Enhanced ROS Generation Research Articles

A novel therapeutic strategy of multimodal nanoconjugates for state-of-the-art brain tumor phototherapy

BackgroundThe outcome of phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) for glioblastoma multiforme (GBM), is disappointing due to insufficient photoconversion efficiency and low targeting rate. The development of phototherapeutic agents that target GBM and generate high heat and potent ROS is important to overcome the weak anti-tumor effect.ResultsIn this study, nanoconjugates composed of gold nanoparticles (AuNPs) and photosensitizers (PSs) were prepared by disulfide conjugation between Chlorin e6 (Ce6) and glutathione coated-AuNP. The maximum heat dissipation of the nanoconjugate was 64.5 ± 4.5 °C. Moreover, the proximate conjugation of Ce6 on the AuNP surface resulted in plasmonic crossover between Ce6 and AuNP. This improves the intrinsic ROS generating capability of Ce6 by 1.6-fold compared to that of unmodified-Ce6. This process is called generation of metal-enhanced reactive oxygen species (MERos). PEGylated-lactoferrin (Lf-PEG) was incorporated onto the AuNP surface for both oral absorption and GBM targeting of the nanoconjugate (denoted as Ce6-AuNP-Lf). In this study, we explored the mechanism by which Ce6-AuNP-Lf interacts with LfR at the intestinal and blood brain barrier (BBB) and penetrates these barriers with high efficiency. In the orthotopic GBM mice model, the oral bioavailability and GBM targeting amount of Ce6-AuNP-Lf significantly improved to 7.3 ± 1.2% and 11.8 ± 2.1 μg/kg, respectively. The order of laser irradiation, such as applying PDT first and then PTT, was significant for the treatment outcome due to the plasmonic advantages provided by AuNPs to enhance ROS generation capability. As a result, GBM-phototherapy after oral administration of Ce6-AuNP-Lf exhibited an outstanding anti-tumor effect due to GBM targeting and enhanced photoconversion efficiency.ConclusionsThe designed nanoconjugates greatly improved ROS generation by plasmonic crossover between AuNPs and Ce6, enabling sufficient PDT for GBM as well as PTT. In addition, efficient GBM targeting through oral administration was possible by conjugating Lf to the nanoconjugate. These results suggest that Ce6-AuNP-Lf is a potent GBM phototherapeutic nanoconjugate that can be orally administered.Graphical

Heterogeneity of glutamine metabolism in acquired-EGFR-TKI-resistant lung cancer

AimsThe purpose of this study was to evaluate the heterogeneities of glutamine metabolism in EGFR-TKI-resistant lung cancer cells and its potential as a therapeutic target. Main methodsCell proliferation and cell cycle assays was performed by IncuCyte real-time analysis and flow cytometry, respectively. Tumor growth was assessed in xenografts implanted with HCC827 GR. An isotopologue analysis was conducted by LC-MS/MS using 13C-(U)-glutamine labeling to determine the amounts of metabolites. Cellular ATP and mitochondrial oxidative phosphorylation were determined by XFp analysis. Key findingsWe found that the cell growth of the two acquired EGFR-TKI-resistant lung cancer cells lines (HCC827 GR and H292 ER) depends on glutamine. In HCC827 GR, glutamine deficiency caused reduced GSH synthesis and, subsequently, enhanced ROS generation relative to their parental cells, HCC827. On the other hand, in H292 ER, glutamine mainly acted as a carbon source for TCA-cycle intermediates, and its depletion led to reduced mitochondrial ATP production. CB-839, a specific GLS inhibitor, inhibited the latter's conversion of glutamine to glutamate and exerted enhanced anti-proliferating effects on the two acquired EGFR-TKI-resistant lung cancer cell lines versus their parental cell lines. Moreover, oral administration of CB-839 significantly suppressed HCC827 GR tumor growth in the xenograft model. SignificanceThese findings suggest that glutamine dependency in acquired EGFR-TKI-resistant lung cancer is heterogeneous and that inhibition of glutamine metabolism by CB-839 may serve as a therapeutic tool for acquired EGFR-TKI-resistant lung cancer.

Epithelial Aryl Hydrocarbon Receptor Protects From Mucus Production by Inhibiting ROS-Triggered NLRP3 Inflammasome in Asthma.

