scholarly journals 3373 Modulation of Hedgehog Signaling Alters Immune Infiltration in Pancreatic Cancer

2019 ◽  
Vol 3 (s1) ◽  
pp. 16-16
Author(s):  
Nina Steele ◽  
Valerie Irizarry-Negron ◽  
Veerin Sirihorachai ◽  
Samantha Kemp ◽  
Eileen Carpenter ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Bone Marrow ◽  
Tumor Microenvironment ◽  
Mouse Model ◽  
Tumor Cells ◽  
Pancreatic Tumors ◽  
Hh Signaling ◽  
Immune Profiling

OBJECTIVES/SPECIFIC AIMS: Pancreatic ductal adenocarcinoma (PDA) has a dismal 5-year survival rate of 9%, making this disease one of the deadliest human malignancies (https://seer.cancer.gov/). Primary barriers to the treatment of pancreatic cancer include extensive stromal interactions and sustained immune suppression. Aberrant Hedgehog (HH) pathway activity is a hallmark of pancreatic tumorigenesis. Tumor-derived HH ligands signal in a paracrine fashion to the surrounding stroma to influence tumor growth. Expression of HH ligands increases during PDA progression, and previous work has shown that genetic deletion of Sonic HH (Shh) from the epithelium of mice with pancreatic tumors results in increased Indian HH (Ihh) expression. This research aims to investigate the translational impact of changes in immune infiltration following deletion of IHH in a preclinical mouse model of pancreatic cancer. METHODS/STUDY POPULATION: Ihh was deleted in tumor cells lines (IhhKO) derived from a genetically engineered mouse model of pancreatic cancer (LSL-KrasG12D/+;LSL-TrpR270H;P48-Cre), using CRISPR/Cas-9 gene editing to assess the role of Ihh in the tumor microenvironment. The level of HH signaling was determined using tumor cell co-cultures with Gli1lacZ fibroblasts (derived from mice with a lacZ reporter allele knocked into the Gli1 locus), in which Beta Galactosidase activity serves as a readout for HH signaling. WT and IhhKO tumor cells were orthotopically transplanted into the pancreas of syngeneic C57BL/6 mice. Human pancreas samples were obtained from surgical resection of pancreatic adenocarcinoma, or fine needle biopsy procedure (FNB). Immune profiling of mouse and human pancreatic tumors was performed using Cytometry Time-of-Flight analysis (CyTOF), and tumor composition was analyzed by single-cell RNA sequencing (scRNA seq). In vitro cultures with pancreatic fibroblasts treated with either WT or IhhKO tumor cell conditioned media (CM) were cultured with bone-marrow derived macrophages to assess tumor crosstalk. RESULTS/ANTICIPATED RESULTS: Tumor cells lacking Ihh were generated through CRISPR/Cas-9 deletion, and this was confirmed by qRT-PCR. Co-culture of IhhKO tumor cells with Gli1lacZ fibroblasts results in decreased Gli1 expression both in vitro and in vivo. Immune profiling revealed that tumors lacking Ihh have significantly fewer tumor associated macrophages (CD11b+/F4/80+/CD206+), resulting in decreased presence of immunosuppressive factors such as arginase 1 and PDL1. Immune phenotyping of human pancreatic tissues revealed similar populations of immunosuppressive myeloid cells present in tumors. In vitro co-cultures demonstrated that, in the presence of bone-marrow derived macrophages, immunosuppressive IL-6 production was reduced in pancreatic fibroblasts cultured with IhhKO-CM, as compared to fibroblasts cultured with WT-CM, providing mechanistic insight into the in vivo phenotype observed. Further, scRNA seq analysis suggests that modulation of HH signaling in the tumor microenvironment alters chemokine and immunomodulatory signaling pathways driven by fibroblasts in the pancreatic tumor microenvironment. DISCUSSION/SIGNIFICANCE OF IMPACT: HH signaling in pancreatic fibroblasts contributes to the establishment of an immune suppressive environment in pancreatic cancer. Combining methods to target HH signaling and immune checkpoint therapy has translational potential in treating pancreatic cancer patients.

