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Biomedical subjects

D Kadmon

Publications and source records attributed to D Kadmon.

At least 37 records · Page 2Linked to original sources
PubMed2000

Suicide gene therapy toxicity after multiple and repeat injections in patients with localized prostate cancer.

PURPOSE: We assess risks, toxicity and side effects of multiple and repeat in situ suicide gene therapy in patients with localized prostate cancer. MATERIALS AND METHODS: The study population comprised patients with localized prostate cancer receiving multiple and/or repeat intraprostatic injections of a replication deficient adenovirus containing the herpes simplex virus thymidine kinase (HSV-tk) gene. Intravenous ganciclovir or oral valaciclovir was given for 14 days after injection. Patients were recruited from 4 different clinical protocols in studies of toxicity and efficacy of suicide gene therapy, and closely monitored for toxicity and side effects during and after treatment. Toxicity was graded according to the Cancer Therapy Evaluation Program common toxicity criteria published by the National Cancer Institute. RESULTS: A total of 52 patients were treated under these clinical protocols with a total of 76 gene therapy cycles. Toxic events were recorded in 16 of 29 patients (55.2%) who were given multiple viral injections into the prostate, 7 of 20 (35%) who received 2 cycles of "suicide" gene therapy and 3 of 4 (75%) who received a third course of gene therapy. All toxic events after multiple or repeat injections were mild (grades 1 to 2) and resolved completely once the therapy course was terminated. No additive toxicity was noted in patients receiving repeat gene therapy cycles. Mean followup was 12.8 months (range 3 to 34). Preliminary results for 28 patients in 2 clinical protocols indicated a mean decrease of 44% in PSA in 43%. CONCLUSIONS: Direct injection into the prostate of a replication defective adenovirus containing the HSV-tk gene followed by intravenous ganciclovir is safe even in repeat cycles.

Acyclovir↗
PubMed2000

Effect of 13-cis-retinoic acid on serum prostate-specific antigen levels in patients with recurrent prostate cancer after radical prostatectomy.

The objective of this study was to determine whether there is any beneficial effect of oral 13-cis-retinoic acid (isotretinoin) on prostate cancer, using serum prostate-specific antigen (PSA) levels as a surrogate end point in patients with a rising serum PSA after radical prostatectomy. In the first phase, the effect of the drug on the serum PSA level was tested in 14 control patients with normal prostates. Our goal was to exclude any effect of isotretinoin on PSA secretion and metabolism and thus to validate any observed effect on PSA as indicative of anticancer activity. In the second phase, patients with rising PSA levels after radical prostatectomy and no evidence of metastatic disease were treated with oral isotretinoin at a daily dose of 1.0 mg/kg. Serum PSA levels were checked monthly for the first 4 months after initiation of treatment and every 3 months thereafter. No significant changes in serum PSA levels after 3 months of isotretinoin treatment were recorded in the control group (P = 1.000). Three of 11 postprostatectomy patients (27%) had a PSA reduction of 28%, 15%, and 6.6% after initiation of treatment that lasted for a period of 2-3 months. In two of these three patients, the PSA levels subsequently rose exponentially. Another patient displayed a stabilization of the serum PSA curve for 3 months after an initial sharp rise. No grade 3 or 4 toxicity was recorded in this group of patients. Isotretinoin had a modest, transient effect on the serum PSA level in 4 of 11 (36%) patients with a rising serum PSA after radical prostatectomy. We conclude that this drug is unlikely to be of major therapeutic benefit in prostate cancer patients when used as a single agent. However, its modest effect argues for the exploration of other, more potent retinoids for prostate cancer therapy.

Adult↗
PubMed1998

A c-rasHa mutation in the metastasis of a human papillomavirus (HPV)-18 positive penile squamous cell carcinoma suggests a cooperative effect between HPV-18 and c-rasHa activation in malignant progression.

