To be able to establish the molecular mechanism of KRIBB3dependent growth inhibition, we analyzed Wnt Pathway cell cycle progression in a period dependent manner. Sixty percent of cells were arrested at the G2/M section 12 h after KRIBB3 treatment. Cell cycle arrest at the G2/M phase was further confirmed by finding the G2/M phase particular protein Cyclin B1 and phosphorylation of Histone H3. There are lots of possible KRIBB3 targets in charge of a KRIBB3dependent G2/M cycle arrest. Deposition of Cyclin B1 means that its deterioration route could be blocked by KRIBB3. Cyclin B1 is degraded by the proteasome in a cycle dependent fashion after APC/C dependent ubiquitination. Therefore,we decided to test whether KRIBB3 inhibits APC/ C dependent action. APC/C dependent ubiquitination is dependent on CDC20 to identify its substrate. That substrate recognition protein is associated with its inhibitory protein Mad2. Therefore, we examined the forming of the inhibitory complex p55CDC/ Mad2 in a period dependent manner after KRIBB3 treatment. Needlessly to say, KRIBB3 treatment induced association of p55CDC with the Icotinib inhibitory protein Mad2. This inhibitory complex may stop APC/C dependent Cyclin B1 wreckage. This contributes to the problem of how KRIBB3 triggers the complex of p55CDC/Mad2. Since microtubule toxins such as vinca alkaloids trigger all kinetochores to become indifferent, thus making a mitotic checkpoint indication, we made a decision to test whether KRIBB3 might prevent microtubule structure. We carried out indirect immunofluorescence microscopy to test the microtubule cytoskeleton in vivo. Cells treated with KRIBB3 showed small microtubule fragments Metastatic carcinoma in the cytoplasm. This design resembles microtubules in cells treated with nocodazole. Furthermore, in vitro, purified tubulin polymerization was inhibited in the presence of KRIBB3 or nocodazole, and increased in the presence of paclitaxel. Out of this, we figured KRIBB3 inhibited tubulin polymerization. The inhibitory activity of KRIBB3 on tubulin polymerization is comparable to that of nocodazole. But, KRIBB2, a lazy structural analogue of KRIBB3, didn’t show any inhibitory impact on tubulin polymerization. In keeping with this, KRIBB2 didn’t inhibit proliferation of HCT 116 cells. These results support our conclusion that inhibition of tubulin polymerization by KRIBB3 caused mitotic cycle arrest and growth inhibition. Since p53 has been proven to be involved in apoptosis and over 50 of human cancers have mutated p53, it is very important to drugs to be able to induce apoptosis in a p53independent manner. Therefore, we tested whether KRIBB3 can prevent the growth of p53 null cancer cell lines. Luckily, KRIBB3 was able to induce cell order Fingolimod cycle arrest at the mitotic phase, and apoptosis of equally HCT 116 and DU 145 cells.