Matrix metalloproteinase and heparin-stimulated serine proteinase activities in post-prostate massage urine of men with prostate cancer.

Proteinases secreted by the prostate gland have a reproductive function in cleaving proteins in the ejaculate and in the female reproductive tract, but some may have a fundamental role in disease and pathological processes including cancer. The purpose of this study was to determine if there were differences in proteinase activities in urine samples collected following prostate massage of men positive (CaP) or negative (no evidence of malignancy, NEM) for biopsy determined prostate cancer. Matrix metalloproteinase (MMP) and serine proteinase activities were detected using protein substrate zymography. There were no differences in activities of MMP-2, proMMP-9, and MMP-9/NGAL (neutrophil gelatinase associated lipocalin) complex (gelatin substrate) in men with detected prostate cancer, although the latter two were somewhat diminished. A caseinolytic activity of about 75kDa inhibited by calcium did not differ between the NEM and CaP groups. Heparin stimulated calcium sensitive gelatinolytic activities of approximately 22, 42, and 60kDa, but did not affect activities of MMP-2, MMP-9, or the 75kDa caseinolytic activity. The 22, 42, and 60kDa activities appear to be serine proteinases since they were inhibited by benzamidine. There was a significant decrease in the 22kDa heparin-stimulated serine proteinase activity in urines of men with cancer. Proteinase expression and activities, perhaps in combination with other potential markers, may prove useful in urine for detection and evaluation of prostate cancer.

Alvimopan, a peripherally acting µ-opioid receptor antagonist, is associated with reduced costs after radical cystectomy: economic analysis of a phase 4 randomized, controlled trial.

PURPOSE: We evaluated the effect of alvimopan treatment vs placebo on health care utilization and costs related to gastrointestinal recovery in patients treated with radical cystectomy in a randomized, phase 4 clinical trial. MATERIALS AND METHODS: Resource utilization data were prospectively collected and evaluated by cost consequence analysis. Hospital costs were estimated from 2012 Medicare reimbursement rates and medication wholesale acquisition costs. Differences in base case mean costs between the study cohorts for total postoperative ileus related costs (hospital days, study drug, nasogastric tubes, postoperative ileus related concomitant medication and postoperative ileus related readmissions) and total combined costs (postoperative ileus related, laboratory, electrocardiograms, nonpostoperative ileus related concomitant medication and nonpostoperative ileus related readmission) were evaluated by probabilistic sensitivity analysis using a bootstrap approach. RESULTS: Mean hospital stay was 2.63 days shorter for alvimopan than placebo (mean±SD 8.44±3.05 vs 11.07±8.23 days, p=0.005). Use of medications or interventions likely intended to diagnose or manage postoperative ileus was lower for alvimopan than for placebo, eg total parenteral nutrition 10% vs 25% (p=0.001). Postoperative ileus related health care costs were $2,340 lower for alvimopan and mean total combined costs were decreased by $2,640 per patient for alvimopan vs placebo. Analysis using a 10,000-iteration bootstrap approach showed that the mean difference in postoperative ileus related costs (p=0.04) but not total combined costs (p=0.068) was significantly lower for alvimopan than for placebo. CONCLUSIONS: In patients treated with radical cystectomy alvimopan decreased hospitalization cost by reducing the health care services associated with postoperative ileus and decreasing the hospital stay.

Systemic administration of antisense oligonucleotides simultaneously targeting CK2α and α' subunits reduces orthotopic xenograft prostate tumors in mice.

CK2 is a highly conserved, ubiquitous, signal responsive protein serine/threonine kinase. CK2 promotes cell proliferation and suppresses apoptosis, and increased CK2 expression is observed in all cancers examined. We previously reported that direct injection of antisense (AS) CK2α phosphorothioate oligonucleotides (PTO) into xenograft prostate tumors in mice significantly reduced tumor size. Downregulation of CK2α in tumor cells in vivo appeared to result in overexpression of CK2α' protein. This suggested that in cancer cells downregulation of CK2α might be compensated by CK2α' in vivo, prompting us to design a bispecific (bs) AS PTO (bs-AS-CK2) targeting both catalytic subunits. bs-AS-CK2 reduced CK2α and α' protein expression, decreased cell proliferation, and induced apoptosis in cultured cells. Biodistribution studies of administered bs-AS-CK2 oligonucleotide demonstrated its presence in orthotopic prostate xenograft tumors. High dose injections of bs-AS-CK2 resulted in no damage to normal liver or prostate, but induced extensive cell death in tumor tissue. Intraperitoneal treatment with bs-AS-CK2 PTO decreased orthotopic tumor size and downregulated both CK2 mRNA and protein expression. Tumor reduction was accomplished using remarkably low doses and was improved by dividing the dose using a multi-day schedule. Decreased expression of the key signaling pathway proteins NF-κB p65 and AKT was also observed. We propose that the molecular downregulation of CK2 through bispecific targeting of the two catalytic subunits may be uniquely useful for therapeutic elimination of tumors.

