RESUMO
PURPOSE: To evaluate the relationship between volume and vascularization of the periovulatory follicle and subfollicular area measured by three-dimensional power Doppler ultrasound (US), and ovulation and pregnancy in patients undergoing intrauterine insemination (IUI). METHODS: We studied 79 consecutive cycles of IUI on hCG administration day. We measured the periovulatory follicle and subfollicular area by means of three-dimensional power Doppler US. The stored volumes were processed with the VOCAL image processing software to calculate the volume of the follicle and the following vascular indices: vascularization index (VI), flow index (FI), and vascularization flow index (VFI). RESULTS: The follicular volume was higher in anovulatory cycles (7.7 ± 3.7 cubic centimeters (CC) versus 4.1 ± 2.0 CC; p < 0.001). There was no difference between the follicular volumes in cycles with or without subsequent pregnancy. The vascular indices of the follicle did not differ significantly between ovulatory and anovulatory cycles, and between cycles that did and did not achieve pregnancy. Periovulatory subfollicular VI and VFI were lower in women who became pregnant (VI: 2.9 ± 2.3% versus 5.6 ± 4.6%; p < 0.05, and VFI: 1.1 ± 0.8 versus 2.2 ± 2.2; p < 0.01). CONCLUSIONS: High values of follicular volume were associated with anovulatory cycles. Subfollicular VI and VFI might be used as markers of follicular quality and pregnancy predictors.
Assuntos
Imageamento Tridimensional , Infertilidade Feminina , Inseminação Artificial/métodos , Folículo Ovariano/diagnóstico por imagem , Ultrassonografia Doppler , Adulto , Feminino , Hormônio Foliculoestimulante/uso terapêutico , Hormônios/uso terapêutico , Humanos , Interpretação de Imagem Assistida por Computador , Infertilidade Feminina/tratamento farmacológico , Inseminação Artificial/fisiologia , Folículo Ovariano/irrigação sanguínea , Folículo Ovariano/fisiologia , Ovulação/fisiologia , Indução da Ovulação , Gravidez , Estudos ProspectivosRESUMO
The most common etiology of postpartum hemorrhage is uterine atony, although hematologic disorders may be present. A 36-year-old nulliparous woman underwent puerperal hysterectomy caused by uncontrolled postpartum hemorrhage. One day after discharge, she vomited in the emergency room a 24-cm long Ascaris lumbricoides. Infestation during gestation may cause hematologic disorders that could complicate pregnancy outcome.
Assuntos
Ascaríase/complicações , Ascaris lumbricoides , Histerectomia , Hemorragia Pós-Parto/cirurgia , Complicações Parasitárias na Gravidez , Adulto , Animais , Transtornos da Coagulação Sanguínea/parasitologia , Feminino , Humanos , Hemorragia Pós-Parto/parasitologia , Gravidez , Complicações Hematológicas na GravidezRESUMO
Therapy resistance represents a major clinical challenge in disseminated prostate cancer for which only palliative treatment is available. One phenotype of therapy-resistant tumors is the expression of somatic, gain-of-function mutations of the androgen receptor (AR). Such mutant receptors can use noncanonical endogenous ligands (e.g., estrogen) as agonists, thereby promoting recurrent tumor formation. Additionally, selected AR mutants are sensitized to the estrogenic endocrine-disrupting compound (EDC) bisphenol A, present in the environment. Herein, screening of additional EDCs revealed that multiple tumor-derived AR mutants (including T877A, H874Y, L701H, and V715M) are sensitized to activation by the pesticide 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE), thus indicating that this agent may impinge on AR signaling in cancer cells. Further investigation showed that DDE induced mutant AR recruitment to the prostate-specific antigen regulatory region, concomitant with an enhancement of target gene expression, and androgen-independent proliferation. By contrast, neither AR activation nor altered cellular proliferation was observed in cells expressing wild-type AR. Activation of signal transduction pathways was also observed based on rapid phosphorylation of mitogen-activated protein kinase (MAPK) and vasodilator-stimulated phosphoprotein, although only MAPK activation was associated with DDE-induced cellular proliferation. Functional analyses showed that both mutant AR and MAPK pathways contribute to the proliferative action of DDE, as evidenced through selective abrogation of each pathway. Together, these data show that exposure to environmentally relevant doses of EDCs can promote androgen-independent cellular proliferation in tumor cells expressing mutant AR and that DDE uses both mutant AR and MAPK pathways to exert its mitogenic activity.
