A fully synthetic self-adjuvanting cancer vaccine candidate was constructed through covalent conjugation of invariant natural killer T (iNKT) cell ligand α-galactosylceramide (αGalCer) with sialyl Tn (STn), a representative tumor-associated carbohydrate antigen (TACA). This two-component vaccine STn-αGalCer is devoid of antigenic peptide, featuring the well-defined structure with high simplicity. STn-αGalCer showed remarkable efficacy in inducing antibody class switching from IgM to STn-specific IgG. Subtypes of IgG antibody were primarily IgG1 and IgG3.
Tumor-draining lymph nodes (TDLNs) are the primary sites to initiate immune responses against cancer, as well as the origin of metastasis for most breast cancer cases. Reverting the immunosuppression microenvironment in TDLNs is critical to improving the outcome of the malignancy, though still a big technical challenge. In this study, a type of smart exosomes was developed in which the exosome surface was functionally engineered with CD62L (L-selectin, a gene for lymphocyte homing to lymph nodes) and OX40L (CD134L, a gene for effector T cell expansion and regulatory T cell [Treg] inhibition) by forced expression of the genes in the donor cells. Compared with control exosomes, the smart exosomes displayed strong TDLN homing capacity in the 4T1 syngeneic mouse model. Moreover, injection of the smart exosomes activated effector T cells and inhibited Treg induction, thereby amplifying the antitumor immune response and inhibiting tumor development. Together, the engineered smart exosomes provide a novel nanoplatform for TDLN-targeted delivery and cancer immunotherapy.
The aim of the present study was to investigate the effect of fecal microbiota transplantation (FMT) on the acute inflammatory response in a murine model of dextran sulfate sodium (DSS)-induced colitis, and to delineate the putative underlying mechanism(s). Mice were divided into four groups, namely the normal control, DSS, 5-aminosalicylic acid (5-ASA) and FMT group. Mice in the DSS, 5-ASA and FMT groups were orally administered 3% DSS (w/v) solution for 7 days to induce colitis. On days 1, 3, 5 and 7, mice in the DSS, 5-ASA and FMT groups were respectively administered 0.5% carboxymethylcellulose sodium, 5-ASA suspension and fecal suspension by enema. The disease activity index of each mouse was calculated on a daily basis. All mice were sacrificed on day 8, and the length of their colons was measured. Myeloperoxidase (MPO) activity, and the levels of tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-10 in the colon tissues of each group were also measured. Compared with that in the DSS group, FMT ameliorated the severity of inflammation due to ulcerative colitis in mice, which was accompanied by a significantly decreased MPO activity, reduced levels of TNF-α and IL-1β, and an increased level of IL-10 in colon tissue (all P<0.05). Taken together, these results demonstrated that FMT exerted a therapeutic effect on experimental colitis in mice, and the associated mechanism is likely to involve the remodeling of the intestinal flora and regulation of intestinal T-cell immunity homeostasis.
Abstract. The aim of the present study was to explore the effect of knocking down the expression of β-catenin by small interference (si)RNA on the activity of the Wnt/β-catenin signaling pathway, and the proliferation, apoptosis and invasion abilities of the human colon cancer cell line SW480. For that purpose, double-stranded siRNA targeting β-catenin (β-catenin-siRNA) was synthesized and transfected into SW480 cells. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to detect the messenger (m)RNA and protein levels of β-catenin in SW480 cells. To detect cell proliferation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, while cell apoptosis and caspase-3 activity were detected by flow cytometry and caspase-3 activity assay, respectively. Matrigel invasion assay was performed to detect the influence of siRNA-mediated gene silencing on the invasion and metastasis of SW480 cells in vitro. The results of RT-PCR and western blot analysis demonstrated that, compared with the blank control, negative control and liposome groups, β-catenin-siRNA transfected SW480 cells had significantly decreased mRNA and protein levels of β-catenin. In addition, following β-catenin-siRNA transfection, the proliferation of SW480 cells was significantly lower than that of the blank control, negative control and liposome groups, while the apoptosis rate increased in β-catenin-siRNA transfected cells, compared with the aforementioned groups. Invasion assay showed that, following β-catenin-siRNA transfection, the number of SW480 cells infiltrating through the Matrigel membrane was significantly lower than that of the blank control, negative control and liposome groups. Following β-catenin-siRNA transfection, the caspase-3 activity in SW480 cells was lower than that in the blank control, negative control and liposome groups. These results indicate that siRNA-mediated silencing of β-catenin could inhibit the proliferation and invasion of SW480 cells and induce apoptosis, thus providing novel potential strategies for the clinical treatment of colon cancer, and may serve as a novel target for cancer therapy.
Pyroptosis is a newly discovered inflammatory form of programmed cell death, which promotes systemic immune response in cancer immunotherapy. GSDMD is one of the key molecules executing pyroptosis, while therapeutical delivery of GSDMD to tumor cells is of great challenge. In this study, an extracellular vesicles‐based GSDMD‐N mRNA delivery system (namely EVTx) is developed for enhanced cancer immunotherapy, with GSDMD‐N mRNA encapsulated inside, Ce6 (Chlorin e6 (Ce6), a hydrophilic sensitizer) incorporated into extracellular vesicular membrane, and HER2 antibody displayed onto the surface. Briefly, GSDMD‐N mRNA is translationally repressed in donor cells by optimized puromycin, ensuring the cell viability and facilitating the mRNA encapsulation into extracellular vesicles. When targeted and delivered into HER2+ breast cancer cells by the engineered extracellular vesicles, the translational repression is unleashed in the recipient cells as the puromycin is diluted and additionally inactivated by sonodynamic treatment as the extracellular vesicles are armed with Ce6, allowing GSDMD‐N translation and pyroptosis induction. In addition, sonodynamic treatment also induces cell death in the recipient cells. In the SKBR3‐ and HER2 transfected 4T1‐ inoculated breast tumor mouse models, the engineered EVTx efficiently induces a powerful tumor immune response and suppressed tumor growth, providing a nanoplatform for cancer immunotherapy.
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