Gene Summary

Gene:IL15; interleukin 15
Aliases: IL-15
Summary:The protein encoded by this gene is a cytokine that regulates T and natural killer cell activation and proliferation. This cytokine and interleukine 2 share many biological activities. They are found to bind common hematopoietin receptor subunits, and may compete for the same receptor, and thus negatively regulate each other's activity. The number of CD8+ memory cells is shown to be controlled by a balance between this cytokine and IL2. This cytokine induces the activation of JAK kinases, as well as the phosphorylation and activation of transcription activators STAT3, STAT5, and STAT6. Studies of the mouse counterpart suggested that this cytokine may increase the expression of apoptosis inhibitor BCL2L1/BCL-x(L), possibly through the transcription activation activity of STAT6, and thus prevent apoptosis. Alternatively spliced transcript variants of this gene have been reported. [provided by RefSeq, Feb 2011]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 16 March, 2017


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 16 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 16 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: IL15 (cancer-related)

Hinrichs CS
Molecular Pathways: Breaking the Epithelial Cancer Barrier for Chimeric Antigen Receptor and T-cell Receptor Gene Therapy.
Clin Cancer Res. 2016; 22(7):1559-64 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Adoptive transfer of T cells genetically engineered to express a tumor-targeting chimeric antigen receptor (CAR) or T-cell receptor (TCR) can mediate cancer regression in some patients. CARs are synthetic single-chain proteins that use antibody domains to target cell surface antigens. TCRs are natural heterodimeric proteins that can target intracellular antigens through recognition of peptides bound to human leukocyte antigens. CARs have shown promise in B-cell malignancies and TCRs in melanoma, but neither approach has achieved clear success in an epithelial cancer. Treatment of epithelial cancers may be particularly challenging because of a paucity of target antigens expressed by carcinomas and not by important healthy tissues. In addition, epithelial cancers may be protected by inhibitory ligands and soluble factors in the tumor microenvironment. One strategy to overcome these negative regulators is to modulate expression of T-cell genes to enhance intrinsic T-cell function. Programmable nucleases, which can suppress inhibitory genes, and inducible gene expression systems, which can enhance stimulatory genes, are entering clinical testing. Other work is delineating whether control of genes for immune checkpoint receptors (e.g.,PDCD1, CTLA4) and cytokine and TCR signaling regulators (e.g.,CBLB, CISH, IL12, IL15) can increase the antitumor activity of therapeutic T cells.

Jaime-Ramirez AC, McMichael EL, Kondadasula S, et al.
NK Cell-Mediated Antitumor Effects of a Folate-Conjugated Immunoglobulin Are Enhanced by Cytokines.
Cancer Immunol Res. 2016; 4(4):323-36 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Optimally effective antitumor therapies would not only activate immune effector cells but also engage them at the tumor. Folate conjugated to immunoglobulin (F-IgG) could direct innate immune cells with Fc receptors to folate receptor-expressing cancer cells. F-IgG bound to human KB and HeLa cells, as well as murine L1210JF, a folate receptor (FR)-overexpressing cancer cell line, as determined by flow cytometry. Recognition of F-IgG by natural killer (NK) cell Fc receptors led to phosphorylation of the ERK transcription factor and increased NK cell expression of CD69. Lysis of KB tumor cells by NK cells increased by about 5-fold after treatment with F-IgG, an effect synergistically enhanced by treatment with IL2, IL12, IL15, or IL21 (P< 0.001). F-IgG also enhanced the lysis of chronic lymphocytic leukemia cells by autologous NK cells. NK cells significantly increased production of IFNγ, MIP-1α, and RANTES in response to F-IgG-coated KB target cells in the presence of the NK cell-activating cytokine IL12, and these coculture supernatants induced significant T-cell chemotaxis (P< 0.001). F-IgG-coated targets also stimulated FcR-mediated monocyte effector functions. Studies in a murine leukemia model confirmed the intratumoral localization and antitumor activity of F-IgG, as well as enhancement of its effects by IL12 (P =0.05). The antitumor effect of this combination was dependent on NK cells and led to decreased tumor cell proliferation in vivo Thus, F-IgG can induce an immune response against FR-positive tumor cells that is mediated by NK cells and can be augmented by cytokine therapy.

Mehta RS, Chen X, Antony J, et al.
Generating Peripheral Blood Derived Lymphocytes Reacting Against Autologous Primary AML Blasts.
J Immunother. 2016 Feb-Mar; 39(2):71-80 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Expanding on our prior studies with cord blood T cells, we hypothesized that primary acute myeloid leukemia (AML)-reactive autologous T cells could be generated ex vivo under immunomodulatory conditions. We purified AML and T cells from 8 newly diagnosed high-risk patients. After 2 weeks expansion, T cells were stimulated with interferon-γ-treated autologous AML weekly × 3, interleukin-15, and agonistic anti-CD28 antibody. Cytotoxic T cells and ELISpot assays tested functionality; reverse transcriptase quantitative polymerase chain reaction tested AML and T-cell gene expression profiles. On the basis of combined positive ELIspot and cytotoxic T cells assays, T cells reactive against AML were generated in 5 of 8 patients. Treg proportion declined after cocultures in reactive T-cell samples. AML-reactive T cells displayed an activated gene expression profile. "Resistant" AML blasts displayed genes associated with immunosuppressive myeloid-derived suppressor cells. We discuss our approach to creating primary AML-reactive autologous T cell and limitations that require further work. Our study provides a platform for future research targeting on generating autologous leukemia-reactive T cells.

Hu Z, Xia J, Fan W, et al.
Human melanoma immunotherapy using tumor antigen-specific T cells generated in humanized mice.
Oncotarget. 2016; 7(6):6448-59 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
A major factor hindering the exploration of adoptive immunotherapy in preclinical settings is the limited availability of tumor-reactive human T cells. Here we developed a humanized mouse model that permits large-scale production of human T cells expressing the engineered melanoma antigen MART-1-specific TCR. Humanized mice, made by transplantation of human fetal thymic tissue and CD34+ cells virally-transduced with HLA class I-restricted melanoma antigen (MART-1)-specific TCR gene, showed efficient development of MART-1-TCR+ human T cells with predominantly CD8+ cells. Importantly, MART-1-TCR+CD8+ T cells developing in these mice were capable of mounting antigen-specific responses in vivo, as evidenced by their proliferation, phenotypic conversion and IFN-γ production following MART-1 peptide immunization. Moreover, these MART-1-TCR+CD8+ T cells mediated efficient killing of melanoma cells in an HLA/antigen-dependent manner. Adoptive transfer of in vitro expanded MART-1-TCR+CD8+ T cells induced potent antitumor responses that were further enhanced by IL-15 treatment in melanoma-bearing recipients. Finally, a short incubation of MART-1-specific T cells with rapamycin acted synergistically with IL-15, leading to significantly improved tumor-free survival in recipients with metastatic melanoma. These data demonstrate the practicality of using humanized mice to produce potentially unlimited source of tumor-specific human T cells for experimental and preclinical exploration of cancer immunotherapy. This study also suggests that pretreatment of tumor-reactive T cells with rapamycin in combination with IL-15 administration may be a novel strategy to improve the efficacy of adoptive T cell therapy.

