Combined Inhibition of NEDD8-Activating Enzyme and mTOR Suppresses Loss-Driven Tumorigenesis.

Inactivation of /Merlin causes the autosomal-dominant cancer predisposition syndrome familial neurofibromatosis type 2 (NF2) and contributes to the development of malignant pleural mesothelioma (MPM). To develop a targeted therapy for -mutant tumors, we have exploited the recent realization that Merlin loss drives tumorigenesis by activating the E3 ubiquitin ligase CRL4, thereby inhibiting the Hippo pathway component Lats. Here, we show that MLN4924, a NEDD8-activating enzyme (NAE) inhibitor, suppresses CRL4 and attenuates activation of YAP in -mutant tumor cells.

Affinity-based proteomics reveal cancer-specific networks coordinated by Hsp90.

Most cancers are characterized by multiple molecular alterations, but identification of the key proteins involved in these signaling pathways is currently beyond reach. We show that the inhibitor PU-H71 preferentially targets tumor-enriched Hsp90 complexes and affinity captures Hsp90-dependent oncogenic client proteins. We have used PU-H71 affinity capture to design a proteomic approach that, when combined with bioinformatic pathway analysis, identifies dysregulated signaling networks and key oncoproteins in chronic myeloid leukemia.

Design, synthesis, and evaluation of small molecule Hsp90 probes.

A number of compounds from different chemical classes are known to bind competitively to the ATP-pocket of Hsp90 and inhibit its chaperone function. The natural product geldanamycin was the first reported inhibitor of Hsp90 and since then synthetic inhibitors from purine, isoxazole and indazol-4-one chemical classes have been discovered and are currently or soon to be in clinical trials for the treatment of cancer. In spite of a similar binding mode to Hsp90, distinct biological profiles were demonstrated among these molecules, both in vitro and in vivo.

Design of a flexible cell-based assay for the evaluation of heat shock protein 70 expression modulators.

Heat shock protein 70 (Hsp70) is a chaperone protein that helps protect against cellular stress, a function that may be co-opted to fight human diseases. In particular, the upregulation of Hsp70 can suppress the neurotoxicity of misfolded proteins, suggesting possible therapeutic strategies in neurodegenerative diseases. Alternatively, in cancer cells where high levels of Hsp70 inhibit both intrinsic and extrinsic apoptotic pathways, a reduction in Hsp70 levels may induce apoptosis.

Hsp90 inhibitor PU-H71, a multimodal inhibitor of malignancy, induces complete responses in triple-negative breast cancer models.

Triple-negative breast cancers (TNBCs) are defined by a lack of expression of estrogen, progesterone, and HER2 receptors. Because of the absence of identified targets and targeted therapies, and due to a heterogeneous molecular presentation, treatment guidelines for patients with TNBC include only conventional chemotherapy. Such treatment, while effective for some, leaves others with high rates of early relapse and is not curative for any patient with metastatic disease.

High-throughput screening fluorescence polarization assay for tumor-specific Hsp90.

Heat shock protein 90 (Hsp90) is a molecular chaperone that has emerged as an important target in cancer and several other diseases, such as neurodegenerative diseases, nerve injuries, inflammation, and infection. Discovery of novel agents that inhibit Hsp90 and have druglike properties is therefore a major focus in several academic and industrial laboratories. In this study, the authors describe the development and optimization in a 384-well format of a novel assay for the identification of Hsp90 inhibitors using fluorescence polarization, which measures competitive binding of red-shifted fluorescently labeled geldanamycin (GM-cy3B) to Hsp90 found in the NCI-N417 small-cell lung carcinoma cells.

Effects of herbal products and their constituents on human cytochrome P450(2E1) activity.

Ethanolic extracts from fresh Echinacea purpurea and Spilanthes acmella and dried Hydrastis canadensis were examined with regard to their ability to inhibit cytochrome P450(2E1) mediated oxidation of p-nitrophenol in vitro. In addition, individual constituents of these extracts, including alkylamides from E. purpurea and S.

Selective compounds define Hsp90 as a major inhibitor of apoptosis in small-cell lung cancer.

The heat shock protein 90 (Hsp90) has a critical role in malignant transformation. Whereas its ability to maintain the functional conformations of mutant and aberrant oncoproteins is established, a transformation-specific regulation of the antiapoptotic phenotype by Hsp90 is poorly understood. By using selective compounds, we have discovered that small-cell lung carcinoma is a distinctive cellular system in which apoptosis is mainly regulated by Hsp90.

Roles of heat-shock protein 90 in maintaining and facilitating the neurodegenerative phenotype in tauopathies.

Neurodegeneration, a result of multiple dysregulatory events, is a lengthy multistep process manifested by accrual of mutant variants and abnormal expression, posttranslational modification, and processing of certain proteins. Accumulation of these dysregulated processes requires a mechanism that maintains their functional stability and allows the evolution of the neurodegenerative phenotype. In malignant cells, the capacity to buffer transformation has been attributed to heat-shock protein 90 (Hsp90).

Synthesis of a red-shifted fluorescence polarization probe for Hsp90.

The synthesis of a red-shifted cy3B-GM ligand and its evaluation as a fluorescence polarization probe for Hsp90 is presented.