Growth of heterotopic LNCaP prostate cancer tumor in nude mice is not affected by dietary calcium.

BACKGROUND: We attempted to provide experimental evidence linking increased dietary calcium to progression of prostate cancer, as suggested by some epidemiological studies, using a heterotopic prostate cancer nude mice model. METHODS: Twenty heterotopic LNCaP prostate cancer tumor bearing nude mice were randomly assigned to one of the four groups: (I) high fat/low calcium diet, (II) high fat and high calcium diet, (III) high fat diet fortified with Vitamin D3, and (IV) high fat and high calcium diet fortified with Vitamin D3. In addition to weekly animal weights and tumor size measurements, the serum prostate specific antigen (PSA), 25-hydroxy Vitamin D3, calcium, phosphorus, total protein, albumin (to account for bound calcium) [1], and serum alkaline phosphatase (a measure of bone loss) [2] were determined at the termination of experiments. RESULTS: Although the serum calcium and 25-hydroxy Vitamin D3 were significantly higher in groups III and IV compared to groups I and II (P < 0.05), there was no significant difference between the tumor growth rates, final tumor weights (P = 0.9), and the serum PSA levels (P = 0.94) between the four groups. CONCLUSIONS: The results suggest that dietary calcium does not significantly affect the growth of heterotopic LNCaP prostate cancer in nude mice.

Perspectives on prostate cancer diagnosis and treatment: a roundtable.

This roundtable was held September 30, 2000. It addressed, first of all, the accuracy and proper interpretation of the available prostate-specific antigen assays. Dr. Brawer presented data to demonstrate the specificity of the complexed prostate-specific antigen assay. Dr. Stamey counterpoised evidence that pretreatment prostate-specific antigen levels less than 9 ng/mL are attributable to benign prostatic hyperplasia and therefore are of little value as an indicator of when to initiate treatment for prostate cancer. The other roundtable participants offered reviews and new data regarding hormonal therapy as primary or adjunctive treatment of prostate cancer. Dr. Fowler presented a large retrospective series of men with locally advanced prostate cancer for whom androgen ablation was the primary therapy. Dr. Droller discussed his center's experience in integrating hormonal therapy with brachytherapy. Finally, Dr. Messing reviewed and critiqued the evidence that the combination of hormonal and radiation therapy improves survival.

Partial cystectomy during radical surgery for nonurological malignancy.

PURPOSE: It is not uncommon for a locally advanced, nonurological malignancy to invade the bladder. Partial cystectomy may be required to ensure complete tumor eradication. To our knowledge the true benefit of this procedure is unknown. MATERIALS AND METHODS: A total of 45 patients underwent partial cystectomy as part of radical surgery for a nonurological malignancy. We retrospectively reviewed these cases to determine which malignancies are prone to invade the bladder, the incidence of malignant invasion, the complication rate and the prognosis after wide en bloc resection. RESULTS: Colorectal adenocarcinoma accounted for the majority of cases. Tumor invaded only 11 bladder specimens (21.5%). Radical surgery was performed with curative intent in 30 patients, of whom 23 had negative surgical margins. At a mean followup of 30.7 months 16 of these 23 patients (69.6%) were free of disease or died of other disease processes. Disease progression and/or cancer related death occurred in 14 of the 15 patients (93.3%) who underwent surgery for palliation and in 16 of the 17 (94.1%) with positive margins at a mean of 21.7 months. Overall disease specific survival in those with malignant invasion was 27.3% compared to 41.2% when the bladder was fixed by a dense fibrous reaction only. No reported complications were related to partial cystectomy at followup. CONCLUSIONS: Advanced primary and recurrent nonurological malignancies often involve the bladder. Partial cystectomy may be necessary due to a dense fibrous reaction or direct tumor extension. While this distinction is made only after formal pathological results are reviewed, wide en bloc resection is necessary to ensure complete excision. When radical surgery is performed with curative intent and negative surgical margins are achieved, patients are likely to experience prolonged disease-free survival.

Dietary trial in prostate cancer: Early experience and implications for clinical trial design.

