Circulating IL-6 is associated with disease progression in BRAFwt metastatic melanoma patients receiving anti-PD-1 therapy.

AIMS: Despite efficacy of anti-PD-1 blockade in treatment of metastatic melanoma (MM), many patients achieve rapid disease progression (DP). Therefore, the aim of this study is to better define biomarkers for DP by analysing levels of circulating cytokines TGF-ß, IFN-γ, IL-6, IL-8 and IL-10 in MM patients prior to anti-PD-1 therapy. METHODS: Cytokine levels were evaluated before therapy with pembrolizumab in peripheral blood of BRAF wild-type (wt) MM patients by ELISA method. RESULTS: In this study, we give pretherapy levels for circulating TGF-ß, IFN-γ, IL-6, IL-8 and IL-10 in BRAFwt MM patients and analyse them according to metastasis stage (M1a+M1 b, M1c, M1d groups), lactate dehydrogenase (LDH) level and occurrence of DP. Increased IL-6 level was found in M1d group (central nervous system metastasis), while LDH+patients (LDH ≥460 IU/L) have increased IL-6 and IL-8 values that correlate with LDH level. Also, IL-6 correlates with C reactive protein values. Furthermore, patients with DP have significantly higher IL-6 level compared with non-DP patients. Conversely, the other analysed cytokines are similar in investigated groups of MM patients. By receiver operating characteristics curve analysis, pretherapy IL-6 level was found to be a biomarker for the occurrence of DP with cut-off value of 3.02 pg/mL. Patients in M1d stage are prevalent in the group with IL-6 ≥3.02 pg/mL that is characterised with reduced progression-free survival and higher pretherapy IL-8 and LDH. CONCLUSION: The evidence in this study implies that baseline IL-6 could be a biomarker of DP and poor prognosis in BRAFwt MM patients treated with pembrolizumab.

Circulating cytokine dynamics as potential biomarker of response to anti-PD-1 immunotherapy in BRAFwt MM patients.

BACKGROUND: The biomarkers of immune checkpoint inhibitors (ICIs) efficacy and safety are still urgently needed. As cytokines are easily detected and monitored in circulation, they could be used as potential predictors of response and immune-related adverse events (irAEs) for ICIs therapy. METHODS: The levels of TGF-ß, IFN-γ, IL-6, IL-8, IL-10 were measured in sera and plasma by ELISA method of 30 healthy controls (HC) and 32 BRAF wild type (wt) MM patients before and after every 12 weeks of Pembrolizumab, PD-1 inhibitor, until one year or disease progression (DP). RESULTS: Higher pretherapy levels of circulating TGF-ß, IFN-γ, IL-6, and IL-10 were shown in MM patients compared to HC. In patients with disease control, TGF-ß and IL-6 first decreased during the therapy, while then they started to successively increase reaching the initial values by the end of the follow up. Furthermore, in this group of patients IFN-γ increased, while IL-8 and IL-10 decreased at final points of the follow up. In patients with DP IL-6 increased at the time of progression, while IL-8 decreased when the best response was achieved. In patients with pseudoprogression IL-6 and IL-10 significantly increased compared to the pretreatment values. Melanoma patients with irAEs had increased baseline values of TGF-ß, IFN-γ, IL-6, and IL-10 compared to HC. However, no significant changes in cytokines levels were found in these patients during therapy. CONCLUSIONS: Inflammatory cytokines monitoring in circulation of BRAFwt MM patients could help in the selection of patients who will have the benefit from Pembrolizumab therapy.

Increased circulating monocyte MDSCs positively correlate with serum Interleukin-10 in metastatic melanoma patients.

