4 labeled liposomes relative to HCC1500. Increased binding correlated with greater cell death relative to IgG labeled liposomes. Quantitative cell characterization may be used to select targeted therapeutics with enhanced efficacy and minimal side effects.