Association between lymph node density and disease specific survival in patients with penile cancer.

PURPOSE: We assessed the value of lymph node density for predicting disease specific survival after lymphadenectomy for penile cancer. MATERIALS AND METHODS: Data were collected retrospectively in 75 and prospectively in 88 consecutive patients with squamous cell carcinoma of the penis treated at M. D. Anderson Cancer Center between 1979 and 2007. We identified 45 patients with penile cancer and nodal metastasis who underwent lymphadenectomy with curative intent. Lymph node density was analyzed as a categorical variable by grouping patients into 2 or 3 categories based on equal percents. We explored the prognostic value of lymph node density for predicting disease specific survival in this cohort. RESULTS: Median followup was 23.7 months in all patients. By the time of analysis 22 patients had died, including 18 (82%) of penile cancer and 4 (18%) of other causes. Median lymph node density in patients alive or dead of other causes was 3.4% (IQR 2.9-5.9) compared to 43.3% (IQR 15.6-80) in those dead of disease (p <0.001). Median lymph node density in all patients was 6.7%. Estimated 5-year disease specific survival in patients with lymph node density 6.7% or less was significantly better than that in patients with lymph node density greater than 6.7% (91.2%, 95% CI 53.9-98.8 vs 23.3%, 95% CI 7.0-45.1, p <0.001). In models comparing lymph node density to known prognostic features lymph node density remained statistically significant, while the other factors were no longer statistically associated with disease specific survival. CONCLUSIONS: Lymph node density proved to be a significantly better prognosticator of disease specific survival than the current TNM nodal staging system in patients with penile cancer and nodal involvement. Further independent validation is required to determine the clinical usefulness of lymph node density in this patient population.

Repeated intravesical instillations of an adenoviral vector in patients with locally advanced bladder cancer: a phase I study of p53 gene therapy.

PURPOSE: We investigated the feasibility, safety, and biologic activity of adenovirus-mediated p53 gene transfer in patients with locally advanced bladder cancer. PATIENTS AND METHODS: Patients with measurable, locally advanced transitional-cell carcinoma of the bladder who were not candidates for cystectomy were eligible. On a 28-day cycle, intravesical instillations of INGN 201 (Ad5CMV-p53) were administered on days 1 and 4 at three dose levels (10(10) particles to 10(12) particles) or on either 4 or 8 consecutive days at a single dose level (10(12) particles). RESULTS: Thirteen patients received a total of 22 courses without dose-limiting toxicity. Specific transgene expression was detected by reverse transcriptase polymerase chain reaction in bladder biopsy tissue from two of seven assessable patients. There were no changes in p53, p21waf1/cip1, or bax protein levels in bladder epithelium evident from immunohistochemical analysis of 11 assessable patients. Outpatient administration of multiple courses was feasible and well tolerated. A patient with advanced superficial bladder cancer showed evidence of tumor response. CONCLUSION: Intravesical instillation of Ad5CMV-p53 is safe, feasible, and biologically active when administered in multiple doses to patients with bladder cancer. Observations from this study indicate that this treatment has an antitumor effect in superficial transitional-cell carcinoma. Improvements in the efficiency of gene transfer and the levels of gene expression are required to develop more effective gene therapy for bladder cancer.

Induction of apoptosis by antisense CK2 in human prostate cancer xenograft model.

