In vivo effects of the human type I insulin-like growth factor receptor antibody A12 on androgen-dependent and androgen-independent xenograft human prostate tumors.

PURPOSE: The type I insulin-like growth factor receptor (IGF-IR) and its ligands have been shown to play a critical role in prostate carcinoma development, growth, and metastasis. Targeting the IGF-IR may be a potential treatment for prostate cancer. A fully human monoclonal antibody, A12, specific to IGF-IR, has shown potent antitumor effects in breast, colon, and pancreatic cancers in vitro and in vivo. In this study, we tested the in vivo effects of A12 on androgen-dependent and androgen-independent prostate tumor growth. EXPERIMENTAL DESIGN: Androgen-dependent LuCaP 35 and androgen-independent LuCaP 35V prostate tumors were implanted s.c. into intact and castrated severe combined immunodeficient mice, respectively. When tumor volume reached about 150 to 200 mm(3), A12 was injected at 40 mg/kg body weight thrice a week for up to 5 weeks. RESULTS: We find that A12 significantly inhibits growth of androgen-dependent LuCaP 35 and androgen-independent LuCaP 35V prostate xenografts, however, by different mechanisms. In LuCaP 35 xenografts, A12 treatment induces tumor cell apoptosis or G(1) cycle arrest. In LuCaP 35V xenografts, A12 treatment induces tumor cell G(2)-M cycle arrest. Moreover, we find that blocking the function of IGF-IR down-regulates androgen-regulated gene expression in androgen-independent LuCaP 35V tumor cells. CONCLUSIONS: Our findings suggest that A12 is a therapeutic candidate for both androgen-dependent and androgen-independent prostate cancer. Our findings also suggest an IGF-IR-dependent activity of the androgen receptor in androgen-independent prostate cancer cells.     

Honokiol, a constituent of oriental medicinal herb magnolia officinalis, inhibits growth of PC-3 xenografts in vivo in association with apoptosis induction.

PURPOSE: This study was undertaken to determine the efficacy of honokiol, a constituent of oriental medicinal herb Magnolia officinalis, against human prostate cancer cells in culture and in vivo. EXPERIMENTAL DESIGN: Honokiol-mediated apoptosis was assessed by analysis of cytoplasmic histone-associated DNA fragmentation. Knockdown of Bax and Bak proteins was achieved by transient transfection using siRNA. Honokiol was administered by oral gavage to male nude mice s.c. implanted with PC-3 cells. Tumor sections from control and honokiol-treated mice were examined for apoptotic bodies (terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay), proliferation index (proliferating cell nuclear antigen staining), and neovascularization (CD31 staining). Levels of Bcl-2 family proteins in cell lysates and tumor supernatants were determined by immunoblotting. RESULTS: Exposure of human prostate cancer cells (PC-3, LNCaP, and C4-2) to honokiol resulted in apoptotic DNA fragmentation in a concentration- and time-dependent manner irrespective of their androgen responsiveness or p53 status. Honokiol-induced apoptosis correlated with induction of Bax, Bak, and Bad and a decrease in Bcl-xL and Mcl-1 protein levels. Transient transfection of PC-3 cells with Bak- and Bax-targeted siRNAs and Bcl-xL plasmid conferred partial yet significant protection against honokiol-induced apoptosis. Oral gavage of 2 mg honokiol/mouse (thrice a week) significantly retarded growth of PC-3 xenografts without causing weight loss. Tumors from honokiol-treated mice exhibited markedly higher count of apoptotic bodies and reduced proliferation index and neovascularization compared with control tumors. CONCLUSION: Our data suggest that honokiol, which is used in traditional oriental medicine for the treatment of various ailments, may be an attractive agent for treatment and/or prevention of human prostate cancers.     

TabBO: a model reflecting common molecular features of androgen-independent prostate cancer.

