Edited by Varda RotterKeywords: cH2AX CHK2 DNA-PKcs DNA damage Mitosis a b s t r a c t Phosphorylated H2AX is considered to be a biomarker for DNA double-strand breaks (DSB), but recent evidence suggests that cH2AX does not always indicate the presence of DSB. Here we demonstrate the bimodal dynamic of H2AX phosphorylation induced by ionizing radiation, with the second peak appearing when G2/M arrest is induced. An increased level of cH2AX occurred in mitotic cells, and this increase was attenuated by DNA-PKcs inactivation or Chk2 depletion, but not by ATM inhibition. The phosphorylation-mimic CHK2-T68D abrogated the attenuation of mitotic cH2AX induced by DNA-PKcs inactivation. Thus, the DNA-PKcs/CHK2 pathway mediates the mitotic phosphorylation of H2AX in the absence of DNA damage.
Pancreatic cancer, one of the most lethal human malignancies with dismal prognosis, is refractory to existing radio-chemotherapeutic treatment modalities. There is a critical unmet need to develop effective approaches, especially for targeted pancreatic cancer drug delivery. Targeted and drug-loaded nanoparticles (NPs) combined with ultrasound-mediated microbubble destruction (UMMD) have been shown to significantly increase the cellular uptake in vitro and drug retention in vivo, suggesting a promising strategy for cancer therapy. In this study, we synthesized pancreatic cancer-targeting organic NPs that were modified with anti CA19-9 antibody and encapsulated paclitaxol (PTX). The three-block copolymer methoxy polyethylene glycol-polylacticco-glycolic acid-polylysine (mPEG-PLGA-PLL) constituted the skeleton of the NPs. We speculated that the PTX-NPs-anti CA19-9 would circulate long-term in vivo, "actively target" pancreatic cancer cells, and sustainably release the loaded PTX while UMMD would "passively target" the irradiated tumor and effectively increase the permeability of cell membrane and capillary gaps. Our results demonstrated that the combination of PTX-NPs-anti CA19-9 with UMMD achieved a low IC50, significant cell cycle arrest, and cell apoptosis in vitro. In mouse pancreatic tumor xenografts, the combined application of PTX-NP-anti CA19-9 NPs with UMMD attained the highest tumor inhibition rate, promoted the pharmacokinetic profile by increasing AUC, t1/2, and mean residence time (MRT), and decreased clearance. Consequently, the survival of the tumor-bearing nude mice was prolonged without obvious toxicity. The dynamic change in cellular uptake, targeted real-time imaging, and the concentration of PTX in the plasma and tumor were all closely associated with the treatment efficacy both in vitro and in vivo. Our study suggests that PTX-NP-anti CA19-9 NPs combined with UMMD is a promising strategy for the treatment of pancreatic cancer.
The efficacy of radiation therapy (RT) is often limited by the poor response of hypoxia inside most solid tumors. The development of a theranostic nanoplatform for precision‐imaging‐guided sensitized RT for tumor hypoxia is still challenging. Herein, the creation of hypoxia‐targeted dendrimer‐entrapped gold nanoparticles complexed with gadolinium(III) (Gd‐Au DENPs‐Nit) for dual‐mode CT/MR imaging and sensitized RT of hypoxic tumors is reported. In this work, generation 5 poly(amidoamine) dendrimers are partially conjugated with Gd(III) chelator, entrapped with Au nanoparticles, and conjugated with hypoxia‐targeting agent nitroimidazole via a polyethylene glycol linker, and ending with chelation of Gd(III) and conversion of their leftover amine termini to acetamides. The designed dendrimer‐based nanohybrids with 3.2 nm Au cores exhibit an excellent X‐ray attenuation effect, acceptable r1 relaxivity (1.32 mM−1 s−1), and enhanced cellular uptake in hypoxic cancer cells, affording efficient dual‐mode CT/MR imaging of tumor hypoxia. Under X‐ray irradiation, the Gd‐Au DENPs‐Nit nanohybrids can produce reactive oxygen species, promote DNA damage, and prevent DNA repair, facilitating sensitized RT of hypoxic cancer cells in vitro and tumor hypoxia in vivo. The developed hypoxia‐targeted dendrimer‐based nanohybrids may be employed as both contrast agents and nanosensitizers for precision tumor hypoxia imaging and sensitized tumor RT.
