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1.
Cancer Control ; 30: 10732748231175256, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37148308

RESUMEN

PURPOSE: Identifying actionable oncogenic mutations have changed the therapeutic landscape in different types of tumors. This study investigated the utility of comprehensive genomic profiling (CGP), a hybrid capture-based next-generation sequencing (NGS) assay, in clinical practice in a developing country. METHODS: In this retrospective cohort study, CGP was performed on clinical samples from patients with different solid tumors recruited between December 2016 and November 2020, using hybrid capture-based genomic profiling, at the individual treating physicians' request in the clinical care for therapy decisions. Kaplan-Meier survival curves were estimated to characterize the time-to-event variables. RESULTS: Patients median age was 61 years (range: 14-87 years), and 64.7% were female. The most common histological diagnosis was lung primary tumors, with 90 patients corresponding to 52.9% of the samples (95% CI 45.4-60.4%). Actionable mutations with FDA-approved medications for specific alterations correspondent to tumoral histology were identified in 58 cases (46.4%), whereas other alterations were detected in 47 different samples (37.6%). The median overall survival was 15.5 months (95% CI 11.7 months-NR). Patients who were subjected to genomic evaluation at diagnosis reached a median overall survival of 18.3 months (95% CI 14.9 months-NR) compared to 14.1 months (95% CI 11.1 months-NR) in patients who obtained genomic evaluation after tumor progression and during standard treatment (P = .7). CONCLUSION: CGP of different types of tumors identifies clinically relevant genomic alterations that have benefited from targeted therapy and improve cancer care in a developing country to guide personalized treatment to beneficial outcomes of cancer patients.


Asunto(s)
Países en Desarrollo , Neoplasias Pulmonares , Humanos , Femenino , Persona de Mediana Edad , Masculino , Estudios Retrospectivos , Neoplasias Pulmonares/patología , Mutación , Genómica , Secuenciación de Nucleótidos de Alto Rendimiento
2.
Target Oncol ; 18(3): 425-440, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37017806

RESUMEN

BACKGROUND: Epidermal growth factor receptor (EGFR) mutations (EGFRm) represent one of the most common genomic alterations identified among patients with non-small cell lung cancer (NSCLC). Several targeted agents for patients with EGFRm have been proven safe and effective, including the third-generation tyrosine kinase inhibitor (TKI) osimertinib. Nonetheless, some patients will present with or develop EGFR-TKI resistance mechanisms. OBJECTIVE: We characterized the genomic landscape of primary resistance to osimertinib among Hispanic patients with EGFR-mutant NSCLC. METHODS: An observational longitudinal cohort study was conducted with two groups of patients, those with intrinsic resistance (cohort A) and those with long-term survival (cohort B). All patients were treated and followed between January 2018 and May 2022. All patients were assessed for Programmed Cell Death Ligand 1 (PD-L1) expression and Bcl-2-like protein 11 (BIM)/AXL mRNA expression before starting TKI. After 8 weeks of treatment, a liquid biopsy was performed to determine the presence of circulating free DNA (cfDNA), and next-generation sequencing (NGS) was used to identify mutations at the time of progression. In both cohorts, overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated. RESULTS: We found a homogeneous distribution of EGFR-sensitizing mutations in both cohorts. For cohort A, exon 21 mutations were more common than exon 19 deletions (ex19dels) for cohort B (P = 0.0001). The reported ORR for osimertinib was 6.3% and 100% for cohorts A and B, respectively (P = 0.0001). PFS was significantly higher in cohort B (27.4 months vs. 3.1 months; P = 0.0001) and ex19del patients versus L858R (24.5 months, 95% confidence interval [CI] 18.2-NR), vs. 7.6 months, 95% CI 4.8-21.1; P = 0.001). OS was considerably lower for cohort A (20.1 months vs. 36.0 months; P = 0.0001) and was better for patients with ex19del, no brain metastasis, and low tumor mutation burden. At the time of progression, more mutations were found in cohort A, identifying off-target alterations more frequently, including TP53, RAS, and RB1. CONCLUSION: EGFR-independent alterations are common among patients with primary resistance to osimertinib and significantly impact PFS and OS. Our results suggest that among Hispanic patients, other variables associated with intrinsic resistance include the number of commutations, high levels AXL mRNA, and low levels of BIM mRNA, T790M de novo, EGFR p.L858R presence, and a high tumoral mutational burden.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Ácidos Nucleicos Libres de Células , Neoplasias Pulmonares , Humanos , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Estudios Longitudinales , Receptores ErbB/genética , Receptores ErbB/metabolismo , Mutación , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Compuestos de Anilina/farmacología , Compuestos de Anilina/uso terapéutico , Estudios de Cohortes , Genómica , Hispánicos o Latinos
3.
Lung Cancer ; 170: 114-121, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35753125

