Immunotherapeutic Interventions Research Articles

Abstract P065: Effects of targeted radiotherapy on tumor immune landscape in diverse murine tumor models

Abstract Radiotherapy (RT) has traditionally been seen as a means to induce targeted tumor cell death, and more than 50% of all cancer patients receive RT. RT is also known to induce immune cell activation, and the advent of immunotherapeutic treatments such as checkpoint inhibition has sparked increased interest in using RT to enhance an anti-tumor immune response. However, to take advantage of the immunological effects of RT, a deeper understanding of the effects of RT on tumor-infiltrating leukocytes (TILs) is essential. Therefore, we systematically analyzed the effects of RT on tumor growth and the tumor-infiltrating immune cells in five syngeneic tumor models with diverse immune cell-infiltration profiles. These tumor types show strong differences in the overall immune cell infiltration, as well as in the composition of the infiltrating immune cell populations. After RT, tumors that were characterized as hot (e.g. CT26) showed increased sensitivity and dose-dependent tumor growth inhibition compared to cold tumor models (e.g. B16F10). Immune cell profiling indicated that RT led to strong changes in TILs of some tumor types, such as MC38 and CT26. These changes included reduced fractions of macrophages and increases in NK cells and also CD8 T cells. Single cell RNA sequencing also revealed an increase in CD8 T cells expressing proliferation-related genes. Furthermore, macrophage clusters expressing markers of proliferation were specifically eradicated by RT, while monocytes and neutrophils were less affected. The monocytes and neutrophils in the models that showed little changes in TILs after RT expressed marker genes of type-I interferon response. These findings predict that tumors that are highly infiltrated by neutrophils and monocytes, with little intra-tumoral proliferation and type-I interferon response signature, are likely resistant to an RT-mediated anti-tumor immune response. The present work has laid a strong foundation to develop next-generation combinatorial treatments using RT and immunotherapy. Citation Format: Tristan Wirtz, Catherine Lee, Tao Xie, Lisa Manzuk, Manfred Kraus, Christopher Dillon, Timothy Affolter, Anand Giddabasappa. Effects of targeted radiotherapy on tumor immune landscape in diverse murine tumor models [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P065.

An Update on Tuberculosis Vaccines.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a leading cause of mortality and morbidity due to a single infectious agent. Aerosol infection with Mtb can result in a range of responses from elimination, active, incipient, subclinical, and latent Mtb infections (LTBI), depending on the host's immune response and the dose and nature of infecting bacilli. Currently, BCG is the only vaccine approved to prevent TB. Although BCG confers protection against severe forms of childhood TB, its use in adults and those with comorbid conditions, such as HIV infection, is questionable. Novel vaccines, including recombinant BCG (rBCG), were developed to improve BCG's efficacy and use as an alternative to BCG in a vulnerable population. The first-generation rBCG vaccines had different Mtb antigens and were tested as a prime, prime-boost, or immunotherapeutic intervention. The novel vaccines target one or more of the following requirements, namely prevention of infection (POI), prevention of disease (POD), prevention of recurrence (POR), and therapeutic vaccines to treat a TB disease. Several vaccine candidates currently in development are classified into four primary categories: live attenuated whole-cell vaccine, inactivated whole-cell vaccine, adjuvanted protein subunit vaccine, and viral-vectored vaccine. Each vaccine's immunogenicity, safety, and efficacy are tested in preclinical animal models and further validated through various phases of clinical trials. This chapter summarizes the various TB vaccine candidates under different clinical trial stages and promises better protection against TB.

