Immunofluorescence study of the action of navelbine, vincristine and vinblastine on mitotic and axonal microtubules

Abstract

Among the various non-naturally-occurring Vinca alkaloid compounds, nor-anhydro-vinblastine (Navelbine, NVB) exhibits in preliminary clinical studies broader anti-tumor activity and lower neurotoxicity than vinblastine (VBL) and vincristine (VCR). The action of these 3 Vinca alkaloids on axonal and mitotic microtubules has been studied experimentally in a specific model, the tectal plate anlage of mouse embryos at the earliest stages of neuronal differentiation. Post-implantation embryos were cultured in toto in a medium containing increasing concentrations of drugs. Microtubules were stained using immunofluorescence with a tubulin-specific polyclonal antibody in semi-thin sections after embedding in high-molecular-weight polyethylene glycol. All drugs induced depolymerization of mitotic interpolar microtubules and cell metaphase block at the same concentration. Increasing the concentrations led to progressive depolymerization of kinetochore microtubules. However, NVB was the only drug to induce complete microtubule depolymerization. The activity of the 3 compounds on axonal microtubules was identical: depolymerization of a labile pool of microtubules. This was observed at higher concentrations with NVB than with the 2 other Vinca alkaloids. Our results show that, in this model, NVB is as active on mitotic microtubules as VCR and VBL, and less active on axonal microtubules. None of the 3 drugs modified microtubule length but all appeared to induce disruption of the labile microtubule pool without altering the stable pool.

Co-delivery nanoparticles with characteristics of intracellular precision release drugs for overcoming multidrug resistance

“…Because VCR as a microtubule-destabilizing agent has the ability to advance the microtubule disassembly to arrest the cells in the metaphase phase of cell cycle, 18,48 we ascertained the efficacy on the subcellular level with CLSM method and flow cytometer (Figure 4). We visualized, respectively, the structural modification of the microtubule and the microfilament in A549 cell and A549/taxol cell induced by TPGS-PLGA NPs, free VCR, and TPGS-PLGA-VCR NPs applying tubulin-tracker red and actin-tracker green as fluorescence probes (Figure 4A-D).…”

“…48 Moreover, while some anticancer drugs belonging to the P-gp substrates, such as DOX, 46 were loaded into Co-NDDS; increasing intracellular concentration of the drugs became a pivotal challenge. Conventional countermeasures are increasing uptake and decreasing P-gp-related efflux.…”

Effective treatment of advanced breast cancer with vinorelbine, mitomycin C plus human granulocyte colony-stimulating factor

“…The target, however, remains cytosolic tubulin, a ubiquitous eukaryotic protein. Vinorelbine seems to disorganise microtubules of the mitotic figure at a lower concentration than other vinca alkaloids and one at which it fails to affect the axonal microtubules (Binet et al, 1990). These observations led to the suggestion that vinorelbine might be less neurotoxic and more toxic to the cancer cell.…”

True

“…Assessment of the minimum concentration of drug required to inhibit polymerization of the spindle, compared with damage to the axonal microtubule, shows a ratio of 20:1 (Meninger et al, 1989). An additional advantage over other vincaalkaloids lies in the selective production of mitotic tubulin paracrystallization which may point to enhanced cytotoxic action (Binet et al, 1990).…”