We established two human prostate cancer cell lines, MDA PCa 2a and MDA PCa 2b, the TabBO model system, that reflect common features of human androgen-independent prostate cancer that are not present in other model systems: bone origin, prostate-specific antigen production, androgen receptor expression, and androgen sensitivity. We therefore hypothesized that molecular pathways in our model system reflect common alterations responsible for the progression of a subset of human prostate cancer. Progression to androgen independence has been hypothesized to be largely associated with impairment of the regulation of cell growth or apoptosis of prostate cancer cells. Therefore, in this study, we examined molecular markers known or suspected to be important in prostate cancer progression and key regulators of cell growth and apoptosis: p53, p21WAF1/CIP1, Bcl-2, Bax, retinoblastoma (Rb), and p16INK4A/MITS1. We analyzed the expression of these markers in the cell lines, their tumor of origin, and tumors derived from the cell lines by s.c. inoculation into nude mice. DNA sequencing of the entire open reading frames of the p53 and p21 genes revealed no mutations. Additionally, accumulation of the p53 protein was not found by Western blot analysis, nor was overexpression of the Bcl-2 oncoprotein detected. Bax expression was detected in MDA PCa 2a cells, whereas it was absent in MDA PCa 2b. Rb and p16 protein expression was normal as measured by both Western blot and immunochemical analyses. Immunohistochemical studies of p53, p21, Bcl-2, and Rb in both samples from the original human cancer from which the lines were derived and mouse xenografts derived from the lines revealed similar levels of protein. These results are consistent with reports indicating that 40-50% of bone metastases of prostate cancer have wild-type p53, 50-70% do not overexpress the Bcl-2 protein, and mutations in the p21 gene are rare. Therefore, we conclude that MDA PCa 2a and MDA PCa 2b reflect molecular pathways in a common subset of human androgen-independent prostate cancer and that important molecular players in apoptosis (namely, p53 and Bcl-2) seem to be intact in this subset of androgen-independent prostate cancer. Understanding the signal-transduction pathways operating in these cell lines may help to identify therapeutic targets for prostate cancer.     

BKM1740, an acyl-tyrosine bisphosphonate amide derivative, inhibits the bone metastatic growth of human prostate cancer cells by inducing apoptosis

PURPOSE: Survivin overexpression has been associated with an unfavorable outcome in human PCa; however, its role in metastasis remains elusive. We aim to (a) evaluate the clinical implications of survivin expression in PCa bone metastasis; (b) determine in vivo efficacy of BKM1740, a small-molecule compound, against PCa skeletal growth and survival; and (c) investigate molecular mechanism by which BKM1740 augments apoptosis in bone metastatic PCa cells. EXPERIMENTAL DESIGN: Survivin expression was analyzed in PCa specimens and experimental models. Bone metastatic C4-2 and ARCaP(M) cell lines were used to evaluate the in vitro effects of BKM1740 and molecular mechanism for the induction of apoptosis. C4-2 cells were grown intratibially in athymic nude mice to evaluate the in vivo efficacy of BKM1740. Tumor growth in mouse bone was assessed by serum prostate-specific antigen and radiography and confirmed by immunohistochemical analyses. RESULTS: Survivin expression is positively associated with clinical PCa bone metastasis. BKM1740 induced apoptosis in PCa cells by repressing survivin. Mice with established C4-2 tumors in tibia showed a marked decrease in serum prostate-specific antigen and much improved bone architecture radiographically after treatment with BKM1740. Immunohistochemical assays of mouse tumor samples confirmed that the in vivo effects were mediated by inhibition of survivin and induction of apoptosis. CONCLUSIONS: Survivin expression is associated with PCa bone metastasis. BKM1740 treatment specifically inhibited survivin and induced apoptosis in vitro and was efficacious in retarding PCa skeletal growth in a mouse model. BKM1740 is a promising small-molecule compound that could be used to treat PCa bone metastasis.     

Chitosan nanoparticle-mediated delivery of miRNA-34a decreases prostate tumor growth in the bone and its expression induces non-canonical autophagy

While several new therapies are FDA-approved for bone-metastatic prostate cancer (PCa), patient survival has only improved marginally. Here, we report that chitosan nanoparticle-mediated delivery of miR-34a, a tumor suppressive microRNA that downregulates multiple gene products involved in PCa progression and metastasis, inhibited prostate tumor growth and preserved bone integrity in a xenograft model representative of established PCa bone metastasis. Expression of miR-34a induced apoptosis in PCa cells, and, in accord with downregulation of targets associated with PCa growth, including MET and Axl and c-Myc, also induced a form of non-canonical autophagy that is independent of Beclin-1, ATG4, ATG5 and ATG7. MiR-34a-induced autophagy is anti-proliferative in prostate cancer cells, as blocking apoptosis still resulted in growth inhibition of tumor cells. Thus, combined effects of autophagy and apoptosis are responsible for miR-34a-mediated prostate tumor growth inhibition, and have translational impact, as this non-canonical form of autophagy is tumor inhibitory. Together, these results provide a new understanding of the biological effects of miR-34a and highlight the clinical potential for miR-34a delivery as a treatment for bone metastatic prostate cancer.     

