In Vivo Activation of Pro-Protein Therapeutics via Chemically Engineered Enzyme Cascade Reaction
Xiaoti Yang, Jin Chang, Ying Jiang, Qiaobing Xu, Ming Wang, Lanqun Mao
Abstract
Open AccessCCS ChemistryRESEARCH ARTICLE1 Feb 2021In Vivo Activation of Pro-Protein Therapeutics via Chemically Engineered Enzyme Cascade Reaction Xiaoti Yang, Jin Chang, Ying Jiang, Qiaobing Xu, Ming Wang and Lanqun Mao Xiaoti Yang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190 University of Chinese Academy of Sciences, Beijing 100049 , Jin Chang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190 University of Chinese Academy of Sciences, Beijing 100049 , Ying Jiang College of Chemistry, Beijing Normal University, Beijing 100875 , Qiaobing Xu Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155. , Ming Wang *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190 University of Chinese Academy of Sciences, Beijing 100049 and Lanqun Mao *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190 University of Chinese Academy of Sciences, Beijing 100049 https://doi.org/10.31635/ccschem.020.202000224 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Selective and temporal control over protein activity is of great importance for the advancement of the protein of interest into precise molecular medicine. Simply installing synthetic ligands to proteins for activity regulation, however, is often obscured by either nonspecificity or insufficient efficiency. This study reports a chemical approach in which enzymatic cascade reactions were designed for selective activation of pro-protein both in vitro and in vivo. Specifically, the system consisted of aromatic boronic-acid-modified nanoparticles, reactive oxygen species (ROS)-responsive pro-protein (RNase A-NBC), a small molecule drug, β-Lapachone (β-Lap), and strategically screened synthetic lipids, required for the assembly of the nanocomplexes. Once target-delivered into tumor cells, the reduction of β-Lap produces massive H2O2 in response to NAD(P)H quinone oxidoreductase 1 (NQO1), a tumor-specific enzyme, which triggers further induction by selective chemical modification of ROS-responsive cytosolic protein ribonuclease A (RNase A)-NBC, thus, switching from "inert" pro-protein to active therapeutics, that ultimately prohibit tumor cell growth. Moreover, the designed enzymatic cascade activation of the pro-protein was effective in vivo, displaying superior therapeutic efficacy to either the pro-protein alone or the β-Lap via tumor-targeted delivery and the consequent suppression of the tumor growth. As both RNase A and β-Lap have been evaluated clinically as antitumor therapeutics, our chemical multi-step cascade methodology is, therefore, a promising strategy for selective modulation of pro-protein chemistry in the living system for fundamental investigations, favorable toward potential anticancer applications. Download figure Download PowerPoint Introduction Proteins are essential biomacromolecules that execute diverse functionalities for the regulation of cell fate and life cycle.1 The abnormal expression or dysfunction of intracellular proteins could result in complicated biological consequences and cause various diseases, including cancers.2 Therefore, supplementing disease cells with functional proteins to compensate those that are dysregulated is the most straightforward strategy for cell manipulation and disease treatment.3 The past decade has witnessed great success in developing protein-based biotherapeutics for diverse clinical purposes, including the immune checkpoint inhibitors, PD-1, and PD-L1 antibodies, for cancer immunotherapy.4,5 However, one challenge associated with protein therapy is the lack of control of the protein activity in a selective manner for targeted disease treatment.6–8 In particular, superior selective control of protein activity that stays "inert" until "activation" by exogenous stimuli or endogenous biomarkers of malignant cells is highly desired, but this technique remains extremely limited.9,10 In this regard, pro-proteins that could switch between the "inert" and "active" states under the influence of the endogenous species of disease cells (e.g., tumor metabolites, intracellular