PAUF Induces Migration of Human Pancreatic Cancer Cells Exclusively via the TLR4/MyD88/NF-κB Signaling Pathway.

PAUF, a tumor-promoting protein secreted by cancer cells, exerts paracrine effects on immune cells through TLR4 receptors expressed on immune cell surfaces. This study aimed to investigate if PAUF elicits autocrine effects on pancreatic cancer (PC) cells through TLR4, a receptor that is overexpressed on PC cells. In this study, TLR4 expression was detected in PC cells only, but not normal pancreatic cells. The migration of TLR4 high-expressing PC cells (i.e., BxPC-3) was reduced by a selective TLR4 inhibitor, in a dose-dependent manner. Using TLR4 overexpressed and knockout PC cell lines, we observed direct PAUF-TLR4 binding on the PC cell surfaces, and that PAUF-induced cancer migration may be mediated exclusively through the TLR4 receptor. Further experiments showed that PAUF signaling was passed down through the TLR4/MyD88 pathway without the involvement of the TLR4/TRIF pathway. TLR4 knockout also downregulated PC membrane PD-L1 expression, which was not influenced by PAUF. To the best of our knowledge, TLR4 is the first receptor identified on cancer cells that mediates PAUF's migration-promoting effect. The results of this study enhanced our understanding of the mechanism of PAUF-induced tumor-promoting effects and suggests that TLR4 expression on cancer cells may be an important biomarker for anti-PAUF treatment.

Enhancement of anticancer immunity by immunomodulation of apoptotic tumor cells using annexin A5 protein-labeled nanocarrier system.

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+ (IFN-γ) CD8+ (cluster of differentiation 8) T cells. Taken together, our Annexin A5-labeled PLGA-NPs can be applied in various combination therapeutic techniques for cancer immunotherapy.

Improvement of STING-mediated cancer immunotherapy using immune checkpoint inhibitors as a game-changer.

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 ß) 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+ (interferon gamma) CD8+ (cluster of differentiation 8) T cells in the spleen and TME. The distribution of immune cells in the spleen and TME was confirmed, and the number of active immune cells increased, whereas that of immunosuppressive cells decreased. When measuring cytokine levels in the tumor and serum, the levels of pro-inflammatory cytokines increased and anti-inflammatory cytokines decreased. This study demonstrated that when various cancer therapies are combined to treat cancer, it can lead to an anticancer immune synergistic effect by increasing the immune response and reducing side effects.

Immune checkpoint silencing using RNAi-incorporated nanoparticles enhances antitumor immunity and therapeutic efficacy compared with antibody-based approaches.

BACKGROUND: Cytotoxic CD8+ T cell-based cancer immunotherapy has been extensively studied and applied, however, tumor cells are known to evade immune responses through the expression of immune checkpoints, such as programmed death ligand 1 (PD-L1). To overcome these issues, antibody-based immune checkpoint blockades (eg, antiprogrammed cell death 1 (anti-PD-1) and anti-PD-L1) have been revolutionized to improve immune responses. However, their therapeutic efficacy is limited to 15%-20% of the overall objective response rate. Moreover, PD-L1 is secreted from tumor cells, which can interrupt antibody-mediated immune reactions in the tumor microenvironment. METHODS: We developed poly(lactic-co-glycolic acid) nanoparticles (PLGA-NPs) encapsulating PD-L1 small interfering RNA (siRNA) and PD-1 siRNA, as a delivery platform to silence immune checkpoints. This study used the TC-1 and EG7 tumor models to determine the potential therapeutic efficacy of the PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs, on administration twice per week for 4 weeks. Moreover, we observed combination effect of PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs and PLGA (antigen+adjuvant)-NPs using TC-1 and EG7 tumor-bearing mouse models. RESULTS: PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs boosted the host immune reaction by restoring CD8+ T cell function and promoting cytotoxic CD8+ T cell responses. We demonstrated that the combination of NP-based therapeutic vaccine and PLGA (siRNA)-NPs resulted in significant inhibition of tumor growth compared with the control and antibody-based treatments (p<0.001). The proposed system significantly inhibited tumor growth compared with the antibody-based approaches. CONCLUSION: Our findings suggest a potential combination approach for cancer immunotherapy using PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs and PLGA (antigen+adjuvant)-NPs as novel immune checkpoint silencing agents.