Protein serine/threonine kinase CK2 (formerly casein kinase 2) is a ubiquitous protein kinase that plays key roles in cell growth, proliferation, and survival. We have shown previously that its molecular down-regulation induces apoptosis in cancer cells in culture. Here, we have employed a xenograft model of prostate cancer to extend these studies to determine whether antisense CK2alpha evokes a similar response in vivo. A single dose of antisense CK2alpha oligodeoxynucleotide given directly into the PC3-LN4 xenograft tumor in nude mouse induced a dose- and time-dependent tumor cell death in vivo. The tumor was completely resolved at the higher tested dose of the antisense. Cell death was due to apoptosis and correlated with a potent down-regulation of the CK2alpha message and loss of CK2 from the nuclear matrix in the xenograft tissue as well as in cancer cells in culture. These observations accorded with several of the earlier studies indicating that loss of CK2 from the nuclear matrix is associated with induction of apoptosis. Comparison of the effects of antisense CK2alpha oligodeoxynucleotide on cancer versus normal or noncancer cells showed that the concentration of antisense CK2alpha that elicited extensive apoptosis in tumor cells in culture or xenograft tumors in vivo had a relatively small or minimal effect on noncancer cells in culture or on normal prostate gland subjected to orthotopic injection of antisense oligodeoxynucleotide in vivo. The basis for the difference in sensitivity of cancer versus noncancer cells to antisense CK2alpha is unknown at this time; however, this differential response under similar conditions of treatment may be significant in considering the potential feasibility of targeting the CK2 signal for induction of apoptosis in cancer cells in vivo. Although much further work will be needed to establish the feasibility of targeting CK2 for cancer therapy, to our knowledge, this is the first report to provide important new evidence as an initial "proof of principle" for the potential application of antisense CK2alpha in cancer therapy, paving the way for future detailed studies of approaches to targeting CK2 in vivo to induce cancer cell death.

The prognostic value of angiogenesis and metastasis-related genes for progression of transitional cell carcinoma of the renal pelvis and ureter.

PURPOSE: We reported previously that angiogenesis evaluated by intratumor microvessel density (MVD), expression of such angiogenic factors as vascular endothelial cell growth factor (VEGF) and basic fibroblast growth factor (bFGF), and the matrix metalloproteinase-9:E-cadherin ratio (M:E ratio) could identify patients with advanced transitional cell carcinoma (TCC) of the bladder for whom chemotherapy and cystectomy will be unsuccessful. In the present study, we evaluated the significance of the M:E ratio as a predictor for prognosis for patients with TCC in the upper urinary tract (TCC-UUT). EXPERIMENTAL DESIGN: We evaluated MVD by immunohistochemistry and the expression of angiogenic and metastasis-related factors by in situ hybridization in 55 nephroureterectomy specimens from patients who received no neoadjuvant therapy. The expression of angiogenesis, angiogenic and metastasis-related factors, and clinicopathological characteristics were evaluated for their correlation with metastasis, recurrence, and disease prognosis. RESULTS: We found that tumor grade and pathological stage were important predictors for metastasis and survival in these patients. The expression level of matrix metalloproteinase type 9 (MMP-9) and type 2 (MMP-2) and the M:E ratio correlated with MVD. Increased MVD, elevated expression levels of MMP-9 and MMP-2, and a higher M:E ratio were associated with poor prognosis. Moreover, lower expression levels of E-cadherin were associated with fewer recurrences in the urinary bladder. Multivariate analysis indicated that the M:E ratio and E-cadherin expression were independent prognostic factors for disease progression and intravesical recurrence, respectively. CONCLUSION: We suggest that the M:E ratio and E-cadherin expression may be targets for novel therapeutic strategies.

Inhibition of tumorigenicity and metastasis of human bladder cancer growing in athymic mice by interferon-beta gene therapy results partially from various antiangiogenic effects including endothelial cell apoptosis.

