Yahong Wu

LncSox4 promotes the self-renewal of liver tumour-initiating cells through Stat3-mediated Sox4 expression

Liver cancer has a tendency to develop asymptomatically in patients, so most patients are diagnosed at a later stage. Accumulating evidence implicates that liver tumour-initiating cells (TICs) as being responsible for liver cancer initiation and recurrence. However, the molecular mechanism of liver TIC self-renewal is poorly understood. Here we discover that a long noncoding RNA (lncRNA) termed LncSox4 is highly expressed in hepatocellular carcinoma (HCC) tissues and in liver TICs. We find that LncSox4 is required for liver TIC self-renewal and tumour initiation. LncSox4 interacts with and recruits Stat3 to the Sox4 promoter to initiate the expression of Sox4, which is highly expressed in liver TICs and required for liver TIC self-renewal. The expression level of Sox4 correlates with HCC development, clinical severity and prognosis of patients. Altogether, we find that LncSox4 is highly expressed in liver TICs and is required for their self-renewal.

Identification of a novel cytotoxic T lymphocyte epitope from CFP21, a secreted protein of Mycobacterium tuberculosis.

CFP21 is a major secreted protein of Mycobacterium tuberculosis (Mtb) which is considered as a promising antigen for immunotherapy. To identify CFP21-derived HLA-A*0201 restricted epitopes, a series of native peptides and their analogues were predicted with prediction programs and synthesized. The native peptide, p134 (AVADHVAAV), and its analogues, p134-1Y2L and p134-1Y2L9L, showed potent binding affinity and stability to HLA-A*0201 molecule. In ELISPOT assay, the cytotoxic T lymphocytes (CTLs) induced by these peptides could release IFN-γ. In cytotoxicity assay, the CTLs induced by p134 and p134-1Y2L9L could specifically lyse peptide-loaded T2 cells. In these two assays, the native peptide, p134, showed the most potent activity. Our results indicated that p134 could be a novel epitope which could serve as a good candidate to develop peptide vaccines against M. tuberculosis.

A novel peptide targeting Clec9a on dendritic cell for cancer immunotherapy

Dendritic cells (DCs) are professional antigen-presenting cells with antigen recognition molecules on the surface. Clec9a is selectively expressed on mouse CD8a+ DCs and CD103+ DCs subsets, which are functionally similar to human BDCA3+ DCs. It is reported that Clec9a is responsible for the antigen cross-presentation of these DC subsets. In the present study, by using phage display technique, we discovered a novel peptide WH, which can selectively bind to mouse Flt3L induced Clec9a+ DCs or Clec9a over-expressed HEK-293T cells. Furthermore, by using computer-aided docking model and mutation assay, we observed that Asp248 and Trp250 are two key residues for Clec9a to bind with peptide WH. When coupled with OVA257-264 epitope, peptide WH can significantly enhance the ability of Clec9a+ DCs to activate OVA-specific CD8+ T cells, which elicit strong ability to secret IFN-γ, express perforin and granzyme B mRNA. In B16-OVA lung metastasis mouse model, WH-OVA257-264 fusion peptide can also enhance the activation of CD8+ T cells and decrease the lung metastasis loci. All these results suggested that peptide WH could be considered as an antigen delivery carrier targeting Clec9a+ DCs for cancer immunotherapy.

Identification of a Novel CD8+ T Cell Epitope Derived from Cancer-Testis Antigen MAGE-4 in Oesophageal Carcinoma

MAGE‐4 is considered as an attractive cancer‐testis (CT) antigen for tumour immunotherapy, and it is overexpressed in oesophageal carcinoma (EC). To identify MAGE‐4‐derived HLA‐A2 restricted epitopes, native peptides and their analogues were predicted with prediction programs. The native peptide, p286 (KVLEHVVRV), and its analogues, p286‐1Y2L and p286‐1Y2L9L, showed potent binding affinity and stability towards HLA‐A*0201 molecule. Cytotoxic T lymphocytes (CTLs) induced by p286‐1Y2L9L could release IFN‐γ in ELISPOT assay. In cytotoxicity assay, p286‐1Y2L9L showed the capability to induce specific CTLs which could lyse the target cancer cells from both PBMCs of healthy donors and HLA‐A2.1/Kb transgenic mice. Our results indicated that the peptide p286‐1Y2L9L could serve as a novel candidate epitope to develop peptide vaccines against oesophageal carcinoma.

A Novel Cytotoxic T lymphocyte Epitope Analogue with Enhanced Activity Derived From Cyclooxygenase-2

Cyclooxygenase‐2 is a promising target for cancer immunotherapy. Here, we designed the analogues p321‐9L and p321‐1Y9L (YLIGETIKL) from cyclooxygenase‐2‐derived native peptide p321. Then, we tested the binding affinity and stability of the analogues and their ability to elicit specific immune response both in vitro (from PBMCs of HLA‐A*02+ healthy donors) and in vivo (from HLA‐A2.1/Kb transgenic mice). Our results indicated that the activity of cytotoxic T lymphocytes induced by p321‐9L and p321‐1Y9L was more potent than that of p321. In conclusion, the epitope analogue, especially p321‐1Y9L, may be a good candidate which could be used to the immunotherapy of patients with tumours expressing cyclooxygenase‐2.

Novel epitopes identified from efflux pumps of Mycobacterium tuberculosis could induce cytotoxic T lymphocyte response

Overcoming drug-resistance is one of the major challenges to control tuberculosis (TB). The up-regulation of efflux pumps is one common mechanism that leads to drug-resistance. Therefore, immunotherapy targeting these efflux pump antigens could be promising strategy to be combined with current chemotherapy. Considering that CD8+ cytotoxic T lymphocytes (CTLs) induced by antigenic peptides (epitopes) could elicit HLA-restricted anti-TB immune response, efflux pumps from classical ABC family (Mycobacterium tuberculosis, Mtb) were chosen as target antigens to identify CTL epitopes. HLA-A2 restricted candidate peptides from Rv2937, Rv2686c and Rv2687c of Mycobacterium tuberculosis were predicted, synthesized and tested. Five peptides could induce IFN-γ release and cytotoxic activity in PBMCs from HLA-A2+ PPD+ donors. Results from HLA-A2/Kb transgenic mice immunization assay suggested that four peptides Rv2937-p168, Rv2937-p266, Rv2686c-p151, and Rv2686c-p181 could induce significant CTL response in vivo. These results suggested that these novel epitopes could be used as immunotherapy candidates to TB drug-resistance.

A Novel Recombinant Multi-Epitope Vaccine Could Induce Specific Cytotoxic T Lymphocyte Response In Vitro and In Vivo

BACKGROUND Malignant tumor is still one of the important diseases worldwide, cytotoxic CD8+ T lymphocytes (CTLs) play an important role in killing tumor cells. OBJECTIVE To enhance the immune response of our previously identified HLA-A2-restricted CTL epitopes, we designed a multiepitope YL66. METHOD The fusion protein GST-YL66 and DNA vaccine pcDNA3.1(+)-YL66 were used to induce CTLs from human peripheral blood mononuclear cells (PBMCs) of HLA-A*02+ healthy donors and and in HLA-A2.1/Kb transgenic(Tg) mice. and the activity of induced CTLs were tested by IFN-γ relesde ELISPOT assay and LDH cytotoxicity assay. RESULTS GST-YL66 induced CTL could lysis tumor cells and release IFN-γ both in vitro and in vivo, and pcDNA3.1(+)-YL66 could also induce significant CTL response in vivo. CONCLUSION The designed fusion multiepitope YL66 could be used as a vaccine against patients with tumors expressing COX-2 and/or MAGE-4.