scholarly journals Tumor-specific EphA2 receptor tyrosine kinase inhibits anti-tumor immunity by recruiting suppressive myeloid populations in NSCLC

2020 ◽  
Author(s):  
Eileen Shiuan ◽  
Wenqiang Song ◽  
Shan Wang ◽  
Dana M. Brantley-Sieders ◽  
Jin Chen
Keyword(s):  
T Cells ◽  
Tyrosine Kinase ◽  
Tumor Immunity ◽  
Receptor Tyrosine Kinase ◽  
Lung Tumor ◽  
Host Immune System ◽  
Tumor Immune Escape ◽  
Arginase 1

AbstractGiven the success of both targeted and immunotherapies against cancer, there is increasing utility for identifying targeted agents that also promote anti-tumor immunity. EphA2 is a receptor tyrosine kinase that contributes to tumor growth and metastasis and has been identified as a viable target for many solid cancers. Investigating EphA2’s impact on the host immune system may advance our understanding of tumor immune evasion and the consequences of targeting EphA2 on the tumor microenvironment. Here, we examine how tumor-specific EphA2 affects the activation and infiltration of immune cell populations and the cytokine and chemokine milieu in non-small cell lung cancer (NSCLC). Effects of EphA2 overexpression in murine NSCLC cells were evaluated in both in vitro cell viability assays and in vivo tumor models. Tumor immune infiltrate was assessed by flow cytometry. Cytokine and chemokine expression was evaluated using NanoString technology and qRT-PCR. Although EphA2 overexpression in NSCLC cells did not display proliferative advantage in vitro, it conferred a growth advantage in vivo. Analysis of lung tumor infiltrate revealed decreased natural killer and T cells in the EphA2-overexpressing tumors, as well as increased myeloid populations, including tumor-associated macrophages (TAMs). T cell activation, particularly in CD8 T cells, was decreased, while PD-1 expression was increased. These changes were accompanied by increased monocyte-attracting chemokines, specifically CCL2, CCL7, CCL8, and CCL12, and immunosuppressive proteins TGF-β and arginase 1. Our studies suggest EphA2 on tumor cells recruits monocytes and promotes their differentiation into TAMs that likely inhibit activation and infiltration of cytotoxic lymphocytes, promoting tumor immune escape. Further studies are needed to determine the molecular mechanisms by which EphA2 affects the recruitment of these cell types and to test the function of these myeloid cells.

scholarly journals 114 Preclinical development of a novel iPSC-derived CAR-MICA/B NK cell immunotherapy to overcome solid tumor escape from NKG2D-mediated mechanisms of recognition and killing

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A126-A126
Author(s):  
John Goulding ◽  
Mochtar Pribadi ◽  
Robert Blum ◽  
Wen-I Yeh ◽  
Yijia Pan ◽  
...  
Keyword(s):  
T Cells ◽  
Cancer Immunotherapy ◽  
Tumor Immunity ◽  
Immune Cell ◽  
Nk Cell ◽  
Tumor Escape ◽  
Car T Cells ◽  
Car T