enzymes), particularly, those that would show specific response in the intracellular malignant cells microenvironment, are imperative for the advancement of targeted protein therapy.11–14 In the past four years, we and several others have demonstrated highly-efficient designed chemical approaches to control protein conjugation and activity to enable manipulation of cellular function for therapeutic applications.9,15–21 We have reported previously that the conjugation of stimulus-responsive chemical moieties to proteins could deactivate these proteins temporarily and make them (pro-proteins) stay "inert."10,11,22,23 Subsequently, in the presence of either exogenous stimuli or endogenous chemical triggers, the pro-proteins switched to "active" state by removal of the chemical tags. A wide variety of chemical techniques have been used to control protein activity following this strategy; however, their potential for developing pro-protein therapeutics in response to the intracellular microenvironment of the malignant cells is lacking, mostly due to the low effectiveness and alterations in selectivity during proteins switch from "inert" state to "active" state inside the malignant cells, both in vitro and in vivo.12 Natural systems have evolved multiple enzyme-initiated cascade reactions, for instance, post-translational modifications (PTMs) to switch protein activity selectively and the transduction of upstream cell signals into cell phenotypic changes.24 Therefore, we envisioned that regulating the chemical modification of proteins via integration of intracellular environmental factors and enzymatic cascade reactions would be of great appeal for the spatiotemporal control of protein activity in living cells and the development of novel pro-protein therapeutics.25 In this study, we report the first example of controlling the chemical conjugation and activity of pro-protein using tumor-cell-selective enzymatic cascade reactions and the subsequent potential of this cascade system in the development of targeted protein therapy. We show the design of the encapsulated nanoprodrug targeted delivery into the tumor cells and the subsequent cascade of enzymatic reactions that led to the pro-protein activation, as displayed in the illustration of Figure 1. We employed the NAD(P)H quinone oxidoreductase 1 (NQO1), an enzyme that is overexpressed in tumor cells, which catalyzes the futile reduction of β-Lapachone (β-Lap) to generate massive reactive oxygen species (ROS).26,27 We were able to utilize this NQO1 reaction to control the chemical modification of boronic-acid-conjugated ROS-responsive pro-protein, RNase A-NBC, in a cascade manner, to switch its activity from the "inert" to the "active" state (Figure 1). Moreover, to enable an in vivo pro-protein activation within the tumor cells, we designed the cascade system to feature RNase A-NBC, β-Lap, and strategically screened synthetic lipids that could assemble nanoparticles to aid the codelivery of the pro-protein and β-Lap simultaneously into the targeted tumor cells. Once delivered, the reduction of β-Lap could amplify intracellular H2O2 level in response to the cellular specific NQO1, which further switches the "inert" RNase A-NBC to active therapeutics, thereby, bringing about the selective prohibition of the tumor cell growth. Furthermore, the engineered enzymatic cascade reaction displayed superior therapeutic efficacy than either the pro-protein alone or the β-Lap alone delivered in vivo to suppress the tumor growth. As both RNase A and β-Lap have been validated clinically as antitumor therapeutics, our chemical methodology is, therefore, a promising strategy for selective modulation of protein chemistry in the living system for fundamental research purposes and the achievement of potential anticancer applications. Figure 1 | (a) NQO1-catalyzed futile redox cycle of β-Lapachone (β-Lap) to generate massive ROS that activates the pro-protein, RNase A-NBC, in living cells. (b) Nanoparticle formulation facilitates simultaneous delivery of RNase A-NBC and β-Lap into NQO1-overexpressed tumor cells for pro-protein activation in vivo. Schematic illustration of pro-protein activation in vitro and in vivo. Download figure Download PowerPoint Experimental Method Materials and Methods All chemicals used for the organic syntheses, including dicoumarol and bovine pancreatic ribonuclease A (RNAse A), were purchased from Sigma-Aldrich (St. Louis, MO, USA). NAD(P)H quinone oxidoreductase 1 (NQO1), β-Lapachone (β-Lap), and 2,3-dimethoxy 1,4-naphthoquinone (DMNQ) were obtained from Abcam (Boston, USA). 