We determined whether the IFN-beta gene could suppress angiogenesis, tumor growth, and metastasis of human bladder transitional cell carcinoma. The highly tumorigenic and metastatic 253J B-V(R) human bladder transitional cell carcinoma (TCC) cell line (resistant to the antiproliferative effects of IFN-beta) was infected in vitro with adenoviral beta-galactosidase (Ad-LacZ), murine adenoviral IFN-beta (Ad-mIFN-beta), or human adenoviral IFN-beta (Ad-hIFN-beta) and implanted into the bladders of athymic nude mice. Ad-mIFN-beta and Ad-hIFN-beta were used because of the species specificity of IFN-beta. The transient production of mIFN-beta and hIFN-beta from the infected 253JB-V(R) tumor cells significantly inhibited tumorigenicity and spontaneous lymph node metastasis. Subsequently, the 253J B-V(R) cells were implanted into the subcutis of athymic nude mice, and established tumors were treated by direct intratumoral injection with Ad-mIFN-beta, Ad-hIFN-beta, Ad-LacZ, or PBS. By in situ hybridization (ISH) and immunohistochemical analysis (IHC), expression of hIFN-beta and mIFN-beta mRNA and protein within the tumors was demonstrated after Ad-hIFN-beta and Ad-mIFN-beta gene therapy, respectively. The therapy also induced necrosis in both the Ad-mIFN-beta- and Ad-hIFN-beta-treated tumors. IHC revealed decreased tumor cell proliferation and the sequestration of activated macrophages within the tumors after Ad-mIFN-beta therapy. In addition, the expression of the proangiogenic factors bFGF, and MMP-9 protein (by IHC) was significantly down-regulated by Ad-hIFN-beta gene therapy. Double-immunofluorescent IHC for terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) and CD-31 demonstrated tumor and endothelial cell apoptosis in those tumors treated with Ad-hIFN-beta gene therapy. Tumor-induced angiogenesis, as determined by the microvessel density, was decreased in tumors treated with both Ad-mIFN-beta and Ad-hIFN-beta. These data suggest that the inhibition of tumorigenicity and the metastasis of the 253J B-V(R) cells after infection with Ad-IFN-beta is caused by the inhibition of angiogenesis and the activation of host effector cells.

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.

Surgical management of renal cell carcinoma associated with complex inferior vena caval thrombi.

The operative morbidity and mortality of radical nephrectomy are considerably higher when the vena cava is involved by the tumor. The prognostic significance of vena caval extension in this setting remains controversial. We reviewed our experience of vena caval thrombectomy specifically addressing prognostic factors. We retrospectively studied 96 patients treated at our institution between 1985 and 2001. The study population included 28 women and 68 men; (37 left- and 59 right-sided tumors). Twenty-seven patients had metastatic disease at presentation. Prognostic features (age, sex, race, side of tumor, embolization, tumor grade, tumor confinement by renal capsule, cephalic extent of thrombus, nodal status, and presence of distant metastasis) were evaluated using a Cox proportional hazards model (univariate and multivariate). These prognostic features were analyzed in the group as a whole and in the subgroup of patients who did not have metastatic disease at presentation and did not die perioperatively. There were 5 perioperative deaths. Extracapsular tumor extension and regional node involvement were present in 64% and 17% of the patients, respectively. Level of tumor thrombus were as follows: level I (41%), II (29%), III (7%), IV (15%). Fuhrman's grade was 2 in 17%, 3 in 45%, and 4 in 30% of the patients. For all 96 patients, median overall survival (OS) was 35 months. Five-year OS was 35%. The presence of distant metastasis at presentation did not significantly alter median OS (20 months with metastasis vs. 38 months without, P = 0.3), although this finding may have been confounded by selection. The presence of nodal metastasis was associated with decreased OS by multivariate analysis (P < 0.01). After exclusion of patients dying perioperatively and patients with metastasis at presentation, median OS and progression-free survival were 40 and 18 months, respectively (5-year OS was 40%). In the multivariate model, none of the factors examined were associated with OS, but age <58 years, and the presence of extracapsular tumor extension were associated with an increased risk of recurrence. In patients with renal tumors and extension of tumor thrombus into the vena cava, the level of propagation of the thrombus does not predict for OS. Selected patients with metastatic renal cancer may benefit from aggressive surgical resection of the primary tumor and associated tumor thrombus.

Tenfibgen ligand nanoencapsulation delivers bi-functional anti-CK2 RNAi oligomer to key sites for prostate cancer targeting using human xenograft tumors in mice.

Protected and specific delivery of nucleic acids to malignant cells remains a highly desirable approach for cancer therapy. Here we present data on the physical and chemical characteristics, mechanism of action, and pilot therapeutic efficacy of a tenfibgen (TBG)-shell nanocapsule technology for tumor-directed delivery of single stranded DNA/RNA chimeric oligomers targeting CK2αα' to xenograft tumors in mice. The sub-50 nm size TBG nanocapsule (s50-TBG) is a slightly negatively charged, uniform particle of 15 - 20 nm size which confers protection to the nucleic acid cargo. The DNA/RNA chimeric oligomer (RNAi-CK2) functions to decrease CK2αα' expression levels via both siRNA and antisense mechanisms. Systemic delivery of s50-TBG-RNAi-CK2 specifically targets malignant cells, including tumor cells in bone, and at low doses reduces size and CK2-related signals in orthotopic primary and metastatic xenograft prostate cancer tumors. In conclusion, the s50-TBG nanoencapsulation technology together with the chimeric oligomer targeting CK2αα' offer significant promise for systemic treatment of prostate malignancy.