Assuntos
Diclorodifenil Dicloroetileno/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação/genética , Neoplasias da Próstata/tratamento farmacológico , Receptores Androgênicos/metabolismo , Androgênios/farmacologia , Animais , Proliferação de Células , Chlorocebus aethiops , Imunoprecipitação da Cromatina , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Humanos , Immunoblotting , Rim/metabolismo , Rim/patologia , Luciferases/metabolismo , Masculino , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/patologia , Plasmídeos , Antígeno Prostático Específico/genética , Antígeno Prostático Específico/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Transporte Proteico/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Androgênicos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Transcrição Gênica/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
BACKGROUND: Cadmium is implicated in prostate carcinogenesis, but its oncogenic action remains unclear. OBJECTIVES: In this study we aimed to decipher changes in cell growth and the transcriptome in an immortalized human normal prostate epithelial cell line (NPrEC) following exposure to low-dose Cd. METHODS: Synchronized NPrEC cells were exposed to different doses of Cd and assayed for cell viability and cell-cycle progression. We investigated changes in transcriptome by global profiling and used Ingenuity Pathways Analysis software to develop propositions about functional connections among differentially expressed genes. A neutralizing antibody was used to negate the effect of Cd-induced up-regulation of tumor necrosis factor (TNF) in NPrEC cells. RESULTS: Exposure of NPrEC to 2.5 microM Cd enhanced cell viability and accelerated cell-cycle progression. Global expression profiling identified 48 genes that exhibited >or= 1.5-fold changes in expression after 4, 8, 16, and 32 hr of Cd treatment. Pathway analyses inferred a functional connection among 35 of these genes in one major network, with TNF as the most prominent node. Fourteen of the 35 genes are related to TNF, and 11 exhibited an average of >2-fold changes in gene expression. Real-time reverse transcriptase-polymerase chain reaction confirmed the up-regulation of 7 of the 11 genes (ADAM8, EDN1, IL8, IL24, IL13RA2, COX2/PTGS2, and SERPINB2) and uncovered a 28-fold transient increase in TNF expression in Cd-treated NPrEC cells. A TNF-neutralizing antibody effectively blocked Cd-induced elevations in the expression of these genes. CONCLUSIONS: Noncytotoxic, low-dose Cd has growth-promoting effects on NPrEC cells and induces transient overexpression of TNF, leading to up-regulation of genes with oncogenic and immunomodulation functions.
Assuntos
Cádmio/toxicidade , Células Epiteliais/efeitos dos fármacos , Perfilação da Expressão Gênica/métodos , Próstata/citologia , Anticorpos/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Humanos , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
PURPOSE: Interleukin-6 (IL-6), a proinflammatory cytokine the serum andtissue levels of which are elevated in prostate cancer patients, activates the androgen receptor (AR) in a ligand-independent and synergistic manner. Oncostatin M (OSM) is an IL-6 type cytokine that regulates the growth of prostate cancer cells in a paracrine fashion. The present study was designed to investigate the regulation of AR expression and function by OSM, as well as the efficacy of the nonsteroidal antiandrogens hydroxyflutamide and bicalutamide in the inhibition of AR-mediated signal transduction. EXPERIMENTAL DESIGN: Expression of the OSM receptor-beta in the prostate cancer cell lines LNCaP, PC-3, and DU-145 was investigated by reverse transcription-PCR. DU-145 and PC-3 cells were cotransfected with an androgen-responsive gene and AR cDNA. Reporter gene activity was measured after treatment with androgen and/or OSM in the absence or presence of antiandrogens or protein kinase inhibitors. AR expression after OSM treatment was assessed by Western blot. RESULTS: OSM receptor-beta expression was higher in DU-145 and PC-3 than in LNCaP cells. OSM caused ligand-independent activation of the AR in DU-145 cells, and the maximal activation was 62% of that induced by the synthetic androgen methyltrienolone. In the presence of OSM, hydroxyflutamide behaved as an AR agonist. Bicalutamide down-regulated AR activation caused by OSM only at a concentration of 1 microM. The inhibitor of the protein kinase A signaling pathway PKI and dn signal transducers and activators of transcription (STAT) 3 showed no effect on AR activation by OSM. The inhibitor of the MAPK pathway, PD 98059, caused only a minor down-regulation of OSM-induced reporter gene activity. OSM did not change AR expression in DU-145 cells transfected with AR cDNA. CONCLUSIONS: OSM is a member of the IL-6 family of cytokines, which causes ligand-independent activation of the AR without altering receptor expression. In contrast to AR activation by IL-6, nonsteroidal AR antagonists act as agonists in the presence of OSM. This may be attributable to recruitment of different intermediary signal transduction proteins by OSM and IL-6, respectively. The acquisition of agonistic properties of AR blockers in the presence of OSM might compromise use of these drugs in prostate cancer treatment.
