RESUMEN
Endoglin is a transforming growth factor beta (TGFbeta) superfamily auxiliary receptor. We had previously shown that it suppressed prostate cancer (PCa) cell motility, and that its expression was lost during PCa progression. The mechanism by which endoglin inhibits PCa cell motility is unknown. Here we demonstrate that endoglin abrogates TGFbeta-mediated cell motility, but does not alter cell surface binding of TGFbeta. By measuring Smad-specific phosphorylation and Smad-responsive promoter activity, endoglin was shown to constitutively activate Smad1, with little-to-no effect upon Smad3. Knockdown of Smad1 increased motility and abrogated endoglin's effects. As type I activin receptor-like kinases (ALKs) are necessary for Smad activation, we went on to show that knockdown of ALK2, but not TGFbetaRI (ALK5), abrogated endoglin-mediated decreases in cell motility and constitutively active ALK2 was sufficient to restore a low-motility phenotype in endoglin deficient cells. These findings provide the first evidence that endoglin decreases PCa cell motility through activation of the ALK2-Smad1 pathway.
Asunto(s)
Receptores de Activinas Tipo I/fisiología , Antígenos CD/fisiología , Movimiento Celular/fisiología , Neoplasias de la Próstata/patología , Receptores de Superficie Celular/fisiología , Proteína Smad1/fisiología , Western Blotting , Línea Celular Tumoral , Endoglina , Citometría de Flujo , Humanos , Masculino , Neoplasias de la Próstata/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Coupling array technology to laser capture microdissection (LCM) has the potential to yield gene expression profiles of specific cell populations within tissue. However, remaining problems with linear amplification preclude accurate expression profiling when using the low nanogram amounts of RNA recovered after LCM of human tissue. We describe a novel robust method to reliably amplify RNA after LCM, allowing direct probing of 12K gene arrays. The fidelity of amplification was demonstrated by comparing the ability of amplified RNA (aRNA) versus that of native RNA to identify differentially expressed genes between two different cell lines, demonstrating a 99.3% concordance between observations. Array findings were validated by quantitative polymerase chain reaction analysis of a randomly selected subset of 32 genes. Using LCM to recover normal (N=5 subjects) or cancer (N=3) cell populations from intact human prostate tissue, three differentially expressed genes were identified. Independent investigators have previously identified differential expression of two of these three genes, hepsin and beta-microseminoprotein, in prostate cancer. Taken together, the current study demonstrates that accurate gene expression profiling can readily be performed on specific cell populations present within complex tissue. It also demonstrates that this approach efficiently identifies biologically relevant genes.
Asunto(s)
Perfilación de la Expresión Génica/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Neoplasias de la Próstata/genética , Línea Celular Tumoral , Células Epiteliales/patología , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Microdisección/métodos , Análisis de Secuencia por Matrices de Oligonucleótidos , Reacción en Cadena de la Polimerasa , Próstata/citología , Neoplasias de la Próstata/patología , ARN Neoplásico/genética , ARN Neoplásico/aislamiento & purificación , Reproducibilidad de los Resultados , Transcripción Genética/genética , Células Tumorales CultivadasRESUMEN
Although cell invasion is a necessary early step in cancer metastasis, its regulation is not well understood. We have previously shown, in human prostate cancer, that transforming growth factor beta (TGFbeta)-mediated increases in cell invasion are dependent upon activation of the serine/threonine kinase, p38 MAP kinase. In the current study, downstream effectors of p38 MAP kinase were sought by first screening for proteins phosphorylated after TGFbeta treatment, only in the absence of chemical inhibitors of p38 MAP kinase. This led us to investigate mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2), a known substrate of p38 MAP kinase, as well as heat-shock protein 27 (HSP27), a known substrate of MAPKAPK2, in both PC3 and PC3-M human prostate cells. After transient transfection, wild-type MAPKAPK2 and HSP27 both increased TGFbeta-mediated matrix metalloproteinase type 2 (MMP-2) activity, as well as cell invasion, which in turn was inhibited by SB203580, an inhibitor of p38 MAP kinase. Conversely, dominant-negative MAPKAPK2 blocked phosphorylation of HSP27, whereas dominant-negative MAPKAPK2 or mutant, non-phosphorylateable, HSP27 each blocked TGFbeta-mediated increases in MMP-2, as well as cell invasion. Similarly, knock down of MAPKAPK2, HSP27 or both together, by siRNA, also blocked TGFbeta-mediated cell invasion. This study demonstrates that both MAPKAPK2 and HSP27 are necessary for TGFbeta-mediated increases in MMP-2 and cell invasion in human prostate cancer.
