An autophagosome-based therapeutic vaccine for HBV infection: a preclinical evaluation

Effects of Combinatorial Ubiquitinated Protein-Based Nanovaccine and STING Agonist in Mice With Drug-Resistant and Metastatic Breast Cancer

We previously reported that enriched ubiquitinated proteins (UPs) from tumor cells have the potential to be used as immunotherapy vaccine against cancer. Here we enriched UPs from epirubicin (EPB)-induced multi-drug-resistant cancer stem-like breast cancer cell line (4T1/EPB) and tested the efficacy of α-Al₂O₃-UPs-4T1/EPB (short for UPs-4T1/EPB) as therapeutic vaccine alone and in combination with the stimulator of interferon genes (STING) agonist in mice with drug-resistant and metastatic breast cancer. Vaccination with UPs-4T1/EPB exerted profound anti-tumor effects through augmented specific CD8⁺ T cell responses and amplified T cell receptor diversity of tumor-infiltrating lymphocytes (TILs). Importantly, the combination with STING agonist further facilitated the migration of mature CD8α⁺ dendritic cells to the lymph nodes and the infiltration of TILs within tumors, resulting in primary tumor regression and pulmonary metastasis eradication in mice. Moreover, the cured mice were completely resistant against a subsequent rechallenge with the same tumor. Our study indicates that this novel combinatorial immunotherapy with UPs-4T1/EPB vaccine and STING agonist is effective in mice with drug-resistant and metastatic breast cancer.

ASPP2 inhibits hepatitis B virus replication by preventing nucleus translocation of HSF1 and attenuating the transactivation of ATG7

Hepatitis B virus (HBV) is a kind of virus with the capability to induce autophagy, thereby facilitating its replication. Reducing hepatocyte autophagy is proved to be a useful way to inhibit HBV replication. Herein, we reported that p53-binding protein 2 (apoptosis-stimulating protein of p53-2, ASPP2) could attenuate HBV-induced hepatocyte autophagy in a p53-independent manner. Mechanistically, overexpressed ASPP2 binds to HSF1 in cytoplasm of HBV-infected cells, which prevents the translocation of HSF1 to nuclei, thereby inhibiting the transactivation of Atg7. By regulating the transcription of Atg7, ASPP2 reduces hepatocyte autophagy, thereby inhibiting HBV replication. Therefore, ASPP2 is a key regulator of cell autophagy, and overexpression of ASPP2 could be a novel method to inhibit HBV replication in hepatocytes.

Tumor-Derived Autophagosomes (DRibbles) Activate Human B Cells to Induce Efficient Antigen-Specific Human Memory T-Cell Responses

We have reported that tumor-derived autophagosomes (DRibbles) were efficient carriers of tumor antigens and DRibbles antigens could be present by DRibbles-activated B cells to stimulate effect and naïve T cells in mice. However, the effect of DRibbles on human B cells remains unclear. Herein, we found that DRibbles can also efficiently induce proliferation and activation of human B cells and lead to the production of chemokines, cytokines and hematopoietic growth factors. We further demonstrated human B cells can effectively phagocytose DRibbles directly and cross-present DRibbles antigens to stimulate antigen-specific memory T cells. Furthermore, we found that membrane-bound high-mobility group B1 (HMGB1) on DRibbles was crucial for inducing human B cells activation. Therefore, these findings provide further evidence to promote the clinical application of B-DRibbles vaccines.

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.

Anti-Tumor Efficacy of an Adjuvant Built-In Nanovaccine Based on Ubiquitinated Proteins from Tumor Cells

Background and Aim

We have previously identified ubiquitinated proteins (UPs) from tumor cell lysates as a promising vaccine for cancer immunotherapy in different mouse tumor models. In this study, we aimed at developing a highly efficient therapeutic adjuvant built-in nanovaccine (α-Al₂O₃-UPs) by a simple method, in which UPs from tumor cells could be efficiently and conveniently enriched by α-Al₂O₃ nanoparticles covalently coupled with Vx3 proteins (α-Al₂O₃-CONH-Vx3).

Methods

The α-Al₂O₃ nanoparticles were modified with 4-hydroxybenzoic acid followed by coupling with ubiquitin-binding protein Vx3. It was then used to enrich UPs from 4T1 cell lysate. The stability and the efficiency for the UPs enrichment of α-Al₂O₃-CONH-Vx3 were examined. The ability of α-Al₂O₃-UPs to activate DCs was examined in vitro subsequently. The splenocytes from the vaccinated mice were re-stimulated with inactivated tumor cells, and the IFN-γ secretion was detected by ELISA and flow cytometry. Moreover, the therapeutic efficacy of α-Al₂O₃-UPs, alone and in combination with chemotherapy, was examined in 4T1 tumor-bearing mice.

Results

Our results showed that α-Al₂O₃-UPs were successfully synthesized and abundant UPs from tumor cell lysate were enriched by the new method. In vitro study showed that compared to the physical mixture of α-Al₂O₃ nanoparticles and UPs (α-Al₂O₃+UPs), α-Al₂O₃-UPs stimulation resulted in higher upregulations of CD80, CD86, MHC class I, and MHC class II on DCs, indicating the higher ability of DC activation. Moreover, α-Al₂O₃-UPs elicited a more effective immune response in mice, demonstrated by higher IFN-γ secretion than α-Al₂O₃+UPs. Furthermore, α-Al₂O₃-UPs also exhibited a more potent effect on tumor growth inhibition and survival prolongation in 4T1 tumor-bearing mice. Notably, when in combination with low dose chemotherapy, the anti-tumor effect was further enhanced, rather than using α-Al₂O₃-UPs alone.

