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1.
Commun Biol ; 4(1): 381, 2021 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-33753863

RESUMEN

Therapies for lethal castration-resistant prostate cancer (CRPC) are an unmet medical need. One mechanism underlying CRPC and resistance to hormonal therapies is the expression of constitutively active splice variant(s) of androgen receptor (AR-Vs) that lack its C-terminus ligand-binding domain. Transcriptional activities of AR-Vs and full-length AR reside in its N-terminal domain (NTD). Ralaniten is the only drug proven to bind AR NTD, and it showed promise of efficacy in Phase 1 trials. The peptidyl-prolyl isomerase Pin1 is frequently overexpressed in prostate cancer. Here we show that Pin1 interacted with AR NTD. The inhibition of Pin1 expression or its activity selectively reduced the transcriptional activities of full-length AR and AR-V7. Combination of Pin1 inhibitor with ralaniten promoted cell cycle arrest and had improved antitumor activity against CRPC xenografts in vivo compared to individual monotherapies. These findings support the rationale for therapy that combines a Pin1 inhibitor with ralaniten for treating CRPC.

2.
J Nat Prod ; 2020 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-33124806

RESUMEN

Synthetic analogues of the marine natural product sintokamides have been prepared in order to investigate the structure-activity relationships for the androgen receptor N-terminal domain (AR NTD) antagonist activity of the sintokamide scaffold. An in vitro LNCaP cell-based transcriptional activity assay with an androgen-driven luciferase (Luc) reporter was used to monitor the potency of analogues. The data have shown that the chlorine atoms on the leucine side chains are essential for potent activity. Analogues missing the nonchlorinated methyl groups of the leucine side chains (C-1 and C-17) are just as active and in some cases more active than the natural products. Analogues with the natural R configuration at C-10 and the unnatural R configuration at C-4 are most potent. Replacing the natural propionamide N-terminus cap with the more sterically hindered pivaloylamide N-terminus cap leads to enhanced potency. The tetramic acid fragment and the methyl ether on the tetramic acid fragment are essential for activity. The SAR optimized analogue 76 is more selective, easier to synthesize, more potent, and presumed to be more resistant to proteolysis than the natural sintokamides.

3.
Cancers (Basel) ; 12(7)2020 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-32708219

RESUMEN

Blocking androgen receptor (AR) transcriptional activity by androgen deprivation therapy (ADT) improves the response to radiotherapy for intermediate and high risk prostate cancer. Unfortunately, ADT, antiandrogens, and abiraterone increase expression of constitutively active splice variants of AR (AR-Vs) which regulate DNA damage repair leading to resistance to radiotherapy. Here we investigate whether blocking the transcriptional activities of full-length AR and AR-Vs with ralaniten leads to enhanced sensitivity to radiotherapy. Combination therapies using ralaniten with ionizing radiation were evaluated for effects on proliferation, colony formation, cell cycle, DNA damage, and Western blot analyses in human prostate cancer cells that express both full-length AR and AR-Vs. Ralaniten and a potent next-generation analog (EPI-7170) decreased expression of DNA repair genes whereas enzalutamide had no effect. FACS analysis revealed a dose-dependent decrease of BrdU incorporation with increased accumulation of γH2AX with a combination of ionizing radiation with ralaniten. An additive inhibitory effect on proliferation of enzalutamide-resistant cells was achieved with a combination of ralaniten compounds with ionizing radiation. Ralaniten and EPI-7170 sensitized prostate cancer cells that express full-length AR and AR-Vs to radiotherapy whereas enzalutamide had no added benefit.

4.
ACS Pharmacol Transl Sci ; 2(6): 453-467, 2019 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-32259077

RESUMEN

Inhibition of the androgen receptor (AR) is the mainstay treatment for advanced prostate cancer. Ralaniten (formally EPI-002) prevents AR transcriptional activity by binding to its N-terminal domain (NTD) which is essential for transcriptional activity. Ralaniten acetate (EPI-506) the triacetate pro-drug of ralaniten, remains the only AR-NTD inhibitor to have entered clinical trials (NCT02606123). While well tolerated, the trial was ultimately terminated due to poor pharmacokinetic properties and resulting pill burden. Here we discovered that ralaniten was glucuronidated which resulted in decreased potency. Long-term treatment of prostate cancer cells with ralaniten results in upregulation of UGT2B enzymes with concomitant loss of potency. This has proven to be a useful model with which to facilitate the development of more potent second-generation AR-NTD inhibitors. Glucuronidated metabolites of ralaniten were also detected in the serum of patients in Phase 1 clinical trials. Therefore, we tested an analogue of ralaniten (EPI-045) which was resistant to glucuronidation and demonstrated superiority to ralaniten in our resistant model. These data support that analogues of ralaniten designed to mitigate glucuronidation may optimize clinical responses to AR-NTD inhibitors.