Much epidemiologic and case-controlled evidence suggests that diet may be a modifier of prostate cancer risk. However, the role of dietary modification in men known to have prostate cancer is a matter of some debate. To elucidate the effect of diet and comprehensive lifestyle changes on cancer risk, we are conducting a randomized, prospective clinical trial on men with clinically localized prostate cancer who have selected "watchful waiting" as primary therapy. Since its inception in April 1997, 93 men have been randomized to control (n = 47) or dietary and lifestyle intervention (n = 46). Patients in the intervention group are asked to eat a low-fat, soy-supplemented vegan diet and take part in stress management, psychosocial group support, and exercise programs. After 1 year, adherence to all four interventions was greater than 80%, and no deaths or adverse outcomes have occurred. To date, we have collected prostate-specific antigen and endorectal magnetic resonance imaging and spectroscopy data on 63 patients (34 control and 29 intervention). This study demonstrates that a randomized, prospective dietary trial for men with localized prostate cancer is safe and feasible. The methodologies used provide insights into practical aspects of diet design and compliance assessment that may be useful templates for future dietary trials.

Spectrum-analysis and neural networks for imaging to detect and treat prostate cancer.

Conventional B-mode ultrasound currently is the standard means of imaging the prostate for guiding prostate biopsies and planning brachytherapy to treat prostate cancer. Yet B-mode images do not adequately display cancerous lesions of the prostate. Ultrasonic tissue-type imaging based on spectrum analysis of radiofrequency (rf) echo signals has shown promise for overcoming the limitations of B-mode imaging for visualizing prostate tumors. This method of tissue-type imaging utilizes nonlinear classifiers, such as neural networks, to classify tissue based on values of spectral parameter and clinical variables. Two- and three-dimensional images based on these methods demonstrate potential for guiding prostate biopsies and targeting radiotherapy of prostate cancer. Two-dimensional images are being generated in real time in ultrasound scanners used for real-time biopsy guidance and have been incorporated into commercial dosimetry software used for brachytherapy planning. Three-dimensional renderings show promise for depicting locations and volumes of cancer foci for disease evaluation to assist staging and treatment planning, and potentially for registration or fusion with CT images for targeting external-beam radiotherapy.

Three-dimensional ultrasound analyses of the prostate.

Although conventional ultrasonography has proven to be clinically useful for depicting many types of cancerous lesions, it cannot distinguish reliably between cancerous and noncancerous tissue of the prostate. Therefore, conventional transrectal ultrasonography (TRUS) is used primarily for general evaluations of the gland and for guiding biopsies based on clearly imaged anatomic features such as the capsule, seminal vesicles, and urethra. Spectrum analysis extracts ultrasound signal parameters associated with biopsy-proven tissue types, and these parameters are then classified using neural network tools such as learning vector quantization, radial basis, and multilayer perceptron algorithms. Classification of cancerous and noncancerous prostate tissue using neural networks produces receiver operating characteristic (ROC) curves of 0.87 +/- 0.04 compared with 0.64 +/- 0.04 for conventional ultrasonography. To image the prostate using these methods, parameter values are computed at each pixel location, then translated into a score for the likelihood of cancer using a look-up table generated using the best classification algorithm. The score for cancer likelihood is expressed as a gray-scale or color value, and the resulting image may be useful to guide biopsies or therapy. Changes in parameter or score values over time potentially can be used to assess progression of disease or efficacy of therapy.

Update on Memorial Sloan-Kettering Cancer Center studies of neoadjuvant hormonal therapy for prostate cancer.