Numerous immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and inhibitory cytokines identified in melanoma microenvironment have the important role in immune escape. Therefore, in this study we analyzed monocytic (m)MDSCs in peripheral blood of metastatic melanoma (MM) patients. In peripheral blood of 35 MM patients and 30 healthy controls we analyzed percentage of CD14 + HLA-DR- mMDSCs in monocyte gate and the mean fluorescence intensity of Foxp3 in CD25 + CD4 + regulatory T cells by Flow cytometry. Serum levels of transforming growth factor beta, interferon-gamma, interleukin (IL)-6, IL-8, IL-10 are measured by ELISA assays. In this study MM patients have significantly higher percentage of CD14 + HLA-DR- mMDSCs, as well as increased the baseline mMDSC/PBMC subset (NK, T, B cells, monocytes) ratio. Although there is no significant difference in the percentage of mMDSCs between groups of MM patients with different localization of distant metastasis, patients with elevated serum lactate dehydrogenase (LDH) have statistically significant higher percentage of these cells compared to LDH negative patients. Furthermore, in MM patients there is statistically significant positive correlation between values of IL-10 and the percentage of mMDSCs, only. Therefore, therapeutics that target circulating mMDSCs and IL-10 may have a big importance in the improvement of antitumor immunity in MM patients.

Detection of humoral and cellular immune response to anti-SARS-CoV-2 BNT162b2 vaccine in breastfeeding women and naïve and previously infected individuals.

This study explored humoral and cellular responses to anti-SARS-CoV-2 BNT162b2 mRNA vaccine in breastfeeding women and naïve and seropositive individuals in the first six months after vaccination.Sixty-one volunteers vaccinated with two doses of the BNT162b2 mRNA vaccine were enrolled in the study. In-house developed ELISA was used for the quantification of SARS-CoV-2 RBD-specific antibodies. Cell surface marker expression and intracellular IFN-γ analysis were carried out by flow cytometry. The concentrations of IFN-γ, IL-6 and TNF were determined by ELISA. A significant rise in anti-RBD IgG antibody levels was observed 14 days after the first vaccine dose (p < 0.0001) in serum and milk. The expression of CD28 on CD4+ T cells was significantly higher compared to baseline (p < 0.05). There was a significant increase (p ≤ 0.05) in B cell lymphocyte subset after revaccination, and increased percentage of CD80+ B cells. The expression of IFN-γ in peripheral blood lymphocytes, CD3+ T cells and serum was significantly increased (p < 0.05). No significant difference in immune response was observed between breastfeeding women and other study participants. The anti-SARS-CoV-2 BNT162b2 mRNA vaccine-induced measurable and durable immune response in breastfeeding women and in naïve and previously infected individuals.

Role of Histone Deacetylase 6 and Histone Deacetylase 6 Inhibition in Colorectal Cancer.

Histone deacetylase 6 (HDAC6), by deacetylation of multiple substrates and association with interacting proteins, regulates many physiological processes that are involved in cancer development and invasiveness such as cell proliferation, apoptosis, motility, epithelial to mesenchymal transition, and angiogenesis. Due to its ability to remove misfolded proteins, induce autophagy, and regulate unfolded protein response, HDAC6 plays a protective role in responses to stress and enables tumor cell survival. The scope of this review is to discuss the roles of HDCA6 and its implications for the therapy of colorectal cancer (CRC). As HDAC6 is overexpressed in CRC, correlates with poor disease prognosis, and is not essential for normal mammalian development, it represents a good therapeutic target. Selective inhibition of HDAC6 impairs growth and progression without inducing major adverse events in experimental animals. In CRC, HDAC6 inhibitors have shown the potential to reduce tumor progression and enhance the therapeutic effect of other drugs. As HDAC6 is involved in the regulation of immune responses, HDAC6 inhibitors have shown the potential to improve antitumor immunity by increasing the immunogenicity of tumor cells, augmenting immune cell activity, and alleviating immunosuppression in the tumor microenvironment. Therefore, HDAC6 inhibitors may represent promising candidates to improve the effect of and overcome resistance to immunotherapy.

Increased circulating TGF-ß1 is associated with impairment in NK cell effector functions in metastatic melanoma patients.