Alvimopan accelerates gastrointestinal recovery after radical cystectomy: a multicenter randomized placebo-controlled trial.

BACKGROUND: Radical cystectomy (RC) for bladder cancer is frequently associated with delayed gastrointestinal (GI) recovery that prolongs hospital length of stay (LOS). OBJECTIVE: To assess the efficacy of alvimopan to accelerate GI recovery after RC. DESIGN, SETTING, AND PARTICIPANTS: We conducted a randomized double-blind placebo-controlled trial in patients undergoing RC and receiving postoperative intravenous patient-controlled opioid analgesics. INTERVENTION: Oral alvimopan 12 mg (maximum: 15 inpatient doses) versus placebo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The two-component primary end point was time to upper (first tolerance of solid food) and lower (first bowel movement) GI recovery (GI-2). Time to discharge order written, postoperative LOS, postoperative ileus (POI)-related morbidity, opioid consumption, and adverse events (AEs) were evaluated. An independent adjudication of cardiovascular AEs was performed. RESULTS AND LIMITATIONS: Patients were randomized to alvimopan (n=143) or placebo (n=137); 277 patients were included in the modified intention-to-treat population. The alvimopan cohort experienced quicker GI-2 recovery (5.5 vs 6.8 d; hazard ratio: 1.8; p<0.0001), shorter mean LOS (7.4 vs 10.1 d; p=0.0051), and fewer episodes of POI-related morbidity (8.4% vs 29.1%; p<0.001). The incidence of opioid consumption and AEs or serious AEs (SAEs) was comparable except for POI, which was lower in the alvimopan group (AEs: 7% vs 26%; SAEs: 5% vs 20%, respectively). Cardiovascular AEs occurred in 8.4% (alvimopan) and 15.3% (placebo) of patients (p=0.09). Generalizability may be limited due to the exclusion of epidural analgesia and the inclusion of mostly high-volume centers utilizing open laparotomy. CONCLUSIONS: Alvimopan is a useful addition to a standardized care pathway in patients undergoing RC by accelerating GI recovery and shortening LOS, with a safety profile similar to placebo. PATIENT SUMMARY: This study examined the effects of alvimopan on bowel recovery in patients undergoing radical cystectomy for bladder cancer. Patients receiving alvimopan experienced quicker bowel recovery and had a shorter hospital stay compared with those who received placebo, with comparable safety. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00708201.

Polysaccharide-K augments docetaxel-induced tumor suppression and antitumor immune response in an immunocompetent murine model of human prostate cancer.

Advanced castration-resistant prostate cancer has high mortality rates and limited treatment options. Novel therapies are needed to better contend with this disease. Polysaccharide-K® (PSK), an extract of the mushroom Trametes versicolor, has immunomodulatory and tumor suppressive activities. PSK is used in Asia as a cancer immunotherapy. However, its benefit in combination with taxanes for prostate cancer is unknown. We examined whether PSK would enhance docetaxel-induced apoptosis and augment anti-tumor immune responses in orthotopic tumors using transgenic adenocarcinoma of the mouse prostate (TRAMP)-C2-bearing mice. Combining PSK with docetaxel induced significantly higher tumor suppression than either treatment alone (p<0.05), including a reduction in tumor proliferation and enhanced apoptosis. Combined PSK and docetaxel treatment led to a lower decrease in number of white blood cells than docetaxel alone, an effect accompanied by increased numbers of tumor-infiltrating CD4+ and CD8+ T cells. PSK with or without docetaxel significantly enhanced mRNA expression of IFN-γ compared to control, but did not significantly alter T-regulatory FoxP3 mRNA expression in tumors. PSK also augmented docetaxel-induced splenic natural killer cell cytolytic activity against YAC-1 target cells (p=0.045). This study is the first to show that PSK enhances docetaxel-induced prostate cancer tumor suppression, apoptosis and antitumor responses.

Role for toll-like receptor 4 in TNF-alpha secretion by murine macrophages in response to polysaccharide Krestin, a Trametes versicolor mushroom extract.