A novel form of immunotherapy using antigen peptides conjugated on PD-L1 antibody.

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)-ß, 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.

NIR irradiation-controlled drug release utilizing injectable hydrogels containing gold-labeled liposomes for the treatment of melanoma cancer.

Drug-based chemotherapy is associated with serious side effects. We developed a chemotherapeutic system comprising a chitosan hydrogel (CH-HG) containing gold cluster-labeled liposomal doxorubicin (DOX) (CH-HG-GLDOX) as an injectable drug depot system. CH-HG-GLDOX can be directly injected into tumor tissue without a surgical procedure, allowing this system to act as a reservoir for liposomal DOX. CH-HG-GLDOX enhanced the retention time of DOX in tumor tissue and controlled its release in response to near-infrared (NIR) irradiation, resulting in significant inhibition of tumor growth and reduced DOX-related toxicity. The combined effect of CH-HG-GLDOX and poly (D,L-lactide-co-glycolic acid) nanoparticle-based vaccines increased cytotoxic CD8+ T cell immunity, leading to enhanced synergistic therapeutic efficacy. CH-HG-GLDOX provides an advanced therapeutic approach for local drug delivery and controlled release of DOX, resulting in reduced toxicity. Here, we suggest a combination strategy for chemo- and immunotherapies, as well as in nanomedicine applications. STATEMENT OF SIGNIFICANCE: We developed an injectable hydrogel containing gold cluster-labeled liposomes for sustained drug release at the tumor site. Moreover, we demonstrated the combined therapeutic efficacy of a hydrogel system and a nanoparticle-based immunotherapeutic vaccine for melanoma cancer. Thus, we show a potential combination approach for chemo- and immunotherapies for cancer treatment.

Improvement of DC-based vaccines using adjuvant TLR4-binding 60S acidic ribosomal protein P2 and immune checkpoint inhibitors.

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.

Interactions between tumor-derived proteins and Toll-like receptors.

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.

Efficacy of Combination Therapy with Linalool and Doxorubicin Encapsulated by Liposomes as a Two-in-One Hybrid Carrier System for Epithelial Ovarian Carcinoma.

BACKGROUND: Epithelial ovarian cancer (EOC) is a fatal gynecologic malignancy that is usually treated with chemotherapy after surgery. However, patients who receive chemotherapy experience severe side effects because of the inherent toxicity and high dose of chemotherapeutics. To overcome these issues, we suggest a combination therapeutic strategy using liposomes encapsulating linalool nanoemulsions (LN-NEs) and doxorubicin (DOX), a chemotherapeutic drug, to increase their synergistic antitumor efficacy and reduce the incidence of side effects from chemotherapeutics for EOC. METHODS: The physical properties of LN-NE-DOX-liposomes were characterized by light scattering with a particle size analyzer. Cell viability was determined by MTT assay. Therapeutic efficacy was evaluated in a mouse HeyA8 EOC tumor model of ovarian carcinoma. Additionally, biochemical toxicity was analyzed for levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and blood urea nitrogen (BUN) using BALB/c nude mice. RESULTS: The size of the liposomes encapsulating LN-NEs and DOX (LN-NE-DOX-liposomes) was 267.0 ± 4.6 nm, with a loading efficiency of 55.1 ± 3.1% and 27.2 ± 0.9% for linalool and DOX, respectively. Cell viability after treatment with LN-NE-DOX-liposomes was significantly decreased compared to that of cells treated with DOX liposomes, and apoptosis was significantly increased. Additionally, LN-NE-DOX-liposomes significantly inhibited HeyA8 EOC tumor growth compared to that of the control (p < 0.01) and DOX-liposome-treated groups (p < 0.05), while decreasing cell proliferation (Ki67) and microvessel density (CD31), and promoting apoptosis (caspase-3) compared to the control (p < 0.05). Moreover, the liposomal formulations induced no significant differences in biochemical toxicity (AST, ALT, and BUN) compared to healthy control mice, indicating that the liposomal formulations showed no overt toxicity in mice. CONCLUSION: This study demonstrates that the production of LN-NE-DOX-liposomes is a pivotal approach for EOC treatment, suggesting a novel combination therapeutic strategy.

Selective Tumor-Specific Antigen Delivery to Dendritic Cells Using Mannose-Labeled Poly(d, l-lactide-co-glycolide) Nanoparticles for Cancer Immunotherapy.