FTY720, a fungus metabolite, inhibits in vivo growth of androgen-independent prostate cancer

FTY720, a derivative of fungus, has demonstrated dramatic anticancer effect in several malignancies recently. Our study evaluates the therapeutic potential of FTY720 in the treatment of androgen-independent prostate cancer using a human prostate cancer xenograft in nude mice. CWR22R, an androgen-independent human prostate tumor xenograft was inoculated into castrated nude mice and the animals were administrated with either normal saline or FTY720 (10 mg/kg) through intraperitoneal (i.p.) injection for 20 days. Body weight and tumor volume were recorded every 2 days, and serum prostate specific antigen (PSA) levels were also measured before and after the treatment. The effect of FTY720 on tumor cell proliferation was examined using antibodies against PCNA and Ki-67 by immunohistochemical staining, MTT assay and colony forming assay, whereas apoptotic effect of FTY720 was evaluated by TUNEL assay and immunostaining using antibodies against cleaved caspase 3 and Bcl-2. In addition, the potential inhibitory effect of FTY720 on prostate cancer angiogenesis and metastasis was investigated by immunostaining of CD31, VEGF, E-cadherin and beta-catenin. Our results showed that FTY720 treatment led to suppression of CWR22R tumor growth without causing any detectable side effects in nude mice. The FTY720-induced tumor suppression was correlated with decreased serum PSA level as well as reduced proliferation rate, suppression of angiogenic factors, and restoration of E-cadherin and beta-catenin expression. In addition, the FTY720-treated tumors showed increased apoptosis rate demonstrated by increased TUNEL- and cleaved caspase 3-positive cells, and decreased Bcl-2 expression. Our results suggest a potential novel agent in the suppression of androgen-independent prostate cancer.     

Down-regulation of c-Src/EGFR-mediated signaling activation is involved in the honokiol-induced cell cycle arrest and apoptosis in MDA-MB-231 human breast cancer cells

Honokiol is a naturally occurring neolignan abundant in Magnoliae Cortex and has showed anti-proliferative and pro-apoptotic effects in a wide range of human cancer cells. However, the molecular mechanisms on the anti-proliferative activity in cancer cells have been poorly elucidated. In this study, we evaluated the growth inhibitory activity of honokiol in cultured estrogen receptor (ER)-negative MDA-MB-231 human breast cancer cells. Honokiol exerted anti-proliferative activity with the cell cycle arrest at the G0/G1 phase and sequential induction of apoptotic cell death in a concentration-dependent manner. The honokiol-induced cell cycle arrest was well correlated with the suppressive expression of CDK4, cyclin D1, CDK2, cyclin E, c-Myc, and phosphorylated retinoblastoma protein (pRb) at Ser780. Apoptosis caused by honokiol was also concomitant with the cleavage of caspases (caspase-3, -8, and -9) and Bid along with the suppressive expression of Bcl-2, but it was independent on the expression of Bax and p53. In addition, honokiol-treated cells exhibited the cleavage of poly (ADP-ribose) polymerase (PARP) and DNA fragmentation. In the analysis of signal transduction pathway, honokiol down-regulated the expression and phosphorylation of c-Src, epidermal growth factor receptor (EGFR), and Akt, and consequently led to the inactivation of mTOR and its downstream signal molecules including 4E-binding protein (4E-BP) and p70 S6 kinase. These findings suggest that honokiol-mediated inhibitory activity of cancer cell growth might be related with the cell cycle arrest and induction of apoptosis via modulating signal transduction pathways.     

