RESUMO
Rac and Cdc42, are homologous GTPases that regulate cell migration, invasion, and cell cycle progression; thus, representing key targets for metastasis therapy. We previously reported on the efficacy of MBQ-167, which blocks both Rac1 and Cdc42 in breast cancer cells and mouse models of metastasis. To identify compounds with increased activity, a panel of MBQ-167 derivatives was synthesized, maintaining its 9-ethyl-3-(1H-1,2,3-triazol-1-yl)-9H-carbazole core. Similar to MBQ-167, MBQ-168 and EHop-097, inhibit activation of Rac and Rac1B splice variant and breast cancer cell viability, and induce apoptosis. MBQ-167 and MBQ-168 inhibit Rac and Cdc42 by interfering with guanine nucleotide binding, and MBQ-168 is a more effective inhibitor of PAK (1,2,3) activation. EHop-097 acts via a different mechanism by inhibiting the interaction of the guanine nucleotide exchange factor (GEF) Vav with Rac. MBQ-168 and EHop-097 inhibit metastatic breast cancer cell migration, and MBQ-168 promotes loss of cancer cell polarity to result in disorganization of the actin cytoskeleton and detachment from the substratum. In lung cancer cells, MBQ-168 is more effective than MBQ-167 or EHop-097 at reducing ruffle formation in response to EGF. Comparable to MBQ-167, MBQ-168 significantly inhibits HER2+ tumor growth and metastasis to lung, liver, and spleen. Both MBQ-167 and MBQ-168 inhibit the cytochrome P450 (CYP) enzymes 3A4, 2C9, and 2C19. However, MBQ-168 is ~10X less potent than MBQ-167 at inhibiting CYP3A4, thus demonstrating its utility in relevant combination therapies. In conclusion, the MBQ-167 derivatives MBQ-168 and EHop-097 are additional promising anti metastatic cancer compounds with similar and distinct mechanisms.
Assuntos
Proteínas de Ligação ao GTP , Proteínas rac de Ligação ao GTP , Camundongos , Animais , Proteínas rac de Ligação ao GTP/genética , Proteínas de Ligação ao GTP/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Movimento Celular , Divisão CelularRESUMO
Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer, with a high predisposition for locally invasive and metastatic cancer. With the objective to reduce cancer metastasis, we developed small molecule inhibitors to target the drivers of metastasis, the Rho GTPases Rac and Cdc42. Of these, MBQ-167 inhibits both Rac and Cdc42 with IC50s of 103 and 78 nmol/L, respectively; and consequently, inhibits p21-activated kinase (PAK) signaling, metastatic cancer cell proliferation, migration, and mammosphere growth; induces cell-cycle arrest and apoptosis; and decreases HER2-type mammary fatpad tumor growth and metastasis (Humphries-Bickley and colleagues, 2017). Herein, we used nuclear magnetic resonance to show that MBQ-167 directly interacts with Rac1 to displace specific amino acids, and consequently inhibits Rac.GTP loading and viability in TNBC cell lines. Phosphokinome arrays in the MDA-MB-231 human TNBC cells show that phosphorylation status of kinases independent of the Rac/Cdc42/PAK pathway are not significantly changed following 200 nmol/L MBQ-167 treatment. Western blotting shows that initial increases in phospho-c-Jun and phospho-CREB in response to MBQ-167 are not sustained with prolonged exposure, as also confirmed by a decrease in their transcriptional targets. MBQ-167 inhibits tumor growth, and spontaneous and experimental metastasis in immunocompromised (human TNBC) and immunocompetent (mouse TNBC) models. Moreover, per oral administration of MBQ-167 at 100 mg/kg body weight is not toxic to immunocompetent BALB/c mice and has a half-life of 4.6 hours in plasma. These results highlight the specificity, potency, and bioavailability of MBQ-167, and support its clinical potential as a TNBC therapeutic.
