Whole transcriptome and proteome analyses identify potential targets and mechanisms underlying tumor treating fields against glioblastoma.

Glioblastoma (GBM) is one of the most malignant types of brain cancer. Tumor treating fields (TTFields) is the up-to-date treatment for GBM. However, its molecular mechanism requires additional investigation. Herein, a novel TTFields system was developed (CL-301A) and its efficiency in suppressing GBM cell proliferation and inducing cell apoptosis was demonstrated. Through the whole proteomic and transcriptomic analyses, a multitude of differentially expressed proteins (1243), mRNAs (4191), miRtNAs (47), lncRNAs (4286), and circRNAs (13,903) were identified. Bioinformatic analysis indicated that TTFields mainly affected nuclear proteins and interrupt cell mitosis-related events. Moreover, the inhibition of autophagy could significantly enhance the anti-GBM activity of TTFields. And CDK2-AS1 might be a target of TTFields to mediate cell cycle arrest via regulating CDK2 mRNA stability. This study provided valuable resources for understanding the mechanism of TTFields, which might further assist the investigation of TTFields in GBM treatment.

A Nanoparticle-Conjugated Anti-TBK1 siRNA Induces Autophagy-Related Apoptosis and Enhances cGAS-STING Pathway in GBM Cells.

BACKGROUND: Gene therapy shows considerable clinical benefit in cancer therapy, in which single-stranded ribonucleic acid (siRNA) is a promising strategy in the treatment of glioblastoma (GBM). TANK-binding kinase 1 (TBK1) is critical in tumorigenesis and development, which lays a foundation for an ideal target for tumor therapy. However, the practical application of free siRNA is limited. It is urgent to develop novel strategies to deliver TBK1 siRNA to activate apoptosis and cGAS-STING pathway as a therapeutic strategy for GBM. METHODS: The expression and prognostic value of TBK1 were evaluated in the TCGA, CGGA, and GTEx databases. A novel gene delivery system was designed here via PEGylated reduced graphene oxide (rGO-PEG) to targeted delivery of anti-TBK1 siRNA efficiently. The efficacy of TBK1si/rGO-PEG was evaluated in GBM cells. The underlying pathways were explored by Western blot. RESULTS: TBK1 was highly expressed in glioma samples, and its high expression indicated poor prognoses in glioma patients. The rGO-PEG presented great efficiency in targeted delivery of TBK1si RNA into GBM cells with up to 97.1% transfection efficiency. TBK1si/rGO-PEG exhibited anti-GBM activities by inhibiting TBK1 and autophagy, as well as activating apoptosis and cGAS-STING pathway. CONCLUSION: The rGO-PEG could be an efficient system facilitating the delivery of specific siRNA. TBK1si/rGO-PEG could be a novel strategy for the treatment of GBM.

Evaluation of a tumor electric field treatment system in a rat model of glioma.

OBJECTIVE: Glioma is a devastating disease lacking effective treatment. Tumor electric field therapy is emerging as a novel non-invasive therapy. The current study evaluates the efficacy and safety of a self-designed tumor electric field therapy system (TEFTS ASCLU-300) in a rat orthotopic transplantation model of glioma. METHODS: A model of intracranial orthotopic transplantation was established in rats using glioma C6 cells. For electric field therapy, glioma-bearing rats were exposed to alternating electric fields generated by a self-developed TEFTS starting on either 1st (Group 2) or 3rd (Group 3) day after transplantation, while other conditions were maintained the same as non-treated rats (Group 1). Glioma size, body weight, and overall survival (OS) were compared between groups. Immunohistochemical staining was applied to access tumor cell death and microvessel density within the tumor. In addition, the systemic effects of TEFTS on blood cells, vital organs, and hepatorenal functions were evaluated. RESULTS: TEFTS treatment significantly elongated the OS of tumor-bearing rats compared with non-treated rats (non-treated vs treated: 24.77 ± 7.08 days vs 40.31 ± 19.11 days, P = .0031). Continuous TEFTS treatment starting on 1st or 3rd day significantly reduced glioma size at 2 and 3 weeks after tumor cell inoculation (Week 2: Group 1:289.95 ± 101.69 mm3 ; Group 2:70.45 ± 17.79 mm3 ; Group 3:73.88 ± 33.21 mm3 , P < .0001. Week 3: Group 1:544.096 ± 78.53 mm3 ; Group 2:187.58 ± 78.44 mm3 ; Group 3:167.14 ± 109.96 mm3 , P = .0005). Continuous treatment for more than 4 weeks inhibited tumor growth. The TEFTS treatment promoted tumor cell death, as demonstrated by increased number of Caspase 3+ cells within the tumor (non-treated vs treated: 38.06 ± 10.04 vs 68.57 ± 8.09 cells/field, P = .0007), but had minimal effect on microvessel density, as shown by CD31 expression (non-treated vs treated: 1.63 ± 0.09 vs 1.57 ± 0.13% of positively stained areas, P > .05). No remarkable differences were observed in hepatorenal function, blood cell counts, or other vital organs between non-treated and treated groups. CONCLUSION: The TEFTS developed by our research team was proved to be effective and safe to inhibit tumor growth and improve general outcomes in a rat model of brain glioma.

