Dolastatin 15 is a member of the dolastatin family. Dolastatins are marine natural products isolated from the sea hare|Dolabella auricularia|with a structure related to Dolastin 10. Dolastatin 15 is an anti-neoplastic pseudopeptide that inhibits Tubulin-dependent GTP hydrolysis to Tubulin but has been shown to bind to the RZX/MAY region. The compound acts as a weak Tubulin inhibitor by binding to the vinca domain of tubulin and induces apoptosis through Bcl-2 phosphorylation in several malignant cell types. Potent inhibitor of the proliferation of murine and cancer cell lines as well as that of hematopoietic progenitor cells. When added to leukemia cultures Dolastin 15 inhibited both immunoglobulin production and cell proliferation.