I think it doesn't promote cell division directly. IIUC this make the cell during the division to not wait until the chromosomes are correctly split, so the new cell have a high chance of getting a wrong number of chromosome and die. Since the cell doesn't wait until everything is in order, the division is faster.

Form the abstract: https://mct.aacrjournals.org/content/18/10/1696

> In in vivo pharmacodynamic experiments, BOS172722 potently inhibits the spindle assembly checkpoint induced by paclitaxel in human tumor xenograft models of TNBC, [....]

I think the key part is "spindle assembly checkpoint" https://en.wikipedia.org/wiki/Spindle_checkpoint

Oh interesting. It's basically working in a similar way to Colchicine then. Colchicine blows up the microtubules so the chromosomes don't segregate properly. The combination of the two might be effective, though I suspect there's a toxicity issue or something else I'm missing.