RESUMEN
Increased transcription of ribosomal RNA genes (rDNA) by RNA Polymerase I is a common feature of human cancer, but whether it is required for the malignant phenotype remains unclear. We show that rDNA transcription can be therapeutically targeted with the small molecule CX-5461 to selectively kill B-lymphoma cells in vivo while maintaining a viable wild-type B cell population. The therapeutic effect is a consequence of nucleolar disruption and activation of p53-dependent apoptotic signaling. Human leukemia and lymphoma cell lines also show high sensitivity to inhibition of rDNA transcription that is dependent on p53 mutational status. These results identify selective inhibition of rDNA transcription as a therapeutic strategy for the cancer specific activation of p53 and treatment of hematologic malignancies.
Asunto(s)
Neoplasias/metabolismo , ARN Polimerasa I/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/metabolismo , Animales , Apoptosis , Benzotiazoles/farmacología , ADN Ribosómico/genética , Femenino , Ratones , Ratones Transgénicos , Naftiridinas/farmacología , Neoplasias/genética , Neoplasias/patología , ARN Ribosómico/genética , Transcripción GenéticaRESUMEN
Structure-activity relationship analysis in a series of 3-(5-((2-oxoindolin-3-ylidene)methyl)furan-2-yl)amides identified compound 13, a pan-Pim kinases inhibitor with excellent biochemical potency and kinase selectivity. Compound 13 exhibited in vitro synergy with chemotherapeutics and robust in vivo efficacy in two Pim kinases driven tumor models.
RESUMEN
Accelerated proliferation of solid tumor and hematologic cancer cells is linked to accelerated transcription of rDNA by the RNA polymerase I (Pol I) enzyme to produce elevated levels of rRNA (rRNA). Indeed, upregulation of Pol I, frequently caused by mutational alterations among tumor suppressors and oncogenes, is required for maintenance of the cancer phenotype and forms the basis for seeking selective inhibitors of Pol I as anticancer therapeutics. 2-(4-Methyl-[1,4]diazepan-1-yl)-5-oxo-5H-7-thia-1,11b-diaza-benzo[c]fluorene-6-carboxylic acid (5-methyl-pyrazin-2-ylmethyl)-amide (CX-5461, 7c) has been identified as the first potent, selective, and orally bioavailable inhibitor of RNA Pol I transcription with in vivo activity in tumor growth efficacy models. The preclinical data support the development of CX-5461 as an anticancer drug with potential for activity in several types of cancer.
RESUMEN
Protein kinase CK2 is a potential drug target for many diseases including cancer and inflammation disorders. The crystal structure of clinical candidate CX-4945 1 with CK2 revealed an indirect interaction with the protein through hydrogen bonding between the NH of the 3-chlorophenyl amine and a water molecule. Herein, we investigate the relevance of this hydrogen bond by preparing several novel tricyclic derivatives lacking a NH moiety at the same position. This SAR study allowed the discovery of highly potent CK2 inhibitors.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Quinasa de la Caseína II/antagonistas & inhibidores , Quinolinas/química , Quinasa de la Caseína II/química , Línea Celular Tumoral , Química Farmacéutica/métodos , Cristalografía por Rayos X/métodos , Diseño de Fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Concentración 50 Inhibidora , Modelos Químicos , Modelos Moleculares , Conformación Proteica , Quinolinas/síntesis química , Relación Estructura-ActividadRESUMEN
In this article we describe the preclinical characterization of 5-(3-chlorophenylamino) benzo[c][2,6]naphthyridine-8-carboxylic acid (CX-4945), the first orally available small molecule inhibitor of protein CK2 in clinical trials for cancer. CX-4945 was optimized as an ATP-competitive inhibitor of the CK2 holoenzyme (Ki = 0.38 nM). Iterative synthesis and screening of analogs, guided by molecular modeling, led to the discovery of orally available CX-4945. CK2 promotes signaling in the Akt pathway and CX-4945 suppresses the phosphorylation of Akt as well as other key downstream mediators of the pathway such as p21. CX-4945 induced apoptosis and caused cell cycle arrest in cancer cells in vitro. CX-4945 exhibited a dose-dependent antitumor activity in a xenograft model of PC3 prostate cancer model and was well tolerated. In vivo time-dependent reduction in the phosphorylation of the biomarker p21 at T145 was observed by immunohistochemistry. Inhibition of the newly validated CK2 target by CX-4945 represents a fresh therapeutic strategy for cancer.