Transforming growth factor beta (TGF-ß) plays a complex role in carcinogenesis. In 30 melanoma patients and 20 healthy controls (HC) we analysed functional and phenotypic characteristics of NK cells by Flow cytometry, gene expression of TGF-ß1 in peripheral blood mononuclear cells by qPCR and serum and supernatant level of free TGF-ß1 by ELISA. Melanoma patients had significantly higher serum level of circulatingTGF-ß1 compared to HC, especially those with metastasis into the central nervous system (subclass M1d) and high LDH serum values. Melanoma patients compared to HC had significantly higher level of TGF-ß1 gene in PBMC. TGF-ß1 serum values negatively correlate with NK cell activity analysed by CD107a (degranulation marker), IFN-γ, NKG2D, and NKp46 in patients. Study shows the association of high level of TGF-ß1 with NK cell inhibition in patients represents the main mechanism of tumour immune evasion. Targeting TGF-ß may become an important cancer treatment for improving antitumor immunity.

Cross-Talk Between Tumor Cells Undergoing Epithelial to Mesenchymal Transition and Natural Killer Cells in Tumor Microenvironment in Colorectal Cancer.

Tumor cells undergoing epithelial to mesenchymal transition (EMT) and immune cells in tumor microenvironment (TME) reciprocally influence each other. Immune cells, by supplying TME with bioactive molecules including cytokines, chemokines, enzymes, metabolites, and by physical interactions with tumor cells via their receptors, represent an important factor that affects EMT. Chronical inflammation in TME favorizes tumor growth and invasiveness and stimulates synthesis of EMT promoting transcription factors. Natural killer (NK) cells, owing to their unique ability to exert cytotoxic function independent of major histocompatibility (MHC)-mediated antigen presentation, play a significant role in the control of metastasis in colorectal cancer (CRC). Although, the cross-talk between immune cells and tumor cells in general favors the induction of EMT and inhibition of antitumor immune responses, there are some changes in the immunogenicity of tumor cells during EMT of CRC cells that increase their susceptibility to NK cell cytotoxic lysis. However, suppressive TME downmodulates the expression of activating NK cell receptors, decreases the expression of activating and increases the expression of inhibitory NK cell ligands on tumor cells, and impairs NK cell metabolism that altogether negatively affects the overall NK cell function. Furthermore, process of EMT is often associated with increased expression of programmed cell death ligand (PD-L) and expression of immune checkpoint molecules PD-1, TIGIT, and TIM3 on functionally exhausted NK cells in TME in CRC. In this review we discuss modalities of cross-talk between tumor cells and NK cells, with regard of EMT-driven changes.

Interleukin-4-induced natural killer cell antitumor activity in metastatic melanoma patients.

NK cells are important effectors of innate immunity that mount the first line of defense toward tumor growth. Interleukin-4 (IL-4) has recently been shown to regulate NK cell function, although its role in the regulation of NK cell function in cancer patients has not been clarified. The aim of this study was to investigate the effect of IL-4 on the function and the receptor characteristics of CD16-defined NK cells and their cytotoxic CD16bright and regulatory CD16dim subsets. Peripheral blood lymphocytes obtained from 36 metastatic melanoma (MM) patients treated for 18 h with 10 ng/mL IL-4 were evaluated for NK cell cytotoxicity using the radioactive 51chromium release assay. Expression of the activating receptors NKG2D and CD161, as well as the inhibitory receptors CD158a and CD158b, was analyzed on CD3-CD16+ NK cells and their subsets by flow cytometry. IL-4 induced significant in vitro enhancement of NK cell activity, as well as increased expression of the CD107a degranulation marker, by CD3-CD16dim NK cells. NKG2D expression was also increased on CD3-CD16+ cells by IL-4 with no alteration of the expression of CD161 and inhibitory KIR receptors. Although in vitro treatment with IL-4 increased both the expression of NKG2D and the cytotoxicity of NK cells, it had no detectable effect on the transcription of the TGF-ß gene in NK cells of MM patients. The IL-4-induced NK cell cytotoxicity and increased activating NKG2D receptor expression may indicate an important antitumor effect of IL-4 with a potential application for immunotherapy of MM patients.