BACKGROUND: Human papillomaviruses (HPV) have been implicated in the etiology of anogenital squamous epithelial tumors. Of the 65 HPV strains, subtypes HPV-16 and HPV-18 frequently are associated with malignant conditions and are capable of transforming keratinocytes in vitro. However, additional cellular changes are necessary to confer tumorigenicity to HPV-infected cells. Secondary events implicated in the progression to malignancy include loss of tumor suppressor genes such as p53 and/or activation of cellular oncogenes such as c-rasHa. METHODS: Polymerase chain reaction (PCR) was used to identify HPV-16 or HPV-18 genetic sequence in primary penile squamous cell carcinoma and two inguinal lymph node metastases. p53 and c-rasHa loci were analyzed by sequencing of PCR-amplified genomic DNA. RESULTS: HPV-18 but not HPV-16 infection was found in the primary carcinoma and in inguinal metastases occurring 5 and 7 years after the initial lesion. Sequence analysis did not identify any p53 mutations in the primary carcinoma or its metastases. However, although the primary lesion and the 5-year metastasis encoded wild-type c-rasHa, the 7-year metastasis had a missense mutation within c-rasHa codon 61. CONCLUSIONS: To the authors' knowledge, this is the first report of an activating c-rasHa mutation associated with squamous cell carcinoma of the penis. The presence of activated c-rasHa in the second metastasis but not in the first metastasis or the primary lesion suggests that activation of c-rasHa may be a late event in the malignant progression of HPV-18-associated penile squamous cell carcinoma. Analysis of additional samples from primary lesions and their resultant metastases is necessary to elucidate the incidence and significance of c-rasHa activation in penile squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed1998

Treatment with finasteride preserves usefulness of prostate-specific antigen in the detection of prostate cancer: results of a randomized, double-blind, placebo-controlled clinical trial. PLESS Study Group. Proscar Long-term Efficacy and Safety Study.

OBJECTIVES: To evaluate prostate cancer detection and prostate-specific antigen (PSA) among men with benign prostatic hyperplasia treated with finasteride. METHODS: Three thousand forty men 45 to 78 years of age with PSA less than 10 ng/mL and no history of prostate cancer were randomized in a double-blind, placebo-controlled trial to finasteride (n = 1524) or placebo (n = 1516) for up to 4 years. A prerandomization biopsy negative for prostate cancer was obtained in 98% of patients with a screening PSA of 4.0 ng/mL or more, and an end-of-study biopsy was requested of all such patients without a recent second negative biopsy or a prostate cancer diagnosis. RESULTS: Overall, 644 patients (21%) underwent biopsy and 201 (6.6%) underwent transurethral resection of the prostate. Prostate cancer was diagnosed in 4.7% of men on finasteride and 5.1% on placebo (P = 0.7). Elevated PSA prompted diagnosis in 35% of cases on finasteride and 34% on placebo. The area under the receiver operating characteristic curve for last PSA was 0.84 on finasteride and 0.79 on placebo (P = 0.07). Use of an upper limit of normal for last PSA of 2.0 ng/mL for finasteride and 4.0 ng/mL for placebo yielded similar sensitivity (66% versus 70%, P = 0.6), higher specificity (82% versus 74%, P < 0.0001), and a higher likelihood ratio (3.6 versus 2.7, P < 0.05) for finasteride than for placebo. CONCLUSIONS: In men treated with finasteride, multiplying PSA by 2 and using normal ranges for untreated men preserves the usefulness of PSA for prostate cancer detection.

Aged↗
PubMed1996

Intracranial metastases as the first manifestation of prostate cancer.

We report on 2 patients with neurologic symptoms secondary to intracranial metastases from carcinoma of the prostate. In one of these patients, the intracranial lesion was the only clinically detectable metastasis. We have found only three other such cases reported in the English-language literature.

Adenocarcinoma↗
PubMed1996

Retroviral transduction of transforming growth factor-beta1 induces pleiotropic benign prostatic growth abnormalities in mouse prostate reconstitutions.

