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

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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Combined Inhibition of Chk1 and MEK1/2 Leads to Tumor Cell Death In Vivo

10.21236/ada446698 ◽

2005 ◽

Author(s):

Paul Dent

Keyword(s):

Cell Death ◽

Tumor Cell ◽

Tumor Cell Death

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

10.1158/1538-7445.am2015-4047 ◽

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

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Dominant-negative ATF5 rapidly depletes survivin in tumor cells

Cell Death and Disease ◽

10.1038/s41419-019-1872-y ◽

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.

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

Blood ◽

10.1182/blood-2008-07-171389 ◽

2009 ◽

Vol 113 (23) ◽

pp. 5927-5937 ◽

Cited By ~ 158

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.

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Obinutuzumab (GA101) More Potently Engages Phagocytic-Lineage Cells Resulting In Enhanced Monocyte and Macrophage Activity When Compared To Rituximab and Ofatumumab

Blood ◽

10.1182/blood.v122.21.5136.5136 ◽

2013 ◽

Vol 122 (21) ◽

pp. 5136-5136 ◽

Cited By ~ 2

Author(s):

Sylvia Herter ◽

Christian Klein ◽

Pablo Umana ◽

Marina Bacac

Keyword(s):

Cell Death ◽

Tumor Cell ◽

Nk Cell ◽

Antibody Activity ◽

Type I ◽

Type Ii ◽

Therapeutic Antibodies ◽

Tumor Cell Death ◽

Macrophage Activity ◽

Anti Cd20

Abstract Therapeutic antibodies possess several clinically relevant mechanisms of action including cell death induction, perturbation of tumor cell signaling, activation of complement dependent cytotoxicity (CDC), antibody dependent cellular cytotoxicity (ADCC), antibody dependent cellular phagocytosis (ADCP) and induction of adaptive immunity. Obinutuzumab (GA101) is a novel humanized, glycoengineered Type II anti-CD20 monoclonal antibody engineered for displaying enhanced FcγRIIIa (CD16) binding affinity and characterized by stronger induction of ADCC and direct tumor cell death when compared to wild-type, Type I anti-CD20 antibodies rituximab and ofatumumab. In light of the important role of phagocytic lineage cells in the mechanism of action of therapeutic antibodies, we compared GA101, rituximab and ofatumumab for their ability to trigger FcγR-dependent monocyte and macrophage effector functions. We show that, due to glycoengineering, GA101 displays superior CD16-dependent binding to monocytes, M1 and M2c macrophages in presence of nonspecific, competing, human endogenous IgGs, a situation that more closely mimics physiological conditions. Subsequently, GA101 more strongly engages monocytes and macrophages and leads to significantly higher elimination of CD20-expressing tumor cells as shown by assays detecting total antibody activity (ADCP, ADCC and direct effects). In support of the stronger GA101 activity, higher nitric-oxide (NO) levels are also detected in supernatants of tumor/macrophage co-cultures treated with antibody. Taken together, our data show that in addition to stronger NK-cell mediated ADCC and direct cell death induction due to Type II CD20 binding, GA101 more potently engages phagocytic-lineage cells resulting in enhanced monocyte and macrophage activity under conditions that more closely resemble physiological settings. Disclosures: Herter: Roche: Employment. Klein:Roche Glycart AG: Employment. Umana:Roche: Employment, Equity Ownership. Bacac:Roche: Employment.

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

Journal of Clinical Oncology ◽

10.1200/jco.2018.36.4_suppl.709 ◽

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.

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