Bis-2'-F-cGSASMP isomers encapsulated in cytidinyl/cationic lipids act as potent in situ autologous tumor vaccines.

Cancer immunotherapy has greatly improved the prognosis of tumor-bearing patients. Nevertheless, cancer patients exhibit low response rates to current immunotherapy drugs, such as PD1 and PDL1 antibodies. Cyclic dinucleotide analogs are a promising class of immunotherapeutic agents. In this study, in situ autologous tumor vaccines, composed of bis-2'-F-cGSASMP phosphonothioate isomers (FGA-di-pS-2 or FGA-di-pS-4) and cytidinyl/cationic lipids (Mix), were constructed. Intravenous and intratumoral injection of FGA-di-pS-2/Mix or FGA-di-pS-4/Mix enhanced the immunogenic cell death of tumor cells in vivo, leading to the exposure and presentation of whole tumor antigens, inhibiting tumor growth in both LLC and EO771 tumor in situ murine models and increasing their survival rates to 50% and 23%, respectively. Furthermore, the tumor-bearing mice after treatment showed potent immune memory efficacy and exhibited 100% protection against tumor rechallenge. Intravenous administration of FGA-di-pS-2/Mix potently promoted DC maturation, M1 macrophage polarization and CD8+ T cell activation and decreased the proportion of Treg cells in the tumor microenvironment. Notably, two doses of ICD-debris (generated by FGA-di-pS-2 or 4/Mix-treated LLC cells) protected 100% of mice from tumor growth. These tumor vaccines showed promising results and may serve as personalized cancer vaccinations in the future.

Cyclic diguanylate analogues: Facile synthesis, STING binding mode and anti-tumor immunity delivered by cytidinyl/cationic lipid.

Herein 2-cyanoethoxy-N,N,N',N'-tetraisopropyl-phosphorodiamidite(10, PIII, 3.5 eq.) could synergistically react with 3',5'-dihydroxyl groups in a dinucleotide(PV) at the cyclization step for the synthesis of cyclic dinucleotides (CDNs) (c-di-GMP, cGAMP etc.) and their phosphorothioated analogues. A dynamic PIII-PV coordination mechanism has been proposed for the cyclization procedure which is confirmed by the variant 31P NMR data and molecular simulation. Among the mono-phosphorothioated CDNs, two stereoisomers showed different capacity for STING activation and the reason was predicted by molecular modeling. While compound 12b1 showed most potent ability to elicit cytokines (IFNß, IL-6, Cxcl9 and Cxcl10) induction compared to another stereoisomer. Also, 12b1 significantly inhibited the tumor growth in the EO771 model with both 0.1 µg (i.t.) and 2 µg (i.v.) administration through the aid of a Mix delivery system developed by our group, and achieved a 31% long-term survival rate of tumor-bearing mice. 12b1/Mix significantly improved the percentage of CD8+ or CD4+ effector memory T (Tem, CD44highCD62Llow) cells and CD8+ central memory T (Tcm, CD44highCD62Lhigh) cells in the blood of EO771 mice, inducing the immune memory against EO771 tumor cells. Relatively lower dose regimens of 12b1(0.1 µg)/Mix displayed better tumor suppression by more potent STING pathway activation and higher levels of cytokines induction in the tumor.

Novel formulation of c-di-GMP with cytidinyl/cationic lipid reverses T cell exhaustion and activates stronger anti-tumor immunity.

