Antitumor activity of interleukin-18 against the murine T-cell leukemia/lymphoma EL-4 in syngeneic mice

Combination of NKT14m and Low Dose IL-12 Promotes Invariant Natural Killer T Cell IFN-γ Production and Tumor Control

Invariant natural killer T (iNKT) cells are innate-like T lymphocytes characterized by the expression of an invariant T cell receptor (iTCR) that recognizes glycolipid antigens presented by the MHC I-like CD1d molecule. Following antigenic stimulation, iNKT cells rapidly produce large amounts of cytokines that can trans-activate dendritic cells (DC) and promote the anti-tumor functions of cytotoxic lymphocytes, such as natural killer (NK) and CD8 T cells. Additionally, iNKT cells can mediate robust and direct cytotoxicity against CD1d⁺ tumor targets. However, many tumors down-regulate CD1d and evade iNKT cell attack. To circumvent this critical barrier to iNKT cell anti-tumor activity, a novel monoclonal antibody (mAb), NKT14 has been recently developed. This agonistic antibody binds directly and specifically to the iTCR of murine iNKT cells. In the current study, we demonstrate that NKT14m mediates robust activation, cytokine production and degranulation of murine iNKT cells, in vitro. Consistently, NKT14m also promoted iNKT cell activation and immunomodulatory functions, in vivo. Finally, administration of NKT14m with low dose interleukin (IL)-12 further augmented iNKT cell IFN-γ production in vivo, and this combination conferred superior suppression of tumor cell growth compared to NKT14m or IL-12 alone. Together, these data demonstrate that a combination treatment consisting of low dose IL-12 and iTCR-specific mAb may be an attractive alternative to activate iNKT cell anti-tumor functions.

Functional genetic variability at promoters of pro-(IL-18) and anti-(IL-10) inflammatory affects their mRNA expression and survival in prostate carcinoma patients: Five year follow-up study

BACKGROUND

Inflammation is an important hallmark of all cancers. The net inflammatory response is determined by a delicate balance between pro- and anti-inflammatory cytokines, which, in turn, is determined by the genetic make-up. The present study investigates the role of variations in the promoter regions of IL-18 and IL-10 (anti-inflammatory) cytokines on mRNA expressions and survival in prostate cancer (PCa) patients.

METHODS

The study was conducted on 584 volunteer males (291 patients of PCa, between 40-80 years of age. Genetic variants were studied by using RFLP and confirmed by probe based method. Expressions of mRNA were evaluated by real-time PCR (Roche light cycler 480). Relative mRNA and fold change gene expressions were analyzed by ([1/2] (ΔCt) ) and (2(-ΔΔCt) ) methods, respectively, and 5 year follow-ups were evaluated by Log-rank (Mantel-Cox) test with Log-rank test for trends.

RESULTS

IL-18 mRNA expression was significantly elevated in GG genotypes (at -137) of PCa with relative mRNA expression of 13.95, that is, 8.48 folds higher (P < 0.05) than controls; and showed a significant median survival of 1243 days. The CC genotypes of IL-10 at both loci (-819 T/C and -592C/A) showed 3.63 and 3.52 higher relative mRNA expressions than controls, but poor survival of 984 and 1052 days than TT of 1359 days and AA of 1371 days.

CONCLUSIONS

Genetic variants of pro-inflammatory IL-18 which showed higher relative mRNA expressions have better survival. Genetic variants of anti-inflammatory IL-10 with higher relative mRNA expression showed decreased chances of survival.

Genetic variability at promoters of IL-18 (pro-) and IL-10 (anti-) inflammatory gene affects susceptibility and their circulating serum levels: An explorative study of prostate cancer patients in North Indian populations

