Prophylactic noscapine therapy inhibits human prostate cancer progression and metastasis in a mouse model.

BACKGROUND: Noscapine has demonstrated potent antitumour activity and minimum toxicity in cancer models. Recently, noscapine has been shown to limit tumour growth and lymphatic metastasis of PC3 human prostate cancer mice. The prophylactic effects of noscapine are not known. MATERIALS AND METHODS: Nude mice received oral noscapine (300 mg/kg per day; 'treatment'; n=10) or diluent ('control'; n=10) for 56 days, beginning 7 days after inoculation with PC3 human prostate cancer cells; or noscapine for 70 days, beginning 7 days before inoculation ('pretreatment'; n=10). RESULTS: Mean total tumour volumes were 1731.6+/-602.0 mm(3) in the control group, 644.3+/-545.1 mm(3) in the noscapine pretreatment group and 910.9+/-501.1 mm(3) in the noscapine treatment group (p<0.001 pretreatment vs. control, p<0.05 pretreatment vs. control, p<0.001 pretreatment vs. treatment group), with no evidence of toxicity. Noscapine pretreatment and treatment also reduced tumour weight, the incidence of metastasis and primary tumour inhibition rate. CONCLUSION: Pretreatment with oral noscapine limited tumour growth and lymphatic metastasis of PC3 human prostate cancer in this mouse model and conferred a significant additional benefit over noscapine treatment in final tumour volume.

Noscapine inhibits human prostate cancer progression and metastasis in a mouse model.

BACKGROUND: Noscapine, a non-toxic alkaloid and common constituent of cough medicine, stabilises tubulin. It inhibits the growth of several human and murine neoplasms, with no significant toxicity. Its effect on prostate cancer has not been evaluated. MATERIALS AND METHODS: Noscapine was administered orally (300 mg/kg per day) for 56 days to PC3 human prostate cancer-bearing immunodeficient mice (n=10). Immunodeficient control mice (n=10) received only diluent in an identical regimen. RESULTS: Mean total tumour weight was 0.42 +/- 0.23 g and 0.97 +/- 0.31 g (p<0.001) in the noscapine-treated group and the control group, respectively, without evidence of toxicity. Metastases occurred less frequently in the treatment than the control group (30% vs. 90%; p<0.05). CONCLUSION: Oral administration of noscapine limited tumour growth and lymphatic metastasis of PC3 human prostate cancer in this mouse model, supporting its therapeutic potential as a nontoxic and easily administered treatment for metastatic cancer.

Monotherapy with a tumor-targeting mutant of Salmonella typhimurium cures orthotopic metastatic mouse models of human prostate cancer.

Bacterial infection occasionally has a marked therapeutic effect on malignancies, as noted as early as the 19th century. Recently, there have been attempts to develop cancer treatment by using tumor-targeting bacteria. These treatments were developed to deliver therapeutic molecules specifically to tumors. Researchers used anaerobic microorganisms that preferentially grew in necrotic tumor areas. However, the resulting tumor killing was, at best, limited. We have developed a far more effective bacterial cancer therapy by targeting viable tumor tissue by using Salmonella typhimurium leu-arg auxotrophs. Although these bacteria grow in viable as well as necrotic areas of tumors, the nutritional auxo trophy severely restricts growth in normal tissue. In the current study, we measured the antitumor efficacy of the S. typhimurium A1-R mutant, which is auxotrophic for leu-arg and has increased antitumor virulence selected by tumor passage. A1-R was used to treat metastatic PC-3 human prostate tumors that had been orthotopically implanted in nude mice. GFP was used to image tumor and metastatic growth. Of the 10 mice with the PC-3 tumors that were injected weekly with S. typhimurium A1-R, 7 were alive and well at the time the last untreated mouse died. Four A1-R-treated mice remain alive and well 6 months after implantation. Ten additional nontumor-bearing mice were injected weekly to determine the toxicity of S. typhimurium A1-R. No toxic effects were observed. The approach described here, where bacterial monotherapy effectively treats metastatic prostate tumors, is a significant improvement over previous bacterial tumor-therapy strategies that require combination with toxic chemotherapy.

The bisphosphonate olpadronate inhibits skeletal prostate cancer progression in a green fluorescent protein nude mouse model.