Rationale: Cyclic dinucleotides (cDNs) are a promising class of immunotherapeutic agent targeting stimulator of interferon genes (STING). However, enzymatic instability and transmembrane barriers limit the extensive clinical application of cDNs. Thus, a novel delivery system, composed of a neutral cytidinyl lipid DNCA and a cationic lipid CLD (Mix) that interacts with cDNs via H-bonding, pi-stacking and electrostatic interaction, is developed and optimized to overcome the above issues. Methods: The optimal composition of Mix for cDNs encapsulation was explored with RAW-Lucia ISG cells. The physicochemical properties of resulted nanoparticles were characterized. To validate the anti-tumor immunity of cDNs/Mix both in vitro and in vivo, immunogenic cell death (ICD) related markers and tumor inhibition efficacy were evaluated in cancer cells and tumor models, respectively. The mechanism by which cdG/Mix exerted the antitumor effects was explored by flow cytometric analysis and in vivo depletion. Results: Based on our developed and optimized delivery system, neutral cytidinyl lipid DNCA/cationic lipid CLD (Mix), cdG (500 nM in vitro, 1-10 µg in vivo)/Mix not only more potently stimulated production of IFNß and related cytokines including CXCL9 and CXCL10, promoted ICD, led to NK and CD8+ T cell activation, inhibited tumor growth in both EO771 and B16F10 models and increased their survival rate (~43%), but also obviously reversed the T cell exhaustion (Tex) in tumor, meanwhile down regulated the mRNA expression of Tox and Nr4a, which are key regulators of Tex. Conclusion: cdG/Mix triggered ICD in various cancer cells and reversed the Tex systemically in tumor-burden mice, which would be a promising alternative strategy for cancer immunotherapy.

Pd based in situ AOPs with heterogeneous catalyst of FeMgAl layered double hydrotalcite for the degradation of bisphenol A and landfill leachate through multiple pathways.

In situ degradation of organic contaminants by Pd and electro-generated H2 and O2 overcomes the drawbacks to traditional Fenton process, and conducting heterogeneous catalyst of FeMgAl layered double hydrotalcite (LDH) further improved the efficiency and stability. Using bisphenol A (BPA) as the model contaminants, 90% removal can be achieved with 1200 mg/L Pd/Al2O3 and FeMgAl-2. The reusability was satisfying due to the very limited leaching of Fe ions at 0.1 ppm level. FeMgAl also amplified the window of pH for Pd-catalyzed in situ advanced oxidation processes (AOPs) from 3 by homogenous Fe(II) to 3-7 by FeMgAl LDH. The COD of landfill leachate effluent of the MBR system removed by about 52.3% by this system by the initial pH was 5. Characterizations revealed the distinguishing features associated with LDH structure such as large surface area, good stability, basic character, and strong linage among active sites were accounted for the remarkable performances over a wide pH window. Five reactive intermediates were observed and multiple degradation pathways were proposed in Pd-catalyzed in situ AOP for the first time. Interestingly, because of the unique role of Pd catalyst, these degradation pathways were clearly distinguished from traditional Fenton or Fenton-like AOPs and may provide a new approach of in situ heterogeneous AOPs for refractory contaminants in future.

Immobilization of Cd in landfill-leachate-contaminated soil with cow manure compost as soil conditioners: A laboratory study.

Introducing cow manure compost as an amendment in landfill-leachate-contaminated soils is proved to be an effective technique for the immobilization of Cd in this study. Landfill-leachate-contaminated soil was collected from an unlined landfill in China and amended with a different blending quantity of cow manure compost (0, 12, 24, 36, and 48 g per 200 g soil), which was made by mixing cow manure and chaff at a ratio of 1/1 and maturing for 6 months. pH values of five different blending quantity mixtures increased by 0.2-0.4, and the organic matter levels increased by 2.5-7%, during a remediation period of 5 weeks. Four fractions of Cd named exchangeable Cd, reducible Cd, oxidizable Cd, and residual Cd in soil were respectively analyzed by a sequential extraction procedure. Introducing the cow manure compost application resulted in more than 40% lower exchangeable Cd but a higher concentration of oxidizable Cd in soils, and mass balance results showed nearly no Cd absorption by applied material, indicating that transformation of exchangeable Cd into oxidization forms was the main mechanism of Cd immobilization when cow manure compost was used as an amendment. The Pearson correlation showed that increasing of pH values significantly improved the efficiency of Cd immobilization, with a correlation coefficiency of 0.940 (p < 0.05). This is the first attempt at heavy metal immobilization in landfill-leachate-contaminated soil by cow manure compost, and findings of this work can be integrated to guide the application. IMPLICATIONS: Addition of cow manure compost (CMC) was effective in reducing exchangeable Cd in landfill-leachate-contaminated soils (LLCS). The immobilization effect of Cd was mainly assigned to the redistribution of labile soil Cd. Organic matter (OM) and pH value increased with CMC application. The pH values were more sensitive to Cd immobilization efficiency. It was proved that CMC can be safely and effectively used for the restoration of LLCS.