Asunto(s)
Quinasa de la Caseína II/antagonistas & inhibidores , Naftiridinas/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Ensayos Antitumor por Modelo de Xenoinjerto , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Quinasa de la Caseína II/metabolismo , Caspasa 3/metabolismo , Caspasa 7/metabolismo , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Humanos , Inmunohistoquímica , Masculino , Ratones , Naftiridinas/química , Naftiridinas/farmacología , Fenazinas , Fosforilación/efectos de los fármacos , Neoplasias de la Próstata/enzimología , Neoplasias de la Próstata/patología , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Bibliotecas de Moléculas Pequeñas/administración & dosificación , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Estructura-ActividadRESUMEN
We describe the discovery of novel potent substituted pyrimido[4,5-c]quinoline ATP-competitive inhibitors of protein kinase CK2. A binding model of the inhibitors with the protein was elaborated on the basis of SAR and revealed various modes of interaction with the hinge region. Representative analog 14k (CK2 IC(50)=9 nM) showed anti-viral activity at nanomolar concentrations against HIV-1. Orally available compound 7e (CK2 IC(50)=3 nM) reduced pain in the phase II of a murine formalin model. These preliminary data confirm that properly optimized CK2 inhibitors may be used for anti-viral and pain therapy.
Asunto(s)
Analgésicos/farmacología , Antivirales/farmacología , Quinasa de la Caseína II/antagonistas & inhibidores , Quinolinas/farmacología , Analgésicos/química , Antivirales/química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Enlace de Hidrógeno , Quinolinas/química , Relación Estructura-ActividadRESUMEN
Herein we chronicle the discovery of CX-4945 (25n), a first-in-class, orally bioavailable ATP-competitive inhibitor of protein kinase CK2 in clinical trials for cancer. CK2 has long been considered a prime cancer drug target because of the roles of deregulated and overexpressed CK2 in cancer-promoting prosurvival and antiapoptotic pathways. These biological properties as well as the suitability of CK2's small ATP binding site for the design of selective inhibitors, led us to fashion novel therapeutic agents for cancer. The optimization leading to 25n (K(i) = 0.38 nM) was guided by molecular modeling, suggesting a strong binding of 25n resulting from a combination of hydrophobic interactions, an ionic bridge with Lys68, and hydrogen bonding with the hinge region. 25n was found to be highly selective, orally bioavailable across species (20-51%) and efficacious in xenograft models. The discovery of 25n will allow the therapeutic targeting of CK2 in humans for the first time.
Asunto(s)
Antineoplásicos/síntesis química , Quinasa de la Caseína II/antagonistas & inhibidores , Naftiridinas/síntesis química , Adenosina Trifosfato/metabolismo , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Unión Competitiva , Disponibilidad Biológica , Línea Celular Tumoral , Perros , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Ratones , Ratones Endogámicos ICR , Ratones Desnudos , Modelos Moleculares , Naftiridinas/química , Naftiridinas/farmacología , Trasplante de Neoplasias , Fenazinas , Ratas , Relación Estructura-Actividad , Trasplante HeterólogoRESUMEN
Deregulated ribosomal RNA synthesis is associated with uncontrolled cancer cell proliferation. RNA polymerase (Pol) I, the multiprotein complex that synthesizes rRNA, is activated widely in cancer. Thus, selective inhibitors of Pol I may offer a general therapeutic strategy to block cancer cell proliferation. Coupling medicinal chemistry efforts to tandem cell- and molecular-based screening led to the design of CX-5461, a potent small-molecule inhibitor of rRNA synthesis in cancer cells. CX-5461 selectively inhibits Pol I-driven transcription relative to Pol II-driven transcription, DNA replication, and protein translation. Molecular studies demonstrate that CX-5461 inhibits the initiation stage of rRNA synthesis and induces both senescence and autophagy, but not apoptosis, through a p53-independent process in solid tumor cell lines. CX-5461 is orally bioavailable and demonstrates in vivo antitumor activity against human solid tumors in murine xenograft models. Our findings position CX-5461 for investigational clinical trials as a potent, selective, and orally administered agent for cancer treatment.
