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Biomedical subjects

D Petrylak

Publications and source records attributed to D Petrylak.

12 recordsLinked to original sources
PubMed2001

Cure of undifferentiated small cell carcinoma of the urinary bladder with M-VAC chemotherapy.

Small cell carcinoma (SCC) of the urinary bladder is a rare, aggressive malignancy with approximately 135 cases reported in the literature. Treatments have included chemotherapy, radical surgery, radiotherapy, and combinations of these. We present the apparent cure of a 73-year-old man who presented with clinical stage T2 SCC of the urinary bladder. He was treated with three cycles of methotrexate, vinblastine, Adriamycin (doxorubicin), and cisplatin (M-VAC) chemotherapy. Subsequent radical cystoprostatectomy revealed no pathologic evidence of tumor. The patient is alive and well with no evidence of recurrence 3 years post cystectomy. A brief review of the literature is also presented.

Journal Article↗
PubMed2000

A phase II pilot study of KW-2189 in patients with advanced renal cell carcinoma.

BACKGROUND: KW-2189 is a semi-synthetic, water-soluble analog of duocarmycin B2, a new class of potent antitumor antibiotics produced by streptomyces, with improved in vitro antitumor potency. PATIENTS AND METHODS: Forty patients with pathologically confirmed metastatic renal cell carcinoma were treated in this multicenter, open-label phase II trial. All patients received 0.4 mg/m2 KW-2189 as an i.v. infusion for Cycle I. Cycles were repeated every 5 to 6 weeks with escalations to 0.5 mg/m2 in the absence of significant toxicity or disease progression. RESULTS: No patient had an objective response. The most common drug-related toxicity was hematological-delayed neutropenia and thrombocytopenia, with recovery by week 6. Non-hematologic toxicity consisted of mild to moderate fatigue, nausea and vomiting, and anorexia that was generally manageable. CONCLUSIONS: KW-2189 in this dose and schedule has a predictable safety profile of reversible myelosuppression. No activity in metastatic renal cell carcinoma was demonstrated.

Antibiotics, Antineoplastic↗
PubMed1999

Docetaxel (Taxotere) and estramustine versus mitoxantrone and prednisone for hormone-refractory prostate cancer: scientific basis and design of Southwest Oncology Group Study 9916.

Hormone-refractory prostate cancer is the terminal step in the natural history of prostate cancer. To date, no chemotherapeutic agents have been shown to impact clinical outcome at this stage. Recently, the Food and Drug Administration approved the combination of mitoxantrone and prednisone based solely on its superior palliative effects as compared to steroids alone in 2 randomized trials. Progress in biologically driven drug development has led to the identification of several estramustine-based regimens that, although based on single institution experience, appear to have at least a comparable but very promising level of activity in hormone-refractory prostate cancer patients. One such combination, estramustine plus docetaxel (Taxotere; Rhône-Poulenc Rorer, Collegeville, PA), is particularly attractive because of its convenient schedule and side effect profile. To objectively assess the therapeutic benefit of this combination, the Southwest Oncology Group is initiating a randomized phase III trial comparing estramustine and docetaxel with the standard arm of mitoxantrone and prednisone using time to progression and survival as the primary end points. Secondary end points will include toxicity profiles, assessments of quality of life parameters, and magnitude of decline of prostate-specific antigen levels between the two treatment arms.

Adenocarcinoma↗
PubMed1996

Upregulation of prostate-specific membrane antigen after androgen-deprivation therapy.

OBJECTIVES: To determine the expression of prostate-specific membrane antigen (PSMA) before and after androgen-deprivation therapy and to compare PSMA expression with prostate-specific antigen (PSA) expression. METHODS: We studied specimens from 20 patients with prostate cancer undergoing medical or surgical castration or combination androgen-deprivation therapy in whom matched pretreatment and post-treatment tissue specimens were available and 16 patients in whom only a post-treatment specimen was available. The expression of PSMA and PSA in the tissue specimens was determined by immunoperoxidase staining. The extent of staining was calculated by multiplying the percent of antigen-positive tumor cells by the staining intensity to arrive at a stain index for each biomarker. An in vitro study assessed the concentration of PSMA and PSA in extracts of LNCaP cells cultured in the presence or absence of androgen as determined by immunoassays and Western blot analysis. RESULTS: PSMA reactivity was found to be increased in 55% (11 of 20) of post-treatment primary tissues and 100% (4 of 4) of post-treatment metastatic specimens. In contrast, PSA expression was found to be decreased in 70% (14 of 20) of post-treatment primary and 100% (4 of 4) of post-treatment metastatic specimens. Neither type of androgen-deprivation treatment nor tissue sensitivity to androgen deprivation appeared to influence degree of biomarker expression. PSMA was found to be downregulated and PSA upregulated when LNCaP cells were cultured in the presence of testosterone or dihydrotestosterone. CONCLUSIONS: The enhanced expression of PSMA in tissues and LNCaP cells after androgen deprivation suggests that PSMA is upregulated in the majority of prostate carcinomas after androgen treatment. The high expression in metastatic tissues strongly suggests that PSMA may be a clinically useful target for antibody-and genetic-directed therapy of prostate cancer that recurs after androgen deprivation. The mechanism whereby androgens suppress the expression of PSMA, and the association of PSMA with the development of hormone-independent prostate cancers, will require further study.

