Constitutive aberrant endogenous interleukin-1 facilitates inflammation and growth in human melanoma

Interleukin (IL)-1-mediated inflammation is proposed to contribute to the development and progression of some cancers. IL-1 family member proteins are known to be expressed constitutively in many melanoma tumor cells, and we hypothesize that these support molecular pathways of inflammation and facilitate tumor growth. To investigate the expression of IL-1α and IL-1β in melanoma patients, and their association with disease progression, immunohistochemical staining was carried out on tissues from 170 patients including benign nevi, primary melanomas, and metastatic melanomas. IL-1β levels were low (or zero) in benign nevi and higher in primary and metastatic melanomas (P < 0.0001). IL-1α was expressed in about 73% of nevi and 55% of metastatic melanomas, with levels significantly higher in primary tumors (P < 0.0001); most (98%) primary melanoma samples were positive for IL-1α. In vitro studies with seven human melanoma cell lines showed that five cell lines expressed IL-1α and IL-1β proteins and mRNA. We identified for the first time several important downstream signaling pathways affected by endogenous IL-1, including reactive oxygen and nitrogen species, COX-2, and phosphorylated NF-κB inhibitor (IκB) and stress-activated protein kinase/c-jun-NH(2)-kinase; all of which were decreased by siRNA to IL-1s. Downregulation of IL-1α, IL-1β, or MyD88 substantially increased p21 and p53 levels. Treatment with IL-1 receptor type I neutralizing antibody or IL-1 pathway-specific siRNAs led to growth arrest in IL-1-positive melanoma cells. Furthermore, blocking the IL-1 pathway increased autophagy in IL-1-positive melanoma cells. These results indicate that the endogenous IL-1 system is functional in most human melanoma and interrupting its signaling inhibits the growth of IL-1-positive melanoma cells.

Abstract 5051: Aberrant endogenous expression of IL-1 promote inflammation and growth in human melanoma

Chronic inflammation can facilitate the initiation and progression of malignancies through the production of cytokines and reactive oxidative species. The elevation of interleukin 1 (IL-1) signaling pathway has been observed in melanoma and proposed to drive critical aspects of survival, which is tested in this study. Immunohistochemistry staining for IL-1α and β were performed in 168 biopsy samples from melanoma patients, including 35 nevi, 57 primary and 76 metastatic melanomas. Although only 11.4% of melanoma samples are positive for IL-1β, all the nevus samples are negative. The positive IL-1β percentage and intensity are strongly correlated with advanced disease stage (p &lt; 0.0005 and 0.0002). 93.4% of melanomas and 64% of nevi were positive for IL-1α, with tumors showing significantly higher IL-1α intensity scores than nevi (p &lt; 0.007). Melanoma cell lines A375, WM793, WM35, and SB2 highly express IL-1α, IL-1β, and IL-1 receptor I (IL-1RI), but not MeWo and TXM1 confirmed by RT-PCR and western blot. Therefore, the high expression of IL-1α and/or β was significant in some melanoma tissues and cell lines, which may play a crucial role on the melanoma growth. We further investigated the aberrant IL-1 signaling pathway in two mutant B-Raf melanoma cell lines, A375 and WM793. In both cells, the siRNA knockdown of IL-1α, IL-1β, or MyD88 led to dramatic decreases (about 50%) in several important inflammatory markers, including the Cox-2 expression, the levels of total reactive oxygen and nitrogen species, and the levels of phoshorylated SAPK/JNK and IκB. Moreover, the decrease of IL-1α, IL-1β, or MyD88 levels caused significant increase of p21 and p53 levels. Luciferase assay showed that 100 ng/ml IL-1α and β could increase about 30% of iNOS promoter activity in both cells. Our data suggest that aberrant IL-1 signaling pathway can promote inflammation and oxidative stress in melanoma cells. The treatment of 2.5 μg/ml IL-1RI neutralization antibodies could inhibit 20∼30% of cell growth in A375 and WM793 cells in 72 hours, but did not affect the growth of normal melanocytes as comparing with control goat IgG. Consistently, the siRNA knockdown of IL-1α, IL-1β, or MyD88 inhibited cell growth by 40∼60% in A375, WM793, WM35, and SB2 cells with high IL-1α and β levels. For TXM1 and MeWo cells with lower levels of IL-1α and β, siRNA knockdown of IL-1 system genes did not show any significant inhibitory effects on cell growth. Notably, the inhibition of growth by the decrease of IL-1α, IL-1β, or MyD88 levels in A375 and WM793 cells is due to autophagy, which was confirmed by the increases of acidic vesicular organelles in acridine orange staining and the autophagy marker LC3B levels in western blot. Our studies strongly indicate that the interruption of IL-1 signaling pathway can lead to growth suppression in melanoma cells, which can be a promising therapeutic strategy to sub-group melanoma patients with constitutively high expression of IL-1α.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5051. doi:10.1158/1538-7445.AM2011-5051