RESUMEN

BACKGROUND: Mutations in STK11 (STK11Mut) and, frequently co-occurring, KEAP1 mutations (KEAP1Mut) are associated with poor survival in metastatic Non-small Cell Lung Cancer (mNSCLC) patients treated with immunotherapy. However, there are limited data regarding the prognostic or predictive significance of these genomic alterations among Hispanics. METHODS: This retrospective study analyzed a cohort of Hispanic patients (N = 103) diagnosed with mNSCLC from the US and seven Latin American countries (LATAM) treated with immune checkpoint inhibitors (ICI) alone or in combination as first-line (Cohort A). All cases were treated in routine care between January 2016 and December 2021. The main objectives were to determine the association of mutations in STK11 or KEAP1 in these patients' tumors with overall (OS) and progression-free survival (PFS), presence of KRAS mutations, tumor mutational burden (TMB), and other relevant clinical variables. To compare outcomes with a STK11Wt/KEAP1Wt population, historical data from a cohort of Hispanic patients (N = 101) treated with first-line ICI was used, matching both groups by country of origin, gender, and Programed Death-ligand 1 (PD-L1) expression level (Cohort B). RESULTS: Most tumors had mutations only in STK11 or KEAP1 (45.6%) without KRAS co-mutation or any other genomic alteration. Besides, 35%, 8.7%, 6.8%, and 3.9% were KRASMut + STK11Mut, KRASMut + STK11Mut + KEAP1Mut, STK11Mut + KEAP1Mut, and KRASMut + KEAP1Mut, respectively. Based on KRAS status, STK11 alterations were associated with significantly lower PD-L1 expression among those with KRASWt (p = 0.023), whereas KEAP1 mutations were predominantly associated with lower PD-L1 expression among KRASMut cases (p = 0.047). Tumors with KRASMut + KEAP1Mut had significantly higher median TMB when compared to other tumors (p = 0.040). For Cohort A, median PFS was 4.9 months (95%CI 4.3-5.4), slightly longer in those with KEAP1mut 6.1 months versus STK11Mut 4.7 months (p = 0.38). In the same cohort, PD-L1 expression and TMB did not influence PFS. OS was significantly longer among patients with tumors with PD-L1 ≥ 50% (30.9 months), and different from those with PD-L1 1-49% (22.0 months), and PD-L1 < 1% (12.0 months) (p = 0.0001). When we compared the cohorts A and B, OS was significantly shorter for patients carrying STK1 [STK11Mut 14.2 months versus STK11Wt 27.0 months (p = 0.0001)] or KEAP1 [KEAP1Mut 12.0 months versus KEAP1Wt 24.4 months (p = 0.005)] mutations. PD-L1 expression significantly affected OS independently of the presence of mutations in STK11, KEAP1, or KRAS. TMB-H favored better OS. CONCLUSIONS: This is the first large Hispanic cohort to study the impact of STK11 and KEAP1 mutations in NSCLC patient treated with ICI. Our data suggest that mutations in the above-mentioned genes are associated with PD-L1 expression levels and poor OS.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Quinasas de la Proteína-Quinasa Activada por el AMP , Antígeno B7-H1/genética , Biomarcadores de Tumor/genética , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Hispánicos o Latinos/genética , Humanos , Proteína 1 Asociada A ECH Tipo Kelch/genética , Neoplasias Pulmonares/patología , Mutación , Factor 2 Relacionado con NF-E2/genética , Pronóstico , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Sistema de Registros , Estudios Retrospectivos
4.
JCO Precis Oncol ; 5: 839-848, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34994616