BackgroundDespite long-standing recognition in the significance of mucus overproduction in asthma, its etiology remains poorly understood. Muc5ac is a secretory mucin that has been associated with reduced pulmonary function and asthma exacerbations.ObjectivesWe sought to investigate the immunological pathway that controls Muc5ac expression and allergic airway inflammation in asthma.MethodsCockroach allergen-induced Muc5ac expression and aryl hydrocarbon receptor (AhR) signaling activation was examined in the human bronchial epithelial cells (HBECs) and mouse model of asthma. AhR regulation of Muc5ac expression, mitochondrial ROS (Mito-ROS) generation, and NLRP3 inflammasome was determined by AhR knockdown, the antagonist CH223191, and AhR-/- mice. The role of NLRP3 inflammasome in Muc5ac expression and airway inflammation was also investigated.ResultsCockroach allergen induced Muc5ac overexpression in HBECs and airways of asthma mouse model. Increased expression of AhR and its downstream genes CYP1A1 and CYP1B1 was also observed. Mice with AhR deletion showed increased allergic airway inflammation and MUC5AC expression. Moreover, cockroach allergen induced epithelial NLRP3 inflammasome activation (e.g., NLRP3, Caspase-1, and IL-1β), which was enhanced by AhR knockdown or the antagonist CH223191. Furthermore, AhR deletion in HBECs led to enhanced ROS generation, particularly Mito-ROS, and inhibition of ROS or Mito-ROS subsequently suppressed the inflammasome activation. Importantly, inhibition of the inflammasome with MCC950, a NLRP3-specifc inhibitor, attenuated allergic airway inflammation and Muc5ac expression. IL-1β generated by the activated inflammasomes mediated cockroach allergen-induced Muc5ac expression in HBECs.ConclusionsThese results reveal a previously unidentified functional axis of AhR-ROS-NLRP3 inflammasome in regulating Muc5ac expression and airway inflammation.

Multiple pathways of alveolar macrophage death contribute to pulmonary inflammation induced by silica nanoparticles

In our previous study, 20 nm-sized amorphous silica nanoparticles (20-SiNPs), but not 50 nm-sized amorphous silica nanoparticles (50-SiNPs), induced pulmonary inflammatory response in rats exposed repeatedly for 14 days (12.5, 25, and 50 μg/time, total six times). In this study, we tried to clarify the causes of different responses induced by both SiNPs using mice (12.5, 25, and 50 μg/lung) and mouse alveolar macrophage cells. When exposed to alveolar macrophage cells for 24 h, both SiNPs decreased cell viability and enhanced ROS generation compared to controls. The 20- and 50-SiNPs also formed giant and autophagosome-like vacuoles in the cytoplasm, respectively. Structural damage of organelles was more pronounced in 20-SiNPs-treated cells than in 50-SiNPs-treated cells, and an increased mitochondrial membrane potential and mitochondrial calcium accumulation were observed only in the 20-SiNPs-treated cells. Additionally, a single intratracheal instillation of both sizes of SiNPs to mice clearly elevated the relative proportion of neutrophils and inhibited differentiation of macrophages and expression of an adhesion molecule. Meanwhile, interestingly, the total number of pulmonary cells and the levels of pro-inflammatory mediators more notably increased in the lungs of mice exposed to 20-SiNPs compared to 50-SiNPs. Given that accumulation of giant vacuoles and dilation of the ER and mitochondria are key indicators of paraptosis, we suggest that 20-SiNPs-induced pulmonary inflammation may be associated with paraptosis of alveolar macrophages.

CircSNX6 (hsa_circ_0031608) enhances drug resistance of non-small cell lung cancer (NSCLC) via miR-137

circRNAs have been suggested to modulate NSCLC tumorigenesis and drug resistance. Whether circSNX6 affects NSCLC remains unclear. In this study, we aim to investigate the role of circSNX6 in drug resistance of NSCLC exposed to cisplatin. RT-qPCR method was used to investigate expression levels of circSNX6, miR-137 and CXCL12. MTT, cell colony formation and TUNEL assays were utilized to assess cell viability, proliferation, apoptosis, respectively. Xenograft assay was conducted to examinein vivotumor growth. circSNX6 overexpression caused enhanced cell viability and proliferation of H1299 and Calu-1, while it inhibited apoptosis under cisplatin treatment. miR-137 inhibitor greatly rescued cell viability, proliferation and apoptosis of circSNX6 knockdown H1299 cells. miR-137 mimic increased ROS generation, as well as reduced GSH and SOD levels, whereas miR-137 inhibitor exerted opposing effect. circSNX6 knockdown also enhanced ROS generation, as well as decreased GSH and SOD levels. CXCL12 partially restored miR-137 mimic-modulated cell viability, proliferation and apoptosis. Herein, our group proposes circSNX6 as key regulator for drug resistance of NSCLC. The findings provide solid groundings for understanding of NSCLC pathogenesis and development of therapeutics.