Asunto(s)
Benzotiazoles/farmacología , Proliferación Celular/efectos de los fármacos , Naftiridinas/farmacología , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/patología , ARN Polimerasa I/antagonistas & inhibidores , ARN Ribosómico/biosíntesis , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Benzotiazoles/administración & dosificación , Benzotiazoles/uso terapéutico , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Células HCT116 , Células HeLa , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Terapia Molecular Dirigida/métodos , Naftiridinas/administración & dosificación , Naftiridinas/uso terapéutico , Neoplasias/metabolismo , ARN Polimerasa I/genética , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Malignant transformation and maintenance of the malignant phenotype depends on oncogenic and non-oncogenic proteins that are essential to mediate oncogene signaling and to support the altered physiologic demands induced by transformation. Protein kinase CK2 supports key prosurvival signaling pathways and represents a prototypical non-oncogene. In this study, we describe CX-4945, a potent and selective orally bioavailable small molecule inhibitor of CK2. The antiproliferative activity of CX-4945 against cancer cells correlated with expression levels of the CK2α catalytic subunit. Attenuation of PI3K/Akt signaling by CX-4945 was evidenced by dephosphorylation of Akt on the CK2-specific S129 site and the canonical S473 and T308 regulatory sites. CX-4945 caused cell-cycle arrest and selectively induced apoptosis in cancer cells relative to normal cells. In models of angiogenesis, CX-4945 inhibited human umbilical vein endothelial cell migration, tube formation, and blocked CK2-dependent hypoxia-induced factor 1 alpha (HIF-1α) transcription in cancer cells. When administered orally in murine xenograft models, CX-4945 was well tolerated and demonstrated robust antitumor activity with concomitant reductions of the mechanism-based biomarker phospho-p21 (T145). The observed antiproliferative and anti-angiogenic responses to CX-4945 in tumor cells and endothelial cells collectively illustrate that this compound exerts its antitumor effects through inhibition of CK2-dependent signaling in multiple pathways. Finally, CX-4945 is the first orally bioavailable small molecule inhibitor of CK2 to advance into human clinical trials, thereby paving the way for an entirely new class of targeted treatment for cancer.
Asunto(s)
Quinasa de la Caseína II/antagonistas & inhibidores , Neoplasias Inflamatorias de la Mama/tratamiento farmacológico , Naftiridinas/farmacología , Neoplasias Pancreáticas/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Administración Oral , Animales , Disponibilidad Biológica , Línea Celular Tumoral , Células Endoteliales/citología , Células Endoteliales/efectos de los fármacos , Femenino , Células HeLa , Humanos , Neoplasias Inflamatorias de la Mama/irrigación sanguínea , Neoplasias Inflamatorias de la Mama/enzimología , Ratones , Naftiridinas/farmacocinética , Neovascularización Patológica/tratamiento farmacológico , Neovascularización Patológica/metabolismo , Neovascularización Patológica/patología , Neoplasias Pancreáticas/irrigación sanguínea , Neoplasias Pancreáticas/enzimología , Fenazinas , Inhibidores de Proteínas Quinasas/farmacocinética , Distribución Aleatoria , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Hallmark deregulated signaling in cancer cells drives excessive ribosome biogenesis within the nucleolus, which elicits unbridled cell growth and proliferation. The rate-limiting step of ribosome biogenesis is synthesis of rRNA (building blocks of ribosomes) by RNA Polymerase I (Pol I). Numerous kinase pathways and products of proto-oncogenes can up-regulate Pol I, whereas tumor suppressor proteins can inhibit rRNA synthesis. In tumorigenesis, activating mutations in certain cancer-associated kinases and loss-of-function mutations in tumor suppressors lead to deregulated signaling that stimulates Pol I transcription with resultant increases in ribosome biogenesis, protein synthesis, cell growth, and proliferation. Certain anticancer therapeutics, such as cisplatin and 5-fluorouracil, reportedly exert, at least partially, their activity through disruption of ribosome biogenesis, yet many prime targets for anticancer drugs within the ribosome synthetic machinery of the nucleolus remain largely unexploited. Herein, we describe CX-3543, a small molecule nucleolus-targeting agent that selectively disrupts nucleolin/rDNA G-quadruplex complexes in the nucleolus, thereby inhibiting Pol I transcription and inducing apoptosis in cancer cells. CX-3543 is the first G-quadruplex interactive agent to enter human clinical trials, and it is currently under evaluation against carcinoid/neuroendocrine tumors in a phase II clinical trial.
