Novel Strategy For Cancer Immunotherapy Research Articles

Abstract 2469: PROTAC mediated NR4A1 degradation as a novel strategy for cancer immunotherapy

Abstract An effective cancer therapy requires both killing cancer cells and targeting tumor-promoting pathways or cell populations within the tumor microenvironment (TME). We purposely search for molecules that are critical for multiple cell types in the TME and identified nuclear receptor subfamily 4 group A member 1 (NR4A1) as one such molecule. NR4A1 has been shown to promote the aggressiveness of cancer cells and maintain the immune suppressive TME. Using genetic and pharmacological approaches, we establish NR4A1 as a valid therapeutic target for cancer therapy. Importantly, we have developed the first-of-its kind proteolysis-targeting chimera (PROTAC, named NR-V04) against NR4A1. NR-V04 effectively degrades NR4A1 within hours of treatment in vitro and sustains for at least 4 days in vivo, exhibiting long-lasting NR4A1-degradation in tumors and an excellent safety profile. NR-V04 leads to robust tumor inhibition and sometimes eradication of established melanoma tumors. At the mechanistic level, we have identified an unexpected novel mechanism via significant induction of tumor-infiltrating (TI) B cells as well as an inhibition of monocytic myeloid derived suppressor cells (m-MDSC), two clinically relevant immune cell populations in human melanomas. Overall, NR-V04-mediated NR4A1 degradation holds promise for enhancing anti-cancer immune responses and offers a new avenue for treating various types of cancer such as melanoma. Citation Format: Lei Wang, Yufeng Xiao, Yuewan Luo, Rohan Master, Jiao Mo, Myung-Chul Kim, Yi Liu, Chandra Maharjan, Urvi Patel, Xiangming Li, Donald Shaffer, Guertin Kevin, Haoyang Zhuang, Emily Moser, Keiran Smalley, Daohong Zhou, Guangrong Zheng, Weizhou Zhang. PROTAC mediated NR4A1 degradation as a novel strategy for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2469.

Abstract 718: CCR8 antibody drug conjugates: Targeting regulatory T cells for tumor sensitization

Abstract Background: Regulatory T (Treg) cells in the tumor microenvironment have an immune suppressive function, and their presence is associated with poor prognosis. Depletion of Treg cells may be a mechanism to sensitize tumors and represents a novel strategy for cancer immunotherapy. High expression of chemokine receptor CCR8 has been found in Treg cells in microenvironments of numerous tumors but not on Treg cells in systemic lymphoid tissues. The ability to selectively kill Treg cells in tumor environments may provide an opportunity for therapy that leaves Treg function intact elsewhere in the body where they normally mediate tolerance to self-antigen. Methods: We sought to identify CCR8 antibodies for therapeutics and designed an antibody discovery strategy to address the challenges of this target. CCR8 is a member of the G protein-coupled receptor (GPCR) family. Like many GPCRs, CCR8 is a valuable therapeutic antibody target but challenging to access due to its poor expression, membrane-dependent structure, and poor immunogenicity due to sequence conservation. We developed an antibody discovery platform (MPS) that specifically addresses each of these challenges through use of advanced immunization techniques and evolutionarily divergent host species (chickens) for robust immune responses against conserved targets. We extensively engineered CCR8 antigen to enable high expression for immunization. When sufficient antibody diversity was not obtained using our standard immunization techniques, we developed mRNA immunization techniques for this program. Antibody binding was measured using flow cytometry on transfected cells and human Treg cells. The ability of antibodies to inhibit CCR8 function was measured using intracellular calcium influx assays. Antibody internalization was measured using dye uptake assays and flow cytometry. Antibodies were conjugated with cytotoxic payloads and tested for the ability to mediate killing. Results: Using these approaches, we identified a panel of high-affinity antibodies that bound in the nanomolar or subnanomolar range with high specificity, and we selected a lead molecule to progress. We will present data from our antibody discovery campaign including mRNA immunization, binding profiles, GPCR functional data, receptor-mediated internalization, and the ability of antibody-drug conjugates (ADC) to kill CCR8+ cells, including human Treg cells, in vitro. Conclusion: Treg cells are a primary driver of the immunosuppressive microenvironment in many solid tumors. Targeting immune-suppressive CCR8+ Treg cells using ADC has potential to expand the treatment of solid tumors Citation Format: Lewis J. Stafford, Hayley Roth, Sarah Campbell, Samantha Brady, Valerie Fiers, FeiFan Yu, Andrew Tsourkas, Riley Payne, Meghan Pitts, Kyle Guldner, Tim Phillips, Breanna Tyrell, Colleen Ulke, Allison Snyder, Marianne Assogba, Holden Ohl, Ileine Sanchez, Benjamin Doranz, Joseph Rucker, Ross Chambers. CCR8 antibody drug conjugates: Targeting regulatory T cells for tumor sensitization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 718.