BackgroundMHC class I related proteins A (MICA) and B (MICB) are induced by cellular stress and transformation, and their expression has been reported for many cancer types. NKG2D, an activating receptor expressed on natural killer (NK) and T cells, targets the membrane-distal domains of MICA/B, activating a potent cytotoxic response. However, advanced cancer cells frequently evade immune cell recognition by proteolytic shedding of the α1 and α2 domains of MICA/B, which can significantly reduce NKG2D function and the cytolytic activity.MethodsRecent publications have shown that therapeutic antibodies targeting the membrane-proximal α3 domain inhibited MICA/B shedding, resulting in a substantial increase in the cell surface density of MICA/B and restoration of immune cell-mediated tumor immunity.1 We have developed a novel chimeric antigen receptor (CAR) targeting the conserved α3 domain of MICA/B (CAR-MICA/B). Additionally, utilizing our proprietary induced pluripotent stem cell (iPSC) product platform, we have developed multiplexed engineered, iPSC-derived CAR-MICA/B NK (iNK) cells for off-the-shelf cancer immunotherapy.ResultsA screen of CAR spacer and ScFv orientations in primary T cells delineated MICA-specific in vitro activation and cytotoxicity as well as in vivo tumor control against MICA+ cancer cells. The novel CAR-MICA/B design was used to compare efficacy against NKG2D CAR T cells, an alternative MICA/B targeting strategy. CAR-MICA/B T cells showed superior cytotoxicity against melanoma, breast cancer, renal cell carcinoma, and lung cancer lines in vitro compared to primary NKG2D CAR T cells (p<0.01). Additionally, using an in vivo xenograft metastasis model, CAR-MICA/B T cells eliminated A2058 human melanoma metastases in the majority of the mice treated. In contrast, NKG2D CAR T cells were unable to control tumor growth or metastases. To translate CAR-MICA/B functionality into an off-the-shelf cancer immunotherapy, CAR-MICA/B was introduced into a clonal master engineered iPSC line to derive a multiplexed engineered, CAR-MICA/B iNK cell product candidate. Using a panel of tumor cell lines expressing MICA/B, CAR-MICA/B iNK cells displayed MICA specificity, resulting in enhanced cytokine production, degranulation, and cytotoxicity. Furthermore, in vivo NK cell cytotoxicity was evaluated using the B16-F10 melanoma cell line, engineered to express MICA. In this model, CAR-MICA/B iNK cells significantly reduced liver and lung metastases, compared to untreated controls, by 93% and 87% respectively.ConclusionsOngoing work is focused on extending these preclinical studies to further support the clinical translation of an off-the-shelf, CAR-MICA/B iNK cell cancer immunotherapy with the potential to overcome solid tumor escape from NKG2D-mediated mechanisms of recognition and killing.ReferenceFerrari de Andrade L, Tay RE, Pan D, Luoma AM, Ito Y, Badrinath S, Tsoucas D, Franz B, May KF Jr, Harvey CJ, Kobold S, Pyrdol JW, Yoon C, Yuan GC, Hodi FS, Dranoff G, Wucherpfennig KW. Antibody-mediated inhibition of MICA and MICB shedding promotes NK cell-driven tumor immunity. Science 2018 Mar 30;359(6383):1537–1542.

scholarly journals 323 Immunogenic syngeneic model MC38-OVA for the preclinical evaluation of immune evasion and checkpoint blockade

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A348-A348
Author(s):  
Jessie Wang ◽  
Kaixia Lian ◽  
Jia Zheng ◽  
Chenpan Nie ◽  
Annie An ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Immunity ◽  
Immune Evasion ◽  
Syngeneic Mouse ◽  
Ifn Γ ◽  
Draining Lymph Nodes ◽  
Syngeneic Tumors

BackgroundThe development of immuno-oncology (I/O) therapeutics has revolutionized the cancer treatment landscape. Despite this achievement, the mechanism behind limited responses is poorly understood. Tumor immune evasion has been reported to arise through the loss of tumor necrosis factor (TNF) signaling, interferon-γ (IFN-γ) signaling, and antigen presentation pathways, which are crucial to CD8+ T cell-mediated killing. Syngeneic mouse models have been widely used as they have an intact immune system, are easily accessible, and have a vast array of historical data for comparison. However, limited syngeneic models respond to immune checkpoint inhibitors, possibly due to low intrinsic immunogenicity. The expression of ovalbumin (OVA) has previously shown to sufficiently alter the susceptibility of syngeneic tumors to host T cell-mediated responses. In this study, the newly developed OVA-expressing MC38 syngeneic line was characterized for tumor immunity, checkpoint blockade response and response durability.MethodsMurine colon cancer MC38 cells were transduced by lentiviral vector with chicken OVA coding cDNA. A single clone was selected, and OVA expression was confirmed by western blot. The MC38-OVA cells were subcutaneously implanted into immunocompetent mice to evaluate the tumorigenicity and in vivo response to anti-PD-1 antibody treatment. Blood was collected 2 days post final dose of anti-PD-1 treatment for phenotypic analysis by FACS. Spleen and tumor draining lymph nodes were collected at termination for FACS analysis of IFN-γ+ T cells and OVA specific CD8+ T cells. Adoptive transfer was evaluated by challenge studies in both MC38-OVA and MC38 tumor-bearing mice with T cells derived from MC38-OVA mice, anti-PD-1 cured mice and OT-I mice. In vitro killing assays were performed to evaluate the function of adoptive CD3+ T cells transfer.ResultsOVA-expressing MC38 presented complete regression under anti-PD-1 treatment in vivo. T cell expansion was observed after anti-PD-1 treatment in peripheral blood with increased IFN-γ+ T cells in both tumor-draining lymph nodes and spleen. Additionally, anti-PD-1 cured mice generated robust tumor specific memory T cell, which successfully inhibited MC38-OVA and MC38 tumor growth following adoptive transfer. CD3+ T cells from MC38-OVA-bearing mice and OT-I mice showed anti-tumor immunity in vivo. In vitro killing assay demonstrated increased immunity.ConclusionsSyngeneic mouse tumor models are preferred preclinical models for I/O research, despite limited intrinsic immunogenicity. OVA expression in syngeneic tumors largely increased T cell-mediated immunity to enhance antigen-specific T cell responses during tumorigenesis, providing novel immunogenic models for preclinical immunotherapy evaluation.