Transforming growth factor-beta1 (TGF-beta1) plays an important role in the normal growth and differentiation of the mouse prostate with accumulations of extracellular TGF-beta1 in fetal and neonatal prostate tissues particularly at epithelial-mesenchymal interfaces. We have demonstrated increased accumulation of TGF-beta1 in areas of human prostates with benign prostatic hyperplasia and adenocarcinoma by immunohistochemistry. To study the role of TGF-beta1 in pathologic processes, we constructed retroviruses that express the cDNA for murine TGF-beta1 along with either a dominant selectable geneticin (G418) resistance (Neo) gene, BabeTGF-beta1Neo, or a histochemically detectable beta-galactosidase gene, BabeTGF-beta1Gal. The biologic activity of these retroviruses was evaluated in vitro in NIH3T3 fibroblasts and in vivo using the mouse prostate reconstitution (MPR) model. Expression of the retrovirus in MPR was confirmed by beta-galactosidase staining and by reverse transcription followed by PCR for the virus-encoded RNA. Pathologic evaluation of hematoxylin and eosin-stained sections was complemented by immunohistochemical analysis of cytokeratin and neuronal markers. TGF-beta1 transducing retrovirus infection did not have an effect on total growth of the MPR; however, changes in the growth and distribution of specific cell types were observed. A phenotype of benign hyperplasia that involved increased numbers of cytokeratin 14-positive cells characteristic of basal epithelial cells was observed. Immunohistochemical studies colocalized an increased accumulation of extracellular TGF-beta1 with these cytokeratin 14 expressing hyperplastic lesions, An increase in stromal abnormalities was also observed and included a significant increase in the density of neuronal cells. The TGF-beta1-induced hyperplastic response involving basal epithelial cells may be the result of paracrine stimulation of growth of specific cell types in the prostate and may represent a divergence of normal growth processes. Benign growth abnormalities of basal epithelial cells in the human prostate have also been reported. An increased density of neuronal cells and other stromal abnormalities in response to TGF-beta1 retroviral transduction is also consistent with benign growth abnormalities in the human prostate.

3T3 Cells↗
PubMed1996

Pitfalls in interpreting prostate specific antigen velocity.

PURPOSE: The concept of prostate specific antigen (PSA) velocity as an improved marker for prostate cancer detection is intriguing. However, before this concept is applied to individual patients several confounding parameters must be addressed. We determined the variability of serum PSA levels in men without prostate cancer. MATERIALS AND METHODS: We reviewed data from a prostate cancer screening program, and determined inter-assay and individual variability of the serum PSA values for a 2-year followup period in 265 men clinically free of prostate cancer. RESULTS: Our average inter-assay coefficient of variation was 7.5%. Therefore, we considered only PSA changes exceeding +/- 15% as significant. Fluctuations in serum PSA occurred in 78% of the men during the observation period, and 12.5% had at least a single PSA increase exceeding 0.75 ng/ml. per year. Fluctuations were noted throughout the entire range of serum PSA levels but became progressively larger with an increasing mean PSA. CONCLUSIONS: The inter-assay variability must be considered when interpreting PSA velocity. Individual fluctuations in serum PSA dictate an observation period of at least 2 years before PSA velocity is considered abnormal.

Adult↗
PubMed1995

Loss of p53 function leads to metastasis in ras+myc-initiated mouse prostate cancer.

To study the interactions between dominantly acting oncogenes and tumor suppressor genes we used p53 'knockout' mouse urogenital sinus tissue for retroviral transduction of ras and myc in the mouse prostate reconstitution (MPR) model system. Epithelial hyperplasia was observed in all wild-type p53 MPRs with one small focal cancer and no evidence of metastasis. Prostatic cancer was found in 100% of the heterozygous and homozygous p53 mutant MPRs with metastatic deposits in 95% of the mice. The pattern of metastasis was remarkably similar to that in human prostate cancer with gross metastatic deposits in the lung, lymph nodes, bone and liver of many animals. Progression of carcinomas in the ras+myc-initiated heterozygous p53 mutant MPRs was invariably associated with either complete loss, partial deletion or loss of expression of the wild-type p53 allele. Southern blotting analysis of proviral-cellular DNA junction fragments in primary carcinomas and cell lines derived from metastatic deposits revealed that metastases do not necessarily seed out from the most abundant clone in the primary carcinoma.