5.
PLoS One ; 12(3): e0174134, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28306720

RESUMEN

Androgen receptor (AR) is a member of the steroid receptor family and a therapeutic target for all stages of prostate cancer. AR is activated by ligand binding within its C-terminus ligand-binding domain (LBD). Here we show that overexpression of the AR NTD to generate decoy molecules inhibited both the growth and progression of prostate cancer in castrated hosts. Specifically, it was shown that lentivirus delivery of decoys delayed hormonal progression in castrated hosts as indicated by increased doubling time of tumor volume, prolonged time to achieve pre-castrate levels of serum prostate-specific antigen (PSA) and PSA nadir. These clinical parameters are indicative of delayed hormonal progression and improved therapeutic response and prognosis. Decoys reduced the expression of androgen-regulated genes that correlated with reduced in situ interaction of the AR with androgen response elements. Decoys did not reduce levels of AR protein or prevent nuclear localization of the AR. Nor did decoys interact directly with the AR. Thus decoys did not inhibit AR transactivation by a dominant negative mechanism. This work provides evidence that the AR NTD plays an important role in the hormonal progression of prostate cancer and supports the development of AR antagonists that target the AR NTD.


Asunto(s)
Orquiectomía , Neoplasias de la Próstata/patología , Receptores Androgénicos/efectos de los fármacos , Animales , Progresión de la Enfermedad , Humanos , Lentivirus/genética , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores Androgénicos/metabolismo , Recurrencia
6.
J Biol Chem ; 291(42): 22231-22243, 2016 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-27576691

RESUMEN

Androgen receptor (AR) is a validated drug target for all stages of prostate cancer including metastatic castration-resistant prostate cancer (CRPC). All current hormone therapies for CRPC target the C-terminal ligand-binding domain of AR and ultimately all fail with resumed AR transcriptional activity. Within the AR N-terminal domain (NTD) is activation function-1 (AF-1) that is essential for AR transcriptional activity. Inhibitors of AR AF-1 would potentially block most AR mechanisms of resistance including constitutively active AR splice variants that lack the ligand-binding domain. Here we provide evidence that sintokamide A (SINT1) binds AR AF-1 region to specifically inhibit transactivation of AR NTD. Consistent with SINT1 targeting AR AF-1, it attenuated transcriptional activities of both full-length AR and constitutively active AR splice variants, which correlated with inhibition of growth of enzalutamide-resistant prostate cancer cells expressing AR splice variants. In vivo, SINT1 caused regression of CRPC xenografts and reduced expression of prostate-specific antigen, a gene transcriptionally regulated by AR. Inhibition of AR activity by SINT1 was additive to EPI-002, a known AR AF-1 inhibitor that is in clinical trials (NCT02606123). This implies that SINT1 binds to a site on AF-1 that is unique from EPI. Consistent with this suggestion, these two compounds showed differences in blocking AR interaction with STAT3. This work provides evidence that the intrinsically disordered NTD of AR is druggable and that SINT1 analogs may provide a novel scaffold for drug development for the treatment of prostate cancer or other diseases of the AR axis.


Asunto(s)
Antagonistas de Receptores Androgénicos/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Proteínas de Neoplasias , Neoplasias de la Próstata , Pirrolidinonas/farmacología , Receptores Androgénicos/biosíntesis , Activación Transcripcional/efectos de los fármacos , Animales , Línea Celular Tumoral , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/metabolismo , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/metabolismo , Dominios Proteicos , Pirrolidinonas/farmacocinética , Factor de Transcripción STAT3/metabolismo
7.
JCI Insight ; 1(11)2016 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-27525313