Woody fungi and yeast preparations show promise in cancer treatment by activating anti-tumor immune responses. Macrophages (J774A.1) were treated with PSK, Reishi extract, scleroglucan or vehicle control. Pre-incubation with TLR4 blocking antibody inhibited TNF-alpha secretion by both J774A.1 cells and primary splenocytes but had inconclusive effect on scleroglucan-induced secretion of TNF-alpha. PSK induced TNF-alpha and IL-6 secretion by wild type but not by TLR4-deficient peritoneal macrophages. We conclude that constituents from PSK act as ligands for TLR4 receptors leading to induction of TNF-alpha and IL-6 inflammatory cytokines. Receptor-mediated differences may be due to structural differences in beta glucans or non-glucan constituents.

Increased aggressiveness of human prostate PC-3 tumor cells expressing cell surface localized membrane type-1 matrix metalloproteinase (MT1-MMP).

Membrane type-1 matrix metalloproteinase (MT1-MMP) is a multidomain transmembrane endopeptidase with a major role in physiological and pathological processes through proteolysis of extracellular matrix and other pericellular proteins. We examined cell surface function of MT1-MMP in PC-3 human prostate tumor cells selected for metastasis in nude mice (PC-3-LN4), or transfected with the full-length wild-type (WT) MT1-MMP or with the mutant form lacking the cytoplasmic tail (Delta C-MT1-MMP). Enhanced cell surface MT1-MMP was determined by fluorescence-activated cell sorting analysis and evidenced mechanistically by increased activation of proMMP-2 and invasion into type-I collagen gels. PC-3 cells overexpressing MT1-MMP grew faster than mock-transfected control cells subcutaneously in nude mice. MT1-MMP localized in caveolae, as judged by immunofluorescence microscopy and sucrose-gradient, detergent-resistant cell fractionation. Delta C-MT1-MMP was strongly associated with caveolae, whereas the WT form was present in both caveolae and noncaveolae fractions. The role of plasma membrane MT1-MMP was supported by localization of MT1-MMP by immunofluorescence microscopy at the cell surface of tumor cells in primary prostate cancers. Increased plasma membrane localization of MT1-MMP, either in caveolae or in other lipid raft structures, is a mechanism to localize this proteinase in contact with extracellular matrix and other pericellular proteins, the cleavage of which can facilitate prostate cancer cell invasion and metastasis.

WL-276, an antagonist against Bcl-2 proteins, overcomes drug resistance and suppresses prostate tumor growth.

Patients with hormone-refractory prostate cancer (HRPC) have an estimated median survival of only 10 months because of acquired drug resistance, urging the need to develop therapies against the drug-resistant HRPC phenotype. Accumulating evidence suggests that overexpressing antiapoptotic Bcl-2 family proteins is at least partially responsible for the development of drug resistance among HRPC patients. Antagonizing the antiapoptotic Bcl-2 family proteins, therefore, is one potential approach to circumventing drug resistance in HRPC. WL-276 was developed as a small-molecule antagonist against antiapoptotic Bcl-2 family proteins, with binding potency comparable to (-)-gossypol. Overexpressing Bcl-2 or Bcl-X(L) failed to confer resistance to WL-276. WL-276 also effectively induced apoptosis in PC-3 cells. In addition, three PC-3 cell lines with acquired drug resistance against standard cancer chemotherapies were more sensitive to WL-276 than the parent PC-3 cell line. The increased cytotoxicity toward drug-resistant PC-3 cells shows the clinical potential of WL-276 against HRPC that is resistant to conventional therapies. The anticancer activity of WL-276 was manifested in its suppression of PC-3-induced prostate tumor growth in vivo. The selective toxicity of WL-276 against drug-resistant PC-3 cells and its in vivo suppression of PC-3 prostate tumor growth suggest that WL-276 is a promising lead candidate for the development of Bcl-2 antagonists against drug-resistant HRPC.

Effects of soy protein isolate consumption on prostate cancer biomarkers in men with HGPIN, ASAP, and low-grade prostate cancer.

