1,1-Bis(3V -indolyl)-1-(p-substitutedphenyl)methanes containing p-trifluoromethyl (DIM-C-pPhCF 3 ), p-t-butyl (DIM-CpPhtBu), and phenyl (DIM-C-pPhC 6 H 5 ) substituents have been identified as a new class of peroxisome proliferator-activated receptor ; (PPAR;) agonists that exhibit antitumorigenic activity. The PPAR;-active C-DIMs have not previously been studied against bladder cancer. We investigated the effects of the PPAR;-active C-DIMs on bladder cancer cells in vitro and bladder tumors in vivo. In this study, the PPAR;-active compounds inhibited the proliferation of KU7 and 253J-BV bladder cancer cells, and the corresponding IC 50 values were 5 to 10 and 1 to 5 Mmol/L, respectively. In the less responsive KU7 cells, the PPAR; agonists induced caveolin-1 and p21 expression but no changes in cyclin D1 or p27; in 253J-BV cells, the PPAR; agonists did not affect caveolin-1, cyclin D1, or p27 expression but induced p21 protein. In KU7 cells, induction of caveolin-1 by each of the PPAR; agonists was significantly down-regulated after cotreatment with the PPAR; antagonist GW9662. DIM-C-pPhCF 3 (60 mg/kg thrice a week for 4 weeks) inhibited the growth of implanted KU7 orthotopic and s.c. tumors by 32% and 60%, respectively, and produced a corresponding decrease in proliferation index. Treatment of KU7 cells with DIM-C-pPhCF 3 also elevated caveolin-1 expression by 25% to 30%, suggesting a role for this protein in mediating the antitumorigenic activity of DIM-C-pPhCF 3 in bladder cancer. (Cancer Res 2006; 66(1): 412-8)

Objective: Docetaxel causes cell death through induction of apoptosis; however, cell death characteristics for docetaxel have not yet been fully elucidated.We examined the role of focal adhesion kinase (FAK) cleavage in docetaxel-mediated apoptosis. Methods: FAK degradation after treatment with docetaxel was determined in both taxanesensitive (HeyA8 and SKOV3) and taxane-resistant (HeyA8-MDR and SKOV3-TR) ovarian cancer cell lines byWestern blot analysis. Cell growth was determined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. FAK-targeting small interfering RNA (siRNA) was used to decrease FAK expression. Apoptosis and caspase activity were determined using commercially available kits. Results: SKOV3 and HeyA8 cell lines were both sensitive to docetaxel (IC 50 levels,1-6.2 nmol/L), whereas the SKOV3-TR and HeyA8-MDR cells were resistant (IC 50 z 250 nmol/L for both). Docetaxel induced high rates of apoptosis in SKOV3 and HeyA8 cells (84% and 66% apoptosis, respectively) but minimal apoptosis (5-8%) in SKOV3-TR and HeyA8-MDR cells. Similarly, FAK was cleaved in SKOV3 and HeyA8 cells in response to docetaxel treatment but unchanged in the resistant cells. Caspase-3 and caspase-8 activity also increased significantly in docetaxel-treated SKOV3 and HeyA8 cells but not in the taxane-resistant cells. DEVD-fmk (caspase-3 blocker) was able to block both FAK cleavage and apoptosis mediated by docetaxel in SKOV3 and HeyA8 cells. FAK siRNA transfection resulted in 70% to 90% decrease in FAK levels in all cell lines within 72 hours. FAK silencing augmented docetaxel-mediated growth inhibition (5-to 8-fold increase) and apoptosis in both of the taxane-sensitive and taxane-resistant cell lines. Conclusions: Docetaxel induces FAK cleavage, mediated through activation of caspase-3, in taxane-sensitive ovarian cancer cells but not in taxane-resistant cells. The absence of FAK degradation may contribute to cell survival in taxane-resistant cells. FAK silencing promotes the in vitro efficacy of docetaxel in both taxane-sensitive and taxane-resistant cell lines and may serve as a novel therapeutic approach.

hTid-1, a human homolog of the Drosophila tumor suppressor l(2)Tid and a novel DnaJ protein, regulates the activity of nuclear factor B (NF-B), but its mechanism is not established. We report here that hTid-1 strongly associated with the cytoplasmic protein complex of NF-B-IB through direct interaction with IB␣/␤ and the IKK␣/␤ subunits of the IB kinase complex. These interactions resulted in suppression of the IKK activity in a J-domain-dependent fashion and led to the cytoplasmic retention and enhanced stability of IB. Overexpression of hTid-1 by using recombinant baculovirus or adenovirus led to inhibition of cell proliferation and induction of apoptosis of human osteosarcoma cells regardless of the p53 expression status. hTid-1 is a human homologue of the Drosophila tumor suppressor Tid56 encoded by the lethal(2)tumorous imaginal discs, or l(2)tid, gene (26). Loss of the l(2)tid gene causes malignancy of the anlagen of the adult organs, the imaginal discs in Drosophila (26). hTid-1 was initially identified as a cellular target for the viral oncogenic protein E7 derived from human papillomavirus type 16 (HPV16) (36). hTid-1 also serves as the intracellular target for the viral transforming protein Tax from human T-cell leukemia virus type 1 (HTLV-1) and represses the Tax-induced transactivation of nuclear factor B (NF-B) (7,8). Subsequent studies demonstrated that hTid-1 interacts with the viral nuclear protein UL9 from herpes simplex virus type 1 (HSV-1) in enhancing the binding of UL9 to the viral genome to facilitate viral replication (14) and that hTid-1 forms a protein complex with Jak2 tyrosine kinase, adversely affecting its kinase activity (35).The htid1 gene encodes two spliced variants of hTid-1, hTid-1 L , and hTid-1 S (37). The full-length hTid-1 L (long) comprises 480 amino acids, whereas hTid-1 S (short), generated via alternative splicing, produces a predicted protein of 453 amino acids that lacks the C-terminal 33 amino acids of hTid-1 L but contains an additional 6 amino acids (KRSTGN) (37). Aside from differences at the C termini, both hTid-1 variants share identical structural motifs, including an N-terminal mitochondria-processing signal peptide, an N-terminal conserved signature J domain, and a central cysteine-rich motif. hTid-1 was classified as a member of the DnaJ protein family and a molecular cochaperone based on its signature J domain and ability to interact with the heat shock protein 70 chaperone (Hsp70) (25,27). Currently, the biological functions of these two forms of hTid-1 are unclear. The two variants were reported to exhibit opposing effects on induction of apoptosis in the human osteosarcoma cell line U2OS in response to tumor necrosis factor-alpha (TNF-␣) and mitomycin C (37), but the mechanism by which hTid-1-mediated apoptosis and antiapoptosis is unknown. Whether hTid-1 functions as a human tumor suppressor is also unknown. The early reports that hTid-1 serves as an intracellular target for viral oncogenic proteins Tax and E7 suggest a role for hTid-1 as a tumor suppre...

No abstract

Vitamins C and K3 have significant antiproliferative and apoptotic effects when used in combination. This combination enhances the efficacy of gemcitabine against bladder cancer in vivo.