Evaluation of cytokine expression and circulating immune cell subsets as potential parameters of acute radiation toxicity in prostate cancer patients.

One of the challenges of radiation oncology in the era of personalized medicine is identification of biomarkers associated with individual radiosensitivity. The aim of research was to evaluate the possible clinical value of the associations between clinical, physical, and biological factors, and risk for development of acute radiotoxicity in patients with prostate cancer. The study involved forty four patients treated with three-dimensional conformal radiotherapy. The concentrations of IL-1ß, IL-2, IL-6, IFN-γ and TGF-ß1 were assessed before radiotherapy, after 5th, 15th and 25th radiotherapy fractions, at the end, and 1 month after the end of radiotherapy. Cytokine gene expression was determined in peripheral blood mononuclear cells. The univariate analysis of circulating cytokine levels during radiotherapy showed that increased serum concentrations of IL-6 were significantly associated with higher grade of acute genitourinary toxicity. The multivariate analysis demonstrated that increased level of IL-6 during the radiotherapy was significantly associated with higher grade of acute genitourinary toxicity across treatment. TGF-ß expression levels significantly decreased during course of radiotherapy. Research indicates that changes in circulating cytokine levels might be important parameter of radiotoxicity in patients with prostate cancer. These findings suggest that future studies based on multi-parameter examination are necessary for prediction of individual radiosensitivity.

The role of cytokines in the regulation of NK cells in the tumor environment.

Natural killer (NK) cells are innate lymphoid cells that are important effectors in the first line of defense toward transformed cells. This is mediated both by direct cytotoxic mechanisms and by production of immunoregulatory cytokines. Recent evidence has shown that NK cells also display memory, similar to the cells of the adaptive immune system. Cytokines are pivotal for the maturation, activation and survival of NK cells. Interleukins (IL)-2, IL-12, IL-15, IL-18, IL-21 and type I interferons positively regulate NK cell function, either independently or in cooperation, whereas other cytokines, such as IL-23 and IL-27, may enhance or suppress NK cell function depending on the context. In the tumor microenvironment, TGFß, IL-10 and IL-6 suppress NK cell activity not only directly, but also indirectly, by affecting immunosuppressive cells and by antagonizing the effect of stimulatory cytokines, thereby dampening the antitumor response of NK cells and promoting subsequent tumor evasion and progression. Increased understanding of the NK cell response to cytokines has provided a better understanding of their impaired function in tumors which may aid in the development of novel immunotherapeutic strategies to enhance NK cell responses in cancer patients.

Evaluation of the Functional Capacity of NK Cells of Melanoma Patients in an In Vitro Model of NK Cell Contact with K562 and FemX Tumor Cell Lines.

NK cells of metastatic melanoma (MM) patients display impaired function, making them incapable to mount an effective antitumor response. In this study, we evaluated immunophenotypic characteristics and functional capacity of CD3-CD16+ NK cells of MM patients in an in vitro model based on NK cell contact with an NK sensitive, K562, and a tumor-specific, melanoma FemX tumor cell line. Although our results indicate similar NK cell antitumor cytotoxic potential of MM patients in contact with both cell lines based on the expression of CD107a degranulation marker, there is a discrepancy in NK cell IFNγ production, as it is not significantly induced by FemX tumor cells, found to be, contrary to K562, HLA class I positive. Furthermore, we show NKG2D receptor downregulation by K562 tumor cell line, only. This may result from the obtained higher gene expression of TGFß and VEGFA growth factors in K562 tumor cells that can negatively regulate NKG2D expression. Additionally, aside from postcontact downmodulation of activating CD16 receptor, there are no significant changes in the expression of CD161, CD158a, and CD158b NK cell receptors. Therefore, the applied in vitro model shows that, compared to the full NK cell functional capacity of MM patients displayed in a tumor-sensitive setting represented by contact with K562 cells, tumor-specific melanoma setting provided by FemX tumor cells leads to reduced NK functional potential. The obtained insight into NK cell capacity may be of use for evaluation of the state of disease and can help in selecting effective immunotherapeutic agents for MM patients.