Asunto(s)
Adenocarcinoma/enzimología , Proteínas de Choque Térmico/fisiología , Metaloproteinasa 2 de la Matriz/metabolismo , Invasividad Neoplásica , Proteínas de Neoplasias/fisiología , Neoplasias de la Próstata/enzimología , Proteínas Quinasas/fisiología , Factor de Crecimiento Transformador beta/fisiología , Proteínas Quinasas p38 Activadas por Mitógenos/fisiología , Adenocarcinoma/patología , Línea Celular Tumoral/efectos de los fármacos , Línea Celular Tumoral/enzimología , Activación Enzimática/efectos de los fármacos , Proteínas de Choque Térmico HSP27 , Humanos , Imidazoles/farmacología , Péptidos y Proteínas de Señalización Intracelular , Masculino , Chaperonas Moleculares , Neoplasias de la Próstata/patología , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas , Piridinas/farmacología , Interferencia de ARN , ARN Interferente Pequeño/farmacología , Proteínas Recombinantes de Fusión/fisiología , Transducción de Señal/efectos de los fármacos , Transfección , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidoresRESUMEN
Cell growth and differentiation are processes intimately associated with carcinogenesis and regulated by tyrosine kinases and other signaling proteins. Identification of drugs that target signaling molecules is hampered by both the large number of targets and the complex nature of signaling cascades. Optimal development of chemopreventive agents must take into account affinity for the target, pharmacology, and safety profile of the agent. Validated biomarkers will allow the optimal implementation of chemopreventive trials. Directed epidemiologic studies can lead to the identification of lead compounds for chemoprevention, such as genistein. Therefore, agents targeted to pathways and molecules of known biological importance in the prostate hold the promise of clinical efficacy against prostate cancer in a chemopreventive setting.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Anticarcinógenos/uso terapéutico , Inhibidores Enzimáticos/uso terapéutico , Neoplasias de la Próstata/prevención & control , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Receptor ErbB-2/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Transferasas Alquil y Aril/antagonistas & inhibidores , Farnesiltransferasa , Genisteína/uso terapéutico , Humanos , MasculinoRESUMEN
BACKGROUND AND AIM: At the present time there is an explosion of research in the area of gene arrays, and their application for detection of genes related to disease as well as its therapeutic manipulation. However, as individual arrays are expensive, comparisons of gene expression are often not repeated. In the current study, gene array experiments were repeated multiple times in order to understand the variability associated with measurements of gene expression. By focusing upon the pharmacologically important target of prostate cancer cell detachment, the current study employed multiple repeats of gene array experiments. This was used as a model system to demonstrate the utility of the experimental approach and statistical methods used. METHODS: To identify genes involved in detachment of prostate cancer cells (a prerequisite for metastases), we analyzed gene expression changes in metastatic variant PC3-M cells undergoing spontaneous detachment in culture. The data were interpreted using an elementary statistical approach. The between-experiment and within-repeated-observations variability in expression of 3582 genes possibly related to prostate cancer was also evaluated. RESULTS: One important gene related to prostate cell detachment was identified, based on the magnitude of its change in expression, as measured by a ratio of the expression after cell detachment and expression before detachment. On average, the variation between experiments was greater by about 30 to 40% than the variation between repeated observations. CONCLUSION: These findings have implications relating to the use of gene arrays to detect variance of gene expression, and should be taken into consideration in the prospective design of array experiments.
