RESUMEN
Parasitic diseases are a major public health problem worldwide. Plant-derived products appear to be ideal candidates from a biotechnological perspective, being sustainable and environmentally friendly. The antiparasitic properties of Carica papaya have been attributed to some of its components, including papain and other compounds that are concentrated in the latex and seeds. This study demonstrated in vitro a high and insignificantly different cysticidal activity of soluble extract that was obtained after the disruption of nontransformed wild-type (WT) cells as well as transformed papaya calluses (PC-9, PC-12, and PC-23) and papaya cell suspensions (CS-9, CS-12, and CS-23). In vivo, cell suspensions of CS-WT and CS-23 that had been previously lyophilized were tested with respect to their cysticidal effects, compared with those of three commercial antiparasitic drugs. CS-WT and CS-23 together reduced the number of cysticerci, the number of buds, and the percentage of calcified cysticerci in a similar extent to albendazole and niclosamide, whereas ivermectin was less effective. Mice were then orally immunized with CS-23 that expressed the anti-cysticercal KETc7 antigen (10 µg/mouse), CS-WT (10 mg/mouse), or both together to evaluate their preventive properties. CS-23 and CS-WT significantly reduced the expected parasite and increased the percentage of calcified cysticerci as well as recovery, being more effective when employed together. The results reported in this study support the feasibility of the development of an anti-cysticercosis vaccine from cells of C. papaya in in vitro cultures, as they are a source of an anthelmintic, natural, and reproducible product.
Asunto(s)
Carica , Ratones , Animales , Suspensiones , Albendazol , Extractos Vegetales/farmacología , SemillasRESUMEN
Although there are currently several factors that allow measuring the risk of having breast cancer or predicting its progression, the underlying causes of this malignancy have remained unknown. Several molecular studies have described some mechanisms involved in the progress of breast cancer. These have helped in identifying new targets with therapeutic potential. However, despite the therapeutic strategies implemented from the advances achieved in breast cancer research, a large percentage of patients with breast cancer die due to the spread of malignant cells to other tissues or organs, such as bones and lungs. Therefore, determining the processes that promote the migration of malignant cells remains one of the greatest challenges for oncological research. Several research groups have reported evidence on how the dedifferentiation of tumor cells leads to the acquisition of stemness characteristics, such as invasion, metastasis, the capability to evade the immunological response, and resistance to several cytotoxic drugs. These phenotypic changes have been associated with a complex reprogramming of gene expression in tumor cells during the Epithelial- Mesenchymal Transition (EMT). Considering the determining role that the transcriptional regulation plays in the expression of the specific characteristics and attributes of breast cancer during ETM, in the present work, we reviewed and analyzed several transcriptional mechanisms that support the mesenchymal phenotype. In the same way, we established the importance of transcription factors with a therapeutic perspective in the progress of breast cancer.
Asunto(s)
Antineoplásicos , Neoplasias de la Mama , Antineoplásicos/farmacología , Neoplasias de la Mama/patología , Línea Celular Tumoral , Transición Epitelial-Mesenquimal/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Factores de Transcripción/genéticaRESUMEN
Although significant progress has been made in the implementation of new breast cancer treatments over the last three decades, this neoplasm annually continues to show high worldwide rates of morbidity and mortality. In consequence, the search for novel therapies with greater effectiveness and specificity has not come to a stop. Among the alternative therapeutic targets, the human gonadotropin-releasing hormone type I and type II (hGnRH-I and hGnRH-II, respectively) and its receptor, the human gonadotropin-releasing hormone receptor type I (hGnRHR-I), have shown to be powerful therapeutic targets to decrease the adverse effects of this disease. In the present review, we describe how the administration of GnRH analogs is able to reduce circulating concentrations of estrogen in premenopausal women through their action on the hypothalamus-pituitary-ovarian axis, consequently reducing the growth of breast tumors and disease recurrence. Also, it has been mentioned that, regardless of the suppression of synthesis and secretion of ovarian steroids, GnRH agonists exert direct anticancer action, such as the reduction of tumor growth and cell invasion. In addition, we discuss the effects on breast cancer of the hGnRH-I and hGnRH-II agonist and antagonist, non-peptide GnRH antagonists, and cytotoxic analogs of GnRH and their implication as novel adjuvant therapies as antitumor agents for reducing the adverse effects of breast cancer. In conclusion, we suggest that the hGnRH/hGnRHR system is a promising target for pharmaceutical development in the treatment of breast cancer, especially for the treatment of advanced states of this disease.