RESUMEN

PURPOSE: BIM activation is essential for epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI)-triggered apoptosis in EGFR-mutant non-small-cell lung cancer (NSCLC). A deletion in the intron two of the BIM gene results in generation of alternatively spliced isoforms that impairs their apoptotic response to TKIs, conferring the NSCLC cells intrinsic resistance to these medications. Patients with both alterations have poor clinical evolution. The current study aimed to investigate the clinical efficacy and tolerability of EGFR-TKIs plus bevacizumab (Bev) versus EGFR-TKIs alone as first-line treatment in advanced NSCLC patients with EGFR mutations and BIM deletions (BIMdel). MATERIALS AND METHODS: A retrospective analysis was conducted. BIMdel was detected using polymerase chain reaction analysis and direct sequencing of DNA. BIM protein expression was investigated by immunohistochemistry, and BIM mRNA levels by reverse transcriptase-polymerase chain reaction. Clinical characteristics, overall survival, progression-free survival (PFS), overall response rate (ORR), and treatment-related adverse events were compared between both groups. RESULTS: Thirty-three patients were included; 15 received EGFR-TKIs, and 18 received EGFR-TKIs plus Bev. The median age was 63 years, with a majority of recruited female patients. All included individuals had an Eastern Cooperative Oncology Group performance score of 2 or less. The addition of Bev resulted in a significantly higher ORR (94.4% v 40%, P > .001). Median PFS was longer with the use of the combination therapy (11.12 v 7.87 months; P = .001). Median overall survival tended to be longer in the EGFR-TKIs plus Bev (30.9 v 25.4 months; P = .06) but failed to reach statistical significance. Response in terms of both partial and complete as well as overall favorably affected PFS. CONCLUSION: EGFR-TKIs plus Bev conferred a significantly higher ORR and PFS in advanced NSCLC patients with EGFR mutation and BIMdel. Further prospective studies are needed to validate these findings.


Asunto(s)
Antineoplásicos Inmunológicos/uso terapéutico , Proteína 11 Similar a Bcl2/genética , Bevacizumab/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Receptores ErbB/genética , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Adulto , Anciano , Carcinoma de Pulmón de Células no Pequeñas/patología , Combinación de Medicamentos , Receptores ErbB/antagonistas & inhibidores , Femenino , Eliminación de Gen , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Mutación , Estadificación de Neoplasias , Polimorfismo Genético , Estudios Retrospectivos , Adulto Joven
5.
Artículo en Inglés | MEDLINE | ID: mdl-32266169

RESUMEN

Following the injection of Plasmodium sporozoites by a female Anopheles mosquito into the dermis, they become engaged on a long journey to hepatic tissue where they must migrate through different types of cell to become established in parasitophorous vacuoles in hepatocytes. Studies have shown that proteins such as cell traversal protein for Plasmodium ookinetes and sporozoites (CelTOS) play a crucial role in cell-traversal ability. Although CelTOS has been extensively studied in various species and included in pre-clinical assays it remains unknown which P. vivax CelTOS (PvCelTOS) regions are key in its interaction with traversed or target cells (Kupffer or hepatocytes) and what type of pressure, association and polymorphism these important regions could have to improve their candidacy as important vaccine antigens. This work has described producing a recombinant PvCelTOS which was recognized by ~30% P. vivax-infected individuals, thereby confirming its ability for inducing a natural immune response. PvCelTOS' genetic diversity in Colombia and its ability to interact with HeLa (traversal cell) and/or HepG2 cell (target cell) external membrane have been assessed. One region in the PvCelTOS amino-terminal region and another in its C-terminus were seen to be participating in host-pathogen interactions. These regions had important functional constraint signals (ω < 0.3 and several sites under negative selection) and were able to inhibit specific rPvCelTOS binding to HeLa cells. This led to suggesting that sequences between aa 41-60 (40833) and 141-160 (40838) represent promising candidates for an anti-P. vivax subunit-based vaccine.