RESUMEN

Constitutively active splice variants of androgen receptor (AR-Vs) lacking ligand-binding domain (LBD) are a mechanism of resistance to androgen receptor LBD-targeted (AR LBD-targeted) therapies for metastatic castration-resistant prostate cancer (CRPC). There is a strong unmet clinical need to identify prostate cancer patients with AR-V-positive lesions to determine whether they will benefit from further AR LBD-targeting therapies or should receive taxanes or investigational drugs like EPI-506 or galeterone. Both EPI-506 (NCT02606123) and galeterone (NCT02438007) are in clinical trials and are proposed to have efficacy against lesions that are positive for AR-Vs. AR activation function-1 (AF-1) is common to the N-terminal domains of full-length AR and AR-Vs. Here, we provide proof of concept for developing imaging compounds that directly bind AR AF-1 to detect both AR-Vs and full-length AR. 123I-EPI-002 had specific binding to AR AF-1, which enabled direct visualization of CRPC xenografts that express full-length AR and AR-Vs. Our findings highlight the potential of 123I-EPI-002 as an imaging agent for the detection of full-length AR and AR-Vs in CRPC.

8.
Clin Cancer Res ; 22(17): 4466-77, 2016 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-27140928

RESUMEN

PURPOSE: Persistent androgen receptor (AR) transcriptional activity is clinically evident in castration-resistant prostate cancer (CRPC). Therefore, AR remains as a viable therapeutic target for CRPC. All current hormonal therapies target the C-terminus ligand-binding domain (LBD) of AR. By using EPI to target AR activation function-1 (AF-1), in the N-terminal domain that is essential for AR transactivation, we evaluate the ability of EPI to overcome several clinically relevant AR-related mechanisms of resistance. EXPERIMENTAL DESIGN: To study the effect of EPI on AR transcriptional activity against overexpressed coactivators, such as SRC1-3 and p300, luciferase reporter assays were performed using LNCaP cells. AR-negative COS-1 cells were employed for reporter assays to examine whether the length of polyglutamine tract affects inhibition by EPI. The effect of EPI on constitutively active AR splice variants was studied in LNCaP95 cells, which express AR-V7 variant. To evaluate the effect of EPI on the proliferation of LNCaP95 cells, we performed in vitro BrdUrd incorporation assay and in vivo studies using xenografts in mice. RESULTS: EPI effectively overcame several molecular alterations underlying aberrant AR activity, including overexpressed coactivators, AR gain-of-function mutations, and constitutively active AR-V7. EPI inhibited AR transcriptional activity regardless of the length of polyglutamine tract. Importantly, EPI significantly inhibited the in vitro and in vivo proliferation of LNCaP95 prostate cancer cells, which are androgen independent and enzalutamide resistant. CONCLUSIONS: These findings support EPI as a promising therapeutic agent to treat CRPC, particularly against tumors driven by constitutively active AR splice variants that are resistant to LBD-targeting drugs. Clin Cancer Res; 22(17); 4466-77. ©2016 AACRSee related commentary by Sharp et al., p. 4280.


Asunto(s)
Antagonistas de Receptores Androgénicos/farmacología , Compuestos de Bencidrilo/farmacología , Clorhidrinas/farmacología , Resistencia a Antineoplásicos , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Receptores Androgénicos/metabolismo , Animales , Apoptosis/efectos de los fármacos , Células COS , Línea Celular Tumoral , Chlorocebus aethiops , Modelos Animales de Enfermedad , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Masculino , Ratones , Mutación , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Unión Proteica , Empalme del ARN , Receptores Androgénicos/genética , Transducción de Señal/efectos de los fármacos , Activación Transcripcional , Ensayos Antitumor por Modelo de Xenoinjerto
9.
Clin Cancer Res ; 22(11): 2744-54, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-26712685

