There is an obvious urgent need to find effective and safe therapies to prevent both recurrence and progression of bladder cancer. In the present study, we report that fisetin-induced apoptosis in human bladder cancer is mediated via modulation of two related pathways: up-regulation of p53 and down-regulation of NF-kappa B activity, causing a change in the ratio of pro-and anti-apoptotic proteins. The results showed that fisetin inhibited the proliferation of T24 and EJ cells by inducing apoptosis and blocking cell cycle progression in the G0 ⁄ G1 phase. Western blot assay showed that fisetin significantly increases the expression of p53 and p21 proteins, and decreases the levels of cyclin D1, cyclin A, CDK4 and CDK2, thereby contributing to cell cycle arrest. In addition, fisetin increased the expression of Bax and Bak but decreased the levels of Bcl-2 and Bcl-xL and subsequently triggered mitochondrial apoptotic pathway. Our study suggests that the activation of p53 and inhibition of the NF-kappa B system may play important roles in the fisetin-induced apoptosis in bladder cancer cells.
BTK is a member of the TEC family
of non-receptor tyrosine kinases
whose deregulation has been implicated in a variety of B-cell-related
diseases. We have used structure-based drug design in conjunction
with kinome profiling and cellular assays to develop a potent, selective,
and irreversible BTK kinase inhibitor, QL47, which covalently modifies
Cys481. QL47 inhibits BTK kinase activity with an IC50 of
7 nM, inhibits autophosphorylation of BTK on Tyr223 in cells with
an EC50 of 475 nM, and inhibits phosphorylation of a downstream
effector PLCγ2 (Tyr759) with an EC50 of 318 nM. In
Ramos cells QL47 induces a G1 cell cycle arrest that is associated
with pronounced degradation of BTK protein. QL47 inhibits the proliferation
of B-cell lymphoma cancer cell lines at submicromolar concentrations.
Quercetin, a flavonoid found in many fruits and vegetables, belongs to an extensive class of polyphenolic compounds. Previous studies reported that quercetin inhibits the proliferation of various cancer cells and tumor growth in animal models. We investigated the growth inhibition and colony formation of quercetin on three bladder cancer cells (EJ, J82 and T24). The expression of tumor suppressor genes and oncogenes such as P53, Survivin, PTEN, as well as the methylation status of these genes was also evaluated. We observed that quercetin induced apoptosis in bladder cancer cells in a time- and dose-dependent manner. Quercetin (100 micromolars) significantly inhibited EJ, T24 and J82 cell growth accompanied by an increase in the G0/G1 phase. In all cell lines, quercetin decreased the expression of mutant P53 and Survivin proteins. However, there was no change in the level of PTEN protein. Moreover, the DNA methylation levels of the estrogen receptor (Er-beta), P16INK4a and RASSF1A were strongly decreased (from 35 to 70%) in the quercetin-treated group compared to the control. In conclusion, our study suggested that quercetin inhibits growth, colony formation and hypermethylation of bladder cancer cell lines. Quercetin-induced apoptosis might be associated with a decrease in mutant P53 and Survivin proteins.
Objectives:To investigate the inhibitory effect of sodium butyrate (NaB) on the proliferation of human bladder cancer cell lines and its synergetic effect with anticancer drugs in treating bladder cancer in vitro and in vivo. Methods: The inhibitory effects of NaB on human bladder cancer cell lines in vitro and the synergetic effect of NaB with mitomycin c, cisplatin (CDDP) and adriamycin were detected by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Hoechst staining and electron microscopy were used to observe morphology for apoptotic cells after NaB treatment. Fas, bcl-2 and caspase-3 were determined with flow cytometry. In vivo synergetic effects were detected in N-methyl-N-nitrosourea induced bladder cancer model rats. Results: NaB significantly inhibited the growth of bladder cancer cell lines in a concentration and time dependent manner. Better results of tumor inhibition have been achieved when NaB was combined with CDDP, mitomycin c and adriamycin, rather than used alone. Furthermore, 2 h exposure to NaB can sensitize bladder cancer to chemotherapy agents. The Bcl-2 expression in bladder cancer cells is decreased and caspase-3 expression increased after NaB treatment. Intravesical application of NaB combined with CDDP can significantly inhibit tumor growth and progression. Conclusions: NaB has a direct anticancer effect and can markedly enhance the action of several chemotherapy agents. 2 h expose to NaB can also sensitize bladder cancer to anticancer drugs. NaB may be an excellent candidate agent for intravesical application in treating bladder cancer.
BTK kinase is a member of the TEC kinase family and is a key regulator of the B-cell Receptor (BCR)-mediated signaling pathway. It is important for B-cell maturation, proliferation, survival and metastasis. Pharmacological inhibition of BTK is clinically effective against a variety of B-cell malignances, such as MCL, CLL and AML. MNK kinase is one of the key downstream regulators in the RAF-MEK-ERK signaling pathway and controls protein synthesis via regulating the activity of eIF4E. Inhibition of MNK activity has shown moderate efficacy for AML cell lines proliferation. Through a structure-based drug design approach, we have discovered a selective and potent BTK/MNK dual kinase inhibitor (QL-X-138), which exhibits covalent binding to BTK and non-covalent binding to MNK. Compared to the BTK kinase inhibitor (PCI-32765) and the MNK kinase inhibitor (cercosporamide), QL-X-138 displays a stronger anti-proliferative effect against a variety of B-cell cancer cell lines, as well as AML and CLL primary patient cells. The agent can effectively arrest the growth of lymphoma and leukemia cells at the G0–G1 stage and can induce strong apoptotic cell death. These results demonstrated that simultaneous inhibition of BTK and MNK kinase activity might be a new therapeutic strategy for B-cell malignances.
We have previously reported that curcumin inhibits urothelial tumor development in a rat bladder carcinogenesis model. In this study, we report that curcumin inhibits urothelial tumor development by suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway. Curcumin inhibits IGF2 expression at the transcriptional level and decreases the phosphorylation levels of IGF1R and IRS-1 in bladder cancer cells and N-methyl-N-nitrosourea (MNU)-induced urothelial tumor tissue. Ectopic expression of IGF2 and IGF1R, but not IGF1, in bladder cancer cells restored this process, suggesting that IGF2 is a target of curcumin. Moreover, introduction of constitutively active AKT1 abolished the inhibitory effect of curcumin on cell proliferation, migration, and restored the phosphorylation levels of 4E-BP1 and S6K1, suggesting that curcumin functions via suppressing IGF2-mediated AKT/mTOR signaling pathway. In summary, our results reveal that suppressing IGF2 and IGF2-mediated PI3K/AKT/mTOR signaling pathway is one of the mechanisms of action of curcumin. Our findings suggest a new therapeutic strategy against human bladder cancer caused by aberrant activation of IGF2, which are useful for translational application of curcumin.
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