Asunto(s)
Perfilación de la Expresión Génica/métodos , Variación Genética , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Adhesión Celular/genética , Perfilación de la Expresión Génica/estadística & datos numéricos , Perfilación de la Expresión Génica/tendencias , Humanos , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos/estadística & datos numéricos , Análisis de Secuencia por Matrices de Oligonucleótidos/tendencias , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Células Tumorales CultivadasRESUMEN
Preclinical models for the identification of prostate cancer chemoprevention agents are lacking. Based upon the notion that clinically useful chemoprevention agents should exhibit selective activity against early stage disease, studies were undertaken to assess whether chemoprevention agents selectively inhibited the growth of early stage prostate cancer, as compared to late stage cancer. First, a series of cell and molecular studies were performed, which, when taken together, validated the use of a panel of prostate cell lines as a model of the different stages of carcinogenesis. Next, therapeutic responsiveness to ten different cytotoxic or chemoprevention agents was evaluated. Chemoprevention agents exhibited selective activity against normal and early transformed prostate tissue, whereas cytotoxic agents were non-specific. Selective activity against early versus advanced prostate cancer cells is identified as a potential screening method for chemoprevention agents.Prostate Cancer and Prostatic Diseases (2001) 4, 81-91
RESUMEN
It has previously been shown that changes in the activity of focal adhesion kinase (FAK), and its binding to beta-1-integrin, accompany genistein-induced adhesion of prostate cells. Consumption of genistein world wide is associated with a lower incidence of metastatic prostate cancer. Early human clinical trials of genistein are under way to evaluate genistein's potential causal role in this regard. Though an important cell adhesion-associated signaling molecule, FAK's role in regulating prostate cell adhesion was not clear. Elucidation of this process would provide important information relating to both biology and potential clinical endpoints. It was hypothesized that FAK activation and complex formation are temporally related in prostate cells, and can thus be separated. Significant activation of FAK was demonstrated when cells adhered to fibronectin, as compared to poly-L-lysine, thus demonstrating that beta-1-integrin plays a significant role in activating FAK. Neither FAK activation, nor FAK-integrin complex formation, required beta-1-integrin ligand. However, disruption of the cellular cytoskeleton by cytochalasin D prevented FAK activation, but did not block genistein-induced complex formation. In the face of a disrupted cytoskeleton, signaling through FAK could not be restored through either integrin cross linking, or re-establishment of tensile forces via attachment to solid matrix. These studies demonstrate that FAK-beta-1-integrin complex formation does not require FAK activation, suggesting that it is an early event in prostate cell adhesion. An intact cytoskeleton is necessary for FAK activation. The functional importance of beta-1-integrin in prostate cells is demonstrated. Current findings support plans to test genistein in prostate cancer.
Asunto(s)
Genisteína/farmacología , Integrina beta1/efectos de los fármacos , Proteínas Tirosina Quinasas/metabolismo , Adhesión Celular , Citoesqueleto/metabolismo , Activación Enzimática , Quinasa 1 de Adhesión Focal , Proteína-Tirosina Quinasas de Adhesión Focal , Humanos , Integrina beta1/metabolismo , Masculino , Metástasis de la Neoplasia , Fosforilación , Neoplasias de la Próstata/enzimología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Proteínas Tirosina Quinasas/efectos de los fármacos , Células Tumorales CultivadasRESUMEN
Micromolar concentrations of tamoxifen inhibit the activity of protein kinase C and were recently shown to inhibit prostate cancer cell growth in preclinical studies. Because micromolar concentrations can be attained with high-dose therapy, the clinical activity of high-dose tamoxifen was evaluated in patients with metastatic adenocarcinoma of the prostate. Between December 1993 and February 1997, 30 patients with hormone-refractory metastatic adenocarcinoma of the prostate were continuously administered tamoxifen at 160 mg/m2/day. Therapy was continued until disease progression. All study patients had failed prior treatment with combined androgen blockade, had castrate levels of testosterone, and were heavily pretreated, having received a median of three prior regimens. The average steady-state plasma concentration of tamoxifen was 2.96+/-1.32 microM (mean +/- SD). Grade 3 neurotoxicity was observed in 29% of