Tumor treating fields for high-grade gliomas.

High-grade gliomas (HGG) are the most common malignant intracranial tumors with poor prognosis. Current treatments have not yielded optimal remission rates; there are no standard treatments for recurrent and drug-resistant gliomas. Tumor treating fields, which was recently approved by the Food and Drug Administration (FDA), could significantly improve progression free survival and the overall survival of glioma patients. In this review, we elaborate on the mechanism of tumor treating fields in tumor cells and detail various preclinical and clinical studies on gliomas. Tumor treating fields could be a promising option for patients with malignant tumors for which there are no standard treatment plans. Moreover, we identify several potential problems for the practical application of tumor treating fields and predict future directions for further studies. Tumor treating fields may be a potential therapy with high efficacy, fewer adverse effects, and high cost-effectiveness.

Isolation of the sperm and egg cells in wild rice (Oryza officinalis) as a mechanism for crop improvement.

KEY MESSAGE: Sperm cells can be isolated from the mature pollen grains of medicinal wild rice (Oryza officinalis) using an osmotic shock method, and the viable egg cells can be isolated by enzymatic digestion and mechanical dissection steps. Favorable alleles for rice breeding have been identified in natural cultivars and wild rice by association analysis of known functional genes with target trait performance. Transferring these genes from wild rice into cultivated rice varieties is one of the important objectives for rice breeders. The isolation of the sperm and egg cells of wild and cultivated rice is a prerequisite for the in vitro hybridization of distantly related cultivated rice and wild rice lines. Here, we provide a technical approach for isolating the sperm and egg cells of wild rice (Oryza officinalis). In this method, sperm cells were isolated from the mature pollen grains of medicinal wild rice (O. officinalis) according to an osmotic shock method. Additionally, viable O. officinalis egg cells were isolated following enzymatic digestion and mechanical dissection steps. Specifically, ovules were digested in an enzymatic solution containing pectinase and cellulase for 30 min, after which the ovule was cut into two halves. Three egg apparatus cells were released by gently applying pressure to the micropylar end. Generally, six or seven egg cells could be isolated from 20 ovules in 60 min. The same method was used to isolate zygotes from flowers at 24 h after pollination. This technology solved the difficulty of isolating sperm and egg cells in O. officinalis and allowed the isolated sperm and egg cells to be combined by in vitro hybridization of distantly related wild and cultivated rice lines.

Phosphorus addition changes belowground biomass and C:N:P stoichiometry of two desert steppe plants under simulated N deposition.

Many studies have reported that increasing atmospheric nitrogen (N) deposition broadens N:phosphorus (P) in both soils and plant leaves and potentially intensifies P limitation for plants. However, few studies have tested whether P addition alleviates N-induced P limitation for plant belowground growth. It is also less known how changed N:P in soils and leaves affect plant belowground stoichiometry, which is significant for maintaining key belowground ecological processes. We conducted a multi-level N:P supply experiment (varied P levels combined with constant N amount) for Glycyrrhiza uralensis (a N fixing species) and Pennisetum centrasiaticum (a grass) from a desert steppe in Northwest China during 2011-2013. Results showed that increasing P addition increased the belowground biomass and P concentrations of both species, resulting in the decreases in belowground carbon (C):P and N:P. These results indicate that P inputs alleviated N-induced P limitation and hence stimulated belowground growth. Belowground C:N:P stoichiometry of both species, especially P. centrasiaticum, tightly linked to soil and green leaf C:N:P stoichiometry. Thus, the decoupling of C:N:P ratios in both soils and leaves under a changing climate could directly alter plant belowground stoichiometry, which will in turn have important feedbacks to primary productivity and C sequestration.