Abstract 4047: CD8+T cell-mediated tumor-specific induction of the NKG2D ligands to trigger NKG2D-dependent tumor cell death in vivo

2015 ◽  
Author(s):  
Jiemiao Hu ◽  
Xueqing Xia ◽  
Eugenie S. Kleinerman ◽  
Shulin Li
Keyword(s):  
Cell Death ◽  
T Cell ◽  
Tumor Cell ◽  
Cd8 T Cell ◽  
Tumor Cell Death ◽  
Nkg2d Ligands ◽  
Specific Induction

851 Potent tumor-directed T cell activation and in vivo tumor inhibition induced by a 4–1BB x 5T4 ADAPTIR™ bispecific antibody

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A904-A904
Author(s):  
Michelle Nelson ◽  
Robert Miller ◽  
Anneli Nilsson ◽  
Lill Ljung ◽  
Allison Chunyk ◽  
...  
Keyword(s):  
Cell Death ◽  
T Cell ◽  
Tumor Cell ◽  
Bispecific Antibody ◽  
Nk Cell ◽  
Cd8 T Cell ◽  
Cell Tumor ◽  
Cell Cytotoxicity ◽  
T Cell Cytotoxicity

Background4-1BB (CD137) is an activation-induced co-stimulatory receptor that regulates immune responses of activated CD8+ T cells and NK cells, by enhancing proliferation, survival, cytolytic activity and IFN-γ production. Its ability to induce potent anti-tumor CD8+ and NK cell activity makes 4-1BB an attractive target for designing novel therapeutics for immuno-oncology. However, clinical development of a monospecific 4-1BB agonistic antibody has been hampered by dose-limiting hepatic toxicities. To minimize systemic immune toxicities and enhance activity at the tumor site, we have developed a novel 4-1BB x 5T4 bispecific antibody that stimulates 4-1BB function only when co-engaged with 5T4, a tumor-associated antigen. The combined preclinical dataset presented here provides an overview of the mechanism of action and the efficacy and safety profile of ALG.APV-527, supporting its advancement into the clinic.MethodsALG. APV-527 was built based the ADAPTIR™ platform with binding domains to 4-1BB and 5T4 generated using the ALLIGATOR-GOLD® human scFv library. ALG.APV-527 was tested using primary cells in the presence or absence of cells expressing 5T4. Cell Trace-labelled PBMC sub-optimally stimulated with anti-CD3, to induce 4-1BB expression, cells were gated using flow cytometry. T cell cytotoxicity was assessed by quantifying cell death in CD8+ T cell/tumor cell co-cultures, and images were obtained using a cell live imaging system (Cytation 5). For tumor inhibition studies, human 4-1BB knock-in mice were injected subcutaneously with MB49 cells transfected with human 5T4. Cured mice were subsequently used in a toxicity study and liver pathology was evaluated.ResultsIn vitro, ALG.APV-527 enhances primary CD8+ T cell and NK cell function and proliferation in the presence of 5T4-expressing cells. Using imaging, ALG.APV-527 in combination with a bispecific T cell engager caused increased cell death in T cell/tumor cell co-cultures. ALG.APV-527 inhibited growth of established tumors at doses as low as 2 µg/mouse in a syngeneic bladder cancer model. Following recovery, mice exhibited a memory response when rechallenged with tumor. In a high dose safety study in human 4-1BB knock-in mice, ALG.APV-527 did not cause significant systemic immune activation, whereas urelumab analogue treated mice induced dermatitis, elevated serum cytokines, CD8+ T-cell liver infiltration and systemic T-cell proliferation.ConclusionsALG. APV-527 induces potent CD8+ T cell and NK cell co-stimulation and T-cell cytotoxicity and has potent in vivo anti-tumor activity, without inducing systemic toxicity. Based on preclinical data, ALG.APV-527 is a promising anti-cancer therapeutic for the treatment of a variety of 5T4-expressing solid tumors.Ethics ApprovalAll studies were review and approved by the Internal Animal Care and Use Committee (IACUC) of Aptevo Therapeutics

scholarly journals 596 Combining Bempegaldesleukin (CD122-preferential IL-2 pathway agonist) and NKTR-262 (TLR7/8 agonist) pairs local innate activation with systemic CD8+ T cell expansion to enhance anti-tumor immunity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A626-A626
Author(s):  
Annah Rolig ◽  
Daniel Rose ◽  
Grace Helen McGee ◽  
Saul Kivimae ◽  
Werner Rubas ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cycle Phase ◽  
Tumor Cell Death ◽  
Specific Immunity