Tridentate 3-Substituted Naphthoquinone Ruthenium Arene Complexes: Synthesis, Characterization, Aqueous Behavior, and Theoretical and Biological Studies.

A series of nine RuII arene complexes bearing tridentate naphthoquinone-based N,O,O-ligands was synthesized and characterized. Aqueous stability and their hydrolysis mechanism were investigated via UV/vis photometry, HPLC-MS, and density functional theory calculations. Substituents with a positive inductive effect improved their stability at physiological pH (7.4) intensely, whereas substituents such as halogens accelerated hydrolysis and formation of dimeric pyrazolate and hydroxido bridged dimers. The observed cytotoxic profile is unusual, as complexes exhibited much higher cytotoxicity in SW480 colon cancer cells than in the broadly chemo- (incl. platinum-) sensitive CH1/PA-1 teratocarcinoma cells. This activity pattern as well as reduced or slightly enhanced ROS generation and the lack of DNA interactions indicate a mode of action different from established or previously investigated classes of metallodrugs.

Design, synthesis and broad spectrum antibreast cancer activity of diarylindoles via induction of apoptosis in aggressive breast cancer cells

Breast cancer is the second leading cause of cancer deaths in women with significant morbidity and mortality. Present study describes design, synthesis and detailed pharmacology of indole derivatives exhibiting remarkable broad spectrum antiproliferative activity against breast cancer cells. Detailed mechanistic evaluations confirmed induction of G0/G1 arrest, apoptosis induction, loss of mitochondrial integrity, enhanced ROS generation, autophagy, estrogen receptor β-transactivation and increased tubulin polymerization. In in-vivo efficacy studies in rodent model, these indole derivatives induced significant regression in mice mammary tumour on 21 days daily oral dose. Moreover, compounds 19 and 23 were safe in Swiss albino mice in safety studies. These diarylindoles may further be optimized for better efficacy.

Ligand-targeted Theranostic Liposomes combining methylene blue attached upconversion nanoparticles for NIR activated bioimaging and photodynamic therapy against HER-2 positive breast cancer

Methylene Blue (MB) based Photodynamic therapy (PDT) has gained much interest recently due to its FDA approval for treating various diseased conditions in human. Herein, we report for the first time the systematic evaluation of NIR-controlled PDT efficiency of free MB and MB attached on NaYF4:Yb, Er nanoparticles (UCNPs) i.e., MB@UCNPs encapsulated within Liposomes (LPs). The UCNPs act as an upconverting energy source for the photosensitizers dye MB for enhanced ROS generation and utilizing the remnant energy for selective tracking or bioimaging. The specificity of our nano LPs system was achieved by conjugating our newly discovered anti-HER2 peptides by phage display technique and demonstrated its specificity by confocal imaging of HER-2 overexpressing in vitro model. A significant decline in the cell viability by 83% and 64% was achieved by the LPs containing MB@UCNPs and free MB with UCNPs, respectively after 975 nm NIR laser exposure (0.60 W/cm−2) for 5 min continuous exposure. Also, the flowcytometry assay confirmed that enhanced ROS generation capability of LPs with MB@UCNPs was higher than the free MB with UCNPs, which states the relevance of the minimal distance between MB and UCNPs for higher anti-cancer efficiency.

Securinine Induces Differentiation of Human Promyelocytic Leukemic HL-60 Cells through JNK-Mediated Signaling Pathway