Attenuated in vitro effects of IFN-α, IL-2 and IL-12 on functional and receptor characteristics of peripheral blood lymphocytes in metastatic melanoma patients.

Considering tumor-induced suppression of lymphocytes the aim of this study was to investigate in vitro effects of IFN-α, IL-2, IL-12 and IL-18 as immunomodulating agents on the functional and receptor characteristics of peripheral blood lymphocytes (PBL) in metastatic melanoma (MM) patients compared to healthy controls (HC). In HC IFN-α, IL-2 and IL-12 enhanced mRNA level of perforin by inducing pSTAT-1 and pSTAT-5 signaling molecules. Additionally, the expression of NKG2D activating receptor and its DAP10 signaling molecule was upregulated by IL-2. Contrary to this, in MM patients only IL-2 by upregulating pSTAT-5 increased perforin-mediated cytotoxicity of lymphocytes. Furthermore, there was significantly negative correlation between the percentage of CD4+CD25bright+CD27+ regulatory T (Treg) cells and NK cell cytotoxicity, as well as the expression of NKG2D receptor on PBL in HC and MM patients. Therefore, the absence of IL-2 effect on the increase of NKG2D/DAP10 level in MM patients could be the consequence of the increased percentage of immunosuppressive CD4+CD25bright+CD27+ cells after this cytokine treatment in patients. However, in MM IL-12 significantly decreases the percentage of these inhibitory cells. Although IL-2 as a single agent has numerous side effects, it remains the important cytokine for PBL activation in melanoma immunotherapy. Additionally, the removal of Treg cells from patient PBL by IL-12 before in vitro stimulation with IL-2, may lead to the generation of more potent cytotoxic lymphocytes against tumor cells. Therefore, lymphocyte based therapy for MM patients should integrate not only the choice of appropriate immunostimulatory cytokine, but also the removal of inhibitory cells from tumor microenvironment.

Beneficial in-vitro effects of interleukin-2, interleukin-12, and their combination on functional and receptor characteristics of natural killer cells in metastatic melanoma patients with normal serum lactate dehydrogenase levels.

Considering tumor-mediated suppression of natural killer (NK) cells, the aim of this study was to investigate the in-vitro effects of interleukin (IL)-2 and IL-12, as immunostimulatory cytokines, on the functional and receptor characteristics of NK cells and their subsets in healthy control (HC) and metastatic melanoma (MM) patients. Peripheral blood mononuclear cells of 27 HC and 35 MM patients were stimulated in vitro with IL-2, IL-12, and their combination for functional and phenotypic analysis. IL-2, IL-12, and primarily their combination, significantly induced NK cell activity, CD107a degranulation marker, and perforin expression in NK cells and their subsets in HC and MM patients. Furthermore, the combination of IL-2 and IL-12 was significantly more efficient than IL-12 alone in the augmentation of NK cell cytotoxicity and CD107a expression. Also, IL-2 and IL-12 reciprocally upregulated each other's receptors, IL-2Rα and IL-12Rß1/ß2, on NK cells and their subsets in MM and HCs. In addition, the priming of NK cells with IL-2 before IL-12 treatment led to an increase in the expression of both IL-12 receptors. In contrast to IL-12, IL-2 increased activating NKG2D and DNAM-1, as well as inhibitory CD158a and CD158b KIRs. In addition, the cytokines investigated exerted a more potent effect on the increase in NK cell activity and the expression of various NK cell receptors in MM patients with normal lactate dehydrogenase (LDH) serum levels. Therefore, serum LDH could represent a predictor of response to cytokine immunotherapy in MM patients. The optimization of combined IL-2/IL-12 therapy is needed to enhance NK cell functions in MM patients stratified by their LDH levels.

Decreased CD161 activating and increased CD158a inhibitory receptor expression on NK cells underlies impaired NK cell cytotoxicity in patients with multiple myeloma.