Inflammation is an important hallmark of all types of cancers with a well-established role in carcinogenesis. The net inflammatory response is determined by the balance between pro- and anti-inflammatory cytokines, the levels of which may be affected by the genetic make-up. Interleukin (IL)-18, a pro-inflammatory cytokine expressed by various cells including those of the prostate, is a key mediator of anti-cancer immune response. IL-10, an anti-inflammatory cytokine associated with tumour malignancy, causes escape from immune surveillance. This study hypothesizes that genetic variants of IL-18 (-607 C/A and -137 G/T) and IL-10 (-819 C/T and -592 C/A) may influence the circulating levels of these interleukins, thereby generating susceptibility risk to prostate cancer. The study was conducted on 676 subjects (controls and patients of prostate cancer (PCa): 291 each; and 94 patients with benign prostate hypertrophy (BPH)). Genotyping was performed by PCR-RFLP and Real-Time PCR probe-based method. Circulating interleukin levels were obtained by ELISA. Circulating IL-18 levels were significantly elevated in cancer and BPH patients carrying GG genotypes for -137 of IL-18. The trend of circulating IL-18 levels was GG>GC>CC, observed in all groups. The -137 genetic variants of IL-18 significantly associated with PCa risk were GC, CC, and GC+CC, compared to GG (OR: 1.71, 95% CI: 1.20-2.46; OR: 3.35, 95% CI: 2.03-5.53; and OR: 2.05, 95% CI: 1.46-2.87, respectively). A significant association of AA and CA+AA against CC genotype was observed at -607 locus of IL-18 (OR: 0.46, 95%CI: 0.29-0.72; OR: 0.61, 95% CI: 0.41-0.90, respectively). Significantly elevated levels of IL-10 were observed with TT (wild) genotype at -819 of IL-10, compared to the CC (homozygous mutant) genotype in all three groups of subjects. However, no significant association was found between IL-10 promoter genotypes and PCa risk. We conclude that genetic variants of IL-18 and IL-10 promoters influence the circulating levels of these interleukins. Variations at -137 and -607 loci of IL-18 are associated with susceptibility to PCa.

Interleukin 18: friend or foe in cancer

In the last few years, the field of tumor immunology has significantly expanded and its boundaries, never particularly clear, have become less distinct. Although the immune system plays an important role in controlling tumor growth, it has also become clear that tumor growth can be promoted by inflammatory immune responses. A good example that exemplifies the ambiguous role of the immune system in cancer progression is represented by interleukin 18 (IL-18) that was first identified as an interferon-γ-inducing factor (IGIF) involved in T helper type-1 (Th1) immune response. The expression and secretion of IL-18 have been observed in various cell types from immune cells to circulating cancer cells. In this review we highlighted the multiple roles played by IL-18 in immune regulation, cancer progression and angiogenesis and the clinical potential that may result from such understanding.

Investigation of PEG-PLGA-PEG nanoparticles-based multipolyplexes for IL-18 gene delivery

Nanoparticles were formulated with biodegradable monomethoxy (poly ethylene glycol)-poly(lactide-co-glycolide)-monomethoxy (poly ethylene glycol) of three different proportional (PEG-PLGA-PEG, lactic acid: glycolic acid = 80/20, 70/30, 50/50) and the cytotoxicity of nanoparticle was characterized according to US Pharmacopoeia XXIII recommendations on various cell lines, including L929, Chang's hepatocytes, primary mouse myoblasts, osteoblasts, and renal vascular endothelial cells. mIL-18 gene was first condensed by polycationic peptide polylysine (PLL), and then encapsulated in the PEG-PLGA-PEG NPs as a novel multi-polyplex gene delivery system - Polymer-PLL-DNA. (PPDs) After lyopholization, the morphology, particle size, zeta potential, and the integrity of DNA in the NPs were investigated. The expression of mIL-18 gene on CT-26 cells in vitro were determined by western blot, while in vivo efficacy was evaluated by tumor inhibition rate, histological section, and survival curve in pulmonary metastasis of colon cancer in BALB/c mice model. Results showed that the cytotoxicity of blank nanoparticles was related to the degradation properties of the polymers with different compositions. The NPs with LA:GA = 70/30 (NPs-73) was optimal for intravenous injection due to its low cytotoxicity. Physicochemical properties of the PPDs were not changed during the lyopholization, while mIL-18 was successfully expressed in vitro. The anti-tumor efficacy in vivo of PPDs showed improvement especially combined with chemotherapy of cisplatin, and confirmed the promising application of the PPDs system, which compared with any single treatment.