Asunto(s)
Benzoxazinas/farmacología , Neoplasias/tratamiento farmacológico , Quinolonas/farmacología , ARN Ribosómico/antagonistas & inhibidores , ARN Ribosómico/biosíntesis , Animales , Apoptosis/efectos de los fármacos , Benzoxazinas/farmacocinética , Línea Celular Tumoral , Nucléolo Celular/efectos de los fármacos , Nucléolo Celular/metabolismo , ADN Polimerasa I/antagonistas & inhibidores , ADN Polimerasa I/genética , ADN Polimerasa I/metabolismo , ADN-Topoisomerasas de Tipo I/metabolismo , ADN-Topoisomerasas de Tipo II/metabolismo , Femenino , G-Cuádruplex/efectos de los fármacos , Células HL-60 , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Ratones SCID , Neoplasias/genética , Neoplasias/metabolismo , Fosfoproteínas/antagonistas & inhibidores , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Quinolonas/farmacocinética , Proteínas de Unión al ARN/antagonistas & inhibidores , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Telómero/efectos de los fármacos , Transcripción Genética/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , NucleolinaRESUMEN
Psorospermin is a natural product that has been shown to have activity against drug-resistant leukemia lines and AIDS-related lymphoma. It has also been shown to alkylate DNA through an epoxide-mediated electrophilic attack, and this alkylation is greatly enhanced at specific sites by topoisomerase II. In this article, we describe the synthesis of the two diastereomers of O5-methyl psorospermin and their in vitro activity against a range of solid and hematopoietic tumors. The diastereomeric pair (+/-)-(2'R,3'R) having the naturally occurring enantiomer (2'R,3'R) is the most active across all the cell lines and shows approximately equal activity in both drug-sensitive and drug-resistant cell lines. In subsequent studies using all four enantiomers of O5-methyl psorospermin, the order of biological potency is (2'R,3'R) > (2'R,3'S) = (2'S,3'R) > (2'S,3'S). This order of potency is also found in the topoisomerase II-induced alkylation of O5-methyl psorospermin and can be rationalized by molecular modeling of the psorospermin-duplex binding complex. Therefore, this study defines the optimum stereochemical requirements for both the topoisomerase II-induced alkylation of DNA and the biological activity by psorospermin and its O5-methyl derivatives. Finally, (2'R,3'R) psorospermin was found to be as effective as gemcitabine in slowing tumor growth in vivo in a MiaPaCa pancreatic cancer model. In addition, (2'R,3'R) psorospermin in combination with gemcitabine was found to show an at least additive effect in slowing tumor growth of MiaPaCa.
Asunto(s)
ADN-Topoisomerasas de Tipo II/metabolismo , ADN/química , Ensayos de Selección de Medicamentos Antitumorales , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/patología , Xantonas/química , Xantonas/síntesis química , Animales , Protocolos de Quimioterapia Combinada Antineoplásica , Peso Corporal , Línea Celular , Línea Celular Tumoral , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacología , Compuestos Epoxi/química , Técnicas In Vitro , Concentración 50 Inhibidora , Leucemia/tratamiento farmacológico , Linfoma/tratamiento farmacológico , Ratones , Ratones Desnudos , Modelos Químicos , Modelos Moleculares , Neoplasias Pancreáticas/enzimología , Estereoisomerismo , Factores de Tiempo , Xantonas/administración & dosificación , GemcitabinaRESUMEN
Two new classes of tricyclic-based corticotropin-releasing factor (CRF(1)) receptor-1 antagonists were designed by constraining known 1H-pyrrolo[2,3-b]pyridine and 1H-pyrazolo[3,4-b]pyridine ligands. Pyrrole- and pyrazole-based molecules 19g and 22a, respectively, were discovered that potently bind the recombinant CRF(1) receptor (K(i) = 3.5, 2.9 nM) and inhibit adrenocorticotropic hormone (ACTH) release from rat pituitary cell culture (IC(50) = 14, 6.8 nM). These compounds show good oral bioavailabity (F = 24%, 7.0%) and serum half-lives in rats (t(1/2) = 6.3, 12 h) and penetrate the rat brain ([brain]/[plasma] = 0.27, 0.52) but tend toward large volumes of distribution (V(D) = 38, 44 L kg(-1)) and rapid clearances (CL = 70, 43 mL min(-1) kg(-1)). When given orally, both the pyrazole and the pyrrole leads dose-dependently inhibit stress-induced ACTH release in vivo. ACTH reductions of 84-86% were observed for 30 mg kg(-1) doses.