The evolution of spindles and their mechanical implications for cancer metastasis.

The mitotic spindle has long been known to play a crucial role in mitosis, orchestrating the segregation of chromosomes into two daughter cells during mitosis with high fidelity. Intracellular forces generated by the mitotic spindle are increasingly well understood, and recent work has revealed that the efficiency and the accuracy of mitosis is ensured by the scaling of mitotic spindle size with cell size. However, the role of the spindle in cancer progression has largely been ignored. Two recent studies point toward the role of mitotic spindle evolution in cancer progression through extracellular force generation. Cancer cells with lengthened spindles exhibit highly increased metastatic potential. Further, interpolar spindle elongation drives protrusive extracellular force generation along the mitotic axis to allow mitotic elongation, a morphological change that is required for cell division. Together, these findings open a new research area studying the role of the mitotic spindle evolution in cancer metastasis.