RESUMEN
Taeniasis-cysticercosis, a zoonosis caused by Taenia solium, is prevalent in underdeveloped countries, where marginalization promotes its continued transmission. Pig cysticercosis, an essential stage for transmission, is preventable by vaccination. An efficient multiepitope vaccine against pig cysticercosis, S3Pvac, was developed. Previous studies showed that antibodies against one of the S3Pvac components, GK-1, are capable of damaging T. solium cysticerci, inhibiting their ability to transform into the adult stage in golden hamster gut. This study is aimed to evaluate one of the mechanisms that could mediate anti-GK-1 antibody-dependent protection. To this end, pig anti-GK-1 antibodies were produced and purified by using protein A. Proteomic analysis showed that the induced antibodies recognized the respective native cysticercal protein KE7 (Bobes et al. Infect Immun 85:e00395-17, 2017) and two additional T. solium proteins (endophilin B1 and Gp50). A new procedure to evaluate cysticercus viability, based on quantifying the cytochrome c released after parasite damage, was developed. Taenia crassiceps cysticerci were cultured in the presence of differing amounts of anti-GK-1 antibody and complement in a saturating concentration, along with the respective controls. Cysticercus viability was assessed by recording parasite motility, trypan blue exclusion, and cytochrome c levels in cysticercal soluble extract. Anti-GK-1 antibody significantly increased cysticercus damage as measured by all three methods. Parasite evaluation by electron microscopy after treatment with anti-GK-1 antibody plus complement demonstrated cysticercus damage as shorter, capsule-severed microtrichia; a decrease in glycocalyx length with respect to untreated cysts; and disaggregated desmosomes. These results demonstrate that anti-GK-1 antibodies damage cysticerci through classic complement activation.
Asunto(s)
Anticuerpos Antihelmínticos/inmunología , Activación de Complemento , Taenia/inmunología , Animales , Antígenos Helmínticos/inmunología , Cricetinae , Cisticercosis , Femenino , Mesocricetus , Ratones , Ratones Endogámicos BALB C , Proteómica , Porcinos , Teniasis/inmunologíaRESUMEN
Recently, an increasing amount of evidence indicates that human gonadotropin-releasing hormone (hGnRH) and its receptor (hGnRHR) are important regulatory components not only to the reproduction process but also in the regulation of some cancer cell functions such as cell proliferation, in both hormone-dependent and -independent types of tumors. The hGnRHR is a naturally misfolded protein that is retained mostly in the endoplasmic reticulum; however, this mechanism can be overcome by treatment with several pharmacoperones, therefore, increasing the amount of receptors in the cell membrane. In addition, several reports indicate that the expression level of hGnRHR in tumor cells is even lower than in pituitary or gonadotrope cells. The signal transduction pathways activated by hGnRH in both gonadotrope and different cancer cell types are described in the present review. We also discuss how the rescue of misfolded receptors in tumor cells could be a promising strategy for cancer therapy.
