scholarly journals Atovaquone-HSA Nano-drugs Enhance the Efficacy of PD-1 Blockade Immunotherapy by Improving Hypoxic Tumor Microenvironment

Author(s):  
Simeng Wang ◽  
Xinrui Zhou ◽  
Zekun Zeng ◽  
Mengjun Sui ◽  
Lihong Chen ◽  
...  

Abstract Background: Hypoxia is inherent character of most solid malignancies, leading to the failure of chemotherapy, radiotherapy and immunotherapy. Atovaquone, an anti-malaria drug, can alleviate tumor hypoxia by inhibiting mitochondrial complex Ⅲ activity. The present study exploits atovaquone/albumin nanoparticles to improve bioavailability and tumor targeting of atovaquone, enhancing the efficacy of anti-PD-1 therapy by normalizing tumor hypoxia.Methods: We prepared atovaquone-loaded human serum albumin (HSA) nanoparticles stabilized by intramolecular disulfide bonds, termed HSA-ATO NPs. The average size and zeta potential of HSA-ATO NPs were measured by particle size analyzer. The morphology of HSA-ATO NPs was characterized by transmission electron microscope (TEM). The bioavailability and safety of HSA-ATO NPs were assessed by animal experiments. Immunofluorescence and ELISA assays were used to evaluate tumor immune microenvironment.Results: Our data first verified that atovaquone effectively alleviated tumor hypoxia by inhibiting mitochondrial activity both in vitro and in vivo, and successfully encapsulated atovaquone in vesicle with albumin, forming HSA-ATO NPs of approximately 164 nm in diameter. We then demonstrated that the HSA-ATO NPs possessed excellent bioavailability, tumor targeting and a highly favorable biosafety profile. When combined with anti-PD-1 antibody, we observed that HSA-ATO NPs strongly enhanced the response of mice bearing tumor xenografts to immunotherapy. Mechanistically, HSA-ATO NPs promoted intratumoral CD8+ T cell recruitment by improving tumor hypoxia microenvironment, thereby enhancing the efficacy of anti-PD-1 immunotherapy. Conclusion: Our data provide strong evidences showing that HSA-ATO NPs can serve as safe and effective nano-drugs to enhance cancer immunotherapy by improving hypoxic tumor microenvironment.

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Simeng Wang ◽  
Xinrui Zhou ◽  
Zekun Zeng ◽  
Mengjun Sui ◽  
Lihong Chen ◽  
...  

Abstract Background Hypoxia is inherent character of most solid malignancies, leading to the failure of chemotherapy, radiotherapy and immunotherapy. Atovaquone, an anti-malaria drug, can alleviate tumor hypoxia by inhibiting mitochondrial complex III activity. The present study exploits atovaquone/albumin nanoparticles to improve bioavailability and tumor targeting of atovaquone, enhancing the efficacy of anti-PD-1 therapy by normalizing tumor hypoxia. Methods We prepared atovaquone-loaded human serum albumin (HSA) nanoparticles stabilized by intramolecular disulfide bonds, termed HSA-ATO NPs. The average size and zeta potential of HSA-ATO NPs were measured by particle size analyzer. The morphology of HSA-ATO NPs was characterized by transmission electron microscope (TEM). The bioavailability and safety of HSA-ATO NPs were assessed by animal experiments. Flow cytometry and ELISA assays were used to evaluate tumor immune microenvironment. Results Our data first verified that atovaquone effectively alleviated tumor hypoxia by inhibiting mitochondrial activity both in vitro and in vivo, and successfully encapsulated atovaquone in vesicle with albumin, forming HSA-ATO NPs of approximately 164 nm in diameter. We then demonstrated that the HSA-ATO NPs possessed excellent bioavailability, tumor targeting and a highly favorable biosafety profile. When combined with anti-PD-1 antibody, we observed that HSA-ATO NPs strongly enhanced the response of mice bearing tumor xenografts to immunotherapy. Mechanistically, HSA-ATO NPs promoted intratumoral CD8+ T cell recruitment by alleviating tumor hypoxia microenvironment, thereby enhancing the efficacy of anti-PD-1 immunotherapy. Conclusions Our data provide strong evidences showing that HSA-ATO NPs can serve as safe and effective nano-drugs to enhance cancer immunotherapy by alleviating hypoxic tumor microenvironment. Graphic abstract


2021 ◽  
Author(s):  
Weijuan Zou ◽  
Junnian Hao ◽  
Jianrong Wu ◽  
Xiaojun Cai ◽  
Bing Hu ◽  
...  

