Silver Nanotriangles and Chemotherapeutics Synergistically Induce Apoptosis in Glioma Cells via a ROS-Dependent Mitochondrial Pathway

Design and development of locust bean gum-endowed/Phyllanthus reticulatus anthocyanin- functionalized biogenic gold nanosystem for enhanced antioxidative and anticancer chemotherapy

Herein, the design and fabrication of an anticancer nanoplatform (LBG/PRA-NG) based on locust bean gum-stabilized nanogold and functionalized with Phyllanthus reticulatus anthocyanins was described. LBG/PRA-NG was prepared in an eco-friendly, one-pot approach at room temperature, mediated by the anthocyanins and gum as bio-reductant and stabilizer, respectively. The nanostructure was elaborately characterized by FESEM, TEM, UV-visible, DLS, Zeta potential, FTIR, XRD, TGA/DTG, and XPS analysis. Its anticancer attributes were examined based on cytotoxicity on MCF-7 and MDA-MB-231 breast cancer cell lines, as well as the generation of intracellular reactive oxygen species. The results revealed the successful formation of a homogenous and highly stable nanocomposite (LBG/PRA-NG), with quasi-spherical shape, small size (14.73 nm), Zeta potential and PDI values of -58.30 mV and 0.237, respectively. The presence of a plasmonic peak at 525 nm was indicative of AuNPs. Compared to the galactomannan and anthocyanin, LBG/PRA-NG exhibited superior antioxidative properties with IC50 values of 35.44 μg/mL against DPPH and 24.55 μg/mL against ABTS+. Notably, LBG/PRA-NG also demonstrated enhanced anticancer properties relative to LBG and anthocyanins, with IC50 values of 16.17 μg/mL and 25.06 μg/mL against MCF-7 and MDA-MB-231 cells. Meanwhile, the normal cells (HEK-293 and L929) resisted the innocuous effects of LBG/PRA-NG. Furthermore, treatment of breast cancer cells with LBG/PRA-NG drastically elevated the intracellular ROS levels. This suggested that the anticancer activity of LBG/PRA-NG may be mediated via amplification of ROS/oxidative stress-induced apoptosis. Altogether, these findings indicate the remarkable potential of LBG/PRA-NC in the development of anticancer therapy.

In vivo C6 glioma models: an update and a guide toward a more effective preclinical evaluation of potential anti-glioblastoma drugs

Glioblastoma multiform (GBM) is the most common primary brain tumor with a poor prognosis and few therapeutic choices. In vivo, tumor models are useful for enhancing knowledge of underlying GBM pathology and developing more effective therapies/agents at the preclinical level, as they recapitulate human brain tumors. The C6 glioma cell line has been one of the most widely used cell lines in neuro-oncology research as they produce tumors that share the most similarities with human GBM regarding genetic, invasion, and expansion profiles and characteristics. This review provides an overview of the distinctive features and the different animal models produced by the C6 cell line. We also highlight specific applications of various C6 in vivo models according to the purpose of the study and offer some technical notes for more convenient/repeatable modeling. This work also includes novel findings discovered in our laboratory, which would further enhance the feasibility of the model in preclinical GBM investigations.

Natural and synthetic compounds for glioma treatment based on ROS-mediated strategy

Glioma is the most frequent and most malignant tumor of the central nervous system (CNS)，accounting for about 50% of all CNS tumor and approximately 80% of the malignant primary tumors in the CNS. Patients with glioma benefit from surgical resection, chemo- and radio-therapy. However these therapeutical strategies do not significantly improve the prognosis, nor increase survival rates owing to restricted drug contribution in the CNS and to the malignant characteristics of glioma. Reactive oxygen species (ROS) are important oxygen-containing molecules that regulate tumorigenesis and tumor progression. When ROS accumulates to cytotoxic levels, this can lead to anti-tumor effects. Multiple chemicals used as therapeutic strategies are based on this mechanism. They regulate intracellular ROS levels directly or indirectly, resulting in the inability of glioma cells to adapt to the damage induced by these substances. In the current review, we summarize the natural products, synthetic compounds and interdisciplinary techniques used for the treatment of glioma. Their possible molecular mechanisms are also presented. Some of them are also used as sensitizers: they modulate ROS levels to improve the outcomes of chemo- and radio-therapy. In addition, we summarize some new targets upstream or downstream of ROS to provide ideas for developing new anti-glioma therapies.