Oncolytic adenovirus expressing interleukin-18 induces significant antitumor effects against melanoma in mice through inhibition of angiogenesis

It has been shown that interleukin 18 (IL-18) exerts antitumor activity. In this study, we investigated whether oncolytic adenovirus-mediated gene transfer of IL-18 could induce strong antitumor activity. A tumor-selective replicating adenovirus expressing IL-18 (ZD55-IL-18) was constructed by insertion of an IL-18 expression cassette into the ZD55 vector, which is based on deletion of the adenoviral E1B 55-kDa gene. It has been shown that ZD55-IL-18 exerted a strong cytopathic effect and significant apoptosis in tumor cells. ZD55-IL-18 significantly decreased vascular endothelial growth factor and CD34 expression in the melanoma cells. Treatment of established tumors with ZD55-IL-18 showed much stronger antitumor activity than that induced by ZD55-EGFP (enhanced green fluorescent protein) or Ad-IL-18. These data indicated that oncolytic adenovirus expressing IL-18 could exert potential antitumor activity through inhibition of angiogenesis and offer a novel approach to melanoma therapy.

Identification of transcripts modulated by ETV6 expression

Deletions at chromosome 12p12-13 are observed in 26-47% of childhood pre-B acute lymphoblastic leukaemia (ALL) cases, suggesting the presence of a tumour suppressor gene (TSG). Accumulating genetic and functional evidence points to ETV6 as being the most probable TSG targeted by the deletions. ETV6 is a ubiquitously expressed transcription factor of the ETS family with very few known targets. To understand its function and to elucidate the impact of its absence in leukaemia, we conducted a study to identify targeted genes. Following the induction of ETV6 expression, global expression was evaluated at different time points. We identified 87 modulated genes, of which 10 (AKR1C1, AKR1C3, IL18, LUM, PHLDA1, PTGER4, PTGS2, SPHK1, TP53 and VEGF) were validated by real-time quantitative reverse transcription-polymerase chain reaction. To assess the significance of the validated candidate genes in leukaemia, their expression patterns were determined, as well as that of ETV6, in pre-B ALL patients. The expression of IL18, LUM, PTGER4, SPHK1 and TP53 was significantly correlated with that of ETV6, further suggesting that ETV6 could regulate the expression of these genes in leukaemia. This work constitutes another step towards the understanding of the functions of ETV6 and the impact of its inactivation in childhood leukaemia.

Interleukins 18 and 21: biology, mechanisms of action, toxicity, and clinical activity

Interleukins 18 and 21 have been described, and the effect of each upon immune response and experimental tumors in animals has been the subject of much recent work. Both interleukins have shown antitumor effects in animals, which in some models are striking for their duration, specificity, and ability to protect against rechallenge with the same tumor. These characteristics suggest immunologic involvement in the antitumor response, and several papers suggest involvement of both innate and adaptive immune mechanisms. Recent early phase I clinical trials in human cancer patients have demonstrated evidence of clinical response. This review discusses the biology, preclinical animal tumor model data, and early clinical trial findings.

TYK2 is a key regulator of the surveillance of B lymphoid tumors

Aberrant activation of the JAK-STAT pathway has been implicated in tumor formation; for example, constitutive activation of JAK2 kinase or the enforced expression of STAT5 induces leukemia in mice. We show here that the Janus kinase TYK2 serves an opposite function. Mice deficient in TYK2 developed Abelson-induced B lymphoid leukemia/lymphoma as well as TEL-JAK2-induced T lymphoid leukemia with a higher incidence and shortened latency compared with WT controls. The cell-autonomous properties of Abelson murine leukemia virus-transformed (A-MuLV-transformed) TYK2(-/-) cells were unaltered, but the high susceptibility of TYK2(-/-) mice resulted from an impaired tumor surveillance, and accordingly, TYK2(-/-) A-MuLV-induced lymphomas were easily rejected after transplantation into WT hosts. The increased rate of leukemia/lymphoma formation was linked to a decreased in vitro cytotoxic capacity of TYK2(-/-) NK and NKT cells toward tumor-derived cells. RAG2/TYK2 double-knockout mice succumbed to A-MuLV-induced leukemia/lymphoma faster than RAG2(-/-)TYK2(+/-) mice. This defines NK cells as key players in tumor surveillance in Abelson-induced malignancies. Our observations provide compelling evidence that TYK2 is an important regulator of lymphoid tumor surveillance.