Abstract Backgrounds: Sonodynamic therapy (SDT) as an emerging reactive oxygen species (ROS)-mediated antitumor means is still hampered by the rapid depletion of oxygen, as well as hypoxic tumor microenvironment. Instead of the currently coping strategies through amplifying endogenous O2 level, herein, a biodegradable O2 economizer is described as a reduce expenditure bioreactor for augmenting SDT efficacy. Results: We have successfully fabricated the O2 economizer (HMME@HMONs-3BP-PEG, HHBP) by the conjugation of respiration inhibitor 3-bromopyruvate (3BP) with hollow mesoporous organosilica nanoparticles (HMONs), followed by the loading of organic sonosensitizers (HMME) and further surface modification of poly(ethylene glycol) (PEG). The engineered HHBP features controllable pH/GSH/US-sensitive drug release. The exposed 3BP could effectively inhibit cell respiration for restraining the oxygen consumption, which could alleviate the tumor hypoxia. More interestingly, it could exorbitantly elevate the autophagy level, which in turn induce excessive activation of autophagy for promoting the therapeutic efficacy. As a result, accompanied with suppressing O2-consumption and triggering pro-death autophagy strategy, the HHBP achieves remarkable antitumor activity, which has been systematically validated both in vivo and in vitro assays. Conclusion: This work not only provides a reduce expenditure strategy for enduring SDT, but also represents an inquisitive strategy for tumor treatments via inducing pro-death autophagy.


2021 ◽  
Author(s):  
Alexander M.A. van der Wiel ◽  
Victoria Jackson-Patel ◽  
Raymon Niemans ◽  
Ala Yaromina ◽  
Emily Liu ◽  
...  

Abstract Background Hypoxia-activated prodrugs (HAPs) are a promising class of antineoplastic agents that can selectively eliminate hypoxic tumor cells. The present study evaluates the hypoxia-selectivity and antitumor activity of CP-506, a DNA alkylating HAP with favorable pharmacological properties. Methods Stoichiometry of reduction, one-electron affinity, and back-oxidation rate of CP-506 were characterized by fast-reaction radiolytic methods. In vitro, 2D monolayer and 3D spheroid and multicellular layer cultures were used to investigate the hypoxia-selectivity of CP-506. In vivo, the causal relationship between tumor oxygenation and antitumor effects of CP-506 was assessed. Mice bearing a range of human tumor xenografts were exposed to CP-506 and tumor growth was monitored. A multivariate linear regression model was used to identify factors associated with CP-506 treatment outcome. Results Net reduction, metabolism, and cytotoxicity of CP-506 were maximally inhibited at oxygen concentrations above 1 µM (0.1% O2). CP-506 demonstrated cytotoxicity selectively in hypoxic 2D and 3D cell cultures with normoxic/anoxic IC50 ratios up to 203. In vivo, the antitumor effects of CP-506 were selective for hypoxic tumor cells and causally related to tumor oxygenation. CP-506 effectively decreased the hypoxic fraction and inhibited growth of a wide range of hypoxic xenografts. Two well-oxygenated models were refractory to treatment despite intrinsic anoxic sensitivity in vitro. A multivariate regression analysis revealed baseline tumor hypoxia and in vitro sensitivity to CP-506 to significantly correlate with treatment response. Conclusions Our results demonstrate that CP-506 selectively sterilizes hypoxic tumor cells and has broad antitumor activity. Our data also indicate that tumor hypoxia and cellular sensitivity to CP-506 are strong determinants of the antitumor effects of CP-506.