Topical delivery of PD‐1 inhibitors with laser‐assisted passive diffusion and active intradermal injection: Investigation of cutaneous pharmacokinetics and biodistribution patterns

Current cancer immunotherapeutic treatment with PD-1 inhibitors is administered systemically. However, a local treatment strategy may be advantageous as it could provide targeted drug delivery as well as attenuate side effects seen with systemic treatments. For keratinocyte cancers, where surgical excision is not always applicable, an alternate local treatment approach would be beneficial. This study aims to examine cutaneous pharmacokinetics and biodistribution of the PD-1 inhibitor nivolumab, locally delivered either by ablative fractional laser (AFL)-assisted passive diffusion or active intradermal injection, in vivo. In vivo pig skin was either exposed to CO2 AFL (80 mJ/mb by two stacked pulses of 40 mJ/mb) at 5% or 15% density followed by topical application of nivolumab (1 mg/ml, 100 µl/10 × 10 mm) or intradermally injected with nivolumab (1 mg/ml, 100 µl). Cutaneous nivolumab delivery was evaluated at different timepoints (0, 1, 2, 4 hours and 2 days) at two tissue depths (100-800 and 900-1600 µm) by ELISA. Visualization of cutaneous biodistribution was shown in vertical tissue sections using HiLyte FluorTM 488 SE labeled nivolumab for fluorescence microscopy whereas nivolumab was DOTA-tagged with Dysprosium before the laser ablation-inductively coupled plasma-mass spectrometry analysis (LA-ICP-MS). Our in vivo study revealed different pharmacokinetic and biodistribution patterns for the AFL- and injection techniques. A superficial horizontal band-like uptake of nivolumab was provided with AFL-assisted passive diffusion whereas a deep focal deposition was seen with active intradermal injection, compared with controls showing remnant deposition on the skin surface. AFL-assisted nivolumab uptake in upper dermis peaked after 4 hours (p < 0.01). The cutaneous concentration of nivolumab achieved by intradermal injection was markedly higher than with AFL, the highest deposition with intradermal injection was detected at time 0 hours in both upper and deep dermis (p < 0.01) and decreased throughout the study period, although the concentration remained higher compared with saline control injections at all time points (0 hours -2 d) (p < 0.01). Local cutaneous delivery of nivolumab with either AFL or intradermal injection revealed two different pharmacokinetic and biodistribution patterns. Passive AFL-assisted diffusion of nivolumab resulted in enhanced uptake after 4 hours, while intradermal actively injected nivolumab showed immediate enhanced cutaneous deposition with retention up to 2 days after injection. The two local delivery techniques show potential for development of individualized treatment strategies depending on the clinical tumor appearance.

Abstract P166: The rs35112940 CD33 polymorphism reduces CD33 internalization and efficacy of CD33-directed gemtuzumab ozogamicin

Abstract CD33 is a myeloid-specific cell surface protein widely expressed on acute myeloid leukemia (AML) cells making it an excellent immunotherapeutic target. Current CD33-directed immunotherapeutic treatment strategies include gemtuzumab ozogamicin (GO), an antibody-drug conjugate (ADC) approved in 2017 for treatment AML and other ADCs are various stages of development. Previously, studies from our group have identified germline variations in CD33 that are associated with CD33 cell surface expression levels and clinical outcomes in response to GO. Among these germline variations is rs35112940 (G&amp;gt;A; Arg304Gly), a missense polymorphism located in exon five of CD33 which is associated with lower CD33 expression and reduced benefit from treatment using GO. Herein, we functionally validated the effect of the rs35112940 variant by treating CD33KO-HL60 engineered to overexpress wildtype CD33 (HL60-CD33FL) or CD33 encoding the rs35112940 variant (HL60-CD33FL-rs35112940) with GO. After 48-hour treatment with 250 ng/mL of GO, we observed that HL60-CD33FL-rs35112940 cells were more resistant to GO than HL60-CD33FL cells (46.5% vs 66.4% cell viability, P = 0.02). Of note, all engineered cells expressed CD33 with less than 1-log fold difference in MFI (HL60-CD33FL median fluorescence intensity (MFI) vs HL60-CD33FL-rs35112940 MFI: 22536 vs 24882). One critical aspect of the mechanism of action of GO is the internalization of the GO-CD33 complex which allows free calicheamicin to induce DNA damage leading to cellular apoptosis. Given the proximity of the rs35112940 loci to the cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) domain of CD33, which is critical for CD33 internalization, we hypothesized that the rs35112940 variation may impact CD33 internalization as well. To assess this, we performed a flow cytometry-based internalization assay to capture the remaining amounts of CD33 present on the cell surface after 4 hours allowing us to determine the internalization of CD33 over time. Over a 4-hour window, we observed that that HL60-CD33FL-rs35112940 cells had an approximate 10% reduction in CD33 internalization in comparison to HL60-CD33FL cells. Taken together these results provide insight into the effect of the rs35112940 variant on GO efficacy and CD33 biology, corroborating our previous findings, and support the use of CD33 polymorphisms to guide patient selection for treatment with GO. Citation Format: Mohammed O. Gbadamosi, Vivek M. Shastri, Soheil Meshinchi, Jatinder K. Lamba. The rs35112940 CD33 polymorphism reduces CD33 internalization and efficacy of CD33-directed gemtuzumab ozogamicin [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P166.

