Phenotypic and functional characterization of cytotoxic T lymphocytes by flow cytometry

Regulation of NLRP3 inflammasome and Caspase-3/4/11 by 2',4'-dihydroxychalcone contributes to anti-colorectal cancer

BACKGROUND

Chronic inflammation is closely related to the occurrence and progression of many cancers, especially colorectal cancer (CRC), which can be triggered by repeated and sustained induction of colitis in mice. CRC is a typical type of cancer that can be caused by inflammation and NLRP3 inflammasome dysregulation plays a certain role in the pathogenesis of CRC.

PURPOSE

As an edible Chinese medicine, Abrus cantoniensis Hance (ACH) has both anti-inflammatory and anti-tumor activities. However, most research has focused on inflammation-related diseases, and less research has been done on its active ingredients and targets and its application in CRC. Here, this study deeply explored the target of 2',4'-DHC and its pharmacological mechanism in anti-colon cancer, and provided a new strategy for its drug development and treatment of colon cancer.

METHODS

The cytotoxicity of ACH's active ingredient in HT29 and CT26 cells was measured by CCK-8, clone formation, apoptosis, and cell cycle assay. The metastasis inhibition of CRC cells was determined by wound-healing assay. Western blotting was used to detect the NLRP3 inflammasome activation, pyroptosis, and apoptosis activation. Finally, the in vivo efficacy of 2',4'-DHC was verified by establishing CT26 and HT29 tumor transplant models in mice.

RESULTS

Here, our study firstly demonstrated that 2',4'-DHC inhibited the growth of CRC cells mainly by increasing CRC cell death and ameliorating tumor immunosuppressive environment, which is verified by inducing apoptosis and pyroptosis by regulating caspase-3/4/11, arresting cell cycle in G2/M phase, suppressing the migration of CRC cells, and inhibiting NLRP3 inflammasome activation through inhibiting the NF-κB pathway, enhancing the anticancer immune response by increasing the infiltration of T cells and function of CD8+ cytotoxic T cells but decreasing the infiltration of CD11b+ CD206+ macrophages and function. Importantly, the administration of 2',4'-DHC decreased liver and spleen indexs to mice's normal levels and reduced the burden of CT26 and HT29 tumor-bearing in mice without pathological changes in the major organs.

CONCLUSION

2',4'-DHC inhibited CRC growth through various mechanisms, mainly by regulating NLRP3 inflammasome and caspase-3/4/11 activation. Considering the anti-tumor and immunomodulation roles of 2',4'-DHC, it might be a new direction for the development of new strategies to treat colorectal cancer.

Professional killers: The role of extracellular vesicles in the reciprocal interactions between natural killer, CD8+ cytotoxic T-cells and tumour cells

Extracellular vesicles (EVs) mediate the cross‐talk between cancer cells and the cells of the surrounding Tumour Microenvironment (TME). Professional killer cells include Natural Killer (NK) cells and CD8+ Cytotoxic T‐lymphocytes (CTLs), which represent some of the most effective immune defense mechanisms against cancer cells. Recent evidence supports the role of EVs released by NK cells and CTLs in killing cancer cells, paving the road to a possible therapeutic role for such EVs. This review article provides the state‐of‐the‐art knowledge on the role of NK‐ and CTL‐derived EVs as anticancer agents, focusing on the different functions of different sub‐types of EVs. We also reviewed the current knowledge on the effects of cancer‐derived EVs on NK cells and CTLs, identifying areas for future investigation in the emerging new field of EV‐mediated immunotherapy of cancer.

Immune oppression array elucidating immune escape and survival mechanisms in uveal melanoma

AIM

To examine the genetic profile of primary uveal melanoma (UM) as compared to UM in immune escape.

METHODS

Dendritic cells (DC) loaded with lysates of UM cells of high metastatic potential were used to stimulate CTLs(CTLs). When CTLs co-cultured with the UM cells, most UM cells could be eliminated. Survival UM cells grew slowly and were considered to be survival variants and examined by a microarray analysis. These differential genes were analyzed further with Venn Diagrams and functions related to immune escape. We additionally examined transcriptional changes of manually selected survival variants of UM cells and of clinical UM samples by quantitative real-time polymerase chain reaction (qRT-PCR), and analyzed the correlation of these expressions and patients' survival.