The Multi-Targeted Receptor Tyrosine Kinase Inhibitor, ABT-869, Induces Apoptosis of AML Cells Both In Vitro and In Vivo.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 616-616 ◽  
Author(s):  
Deepa B. Shankar ◽  
Jenny C. Chang ◽  
Bertrand Parcells ◽  
Salemiz Sandoval ◽  
Junling Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tyrosine Kinase ◽  
Cell Line ◽  
Progenitor Cells ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Scid Mice ◽  
Parp Cleavage

Abstract Children with acute myeloid leukemia (AML) have less than 60% overall survival despite aggressive chemotherapy and bone marrow transplantation. Only one third of the adult patients diagnosed with AML will be cured. AML blast cells from up to 30% of patients express a constitutively active receptor tyrosine kinase, FLT3-ITD, which contains an internal tandem duplication in the juxtamembrane domain. Patients with FLT3-ITD have a worse prognosis. ABT-869 is a novel multi-targeted small molecule inhibitor of receptor tyrosine kinases and is a potent inhibitor of FLT3, c-Kit, and all members of the VEGF and PDGF receptor families. To determine the effects of ABT-896 on AML cells, we treated AML cell lines, primary cells, and tumors in xenograft models with varying concentrations of the drug. In vitro viability assays showed that ABT-869 inhibited the growth of two different cell lines, MV-4-11 (human AML cell line that expresses FLT3-ITD) and BAF3-ITD (murine B-cell line stably transfected with the FLT3-ITD) at an IC50 of 10nM. ABT-869 was also effective against another mutation of FLT3, D835V, but at higher concentrations (IC50 of 100nM). Phosphorylation of FLT3 and activation of downstream signaling molecules, STAT5 and ERK, were inhibited by ABT-869 in a concentration-dependent manner. Cells were also stained with Annexin V-FITC and Propidium Iodide, and analyzed using FACS. ABT-869 induced apoptosis, caspase-3 activation, and PARP cleavage after 48 hours. To examine the in vitro effects of ABT-869 on normal hematopoietic progenitor cells, we performed methylcellulose-based colony assays with human bone marrow. No significant difference was observed in the number and type of colonies formed using BM cells treated with ABT-869 or control, up to a concentration of 1 micromolar. These results suggest that ABT-869 is not toxic to normal bone marrow progenitor cells at concentrations that are effective against AML cells. To examine the effects of ABT-869 in vivo, we treated SCID mice injected with MV-4-11, Baf3-ITD, Baf3-D835V, or Baf3-WT cells, with oral preparations of ABT-869. Complete regression of MV-4-11 tumors was observed in mice treated with ABT-869 at 20 and 40 mg/kg/day. No adverse effects were detected in the peripheral blood counts, bone marrow, spleen or liver. Histology of the tumors from the control-treated group showed a high degree of proliferation by Ki-67 staining, increased mitotic figures, and a well-defined tumor mass. In contrast, the tumors from mice treated with ABT-869 showed a number of apoptotic bodies by TUNEL staining and the presence of reactive, inflammatory cells. Interestingly, we also observed that mice that received ABT-869 the day after injection of AML cells remained tumor-free for over 2 months in contrast to the mice receiving the vehicle alone. Inhibition of FLT3 phosphorylation was demonstrated in the tumors from mice treated with ABT-869. We are evaluating the activity of ABT-869 treatment of SCID mice injected with Baf3-ITD, Baf3-D835V, or Baf3-WT cells. NOD-SCID mouse models are currently being used to analyze the effects of ABT-869 on primary AML cells in vivo. Our preclinical studies demonstrate that ABT-869 is effective and nontoxic, and provide rationale for the treatment and prevention of relapse in AML patients.

