Mirjana Urosevic

Human Leukocyte Antigen G Up-Regulation in Lung Cancer Associates with High-Grade Histology, Human Leukocyte Antigen Class I Loss and Interleukin-10 Production

Immune evasion in lung cancer results from both structural and functional alterations of human leukocyte antigen (HLA) class I molecules and the local release of immunosuppressive cytokines. Recent data suggest that HLA-G, a nonclassical class Ib molecule, is involved in immune evasion by tumor cells. We sought to determine whether HLA-G could contribute to immunescape in lung cancer. All of 19 tumor specimens examined demonstrated detectable membrane-bound (HLA-G1), as well as soluble (HLA-G5) isoform transcription. Nine of 34 (26%) tumors were positive by immunohistochemistry using monoclonal antibody (mAb) 4H84, recognizing all denatured HLA-G isoforms, of which six were positive using mAb 16G1, recognizing soluble HLA-G. HLA-G immunoreactivity correlated with high-grade histology, with HLA-G being preferentially expressed on large-cell carcinomas. In these patients, loss of classical HLA class I molecules was observed to associate with HLA-G protein up-regulation. Moreover, we found interleukin-10 expressed in 15 of 34 (44%) tumors, and in most of the HLA-G-positive cases (7 of 9), suggesting up-modulation of HLA-G by interleukin-10. It is conceivable that HLA-G expression in lung cancer might be one of the ways how the tumor down-regulates host immune response, in addition to interleukin-10 production and HLA class I loss.

Induction of Genes Mediating Interferon-dependent Extracellular Trap Formation during Neutrophil Differentiation

Interferons (IFNs) are cytokines that possess potent anti-viral and immunoregulatory activities. In contrast, their potential role(s) in anti-bacterial defense and neutrophil activation mechanisms is less well explored. By comparing gene expression patterns between immature and mature human neutrophils, we obtained evidence that intracellular proteases and other anti-bacterial proteins are produced at earlier stages of maturation, whereas the genes for receptors and signaling molecules required for the release of these effector molecules are preferentially induced during terminal differentiation. For instance, mature neutrophils strongly expressed genes that increase their responses to type I and type II IFNs. Interestingly, granulocyte/macrophage colony-stimulating factor was identified as a repressor of IFN signaling components and consequently of IFN-responsive genes. Both IFN-α and IFN-γ induced strong tyrosine phosphorylation of STAT1 in mature but not in immature neutrophils. Functional in vitro studies suggested that IFNs act as priming factors on mature neutrophils, allowing the formation of extracellular traps upon subsequent stimulation with complement factor 5a (C5a). In contrast, both IFN-α and IFN-γ had only little capacity to prime immature cells in this system. Moreover, both IFNs did not have significant anti-proliferative effects on immature neutrophils. These data contribute to our understanding regarding changes of gene expression during neutrophil differentiation and IFN-mediated anti-bacterial defense mechanisms.

HLA-G and IL-10 expression in human cancer—different stories with the same message

Immune evasion in cancer may result from structural and functional alterations of human leukocyte antigen (HLA) class I molecules and/or local release of immunosuppressive cytokines, such as interleukin (IL)-10. In lung cancer, both of these mechanisms seem to often take place, resulting in the impaired tumor recognition and the progression of the disease. In primary cutaneous lymphomas on the other side, the shift towards immunosuppressive T helper (Th)2 cytokine profile and the secretion of IL-10 appears to occur more frequently than the loss of HLA class I molecules. In addition to down-regulation of HLA class I expression, IL-IO appears to be one of the factors responsible for the up-regulation of HLA-G, another molecule involved in the immunescape. It is possible that the expression of HLA-G itself may account for induction of Th2-skewing state and the production of IL-10, thence establishing a vicious circle of immune abrogation in cancer. This article reviews the current literature on this topic and provides new insights into the role of HLA-G and IL-10 in cancer.