patients and was rapidly reversible and readily managed with dose modification. Otherwise, grade 3 toxicities were rare. One partial response (80% decline in prostate-specific antigen) was observed (3.3%), whereas disease stabilization was observed in six patients (20%), for a combined partial response/stable disease response rate of 23%. Median time to progression was 2.1 months, and median survival time was 10.5 months. High-dose tamoxifen therapy was well tolerated and associated with micromolar concentrations of tamoxifen in human plasma, and it demonstrated activity, albeit limited, in a heavily pretreated patient cohort with hormone-refractory prostate cancer. These findings suggest that further investigation of the role of protein kinase C modulation in prostate cancer is warranted.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Antineoplásicos Hormonales/efectos adversos , Antineoplásicos Hormonales/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Tamoxifeno/efectos adversos , Tamoxifeno/uso terapéutico , Adenocarcinoma/sangre , Adenocarcinoma/metabolismo , Anciano , Anciano de 80 o más Años , Antineoplásicos Hormonales/sangre , Antineoplásicos Hormonales/farmacocinética , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Resistencia a Antineoplásicos , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Próstata/sangre , Neoplasias de la Próstata/metabolismo , Calidad de Vida , Análisis de Supervivencia , Tamoxifeno/sangre , Tamoxifeno/farmacocinéticaRESUMEN
Raf-1 activation and Bcl-2 hyperphosphorylation following treatment with paclitaxel (Taxol) or other microtubule-active drugs is associated with mitotic arrest. Here we show that microtubule-active drugs do not activate the mitogen-activated protein kinase (MAPK) pathway in leukemia cells. PD98059, a MEK inhibitor, and SB202190, a p38 MAP kinase inhibitor, do not abrogate Bcl-2 phosphorylation nor apoptosis. Simultaneously with PARP cleavage, paclitaxel induces cleavage of Bcl-2 protein yielding a potentially pro-apoptotic 22 kDa product. In comparison, the stimulation of Raf-1 by phorbol ester (TPA) activates the MAPK pathway, causes MAPK-dependent p21WAF1/CIP1 induction, Rb dephosphorylation and growth arrest without Bcl-2 phosphorylation or apoptosis. Like TPA, cAMP induces p21WAF1/CIP1 but does not cause Bcl-2 phosphorylation. MEKK1 and Ras, upstream activators of JNK and ERK MAPK, also fail to induce Bcl-2 hyperphosphorylation. Although Lck tyrosine kinase has been recently implicated in Raf-1 activation during mitotic arrest, microtubule-active drugs induce Raf-1/Bcl-2 hyperphosphorylation and apoptosis in a Lck-deficient Jurkat cells. Therefore, microtubule-active drugs induce apoptosis which is associated with Raf-1 and Bcl-2 phosphorylation and Bcl-2 cleavage but is independent of the MAPK pathway. In contrast, TPA-activated MAPK pathway causes p21WAF1/CIP1-dependent growth arrest without apoptosis.
Asunto(s)
Antineoplásicos Fitogénicos/uso terapéutico , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Leucemia Mieloide/tratamiento farmacológico , Quinasa 1 de Quinasa de Quinasa MAP , Microtúbulos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Proto-Oncogénicas c-raf/metabolismo , Apoptosis/efectos de los fármacos , Genes ras , Humanos , Leucemia Mieloide/metabolismo , Leucemia Mieloide/patología , Paclitaxel/uso terapéutico , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismo , Acetato de Tetradecanoilforbol/uso terapéutico , Células Tumorales CultivadasRESUMEN
p210bcr-abl-Related tyrosine kinase activity has been shown to cause chronic myelogenous leukemia (CML), a disease of bone marrow stem cells. Having previously demonstrated that the aptameric oligonucleotide, ODN-1, could inhibit p210bcr-abl kinase activity, the current study sought to determine if ODN-1 could selectively inhibit the growth of CML cells relative to that of normal bone marrow. ODN-1, when introduced by electroporation into peripheral blood mononuclear cells (PBMC) from patients with CML, decreased the number of committed progenitors (CML CFU-GM) by an average of 67%+/-19% (mean+/-SEM, range 28-98%). Treatment of CML PBMC with ODN-1 was also shown to decrease the number of more primitive cobblestone area-forming cells (CAFC) by 35%-87%. In contrast, there was little suppressive effect by the combination of electroporation and ODN-1 on either CFU-GM or CAFC numbers from normal donor bone marrow. These studies suggest that inhibition of p210bcr-abl protein-tyrosine kinase (PTK) activity by ODN-1 is associated with some degree of selective growth inhibition of p210bcr-abl-transformed cells. p210bcr-abl kinase inhibitory agents may be useful for the ex vivo purging of bone marrow or peripheral blood progenitor/stem cells in the setting of autologous transplantation for CML.