Sun H, Liu D
IL-15/sIL-15Rα gene transfer suppresses Lewis lung cancer growth in the lungs, liver and kidneys.
Cancer Gene Ther. 2016 Feb-Mar; 23(2-3):54-60 [PubMed] Related Publications
Nearly 40% of people with lung cancer have tumor growth in other organs at the time of diagnosis. Current treatment strategies for patients with late-stage lung cancer are primarily palliative and only showed modest efficacy. The current study takes advantage of the hydrodynamic gene delivery technique to evaluate the antitumor activity of interleukin (IL)-15/sIL-15Rα on lung tumors growing in the lungs, liver and kidneys. We demonstrate that hydrodynamic tail vein injection of 2 μg of AG209 DP muIL-15sRα+IL-15 plasmid resulted in serum IL-15/sIL-15Rα reaching a peak level of ~10 μg ml(-1) 1 day after the injection and gradually declined to ~5 ng ml(-1) within 3 days. Quantitative PCR analysis revealed that overexpression of IL-15/sIL-15Rα induced the activation of natural killer and T cells, evidenced by increased mRNA levels of marker genes including granzyme B, perforin, Ifn-γ, T-bet and Cd8 in the lungs, liver and kidneys. Importantly, transfer of the Il-15/sIl-15Rα gene alone, or in combination with gemcitabine chemotherapy, significantly inhibited the tumor growth in these three organs and prolonged median survival time of treated mice by 1.7- and 3.3-fold, respectively. The therapeutic benefits are principally blockade and elimination of tumor growth in the liver and kidneys. Taken together, these results suggest that IL-15/sIL-15Rα-based gene therapy could be an effective approach to treat late-stage lung cancer with metastases in other organs.

Pilipow K, Roberto A, Roederer M, et al.
IL15 and T-cell Stemness in T-cell-Based Cancer Immunotherapy.
Cancer Res. 2015; 75(24):5187-93 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Preclinical models revealed that the immune system can mediate rejection of established tumors, but direct evidence in humans has been limited to largely immunogenic tumors, such as melanoma. The recent success of immune checkpoint inhibitors and adoptive T-cell transfer immunotherapy in clinical trials has instilled new hope for the use of T-cell immunotherapy in the treatment of cancer. IL15, a potent immunostimulatory cytokine, both potentiates host T-cells and natural killer (NK) cell immune responses and promotes the generation of long-lived memory T cells with superior functional capacity, with potential use in adoptive T-cell transfer protocols. IL15 has been recently tested in the clinic and showed dramatic effects at the level of responding NK and CD8(+) memory T cells. The recent advances in the knowledge of IL15-dependent regulation of T-cell responses, gene expression, and metabolic adaptation have important implications for the use of IL15 in T-cell-based immunotherapy of cancer.

Rhode PR, Egan JO, Xu W, et al.
Comparison of the Superagonist Complex, ALT-803, to IL15 as Cancer Immunotherapeutics in Animal Models.
Cancer Immunol Res. 2016; 4(1):49-60 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
IL15, a potent stimulant of CD8(+) T cells and natural killer (NK) cells, is a promising cancer immunotherapeutic. ALT-803 is a complex of an IL15 superagonist mutant and a dimeric IL15 receptor αSu/Fc fusion protein that was found to exhibit enhanced biologic activity in vivo, with a substantially longer serum half-life than recombinant IL15. A single intravenous dose of ALT-803, but not IL15, eliminated well-established tumors and prolonged survival of mice bearing multiple myeloma. In this study, we extended these findings to demonstrate the superior antitumor activity of ALT-803 over IL15 in mice bearing subcutaneous B16F10 melanoma tumors and CT26 colon carcinoma metastases. Tissue biodistribution studies in mice also showed much greater retention of ALT-803 in the lymphoid organs compared with IL15, consistent with its highly potent immunostimulatory and antitumor activities in vivo. Weekly dosing with 1 mg/kg ALT-803 in C57BL/6 mice was well tolerated, yet capable of increasing peripheral blood lymphocyte, neutrophil, and monocyte counts by >8-fold. ALT-803 dose-dependent stimulation of immune cell infiltration into the lymphoid organs was also observed. Similarly, cynomolgus monkeys treated weekly with ALT-803 showed dose-dependent increases of peripheral blood lymphocyte counts, including NK, CD4(+), and CD8(+) memory T-cell subsets. In vitro studies demonstrated ALT-803-mediated stimulation of mouse and human immune cell proliferation and IFNγ production without inducing a broad-based release of other proinflammatory cytokines (i.e., cytokine storm). Based on these results, a weekly dosing regimen of ALT-803 has been implemented in multiple clinical studies to evaluate the dose required for effective immune cell stimulation in humans.

Adachi T, Kobayashi T, Sugihara E, et al.
Hair follicle-derived IL-7 and IL-15 mediate skin-resident memory T cell homeostasis and lymphoma.
Nat Med. 2015; 21(11):1272-9 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
The skin harbors a variety of resident leukocyte subsets that must be tightly regulated to maintain immune homeostasis. Hair follicles are unique structures in the skin that contribute to skin dendritic cell homeostasis through chemokine production. We demonstrate that CD4(+) and CD8(+) skin-resident memory T cells (TRM cells), which are responsible for long-term skin immunity, reside predominantly within the hair follicle epithelium of the unperturbed epidermis. TRM cell tropism for the epidermis and follicles is herein termed epidermotropism. Hair follicle expression of IL-15 was required for CD8(+) TRM cells, and IL-7 for CD8(+) and CD4(+) TRM cells, to exert epidermotropism. A lack of either cytokine in the skin led to impaired hapten-induced contact hypersensitivity responses. In a model of cutaneous T cell lymphoma, epidermotropic CD4(+) TRM lymphoma cell localization depended on the presence of hair follicle-derived IL-7. These findings implicate hair follicle-derived cytokines as regulators of malignant and non-malignant TRM cell tissue residence, and they suggest that the cytokines may be targeted therapeutically in inflammatory skin diseases and lymphoma.