Superficial radiotherapy for patients with basal cell carcinoma: Recurrence rates, histologic subtypes, and expression of p53 and Bcl-2

The histologic subtype of a basal cell carcinoma (BCC) may be an important factor for the success of a certain treatment modality. In the current article, the authors report recurrence rates among patients with BCC after superficial radiotherapy as well as Bcl‐2 and p53 expression levels stratified by BCC subtype.

An Exploratory Study of Systemic Administration of the Toll-like Receptor-7 Agonist 852A in Patients with Refractory Metastatic Melanoma

Purpose: A topical Toll-like receptor 7 (TLR7) agonist induces regression of cutaneous melanocytic neoplasms. We explored antitumor activity of a systemically administered TLR7 agonist, 852A, in patients with metastatic melanoma. Experimental Design: We undertook a phase II, multicenter, open-label study in patients with chemotherapy-refractory metastatic melanoma. Patients received i.v. 852A, starting at 0.6 mg/m2 and increasing to 0.9 mg/m2 based on tolerance, thrice per week for 12 weeks. Clinical response was determined by Response Evaluation Criteria in Solid Tumors. Immune effects of 852A were monitored by measuring serum type I IFN and IP-10 together with assessment of immune cell markers in peripheral blood. Results: Twenty-one patients were enrolled. Thirteen patients completed the initial 12-week treatment cycle, with two discontinuing for adverse events considered to be possibly related to study drug. Four (19%) patients had disease stabilization for >100 days. One patient had a partial remission after two treatment cycles, but progressed during the third. Dose-limiting toxicity was observed in two patients. Serum type I IFN and IP-10 increased in most patients on 852A administration. Serum type I IFN increases were greater after dosing with 852A 0.9 mg/m2 than after 0.6 mg/m2 (P = 0.009). The maximal increase in IP-10 compared with baseline correlated with the maximal increase in type I IFN (P = 0.003). In the eight patients with immune cell marker data, CD86 expression on monocytes increased significantly post-first dose (P = 0.007). Conclusion: Intravenous 852A was well tolerated and induced systemic immune activation that eventually resulted in prolonged disease stabilization in some patients with stage IV metastatic melanoma who had failed chemotherapy.

Imiquimod Treatment Induces Expression of Opioid Growth Factor Receptor: A Novel Tumor Antigen Induced by Interferon-α?

Purpose: Imiquimod represents a synthetic local immune response modifier that has demonstrated efficacy in clearing basal cell carcinoma. Via interaction with Toll-like receptor 7 on immune cells, imiquimod induces local production of cytokines, such as interferon (IFN)-α. Experimental Design: To more closely define and elucidate mechanisms leading to basal cell carcinoma clearance in vivo, we examined gene expression profiles of skin basal cell carcinoma before and after treatment with 5% imiquimod cream (Aldara) by using high-density oligonucleotide arrays. Results: We show that imiquimod predominantly induces genes involved in different aspects of immune response. In addition to effects on immunity, imiquimod treatment modulates the expression of genes involved in the control of apoptosis and oncogenesis. Array data indicated that imiquimod treatment induces expression of opioid growth factor receptor, a molecule recently reported to be a target for antitumor antibody responses. Immunohistochemistry revealed in vivo up-regulation of opioid growth factor receptor protein on tumor and on infiltrating cells after treatment. By using basal cell carcinoma cell lines treated with IFN-α or imiquimod, we show that opioid growth factor receptor up-regulation is IFN-α-mediated, rather then directly imiquimod-mediated. By using tissue microarray containing 52 basal cell carcinomas, we demonstrate opioid growth factor receptor expression in almost half of the cases. Expression of opioid growth factor receptor correlated with a longer recurrence-free period in basal cell carcinoma that recurred after radiotherapy (Kaplan-Meier analysis, P = 0.041). Conclusions: In addition to its immunomodulatory and antiproliferative activity, opioid growth factor receptor seems to have a prognostic significance in basal cell carcinoma patients. Our data add to the growing list of basal cell carcinoma-associated tumor antigens.

