SUMMARY The evolution of prostate cancer from an androgen-dependent state (ADPCa) to one that is androgen-independent (AIPCa) marks its lethal progression. The androgen receptor (AR) is essential in both, though its function in AIPCa is poorly understood. We have defined the direct AR-dependent target genes in both AIPCa and ADPCa by generating AR-dependent gene expression profiles and AR cistromes. In contrast to ADPCa, AR selectively up-regulates M-phase cell cycle genes in AIPCa including UBE2C, a gene that inactivates the M-phase checkpoint. Selective epigenetic marks and collaborating transcription factor occupancy at UBE2C enhancers leads to increased AR recruitment and UBE2C over-expression in AIPCa cell lines and clinical cases. Silencing of UBE2C blocks AIPCa but not ADPCa growth. Thus the role of AR in AIPCa is not to direct the androgen-dependent gene expression program without androgen, but rather to execute a distinct program resulting in androgen-independent growth.

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature, is a complex multistage process regulated by a number of signal transduction pathways. Accumulating evidence suggests that signal transducer and activator of transcription (STATs), mainly STAT3, play an important role in angiogenesis under both physiological and pathological conditions in addition to cell survival, proliferation, differentiation, and oncogenesis. STAT3, as a critical multifunctional mediator, regulates many aspects of angiogenesis at the transcriptional level. This review will highlight the pivotal role of STAT3 in well-studied tumorous angiogenesis and cardiac angiogenesis, and summarize various potential mechanisms utilized by STAT3 to regulate the transcriptional activation of VEGF.

We found that bone morphogenetic protein (BMP) 7, a member of the BMP family, was strikingly up-regulated during the development of primary prostatic adenocarcinoma in the conditional Pten deletion mouse model. To determine the relevance of this finding to human prostate cancer, we examined the expression of BMPs and BMP receptors (BMPR) as well as the responsiveness to recombinant human BMP7 in a series of human prostate tumor cell lines. All prostatic cell lines tested expressed variable levels of BMP2, BMP4, and BMP7 and at least two of each type I and II BMPRs. In all cases, BMP7 induced Smad phosphorylation in a dose-dependent manner, with Smad5 activation clearly demonstrable. However, the biological responses to BMP7 were cell type specific. BPH-1, a cell line representing benign prostatic epithelial hyperplasia, was growth arrested at G 1 . In the bone metastasis-derived PC-3 prostate cancer cells, BMP7 induced epithelial-mesenchymal transdifferentiation with classic changes in morphology, motility, invasiveness, and molecular markers. Finally, BMP7 inhibited serum starvation-induced apoptosis in the LNCaP prostate cancer cell line and more remarkably in its bone metastatic variant C4-2B line. Each of the cell lines influenced by BMP7 was also responsive to BMP2 in a corresponding manner. The antiapoptotic activity of BMP7 in the LNCaP and C4-2B cell lines was not associated with a significant alteration in the levels of the proapoptotic protein Bax or the antiapoptotic proteins Bcl-2, Bcl-xl, and X-linked inhibitor of apoptosis. However, in C4-2B cells but not in LNCaP cells, a starvation-induced decrease in the level of survivin was counteracted by BMP7. Taken together, these findings suggest that BMPs are able to modulate the biological behavior of prostate tumor cells in diverse and cell type-specific manner and point to certain mechanisms by which these secreted signaling molecules may contribute to prostate cancer growth and metastasis. (Cancer Res 2005; 65(13): 5769-77)

Oxidized low density lipoprotein (OxLDL) is one of the most important risk factors of cardiovascular disease. Here, we study the impact of OxLDL on endothelial progenitor cells (EPCs) and determine whether OxLDL affects EPCs by an inhibitory effect on endothelial nitric oxide synthase (eNOS). It was found that OxLDL decreased EPC survival and impaired its adhesive, migratory, and tubeformation capacities in a dose-dependent manner. However, all of the detrimental effects of OxLDL were attenuated by pretreatment of EPCs with lectin-like oxidized low density lipoprotein receptor (LOX-1) monoclonal antibody or L-arginine. Western blot analysis revealed that OxLDL dosedependently decreased Akt phosphorylation and eNOS protein expression and increased LOX-1 protein expression. Furthermore, OxLDL caused a decrease in eNOS mRNA expression and an increase in LOX-1 mRNA expression. These data indicate that OxLDL inhibits EPC survival and impairs its function, and this action is attributable to an inhibitory effect on