TYK2 is a key regulator of the surveillance of B lymphoid tumors

Aberrant activation of the JAK-STAT pathway has been implicated in tumor formation; for example, constitutive activation of JAK2 kinase or the enforced expression of STAT5 induces leukemia in mice. We show here that the Janus kinase TYK2 serves an opposite function. Mice deficient in TYK2 developed Abelson-induced B lymphoid leukemia/lymphoma as well as TEL-JAK2-induced T lymphoid leukemia with a higher incidence and shortened latency compared with WT controls. The cell-autonomous properties of Abelson murine leukemia virus-transformed (A-MuLV-transformed) TYK2(-/-) cells were unaltered, but the high susceptibility of TYK2(-/-) mice resulted from an impaired tumor surveillance, and accordingly, TYK2(-/-) A-MuLV-induced lymphomas were easily rejected after transplantation into WT hosts. The increased rate of leukemia/lymphoma formation was linked to a decreased in vitro cytotoxic capacity of TYK2(-/-) NK and NKT cells toward tumor-derived cells. RAG2/TYK2 double-knockout mice succumbed to A-MuLV-induced leukemia/lymphoma faster than RAG2(-/-)TYK2(+/-) mice. This defines NK cells as key players in tumor surveillance in Abelson-induced malignancies. Our observations provide compelling evidence that TYK2 is an important regulator of lymphoid tumor surveillance.

Heterogeneous expression of interleukin-18 and its receptor in B-cell lymphoproliferative disorders deriving from naive, germinal center, and memory B lymphocytes

PURPOSE

Dysregulated cytokine/cytokine receptor expression may occur in B-cell lymphoproliferative disorders. Little information is available on interleukin-18 receptor (IL-18R) and IL-18 expression in normal and malignant B cells. Our purpose was to investigate this issue in human naive, germinal center (GC) and memory B cells, and in their neoplastic counterparts.

EXPERIMENTAL DESIGN

We have evaluated IL-18 expression and production in tonsil naive, GC, and memory B cells and in their presumed neoplastic counterparts by reverse transcription-PCR and ELISA. Moreover, IL-18Ralpha and beta expression was investigated in the same cells by reverse transcription-PCR, flow cytometry, and immunohistochemistry.

RESULTS

We found that: (a) IL-18 mRNA was expressed in tonsil naive, GC, and memory B cells. Bioactive IL-18 was secreted by naive and GC, but not by memory B cells; (b) IL-18Ralpha and beta transcripts were expressed in the three B-cell subsets. IL-18Ralpha was detected on the surface of naive, GC, and memory B lymphocytes, and IL-18Rbeta was detected on GC and memory, but not naive, B cells; (c) mantle zone, follicular, marginal zone, Burkitt lymphoma (BL), and B-cell chronic lymphocytic leukemia (B-CLL) cells expressed IL-18 mRNA. B-CLL and BL cells did not produce bioactive IL-18; and (d) lymphoma B cells displayed heterogeneous expression of either or both IL-18R chain mRNA. In contrast, B-CLL cells expressed both IL-18R chains at the mRNA and protein levels.

CONCLUSIONS

Dysregulated expression of IL-18 and/or IL-18R in chronic B-cell lymphoproliferative disorders may sometimes contribute to tumor escape from the host immune system.

Gene transfer of pro-IL-18 and IL-1β converting enzyme cDNA induces potent antitumor effects in L1210 cells

We report in a murine model of acute lymphoid leukemia L1210 the potent antitumor efficiency of a combinatorial delivery of pro-IL-18 gene modified L1210 (Lp18) and IL-1beta converting enzyme (ICE) gene modified L1210 (LpICE). Live leukemia cells Lp18 or Lp18 plus LpICE showed apparently reduced leukemogenicity with a survival rate of 40 or 50% at 50 days after intraperitoneal (i.p.) inoculation of a lethal dose of cells, respectively. Combination of Lp18 and LpICE was capable of inhibiting accumulation of bloody ascites, synergistically superior to Lp18 or LpICE alone. All surviving mice were rechallenged with parental L1210 cells at day 50, and all survived up to day 80, suggesting that gene-modified cells induced immune protection. Moreover, NK cytotoxicity and CTL activity were both enhanced in mice injected with Lp18, especially Lp18 plus LpICE. Levels of IFN-gamma were not altered significantly by inoculation of Lp18 or Lp18 plus LpICE. Our results demonstrate that IL-18 is a useful candidate gene in gene therapy of lymphoma or lymphoid leukemia, and ex vivo combinatorial delivery of Lp18 plus LpICE either as a single approach or as an adjunct to concomitant radiotherapy or chemotherapy, may be more efficient in a situation of minimal residual disease.

