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Damage-associated molecular patterns (DAMPs) are danger signals (or alarmins) alerting immune cells through pattern recognition receptors (PRRs) to begin defense activity. Moreover, DAMPs are host biomolecules that can initiate a noninflammatory response to infection, and pathogen-associated molecular pattern (PAMPs) perpetuate the inflammatory response to infection. Many DAMPs are proteins that have defined intracellular functions and are released from dying cells after tissue injury or chemo-/radiotherapy. In the tumor microenvironment, DAMPs can be ligands for Toll-like receptors (TLRs) expressed on immune cells and induce cytokine production and T-cell activation. Moreover, DAMPs released from tumor cells can directly activate tumor-expressed TLRs that induce chemoresistance, migration, invasion, and metastasis. Furthermore, DAMP-induced chronic inflammation in the tumor microenvironment causes an increase in immunosuppressive populations, such as M2 macrophages, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs). Therefore, regulation of DAMP proteins can reduce excessive inflammation to create an immunogenic tumor microenvironment. Here, we review tumor-derived DAMP proteins as ligands of TLRs and discuss their association with immune cells, tumors, and the composition of the tumor microenvironment., Cancer: Boosting the right signals to suppress tumors Tumor cells killed by radiotherapy or chemotherapy release signaling molecules that stimulate both immune response and tumor aggressiveness; regulating these molecules could improve treatment efficacy. Tae Heung Kang, Yeong-Min Park, and co-workers at Konkuk University, Seoul, South Korea, have reviewed the role of damage-associated molecular patterns (DAMPs) in immunity and cancer. These signaling molecules act as danger signals, activating immune cells by binding to specific receptors. However, tumor cells have the same receptors, and DAMPs binding triggers chemoresistance and increases invasiveness. The researchers report that although DAMPs can trigger a helpful immune response, they can also cause chronic inflammation, which in turn promotes an immune suppression response, allowing tumors to escape immune detection. Improving our understanding of the functions of different DAMPs could improve our ability to boost the immune response and decrease tumor aggressiveness.

Chemotherapy promotes phosphatidylserine (PS) externalization in tumors undergoing apoptosis, forms an immunosuppressive tumor microenvironment (TME), and inhibits dendritic cell (DC) maturation and antigen presentation by binding PS receptors expressed in DCs, thereby limiting naive T cell education and activation. In this study, we demonstrate a selective nanocarrier system composed of annexin A5-labeled poly (lactide-co-glycolide) nanoparticles (PLGA_NPs) encapsulating tumor specific antigen or neoantigen, to target apoptotic tumor cells expressing PS as an innate immune checkpoint inhibitor (ICI) that induces active cancer immunotherapy. Moreover, PLGA_NPs enhanced tumor-specific antigen-based cytotoxic T cell immunity via the original function of DCs by converting the tumor antigen-rich environment. Therefore, chemotherapy combined with an immunomodulatory nanocarrier system demonstrated an enhanced anticancer immune response by increasing survival rates, immune-activating cells, and pro-inflammatory cytokines in the spleen and TME. In contrast, the tumor mass, immune-suppressive cells, and anti-inflammatory cytokines were decreased. Furthermore, the combination of a nanocarrier system with other ICIs against large tumors showed therapeutic efficacy by immunosuppression in the TME and further amplified the anticancer immunity of interferon gamma

Various cancer therapies, such as surgery, radiotherapy, chemotherapy, and immunotherapy, have been used to treat cancer. Among cancer immunotherapies, stimulators of interferon genes (STING) activate various immune cells and induce them to attack cancer cells. However, the secretion of type I interferon (IFN α and β) increases after stimulation of the immune cell as a side effect of STING agonist, thereby increasing the expression of programmed death-ligand 1 (PD-L1) in the tumor microenvironment (TME). Therefore, it is necessary to reduce the side effects of STING agonists and maximize cancer treatment by administering combination therapy. Tumor-bearing mice were treated with cisplatin, tumor-specific peptide, neoantigen, DMXAA (STING agonist), and immune checkpoint inhibitor (ICI). The combination vaccine group showed a reduction in tumor mass, an increased survival rate, and IFN-γ

The interaction between immune cells and phosphatidylserine (PS) molecules exposed on the surface of apoptotic-tumor bodies, such as those induced by chemotherapies, contributes to the formation of an immunosuppressive tumor microenvironment (TME). Annexin A5 (AnxA5) binds with high affinity to PS externalized by apoptotic cells, thereby hindering their interaction with immune cells. Here, we show that AnxA5 administration rescue the immunosuppressive state of the TME induced by chemotherapy. Due to the preferential homing of AnxA5 to the TME enriched with PS+ tumor cells, we demonstrate in vivo that fusing tumor-antigen peptide to AnxA5 significantly enhances its immunogenicity and antitumor efficacy when administered after chemotherapy. Also, the therapeutic antitumor effect of an AnxA5-peptide fusion can be further enhanced by administration of other immune checkpoint inhibitors. Our findings support the administration of AnxA5 following chemotherapy as a promising immune checkpoint inhibitor for cancer treatment., AnnexinV has been shown to bind phosphatidylserine expressed by chemotherapy-induced apoptotic cells increasing their immunogeneicity. Here, the authors demonstrate in a preclinical tumor model that fusing tumor-antigen peptide to Annexin V enhances its efficacy when administered after chemotherapy and with other immune checkpoint inhibitors.