Nonmyeloablative allogeneic stem cell transplantation in relapsed/refractory chronic lymphocytic leukemia: long-term follow-up, prognostic factors, and effect of human leukocyte histocompatibility antigen subtype on outcome

BACKGROUND

The role of nonmyeloablative allogeneic stem cell transplantation (NST) in the treatment of chronic lymphocytic leukemia (CLL) is not well established. The authors report on long-term experience with NST in relapsed/refractory CLL and define prognostic factors associated with outcome.

METHODS

The authors reviewed the outcome of 86 patients with relapsed/relapsed CLL enrolled in sequential NST protocols.

RESULTS

The median patient age was 58 years. Patients were heavily pretreated before transplantation, and 43 required immunomanipulation after NST for persistent or recurrent disease. Immunomanipulation included withdrawal of immunosuppression, rituximab, and step-wise donor lymphocyte infusions. Of 43 patients receiving immunomanipulation, 20 (47%) experienced a complete remission. Patients with human leukocyte antigen (HLA) genotype A1(+) /A2(-) /B44(-) were more likely to experience a complete remission (P = .0009), with rates of 9%, 36%, 50%, and 91%, respectively, for 0, 1, 2, and 3 of these HLA factors. This resulted in significant improvement in progression-free-survival rates of 68.2% at 5 years for patients with all 3 HLA factors. Overall, the estimated 5-year survival rate was 51%. In a multivariate model, a CD4 count of <100/mm(3) and a below normal serum immunoglobulin G level at study entry were associated with a short survival duration (P < .0001).

CONCLUSIONS

These results confirm the potential cure of relapsed/refractory CLL with NST and provide the first evidence that immunoglobulin G and CD4 levels are predictive of overall survival after NST in CLL and that human leukocyte antigen alleles predict response to immunomanipulation.

Abstract 4506: Elevated expression of IL-1 induces iNOS/NO production and inhibits IL-1Ra synthesis leading to progression of metastatic melanoma

Aberrant expression of proinflammatory IL-1 α and β and the overproduction of nitric oxide (NO) have been shown to promote the progression of some tumors. In previous studies, we had confirmed that inducible nitric oxide synthase (iNOS) was constitutively expressed in most advanced melanomas and highly correlated with poor patient survival. In order to determine whether the imbalance of IL-1 and its natural competitor IL-1 receptor antagonist (IL-1Ra) contributes to the upregulation of iNOS in metastatic melanoma, we initiated an investigation of the expression profile of IL-1 system genes in melanoma and the linkage between IL-1 and iNOS/NO signaling pathways. Immunohistochemistry staining of 38 biopsy samples from metastatic melanoma patients showed that 33 samples highly expressed IL-1α and/or IL-1β. Only 5 samples were negative for both IL-1α and IL-1β expression. RT-PCR confirmed that melanoma cell lines A375, WM793, WM35, and SB2 constitutively expressed high levels of IL-1, IL-1 receptor I (IL-1RI), and iNOS. However, in the same cell lines, there was no detectable IL-1Ra mRNA, which is known to maintain IL-1 balance in normal skin tissues. Our study suggests that the imbalance of IL-1 and IL-Ra is widespread in metastatic melanoma. The engagement of IL-1 and IL-1RI can induce several kinase cascades leading to the activation of SAPK/JNK and NF-κB, and it is well known that transcription of iNOS can be regulated by NF-κB. In our studies, siRNA knockdown of either IL-1α or MyD88 (an important adaptor for IL-1RI signal pathway) in WM375 and A375 led to a dramatic decrease in the phoshorylation of SAPK/JNK and IκB. Furthermore, an 80% decrease of iNOS expression in WM793 was observed after the siRNA knockdown of MyD88. We confirmed that upregulated IL-1 signal pathway can activate NF-κB and the iNOS transcription. Treatment with 200 μM 7-Nitroindazole, a NO synthase inhibitor, not only reduced NO production, but also induced over 50% inhibition of cell growth and a marked increase in IL-1Ra mRNA in WM793 and A375. This indicates that a high level of NO can inhibit the IL-1Ra expression in melanoma cells. Based on our data, we proposed an inflammatory dysfunction model to explain the development of melanoma. It proposes that the constitutive expression of IL-1 can inhibit IL-1Ra expression mediated by the upregulation of iNOS/NO production in melanoma. The constant inhibition of IL-1Ra expression by NO results in a cycle of kinase transduction cascades, which drives NF-κB and its downstream inflammatory genes (including iNOS) constitutively expressed in melanoma. Our studies cast new insight into the mechanism of the pathology of metastatic melanoma. Selective inhibition of iNOS and increasing IL-1Ra levels are promising therapeutic strategies to suppress the aberrant IL-1 inflammation pathway in melanoma.