Asunto(s)
División Celular/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Proteínas de Fusión bcr-abl/antagonistas & inhibidores , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Oligodesoxirribonucleótidos/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Animales , Células de la Médula Ósea/citología , Células de la Médula Ósea/efectos de los fármacos , Humanos , Ratones , Células Tumorales CultivadasRESUMEN
BACKGROUND: Inhibition of protein kinase C (PKC) and modulation of transforming growth factor-beta (TGF-beta) are both associated with tamoxifen treatment, and both appear to be important in the regulation of prostate cancer cell growth. Investigations were performed which sought to measure the efficacy, and to elucidate the mechanism of growth inhibition by tamoxifen, in hormone-refractory prostate cancer. METHODS: Growth assays were performed on PC3, PC3-M, and DU145 prostate cancer cells. TGF-beta was measured by ELISA; p21(waf1/cip1) and retinoblastoma (Rb) protein levels were measured by Western blot; PKC activity was measured by kinase assay; and effects upon cell cycle were measured by flow cytometric analysis. RESULTS: IC50s for growth inhibition ranged from 5.5-10 microM, and were not affected by estrogen. Tamoxifen-mediated growth inhibition was not associated with induction of TGF-beta. However, tamoxifen treatment was associated with inhibition of PKC, which was followed by induction of p21(waf1/cip1), Rb dephosphorylation, and G1/S phase cell cycle arrest. Similar effects were observed with the known PKC inhibitor, Ro31-8220. CONCLUSIONS: These data suggest that micromolar concentrations of tamoxifen inhibit prostate cancer cell growth by inhibition of PKC, resulting in induction of the p21(waf1/cip1) protein.
Asunto(s)
Antineoplásicos Hormonales/farmacología , Ciclinas/efectos de los fármacos , Neoplasias de la Próstata/tratamiento farmacológico , Proteína Quinasa C/efectos de los fármacos , Tamoxifeno/farmacología , Factor de Crecimiento Transformador beta/efectos de los fármacos , Antineoplásicos Hormonales/administración & dosificación , División Celular/efectos de los fármacos , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/biosíntesis , Relación Dosis-Respuesta a Droga , Humanos , Técnicas In Vitro , Masculino , Neoplasias de la Próstata/enzimología , Proteína Quinasa C/biosíntesis , Transducción de Señal , Tamoxifeno/administración & dosificación , Factor de Crecimiento Transformador beta/biosíntesisRESUMEN
AIMS AND BACKGROUND: Decitabine (5-aza-2'-deoxycytidine) is an S-phase-specific pyrimidine analog with hypomethylation properties. In laboratory models of prostate cancer (PC-3 and DU-145), decitabine induces cellular differentiation and enhanced expression of genes involved in tumor suppression, immunogenicity, and programmed cell death. METHODS: We conducted a phase II study of decitabine in 14 men with progressive, metastatic prostate cancer recurrent after total androgen blockade and flutamide withdrawal. Decitabine was administered at a dose of 75 mg/m2/dose i.v. as a 1 hour infusion every 8 hours for three doses. Cycles of therapy were repeated every 5 to 8 weeks to allow for resolution of toxicity. RESULTS: Two of 12 patients evaluable for response had stable disease with a time to progression of more than 10 weeks. This activity was seen in 2 of 3 African-American patients. Toxicity was similar to previously reported experience. No significant changes in urinary concentrations of the angiogenic factor bFGF, a potential biomarker of tumor activity, were identified over time in 7 unselected patients with progressive disease. CONCLUSIONS: We conclude that decitabine is a well tolerated regimen with modest clinical activity against hormone-independent prostate cancer. Further investigations in patients of African-American origin may be warranted.
