Glucocorticoids Impair the 7α-Hydroxycholesterol-Enhanced Innate Immune Response

Glucocorticoids suppress the vascular inflammation that occurs under hypercholesterolemia, as demonstrated in an animal model fed a high-cholesterol diet. However, the molecular mechanisms underlying these beneficial effects remain poorly understood. Because cholesterol is oxidized to form cholesterol oxides (oxysterols) that are capable of inducing inflammation, we investigated whether glucocorticoids affect the immune responses evoked by 7α-hydroxycholesterol (7αOHChol). The treatment of human THP-1 monocytic cells with dexamethasone (Dex) and prednisolone (Pdn) downregulated the expression of pattern recognition receptors (PRRs), such as TLR6 and CD14, and diminished 7αOHCholenhanced response to FSL-1, a TLR2/6 ligand, and lipopolysaccharide, which interacts with CD14 to initiate immune responses, as determined by the reduced secretion of IL-23 and CCL2, respectively. Glucocorticoids weakened the 7αOHChol-induced production of CCL2 and CCR5 ligands, which was accompanied by decreased migration of monocytic cells and CCR5-expressing Jurkat T cells. Treatment with Dex or Pdn also reduced the phosphorylation of the Akt-1 Src, ERK1/2, and p65 subunits. These results indicate that both Dex and Pdn impair the expression of PRRs and their downstream products, chemokine production, and phosphorylation of signaling molecules. Collectively, glucocorticoids suppress the innate immune response and activation of monocytic cells to an inflammatory phenotype enhanced or induced by 7αOHChol, which may contribute to the anti-inflammatory effects in hypercholesterolemic conditions.

Enhanced Oncolytic Effect and Anti-Tumor Effect of Replication Competent Adenovirus with Double Mutation in E1A & E1B Regions

Gene-modified replication-competent adenoviruses (Ads) are emerging as a promising new modality for the treatment of cancer. We have previously shown that E1B 19kDa and E1B 55kDa gene deleted Ad (Ad-deltaE1B19/55) exhibits improved tumor-specific replication and cell lysis, leading to potent anti-tumor effect. As an additional effort to increase cancer cell-selectivity of replicating adenovirus, we have first generated eleven E1A-mutant Ads (Ad-mt#1~#11) with deletion or substitution in retinoblastoma (Rb) binding sites of E1A. Of these viruses, Ad-mt#7 demonstrated significantly improved cytopathic effect (CPE) and viral replication in a cancer cell-specific manner. To further increase the cancer cell-specific killing effect of Ad-mt#7, both E1B 19kDa and E1B 55kDa genes were deleted, resulting in an Ad-deltaE1Bmt7. As assessed using CPE assay, MTT assay, and immunoblot analysis for Ad fiber expression, Ad-deltaE1Bmt7 exerted markedly enhanced cancer cell-specific killing effect as well as viral replication in comparison to either Ad-mt#7 or Ad-deltaE1B19/55. Furthermore, the growth of established human cervical carcinoma in nude mice was significantly suppressed by intratumoral injection of Ad-deltaE1Bmt7. In summary, we have developed an oncolytic adenovirus with significantly improved therapeutic profiles for cancer treatment.

Tumor - specific Virus Replication and Cytotoxicity of E1B 55 kD - deleted Adenovirus / 대한암학회지

PURPOSE: To overcome the limitations of cancer gene therapy using replication-incom- petent adenovirus, we generated E1B 55 kD-deleted adenovirus (YKL-1) by polymerase chain reaction (PCR) and homologous recombination. We then investigated tumor-specific virus replication and cytotoxicity of YKL-1 in vitro and in vivo. MATERIALS AND METHODS: YKL-1 was constructed by reintroducting E1A and E1B 19 kD into pTG-CMV El/E3-deficient adenoviral vector and inducing homologous recombination in E. coli. The recombinant vector pYKL-1 was transfected into 293 cells to generate YKL-1. The properties of newly constructed YKL-1 was defined by PCR and immuno- blotting analysis. Virus replication was examined by infecting human normal and cancer cells on 6-wells at multiplicity of infection (MOI) of 10 for 3 days. Virus was then recovered and titered. Cytopathic effect was analyzed by infecting human normal and cancer cells on 24-wells at MOIs of 10, 1 or 0.1 for 7 to 10 days and staining them with crystal violet solution. Inhibition of tumor growth was examined in human cancer cell xenografts in nu/nu mice by intratumoral injection of YKL-l. RESULTS: PCR and immunoblotting analysis confirmed that YKL-1 contained E1A and E1B 19 kD but not E1B 55 kD. In human normal cells, virus replication and subsequent cytopathic effect of E1B 55 kD-deleted adenovirus YKL-1 was markedly attenuated by larger than 2 to 3 log in magnitude, compared to that of wild-type ad-XJ. In contrast, YKL-1 was capable of replicating and inducing cytotoxicity i.n most human cancer cells. C33A and Hep3B containing p53 mutation were much more sensitive, whereas HeLa and H460 with wild type p53 were relatively resistant to YKL-1. Finally, the tumor growth was dramatically retarded by intratumoral injection of YKL-1 in C33A cervical cancer xenograft and the histology showed significant necrosis by intratumoral injection of YKL-1. CONCLUSION: The results here demonstrated the ability of preferential virus replication and cytotoxicity of ElB 55 kD-deleted adenovirus YKL-1 in human cancer cells. Therefore, these indicated a promising potential of YKL-1 as an antitumoral virus agent and a selective replication-competent virus vector.