An autoimmune stem-like CD8 T cell population drives type 1 diabetes.

CD8 T cell-mediated autoimmune diseases result from the breakdown of self-tolerance mechanisms in autoreactive CD8 T cells1. How autoimmune T cell populations arise and are sustained, and the molecular programmes defining the autoimmune T cell state, are unknown. In type 1 diabetes, β-cell-specific CD8 T cells destroy insulin-producing β-cells. Here we followed the fate of β-cell-specific CD8 T cells in non-obese diabetic mice throughout the course of type 1 diabetes. We identified a stem-like autoimmune progenitor population in the pancreatic draining lymph node (pLN), which self-renews and gives rise to pLN autoimmune mediators. pLN autoimmune mediators migrate to the pancreas, where they differentiate further and destroy β-cells. Whereas transplantation of as few as 20 autoimmune progenitors induced type 1 diabetes, as many as 100,000 pancreatic autoimmune mediators did not. Pancreatic autoimmune mediators are short-lived, and stem-like autoimmune progenitors must continuously seed the pancreas to sustain β-cell destruction. Single-cell RNA sequencing and clonal analysis revealed that autoimmune CD8 T cells represent unique T cell differentiation states and identified features driving the transition from autoimmune progenitor to autoimmune mediator. Strategies aimed at targeting the stem-like autoimmune progenitor pool could emerge as novel and powerful immunotherapeutic interventions for type 1 diabetes.

The Immunotherapy for Colorectal Cancer, Lung Cancer and Pancreatic Cancer.

Immunotherapy is a novel anti-cancer method which employs a different mechanism to conventional treatment. It has become a significant strategy because it provides a better or an alternative option for cancer patients. Recently, immunotherapy has been increasingly approved for the treatment of cancer; however, it has various limitations; for instance, it is only suitable for specific patients, the response rate is still low in most cases, etc. Colorectal cancer, lung cancer and pancreatic cancer are known as three major death-causing cancers in most countries. In this review, we discuss immunotherapeutic treatment for these three cancers, and consider the option, prospects and limitations of immunotherapy. The development of immunotherapy should focus on the discovery of biomarkers to screen suitable patients, new targets on tumors, neoadjuvant immunotherapy and the combination of immunotherapy with conventional therapeutic methods. We can expect that immunotherapy potentially will develop as one of the best therapies for patients with advanced cancer or poor responses to traditional methods.

Combination of IDO1high and CCL19low expression in the tumor tissue reduces survival in HPV positive cervical cancer

The over expression of Indoleamine 2, 3-Dioxygenase (IDO1), an immune checkpoint inhibitor, is well known in cervical cancer. However, its association with chemokine signals promoting cellular infiltration in the cervical tumor microenvironment, is unknown. In the current study, we evaluated the expression and enzymatic activity of IDO1. We also profiled the expression of chemokine ligand-receptors- CCR4-CCL22, CXCR3-CXCL10, CXCR4-CXCL12, and CCR7-CCL19 using immunohistochemistry (IHC), and studied their association with IDO1, statistically. After getting an informed consent, punch biopsy samples were obtained from 105 patients diagnosed with cervical cancer. HPV typing by Sanger sequencing, realtime PCR for quantifying IDO1 mRNA expression, HPLC for determining the K/T ratio and IHC for all the above chemokine receptor-ligand pairs along with IDO1 were performed. We found a significant increase in the expression of IDO1 and K/T levels in early and locally advanced stages when compared to Stage IV disease. Among the chemokine ligand -receptor pairs profiled, we found that high CCL19 marker expression was a good prognostic indicator of patients’ disease-free (p = 0.013) and overall survival (p = 0.043). Although we could not identify IDO1 as an independent prognostic factor, we found that high levels of IDO1 expression may further reduce survival outcomes in patients with low CCL19 expression. This could be vital for designing immuno therapeutic interventions targeting IDO1.

