CalTech team combines two breast cancer drugs using nanoparticles
The drugs, trastuzumab (Genentech's Herceptin) and camptothecin, both act alone as cancer drugs, but they also have factors that limit their potential. Tumors tend to form a resistance to trastuzumab over time, and camptothecin's toxicity and low solubility hinder its usefulness, according to a report from the National Cancer Institute. But combined and delivered with a specific nanoparticle and antibody, the drugs form a more powerful cancer-fighting weapon.
Mark Davis and his CalTech team used a single antibody molecule bound to a camptothecin-laden nanoparticle as a targeting device--the antibody roots out the HER2 growth factor present in certain types of aggressive breast cancer. They then added a single molecule of trastuzumab to each nanoparticle.
In animal tests, breast tumor cells that overexpressed the HER2 protein took up the nanoparticle and obliterated tumors 9 days after a single injection. The animals remained tumor-free after 6 weeks, according to the NCI report. Animals receiving one or the other treatment, however, did not fare as well; tumors remained in some form and the animals did not survive.
The research, supported by the NCI Alliance for Nanotechnology in Cancer and published in the journal Molecular Pharmaceutics, took place at CalTech's Center of Cancer Nanotechnology Excellence.