Androgen Antagonists↗
PubMed1995

Effects of suramin-related and other clinically therapeutic polyanions on protein kinase C activity.

The mechanism of the antineoplastic effects of suramin may involve interference with signal transduction, but in general is not well understood. We examined several polyanions to determine their effects on the kinase activity of the protein kinase C (PKC) beta1 and other PKC isoforms. Similar to suramin, a phosphorothioate oligodeoxynucleotide 28-mer homopolymer of cytidine (SdC28) inhibited the phosphatidylserine and Ca2+-dependent phosphorylation of an epidermal growth factor receptor octapeptide substrate. The inhibition by suramin was mixed competitive/noncompetitive with respect to ATP, but uncompetitive with respect to substrate. In contrast, the inhibition by SdC28 was competitive with respect to substrate (Ki = 5.4 microM) and not competitive with respect to ATP. The PKC alpha and beta1 isoforms were inhibited to the same extent with SdC28, while PKC epsilon was not inhibited. SdC28, in the absence of lipid cofactor, stimulated substrate phosphorylation, and in the absence of substrate induced PKC beta1 autophosphorylation. Similar behavior was seen with another polyanion, the polysulfated carbohydrate pentosan polysulfate (polyxylyl hydrogen sulfate). H4, a bis-naphthalene disulfonate tetraanion structurally related to suramin, also inhibited kinase activity but was not competitive with respect to ATP. Dianions closely related to H4 failed to inhibit PKC beta1, suggesting that multiple (>2) negative charges are required. The interactions of polyanions with PKC are complex, and are dependent on the molecular structure of the polyanion, the presence of cofactors, and the PKC isoform.

Animals↗
PubMed1995

Changing pattern of expression of the epidermal growth factor receptor and transforming growth factor alpha in the progression of prostatic neoplasms.

The autocrine/paracrine interaction of the epidermal growth factor receptor (EGFr) and transforming growth factor alpha (TGF-alpha) has been implicated in prostate cancer cell growth and proliferation. To evaluate the role of EGFr and TGF-alpha in prostate cancer progression, we studied the immunohistochemical staining pattern of EGFr and TGF-alpha in malignant primary and hormone-independent metastatic prostate lesions. The specimens evaluated included 37 primary carcinomas (34 hormone-naive and 3 hormone-refractory tumors) and 22 metastases. For each specimen, the pattern of expression was evaluated and staining reactivities graded from 0-3, with 0 representing no staining and 3 representing homogeneous and intense staining. Primary malignant prostate epithelial cells in areas with discrete gland formation showed strong EGFr immunostaining, while stromal cells were generally nonreactive. In untreated primary tumors, TGF-alpha expression was primarily in the stroma, while epithelial cells were weakly positive in several cases. Malignant epithelial cells adjacent to neural elements that stained positive for TGF-alpha was frequently observed. A homogeneous staining pattern for EGFr was noted in 17 (89%) of 19 evaluable androgen-independent-refractory metastases, while TGF-alpha expression was found in 14 (78%) of 18 evaluable cases. Overall, 14 of 18 androgen-independent metastases coexpressed the receptor and the ligand. These results suggest that, unlike primary prostate tumors where a paracrine relationship between EGFr and TGF-alpha appears to predominate, the potential for autocrine stimulation may exist in the majority of metastatic androgen-independent tumors. Furthermore, the changing pattern of expression as the disease evolves from the localized hormone-naive to metastatic androgen-independent condition suggests that strategies aimed at blocking this growth factor pathway may be of therapeutic importance for androgen-independent disease.

Adrenal Gland Neoplasms↗
PubMed1993

Cytotoxic chemotherapy for advanced hormone-resistant prostate cancer.