Alleles↗
PubMed1995

Mesenchymal-epithelial interactions and transforming growth factor-beta 1 expression during normal and abnormal prostatic growth.

Mesenchymal-epithelial interactions are associated with growth and morphogenesis of the prostate. We have detected three isoforms of transforming growth factor beta (TGF-beta) in the developing mouse prostate that may mediate some of these interactions. Separation of the fetal urogenital sinus (UGS) tissue into mesenchymal and epithelial components indicated that mRNA expression of TGF-beta 1, 2, and 3 was more abundant in the mesenchyme compared to the epithelium. Immunohistochemical analysis revealed accumulation of TGF-beta 1 in the mesenchyme surrounding ductules in the UGS and neonatal prostate. Further analysis of TGF-beta 1 localization in surgically removed adult human prostate tissues revealed more intense staining associated with regions of abnormal growth compared to normally appearing tissue. The percent of the total stained area with extracellular accumulation of TGF-beta 1 was 59% in prostate cancer, 26% in benign prostatic hyperplasia (BPH), and 8.6% in normal tissue. In additional immunohistochemical studies we observed that intracellular TGF-beta 1 was predominantly associated with the epithelial cells in prostate cancer (epithelial cells = 33.5% of the total stained area, stromal cells = 13.3%, and unstained = 53.2%), whereas in BPH intracellular TGF-beta 1 was predominantly associated with stromal cells (stromal cells = 32.2% of the total stained area, epithelial cells = 12.3%, and unstained = 55.5%). Although additional experimental and clinical studies are needed to better understand the relationships between TGF-beta 1 and abnormal prostatic growth, our observations thus far suggest a role for TGF-beta 1 in the development of benign and malignant growth abnormalities in the prostate. One approach to establishing the pathobiological significance of TGF-beta 1 accumulation in the prostate is by introducing and overexpressing the TGF-beta 1 cDNA in prostate tissue using the mouse prostate reconstitution model system. We discuss applicability of transgenic animal and organ reconstitution models for experimental studies concerning TGF-beta-induced prostate growth abnormalities.

Animals↗
PubMed1995

Transforming growth factor-beta localization during mouse prostate morphogenesis and in prostatic growth abnormalities.

Growth and morphogenesis of the prostate involves mesenchymal-epithelial interactions. Transforming growth factor-beta 1 (TGF-beta1) is one growth factor that may play a role in these paracrine interactions. We have localized TGF-beta1 by molecular and immunohistochemical analysis in the developing mouse prostate. Accumulations of TGF-beta1 protein were localized in the mesenchyme surrounding ductules in fetal and neonatal prostate. Previous studies in the mouse prostate reconstitution (MPR) model system have localized accumulations of TGF-beta1 to regions of oncogene-induced abnormalities. In surgically excised adult human prostate tissues, localized accumulations of TGF-beta1 are associated with prostate cancer and benign prostatic hyperplasia (BPH). Intracellular TGF-beta1 was more often associated with stromal cells in BPH and with neoplastic epithelial cells in prostate cancer. The production and accumulation of TGF-beta1 appears to involve interactions between mesenchymal and epithelial cells. Further experimental studies may clarify the relationships between TGF-beta1 and abnormal prostatic growth.

Animals↗
PubMed1995

Treatment with finasteride following radical prostatectomy for prostate cancer.