BackgroundTumor cell death caused by radiation therapy (RT) can trigger anti-tumor immune responses in part because dying cells release adjuvant factors that amplify and sustain DC and T cell responses. We previously demonstrated that bempegaldesleukin (BEMPEG:NKTR-214, a first-in-class CD122-preferential IL-2 pathway agonist), significantly enhanced the anti-tumor efficacy of RT through a T cell-dependent mechanism. Because RT can induce either immunogenic or tolerogenic cell death, depending on a multitude of factors (radiation dose, cell cycle phase, and tumor microenvironment), we hypothesized that providing a specific immunogenic adjuvant, like intratumoral NKTR-262, a novel toll-like receptor (TLR) 7/8 agonist, to the tumor site would further improve systemic tumor-specific immunity by promoting synergistic activation of local immunostimulatory innate immune responses. Therefore, we evaluated whether intratumoral NKTR-262, combined with systemic BEMPEG treatment would result in improved tumor-specific immunity and survival compared to BEMPEG combined with RT.MethodsTumor-bearing mice (CT26; EMT6) received BEMPEG (0.8 mg/kg; iv), RT (16 Gy x 1), and/or intratumoral NKTR-262 (0.5 mg/kg). Flow cytometry was used to evaluate CD4+ and CD8+ T cell activation status in the blood and tumor (7 days post-treatment). The contribution of specific immune subsets was determined by depletion of CD4+, CD8+, or NK cells. CD8+ T cell cytolytic activity was determined in vitro with an Incucyte assay. Data are representative of 1–2 independent experiments (n=5–14/group) and statistical significance was determined by 1-way ANOVA (p-value cut-off of 0.05).ResultsBEMPEG/NKTR-262 resulted in significantly improved survival compared to BEMPEG/RT. Both combination therapies were CD8+ T cell dependent. However, response to BEMPEG/NKTR-262 was characterized by a significant expansion of activated CD8+ T cells (GzmA+; Ki-67+; ICOS+; PD-1+) in the blood, which correlated with reduced tumor size (p<0.05). In the tumor, BEMPEG/NKTR-262 induced higher frequencies of GzmA+ CD8+ T cells exhibiting reduced expression of suppressive molecules (PD-1+, TIM-3+), compared to BEMPEG/RT. Additionally, CD8+ T cells isolated from BEMPEG/NKTR-262-treated tumors had greater cytolytic capacity than those from BEMPEG/RT-treated mice.ConclusionsCombining BEMPEG with NKTR-262 lead to a more robust expansion of activated CD8+ T cells compared to the BEMPEG/RT combination. Enhancement of the activated CD8+ T cell response in mice treated with NKTR-262 in combination with BEMPEG suggests that intratumoral TLR stimulation provides superior antigen presentation and costimulatory activity compared to RT. A clinical trial of BEMPEG/NKTR-262 for patients with metastatic solid tumors is in progress (NCT03435640).

scholarly journals Dominant-negative ATF5 rapidly depletes survivin in tumor cells

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Xiaotian Sun ◽  
James M. Angelastro ◽  
David Merino ◽  
Qing Zhou ◽  
Markus D. Siegelin ◽  
...  
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Cancer Cells ◽  
Dominant Negative ◽  
Tumor Cell Death ◽  
Cell Penetrating ◽  
Selective Death ◽  
Tumor Types

