Browsing by Author "Babović, Nada (6602584307)"

In metastatic melanoma (MM) immunomodulating agents, such as interleukin-2 (IL-2) and interferon-α (IFN-α), have shown therapeutic benefit as they enhance antitumor immune response. Considering tumor-induced suppression of natural killer (NK) cell activity, it is of interest to study the affect of these cytokines on the functional and receptor characteristics of CD16-defined NK cells and their dim and bright subsets. Peripheral blood lymphocytes of MM patients in clinical stage IV were treated in vitro for 18h with IFN-α (250U/ml) and rhIL-2 (200U/ml) at 37°C. Both the cytokines induced significant in-vitro enhancement of NK cell activity. NKG2D receptor was induced by IL-2, whereas both the NKG2D and CD161 receptor expression was induced by IFN-α on NK cells and CD16bright NK cell subset. However, only IL-2 mediated induction of NKG2D on CD3-CD16 NK cells correlates with enhanced NK cytotoxicity by this cytokine, whereas, on the cytotoxic CD16 subset NKG2D induction by both cytokines correlates with their induction of NK cell activity. In contrast, the observed induction of these receptors on the regulatory CD16 subset shows no correlation with the obtained augmentation of cytotoxicity. We found substantial specific inducibility of pSTAT1 and pSTAT5, as well as induction of interferon-regulatory transcription factor-1 transcription by investigated cytokines in peripheral blood lymphocytes of MM patients. As NK cell-mediated killing of tumor cells depends on the balance between stimulatory and inhibitory signaling, induction of activating NKG2D receptor by IL-2 and IFN-α, especially in CD16 NK cell subset, gives insight to novel aspects of NK cell activation by these cytokines that are applied in immunotherapy. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

In metastatic melanoma (MM) immunomodulating agents, such as interleukin-2 (IL-2) and interferon-α (IFN-α), have shown therapeutic benefit as they enhance antitumor immune response. Considering tumor-induced suppression of natural killer (NK) cell activity, it is of interest to study the affect of these cytokines on the functional and receptor characteristics of CD16-defined NK cells and their dim and bright subsets. Peripheral blood lymphocytes of MM patients in clinical stage IV were treated in vitro for 18h with IFN-α (250U/ml) and rhIL-2 (200U/ml) at 37°C. Both the cytokines induced significant in-vitro enhancement of NK cell activity. NKG2D receptor was induced by IL-2, whereas both the NKG2D and CD161 receptor expression was induced by IFN-α on NK cells and CD16bright NK cell subset. However, only IL-2 mediated induction of NKG2D on CD3-CD16 NK cells correlates with enhanced NK cytotoxicity by this cytokine, whereas, on the cytotoxic CD16 subset NKG2D induction by both cytokines correlates with their induction of NK cell activity. In contrast, the observed induction of these receptors on the regulatory CD16 subset shows no correlation with the obtained augmentation of cytotoxicity. We found substantial specific inducibility of pSTAT1 and pSTAT5, as well as induction of interferon-regulatory transcription factor-1 transcription by investigated cytokines in peripheral blood lymphocytes of MM patients. As NK cell-mediated killing of tumor cells depends on the balance between stimulatory and inhibitory signaling, induction of activating NKG2D receptor by IL-2 and IFN-α, especially in CD16 NK cell subset, gives insight to novel aspects of NK cell activation by these cytokines that are applied in immunotherapy. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Natural killer (NK) cells play a role in the innate and adaptive antitumor immune responses. The activity of NK cells is regulated by functionally opposing, activating and inhibitory receptors whose balance ultimately determines whether target cells will be susceptible to NK cell mediated lysis. As melanoma is an immunogenic tumor, the effect of immunomodulating agents is consistently investigated. In this study in 79 metastatic melanoma (MM) patients and 52 controls NK activity, expression of activating NKG2D and CD161 receptors and KIR receptors, CD158a and CD158b, on freshly isolated PBL and NK cells were evaluated. Native NK cell activity of melanoma patients in clinical stage I-III and MM patients was determined against NK sensitive K562, NK resistant Daudi, human melanoma FemX, HeLa and HL 60 target tumor cell lines. In addition, predictive pretherapy immunomodulating effect after 18 h in vitro treatments of PBL of MM patients with rh IL-2, IFN-α (IFN), 13-cis retinoic acid (RA) and combination IFN-α and RA was evaluated with respect to NK cell lyses against K562 and FemX cell lines. In this study we show for the first time that low expression of CD161 and activating NKG2D receptors, without increased expression of KIR receptors CD158a and CD158b, as well as a decrease in the cytotoxic, CD16bright NK cell subset, is associated with a significant impairment in NK cell activity in MM patients. Furthermore, the predictive pretherapy finding that IL-2, IFN, IFN and RA, unlike RA alone, can enhance NK cell activity of MM patients against FemX melanoma tumor cell line can be of help in the design and development of therapeutic regimens, considering that it has recently been shown that low-dose combination of different immunomodulators represents the most promising approach in the therapy of MM. © 2007 Springer Science + Business Media B.V.

Natural killer (NK) cells play a role in the innate and adaptive antitumor immune responses. The activity of NK cells is regulated by functionally opposing, activating and inhibitory receptors whose balance ultimately determines whether target cells will be susceptible to NK cell mediated lysis. As melanoma is an immunogenic tumor, the effect of immunomodulating agents is consistently investigated. In this study in 79 metastatic melanoma (MM) patients and 52 controls NK activity, expression of activating NKG2D and CD161 receptors and KIR receptors, CD158a and CD158b, on freshly isolated PBL and NK cells were evaluated. Native NK cell activity of melanoma patients in clinical stage I-III and MM patients was determined against NK sensitive K562, NK resistant Daudi, human melanoma FemX, HeLa and HL 60 target tumor cell lines. In addition, predictive pretherapy immunomodulating effect after 18 h in vitro treatments of PBL of MM patients with rh IL-2, IFN-α (IFN), 13-cis retinoic acid (RA) and combination IFN-α and RA was evaluated with respect to NK cell lyses against K562 and FemX cell lines. In this study we show for the first time that low expression of CD161 and activating NKG2D receptors, without increased expression of KIR receptors CD158a and CD158b, as well as a decrease in the cytotoxic, CD16bright NK cell subset, is associated with a significant impairment in NK cell activity in MM patients. Furthermore, the predictive pretherapy finding that IL-2, IFN, IFN and RA, unlike RA alone, can enhance NK cell activity of MM patients against FemX melanoma tumor cell line can be of help in the design and development of therapeutic regimens, considering that it has recently been shown that low-dose combination of different immunomodulators represents the most promising approach in the therapy of MM. © 2007 Springer Science + Business Media B.V.

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 51Cr 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. © 2011 Elsevier Inc. All rights reserved.