Dual-Responsive Supramolecular Polymeric Nanomedicine for Self-Cascade Amplified Cancer Immunotherapy.

Insufficient tumor immunogenicity and immune escape from tumors remain common problems in all tumor immunotherapies. Recent studies have shown that pyroptosis, a form of programmed cell death that is accompanied by immune checkpoint inhibitors, can induce effective immunogenic cell death and long-term immune activation. Therapeutic strategies to jointly induce pyroptosis and reverse immunosuppressive tumor microenvironments are promising for cancer immunotherapy. In this regard, a dual-responsive supramolecular polymeric nanomedicine (NCSNPs) to self-cascade amplify the benefits of cancer immunotherapy is designed. The NCSNPs are formulated by β-cyclodextrin coupling nitric oxide (NO) donor, a pyroptosis activator, and NLG919, an indoleamine 2,3-dioxygenase (IDO) inhibitor, and self-assembled through host-guest molecular recognition and hydrophobic interaction to obtain nanoparticles. NCSNPs possess excellent tumor accumulation and bioavailability attributed to ingenious supramolecular engineering. The study not only confirms the occurrence of NO-triggered pyroptosis in tumors for the first time but also reverses the immunosuppressive microenvironment in tumor sites via an IDO inhibitor by enhancing the infiltration of cytotoxic T lymphocytes, to achieve remarkable inhibition of tumor proliferation. Thus, this study provides a novel strategy for cancer immunotherapy.

PROTAC-mediated NR4A1 degradation as a novel strategy for cancer immunotherapy.

An effective cancer therapy requires killing cancer cells and targeting the tumor microenvironment (TME). Searching for molecules critical for multiple cell types in the TME, we identified NR4A1 as one such molecule that can maintain the immune suppressive TME. Here, we establish NR4A1 as a valid target for cancer immunotherapy and describe a first-of-its-kind proteolysis-targeting chimera (PROTAC, named NR-V04) against NR4A1. NR-V04 degrades NR4A1 within hours in vitro and exhibits long-lasting NR4A1 degradation in tumors with an excellent safety profile. NR-V04 inhibits and frequently eradicates established tumors. At the mechanistic level, NR-V04 induces the tumor-infiltrating (TI) B cells and effector memory CD8+ T (Tem) cells and reduces monocytic myeloid-derived suppressor cells (m-MDSC), all of which are known to be clinically relevant immune cell populations in human melanomas. Overall, NR-V04-mediated NR4A1 degradation holds promise for enhancing anticancer immune responses and offers a new avenue for treating various types of cancers such as melanoma.