Abstract Survivin (BIRC5, product of the BIRC5 gene) is highly expressed in many tumor types and has been widely identified as a potential target for cancer therapy. However, effective anti-survivin drugs remain to be developed. Here we report that both vector-delivered and cell-penetrating dominant-negative (dn) forms of the transcription factor ATF5 that promote selective death of cancer cells in vitro and in vivo cause survivin depletion in tumor cell lines of varying origins. dn-ATF5 decreases levels of both survivin mRNA and protein. The depletion of survivin protein appears to be driven at least in part by enhanced proteasomal turnover and depletion of the deubiquitinase USP9X. Survivin loss is rapid and precedes the onset of cell death triggered by dn-ATF5. Although survivin downregulation is sufficient to drive tumor cell death, survivin over-expression does not rescue cancer cells from dn-ATF5-promoted apoptosis. This indicates that dn-ATF5 kills malignant cells by multiple mechanisms that include, but are not limited to, survivin depletion. Cell-penetrating forms of dn-ATF5 are currently being developed for potential therapeutic use and the present findings suggest that they may pose an advantage over treatments that target only survivin.

Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid–based proteasome inhibitors

Blood ◽  
2009 ◽  
Vol 113 (23) ◽  
pp. 5927-5937 ◽  
Author(s):  
Encouse B. Golden ◽  
Philip Y. Lam ◽  
Adel Kardosh ◽  
Kevin J. Gaffney ◽  
Enrique Cadenas ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Tumor Cell ◽  
Green Tea ◽  
Boronic Acid ◽  
Proteasome Inhibitors ◽  
Green Tea Polyphenols ◽  
Tumor Cell Death

Abstract The anticancer potency of green tea and its individual components is being intensely investigated, and some cancer patients already self-medicate with this “miracle herb” in hopes of augmenting the anticancer outcome of their chemotherapy. Bortezomib (BZM) is a proteasome inhibitor in clinical use for multiple myeloma. Here, we investigated whether the combination of these compounds would yield increased antitumor efficacy in multiple myeloma and glioblastoma cell lines in vitro and in vivo. Unexpectedly, we discovered that various green tea constituents, in particular (-)-epigallocatechin gallate (EGCG) and other polyphenols with 1,2-benzenediol moieties, effectively prevented tumor cell death induced by BZM in vitro and in vivo. This pronounced antagonistic function of EGCG was evident only with boronic acid–based proteasome inhibitors (BZM, MG-262, PS-IX), but not with several non–boronic acid proteasome inhibitors (MG-132, PS-I, nelfinavir). EGCG directly reacted with BZM and blocked its proteasome inhibitory function; as a consequence, BZM could not trigger endoplasmic reticulum stress or caspase-7 activation, and did not induce tumor cell death. Taken together, our results indicate that green tea polyphenols may have the potential to negate the therapeutic efficacy of BZM and suggest that consumption of green tea products may be contraindicated during cancer therapy with BZM.

miR-15a regulation of endothelial radiation sensitivity in colorectal cancer.

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 709-709
Author(s):  
Shushan Rajesh Rana ◽  
Cristina Espinosa ◽  
Rebecca Ruhl ◽  
Latroy Robinson ◽  
Charles R. Thomas ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Death ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Background Radiation ◽  
Acid Sphingomyelinase ◽  
High Dose ◽  
Tumor Cell Death ◽  
Caspase 1