Supported by MDACC SPORE in Melanoma CA093459.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4506.

Interleukin-24 overcomes temozolomide resistance and enhances cell death by down-regulation of O6-methylguanine-DNA methyltransferase in human melanoma cells

Melanoma is the most malignant of skin cancers, highly resistant to chemotherapy and radiotherapy. Temozolomide, a promising new derivative of dacarbazine, is currently being tested for treatment of metastatic melanoma. Resistance to alkylating agents such as temozolomide correlates with increased expression of DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT). Interleukin-24 (IL-24; mda-7) is a tumor suppressor cytokine that selectively inhibits tumor cell growth by inducing apoptosis and cell cycle arrest in melanoma cell lines and solid tumors. This tumor-selective activity has been observed in multiple preclinical animal models and in clinical trials. In this study, we analyzed the ability of Ad-IL-24 and its protein product, IL-24, to overcome temozolomide resistance in human melanoma cells. We have shown that Ad-IL-24 via exogenous IL-24 protein induces combinatorial synergy of temozolomide-induced cell killing in temozolomide-resistant melanoma cells by inhibition of MGMT. Neutralizing antibodies against IL-24 or its receptors significantly blocked the apoptotic activity of IL-24 + MGMT treatment. We show that accumulation of functional p53 is essential for IL-24-induced down-regulation of MGMT. Using either MGMT small interfering RNA, p53 small interfering RNA, or a p53 dominant-negative mutant to block MGMT protein expression resulted in increased sensitization to temozolomide. However, MGMT blockade in combination with IL-24 + temozolomide resulted in loss of combinatorial synergy, indicating that MGMT expression is required for the reversal of temozolomide resistance in melanoma cells. This study shows that IL-24 can play a significant role in overcoming temozolomide resistance and that the clinical efficacy of temozolomide may be improved by using a biochemotherapy combination with IL-24.

Human interleukin 24 (MDA-7/IL-24) protein kills breast cancer cells via the IL-20 receptor and is antagonized by IL-10

The melanoma differentiation-associated gene-7 (mda-7/IL-24) is a unique member of the interleukin 10 (IL-10) family of cytokines, with ubiquitous tumor cell pro-apoptotic activity. Recent data have shown that IL-24 is secreted as a glycosylated protein and functions as a pro-Th1 cytokine and as a potent anti-angiogenic molecule. In this study, we analyzed the activity of Ad-mda7 and its protein product, secreted IL-24, against human breast cancer cells. We show that Ad-mda7 transduction of human breast cancer cells results in G(2)/M phase cell cycle arrest and apoptotic cell death, which correlates with secretion of IL-24 protein. Neutralizing antibody against IL-24 significantly inhibited Ad-mda7 cytotoxicity. IL-24 and IL-10 both engage their cognate receptors on breast cancer cells resulting in phosphorylation and activation of STAT3, however, IL-10 receptor binding failed to induce cell killing, indicating that tumor cell killing by IL-24 is independent of STAT3 phosphorylation. Treatment with exogenous IL-24 induced apoptosis in breast cancer cells and this effect was abolished by addition of anti-IL-24 antibody or anti-IL-20R1, indicating that bystander cell killing is mediated via IL-24 binding to the IL-20R1/IL-20R2 heterodimeric receptor complex. Co-administration of the related cytokine IL-10 inhibited killing mediated by IL-24 and concomitantly inhibited IL-24 mediated up-regulation of the tumor suppressor proteins, p53 and p27(Kip1). In summary, we have defined a tumor-selective cytotoxic bystander role for secreted IL-24 protein and identified a novel receptor-mediated death pathway in breast cancer cells, wherein the related cytokines IL-24 and IL-10 exhibit antagonistic activity.

Heterozygosity or homozygosity for 2 HLA class II haplotypes predict favorable outcomes for renal cell carcinoma treated with cytokine therapy

PURPOSE

Durable responses to cytokine therapy occur in a small subset of patients with renal cell carcinoma. We determined if a common HLA genotype existed among these patients which might be associated with response and survival.

MATERIALS AND METHODS

The study population consisted of 80 patients with metastatic renal cell carcinoma who had received cytokine therapy. DNA obtained from these patients was used for high resolution typing of HLA A, B, C, DRB1, DQA1 and DQB1 alleles.