TAMI-51. HORIZONTAL MITOCHONDRIAL TRANSFER FROM THE TUMOR MICROENVIRONMENT TO GLIOBLASTOMA INCREASES TUMORIGENICITY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi208-vi209
Author(s):  
Dionysios Watson ◽  
Defne Bayik ◽  
Justin Lathia
Keyword(s):  
Bone Marrow ◽  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Bone Marrow Cells ◽  
Treatment Strategies ◽  
Tumor Initiating Cells ◽  
Mitochondrial Transfer ◽  
Mitochondria Transfer

Abstract Communication between glioblastoma (GBM) and its microenvironment facilitates tumor growth and therapeutic resistance, and is facilitated through a variety of mechanisms. Organelle transfer between cells was recently observed, including mitochondria transfer from astrocytes to neurons after ischemic stroke. Given the dependence of GBM on microenvironmental interactions, we hypothesized that mitochondria transfer from tumor microenvironment to GBM cells could occur and affect metabolism and tumorigenicity. We interrogated this in vivo by establishing intracranial GBM tumors in mito::mKate2 mice (with trackable fluorescent mitochondria) using syngeneic GFP-expressing tumor cells (SB28 and GL261 models). We also cultured stromal cell types from mito::mKate2 mice with tumor cells, enabling sorting of tumor cells with and without exogenous mitochondria. Confocal microscopy revealed horizontal transfer of mKate2+ mitochondria from mouse cells to implanted GBM cells in vivo and was confirmed by flow cytometry where 20-40% of GBM cells acquired exogenous mitochondria. Transfer was negligible in wildtype mice transplanted with mito::mKate2 bone marrow cells, suggesting that brain-resident cells were the main donors. In vitro, astrocytes and microglia exhibited 5 to 10-fold higher mitochondrial transfer rate than bone-marrow derived macrophages. Seahorse metabolic profiling revealed that GBM cells with mKate2+ mitochondria had 40% lower respiratory reserve compared to cells without exogenous mitochondria. Median survival of mice implanted with SB28 that acquired mitochondria was significantly shorter and in vivo limiting dilution confirmed the frequency of tumor-initiating cells was 3-fold higher in SB28 cells with exogenous mitochondria. Our data indicate that horizontal mitochondrial transfer from brain-resident glia to mouse GBM tumors alters tumor cell metabolism and increases their tumorigenicity. Ongoing studies are assessing gene expression in GBM cells acquiring exogenous mitochondria; validating findings in human specimens; and screening for transfer inhibitor drugs. Horizontal mitochondrial transfer represents a foundational tumor microenvironment interaction contributing to glioblastoma plasticity, and is likely to inform next-generation treatment strategies.

scholarly journals Exosome-transported circRNA_0001236 enhances chondrogenesis and suppress cartilage degradation via the miR-3677-3p/Sox9 axis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guping Mao ◽  
Yiyang Xu ◽  
Dianbo Long ◽  
Hong Sun ◽  
Hongyi Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mouse Model ◽  
Chondrogenic Differentiation ◽  
Cartilage Degradation ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Luciferase Reporter ◽  
Gene And Protein Expression

Abstract Objectives Aberrations in exosomal circular RNA (circRNA) expression have been identified in various human diseases. In this study, we investigated whether exosomal circRNAs could act as competing endogenous RNAs (ceRNAs) to regulate the pathological process of osteoarthritis (OA). This study aimed to elucidate the specific MSC-derived exosomal circRNAs responsible for MSC-mediated chondrogenic differentiation using human bone marrow-derived MSCs (hMSCs) and a destabilization of the medial meniscus (DMM) mouse model of OA. Methods Exosomal circRNA deep sequencing was performed to evaluate the expression of circRNAs in human bone marrow-derived MSCs (hMSCs) induced to undergo chondrogenesis from day 0 to day 21. The regulatory and functional roles of exosomal circRNA_0001236 were examined on day 21 after inducing chondrogenesis in hMSCs and were validated in vitro and in vivo. The downstream target of circRNA_0001236 was also explored in vitro and in vivo using bioinformatics analyses. A luciferase reporter assay was used to evaluate the interaction between circRNA_0001236 and miR-3677-3p as well as the target gene sex-determining region Y-box 9 (Sox9). The function and mechanism of exosomal circRNA_0001236 in OA were explored in the DMM mouse model. Results Upregulation of exosomal circRNA_0001236 enhanced the expression of Col2a1 and Sox9 but inhibited that of MMP13 in hMSCs induced to undergo chondrogenesis. Moreover, circRNA_0001236 acted as an miR-3677-3p sponge and functioned in human chondrocytes via targeting miR-3677-3p and Sox9. Intra-articular injection of exosomal circRNA_0001236 attenuated OA in the DMM mouse model. Conclusions Our results reveal an important role for a novel exosomal circRNA_0001236 in chondrogenic differentiation. Overexpression of exosomal circRNA_0001236 promoted cartilage-specific gene and protein expression through the miR-3677-3p/Sox9 axis. Thus, circRNA_0001236-overexpressing exosomes may alleviate cartilage degradation, suppressing OA progression and enhancing cartilage repair. Our findings provide a potentially effective therapeutic strategy for treating OA.

