Microtubules (Tubulin) (Tubulin)

Microtubules are essential components of the cytoskeleton, formed by the polymerization of alpha- and beta-tubulin heterodimers (UniProt P07437). They play a fundamental role in maintaining cell shape, enabling intracellular transport, and facilitating the segregation of chromosomes during mitosis (Nature Reviews Drug Discovery, 2021). Because rapid cell division is a hallmark of cancer, disrupting microtubule dynamics is a proven strategy for inhibiting tumor growth. Monomethyl auristatin E (MMAE) is a synthetic antimitotic agent that acts as a potent microtubule inhibitor by binding to tubulin and preventing its polymerization (PubChem CID 16218542). MMAE is too toxic for systemic administration as a standalone drug and is therefore utilized as a cytotoxic payload in antibody-drug conjugates (ADCs), often referred to as "vedotins" (FDA: Adcetris Prescribing Information). Once the ADC binds to a specific cell-surface antigen and is internalized, MMAE is released proteolytically to exert its cytotoxic effect. This targeted delivery results in G2/M phase cell cycle arrest and subsequent programmed cell death in the target malignant cells (Journal of Clinical Oncology, 2020). Clinical applications of MMAE-linked ADCs include the treatment of Hodgkin lymphoma, urothelial carcinoma, and certain types of breast and cervical cancers.

Other names

TubulinAlpha-tubulinBeta-tubulinMicrotubule filamentsMitotic spindle

MMAE binds to the vinca alkaloid binding site on tubulin, inhibiting its polymerization into microtubules. This disruption prevents the formation of a functional mitotic spindle, leading to cell cycle arrest at the G2/M phase and the induction of apoptosis (PubChem CID 16218542; Nature Reviews Drug Discovery, 2021).