Rosario M, Liu B, Kong L, et al.
The IL-15-Based ALT-803 Complex Enhances FcγRIIIa-Triggered NK Cell Responses and In Vivo Clearance of B Cell Lymphomas.
Clin Cancer Res. 2016; 22(3):596-608 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
PURPOSE: Anti-CD20 monoclonal antibodies (mAb) are an important immunotherapy for B-cell lymphoma, and provide evidence that the immune system may be harnessed as an effective lymphoma treatment approach. ALT-803 is a superagonist IL-15 mutant and IL-15Rα-Fc fusion complex that activates the IL-15 receptor constitutively expressed on natural killer (NK) cells. We hypothesized that ALT-803 would enhance anti-CD20 mAb-directed NK-cell responses and antibody-dependent cellular cytotoxicity (ADCC).
EXPERIMENTAL DESIGN: We tested this hypothesis by adding ALT-803 immunostimulation to anti-CD20 mAb triggering of NK cells in vitro and in vivo. Cell lines and primary human lymphoma cells were utilized as targets for primary human NK cells. Two complementary in vivo mouse models were used, which included human NK-cell xenografts in NOD/SCID-γc (-/-) mice.
RESULTS: We demonstrate that short-term ALT-803 stimulation significantly increased degranulation, IFNγ production, and ADCC by human NK cells against B-cell lymphoma cell lines or primary follicular lymphoma cells. ALT-803 augmented cytotoxicity and the expression of granzyme B and perforin, providing one potential mechanism for this enhanced functionality. Moreover, in two distinct in vivo B-cell lymphoma models, the addition of ALT-803 to anti-CD20 mAb therapy resulted in significantly reduced tumor cell burden and increased survival. Long-term ALT-803 stimulation of human NK cells induced proliferation and NK-cell subset changes with preserved ADCC.
CONCLUSIONS: ALT-803 represents a novel immunostimulatory drug that enhances NK-cell antilymphoma responses in vitro and in vivo, thereby supporting the clinical investigation of ALT-803 plus anti-CD20 mAbs in patients with indolent B-cell lymphoma.

Zhang M, Mathews Griner LA, Ju W, et al.
Selective targeting of JAK/STAT signaling is potentiated by Bcl-xL blockade in IL-2-dependent adult T-cell leukemia.
Proc Natl Acad Sci U S A. 2015; 112(40):12480-5 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Adult T-cell leukemia (ATL) develops in individuals infected with human T-cell lymphotropic virus-1 (HTLV-1). Presently there is no curative therapy for ATL. HTLV-1-encoded protein Tax (transactivator from the X-gene region) up-regulates Bcl-xL (B-cell lymphoma-extra large) expression and activates interleukin-2 (IL-2), IL-9, and IL-15 autocrine/paracrine systems, resulting in amplified JAK/STAT signaling. Inhibition of JAK signaling reduces cytokine-dependent ex vivo proliferation of peripheral blood mononuclear cells (PBMCs) from ATL patients in smoldering/chronic stages. Currently, two JAK inhibitors are approved for human use. In this study, we examined activity of multiple JAK inhibitors in ATL cell lines. The selective JAK inhibitor ruxolitinib was examined in a high-throughput matrix screen combined with >450 potential therapeutic agents, and Bcl-2/Bcl-xL inhibitor navitoclax was identified as a strong candidate for multicomponent therapy. The combination was noted to strongly activate BAX (Bcl-2-associated X protein), effect mitochondrial depolarization, and increase caspase 3/7 activities that lead to cleavage of PARP (poly ADP ribose polymerase) and Mcl-1 (myeloid cell leukemia 1). Ruxolitinib and navitoclax independently demonstrated modest antitumor efficacy, whereas the combination dramatically lowered tumor burden and prolonged survival in an ATL murine model. This combination strongly blocked ex vivo proliferation of five ATL patients' PBMCs. These studies provide support for a therapeutic trial in patients with smoldering/chronic ATL using a drug combination that inhibits JAK signaling and antiapoptotic protein Bcl-xL.

Hira SK, Mondal I, Bhattacharya D, et al.
Downregulation of STAT3 phosphorylation enhances tumoricidal effect of IL-15-activated dendritic cell against doxorubicin-resistant lymphoma and leukemia via TNF-α.
Int J Biochem Cell Biol. 2015; 67:1-13 [PubMed] Related Publications
Although disputed by some, increasing evidence suggests that TNF-α synergies with traditional chemotherapeutic drugs to exert a heightened antitumor effect. The present study investigated the antitumor efficacy of recombinant IL-15 in combination with the STAT3 inhibitor cucurbitacin-I in a doxorubicin-resistant murine lymphoma model. The significance of the work is to understand and design effective strategies in doxorubicin resistant lymphomas. TNF-α is downregulated in dendritic cells from mice with Dalton's lymphoma and shows an inverse relationship with disease progression. Doxorubicin-resistant DL cells have elevated levels of Bcl-2 and Mcl-1 and increased phosphorylation of STAT3. These cells are refractory to dendritic cell derived TNF-α. Doxorubicin resistant Dalton's lymphoma is susceptible to dendritic cell derived TNF-α upon stimulation with the STAT3 inhibitor cucurbitacin-I, which downregulates STAT3 and other survival molecules. The combined treatment of low dose of cucurbitacin-I and rIL-15 is ineffective in mice with doxorubicin resistant Dalton's lymphoma, but a similar therapy prolongs the survival of mice transplanted with parental Dalton's lymphoma. Doxorubicin resistant Dalton's lymphoma responds to therapy with high doses of cucurbitacin-I and rIL-15. Dendritic cell derived from mice responded positively to the therapy and regained their tumoricidal properties with respect to growth inhibition and killing of DL tumor cells. Similar to DL, DC derived from CML patients are impaired in TNF-α expression and are unable to restrict the growth of drug-resistant lymphoma and leukemia cells. This combination approach could be used as a new therapeutic strategy for aggressive and highly metastatic doxorubicin resistant lymphoma.