C/EBPα mediates the maturation and antitumor functions of macrophages in human hepatocellular carcinoma

Recent studies have suggested that therapeutic upregulation of CCAAT/enhancer binding protein α (C/EBPα) prevents hepatocellular carcinoma (HCC) progression. However, the mechanisms underlying this outcome are not fully understood. In this study, we investigated the expression and functional roles of C/EBPα in human HCC, with a focus on monocytes/macrophages (Mφs). Paraffin-embedded tissues were used to visualize C/EBPα expression and analyze the prognostic value of C/EBPα+ monocytes/Mφs in HCC patients. The underlying regulatory mechanisms were examined using human monocyte-derived Mφs. The results showed that the expression of C/EBPα on monocytes/Mφs was significantly decreased in intra-tumor tissues compared to the corresponding peri-tumor tissues. C/EBPα+ monocytes/Mφs displayed well-differentiation and antitumor capacities, and the accumulation of these cells in tissue was associated with antitumor immune responses and predicted longer overall survival (OS) of HCC patients. Mechanistic studies demonstrated that C/EBPα was required for Mφ maturation and HLA-DR, CD169 and CD86 expression, which initiates antitumor cytotoxic T-cell responses; however, these effects were inhibited by monocyte autocrine IL-6- and IL-1β-induced suppression of mTOR1 signaling. Reprogramming Mφs via the upregulation of C/EBPα may provide a novel strategy for cancer immunotherapy in patients with HCC.

Tetrahydrobiopterin inhibitor-based antioxidant metabolic strategy for enhanced cancer ferroptosis-immunotherapy

The induction of immunogenic ferroptosis in cancer cell is limited by the complex and delicate antioxidant system in the organism. Synergistic induction of oxidative damage and inhibition of the defensive redox system in tumor cells is critical to promote lethal accumulation of lipid peroxides and activate immunogenic death (ICD). To address this challenge, we present a multifunctional and dual-responsive layered double hydroxide (LDH) nanosheet to enhance immunogenic ferroptosis. The MTX-LDH@MnO2 nanoplatform is constructed by intercalating methotrexate (MTX) into LDH interlayers and electrostatically absorbing biomineralized ovalbumin (OVA)-MnO2 onto the LDH surface. Specifically, the released Mn2+ from the incorporated MnO2 triggers a Fenton-like reaction, leading to reactive oxygen species (ROS) accumulation, while the depletion of reduced glutathione (GSH) further intensifies oxidative stress, resulting in the induction of ferroptosis. MTX is released in response to the acidic environment of tumor cells and inhibits the regeneration of tetrahydrobiopterin (BH4), modulating the GTP cyclic hydrolase 1 (GCH1)/BH4 axis. MTX disrupts the antioxidant metabolic activity regulated by GCH1/BH4 axis and inhibits ROS consumption, further boosting the ferroptosis effect, which promoted the release of damage-associated molecular patterns (DAMPs) and triggered ICD in the tumor. This activation subsequently leads to significant antitumor immune reactions, including DCs maturation, infiltration of CD4+/CD8+ T cells and cytokines release. The redox-controllable nanoplatform demonstrates promising anticancer efficacy in a mouse breast model providing a novel strategy for cancer immunotherapy.

Inhibition of CK2/ING4 Pathway Facilitates Non-Small Cell Lung Cancer Immunotherapy.

Immune cells can protect against tumor progression by killing cancer cells, while aberrant expression of the immune checkpoint protein PD-L1 (programmed death ligand 1) in cancer cells facilitates tumor immune escape and inhibits anti-tumor immunotherapy. As a serine/threonine kinase, CK2 (casein kinase 2) regulates tumor progression by multiple pathways, while it is still unclear the effect of CK2 on tumor immune escape. Here it is found that ING4 induced PD-L1 autophagic degradation and inhibites non-small cell lung cancer (NSCLC) immune escape by increasing T cell activity. However, clinical analysis suggests that high expression of CK2 correlates with low ING4 protein level in NSCLC. Further analysis shows that CK2 induce ING4-S150 phosphorylation leading to ING4 ubiquitination and degradation by JFK ubiquitin ligase. In contrast, CK2 gene knockout increases ING4 protein stability and T cell activity, subsequently, inhibites NSCLC immune escape. Furthermore, the combined CK2 inhibitor with PD-1 antibody effectively enhances antitumor immunotherapy. These findings provide a novel strategy for cancer immunotherapy.

