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Hormone Refractory Prostate Cancer (hormone + refractory_prostate_cancer)
Selected AbstractsEffects of flutamide as a second-line agent for maximum androgen blockade of hormone refractory prostate cancerINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2007Kenji Nishimura Abstract: We analyzed clinical effects of flutamide as a second-line agent for maximum androgen blockade (MAB) in patients with relapsing prostate cancer who received bicalutamide as the first-line MAB agent. This study included 13 patients with progressive prostate cancer who had relapsed after first-line MAB, with bicalutamide at 80 mg/day. After checking for antiandrogen withdrawal syndrome, they were given flutamide at 375 mg/day as second-line MAB. The effectiveness of that therapy was evaluated by changes in prostatic specific antigen (PSA) levels, with response defined as a decrease of greater than 50% from the start of therapy. We also compared several factors between responders and non-responders. Nine (69.2%) of the 13 patients showed a decrease in PSA levels, of whom five (38.5%) had a greater than 50% decrease and were defined as responders. The median duration of PSA response was 11.0 months (range 5,20 months). Patients who had a longer duration of response to first-line MAB had a significantly greater response to second-line MAB. For advanced prostate cancer patients who progressed on first-line MAB with bicalutamide, flutamide administration as a second-line antiandrogen was found to be relatively effective, especially for those who showed a longer duration of response to the first-line MAB. Our results confirm previous findings that MAB using flutamide is an effective second-line hormonal therapy. [source] Decrease in stromal androgen receptor associates with androgen-independent disease and promotes prostate cancer cell proliferation and invasionJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 6b 2008Yirong Li Abstract Androgen receptor (AR) is expressed in both stromal and epithelial cells of the prostate. The majority of studies on AR expression and function in prostate cancer is focused on malignant epithelial cells rather than stromal cells. In this study, we examined the levels of stromal AR in androgen-dependent and -independent prostate cancer and the function of stromal AR in prostate cancer growth and invasion. We showed that stromal AR levels were decreased in the areas surrounding cancerous tissue, especially in androgen-independent cancer. Using two telomerase-immortalized human stromal cell lines, one AR-positive and the other AR-negative, we demonstrated that stromal cells lacking AR stimulated cell proliferation of co-cultured prostate cancer cells in vitro and enhanced tumour growth in vivo when co-injected with PC3 epithelial cells in nude mice. In contrast, stromal cells expressing AR suppressed prostate cancer growth in vitro and in vivo. In parallel with cancer growth, in vitro invasion assays revealed that stromal cells lacking AR increased the invasion ability of PC3 cell by one order of magnitude, while stromal cells expressing AR reduced this effect. These results indicate a negative regulation of prostate cancer growth and invasion by stromal AR. This provides potentially new mechanistic insights into the failure of androgen ablation therapy, and the reactivation of stromal AR could be a novel therapeutic approach for treating hormone refractory prostate cancer. [source] Allogeneic retrovirally transduced, IL-2- and IFN-,-secreting cancer cell vaccine in patients with hormone refractory prostate cancer,a phase I clinical trialTHE JOURNAL OF GENE MEDICINE, Issue 7 2007T. H. Brill Background The purpose of this vaccine study was to determine the safety and feasibility of vaccination with an allogeneic prostate carcinoma cell line, LNCaP, expressing recombinant interleukin-2 (IL-2) and interferon-, (IFN-,) and to evaluate the efficacy of inducing tumor-specific immune responses in HLA-A2-matched patients with hormone refractory prostate cancer (HRPC). Methods In a dose-escalating phase I study, HLA-A2-matched HRPC patients received four vaccinations of irradiated allogeneic LNCaP cells retrovirally transduced to secrete IL-2 and IFN-, at study day 1, 15, 29 and 92 and subsequently every 91 days unless tumor progression was evident. Results Three patients receiving the first dose level (7.5 million cells) showed no evidence of dose-limiting toxicity or vaccine-related adverse events including autoimmunity. One of three patients receiving the second dose level (15 million cells) developed a transient self-limiting grade 3 local injection site reaction (ulceration) after the eighth vaccination. Vaccine-induced immune responses against a broad array of prostate tumor associated antigens were detected in all six patients. Two of the three patients receiving the higher dose showed a decline in serum prostate-specific antigen (PSA) values of more than 50%, with one patient remaining on protocol for 3 years. Conclusions Immunisation with the allogeneic LNCaP/IL-2/IFN-, vaccine is safe and feasible without any dose-limiting toxicity or autoimmunity. A 50% PSA decline was achieved in two of the six patients. This encouraging data provides the scientific rationale for further investigation of the vaccine in a phase II trial. Copyright © 2007 John Wiley & Sons, Ltd. [source] Molecular characterization of the G,-globin-Tag transgenic mouse model of hormone refractory prostate cancer: Comparison to human prostate cancer,THE PROSTATE, Issue 6 2010Alfonso Calvo Abstract BACKGROUND Prostate cancer (PrCa) has a high incidence in Western countries and at present, there is no cure for hormone refractory prostate cancer. Transgenic mouse models have proven useful for understanding mechanisms of prostate carcinogenesis. The characterization of genetically modified mouse PrCa models using high-throughput genomic analyses provides important information to guide appropriate experiment applications