RESUMEN

PURPOSE: The PI3K/Akt/mTOR pathway is activated in most castration-resistant prostate cancers (CRPC). Transcriptionally active androgen receptor (AR) plays a role in the majority of CRPCs. Therefore, cotargeting full-length (FL) AR and PI3K/Akt/mTOR signaling has been proposed as a possible, more effective therapeutic approach for CRPC. However, truncated AR-splice variants (AR-V) that are constitutively active and dominant over FL-AR are associated with tumor progression and resistance mechanisms in CRPC. It is currently unknown how blocking the PI3K/Akt/mTOR pathway impacts prostate cancer driven by AR-Vs. Here, we evaluated the efficacy and mechanism of combination therapy to block mTOR activity together with EPI-002, an AR N-terminal domain (NTD) antagonist that blocks the transcriptional activities of FL-AR and AR-Vs in models of CRPC. EXPERIMENTAL DESIGN: To determine the functional roles of FL-AR, AR-Vs, and PI3K/Akt/mTOR pathways, we employed EPI-002 or enzalutamide and BEZ235 (low dose) or everolimus in human prostate cancer cells that express FL-AR or FL-AR and AR-Vs (LNCaP95). Gene expression and efficacy were examined in vitro and in vivo RESULTS: EPI-002 had antitumor activity in enzalutamide-resistant LNCaP95 cells that was associated with decreased expression of AR-V target genes (e.g., UBE2C). Inhibition of mTOR provided additional blockade of UBE2C expression. A combination of EPI-002 and BEZ235 decreased the growth of LNCaP95 cells in vitro and in vivo CONCLUSIONS: Cotargeting mTOR and AR-NTD to block transcriptional activities of FL-AR and AR-Vs provided maximum antitumor efficacy in PTEN-null, enzalutamide-resistant CRPC. Clin Cancer Res; 22(11); 2744-54. ©2015 AACR.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Compuestos de Bencidrilo/farmacología , Glicerol/análogos & derivados , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Receptores Androgénicos/genética , Empalme Alternativo , Animales , Antineoplásicos Hormonales/farmacología , Antineoplásicos Hormonales/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Sinergismo Farmacológico , Everolimus/administración & dosificación , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glicerol/farmacología , Imidazoles/administración & dosificación , Masculino , Ratones Endogámicos NOD , Ratones SCID , Feniltiohidantoína/administración & dosificación , Feniltiohidantoína/análogos & derivados , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Quinolinas/administración & dosificación , Receptores Androgénicos/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
10.
PLoS One ; 9(9): e107991, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25268119

RESUMEN

Androgen ablation therapy causes a temporary reduction in tumor burden in patients with advanced prostate cancer. Unfortunately the malignancy will return to form lethal castration-recurrent prostate cancer (CRPC). The androgen receptor (AR) remains transcriptionally active in CRPC in spite of castrate levels of androgens in the blood. AR transcriptional activity resides in its N-terminal domain (NTD). Possible mechanisms of continued AR transcriptional activity may include, at least in part, expression of constitutively active splice variants of AR that lack the C-terminal ligand-binding domain (LBD). Current therapies that target the AR LBD, would not be effective against these AR variants. Currently no drugs are clinically available that target the AR NTD which should be effective against these AR variants as well as full-length AR. Niphatenones were originally isolated and identified in active extracts from Niphates digitalis marine sponge. Here we begin to characterize the mechanism of niphatenones in blocking AR transcriptional activity. Both enantiomers had similar IC50 values of 6 µM for inhibiting the full-length AR in a functional transcriptional assay. However, (S)-niphatenone had significantly better activity against the AR NTD compared to (R)-niphatenone. Consistent with niphatenones binding to and inhibiting transactivation of AR NTD, niphatenones inhibited AR splice variant. Niphatenone did not affect the transcriptional activity of the related progesterone receptor, but slightly decreased glucocorticoid receptor (GR) activity and covalently bound to GR activation function-1 (AF-1) region. Niphatenone blocked N/C interactions of AR without altering either AR protein levels or its intracellular localization in response to androgen. Alkylation with glutathione suggests that niphatenones are not a feasible scaffold for further drug development.


Asunto(s)
Antagonistas de Receptores Androgénicos/farmacología , Antineoplásicos Hormonales/farmacología , Éteres de Glicerilo/farmacología , Línea Celular Tumoral , Humanos , Concentración 50 Inhibidora , Masculino , Metribolona/farmacología , Neoplasias de la Próstata/tratamiento farmacológico , Estructura Terciaria de Proteína , Receptores Androgénicos/química , Receptores Androgénicos/fisiología , Estereoisomerismo , Activación Transcripcional/efectos de los fármacos
11.
J Clin Invest ; 123(7): 2948-60, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23722902

RESUMEN

Hormone therapies for advanced prostate cancer target the androgen receptor (AR) ligand-binding domain (LBD), but these ultimately fail and the disease progresses to lethal castration-resistant prostate cancer (CRPC). The mechanisms that drive CRPC are incompletely understood, but may involve constitutively active AR splice variants that lack the LBD. The AR N-terminal domain (NTD) is essential for AR activity, but targeting this domain with small-molecule inhibitors is complicated by its intrinsic disorder. Here we investigated EPI-001, a small-molecule antagonist of AR NTD that inhibits protein-protein interactions necessary for AR transcriptional activity. We found that EPI analogs covalently bound the NTD to block transcriptional activity of AR and its splice variants and reduced the growth of CRPC xenografts. These findings suggest that the development of small-molecule inhibitors that bind covalently to intrinsically disordered proteins is a promising strategy for development of specific and effective anticancer agents.