Abstract 6391: Development of a novel strategy for cancer immunotherapy based on tumor immunogenicity improvement by HLA-drug interaction

Abstract [Purpose] Tumors with low T cell infiltrates (poor immunogenicity) display lower probability of clinical response to immune checkpoint inhibitors. To achieve higher immunotherapy efficacy, it is imperative to establish a novel strategy for improving immunogenicity. Abacavir (ABC), an anti-HIV drug, binds to the specific allele of human leukocyte antigen (HLA-B*57:01) and activate CD8+ T cells by presenting altered abnormal peptides. In this study, we considered the immune interaction between ABC and HLA-B*57:01 improving immunogenicity in poorly immunogenic tumors leading to a potent anti-cancer effect. [Methods] Mice were inoculated subcutaneously with tumor cells into the right flanks and interperitoneally treated with either ABC 5 mg or vehicle (water) for consecutive 9 days (B16F10) or 13 days (3LL) after tumor inoculation. Each tumor size was measured using vernier calipers on every 2 days. Activation, proliferation, and IFN-γ secretion of tumor infiltrating CD8+ T cells were analyzed by FACS. [Results and Discussion] ABC treatment showed significant tumor growth inhibition associated with CD8+ T cell infiltration into tumor in mice inoculated with HLA-B*57:01 expressing B16F10 melanoma or Lewis lung carcinoma (3LL) cells, but neither in HLA-B*57:03 (negative allele)-expressing nor control tumors inoculated mice. Moreover, the tumor infiltrating CD8+ T cell were immune-activated and proliferated, with secreting IFN-γ. In contrast, ABC-induced anti-tumor effect was abrogated in CD8+ T cell-depleted mice, IFN-γ KO mice, and CXCR3-blocked mice. The combination therapy with anti-PD-1 antibody treatment induced better inhibition of tumor growth than ABC monotherapy in HLA-B*57:01 expressing B16F10 inoculated mice. These results suggested that ABC/HLA-B*57:01 interaction could improve tumor immunogenicity associated with CD8+ T cell-mediated anti-tumor effect in poorly immunogenic tumors. This finding lays a foundation to develop a novel drug-induced cancer immunotherapy targeting immune resistant tumors. Citation Format: Takeshi Susukida, So-ichiro Sasaki, Tomohiro Shirayanagi, Shigeki Aoki, Kousei Ito, Yoshihiro Hayakawa. Development of a novel strategy for cancer immunotherapy based on tumor immunogenicity improvement by HLA-drug interaction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6391.

Abstract 1543: Discovery of CCR8 antibodies targeting regulatory T cells to enable tumor sensitization

