Yuliya V. Katlinskaya

DNA-Damage-Induced Type I Interferon Promotes Senescence and Inhibits Stem Cell Function

Expression of type I interferons (IFNs) can be induced by DNA-damaging agents, but the mechanisms and significance of this regulation are not completely understood. We found that the transcription factor IRF3, activated in an ATM-IKKα/β-dependent manner, stimulates cell-autonomous IFN-β expression in response to double-stranded DNA breaks. Cells and tissues with accumulating DNA damage produce endogenous IFN-β and stimulate IFN signaling in vitro and in vivo. In turn, IFN acts to amplify DNA-damage responses, activate the p53 pathway, promote senescence, and inhibit stem cell function in response to telomere shortening. Inactivation of the IFN pathway abrogates the development of diverse progeric phenotypes and extends the lifespan of Terc knockout mice. These data identify DNA-damage-response-induced IFN signaling as a critical mechanism that links accumulating DNA damage with senescence and premature aging.

Type I Interferon Controls Propagation of Long Interspersed Element-1

Background: Type 1 interferons (IFN1) mediate defense against viruses but their role in regulating retrotransposon activities is unknown. Results: LINE-1 retrotransposon induces IFN1, which in turn inhibits LINE-1 retrotransposition. Conclusion: IFN1 regulate activities and propagation of LINE-1. Significance: Given that retrotransposons alter the genome, IFN1 play a role in maintenance of genomic integrity. Type I interferons (IFN) including IFNα and IFNβ are critical for the cellular defense against viruses. Here we report that increased levels of IFNβ were found in testes from mice deficient in MOV10L1, a germ cell-specific RNA helicase that plays a key role in limiting the propagation of retrotransposons including Long Interspersed Element-1 (LINE-1). Additional experiments revealed that activation of LINE-1 retrotransposons increases the expression of IFNβ and of IFN-stimulated genes. Conversely, pretreatment of cells with IFN suppressed the replication of LINE-1. Furthermore, the efficacy of LINE-1 replication was increased in isogenic cell lines harboring inactivating mutations in diverse elements of the IFN signaling pathway. Knockdown of the IFN receptor chain IFNAR1 also stimulated LINE-1 propagation in vitro. Finally, a greater accumulation of LINE-1 was found in mice that lack IFNAR1 compared with wild type mice. We propose that LINE-1-induced IFN plays an important role in restricting LINE-1 propagation and discuss the putative role of IFN in preserving the genome stability.

Suppression of Type I Interferon Signaling Overcomes Oncogene-Induced Senescence and Mediates Melanoma Development and Progression

Oncogene activation induces DNA damage responses and cell senescence. We report a key role of type I interferons (IFNs) in oncogene-induced senescence. IFN signaling-deficient melanocytes expressing activated Braf do not exhibit senescence and develop aggressive melanomas. Restoration of IFN signaling in IFN-deficient melanoma cells induces senescence and suppresses melanoma progression. Additional data from human melanoma patients and mouse transplanted tumor models suggest the importance of non-cell-autonomous IFN signaling. Inactivation of the IFN pathway is mediated by the IFN receptor IFNAR1 downregulation that invariably occurs during melanoma development. Mice harboring an IFNAR1 mutant, which is partially resistant to downregulation, delay melanoma development, suppress metastatic disease, and better respond to BRAF or PD-1 inhibitors. These results suggest that IFN signaling is an important tumor-suppressive pathway that inhibits melanoma development and progression and argue for targeting IFNAR1 downregulation to prevent metastatic disease and improve the efficacy of molecularly target and immune-targeted melanoma therapies.

Type I Interferons Control Proliferation and Function of the Intestinal Epithelium

ABSTRACT Wnt pathway-driven proliferation and renewal of the intestinal epithelium must be tightly controlled to prevent development of cancer and barrier dysfunction. Although type I interferons (IFN) produced in the gut under the influence of microbiota are known for their antiproliferative effects, the role of these cytokines in regulating intestinal epithelial cell renewal is largely unknown. Here we report a novel role for IFN in the context of intestinal knockout of casein kinase 1α (CK1α), which controls the ubiquitination and degradation of both β-catenin and the IFNAR1 chain of the IFN receptor. Ablation of CK1α leads to the activation of both β-catenin and IFN pathways and prevents the unlimited proliferation of intestinal epithelial cells despite constitutive β-catenin activity. IFN signaling contributes to the activation of the p53 pathway and the appearance of apoptotic and senescence markers in the CK1α-deficient gut. Concurrent genetic ablation of CK1α and IFNAR1 leads to intestinal hyperplasia, robust attenuation of apoptosis, and rapid and lethal loss of barrier function. These data indicate that IFN play an important role in controlling the proliferation and function of the intestinal epithelium in the context of β-catenin activation.