Adaptive regulations of Nrf2 alleviates silver nanoparticles-induced oxidative stress-related liver cells injury

Silver nanoparticles (AgNPs) are widely used in various fields such as industry, agriculture, and medical care because of their excellent broad-spectrum antibacterial activity. However, their extensive use has raised concerns about their health risks. Liver is one of the main target organs for the accumulation and action of AgNPs. Therefore, evaluating the toxic effects of AgNPs on liver cells and its mechanisms of action is crucial for the safe application of AgNPs. In the study, polyvinylpyrrolidone (PVP)-coated AgNPs were characterized. The human hepatoma cell line (HepG2) and the normal hepatic cell line (L02) were exposed to different concentrations of AgNPs (20-160 μg/mL) and pretreated with the addition of N-acetylcysteine (NAC) or by Nrf2 siRNA transfection. NAC was able to inhibit the concentration-dependent increase in the level of apoptosis induced by AgNPs in HepG2 cells and L02 cells. Interestingly, HepG2 cells were more sensitive to AgNPs than L02 cells, and this may be related to the different ROS generation and responses to AgNPs by cancer cells and normal cells. In addition, NAC also alleviated the imbalance of antioxidant system and cell cycle arrest, which may be related to AgNPs-induced DNA damage and autophagy. The knockdown of nuclear factor erythroid-derived factor 2-related factor (Nrf2) found that AgNPs-induced ROS and apoptosis levels were further upregulated, but the cell cycle arrest was alleviated. On the whole, Nrf2 exerts a protective role in AgNPs-induced hepatotoxicity. This study complements the hepatotoxicity mechanisms of AgNPs and provides data for a future exploration of AgNPs-related anti-hepatocellular carcinoma drugs.

Nanoformulation of Paclitaxel: Exploring the Cyclodextrin / PLGA Nano Delivery Carrier to Slow Down Paclitaxel Release, Enhance Accumulation in Vivo

Background: Improving the aggregation and penetration in tumor sites increases the anti-tumor efficacy of nanomedicine. In the current study, we designed cyclodextrin modified PLGA nanoparticles loaded with paclitaxel to elevate the accumulation and prolong circulation of chemotherapy drugs in vivo. Methods: The PLGA nanoparticles loaded with paclitaxel (PTX PLGA NPs) and cyclodextrin (CD) modified PLGA nanoparticles loaded with paclitaxel (PTX PLGA/CD NPs) were prepared using the emulsification solvent evaporation method. The nanoparticles were characterized by particle size, zeta potential, encapsulation efficiency, infrared spectroscopy analysis and X-Ray diffraction (XRD). Then, drug release of the nanoparticles was evaluated via reverse dialysis method in vitro. Finally, the in vivo distribution fate and pharmacokinetic characteristics of the nanoparticles were assessed in mice and rats. Results: The average particle size, zeta potential, and encapsulation efficiency of PTX PLGA NPs were (163.57±2.07) nm, - (20.53±2.79) mV and (60.44±6.80)%. The average particle size, zeta potential, and encapsulation efficiency of PTX PLGA/CD NPs were (148.57±1.66) nm, - (11.42±0.84) mV and (85.70±2.06)%. In vitro release studies showed that PTX PLGA/CD NPs were released more slowly compared to PTX PLGA NPs under normal blood pH conditions, while PTX PLGA/CD NPs were released more completely under tumor site pH conditions. The modified PLGA nanocarrier (PLGA/CD NPs) increased drug residence time and accumulation than the plain PLGA nanocarrier (PLGA NPs) in vivo distribution. In addition, the elimination half-life, area under the drug-time curve, and maximum blood concentration of the nanoparticle group were higher than those of Taxol^®, especially the PTX PLGA/CD NPs group, which was significantly different from Taxol^® and plain nanoparticle groups (p<0.001). Conclusions: The 2-HP-β-CD modified PLGA nanoparticles prolonged circulation time and accumulation of the chemotherapy drug paclitaxel in vivo.

Marine Compounds, Mitochondria, and Malignancy: A Therapeutic Nexus

The marine environment is important yet generally underexplored. It contains new sources of functional constituents that can affect various pathways in food processing, storage, and fortification. Bioactive secondary metabolites produced by marine microorganisms may have significant potential applications for humans. Various components isolated from disparate marine microorganisms, including fungi, microalgae, bacteria, and myxomycetes, showed considerable biological effects, such as anticancer, antioxidant, antiviral, antibacterial, and neuroprotective activities. Growing studies are revealing that potential anticancer effects of marine agents could be achieved through the modulation of several organelles. Mitochondria are known organelles that influence growth, differentiation, and death of cells via influencing the biosynthetic, bioenergetic, and various signaling pathways related to oxidative stress and cellular metabolism. Consequently, mitochondria play an essential role in tumorigenesis and cancer treatments by adapting to alterations in environmental and cellular conditions. The growing interest in marine-derived anticancer agents, combined with the development and progression of novel technology in the extraction and cultures of marine life, led to revelations of new compounds with meaningful pharmacological applications. This is the first critical review on marine-derived anticancer agents that have the potential for targeting mitochondrial function during tumorigenesis. This study aims to provide promising strategies in cancer prevention and treatment.

