TRAIL Inactivates the Mitotic Checkpoint and Potentiates Death Induced by Microtubule-Targeting Agents in Human Cancer Cells

Abstract

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted interest as an anticancer treatment, when used in conjunction with standard chemotherapy. We investigated the mechanistic basis for combining low-dose TRAIL with microtubule-targeting agents that invoke the mitotic checkpoint. Treatment of T98G and HCT116 cells with nocodazole alone resulted in a robust mitotic block with initially little cell death; low levels of cell death were also seen with TRAIL alone at 10 ng/mL final concentration. In contrast, the addition of low-dose TRAIL to nocodazole was associated with maximally increased caspase-3, caspase-8, and caspase-9 activation, which efficiently abrogated the mitotic delay and markedly increased cell death. In contrast, the abrogation of mitotic checkpoint and increased cell death were blocked by inhibitors of caspase-8 and caspase-9 or pan-caspase inhibitor. The addition of TRAIL to either nocodazole or paclitaxel (Taxol) reduced levels of the mitotic checkpoint proteins BubR1 and Bub1. BubR1 mutated for the caspase cleavage sites, but not wild-type BubR1, was resistant to cleavage induced by TRAIL added to nocodazole, and partially blocked the checkpoint abrogation. These results suggest that adding a relatively low concentration of TRAIL to antimicrotubule agents markedly increases complete caspase activation. This in turn accentuates degradation of spindle checkpoint proteins such as BubR1 and Bub1, contributes to abrogation of the mitotic checkpoint, and induces cancer cell death. These results suggest that TRAIL may increase the anticancer efficacy of microtubule-targeting drugs. [Cancer Res 2008;68(9):3440-9]

Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) and paclitaxel have cooperative in vivo effects against glioblastoma multiforme cells

“…2D, top, bottom set of wells) as assessed with bioluminescence. These observations together are consistent with our previous observation that TRAIL markedly sensitizes cancer cells to paclitaxel (9), but intriguingly also suggest that the effects of paclitaxel and TRAIL in GBM cells may be attenuated when wild-type p53 protein is expressed.…”

“…We present here the first preliminary report on the in vivo efficacy of TRAIL plus paclitaxel against human GBM xenografts using multimodality imaging including bioluminescence, microscale computed tomography (microCT), and positron emission tomography (PET). This work therefore confirms, in an in vivo GBM model system, our previously reported in vitro findings that combined TRAIL and paclitaxel treatment leads to maximal anticancer efficacy (9).…”

“…We have proposed that TRAIL may increase the efficacy of chemotherapy invoking the mitotic checkpoint by augmenting caspase activation, which facilitates the degradation of spindle checkpoint proteins such as BubR1 and Bub1, resulting in abrogation of the cell cycle checkpoint (9). It has been suggested that activation of p53-dependent checkpoints may prevent cell death caused by microtubule-active drugs (16).…”

“…We previously showed that abrogation of the antimicrotubule-induced mitotic checkpoint by TRAIL leads to increased cancer cell death (9). We therefore sought to test whether the induced expression of wild-type p53 could potentially protect cells from the lethal effects of TRAIL on mitosis.…”

“…We recently reported our findings on the in vitro anticancer efficacy of TRAIL when combined with the microtubule-targeting drugs nocodazole and paclitaxel (9). Combined treatment led to markedly greater caspase activation, and abrogation of the mitotic checkpoint than either TRAIL or microtubuletargeting alone, and caused significantly greater cancer cell death.…”