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-Tetrazolium (WST-1) was purchased from BioVision (Milpitas, USA). Nicotinamide adenine dinucleotide (NADH) was purchased from Calbiochem (La Jolla, CA). Chemically-modified RNase A-NBC was prepared by reacting RNase A with an excess amount of 4-nitrophenyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl carbonate.10 The siRNA targeting human NQO1 (CCGUACACAGAUACCUUGA) was synthesized by BIOSYNTHCH (Suzhou, China). All animal care and experimental procedures were approved by the Institutional Animal Care and Use Committees (IUCAC), National Center for Nanoscience and Technology of China (NCNTC). RNase A-NBC activation driven by NQO1-initiated catalytic reduction of β-Lap To verify that the NQO1-catalyzed redox cycle of β-Lap could generate H2O2 to activate RNase A-NBC in situ, RNase A-NBC (13.3 μg/mL) was incubated with β-Lap (0.33 μM) and NQO1 (0.32 ng/mL) in the presence of NADH (1.33 mM) in Dulbecco's phosphate-buffered saline (DPBS) at 37 °C for 2 h. The enzyme activity of the reaction mixture was assayed using a commercial RNase A assay kit and the RNaseAlert Nuclease Detection System (Integrated DNA Technologies, IA, USA). The RNase A detection was monitored using plate reader (BioTek, synergy H1M, USA) at 520 nm emission wavelength, and the results were compared with that of RNase A-NBC reaction without the addition of the β-Lap reducer NQO1, or both NQO1 and the H2O2 inducer β-Lap). Meanwhile, to further confirm the specificity of NQO1-catalyzed β-Lap reduction in restoring RNase A-NBC activity, an inhibitor of NQO1, dicoumarol (250 μM), was mixed with RNase A-NBC, β-Lap, and NQO1 under the same reaction conditions for the RNase A activity assay. Lipid/RNase A-NBC/β-lap nanoparticle preparation To prepare lipid nanoparticle encapsulating RNase A-NBC and β-Lap, lipid nanoparticles, EC16-80, and the polystyrene polymer, 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), were mixed at a weight ratio of 4∶1 in chloroform, to which 1 × 10−7 mol of β-Lap was added. After evaporating the organic solvent under vacuum, the resulted thin layer film was hydrated using DPBS with the aid of bath sonication. Subsequently, 100 μg RNase A-NBC was added into the solution mentioned above along with 200 μg of the polyethylene glycol conjugated phospholipid stabilizer, DSPE-mPEG2000. The final concentration of the lipid in the nanoparticle formulation was 1 mg/mL. The size and morphology of the final micellar EC16-80/RNase A-NBC/β-Lap nanoparticles were characterized using dynamic light scattering (DLS) measurement, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Cell culture All cells used in this study were purchased from National Infrastructure of Cell Line Resource (Beijing, China) and maintained in high-glucose Dulbecco's modified eagle medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin at 37 °C in the presence of 5% CO2. For the intracellular delivery, the cells were subcultured and seeded in 96-well or 48-well plates for 24 h prior to the experiment. DMEM, FBS, and penicillin/streptomycin were purchased from Gibco (NY, USA). Intracellular ROS assay of MCF-7 cells treated with EC16-80/RNase A-NBC/β-Lap nanoparticle The intracellular ROS level of breast cancer MCF-7 cells with and without the formulated nanoparticle (EC16-80/RNase A-NBC/β-Lap) treatment was measured using 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA) staining, followed by flow cytometry analysis. MCF-7 cells were seeded in a 24-well plate at a density of 5×104/well and treated with EC16-80/RNase A-NBC/β-Lap nanoparticle (Group 1) or without treatment (Group 2) for 12 h. At the end of the incubation, the cells were harvested, washed by DPBS, stained with DCFDA (1 μM), and immediately subjected to flow cytometry analysis on a