for such model. METHODS We have analyzed the transcriptome of the hormone refractory and highly metastatic Fetal Globin-SV40/T-antigen (G,-globin-Tag) transgenic mouse model for PrCa compared to normal mouse prostate tissue. Gene expression patterns found in G,-globin-Tag mouse prostate tumors were compared with publicly available human localized and metastatic prostate tumors (GEO accession # GSE3325) through hierarchical cluster analysis, Pearson's rank correlation coefficient, and Self Organizing Feature Maps (SOM) analyses. RESULTS G,-globin-Tag tumors clustered closely with human metastatic tumors and gene expression patterns had a significant correlation (P,<,0.01), unlike human localized primary tumors (P,>,0.6). Bioinformatic analyses identified deregulated genetic pathways and networks in G,-globin-Tag tumors, which displayed similarities to alterations in human PrCa. Changes in the expression of genes involved in DNA replication and repair (Rb1, p53, Myc, PCNA, DNMT3A) and growth factor signaling pathways (TGF,2, ERK1/2, NRas, and Notch1) are deregulated in the G,-globin-Tag tumors, suggesting their key role in the oncogenic process. Identification of an enrichment of putative binding sites for transcription factors revealed eight transcription factors that may be important in G,-globin-Tag carcinogenesis, including SP1, NF-Y, CREB, Elk1, and E2F. Novel genes related to microtubule regulation were also identified in G,-globin-Tag tumors as potentially important candidate targets for PrCa. Overexpression of stathmin-1, whose expression was increased in human metastatic prostate tumors, was validated in G,-globin-Tag tumors by immunohistochemistry. This protein belongs to the SV40/T-antigen cancer signature identified in previous studies in prostate, breast, and lung cancer mouse models. CONCLUSIONS Our results show that the G,-globin-Tag model for hormone refractory PrCa shares important features with aggressive, metastatic human PrCa. Given the role of stathmin-1 in the destabilization of microtubles and taxane resistance, the G,-globin-Tag model and other SV40/T-antigen driven transgenic models may be useful for testing potential therapies directed at stathmin-1 in human prostate tumors. Prostate 70: 630,645, 2010. Published 2010 Wiley-Liss, Inc. [source] 2-Chloroadenosine modulates PAR-1 and IL-23 expression and enhances docetaxel effects on PC3 cellsTHE PROSTATE, Issue 4 2008Alba Minelli Abstract BACKGROUND Docetaxel-based chemotherapy is the only treatment that demonstrated an overall survival benefit in men with hormone refractory prostate cancer. 2-CADO inhibits the growth of PC3 cells by inducing apoptosis and cell cycle arrest through a mechanism that involves cellular uptake. METHODS Androgen-independent and -sensitive (PC3 and LNCaP) prostate cancer cells and non-neoplastic HECV cells were used in the study. Proliferation and cell cycle progression were analyzed in the presence of 2-CADO and Docetaxel. Invasive potential was assessed by soft agar assay and metastatic ability by adhesion assay. IL-23 and PAR-1 expression were determined by real time PCR. RESULTS 2-CADO pre-treatment followed by Docetaxel at subclinical dosage reduced the viability of either PC3 or LNCaP while it did not enhance Docetaxel-induced cytotoxicity in adherent non-neoplastic HECV. The drugs reduced the invasive potential of PC3 cells by inducing apoptosis and blocking cell cycle progression in the S-phase. Down-regulation of PAR-1 gene expression resulted in a slightly lower metastatic potential, whereas up-regulation of IL-23 induced the activation of the immune system. CONCLUSIONS Pretreatment of PC3 cells with 2-CADO decreased the effective concentration of Docetaxel, lowered the metastatic potential, and induced the production of cytokines known to stimulate the immune response against cancer. The treatment was effective for prostate cancer cells independently on their androgen sensitiveness. Prostate 68: 360,372, 2008. © 2008 Wiley-Liss, Inc. [source] Interleukin-6 protects LNCaP cells from apoptosis induced by androgen deprivation through the Stat3 pathwayTHE PROSTATE, Issue 3 2004Soo Ok Lee Abstract BACKGROUND Elevated expression of interleukin-6 (IL-6) is implicated in the progression of hormone refractory prostate cancer. Previous studies demonstrated that IL-6 promotes androgen-independent growth of prostate cancer cells. In this study, the effect of IL-6 on apoptosis induced by androgen deprivation was investigated. METHODS The effect of IL-6 on apoptosis induced by androgen deprivation in LNCaP cells was examined by cell death ELISA and Western blot using cleaved poly (ADP-ribose) polymerase (PARP) and caspase-9, as well as Bcl-xL and phosphorylated Bad. The Stat3 in IL-6-mediated anti-apoptosis in prostate cancer cells was examined using either dominant-negative or constitutively activated Stat3 mutants. RESULTS Overexpression of IL-6 renders androgen sensitive LNCaP human prostate cancer cells more resistant to apoptosis induced by androgen deprivation. LNCaP cells undergo apoptosis after 72 hr of androgen deprivation, an outcome is largely absent in clones overexpressing IL-6 as measured by cell death ELISA and chromatin degradation assays. IL-6 over-expressing cells resulted in a significant decrease in the expression of cleaved PARP and cleaved caspase-9 as well as an increase in the expression of Bcl-xL and phosphorylated Bad. Addition of IL-6 antibody completely abolished the anti-apoptotic activity of IL-6. This protective effect of IL-6 was reversed by the expression of a dominant-negative Stat3 mutant, Stat3F. Furthermore, ectopic expression of a constitutively active Stat3 antagonized androgen deprivation-induced cell death of LNCaP cells. CONCLUSION These results indicate that IL-6 protects androgen sensitive LNCaP cells from apoptosis induced by androgen deprivation, and Stat3 activation play an important role in IL-6-mediated anti-apoptosis in prostate cancer cells. © 2004 Wiley-Liss, Inc. [source] | ||||||||||