Expression of matrix metalloproteinase-2 and prostate-specific antigen in localized and metastatic prostate cancer

BACKGROUND: The matrix metalloproteinases (MMP)-2 and MMP-9 are known to degrade the extra-cellular matrix (ECM) and to be involved in the invasion and metastasis of cancer cells. In order to establish the clinical significance of the determination of serum MMP-2 levels for prostate cancer (PCa), we determined serum levels of MMP-2 and PSA in patients with PCa at different stages. PATIENTS AND METHODS: In this study, serum samples from 39 patients with prostate hypertrophy and 51 PCa patients diagnosed at Kitasato University Hospital, Japan, were examined. MMP-2 levels were determined by measuring pro-MMP-2 using an enzyme immunoassay. PSA was also determined by enzyme immunoassay. Immunohistochemical analysis of prostate cancer specimens was performed according to the labeled streptavidin-biotinylated antibody (LSAB) method. RESULTS: Serum levels of MMP-2 and PSA increased with PCa disease progression. Serum levels of both markers in patients with invasive and metastatic PCa were significantly higher than in those with localized PCa. No significant association was found between serum levels of MMP-2 and PSA in patients with PCa. Extremely high levels of MMP-2 greater than 950 ng/ml or increased levels of PSA over 300 ng/ml were found only in PCa patients with bone metastases. CONCLUSION: Our findings indicate that MMP-2 may be involved in the invasion and metastasis of PCa and that serum MMP-2 levels may be able to become an auxiliary indicator of serum PSA to detect the progression of PCa.     

前列腺癌ADC值与血清IL-6、VEGF、PSA的相关性分析

目的:探讨前列腺癌（prostate cancer,PCa）患者表观扩散系数（apparent diffusion coefficient,ADC）与血清血管内皮生长因子（vascular endothelial growth factor,VEGF)、白细胞介素-6（interleukin-6,IL-6）、前列腺特异性抗原（prostate specific antigen,PSA）的相关性。方法:收集2016年1月至2017年12月经临床病理证实且资料齐全的60例PCa患者,将其分成两组,经SPECT/CT全身骨显像诊断为30例骨转移患者及30例未发生全身骨转移患者。采集全部患者的肘静脉血,利用酶联免疫吸附法（ELISA法）及化学发光法测定血清VEGF、IL-6及PSA水平。结果:60例PCa患者ADC值与血清VEGF、IL-6及PSA存在负相关(r=-0.431,P=0.001＜0.005;r=-0.534,P=0.000<0.005;r=-0.593,P=0.000＜0.005),骨转移组血清VEGF、IL-6及PSA水平明显高于无骨转移组（P＜0.05）。结论:血清VEGF、IL-6及PSA与PCa发生、进展及转移关系密切。PCa患者ADC值与血清VEGF、IL-6、PSA的相关性可以作为评估患者病情进展程度的一个指标。     

Inhibition of angiogenesis by the antiepidermal growth factor receptor antibody ImClone C225 in androgen-independent prostate cancer growing orthotopically in nude mice.

In human androgen-independent prostate cancer (PCa), epidermal growth factor receptor (EGFR) regulates angiogenesis, tumor growth, and progression. In this study, we evaluated whether the blockade of EGFR by the anti-EGFR antibody ImClone C225 (IMC-C225) inhibited tumor growth and metastasis by inhibiting angiogenesis, and whether paclitaxel enhanced the results of therapy in androgen-independent PCa. PC-3M-LN4 PCa cells were implanted orthotopically in athymic nude mice and treated with i.p. IMC-C225 (1 mg twice a week) and/or paclitaxel (200 microg once a week). In vitro treatment of PC-3M-LN4 with IMC-C225 inhibited EGFR autophosphorylation without any significant antiproliferative effect. In contrast, in vivo therapy with IMC-C225 alone (P < 0.05) or in combination with paclitaxel (P < 0.005) significantly inhibited PCa growth and metastasis. Serum levels of interleukin (IL) 8 were lower after therapy, and IL-8 mRNA expression was down-regulated within the tumors after therapy. The down-regulation of IL-8 correlated with reduced microvessel density. IMC-C225 reduced tumor cell proliferation, enhanced p27(kip1) expression, and induced tumor and endothelial cell apoptosis. These studies indicate that IMC-C225 has significant antitumor effect in this murine model, mediated in part by inhibition of cellular proliferation and angiogenesis, and by enhancement of apoptosis. The simultaneous administration of paclitaxel enhanced this effect.     

