Time schedule-dependent effect of the CK2 inhibitor TBB on PC-3 human prostate cancer cell viability.

Inhibitors of CK2 kinase inhibit cell proliferation and induce apoptosis in numerous cancer cell lines. Due to these properties, they are considered potentially useful in anticancer therapy. In this study, we show that the exact effect of the specific CK2 inhibitor TBB on PC-3 human prostate cancer cell viability depends on the time schedule of administration: it was not observed when the treatment was directly followed by the viability assay but it appeared when the treatment and the assay were separated by a 24-h incubation without the inhibitor. Such a pattern was maintained when the TBB treatment was combined with either camptothecin or TRAIL. The time schedule-dependence of cell viability was not reflected by a similar dependence of induction of apoptosis. Despite this, the schedule in which a treatment with the CK2 inhibitor precedes that with an anticancer drug seems to be a good choice for a potential therapy against androgen-refractory prostate cancer.