Cancer immunology research最新文献

Interleukin 2 (IL-2) is a crucial cytokine in T-cell immunity, with a promising potential in cancer vaccines. However, therapeutic application of IL-2 is hampered by its short half-life and substantial toxicity. This study reports preclinical characterization of a mouse serum albumin-IL-2 fusion protein (Alb-IL2) encoded on nucleoside-modified RNA that is delivered via a nanoparticle formulation (Alb-IL2 RNA-NP) mediating prolonged cytokine availability. Alb-IL2 RNA-NP was combined with RNA-lipoplex (RNA-LPX) vaccines to evaluate its effect on the expansion of vaccine-induced antigen specific T-cell immunity. In mice dosed with Alb-IL2 RNA-NP, translated protein was shown to be systemically available up to 2 days, with an albumin-dependent preferred presence in the tumor and tumor-draining lymph node. Alb-IL2 RNA-NP administration prolonged serum availability of the cytokine compared with murine recombinant IL-2. In combination with RNA-LPX vaccines, Alb-IL2 RNA-NP administration highly increased the expansion of RNA-LPX vaccine-induced CD8+ T cells in the spleen and blood. The combination enhanced and sustained the fraction of IL-2 receptor (IL-2R) α-positive antigen-specific CD8+ T cells and ameliorated the functional capacity of the CD8+ T-cell population. Alb-IL2 RNA-NP strongly improved the antitumor activity and survival of concomitant RNA-LPX vaccination and PD-L1 blockade in a subcutaneous mouse tumor model. The favorable pharmacokinetic properties of Alb-IL2 RNA-NP render it an attractive modality for rationally designed combination immunotherapy. RNA vaccines that induce tumor-specific T-cell immunity for Alb-IL2 RNA-NP to further amplify are particularly attractive combination partners.

Cancer exploits different mechanisms to escape T-cell immunosurveillance, including overexpression of checkpoint ligands, secretion of immunosuppressive molecules, and aberrant glycosylation. Herein, we report that IFNγ, a potent immunomodulator secreted in the tumor microenvironment, can induce α2,6 hypersialylation in cancer cell lines derived from various histologies. We focused on Siglec-9, a receptor for sialic acid moieties, and demonstrated that the Siglec-9+ T-cell population displayed reduced effector function. We speculated that Siglec-9 in primary human T cells can act as a checkpoint molecule and demonstrated that knocking out Siglec-9 using a clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system enhanced the functionality of primary human T cells. Finally, we aimed to augment cancer-specific T-cell activity by taking advantage of tumor hypersialylation. Thus, we designed several Siglec-9-based chimeric switch receptors (CSR), which included an intracellular moiety derived from costimulatory molecules (CD28/41BB) and different hinge regions. In an antigen-specific context, T cells transduced with Siglec-9 CSRs demonstrated increased cytokine secretions and upregulation of activation markers. Moreover, T cells equipped with specific Siglec-9 CSRs mediated robust antitumor activity in a xenograft model of human tumors. Overall, this work sheds light on tumor evasion mechanisms mediated by sialylated residues and exemplifies an approach to improve engineered T cell-based cancer treatment. See related Spotlight by Abken, p. 1310.

Tumor-associated immune repression dampens the success of T-cell therapy for cancer by a plethora of inhibitory mechanisms including aberrant glycosylation. In this issue, Eisenberg and colleagues show that IFNγ induces hyper-sialylation of cancer cells and that this acts as the "checkpoint" through binding to the inhibitory molecule Siglec-9 on immune cells. A chimeric Siglec-9 "switch" receptor converts the suppressive signal into a stimulatory signal, thereby restoring T-cell responses in the tumor tissue, which has multiple implications for the use of adoptive cell therapy in cancer. See related article by Eisenberg et al., p. 1380 (3).