scholarly journals Indirect cholinergic activation slows down pancreatic cancer growth and tumor-associated inflammation

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Paulo L. Pfitzinger ◽  
Laura Fangmann ◽  
Kun Wang ◽  
Elke Demir ◽  
Engin Gürlevik ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Mouse Model ◽  
Tumor Stage ◽  
Ache Inhibitors ◽  
Impact On Survival ◽  
The Impact ◽  
Ache Expression ◽  
Cholinergic Activation

Abstract Background Nerve-cancer interactions are increasingly recognized to be of paramount importance for the emergence and progression of pancreatic cancer (PCa). Here, we investigated the role of indirect cholinergic activation on PCa progression through inhibition of acetylcholinesterase (AChE) via clinically available AChE-inhibitors, i.e. physostigmine and pyridostigmine. Methods We applied immunohistochemistry, immunoblotting, MTT-viability, invasion, flow-cytometric-cell-cycle-assays, phospho-kinase arrays, multiplex ELISA and xenografted mice to assess the impact of AChE inhibition on PCa cell growth and invasiveness, and tumor-associated inflammation. Survival analyses were performed in a novel genetically-induced, surgically-resectable mouse model of PCa under adjuvant treatment with gemcitabine+/−physostigmine/pyridostigmine (n = 30 mice). Human PCa specimens (n = 39) were analyzed for the impact of cancer AChE expression on tumor stage and survival. Results We discovered a strong expression of AChE in cancer cells of human PCa specimens. Inhibition of this cancer-cell-intrinsic AChE via pyridostigmine and physostigmine, or administration of acetylcholine (ACh), diminished PCa cell viability and invasion in vitro and in vivo via suppression of pERK signaling, and reduced tumor-associated macrophage (TAM) infiltration and serum pro-inflammatory cytokine levels. In the novel genetically-induced, surgically-resectable PCa mouse model, adjuvant co-therapy with AChE blockers had no impact on survival. Accordingly, survival of resected PCa patients did not differ based on tumor AChE expression levels. Patients with higher-stage PCa also exhibited loss of the ACh-synthesizing enzyme, choline-acetyltransferase (ChAT), in their nerves. Conclusion For future clinical trials of PCa, direct cholinergic stimulation of the muscarinic signaling, rather than indirect activation via AChE blockade, may be a more effective strategy.

scholarly journals Differentiated glioblastoma cells accelerate tumor progression by shaping the tumor microenvironment via CCN1-mediated macrophage infiltration

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Atsuhito Uneda ◽  
Kazuhiko Kurozumi ◽  
Atsushi Fujimura ◽  
Kentaro Fujii ◽  
Joji Ishida ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Progression ◽  
Tumor Cells ◽  
In Silico ◽  
Tumor Tissue ◽  
The Cancer Genome Atlas ◽  
Macrophage Infiltration ◽  
Macrophage Migration

AbstractGlioblastoma (GBM) is the most lethal primary brain tumor characterized by significant cellular heterogeneity, namely tumor cells, including GBM stem-like cells (GSCs) and differentiated GBM cells (DGCs), and non-tumor cells such as endothelial cells, vascular pericytes, macrophages, and other types of immune cells. GSCs are essential to drive tumor progression, whereas the biological roles of DGCs are largely unknown. In this study, we focused on the roles of DGCs in the tumor microenvironment. To this end, we extracted DGC-specific signature genes from transcriptomic profiles of matched pairs of in vitro GSC and DGC models. By evaluating the DGC signature using single cell data, we confirmed the presence of cell subpopulations emulated by in vitro culture models within a primary tumor. The DGC signature was correlated with the mesenchymal subtype and a poor prognosis in large GBM cohorts such as The Cancer Genome Atlas and Ivy Glioblastoma Atlas Project. In silico signaling pathway analysis suggested a role of DGCs in macrophage infiltration. Consistent with in silico findings, in vitro DGC models promoted macrophage migration. In vivo, coimplantation of DGCs and GSCs reduced the survival of tumor xenograft-bearing mice and increased macrophage infiltration into tumor tissue compared with transplantation of GSCs alone. DGCs exhibited a significant increase in YAP/TAZ/TEAD activity compared with GSCs. CCN1, a transcriptional target of YAP/TAZ, was selected from the DGC signature as a candidate secreted protein involved in macrophage recruitment. In fact, CCN1 was secreted abundantly from DGCs, but not GSCs. DGCs promoted macrophage migration in vitro and macrophage infiltration into tumor tissue in vivo through secretion of CCN1. Collectively, these results demonstrate that DGCs contribute to GSC-dependent tumor progression by shaping a mesenchymal microenvironment via CCN1-mediated macrophage infiltration. This study provides new insight into the complex GBM microenvironment consisting of heterogeneous cells.