Beckman Coulter CytoFLEX (Beckman Coulter, USA). Cell uptake study of EC16-80/RNase A-NBC/β-Lap nanoparticles For the cellular uptake study of EC16-80/RNase A-NBC/β-Lap nanoparticles, the RNase A-NBC was labeled with fluorescein isothiocyanate (FITC) before use. Briefly, 2 mg RNase A-NBC dissolved in 750 μL of sodium bicarbonate solution (0.1 M, pH = 9.5) was mixed with 250 μL of freshly prepared FITC solution (4 mg/mL in DMSO). Then the reaction mixture was stirred at room temperature for 2 h with protection from light. The resulted FITC-labeled RNase A-NBC was purified by size exclusion chromatography (SEC) on a PD-10 desalting column (GE Healthcare, MA, USA). To study the cellular uptake of EC16-80/RNase A-NBC/β-Lap nanoparticles, MCF-7 cells were seeded at a density of 1.5 × 105 cells/well in glass-bottom cell culture dishes (NEST Biotechnology, Wuxi, China) or 2.5 × 104 cells/well in 48-well plates for 24 h before the experiment and then treated with EC16-80/RNase A-NBC/β-Lap nanoparticles (at varying protein concentration, as indicated) for 8 h at 37 °C. At the end of incubation, the cells were washed twice thoroughly with 0.1% heparin solution, followed by confocal laser scanning microscopy (CLSM) imaging on OLYMPUS FV1000-IX81 or by flow cytometry analysis. Intracellular delivery of EC16-80/RNase A-NBC/β-Lap nanoparticles for targeted cancer therapy To verify the delivery of EC16-80/RNase A-NBC/β-Lap nanoparticles that can activate RNase A-NBC in live cells to prohibit tumor cell proliferation, a variety of cancerous cells, including MCF-7 (breast cancer), A549 (human alveolar basal epithelial adenocarcinoma), HeLa (human cervical cancer), and SiHa (human cervical cancer) cell lines, were seeded in 96-well plates at a density of 1 × 104 cells per well 24 h before the prodrug delivery experiment. On the day of the experiment, EC16-80/RNase A-NBC/β-Lap nanoparticles were added directly to the cell cultures, with the final RNase A-NBC concentration increasing from 0.17 to 1.0 μg/mL. After 8 h incubation, the mixtures were replaced with fresh cell culture medium, followed by another 3 days of cell culture. Subsequently, the cell viability was measured by an MTT assay. We excluded the potential of any cytotoxic effects of the empty EC16-80, EC16-80/β-Lap, or EC16-80/RNase A-NBC nanoparticles by adding these individual nanoparticle formulations as controls to each plated cell culture group under the same experimental conditions alongside that of EC16-80/RNase A-NBC/β-Lap nanoparticle (test) system. Then we investigated whether an NQO1-catalyzed cascade reaction could selectively activate RNase A-NBC in cancer cells by adding three noncancerous cell lines, including HEK-293 T (human embryonic kidney SV40 mutant large T antigen), HK-2 (human immortalized proximal tubule epithelial), and NIH-3T3 (murine fibroblast) cells to our four cancer cell lines in the assay. We seeded each of the seven cell types in a 48-well plate at a density of 2.5 × 104 cells/well. The plated cells were treated with the different nanoparticle formulations under the same conditions, and the cell viabilities were measured in each group using an alamarBlue assay. Further, we confirmed the effect of intracellular NQO1 on RNase A-NBC activation in live cells by treating SiHa cells with small interfering (si)NQO1 to study its impact on the knockdown of endogenous NQO1 expression. Briefly, SiHa cells were seeded in 48-well plates at a density of 1.8 × 104 cells/well for 24 h before the delivery experiment. On the day of the experiment, a mixture of siNQO1 and Lipofectamine 2000 (Life Technology, USA) was added directly to SiHa cells at concentrations of 80 nM for siNQO1 and 2.7 μg/mL for Lipofectamine 2000. After 10 h incubation, the mixtures were replaced with fresh cell culture medium for another 6 h. EC16-80/RNase A-NBC/β-Lap nanoparticles were added to the siNQO1 pretreated SiHa cells at final concentrations of 0.4 μg/mL RNase A-NBC and 1.6 μg/mL of EC16-80. After 6 h of further incubation, the mixtures were replaced with fresh cell culture medium, and an alamarBlue assay was performed to measure cell viability. Endogenous NQO1 activity assay We evaluated the endogenous NQO1 expression