Asunto(s)
Hormona Liberadora de Gonadotropina/metabolismo , Neoplasias/metabolismo , Reproducción , Secuencia de Aminoácidos , Neoplasias de la Mama/metabolismo , Membrana Celular/metabolismo , Neoplasias Endometriales/metabolismo , Femenino , Regulación de la Expresión Génica , Hormonas/metabolismo , Humanos , Masculino , Datos de Secuencia Molecular , Neoplasias Ováricas/metabolismo , Hipófisis/metabolismo , Neoplasias de la Próstata/metabolismo , Dominios Proteicos , Pliegue de Proteína , Receptores LHRH/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND: Gonadotropin-releasing hormone (GnRH) and its receptor (GnRHR) are both expressed by a number of malignant tumors, including those of the breast. In the latter, both behave as potent inhibitors of invasion. Nevertheless, the signaling pathways whereby the activated GnRH/GnRHR system exerts this effect have not been clearly established. In this study, we provide experimental evidence that describes components of the mechanism(s) whereby GnRH inhibits breast cancer cell invasion. METHODS: Actin polymerization and substrate adhesion was measured in the highly invasive cell line, MDA-MB-231 transiently expressing the wild-type or mutant DesK191 GnRHR by fluorometry, flow cytometric analysis, and confocal microscopy, in the absence or presence of GnRH agonist. The effect of RhoA-GTP on stress fiber formation and focal adhesion assembly was measured in MDA-MB-231 cells co-expressing the GnRHRs and the GAP domain of human p190Rho GAP-A or the dominant negative mutant GAP-Y1284D. Cell invasion was determined by the transwell migration assay. RESULTS: Agonist-stimulated activation of the wild-type GnRHR and the highly plasma membrane expressed mutant GnRHR-DesK191 transiently transfected to MDA-MB-231 cells, favored F-actin polymerization and substrate adhesion. Confocal imaging allowed detection of an association between F-actin levels and the increase in stress fibers promoted by exposure to GnRH. Pull-down assays showed that the effects observed on actin cytoskeleton resulted from GnRH-stimulated activation of RhoA GTPase. Activation of this small G protein favored the marked increase in both cell adhesion to Collagen-I and number of focal adhesion complexes leading to inhibition of the invasion capacity of MDA-MB-231 cells as disclosed by assays in Transwell Chambers. CONCLUSIONS: We here show that GnRH inhibits invasion of highly invasive breast cancer-derived MDA-MB-231 cells. This effect is mediated through an increase in substrate adhesion promoted by activation of RhoA GTPase and formation of stress fibers and focal adhesions. These observations offer new insights into the molecular mechanisms whereby activation of overexpressed GnRHRs affects cell invasion potential of this malignant cell line, and provide opportunities for designing mechanism-based adjuvant therapies for breast cancer.
Asunto(s)
Actinas/metabolismo , Movimiento Celular , Receptores LHRH/metabolismo , Proteína de Unión al GTP rhoA/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Buserelina/metabolismo , Buserelina/farmacología , Línea Celular Tumoral , Activación Enzimática/efectos de los fármacos , Femenino , Citometría de Flujo , Fluorometría , Adhesiones Focales/efectos de los fármacos , Hormona Liberadora de Gonadotropina/farmacología , Humanos , Immunoblotting , Células MCF-7 , Microscopía Confocal , Mutación , Invasividad Neoplásica , Polimerizacion/efectos de los fármacos , Receptores LHRH/agonistas , Receptores LHRH/genética , Fibras de Estrés/metabolismo , Transfección , Proteína de Unión al GTP rhoA/genéticaRESUMEN
The pathogenic mechanisms whereby the Thr104Ile and Tyr108Cys mutations in the gonadotropin-releasing hormone receptor (GnRHR) gene cause hypogonadotropic hypogonadism in humans are unknown. Transient expression of Thr104Ile and Tyr108Cys mutants in COS-7 cells revealed that both GnRHR mutants neither bind nor respond to agonist. Removal of Lys191 rescued function of both mutants, while addition of a carboxyl-terminal targeting sequence only rescued function of the Thr104Ile mutant. Exposure to the pharmacoperone In3 rescued almost completely Thr104Ile mutant function to wild-type levels, whereas rescue was partial for the Tyr108Cys GnRHR. Additional mutations that block formation of bridges involving Cys108 showed that a Cys108-Cys200 disulfide bridge is the predominant moiety formed in the Tyr108Cys mutant. Thr104Ile and Tyr108Cys GnRHRs are misfolded structures whose function is rescuable by genetic and/or pharmacological strategies. The Tyr108Cys mutant forms an aberrant disulfide bridge that prevents formation of the required Cys14-Cys200 bridge essential for GnRHR plasma membrane expression.