Khaznadar Z, Boissel N, Agaugué S, et al.
Defective NK Cells in Acute Myeloid Leukemia Patients at Diagnosis Are Associated with Blast Transcriptional Signatures of Immune Evasion.
J Immunol. 2015; 195(6):2580-90 [PubMed] Related Publications
Acute myeloid leukemia (AML) is a heterogeneous group of malignancies that may be sensitive to the NK cell antitumor response. However, NK cells are frequently defective in AML. In this study, we found in an exploratory cohort (n = 46) that NK cell status at diagnosis of AML separated patients in two groups with a different clinical outcome. Patients with a deficient NK cell profile, including reduced expression of some activating NK receptors (e.g., DNAX accessory molecule-1, NKp46, and NKG2D) and decreased IFN-γ production, had a significantly higher risk of relapse (p = 0.03) independently of cytogenetic classification in multivariate analysis. Patients with defective NK cells showed a profound gene expression decrease in AML blasts for cytokine and chemokine signaling (e.g., IL15, IFNGR1, IFNGR2, and CXCR4), Ag processing (e.g., HLA-DRA, HLA-DRB1, and CD74) and adhesion molecule pathways (e.g., PVR and ICAM1). A set of 388 leukemic classifier genes defined in the exploratory cohort was independently validated in a multicentric cohort of 194 AML patients. In total, these data evidenced the interplay between NK cells and AML blasts at diagnosis allowing an immune-based stratification of AML patients independently of clinical classifications.

Ramanayake S, Bilmon I, Bishop D, et al.
Low-cost generation of Good Manufacturing Practice-grade CD19-specific chimeric antigen receptor-expressing T cells using piggyBac gene transfer and patient-derived materials.
Cytotherapy. 2015; 17(9):1251-67 [PubMed] Related Publications
BACKGROUND AIMS: Protocols for the production of CD19-specific chimeric antigen receptor (CAR19) T cells are often complex and expensive because of the use of retroviral and lentiviral vectors or the need for CAR19 T-cell enrichment. We aimed to simplify the generation of CAR19 T cells from the peripheral blood of normal donors and patients using the piggyBac transposon system of gene modification.
METHODS: We varied electroporation voltage, cytokines and stimulation conditions for the generation and expansion of CAR19 T cells over a 3-week culture period.
RESULTS: Using optimized electroporation voltage, interleukin-15 alone and co-culturing CAR T cells with peripheral blood mononuclear cells, we were able to expand CAR19 T-cell cultures by up to 765-fold over 3 weeks in normal donors and 180-fold in patients with B-cell malignancies. Final median CAR19 expression of 72% was seen in normal donors, and 81% was seen in patients with acute lymphoblastic leukaemia, chronic lymphocytic leukemia or non-Hodgkin lymphoma. CAR19 T cells produced interferon gamma on stimulation with CD19(+) cell lines and efficiently lysed both CD19(+) cell lines and primary leukemia cells. In addition, combining CAR expression with an inducible caspase safety switch allowed elimination of CAR19 T cells by the application of a small molecule dimerizer.
DISCUSSION: We have produced a simple, inexpensive and easily adoptable protocol for the generation of CAR19 T cells suitable for use in clinical trials using the piggyBac transposon system. This provides a robust platform for further enhancing the T-cell product and testing new CAR technologies.

Azzi S, Gallerne C, Romei C, et al.
Human Renal Normal, Tumoral, and Cancer Stem Cells Express Membrane-Bound Interleukin-15 Isoforms Displaying Different Functions.
Neoplasia. 2015; 17(6):509-17 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Intrarenal interleukin-15 (IL-15) participates to renal pathophysiology, but the role of its different membrane-bound isoforms remains to be elucidated. In this study, we reassess the biology of membrane-bound IL-15 (mb-IL-15) isoforms by comparing primary cultures of human renal proximal tubular epithelial cells (RPTEC) to peritumoral (ptumTEC), tumoral (RCC), and cancer stem cells (CSC/CD105(+)). RPTEC express a 14 to 16 kDa mb-IL-15, whose existence has been assumed but never formally demonstrated and likely represents the isoform anchored at the cell membrane through the IL-15 receptor α (IL-15Rα) chain, because it is sensitive to acidic treatment and is not competent to deliver a reverse signal. By contrast, ptumTEC, RCC, and CSC express a novel N-hyperglycosylated, short-lived transmembrane mb-IL-15 (tmb-IL-15) isoform around 27 kDa, resistant to acidic shock, delivering a reverse signal in response to its soluble receptor (sIL-15Rα). This reverse signal triggers the down-regulation of the tumor suppressor gene E-cadherin in ptumTEC and RCC but not in CSC/CD105(+), where it promotes survival. Indeed, through the AKT pathway, tmb-IL-15 protects CSC/CD105(+) from non-programmed cell death induced by serum starvation. Finally, both mb-IL-15 and tmb-IL-15 are sensitive to metalloproteases, and the cleaved tmb-IL-15 (25 kDa) displays a powerful anti-apoptotic effect on human hematopoietic cells. Overall, our data indicate that both mb-IL-15 and tmb-IL-15 isoforms play a complex role in renal pathophysiology downregulating E-cadherin and favoring cell survival. Moreover, "apparently normal" ptumTEC cells, sharing different properties with RCC, could contribute to organize an enlarged peritumoral "preneoplastic" environment committed to favor tumor progression.

Heon EK, Wulan H, Macdonald LP, et al.
IL-15 induces strong but short-lived tumor-infiltrating CD8 T cell responses through the regulation of Tim-3 in breast cancer.
Biochem Biophys Res Commun. 2015; 464(1):360-6 [PubMed] Related Publications
IL-15 has pivotal roles in the control of CD8(+) memory T cells and has been investigated as a therapeutic option in cancer therapy. Although IL-15 and IL-2 share many functions together, including the stimulation of CD8 T cell proliferation and IFN-γ production, the different in vivo roles of IL-15 and IL-2 have been increasingly recognized. Here, we explored the different effects of IL-15 and IL-2 on tumor-infiltrating (TI) T cells from resected breast tumors. We found that neither IL-2 nor IL-15 induced intratumoral CD8 T cell proliferation by itself, but after CD3/CD28-stimulation, IL-15 induced significantly higher proliferation than IL-2 during early time points, at day 2, day 3 and day 6. However, the IL-15-induced proliferation leveled off at day 9 and day 12, whereas IL-2 induced lower but progressive proliferation at each time point. Furthermore, IL-15 caused an early and robust increase of IFN-γ in the supernatant of TI cell cultures, which diminished at later time points, while the IL-2-induced IFN-γ production remained constant over time. In addition, the IL-15-costimulated CD8 T cells presented higher frequencies of apoptotic cells. The diminishing IL-15-induced response was possibly due to regulatory and/or exhaustion mechanisms. We did not observe increased IL-10 or PD-1 upregulation, but we have found an increase of Tim-3 upregulation on IL-15-, but not IL-2-stimulated cells. Blocking Tim-3 function using anti-Tim-3 antibodies resulted in increased IL-15-induced proliferation and IFN-γ production for a prolonged period of time, whereas adding Tim-3 ligand galectin 9 led to reduced proliferation and IFN-γ production. Our results suggest that IL-15 in combination of Tim-3 blocking antibodies could potentially act as an IL-2 alternative in tumor CD8 T cell expansion in vitro, a crucial step in adoptive T cell therapy.