RESULTS

Gene expression analyses revealed a marked up-regulation of SLAMF7 and CCL22 and a significant down-regulation of KRT10, FXYD3 and ABCC2. The expression of these genes in the relapsed UM was significantly greater than those in primary UM. UM patients with overexpression of these genes had a shorter survival period as compared with those of their underexpression.

CONCLUSION

Gene expression, in particular of SLAMF7, CCL22, KRT10, FXYD3 and ABCC2, differed between primary UM cells and survival variants of UM cells.

Degradable emulsion as vaccine adjuvant reshapes antigen-specific immunity and thereby ameliorates vaccine efficacy

This study describes the feasibility and adjuvant mechanism of a degradable emulsion for tuning adaptive immune responses to a vaccine antigen. We featured a mouse model with ovalbumin (OVA) as the antigen to deepen our understanding of the properties of a degradable emulsion-based adjuvant, dubbed PELC, interacting with immune cells and to elucidate their roles in vaccine immunogenicity in vivo. First, we demonstrated that the emulsion, which is stabilized by an amphiphilic bioresorbable polymer, shows degradation in mimic human body conditions and considerable tolerance in vivo. Then, we confirmed the model protein could be loaded into the emulsion and released from the matrix in a sustained manner, subsequently driving the production of antigen-specific antibodies. We also comprehended that PELC not only recruits antigen-presenting cells (APCs) to the injection site but also induces the activation of the recruited APCs and migration to the draining lymph nodes. As an adjuvant for cancer immunotherapy, PELC-formulated OVA could strongly enhance antigen-specific T-cell responses as well as anti-tumor ability with respected to non-formulated OVA, using OVA protein/EG7 cells as a tumor antigen/tumor cell model. Accordingly, our data paved the way for the clinical application of degradable emulsions based on amphiphilic bioresorbable polymers as vaccine adjuvants.

Structure and Function of HLA-A*02-Restricted Hantaan Virus Cytotoxic T-Cell Epitope That Mediates Effective Protective Responses in HLA-A2.1/K(b) Transgenic Mice

Hantavirus infections cause severe emerging diseases in humans and are associated with high mortality rates; therefore, they have become a global public health concern. Our previous study showed that the CD8(+) T-cell epitope aa129-aa137 (FVVPILLKA, FA9) of the Hantaan virus (HTNV) nucleoprotein (NP), restricted by human leukocyte antigen (HLA)-A*02, induced specific CD8(+) T-cell responses that controlled HTNV infection in humans. However, the in vivo immunogenicity of peptide FA9 and the effect of FA9-specific CD8(+) T-cell immunity remain unclear. Here, based on a detailed structural analysis of the peptide FA9/HLA-A*0201 complex and functional investigations using HLA-A2.1/K(b) transgenic (Tg) mice, we found that the overall structure of the peptide FA9/HLA-A*0201 complex displayed a typical MHC class I fold with Val2 and Ala9 as primary anchor residues and Val3 and Leu7 as secondary anchor residues that allow peptide FA9 to bind tightly with an HLA-A*0201 molecule. Residues in the middle portion of peptide FA9 extruding out of the binding groove may be the sites that allow for recognition by T-cell receptors. Immunization with peptide FA9 in HLA-A2.1/K(b) Tg mice induced FA9-specific cytotoxic T-cell responses characterized by the induction of high expression levels of interferon-γ, tumor necrosis factor-α, granzyme B, and CD107a. In an HTNV challenge trial, significant reductions in the levels of both the antigens and the HTNV RNA loads were observed in the liver, spleen, and kidneys of Tg mice pre-vaccinated with peptide FA9. Thus, our findings highlight the ability of HTNV epitope-specific CD8(+) T-cell immunity to control HTNV and support the possibility that the HTNV-NP FA9 peptide, naturally processed in vivo in an HLA-A*02-restriction manner, may be a good candidate for the development HTNV peptide vaccines.