Asunto(s)
Antimetabolitos Antineoplásicos/uso terapéutico , Azacitidina/análogos & derivados , Biomarcadores de Tumor/sangre , Metilasas de Modificación del ADN/antagonistas & inhibidores , Inhibidores Enzimáticos/uso terapéutico , Factor 2 de Crecimiento de Fibroblastos/sangre , Neoplasias de la Próstata/tratamiento farmacológico , Anciano , Azacitidina/uso terapéutico , Decitabina , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Neoplasias de la Próstata/sangre , Resultado del TratamientoRESUMEN
African-American males have a higher incidence of prostate cancer than non-African-American males and an overall poorer prognosis. Environmental factors such as socioeconomic status and biological factors such as an increased frequency of androgen receptor mutation have been identified as causal. As androgen ablation therapy is ubiquitous in the treatment of metastatic prostate cancer, little information is available on clinical outcome independent of hormone therapy. Our experience at the Warren G. Magnusson Clinical Center, National Institutes of Health with the anticancer agent, suramin, offers the opportunity to study clinical outcome in patients treated with an agent whose tumoricidal activity is not dependent on androgen receptor function. Clinical outcome was examined retrospectively in 43 patients treated on a single suramin-based protocol and evaluated as a function of ethnic background. No significant difference in time to disease progression or survival was observed between African Americans (n = 4) and the other 39 patients. These findings are consistent with the hypothesis that therapies that work through mechanisms independent of the androgen receptor may result in similar outcomes across ethnic groups.
Asunto(s)
Antineoplásicos/uso terapéutico , Población Negra , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/etnología , Suramina/uso terapéutico , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/mortalidad , Neoplasias de la Próstata/secundario , Receptores Androgénicos , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del TratamientoAsunto(s)
Purgación de la Médula Ósea , Células Madre Neoplásicas/efectos de los fármacos , Oligonucleótidos Antisentido , Animales , Compartimento Celular , Proteínas de Fusión bcr-abl/biosíntesis , Proteínas de Fusión bcr-abl/genética , Genes myc , Humanos , Linfoma de Células B Grandes Difuso/patología , Lisosomas/metabolismo , Neoplasias/genética , Neoplasias/patología , Neoplasias/terapia , Oligonucleótidos Antisentido/farmacocinética , Oligonucleótidos Antisentido/toxicidad , ARN Mensajero/antagonistas & inhibidores , ARN Mensajero/metabolismo , ARN Neoplásico/antagonistas & inhibidores , ARN Neoplásico/metabolismo , Células Tumorales CultivadasRESUMEN
PURPOSE: To assess the efficacy and toxicity of suramin, hydrocortisone, leuprolide, and flutamide in previously untreated metastatic prostate cancer. PATIENTS AND METHODS: Patients with stage D2 and poor-prognosis stage D1 prostate cancer were given suramin on a pharmacokinetically derived dosing schedule to maintain suramin concentrations between 175 and 300 micrograms/mL. Additionally, all patients received flutamide 250 mg orally three times daily, initiated on day 1 and continued until disease progression; depot leuprolide 7.5 mg intramuscularly begun on day 5 and repeated every 4 weeks indefinitely; and replacement doses of hydrocortisone. RESULTS: Fifty patients were entered onto the study: 48 with stage D2 and two with stage D1 disease. The median age was 59 years (range, 42 to 79) and 31 patients had a Karnofsky performance status (KPS) of 100%. Forty-five patients had bone metastases and 25 had measurable soft tissue disease. Forty-one (82%) had severe disease. The overall response rate in 49 assessable patients was three complete responses (CRs) and 30 partial responses (PRs) for an overall response rate of 67%. Eighteen patients have died. The median survival time has not been reached, with a median potential follow-up duration of 44 months. Grade 3 to 4 toxicity was seen in 38% of patients and was predominantly hematologic and reversible. CONCLUSION: The high response rate and prolonged survival in a poor-prognosis group of patients with metastatic prostate cancer warrant a phase III randomized comparison of this regimen versus hormonal therapy alone. Toxicity was moderate and reversible.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/patología , Adulto , Anciano , Antineoplásicos Hormonales/administración & dosificación , Progresión de la Enfermedad , Esquema de Medicación , Flutamida/administración & dosificación , Humanos , Leuprolida/administración & dosificación , Masculino , Persona de Mediana Edad , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/inmunología , Suramina/administración & dosificación , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