A key issue in dendritic cell (DC)-based cancer immunotherapy is the effective delivery of tumor-specific antigens to DCs. To deliver antigens, non-viral vaccine system has been used in ex vivo manipulation. However, ex vivo manipulation is time-consuming, lacks quality control of DCs, and demonstrates low antigen delivery efficiency, which implicates that there are serious problems in therapeutic DC preparations. Therefore, we developed mannose (MN)-labeled poly(d, l-lactide-co-glycolide) (PLGA) nanoparticles (MN-PLGA-NPs) encapsulating tumor-specific antigens for targeted delivery to mannose receptors (MN-R) on DC surfaces without ex vivo manipulation. The MN-PLGA-NPs showed DC-selective delivery in tumor-bearing mice, leading to highly mature and activated DCs, which migrated to lymphoid organs, resulting in activation of cytotoxic CD8+ T cells. Additionally, MN-PLGA-NPs showed significant therapeutic efficacy in EG7 lymphoma tumorbearing mice. Our nano-platform technology can be used as a vaccine system to bypass ex vivo manipulation and enhance targeted delivery of tumor-specific antigens to DCs, which is well-suited for cancer immunotherapy.

Annexin A5 as an immune checkpoint inhibitor and tumor-homing molecule for cancer treatment.

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.

TLR9 acts as a sensor for tumor-released DNA to modulate anti-tumor immunity after chemotherapy.

The tumor microenvironment exists in a state of dynamic equilibrium, in which a balance of agonist and antagonist signals govern the anti-tumor immune responses. Previous studies have shown that chemotherapy could shift this balance in favor of agonistic signals for the anti-tumor immune responses mounted by CD8+ cytotoxic T lymphocytes (CTL), providing sufficiently high antigen density within the tumor. We undertook the current study to characterize the anti-tumor immune response following chemotherapy and its underlying mechanisms. We show that this 'adjuvant effect' of chemotherapy is, at least partially, mediated by the release of tumor DNA and acts through the Toll-like receptor 9 (TLR9) pathway. We found that tumor-released DNA causes accumulation, antigen uptake, and maturation of dendritic cells (DCs) in the tumor in a TLR9-dependent manner. These DCs subsequently migrate into the draining lymph nodes and prime tumor-specific CTLs. Our study provides novel insights to the molecular and cellular mechanisms by which chemotherapy converts the tumor microenvironment into a site permissive for the activation of a potent tumor-specific adaptive immune response.

Brown Adipocyte and Splenocyte Co-Culture Maintains Regulatory T Cell Subset in Intermittent Hypobaric Conditions.

Background: Brown adipocytes have thermogenic characteristics in neonates and elicit anti-inflammatory responses. We postulated that thermogenic brown adipocytes produce distinctive intercellular effects in a hypobaric state. The purpose of this study is to analyze the correlation between brown adipocyte and regulatory T cell (Treg) expression under intermittent hypobaric conditions. Methods: Brown and white adipocytes were harvested from the interscapular and flank areas of C57BL6 mice, respectively. Adipocytes were cultured with syngeneic splenocytes after isolation and differentiation. Intermittent hypobaric conditions were generated using cyclic negative pressure application for 48 h in both groups of adipocytes. Expression levels of Tregs (CD4 + CD25 + Foxp3 + T cells), cytokines [tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10), and the programmed death-ligand 1 (PD-L1)] co-inhibitory ligand were examined. Results: Splenocytes, cultured with brown and white adipocytes, exhibited comparable Treg expression in a normobaric state. Under hypobaric conditions, brown adipocytes maintained a subset of Tregs. However, a decrease in Tregs was found in the white adipocyte group. TNF-α levels increased in both groups under hypobaric conditions. In the brown adipocyte group, anti-inflammatory IL-10 expression increased significantly; meanwhile, IL-10 expression decreased in the white adipocyte group. PD-L1 levels increased more significantly in brown adipocytes than in white adipocytes under hypobaric conditions. Conclusion: Both brown and white adipocytes support Treg expression when they are cultured with splenocytes. Of note, brown adipocytes maintained Treg expression in intermittent hypobaric conditions. Anti-inflammatory cytokines and co-inhibitory ligands mediate the immunomodulatory effects of brown adipocytes under altered atmospheric conditions. Brown adipocytes showed the feasibility as a source of adjustment in physical stresses.