OBJECTIVES: The objective of this study was to evaluate the effect of finasteride (10 mg/d) or placebo on serum prostate-specific antigen (PSA) and recurrence rates in men with detectable PSA levels after radical prostatectomy. METHODS: A total of 120 men, 48 to 89 years old, previously treated with radical prostatectomy for prostate cancer within the past 10 years, with serum PSA levels between 0.6 and 10.0 ng/mL, with no evidence of skeletal metastasis on bone scan, and with no previous androgen deprivation therapy, were treated with 10 mg finasteride or placebo in a double-blind fashion for 12 months. After the first year, all patients were treated with finasteride for an additional 12 months. Primary endpoints were serum PSA levels and recurrence rates defined as positive bone scan or positive biopsy. RESULTS: Patients treated with finasteride had a delayed increase in serum PSA compared with placebo of approximately 9 months in the first year and 14 months by the end of the second year. Patients with baseline PSA levels less then 1.0 ng/mL had no significant increase in serum PSA during the 2 years of treatment. Fewer recurrences were observed in the finasteride group, but these differences were not statistically significant. Finasteride was well tolerated, and side effects were balanced between treatment groups. CONCLUSIONS: The results of this study indicate that treatment with finasteride delays but does not prevent the rise in serum PSA observed in untreated patients with detectable PSA levels after radical prostatectomy. The reduction in local and distant recurrences in the finasteride group suggests that the effect on PSA reflects a direct effect on tumor growth without affecting the initial response to subsequent hormonal therapy. These data require confirmation by studies that are longer and larger, focused on demonstrating significant differences in progression rates and survival before the use of finasteride can be considered as an option for men with detectable PSA levels after radical prostatectomy.

Aged↗
PubMed1994

Mesenchymal-epithelial interactions and transforming growth factor-beta expression during mouse prostate morphogenesis.

To explore the role of transforming growth factor-beta (TGF beta) isoforms and other growth-related genes during prostate morphogenesis in the mouse, we examined mRNA levels in fetal day 17 urogenital sinus, mesenchyme (UGM), and epithelium (UGE) as well as in the ventral, dorsal, and anterior lobes of the adult prostate. In addition, we used antiserum specific for extracellular TGF beta 1 in immunohistochemical studies to localize accumulation of the TGF beta 1 isozyme in the above tissues as well as those derived from fetal day 19 and neonatal mouse prostate. Differential patterns of expression in fetal and adult tissues were seen. TGF beta 1, -beta 2, and -beta 3 expression was substantially elevated in UGM compared to that in UGE, yet only TGF beta 1, not TGF beta 2 or TGF beta 3, mRNA levels were sustained in adult prostate tissues. High levels of accumulation of TGF beta 1 were demonstrated by immunohistochemistry in the mesenchymal compartment compared to those in the epithelial compartment throughout development. Interestingly, the highest levels of TGF beta 1 appeared in areas of active epithelial duct formation and delineated the mesenchymal architectural changes necessary for ductal network formation. Additional studies revealed that levels of mRNAs for other genes involved in tissue remodeling and growth were also elevated in UGM compared to those in UGE. Tissue plasminogen activator, urokinase plasminogen activator, androgen receptor, and c-myc mRNA levels were also elevated in UGM compared to UGE. Interestingly, whereas tissue plasminogen activator mRNA levels, like those of TGF beta 2 and -beta 3, were barely detectable in adult prostatic tissues, mRNA levels for urokinase plasminogen activator, androgen receptor, and c-myc were readily detected and expressed in a lobe-specific fashion. Overall, these data indicate that expression of TGF beta 1 isoforms and other growth-related genes is associated with mesenchymal cells in areas of active morphogenesis during prostate development and provide objective molecular and cellular information regarding mediators of mesenchymal-epithelial interactions in prostate.

Animals↗
PubMed1993

Dietary fenretinide, a synthetic retinoid, decreases the tumor incidence and the tumor mass of ras+myc-induced carcinomas in the mouse prostate reconstitution model system.

Several epidemiological studies have implicated low dietary and serum levels of retinol with an increased risk for the development of human prostate cancer. In a recent report, dietary fenretinide [N-[(4-hydroxyphenyl)] retinamide], a synthetic retinoid with low toxicity, decreased the incidence of experimentally induced prostate cancer. Fenretinide is currently being evaluated in phase I and phase II clinical trials as an agent for both the treatment and chemoprevention of human prostate cancer. Because of these findings, we investigated whether dietary fenretinide could alter the incidence of phenotype of oncogene-induced prostate cancer in the mouse prostate reconstitution model system. When compared to control-fed animals, dietary fenretinide reduced the tumor incidence by 49% and the tumor mass by 52% of ras+myc-induced cancers in the mouse prostate reconstitution model system, which was modified to prolong the latency period before cancer development. Retinoids have a wide ranging effect on cellular differentiation, growth factor synthesis, and immune function. While its mechanism of action in this system remains unclear, fenretinide is an effective agent for the chemoprevention and growth modulation of oncogene-induced prostate cancer in the mouse prostate reconstitution model system and may be effective for the chemoprevention of human prostate cancer.