ACSL4 Expression Is Associated With CD8+ T Cell Infiltration and Immune Response in Bladder Cancer.

ObjectiveThis study aimed to explore the role of ACSL4 in CD8+ T cell tumor infiltration and outcomes of bladder cancer (BLCA) patients after immunotherapy.MethodsThe correlation between ACSL4 expression and tumor infiltration of immune cells was analyzed using the Tumor Immune Estimation Resource database. The prognostic significance of ACSL4 in BLCA was analyzed using Kaplan–Meier curves. Immunohistochemistry was used to detect CD8+ T cell infiltration in tumors with high and low ACSL4 expression obtained from patients at the Fudan University Shanghai Cancer Center. The relationships between immune checkpoint genes and immune response were analyzed using The Cancer Genome Atlas and IMvigor 210 cohorts. The molecular functions, cellular components, and biological processes involving ACSL4 were explored using Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment pathway analyses.ResultsThe expression level of ACSL4 was significantly correlated with the infiltration of CD8+ T cells in BLCA tumors (r = 0.192, P = 2.22e-04). Elevated ACSL4 was associated with suppressed tumor progression and better outcomes for BLCA patients. The higher expression level of ACSL4 predicted better immunotherapeutic responses and was associated with higher expression levels of core immune checkpoint genes, including CD274, CTLA4, PDCD1, and LAG3, compared with the low ACSL4 expression group.ConclusionThis study demonstrated for the first time that elevated ACSL4 correlated significantly with CD8+ T cell infiltration and contributed to better immunotherapeutic responses in BLCA patients. Furthermore, ACSL4 serves as a novel biomarker for predicting patient outcomes after immunotherapeutic treatments, which may improve the development of individualized immunotherapy for BLCA.

Detection of Vector Copy Number in Bicistronic CD19xCD22 CAR T Cell Products with Digital PCR

Chimeric antigen receptor (CAR) T cell therapy is a rapidly evolving immunotherapeutic treatment modality for adult and pediatric patients with a variety of cancers, which has been most extensively investigated in B-cell malignancies. Given that CAR T cell immunotherapy involves changing the genetic composition of a patient's T cells, this living drug presents unique safety and quality control challenges. Vector copy number (VCN), a measurement of transgene copies within a CAR T cell product, is a product-specific characteristic that must be quantified prior to patient administration as high VCN increases the risk of insertional mutagenesis.Historically, VCN assessment in CAR T cell products has been performed via qPCR. qPCR is reliable along a broad range of concentrations but has inherent limitations in its lower limit of detection and limit of quantification. Digital PCR (dPCR) methods were developed for absolute quantification of target sequences by counting nucleic acid molecules encapsulated in discrete, volumetrically defined partitions. Advantages of dPCR compared to qPCR include simplicity, reproducibility, lower limit of detection, and definitive quantification.In this present study, we developed an assay for analysis of the novel bicistronic UCD19x22 CAR T cell construct, which was developed in the laboratory of Dr. Terry Fry at the University of Colorado and will be moving in to clinical trials later this year. Custom primer-probe assays were designed using Primer Express v3.0.1 and the ThermoFisher Custom TaqMan Assay Design Tool. As an internal control, forward and reverse primers as well as a VIC-labeled probe specific to human albumin (NCBI gene 213, HGNC:399) were designed. Primers and a FAM-labeled probe assay, specific for the bicistronic CD19x22 CAR T cell product, were designed at the junction site between the two distinct CARs. This study compares two different digital PCR modalities: (1) droplet digital PCR (ddPCR) via the BioRad QX200 system which utilizes water-in-oil droplet partitions and (2) the QIAcuity digital PCR system utilizing a nanoplate-based partitioning platform. While dPCR is a newer methodology compared to ddPCR, the two apply parallel procedures, data generation, and analyses. The primer/probe assay was validated with qPCR, dPCR and ddPCR using patient samples from preclinical CAR T cell manufacturing production runs, as well as Jurkat cell subclones which stably express this bicistronic CAR T product.We successfully developed an assay to specifically detect and quantify our bicistronic CD19xCD22 CAR transgene. ddPCR confirmed the specificity of this assay to detect only the bicistronic CAR product without any signal detected in samples containing untransduced T cells or T cells transduced with CD19 only CARs. Additionally, our assay gives accurate, precise, and reproducible CAR T cell VCN measurements across qPCR, dPCR, and ddPCR modalities. We demonstrate that digital PCR strategies can be utilized for absolute quantification of CAR transgenes and VCN measurements, and that specific assays can be developed for detection of unique constructs. Future studies will evaluate the utility of this assay with digital PCR modalities in measuring CAR T cell persistence in clinical trial patient samples after receiving this novel CAR T cell product. [Display omitted] DisclosuresFry: Sana Biotechnology: Current Employment, Current equity holder in publicly-traded company.

