Fig. 6

Proposed molecular mechanistic action of MBIC in HeLa cancer cell. a MBIC causes microtubule-kinetochore attachment error by interrupting microtubules polymerization. b Unattached kinetochores activate spindle assembly checkpoint (SAC). When SAC is activated, inhibits APC/C. BubR1 is a SAC member which inhibits metaphase to anaphase transition until all kinetochores are attached to microtubules correctly. Up-regulation of BubR1 is a sign of attachment error. c Cyclin B1 degradation is compulsory for exiting from mitosis. APC/C is responsible for Cyclin B1 degradation. Up-regulation of Cyclin B1 in our study shows that APC/C is not activated. d Down-regulation of Aurora B, one on chromosomal passenger complex (CPC) impairs SAC activity. e Down-regulation of Bcl-2 and up-regulation of Bax are signs of release of cytochrome c in cytosol and formation of apoptosome which activated caspase-9. Up-regulation of cleaved caspase-3/7/9 is a sign of mitochondrial-dependent apoptosis. f Up-regulation of cleaved PARP is a sign of DNA damage