Thiocolchicine is a colchicine-derivative used in the therapy of some diseases and extensively studied in the field of oncological research as antimitotic agent. It is tubulin polymerization and microtubule assembly inhibitor and axonal cytoskeleton modulator; apoptosis inducer. Thiocolchicine-dimers were shown to be potent topoisomerase I inhibitors. Thiocolchicine is a potential antitumor agent.

Ansamitocin P3, a structural analogue of maytansine, was isolated from Nocardia. Structurally maytansine and ansamitocin P3 are polyketide macrolactams differing in the acyl groups at the C3 position. Ansamitocin P-3 inhibited the polymerization of tubulin and depolymerized the once polymerized tubulin. Ansamitocin P3 exerts antitumour properties.

SB-743921 is a synthetic small molecule with potential antineoplastic properties. SB-743921 selectively inhibits the ATP-binding domain of the kinesin spindle protein (KSP), an important protein involved in the early stages of mitosis that is expressed in proliferating cells. Inhibition of KSP results in inhibition of mitotic spindle assembly and interrupts cell division, thereby causing cell cycle arrest and induction of apoptosis. SB-743921 has greater than 40,000 fold selectivity for KSP over other kinesins. SB-743921 has demonstrated promising anti-cancer activity in a variety of in vivo and in vitro human cancer models in preclinical studies. Furthermore, anti-cancer effect has been demonstrated in taxane-refractory malignancies with SB-743921. Toxicity studies demonstrated predictable neutropenias and gastrointestinal toxicities without clear evidence of neurotoxicity. The recommended phase II dose for SB-743921 as a 1-h infusion every 21 days is 4 mg/m2.

Baccatin III is an isolate of the Pacific yew tree (Taxus brevifolia) and related species. Baccatin III is the precursor to paclitaxel/ taxol. Antileukaemic and antitumor agent, Baccatin III, binds to tubules when they are assembled in the cell and stabilizes the polymerized form of tubules so that they remain assembled even under conditions in which microtubules dissociate into tubulin subunits. Baccatin III is also an inducer of apoptosis and shows antitumor properties in vitro. Baccatin III exerts anti-tumor immunomodulatory activity in very low doses (0.05-0.5mg/kg), although it is regarded as an inactive derivative of paclitaxel. Oral administration of Baccatin III significantly reduced the growth of tumors induced by engrafting BALB/c mice with either 4 T1 mammary carcinoma or CT26 colon cancer cells. Baccatin III reduced tumor progression by inhibiting the accumulation and suppressive function of MDSCs. Baccatin III inhibited cell proliferation of a number of cancer cell lines. The cytotoxic activity exhibited by fungal taxol and Baccatin III involves the same mechanism, dependent on caspase-10 and membrane potential loss of mitochondria, with taxol having far greater cytotoxic potential.

10-deactyltaxol (10-deacetylpaclitaxel) is a naturally occurring taxane related to taxol (paclitaxel). Taxol is an antitumor drug with cytotoxic properties that correlate with its microtubule-stabilizing activities. When compared to paclitaxel 10-deacetyltaxol is 100% as active as paclitaxel in promoting in vitro microtubule assembly, but is only 30% as cytotoxic as paclitaxel. 10-deactyltaxol is a semi-synthetic precursor of paclitaxel and considered to be paclitaxel impurity. 10-deactyltaxol, isolated from the bark of Taxus brevifolia, was converted into paclitaxel in one composite step (trimethylsilylation, acetylation, and desilylation) and in an overall yield of 80-85%.

Trimethylcolchicinic acid (also known as deacetyl colchicine) was used for patients with advanced malignancies. However, these studies were discontinued. Expeiments on rat were shown, that trimethylcolchicinic acid was able to improve normal liver histology, ultrastructure, collagen content and biochemical markers of liver damage in spite of that trimethylcolchicinic acid, didn't bind tubulin.

Estramustine is an antineoplastic agent indicated in the palliative treatment of patients with metastatic and/or progressive carcinoma of the prostate. Estramustine is a combination of estradiol with nitrogen mustard. In vivo, the nitrogen-mustard moiety becomes active and participates in alkylation of DNA or other cellular components. This causes DNA damage in rapidly dividing cancerous cells leading to cell death and ideally, tumor shrinkage. Also, due to the drugs estrogen component, it can bind more selectively to active estrogen receptors. Used for the palliative treatment of patients with metastatic and/or progressive carcinoma of the prostate.