IntroductionC‐kit/SCF signaling plays a key role in regulating NK cell homeostasis, maturation, proliferation, and cytotoxicity. C‐kit‐deficiency in NK cells results in significant reduction of their number, suggesting an imperative role for c‐kit signaling in NK cell biology. We have recently showed that human NK cells express not only c‐kit‐receptor, but also both membrane‐bound and soluble forms of c‐kit ligand—Stem cell factor. The goal of this study was to characterize the c‐kit/SCF autocrine loop in peripheral blood NK cells obtained from patients with cancer.MethodsUsing Smart Flare and qRT‐PCR, we have characterized expression of c‐kit and two forms of SCF in patients’ NK cells and correlated these results with the expression of c‐myc and STAT3.ResultsOur results demonstrated that the expression of proto‐oncogenes c‐myc and c‐kit was significantly decreased in NK cells from all cancer patients. Expression of membrane‐bound SCF in NK cells correlated with the presence of remote metastases.ConclusionsWe suggest that the abnormal signaling and expression of c‐kit/SCF, c‐myc, and STAT3 in NK cells is responsible for the defect in their cytolytic activity in cancer and these defects at the gene expression level may be the cause rather than the result of tumor progression.

Natural killer (NK) cells have received a lot of attention in recent years for the roles they play in immunity and particularly in antitumor immune responses. Although defects in NK cell functions are recognized as important mechanisms for immune evasion of malignant cells, molecular pathways regulating NK cell dysfunction and exhaustion in cancer are largely unknown. Here we tested whether the c-myc proto-oncogene, known to promote cell proliferation, growth, differentiation, and apoptosis by regulating the expression of numerous target genes, may be involved in the mechanism of NK cell abnormalities in patients with lung and gastric cancer. Analysis of c-myc mRNA and protein expression in peripheral blood NK cells, mitogen-activated protein kinase (MAPK) activity, cell cycle, and cell longevity revealed a significantly decreased expression of c-myc mRNA and protein and mitotic arrest of NK cells in different phases of cell cycle. In addition, a significant decrease of NK cell death was also detected. These data allow the suggestion that defects of NK cell-mediated tumor surveillance may be associated with disturbed c-myc expression in NK cells in cancer patients. A better understanding of the mechanisms of NK cell dysfunction in cancer will help in the NK cell-mediated therapeutic eradication of primary and metastatic cancer cells and prolong patient survival.

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Collectively, the current study shows phenotypic alterations in suppressive receptors of Treg subsets, suggesting that breast cancer patients have increased activity of N nTregs, EM nTregs and Tr1 cells; and EM nTregs and CD25 Tr1 cells represent prospective markers for assessing disease prognosis.

We studied the effect of delta sleep-inducing peptide on GABA receptors of hippocampal and cerebellar neurons in rats. It was shown that delta sleep-inducing peptide considerably and dose-dependently potentiates GABA-activated currents in these neurons and blocks NMDA-activated potentiation in cortical and hippocampal neurons. The peptide modulates activity of presynaptic NMDA receptors, which is seen from changes in (45)Ca(2+) uptake into synaptosomes of the brain cortex after uptake stimulation with glutamate and NMDA.