RESUMEN
Considering the increasing risk of nuclear attacks worldwide, the development of develop potent and safe radioprotective agents for nuclear emergencies is urgently needed. γ-tocotrienol (GT3) and δ-tocotrienol (DT3) have demonstrated a potent radioprotective effect by inducing the production of granulocyte-colony stimulating factor (G-CSF) in vivo. However, their application is limited because of their low bioavailability. The utilization of ester prodrugs can be an effective strategy for modifying the pharmacokinetic properties of drug molecules. In this study, we initially confirmed that DT3 exhibited the most significant potential for inducing G-CSF effects among eight natural vitamin E homologs. Consequently, we designed and synthesized a series of DT3 ester and ether derivatives, leading to improved radioprotective effects. The metabolic study conducted in vitro and in vivo has identified DT3 succinate 5b as a prodrug of DT3 with an approximately seven-fold higher bioavailability compared to DT3 alone. And DT3 ether derivative 8a were relatively stable and approximately 4 times more bioavailable than DT3 prototype. Furthermore, 5b exhibited superior ability to mitigate radiation-induced pancytopenia, enhance the recovery of bone marrow hematopoietic stem and progenitor cells, and promote splenic extramedullary hematopoiesis in sublethal irradiated mice. Similarly, 8a shown potential radiation protection, but its radiation protection is less than DT3. Based on these findings, we identified 5b as a DT3 prodrug, and providing an attractive candidate for further drug development.
Asunto(s)
Sistema Hematopoyético , Profármacos , Protección Radiológica , Vitamina E/análogos & derivados , Animales , Ratones , Factor Estimulante de Colonias de Granulocitos/farmacología , Ésteres/farmacología , Éteres , Profármacos/farmacología , GranulocitosRESUMEN
To date only four recombinant growth factors, including Filgrastim (rhG-CSF), have been approved by FDA as radiomitigators to ameliorate hematopoietic acute radiation syndrome (H-ARS). These approved agents are not stable under room-temperature, needing to be stored at 2-8 °C, and would not be feasible in a mass casualty scenario where rapid and cost-effective intervention is crucial. Delta-tocotrienol (δ-T3H), the most potent G-CSF-inducing agent among vitamin E isoforms, exhibited efficiency and selectivity on G-CSF production in comparison with TLR and STING agonists in mice. Five-dose δ-T3H was utilized as the optimal therapeutic regimen due to long-term G-CSF production and the best peripheral blood (PB) recovery of irradiated mice. Comparable with rhG-CSF, sequential administration of δ-T3H post-irradiation improved hematologic recovery and accelerated the regeneration of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) in the bone marrow (BM) and spleen of 6.5Gy irradiated mice; and consistently enhanced repopulation of BM-HSCs. In 4.0Gy irradiated nonhuman primates, δ-T3H exhibited comparable efficacy as rhG-CSF to promote PB recovery and colony-formation of BM-HPCs. Altogether, we demonstrated that sequential administration of delta-tocotrienol ameliorates radiation-induced myelosuppression in mice and non-human primates through inducing G-CSF production, indicated δ-T3H as a promising radiomitigator for the management of H-ARS, particularly in a mass casualty scenario.
Asunto(s)
Médula Ósea , Células Madre Hematopoyéticas , Vitamina E , Animales , Ratones , Médula Ósea/patología , Médula Ósea/efectos de la radiación , Factor Estimulante de Colonias de Granulocitos/efectos de los fármacos , Factor Estimulante de Colonias de Granulocitos/metabolismo , Primates , Proteínas Recombinantes/farmacología , Vitamina E/análogos & derivados , Vitamina E/uso terapéuticoRESUMEN
TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.