Sepsis is a disease responsible for the death of almost all critical patients. Once infected by virus or bacteria, patients can die due to systemic inflammation within a short period of time. Cytokine storm plays an essential role in causing organ dysfunction and septic shock. Thus, inhibition of cytokine secretion is considered very important in sepsis therapy. In this study, we found that TFP, an antipsychotic drug mainly used to treat schizophrenia by suppressing dopamine secretion, inhibited cytokine release from activated immune cells both in vitro and in vivo. Trifluoperazine (TFP) decreased the levels of pro-inflammatory cytokines without altering their transcription level. In LPS-induced endotoxemia and cecal content injection (CCI) models, TFP intraperitoneal administration improved survival rate. Thus, TFP was considered to inhibit the secretion of proteins through a mechanism similar to that of W7, a calmodulin inhibitor. Finally, we confirmed that TFP treatment relieved organ damage by estimating the concentrations of aspartate transaminase (AST), alanine transaminase (ALT), and blood urea nitrogen (BUN) in the serum. Our findings were regarded as a new discovery of the function of TFP in treating sepsis patients. Key messages • TFP inhibits LPS-induced activation of DCs by suppressing pro-inflammatory cytokine. • Treatment of TFP increases survival of LPS-induced endotoxemia and CCI sepsis models. • TFP exerted a protective effect against tissue or organ damage in animal models. Electronic supplementary material The online version of this article (10.1007/s00109-019-01762-4) contains supplementary material, which is available to authorized users.

Background: Cancer immunotherapy is widely used as a treatment for cancer that works by improving the immune system with fewer side effects than conventional methods. Neoantigen vaccines are one form of immunotherapy that use cancer-specific neoantigens that are extracted from cancer patients and are not recognized by normal cells in the immune system.Methods: In this study, mutant genes of 4T1 mouse breast cancer cells were identified by direct sequence analysis using tumor-specific MHC I (Major Histocompatibility Complex) or MHC II epitopes through in vivo experiments. Results: The neoantigen vaccine with mutant CD4+ or CD8+ T cell-reactive neoantigen peptides was shown to inhibit tumor growth, increase long-term survival, and induce the secretion of IFN-γ (Interferon gamma) in the cisplatin-treated mouse models. In particular, mutant CD4+ T cell neoantigen peptides induced full potential anti-tumor effects, whereas dual treatment with CD4+ (Cluster of differentiation 4) and CD8+ (Cluster of differentiation 8) T cell neoantigen peptides increased the suppression of tumor growth. Moreover, the combination of neoantigen vaccine with mutant CD4+ T cell neoantigen peptide and anti-PD-L1 (Programmed death-ligand 1) as an immune checkpoint inhibitor (ICI) has been shown to have synergistic therapeutic effects in cisplatin-treated mouse models. Conclusion: This study, therefore, proved that cancer cell-derived neoantigens have great potential to induce immunogenic responses and cancer treatment effects, along with synergistic efficiency when applied to various combinational therapies. Through the methods that were used in our experiments, we could contribute to the development of new adjuvants for evaluating efficacy, discovering unfound neoantigens, and investigating immune checkpoint blockade antibodies for non-clinical studies.

Immune checkpoint inhibitors (ICIs), including programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 have shown promising cancer clinical outcomes. However, IC therapy has low patient response rates (10%-15%). Thus, ICIs and sufficient antigen combinations into the tumor microenvironment (TME) is important to produce strong tumor-specific adaptive immune responses. Mice were treated with cisplatin, and human cancer cells were exposed to inflammatory cytokines, to confirm increased PD-L1 and major histocompatibility complex (MHC) I expression by tumor cells or dendritic cells. TC-1, CT26, B16-F1, or B16-F10 tumor cells, and bone marrow-derived dendritic cells, were treated with interferon (IFN)-β, IFN-γ, or tumor necrosis factor-α to identify the molecular mechanisms underlying tumor PD-L1 and MHC I upregulation, and to examine MHC I, CD40, CD80, CD86, or PD-L1 levels, respectively. For synergistic combination therapy, αPD-L1 monoclonal antibody (mAb) covalently linked to the long E7 peptide was generated. Chemotherapy shifted the TME to express high PD-L1 and MHC I, resulting in targeted ICI cargo delivery and enhanced generation and activation of tumor antigen-specific T cells. Synergistic effects of vaccination and IC blockade in the TME were demonstrated using an anti-PD-L1 mAb covalently conjugated to the E7 long peptide.