Shi L, Liu T, Zhang M, et al.
miR-15b is Downregulated in Myasthenia Gravis Patients and Directly Regulates the Expression of Interleukin-15 (IL-15) in Experimental Myasthenia Gravis Mice.
Med Sci Monit. 2015; 21:1774-80 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
BACKGROUND: miR-15b is significantly and consistently downregulated in different clinical phenotypes of myasthenia gravis (MG). However, its role in pathogenesis of MG is still not clear. This study aimed to explore the function of miR-15b in MG.
MATERIAL AND METHODS: Blood samples from early-onset MG, late-onset MG, thymoma patients, and healthy participants were collected. The expression pattern of IL-15 and miR-15b was identified by qRT-PCR and ELISA in patient serum and mouse tissue samples. The regulative role of miR-15b on IL-15 expression was verified in an experimental autoimmune myasthenia gravis (EAMG) mice model.
RESULTS: qRT-PCR and ELISA showed that miR-15b expression was significantly lower and IL-15 expression was significantly higher in all EMG, LMG, and thymoma cases compared to healthy controls. Based on mouse model, we confirmed that miR-15b knockdown could increase IL-15 expression in healthy mice, while miR-15b overexpression could inhibit IL-15 expression in EAMG mice. Through searching in bioinformatics databases, we identified a highly conserved consequential pairing between IL-15 and miR-15b. Subsequent dual luciferase assay further verified this match.
CONCLUSIONS: This study is the first to report the miR-15b-IL-15 axis can directly regulate IL15 expression, which helps to further explain the abnormal IL-15 expression in MG patients and the pathogenesis of MG.

Yan C, Jie L, Yongqi W, et al.
Delivery of human NKG2D-IL-15 fusion gene by chitosan nanoparticles to enhance antitumor immunity.
Biochem Biophys Res Commun. 2015; 463(3):336-43 [PubMed] Related Publications
Nanoparticles are becoming promising carriers for gene delivery because of their high capacity in gene loading and low cell cytotoxicity. In this study, a chitosan-based nanoparticle encapsulated within a recombinant pcDNA3.1-dsNKG2D-IL-15 plasmid was generated. The fused dsNKG2D-IL-15 gene fragment consisted of double extracellular domains of NKG2D with IL-15 gene at downstream. The average diameter of the gene nanoparticles ranged from 200 nm to 400 nm, with mean zeta potential value of 53.8 ± 6.56 mV. The nanoparticles which were loaded with the dsNKG2D-IL-15 gene were uptaken by tumor cells with low cytotoxicity. Tumor cells pre-transfected by gene nanopartilces stimulated NK and T cells in vitro. Intramuscular injection of gene nanoparticles suppressed tumor growth and prolonged survival of tumor-bearing mice through activation of NK and CD8(+) T cells. Thus, chitosan-based nanoparticle delivery of dsNKG2D-IL-15 gene vaccine can be potentially used for tumor therapy.

Croci S, Nanni P, Palladini A, et al.
Interleukin-15 is required for immunosurveillance and immunoprevention of HER2/neu-driven mammary carcinogenesis.
Breast Cancer Res. 2015; 17:70 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
INTRODUCTION: We previously demonstrated that HER2/neu-driven mammary carcinogenesis can be prevented by an interleukin-12 (IL-12)-adjuvanted allogeneic HER2/neu-expressing cell vaccine. Since IL-12 can induce the release of interleukin-15 (IL-15), in the present study we investigated the role played by IL-15 in HER2/neu driven mammary carcinogenesis and in its immunoprevention.
METHODS: HER2/neu transgenic mice with homozygous knockout of IL-15 (here referred to as IL15KO/NeuT mice) were compared to IL-15 wild-type HER2/neu transgenic mice (NeuT) regarding mammary carcinogenesis, profile of peripheral blood lymphocytes and splenocytes and humoral and cellular responses induced by the vaccine.
RESULTS: IL15KO/NeuT mice showed a significantly earlier mammary cancer onset than NeuT mice, with median latency times of 16 and 20 weeks respectively, suggesting a role for IL-15 in cancer immunosurveillance. Natural killer (NK) and CD8+ lymphocytes were significantly lower in IL15KO/NeuT mice compared to mice with wild-type IL-15. The IL-12-adjuvanted allogeneic HER2/neu-expressing cell vaccine was still able to delay mammary cancer onset but efficacy in IL-15-lacking mice vanished earlier: all vaccinated IL15KO/NeuT mice developed tumors within 80 weeks of age (median latency of 53 weeks), whereas more than 70 % of vaccinated NeuT mice remained tumor-free up to 80 weeks of age. Vaccinated IL15KO/NeuT mice showed less necrotic tumors with fewer CD3+ lymphocyes and lacked perforin-positive infiltrating cells compared to NeuT mice. Concerning the anti-vaccine antibody response, antibody titer was unaffected by the lack of IL-15, but less antibodies of IgM and IgG1 isotypes were found in IL15KO/NeuT mice. A lower induction by vaccine of systemic interferon-gamma (IFN-γ) and interleukin-5 (IL-5) was also observed in IL15KO/NeuT mice when compared to NeuT mice. Finally, we found a lower level of CD8+ memory cells in the peripheral blood of vaccinated IL15KO/NeuT mice compared to NeuT mice.
CONCLUSIONS: We demonstrated that IL-15 has a role in mammary cancer immunosurveillance and that IL-15-regulated NK and CD8+ memory cells play a role in long-lasting immunoprevention, further supporting the potential use of IL-15 as adjuvant in immunological strategies against tumors.

Mitra S, Ring AM, Amarnath S, et al.
Interleukin-2 activity can be fine tuned with engineered receptor signaling clamps.
Immunity. 2015; 42(5):826-38 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Interleukin-2 (IL-2) regulates lymphocyte function by signaling through heterodimerization of the IL-2Rβ and γc receptor subunits. IL-2 is of considerable therapeutic interest, but harnessing its actions in a controllable manner remains a challenge. Previously, we have engineered an IL-2 "superkine" with enhanced affinity for IL-2Rβ. Here, we describe next-generation IL-2 variants that function as "receptor signaling clamps." They retained high affinity for IL-2Rβ, inhibiting binding of endogenous IL-2, but their interaction with γc was weakened, attenuating IL-2Rβ-γc heterodimerization. These IL-2 analogs acted as partial agonists and differentially affected lymphocytes poised at distinct activation thresholds. Moreover, one variant, H9-RETR, antagonized IL-2 and IL-15 better than blocking antibodies against IL-2Rα or IL-2Rβ. Furthermore, this mutein prolonged survival in a model of graft-versus-host disease and blocked spontaneous proliferation of smoldering adult T cell leukemia (ATL) T cells. This receptor-clamping approach might be a general mechanism-based strategy for engineering cytokine partial agonists for therapeutic immunomodulation.