AIM: As innate immune cells natural killer (NK), NK-like T and CTLγδ are important in antitumour response in multiple myeloma (MM), the aim of this study was to investigate some functional and phenotypical characteristics of these cells in MM. METHODS: 29 patients with MM prior to therapy, in clinical stage I-III and 15 healthy controls (HCs) were investigated. Percent of immune cells in peripheral blood, NK cell activity, expression of activating (CD161) and inhibitory (CD158a, CD158b) NK cell receptors on CD3-CD16+ NK cells were evaluated using 51-chromium-release assay and by flow cytometry. Production of interleukin (IL) 2 and tumour necrosis factor (TNF)α was analysed in supernatants from in vitro activated peripheral blood mononuclear cells. RESULTS: In patients with MM the percent of NK cells and their two subsets did not differ from controls, while NK-like T and CTLγδ cells were significantly decreased. Significant impairment of NK cell cytotoxicity, CD107a expression and interferon γ intracellular level was also shown. There was a significant decrease in CD161 and an increase in CD158a receptor expression on NK cells in these patients. Also IL-2 production was lowest in clinical stage III. However, TNF-α production did not differ between patients and HCs. CONCLUSIONS: Altered expression of CD161 activating and CD158a KIR inhibitory receptor is responsible for impaired antitumour activity of NK cells in MM patients. These new biomarkers may be helpful for patient selection for immunotherapy with cytokines, and novel KIR blocking monoclonal antibodies that enhance NK cell antimyeloma activity and provide clinical benefit.

Decreased expression of pSTAT, IRF-1 and DAP10 signalling molecules in peripheral blood lymphocytes of patients with metastatic melanoma.

AIMS: As numerous signalling molecules regulate effector functions of peripheral blood lymphocytes (PBLs) that have an important anti-tumour activity, the aim of this study was to analyse their level in patients with metastatic melanoma (MM) compared with healthy controls (HCs). METHODS: Peripheral blood mononuclear cells (PBMCs) of 36 MMs and 28 HCs were analysed for the level of perforin, interferon-regulating transcription factor-1 (IRF-1), DAP10 and Src homology 2 domain-containing tyrosine phosphatase-1 by reverse transcriptase PCR, level of phosphorylated signal transducers and activators of transcription (pSTAT)-1, pSTAT-4, pSTAT-5 by western blot and interferon (IFN)-γ production by ELISA. The expression of activating NKG2D and inhibitory killer immunoglobulin-like receptors (KIR), CD158a and CD158b, on PBL, CD3-CD56+ natural killer (NK) cells and CD3+CD8+ cytotoxic T lymphocytes (CTLs), as well as the percentage of CD14+HLA-DR- cells in PBMC were estimated by flow cytometry. RESULTS: Patients with MM, compared with HCs, had significantly lower level of cytotoxic molecule perforin and decreased IFN-γ production, as well as lower level of pSTAT-1, pSTAT-4, pSTAT-5 and IRF-1 signalling molecules in PBMC. Furthermore, MM had decreased expression of activating NKG2D receptor on PBL and NK cells and low level of its DAP10 signalling molecule contrary to no changes in KIR expression on all investigated cells. These results could be associated with increased percentage of immunosuppressive CD14+HLA-DR- myeloid-derived suppressor cells detected in patients with MM. CONCLUSIONS: The altered signalling molecules of PBL could represent biomarkers of impaired cytotoxic and immunoregulatory function of these cells, indicating melanoma-associated immunosuppression that facilitates tumour progression.

Natural killer cell receptors: alterations and therapeutic targeting in malignancies.

Numerous newly identified activating and inhibitory NK cell receptors and their engagement by cognate ligands on target tumor cells regulate NK cell antitumor activity. Alterations in NK cell receptor expression and signaling underlie diminished cytotoxic NK cell function. Cytokines, IFN-α, IL-2, IL-12, IL-15 and IL-18, applied systemically and for ex vivo activation and expansion of NK cells have improved NK cell antitumor activity by increasing the expression of NK cell activating receptors and by inducing cytotoxic effector molecules. Moreover, it has been recognized that classical and novel pharmacological agents upregulate cognate ligands for activating receptors on tumor cells and provide better NK cell antitumor response. Some other immunotherapeutic approaches in cancer in the setting of donor-recipient KIR/HLA mismatch have evolved with the aim to potentiate NK cell activity in allogeneic hematopoietic stem cell transplantation that lead to beneficial graft vs. tumor effect. Therefore, better understanding of NK cell activating and inhibitory receptor biology is needed to assist in developing novel approaches to effectively manipulate NK cells and create effective NK cell-based immunotherapy for treatment of cancer patients.