2021 ◽  
Vol 5 (3) ◽  
pp. 01-11
Author(s):  
Erlinda M. Gordon ◽  
Seiya Liu ◽  
Sant P. Chawla ◽  
Frederick L. Hall

Background and Rationale: Although PTX is widely used as a single chemotherapeutic agent and in various combination regimens, its clinical utility is hindered by acquired drug resistance and serious dose-limiting side effects that result from the ungoverned biodistribution of the taxane. Hypothesis: Conceptually, the precision, validity, and efficiency of paclitaxel delivery to tumor compartments might be substantially improved by “actively targeting” the exposed collagenous (XC-) proteins presented within the tumor microenvironment (TME)—XC-proteins physically exposed by the pathologic biochemical processes of tumor invasion, reactive stroma formation, and neo-angiogenesis. Objective: An adaptive bioengineering approach aims to apply pathotropic tumor-targeting functionality to paclitaxel (PTX), a powerful cytotoxic taxane which exhibits anti-tubulin / anti-mitotic / anti-cancer activities against a broad range of solid tumors. Materials and Methods: Synthetic peptide XC-targeting probes (< 40 aa) and polypeptide aptamers (40 to 53 aa), 85 - 99% purity, were prepared by 9-fluorenylmethyloxycarbonyl (Fmoc) solid phase peptide synthesis, purified by high performance liquid chromatography (HPLC), and verified by mass spectrometry and amino acid analysis, and the XC-targeting probes were FITC-labeled. Analysis of fluorescence in XC-binding assays was visualized with an Ultra Bright Blue Light trans-illuminator equipped with an amber filter; photo-documentation was provided by a Leica V-Lux 1 digital camera; and comparative fluorescence was quantified using a Quantus benchtop fluorimeter (Promega). The tumor-targeting properties of Taxol-Tropins were tested in vitro by Taxol-aptamer binding assays and collagen-agarose binding assays and the bioactivities of PTX bound non-covalently toTaxol-Tropin aptamers were tested on XC-agarose beads. Further, the tumor targeting property of the Taxol-Tropin aptamers was tested in vivo in a murine model of metastatic cancer. Results: Here we report on the first actively targeted delivery of paclitaxel utilizing bifunctional polypeptide targeting onco-aptamers, called Taxol-Tropins, which: (i) bind PTX upon simple mixing with suitably high affinities and; (ii) bind exposed XC-proteins, thereby promoting enhanced partitioning and drug delivery into the TME. The bifunctional peptide sequence-optimized Taxol-Tropins bound tightly non-covalently to PTX and also exhibited high affinity and selectivity for XC-agarose beads in vitro. Importantly, the cytotoxic bioactivity of the Taxol-Tropin-bound-PTX molecule was well preserved in cellulo, as was demonstrated by cytocidal activity observed in MDA-MB-231 breast cancer cell cultures. Tumor-targeted PTX delivery by Taxol-Tropin onco-aptamers in vivo was modeled by subcutaneous xenografts of human pancreatic cancer in nude mice: where intense fluorescence of the PTX probe was observed in tumors of mice injected with the Taxol-Tropin-bound-PTX within minutes after intravenous injection, but not in untreated mice or mice treated with non-targeted PTX probe. Conclusions: These results demonstrate the feasibility of pro-actively targeting PTX, a clinically important small molecule, using Taxol-Tropins: synthetic polypeptide onco-aptamers, revealing optimized drug binding sequences and structural modifications pertinent to further clinical development of the tumor-targeting platform which may indeed shift the Therapeutic Index of PTX to one of greater clinical efficacy at lower drug doses.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Weijuan Zou ◽  
Junnian Hao ◽  
Jianrong Wu ◽  
Xiaojun Cai ◽  
Bing Hu ◽  
...  