Abstract Regulatory T (Treg) cells in the tumor microenvironment have an immune suppressive function, and their presence is associated with poor prognosis. Depletion of Treg cells may be a mechanism to sensitize tumors and represents a novel strategy for cancer immunotherapy. High expression of chemokine receptor CCR8 has been found in Treg cells in microenvironments of numerous tumors but not on Treg cells in systemic lymphoid tissues. The ability to selectively kill Treg cells in tumor environments may provide an opportunity for therapy that leaves Treg function intact elsewhere in the body where they normally mediate tolerance to self-antigen. We sought to identify CCR8 antibodies for therapeutics and designed an antibody discovery strategy to address the challenges of this target. CCR8 is a member of the G protein-coupled receptor (GPCR) family. Like many GPCRs, CCR8 is a valuable therapeutic target but is challenging to target using antibodies due to its poor expression, membrane-dependent structure, small extracellular regions, and poor immunogenicity due to sequence conservation. We developed an antibody discovery platform (MPS) that specifically addresses each of these challenges through use of advanced immunization techniques and evolutionarily divergent host species (chickens) for robust immune responses against conserved targets. We extensively engineered CCR8 antigen to enable high expression for immunization. When sufficient antibody diversity using our standard immunization techniques was not obtained, we developed mRNA immunization techniques for this program. Using these approaches, we were able to identify a panel of high-affinity antibodies that bind in the nanomolar or subnanomolar range with high specificity. We will present data from our antibody discovery campaign including mRNA immunization, binding profiles, GPCR functional data, and the ability of the antibodies to kill Treg cells in vitro using both ADCC and antibody-drug conjugates (ADC). Citation Format: Brad Screnci, Hayley Roth, Sarah Campbell, David Tucker, Colleen Fenn-Ulke, Erin Rosenberg, Meghan Pitts, Naomi Saint-Jean, Jawhara Karam, Paige Murphy, Daniela Reyes, Janae Latta, Kyle Guldner, Samantha Gilman, Tim Phillips, L. Joe Stafford, Breanna Tyrell, Kristen Shema, Chidananda Sulli, Nick Molino, Allison Snyder, Marianne Assogba, Janvi Shah, McKayla Zimmerman, Trevor Barnes, Riley Payne, Alyssa Cunningham, Elisabeth Charrier, Holden Ohl, Kyle Doolan, Ileine Sanchez, Joseph B. Rucker, Ross Chambers, Benjamin Doranz. Discovery of CCR8 antibodies targeting regulatory T cells to enable tumor sensitization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1543.

The role of gene expression of CD47 in colorectal cancer (CRC).

240 Background: CD47 belongs to the immunoglobulin superfamily and is overexpressed in many tumor types. CD47 plays an important role in suppressing phagocytosis through binding to transmembrane protein SIRP-alpha on macrophages. Targeting CD47 is a novel strategy for cancer immunotherapy and is being evaluated in ongoing clinical trials. However, molecular characteristics of CD47-overexpressed colorectal cancer (CRC) are largely unknown. Methods: We retrospectively reviewed CRC patient samples (n = 14786) submitted to a commercial CLIA-certified laboratory (Caris Life Sciences, Phoenix AZ). Next-generation sequencing of DNA and RNA (whole-transcriptome sequencing) and immunohistochemistry were performed. Correlation of CD47 expression with danger-associated molecular pattern (DAMP)-related genes ( HMGB1, CALR, ANXA1, HSP90AA1, HSPA1A, and CXCL10) expressions was tested. DAMP signature calculated as composite z-score of the DAMP related genes was compared between CD47-high and -low patients classified according to the median level of CD47 expression. Distributions of KRAS and BRAF mutations, consensus molecular subtype (CMS), and signatures of oncogenic signaling pathways were compared between CD47-high and -low patients. In addition, overall survival (OS) was compared between CD47-high and -low patients available for survival data. Results: CD47 expression level was significantly higher in metastatic compared to primary lesions (1.07-fold, q < 0.05) and microsatellite instability high tumors compared to microsatellite stable tumors (1.15-fold, q < 0.05). CD47 expression was positively correlated with DAMP genes expression except for HSPA1A, and the DAMP signature (median score [MS]: 2.66 vs -2.29, q < 0.05) was significantly increased in CD47-high patients. KRAS mutations were less prevalent (45.87% vs 50.05%) and CMS1(17.72% vs 14.42%) and CMS4 (40.33% vs 27.28%) were more prevalent in CD47-high patients, while no difference was observed in the prevalence of BRAF mutations between CD47-high and -low patients. Signatures of EMT (MS:2.91 vs -3.19), TGF-beta (MS:3.72 vs -3.52), angiogenesis (MS:2.95 vs -2.78), MAPK (MS:4.99 vs -4.12), PI3K (MS:2.41 vs -2.03), and immune-related signaling pathways (MS:1.20 vs -2.51) were significantly enriched in CD47-high patients (all q < 0.05). CD47-high patients (n = 4873) showed significantly worse OS than CD47-low patients (n = 4898) (median OS, 32.4 vs 37.6 months; hazard ratio = 1.158, p< 0.01). Conclusions: Highly CD47-expressed CRC harbored activation of DAMPs and oncogenic signaling pathways that linked to aberrant tumor microenvironment and worse prognosis. Our results support intensive treatment strategies using CD47 inhibitors combined with cytotoxic agents and molecular targeted agents (such as anti-VEGF agents) in CD47-overexpressed CRC.