scholarly journals Pancreatic tumor cell metastasis is restricted by MT1-MMP binding protein MTCBP-1

2018 ◽  
Vol 218 (1) ◽  
pp. 317-332 ◽  
Author(s):  
Li Qiang ◽  
Hong Cao ◽  
Jing Chen ◽  
Shaun G. Weller ◽  
Eugene W. Krueger ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Pancreatic Tumor ◽  
Binding Protein ◽  
Critical Role ◽  
Inverse Correlation ◽  
Pancreatic Tumors ◽  
Matrix Remodeling ◽  
Peripheral Tissues

The process by which tumor cells mechanically invade through surrounding stroma into peripheral tissues is an essential component of metastatic dissemination. The directed recruitment of the metalloproteinase MT1-MMP to invadopodia plays a critical role in this invasive process. Here, we provide mechanistic insight into MT1-MMP cytoplasmic tail binding protein 1 (MTCBP-1) with respect to invadopodia formation, matrix remodeling, and invasion by pancreatic tumor cells. MTCBP-1 localizes to invadopodia and interacts with MT1-MMP. We find that this interaction displaces MT1-MMP from invadopodia, thereby attenuating their number and function and reducing the capacity of tumor cells to degrade matrix. Further, we observe an inverse correlation between MTCBP-1 and MT1-MMP expression both in cultured cell lines and human pancreatic tumors. Consistently, MTCBP-1–expressing cells show decreased ability to invade in vitro and metastasize in vivo. These findings implicate MTCBP-1 as an inhibitor of the metastatic process.

scholarly journals Assessment of phagocytic activity in live macrophages-tumor cells co-cultures by Confocal and Nomarski Microscopy

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Dalia Martinez-Marin ◽  
Courtney Jarvis ◽  
Thomas Nelius ◽  
Stéphanie Filleur
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Phagocytic Activity ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Functional Assay ◽  
Loss Of Function ◽  
Multiple Cancer

Abstract Macrophages have been recognized as the main inflammatory component of the tumor microenvironment. Although often considered as beneficial for tumor growth and disease progression, tumor-associated macrophages have also been shown to be detrimental to the tumor depending on the tumor microenvironment. Therefore, understanding the molecular interactions between macrophages and tumor cells in relation to macrophages functional activities such as phagocytosis is critical for a better comprehension of their tumor-modulating action. Still, the characterization of these molecular mechanisms in vivo remains complicated due to the extraordinary complexity of the tumor microenvironment and the broad range of tumor-associated macrophage functions. Thus, there is an increasing demand for in vitro methodologies to study the role of cell–cell interactions in the tumor microenvironment. In the present study, we have developed live co-cultures of macrophages and human prostate tumor cells to assess the phagocytic activity of macrophages using a combination of Confocal and Nomarski Microscopy. Using this model, we have emphasized that this is a sensitive, measurable, and highly reproducible functional assay. We have also highlighted that this assay can be applied to multiple cancer cell types and used as a selection tool for a variety of different types of phagocytosis agonists. Finally, combining with other studies such as gain/loss of function or signaling studies remains possible. A better understanding of the interactions between tumor cells and macrophages may lead to the identification of new therapeutic targets against cancer.

scholarly journals The MEMIC: An ex vivo system to model the complexity of the tumor microenvironment

2021 ◽  
Author(s):  
Libuše Janská ◽  
Libi Anandi ◽  
Nell C. Kirchberger ◽  
Zoran S. Marinkovic ◽  
Logan T. Schachtner ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Ex Vivo ◽  
Tumor Stroma ◽  
Stem Cell Differentiation ◽  
Blood Stream ◽  
Direct Access ◽  
Ex Vivo Model