Favorable in vitro effects of combined IL-12 and IL-18 treatment on NK cell cytotoxicity and CD25 receptor expression in metastatic melanoma patients.

BACKGROUND: As IL-12 and IL-18 have important immunostimulatory role the aim of this study was to investigate their in vitro effects on functional and receptor characteristics of NK cells and their subsets in healthy controls (HC) and metastatic melanoma patients (MM). METHODS: Peripheral blood mononuclear cells (PBMC) of HC and MM were stimulated with culture medium alone, medium supplemented with IL-12 (10 ng/ml), IL-18 (100 ng/ml) and their combination. NK cell activity was determined using radioactive cytotoxicity assay, while perforin, CD107a and pSTAT-4 expression, IFN-γ production and the expression of NKG2D, DNAM-1, CD161, CD158a/b, CD25, IL-12R beta 1/2 receptors on CD3(-)CD56(+) NK cells and their CD3(-)CD56(dim+) and CD3(-)CD56(bright+) subsets were analyzed by flow cytometry. Cytokine induced level of DAP10 in PBMC was analyzed by reverse transcription polymerase chain reaction. RESULTS: IL-12 alone or in combination with IL-18 significantly induced NK cell activity and CD107a degranulation marker expression in MM and HC, while IL-18 alone did not have any effect in patients. The combination of IL-12 and IL-18 significantly increased mean fluorescence intensity (MFI) of IFN-γ in all NK cell subsets in HC and only in the bright subset in MM. MM that belong to M1c group with metastasis in liver and increased LDH serum values had significantly lower increase in NK cell cytotoxicity after combined IL-12 and IL-18 treatment compared to the patients in M1a and M1b categories. These results could be explained by decreased IL-12R expression and lower increase in pSTAT-4 and perforin expression in NK cells of M1c patients after IL-12 and combined IL-12 and IL-18 treatment. IL-18 alone significantly decreased NKG2D receptor expression and level of DAP10 signaling molecule in MM, while combined IL-12 and IL-18 increased the expression of CD25 on all NK cell subsets in HC and MM. Additionally, MM that belong to M1a + M1b group had significantly higher increase in CD25 receptor expression compared to the patients in M1c group. CONCLUSIONS: The novel data obtained in this study support the use of IL-12 and IL-18 in combination for developing new therapeutic strategies for metastatic melanoma especially for patients with better survival rate and prognosis.

Decreased expression of NKG2D, NKp46, DNAM-1 receptors, and intracellular perforin and STAT-1 effector molecules in NK cells and their dim and bright subsets in metastatic melanoma patients.

Although natural killer (NK) cells play an important antitumor role, melanoma cells may affect their effector functions. In this study, we analyzed the expression of various receptors and effector molecules in NK cells and their subsets in metastatic melanoma (MM) patients compared with healthy controls (HCs). In HC and MM patients, we analyzed NK cell activity using a chromium release assay and the expression of CD107a degranulation marker, activating NKG2D, NKp46, DNAM-1, and inhibitory CD158a and CD158b receptors, IL-12R beta 1, IL-12R beta 2, intracellular interferon (IFN)-γ, perforin, and STAT-1 in CD3-CD56+ NK cells, and cytotoxic CD3-CD56 and immunoregulatory CD3-CD56 subsets by flow cytometry. MM patients compared with HC not only had significantly decreased NK cell activity, lower expression of CD107a, and impaired IFN-γ production but also had decreased expression of activating NKG2D, NKp46, and DNAM-1 receptors, which was followed by lower expression of perforin, STAT-1, and both IL-12R subunits in NK cells. In MM patients only, there was a positive correlation between NKG2D expression and degranulation capacity, as well as IFN-γ production in NK cells. Analysis of the expression of various parameters of NK cell effector functions between MM patients with different localization of distant metastases showed that patients in the unfavorable M1c subclass had decreased expression of NKG2D and NKp46 on NK cells compared with patients in the M1a+b group. Downregulated NKG2D, NKp46, and DNAM-1 receptors associated with impaired NK cell effector function are important biomarkers of advanced disease with a poor prognosis in melanoma patients.