Preclinical Testing of a Novel Axl-Kinase Inhibitor in Chronic Lymphocytic Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1799-1799
Author(s):  
Maria Göbel ◽  
Michael Möllmann ◽  
Andre Görgens ◽  
Ulrich Dührsen ◽  
Andreas Hüttmann ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Cell Polarization ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Blue Staining ◽  
Nsg Mice

Abstract Abstract 1799 The receptor tyrosine kinase Axl belongs to the TAM (Tyro-3, Axl and Mer) family and is involved in the progression of several human malignancies including chronic lymphocytic leukemia (CLL), where it is has been found to be overexpressed in comparison to normal B-cells. An increasing body of evidence suggests that Axl acts as an oncogene which increases the survival, proliferation, metastatic potential and chemotherapy resistance of tumor cells. Hence, it has been recently identified as a potential therapeutic target in a wide range of tumor entities with deregulated Axl expression including prostate cancer, glioma, lung cancer and CLL. Here, we investigated two different Axl inhibitors for their potential to inhibit the migratory capacity and survival of leukemic cells in preclinical CLL models. In vitro studies: Freshly isolated PBMC (>90% CD5+CD19+) from CLL patients were incubated in serum free medium for 48h containing concentrations series of 2 different Axl inhibitors: BMS777607, a previously published inhibitor of the MET kinase family, and LDC2636, a novel inhibitor of the TAM receptor tyrosine kinase (RTK) family with high affinity to Axl. Viability of CLL cells was assessed by trypan blue staining and flow cytometry employing annexin V staining. Since a polarized phenotype is required for migration, cell polarization was analyzed by time-lapse video-microscopy. We detected cytotoxic effects in a patient dependent manner that were more prevalent in LDC2636 as compared to BMS777607 treated cells (LD50= 1.4 μM vs. 5.2 μM, p<0.004, n=5). Cell polarization of the remaining viable cells was significantly reduced in a dose dependent fashion in comparison to vehicle only controls (LDC2636 IC50 = 7.2 μM, p<0.00001; BMS777607: IC50=6.2μM; p=0.0004). Of note, both Axl inhibitors exhibited significantly weaker effects on both, the viability and cell polarization of normal PBMC over the whole concentration range tested (p<0.05, n=5). In vivo studies: To verify our hypothesis that reduced cell polarization results in decreased homing of leukemic cells in vivo we employed a recently developed adoptive transfer model of CLL. In this model NOD/SCID/gcnull(NSG) mice were pre-treated with a single intraperitoneal bolus of LDC2636 or BMS777607 (20 mg/kg) and subsequently transplanted with primary CLL cells. Both Axl inhibitors significantly reduced the homing capacity of CLL cells to the bone marrow of NSG mice by 43% and 59%, respectively, compared to vehicle treated controls (LDC2636: p=0.046, BMS777607 p=0.0077; n=3). These data demonstrate that Axl inhibitors exert potent in vitro and in vivo activity against human CLL cells, which is caused at least in part by the suppression of CLL homing to their supportive stromal niches. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Receptor Tyrosine Kinase RON and Its Isoforms as Therapeutic Targets in Ewing Sarcoma

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 904
Author(s):  
Philipp Berning ◽  
Carolin Hennemann ◽  
Claudia Tulotta ◽  
Christiane Schaefer ◽  
Birgit Lechtape ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Ewing Sarcoma ◽  
Dna Methyltransferase ◽  
Short Form ◽  
Metastatic Progression ◽  
Zebrafish Model ◽  
Resistance To Insulin