Asunto(s)
Antagonistas de Receptores Androgénicos/farmacología , Antineoplásicos Hormonales/farmacología , Compuestos de Bencidrilo/farmacología , Clorhidrinas/farmacología , Neoplasias de la Próstata/tratamiento farmacológico , Receptores Androgénicos/metabolismo , Antagonistas de Receptores Androgénicos/química , Animales , Antineoplásicos Hormonales/química , Compuestos de Bencidrilo/química , Células COS , Proliferación Celular/efectos de los fármacos , Chlorocebus aethiops , Clorhidrinas/química , Química Clic , Expresión Génica , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Genes Reporteros , Humanos , Luciferasas/biosíntesis , Luciferasas/genética , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Orquiectomía , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Unión Proteica , Estructura Terciaria de Proteína , Receptores Androgénicos/química , Receptores Androgénicos/genética , Estereoisomerismo , Activación Transcripcional/efectos de los fármacos , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto
12.
Mol Cancer Ther ; 12(5): 621-31, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23443807

RESUMEN

Androgen receptor is a ligand-activated transcription factor and a validated drug target for all stages of prostate cancer. Antiandrogens compete with physiologic ligands for androgen receptor ligand-binding domain (LBD). High-throughput screening of a marine natural product library for small molecules that inhibit androgen receptor transcriptional activity yielded the furanoditerpenoid spongia-13(16),-14-dien-19-oic acid, designated terpene 1 (T1). Characterization of T1 and the structurally related semisynthetic analogues (T2 and T3) revealed that these diterpenoids have antiandrogen properties that include inhibition of both androgen-dependent proliferation and androgen receptor transcriptional activity by a mechanism that involved competing with androgen for androgen receptor LBD and blocking essential N/C interactions required for androgen-induced androgen receptor transcriptional activity. Structure-activity relationship analyses revealed some chemical features of T1 that are associated with activity and yielded T3 as the most potent analogue. In vivo, T3 significantly reduced the weight of seminal vesicles, which are an androgen-dependent tissue, thereby confirming the on-target activity of T3. The ability to create analogues of diterpenoids that have varying antiandrogen activity represents a novel class of chemical compounds for the analysis of androgen receptor ligand-binding properties and therapeutic development.


Asunto(s)
Antagonistas de Receptores Androgénicos/farmacología , Diterpenos/farmacología , Receptores Androgénicos/metabolismo , Antagonistas de Receptores Androgénicos/química , Andrógenos/metabolismo , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Diterpenos/química , Relación Dosis-Respuesta a Droga , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Masculino , Ratones , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Receptores Androgénicos/química , Transcripción Genética
13.
J Med Chem ; 55(1): 503-14, 2012 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-22148427

RESUMEN

Extracts of the marine sponge Niphates digitalis collected in Dominica showed strong activity in a cell-based assay designed to detect antagonists of the androgen receptor (AR) that could act as lead compounds for the development of a new class of drugs to treat castration recurrent prostate cancer (CRPC). Assay-guided fractionation showed that niphatenones A (3) and B (4), two new glycerol ether lipids, were the active components of the extracts. The structures of 3 and 4 were elucidated by analysis of NMR and MS data and confimed via total synthesis. Biological evaluation of synthetic analogues of the niphatenones has shown that the enantiomers 7 and 8 are more potent than the natural products in the screening assay and defined preliminary SAR for the new AR antagonist pharmacophore, including the finding that the Michael acceptor enone functionality is not required for activity. Niphatenone B (4) and its enantiomer 8 blocked androgen-induced proliferation of LNCaP prostate cancer cells but had no effect on the proliferation of PC3 prostate cancer cells that do not express functional AR, consistent with activity as AR antagonists. Use of the propargyl ether 44 and Click chemistry showed that niphatenone B binds covalently to the activation function-1 (AF1) region of the AR N-terminus domain (NTD).