Acute myeloid leukemia is characterized by abnormal differentiation of hematopoietic stem cells, leading to the accumulation of immature myeloid cells. Differentiation therapy has been a successful treatment option for acute promyelocytic leukemia but suffers from adverse effects. Therefore, search for novel differentiation-inducing agents with minimal side effects is desirable. Securinine, a naturally-occurring alkaloid, induces differentiation in various leukemic cells and apoptosis in other types of cancers. However, the underlying molecular mechanism(s) remain elusive. Our study aimed to elucidate the possible molecular mechanism(s) and signaling events involved in securinine-induced differentiation of HL-60 cells. Securinine inhibited proliferation in a time- and dose-dependent manner and triggered differentiation. A higher CD14+ population indicated maturation toward monocytic lineage. Securinine caused cell cycle arrest at the G0/G1 phase and enhanced ROS generation. Quantitative gene expression analysis showed significant down-regulation of C/EBP-α, C/EBP-ε, GAΤΑ, and c-myc and up-regulation of the PU.1 gene. The expression of distinct protein kinases Lyn, Chk-2, Yes, FAK, c-Jun, and JNK were enhanced. Use of specific inhibitors of crucial intracellular signaling proteins indicated that JNK and ERK blockade resulted in a significant decline in differentiation. These data thus confirm that securinine induces differentiation through the activation of the JNK-ERK signaling pathway in HL-60 cells.

Bioallethrin enhances generation of ROS, damages DNA, impairs the redox system and causes mitochondrial dysfunction in human lymphocytes

Bioallethrin is a synthetic pesticide that is widely used to control insect pests. The wide use of bioallethrin has resulted in inevitable human exposure. In this study we report the effect of different concentrations of bioallethrin (10 to 200 µM, 2 h at 37 °C) on human lymphocytes under in vitro conditions. Bioallethrin treatment resulted in loss of cell viability (> 30% at 200 µM bioallethrin). Oxidative stress markers like lipid peroxidation and protein oxidation were significantly increased accompanied by lower ratio of reduced to oxidized glutathione. Enhanced ROS generation was observed through fluorescence spectroscopy and microscopy. Bioallethrin-induced oxidative stress also compromised the antioxidant defence as it reduced antioxidant capacity of cells and inhibited major antioxidant enzymes. Biomolecular modifications and systemic toxicity by bioallethrin resulted in plasma membrane damage with mitochondrial depolarization. Comet assay showed nuclear DNA fragmentation and strand scission with significant increase in tail length and olive tail moment. Apoptosis and necrosis of cells was confirmed through acridine orange/ethidium bromide dual staining and visualization under fluorescence microscope. Thus, bioallethrin causes oxidative damage and compromises the antioxidant system leading to DNA damage, cellular and organelle toxicity, resulting in apoptosis and necrosis of human lymphocytes.

Phototherapy and anti-GITR antibody-based therapy synergistically reinvigorate immunogenic cell death and reject established cancers

Phototherapy and immunogenic cell death (ICD) are powerful strategies to fight cancer. However, their therapeutic outcomes are diminished by immunosuppressive and hypoxia microenvironment. Herein, a photo-based, immunomodulating and hypoxia-alleviated nanosystem, PDA-ICG@CAT-DTA-1, is proposed to achieve the synergism between phototherapy and immunotherapy. Catalase (CAT) and anti-GITR antibody (DTA-1) are loaded to photothermal agent and photosensitizer composed PDA-ICG nanoparticles. The PDA-ICG@CAT-DTA-1 exhibits intrinsic local hyperthermia and enhanced ROS generation in tumor, and abrogates tumor immune suppression. It results in reduction of intratumoral FOXP3+ regulatory T cells (4.3-fold) and increase of CD4+ effector T cells (1.5-fold) compare with the control, and promotes damage associated molecular patterns generation to reinvigorate ICD effect. The potent antitumor of PDA-ICG@CAT-DTA-1 is proved in 4T1 bilateral tumor-bearing mice, with inhibition ratio of 95.1% for primary cancers and 68.7% for abscopal cancers. Our findings highlight great promise of the constructed versatility nanosystem to fix bottlenecks for cancer therapy.

Tumor-specific carrier-free nanodrugs with GSH depletion and enhanced ROS generation for endogenous synergistic anti-tumor by a chemotherapy-photodynamic therapy

