RESUMO
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.
Assuntos
DNA Polimerase beta , Leucemia-Linfoma Linfoblástico de Células Precursoras , Animais , Humanos , Camundongos , Dano ao DNA , DNA Polimerase beta/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Mutações Sintéticas Letais , Reparo de Erro de Pareamento de DNA/genéticaRESUMO
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.
Assuntos
Osso e Ossos/química , Cervos , Materia Medica/química , Peptídeos/química , Sequência de Aminoácidos , Animais , Espectrometria de MassasRESUMO
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.
Assuntos
Géis/química , Nanoestruturas/química , Imagem Óptica , Peptídeos/química , Técnicas Fotoacústicas , Engenharia de Proteínas , Pontos Quânticos , Compostos de Prata/química , Fluorescência , Células HeLa , Humanos , Células MCF-7 , Tamanho da Partícula , Fototerapia , Teoria Quântica , Propriedades de SuperfícieRESUMO
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.
Assuntos
Ouro/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Nanopartículas Metálicas/química , Peptídeos/química , Sequência de Aminoácidos , Materiais Biocompatíveis/química , Adesão Celular , Desenho de Equipamento , Células HeLa , Humanos , Nanopartículas Metálicas/ultraestrutura , Microtecnologia , Dados de Sequência Molecular , Compostos de Sulfidrila/química , Análise Serial de Tecidos/instrumentaçãoRESUMO
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.