The rs35112940 CD33 Polymorphism Reduces CD33 Internalization and Efficacy of CD33-Directed Gemtuzumab Ozogamicin

BackgroundCD33 is a myeloid-specific cell surface protein widely expressed on acute myeloid leukemia (AML) cells making it an excellent immunotherapeutic target. Current CD33-directed immunotherapeutic treatment strategies include gemtuzumab ozogamicin (GO), an antibody-drug conjugate (ADC) which was approved for the treatment AML in 2017 and has demonstrated promising results thus far. The mechanism of action of GO begins with recognition of CD33 by the antibody portion of GO, followed by internalization of the CD33-GO complex, and finally delivery of free calicheamicin molecules to the cell to induce cellular apoptosis. As such, modifications that impact these steps on any level presumably impact the response and overall efficacy of GO. Indeed, previous studies from our group have identified germline variations in CD33 that are associated with differences in CD33 structure, CD33 cell surface expression levels, and clinical outcomes in response to GO. Among these germline variations is rs35112940 (G>A; Arg304Gly), a missense polymorphism which is located in exon five of CD33 adjacent to the cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) domain, a critical feature for CD33 internalization. While our previous work identified statistical associations between the A allele of rs35112940 and lower CD33 expression and reduced benefit from treatment using GO, these results are yet to be validated functionally. Additionally, it still remains unknown if the impact of the rs35112940 variation is due to reduced CD33 expression alone or if the rs35112940 variation also impacts CD33 internalization thereby modulating CD33 efficacy.MethodsTo functionally validate the effect of the rs35112940 variant, we used CRISPR/cas9 to knockout CD33 in HL60 cells and subsequently engineered the HL60-CD33 KO cells to express either wildtype CD33 (HL60-CD33 FL) or CD33 encoding the rs35112940 variant (HL60-CD33 FL-rs35112940). The engineered cells were then treated with GO for 48 hours to capture the impact of the rs35112940 variation on the efficacy of GO. To assess the impact of the rs35112940 variation on CD33 internalization, we performed a flow cytometry-based internalization assay using secondary antibodies to capture the remaining amounts of CD33 present on the cell surface after 4 hours allowing us to determine the internalization of CD33 over time.ResultsAll engineered cells expressed CD33 with less than 1-log fold difference in median fluorescence intensity (MFI) (HL60-CD33 FL MFI vs HL60-CD33 FL-rs35112940 MFI: 22536 vs 24882, Figure 1) and thus we were able to characterize the impact of the rs35112940 variant independent of its impact on CD33 cell surface expression. After 48-hour treatment with 250 ng/mL of GO, we observed that HL60-CD33 FL-rs35112940 cells were more resistant to GO than HL60-CD33 FL cells (66.4% vs 46.5% cell viability, P = 0.02, Figure 2A). Similar results were observed at multiple concentrations of GO. Given the proximity of the rs35112940 loci to the ITIM domain of CD33, we hypothesized that the rs35112940 variation may impact CD33 internalization as well. In a flow cytometry-based internalization assay over a 4-hour window, we observed that that HL60-CD33 FL-rs35112940 cells had an approximate 10% reduction in CD33 internalization in comparison to HL60-CD33 FL cells (Figure 2B). Taken together these results provide insight into the effect of the rs35112940 variant on GO efficacy and CD33 biology, corroborating our previous findings, and support the use of CD33 polymorphisms to guide patient selection for treatment with GO. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