Ninomiya S, Narala N, Huye L, et al.
Tumor indoleamine 2,3-dioxygenase (IDO) inhibits CD19-CAR T cells and is downregulated by lymphodepleting drugs.
Blood. 2015; 125(25):3905-16 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Although T cells expressing CD19-specific chimeric antigen receptors (CARs) are a promising new therapy for B-cell malignancies, objective responses are observed at lower frequencies in patients with lymphoma than in those with acute B-cell leukemia. We postulated that the tumor microenvironment suppresses CAR-expressing T cells (CARTs) through the activity of indoleamine 2,3-dioxygenase (IDO), an intracellular enzyme that converts tryptophan into metabolites that inhibit T -: cell activity. To investigate the effects of tumor IDO on CD19-CART therapy, we used a xenograft lymphoma model expressing IDO as a transgene. CD19-CARTs inhibited IDO-negative tumor growth but had no effect on IDO-positive tumors. An IDO inhibitor (1-methyl-tryptophan) restored IDO-positive tumor control. Moreover, tryptophan metabolites inhibited interleukin (IL)-2-, IL-7-, and IL-15-dependent expansion of CARTs; diminished their proliferation, cytotoxicity, and cytokine secretion in vitro in response to CD19 recognition; and increased their apoptosis. Inhibition of CD19-CARTs was not mitigated by the incorporation of costimulatory domains, such as 4-1BB, into the CD19-CAR. Finally, we found that fludarabine and cyclophosphamide, frequently used before CART administration, downregulated IDO expression in lymphoma cells and improved the antitumor activity of CD19-CART in vivo. Because tumor IDO inhibits CD19-CARTs, antagonizing this enzyme may benefit CD19-CART therapy.

Komura T, Sakai Y, Harada K, et al.
Inflammatory features of pancreatic cancer highlighted by monocytes/macrophages and CD4+ T cells with clinical impact.
Cancer Sci. 2015; 106(6):672-86 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Pancreatic ductal adenocarcinoma (PDAC) is among the most fatal of malignancies with an extremely poor prognosis. The objectives of this study were to provide a detailed understanding of PDAC pathophysiology in view of the host immune response. We examined the PDAC tissues, sera, and peripheral blood cells of PDAC patients using immunohistochemical staining, the measurement of cytokine/chemokine concentrations, gene expression analysis, and flow cytometry. The PDAC tissues were infiltrated by macrophages, especially CD33+CD163+ M2 macrophages and CD4+ T cells that concomitantly express programmed cell death-1 (PD-1). Concentrations of interleukin (IL)-6, IL-7, IL-15, monocyte chemotactic protein-1, and interferon-γ-inducible protein-1 in the sera of PDAC patients were significantly elevated. The gene expression profile of CD14+ monocytes and CD4+ T cells was discernible between PDAC patients and healthy volunteers, and the differentially expressed genes were related to activated inflammation. Intriguingly, PD-1 was significantly upregulated in the peripheral blood CD4+ T cells of PDAC patients. Correspondingly, the frequency of CD4+PD-1+ T cells was increased in the peripheral blood cells of PDAC patients, and this increase correlated to chemotherapy resistance. In conclusion, inflammatory conditions in both PDAC tissue and peripheral blood cells in PDAC patients were prominent, highlighting monocytes/macrophages as well as CD4+ T cells with influence of the clinical prognosis.

Wang W, Li R, Meng M, et al.
MicroRNA profiling of CD3+ CD56+ cytokine-induced killer cells.
Sci Rep. 2015; 5:9571 [PubMed] Related Publications
Studies have proven that IL-2 and IL-15 showed contrasting roles during CIK cells preparation. By employing microarray, we analyzed miRNA expression profiles of PBMC, CIKIL-2 and CIKIL-15. Advanced bioinformatic analyses were performed to explore the key miRNAs which may regulate cell proliferation and anti-tumor activity of CIK. We identified 261 differentially expressed miRNAs (DEMs) between PBMC and CIKIL-2, and 249 DEMs between PBMC and CIKIL-15. MiR-143-3p/miR-145-5p was miRNA cluster which may positively regulate cell proliferation. In contrast, miR-340-5p/miR-340-3p cluster may negatively regulate cell proliferation via induction apoptosis, which may cause decreased cell proliferation capacity of CIKIL-2. MiRNA-target interaction analysis indicated that 10 co-downregulated miRNAs may synergistically turn on the expression of a pool of tumor cytotoxic genes in CIK cells. The DEMs between CIKIL-2 and CIKIL-15 may contribute to enhanced tumor cytotoxic capacity of CIKIL-2. Importantly, we found that repressed miR-193a-5p may regulate the expressions of inhibitory receptor KLRD1. The results of the validation assay have shown that KLRD1 were upregulated in CIK cells. Our findings have provided new insights into mechanisms of CIK cells production and tumor cytotoxic function, and shed light on their safety for clinical trial.

Erlach KC, Reddehase MJ, Podlech J
Mechanism of tumor remission by cytomegalovirus in a murine lymphoma model: evidence for involvement of virally induced cellular interleukin-15.
Med Microbiol Immunol. 2015; 204(3):355-66 [PubMed] Related Publications
A murine model of B and T cell lymphomas in recipients after hematoablative conditioning for hematopoietic cell transplantation (HCT) has previously revealed a tumor-repressive, metastasis-inhibiting function of murine cytomegalovirus (mCMV). More recently, this prediction from the experimental model was put on trial in several clinical studies that indeed gave evidence for a lower incidence of tumor relapse associated with early reactivation of latent human cytomegalovirus (hCMV) after allogeneic HCT in patients treated against different types of hematopoietic malignancies, including lymphoma and acute as well as chronic leukemias. Due to the limitations inherent to clinical studies, the tumor-repressive role of hCMV remained observational with no approach to clarify mechanisms. Although the tumor-repressive mechanisms of mCMV and hCMV may differ and depend on the type of tumor, experimental approaches in the murine model might give valuable hints for concepts to follow in clinical research. We have previously shown for the liver-adapted A20-derived B cell lymphoma E12E that mCMV does not infect the lymphoma cells for causing cell death by viral cytopathogenicity but triggers tumor-selective apoptosis at a tissue site of tumor metastasis distant from a local site of infection. This finding suggested involvement of a cytokine that triggers apoptosis, directly or indirectly. Here we used a series of differential high-density microarray analyses to identify cellular genes whose expression is specifically upregulated at the site of virus entry only by viruses capable of triggering lymphoma cell apoptosis. This strategy identified interleukin-15 (IL-15) as most promising candidate, eventually confirmed by lymphoma repression with recombinant IL-15.