Assuntos
Antagonistas de Androgênios/farmacologia , Antineoplásicos/farmacologia , Cloranfenicol/análogos & derivados , Flutamida/análogos & derivados , Inibidores do Crescimento/farmacologia , Interleucina-6/farmacologia , Peptídeos/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Receptores Androgênicos/metabolismo , Anilidas/farmacologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Cloranfenicol/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Primers do DNA/química , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Flutamida/farmacologia , Humanos , Masculino , Nitrilas , Oncostatina M , Neoplasias da Próstata/metabolismo , Receptores de Citocinas/metabolismo , Receptores de Oncostatina M , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Compostos de Tosil , Transfecção , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismoRESUMO
BACKGROUND: Our aim was to evaluate and compare lymph node involvement, as well as disease-free survival (DFS) and overall survival (OS), between infiltrating ductal carcinoma with (group 1) and without (group 2) intraductal carcinoma component in order to determine the prognostic value of the intraductal component. METHODS: Data from 389 cases of infiltrating ductal carcinoma of the breast were included in the study by means of reviewing medical charts and pathology slides. RESULTS: There was no statistically significant difference between both groups regarding node status. The 5-year DFS rate was 90.7% in group 1 and 81.8% in group 2 (p = 0.014), with a median follow-up of 73.2 months (95% CI 68.3-77.4). There was no statistically significant difference in 5-year OS between groups (98% group 1 vs. 93% group 2) with a median global survival of 134 months (95% CI 131-137). CONCLUSIONS: The presence of intraductal component in the infiltrating carcinoma seems to increase DFS and may be an independent and favorable prognostic factor for breast cancer.
Assuntos
Neoplasias da Mama/mortalidade , Carcinoma Ductal de Mama/mortalidade , Carcinoma Intraductal não Infiltrante/mortalidade , Linfonodos/patologia , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Gradação de Tumores , Prognóstico , Taxa de SobrevidaRESUMO
The androgen receptor (AR) is critical for disseminated prostate cancer proliferation and survival. AR activity is targeted either through prevention of ligand synthesis or through the use of antagonists that bind the COOH-terminal ligand-binding domain. Although initially effective, treatment fails due to restored AR activity in the presence of therapeutics. Thus, new means must be developed to target AR activity. The SWI/SNF chromatin remodeling complex is critical for AR transcriptional activity, and the BAF57 SWI/SNF subunit facilitates direct interaction with the receptor. Although selected SWI/SNF subunit expression is reduced in prostate cancer, we show that BAF57 is retained in human disease and is elevated in a subset of tumors. Functional analyses showed that BAF57 contributes uniquely to androgen-mediated stimulation of transcription without compromising the effectiveness of AR antagonists. Subsequent studies revealed that BAF57 is recruited to the AR DNA-binding domain/hinge region, which occurs concomitant with receptor activation. These data provided the basis for a novel inhibitor derived from BAF57 [BAF57 inhibitory peptide (BIPep)], which blocked AR residence on chromatin and resultant AR-dependent gene activation. Importantly, BIPep expression was sufficient to inhibit androgen-dependent prostate cancer cell proliferation in AR-positive cells. In summary, these data identify blockade of AR-BAF57 interaction as a novel means to target agonist-induced AR function in prostate cancer, and provide the first evidence that abrogation of SWI/SNF function can be developed as a point of therapeutic intervention in prostate cancer.