In Situ Vaccination Induces Changes in Follicular Lymphoma Tumor Cells That Correlate with Abscopal Clinical Regressions

In Situ Vaccination Induces Changes in Follicular Lymphoma Tumor Cells That Correlate with Abscopal Clinical Regressions

230 Preclinical efficacy of CLEC-1 antagonist as novel myeloid immune checkpoint therapy for oncology

BackgroundC-type lectin receptors (CLRs) are powerful pattern recognition receptors shaping immune cell-mediated tissue damage by positively or negatively regulating myeloid cell functions and hence tumor elimination or evasion. We previously reported that the orphan CLR CLEC-1 expressed by dendritic cells (DCs) tempers T cell’s responses in vivo by limiting antigen cross-presentation by cDC1. Furthermore, we observed that CLEC-1 is highly expressed by myeloid cells purified from human tumor microenvironment, in particular tumor-associated macrophages.MethodsMacrophages were generated from monocytes of healthy volunteers for phagocytosis assays. MC38 and Hepa 1.6 murine tumor cells were implanted in Clec1a KO or KI mice for immunotherapeutic treatment evaluation.ResultsUsing newly developed anti-human CLEC-1 monoclonal antibodies (mAbs), we found that antagonist anti-CLEC-1 mAbs with the capacity to block CLEC-1/CLEC-1Ligand interaction, as opposed to non-antagonist CLEC-1 mAbs, increase the phagocytosis of CLEC-1Ligand-positive human tumor cells by human macrophages, in particular when opsonized by tumor-associated antigen mAbs (Rituximab, Cetuximab, Trastuzumab) or with anti-CD47 mAb (Magrolimab). In-vivo, CLEC-1 knock-out (KO) mice (n=19) display significant prolonged survival in monotherapy as compared to wild-type littermates (n=12) in an orthotopic hepatocellular carcinoma (HCC) model and anti-tumor memory responses was demonstrated by tumor rechallenge in cured mice. CLEC1 KO mice also illustrate significant eradication of MC38 colorectal tumors in combination with chemotherapy promoting CLEC-1Ligand expression by tumor cells (n=16 with Gemcitabine or n=11 with Cyclophosphamide). HCC tumor microenvironment analysis after 2 weeks of tumor implantation shows significantly higher number of CD8+ and memory CD8+ T cells with reduced PD1 expression in CLEC1 KO animals (n=16 versus n=12 for KO vs WT mice respectively). Finally, we recently generated human CLEC-1 knock-in mice expressing the extracellular human CLEC1 domain fused to the intracellular mouse CLEC1 tail and confirmed preclinical efficacy in vivo with anti-human CLEC1 antagonist mAb in monotherapy in the orthotopic HCC model.ConclusionsThese data illustrate that CLEC-1 inhibition represents a novel therapeutic target for immuno-oncology modifying T cell immune responses and tumor cell phagocytosis by macrophages.

The Potential Advantage of Targeting Both PD-L1/PD-L2/PD-1 and IL-10-IL-10R Pathways in Acute Myeloid Leukemia.