PERK Is a Haploinsufficient Tumor Suppressor: Gene Dose Determines Tumor-Suppressive Versus Tumor Promoting Properties of PERK in Melanoma.

The unfolded protein response (UPR) regulates cell fate following exposure of cells to endoplasmic reticulum stresses. PERK, a UPR protein kinase, regulates protein synthesis and while linked with cell survival, exhibits activities associated with both tumor progression and tumor suppression. For example, while cells lacking PERK are sensitive to UPR-dependent cell death, acute activation of PERK triggers both apoptosis and cell cycle arrest, which would be expected to contribute tumor suppressive activity. We have evaluated these activities in the BRAF-dependent melanoma and provide evidence revealing a complex role for PERK in melanoma where a 50% reduction is permissive for BrafV600E-dependent transformation, while complete inhibition is tumor suppressive. Consistently, PERK mutants identified in human melanoma are hypomorphic with dominant inhibitory function. Strikingly, we demonstrate that small molecule PERK inhibitors exhibit single agent efficacy against BrafV600E-dependent tumors highlighting the clinical value of targeting PERK.

Type 1 interferons contribute to the clearance of senescent cell

The major known function of cytokines that belong to type I interferons (IFN, including IFNα and IFNβ) is to mount the defense against viruses. This function also protects the genetic information of host cells from alterations in the genome elicited by some of these viruses. Furthermore, recent studies demonstrated that IFN also restrict proliferation of damaged cells by inducing cell senescence. Here we investigated the subsequent role of IFN in elimination of the senescent cells. Our studies demonstrate that endogenous IFN produced by already senescent cells contribute to increased expression of the natural killer (NK) receptor ligands, including MIC-A and ULBP2. Furthermore, neutralization of endogenous IFN or genetic ablation of its receptor chain IFNAR1 compromises the recognition of senescent cells and their clearance in vitro and in vivo. We discuss the role of IFN in protecting the multi-cellular host from accumulation of damaged senescent cells and potential significance of this mechanism in human cancers.

A potent in vivo anti-tumor efficacy of novel recombinant type I interferon.

Purpose: Antiproliferative, antiviral, and immunomodulatory activities of endogenous type I IFNs (IFN1) prompt the design of recombinant IFN1 for therapeutic purposes. However, most of the designed IFNs exhibited suboptimal therapeutic efficacies against solid tumors. Here, we report evaluation of the in vitro and in vivo antitumorigenic activities of a novel recombinant IFN termed sIFN-I. Experimental Design: We compared primary and tertiary structures of sIFN-I with its parental human IFNα-2b, as well as affinities of these ligands for IFN1 receptor chains and pharmacokinetics. These IFN1 species were also compared for their ability to induce JAK–STAT signaling and expression of the IFN1-stimulated genes and to elicit antitumorigenic effects. Effects of sIFN-I on tumor angiogenesis and immune infiltration were also tested in transplanted and genetically engineered immunocompetent mouse models. Results: sIFN-I displayed greater affinity for IFNAR1 (over IFNAR2) chain of the IFN1 receptor and elicited a greater extent of IFN1 signaling and expression of IFN-inducible genes in human cells. Unlike IFNα-2b, sIFN-I induced JAK–STAT signaling in mouse cells and exhibited an extended half-life in mice. Treatment with sIFN-I inhibited intratumoral angiogenesis, increased CD8+ T-cell infiltration, and robustly suppressed growth of transplantable and genetically engineered tumors in immunodeficient and immunocompetent mice. Conclusions: These findings define sIFN-I as a novel recombinant IFN1 with potent preclinical antitumorigenic effects against solid tumor, thereby prompting the assessment of sIFN-I clinical efficacy in humans. Clin Cancer Res; 23(8); 2038–49. ©2016 AACR.