Fifty-eight men at high risk of prostate cancer or with low-grade prostate cancer were randomly assigned to consume 1 of 3 protein isolates containing 40 g protein: 1) soy protein (SPI+, 107 mg isoflavones/d); 2) alcohol-washed soy protein (SPI-, <6 mg isoflavones/d); or 3) milk protein (MPI). Proliferating cell nuclear antigen (PCNA), epidermal growth factor receptor, B-cell non-Hodgkin lymphoma-2 (Bcl-2), and Bcl-2-associated X protein (Bax) were assessed in baseline and ending prostate biopsy cores. Serum collected at 0, 3, and 6 mo was analyzed for total and free prostate specific antigen (PSA). Consumption of SPI+ did not alter any of the prostate cancer tumor markers. Bax expression decreased from baseline in the SPI- group, resulting in lower Bax expression than the MPI group. PCNA expression also decreased from baseline in the SPI- group, but this was not different from the other 2 groups. PSA did not differ among the groups at 3 or 6 mo. Interestingly, a lower rate of prostate cancer developed in the soy groups compared to the milk group (P = 0.01). These data suggest that 6-mo SPI+ consumption does not alter prostate tissue biomarkers, SPI- consumption exerts mixed effects, and less prostate cancer is detected after 6 mo of soy consumption regardless of isoflavone content.

Soy protein isolate increases urinary estrogens and the ratio of 2:16alpha-hydroxyestrone in men at high risk of prostate cancer.

Specific estrogen metabolites may initiate and promote hormone-related cancers. In epidemiological studies, significantly lower excretion of urinary estradiol (E2) and lower ratio of urinary 2-hydroxy estrogens to 16alpha-hydroxyestrone (2:16 OH-E1) have been reported in prostate cancer cases compared to controls. Although soy supplementation has been shown to increase the ratio 2:16 OH-E1 in women, no studies to our knowledge have investigated the effects of soy supplementation on estrogen metabolism in men. The objective of this randomized controlled trial was to determine the effects of soy protein isolate consumption on estrogen metabolism in men at high risk for developing advanced prostate cancer. Fifty-eight men supplemented their habitual diets with 1 of 3 protein isolates: 1) isoflavone-rich soy protein isolate (SPI+) (107 mg isoflavones/d); 2) alcohol-washed soy protein isolate (SPI-) (<6 mg isoflavones/d); or 3) milk protein isolate (MPI), each providing 40 g protein/d. At 0, 3, and 6 mo of supplementation, the urinary estrogen metabolite profile was measured by GC-MS. Both soy groups had higher E2 excretion than the MPI group at 3 and 6 mo. After 6 mo of supplementation, the SPI+ group had a significantly higher urinary 2:16 OH-E1 ratio than the MPI group. Increased urinary E2 excretion and 2:16 OH-E1 ratio in men consuming soy protein isolate are consistent with studies in postmenopausal women and suggest that soy consumption may be beneficial in men at high risk of progressing to advanced prostate cancer as a result of effects on endogenous estrogen metabolism.

Isoflavone-rich soy protein isolate suppresses androgen receptor expression without altering estrogen receptor-beta expression or serum hormonal profiles in men at high risk of prostate cancer.

The purpose of this study was to determine the effects of soy protein isolate consumption on circulating hormone profiles and hormone receptor expression patterns in men at high risk for developing advanced prostate cancer. Fifty-eight men were randomly assigned to consume 1 of 3 protein isolates containing 40 g/d protein: 1) soy protein isolate (SPI+) (107 mg/d isoflavones); 2) alcohol-washed soy protein isolate (SPI-) (<6 mg/d isoflavones); or 3) milk protein isolate (0 mg/d isoflavones). For 6 mo, the men consumed the protein isolates in divided doses twice daily as a partial meal replacement. Serum samples collected at 0, 3, and 6 mo were analyzed for circulating estradiol, estrone, sex hormone-binding globulin, androstenedione, androstanediol glucuronide, dehydroepiandrosterone sulfate, dihydrotestosterone, testosterone, and free testosterone concentrations by RIA. Prostate biopsy samples obtained pre- and postintervention were analyzed for androgen receptor (AR) and estrogen receptor-beta expression by immunohistochemistry. At 6 mo, consumption of SPI+ significantly suppressed AR expression but did not alter estrogen receptor-beta expression or circulating hormones. Consumption of SPI- significantly increased estradiol and androstenedione concentrations, and tended to suppress AR expression (P = 0.09). Although the effects of SPI- consumption on estradiol and androstenedione are difficult to interpret and the clinical relevance is uncertain, these data show that AR expression in the prostate is suppressed by soy protein isolate consumption, which may be beneficial in preventing prostate cancer.