BACKGROUND: A prospective Phase II clinical trial was conducted to assess the clinical activity of a pharmacokinetically guided suramin regimen in patients who had documented progression of metastatic prostate cancer after hydrocortisone plus antecedent or simultaneous withdrawal of flutamide. METHODS: Fifty-four patients whose disease had progressed after castration and flutamide administration were enrolled on this trial. The study was divided into two parts. Initially, 52 patients received hydrocortisone (30 mg/day) and for those patients receiving flutamide, at study entry (34 patients) flutamide was simultaneously discontinued. Forty-three patients whose disease progressed on hydrocortisone received suramin for 6-8 weeks. Six patients who progressed on hydrocortisone became ineligible for suramin due to clinical deterioration, four patients are still responding to hydrocortisone at more than 1 year, and one patient elected to postpone initiation of suramin. Suramin was given as intermittent infusions at fixed doses on days 1-5 and thereafter dosing was guided by adaptive control with feedback to maintain plasma suramin concentrations between 300-175 micrograms/ml. Antitumor activity was assessed by prostate specific antigen (PSA) decline and soft-tissue disease response. RESULTS: Ten patients (19%; 95% CI, 9.6%-32.5%) responded to hydrocortisone therapy with either a 50% or greater PSA decline for at least 4 weeks (9 patients) and/or a partial response of measurable soft-tissue disease (2 patients). Five of these patients (10%) demonstrated a 80% or greater PSA decline. All responders to hydrocortisone had simultaneous flutamide withdrawal, and had been receiving flutamide as part of initial combined androgen blockade. Seven of 37 evaluable patients (19%; 95% CI, 8.0%-35.2%) responded to suramin with a 50% or greater decline in PSA for 4 weeks or longer. One patient (3%) had a 80% or greater decline in PSA. There were no soft-tissue disease responses to suramin. The median time to progression was 1.9 months for hydrocortisone therapy and 2.6 months for suramin therapy. The median survival for all patients was 14.6 months. CONCLUSION: Suramin has antitumor activity in metastatic prostate carcinoma independent of the therapeutic effect of hydrocortisone administration or flutamide withdrawal. The role of prior flutamide withdrawal and hydrocortisone replacement should be taken into account in future studies of suramin.
Asunto(s)
Antineoplásicos/uso terapéutico , Flutamida/uso terapéutico , Hidrocortisona/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Suramina/uso terapéutico , Anciano , Antineoplásicos/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Antígeno Prostático Específico/análisis , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/mortalidad , Suramina/efectos adversos , Insuficiencia del TratamientoAsunto(s)
Andrógenos/agonistas , Flutamida/farmacología , Antígeno Prostático Específico/efectos de los fármacos , Neoplasias de la Próstata/inmunología , Receptores Androgénicos/efectos de los fármacos , Anciano , Flutamida/administración & dosificación , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Resultado del TratamientoRESUMEN
Direct interaction of oligodeoxynucleotides (ODNs) with proteins represents one of the nonantisense-mediated effects of ODNs. Phosphorothioate-capped ODNs have been shown to inhibit directly the in vitro kinase activity of the chronic myelogenous leukemia-associated protein-tyrosine kinase p210bcr-abl. In this study we have determined the efficacy of this aptameric ODN in a cellular system using the K562 chronic myelogenous leukemia-derived cell line. Significant effects upon cellular phosphotyrosine content, as well as cellular growth in soft agar, are observed. These effects are sequence specific and are not mediated through changes in p210bcr-abl protein levels. Additional ODNs are described that also reduce cellular phosphotyrosine levels and inhibit growth in soft agar but do not inhibit p210bcr-abl kinase activity in vitro.
Asunto(s)
Proteínas de Fusión bcr-abl/metabolismo , Oligonucleótidos Antisentido/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Secuencia de Bases , División Celular/efectos de los fármacos , Línea Celular , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva , Datos de Secuencia Molecular , Oligonucleótidos Antisentido/síntesis química , Fosfotirosina , Proteínas Tirosina Quinasas/metabolismo , Relación Estructura-Actividad , Células Tumorales Cultivadas , Tirosina/análogos & derivados , Tirosina/análisisRESUMEN
The use of suramin, a polysulfonated naphthylurea, in the treatment of advanced prostate cancer currently is being investigated. A 52-year-old man developed acute renal dysfunction after receiving nine doses of suramin. His suramin therapy was discontinued, but his serum creatinine level continued to rise to 10.8 mg/dl during the next 6 days. The patient was not rechallenged with suramin, and his renal function returned to baseline within the next 3 weeks. Future investigators of this drug should be aware of the possibility of such a reaction with parenteral administration.