Animals↗
PubMed1993

Transgenic models for the study of prostate cancer.

Transgenic model systems provide tools for obtaining information that clarifies important relationships between genetic alterations and carcinogenesis. One such relationship is the induction of specific growth factor activities by dominantly acting oncogenes. Using a "transgenic organ" model referred to as mouse prostate reconstitution (MPR) under conditions where the ras and myc oncogenes were introduced using a recombinant retrovirus into both the mesenchymal and epithelial compartments of the urogenital sinus, poorly differentiated prostate cancer (PC) was produced with high frequency (> 90%) in inbred C57BL/6 mice. Time-course studies using northern blotting and immunohistochemical analysis showed that the transition from benign to malignant status invariably was associated with the induction of elevated transforming growth factor-beta 1 (TGF-beta 1) expression. Additional immunohistochemical analysis of TGF-beta 1 in human PC and benign prostatic hyperplasia (BPH) showed that positive extracellular staining was significantly more extensive in PC compared with BPH. This differential staining pattern was evident in focal areas of PC adjacent to BPH. These findings in both the MPR model system and human PC suggest that elevated TGF-beta 1 expression is involved in the progression to malignancy and that its pattern of expression may become a useful marker of PC. Additional studies using transgenic animal models will continue to provide important clinically useful information about PC in man.

Animals↗
PubMed1993

Genetic predisposition and mesenchymal-epithelial interactions in ras+myc-induced carcinogenesis in reconstituted mouse prostate.

Using a mouse prostate reconstitution (MPR) model system, strain-specific responses to the ras and myc oncogenes were investigated. When ras + myc were introduced into both the mesenchymal and epithelial compartments of the urogenital sinus, poorly differentiated prostate cancer was produced at a high frequency (> 90%) in inbred C57BL/6 mice. In contrast, under similar conditions, inbred BALB/c MPRs formed benign prostatic hyperplasia that converted to cancer at a low frequency (< 10%). Restricting the oncogenes to the mesenchymal or epithelial compartments revealed that oncogene activities were more pronounced in the mesenchyme of C57BL/6 mice and resulted in elevated transforming growth factor-beta 1 expression along with a severe desmoplastic reaction. Heterologous MPRs composed of BALB/c mesenchyme and C57BL/6 epithelium or vice versa demonstrated that intrinsic properties of BALB/c mesenchyme can arrest the progression of ras + myc-initiated C57BL/6 epithelium from benign hyperplasia to malignant carcinoma.

Animals↗
PubMed1993

Association of transforming growth factor-beta 1 with prostate cancer: an immunohistochemical study.

Prostate tissue samples from patients with prostatic carcinoma (PC) and/or benign prostatic hyperplasia (BPH) were examined for expression of transforming growth factor-beta 1 (TGF-beta 1) using an immunohistochemical technique. Tissues were stained with CC and LC antisera, which react with extracellular and intracellular TGF-beta 1, respectively. All PC and BPH tissues showed positive extracellular staining; however, CC-immunoreactive material was significantly more extensive in PC compared with BPH, the average positively staining areas being 59% and 26%, respectively. This differential staining pattern was evident in cases in which areas of PC were located adjacent to areas of BPH. LC staining was identified exclusively intracellularly involving both stromal and epithelial cells in cases of PC as well as BPH. However, while stromal cell staining was more pronounced in BPH, epithelial cell staining tended to be more extensive and more intense in PC. The findings suggest that TGF-beta 1 may be biologically important in the development of PC and BPH.

Adenocarcinoma↗