Background Apatinib is a tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor-2 (VEGFR2), and has shown encouraging therapeutic effects in various malignant tumors. As yet, however, the role of apatinib in ovarian cancer has remained unknown. Here, we sought to elucidate the role of apatinib in the in vitro and in vivo viability and proliferation of ovarian cancer cells, as well as in glucose metabolism in these cells. Methods The effects of apatinib on ovarian cancer cell viability and proliferation were assessed using Cell Counting Kit-8 (CCK-8) and colony formation assays, respectively. The expression of VEGFR2/AKT1/SOX5/GLUT4 pathway proteins was assessed using Western blotting, and glucose uptake and lactate production assays were used to detect glycolysis in ovarian cancer cells. SOX5 was exogenously over-expressed and silenced in ovarian cancer cells using expression vector and shRNA-based methods, respectively. RNA expression analyses were performed using RNA-seq and gene-chip-based methods. GLUT4 promoter activity was assessed using a dual-luciferase reporter assay. The expression of p-VEGFR2 (Tyr1175), p-AKT1 (Ser473), p-GSK3β (Ser9), SOX5 and GLUT4 in xenograft tissues was assessed using immunohistochemistry (IHC). Results We found that apatinib inhibited the in vitro and in vivo viability and proliferation in Hey and OVCA433 ovarian cancer cells in a dose-dependent and time-dependent manner. We also found that apatinib effectively suppressed glucose uptake and lactate production by blocking the expression of GLUT4 in these cells. In addition, we found that SOX5 predominantly rescued the inhibitory effect of apatinib on GLUT4 expression by activating its promoter. Finally, we found that apatinib regulated the expression of SOX5 by suppressing the VEGFR2/AKT1/GSK3β signaling pathway. Conclusions From our results, we conclude that apatinib suppresses the in vitro and in vivo viability and proliferation of ovarian cancer cells, as well as glycolysis by inhibiting the VEGFR2/AKT1/GSK3β/SOX5/GLUT4 signaling pathway. Apatinib may serve as a promising drug for the treatment of ovarian cancer.
The abscopal effect could be an underlying factor in evaluating prognosis of radiotherapy. This study established an in vitro system to examine whether tumor-generated bystander signals could be transmitted by macrophages to further trigger secondary cellular responses after different irradiations, where human lung cancer NCI-H446 cells were irradiated with either γ-rays or carbon ions and co-cultured with human macrophage U937 cells, then these U937 cells were used as a bystander signal transmitter and co-cultured with human bronchial epithelial cells BEAS-2B. Results showed that U937 cells were only activated by γ-irradiated NCI-H446 cells so that the secondary injuries in BEAS-2B cells under carbon ion irradiation were weaker than γ-rays. Both TNF-α and IL-1α were involved in γ-irradiation induced secondary bystander effect but only TNF-α contributed to the carbon ion induced response. Further assay disclosed that IL-1α but not TNF-α was largely responsible for the activation of macrophages and the formation of micronucleus in BEAS-2B cells. These data suggest that macrophages could transfer secondary bystander signals and play a key role in the secondary bystander effect of photon irradiation while carbon ion irradiation has conspicuous advantage due to its reduced secondary injury.
Multifunctional nanomaterials that have integrated diagnostic and therapeutic functions and low toxicity, and can enhance treatment efficacy through combination therapy have drawn tremendous amounts of attention. Herein, a newly developed multifunctional theranostic agent is reported, which is PEGylated W-doped TiO
2
(WTO) nanoparticles (NPs) synthesized via a facile organic route, and the results demonstrated strong absorbance of these WTO NPs in the second near-infrared (NIR-II) window due to successful doping with W. These PEGylated WTO NPs can absorb both NIR-II laser and ionizing radiation, rendering them well suited for dual-modal computed tomography/NIR-II photoacoustic imaging and synergistic NIR-II photothermal/radiotherapy of tumors. In addition, the long-term in vivo studies indicated that these PEGylated WTO NPs had no obvious toxicity on mice in vivo, and they can be cleared after a 30-day period. In summary, this multifunctional theranostic agent can absorb both NIR-II laser and ionizing radiation with negligible toxicity and rapid clearance, therefore it has great promise for applications in imaging and therapeutics in biomedicine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.