An engineered novel lentivector specifically transducing dendritic cells and eliciting robust HBV-specific CTL response by upregulating autophagy in T cells

Avasimibe can cooperate with a DC-targeting and integration-deficient lentivector to induce stronger HBV specific T cytotoxic response by regulating cholesterol metabolism

We have reported a lentivector which could effectively induce HBV-specific cytotoxic T lymphocytes (CTLs). Avasimibe is an inhibitor of acetyl-CoA acetyltransferase-1 (ACAT1), and has been shown to enhance T lymphocyte cytotoxicity on tumor cells. However, the role of avasimibe in lentivector-induced HBV-specific T cytotoxic response remains unknown. Based on previous study, we constructed an integration-deficient lentivector LVDC-ID-HBV (harboring HBcAg expression), and the in vitro experiments showed that the combination of avasimibe exhibited better efficacy in inducing HBV-specific CTL responses including cell proliferation, production of cytokines, as well as CTL killing activities. Mechanism experiments showed that increasing cell membrane cholesterol levels by MβCD-coated cholesterol or ACAT1 inhibition efficiently promoted TCR clustering, signaling transduction and immunological synapse formation, thereby mediating augmented CTL responses. Nevertheless, the depletion of plasma membrane cholesterol with MβCD led to obviously decreased CTL responses. The avasimibe-mediated strengthened immune effects were also determined in animal experiments and the results were in agreement with those from the in vitro research. In particular, the in vivo CTL killing activities were identified by the CFSE or BV-labeled splenocyte lysis assay. Moreover, the experiments in HBV transgenic mice showed that the LVDC-ID-HBV plus avasimibe group demonstrated the lowest serum HBsAg and HBV DNA levels, as well as the lowest expression of HBsAg and HBcAg in liver tissues. We concluded that the HBV-specific CTL immune responses could be potentiated by avasimibe through regulating plasma membrane cholesterol levels. Avasimibe may be a potential adjuvant for lentivector vaccine against HBV infection.

A pan-cancer analysis for the oncogenic role of cyclin-dependent kinase inhibitor 1B in human cancers

BACKGROUND

Human health and life are threatened by cancer with high morbidity and mortality worldwide. In many experiments, CDKN1B level is associated with cancer risk, Nevertheless, no pan-cancer analysis has been conducted on CDKN1B in human cancers.

METHODS

With the help of bioinformatics, a pan-cancer analysis was conducted on the expression levels of CDKN1B in cancer tissues and adjacent tissues from the TCGA, CPTAC and GEO databases. The CDKN1B expression levels in tumor patients was further validated using immunohistochemistry (IHC) and quantitative real-time PCR.

RESULTS

In the study, we first investigated the cancer-related roles of CDKN1B's in 40 tumors with malignancy. The CDKN1B gene encodes the p27^Kip1 protein, which can block the production cyclin-dependent kinase (CDK), which is obviously related to the function and survival of cancer cells and alters the prognosis of cancer patients. Furthermore, CDKN1B function requires both protein processing and RNA metabolism. Additionally, the elevated expression of the CDKN1B gene and protein was validated in several cancer tissues from the patients.

CONCLUSIONS

These results showed that the levels of CDKN1B were considerably different in a number of cancer tissues, offering a potential future target for cancer therapy.

Combined therapy with methotrexate nanoconjugate and dendritic cells with downregulated IL-10R expression modulates the tumor microenvironment and enhances the systemic anti-tumor immune response in MC38 murine colon carcinoma

Background

Understanding the negative impact of the tumor microenvironment on the creation of an effective immune response has contributed to the development of new therapeutic anti-cancer strategies. One such solution is combined therapy consisting of chemotherapeutic administration followed by dendritic cell (DC)-based vaccines. The use of cytostatic leads to the elimination of cancer cells, but can also modulate the tumor milieu. Moreover, great efforts are being made to increase the therapeutic outcome of immunotherapy, e.g. by enhancing the ability of DCs to generate an efficient immune response, even in the presence of immunosuppressive cytokines such as IL-10. The study aimed to determine the effectiveness of combined therapy with chemotherapeutic with immunomodulatory potential - HES-MTX nanoconjugate (composed of methotrexate (MTX) and hydroxyethyl starch (HES)) and DCs with downregulated expression of IL-10 receptor stimulated with tumor antigens (DC/shIL-10R/TAg) applied in MC38 murine colon carcinoma model.

Methods

With the use of lentiviral vectors the DCs with decreased expression of IL-10R were obtained and characterized. During in vivo studies MC38-tumor bearing mice received MTX or HES-MTX nanoconjugate as a sole treatment or combined with DC-based immunotherapy containing unmodified DCs or DCs transduced with shRNA against IL-10R (or control shRNA sequence). Tumor volume was monitored during the experiment. One week after the last injection of DC-based vaccines, tumor nodules and spleens were dissected for ex vivo analysis. The changes in the local and systemic anti-tumor immune response were estimated with the use of flow cytometry and ELISA methods.

Results and conclusions

In vitro studies showed that the downregulation of IL-10R expression in DCs enhances their ability to activate the specific anti-tumor immune response. The use of HES-MTX nanoconjugate and DC/shIL-10R/TAg in the therapy of MC38-tumor bearing mice resulted in the greatest tumor growth inhibition. At the local anti-tumor immune response level a decrease in the infiltration of cells with suppressor activity and an increase in the influx of effector cells into MC38 tumor tissue was observed. These changes were crucial to enhance the effective specific immune response at the systemic level, which was revealed in the greatest cytotoxic activity of spleen cells against MC38 cells.

Interplay between Cellular Autophagy and Hepatitis B Virus Replication: A Systematic Review

Autophagy, a conserved process in which cells break down and destroy old, damaged, or abnormal proteins and other substances in the cytoplasm through lysosomal degradation, occurs via autophagosome formation and aids in the maintenance of intracellular homeostasis. Autophagy is closely associated with hepatitis B virus (HBV) replication and assembly. Currently, HBV infection is still one of the most serious public health issues worldwide. The unavailability of satisfactory therapeutic strategies for chronic HBV infection indicates an urgent need to elucidate the mechanisms underlying the pathogenesis of HBV infection. Increasing evidence has shown that HBV not only possesses the ability to induce incomplete autophagy but also evades autophagic degradation, indicating that HBV utilizes or hijacks the autophagy machinery for its own replication. Therefore, autophagy might be a crucial target pathway for controlling HBV infection. The definite molecular mechanisms underlying the association between cellular autophagy and HBV replication require further clarification. In this review, we have summarized and discussed the latest findings on the interplay between autophagy and HBV replication.