Immunotherapy for nonmelanoma skin cancer: Does it have a future?

Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin are the most common malignancies in the white human population, accounting for greater than 95% of nonmelanoma skin cancers (NMSCs). Current data show an increasing incidence of NMSC in recent decades. Although the mortality is low, this cancer group is associated with substantial morbidity. Multiple treatment modalities are available for NMSC, with surgery being a “cornerstone” of current therapy approaches. However, in patients with multiple lesions or in cases of tumors on critical locations, disfigurement and the disease recurrence may represent a serious problem associated with the surgical treatment. The purpose of this study was to review and analyze whether NMSC could represent a target for immune therapy, evaluating the aspects of the availability of tumor antigens and the existence of tumor specific immune response, including a summary of the major clinical studies dealing with immunotherapy for NMSC.

Imiquimod Induces Complete Clearance of a PUVA-Resistant Plaque in Mycosis fungoides

Imiquimod is a topical immune response modifier that binds to Toll-like receptors 7 and 8 and induces α-interferon. We locally applied imiquimod 5% cream (Aldara®) daily for 2 weeks on a PUVA- and retinoid-resistant plaque on the face of a patient with mycosis fungoides. The diagnosis was based on clinical appearance, histology and molecular studies. Most of the disease manifestations showed a clear remission during PUVA therapy combined with low-dose retinoids. However, the plaque on the face was PUVA resistant. Local imiquimod treatment resulted in the complete clearance of the plaque. The patient has now been in complete remission for 12 months.

Pathogenesis of cutaneous lymphomas.

Cutaneous lymphomas are a heterogeneous group of lymphoproliferative disorders derived from T cells, B cells and, in rare cases, natural killer cells. The precise mechanisms of the lymphomagenesis are still obscure. However, there are various factors involved. These factors include environmental, especially infectious factors, translocations, mutations and genetic instability. The special microenvironment in the skin is responsible for the peculiar behavior of these neoplasms by providing various key factors, such as adhesion molecules and cytokines. Newly identified molecular disturbances in cutaneous lymphomas might be targeted by specific molecular or immunologic interventions in the future.

Green tea extract reduces induction of p53 and apoptosis in UVB-irradiated human skin independent of transcriptional controls

Abstract:  Ultraviolet (UV) irradiation plays a pivotal role in human skin carcinongenesis. Preclinically, systemically and topically applied green tea extract (GTE) has shown reduction of UV‐induced (i) erythema, (ii) DNA damage, (iii) formation of radical oxygen species and (iv) downregulation of numerous factors related to apoptosis, inflammation, differentiation and carcinogenesis. In humans, topical GTE has so far only been tested in limited studies, with usually very high GTE concentrations and over short periods of time. Both chemical stability of GTE and staining properties of highly concentrated green tea polyphenols limit the usability of highly concentrated green tea extracts in cosmetic products. The present study tested the utility of stabilized low‐dose GTE as photochemopreventive agents under everyday conditions. We irradiated with up to 100 mJ/cm2 of UVB light skin patches which were pretreated with either OM24®‐containing lotion or a placebo lotion. Biopsies were taken from both irradiated and un‐irradiated skin for both immunohistochemistry and DNA microarray analysis. We found that while OM24® treatment did not significantly affect UV‐induced erythema and thymidine dimer formation, OM24® treatment significantly reduced UV‐induced p53 expression in keratinocytes. We also found that OM24® treatment significantly reduced the number of apoptotic keratinocytes (sunburn cells and TUNEL‐positive cells). Carefully controlled DNA microarray analyses showed that OM24® treatment does not induce off‐target changes in gene expression, reducing the likelihood of unwanted side‐effects. Topical GTE (OM24®) reduces UVB‐mediated epithelial damage already at low, cosmetically usable concentrations, without tachyphylaxis over 5 weeks, suggesting GTE as suitable everyday photochemopreventive agents.