Combining chemotherapy and photodynamic therapy (PDT) with a nanoscale drug delivery system (NDDS) has been widely developed to improve the therapeutic efficacy and biological safety of current treatments. However, the excess glutathione (GSH) in tumor cells impedes the ROS generation from photosensitizers, leading to reduction of PDT efficacy. Moreover, most NDDS also have been restricted due to the complexity of the multi-component, batch to batch differences, carrier-related toxicity and poor drug loading issues. To overcome these problems, a novel carrier-free nanodrug (GA-Ce6-FA NPs) was developed to achieve chemotherapy combined PDT synergistic treatment by a simple and green self-assembly approach, and the NPs was made up of gambogic acid (GA), chlorin e6 (Ce6) and folic acid (FA), in which GA was not only used as a chemotherapy drug but also designed to deplete GSH in tumor for enhancing PDT efficacy. The GA-Ce6-FA NPs exhibited a diameter of ~135 nm, which favored the NPs accumulation in tumor by a potential EPR effect. Meanwhile, the GA-Ce6-FA NPs had a pH-triggered drug release profile under a weak acidic condition, which could fast release drugs at the tumor region. It significantly enhanced the intracellular Ce6 uptake due to FA active targeting. Moreover, GA-Ce6-FA NPs could induce efficient apoptosis of MCF-7 cells, and offer a significant anti-tumor function by chemotherapy-PDT, which indicated depleting GSH by chemotherapeutics was an effective way to improve the efficacy of PDT. Thus, by the carrier-free NPs, a strategy of using multi-functional anticancer drugs as endogenous synergistic agents to PDT is useful to enhance anti-tumor efficacy.

Elevated ROS depress mitochondrial oxygen utilization efficiency in cardiomyocytes during acute hypoxia.

Mitochondria are important sites for the production of ATP and the generation of ROS in cells. However, whether acute hypoxia increases ROS generation in cells or affects ATP production remains unclear, and therefore, monitoring the changes in ATP and ROS in living cells in real time is important. In this study, cardiomyocytes were transfected with RoGFP for ROS detection and MitGO-Ateam2 for ATP detection, whereby ROS and ATP production in cardiomyocytes were respectively monitored in real time. Furthermore, the oxygen consumption rate (OCR) of cardiomyocytes was measured. Similar results were produced for adult and neonatal rat cardiomyocytes. Hypoxia (1% O2) reduced the basal OCR, ATP-linked OCR, and maximal OCR in cardiomyocytes compared with these OCR levels in the cardiomyocytes in the normoxic group (21% O2). However, ATP-linked OCR, normalized to maximal OCR, was increased during hypoxia, indicating that the electron leakage of complex III exacerbated the increase of ATP-linked oxygen consumption during hypoxia and vice versa. Combined with the result that cardiomyocytes expressing MitGO-Ateam2 showed a significant decrease in ATP production during hypoxia compared with that of normoxic group, acute hypoxia might depress the mitochondrial oxygen utilization efficiency of the cardiomyocytes. Moreover, cardiomyocytes expressing Cyto-RoGFP or IMS-RoGFP showed an increase in ROS generation in the cytosol and the mitochondrial intermembrane space (IMS) during hypoxia. All of these results indicate that acute hypoxia generated more ROS in complex III and increased mitochondrial oxygen consumption, leading to less ATP production. In conclusion, acute hypoxia depresses the mitochondrial oxygen utilization efficiency by decreasing ATP production and increasing oxygen consumption as a result of the enhanced ROS generation at mitochondrial complex III.

Antitumorigenic Effect of Hsp90 Inhibitor SNX-2112 on Tongue Squamous Cell Carcinoma is Enhanced by Low-Intensity Ultrasound.

PurposeThe novel Hsp90 inhibitor SNX-2112 showed broad antitumor activity. However, it was still necessary to optimize the therapeutic dosage of SNX-2112 applied on tumors to obtain effective therapy with minimal dose to reduce toxicity. We investigated the role of low-intensity US in promoting antitumorigenic effect of low doses of SNX-2112 on tongue squamous cell carcinoma.MethodsCell viability was measured using CCK-8 assay or staining with Calcein AM/PI. Relative cumulative levels of SNX-2112 in cells were detected using high-performance liquid chromatography. The production of ROS was analyzed using fluorescence microscope and flow cytometer. Cellular apoptosis was detected using flow cytometer. The expression levels of proteins of the ERS-associated apoptosis signaling pathway were detected using Western blotting analysis. The efficacy and biosafety of SNX-2112 were also investigated in a mouse xenograft model.ResultsLow-intensity US combined with SNX-2112 exhibited significant antitumor effect, increased the absorption of SNX-2112 by cells even with a low dose, enhanced ROS generation and apoptosis. The combination regimen also inhibited the protein expression of Hsp90 and triggered apoptosis through endoplasmic reticulum stress (ERS) by enhancing PERK, CHOP and Bax protein levels, while downregulating the level of Bcl-2. Additionally, N-acetyl-L-cysteine (NAC), ROS scavenger, was able to reverse these results. Low-intensity US combined with SNX-2112 significantly inhibited tumor growth, prolonged survival of mice, decreased proliferation and promoted apoptosis with no visible damage or abnormalities in major organs in the mouse xenograft model with tongue squamous cell carcinoma.ConclusionThe antitumor effects of SNX-2112 were enhanced by low-intensity US. The most probable mechanism was that US sonoporation induced more SNX-2112 delivery to the cells and enhanced ROS production, triggering the ERS-associated apoptosis signaling pathway. Therefore, low-intensity US may increase the efficiency of conventional chemotherapy and reduce the dosage of SNX-2112 required and its side effects.