Asunto(s)
Plasmodium vivax , Esporozoítos , Animales , Antígenos de Protozoos/genética , Colombia , Femenino , Células HeLa , Interacciones Huésped-Patógeno , Humanos , Proteínas Protozoarias/genética
6.
Front Oncol ; 10: 588932, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33384957

RESUMEN

BACKGROUND: Lung cancer is a public health problem, and squamous cell carcinoma (SCC) is the second most prevalent subtype of this neoplasm. Compared to other subtypes, including adenocarcinoma, SCC is less well understood in terms of molecular pathogenesis, limiting therapeutic options among targeted agents approved for other disease subgroups. In this study, we sought to characterize the SCC genomic profile using a validated Next Generation Sequencing (NGS) platform. METHODS: The comprehensive NGS assay (TruSight Tumor 170) was used in order to target the full coding regions of 170 cancer-related genes on SCC samples. PD-L1 expression in tumor cells (TCs) was assessed using clone 22C3 (Dako). Clinical outcomes were correlated with molecular profile, including progression free survival (PFS), overall response rate (ORR), and overall survival (OS). RESULTS: A total of 26 samples were included, median age was 67 years (r, 33-83) and 53.8% were men. Tobacco consumption was identified in all subjects (mean 34-year package). For first-line treatment 80.8% of patients received cisplatin or carboplatin plus gemcitabine. In terms of molecular profile, we identified a high prevalence of inactivating mutations in TP53 (61.5%), PIK3CA (34.6%), MLL2 (34.6%), KEAP1 (38.4%), and NOTCH1 (26.9%). PD-L1 expression ranged from negative, 1, 2-49, and ≥50% in 23.1, 38.5, 26.9, and 11.5%, respectively. Interestingly, the genetic alterations did not have an effect in PFS, OS or ORR in this study. However, PDL1 expression was higher among those who had mutations in TP53 (p = 0.037) and greater expression of PDL1 was related to PIK3CA alterations (p = 0.05). CONCLUSIONS: The genomic profile of SCC encompasses important genes including TP53, PIK3CA and KEAP1. TP53 mutations could be associated with PDL1 expression, generating hypothesis regarding specific treatment options.

7.
Biomed Res Int ; 2019: 8680935, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31111070

RESUMEN

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb, i.e., the aetiological agent); the WHO has established this disease as high priority due to its ensuing mortality. Mtb uses a range of mechanisms for preventing its elimination by an infected host; new, viable alternatives for blocking the host-pathogen interaction are thus sought constantly. This article updates our laboratory's systematic search for antigens using bioinformatics tools to clarify the Mtb H37Rv Rv3632 protein's topology and location. This article reports a C-terminal region consisting of peptides 39255 and 39256 (81Thr-Arg114) having high specific binding regarding two infection-related cell lines (A549 and U937); they inhibited mycobacterial entry to U937 cells in a concentration-dependent manner. Rv3632 forms part of the mycobacterial cell envelope, formed by six linear synthetic peptides. Circular dichroism enabled determining the protein's secondary structure. It was also found that peptide 39254 (61Gly-Thr83) was a HABP for alveolar epithelial cells and inhibited mycobacteria entry to these cells regardless of concentration. Sera from active or latent tuberculosis patients did not recognise HABPs 39254 and 39256. These sequences represent a promising approach aiming at their ongoing modification and for including them when designing a multi-epitope, anti-tuberculosis vaccine.