Natural killer (NK) cells are the main innate antitumor effector cells but their function is often constrained in the tumor microenvironment. It has been reported that the E3 ligase FBXO38 accelerates PD-1 degradation in tumor-infiltrating T cells to unleash their cytotoxic function. In this study, we found that the transcriptional levels of FBXO38 in intratumoral NK cells of patients with cancer and tumor-bearing mice were significantly lower than in peritumoral NK cells. Conditional knockout of FBXO38 in NK cells accelerated tumor growth and increased tumor metastasis. FBXO38 deficiency resulted in impaired proliferation and survival of tumor-infiltrating NK (TINK) cells. Mechanistically, FBXO38 deficiency enhanced TGF-β signaling, including elevating expression of Smad2 and Smad3, which suppressed expression of the transcription factor Eomes and further reduced expression of surface IL15Rβ and IL15Rγc on NK cells. Consequently, FBXO38 deficiency led to TINK cell hyporesponsiveness to IL15. Consistent with these observations, FBXO38 mRNA expression was positively correlated with the proliferation of TINK cells in multiple human tumors. To study the therapeutic potential of FBXO38, mice bearing human tumors were treated with FBXO38 overexpressed human primary NK cells and showed a significant reduction in tumor size and prolonged survival. In conclusion, our results suggest that FBXO38 sustains NK-cell expansion and survival to promote antitumor immunity and have potential therapeutic implications as they suggest FBXO38 could be harnessed to enhance NK cell-based cancer immunotherapy.

Intratumoral hypoxia not only promotes angiogenesis and invasiveness of cancer cells but also creates an immunosuppressive microenvironment that facilitates tumor progression. However, the mechanisms by which hypoxic tumor cells disseminate immunosuppressive signals remain unclear. In this study, we demonstrate that a hypoxia-induced long noncoding RNA HIF1A Antisense RNA 2 (HIF1A-AS2) is upregulated in hypoxic tumor cells and hypoxic tumor-derived exosomes in head and neck squamous cell carcinoma (HNSCC). Hypoxia-inducible factor 1 alpha (HIF1α) was found to directly bind to the regulatory region of HIF1A-AS2 to enhance its expression. HIF1A-AS2 reduced the protein stability of major histocompatibility complex class I (MHC-I) by promoting the interaction between the autophagy cargo receptor neighbor of BRCA1 gene 1 (NBR1) protein and MHC-I, thereby increasing the autophagic degradation of MHC-I. In HNSCC samples, the expression of HIF1A-AS2 was found to correlate with hypoxic signatures and advanced clinical stages. Patients with high HIF1α and low HLA-ABC expression showed reduced infiltration of CD8+ T cells. These findings define a mechanism of hypoxia-mediated immune evasion in HNSCC through downregulation of antigen-presenting machinery via intracellular or externalized hypoxia-induced long noncoding RNA.

Ovarian cancers and microsatellite stable (MSS) colorectal cancers (CRC) are insensitive to anti-PD1 immunotherapy, and new immunotherapeutic approaches are needed. Preclinical data suggests a relationship between immunotherapy resistance and elevated angiopoietin 2 levels. We performed a phase 1 dose-escalation study of pembrolizumab and the angiopoietin 1/2 inhibitor trebananib (NCT03239145). This multicenter trial enrolled patients with metastatic ovarian cancer or MSS CRC. Trebananib was administered intravenously weekly for 12 weeks with 200 mg intravenous pembrolizumab every 3 weeks. The toxicity profile of this combination was manageable, and the protocol-defined highest dose level (trebananib 30 mg/kg weekly plus pembrolizumab 200 mg every 3 weeks) was declared the maximum tolerated dose. The objective response rate for all patients was 7.3% (90% confidence interval: 2.5-15.9%). Three patients with MSS CRC had durable responses for ≥3 years. One responding patient's CRC harbored a POLE mutation. The other two responding patients had left-sided CRCs with no baseline liver metastases, and genomic analysis revealed that they both had KRAS wild-type, ERBB2 amplified tumors. After development of acquired resistance, biopsy of one patient's KRAS wild-type, ERBB2 amplified tumor showed a substantial decline in tumor-associated T cells and an increase in immunosuppressive intratumoral macrophages. Future studies are needed to carefully assess whether clinicogenomic features, such as lack of liver metastases, ERBB2 amplification, and left-sided tumors, can predict increased sensitivity to PD1 immunotherapy combinations.