Electrostatically bound lanreotide peptide - gold nanoparticle conjugates for enhanced uptake in SSTR2-positive cancer cells.

Lanreotide peptide (LP) has high affinity to somatostatin receptors like SSTR2 and is commonly used in the treatment of neuro-endocrine tumors. The main objective of this study is to target gold nanoparticles (AuNPs) towards SSTR2-positive cancer cells using lanreotide peptide (LP) as the targeting agent for enhanced tumor uptake and antitumor activity. pH mediated changes in the surface potential of LP and AuNP is used to prepare electrostatically bound AuNP-LP complexes. AuNP-LP complex formation was demonstrated by UV-Visible spectroscopy, surface potential, dynamic light scattering (DLS), small angle X-ray scattering and HR-TEM. Confocal microscopy and flow cytometric studies show that AuNP-LP complex has higher cellular uptake in SSTR2 expressed cancer cells (MCF-7 and AR42J) than in CHO cells. The enhanced cellular uptake of LP coated AuNPs lead to ~1.5 to 2-fold GSH depletion and enhanced ROS generation in MCF-7 cells. The preferential cytotoxicity of the AuNP-LP complex towards MCF-7 and AR42J cells, as revealed by MTT assay, is consistent with the increased cellular uptake. Our studies demonstrate that LP coated AuNP can be used as an effective platform to selectively target SSTR2 positive cancer cells for combination therapy approaches involving gold nanoparticles.

EDA2R mediates podocyte injury in high glucose milieu

EDA2R is a member of the large family of tumor necrosis factor receptor (TNFR). Previous studies suggested that EDA2R expression might be increased in the kidneys of diabetic mice. However, its mRNA and protein expression in kidneys were not analyzed; moreover, its role in the development of diabetic kidney disease was not explored. Here we analyzed the mRNA and protein expressions of EDA2R in diabetic kidneys and examined its role in the podocyte injury in high glucose milieu. By analysis with real-time PCR, Western blotting, we found that both the mRNA and protein levels of EDA2R were increased in the kidneys of diabetic mice. Immunohistochemical studies revealed that EDA2R expression was enhanced in both glomerular and tubular cells of diabetic mice and humans. In vitro studies, high glucose increased EDA2R expression in cultured human podocytes. Overexpression of EDA2R in podocytes promoted podocyte apoptosis and decreased nephrin expression. Moreover, ED2AR increased ROS generation in podocytes, while inhibiting ROS generation attenuates EDA2R-mediated podocyte injury. In addition, EDA2R silencing partially suppressed high glucose-induced ROS generation, apoptosis, and nephrin decrease. Our study demonstrated that high glucose increases EDA2R expression in kidney cells and that EDA2R induces podocyte apoptosis and dedifferentiation in high glucose milieu partially through enhanced ROS generation.

DNA Strand Break Properties of Protoporphyrin IX by X-Ray Irradiation against Melanoma.

Recent reports have suggested that 5-aminolevulinic acid (5-ALA), which is a precursor to protoporphyrin IX (PpIX), leads to selective accumulation of PpIX in tumor cells and acts as a radiation sensitizer in vitro and in vivo in mouse models of melanoma, glioma, and colon cancer. In this study, we investigated the effect of PpIX under X-ray irradiation through ROS generation and DNA damage. ROS generation by the interaction between PpIX and X-ray was evaluated by two kinds of probes, 3′-(p-aminophenyl) fluorescein (APF) for hydroxyl radical (•OH) detection and dihydroethidium (DHE) for superoxide (O2•-). •OH showed an increase, regardless of the dissolved oxygen. Meanwhile, the increase in O2•- was proportional to the dissolved oxygen. Strand breaks (SBs) of DNA molecule were evaluated by gel electrophoresis, and the enhancement of SBs was observed by PpIX treatment. We also studied the effect of PpIX for DNA damage in cells by X-ray irradiation using a B16 melanoma culture. X-ray irradiation induced γH2AX, DNA double-strand breaks (DSBs) in the context of chromatin, and affected cell survival. Since PpIX can enhance ROS generation even in a hypoxic state and induce DNA damage, combined radiotherapy treatment with 5-ALA is expected to improve therapeutic efficacy for radioresistant tumors.