The receptor tyrosine kinase (RTK) RON is linked to an aggressive metastatic phenotype of carcinomas. While gaining interest as a therapeutic target, RON remains unstudied in sarcomas. In Ewing sarcoma, we identified RON among RTKs conferring resistance to insulin-like growth factor-1 receptor (IGF1R) targeting. Therefore, we explored RON in pediatric sarcoma cell lines and an embryonic Tg(kdrl:mCherry) zebrafish model, using an shRNA-based approach. To examine RON–IGF1R crosstalk, we employed the clinical-grade monoclonal antibody IMC-RON8, alone and together with the IGF1R-antibody IMC-A12. RON silencing demonstrated functions in vitro and in vivo, particularly within micrometastatic cellular capacities. Signaling studies revealed a unidirectional IGF1-mediated cross-activation of RON. Yet, IMC-A12 failed to sensitize cells to IMC-RON8, suggesting additional mechanisms of RON activation. Here, RT-PCR revealed that childhood sarcomas express short-form RON, an isoform resistant to antibody-mediated targeting. Interestingly, in contrast to carcinomas, treatment with DNA methyltransferase inhibitor did not diminish but increased short-form RON expression. Thus, this first report supports a role for RON in the metastatic progression of Ewing sarcoma. While principal molecular functions appear transferrable between carcinomas, Ewing sarcoma and possibly more common sarcoma subtypes, RON highlights that specific regulations of cellular networks and isoforms require better understanding to successfully transfer targeting strategies.

The Potential of T Cell Immunoglobulin and Mucin-Domain containing-3 (Tim-3) in Designing Novel Immunotherapy for Bladder Cancer

2021 ◽  
Vol 21 ◽  
Author(s):  
Monireh Mohsenzadegan ◽  
Parizad Bavandpour ◽  
Mohammad Reza Nowroozi ◽  
Erfan Amini ◽  
Masoumeh Kourosh-Arami ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
T Cells ◽  
T Cell ◽  
Tumor Immunity ◽  
Checkpoint Inhibitors ◽  
Number Of Patients ◽  
Anti Cancer ◽  
Domain 3

: Targeting inhibitory receptors on T cells in the tumor sites can promote effective anti-tumor immunity in bladder cancer. Unfortunately, the main dilemma is that a large number of patients remain refractory to CTLA-4, PD-1, and PD-L1 blockade therapies. T-cell immunoglobulin and mucin domain 3 (Tim-3) is an inhibitory receptor expressed on T cells and innate immune cells. Both in vivo and in vitro data from patients with advanced cancers support the role of Tim-3 inhibition in satisfactory anti-tumor immunity. In bladder cancer, the expression level of Tim-3 significantly increases with advanced pathological grade and T stage. Therefore, rationality implies that designing novel monoclonal antibodies reactive with Tim-3 alone or in combination with other checkpoint inhibitors may indicate a favorable response in bladder cancer. Here, we aimed to investigate the possibility of targeting Tim-3 as a novel anti-cancer treatment for bladder cancer.

Oligomerization of the extracellular domain of Boss enhances its binding to the Sevenless receptor and its antagonistic effect on R7 induction

1998 ◽  
Vol 111 (6) ◽  
pp. 737-747 ◽  
Author(s):  
E.A. Sevrioukov ◽  
J.H. Walenta ◽  
A. Sunio ◽  
M. Phistry ◽  
H. Kramer
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Compound Eye ◽  
Transmembrane Domain ◽  
Extracellular Domain ◽  
Antagonistic Effect ◽  
Lac Repressor ◽  
Receptor Complexes

In the developing compound eye of Drosophila, neuronal differentiation of the R7 photoreceptor cell is induced by the interaction of the receptor tyrosine kinase Sevenless with its ligand Bride of sevenless (Boss), which is expressed on the neighboring R8 cell. Boss is an unusual ligand of a receptor tyrosine kinase: it is composed of a large extracellular domain, a transmembrane domain with seven membrane-spanning segments and a cytoplasmic tail. Expression of a monomeric, secreted form of the extracellular domain of Boss is not sufficient for Sevenless activation, and instead acts as a weak antagonist. Because oligomerization appears to be a critical step in the activation of receptor tyrosine kinases, we used oligomerized forms of the Boss extracellular domain to test their ability to bind to Sevenless in vivo and restore R7 induction in vivo. Oligomerization was achieved by fusion to the leucine zipper of the yeast transcription factor GCN4 or to the tetramerization helix of Lac repressor. Binding of these multivalent proteins to Sevenless could be detected in vitro by immunoprecipitation of cross-linked ligand/receptor complexes and in vivo by receptor-dependent ligand localization. However, neither R8-specific or ubiquitous expression of multivalent Exboss ligands rescued the boss phenotype. Instead, these ligands acted as competitive inhibitors for wild-type Boss protein and thereby suppressed R7 induction. Therefore the role of the transmembrane or cytoplasmic domains of Boss in the activation of the Sev receptor cannot be replaced by oligomerization.

