RESUMEN
O6-methylguanine DNA methyltransferase (MGMT) is a crucial determinant of temozolomide (TMZ) sensitivity in patients with glioblastoma (GBM). The therapeutic potential of small interfering RNA (siRNA) targeting MGMT to enhance TMZ sensitivity has been hampered by serum nuclease degradation, off-target effects, poor accumulation at tumor sites, and low circulation in blood stream. In this study, we developed a framework nucleic acid-based nanoparticles (FNN), which is constructed from a six-helix DNA bundle, to encapsulate and protect siMGMT for improving TMZ sensitivity in GBM treatment. For better blood-brain barrier (BBB) penetration and GBM targeting, we conjugated Angiopep-2 (ANG) targeting modules to each end of the FNN. Nucleolin (NCL)-responsive locks were engineered along the sides of the six-helix DNA bundle, which safeguard siMGMT before tumor entry. Upon interaction with tumor-overexpressed NCL, these locks unlock, exposing siMGMT, this allows for effective suppression of MGMT, resulting in a significant improvement of TMZ therapeutic efficacy in GBM. This innovative strategy has the potential to transform the current treatment landscape for GBM.
Asunto(s)
Antineoplásicos Alquilantes , Barrera Hematoencefálica , Neoplasias Encefálicas , Glioblastoma , Nanopartículas , Temozolomida , Glioblastoma/tratamiento farmacológico , Glioblastoma/patología , Temozolomida/farmacología , Temozolomida/administración & dosificación , Temozolomida/uso terapéutico , Humanos , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/genética , Antineoplásicos Alquilantes/farmacología , Antineoplásicos Alquilantes/uso terapéutico , Nanopartículas/química , Animales , Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Línea Celular Tumoral , Proteínas de Unión al ARN/metabolismo , Enzimas Reparadoras del ADN/metabolismo , Enzimas Reparadoras del ADN/genética , Metilasas de Modificación del ADN/metabolismo , Nucleolina , Fosfoproteínas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas Supresoras de Tumor/genética , ARN Interferente Pequeño/administración & dosificación , Ácidos Nucleicos , PéptidosRESUMEN
Temozolomide (TMZ) resistance remains the major obstacle in the treatment of glioblastoma (GBM). Lactylation is a novel post-translational modification that is involved in various tumors. However, whether lactylation plays a role in GBM TMZ resistance remains unclear. Here it is found that histone H3K9 lactylation (H3K9la) confers TMZ resistance in GBM via LUC7L2-mediated intron 7 retention of MLH1. Mechanistically, lactylation is upregulated in recurrent GBM tissues and TMZ-resistant cells, and is mainly concentrated in histone H3K9. Combined multi-omics analysis, including CUT&Tag, SLAM-seq, and RNA-seq, reveals that H3K9 lactylation is significantly enriched in the LUC7L2 promoter and activates LUC7L2 transcription to promote its expression. LUC7L2 mediates intron 7 retention of MLH1 to reduce MLH1 expression, and thereby inhibit mismatch repair (MMR), ultimately leading to GBM TMZ resistance. Of note, it is identified that a clinical anti-epileptic drug, stiripentol, which can cross the blood-brain barrier and inhibit lactate dehydrogenase A/B (LDHA/B) activity, acts as a lactylation inhibitor and renders GBM cells more sensitive to TMZ in vitro and in vivo. These findings not only shed light on the mechanism of lactylation in GBM TMZ resistance but also provide a potential combined therapeutic strategy for clinical GBM treatment.
Asunto(s)
Resistencia a Antineoplásicos , Glioblastoma , Histonas , Intrones , Homólogo 1 de la Proteína MutL , Temozolomida , Animales , Humanos , Ratones , Antineoplásicos Alquilantes/farmacología , Antineoplásicos Alquilantes/uso terapéutico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral , Modelos Animales de Enfermedad , Resistencia a Antineoplásicos/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Glioblastoma/genética , Glioblastoma/tratamiento farmacológico , Glioblastoma/metabolismo , Histonas/metabolismo , Histonas/genética , Intrones/genética , Ratones Desnudos , Homólogo 1 de la Proteína MutL/genética , Homólogo 1 de la Proteína MutL/metabolismo , Temozolomida/farmacología , FemeninoRESUMEN
Time response is an important performance characteristic for gas-pressurized ionization chambers. To study the time response, it is especially crucial to measure the ion drift time in high pressure ionization chambers. In this paper, a new approach is proposed to study the ion drift time in high pressure ionization chambers. It is carried out with a short-pulsed X-ray source and a high-speed digitizer. The ion drift time in the chamber is then determined from the digitized data. By measuring the ion drift time of a 15 atm xenon testing chamber, the method has been proven to be effective in the time response studies of ionization chambers.