Abstract Backgrounds Sonodynamic therapy (SDT) as an emerging reactive oxygen species (ROS)-mediated antitumor strategy is challenged by the rapid depletion of oxygen, as well as the hypoxic tumor microenvironment. Instead of the presently available coping strategies that amplify the endogenous O2 level, we have proposed a biodegradable O2 economizer to reduce expenditure for augmenting SDT efficacy in the present study. Results We successfully fabricated the O2 economizer (HMME@HMONs-3BP-PEG, HHBP) via conjugation of respiration inhibitor 3-bromopyruvate (3BP) with hollow mesoporous organosilica nanoparticles (HMONs), followed by the loading of organic sonosensitizers (hematoporphyrin monomethyl ether; HMME) and further surface modification of poly(ethylene glycol) (PEG). The engineered HHBP features controllable pH/GSH/US-sensitive drug release. The exposed 3BP could effectively inhibit cell respiration for restraining the oxygen consumption, which could alleviate the tumor hypoxia conditions. More interestingly, it could exorbitantly elevate the autophagy level, which in turn induced excessive activation of autophagy for promoting the therapeutic efficacy. As a result, when accompanied with suppressing O2-consumption and triggering pro-death autophagy strategy, the HHBP could achieve the remarkable antitumor activity, which was systematically validated both in vivo and in vitro assays. Conclusions This work not only provides a reduce expenditure means for enduring SDT, but also represents an inquisitive strategy for tumor treatments by inducing pro-death autophagy. Graphical Abstract


2019 ◽  
Vol 19 (12) ◽  
pp. 950-960
Author(s):  
Soghra Farzipour ◽  
Seyed Jalal Hosseinimehr

Tumor-targeting peptides have been generally developed for the overexpression of tumor specific receptors in cancer cells. The use of specific radiolabeled peptide allows tumor visualization by single photon emission computed tomography (SPECT) and positron emission tomography (PET) tools. The high affinity and specific binding of radiolabeled peptide are focusing on tumoral receptors. The character of the peptide itself, in particular, its complex molecular structure and behaviors influence on its specific interaction with receptors which are overexpressed in tumor. This review summarizes various strategies which are applied for the expansion of radiolabeled peptides for tumor targeting based on in vitro and in vivo specific tumor data and then their data were compared to find any correlation between these experiments. With a careful look at previous studies, it can be found that in vitro unblock-block ratio was unable to correlate the tumor to muscle ratio and the success of radiolabeled peptide for in vivo tumor targeting. The introduction of modifiers’ approaches, nature of peptides, and type of chelators and co-ligands have mixed effect on the in vitro and in vivo specificity of radiolabeled peptides.


2020 ◽  
Vol 15 (3) ◽  
pp. 193-206
Author(s):  
Brognara Lorenzo ◽  
Salmaso Luca ◽  
Mazzotti Antonio ◽  
Di M. Alberto ◽  
Faldini Cesare ◽  
...  

Background: Chronic wounds are commonly associated with polymicrobial biofilm infections. In the last years, the extensive use of antibiotics has generated several antibiotic-resistant variants. To overcome this issue, alternative natural treatments have been proposed, including the use of microorganisms like probiotics. The aim of this manuscript was to review current literature concerning the application of probiotics for the treatment of infected chronic wounds. Methods: Relevant articles were searched in the Medline database using PubMed and Scholar, using the keywords “probiotics” and “wound” and “injuries”, “probiotics” and “wound” and “ulcer”, “biofilm” and “probiotics” and “wound”, “biofilm” and “ulcer” and “probiotics”, “biofilm” and “ulcer” and “probiotics”, “probiotics” and “wound”. Results: The research initially included 253 articles. After removal of duplicate studies, and selection according to specific inclusion and exclusion criteria, 19 research articles were included and reviewed, accounting for 12 in vitro, 8 in vivo studies and 2 human studies (three articles dealing with animal experiments included also in vitro testing). Most of the published studies about the effects of probiotics for the treatment of infected chronic wounds reported a partial inhibition of microbial growth, biofilm formation and quorum sensing. Discussion: The application of probiotics represents an intriguing option in the treatment of infected chronic wounds with multidrug-resistant bacteria; however, current results are difficult to compare due to the heterogeneity in methodology, laboratory techniques, and applied clinical protocols. Lactobacillus plantarum currently represents the most studied strain, showing a positive application in burns compared to guideline treatments, and an additional mean in chronic wound infections. Conclusions: Although preliminary evidence supports the use of specific strains of probiotics in certain clinical settings such as infected chronic wounds, large, long-term clinical trials are still lacking, and further research is needed.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 315
Author(s):  
Zhenxing Wang ◽  
Zongcai Tu ◽  
Xing Xie ◽  
Hao Cui ◽  
Kin Weng Kong ◽  
...  