The current concept of epigenetic repression is based on one repressor unit corresponding to one silent gene. This notion, however, cannot adequately explain concurrent silencing of multiple loci observed in large chromosome regions. The long-range epigenetic silencing (LRES) can be a frequent occurrence throughout the human genome. To comprehensively characterize the influence of estrogen signaling on LRES, we analyzed transcriptome, methylome, and estrogen receptor alpha (ESR1)-binding datasets from normal breast epithelia and breast cancer cells. This “omics” approach uncovered 11 large repressive zones (range, 0.35∼5.98 megabases), including a 14-gene cluster located on 16p11.2. In normal cells, estrogen signaling induced transient formation of multiple DNA loops in the 16p11.2 region by bringing 14 distant loci to focal ESR1-docking sites for coordinate repression. However, the plasticity of this free DNA movement was reduced in breast cancer cells. Together with the acquisition of DNA methylation and repressive chromatin modifications at the 16p11.2 loci, an inflexible DNA scaffold may be a novel determinant used by breast cancer cells to reinforce estrogen-mediated repression.

Glucocorticoids (GC) have been widely used as coadjuvants in the treatment of solid tumors, but GC treatment may be associated with poor pharmacotherapeutic response or prognosis. The genomic action of GC in these tumors is largely unknown. Here we find that dexamethasone (Dex, a synthetic GC) regulated genes in triple-negative breast cancer (TNBC) cells are associated with drug resistance. Importantly, these GC-regulated genes are aberrantly expressed in TNBC patients and associated with unfavorable clinical outcomes. Interestingly, in TNBC cells, Compound A (CpdA, a selective GR modulator) only regulates a small number of genes not involved in carcinogenesis and therapy resistance. Mechanistic studies using a ChIP-exo approach reveal that Dex- but not CpdA-liganded glucocorticoid receptor (GR) binds to a single glucocorticoid response element (GRE), which drives the expression of pro-tumorigenic genes. Our data suggest that development of safe coadjuvant therapy should consider the distinct genomic function between Dex- and CpdA-liganded GR.

The application of Cre/loxP technology has resulted in a new generation of conditional mouse models of prostate cancer. Here, we describe the improvement of the conditional Pten deletion model of prostate adenocarcinoma by combining it with either a conditional luciferase or enhanced green fluorescent protein reporter line. In these models, the recombination mechanism that inactivates the Pten alleles also activates the reporter gene. In the luciferase reporter model, the growth of the primary cancer can be followed noninvasively by bioluminescence imaging (BLI). Surgical castration of tumor-bearing animals leads to a reduced bioluminescence signal corresponding to tumor regression that is verified at necropsy. When castrated animals are maintained, the emergence of androgen depletion-independent cancer is detected using BLI at times varying from 7 to 28 weeks postcastration. The ability to monitor growth, regression, or relapse of the tumor with the use of BLI lead to the collection of tumors at different stages of development. By comparing the distribution of phenotypically distinct populations of epithelial cells in cancer tissues, we noted that the degree of hyperplasia of cells with neuroendocrine differentiation significantly increases in the recurrent cancer relative to the primary cancer, a characteristic which may parallel the appearance of a neuroendocrine phenotype in human androgen depletion-independent cancer. The enhanced green fluorescent protein model, at necropsy, can provide an opportunity to locate or assess tumor volume or to isolate enriched populations of cancer cells from tumor tissues via fluorescence-based technologies. These refined models should be useful in the elucidation of mechanisms of prostate cancer progression, and for the development of approaches to preclinical intervention. [Cancer Res 2007; 67(15):7525-33]

Klebsiella pneumoniae bacteremia biofilm traits and distribution characteristics have not been clarified. This study aimed to determine the prevalence and characteristics of K. pneumoniae bacteremia biofilm formation (BF) and to explore the virulence factors associated with K. pneumoniae BF. A total of 250 K. pneumoniae bacteremia isolates were collected from patients in Shenzhen and Shanghai, China. Virulence genes in their genomes were detected by PCR. The isolates were subjected to multilocus sequence typing (MLST) and clonal complex (CC) classification based on housekeeping genes. Biofilms were detected by crystal violet staining. Greater BF was observed in isolates from young adults (<40 years old) than in those from seniors (≥65 years old; P = 0.002). MLST yielded 65 different sequence types (STs), with the most represented STs being ST11, ST23, and ST65, and the main CCs were CC23 and CC65; CC23 isolates exhibited greater BF than CC65 or ST11 isolates (both P < 0.001). BF was more pronounced among magA(K1), aero+, rmpA+, rmpA2+, allS+, wcaG+, and iutA+ isolates than in isolates that were negative for these virulence factors. Multivariate regression analysis revealed only wcaG as an independent risk factor for BF (odds ratio 11.426, P < 0.001), and BF was decreased when wcaG was silenced by antisense RNA. In conclusion, BF in K. pneumoniae bacteremia isolates was found to be associated with CC23 classification and the presence of the wcaG virulence factor gene.