Cancer immunotherapy has fewer side effects and higher efficiency than conventional methods. Dendritic cell (DC)-based vaccine, a cancer immunotherapeutic, is prepared by processing mature DCs and pulsing with tumor antigen peptide ex vivo, to induce the activation of tumor-specific T lymphocytes followed by tumor clearance in vivo. Unfortunately, clinical trials of this method mostly failed due to low patient response, possibly due to the absence of novel adjuvants that induce DC maturation through Toll-like receptor (TLR) signals. Interestingly, immune checkpoint inhibitor (ICI) therapy has shown remarkable anti-tumor efficacy when combined with cancer vaccines. In this study, we identified 60S acidic ribosomal protein P2 (RPLP2) through pull-down assay using human cancer cells derived proteins that binds to Toll-like receptor 4 (TLR4). Recombinant RPLP2 induced maturation and activation of DCs in vitro. This DC-based vaccine, followed by pulsing with tumor-specific antigen, has shown to significantly increase tumor-specific CD8+IFN-γ+ T cells, and improved both tumor prevention and tumor treatment effects in vivo. The adjuvant effects of RPLP2 were shown to be dependent on TLR4 using TLR4 knockout mice. Moreover, ICIs that suppress the tumor evasion mechanism showed synergistic effects on tumor treatment when combined with these vaccines.

Dendritic cell (DC)-based vaccines are recognized as a promising immunotherapeutic strategy against cancer. Various adjuvants are often incorporated to enhance the modest immunogenicity of DC vaccines. More specifically, many of the commonly used adjuvants are derived from bacteria. In the current study, we evaluate the use of apoptosis inhibitor 5 (API5), a damage-associated molecular pattern expressed by many human cancer cells, as a novel DC vaccine adjuvant. We showed that API5 can prompt activation and maturation of DCs and activate NFkB by stimulating the Toll-like receptor signaling pathway. We also demonstrated that vaccination with API5-treated DCs pulsed with OVA, E7, or AH1-A5 peptides led to the generation of OVA, E7, or AH1-A5-specific CD8 + T cells and memory T cells, which is associated with long term tumor protection and antitumor effects in mice, against EG.7, TC-1, and CT26 tumors. Additionally, we determined that API5-mediated DC activation and immune stimulation are dependent on TLR4. Lastly, we showed that the API5 protein sequence fragment that is proximal to its leucine zipper motif is responsible for the adjuvant effects exerted by API5. Our data provide evidence that support the use of API5 as a promising adjuvant for DC-based therapies, which can be applied in combination with other cancer therapies. Most notably, our results further support the continued investigation of human-based adjuvants.

Introduction: After cancer treatment using chemotherapy and radiotherapy, tumor microenvironment continually occurs inflammation, which depend on damage-associated molecular pattern (DAMPs) released from apoptotic tumor cells. In this case, tumor microenvironment is regarded as inflammation zone and induce various immune cells infiltration, pro- and anti-inflammatory cytokines production and interaction between immune cells and cancer cells. These, a dynamic and complex microenvironment induce a favorable state for tumor growth. Thus, recent studies assert that it is important to regulate excessively increased inflammatory response in the tumor microenvironment accordingly. Annexin V is a Ca2+-dependent phospholipid binding pro[[Unsupported Character - Codename ­]]tein and known to bind to exposed phosphatidylserine on the apoptotic cells. Several groups and our study have recently demonstrated that annexin V has anti-inflammatory effects by inhibiting bone-marrow derived dendritic cell (BMDCs) activation and pro-inflammtory cytokine production. So, we suggest that Annexin V as a therapeutic approach for controlling inflammatory response in cancer patients having increased inflammation in tumor microenvironment. Methods: The size and purity of recombinant proteins were assessed using SDS-PAGE. IVIS imaging system used to characterize the accumulation of Annexin V containing protein into tumor loci in tumor-bearing mice. Therapeutic efficacy was confirmed tumor-specific CD8+ T cells in PBMCs and splenocytes by Flow cytometry analysis. pro-, anti- inflammtory cytokines and various immune cells infiltration in tumor microenvironment were examined by ELISA and FACS. Cytotoxicity by tumor-specific CD8+ T cells of Luciferase-expressing tumor cells was observed by representative luminescence imaging system. Results: The Targeting efficiency of Annexin V protein into tumor microenvironment was increased compared to control. Therapeutic efficacy was demostrated activation of tumor-specific CD8+ T cells (P < 0.001), inhibition of tumor growth (P < 0.05) and increase of survival (P < 0.05) in tumor bearing mouse compared to control. AnnexinV protein administration was decreased significantly TGF-beta 1 cytokine production (P < 0.001) and immunosuppressive cells infiltration (P < 0.001) in tumor microenviroment compared to non-treated group. Conclusion: We identified multiple role of Annexin V protein, which has capacity of apoptotic tumor cell target, as regulator of excessive inflammation in tumor microenvironment. This results could primarily pave the road for the development of anti-tumor immunotherapy. Citation Format: Jung Hwa Park, Young Seob Kim, Hyun Jin Park, Gun Young Jang, T.c. Wu, Yeong-Min Park, Tae Heung Kang. AnnexinV: Multifunctional anticancer immunotherapeutic protein in tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4066.