Katano I, Takahashi T, Ito R, et al.
Predominant development of mature and functional human NK cells in a novel human IL-2-producing transgenic NOG mouse.
J Immunol. 2015; 194(7):3513-25 [PubMed] Related Publications
We generated a severe immunodeficient NOD/Shi-scid-IL-2Rγ(null) (NOG) mouse substrain expressing the transgenic human IL-2 gene (NOG-IL-2 Tg). Upon transfer of human cord blood-derived hematopoietic stem cells (HSCs), CD3(-)CD56(high)CD16(+/-) cells developed unexpectedly, predominantly in the NOG-IL-2 Tg (hu-HSC NOG-IL-2 Tg). These cells expressed various NK receptors, including NKp30, NKp44, NKp46, NKG2D, and CD94, as well as a diverse set of killer cell Ig-like receptor molecules at levels comparable to normal human NK cells from the peripheral blood, which is evidence of their maturity. They produced levels of granzyme A as high as in human peripheral blood-derived NK cells, and a considerable amount of perforin protein was detected in the plasma. Human NK cells in hu-HSC NOG-IL-2 Tg produced IFN-γ upon stimulation, and IL-2, IL-15, or IL-12 treatment augmented the in vitro cytotoxicity. Inoculation of K562 leukemia cells into hu-HSC NOG-IL-2 Tg caused complete rejection of the tumor cells, whereas inoculation into hu-HSC NOG fully reconstituted with human B, T, and some NK cells did not. Moreover, when a CCR4(+) Hodgkin's lymphoma cell line was inoculated s.c. into hu-HSC NOG-IL-2 Tg, the tumor growth was significantly suppressed by treatment with a therapeutic humanized anti-CCR4 Ab (mogamulizumab), suggesting that the human NK cells in the mice exerted active Ab-dependent cellular cytotoxicity in vivo. Taken together, these data suggest that the new NOG-IL-2 Tg strain is a unique model that can be used to investigate the biological and pathological functions of human NK cells in vivo.

Yan Y, Li S, Jia T, et al.
Combined therapy with CTL cells and oncolytic adenovirus expressing IL-15-induced enhanced antitumor activity.
Tumour Biol. 2015; 36(6):4535-43 [PubMed] Related Publications
Addition of immunoregulation factor to an oncolytic adenovirus being constructed is a developmental step in tumor gene therapy; however, cytokine IL-15 has not been frequently used as a potential cancer therapy agent. Here, we constructed an E2F-1 promoter oncolytic adenovirus based on type 5 adenovirus, which induces viral replication and proliferation in targeted tumor cells. We inserted the IL-15 gene into the E3 region of the model and found that human IL-15 expressing oncolytic adenovirus (Ad-E2F/IL15) shows a more intense antitumor effect than simple oncolytic viruses (Ad-E2F) do. Precisely because IL-15 can activate natural killer (NK) cells, CD8(+)T cells, and other immune cells, in antitumor therapy, Ad-E2F/IL15 was used in combination with cytotoxic T lymphocytes (CTL) to create a virus that can induce IL-15 gene expression while lysing tumors and stimulating the activity and function of adoptive immune cells. The therapeutic effect of this therapy is clearly stronger than that of a single application of oncolytic viruses or CTL, and hence, it could be a potential new tumor therapy.

Holmes TD, Wilson EB, Black EV, et al.
Licensed human natural killer cells aid dendritic cell maturation via TNFSF14/LIGHT.
Proc Natl Acad Sci U S A. 2014; 111(52):E5688-96 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Interactions between natural killer (NK) cells and dendritic cells (DCs) aid DC maturation and promote T-cell responses. Here, we have analyzed the response of human NK cells to tumor cells, and we identify a pathway by which NK-DC interactions occur. Gene expression profiling of tumor-responsive NK cells identified the very rapid induction of TNF superfamily member 14 [TNFSF14; also known as homologous to lymphotoxins, exhibits inducible expression, and competes with HSV glycoprotein D for HVEM, a receptor expressed by T lymphocytes (LIGHT)], a cytokine implicated in the enhancement of antitumor responses. TNFSF14 protein expression was induced by three primary mechanisms of NK cell activation, namely, via the engagement of CD16, by the synergistic activity of multiple target cell-sensing NK-cell activation receptors, and by the cytokines IL-2 and IL-15. For antitumor responses, TNFSF14 was preferentially produced by the licensed NK-cell population, defined by the expression of inhibitory receptors specific for self-MHC class I molecules. In contrast, IL-2 and IL-15 treatment induced TNFSF14 production by both licensed and unlicensed NK cells, reflecting the ability of proinflammatory conditions to override the licensing mechanism. Importantly, both tumor- and cytokine-activated NK cells induced DC maturation in a TNFSF14-dependent manner. The coupling of TNFSF14 production to tumor-sensing NK-cell activation receptors links the tumor immune surveillance function of NK cells to DC maturation and adaptive immunity. Furthermore, regulation by NK cell licensing helps to safeguard against TNFSF14 production in response to healthy tissues.

Szmania S, Lapteva N, Garg T, et al.
Ex vivo-expanded natural killer cells demonstrate robust proliferation in vivo in high-risk relapsed multiple myeloma patients.
J Immunother. 2015; 38(1):24-36 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
Highly activated/expanded natural killer (NK) cells can be generated by stimulation with the human leukocyte antigen-deficient cell line K562, genetically modified to express 41BB-ligand and membrane-bound interleukin (IL)15. We tested the safety, persistence, and activity of expanded NK cells generated from myeloma patients (auto-NK) or haploidentical family donors (allo-NK) in heavily pretreated patients with high-risk relapsing myeloma. The preparative regimen comprised bortezomib only or bortezomib and immunosuppression with cyclophosphamide, dexamethasone, and fludarabine. NK cells were shipped overnight either cryopreserved or fresh. In 8 patients, up to 1×10⁸ NK cells/kg were infused on day 0 and followed by daily administrations of IL2. Significant in vivo expansion was observed only in the 5 patients receiving fresh products, peaking at or near day 7, with the highest NK-cell counts in 2 subjects who received cells produced in a high concentration of IL2 (500 U/mL). Seven days after infusion, donor NK cells comprised >90% of circulating leukocytes in fresh allo-NK cell recipients, and cytolytic activity against allogeneic myeloma targets was retained in vitro. Among the 7 evaluable patients, there were no serious adverse events that could be related to NK-cell infusion. One patient had a partial response and in another the tempo of disease progression decreased; neither patient required further therapy for 6 months. In the 5 remaining patients, disease progression was not affected by NK-cell infusion. In conclusion, infusion of large numbers of expanded NK cells was feasible and safe; infusing fresh cells was critical to their expansion in vivo.