Asunto(s)
Hipogonadismo/genética , Mutación Missense , Receptores LHRH/genética , Unión Competitiva , Buserelina/farmacología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Concentración 50 Inhibidora , Fosfatos de Inositol/metabolismo , Simulación de Dinámica Molecular , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Receptores LHRH/agonistas , Receptores LHRH/metabolismoRESUMEN
Current evidence indicates that G protein-coupled receptors form dimers that may affect biogenesis and membrane targeting of the complexed receptors. We here analyzed whether expression-deficient follicle-stimulating hormone receptor (FSHR) mutants exert dominant negative actions on wild-type FSHR cell surface membrane expression. Co-transfection of constant amounts of wild-type receptor cDNA and increasing quantities of mutant (R556A or R618A) FSHR cDNAs progressively decreased agonist-stimulated cAMP accumulation, [(125)I]-FSH binding, and plasma membrane expression of the mature wild-type FSHR species. Co-transfection of wild-type FSHR fragments involving transmembrane domains 5-6, or transmembrane domain 7 and/or the carboxyl-terminus specifically rescued wild-type FSHR expression from the transdominant inhibition by the mutants. Mutant FSHRs also inhibited function of the luteinizing hormone receptor but not that of the thyrotropin receptor or non-related receptors. Defective intracellular transport and/or interference with proper maturation due to formation of misfolded mutant:wild-type receptor complexes may explain the negative effects provoked by the altered FSHRs.
Asunto(s)
Regulación de la Expresión Génica , Mutación , Receptores de Superficie Celular/metabolismo , Receptores de HFE/genética , Receptores de HFE/metabolismo , Secuencia de Aminoácidos , Western Blotting , Línea Celular , Dimerización , Electroforesis en Gel de Poliacrilamida , Humanos , Datos de Secuencia Molecular , Pliegue de ProteínaRESUMEN
In the present study, we analyzed the role of Lys191 on function, structure, and dynamic behavior of the human GnRH receptor (hGnRHR) and the formation of the Cys14-Cys200 bridge, which is essential for receptor trafficking to the plasma membrane. Several mutants were studied; mutants lacked either the Cys14-Cys200 bridge, Lys191 or both. The markedly reduced expression and function of a Cys14Ser mutant lacking the 14-200 bridge, was nearly restored to wild-type/DeltaLys191 levels upon deletion of Lys191. Lys191 removal resulted in changes in the dynamic behavior of the mutants as disclosed by molecular dynamics simulations: the distance between the sulfur- (or oxygen-) sulfur groups of Cys (or Ser)14 and Cys200 was shorter and more constant, and the conformation of the NH(2)-terminus and the exoloop 2 exhibited fewer fluctuations than when Lys191 was present. These data provide novel information on the role of Lys191 in defining an optimal configuration for the hGnRHR intracellular trafficking and function.
