RESUMEN
Mismatch repair (MMR) deficiency has been linked to thiopurine resistance and hypermutation in relapsed acute lymphoblastic leukemia (ALL). However, the repair mechanism of thiopurine-induced DNA damage in the absence of MMR remains unclear. Here, we provide evidence that DNA polymerase ß (POLB) of base excision repair (BER) pathway plays a critical role in the survival and thiopurine resistance of MMR-deficient ALL cells. In these aggressive resistant ALL cells, POLB depletion and its inhibitor oleanolic acid (OA) treatment result in synthetic lethality with MMR deficiency through increased cellular apurinic/apyrimidinic (AP) sites, DNA strand breaks and apoptosis. POLB depletion increases thiopurine sensitivities of resistant cells, and OA synergizes with thiopurine to kill these cells in ALL cell lines, patient-derived xenograft (PDX) cells and xenograft mouse models. Our findings suggest BER and POLB's roles in the process of repairing thiopurine-induced DNA damage in MMR-deficient ALL cells, and implicate their potentials as therapeutic targets against aggressive ALL progression.
Asunto(s)
ADN Polimerasa beta , Leucemia-Linfoma Linfoblástico de Células Precursoras , Animales , Humanos , Ratones , Daño del ADN , ADN Polimerasa beta/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Mutaciones Letales Sintéticas , Reparación de la Incompatibilidad de ADN/genéticaRESUMEN
Two new polypeptides were isolated and purified from the extract of deer bone (constitutive part of Cucumis and Cervus polypeptide injection) by various column chromatography including C4 300Å and Sephadex G-50, as well as semipreparative HPLC. Their N-terminal amino acid sequences were identified by De Novo sequencing on the basis of MALDI-TOF-MS data and Explorer™ software. The N-terminal amino acid sequences of polypeptides were identified as NH2-Gly-Pro-Val-Gly-Pro-Thr-Gly-Pro-Val-Gly-Ala-Ala-Gly-Pro-Ser-Gly-Pro-Asp (Mei18 peptide, 1) and NH2-Ala-Gly-Pro-Ala-Gly-Pro-Leu-Gly-Pro-Leu-Gly-Pro-Leu-Gly-Pro-Leu-Gly-Pro-Pro-Asp-Ser-Try-Asp (Mei23 peptide, 2), respectively. Mei18 and Mei 23 peptides are new polypeptides.
Asunto(s)
Huesos/química , Ciervos , Materia Medica/química , Péptidos/química , Secuencia de Aminoácidos , Animales , Espectrometría de MasasRESUMEN
A high quantum yield (4.3%) hybrid nanogel system based on engineered polypeptides and Ag2S quantum dots has been developed as a multifunctional diagnostic and therapeutic agent for targeted second near-infrared fluorescence, photoacoustic imaging, and photothermal therapy.
Asunto(s)
Geles/química , Nanoestructuras/química , Imagen Óptica , Péptidos/química , Técnicas Fotoacústicas , Ingeniería de Proteínas , Puntos Cuánticos , Compuestos de Plata/química , Fluorescencia , Células HeLa , Humanos , Células MCF-7 , Tamaño de la Partícula , Fototerapia , Teoría Cuántica , Propiedades de SuperficieRESUMEN
A facile method for in situ fabrication of three-dimensional gold nanoparticle micropatterns in a cell-resistant polyethylene glycol hydrogel has been developed by combining photochemical synthesis of gold nanoparticles with photolithography technology. The gold nanoparticle micropatterns were further bio-modified with cell integrated polypeptide NcysBRGD based on a gold-thiol bond to improve cell behaviors. Primary cell tests showed that NcysBRGD can enhance cell adhesion very well on the surface of gold nanoparticle micropatterns.
Asunto(s)
Oro/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Nanopartículas del Metal/química , Péptidos/química , Secuencia de Aminoácidos , Materiales Biocompatibles/química , Adhesión Celular , Diseño de Equipo , Células HeLa , Humanos , Nanopartículas del Metal/ultraestructura , Microtecnología , Datos de Secuencia Molecular , Compuestos de Sulfhidrilo/química , Análisis de Matrices Tisulares/instrumentaciónRESUMEN
Quantum dot (QD)-polypeptide probes have been developed through the specific metal-affinity interaction between polypeptides appended with N-terminal polyhistidine sequences and CdSe/ZnS core-shell QDs. The size and charge of a QD-polypeptide can be tuned by using different coiled-coil polypeptides. Compared to glutathione-capped QDs (QD-GSH), QD-polypeptide probes showed an approximately two- to three-fold luminescence increase, and the luminescence increase was not obviously related to the charge of the polypeptide. QD-polypeptide probes with different charge have a great effect on nonspecific cellular uptake. QD-polypeptide probes with negative charge exhibited lower nonspecific cellular uptake in comparison to the QD-GSH, while positively charged QD-polypeptide probes presented higher cellular uptake than the QD-GSH. A targeted QD-ARGD probe can obviously increase targeted cellular uptake in α v ß 3 overexpressing HeLa cells compared to QD-A. In addition, QD-polypeptide probes showed lower in vitro cytotoxicity compared to the original QDs. These results demonstrate that these QD-polypeptide probes with high specific cellular uptake, high fluorescence intensity and low background noise are expected to have great potential applications in targeted cell imaging.