Cao S, Strong MJ, Wang X, et al.
High-throughput RNA sequencing-based virome analysis of 50 lymphoma cell lines from the Cancer Cell Line Encyclopedia project.
J Virol. 2015; 89(1):713-29 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
UNLABELLED: Using high-throughput RNA sequencing data from 50 common lymphoma cell culture models from the Cancer Cell Line Encyclopedia project, we performed an unbiased global interrogation for the presence of a panel of 740 viruses and strains known to infect human and other mammalian cells. This led to the findings of previously identified infections by Epstein-Barr virus (EBV), Kaposi's sarcoma herpesvirus (KSHV), and human T-lymphotropic virus type 1 (HTLV-1). In addition, we also found a previously unreported infection of one cell line (DEL) with a murine leukemia virus. High expression of murine leukemia virus (MuLV) transcripts was observed in DEL cells, and we identified four transcriptionally active integration sites, one being in the TNFRSF6B gene. We also found low levels of MuLV reads in a number of other cell lines and provided evidence suggesting cross-contamination during sequencing. Analysis of HTLV-1 integrations in two cell lines, HuT 102 and MJ, identified 14 and 66 transcriptionally active integration sites with potentially activating integrations in immune regulatory genes, including interleukin-15 (IL-15), IL-6ST, STAT5B, HIVEP1, and IL-9R. Although KSHV and EBV do not typically integrate into the genome, we investigated a previously identified integration of EBV into the BACH2 locus in Raji cells. This analysis identified a BACH2 disruption mechanism involving splice donor sequestration. Through viral gene expression analysis, we detected expression of stable intronic RNAs from the EBV BamHI W repeats that may be part of long transcripts spanning the repeat region. We also observed transcripts at the EBV vIL-10 locus exclusively in the Hodgkin's lymphoma cell line, Hs 611.T, the expression of which were uncoupled from other lytic genes. Assessment of the KSHV viral transcriptome in BCP-1 cells showed expression of the viral immune regulators, K2/vIL-6, K4/vIL-8-like vCCL1, and K5/E2-ubiquitin ligase 1 that was significantly higher than expression of the latency-associated nuclear antigen. Together, this investigation sheds light into the virus composition across these lymphoma model systems and provides insights into common viral mechanistic principles.
IMPORTANCE: Viruses cause cancer in humans. In lymphomas the Epstein-Barr virus (EBV), Kaposi's sarcoma herpesvirus (KSHV) and human T-lymphotropic virus type 1 are major contributors to oncogenesis. We assessed virus-host interactions using a high throughput sequencing method that facilitates the discovery of new virus-host associations and the investigation into how the viruses alter their host environment. We found a previously unknown murine leukemia virus infection in one cell line. We identified cellular genes, including cytokine regulators, that are disrupted by virus integration, and we determined mechanisms through which virus integration causes deregulation of cellular gene expression. Investigation into the KSHV transcriptome in the BCP-1 cell line revealed high-level expression of immune signaling genes. EBV transcriptome analysis showed expression of vIL-10 transcripts in a Hodgkin's lymphoma that was uncoupled from lytic genes. These findings illustrate unique mechanisms of viral gene regulation and to the importance of virus-mediated host immune signaling in lymphomas.

Van den Bergh JM, Van Tendeloo VF, Smits EL
Interleukin-15: new kid on the block for antitumor combination therapy.
Cytokine Growth Factor Rev. 2015; 26(1):15-24 [PubMed] Related Publications
Interleukin (IL)-15 is one of the most promising molecules to be used in antitumor immune therapy, as it is able to stimulate the main killer cells of both the innate and adaptive immune system. Although this cytokine can be used as a stand-alone immunotherapeutic agent, IL-15 will probably be most efficient in combination with other strategies to overcome high tumor burden, immune suppression of the tumor microenvironment and/or the short half-life of IL-15. In this review, we will discuss the combination strategies with IL-15 that have been tested to date in different animal tumor models, which include chemotherapy, other immunostimulatory cytokines, targeted therapy, adoptive cell transfer and gene therapy. In addition, we give an overview of IL-15 combination therapies that are currently tested in clinical studies to treat patients with hematological or advanced solid tumors.

Forget MA, Malu S, Liu H, et al.
Activation and propagation of tumor-infiltrating lymphocytes on clinical-grade designer artificial antigen-presenting cells for adoptive immunotherapy of melanoma.
J Immunother. 2014 Nov-Dec; 37(9):448-60 [PubMed] Article available free on PMC after 01/04/2017 Related Publications
PURPOSE: Adoptive cell therapy with autologous tumor-infiltrating lymphocytes (TIL) is a therapy for metastatic melanoma with response rates of up to 50%. However, the generation of the TIL transfer product is challenging, requiring pooled allogeneic normal donor peripheral blood mononuclear cells (PBMC) used in vitro as "feeders" to support a rapid-expansion protocol. Here, we optimized a platform to propagate TIL to a clinical scale using K562 cells genetically modified to express costimulatory molecules such as CD86, CD137-ligand, and membrane-bound IL-15 to function as artificial antigen-presenting cells (aAPC) as an alternative to using PBMC feeders.
EXPERIMENTAL DESIGN: We used aAPC or γ-irradiated PBMC feeders to propagate TIL and measured rates of expansion. The activation and differentiation state was evaluated by flow cytometry and differential gene expression analyses. Clonal diversity was assessed on the basis of the pattern of T-cell receptor usage. T-cell effector function was measured by evaluation of cytotoxic granule content and killing of target cells.
RESULTS: The aAPC propagated TIL at numbers equivalent to that found with PBMC feeders, whereas increasing the frequency of CD8 T-cell expansion with a comparable effector-memory phenotype. mRNA profiling revealed an upregulation of genes in the Wnt and stem-cell pathways with the aAPC. The aAPC platform did not skew clonal diversity, and CD8 T cells showed comparable antitumor function as those expanded with PBMC feeders.
CONCLUSIONS: TIL can be rapidly expanded with aAPC to clinical scale generating T cells with similar phenotypic and effector profiles as with PBMC feeders. These data support the clinical application of aAPC to manufacture TIL for the treatment of melanoma.

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