Asunto(s)
Lisina/fisiología , Mutagénesis Sitio-Dirigida , Receptores LHRH/química , Receptores LHRH/genética , Animales , Sitios de Unión/genética , Buserelina/farmacocinética , Células COS , Chlorocebus aethiops , Simulación por Computador , Humanos , Enlace de Hidrógeno , Lisina/genética , Modelos Moleculares , Proteínas Mutantes/química , Conformación Proteica , Transporte de Proteínas/genética , Receptores LHRH/metabolismo , Receptores LHRH/fisiologíaRESUMEN
BACKGROUND: Some sub-groups of cutaneous squamous cell carcinoma (CSCC) display a higher risk for regional metastasis. Sentinel lymph node staging has been used successfully to evaluate nodal metastasis in selective tumors. OBJECTIVE: Assess the feasibility of sentinel node to detect occult regional lymph node metastasis in high-risk CSCC. MATERIAL AND METHODS: Between January 2002 and March 2004, a total of 20 patients received pre-operative lymphoscintigraphy and sentinel lymphadenectomy for high-risk CSCC with clinically non-palpable regional lymph nodes. RESULTS: In one of each 5 patients (20%), sentinel lymph node showed histological evidence of microinvolvement. No patients with negative sentinel node showed tumor dissemination during follow-up, with a mean of 23.5 months (range 7-44). CONCLUSIONS: Sentinel lymph node biopsy is technically feasible with low morbidity. Sentinel lymphadenectomy may play an important role in the management of high-risk CSCC with clinically non-palpable regional lymph nodes. This technique can help identify patients with regional lymph node metastases who may benefit from complete lymphadenectomy. This improved staging may allow clinicians to better stratify patients who might benefit from adjuvant therapy.
Asunto(s)
Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/secundario , Biopsia del Ganglio Linfático Centinela , Neoplasias Cutáneas/patología , Anciano , Anciano de 80 o más Años , Estudios de Factibilidad , Femenino , Humanos , Metástasis Linfática , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
Introducción: Un subgrupo de pacientes con carcinoma epidermoide cutáneo (CEC) tiene alto riesgo de presentar metástasis ganglionares regionales. El mapeo linfático y biopsia del ganglio centinela (MLBGC) ha sido exitosamente utilizado para evaluar la presencia de metástasis ganglionares subclínicas en diversos tumores. bjetivo: Evaluar la utilidad de la técnica del MLBGC en los pacientes con CEC de alto riesgo para detectar la presencia de metástasis ganglionares regionales subclínicas. Material y métodos: De enero 2002 a marzo 2004, un total de 20 pacientes con CEC de alto riesgo con ganglios linfáticos regionales clínicamente no palpables fue evaluado con linfografía preoperatoria y MLBGC. Resultados: En 1 de cada 5 pacientes (20 %), el ganglio centinela reveló la presencia de micrometástasis. Ningún paciente con GC negativo manifestó progresión tumoral ganglionar regional durante un seguimiento medio de 23.5 meses (rango de 7 a 44 meses). Conclusiones: El MLBGC fue técnicamente posible con baja morbilidad. El MLBGC puede tener un importante papel en el tratamiento de los pacientes con CEC de alto riesgo con ganglios linfáticos regionales no palpables. Esta técnica puede ayudar a identificar los pacientes con metástasis en los ganglios linfáticos regionales que pueden beneficiarse de una disección ganglionar radical. Además provee importante información para utilizar terapias adyuvantes a la cirugía.
BACKGROUND: Some sub-groups of cutaneous squamous cell carcinoma (CSCC) display a higher risk for regional metastasis. Sentinel lymph node staging has been used successfully to evaluate nodal metastasis in selective tumors. OBJECTIVE: Assess the feasibility of sentinel node to detect occult regional lymph node metastasis in high-risk CSCC. MATERIAL AND METHODS: Between January 2002 and March 2004, a total of 20 patients received pre-operative lymphoscintigraphy and sentinel lymphadenectomy for high-risk CSCC with clinically non-palpable regional lymph nodes. RESULTS: In one of each 5 patients (20%), sentinel lymph node showed histological evidence of microinvolvement. No patients with negative sentinel node showed tumor dissemination during follow-up, with a mean of 23.5 months (range 7-44). CONCLUSIONS: Sentinel lymph node biopsy is technically feasible with low morbidity. Sentinel lymphadenectomy may play an important role in the management of high-risk CSCC with clinically non-palpable regional lymph nodes. This technique can help identify patients with regional lymph node metastases who may benefit from complete lymphadenectomy. This improved staging may allow clinicians to better stratify patients who might benefit from adjuvant therapy.