Inhibition of dendritic cell maturation and function is independent of heme oxygenase 1 but requires the activation of STAT3

The induction of heme oxygenase 1 (HO-1) by a single treatment with cobalt protoporphyrin (CoPPIX) protects against inflammatory liver failure and ischemia reperfusion injury after allotransplantation. In this context, the HO-1-mediated inhibition of donor-derived dendritic cell maturation and migration is discussed as one of the key events of graft protection. To investigate the poorly understood mechanism of CoPPIX-induced HO-1 activity in more detail, we performed gene expression analysis in murine liver, revealing the up-regulation of STAT3 after CoPPIX treatment. By using wild-type and HO-1-deficient dendritic cells we demonstrated that LPS-induced maturation is dependent on STAT3 phosphorylation and independent of HO-1 activity. In summary, our observations revise our understanding of the anti-inflammatory properties of HO-1 and highlight the immunomodulatory capacity of STAT3, which might be of further interest for targeting undesired immune responses, including ischemia reperfusion injury.     

Amplifying the fluorescence of bilirubin enables the real-time detection of heme oxygenase activity

Heme oxygenases (HO) are the rate-limiting enzymes in the degradation of heme to equimolar amounts of antioxidant bile pigments, the signaling molecule carbon monoxide, and ferric iron. The inducible form HO-1 confers protection on cells and tissues that mediates beneficial effects in many diseases. Consequently, measurement of the enzymatic activity is vital in the investigation of the regulatory role of HO. Here we report that the fluorescence characteristics of bilirubin in complex with serum albumin can be used for the real-time detection of HO activity in enzymatic kinetics measurements. We characterized the enzymatic activity of a truncated human HO-1 and measured the HO activity for various cell types and organs, in either the basal naive or the HO-1-induced state. The bilirubin-dependent increase in fluorescence over time monitored by this assay facilitates a very fast, sensitive, and reliable measurement of HO activity. Our approach offers the basis for a highly sensitive high-throughput screening, which provides, inter alia, the opportunity to discover new therapeutic HO-1-inducing agents.     

Attachment of a Frog Skin-Derived Peptide to Functionalized Cerium Oxide Nanoparticles

Peptide Brevinin-2R (B2R) has derived from frog skin secretions and possesses cytotoxic effects on cancer cells. Beside, cerium oxide nanoparticle (CNP) has antioxidant properties and could be used in anticancer studies. The purpose of this study is to investigate antioxidant and cytotoxicity of cerium oxide nanoparticle conjugated with B2R. First, cerium oxide nanoparticles were amine functionalized and peptide attached to it through establishment of peptide bond. Then, (1,1-diphenyl-2-picrylhydrazyl) DPPH and 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging activities of CNP-B2R were determined. MTT assay were used in order to compare cytotoxicity of CNP- B2R on two different cell lines. HFLF-pI5 cell and A549 cell lines were selected as representative of normal and cancer cells, respectively. Also, the cytotoxic effects of CNP, B2R and CNP-B2R were investigated on A549 cell line. Results of antioxidant evaluations showed that the antioxidant activity of CNP-Peptide increased at higher concentration of CNP-B2R with IC₅₀ of 0.2 and 0.54 (mg/mL) for DPPH and ABTS assays, respectively. The results of cytotoxicity effects showed that CNP-B2R was more potent in killing tumor cell line in comparison with normal cell line. Cytotoxicity of CNP, B2R and CNP-B2R demonstrated that CNP-B2R and B2R had the lower cell viability effects compared to CNP. Our findings showed cytotoxicity of CNP-B2R against cancer cell lines in comparison with normal cells indicating the potential anticancer properties of CNP-B2R.     

Immunoliposomes bearing lymphocyte activation gene 3 fusion protein and P5 peptide: A novel vaccine for breast cancer

LAG3-Ig as an immune adjuvant has elicited potent anti-tumor immune responses in several preclinical and clinical studies, but the full potential immunostimulatory of LAG3-Ig has yet to be achieved. We hypothesized that by anchoring LAG3-Ig to the surface of liposomes, the adjuvant activity of LAG3-Ig could be improved. We also investigated the immunotherapy by co-delivery of liposome-coupled LAG3-Ig and P5 tumor antigen in mice model of TUBO breast cancer. We prepared and characterized novel PEGylated liposomes bearing surface conjugated LAG3-Ig and P5. Consistent with our hypothesis, liposomes-conjugated LAG3-Ig via multivalent binding to MHC class II molecules exerted immunostimulatory of LAG3-Ig and markedly induced maturation of dendritic cells more efficiently than free LAG3-Ig. LAG3-Ig-P5-immunoliposomes effectively elicited protective anti-tumor responses more than locally injected soluble LAG3-Ig + P5. The higher percentage of CD4⁺ and CD8⁺ T cells in the spleen and more rapid and pronounced infiltration of these effector cells into the site of the tumor were seen following immunoliposome therapy. Finally, anti-tumor immunity induced by LAG3-Ig-P5-immunoliposomes translated into the more tumor regression and prolonged survival of treated mice, compared to soluble immunotherapy. Taken together, our findings suggest that LAG3-Ig-P5-immunoliposomes can be considered as a valuable candidate for developing a liposome-based therapeutic cancer vaccine in treating HER2/ neu⁺ breast cancer patients.     

Efficacy Comparison of TAT Peptide-Functionalized PEGylated Liposomal Doxorubicin in C26 and B16F0 Tumor Mice Models

International Journal of Peptide Research and Therapeutics - This study aimed to evaluate the antitumor activity of PEGylated liposomal doxorubicin (Dox) functionalized with TAT peptide through...     

Anti-epithelial cell adhesion molecule RNA aptamer-conjugated liposomal doxorubicin as an efficient targeted therapy in mice bearing colon carcinoma tumor model

To overcome the lack of selectivity and nonspecific biodistribution of drugs in the body, targeted delivery of chemotherapeutic agents with aptamers is a very effective method. In this strategy, aptamers could be specifically identified and attach to targeted molecules on the cancerous cells and deliver the chemotherapeutic agents to desired tissue with minimal or no damage to the normal cells. In this study, we designed anti-epithelial cell adhesion molecule (EpCAM) RNA aptamer conjugated PEGylated liposomal doxorubicin (ER-lip) to investigate its in vitro and in vivo anticancer abilities. Data showed that EpCAM aptamer was able to enhance cell uptake and cytotoxic effects of Dox in C26 cell line. The biodistribution study indicated that ER-lip enhanced the tumor accumulation of Dox compared to Caelyx. Also, double staining of isolated tumor cells with anti-CD44-PE-cy5 and anti-EpCAM Cy-7 antibodies indicated that tumor cells expressed a high level of EpCAM⁺ CD44⁺ cells (p ≤ .001) compared to cultured C26 cell line. in vivo results showed that ER-lip promoted survival and reduced tumor growth rate in animal model compared to Caelyx. In conclusion, these results suggested that the ER-lip could be served as promising formulation for the treatment of cancers with the high expression of EpCAM.