Assuntos
Proliferação de Células , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fragmentos de Peptídeos/farmacologia , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Antagonistas de Receptores de Andrógenos , Animais , Cromatina/metabolismo , Imunoprecipitação da Cromatina , Proteínas Cromossômicas não Histona/antagonistas & inibidores , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Humanos , Imunização , Immunoblotting , Técnicas Imunoenzimáticas , Masculino , Fragmentos de Peptídeos/imunologia , Regiões Promotoras Genéticas/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Subunidades Proteicas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Coelhos , Receptores Androgênicos/genética , Elementos de Resposta , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica , Ativação TranscricionalRESUMO
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) holds great potential as an anticancer drug, since it induces selective cell death in cancer cells but not in normal ones. However, cancer cells often acquire resistance to TRAIL, which hinders its clinical efficacy. We previously demonstrated that progesterone triggers apoptosis in human ovarian cancer (OCa) cells. In the present study, we evaluated the prospect of utilizing progestins in combination with TRAIL to enhance cell death in TRAIL-sensitive (OVCA 420, OVCA 429, and OVCA 433) and -resistant (OVCA 432) OCa cell lines. TRAIL sensitivity (60-80% cell kill) bore no correlation with expression of the TRAIL receptors (DR4, DR5) or their decoys (DcR1 and DcR2), but was associated with activation of caspase-8 and -3, and downregulation of the long isoform of FLICE-like inhibitory protein (c-FLIP(L)), an anti-apoptosis mediator. Small interfering RNA-mediated knockdown of c-FLIP(L) expression restored TRAIL sensitivity in OVCA 432 cells. Induction of c-FLIP(L) overexpression increased TRAIL resistance in TRAIL-sensitive lines. Thus, persistent high level of c-FLIP(L) expression likely mediates TRAIL resistance in OCa cells. Treatment of OCa cells with progesterone enhanced TRAIL-induced cell death (>85%), but only in TRAIL-sensitive cell lines. Combined treatment with two progestins was superior to single progestin treatment, with progesterone plus medroxyprogesterone acetate (MPA) achieving over 85% cell kill in both TRAIL-sensitive and -resistant OCa cell lines. Significantly, unlike TRAIL, progestin-induced cell death did not involve c-FLIP(L) downregulation. Hence, combined progestin regimens, with or without TRAIL, may serve as an effective therapy for OCa by circumventing the anti-apoptotic action of c-FLIP(L).
Assuntos
Apoptose , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/metabolismo , Neoplasias Ovarianas/patologia , Progesterona/farmacologia , Progestinas/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Caspases/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Ativação Enzimática , Feminino , Proteínas Ligadas por GPI , Humanos , Acetato de Medroxiprogesterona/farmacologia , Noretindrona/análogos & derivados , Noretindrona/farmacologia , Acetato de Noretindrona , Neoplasias Ovarianas/metabolismo , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Membro 10c de Receptores do Fator de Necrose Tumoral , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Receptores Chamariz do Fator de Necrose Tumoral/metabolismoRESUMO
INTRODUCTION: Interleukin-6 (IL-6) is a pleiotropic regulator of prostate cancer cell growth. Oncostatin M (OSM), an IL-6-type cytokine, affects the growth of prostate cancers in a paracrine and autocrine manner. In order to understand better the mechanisms controlling proliferation and intracellular signaling by these cytokines in advanced prostate carcinoma, we performed studies in 22Rv1 cells derived from the relapsed xenograft CWR22R. METHODS: Expression of IL-6 and OSM receptors (OSMR-beta) and elements of signal transduction pathways in 22Rv1 cells were investigated by RT-PCR. Proliferation was assessed by cell counting after treatment with either IL-6 or OSM. IL-6 secretion was measured in conditioned medium from 22Rv1 cells by ELISA. Expression and phosphorylation status of signal transducers and activators of transcription factor (STAT) 3, mitogen-activated protein kinases (MAPK) p44/p42 and p38, and protein kinase B (Akt) was investigated by Western blot. RESULTS: 22Rv1 cells express both subunits of the IL-6 receptor (gp80 and gp130) and leukemia inhibitory factor receptor-beta (LIFR-beta) but not OSMR-beta. Their proliferation was stimulated by IL-6 or OSM and the maximal effect was observed at a concentration of 10 ng/ml of either cytokine. Interestingly, neither IL-6 nor OSM induced phosphorylation of STAT3. OSM modestly increased the phosphorylation of p38 and both cytokines exerted an effect on Akt phosphorylation. CONCLUSIONS: IL-6 and OSM stimulate proliferation of 22Rv1 cells, at least in part through activation of the phosphatidylinositol 3-kinase (PI 3-K) signaling pathway. Our data provide additional evidence for the growth-stimulatory role of IL-6 and related cytokines in advanced prostate cancer and may serve as a basis for the development of novel experimental therapies.