PURPOSE: We report the results of surgery in 520 patients with clinically localized carcinoma of the prostate (CaP) who received preoperative neoadjuvant hormonal therapy (NHT) for 3 to 11(+) months. METHODS: The results in the NHT patients were compared with those in 1,413 men having surgery without NHT at our institution during the same time period. In the group without pretreatment, the median and mean follow-up was 36 and 21 months, respectively. In the patients receiving NHT, the median follow-up was 33 months and the mean 41 months. RESULTS: The overall disease-free survival (DFS) rate (serum prostate specific antigen [PSA] concentration < or = 0.2 ng/mL) was 75% at 5 years and 50% at 10 years. There was no statistically significant difference in overall DFS rate between men who had NHT and those who did not. No DFS advantage could be demonstrated for those patients with a presenting PSA >20 ng/mL who received NHT compared with patients with the same PSA concentration who did not receive NHT. Despite our previous experience indicating improved survival with NHT in men with a presenting PSA of > 10 ng/mL, we could find no advantage to NHT in enhancing DFS. At a median survival of 35 months (mean 41 months) in 201 men with an initial PSA > or = 10 ng/mL, 70% had an undetectable PSA concentration at 5 years compared with 72% at the same time point in men presenting with PSA <10 ng/mL. In the group expected to have the best surgical result; i.e. those men whose preoperative PSA was < or = 7 ng/mL, there was no DFS difference in men given NHT compared with those having no hormonal manipulation. Patients presenting with stage T(1) disease had a significantly better DFS than those with either T(2) or T(3) CaP. However, within each stage, the addition of NHT to surgery did not result in a higher DFS rate. The 5- and 10-year DFS rates for stage T(1) were 80% and 64%, for T2 disease 78% and 50%, and for T3 disease 67% and 50%. There was a statistically significant difference (P < or = 0.003) in survival between stage T(1) and stage T(2) disease, but no significant difference in DFS was noted in patients presenting with stage T(2) compared with T3 cancer (P = 0.431). Gleason score was not a significant predictor of durable DFS, and the addition of NHT did not improve the DFS within groups of patients with similar Gleason scores. Men with only one or two positive biopsy cores did significantly better than those with more than three positive cores (P = 0.06). There was a significant difference in DFS between men who had organ-confined disease and those with disease outside the gland (P = 0.0003). However, NHT did not improve DFS. The presence of positive surgical margins was a negative prognostic factor (P = 0. 001). Men who received NHT had a statistically lower positive margin rate (P = 0.001), but NHT did not increase the likelihood of a durable DFS (P = 0.175). The duration of NHT did not affect the DFS (P = 0.100 for <3 v >3 months). CONCLUSION: There appears to be no subset of men undergoing radical prostatectomy in whom the routine administration of NHT is beneficial despite the statistically significant improvement in the pathologic findings.

Historical perspective on prostate brachytherapy.

Brachytherapy--radiation delivered close to or within a tumor--had its origins at the beginning of this century. Its use in prostate cancer was delayed first by the view that this was a relatively radioresistant cancer and then by clinical experience showing high failure and morbidity rates. More recently, technological innovations such as ultrasonography and computer-based treatment planning have made prostate brachytherapy a reasonable treatment option for many patients.

Radical cystectomy for invasive bladder cancer: contemporary results and remaining controversies.

The impact of stage progression of superficial cancer to invasive disease is profound. However, the optimal-timed management of invasive bladder cancer is still controversial. Pelvic lymph node dissection and radical cystectomy are considered to be the optimal therapy regarding local tumor control and ultimate cure of cancer, whereas chemotherapy offers the only viable but limited option for patients with distant metastasis or locally advanced disease. Identification of conventional and molecular prognostic factors to predict cancer-specific survival following radical cystectomy is one important step to identify candidates that may benefit from early cystectomy or adjunct chemotherapy. With this background, the results of historic and contemporary radical cystectomy series for carcinoma of the bladder are reviewed.

Effectiveness of combined interleukin 2 and B7.1 vaccination strategy is dependent on the sequence and order: a liposome-mediated gene therapy treatment for bladder cancer.

We have developed a novel liposome-mediated immunogene therapy using interleukin 2 (IL-2) and B7.1 in a murine bladder cancer model. A carcinogen-induced murine bladder cancer cell line, MBT-2, was transfected with cationic liposome 1,2-dimyristyloxypropyl-3-dimethyl-hydroxyethyl ammonium bromide/dioleolylphosphatidylethanolamine and IL-2 plasmid. The optimized transfection condition generated IL-2 levels of 245-305 ng/10(6) cells/24 h, 100-fold higher than the levels seen with retrovirus transfection. Ninety percent of the peak level of IL-2 production was maintained for up to 11 days after transfection. Animal studies were conducted in C3H/HeJ female mice with 2 x 10(4) MBT-2 cells implanted orthotopically on day 0. Multiple vaccination schedules were performed with i.p. injection of 5 x 10(6) IL-2 and/or B7.1 gene-modified cell preparations. The greatest impact on survival was observed with the day 5, 10, and 15 regimen. Control animals receiving retrovirally gene-modified MBT-2/IL-2 cell preparations had a median survival of 29 days. Animals receiving the IL-2 liposomally gene-modified cell preparation alone had a median survival of 46 days. Seventy-five percent of animals receiving IL-2 followed by B7.1 gene-modified tumor vaccines were the only group to show complete tumor-free survival at day 60. All of these surviving animals rejected the parental MBT-2 tumor rechallenge and survived at day 120 with a high CTL response. In conclusion, liposome-mediated transfection demonstrates a clear advantage as compared with the retroviral system in the MBT-2 model. Multi-agent as opposed to single-agent cytokine gene-modified tumor vaccines were beneficial. These "targeted" sequential vaccinations using IL-2 followed by B7.1 gene-modified tumor cells significantly increased a systemic immune response that translated into increased survival.