Assessment of ZnO-NPs toxicity in maize: An integrative microRNAomic approach

Rapid expansion of nanotechnology and indiscriminate discharge of metal oxide nanoparticles (NPs) into the environment pose a serious hazard to the ecological receptors including plants. To better understand the role of miRNAs in ZnO-NPs stress adaptation, two small RNA libraries were prepared from control and ZnO-NPs (800 ppm, <50 nm particle size) stressed maize leaves. Meager performance of ZnO-NPs treated seedlings was associated with elevated tissue zinc accumulation, enhanced ROS generation, loss of root cell viability, increased foliar MDA content, decrease in chlorophyll and carotenoids contents. Deep sequencing identified 3 (2 known and 1 novel) up- and 77 (73 known and 4 novel) down-regulated miRNAs from ZnO-NPs challenged leaves. GO analysis reveals that potential targets of ZnO-NPs responsive miRNAs regulate diverse biological processes viz. plant growth and development (miR159f-3p, zma_18), ROS homeostasis (miR156b, miR166l), heavy metal transport and detoxification (miR444a, miR167c-3p), photosynthesis (miR171b) etc. Up-regulation of SCARECROW 6 in ZnO-NPs treated leaves might be responsible for suppression of chlorophyll biosynthesis leading to yellowing of leaves. miR156b.1 mediated up-regulation of CALLOSE SYNTHASE also does not give much protection against ZnO-NPs treatment. Taken together, the findings shed light on the miRNA-guided stress regulatory networks involved in plant adaptive responses to ZnO-NPs stress.

The Cytoprotective and Anti-cancer Potential of Bisbenzylisoquinoline Alkaloids from Nelumbo nucifera.

Natural product therapy has been gaining therapeutic importance against various diseases, including cancer. The failure of chemotherapy due to its associated adverse effects promoted adjunct therapy with natural products. Phytochemicals exert anti-carcinogenic activities through the regulation of various cell signaling pathways such as cell survival, inflammation, apoptosis, autophagy and metastasis. The 'small molecule-chemosensitizing agents' from plants induce apoptosis in drug-resistant and host-immune resistant cancer cells in in vitro as well as in vivo models. For example, alkaloids from Nelumbo nucifera, liensinine, isoliensinine and neferine exert the anticancer activity through enhanced ROS generation, activation of MAP kinases, followed by induction of autophagy and apoptotic cell death. Likewise, these alkaloids also exert their cytoprotective action against cerebrovascular stroke/ischemic stroke, diabetes, and chemotherapy-induced cytotoxicity. Therefore, the present review elucidates the pharmacological activities of these bisbenzylisoquinoline alkaloids which include the cytoprotective, anticancer and chemosensitizing abilities against various diseases such as cardiovascular diseases, neurological diseases and cancer.

Disrupted intracellular redox balance with enhanced ROS generation and sensitive drug release for cancer therapy.

In this paper, a nanocomposite was constructed to achieve improved photodynamic therapy (PDT) via disrupting the redox balance in cancer cells. Firstly, Sb2Se3 nanorods were synthesized as a new photosensitizer, displaying high photothermal conversion efficiency (45.2%) and reactive oxygen species (ROS) production due to the narrow band gap (1.1 eV) and a good NIR response. Moreover, the mechanism was investigated, demonstrating that dissolved O2 and photoinduced electrons manipulated ROS generation. Then, mesoporous silica was coated outside to improve the biocompatibility and to supply abundant space for the anticancer drug (doxorubicin, DOX). The sensitive Se-Se linker was grafted outside via a silane coupling reaction to block DOX molecules in the mesopores. As we know, the Se-Se group is sensitive to GSH, which can induce Se-Se linker bond breakage and targeted drug release due to the high expression of GSH in tumor cells. What is more, the consumption of intracellular GSH can also disrupt the redox balance in cancer cells, which would promote the PDT efficiency. The high-Z element of Sb possesses a high X-ray attenuation coefficient, giving the composite high contrast in CT imaging. This is associated with thermal imaging and multi-therapy (PDT/PTT/chemotherapy) to reveal the potential application to cancer treatment.