Abstract 2064: Targeting Cblb-Notch1 axis as a novel strategy for cancer immunotherapy

Abstract Background: Tumor-induced immunosuppression is a way in which cancers evade the host immune response. In recent years, a great effort has been made in designing immunotherapies that can boost the immune system response against cancer. However, not all tumors respond to these therapies. Therefore, there remains an unmet need for immunotherapies that are able to circumvent tumor-induced immunosuppression. Adenosine is an immunosuppressive metabolite which is overproduced in hypoxic tumor microenvironments and dampens T-cell anti-tumor immune responses. Adenosine A2A receptor (A2AR) activation was shown to downregulate Notch1, a key regulator of T-cell functions, in CD8+ T-cells, leading to immunosuppression. Notch1 signaling appears to protect T-cells against immunosuppressive signals, as Notch1 overexpressing T-cells were shown to be resistant to tumor-induced immunosuppression mediated by myeloid-derived suppressor cells (MDSC), as well as adenosine. We hypothesize that rescuing Notch1 from downregulation will make T-cells resistant to tumor-induced immunosuppression. We applied several functional assays in primary CD8+ T-cells and tumor-derived organoids to study how Notch1 is regulated by A2AR and explore strategies to target this pathway for cancer immunotherapy. Results: Our results indicate that the ubiquitin ligase Cbl-b, a negative regulator of T-cell functions, is responsible for the ubiquitination and degradation of Notch1 in CD8+ T-cells. A2AR signaling leads to Notch1 downregulation by promoting Cbl-b-mediated Notch1 degradation. Inhibition of Cbl-b using small molecule compounds restores Notch1 and T-cell functions in CD8+ T-cells in the presence of adenosine, making them resistant to A2AR-mediated immunosuppression. Cbl-b inhibitors show anti-tumor activity in tumor-derived organoids from pre-clinical models and enhance immune-checkpoint immunotherapy, by promoting T-cells anti-cancer responses. Conclusions: Our work suggests that promoting Notch1 signaling by blocking Cbl-b-mediated degradation results in increased T-cell responses and resistance to immunosuppression. Targeting Cbl-b-Notch1 axis represents a promising novel strategy to boost anti-cancer T-cell responses. Citation Format: Giulia Monticone, Fred Csibi, Silvana Leit, Jermaine E. Austin, Deniz A. Ucar, Fokhrul M. Hossain, Samarpan Majumder, Barbara A. Osborne, Christine Loh, Lucio Miele. Targeting Cblb-Notch1 axis as a novel strategy for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2064.

Cancer immunotherapy by NC410, a LAIR-2 Fc protein blocking human LAIR-collagen interaction.

Collagens are a primary component of the extracellular matrix and are functional ligands for the inhibitory immune receptor leukocyte-associated immunoglobulin-like receptor (LAIR)-1. LAIR-2 is a secreted protein that can act as a decoy receptor by binding collagen with higher affinity than LAIR-1. We propose that collagens promote immune evasion by interacting with LAIR-1 expressed on immune cells, and that LAIR-2 releases LAIR-1-mediated immune suppression. Analysis of public human datasets shows that collagens, LAIR-1 and LAIR-2 have unique and overlapping associations with survival in certain tumors. We designed a dimeric LAIR-2 with a functional IgG1 Fc tail, NC410, and showed that NC410 increases human T cell expansion and effector function in vivo in a mouse xenogeneic-graft versus-host disease model. In humanized mouse tumor models, NC410 reduces tumor growth that is dependent on T cells. Immunohistochemical analysis of human tumors shows that NC410 binds to collagen-rich areas where LAIR-1+ immune cells are localized. Our findings show that NC410 might be a novel strategy for cancer immunotherapy for immune-excluded tumors.