Asunto(s)
Antineoplásicos/química , Éteres de Glicerilo/química , Poríferos/química , Neoplasias de la Próstata/genética , Receptores Androgénicos/genética , Animales , Antineoplásicos/síntesis química , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Éteres de Glicerilo/síntesis química , Éteres de Glicerilo/aislamiento & purificación , Éteres de Glicerilo/farmacología , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Conformación Molecular , Neoplasias de la Próstata/tratamiento farmacológico , Estereoisomerismo , Relación Estructura-Actividad , Transcripción Genética/efectos de los fármacos
14.
Cancer Cell ; 17(6): 535-46, 2010 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-20541699

RESUMEN

Castration-recurrent prostate cancer (CRPC) is suspected to depend on androgen receptor (AR). The AF-1 region in the amino-terminal domain (NTD) of AR contains most, if not all, of the transcriptional activity. Here we identify EPI-001, a small molecule that blocked transactivation of the NTD and was specific for inhibition of AR without attenuating transcriptional activities of related steroid receptors. EPI-001 interacted with the AF-1 region, inhibited protein-protein interactions with AR, and reduced AR interaction with androgen-response elements on target genes. Importantly, EPI-001 blocked androgen-induced proliferation and caused cytoreduction of CRPC in xenografts dependent on AR for growth and survival without causing toxicity.


Asunto(s)
Antagonistas de Receptores Androgénicos , Antineoplásicos Hormonales/uso terapéutico , Compuestos de Bencidrilo/uso terapéutico , Castración , Clorhidrinas/uso terapéutico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Neoplasias de la Próstata/tratamiento farmacológico , Andrógenos/farmacología , Animales , Antineoplásicos Hormonales/efectos adversos , Antineoplásicos Hormonales/farmacología , Apoptosis/efectos de los fármacos , Compuestos de Bencidrilo/efectos adversos , Compuestos de Bencidrilo/farmacología , Proteína de Unión a CREB/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Clorhidrinas/efectos adversos , Clorhidrinas/farmacología , ADN/genética , ADN/metabolismo , Expresión Génica/efectos de los fármacos , Humanos , Ligandos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Estructura Molecular , Recurrencia Local de Neoplasia/patología , Próstata/anatomía & histología , Próstata/efectos de los fármacos , Próstata/patología , Antígeno Prostático Específico/sangre , Antígeno Prostático Específico/genética , Antígeno Prostático Específico/metabolismo , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/cirugía , Unión Proteica/efectos de los fármacos , Unión Proteica/genética , Conformación Proteica/efectos de los fármacos , Dominios y Motivos de Interacción de Proteínas/efectos de los fármacos , Multimerización de Proteína/efectos de los fármacos , Receptores Androgénicos/metabolismo , Receptores de Esteroides/efectos de los fármacos , Elementos de Respuesta/genética , Serina Endopeptidasas/genética , Activación Transcripcional/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto
15.
Org Lett ; 10(21): 4947-50, 2008 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-18834139

RESUMEN

The new chlorinated peptides sintokamides A to E (1-5) have been isolated from specimens of the marine sponge Dysidea sp. collected in Indonesia. Their structures were elucidated by a combination of spectroscopic and single-crystal X-ray diffraction analyses. Sintokamide A (1) is an inhibitor of N-terminus transactivation of the androgen receptor in prostate cancer cells.


Asunto(s)
Compuestos de Cloro/química , Compuestos de Cloro/farmacología , Dysidea/química , Péptidos/química , Péptidos/farmacología , Neoplasias de la Próstata/metabolismo , Receptores Androgénicos/metabolismo , Animales , Línea Celular Tumoral , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Modelos Moleculares , Estructura Molecular , Neoplasias de la Próstata/genética , Receptores Androgénicos/genética , Activación Transcripcional/efectos de los fármacos
16.
Proc Natl Acad Sci U S A ; 104(4): 1331-6, 2007 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-17227854

RESUMEN

The androgen receptor (AR) is activated by both ligand-dependent and -independent mechanisms. Current therapies for prostate cancer target the ligand-binding domain in the C terminus of the AR. However, ligand-independent activation of the AR occurs by the N-terminal domain (NTD), making the NTD a potential novel target for the treatment of hormone refractory prostate cancer. A possible therapeutic approach is to overexpress an AR NTD peptide to create decoy molecules that competitively bind the interacting proteins required for activation of the endogenous full-length AR. We provide evidence that in vivo expression of AR NTD decoys decreased tumor incidence and inhibited the growth of prostate cancer tumors. This growth inhibition was characterized by a 10-fold decrease in serum levels of prostate-specific antigen (PSA) (46.7 ng/ml+/-19.9 vs. 432.4 ng/ml+/-201.3; P=0.0299) and a 4-fold decrease in tumor volume (92.2 mm3+/-43.4 vs. 331.4 mm3+/-85.5; P=0.011). AR NTD decoy molecules also delayed hormonal progression, as determined by time to rising PSA levels after castration of the host. The tumors treated with AR NTD decoys contained more apoptotic cells and fewer proliferating cells, whereas no effect was seen on the viability of cells that did not depend on the AR. This work provides further evidence of the importance of the NTD of the AR in the progression of prostate cancer and presents a target for the development of antagonists of the AR in the clinical management of this disease.