Conclusion

This study presents an adjuvant built-in nanovaccine generated by a new simple method that can be potentially applied to cancer immunotherapy and lays the experimental foundation for future clinical application.

Vx3-Functionalized Alumina Nanoparticles Assisted Enrichment of Ubiquitinated Proteins from Cancer Cells for Enhanced Cancer Immunotherapy

A simple and effective strategy was developed to enrich ubiquitinated proteins (UPs) from cancer cell lysate using the α-Al₂O₃ nanoparticles covalently linked with ubiquitin binding protein (Vx3) (denoted as α-Al₂O₃-Vx3) via a chemical linker. The functionalized α-Al₂O₃-Vx3 showed long-term stability and high efficiency for the enrichment of UPs from cancer cell lysates. Flow cytometry analysis results indicated dendritic cells (DCs) could more effectively phagocytize the covalently linked α-Al₂O₃-Vx3-UPs than the physical mixture of α-Al₂O₃ and Vx3-UPs (α-Al₂O₃/Vx3-UPs). Laser confocal microscopy images revealed that α-Al₂O₃-Vx3-UPs localized within the autophagosome of DCs, which then cross-presented α-Al₂O₃-Vx3-UPs to CD8⁺ T cells in an autophagosome-related cross-presentation pathway. Furthermore, α-Al₂O₃-Vx3-UPs enhanced more potent antitumor immune response and antitumor efficacy than α-Al₂O₃/cell lysate or α-Al₂O₃/Vx3-UPs. This work highlights the potential of using the Vx3 covalently linked α-Al₂O₃ as a simple and effective platform to enrich UPs from cancer cells for the development of highly efficient therapeutic cancer vaccines.

Autophagy in the "inflammation-carcinogenesis" pathway of liver and HCC immunotherapy

Autophagy plays a dual role in many types of cancer, such as hepatocellular carcinoma (HCC). Autophagy seems to be inhibited and functions as a tumor-suppression mechanism in the "inflammation-carcinogenesis" pathway of the liver, including hepatitis B virus and hepatitis C virus, alcoholic steatohepatitis and non-alcoholic steatohepatitis related HCC. However, in established tumors, autophagy plays a tumor-promoting role. Because of the varied function of autophagy in HCC, we hypothesized p62 as a marker to evaluate the autophagic level. Moreover, autophagy is critical in antigen presentation and homeostasis of immune cells and tumor microenvironment. Understanding the intricate relationships of autophagy, inflammation, and immunity provides us with new insights into HCC immunotherapy.

In Silico Analysis of Epitope-Based Vaccine Candidates against Hepatitis B Virus Polymerase Protein

Hepatitis B virus (HBV) infection has persisted as a major public health problem due to the lack of an effective treatment for those chronically infected. Therapeutic vaccination holds promise, and targeting HBV polymerase is pivotal for viral eradication. In this research, a computational approach was employed to predict suitable HBV polymerase targeting multi-peptides for vaccine candidate selection. We then performed in-depth computational analysis to evaluate the predicted epitopes’ immunogenicity, conservation, population coverage, and toxicity. Lastly, molecular docking and MHC-peptide complex stabilization assay were utilized to determine the binding energy and affinity of epitopes to the HLA-A0201 molecule. Criteria-based analysis provided four predicted epitopes, RVTGGVFLV, VSIPWTHKV, YMDDVVLGA and HLYSHPIIL. Assay results indicated the lowest binding energy and high affinity to the HLA-A0201 molecule for epitopes VSIPWTHKV and YMDDVVLGA and epitopes RVTGGVFLV and VSIPWTHKV, respectively. Regions 307 to 320 and 377 to 387 were considered to have the highest probability to be involved in B cell epitopes. The T cell and B cell epitopes identified in this study are promising targets for an epitope-focused, peptide-based HBV vaccine, and provide insight into HBV-induced immune response.

Hepatitis B virus therapy: What’s the future holding for us?

Hepatitis B is one of the leading causes of liver cancer worldwide and unfortunately the number of people affected with hepatitis B virus (HBV) infection is still on the rise. Although the HBV has been known to cause fatal illness since decades but the population effected by this lethal virus have still only a few options for its management. The major treatment strategies include interferons and nucleos(t)ide analogues. These agents have so far produced unsatisfactory results in terms of complete virus eradication. Interferons cannot be used for long term therapy because of their potential side effects. Prolong treatment with nucleos(t)ide analogues has also been reported to cause serious side effects besides the increasing resistance by the virus. The need for new innovative solutions for treatment of HBV has been realized by global research institutes and pharmaceutical industry. Present review focuses in detail on the new ideas that are being transformed into therapeutic tools for use as future therapies in HBV infection. Modern drug designing and screening methods have made the drug discovery process shorter and more reliable. HBV therapeutics will take a new turn in coming years owing to these intelligent drug designing and screening methods. Future therapy of HBV is aiming to include the use of vaccines (both prophylactic and therapeutic), immunomodulators such as antibodies, non-nucleoside antivirals such as RNAi and inhibitors of viral life cycle.