Potential New Cancer Immunotherapy: Anti-CD47-SIRPα Antibodies.

CD47 belongs to immunoglobulin superfamily and is widely expressed on the surface of cell membrane, while another transmembrane protein SIRPα is restricted to the surface of macrophages, dendritic cells, and nerve cells. As a cell surface receptor and ligand, respectively, CD47 and SIRPα interact to regulate cell migration and phagocytic activity, and maintain immune homeostasis. In recent years, studies have found that immunoglobulin superfamily CD47 is overexpressed widely across tumor types, and CD47 plays an important role in suppressing phagocytes activity through binding to the transmembrane protein SIRPα in phagocytic cells. Therefore, targeting CD47 may be a novel strategy for cancer immunotherapy, and a variety of anti-CD47 antibodies have appeared, such as humanized 5F9 antibody, B6H12 antibody, ZF1 antibody, and so on. This review mainly describes the research history of CD47-SIRPα and focuses on macrophage-mediated CD47-SIRPα immunotherapy of tumors.

Deleting key autophagy elongation proteins induces acquirement of tumor-associated phenotypes via ISG15.

Autophagy is a cellular catabolic process that maintains intracellular homeostasis using lysosomal degradation systems. We demonstrate that inhibiting autophagy by depleting essential autophagy elongation proteins, Atg5 or Atg7, induces ISG15 expression through STING-mediated cytosolic dsDNA response. Genome stability is impaired in ATG5- or ATG7-depleted cells, and thus, double-strand breakages of DNA increase and cytosolic dsDNA accumulates. Accumulated cytosolic dsDNA induces the STING pathway to activate type I IFN signals which induce STAT1 activity and downregulate ATF3. When depletion of ATG5 or ATG7 inhibits autophagy, ATF3 is downregulated and STAT1 is upregulated. Furthermore, inhibiting autophagy induces ISG15 expression through STAT1 activation, which promotes acquisition of tumor-associated phenotypes such as migration, invasion, and proliferation. In conclusion, it appears that via the STING-mediated cytosolic dsDNA response, the STAT1-ISG15 axis mediates the relationship between autophagy and the immune system in relation to tumor progression. Moreover, combined with autophagy control, regulating ISG15 expression could be a novel strategy for cancer immunotherapy.

Present and future of cancer immunotherapy: A tumor microenvironmental perspective.

Modulation of the tumor microenvironment is becoming an increasingly popular research topic in the field of immunotherapy, and studies regarding immune checkpoint blockades and cancer immunotherapy have pushed cancer immunotherapy to a climax. Simultaneously, the manipulation of the immune regulatory pathway can create an effective immunotherapy strategy; however, the tumor microenvironment serves an important role in suppressing the antitumor immunity by its significant heterogeneity. A number of patients with cancer do not have a good response to monotherapy approaches; therefore, combination strategies are required to achieve optimal therapeutic benefits. Targeting the tumor microenvironment may provide a novel strategy for immunotherapy, break down the resistance of conventional cancer therapy and produce the foundation for personalized precision medicine. The present review summarized the research regarding cancer immunotherapy from the perspective of how the tumor microenvironment affects the immune response, with the aim of proposing a novel strategy for cancer immunotherapy and combination therapy.