level in cancerous and noncancerous cells by measuring the activity of NQO1 in the lysates of the seven cell lines under study using a reported method.28 Briefly, each sample of cell lysate containing 25 ng/mL proteins was added to a mixed solution of 10 μM WST-1 tetrazolium salt and 400 μM NADH. Subsequently, 10 μM DMNQ (a redox-cycling reagent) was added to initiate the assay reaction. The absorption of the reaction mixture at 450 nm was monitored for 1 h. In vivo delivery of EC16-80/RNase A-NBC/β-Lap nanoparticles First, we developed MCF-7 tumor-bearing xenograft using 8 × 106 MCF-7 cells suspended in 200 μL DPBS and injecting subcutaneously in the left axilla region of 4-week-old female NuNu nude mice (purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd). Then we investigated an in vivo distribution of EC16-80/FITC-RNase A-NBC/β-Lap nanoparticles by injection of 200 μL of the prodrug into the MCF-7 tumor-bearing mice (n = 3) when the tumor size reached ∼ 500 mm3. The experimental setup with appropriate controls was as follows–Group 1: EC16-80/FITC-RNase A-NBC/β-Lap, Group 2: EC16-80/FITC-RNase A-NBC nanoparticle, and Group 3: free FITC-RNase A-NBC. At 4 h posttreatment, the mice were sacrificed, and the major organs of mice in the different groups were collected for fluorescence imaging on an IVIS small animal imaging system (PerkinElmer, USA). Second, following the in vivo prodrug delivery, tumor growth suppression study was performed when the mice tumor size reached ∼ 100 mm3 in volume. The mice were divided into 4 groups and the prodrug or the controls were injected intravenously, as follows–Group 1: DPBS alone, Group 2: EC16-80/β-Lap nanoparticles, Group 3: EC16-80/RNase A-NBC nanoparticles, and Group 4: EC16-80/β-Lap/RNase A-NBC nanoparticles. The mice in each group received an injection every 2 days until a total of five doses. The composition of each item within the injected nanoparticles was 9 mg/kg EC16-80, 1.1 mg/kg RNase A–NBC, or 0.27 mg/kg β-Lap. Each tumor size and mouse weight was measured in each group every 2 days, and the tumor volume was calculated by the formula 1/2 × lengh (mm) × width2 (mm). At the end of the experiment, blood samples were collected from each mice group, and serum from each group was prepared for hepatocellar function biomarker analysis, including the determination of aspartate transaminase (AST), alanine transaminase (ALT), and total bilirubin using the respective commercial assay kit (Nanjing Jiancheng Bioengineering institute, Nanjing, China). Results and Discussion NQO1-initiated cascade activation of ROS-responsive RNase A-NBC In this study, we selected Ribonuclease A (RNase A) as a model protein because its role in cancer therapy has been evaluated previously in clinical trials and shown to act via the cleavage of intracellular RNA after cellular entry and the subsequent induction of cytotoxic effects.29 Enzymatic activation of RNase A could, therefore, be of great appeal and potential for developing pro-proteins for targeted cancer therapy. The chemically modified "inert" pro-protein, RNase A-NBC (Figure 1a), was prepared by conjugating a ROS-responsive moiety, aromatic boronic acid, to RNase A according to our previous report.10 The chemical conjugation of aromatic boronic acid is a practical approach to develop pro-proteins19 and prodrugs,30 making use of ROS-triggered biorthogonal boronic acid oxidation and cleavage.31 The effectiveness of using endogenous ROS to regulate pro-proteins in vivo, however, might not be sufficiently significant due to the heterogeneity of tumors, which, in turn, display various ROS levels, leading to variations in pro-protein activation. Thus, developing new approaches to activate ROS-responsive pro-proteins in vivo and to advance further its therapeutic potential is highly desirable.8 NQO1 could catalyze a futile redox cycle of β-Lap to generate massive ROS in short periods, for example, of H2O2 per of β-Lap in 2 Therefore, we that in H2O2 by NQO1-catalyzed futile reduction of β-Lap could result in a switch of RNase A-NBC from an "inert" state to an "active" state by the chemical conjugated to the RNase We this by RNase A-NBC (13.3 μg/mL) with NQO1 (0.32 ng/mL) and