Asunto(s)
Células Madre Neoplásicas , Proteína 1 de Unión a Repeticiones Teloméricas , Neoplasias de la Mama Triple Negativas , Humanos , Línea Celular Tumoral , Proliferación Celular , Regulación hacia Abajo , Resistencia a Antineoplásicos/genética , Regulación Neoplásica de la Expresión Génica , Células Madre Neoplásicas/metabolismo , Transducción de Señal , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/metabolismo , Proteína 1 de Unión a Repeticiones Teloméricas/genéticaRESUMEN
BACKGROUND: TAB182 is overexpressed in cancerous tissues and correlated with poor overall survival in lung cancer patients. Mechanistically, TAB182 participates in DNA damage repair and endows tumour cells with radio- and chemoresistance. However, its role in non-small cell lung cancer (NSCLC) remains unclear. METHODS AND RESULTS: Cells with stable TAB182 knockdown (KD) were generated using A549 NSCLC cells, and we demonstrated that depleting TAB182 inhibits cell EMT, proliferation, colony formation, migration and invasion. Analysis of the TCGA database showed a positive correlation between TAB182 and EGFR, a well-established NSCLC oncoprotein. Then, we verified that silencing TAB182 decreases EGFR expression at both the mRNA and protein levels. Moreover, both TAB182 and EGFR were reported to restore ionizing radiation (IR)-triggered DNA damage. We validated that IR elevates the protein level of EGFR and that silencing TAB182 can alleviate IR-induced EGFR upregulation. Furthermore, overexpressing EGFR abrogates the inhibitory effects of TAB182 KD on EMT, migration, and invasion in A549 cells. CONCLUSIONS: Our data demonstrated that EGFR expression is regulated by TAB182 and downregulation of TAB182 has a novel function to repress EMT, migration and invasion by decreasing EGFR, indicating TAB182 could regulate the malignant progression of NSCLC.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Células A549 , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Transición Epitelial-Mesenquimal/genética , Receptores ErbB/genética , Receptores ErbB/metabolismo , Regulación Neoplásica de la Expresión Génica/genética , Neoplasias Pulmonares/metabolismoRESUMEN
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is the core component of DNA-PK complex in the non-homologous end-joining (NHEJ) repair of DNA double-strand breaks, and its activity is strictly controlled by DNA-PKcs phosphorylation. The ubiquitin-like protein, NEDD8 is involved in regulation of DNA damage response, but it remains mysterious whether and how NEDD8-related neddylation affects DNA-PKcs and the NHEJ process. Here, we show that DNA-PKcs is poly-neddylated at its kinase domain. The neddylation E2-conjugating enzyme UBE2M and E3 ligase HUWE1 (HECT, UBA, and WWE domain containing E3 ubiquitin protein ligase 1) are responsible for the DNA-PKcs neddylation. Moreover, inhibition of HUWE1-dependent DNA-PKcs neddylation impairs DNA-PKcs autophosphorylation at Ser2056. Finally, depletion of HUWE1-dependent DNA-PKcs neddylation reduces the efficiency of NHEJ. These studies provide insights how neddylation modulates the activity of NHEJ core complex.
Asunto(s)
Daño del ADN , Proteína Quinasa Activada por ADN/metabolismo , Proteína NEDD8/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Línea Celular , Reparación del ADN por Unión de Extremidades , Proteína Quinasa Activada por ADN/química , Humanos , Fosforilación , Fosfoserina/metabolismo , Dominios ProteicosRESUMEN
Although the importance of the gut microbiota in the maintenance of human health has been well established, little is known about the impact of low-dose ionizing radiation ([LDR]; exposure to a dose of less than 0.5 Gy of low linear energy transfer radiation such as γ- or X-rays) on the composition and functional role of the gut microbiota. The aim of the present study was to investigate and compare the composition of the gut microbiota in mice exposed to LDR. Male BALB/c mice were exposed to low-dose Co60 radiation. Fecal samples taken prior to and after irradiation were used for high-throughput sequencing of 16S rRNA gene sequence amplicons. We observed substantial changes in the composition of the gut microbiota, including alpha diversity and beta diversity, in mice exposed to LDR compared with the nonradiated control group. Moreover, at the genus level, the abundance of Clostridium, Helicobacter, and Oscilibacter increased, and those of Bacteroides and Barnesiella decreased, in a time-dependent manner in the radiated groups compared with the nonradiated control group. The functional metabolic pathway analysis indicated that Bacteroides spp. and members of the other genera that were found are predicted to play roles in bacterial toxin production, DNA repair, and Type II diabetes. Furthermore, these alterations in the gut microbiota were accompanied by changes in the abundance of multiple metabolites, which were predicted to be involved in multiple signaling pathways, including glucagon, central carbon metabolism, and type II diabetes. The possibility of microbiota-mediated pathophysiology resulting from LDR may be an as yet unrecognized hazard that merits further experimental examination. This study provides a conceptual and analytical foundation for further research into the chronic effects of LDR on human health, and points to potential novel targets for intervention to prevent the adverse effects of radiation.