There is an urgent need for accurate, scalable, and cost-efficient experimental systems to model the complexity of the tumor microenvironment. Here, we detail how to fabricate and use the Metabolic Microenvironment Chamber (MEMIC) – a 3D-printed ex vivo model of intratumoral heterogeneity. A major driver of the cellular and molecular diversity in tumors is the accessibility to the blood stream that provides key resources such as oxygen and nutrients. While some tumor cells have direct access to these resources, many others must survive under progressively more ischemic environments as they reside further from the vasculature. The MEMIC is designed to simulate the differential access to nutrients and allows co-culturing different cell types, such as tumor and immune cells. This system is optimized for live imaging and other microscopy-based approaches, and it is a powerful tool to study tumor features such as the effect of nutrient scarcity on tumor-stroma interactions. Due to its adaptable design and full experimental control, the MEMIC provide insights into the tumor microenvironment that would be difficult to obtain via other methods. As a proof of principle, we show that cells sense gradual changes in metabolite concentration resulting in multicellular spatial patterns of signal activation and cell proliferation. To illustrate the ease of studying cell-cell interactions in the MEMIC, we show that ischemic macrophages reduce epithelial features in neighboring tumor cells. We propose the MEMIC as a complement to standard in vitro and in vivo experiments, diversifying the tools available to accurately model, perturb, and monitor the tumor microenvironment, as well as to understand how extracellular metabolites affect other processes such as wound healing and stem cell differentiation.

In Vivo and in Vitro Pharmacologic Purification of Bone Marrow Contaminated with Tumor Cells Using VP16-213 and Nitrogen Mustard

1984 ◽  
pp. 183-196 ◽  
Author(s):  
Patrick J. Stiff ◽  
Thomas P. U. Wustrow ◽  
Alan R. Koester ◽  
Michael F. Derisi ◽  
Bayard D. Clarkson
Keyword(s):  
Bone Marrow ◽  
Tumor Cells ◽  
Nitrogen Mustard

scholarly journals Thioholgamide A, a New Anti-Proliferative Anti-Tumor Agent, Modulates Macrophage Polarization and Metabolism

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1288 ◽  
Author(s):  
Charlotte Dahlem ◽  
Wei Xiong Siow ◽  
Maria Lopatniuk ◽  
William K. F. Tse ◽  
Sonja M. Kessler ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Cell Metabolism ◽  
Macrophage Polarization ◽  
Human Monocyte ◽  
Live Cell ◽  
Hallmarks Of Cancer ◽  
Culture Models

Natural products represent powerful tools searching for novel anticancer drugs. Thioholgamide A (thioA) is a ribosomally synthesized and post-translationally modified peptide, which has been identified as a product of Streptomyces sp. MUSC 136T. In this study, we provide a comprehensive biological profile of thioA, elucidating its effects on different hallmarks of cancer in tumor cells as well as in macrophages as crucial players of the tumor microenvironment. In 2D and 3D in vitro cell culture models thioA showed potent anti-proliferative activities in cancer cells at nanomolar concentrations. Anti-proliferative actions were confirmed in vivo in zebrafish embryos. Cytotoxicity was only induced at several-fold higher concentrations, as assessed by live-cell microscopy and biochemical analyses. ThioA exhibited a potent modulation of cell metabolism by inhibiting oxidative phosphorylation, as determined in a live-cell metabolic assay platform. The metabolic modulation caused a repolarization of in vitro differentiated and polarized tumor-promoting human monocyte-derived macrophages: ThioA-treated macrophages showed an altered morphology and a modulated expression of genes and surface markers. Taken together, the metabolic regulator thioA revealed low activities in non-tumorigenic cells and an interesting anti-cancer profile by orchestrating different hallmarks of cancer, both in tumor cells as well as in macrophages as part of the tumor microenvironment.

scholarly journals 3502 Stimulating iNKT Cell-Mediated Neuroblastoma Cytotoxicity in a Mouse Model

2019 ◽  
Vol 3 (s1) ◽  
pp. 21-21
Author(s):  
Kevin Owen McNerney ◽  
Hamid Bassiri ◽  
Spyridon Karageorgos ◽  
Priya Khurana
Keyword(s):  
Tumor Microenvironment ◽  
Mouse Model ◽  
Neuroblastoma Cells ◽  
Prolonged Survival ◽  
Inkt Cell ◽  
Inkt Cells ◽  
Glycolipid Antigen ◽  
High Affinity