Helios expression in regulatory T cells promotes immunosuppression, angiogenesis and the growth of leukemia cells in pediatric acute lymphoblastic leukemia

Regulatory T cells (Tregs) characterized by the transcription factor forkhead box P3 (FoxP3) are crucial for maintaining immune tolerance and preventing autoimmunity. However, FoxP3 does not function alone and Helios is considered a potential candidate for defining Treg subsets. In this study, we investigated the expression and function of Helios for identifying Tregs in childhood precursor B-cell acute lymphoblastic leukemia (pre-B ALL). Our results demonstrated that patients with pre-B ALL had a higher percentage of Helios+ FoxP3+ CD4+ Tregs. And there was a positive correlation between the expression of Helios and the suppressive function of Tregs, the risk gradation of ALL. Helios in combination with CD4 and FoxP3 may be an effective way to detect functional Tregs in pre-B ALL by promoting the secretion of transforming growth factor (TGF)-β1. Furthermore, Helios+ Tregs could regulate angiogenesis in the BM niche of pre-B ALL via the VEGFA/VEGFR2 pathway. We also found Helios+ Tregs decreased apoptosis rate of nalm-6 cells by up-regulating the expression of anti-apoptosis protein Bcl-2. In summary, these data strongly imply the physiological importance of Helios expression in Tregs, and suggest that the manipulation of Helios may serve as a novel strategy for cancer immunotherapy.

Generation and Functional In Vitro Analysis of Semliki Forest Virus Vectors Encoding TNF-α and IFN-γ.

Cytokine gene delivery by viral vectors is a promising novel strategy for cancer immunotherapy. Semliki Forest virus (SFV) has many advantages as a delivery vector, including the ability to (i) induce p53-independent killing of tumor cells via apoptosis, (ii) elicit a type-I interferon (IFN) response, and (iii) express high levels of the transgene. SFV vectors encoding cytokines such as interleukin (IL)-12 have shown promising therapeutic responses in experimental tumor models. Here, we developed two new recombinant SFV vectors encoding either murine tumor necrosis factor-α (TNF-α) or murine interferon-γ (IFN-γ), two cytokines with documented immunostimulatory and antitumor activity. The SFV vector showed high infection rate and cytotoxicity in mouse and human lung carcinoma cells in vitro. By contrast, mouse and human macrophages were resistant to infection with SFV. The recombinant SFV vectors directly inhibited mouse lung carcinoma cell growth in vitro, while exploiting the cancer cells for production of SFV vector-encoded cytokines. The functionality of SFV vector-derived TNF-α was confirmed through successful induction of cell death in TNF-α-sensitive fibroblasts in a concentration-dependent manner. SFV vector-derived IFN-γ activated macrophages toward a tumoricidal phenotype leading to suppressed Lewis lung carcinoma cell growth in vitro in a concentration-dependent manner. The ability of SFV to provide functional cytokines and infect tumor cells but not macrophages suggests that SFV may be very useful for cancer immunotherapy employing tumor-infiltrating macrophages.

Anticancer Molecules in Brain: Implication for Novel Strategy for Cancer Immunotherapy.

Anticancer Molecules in Brain: Implication for Novel Strategy for Cancer Immunotherapy.

Iron, inflammation and invasion of cancer cells.

Chronic inflammation is associated with the metastasis of tumor cells evolving from a benign tumor to disseminating cancer. Such a metastatic progression is fostered by the angiogenesis propelled by various mediators interacting at the site of tumor growth. Angiogenesis causes two major changes that are assisted by altered glycosylation and neo-antigen presentation by the cancer cells. The angiogenesis-promoted pathological changes include enhanced inflammation and degradation of tissue matrices releasing tumor cells from the site of its origin. The degraded tumor cells release the neo-antigens resulting from altered glycosylation. Presentation of neo-antigens to T cells escalates metastasis and inflammation. Inflammasome activation and inflammation in several infections are regulated by iron. Based on the discrete reports, we propose a link between iron, inflammation, angiogenesis and tumor growth. Knowing the link better may help us formulate a novel strategy for cancer immunotherapy.

Cloning and expansion of antigen-specific T cells using iPSC technology: A novel strategy for cancer immunotherapy

Cloning and expansion of antigen-specific T cells using iPSC technology: A novel strategy for cancer immunotherapy