Inhibiting the IGF-1 Receptor Tyrosine Kinase with Picropodophillin: An In Vitro and In Vivo Study in the 5T33MM Mouse Model.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 640-640
Author(s):  
Karin Vanderkerken ◽  
Eline Menu ◽  
Thomas Stromberg ◽  
Hendrik De Raeve ◽  
Kewal Asosingh ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Mouse Model ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Microvessel Density ◽  
Kinase Inhibitor ◽  
High Dose

Abstract Multiple myeloma (MM) represents a B-cell malignancy, characterized by monoclonal proliferation of plasma cells in the bone marrow (BM) and is associated with osteolysis and angiogenesis. Insulin-like growth factor-1 (IGF-1), produced by the BM stromal cells, has been described as an important factor in the survival, proliferation and migration of MM cells. The latter process is involved in the homing of the MM cells to the BM. IGF-1 also induces VEGF secretion by the MM cells, thus stimulating angiogenesis in the BM. As IGF-1 is a pleiotropic factor in MM, therapeutic strategies targeting the IGF-1R may be effective as anti-tumor treatments. In this work we investigated the effect of an IGF-1 receptor tyrosine kinase inhibitor (picropodophyllin or PPP1) in the murine, syngeneic 5T33MM model of multiple myeloma. This mouse model is representative for the human disease and can combine in vitro and in vivo studies. We first investigated the effects of PPP on the MM cells in vitro. We and others have previously demonstrated that IGF-1 induced ERK activation, involved in VEGF secretion and proliferation. When the 5T33MM cells were preincubated with 1microM PPP, Western blot analysis demonstrated the blocking of this activation. Furthermore, when the 5T33MM cells were preincubated with PPP for 30 min, IGF-1 induced VEGF secretion and proliferation of the 5T33MM cells were completely blocked. Next, we used the tyrosine kinase inhibitor PPP in vivo. 5T33MM cells were injected intravenously in C57BLKaLwRij mice and the development of the disease was monitored by measuring the serum paraprotein concentration. Mice were either treated with a low (17mM, IP, twice a day) or a high dose of PPP (50mM, IP, twice a day) or with the vehicle (DMSO/oil 9/1) from the day of injection with 5T33MM onward. At week 3, vehicle controls showed signs of morbidity and were sacrificed. The presence of tumor was measured by assessing serum paraprotein concentrations and determining the proportion of idiotype positive cells in the BM by flow cytometry. Angiogenesis was assessed by measuring the microvessel density on CD31 stained paraffin sections. The tumor burden in the bone marrow in the PPP treated mice was 77% lower than in vehicle treated animals (p< 0,0001) and the serum paraprotein concentration was 90% lower (p< 0,0001). The microvessel density in the BM of the PPP treated group was reduced by 60% (p< 0,02). In a separate survival experiment the mice were either treated with the vehicle or with the high dose (50mM) of PPP, from the time of tumor injection. Kaplan-Meier analysis demonstrated a significant increase in survival after treatment with PPP when compared with vehicle (28 vs. 18 days, p<0,001). These data demonstrate that the IGF-1RTK inhibitor PPP possesses strong anti-tumor activity, as demonstrated both in vitro and in vivo in a syngeneic model of multiple myeloma, and may therefore be an effective therapeutic candidate for MM treatment.

Multi-Targeted Receptor Tyrosine Kinase Inhibitor, ABT-869, Induces Apoptosis and Suppresses Proliferation of Ba/F3 FLT-3 ITD Mutant Cells in Vitro and in Vivo through Inhibition of FLT3 and AKT.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1938-1938
Author(s):  
Jenny E Hernandez ◽  
Joan Zape ◽  
Keith Glaser ◽  
Elliot Landaw ◽  
Cecilia Fu ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Mutant Cell ◽  
Vehicle Control ◽  
Ic50 Value ◽  
Mutant Cells