Lyophilizable and Multifaceted Toll-like Receptor 7/8 Agonist-Loaded Nanoemulsion for the Reprogramming of Tumor Microenvironments and Enhanced Cancer Immunotherapy.

The low therapeutic efficacy of current cancer immunotherapy is related to nonimmunogenic and immunosuppressive tumor microenvironments (TMEs). To overcome these limitations, both the immune priming of antitumoral lymphocytes and the reprogramming of immunosuppressive factors in TMEs are essential. Here, we suggest a nanoemulsion (NE)-based immunotherapeutic platform that can not only modulate tumor-induced suppression but also induce an effective cell-mediated immune response for T cell proliferation. Multifunctional NEs can be fabricated by integrating the efficacy of NEs as delivery systems and the multifaceted immunomodulation characteristics (i.e., immunostimulation and reprogramming of immunosuppression) of small molecule-based Toll-like receptor 7/8 agonists. Local in situ vaccination of melanoma and cervical tumor models with tumor antigens (protein and peptide) adjuvanted with NE loaded with TLR7/8 agonists [NE (TLR7/8a)] induced the recruitment and activation of innate immune cells, infiltration of lymphocytes, and polarization of tumor-associated M2 macrophages, which resulted in inhibition of tumor growth and prolonged survival in both primary and rechallenged tumor models. Antibody-depletion experiments also suggested that macrophages, type I IFN (IFN-α and IFN-ß), CD8+ T cells, and NK1.1+ cells contributed to the antitumor effect of NE (TLR7/8a). The combination of antitumoral lymphocytes and reprogramming of immunosuppressive TMEs induced by NE (TLR7/8a) treatment evoked a synergistic antitumor immune response with immune checkpoint blockade therapy (anti-PD-1 and anti-PD-L1).

Syringeable immunotherapeutic nanogel reshapes tumor microenvironment and prevents tumor metastasis and recurrence.

The low response rate of current cancer immunotherapy suggests the presence of few antigen-specific T cells and a high number of immunosuppressive factors in tumor microenvironment (TME). Here, we develop a syringeable immunomodulatory multidomain nanogel (iGel) that overcomes the limitation by reprogramming of the pro-tumoral TME to antitumoral immune niches. Local and extended release of immunomodulatory drugs from iGel deplete immunosuppressive cells, while inducing immunogenic cell death and increased immunogenicity. When iGel is applied as a local postsurgical treatment, both systemic antitumor immunity and a memory T cell response are generated, and the recurrence and metastasis of tumors to lungs and other organs are significantly inhibited. Reshaping of the TME using iGel also reverts non-responding groups to checkpoint blockade therapies into responding groups. The iGel is expected as an immunotherapeutic platform that can reshape immunosuppressive TMEs and synergize cancer immunotherapy with checkpoint therapies, with minimized systemic toxicity.

Drug repositioning of TANK-binding kinase 1 inhibitor CYT387 as an alternative for the treatment of Gram-negative bacterial sepsis.

There is currently no specific drug for the treatment of sepsis and antibiotic administration is considered the best option, despite numerous issues. Therefore, the development of drugs to control the pathogen-induced inflammatory responses associated with sepsis is essential. To address this, our study examined the transcriptomes of lipopolysaccharide (LPS)-induced dendritic cells (DCs), identifying TANK-binding kinase1 (Tbk1) as a key factor involved in the inflammatory response. These data suggested drug repositioning of the Tbk1 inhibitor CYT387, currently used for the treatment of myelofibrosis and some cancers, as a candidate for regulating the LPS-induced inflammatory response. CYT387 also inhibited pro-inflammatory cytokine and surface molecule expression by mature DCs after LPS exposure. These effects correlated with both Akt phosphorylation and IκBα degradation. Finally, CYT387 demonstrated therapeutic effects in LPS-induced endotoxemia and Escherichia coli K1-induced mouse models of sepsis and decreased the expression of pro-inflammatory cytokines. In conclusion, our study suggests that drug repositioning of CYT387 may serve as a potential therapeutic for sepsis.

Endoplasmic reticulum stress enhances the antigen-specific T cell immune responses and therapeutic antitumor effects generated by therapeutic HPV vaccines.