Assuntos
Interleucina-6/fisiologia , Peptídeos/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Neoplasias da Próstata/fisiopatologia , Proteínas Quinases p38 Ativadas por Mitógeno/fisiologia , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Masculino , Oncostatina M , Transdução de Sinais/fisiologiaRESUMO
Progression of human prostate cancer toward therapy resistance occurs in the presence of wild-type or mutated androgen receptors (ARs) that, in some cases, exhibit aberrant activation by various steroid hormones and anti-androgens. The AR associates with a number of co-activators that possess histone acetylase activity and act as bridging molecules to components of the transcription initiation complex. In previous reports, it was shown that the transcriptional co-activator CREB (cAMP response element-binding protein)-binding protein (CBP) enhances AR activity in a ligand-dependent manner. In the present study, we have investigated whether CBP modifies antagonist/agonist balance of the nonsteroidal anti-androgens hydroxyflutamide and bicalutamide. In prostate cancer DU-145 cells, which were transiently transfected with CBP cDNA, hydroxyflutamide enhanced AR activity to a greater extent than bicalutamide in the presence of either wild-type or the mutated AR 730 val-->met. In two sublines of LNCaP cells that contain the mutated AR 877 thr-->ala and overexpressed CBP, increase in AR activity was observed after treatment with hydroxyflutamide but not with bicalutamide. Anti-androgens did not influence AR expression in cells transfected with CBP cDNA, as judged by Western blot analysis. Endogenous CBP protein was detected by Western blot in nuclear extracts from the three prostate cancer cell lines, LNCaP, PC-3, and DU-145, all derived from therapy-resistant prostate cancer. In addition, CBP was expressed in both basal and secretory cells of benign prostate epithelium, high-grade prostate intraepithelial neoplasia, and prostate cancer clinical specimens, as evidenced by immunohistochemical staining. Taken together, our findings demonstrate the selective enhancement of agonistic action of the anti-androgen hydroxyflutamide by the transcriptional co-activator CBP, which is a new, potentially relevant mechanism contributing to the acquisition of therapy resistance in prostate cancer.