Abstract FLT3 is a receptor tyrosine kinase of the subclass III family that plays a vital role in the regulation of differentiation, proliferation and survival of normal hematopoietic cells. FLT3 mutations are often found in patients with acute myelogenous leukemia (AML) and confer a poor prognosis. Of these mutations, 15–35% are FLT3 ITD (internal tandem duplication) mutations and 5–7% are point mutations in the FLT3 kinase activation loop, e.g. D835V. We are studying the signaling pathways associated with a small molecule multi-targeted receptor tyrosine kinase inhibitor (RTKI), ABT-869. To determine the effects of ABT-869 in vitro and in vivo, a Ba/F3 mouse pro-B lymphocytic cell line harboring the FLT-3 ITD or FLT-3 D835V mutation was used as an isolated FLT-3 mutant model system. In vitro, ABT-869 is effective in inhibiting the proliferation of Ba/F3 Flt-3 ITD mutant cells (IC50 value of 1 nM) when compared to Ba/F3 Flt-3 D835V mutant (IC50 value between 1 and 10 μM) and Ba/F3 Flt-3 wildtype (WT) cells (IC50 value of 10 μM). Annexin V and propidium iodide staining of cells revealed that an increase in apoptosis occurred in Ba/F3 Flt-3 ITD mutant cells treated with 1μM ABT-869 for 24 hours (42.8%) when compared to untreated (4.7%) or vehicle control (4.0%) cells. Ba/F3 Flt-3 D835V mutant cell lines demonstrated a 12.5% rate of apoptosis at 1μM, compared to untreated (1.99%) and vehicle control (2.1%) cell lines. Propidium iodide staining of treated Ba/F3 Flt-3 WT cell lines revealed no difference in apoptosis when compared to untreated Ba/F3 Flt-3 WT cells or DMSO controls. PARP cleavage was observed in Ba/F3 FLT-3 ITD mutant cells, following 6 hours of treatment with 1 to 100 nM ABT-869, whereas no cleavage was observed in Ba/F3 WT cells treated with ABT-869. To study the effects of ABT-869 in vivo, we treated SCID mice injected with Ba/F3 Flt-3 ITD, Ba/F3 Flt-3 D835V, or Ba/F3 Flt-3 WT cells and monitored disease progression using bioluminescence imaging. The mice injected with the Ba/F3 FLT-3 ITD mutant cells and treated with vehicle control developed metastases and had a median survival time of 2 weeks. In contrast, the ABT-869 treated group had slower disease progression with median survival of 6.2 weeks (P&lt;0.008). Both control and treated mice injected with Ba/F3 FLT-3 D835V mutant cell lines developed metastases and had similar survival (median 1.7 and 1.9 weeks, respectively). Survival times of control and treated mice injected with Ba/F3 FLT-3 WT cells were also similar (median 8.4 and 8.1 weeks, respectively). Previous work identified that ABT-869 induced apoptosis of acute myeloid leukemia cells through inhibition of FLT-3 reception phosphorylation, which is observed as early as 3 hours after treatment. In Ba/F3 cells expressing FLT-3 ITD, ABT-869 also inhibited phosphorylation of AKT, which is upstream of the pro-apoptotic protein Bad. Therefore, our preclinical data suggest that ABT-869 induces apoptosis of FLT-3 ITD mutant cells both in vitro and in vivo. These studies provide rationale for the treatment of acute leukemia patients harboring the FLT3-ITD mutation with ABT-869 and the potential benefit of combining small molecule inhibitors that target both RTKs and AKT.

Bone Marrow Myeloid-Derived Suppressor Cells (MDSC) Inhibit Graft Versus Host Disease (GVHD) Via An Arginase-1 Dependant Mechanism That Is Upregulated by IL-13

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 241-241
Author(s):  
Steven L Highfill ◽  
Paulo Rodriguez ◽  
Qing Zhou ◽  
Christine A Goetz ◽  
Rachelle Veenstra ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
State University ◽  
Medical College ◽  
Louisiana State University ◽  
Arginase 1 ◽  
University Patents ◽  
Donor T Cells