β-Lap (0.33 μM) for 2 h. laser analysis and RNase A activity assay were performed to confirm the and the of the enzyme protein As shown in Figure the molecular weight of RNase A-NBC was from to after a reaction NQO1 and β-Lap the and removal of groups from RNase A-NBC. Meanwhile, the RNase A activity assay extremely ribonuclease activity of RNase A-NBC as a result of the chemical modification of an essential of RNase A (Figure The treatment of RNase A-NBC with NQO1 and β-Lap, however, the RNase activity to due to the of the active compared with the This activity was NQO1 concentration which was when varying concentrations of NQO1 were incubated with a amount of RNase A-NBC under the same experimental Moreover, when a inhibitor of was added to the reaction mixture of RNase A-NBC, NQO1, and β-Lap, of RNase activity was (Figure as NQO1 was to the enzyme to the active This confirmed the effectiveness and selectivity of NQO1-catalyzed β-Lap reduction for the of RNase A activity via the removal of from RNase A-NBC Figure 2 | Enzyme activity assay of RNase A-NBC measured on a at an emission of 520 nm over a 1 h with and without the treatment of NQO1 or both NQO1 and β-Lap. μg/mL RNase A-NBC was incubated with μM β-Lap and different concentrations of NQO1 in the presence of NADH. To study the effect of dicoumarol on NQO1-initiated RNase A-NBC activation, 250 μM dicoumarol was added to the reaction mixture of μg/mL RNase A-NBC, μM β-Lap, and ng/mL NQO1 before Download figure Download PowerPoint Enzymatic activation of RNase A-NBC in living cells we whether the NQO1-catalyzed β-Lap reduction and RNase A-NBC activation were effective in living cells and the potential of active RNase A-NBC to prohibit tumor cell growth. To this RNase A-NBC and β-Lap to be delivered into cells simultaneously to initiate the enzymatic cascade reaction. the therapeutic and of proteins are by their cellular to regulate cell delivery of proteins is of for the advancement of protein chemistry in to effective protein we used a EC16-80, which been developed for effective protein was screened from a of lipid for simultaneous delivery of RNase A-NBC and β-Lap into cells (Figure In the lipid nanoparticle RNase A-NBC was encapsulated via with EC16-80, β-Lap was in the layer of the lipid nanoparticles (Figure analysis Figure that the EC16-80/RNase A-NBC/β-Lap nanoparticles a size of ∼ nm in which was to that of the empty nanoparticles, or nanoparticles encapsulated with the RNase A-NBC or the β-Lap a effect of the of RNase A-NBC and β-Lap on the of the The of EC16-80/RNase A-NBC/β-Lap nanoparticles from to compared with that of the empty nanoparticles, that the of the RNase A-NBC the of the lipid nanoparticles. Meanwhile, four types of and RNase A-NBC nanoparticle as by (Figure 3) and imaging Figure Figure 3 | of different (a) alone, (b) EC16-80/β-Lap nanoparticles, EC16-80/RNase A-NBC nanoparticles, and EC16-80/RNase A-NBC/β-Lap nanoparticles. 1 Download figure Download PowerPoint The intracellular delivery of EC16-80/RNase A-NBC/β-Lap nanoparticles was monitored by MCF-7 cells with FITC-labeled RNase A-NBC and characterized further with confocal laser imaging as well as flow As shown in Figure the treatment of MCF-7 cells with EC16-80/FITC-RNase A-NBC/β-Lap nanoparticles resulted in a of fluorescence in the cytometry analysis Figure that than of the MCF-7 cells were with the EC16-80/FITC-RNase A-NBC/β-Lap nanoparticles at a protein concentration of μg/mL in a to that of EC16-80/FITC-RNase A-NBC nanoparticles, a effect of the delivery of the β-Lap on RNase A-NBC. Moreover, we that the intracellular ROS level of MCF-7 cells treated with EC16-80/RNase A-NBC/β-Lap nanoparticles was compared with the cells or the alone treated cells or the EC16-80/RNase A-NBC nanoparticles without β-Lap treated cells Figure This result was of an delivered β-Lap by the EC16-80/RNase A-NBC/β-Lap nanoparticles which NQO1-catalyzed reduction to generate massive ROS that further the and subsequent activation of RNase A-NBC in the live cells, as further Figure 4 | (a) of MCF-7 cells treated with EC16-80/FITC-RNase A-NBC/β-Lap nanoparticles μg/mL lipid 10 (b) of MCF-7 cells treated with different lipid nanoparticle