Intravesical liposome-mediated interleukin-2 gene therapy in orthotopic murine bladder cancer model.

Using a novel orthotopic MBT-2 murine bladder tumor model, we evaluated the feasibility of intravesical gene therapy utilizing a cationic liposome, DMRIE/DOPE. Superficial bladder tumors were consistently established by intravesical instillation of 5x10(5) MBT-2 cells in syngeneic C3H female mice. In situ gene transfer to bladder tumors was accomplished via intravesical instillation of plasmid DNA/DMRIE/DOPE lipoplex. Beta-Galactosidase (beta-gal) gene expression was preferentially evident in bladder tumors and was present for at least 7 days after a single 30 min in situ transfection. Murine interleukin-2 (IL-2) gene was used for treatment of 3-day-old pre-established bladder tumors. Forty percent of animals treated with IL-2 gene were completely free of tumors by 60 days following the initial tumor implantation, while all control groups treated with beta-gal gene died. Those animals initially cured of pre-established tumors were completely resistant to a subsequent tumor re-challenge and their splenocyte-derived cytotoxic T lymphocytes were shown to be specific to MBT-2 cells, indicating that immunological memory against MBT-2 tumors was elicited by the treatment. These results demonstrate the possibility of an effective clinical application of this in situ intravesical IL-2 gene delivery system to high-risk superficial bladder tumors, obviating a need for tumor procurement and ex vivo gene transfer.

Bryostatin 1 induces prolonged activation of extracellular regulated protein kinases in and apoptosis of LNCaP human prostate cancer cells overexpressing protein kinase calpha.

Previously, we reported that 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced apoptosis of LNCaP human prostate cancer cells was accompanied by prolonged translocation of protein kinase C (PKC)alpha to non-nuclear membranes and that TPA-resistant LNCaP cells had down-regulated PKCalpha. Here we show that 10 nM bryostatin 1 induced transient membrane translocation and down-regulation of PKCalpha, prolonged translocation of PKCdelta and epsilon to non-nuclear membranes, and did not induce cell death but blocked TPA-induced apoptosis. To test the hypothesis that inhibition of TPA-induced apoptosis by bryostatin 1 was due to down-regulation of PKCalpha, we inducibly overexpressed PKCalpha in LNCaP cells. Overexpression of PKCalpha alone did not induce apoptosis, even in clones that contained much more membrane-bound, active PKCalpha than was observed in TPA-treated untransfected LNCaP cells. However, the addition of 10 nM bryostatin 1 to PKCalpha-overexpressing LNCaP cells did not yield down-regulation of PKCalpha and induced extensive apoptosis. Immunoblot analysis revealed that TPA induced prolonged hyperphosphorylation of Raf-1 and activation of extracellular-regulated/mitogen-activated protein kinases 1 and 2 in untransfected LNCaP cells, as did bryostatin 1 in PKCalpha-overexpressing cells. On the other hand, bryostatin 1 induced only transient hyperphosphorylation of Raf-1 and activation of extracellular-regulated/mitogen-activated protein kinases 1 and 2 in untransfected LNCaP cells. These results confirm a role of prolonged membrane-associated PKCalpha in PKC activator-mediated LNCaP apoptosis and suggest involvement of the mitogen-activated protein kinase pathway.

Expression of c-kit and kit-ligand in benign and malignant prostatic tissues.