Tumor cells promote the suppression of host anti-tumor type 1 T cell responses by various mechanisms, including the upregulation of surface inhibitory molecules such as programmed death ligand (PD-L)-1, and the production of immunosuppressive cytokines such as interleukin-10 (IL-10). There are over 2000 trials investigating PD-L1 and/or its receptor programmed-death 1 (PD-1) blockade in cancer, leading to the approval of PD-1 or PD-L1 inhibitors in several types of solid cancers and in hematological malignancies. The available data suggest that the molecule PD-L1 on antigen-presenting cells suppresses type 1 T cell immune responses such as cytotoxicity, and that the cytokine IL-10, in addition to downregulating immune responses, increases the expression of inhibitory molecule PD-L1. We hypothesize that the manipulation of both the co-inhibitory network (with anti-PD-L1 blocking antibodies) and suppressor network (with anti-IL-10 blocking antibodies) is an attractive immunotherapeutic intervention for acute myeloid leukemia (AML) patients ineligible for standard treatment with chemotherapy and hematopoietic stem cell transplantation, and with less severe adverse reactions. The proposed combination of these two immunotherapies represents a new approach that can be readily translated into the clinic to improve the therapeutic efficacy of AML disease treatment.

Systematic review on the current knowledge and use of single-cell RNA sequencing in head and neck cancer.

Single-cell RNA sequencing (scRNA-seq) is a novel method enabling genetic characterization of tumor tissue at a single-cell level. This study systematically reviewed the literature on studies using scRNA-seq to characterize head and neck squamous cell carcinomas (HNSCCs). Seven studies were included, of which two studies performed scRNA-seq on 20 patients in total, and five studies used scRNA-seq data in a subsequent clinical study. The former mentioned two studies found intra-tumoral genetic heterogeneity among malignant cells but genetic uniformity among non-malignant cells. The five latter studies used scRNA-seq data in various ways. Three studies identified biomarkers related to predicting whether a patient would benefit from immunotherapeutic treatment. One study characterized genes related to the perineural invasion. One study identified genes to be used in diagnostics. Further studies performing scRNA-seq on HNSCC are required to continue the ongoing development and use of scRNA-seq.

Tumor-Associated Mast Cells in Urothelial Bladder Cancer: Optimizing Immuno-Oncology.

Urothelial bladder cancer (UBC) is one of the most prevalent and aggressive malignancies. Recent evidence indicates that the tumor microenvironment (TME), including a variety of immune cells, is a critical modulator of tumor initiation, progression, evolution, and treatment resistance. Mast cells (MCs) in UBC are possibly involved in tumor angiogenesis, tissue remodeling, and immunomodulation. Moreover, tumor-infiltration by MCs has been reported in early-stage UBC patients. This infiltration is linked with a favorable or unfavorable prognosis depending on the tumor type and location. Despite the discrepancy of MC function in tumor progression, MCs can modify the TME to regulate the immunity and infiltration of tumors by producing an array of mediators. Nonetheless, the precise role of MCs in UBC tumor progression and evolution remains unknown. Thus, this review discusses some critical roles of MCs in UBC. Patients with UBC are treated at both early and late stages by immunotherapeutic methods, including intravenous bacillus Calmette–Guérin instillation and immune checkpoint blockade. An understanding of the patient response and resistance mechanisms in UBC is required to unlock the complete potential of immunotherapy. Since MCs are pivotal to understand the underlying processes and predictors of therapeutic responses in UBC, our review also focuses on possible immunotherapeutic treatments that involve MCs.

Modulating expression of inhibitory and stimulatory immune 'checkpoints' using nanoparticulate-assisted nucleic acid delivery.

Immune checkpoints are regulatory molecules responsible for determining the magnitude and nature of the immune response. The aim of immune checkpoint targeting immunotherapy is to manipulate these interactions, engaging the immune system in treatment of cancer. Clinically, the use of monoclonal antibodies to block immunosuppressive interactions has proven itself to be a highly effective immunotherapeutic intervention. Within the literature there are numerous candidates for next generation of immune checkpoint targeting strategies. One such example is the use of nucleic acid to alter expression levels of immune checkpoint molecules, either as antisense oligo nucleotides/siRNA, to downregulate inhibitory molecules, or mRNA/DNA, to express co-stimulatory molecules. A significant component of nucleic acid delivery is its formulation within a nanoparticulate system. In this review we discuss the progress of the preclinical application of nucleic acid-based immunotherapies to target a selection of co-inhibitory/co-stimulatory molecules. Furthermore, we identify the potential and current gaps within the literature which may form the basis of future work.

Immunogenic Cell Death and Immunomodulatory Effects of Cabozantinib.

