Structure-based discovery of a novel inhibitor targeting the ß-catenin/Tcf4 interaction.

Overactivation or overexpression of ß-catenin in the Wnt (wingless) signaling pathway plays an important role in tumorigenesis. Interaction of ß-catenin with T-cell factor (Tcf) DNA binding proteins is a key step in the activation of the proliferative genes in response to upstream signals of this Wnt/ß-catenin pathway. Recently, we identified a new small molecule inhibitor, named BC21 (C(32)H(36)Cl(2)Cu(2)N(2)O(2)), which effectively inhibits the binding of ß-catenin with Tcf4-derived peptide and suppresses ß-catenin/Tcf4 driven reporter gene activity. This inhibitor decreases the viability of ß-catenin overexpressing HCT116 colon cancer cells that harbor the ß-catenin mutation, and more significantly, it inhibits the clonogenic activity of these cells. Down-regulation of c-Myc and cyclin D1 expression, the two important effectors of the Wnt/ß-catenin signaling, is confirmed by treating HCT116 cells with BC21. This compound represents a new and modifiable potential anticancer candidate that targets ß-catenin/Tcf-4 interaction.

Development of a novel fluorescence polarization-based assay for studying the ß-catenin/Tcf4 interaction.

Aberrant activation of the Wnt/ß-catenin signaling pathway is associated with a wide range of human cancers. The interaction of ß-catenin with T cell factor (Tcf) is a key step in activation of proliferative genes in this pathway. Interruption of this interaction would be a valuable strategy as a tumor therapy. In this study, we developed a novel fluorescein isothiocyanate (FITC)-labeled Tcf4-derived probe for identification of inhibitors of the ß-catenin/Tcf4 interaction using a fluorescence polarization assay. This assay shows high potential for use in high-throughput screening for the discovery of inhibitors of the ß-catenin/Tcf4 interaction.

Combination chemotherapy with 5-fluorouracil, methotrexate and etoposide for patients with high-risk gestational trophoblastic tumors: a report based on our 11-year clinical experiences.

OBJECTIVES: To evaluate the efficacy, toxicity, and survival of patients with high-risk gestational trophoblastic tumors (GTTs) treated with the 5-fluorouracil (5-FU), methotrexate (MTX) and etoposide (VP-16) regimen. METHODS: Between 1992 and 2003, 26 consecutive patients with FIGO-defined high-risk GTTs were treated with 5-FU, MTX and VP-16 regimen. Among them, 9 patients had received prior chemotherapy. Remission rate, causes of treatment failure, and toxicity were analyzed retrospectively. RESULTS: After treatment with 5-FU, MTX and VP-16 regimen, 21 of 26 gained complete respond (80.8%). Two patients were performed adjuvant hysterectomy and both cured ultimately. Five developed resistance (19.2%), and 1 died of widespread metastases (3.8%). All 5 patients who developed resistance were treated with multidrug regimen of etoposide, methotrexate, and actionmycin D alternating with cyclophosphamide and vincristine (the EMA/CO); 4 were salvaged and 1 died of refractory disease. No ones relapsed. WHO grade 4 leukocytopenia and thrombocytopenia with the 5-FU, MTX and VP-16 regimen occurred in 9.0% and 2.4%, respectively, of the total 167 cycles; other toxic effects were acceptable and manageable. With mean follow up of 37 months, neither relapse nor secondary tumor was observed. CONCLUSIONS: According to our 11 years of clinical observation, 5-FU, MTX and VP-16 chemotherapy is one of effective multiagent regimen for patients with high-risk GTTs. Its toxicity is mild and manageable. For patients with high-risk and refractory GTTs, this new triple salvage chemotherapy regimen may be an effective alternative.