Asunto(s)
Proteínas Bacterianas/química , Mycobacterium tuberculosis/metabolismo , Péptidos/química , Unión Proteica , Células A549 , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Membrana Celular/química , Pared Celular/química , Dicroismo Circular , Biología Computacional , Interacciones Huésped-Patógeno , Humanos , Modelos Moleculares , Mycobacterium tuberculosis/genética , Péptidos/aislamiento & purificación , Estructura Secundaria de Proteína , Transcripción Genética , Células U937
8.
Malar J ; 17(1): 301, 2018 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-30126427

RESUMEN

Understanding the life cycle of Plasmodium vivax is fundamental for developing strategies aimed at controlling and eliminating this parasitic species. Although advances in omic sciences and high-throughput techniques in recent years have enabled the identification and characterization of proteins which might be participating in P. vivax invasion of target cells, exclusive parasite tropism for invading reticulocytes has become the main obstacle in maintaining a continuous culture for this species. Such advance that would help in defining each parasite protein's function in the complex process of P. vivax invasion, in addition to evaluating new therapeutic agents, is still a dream. Advances related to maintenance, culture medium supplements and the use of different sources of reticulocytes and parasites (strains and isolates) have been made regarding the development of an in vitro culture for P. vivax; however, only some cultures having few replication cycles have been obtained to date, meaning that this parasite's maintenance goes beyond the technical components involved. Although it is still not yet clear which molecular mechanisms P. vivax prefers for invading young CD71+ reticulocytes [early maturation stages (I-II-III)], changes related to membrane proteins remodelling of such cells could form part of the explanation. The most relevant aspects regarding P. vivax in vitro culture and host cell characteristics have been analysed in this review to explain possible reasons why the species' continuous in vitro culture is so difficult to standardize. Some alternatives for P. vivax in vitro culture have also been described.


Asunto(s)
Técnicas Microbiológicas/métodos , Parasitología/métodos , Plasmodium vivax/crecimiento & desarrollo , Animales , Medios de Cultivo/química , Reticulocitos/parasitología
9.
Cell Microbiol ; 20(7): e12835, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29488316

RESUMEN

Elucidating receptor-ligand and protein-protein interactions represents an attractive alternative for designing effective Plasmodium vivax control methods. This article describes the ability of P. vivax rhoptry neck proteins 2 and 4 (RON2 and RON4) to bind to human reticulocytes. Biochemical and cellular studies have shown that two PvRON2- and PvRON4-derived conserved regions specifically interact with protein receptors on reticulocytes marked by the CD71 surface transferrin receptor. Mapping each protein fragment's binding region led to defining the specific participation of two 20 amino acid-long regions selectively competing for PvRON2 and PvRON4 binding to reticulocytes. Binary interactions between PvRON2 (ligand) and other parasite proteins, such as PvRON4, PvRON5, and apical membrane antigen 1 (AMA1), were evaluated and characterised by surface plasmon resonance. The results revealed that both PvRON2 cysteine-rich regions strongly interact with PvAMA1 Domains II and III (equilibrium constants in the nanomolar range) and at a lower extent with the complete PvAMA1 ectodomain and Domains I and II. These results strongly support that these proteins participate in P. vivax's complex invasion process, thus providing new pertinent targets for blocking P. vivax merozoites' specific entry to their target cells.


Asunto(s)
Antígenos CD/metabolismo , Adhesión Celular , Interacciones Huésped-Patógeno , Plasmodium vivax/fisiología , Proteínas Protozoarias/metabolismo , Receptores de Transferrina/metabolismo , Reticulocitos/parasitología , Humanos , Unión Proteica , Mapeo de Interacción de Proteínas , Resonancia por Plasmón de Superficie
10.
Malar J ; 17(1): 76, 2018 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-29422046