PURPOSE: Metastatic bone disease is one of the major causes of morbidity and mortality in prostate cancer patients. Bisphosphonates are currently used to inhibit bone resorption and reduce tumor-induced skeletal complications. More effective bisphosphonates would enhance their clinical value. EXPERIMENTAL DESIGN: We tested several bisphosphonates in a green fluorescent protein (GFP)-expressing human prostate cancer nude mouse model. The in vivo effects of four bisphosphonates, including pamidronate, etidronic acid, and olpadronate, on bone tumor burden in mice intratibially inoculated with PC-3-GFP human prostate cancer cells were visualized by whole-body fluorescence imaging and X-ray. RESULTS: The PC-3-GFP cells produced extensive bone lesions when injected into the tibia of immunocompromised mice. The skeletal progression of the PC-3-GFP cell growth was monitored by GFP fluorescence and the bone destruction was evaluated by X-ray. We showed that 3,3-dimethylaminopropane-1-hydroxy-1,1-diphosphonic acid (olpadronate) was the most effective bisphosphonate treatment in reducing tumor burden as assessed by GFP imaging and radiography. The GFP tumor area and X-ray score significantly correlated. Reduced tumor growth in the bone was accompanied by reduced serum calcium, parathyroid hormone-related protein, and osteoprotegerin. CONCLUSIONS: The serum calcium, parathyroid hormone-related protein, and osteoprotegerin levels were significantly correlated with GFP area and X-ray scores. Treatment with olpadronate reduced tumor growth in the bone measured by GFP and X-ray imaging procedures. Imaging of GFP expression enables monitoring of tumor growth in the bone and the GFP results complement the X-ray assessment of bone disease. The data in this report suggest that olpadronate has potential as an effective inhibitor of the skeletal progression of clinical prostate cancer.

Direct evidence that PTHrP expression promotes prostate cancer progression in bone.

Parathyroid hormone-related protein (PTHrP) is an oncoprotein that is expressed in many malignancies as well as normal tissues. At essentially every site of expression, PTHrP regulates cell growth and proliferation. We and other investigators have previously reported that PTHrP is widely expressed by prostate cancer. For this tumor, there are substantial in vitro and correlative data that PTHrP expression regulates the progression of the tumor, especially in bone, but little direct data. We studied the effects of PTHrP expression on prostate cancer behavior directly in a mouse model of human prostate cancer cells that were transfected to express different forms of the polypeptide and then injected intraskeletally. Skeletal progression of the prostate cancer cells was evaluated radiologically and by measurement of serum tumor markers. PTHrP transfection converted a non-invasive cell line into one that progressed in the skeleton: Injection of the PTHrP transfected cells resulted in greater tumor progression in bone when compared to non-transfected cells, and this effect was also influenced by non-amino terminal peptides of PTHrP. Serum measurements of PTHrP, IL-6, IL-8, and calcium reflected tumor burden. Our experiments provide direct in vivo evidence that PTHrP expression results in the skeletal progression of prostate cancer cells.

Real-time whole-body imaging of an orthotopic metastatic prostate cancer model expressing red fluorescent protein.

BACKGROUND: We describe here, a whole-body imageable spontaneous metastatic model of human prostate cancer developed by surgical orthotopic implantation (SOI) and visualized by red fluorescent protein (RFP) expression. METHODS: Human prostate cancer PC-3 cells were transduced with the pLNCX2-DsRed-2-RFP retroviral vector containing the RFP and neomycin-resistance genes. A stable RFP-expressing PC-3 clone was selected in 800 microg/ml G418 in vitro and injected subcutaneously in nude mice. Stable high-level expression of RFP was maintained in the subcutaneously-growing tumors. To utilize RFP expression for metastasis studies, fragments of the subcutaneously-growing tumor, which were comprised of RFP-expressing cells, were implanted by SOI in the prostate of nude mice. RESULTS: Primary tumor growth, progression, and subsequent lymphatic metastases were visualized in live, intact animals in real time by whole-body RFP fluorescence imaging. In total, 100% of the experimental animals developed lymphatic metastasis, the growth of which was monitored in real time by whole-body imaging. The aggressive lymphatic metastasis in this model reflects one of the major metastatic routes of prostate cancer in human patients. Intravital RFP imaging visualized single cancer cells in the lung and bladder. Open RFP imaging at autopsy visualized extensive primary growth and highly disseminated lymph-node metastases. CONCLUSIONS: The long-wavelength emission of RFP enabled high sensitivity and resolution of microscopic tumor growth using appropriate imaging techniques. The model should be useful for the real-time evaluation of novel therapeutics for metastatic prostate cancer.