Assuntos
Neoplasias de Mama Triplo Negativas/genética , Proteína cdc42 de Ligação ao GTP/antagonistas & inibidores , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Camundongos SCID , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
BACKGROUND: Even though targeted therapies are available for cancers expressing oncogenic epidermal growth receptor (EGFR) and (or) human EGFR2 (HER2), acquired or intrinsic resistance often confounds therapy success. Common mechanisms of therapy resistance involve activating receptor point mutations and (or) upregulation of signaling downstream of EGFR/HER2 to Akt and (or) mitogen activated protein kinase (MAPK) pathways. However, additional pathways of resistance may exist thus, confounding successful therapy. METHODS: To determine novel mechanisms of EGFR/HER2 therapy resistance in breast cancer, gefitinib or lapatinib resistant variants were created from SKBR3 breast cancer cells. Syngenic therapy sensitive and resistant SKBR3 variants were characterized for mechanisms of resistance by mammosphere assays, viability assays, and western blotting for total and phospho proteins. RESULTS: Gefitinib and lapatinib treatments reduced mammosphere formation in the sensitive cells, but not in the therapy resistant variants, indicating enhanced mesenchymal and cancer stem cell-like characteristics in therapy resistant cells. The therapy resistant variants did not show significant changes in known therapy resistant pathways of AKT and MAPK activities downstream of EGFR/HER2. However, these cells exhibited elevated expression and activation of the small GTPase Rac, which is a pivotal intermediate of GFR signaling in EMT and metastasis. Therefore, the potential of the Rac inhibitors EHop-016 and MBQ-167 to overcome therapy resistance was tested, and found to inhibit viability and induce apoptosis of therapy resistant cells. CONCLUSIONS: Rac inhibition may represent a viable strategy for treatment of EGFR/HER2 targeted therapy resistant breast cancer.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias da Mama/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas rac de Ligação ao GTP/antagonistas & inibidores , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apoptose , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carbazóis/farmacologia , Carbazóis/uso terapêutico , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Feminino , Mutação com Ganho de Função , Gefitinibe/farmacologia , Gefitinibe/uso terapêutico , Regulação Neoplásica da Expressão Gênica , Humanos , Lapatinib , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Mutação Puntual , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Receptor ErbB-2/antagonistas & inibidores , Receptor ErbB-2/genética , Esferoides Celulares , Regulação para CimaRESUMO
The Rho GTPases Rac (Ras-related C3 botulinum toxin substrate) and Cdc42 (cell division control protein 42 homolog) regulate cell functions governing cancer malignancy, including cell polarity, migration, and cell-cycle progression. Accordingly, our recently developed Rac inhibitor EHop-016 (IC50, 1,100 nmol/L) inhibits cancer cell migration and viability and reduces tumor growth, metastasis, and angiogenesis in vivo Herein, we describe MBQ-167, which inhibits Rac and Cdc42 with IC50 values of 103 and 78 nmol/L, respectively, in metastatic breast cancer cells. Consequently, MBQ-167 significantly decreases Rac and Cdc42 downstream effector p21-activated kinase (PAK) signaling and the activity of STAT3, without affecting Rho, MAPK, or Akt activities. MBQ-167 also inhibits breast cancer cell migration, viability, and mammosphere formation. Moreover, MBQ-167 affects cancer cells that have undergone epithelial-to-mesenchymal transition by a loss of cell polarity and inhibition of cell surface actin-based extensions to ultimately result in detachment from the substratum. Prolonged incubation (120 hours) in MBQ-167 decreases metastatic cancer cell viability with a GI50 of approximately 130 nmol/L, without affecting noncancer mammary epithelial cells. The loss in cancer cell viability is due to MBQ-167-mediated G2-M cell-cycle arrest and subsequent apoptosis, especially of the detached cells. In vivo, MBQ-167 inhibits mammary tumor growth and metastasis in immunocompromised mice by approximately 90%. In conclusion, MBQ-167 is 10× more potent than other currently available Rac/Cdc42 inhibitors and has the potential to be developed as an anticancer drug, as well as a dual inhibitory probe for the study of Rac and Cdc42. Mol Cancer Ther; 16(5); 805-18. ©2017 AACR.
Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Proteína cdc42 de Ligação ao GTP/antagonistas & inibidores , Proteína cdc42 de Ligação ao GTP/genética , Proteínas rac1 de Ligação ao GTP/genética , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carbazóis/administração & dosagem , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Camundongos , Metástase Neoplásica , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Pirimidinas/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidoresRESUMO
Cinco pacientes con púrpura trombótica trombocitopénica (PTT) fueron seleccionados al azar para ser tratados con infusión de plasma fresco (dos pacientes) o plasmaféresis (tres pacientes). En todos los casos se observó una remisión completa 2 a 4 días después de que se inició el tratamiento. Estos resultados preliminares muestran que tanto la infusión de plasma fresco como la plasmaféresis son procedimientos terapéuticos adecuados en la PTT, por lo que consideramos que la infusión de plasma fresco se podría considerar como la primera opción terapéutica, ya que es de menos costo por no requerir de equipos especiales
Assuntos
Humanos , Plasmaferese , Púrpura Trombocitopênica Trombótica/terapiaRESUMO
Se analizan la semiología clínica y la evolución de 72 casos con síndrome mielodisplásico primario (SMP). El diagnóstico fue de anemia refractaria (AR) en 20, anemia sideroblástica (AS) en 7; anemia refractaria con exceso de blastos (ARCEB) en 26; anemia refractaria con exceso de blastos en transformación (ARCEB-t) en 14 y los cinco pacientes restantes tuvieron leucemia mielomonocítica crónica (LMMC). Ma mediana de edad fue de 64 años, con un discreto predominio del sexo masculino. La anemia fue el dato clínico más frecuente (94%), pero la infección y la hemorragias fueron las complicaciones evolutivas más frecuentes, así como la causa de muerte de estos pacientes. Doce de los mismos (18%) tuvieron una transformación a leucemia aguda. La mediana de la sobrevida fue mejor en pacientes con AR (34 meses) y AS (32 meses) que en pacientes con ARCEB (11 meses), ARCEB-t (8 meses) y LMMC (13 meses) p < 0.01. El diagnóstico se pudo sospechar en la citología hemática en el 83% de los casos y se confirmó en el aspirado de la médula ósea. Los intentos terapéuticos han sido infructuosos y el 80% de los pacientes requirieron de transfusiones de glóbulos rojos en forma periódica
Assuntos
Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Anemia/complicações , Hemorragia/complicações , Leucemia/complicações , Defeitos do Tubo Neural/etiologia , Transfusão de SangueRESUMO
Se trataron con 600 mg de danazol, 42 pacientes con síndrome mielodisplásico (SMD) por un minimo de tres meses. En 10 pacientes se observó una buena respuesta, mientras que en 6 se observó una respuesta parcial: los restantes 26 pacientes fueron considerados como fracasos. La mediana de la supervivencia de los pacientes que respondieron fue de 43 meses, la cual es significativamente mejor que los 7 meses que se observan en los pacientes en que esta forma de tratamiento fue considerada como fracaso (p v 0.01). La toxidad observada fue mínima y no fue necesario modificar el programa terapéutico por esta razón. Los subgrupos morfológicos con anemia refractaria y con anemia refractaria con exceso de blastos fueron en los que su tuvieron en mayor número de respuestas positivas. El uso de danazol en pacientes con SMD debe ser considerado como una opción, ya que además de tener uan toxicidad mínima, puede modificar de manera significativa los parámetros hematológicos y la supervivencia. Este fármaco, podría considerarse para el tratamiento inicial, antes de que otros, generalmente más tóxicos, sea usado en los SMD