RESUMEN

BACKGROUND: The Plasmodium vivax Duffy binding protein (PvDBP) has been the most studied ligand binding human reticulocytes to date. This molecule has a cysteine-rich domain in region II (RII) which has been used as control for evaluating the target cell binding activity of several parasite molecules. However, obtaining rPvDBP-RII in a soluble form using the Escherichia coli expression system usually requires laborious and time-consuming steps for recovering the molecule's structure and function, considering it is extracted from inclusion bodies. The present study describes an easy and fast method for expressing and obtaining several PvDBP fragments which should prove ideal for use in protein-cell interaction assays. RESULTS: Two PvDBP encoding regions (rii and riii/v) were cloned in pEXP5-CT vector and expressed in E. coli and extracted from the soluble fraction (rPvDBP-RIIS and rPvDBP-RIII/VS) using a simple freezing/thawing protocol. After the purification, dichroism analysis enabled verifying high rPvDBP-RIIS and rPvDBP-RIII/VS secondary structure α-helix content, which was lowered when molecules were extracted from inclusion bodies (rPvDBP-RIIIB and rPvDBP-RIII/VIB) using a denaturing step. Interestingly, rPvDBP-RIIS, but not rPvDBP-RIIIB, bound to human reticulocytes, while rPvDBP-RIII/VS and rPvDBP-RIII/VIB bound to such cells in a similar way to negative control (cells incubated without recombinant proteins). CONCLUSIONS: This research has shown for the first time how rPvDBP-RII can be expressed and obtained in soluble form using the E. coli system and avoiding the denaturation and refolding steps commonly used. The results highlight the usefulness of the rPvDBP-RIII/VS fragment as a non-binding control for protein-cell target interaction assays. The soluble extraction protocol described is a good alternative to obtain fully functional P. vivax proteins in a fast and easy way, which will surely prove useful to laboratories working in studying this parasite's biology.


Asunto(s)
Antígenos de Protozoos/genética , Antígenos de Protozoos/aislamiento & purificación , Perfilación de la Expresión Génica/métodos , Parasitología/métodos , Plasmodium vivax/genética , Proteínas Protozoarias/genética , Proteínas Protozoarias/aislamiento & purificación , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/aislamiento & purificación , Reticulocitos/metabolismo
11.
Sci Rep ; 7(1): 9616, 2017 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-28855657

RESUMEN

The malarial parasite's invasion is complex, active and coordinated, involving many low and high affinity interactions with receptors on target cell membrane. Proteomics analysis has described around 40 proteins in P. vivax which could be involved in reticulocyte invasion; few have been studied with the aim of elucidating how many of them establish specific interactions with their respective host cells. Given the importance of knowing which of the parasite's protein regions are functionally important for invasion, minimum regions mediating specific interaction between Plasmodium vivax apical membrane antigen 1 (PvAMA-1) and its host cell were here elucidated. The region covering PvAMA-1 domains I and II (PvAMA-DI-II) specifically bound to the CD71+ red blood cell subpopulation. A 20 residue-long region (81EVENAKYRIPAGRCPVFGKG100) located in domain I was capable of inhibiting PvAMA-DI-II recombinant protein binding to young reticulocytes (CD71+CD45-) and rosette formation. This conserved peptide specifically interacted with high affinity with reticulocytes (CD71+) through a neuraminidase- and chymotrypsin-treatment sensitive receptor. Such results showed that, despite AMA-1 having universal functions during late Plasmodium invasion stages, PvAMA-1 had reticulocyte-preferring binding regions, suggesting that P. vivax target cell selection is not just restricted to initial interactions but maintained throughout the erythrocyte invasion cycle, having important implications for designing a specific anti-P. vivax vaccine.