Radiotherapy (RT) triggers an immune response that contributes to anti-tumor effects. Induction of interferon beta (IFN-β) is a key event in this immunogenicity of RT. We have previously shown that TRIM33, a chromatin reader, restrains IFN-β expression in Toll-like receptor-activated myeloid cells. Here, we explored whether deleting Trim33 in myeloid cells might improve the radio-induced immune response, and subsequent efficiency of RT. We first established that Trim33-/- bone marrow-derived macrophages showed increased expression of IFN-β in response to direct irradiation, or to treatment with irradiated cancer cells, further supporting our hypothesis. We then tested the efficiency of a single dose RT in three subcutaneous and one orthotopic tumor models. In all situations, myeloid deletion of Trim33 led to a significantly improved response after RT, leading to a complete and durable response in most of the treated mice bearing orthotopic oral tumors. This effect required the IFN-I pathway, and the presence of CD8+ T lymphocytes, but not NK cells. In addition, cured mice were capable of rejecting a secondary tumor challenge, demonstrating an in situ vaccination effect. We conclude that deleting Trim33 in myeloid cells improves RT efficiency, through a mechanism involving the IFN-I pathway and the immune response. Our work suggests that myeloid Trim33 is a host factor affecting the tumor response to RT, thus representing a new potential therapeutic target for modifying RT responses.

Despite recent advances in immunotherapy with immune checkpoint inhibitors (ICI), many patients with non-small cell lung cancer (NSCLC) fail to respond or develop resistance after an initial response. In situ vaccination (ISV) with engineered viruses has emerged as a promising antigen-agnostic strategy that can both condition the tumor microenvironment (TME) and augment anti-tumor T cell responses to overcome immune resistance. We engineered a live attenuated viral vaccine, Hyper-Interferon Sensitive virus (HIS), by conducting a genome-wide functional screening and introducing eight interferon (IFN)-sensitive mutations in the influenza genome. Compared to wild-type (WT) influenza, HIS replication was attenuated in immunocompetent hosts, enhancing its potential as a safe option for cancer therapy. HIS ISV elicited robust yet transient type I IFN responses in murine NSCLCs, leading to an enrichment of polyfunctional effector Th1 CD4 and cytotoxic CD8 T cells into the tumor. HIS ISV demonstrated enhanced anti-tumor efficacy compared to WT in multiple syngeneic murine models of NSCLC with distinct driver mutations and varying mutational burden. This efficacy was dependent on host type 1 IFN responses and T lymphocytes. HIS ISV overcame resistance to anti-PD-1 in LKB-1 deficient murine NSCLC, resulting in improved overall survival and enduring systemic tumor-specific immunity. These studies provide compelling evidence to support further clinical evaluation of HIS as a novel 'off-the-shelf' ISV strategy for patients with NSCLC refractory to ICI.

Vγ9Vδ2 T cells are potent but elusive cytotoxic effectors. Butyrophilin subfamily 2 member A1 (BTN2A1) is a surface protein that has recently been shown to bind the Vγ9 chain of the γδ T-cell receptor (TCR) but its precise role in modulating Vγ9Vδ2 T-cell functions remains unknown. Here, we show that 107G3B5, a monoclonal BTN2A1 agonist antibody, was able to significantly enhance Vγ9Vδ2 T-cell functions against hematological or solid cell lines and against primary cells from adult acute lymphoblastic leukemia patients. New computer vision strategies applied to holotomographic microscopy videos showed that 107G3B5 enhanced the interaction between Vγ9Vδ2 T cells and target cells in a quantitative and qualitative manner. In addition, we found that Vγ9Vδ2 T cells activated by 107G3B5 induced caspase 3/7 activation in tumor cells, thereby triggering tumor cell death by pyroptosis. Together, these data demonstrate that targeting BTN2A1 with 107G3B5 enhances the Vγ9Vδ2 T-cell antitumor response by triggering the pyroptosis-induced immunogenic cell death. These new pyroptosis-based therapies have great potential to stimulate the immune system to fight cancer, especially "cold" tumors.