Synergistic inhibition of tumor growth and metastasis by combined treatment with TNP-470 and docetaxel in a human prostate cancer PC-3 model

TNP-470, a potent inhibitor of angiogenesis, was reported to synergistically enhance the antitumor effects of cytotoxic agents. The objective of this study was to evaluate the effectiveness of combined treatment with TNP-470 and docetaxel both in vitro and in vivo using androgen-independent human prostate cancer PC-3 cells. The in vitro growth-inhibitory and apoptotic effects of docetaxel and/or TNP-470 on PC-3 cells were assessed using MTT and TUNEL assays. The combined effect of docetaxel and TNP-470 therapy after subcutaneous and orthotopic injection of PC-3 cells into athymic nude mice was evaluated. In vivo effects of this combined regimen on PC-3 tumors were analyzed by the TUNEL assay and immunohistochemical staining of CD31 to quantify microvessel density (MVD). Combined treatment with TNP-470 and docetaxel synergistically inhibited PC-3 cell growth in vitro through the enhanced induction of apoptotic cell death compared with treatment with either agent alone, a result explained, at least in part, by the down-regulation as well as phosphorylation of potential anti-apoptotic genes, Bcl-2 and Bcl-XL. Combined treatment with TNP-470 and docetaxel synergistically suppressed subcutaneous PC-3 tumor growth compared with treatment with either agent alone. Furthermore, this combined regimen significantly inhibited orthotopic PC-3 tumor growth and reduced the incidence of lymph node metastasis. Immunohistochemical analysis of the subcutaneous tumor after each treatment demonstrated that administration of docetaxel as well as TNP-470 significantly induced apoptotic cell death; in contrast, a significant reduction in MVD was observed only after TNP-470. These findings suggest that docetaxel and TNP-470 act synergistically to inhibit PC-3 tumor growth and metastasis, by enhancing apoptosis and suppressing angiogenesis.     

沙利度胺联合化疗治疗骨转移去势抵抗性前列腺癌的疗效观察

背景与目的:多西他赛联合泼尼松治疗可延长转移性去势抵抗性前列腺癌患者的生存期,血管生成抑制剂也可抑制肿瘤生长,联合治疗的疗效目前仍不明确.该研究旨在观察沙利度胺联合多西他赛和泼尼松治疗骨转移的去势抵抗性前列腺癌的近期临床疗效.方法:收集2008年12月—2015年6月南京军区福州总医院收治的骨转移去势抵抗性前列腺癌患者78例,其中40例作为对照组给予多西他赛和泼尼松方案化疗,38例作为观察组在对照组的基础上给予沙利度胺联合化疗,观察两组有效率、骨痛缓解率、前列腺特异性抗原(prostate specific antigen,PSA)无进展时间、无疾病进展时间及总生存时间,并评价不良反应.结果:观察组有效率为65.79%,PSA无进展时间为4.13个月,无疾病进展时间为4.25个月,骨痛缓解率为86.84%;对照组有效率为40.00%,PSA无进展时间为3.54个月,无疾病进展时间为3.75个月,骨痛缓解率为60.00%,观察组均高于对照组,差异有统计学意义(P<0.05).治疗后两组总生存时间、患者恶心呕吐及白细胞下降等不良反应发生率比较,差异无统计学意义(P>0.05).结论:沙利度胺联合化疗治疗骨转移的去势抵抗性前列腺癌近期临床效果满意,安全,不增加不良反应,具有较高的临床应用价值.     

