1. Field of the Invention
The invention relates generally to anti-neoplastic agents, and more particularly to salinosporamides and their use as anti-neoplastic agents.
2. Background Information
Neoplastic diseases, characterized by the proliferation of cells not subject to the normal control of cell growth, are a major cause of death in humans. Clinical experience in chemotherapy has demonstrated that new and more effective cytotoxic drugs are desirable to treat these diseases. Indeed, the use of anti-neoplastic agents has increased due to the identification of new neoplasms and cancer cell types with metastases to different areas, and due to the effectiveness of antineoplastic treatment protocols as a primary and adjunctive medical treatment for cancer.
Since anti-neoplastic agents are cytotoxic (poisonous to cells) they not only interfere with the growth of tumor cells, but those of normal cells. Anti-neoplastic agents have more of an effect on tumor cells than normal cells because of their rapid growth. Thus, normal tissue cells that are affected by anti-neoplastic agents are rapidly dividing cells, such as bone marrow (seen in low blood counts), hair follicles (seen by way of hair loss) and the GI mucosal epithelium (accounting for nausea, vomiting, loss of appetite, diarrhea). In general, anti-neoplastic agents have the lowest therapeutic indices of any class of drugs used in humans and hence produce significant and potentially life-threatening toxicities. Certain commonly-used anti-neoplastic agents have unique and acute toxicities for specific tissues. For example, the vinca alkaloids possess significant toxicity for nervous tissues, while adriamycin has specific toxicity for heart tissue and bleomycin has for lung tissue.
Thus, there is a continuing need for anti-neoplastic agents that are effective in inhibiting the proliferation of hyperproliferative cells while also exhibiting IC50 values lower than those values found for current anti-neoplastic agents, thereby resulting in marked decrease in potentially serious side effects.