Overcoming limitations of natural anticancer drugs by combining with artificial agents.

During a billion years of evolution, living creatures have perfected cytotoxic agents to kill other organisms without killing themselves, thus providing us with antibiotics to kill bacteria without killing eukaryotic (e.g. human) cells. Some natural agents inhibit specifically most vital cellular structures and functions in cancer cells. However, nature was not creating antibiotics for cancer, and natural agents kill cancer cells precisely because they share targets with normal cells. To discriminate between particular cancer cells and normal cells, we can design or select artificial agents that are not necessarily lethal but are aimed either at cancer-specific targets or at dispensable and even unavailable (in cancer cells) targets. Using rational drug combinations, such selective agents can assist natural agents to eradicate cancer cells selectively.