Potential targets and treatments affect oxidative stress in gliomas: An overview of molecular mechanisms

Oxidative stress refers to the imbalance between oxidation and antioxidant activity in the body. Oxygen is reduced by electrons as part of normal metabolism leading to the formation of various reactive oxygen species (ROS). ROS are the main cause of oxidative stress and can be assessed through direct detection. Oxidative stress is a double-edged phenomenon in that it has protective mechanisms that help to destroy bacteria and pathogens, however, increased ROS accumulation can lead to host cell apoptosis and damage. Glioma is one of the most common malignant tumors of the central nervous system and is characterized by changes in the redox state. Therapeutic regimens still encounter multiple obstacles and challenges. Glioma occurrence is related to increased free radical levels and decreased antioxidant defense responses. Oxidative stress is particularly important in the pathogenesis of gliomas, indicating that antioxidant therapy may be a means of treating tumors. This review evaluates oxidative stress and its effects on gliomas, describes the potential targets and therapeutic drugs in detail, and clarifies the effects of radiotherapy and chemotherapy on oxidative stress. These data may provide a reference for the development of precise therapeutic regimes of gliomas based on oxidative stress.

Identification and validation of RNA-binding protein-related gene signature revealed potential associations with immunosuppression and drug sensitivity in glioma

Background

Glioma is the most common central nervous system tumor in adults, and a considerable part of them are high‐degree ones with high malignancy and poor prognosis. At present, the classification and treatment of glioma are mainly based on its histological characteristics, so studies at the molecular level are needed.

Methods

RNA‐seq data from The Cancer Genome Atlas (TCGA) datasets (n = 703) and Chinese Glioma Genome Atlas (CGGA) were utilized to find out the differentially expressed RNA‐binding proteins (RBPs) between normal cerebral tissue and glioma. A prediction system for the prognosis of glioma patients based on 11 RBPs was established and validated using uni‐ and multi‐variate Cox regression analyses. STITCH and CMap databases were exploited to identify putative drugs and their targets. Single sample gene set enrichment analysis (ssGSEA) was used to calculate scores of specific immune‐related gene sets. IC50 of over 20,000 compounds in 60 cancer cell lines was collected from the CellMiner database to test the drug sensitivity prediction value of the RBP‐based signature.

Results

We established a reliable prediction system for the prognosis of glioma patients based on 11 RBPs including THOC3, LSM11, SARNP, PABPC1L2B, SMN1, BRCA1, ZC3H8, DZIP1L, HEXIM2, LARP4B, and ZC3H12B. These RBPs were primarily associated with ribosome and post‐transcriptional regulation. RBP‐based risk scores were closely related to immune cells and immune function. We also confirmed the potential of the signature to predict the drug sensitivity of currently approved or evaluated drugs.

Conclusions

Differentially expressed RBPs in glioma can be used as a basis for prognosis prediction, new drugs screening and drug sensitivity prediction. As RBP‐based glioma risk scores were associated with immunity, immunotherapy may become an important treatment for glioma in the future.

Oxidative Stress Activated by Sorafenib Alters the Temozolomide Sensitivity of Human Glioma Cells Through Autophagy and JAK2/STAT3-AIF Axis

The development of temozolomide (TMZ) resistance in glioma leads to poor patient prognosis. Sorafenib, a novel diaryl urea compound and multikinase inhibitor, has the ability to effectively cross the blood-brain barrier. However, the effect of sorafenib on glioma cells and the molecular mechanism underlying the ability of sorafenib to enhance the antitumor effects of TMZ remain elusive. Here, we found that sorafenib could enhance the cytotoxic effects of TMZ in glioma cells in vitro and in vivo. Mechanistically, the combination of sorafenib and TMZ induced mitochondrial depolarization and apoptosis inducing factor (AIF) translocation from mitochondria to nuclei, and this process was dependent on STAT3 inhibition. Moreover, the combination of sorafenib and TMZ inhibited JAK2/STAT3 phosphorylation and STAT3 translocation to mitochondria. Inhibition of STAT3 activation promoted the autophagy-associated apoptosis induced by the combination of sorafenib and TMZ. Furthermore, the combined sorafenib and TMZ treatment induced oxidative stress while reactive oxygen species (ROS) clearance reversed the treatment-induced inhibition of JAK2/STAT3. The results indicate that sorafenib enhanced the temozolomide sensitivity of human glioma cells by inducing oxidative stress-mediated autophagy and JAK2/STAT3-AIF axis.