OBJECTIVES/SPECIFIC AIMS: Overall Research Aim: To develop an iNKT-cell engaging reagent (“CAb”)to induce neuroblastoma-directed cytotoxicity in vitro and in a mouse model of neuroblastoma. Objective 1: Explore the contribution of different GD2 affinities to the cytotoxicity against neuroblastoma cells in vitro. Objective 2: Deteremine whether use of different stimulatory glycolipids (alpha-GalCer vs. C34) alter the activation and cytotoxicity of iNKT cells against neuroblastoma in vitro. Objective 3: To analyze survival of an immunocompetent mouse model of neuroblastoma treated with C34-loaded vs alpha-GalCer-loaded CAb molecule, and to analyze the tumor microenvironment in each treatment condition. METHODS/STUDY POPULATION: CAb molecule will be generated by fusing a CD1d protein to an scFv domain for GD2 using cloning techniques. Previous work by our group has used a streptavidin-biotin system to link CD1d to an antibody against GD2, which is large and immunogenic. Protein expression of this novel fusion protein will occur in HEK293 cells. This new CAb molecule will then be loaded with alpha-GalCer or C34 for use in cytotoxicity and in vivo experiments. Cytotoxicity Assessment: Chromium assays will be used to assess the specific cytotoxicity generated by iNKT cells against neuroblastoma cells in vitro. iNKT cells will be activated by “CAb’s” with relatively high and low affinity for GD2, and also with Alpha-GalCer and C34 glycolipid antigen. flow cytometry will be used to assess for CD107a and Interferon Gamma. Mouse Model of Neuroblastoma: TH-MYCN +/+ mice will be used as an immunocompetent model of neuroblastoma. These mice have the MYCN gene under the control of a tyrosine hydroxylase promoter, and spontaneously develop neuroblastomas by 2 weeks of life which are uniformly fatal by 8 weeks of life. In vivo survival studies will be conducted by injecting CAb of relatively high and low affinity, loaded with glycolipid antigen intraperitonealy into TH-MYCN+/+ mice starting at 2 weeks of age, twice weekly. There will also be a matched negative control. Treatment groups are listed below: 1. alpha-GalCer loaded high-affinity Cab 2. alpha-GalCer loaded low-affinity Cab 3. C34-loaded high-affinity Cab 4. C34-loaded low-affinity Cab 5. Unloaded high-affinity Cab 6. Unloaded low-affinity Cab Enrollment will be 6 mice per group for the survival curves. Tumor Microenvironment analysis: 2 additional mice will be included in each group listed above to be sacrificed 2 weeks into treatment for tumor assessment with flow cytomtetry for iNKT cell, NK cell, T-Lymphocyte frequencies as well as interferon-Gamma expression. RESULTS/ANTICIPATED RESULTS: Objective 1: We expect to find that the highest affinity scFv domains for GD2 result in the greatest amount of cytotoxicity against neuroblastoma cells via iNKT cells. Objective 2: We expect that the C34 molecule will induce the greatest amounts of iNKT cell activation against neuroblastoma cells and higher cytotoxicity against neuroblastoma, which has not been shown previously. Objective 3: We expect to see prolonged survival of mice treated with the high affinity GD2 CAb loaded with C34 or alpha GalCer compared with the low affinity CAb loaded with C34 or alpha GalCer. We also expect that the C34 loaded CAb in both groups will have prolonged survival when compared with the alpha-GalCer loaded CAbs of either affinity. DISCUSSION/SIGNIFICANCE OF IMPACT: iNKT cells have been shown previously to confer an improved prognosis in neuroblastoma and other malignancies. Furthermore, high risk neuroblastomas tend to downregulate expression of a chemokine that attracts iNKT’s to the site of the neuroblastoma. Directing iNKT to the site of neuroblastoma holds promise as an effective immunotherapy option. Our preliminary data demonstrate that CAbs directed against GD2 are capable of exerting cytotoxicity of neuroblastoma in vitro. Furthermore a trend towards prolonged survival has been shown in TH-MYCN mice in early experiments. The development of a novel antibody that has reduced immunogenicity, incorporates a glycolipid antigen that does not induce iNKT cell anergy, and is specific for the GD2 tumor specific antigen has potential to result in increased iNKT-mediate neuroblastoma cytotoxicity and prolonged survival in TH-MYCN+/+ mice.

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