Asunto(s)
División Celular/fisiología , Neoplasias de la Próstata/patología , Receptores Androgénicos/fisiología , Animales , Apoptosis/fisiología , Línea Celular Tumoral , Proliferación Celular , Progresión de la Enfermedad , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID
17.
J Neurosci ; 26(3): 830-40, 2006 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-16421303

RESUMEN

Integrin-linked kinase (ILK) is a serine/threonine protein kinase that plays an important role in integrin signaling and cell proliferation. We used Cre recombinase (Cre)-loxP technology to study CNS restricted knock-out of the ilk gene by either Nestin-driven or gfap-driven Cre-mediated recombination. Developmental changes in ilk-excised brain regions are similar to those observed in mice lacking the integrin beta1 subunit in the CNS, including defective laminin deposition, abnormal glial morphology, and alterations in granule cell migration. Decreases in 6-bromodeoxyuridine (BrdU) pulse labeling and proliferating cell nuclear antigen expression in the external granule cell layer of the cerebellum demonstrated that proliferation is disrupted in granule cells lacking ILK. Previous studies have shown that laminin-sonic hedgehog (Shh)-induced granule cell precursor (GCP) proliferation is dependent on beta1 integrins, several of which bind laminin and interact with ILK through the beta1 cytoplasmic domain. Both ex vivo deletion of ilk and a small molecule inhibitor of ILK kinase activity decreased laminin-Shh-induced BrdU labeling in cultured GCPs. Together, these results implicate ILK as a critical effector in a signaling pathway necessary for granule cell proliferation and cerebellar development.


Asunto(s)
Proliferación Celular , Cerebelo/citología , Cerebelo/enzimología , Proteínas Serina-Treonina Quinasas/fisiología , Células Madre/citología , Células Madre/enzimología , Animales , Animales Recién Nacidos , Células Cultivadas , Cerebelo/crecimiento & desarrollo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Serina-Treonina Quinasas/deficiencia , Proteínas Serina-Treonina Quinasas/genética , Transducción de Señal/genética , Transducción de Señal/fisiología
18.
Cancer Res ; 66(1): 393-403, 2006 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-16397254

RESUMEN

The emerging paradigm of "oncogene addiction" has been called an Achilles' heel of cancer that can be exploited therapeutically. Here, we show that integrin-linked kinase (ILK), which is either activated or overexpressed in many types of cancers, is a critical regulator of breast cancer cell survival through the protein kinase B (PKB)/Akt pathway but is largely dispensable for the survival of normal breast epithelial cells and mesenchymal cells. We show that inhibition of ILK activity with a pharmacologic ILK inhibitor, QLT-0267, results in the inhibition of PKB/Akt Ser473 phosphorylation, stimulation of apoptosis, and a decrease in mammalian target of rapamycin (mTOR) expression in human breast cancer cells. In contrast, QLT-0267 treatment has no effect on PKB/Akt Ser473 phosphorylation or apoptosis in normal human breast epithelial, mouse fibroblast, or vascular smooth muscle cells. The inhibition of PKB/Akt Ser473 phosphorylation by QLT-0267 in breast cancer cells was rescued by a kinase-active ILK mutant but not by a kinase-dead ILK mutant. Furthermore, a dominant-negative ILK mutant increased apoptosis in the MDA-MB-231 breast cancer cell line but not in normal human breast epithelial cells. The inhibitor was active against ILK isolated from all cell types but did not have any effect on cell attachment and spreading. Our data point to an "ILK addiction" of breast cancer cells whereby they become dependent on ILK for cell survival through the mTOR-PKB/Akt signaling pathway and show that ILK is a promising target for the treatment of breast cancer.