Abstract Abstract 241 Background: Myeloid-derived suppressor cells (MDSC) are a well-defined population of cells that accumulate in the tissue of tumor-bearing animals and are known to inhibit immune responses. Here, we have developed a novel method by which we can generate MDSC from the BM of wild type mice. Our goals were to determine the effectiveness of these cells in inhibiting an allogeneic T-cell reaction, the mechanism by which this occurs, and the impact on the graft-versus-tumor (GVT) activity of donor T-cells. Results: Our results show that the incubation of WT BM with G-CSF and GM-CSF for a period of 4 days results in a population of cells predominately co-expressing CD11b and Gr1 (50%). Most of these cells have a monocytic phenotype of Ly6GloLy6C+ (73%) and also express other markers associated with MDSCs such as IL4Ra (64%), F4/80 (63%) and CD115 (43%). Such MDSC potently inhibited in vitro allogeneic T-cell responses and the addition of IL-13 to the MDSC culture enhanced their suppressive capacity (60% suppression by MDSC at the peak of the response, day 5 vs. 75% suppression by MDSC-IL13, P<0.001). Suppression was dependent on L-arginine depletion because only the addition excess L-arginine, but not tryptophan, resulted in a significant reduction in suppression (60% reduction at day 4, P=0.001). Adding IL-13 to the MDSC cultures resulted in arginase-1 upregulation (20 fold increase in expression over control BM for MDSC vs. 350 fold increase in MDSC-IL13, P<0.001). The arginase inhibitor, nor-NOHA, significantly reduced MDSC suppression in vitro. GNC2 kinase knockout T cells were resistant to suppression, consistent with their inability to sense L-arginine depletion. Although iNOS was upregulated 5-fold in MDSCs vs BM, IL13 addition did not further upregulate iNOS. Suppression was mostly contact-independent. In vivo, MDSC-IL13 derived from GFP transgenic BM migrated to sites of allopriming. MDSC-IL13 from luciferase transgenic donors increased over a 3 week period of time as assessed by bioluminescent imaging. Although both MDSC and MDSC-IL13 inhibited GVHD lethality, MDSC-IL13 were more effective at enhancing survival (MDSC vs. MDSC-IL13, P=0.001). When compared with untreated mice, GVHD inhibition in MDSC-IL13 treated mice was associated with: 1) Limited donor T-cell proliferation (CD4+CFSE−, 40% vs. 17%, P=0.01; CD8+CFSE−, 51% vs. 16%, P=0.01); 2) Decreased donor T-cell activation (CD4+CD62L−, 74% vs. 50%, P<0.001; CD8+CD62L−, 77% vs. 41%, P<0.001); 3) Decreased proinflammatory cytokine production (CD4+IFNg+, 37% vs. 24%, P=0.04; CD8+IFNg+, 30% vs. 15%, P=0.007); 4) Decreased expression of intracellular CD3z chain (CD4+CD3z+, 86% vs. 56%, P<0.001; CD8+CD3z+, 85% vs. 68%, P<0.001). On day 14, donor MDSC-IL13 cells, distinguishable from donor BM and the host by a CD45 congenic marker, were re-isolated from the spleen of murine GVHD recipients. MDSC-IL13 cells retained their initial phenotype and were potent ex vivo suppressors of an allogeneic T cell response. Arginase-1 knockout MDSC-IL13 did not have a significant effect on reducing GVHD, indicating that arginase-1 expression was vital to the in vivo suppressive effect of MDSCs. MDSC-IL13 did not abrogate the graft-versus-tumor effect of donor T-cells. In MDSC-IL13 treated mice, donor T-cells retained their ability to eliminate A20 lymphoma cells, and at the same time, had improved survival when compared to mice receiving A20 cells plus T-cells all of which succumbed to GVHD (BM+T+A20 vs. BM+T+A20+MDSC-IL13, P<0.001). Since arginase-1 expression was critical for suppression, we exploited this mechanism of action by administering a pegylated form of human arginase-1 (PEG-arg1) to systemically deplete L-arginine. We find that GVHD survival is significantly improved (BM+T vs. BM+T+PEG-arg1, P=0.003). Conclusions: We can conclude that BM-derived MDSC-IL13 have the ability to dampen GVHD and enhance survival when using a fully-mismatched murine model of BMT. Arginase-1 expression was found to play a critical role in MDSC-mediated suppression. A GVT effect was not ablated by MDSC-IL13. In vivo administration of PEG-arg1 resulted in L-arginine depletion and significant GVHD reduction. Both MDSC infusion and PEG-arg1 administration are promising strategies that warrant further preclinical studies to prevent GVHD that may be readily translatable in the clinic. Disclosures: Highfill: UIniversity of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties. Rodriguez:University of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties. Ochoa:University of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties. Blazar:University of Minnesota: Patents & Royalties; Louisiana State University: Patents & Royalties; Medical College of Georgia: Patents & Royalties.

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