BACKGROUND: Advanced adenocarcinoma of the prostate after hormonal manipulation has been noted to be a relatively chemotherapeutic nonresponsive tumor. Earlier reviews have reported objective responses, that is, complete and partial remissions in 6.5% of 3184 patients, and the current review examines the efficacy of new agents. METHODS: The current review consists of 26 new drug trials culled from papers and abstracts published between 1987-1991. RESULTS: Results of these 26 drug trials found a similar trend, 8.7% (95% confidence interval, 6.4-9.0%), indicating that hormone-resistant adenocarcinoma of the prostate still fails to respond to most cytotoxic agents. The most interesting of the new therapeutic agents is the combination of vinblastine plus estramustine. Only six agents had an objective response rate greater than 10%, such as vinblastine by continuous infusion, trimetrexate, mitoguazone, and estramustine. The recent introduction of radioactive-labeled monoclonal antibodies is intriguing and these will undoubtably be used as carriers for radiotherapeutic and cytotoxic compounds. CONCLUSIONS: Although multidrug resistance may explain the marginal efficacy of cytotoxic drugs, methods to overcome such resistance and, more importantly, new classes of agents must be developed. In addition, reliable disease markers must be found for osseous and visceral metastases to avoid the prevailing confusion in evaluating more precisely the destruction of prostate cancer cells.

Antibodies, Monoclonal↗
PubMed1993

Cytotoxic chemotherapy for advanced renal cell carcinoma.

This article reviews 72 cytotoxic chemotherapeutic agents used singly or in a limited number of two drug combinations. Results in 3502 adequately treated patients show objective response (complete and partial remissions) in only 197 or 5.6% (95% CI, 4.8% to 6.4%). Although some data suggest that a few drugs need further evaluation, at this time, renal cell carcinoma must be considered a chemotherapeutically resistant cancer.

Antineoplastic Agents↗
PubMed1992

Altered expression of the retinoblastoma gene product: prognostic indicator in bladder cancer.

BACKGROUND: It has been reported that 50%-70% of patients with bladder cancer experience recurrence after initial successful treatment and about 10%-20% of these patients die of the disease. Despite precise pathologic staging and grading, we are unable to predict clinical outcome in all patients. The retinoblastoma-susceptibility (RB) gene, a prototype of tumor suppressor genes, has recently been associated with development and/or progression of bladder cancer, as well as sarcoma and small-cell lung cancer. In transitional cell carcinomas of the bladder, we have observed altered expression of the Rb gene product--a nuclear phosphoprotein thought to function as a cell cycle regulator. PURPOSE: The aim of this study was to investigate the hypothesis that altered patterns of Rb expression correlate with prognosis in bladder cancer. METHODS: Expression of the RB gene was evaluated in specimens from 48 primary bladder tumors obtained by cystectomy or transurethral resection. Rb protein expression was correlated with disease outcome in these patients. Rb expression was examined by immunohistochemistry, using the mouse monoclonal antibody Rb-PMG3-245 on frozen tissue sections. Computerized image analysis was used to quantify the level of Rb protein in individual tumor cells. RESULTS: The overall 5-year disease-free survival was 66%, with a median follow-up of 42 months. Normal levels of Rb protein expression were found in 34 patients (Rb-positive group). A spectrum of altered patterns of expression from undetectable levels to heterogeneous expression, however, was observed in 14 patients (altered Rb group). Of the 38 patients with muscle-invasive tumors, 13 were categorized as having altered expression of Rb protein. Only one of 10 patients with superficial carcinomas had altered expression of Rb protein. The 5-year survival was significantly decreased in patients with altered Rb protein compared with the survival in patients with positive Rb expression (P less than .001). CONCLUSIONS: The results suggest that tumors exhibiting decreased expression of the RB gene-coded product (Rb protein) had a more aggressive biological behavior than those that expressed the Rb protein in the majority of their tumor cells. IMPLICATIONS: This study demonstrates that altered patterns of Rb protein expression may be an important prognostic variable in patients presenting with invasive bladder cancer.

Adult↗
PubMed1992

Estramustine and vinblastine: use of prostate specific antigen as a clinical trial end point for hormone refractory prostatic cancer.

The combination of estramustine phosphate and vinblastine sulfate, 2 agents with separate and unique antimicrotubular effects, has demonstrated additive cytotoxicity against the DU145 human prostate derived cell line in vitro. We evaluated this combination in 25 patients with progressive hormone refractory prostate cancer. Of 24 patients with an elevated prostate specific antigen (PSA) level at the start of treatment 13 (54%, 95% confidence limits 34 to 74%) had a greater than 50% decrease in PSA levels on at least 3 consecutive biweekly determinations. The median decrease in PSA in responding patients was 64% (mean 71.7%) and the median duration of response was 7 months. In 5 patients with bidimensionally measurable disease 2 partial responses were observed. Treatment was well tolerated, with mild and manageable toxicity. This is a well tolerated outpatient treatment regimen for patients with hormone-refractory prostatic cancer which deserves further investigation.

Aged↗