Targeted Antivascular Therapy with the Apolipoprotein(a) Kringle V, rhLK8, Inhibits the Growth and Metastasis of Human Prostate Cancer in an Orthotopic Nude Mouse Model

Antivascular therapy has emerged as a rational strategy to improve the treatment of androgen-independent prostate cancer owing to the necessity of establishing a vascular network for the growth and progression of the primary and metastatic tumor. We determined whether recombinant human apolipoprotein(a) kringle V, rhLK8, produces therapeutic efficacy in an orthotopic human prostate cancer animal model. Fifty thousand androgen-independent human prostate cancer cells (PC-3MM2) were injected into the prostate of nude mice. After 3 days, these mice were randomized to receive the vehicle solution (intraperitoneally [i.p.], daily), paclitaxel (8 mg/kg i.p., weekly), rhLK8 (50 mg/kg i.p., daily), or a combination of paclitaxel and rhLK8 for 4 weeks. Treatment with paclitaxel or rhLK8 alone did not show significant therapeutic effects on tumor incidence or on tumor size compared with the control group. The combination of rhLK8 and paclitaxel significantly reduced tumor size and incidence of lymph node metastasis. Significant reduction in microvessel density and cellular proliferation and induction of apoptosis of tumor cells, and tumor-associated endothelial cells, were also achieved. Similarly, PC-3MM2 tumors growing in the tibia showed significant suppression of tumor growth and lymph node metastasis by the combination treatment with rhLK8 and paclitaxel. The integrity of the bone was significantly preserved, and apoptosis of tumor cells and tumor-associated endothelial cells was increased. In conclusion, these results suggest that targeting the tumor microenvironment with the antivascular effect of rhLK8 combined with conventional cytotoxic chemotherapy could be a new and effective approach in the treatment of androgen-independent prostate cancer and their metastases.     

Overexpression of Fn14 promotes androgen-independent prostate cancer progression through MMP-9 and correlates with poor treatment outcome

Fibroblast growth factor-inducible 14 (Fn14), a transmembrane receptor binding to the multifunctional cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK), is known to modulate many cellular activities including cancer progression. Here, we demonstrated the significant role of Fn14 in invasion, migration and proliferation of androgen-independent prostate cancer (AIPC) cells. Fn14 and its ligand TWEAK were highly expressed in two AIPC cell lines, DU 145 and PC-3, whereas expression was weak in androgen-sensitive LNCaP cells. Fn14 knockdown using small-interfering RNAs attenuated migration, invasion and proliferation and enhanced apoptosis in the AIPC cell lines. Both forced overexpression of Fn14 by stable Fn14 complementary DNA transfection to PC-3 cells (PC-3/Fn14) and ligand activation by recombinant TWEAK in PC-3 cells enhanced invasion. Fn14 was shown to modulate expression of matrix metalloproteinase (MMP)-9, and MMP-9 mediated the invasive potential influenced by Fn14 in PC-3 cells. In vivo, subcutaneous xenografts of PC-3/Fn14 grew significantly faster than xenograft of PC-3/Mock, and the invasive capacity in PC-3/Fn14 was found to be higher than that of PC-3/Mock as evaluated in an invasion model of the diaphragm. Furthermore, the messenger RNA expressions of MMP-9 in PC-3/Fn14 xenografts were significantly higher than those in PC-3/Mock xenografts. Clinically, high expression of Fn14 was significantly associated with higher prostate-specific antigen recurrence rate in patients who underwent radical prostatectomy. In conclusion, the overexpression of Fn14 may contribute to multiple malignant cellular phenotypes associated with prostate cancer (PCa) progression, in part via MMP-9. TWEAK-Fn14 signaling may be a novel therapeutic target of PCa.     

Cotargeting tumor and stroma in a novel chimeric tumor model involving the growth of both human prostate cancer and bone stromal cells