Investigation of NK cell function and their modulation in different malignancies.

NK cells have become a subject of investigation not only in the field of tumor immunology and infectious diseases, but also within all aspects of immunology, such as transplantation, autoimmunity, and hypersensitivity. Our early studies aside from investigating NK cell activity in experimental animals and humans included studies of perforin expression and modulation in this lymphocyte subset. As NK cell activity is modified by their environment, we showed clinical stage-dependent impairment of their activity and in vitro effect of different sera, Th1 cytokines, and their combination in breast cancer, Hodgkin's disease, and non-Hodgkin's lymphoma patients, especially with respect to metabolic and cell membrane changes of peripheral blood lymphocytes evaluated by spontaneous release of the enzyme lactate dehydrogenase (LDH) that led to the correction of the LDH enzyme release assay for natural cytotoxicity. By long-term immuno-monitoring of patients with malignancies, we also showed the kinetics of NK cell modulation during chemo-immunotherapy. In our more recent studies, we give data of NK function and novel families of NK cell receptor expression in healthy individuals that may be of help in NK cell profiling, by giving referent values of basic and cytokine-induced expression of some NK cell receptors either in evaluation of disease or in immuno-monitoring during cytokine therapy of patients with malignancies. Moreover, we give novel aspects of modulation of NK cell activity by cytokines approved for immunotherapy, IFN and IL-2, in melanoma and other malignancies with respect to alterations in new activating (NKG2D and CD161) and inhibitory (CD158a and CD158b) receptor characteristics and signaling molecules in CD16- and CD56-defined NK cells and their small immunoregulatory and large cytotoxic subsets in peripheral blood and lymph nodes, as NK cell-mediated killing of tumor cells depends on the balance between stimulatory and inhibitory signaling.

The stage dependent changes in NK cell activity and the expression of activating and inhibitory NK cell receptors in melanoma patients.

BACKGROUND: As NK cell antitumor activity is regulated by the balance between numerous activating and inhibitory receptors the aim of this study was to analyze the changes in these receptors expression as well as the differences in their association with NK cell activity in melanoma patients in different clinical stages. MATERIALS AND METHODS: Forty-three melanoma patients in the three different clinical stages and 17 healthy controls were analyzed for NK cell activity by the standard (51)Cr radioactive assay, as well as for the percentage and absolute number of CD3-CD56+ NK cells and their subsets and the expression of degranulation marker CD107a, activating NKG2D and CD161, and inhibitory KIR, CD158a, and CD158b receptors on CD3-CD56+ NK cells by flow cytometry. IFN-γ and TNF-α PBL production were evaluated by enzyme-linked immunosorbent assay (ELISA). RESULTS: We show that contrary to nonmetastatic, metastatic melanoma patients have significantly impaired NK cell activity, lower CD107a expression, as well as decreased production of IFN-γ and TNF-α. Furthermore, these melanoma patients have a significant decrease in the expression of activating NKG2D receptor, which positively correlates with NK cytotoxicity, and a significant increase in the expression of inhibitory CD158b on CD3-CD56+ NK cells compared with healthy controls. CONCLUSIONS: In this study, we show that metastatic melanoma patients have significant changes in NK cell activity and the expression of activating as well as inhibitory NK cell receptors. These results indicate that only in this patient group, the blocking of inhibitory or enhancing of activating NK cell receptor expression may promote NK cell-mediated cytolysis.