Long-term 6-year experience with finasteride in patients with benign prostatic hyperplasia.

OBJECTIVES: To summarize the 6-year clinical trial data with finasteride. Benign prostatic hyperplasia is a chronic and progressive disease and therefore assessment of long-term safety and efficacy is important. METHODS: The North American and International Phase III Finasteride trials enrolled symptomatic men with enlarged prostate glands. The initial 1-year placebo-controlled study was followed by a 5-year open-label extension. In total, 6-year finasteride data were available in 487 patients originally randomized to finasteride, and 5-year data were available on 238 patients originally randomized to placebo. RESULTS: After 6 years of treatment with finasteride 5 mg, the mean quasi-American Urological Association Symptom Score improved by 4.0 points, the median prostate volume decreased by 24%, and the mean maximal urinary flow rate increased by 2.9 mL/s (P <0.001 for all parameters). Long-term finasteride treatment was well tolerated, with a low incidence of drug-related sexual adverse events occurring during the first year and even fewer occurrences during the 5-year open extension. CONCLUSIONS: Treatment with finasteride leads to durable improvement in urinary tract symptoms, flow rate, and prostate volume, with no increase in the prevalence of drug-related adverse events over time.

The long-term effect of specific type II 5alpha-reductase inhibition with finasteride on bone mineral density in men: results of a 4-year placebo controlled trial.

PURPOSE: We determine the effect of long-term suppression of dihydrotestosterone with finasteride, a specific type II 5alpha-reductase inhibitor, on bone mineral density. MATERIALS AND METHODS: As part of a large (3,040 cases) 4-year, double-blind, placebo controlled trial designed to assess the long-term effects of finasteride in men with benign prostatic hyperplasia, 157 men 46 to 76 years old who were randomized to receive either 5 mg. finasteride or placebo underwent dual energy x-ray absorptiometry of the lumbar spine at baseline and at years 2, 3 and 4. RESULTS: Of 117 patients who had a baseline measurement and at least 1 additional measurement during the study baseline mean plus or minus standard deviation bone mineral density values were 1.12 +/- 0.17 gm./cm.2 in the finasteride group (63) and 1.10 +/- 0.17 gm./cm.2 in the placebo group (54). After 4 years bone mineral density was not different between treatment groups (finasteride 1.14 +/- 0.17 gm./cm.2 and placebo 1.13 +/- 0.18 gm./cm.2). Similar results were obtained for the 33 finasteride and 25 placebo treated patients who completed the study with year 4 bone mineral density measurements. CONCLUSIONS: These data demonstrate that long-term inhibition of type II 5alpha-reductase with finasteride does not adversely affect bone mineral density.

The effectiveness of reducing the daily dose of finasteride in men with benign prostatic hyperplasia.

BACKGROUND: Finasteride, a 5 alpha reductase inhibitor, is an established treatment for benign prostatic hyperplasia. The recommended dosage is 5 mg a day, however case reports have show effectiveness with lower doses. The objective of the current study was to determine in men with benign prostatic hyperplasia, previously treated for at least one year with finasteride 5 mg daily, if they will maintain subjective and objective improvements in urinary obstruction when treated with 2.5 mg of finasteride daily for one year. METHODS: In an open label, prospective study, 40 men with benign prostatic hyperplasia, previously treated for at least one year with 5 mg of finasteride, took 2.5 mg of finasteride daily for one year. Measurements included AUA symptom score, maximum flow rate, voided volume and PSA. RESULTS: There were no significant changes in maximum flow rate, voided volume, or AUA symptom score after one year of finasteride 2.5 mg daily therapy. PSA increased significantly, p <.01, after one year of finasteride 2.5 mg daily, 2.0 +1.4 ng/ml, when compared to finasteride 5 mg daily, 1.4+ 1.0 ng/ml. CONCLUSIONS: The daily dose of finasteride can be reduced to 2.5 mg daily without significant effect on subjective and objective measures of urinary obstruction. Although statistically significant increases in PSA are noted when reducing the daily finasteride dose from 5 mg to 2.5 mg, the clinical significance of a mean.6 ng/ml increase in PSA is questionable.