Cabozantinib (XL-184) is a multitarget tyrosine kinase inhibitor (TKI) targeting receptor tyrosine kinases (RTKs) involved in oncogenesis and angiogenesis. It is currently the standard therapy for medullary thyroid cancer (MTC), metastatic renal cell carcinoma (mRCC), and hepatocellular carcinoma (HCC). Combination of Cabozantinib with immunotherapy is now a standard treatment in metastatic renal cancer, and its efficacy is being tested in ongoing clinical trial in prostate cancer patients. Here, we report that Cabozantinib may exert an immunostimulatory role by inducing immunogenic stress of prostate cancer cells and directly modulating dendritic cells (DCs). Cabozantinib treatment arrested the cell cycle and triggered immunogenic cell death (ICD) in prostate cancer cells in vitro. Cabozantinib had a direct effect on DCs by the down-modulation of β-catenin and change in migratory and costimulatory phenotype of the DCs. These results may suggest possible immunomodulatory effects induced by Cabozantinib that could be exploited to optimize patient-tailored immunotherapeutic treatments.

Immune checkpoint molecule TIGIT manipulates T cell dysfunction in septic patients

Sepsis is a dysregulated host response to infection. T cell dysfunction results in the failure to eradicate pathogens and the increased susceptibility to nosocomial infections and mortality during sepsis. Although PD-1 has shown to be a promising target to interfere with T cells dysfunction, the role of other coinhibitory receptors in sepsis remains largely elusive. Here we demonstrated that the immune checkpoint molecule TIGIT on lymphocytes and the critical role of TIGIT in regulating T cell responses in sepsis. Fifty septic patients and seventeen healthy donors were prospectively enrolled. The expression patterns of TIGIT and other molecules on lymphocytes were quantitated by flow cytometry. Ex vivo functional assays were also conducted. Results show that TIGIT expression on T cells was significantly upregulated in sepsis and septic shock patients relative to healthy donors. Elevated frequencies of TIGIT+ T cells correlated with aggravated inflammatory response and organ injuries. Of note, TIGIT expression on CD8+ T cells showed a competitive capability to predict ICU mortality in sepsis. TIGIT+ T cells expressed higher levels of PD-1, lower levels of CD226, and released fewer cytokines. Strikingly, ex vivo blockade of TIGIT using anti-TIGIT antibody restored the frequencies of cytokine-producing T cells from septic patients. These data illustrate that TIGIT on T cells is being used not only as a clinical predictor of poor prognosis but also as a potential target of novel immunotherapeutic intervention during sepsis.

Critical care management of chimeric antigen receptor T-cell therapy recipients.

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapeutic treatment concept that is changing the treatment approach to hematologic malignancies. The development of CAR T-cell therapy represents a prime example for the successful bench-to-bedside translation of advances in immunology and cellular therapy into clinical practice. The currently available CAR T-cell products have shown high response rates and long-term remissions in patients with relapsed/refractory acute lymphoblastic leukemia and relapsed/refractory lymphoma. However, CAR T-cell therapy can induce severe life-threatening toxicities such as cytokine release syndrome, neurotoxicity, or infection, which require rapid and aggressive medical treatment in the intensive care unit setting. In this review, the authors provide an overview of the state-of-the-art in the clinical management of severe life-threatening events in CAR T-cell recipients. Furthermore, key challenges that have to be overcome to maximize the safety of CAR T cells are discussed.

Is there a role for neoadjuvant anti-PD-1 therapies in glioma?

In this review, we summarized recent findings that highlight the progress for checkpoint blockade immunotherapy in glioblastoma (GBM) patients. We reviewed new data from our group and others that suggest that the timing of when immunotherapy is applied can impact the antitumor immune response and, potentially, the ultimate clinical benefit of patients. The neoadjuvant priming and expansion of exhausted T cells within the GBM microenvironment, followed by the removal of an immune suppressive tumor microenvironment through surgical resection, may lead to enhanced antitumor immune responses that are beneficial clinically. As such, neoadjuvant immunotherapeutic approaches and rational combinations may be helpful scientifically to understand how immunotherapeutic interventions influence the tumor microenvironment, as well benefit the patients.