Asunto(s)
Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Secuencia de Aminoácidos , Animales , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Mama/enzimología , Neoplasias de la Mama/enzimología , Neoplasias de la Mama/patología , Línea Celular Tumoral , Supervivencia Celular/fisiología , Activación Enzimática , Células Epiteliales/enzimología , Humanos , Masculino , Mesodermo/citología , Mesodermo/enzimología , Ratones , Datos de Secuencia Molecular , Células 3T3 NIH , Fosforilación , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/biosíntesis , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Serina-Treonina Quinasas TOR
19.
Lab Invest ; 85(11): 1392-404, 2005 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16155594

RESUMEN

Metastasis is the major cause of prostate cancer deaths and there is a need for clinically relevant in vivo models allowing elucidation of molecular and cellular mechanisms underlying metastatic behavior. Here we describe the development of a new in vivo model system for metastatic prostate cancer. Pieces of prostate cancer tissue from a patient were grafted in testosterone-supplemented male NOD-SCID mice at the subrenal capsule graft site permitting high tumor take rates. After five serial transplantations, the tumor tissues were grafted into mouse prostates. Resulting tumors and suspected metastatic lesions were subjected to histopathological and immunohistochemical analysis. Samples of metastatic tissue were regrafted in mouse anterior prostates and their growth and spread examined, leading to isolation from lymph nodes of a metastatic subline, PCa1-met. Orthotopic grafting of PCa1-met tissue in 47 hosts led in all cases to metastases to multiple organs (lymph nodes, lung, liver, kidney, spleen and, notably, bone). Histopathological analysis showed strong similarity between orthotopic grafts and their metastases. The latter were of human origin as indicated by immunostaining using antibodies against human mitochondria, androgen receptor, prostate-specific antigen and Ki-67. Spectral karyotyping showed few chromosomal alterations in the PCa1-met subline. This study indicates that transplantable subrenal capsule xenografts of human prostate cancer tissue in NOD-SCID mice can, as distinct from primary cancer tissue, be successfully grown in the orthotopic site. Orthotopic xenografts of the transplantable tumor lines and metastatic sublines can be used for studying various aspects of metastatic prostate cancer, including metastasis to bone.


Asunto(s)
Línea Celular Tumoral/trasplante , Modelos Animales de Enfermedad , Neoplasias de la Próstata/patología , Trasplante Heterotópico , Anciano , Animales , Humanos , Metástasis Linfática , Masculino , Ratones , Ratones SCID , Metástasis de la Neoplasia , Trasplante de Neoplasias , Neoplasias de la Próstata/fisiopatología , Trasplante Heterólogo
20.
Clin Cancer Res ; 10(5): 1860-9, 2004 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-15014041

RESUMEN

PURPOSE: Prostate cancer metastasizes to the skeleton to form osteoblastic lesions. Androgen ablation is the current treatment for metastatic prostate cancer. This therapy is palliative, and the disease will return in an androgen-independent form that is preceded by a rising titer of prostate-specific antigen (PSA). Here, we investigated the possibility that human osteoblasts might secrete factors that contribute to the emergence of androgen-independent prostate cancer. EXPERIMENTAL DESIGN: Primary cultures of human osteoblasts were used as a source of conditioned medium (OCM). Proliferation, expression of androgen-regulated genes, and transactivation of the androgen receptor (AR) were monitored in LNCaP human prostate cancer cells in response to OCM using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Northern blot analysis, and reporter gene constructs. Levels of interleukin-6 (IL-6) present in OCM were measured, and its contribution to proliferation and expression of PSA were investigated by neutralization studies with anti IL-6 antibodies. RESULTS: OCM increased the proliferation and expression of PSA at both the protein and RNA levels in LNCaP cells. Synergistic increases in the activities of PSA (6.1 kb)- and pARR(3)-tk-luciferase reporters were measured in cells cotreated with both OCM and androgen. OCM targeted the NH(2)-terminal domain of the AR. The effect of OCM on transcriptional activity of the AR was inhibited by an antiandrogen. Neutralizing antibodies to IL-6 blocked proliferation and expression of PSA by OCM. CONCLUSION: Osteoblasts secrete factors, such as IL-6, that cause androgen-independent induction of PSA gene expression and proliferation of prostate cancer cells by a mechanism that partially relies on the AR. Identifying such molecular mechanisms may lead to improved clinical management of metastatic prostate cancer.


Asunto(s)
Andrógenos/fisiología , Osteoblastos/fisiología , Antígeno Prostático Específico/genética , Neoplasias de la Próstata/patología , División Celular , Línea Celular Tumoral , Genes Reporteros , Humanos , Interleucina-6/metabolismo , Interleucina-6/farmacología , Luciferasas/genética , Masculino , Receptores Androgénicos/fisiología , Proteínas Recombinantes/farmacología , Transfección
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