RESULTS

The class II alleles from patients with prolonged disease-free survival were predominantly composed of haplotype DRB1*0301/DQA1*0501/DQB1*0201 and DRB1*1501/DQA1*0102/DQB1*0602. The frequency of heterozygosity or homozygosity for these alleles was significantly greater in the good outcome group of patients than in those whose disease progressed during therapy. Heterozygosity or homozygosity at these loci was also associated with significant prolongation of survival.

CONCLUSIONS

We conclude that heterozygosity or homozygosity for the class II haplotypes DRB1*0301/DQA1*0501/DQB1*0201 and DRB1*1501/DQA1*0102/DQB1*0602 is associated with durable response and survival in patients with metastatic renal cell carcinoma treated with cytokine therapy.

The protein product of the tumor suppressor gene, melanoma differentiation-associated gene 7, exhibits immunostimulatory activity and is designated IL-24

The melanoma differentiation-associated gene 7 (mda-7) has been studied primarily in the context of its tumor suppressor activity. Although mda-7 has been designated as IL-24 based on its gene location in the IL-10 locus and its mRNA expression in leukocytes, no functional evidence supporting this cytokine designation exists. To further characterize MDA-7/IL-24 expression patterns in the human immune system, MDA-7/IL-24 protein levels were examined in human PBMC. MDA-7/IL-24 was detected in PHA- and LPS-stimulated whole PBMC lysate by Western blot and in PHA-activated CD56 and CD19 subsets by immunohistochemistry. The biological function of MDA-7/IL-24, secreted from Ad-MDA7-transfected HEK 293 cells, was assessed by examining the effect of MDA-7/IL-24 on the cytokine secretion profile of PBMC. Within 48 h MDA-7/IL-24 induced secretion of high levels of IL-6, TNF-alpha, and IFN-gamma and low levels of IL-1beta, IL-12, and GM-CSF from human PBMC as measured by ELISA. The MDA-7/IL-24-mediated induction of these Th1-type cytokines was inhibited by the addition of IL-10 to the PBMC cultures, suggesting that these two related protein family members may provide antagonistic functions. Therefore, because human blood leukocytes can be stimulated to produce MDA-7/IL-24, as well as respond to MDA-7/IL-24 by expressing secondary cytokines, MDA-7/IL-24 has the expression profile and major functional attributes that justify its designation as an IL.

Indirect recognition of porcine swine leukocyte Ag class I molecules expressed on islets by human CD4+ T lymphocytes

Xenotransplantation of porcine islets is considered a viable alternative treatment for type 1 diabetes mellitus. Therefore, we characterized human PBL responding to porcine islets both in vitro by coculture and in vivo using SCID mice reconstituted with human PBLs (HuPBL-SCID) and transplanted with porcine islets. T cell lines generated in vitro and graft-infiltrating T cells obtained from HuPBL-SCID mice were CD4+-proliferated specifically to porcine islets cultured with autologous APC. This proliferation was abrogated by an anti-human class II Ab. These T cell lines also proliferated to purified swine leukocyte Ag (SLA) class I molecules in the presence of self-APC, indicating that the primary xenoantigens recognized are peptides derived from SLA. This CD4+ T cell line lysed porcine islets but not splenocytes. CD4+ T cell clones with Th0, Th1, and Th2 cytokine profiles were isolated. The Th0 and Th1 clones lysed porcine islets, whereas the Th2 clone that secreted a large amount of IL-4 was not lytic. These results demonstrate that human T cells responding to porcine islets are primarily CD4+ and recognize porcine xenoantigens by the indirect Ag pathway presentation. These activated T cells produce cytokines that lyse islets. Furthermore, we demonstrate that the major porcine xenoantigens recognized are SLA class I molecules.

Allograft infiltrating cytotoxic T lymphocytes recognize kidney-specific human minor histocompatibility antigens

The role of minor histocompatibility antigens (mH) in allograft immunity has been proposed, but the nature of these antigens and their immunogenicity are not well understood. We have shown that tissue-specific cytolytic T lymphocytes (CTL) can be isolated form graft infiltrating lymphocyte (GIL) populations from renal transplant recipients undergoing acute cellular rejection. In most cases these CTL were allorestricted recognizing donor mismatched kidney MHC class I antigens. In contrast, one patient's GIL T cells demonstrated specific lytic activity against HLA-B35 expressed on primary kidney epithelial cell lines (KCL) but not on B-lymphoblastoid cell lines (LCL). Since HLA-B35 was a shared antigen between donor and recipient, these results suggest that CTL within the GIL population are recognizing a tissue-specific minor histocompatibility antigen presented in the context of self-HLA-B35.