CD69 on CD56+ NK cells and response to chemoimmunotherapy in metastatic melanoma

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, TGFβ, 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.

pSTAT3 expression associated with survival and mammographic density of breast cancer patients

BACKGROUND

Constitutive activation of STAT3 have been shown in several tumor types including breast cancer. We investigate STAT3 expresion as possible molecular marker for breast cancer early detection, as well as prognostic factor for determination of tumor agressiveness.

METHODS

In this study we measure p(Y705)STAT3 expression in tumor and adjacent tissue of breast cancer patients by Western blot. For relapse-free survival (RFS) and overall survival (OS) we used Log-Rank test.

RESULTS

We show that average expression of p (Y705) STAT3 in tumor tissue is higher compared to adjacent tissue. Moreover, we found that patients with HER2 positive receptors had significantly higher pSTAT3 expression compared to HER2 negative patients. We showed that patients with high mammographic density had significantly higher tumor expression of pSTAT3 compared to patients with low mammographic density. Also, we show that pSTAT3 expression correlates with longer RFS in the entire group of patients, as well as in the group of ER positive, in lymph node positive and in older group of breast cancer patients (with age over 50). Furthermore, in the entire group of patients, in ER positive, in lymph node positive and in older group of patient, high expression of pSTAT3 showed a better survival than low expression of pSTAT3.

CONCLUSION

Considering that the expression of pSTAT3 is associated with longer RFS and survival, it can be used as prognostic tools for determination of group of breast cancer patients with low-risk.

Health effects of a forest environment on natural killer cells in humans: an observational pilot study

Health effect assessments based on natural killer (NK) cells are an important emerging area of human health. We recruited 90 forest staff members in Xitou, Taiwan and 110 urban staff members in Taipei to investigate the health effects of forest environment exposure on NK cells (CD3⁻/CD56⁺) and activating NK cells (CD3⁻/CD56⁺/CD69⁺) in humans. We also invited 11 middle-aged volunteers in a pilot study to participate in a five-day/four-night forest trip to Xitou forest to investigate the health effects of a forest trip on NK cells and activating NK cells. Results showed that NK cells were higher in the forest group (19.5 ± 9.1%) than in the urban group (16.4 ± 8.4%). In particular, the percentage of NK cells was significantly higher in the forest group than in the urban group among the subgroups of male, a higher body mass index (≥ 25 kg/m²), without hypertension, lower high-sensitivity C-reactive protein, hyperglycemia, without smoking habit, and with tea drinking habit. After the five-day trip in Xitou forest, the percentage of activating NK cells of the invited participants from Taipei increased significantly after the trip to Xitou forest (0.83 ± 0.39% vs. 1.72 ± 0.1%). The percentage of activating NK cells was 1.13 ± 0.43%, which was higher than the baseline value of 0.77 ± 0.38% before the forest trip among the seven subjects who participated in the follow-up study four days after returning to Taipei. This study suggests that exposure to forest environments might enhance the immune response of NK cells and activating NK cells in humans.

Adjuvant Therapy of Uveal Melanoma: Current Status

The survival of patients with uveal melanoma remains poor because of the development of metastatic disease. Adjuvant therapy after treatment of the primary tumor has been tested but has not been shown to prevent the development of metastasis. Several new approaches are being developed. Cytotoxic and immunotherapeutic regimens are being more rationally applied using tumor genetic criteria to better identify patients at risk. Trials in the adjuvant setting of novel immunotherapeutic and targeted agents active in the metastatic setting are being developed, as are approaches to promote cellular differentiation and dormancy. The rarity and biology of uveal melanoma present challenges. Participation in well-designed, scientifically sound clinical trials is critical.

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.

Immune-related biomarkers for diagnosis/prognosis and therapy monitoring of cutaneous melanoma

Skin melanoma, a life-threatening disease, has a recently reported worldwide increase in incidence, despite primary prevention. Skin melanoma statistics emphasize the need for finding markers related to the immune response of the host. The mechanisms that are able to over-power the local immune surveillance comprise molecules that can be valuable markers for diagnosis and prognosis. This article summarizes the immune markers that can monitor the disease stage and evaluate the efficacy of therapeutic interventions. Recent data regarding immunotherapy are presented in the context of tumor escape from immune surveillance and the immune molecules that are both targets and a means of monitoring. Perspectives for developing immune interventions for skin melanoma management and the position of tissue or soluble immune markers as a diagnostic/prognostic panel are evaluated. State-of-the-art technology is emphasized for developing immune molecular signatures for a complex characterization of the patient's immunological status.

Novel aspects of in vitro IL-2 or IFN-α enhanced NK cytotoxicity of healthy individuals based on NKG2D and CD161 NK cell receptor induction

As IL-2 and IFN-α modulate NK cell activity it was of interest to investigate the expression of newly defined NK cell receptors and augmented NK cell activity in healthy individuals after cytokine in vitro treatment. Peripheral blood lymphocytes (PBL) obtained from 31 healthy volunteers treated for 18 h with 200 IU/ml IL-2 and 250 IU/ml IFN-α were evaluated for NK cell cytotoxicity. Expression of NKG2D, CD161, CD158a, CD158b receptors was analyzed on CD3⁻CD16+ NK cells, cytotoxic CD16(bright) and regulatory CD16(dim) subsets by FACS flow. The found induced significant in vitro enhancement of NK cell activity by both cytokines is supported by specific cytokine induction in PBL of pSTAT1 and pSTAT5, determined by Western blotting, as well as induction of IRF-1 transcription. Both cytokines induce significant up-regulation of NKG2D expression while only IFN-α induced significant up-regulation of CD161, with no alteration in KIR expression by either cytokine on CD3⁻CD16+ NK cells. Investigated cytokines did not induce change in NK cell bright and dim subset distribution. Moreover, we find that, not only cytokine receptor induction on the CD3⁻CD16+ NK cells, but also simultaneous increase in their percentage and/or density on CD16(bright) and CD16(dim) subsets, represent good indicators of receptor cytokine-susceptibility. As the role of NK cells has been shown in the loss of tolerance, infection and cancer, the data obtained in this study may be of help in NK cell profiling, by giving referent values of cytokine-induced novel NK cell receptor expression either in evaluation of these diseases or in immunomonitoring during cytokine immunotherapy.

[STAT proteins in cancerogenesis and therapy of malignancies]

Signal transducers and activators of transcription (STAT) proteins are a 7-member family of cytoplasmic transcription factors that participate in signal transduction by cytokines, hormones, and growth factors. STAT proteins control the most important cellular processes, including survival, proliferation and differentiation. A great number of cytokines and other factors in different cell types activate STAT1, STAT3 and STAT5 and in this manner regulate processes such as cellular proliferation, differentiation and survival. STATs such as STAT4 and STAT6 have a more specific effect and are engaged in the differentiation of T helper cell populations. Given the critical roles of STAT proteins it has been established in many studies that STAT3 and STAT5 are oncogenes that can contribute to cellular transformation by increasing proliferation and slowing-down apoptosis. On the other hand, STAT1 is a tumour suppressor gene and its inactivation contributes to malignant transformation. Initially STAT proteins were extensively studied in leukaemias, but later their role in the development of different solid tumours has been also shown. Aside from their role in the development of tumours, STAT1, STAT3 and STAT5 can be considered as molecular markers for early detection of certain types of tumours, as well as prognostic factors in the determination of tumour aggressiveness and predictors of response to various types of therapy. Evidence of the deregulation of STAT signalling pathway can serve as a basis for designing novel targeted molecular therapeutic strategies that carry a great potential in the therapy of solid tumours and leukaemias.