Abstract 1637: ICOS agonism induces potent immune activation and anti-tumor response in non-clinical models

Inducible T-cell costimulator (ICOS) is a costimulatory receptor that is upregulated on activated CD4 and CD8 T cells and plays an important role in T cell survival, differentiation, regulation of memory and regulatory T cell pools and humoral responses. Preclinically, augmenting signaling through the ICOS pathway has been reported to induce anti-tumor activity and enhance responses to CTLA4 blockade. Here we present non-clinical data evaluating ICOS agonist antibody activity in human and mouse model systems using a different antibody for each species. GSK3359609 is a novel, selective anti-human ICOS agonist. GSK3359609 induces ICOS signaling through phosphorylation of intermediates in the Pi3K pathway leading to lymphocyte activation, proliferation and pro-inflammatory cytokine secretion in human PBMC in-vitro. A robust increase in CD4 effector T cell proliferation and Granzyme B secreting CD8 T cells was observed with GSK3359609 treatment in in-vitro assays utilizing PBMC from healthy donors, cancer patients or tumor infiltrating lymphocytes (TIL). Modest induction of regulatory T cell proliferation and IL-10 secretion were also observed. Significant increase in IFNγ (p We further explored treatment settings where a combination therapy may condition the tumor immune microenvironment to a more favorable context for ICOS agonist therapy. Treatment with an anti-PD1 antibody resulted in strong upregulation of ICOS expression on tumor infiltrating CD8, CD4 effector and regulatory T cells while decreasing ICOS+ Tregs relative to CD8 and CD4 effectors in the tumor microenvironment. Synergistic anti-tumor activity was observed for the combination of PD-1 with ICOS agonist antibodies in preclinical studies. These studies provide a strong rationale for the ongoing FTIH Phase I study of GSK3359609 administered alone and in combination with pembrolizumab to patients with selected advanced solid tumors. Citation Format: Sapna Yadavilli, Tianqian Zhang, Ashleigh Hahn, Laura M. Seestaller-Wehr, Hong Shi, Yao-Bin Liu, M.Phillip DeYoung, David J. Kilian, Meixia Bi, Michael P. Adam, Shu-Yun Zhang, Sabyasachi Bhattacharya, Yuliya Katlinskaya, Christina Blackwell, Christopher B. Hopson, Niranjan Yanamandra, Roopa Srinivasan, Patrick A. Mayes, Axel Hoos. ICOS agonism induces potent immune activation and anti-tumor response in non-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1637. doi:10.1158/1538-7445.AM2017-1637

Abstract A63: IFNAR1 downregulation during melanoma progression upregulates αv expression and promotes metastasis

The anti-metastatic effects of type 1 interferon (IFN1) prompted its use for adjuvant therapy in malignant melanoma patients at high risk for developing metastasis. While IFN1 adjuvant therapy continues to be the preferred treatment, many patients fail to elicit response to IFN1 treatment and progress to develop distal metastases often resulting in a lethal outcome. We observed downregulation of the IFNAR1 chain of the IFN1 receptor and suppression of IFN1 signaling in genetically engineered mouse melanomas driven by melanocyte-specific activation of Braf and inactivation of Pten . Induction of melanoma in animals expressing IFNAR1 that is deficient in ubiquitination and degradation led to a delayed onset of the disease and decreased number of local metastases. Remarkably, no distant metastases were found in these mice despite substantial primary tumor burden. Gene set enrichment analysis demonstrated a dramatic loss of the αv integrin pathway signature in mice harboring stabilized IFNAR1. Conversely, melanomas induced in Ifnar1 knockout mice yielded transplantable cell lines that displayed high levels of αv expression. Restoring IFNAR1 expression in these cells led to the loss of αv expression. We discuss the role of these mechanisms in melanoma metastasis and refractoriness to IFN1-based therapy. Citation Format: Angelica Ortiz, Yuliya V. Katlinskaya, Kanstantsin V. Katlinski, Serge Y. Fuchs. IFNAR1 downregulation during melanoma progression upregulates αv expression and promotes metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr A63.