RESUMEN
Multidrug resistance MDR proteins (MRPs) are members of the C family of a group of proteins named ATP binding cassette (ABC) transporters. MRPs can transport drugs including anticancer drugs, nucleoside analogs, antimetabolites and tyrosine kinase inhibitors. Drugs used in HCC therapy, such as tyrosine kinase inhibitor sorafenib, are substrates of uptake and/or efflux transporters. Variable expression of MRPs at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. Recently, we reported that the hepatocyte SLAMF3 expression (Signaling Lymphocytic Activation Molecule Family member 3) was reduced in tumor cells from hepatocellular carcinoma (HCC) compared to its high expression in adjacent tissues. In the present study, we make a strong correlation between induced SLAMF3 overexpression and the specific loss of MRP-1 expression and its functionalities as a drugs resistance transporter. No changes were observed on expression of ABCG2 and MDR. More importantly, we highlight a strong inverse correlation between MRP-1 and SLAMF3 expression in patients with HCC. We propose that the SLAMF3 overexpression in cancerous cells could represent a potential therapeutic strategy to improve the drugs sensibility of resistant cells and thus control the therapeutic failure in HCC patients.
Asunto(s)
Antineoplásicos/uso terapéutico , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Hepatocitos/metabolismo , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Familia de Moléculas Señalizadoras de la Activación Linfocitaria/metabolismo , Anciano , Anciano de 80 o más Años , Antineoplásicos/farmacología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Resistencia a Antineoplásicos , Femenino , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Familia de Moléculas Señalizadoras de la Activación Linfocitaria/genética , TransfecciónRESUMEN
We have identified a deletion of 125 bp (α-α(Δ125)) (NG_000006.1: g.37040_37164del) in the α-globin gene cluster in a Kabyle population. A combination of singlex and multiplex polymerase chain reaction (PCR)-based assays have been used to identify the molecular defect. Sequencing of the abnormal PCR amplification product revealed a novel α1-globin promoter deletion. The endpoints of the deletion were characterized by sequencing the deletion junctions of the mutated allele. The observed deletion was located 378 bp upstream of the α1-globin gene transcription initiation site and leaves the α2 gene intact. In some patients, the α-α(Δ125) deletion was shown to segregate with Hb S (HBB: c.20A>T) and/or Hb C (HBB: c.19G>A) or a ß-thalassemic allele. The α-α(Δ125) deletion has no discernible effect on red cell indices when inherited with no other abnormal globin genes. The family study demonstrated that the deletion is heritable. This is the only example of an intergenic α2-α1 non coding DNA deletion, leaving the α2-globin gene and the α1 coding part intact.
Asunto(s)
Genética de Población , Eliminación de Secuencia , Globinas alfa/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Argelia , Secuencia de Bases , Niño , Preescolar , Análisis Mutacional de ADN , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Adulto JovenRESUMEN
Polo-like kinase PLK1 is a cell cycle protein that plays multiple roles in promoting cell cycle progression. Among the many roles, the most prominent role of PLK1 is to regulate the mitotic spindle formation checkpoint at the M-phase. Recently we reported the expression of SLAMF3 in Hepatocytes and show that it is down regulated in tumor cells of hepatocellular carcinoma (HCC). We also show that the forced high expression level of SLAMF3 in HCC cells controls proliferation by inhibiting the MAPK ERK/JNK and the mTOR pathways. In the present study, we provide evidence that the inhibitory effect of SLAMF3 on HCC proliferation occurs through Retinoblastoma (RB) factor and PLK1-dependent pathway. In addition to the inhibition of MAPK ERK/JNK and the mTOR pathways, expression of SLAMF3 in HCC retains RB factor in its hypophosphorylated active form, which in turn inactivates E2F transcription factor, thereby repressing the expression and activation of PLK1. A clear inverse correlation was also observed between SLAMF3 and PLK expression in patients with HCC. In conclusion, the results presented here suggest that the tumor suppressor potential of SLAMF3 occurs through activation of RB that represses PLK1. We propose that the induction of a high expression level of SLAMF3 in cancerous cells could control cellular mitosis and block tumor progression.