The tyrosine kinase receptor c-kit and its ligand [kit ligand (KL) or stem cell factor (SCF)] exert a broad range of biological activities during organogenesis and normal cell development. Recent studies have revealed that altered c-kit levels occur in a variety of malignancies and cancer cell lines. KL has also been shown to stimulate the growth of malignant cells, as well as to promote chemotaxis. We had previously reported expression of KL in stroma cells of normal human prostate. The present study was undertaken in order to analyze the patterns of expression of c-kit and KL in a well characterized set of prostatic tissues, including normal prostate (n=4), benign prostatic hyperplasia (BPH) (n=53) and adenocarcinoma (n=46) samples. The distribution of c-kit and KL proteins was studied by immunohistochemical analyses, while transcript levels were determined by in situ hybridization with specific RNA probes on a subset of the benign and malignant tissues referred above. In addition, reverse-transcriptase polymerase chain reaction (RT-PCR) was performed to determine levels of c-kit and KL expression in cultures of epithelial and stroma cells, as well as in the prostate cancer cell lines LNCaP, DU145 and PC3. c-kit protein in normal prostate was exclusively detected in mast cells by immunohistochemistry and in situ hybridization. However, c-kit transcripts, but not c-kit protein, were detected in low levels and with an heterogeneous pattern in basal epithelial cells of ducts and acini. c-kit in BPH was detected in epithelial cells in 9 of 53 (17%) specimens. c-kit protein expression in malignant epithelial cells was identified in 1 of 46 (2%) tumors. However, c-kit transcripts were detected in low levels by in situ hybridization in most of the tumors analyzed. KL protein and transcripts in normal prostate were detected in high levels in stroma cells. However, epithelial cells were unreactive for anti-KL antibody, but showed low levels of KL transcripts mainly in cells of the basal layer. Basal epithelial cells in hyperplastic glands showed KL expression in 13 of 53 (24%) specimens. KL protein in tumor cells was noted in 18 of 46 (39%) cases. c-kit transcripts were not found in normal prostate and in the 3 cancer cell lines analyzed by RT-PCR, however, it was present in cultured epithelial cells of BPH, and in cultures of stroma cells from both normal and BPH. The majority of cultured cell lines of epithelial and stromal origin displayed considerable levels of KL. In addition all prostate cell lines studied showed significant levels of KL transcripts. In summary, co-expression of c-kit and KL in a subset of BPH cases may suggest an autocrine mode of signaling. Data from this study reveals that altered patterns of c-kit and KL expression are associated with BPH and adenocarcinoma of prostate. It appears that KL induces mast cells proliferation and maturation and enhances their release of protease. This could explain the accumulation of mast cells at tumor sites, a phenomenon that was not observed in normal prostate or BPH samples.

The role of dietary manipulation in biochemical recurrence of prostate cancer after radical prostatectomy.

In 1999, we continue to be faced with difficulties in treating prostate cancer, which remains the leading cause of cancer and the second leading cause of cancer-related deaths in men. In the prostate-specific antigen (PSA) era, we must also determine which therapies, if any, are appropriate for the treatment of a biochemical or PSA relapse. In view of the limited number of efficacious and durable treatments for prostate cancer recurrence, the medical community has had to investigate nontraditional therapies. In the recent past, an expanding body of evidence has implicated certain nutrients in carcinogenesis and cancer progression. This article discusses the role of diet in prostate carcinogenesis and the rationale for dietary manipulation as a treatment strategy for the prevention of primary and secondary (recurrent) prostate cancer.

Effect of neoadjuvant hormonal therapy on prostatic intraepithelial neoplasia and its prognostic significance.

PURPOSE: We studied the effect of neoadjuvant hormonal therapy on prostatic intraepithelial neoplasia in patients undergoing radical prostatectomy and assessed the effect of prostatic intraepithelial neoplasia on disease recurrence as measured by serum prostate specific antigen (PSA). MATERIALS AND METHODS: A total of 278 patients with clinically localized prostate cancer were included in phase II and III studies evaluating radical prostatectomy alone versus radical prostatectomy following neoadjuvant hormonal therapy at Memorial Sloan-Kettering Cancer Center between October 1991 and August 1996. Patient data related to prostatic intraepithelial neoplasia were analyzed. RESULTS: Of 275 evaluable patients 145 (52.7%) had prostatic intraepithelial neoplasia. Of 50 patients treated with neoadjuvant hormonal therapy (hormone group) 22 (44%) had a lower incidence of prostatic intraepithelial neoplasia compared to 69 of 80 controls (86.3%) (chi-square test p<0.0001). Of 262 patients (95.3%) with followup PSA 44 (16.8%) had PSA recurrence at a median followup of 32 months, with a median time to recurrence of 30 months. PSA recurrence was noted in 23 of 145 patients with compared to 21 of 130 without prostatic intraepithelial neoplasia (chi-square test p = 0.95), and did not significantly differ between the hormone group (25 of 142, 17.6%) and controls (19 of 130, 14.6%) (chi-square test p = 0.45). CONCLUSIONS: While patients treated with neoadjuvant hormonal therapy had significantly lower incidence of prostatic intraepithelial neoplasia, neither prostatic intraepithelial neoplasia nor neoadjuvant hormonal therapy significantly affected PSA recurrence at a median followup of 32 months.