There is evidence to support several hypotheses of the target site and mechanism of action of genistein. Some of these are inhibition of angiogenesis, interaction with steroid hormone receptors, inhibition of tyrosine kinase, inhibition of radical oxygen species formation, and interaction with topoisomerase, one of the more important mechanism in regulating cellular proliferation. Several anticancer agents create their effects by interrupting cell division. Since cancer cells are dividing at a more rapid rate than the normal cells around them, the chemotherapeutic agents have a proportionally greater impact on the tumor cells. The target site for the taxoids and the well-known Vinca alkaloids is microtubule formation.
Microtubules are critical to spindle and aster formation in all cells as they prepare for mitosis.
Microtubules also have other cellular functions, such as maintenance of cell shape, cellular motility and attachment, and intracellular transport. Tubulin dimers polymerize to form microtubules. They have been used for many years in treating lymphomas and acute childhood leukemia, respectively. Vincristine and vinblastine inhibit cancer cell reproduction by promoting microtubule disassembly. They bind to the tubulin dimers.