Cellular Mechanism of Newly Synthesized Indoledione Derivative-induced Immunological Death of Tumor Cell

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.

Induction of immunogenic cell death of tumors by newly synthesized heterocyclic quinone derivative

Many cancer types are serious diseases causing mortality, and new therapeutics with improved efficacy and safety are required. Immuno-(cell)-therapy is considered as one of the promising therapeutic strategies for curing intractable cancer. In this study, we tested R2016, a newly developed heterocyclic quinone derivative, for induction of immunogenic tumor cell death and as a possible novel immunochemotherapeutic. We studied the anti-cancer effects of R2016 against LLC, a lung cancer cell line and B16F10, a melanoma cell line. LLC (non-immunogenic) and B16F10 (immunogenic) cells were killed by R2016 in dose-dependent manner. R2016 reduced the viability of both LLC and B16F10 tumor cells by inducing apoptosis and necrosis, while it demonstrated no cytotoxicity against normal splenocytes. Expression of immunogenic death markers on the cell surface of R2016 treated tumor cells including calreticulin (CRT) and heat shock proteins (HSPs) was increased along with the induction of their genes. Increased CRT expression correlated with dendritic cell (DC) uptake of dying tumor cells: the proportion of CRT⁺CD11c⁺cells was increased in the R2016-treated group. The gene transcription of Calr3, Hspb1, and Tnfaip6, which are related to immunogenicity induction of dead cells, was up-regulated in the R2016 treated tumor cells. On the other hand, ANGPT1, FGF7, and URGCP gene levels were down-regulated by R2016 treatment. This data suggests that R2016 induced immunogenic tumor cell death, and suggests R2016 as an effective anti-tumor immunochemotherapeutic modality.

Immunogenic Cell Death Induced by Ginsenoside Rg3: Significance in Dendritic Cell-based Anti-tumor Immunotherapy

Cancer is one of the leading causes of morbidity and mortality worldwide; therefore there is a need to discover new therapeutic modules with improved efficacy and safety. Immune-(cell) therapy is a promising therapeutic strategy for the treatment of intractable cancers. The effectiveness of certain chemotherapeutics in inducing immunogenic tumor cell death thus promoting cancer eradication has been reported. Ginsenoside Rg3 is a ginseng saponin that has antitumor and immunomodulatory activity. In this study, we treated tumor cells with Rg3 to verify the significance of inducing immunogenic tumor cell death in antitumor therapy, especially in DC-based immunotherapy. Rg3 killed the both immunogenic (B16F10 melanoma cells) and non-immunogenic (LLC: Lewis Lung Carcinoma cells) tumor cells by inducing apoptosis. Surface expression of immunogenic death markers including calreticulin and heat shock proteins and the transcription of relevant genes were increased in the Rg3-dying tumor. Increased calreticulin expression was directly related to the uptake of dying tumor cells by dendritic cells (DCs): the proportion of CRT⁺ CD11c⁺ cells was increased in the Rg3-treated group. Interestingly, tumor cells dying by immunogenic cell death secreted IFN-γ, an effector molecule for antitumor activity in T cells. Along with the Rg3-induced suppression of pro-angiogenic (TNF-α) and immunosuppressive cytokine (TGF-β) secretion, IFN-γ production from the Rg3-treated tumor cells may also indicate Rg3 as an effective anticancer immunotherapeutic strategy. The data clearly suggests that Rg3-induced immunogenic tumor cell death due its cytotoxic effect and its ability to induce DC function. This indicates that Rg3 may be an effective immunotherapeutic strategy.

Chemotherapeutic candidate inducing immunological death of human tumor cell lines

The immunological death induction by EY-6 on the human tumor cell lines was screened. Human colon carcinoma (HCT15, HCT116), gastric carcinoma (MKN74, SNU668), and myeloma (KMS20, KMS26, KMS34) cells were died by EY-6 treatment with dose-dependent manner. CRT expression, a typical marker for the immunological death, was increased on the EY-6-treated colorectal and gastric cancer cells. Interestingly, the effects on the myeloma cell lines were complicated showing cell line dependent differential modulation. Cytokine secretion from the EY-6 treated tumor cells were dose and cell-dependent. IFN-γ and IL-12 secretion was increased in the treated cells (200% to over 1000% of non-treated control), except HCT116, SNU668 and KMS26 cells which their secretion was declined by EY-6. Data suggest the potential of EY-6 as a new type of immuno-chemotherapeutics inducing tumor-specific cell death. Further studies are planned to confirm the efficacy of EY-6 including in vivo study.