BACKGROUND: Endoplasmic reticulum stress has a profound effect on cancer cell proliferation and survival, and also has the capacity to activate cells of the adaptive immune system. Multimodal treatment methods that utilize and combine conventional cancer therapies with antigen-specific immunotherapies have emerged as promising approaches for the treatment and control of cancer. However, it is not well known whether endoplasmic reticulum stress-inducing agents can influence the efficacy of tumor antigen-targeting vaccines. METHODS: In the past, we developed a therapeutic human papillomavirus (HPV) DNA vaccine that encodes for calreticulin (CRT) linked to the HPV16 E7 antigen (CRT/E7). In this study, we utilize the CRT/E7 and further encode for an endoplasmic reticulum (ER) stress-inducing agent, 3-bromopyruvate (3-BrPA), in a preclinical model, by harnessing its potential to enhance HPV16 E7-specific CD8+ T cell immune responses as well as antitumor effects against E7-expressing tumors (TC-1 cells). E7-specific CD8+ T cells were added to evaluate the cytotoxicity of luciferase-expressing TC-1 tumor cells treated with 3-BrPA in vitro, as measured with an IVIS Luminescence Imaging System. We also determined the levels of ER stress markers in 3-BrPA-treated TC-1 cells. TC-1 tumor-bearing mice were treated with either 3-BrPA (10 mg/kg, intraperitoneal injection) and/or CRT/E7 DNA vaccine (30 µg/mouse). RESULTS: Treatment of E7-expressing TC-1 tumor cells with 3-BrPA induced significantly higher in vitro cytotoxicity and resulted in upregulation of endoplasmic reticulum stress markers (CHOP and GRP78). More importantly, combination treatment of 3-BrPA and the CRT/E7 DNA vaccine led to improved antigen-specific CD8+ T cell immune responses as well as therapeutic antitumor effects in TC-1 tumor-bearing mice. CONCLUSIONS: Our data indicate that 3-BrPA can enhance therapeutic HPV vaccine potency in generating improved antigen-specific immune responses and antitumor effects. These findings have important implications for future clinical translation and provide novel strategies for the treatment of HPV-associated diseases.

Repositioning of the antipsychotic drug TFP for sepsis treatment.

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.

A novel TLR4 binding protein, 40S ribosomal protein S3, has potential utility as an adjuvant in a dendritic cell-based vaccine.

BACKGROUND: Dendritic cells (DCs) are professional antigen presenting cells (APCs), which can activate antigen-specific CD8+ T cell immunity, resulting in tumor clearance. Immature DCs are usually stimulated by various adjuvants through their immune receptors. Among them, Toll-like receptor 4 (TLR4) has an important role in activating DCs to cause their maturation. In fact, TLR4 is well-known to induce innate and adaptive immune responses against various external microbial or internal damage associated molecular patterns (DAMP). LPS is widely regarded as a strong stimulator of TLR4 signaling. However, LPS is inappropriate for use in humans since it is an endotoxin. Unfortunately, other TLR4 ligands such as HMGB1 or heat shock proteins have weak adjuvant effects. Therefore, there is a need to identify novel, biocompatible, strong, TLR4 ligands. METHODS: 40S ribosomal protein S3 (RPS3) was screened through pull-down assay using TLR4. BMDCs from wild type (WT) and TLR4 knock-out mice were treated by RPS3 to identify the activation and maturation of DCs. T cell generation including memory T cells, tumor prevention, and treatment experiments were performed with BMDCs based vaccination. Also, human DCs originated from patients were treated by RPS3 to confirm the activation and maturation of DCs. RESULTS: In this study, we identified 40S ribosomal protein S3 (RPS3) through a pull-down assay using a variety of human cancer cell-derived proteins that could bind to TLR4. RPS3 was released from tumor cells following treatment with an anticancer drug, and it was shown that the released RPS3 binds to TLR4. Recombinant RPS3 induced maturation and activation of DCs, and following pulsing with tumor specific antigens, these DCs could be used as a vaccine to significantly increase tumor specific CD8+IFN-γ+ T cells, and provide both tumor prevention and tumor treatment effects. The effect of RPS3 on DC maturation and its utility as a vaccine were shown to be dependent on TLR4 using TLR4 knockout mice. CONCLUSIONS: This study therefore proved that human cancer cell-derived RPS3, a novel TLR4 ligand, has great potential as an adjuvant in tumor-specific antigen DC-based vaccines.