Asunto(s)
Carcinoma Hepatocelular/patología , Proteínas de Ciclo Celular/metabolismo , Neoplasias Hepáticas/patología , Mitosis/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Proteína de Retinoblastoma/metabolismo , Familia de Moléculas Señalizadoras de la Activación Linfocitaria/metabolismo , Anciano , Anciano de 80 o más Años , Línea Celular Tumoral , Proliferación Celular/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Quinasa Tipo Polo 1RESUMEN
Recent research has shown that chronic lymphocytic leukemia (CLL) B-cells display a strong tendency to differentiate into antibody-secreting cells (ASCs) and thus may be amenable to differentiation therapy. However, the effect of this differentiation on factors associated with CLL pathogenesis has not been reported. In the present study, purified CLL B-cells were stimulated to differentiate into ASCs by phorbol myristate acetate or CpG oligodeoxynucleotide, in combination with CD40 ligand and cytokines in a two-step, seven-day culture system. We investigated (i) changes in the immunophenotypic, molecular, functional, morphological features associated with terminal differentiation into ASCs, (ii) the expression of factors involved in CLL pathogenesis, and (iii) the expression of pro- and anti-apoptotic proteins in the differentiated cells. Our results show that differentiated CLL B-cells are able to display the transcriptional program of ASCs. Differentiation leads to depletion of the malignant program and deregulation of the apoptosis/survival balance. Analysis of apoptosis and the cell cycle showed that differentiation is associated with low cell viability and a low rate of cell cycle entry. Our findings shed new light on the potential for differentiation therapy as a part of treatment strategies for CLL.
Asunto(s)
Células Productoras de Anticuerpos/inmunología , Linfocitos B/inmunología , Diferenciación Celular/inmunología , Leucemia Linfocítica Crónica de Células B/inmunología , Células Productoras de Anticuerpos/efectos de los fármacos , Células Productoras de Anticuerpos/metabolismo , Apoptosis/efectos de los fármacos , Apoptosis/genética , Apoptosis/inmunología , Linfocitos B/efectos de los fármacos , Linfocitos B/metabolismo , Ligando de CD40/farmacología , Técnicas de Cultivo de Célula , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Ciclo Celular/inmunología , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/genética , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Supervivencia Celular/inmunología , Células Cultivadas , Citocinas/farmacología , Ensayo de Inmunoadsorción Enzimática , Expresión Génica/efectos de los fármacos , Expresión Génica/genética , Expresión Génica/inmunología , Humanos , Immunoblotting , Isotipos de Inmunoglobulinas/inmunología , Isotipos de Inmunoglobulinas/metabolismo , Inmunofenotipificación , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/inmunología , Proteínas Inhibidoras de la Apoptosis/metabolismo , Leucemia Linfocítica Crónica de Células B/genética , Leucemia Linfocítica Crónica de Células B/metabolismo , Factor de Unión 1 al Potenciador Linfoide/genética , Factor de Unión 1 al Potenciador Linfoide/inmunología , Factor de Unión 1 al Potenciador Linfoide/metabolismo , Oligodesoxirribonucleótidos/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Survivin , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
BACKGROUND: Heterozygous dominant mutations of PRRT2 have been associated with various types of paroxysmal neurological manifestations, including benign familial infantile convulsions and paroxysmal kinesigenic dyskinesia. The phenotype associated with biallelic mutations is not well understood as few cases have been reported. METHODS: PRRT2 screening was performed by Sanger sequencing and quantitative multiplex PCR of short fluorescent fragments. A CGH array was used to characterise the size of the deletion at the 16p11.2 locus. RESULTS: Five patients with homozygous or compound heterozygous deleterious PRRT2 gene mutations are described. These patients differ from those with a single mutation by their overall increased severity: (1) the combination of at least three different forms of paroxysmal neurological disorders within the same patient and persistence of paroxysmal attacks; (2) the occurrence of uncommon prolonged episodes of ataxia; and (3) the association of permanent neurological disorders including learning difficulties in four patients and cerebellar atrophy in 2. CONCLUSIONS: Our observations expand the phenotype related to PRRT2 insufficiency, and highlight the complexity of the phenotype associated with biallelic mutations, which represents a severe neurological disease with various paroxysmal disorders and frequent developmental disabilities.
Asunto(s)
Proteínas de la Membrana/genética , Mutación/genética , Proteínas del Tejido Nervioso/genética , Adolescente , Adulto , Factores de Edad , Alelos , Ataxia/genética , Atrofia/genética , Encefalopatías/genética , Niño , Preescolar , Corea/genética , Cromosomas Humanos Par 16/genética , Femenino , Eliminación de Gen , Genes/genética , Humanos , Lactante , Discapacidades para el Aprendizaje/genética , Masculino , Reacción en Cadena de la Polimerasa Multiplex , Fenotipo , Adulto JovenRESUMEN
Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole-exome sequencing, we identified the c.910C > T transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca(2+) sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca(2+) levels and store-operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single-gene defect, which is consistent with Mendelian-dominant inheritance.