Stromal-epithelial interaction contributes to local prostate tumor growth, androgen-independent progression and distant metastasis. We have established in vitro coculture and in vivo chimeric tumor models to evaluate the roles of stromal cells isolated from either osteosarcoma or normal bone, a site where prostate cancer cells frequently metastasize, in contributing to the growth and survival of human prostate cancer cells. We have evaluated extensively the effects of toxic gene therapy using luciferase-tagged chimeric human prostate cancer models both in vitro and in vivo. In the in vitro cocultured cell model, we assessed cancer cell growth and residual cellular proteins after targeting either prostate cancer epithelial cells alone or both prostate cancer and bone stromal cells. In the in vivo animal model, we measured tumor volume and serum prostate-specific antigen (PSA) in mice bearing chimeric prostate tumors comprised of human prostate tumor cells and normal bone stromal cells. Our results demonstrated that: (1) The rate of human prostate cancer cell growth in vitro is accelerated by coculturing with human and rat osteosarcoma or normal mouse bone marrow stromal cell lines. No growth stimulation was noted when cocultured with a human prostate epithelial cell line. (2) Disabling the growth of normal bone stromal cells using transgenic targeting with a bystander gene, herpes simplex virus thymidine kinase (hsv-TK), plus the pro-drug ganciclovir (GCV) or acyclovir markedly depressed the growth of cocultured human prostate cancer cells in vitro and human prostate cancer-mouse normal bone stroma chimeric tumors in vivo. (3) By cotargeting both human prostate cancer and normal mouse bone stromal cells in vitro with an adenoviral construct, Ad-hOC-TK (a replication-defective Ad5 vector with the bystander transgene hsv-TK under the control of a human osteocalcin (hOC) promoter) plus GCV4, we observed greater inhibition of tumor cell growth than by targeting a single cell compartment with Ad-PSA-TK (a vector construct similar to Ad-hOC-TK except that the transgene expression is under regulation by a full-length human PSA promoter). These results, taken together, established a basic principle that cotargeting both tumor and its supporting stroma is more efficacious than targeting a single cell compartment in the treatment of human prostate cancer bone metastasis. This principle can be applied to other clinical conditions of cancer growth where stroma contribute to the overall growth and survival potential of the cancer.     

Prostate-restricted replicative adenovirus expressing human endostatin-angiostatin fusion gene exhibiting dramatic antitumor efficacy.

PURPOSE: Our previous studies coadministering a replication-deficient adenovirus expressing endostatin and angiostatin fusion gene (EndoAngio) and a prostate-restricted, replication-competent adenovirus (PRRA) showed dramatic antitumor efficacy. This study integrated EndoAngio with an improved PRRA vector to make a single antiangiogenic PRRA, thereby exerting a similarly dramatic antitumor effect with feasibility for future clinical trials. EXPERIMENTAL DESIGN: We developed an antiangiogenic PRRA with structural improvements. The antitumor efficacy of EndoAngio-PRRA was evaluated in prostate-specific antigen/prostate-specific membrane antigen (PSA/PSMA)-positive, androgen-independent CWR22rv tumor models. The tumor vasculature and cell morphology were observed by dual-photon microscopy. The antiangiogenic effect of EndoAngio delivered by PRRA and the killing activity of EndoAngio-PRRA were evaluated in vitro. Virus-inactivated conditioned media from virus-infected PSA/PSMA-positive cells were tested for apoptosis induction in prostate cancer cells. RESULTS: Our novel EndoAngio-PRRA is a strong antiangiogenic and antitumor agent. Nine of 10 CWR22rv tumors treated by EndoAngio-PRRA completely regressed, with 1 tumor remaining in a dormant status for 26 weeks after treatment. Dual-photon microscopy revealed that EndoAngio-PRRA not only inhibited the development of tumor vasculature but also induced apoptosis in tumor cells. Subsequent in vitro study indicated that EndoAngio-PRRA exhibited stronger tumor-specific killing activity than enhanced green fluorescent protein-PRRA, which expresses enhanced green fluorescent protein instead of EndoAngio. Virus-inactivated conditioned medium from EndoAngio-PRRA-infected PSA/PSMA-positive cells induced apoptosis in C4-2 and CWR22rv cells. CONCLUSIONS: EndoAngio-PRRA uniquely combines three distinct antitumor effects to eliminate androgen-independent prostate cancer: antiangiogenesis, viral oncolysis, and apoptosis. This novel antiangiogenic PRRA represents a powerful agent feasible for future clinical trials for prostate cancer therapy.     

A case of hormone/docetaxel-refractory prostate cancer in which PSA level decreased after docetaxel+zoledronic acid treatment

The patient was a 63-year-old man who had a recurrence and bone metastasis of prostate cancer after total prostatectomy. He was diagnosed with prostate cancer refractory to hormones. Subsequently, the PSA level decreased after docetaxel therapy, but then gradually increased. Thus, he was diagnosed with bone metastasis of prostate cancer refractory to therapy with hormones or docetaxel. The PSA level decreased after the start of therapy with docetaxel+ zoledronic acid. Zoledronic acid seems to be effective not only for the prevention but also for the treatment of skeletal related events(SRE)in patients with prostate cancer with bone metastases.