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BACKGROUND The TMPRSS2-ERG gene fusion is detected in approximately half of primary prostate cancers (PCa) yet the prognostic significance remains unclear. We hypothesized that ERG promotes the expression of common genes in primary PCa and metastatic castration-resistant PCa (CRPC), with the objective of identifying ERG-associated pathways, which may promote the transition from primary PCa to CRPC. METHODS We constructed tissue microarrays (TMA) from 127 radical prostatectomy specimens, 20 LuCaP patient-derived xenografts (PDX), and 152 CRPC metastases obtained immediately at time of death. Nuclear ERG was assessed by immunohistochemistry (IHC). To characterize the molecular features of ERG-expressing PCa, a subset of IHC confirmed ERG+ or ERG− specimens including 11 radical prostatectomies, 20 LuCaP PDXs, and 45 CRPC metastases underwent gene expression analysis. Genes were ranked based on expression in primary PCa and CRPC. Common genes of interest were targeted for IHC analysis and expression compared with biochemical recurrence (BCR) status. RESULTS IHC revealed that 43% of primary PCa, 35% of the LuCaP PDXs, and 18% of the CRPC metastases were ERG+ (12 of 48 patients [25%] had at least one ERG+ metastasis). Based on gene expression data and previous literature, two proteins involved in calcium signaling (NCALD, CACNA1D), a protein involved in inflammation (HLA-DMB), CD3 positive immune cells, and a novel ERG-associated protein, DCLK1 were evaluated in primary PCa and CRPC metastases. In ERG+ primary PCa, a weak association was seen with NCALD and CACNA1D protein expression. HLA-DMB association with ERG was decreased and CD3 cell number association with ERG was changed from positive to negative in CRPC metastases compared to primary PCa. DCLK1 was upregulated at the protein level in unpaired ERG+ primary PCa and CRPC metastases (P = 0.0013 and P

Background Osteosarcoma (OS) is a primary malignant tumor of the bone that typically presents in the second decade of life and has a poor prognosis, especially in metastatic cases. Wnt signaling contributes to the pathogenesis of tumors such as colon cancer and malignant melanoma. Wnt signaling controls normal bone formation during embryogenesis and homeostasis in adult organisms, thus we evaluated Wnt signaling in OS. Procedure We surveyed the expression of Wnts, their receptors, Frizzleds and LRPs, and soluble Wnt inhibitors (sFRPs) in four OS cell lines by RT-PCR. We also tested biological response of OS cell lines to exogenous Wnts by measuring β-catenin stabilization, Dvl phosphorylation, TOPFLASH activity and chemotaxis. Human OS tumor microarrays were evaluated for expression of Wnt10b by immunohistochemistry. Results All cell lines tested showed expression of at least three Wnts and one Frizzled. Exogenous Wnt3a and Wnt10b treatment induced Dvl phosphorylation, β-catenin stabilization and TCF4 transcriptional activity in both metastatic and non-metastatic murine OS cell lines. Metastatic OS cell lines showed better chemotaxis response to Wnts than the non-metastatic OS cell lines. Immunohistochemistry studies of 44 human OS samples demonstrated that Wnt10b expression correlated with decreased overall survival. Conclusions These results further supports a possible autocrine or paracrine Wnt pathway in metastatic potential of OS. Pediatr Blood Cancer 2008;51:349–355. © 2008 Wiley-Liss, Inc.

Background The Ewing sarcoma family of tumors (ESFT) is a set of neuroectodermal malignancies that typically presents in the second decade and has a poor prognosis due to metastatic disease. Wnt signaling has a critical role in the normal development of multiple neuroectodermal tissues and also contributes to the neoplastic properties of tumor cells of neuroectodermal origin. Procedure We surveyed the expression of Wnts and their receptors in nine ESFT cell lines by RT-PCR analysis. We also tested biological response of ESFT cell lines to exogenous Wnts in β-catenin stabilization, actin stress fiber formation, and chemotaxis assays. Results We detected Wnt-10b in all the lines, and most also expressed Wnt-5a, Wnt-11, and Wnt-13. Several Frizzleds (Fz) and the Wnt co-receptors, low density lipoprotein-receptor-like proteins 5 and 6 were also expressed. We observed a marked stimulation of the β-catenin/canonical Wnt pathway in ESFT cells treated with Wnt-3a. Wnt-3a induced morphologic changes characterized by the formation of long cytoplasmic extensions in ESFT cells. We also observed chemotaxis of ESFT cells in response to Wnt-3a. Conclusions These results provide evidence that components of Wnt/Fz pathway are expressed and an intact Wnt/Frizzled signaling pathway exists in ESFT cell lines. Activation of the Wnt pathway in ESFT suggests that Wnt modulates cell motility rather than cell proliferation. Hence, activation of this pathway may influence metastatic potential of ESFT. © 2004 Wiley-Liss, Inc.

Background and Purpose HIV-1 transcription is activated by the Tat protein which recruits the cyclin-dependent kinase CDK9/cyclin T1 to TAR RNA. Tat binds to protein phosphatase-1 (PP1) through the Q35VCF38 sequence and translocates PP1 to the nucleus. PP1 dephosphorylates CDK9 and activates HIV-1 transcription. We have synthesized a low MW compound 1H4, that targets PP1 and prevents HIV-1 Tat interaction with PP1 and inhibits HIV-1 gene transcription. Here, we report our further work with the 1H4-derived compounds and analysis of their mechanism of action.