709 Background: Radiation dose escalation causes significant changes within the tumor microenvironment (TME) to enhance tumor cell death including altered microRNA (miR) levels. Among endothelial miRs, we identified miR-15a exhibits dose dependent differential regulation. miR-15a targets a key determinant of endothelial cell (EC) radiosensitivity, acid sphingomyelinase (SMPD1), an enzyme that drives rapid EC apoptosis via enhanced ceramide production. In colorectal cancer (CRC) (n = 182 patients), high miR-15a is associated with worse 5-year progression free and overall survival. miR-15a also affects immune function by promoting a pro-inflammatory TME milieu. We hypothesized miR-15a inhibition will increase tumor cell death through preservation of EC SMPD1, enhancing endothelial apoptosis and inflammatory cytokine upregulation. Methods: Using TaqMan Human miR panels, miRs were profiled in human umbilical vein ECs (HUVECs) after single 2 vs 20 Gy treatment. miR-target prediction programs identified miRs targeting SMPD1. In vitro gain and loss of function studies were performed with miR transfections in HUVECs and CT26 CRC cells. CXCL10 expression was measured by qRT-PCR. Caspase 1 activation was measured by a luminescence based assay. A CT26 syngeneic CRC flank murine model was used for in vivo miR-15a inhibitor assessment administered via tail vein injection unencapsulated or encapsulated in vascular-targeted 7C1 nanoparticles. Results: Among miRs targeting SMPD1, miR-15a exhibited the greatest differential change in HUVECs 6h post-IR between low and high dose radiation. Lower dose was associated with higher miR-15a and vice versa. Further, miR-15a levels inversely correlated with SMPD1. Exogenous miR-15a significantly decreased SMPD1 mRNA and protein. miR-15a inhibition decreased proliferation in both HUVECs and CT26 cells and increased apoptosis when combined with radiation. miR-15a inhibition increased endothelial CXCL10 expression and caspase-1 activation. Both systemic and vascular-targeted miR-15a inhibitor significantly diminished tumor growth in vivo. Conclusions: Our data suggests inhibition of vascular miR-15a is sufficient to decrease tumor growth likely due to rescue of endothelial SMPD1.

Proteomic characterization of EL4 lymphoma-derived tumors upon chemotherapy treatment reveals potential roles for lysosomes and caspase-6 during tumor cell death in vivo

PROTEOMICS ◽  
2017 ◽  
Vol 17 (12) ◽  
pp. 1700060 ◽  
Author(s):  
David A. Kramer ◽  
Mohamed A. Eldeeb ◽  
Melinda Wuest ◽  
John Mercer ◽  
Richard P. Fahlman
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Chemotherapy Treatment ◽  
Tumor Cell Death ◽  
Caspase 6

scholarly journals Ionizing radiation improves RIG-I mediated immunotherapy through enhanced p53 activation in malignant melanoma

2021 ◽  
Author(s):  
Silke Lambing ◽  
Stefan Holdenrieder ◽  
Patrick Müller ◽  
Christian Hagen ◽  
Stephan Garbe ◽  
...  
Keyword(s):  
Cell Death ◽  
Malignant Melanoma ◽  
Tumor Cell ◽  
Low Dose ◽  
Immune Cell ◽  
Cytotoxic T Cell ◽  
Great Promise ◽  
Type I ◽  
Tumor Cell Death

The activation of the innate immune receptor RIG-I is a promising approach in immunooncology and currently under investigation in clinical trials. RIG-I agonists elicit a strong immune activation in both tumor and immune cells and induce both direct and indirect immune cell-mediated tumor cell death which involves tumor-specific cytotoxic T-cell response and type I interferon-driven innate cytotoxic immunity. Besides RIG-I, irradiation is known to induce cytotoxic DNA damage resulting in tumor debulking followed by the induction of tumor-specific immunity. To date, it is unclear whether the molecular antitumor effects of RIG-I and irradiation are additive or even synergize. Here, we investigated the combination of RIG-I activation with radiotherapy in melanoma. We found that low dose x-ray irradiation enhanced the extent and immunogenicity of RIG-I mediated tumor cell death in human and murine melanoma cell lines and in the murine B16 melanoma model in vivo. Pathway analysis of transcriptomic data revealed a central role for p53 downstream of the combined treatment, which was corroborated using p53-/- B16 cells. In vivo, the additional effect of irradiation on immune cell activation and inhibition of tumor growth was lost in mice carrying p53-knockout B16 tumors, while the response to RIG-I stimulation in those mice was maintained. Thus, our results identify p53 as pivotal for the synergy of RIG-I with irradiation, resulting in potent induction of immunogenic tumor cell death. Consequently, low dose radiotherapy holds great promise to further improve the efficacy or RIG-I ligands especially in patients with malignant melanoma or other tumors exhibiting a functional p53 pathway.

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