Assuntos
Antagonistas de Androgênios/farmacologia , Androgênios/farmacologia , Carcinoma/metabolismo , Proteínas Nucleares/biossíntese , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Transativadores/biossíntese , Proteína de Ligação a CREB , Carcinoma/patologia , Humanos , Metástase Linfática , Masculino , Proteínas Nucleares/genética , Hiperplasia Prostática/metabolismo , Hiperplasia Prostática/patologia , Neoplasias da Próstata/patologia , Receptores Androgênicos/efeitos dos fármacos , Transativadores/genética , Ativação Transcricional/efeitos dos fármacos , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
Interleukin-6 (IL-6) is a multifunctional cytokine that activates the signaling pathways of Janus kinases-signal transducers and activators of transcription (STAT) and/or mitogen-activated protein kinases (MAPK) in various tumors. Thus, it modulates cell growth and apoptosis. IL-6 levels are elevated in tissues and sera from prostate cancer patients and IL-6 receptor expression has been detected in prostate cancer cell lines and clinical specimens. Continuous exposure of prostate cancer cells to IL-6 might alter their responsiveness to this cytokine. To gain more insight into the function of IL-6 in prostate carcinoma, we have inoculated LNCaP-IL-6+ cells, generated after prolonged treatment with IL-6, into nude mice (total n = 16, two independent experiments). Controls included animals bearing LNCaP-IL-6- cells, passaged at the same time as LNCaP-IL-6+ cells without supplementation of IL-6. LNCaP-IL-6+ tumor volumes were larger than those of their counterparts at all time points. There were no signs of cachexia in any of the experimental animals and all mice were free of metastases. To better understand the mechanisms responsible for accelerated growth of LNCaP-IL-6+ tumors, we have investigated the expression of cell-cycle regulatory molecules by Western blot analysis. The levels of cyclin-dependent kinase 2 were elevated in LNCaP-IL-6+ cells. There was a strong down-regulation of cyclins D1 and E in the LNCaP-IL-6+ subline. The cell-cycle inhibitor p27 was expressed at a low level in LNCaP-IL-6+ cells and could not be up-regulated by addition of IL-6. Most notably, LNCaP-IL-6+ cells exhibited a reduced expression of the hypophosphorylated form of the retinoblastoma protein (pRb). Accelerated tumor growth in our model system was also associated with alterations in IL-6-signaling pathways. The ability of IL-6 to induce tyrosine phosphorylation of STAT3 was abolished in the LNCaP-IL-6+ subline. In contrast, the levels of the MAPK extracellular signal-regulated kinases 1/2 increased in cells generated after long-term IL-6 treatment. The inhibitor of MAPK kinase PD 98059 retarded the proliferation of LNCaP-IL-6+ but not that of control cells. In summary, we show in the present study that chronic exposure of prostate cancer cells to IL-6 facilitates tumor growth in vivo by abolishment of the growth control by pRb and activation of the MAPK signaling pathway. These findings could be relevant to understand the role of IL-6 in prostate cancer progression.
Assuntos
Regulação Neoplásica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/genética , Genes do Retinoblastoma , Interleucina-6/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Neoplasias da Próstata/patologia , Proteína do Retinoblastoma/genética , Animais , Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Regulação Neoplásica da Expressão Gênica/imunologia , Genes do Retinoblastoma/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/imunologia , Masculino , Camundongos , Camundongos Nus , Transplante HeterólogoRESUMO
BACKGROUND: Intermittent androgen ablation is a palliative treatment option for advanced prostate cancer which is associated with less side effects, improved quality of life of patients, and reduced costs. Regulation of growth and survival of prostate cancer cells during intermittent androgen withdrawal has not been studied in appropriate models yet. METHODS: Two cycles of androgen withdrawal and supplementation were performed in human prostate cancer cells LNCaP in vitro. Proliferation of prostate cancer cell sublines established after intermittent androgen withdrawal was assessed in the absence or presence of epidermal growth factor (EGF) by protein determination. Cell cycle was analyzed with a flow cytometer. EGF was measured in the supernatants of LNCaP sublines with a commercial ELISA. EGF receptor mRNA and protein were determined by real-time PCR and Western blot, respectively. RESULTS: Basal proliferation rate of all newly generated LNCaP sublines increased over that of the parental LNCaP cell line. The highest stimulation of proliferation by exogenous EGF was observed in parental LNCaP cells. In each LNCaP derivative established during intermittent androgen withdrawal, the percentage of cells in the S phase of cell cycle was higher than that in parental LNCaP cells. EGF levels did not increase during intermittent androgen ablation. The expression of EGF receptor protein decreased following each cycle of androgen ablation and increased subsequently after androgen supplementation. EGF receptor (EGFR) mRNA was regulated in a similar manner in LNCaP derivatives established during the second cycle of intermittent withdrawal. CONCLUSIONS: Changes in the expression of the EGF receptor occur during intermittent androgen ablation but they cannot be solely responsible for increased basal proliferation. Alternatively, other ligands and receptors of the EGF system may become overexpressed during prolonged withdrawal and supplementation of androgenic hormones in prostate cancer therapy.