Suppression of thymic lymphomas and increased nonthymic lymphomagenesis inTrp53-deficient mice lacking inducible nitric oxide synthase gene

Trp53-deficient mice spontaneously develop lymphomas, mainly of thymic origin, although the molecular mechanism remains largely unknown. As several interaction effects between p53 and iNOS have been reported, we hypothesized that iNOS activity in the thymus is causally linked to lymphomagenesis in Trp53-deficient mice. We therefore created mouse strains with different combinations of the Trp53 and iNOS genes. Western blot and histologic analyses showed that the iNOS protein was constitutively expressed in the thymus independently of Trp53 status and its expression was enhanced in Trp53+/- and Trp53-/- mice compared to Trp53+/+ mice. Homozygous disruption of iNOS decreased the incidence of thymic lymphomas by almost 40% (p=0.087) and 90% (p<0.05) in Trp53-/- and Trp53+/- mice, respectively, compared to the respective iNOS wild-type mice but significantly (p<0.05) increased the development of nonthymic lymphomas in Trp53-/- and Trp53+/- mice. Although iNOS gene disruption did not affect the phenotype of thymic lymphomas, absence of the iNOS gene shifted the spectrum of nonthymic lymphoma from the B-cell to the T-cell lineage. RT-PCR analysis revealed enhanced expression of IL-10, which could have a promoting effect on lymphomagenesis, even without any stimulation, in the spleen of aging mice with the gene combinations Trp53-/-iNOS-/- and Trp53+/-iNOS-/- but not Trp53-/-iNOS+/+ or Trp53+/-iNOS+/+. These results suggest that iNOS could increase the development of thymic lymphomas in Trp53-deficient mice. While iNOS may have protective effects against nonthymic lymphomagenesis, the regulation of cytokine production by iNOS may be involved in the underlying mechanism of antilymphomagenesis effects in the peripheral lymphoid organ.

In vivo antitumor activity of NKT cells activated by the combination of IL-12 and IL-18

Interleukin-12 and IL-18 have been demonstrated to potentiate innate immunity in a variety of experimental tumor models, but the functional roles of NK and/or NKT cells and their mechanism of action in these models have not been fully addressed. Through adoptive transfer of NKT cells activated in vitro with a combination of IL-12 plus IL-18 (IL-12/IL-18 NKT) into syngeneic animals, we demonstrate in this study that IL-12/IL-18 NKT cells are essential and collaborate with the host's own NK cells in natural host immunity against the growth of ALC and MC57X syngeneic tumors. The relative roles of the adoptively transferred IL-12/IL-18 NKT cells and endogenous NK cells in host protection were first shown in normal C57BL/6 (B6) mice treated with anti-asialo GM1 Ab that selectively depletes NK cells; second, in B6.TCRJalpha281(-/-) mice specifically deficient for NKT cells; and third, in B6.scid mice that also lack NKT cells. Furthermore, by injecting normal B6 mice with anti-IL-2 and/or anti-IFN-gamma mAb, we could demonstrate that effective innate immunity against both types of syngeneic tumors was dependent on the production of IL-2 and IFN-gamma by the adoptively transferred NKT cells. In vitro studies confirmed both the secretion of IL-2 and IFN-gamma by the IL-12/IL-18-activated NKT cells and their collaborative role with NK cells for lysis of ALC and MC57X syngeneic tumor targets. This is the first description of an antitumor function of IL-12/IL-18 NKT cells adoptively transferred into syngeneic hosts that provides the basis for a new modality in the cellular immunotherapy of cancer.