Asunto(s)
Antígenos CD/metabolismo , Antígenos de Protozoos/química , Antígenos de Protozoos/metabolismo , Eritrocitos/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/metabolismo , Plasmodium vivax/fisiología , Dominios y Motivos de Interacción de Proteínas , Proteínas Protozoarias/química , Proteínas Protozoarias/metabolismo , Receptores de Transferrina/metabolismo , Secuencia de Aminoácidos , Animales , Antígenos CD/química , Línea Celular , Secuencia Conservada , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Malaria Vivax/metabolismo , Malaria Vivax/parasitología , Modelos Moleculares , Unión Proteica , Conformación Proteica , Receptores de Superficie Celular/metabolismo , Receptores de Transferrina/química , Relación Estructura-Actividad
12.
Malar J ; 14: 106, 2015 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-25888962

RESUMEN

BACKGROUND: Different proteins derived from the membrane or the apical organelles become involved in malarial parasite invasion of host cells. Among these, the rhoptry neck proteins (RONs) interact with a protein component of the micronemes to enable the formation of a strong bond which is crucial for the parasite's successful invasion. The present study was aimed at identifying and characterizing the RON5 protein in Plasmodium vivax and evaluating its ability to bind to reticulocytes. METHODS: Taking the Plasmodium falciparum and Plasmodium knowlesi RON5 amino acid sequences as template, an in-silico search was made in the P. vivax genome for identifying the orthologous gene. Different molecular tools were used for experimentally ascertaining pvron5 gene presence and transcription in P. vivax VCG-1 strain schizonts. Polyclonal antibodies against PvRON5 peptides were used for evaluating protein expression (by Western blot) and sub-cellular localization (by immunofluorescence). A 33 kDa PvRON5 fragment was expressed in Escherichia coli and used for evaluating the reactivity of sera from patients infected by P. vivax. Two assays were made for determining the RON5 recombinant fragment's ability to bind to reticulocyte-enriched human umbilical cord samples. RESULTS: The pvron5 gene (3,477 bp) was transcribed in VCG-1 strain schizonts and encoded a ~133 kDa protein which was expressed in the rhoptry neck of VCG-1 strain late schizonts, together with PvRON2 and PvRON4. Polyclonal sera against PvRON5 peptides specifically detected ~85 and ~30 kDa fragments in parasite lysate, thereby suggesting proteolytic processing in this protein. Comparative analysis of VCG-1 strain PvRON5 with other P. vivax strains having different geographic localizations suggested its low polymorphism regarding other malarial antigens. A recombinant fragment of the PvRON5 protein (rPvRON5) was recognized by sera from P. vivax-infected patients and bound to red blood cells, having a marked preference for human reticulocytes. CONCLUSIONS: The pvron5 gene is transcribed in the VCG-1 strain, the encoded protein is expressed at the parasite's apical pole and might be participating in merozoite invasion of host cells, taking into account its marked binding preference for human reticulocytes.


Asunto(s)
Plasmodium vivax/genética , Proteínas Protozoarias/genética , Reticulocitos/parasitología , Humanos , Datos de Secuencia Molecular , Plasmodium vivax/crecimiento & desarrollo , Plasmodium vivax/metabolismo , Unión Proteica , Proteínas Protozoarias/química , Proteínas Protozoarias/metabolismo , Reticulocitos/metabolismo , Esquizontes/crecimiento & desarrollo , Esquizontes/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN
13.
Rev. mex. radiol ; 50(4): 145-9, oct.-dic. 1996. ilus
Artículo en Español | LILACS | ID: lil-187780

RESUMEN

Informamos el caso clínico de un adolescente del sexo masculino, quien presentaba como síntomas principales epistaxis recurrente y obstrucción nasal izquierda. El paciente recibió tratamiento médico, previo al diagnóstico definitivo, sin mejoría. Con la resonancia magnética se hizo el diagnóstico de tumor de nasofaringe con extensión al seno cavernoso. Se realizó angiografía y embolización preoperatoria. Los estudios de tomografía axial computada, de control, ralizados a los 12 días y a los 9 meses después de la cirugía, mostraron masa tumoral residual


Asunto(s)
Humanos , Masculino , Adolescente , Angiografía , Tomografía , Nariz/patología , Angiofibroma/diagnóstico , Angiofibroma , Embolización Terapéutica , Radiología Intervencionista , Espectroscopía de Resonancia Magnética
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