Cytochalasin J can alter mitotic spindle microtubule organization and kinetochore structure.

The cytochalasins are cell-permeable fungal metabolites inhibiting actin polymerization, which can alter diverse processes including cell movement, growth, phagocytosis, degranulation, and secretion.

In vitro: Cytochalasin J was identified as a deacetylated analog of cytochalasin H that weakly inhibited actin assembly but significantly altered mitotic spindle microtubule organization and kinetochore structure [1]. In a previous study, cytochalasin J treatment of prometaphase cells reduced the number of kMTs and the size and organization of the kinetochore lamina. Moreover, in approximately 30% of cells treated with cytochalasin J, the failure of a small number of chromosomes to attach to spindle fibers could be documented. These chromosomes showed a significant change in the organization of the kinetochore laminae. Light microscopic analyses of cells treated with cytochalasin J revealed loss of chromosome congression, with chromsomes usually located at the periphery of the spindle. Cells treated with 10 microg/ml cytochalasin J for 10 min and released into tissue culture medium showed a resumption of chromosome motion within a few minutes, both during congression and anaphase [2].

In vivo: Up to now, there is no animal in vivo data reported.

Clinical trial: So far, no clinical study has been conducted.

References:
[1] Walling, E. A.,Krafft, G.A. and Ware, B.R. Actin assembly activity of cytochalasins and cytochalasin analogs assayed using fluorescence photobleaching recovery. Archives of Biochemistry and Biophysics 264(1), 321-332 (1988).
[2] Wrench, G. A. and Snyder, J.A. Cytochalasin J treatment significantly alters mitotic spindle microtubule organization and kinetochore structure in PtK1 cells. Cell Motility and the Cytoskeleton 36(2), 112-124 (1997).