This study aims to evaluate the bioactive components, in vitro bioactivities, and in vivo hypoglycemic effect of P. frutescens leaf, which is a traditional medicine-food homology plant. P. frutescens methanol crude extract and its fractions (petroleum ether, chloroform, ethyl acetate, n-butanol fractions, and aqueous phase residue) were prepared by ultrasound-enzyme assisted extraction and liquid–liquid extraction. Among the samples, the ethyl acetate fraction possessed the high total phenolic (440.48 μg GAE/mg DE) and flavonoid content (455.22 μg RE/mg DE), the best antioxidant activity (the DPPH radical, ABTS radical, and superoxide anion scavenging activity, and ferric reducing antioxidant power were 1.71, 1.14, 2.40, 1.29, and 2.4 times higher than that of control Vc, respectively), the most powerful α-glucosidase inhibitory ability with the IC50 value of 190.03 μg/mL which was 2.2-folds higher than control acarbose, the strongest proliferative inhibitory ability against MCF-7 and HepG2 cell with the IC50 values of 37.92 and 13.43 μg/mL, which were considerable with control cisplatin, as well as certain inhibition abilities on acetylcholinesterase and tyrosinase. HPLC analysis showed that the luteolin, rosmarinic acid, rutin, and catechin were the dominant components of the ethyl acetate fraction. Animal experiments further demonstrated that the ethyl acetate fraction could significantly decrease the serum glucose level, food, and water intake of streptozotocin-induced diabetic SD rats, increase the body weight, modulate their serum levels of TC, TG, HDL-C, and LDL-C, improve the histopathology and glycogen accumulation in liver and intestinal tissue. Taken together, P. frutescens leaf exhibits excellent hypoglycemic activity in vitro and in vivo, and could be exploited as a source of natural antidiabetic agent.


Author(s):  
Zhibin Liao ◽  
Hongwei Zhang ◽  
Chen Su ◽  
Furong Liu ◽  
Yachong Liu ◽  
...  

Abstract Background Aberrant expressions of long noncoding RNAs (lncRNAs) have been demonstrated to be related to the progress of HCC. The mechanisms that SNHG14 has participated in the development of HCC are obscure. Methods Quantitative real-time PCR (qRT-PCR) was used to measure the lncRNA, microRNA and mRNA expression level. Cell migration, invasion and proliferation ability were evaluated by transwell and CCK8 assays. The ceRNA regulatory mechanism of SNHG14 was evaluated by RNA immunoprecipitation (RIP) and dual luciferase reporter assay. Tumorigenesis mouse model was used to explore the roles of miR-876-5p in vivo. The protein levels of SSR2 were measured by western blot assay. Results In this study, we demonstrated that SNHG14 was highly expressed in HCC tissues, meanwhile, the elevated expression of SNHG14 predicted poor prognosis in patients with HCC. SNHG14 promoted proliferation and metastasis of HCC cells. We further revealed that SNHG14 functioned as a competing endogenous RNA (ceRNA) for miR-876-5p and that SSR2 was a downstream target of miR-876-5p in HCC. Transwell, CCK8 and animal experiments exhibited miR-876-5p inhibited HCC progression in vitro and in vivo. By conducting rescue experiments, we found the overexpression of SSR2 or knocking down the level of miR-876-5p could reverse the suppressive roles of SNHG14 depletion in HCC. Conclusion SNHG14 promotes HCC progress by acting as a sponge of miR-876-5p to regulate the expression of SSR2 in HCC.


Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 29
Author(s):  
Seung Kyun Yoon ◽  
Jin Ho Yang ◽  
Hyun Tae Lim ◽  
Young-Wook Chang ◽  
Muhammad Ayyoob ◽  
...  

Herein, spinal fixation implants were constructed using degradable polymeric materials such as PGA–PLA block copolymers (poly(glycolic acid-b-lactic acid)). These materials were reinforced by blending with HA-g-PLA (hydroxyapatite-graft-poly lactic acid) and PGA fiber before being tested to confirm its biocompatibility via in vitro (MTT assay) and in vivo animal experiments (i.e., skin sensitization, intradermal intracutaneous reaction, and in vivo degradation tests). Every specimen exhibited suitable biocompatibility and biodegradability for use as resorbable spinal fixation materials.


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