Aml Hastalarında Nkp30 Ve B7-H6, Gal-3, Bag6 Ekspresyon Düzeyleri İle Nk Hücre Sitotoksitesi Arasındaki İlişki

Abstract

ABSTRACT Aydın,B. The relationship between NKp30 and B7-H6, Gal-3, BAG6 expression levels and NK cell cytotoxicity in AML patients. Master of Science Thesis of Hacettepe University Graduate School of Health Sciences Department of Tumor Biology and Immunology, Ankara, 2020. Acute myeloid leukemia (AML) is a heterogeneous group of disease which characterized by the abnormal proliferation of hematopoietic progenitor cells at differentiation stages. Although recent advances in treatment of AML, the prognosis is still poor. In hematologic malignancies such as acute myeloid leukemia, the receptor-ligand relationships affect activity and cytotoxicity of NK cells that is very important in terms of killing leukemia cells by NK cells. Several studies have shown that NK cell activity and cytotoxicity are very low in AML patients, and the causes of this situation have not been fully understood. In this thesis, our aim is to determine how NK cells, NKp30 receptors and their soluble ligands and cytotoxicity genes of NK cells are affected by AML disease and AML treatment. 9 AML patients and 7 healthy individuals were enrolled in this study. Evaluation of NK cell numbers was shown that the percentage of NK cells tend to decrease in the pretreatment AML group (p>0.05). When NK subgroups were examined, it was found that amount of CD56bright NK cells were lower than the control group but higher than the post-treatment group (p>0.05). In CD16dim/neg NK cell subtype, it was found that there was a decrease in the pre-treatment group compared to the control group and an increase in the post-treatment group (p>0.05). NKp30 expressing NK cells were found to be higher compared to the control group but the percentage of these cells were lower in the post-treatment group than the pre-treatment group (p>0.05). Differentiation in the serum concentrations of B7-H6, BAG-6 and GAL-3 ligands, which are known as soluble form inhibitors of the NKp30 receptors, were also evaluated in this study. It has been found that the serum concentrations of these ligands in the pre-treatment group tends to decrease as compared to the control group, but there were no alterations of serum concentrations in post-treatment group (p>0.05). Transcriptome analysis (NGS mRNAseq) was performed to investigate how NK cell gene expression levels change in AML patients as compared to control group. Expression of NKp30 mRNA (log 9.86), which is higher in the pre-treatment group than the control group, was remarkable. PSMA1, CD27-AS1, some miRNAs and NK cell associated KIR2DL3, IFNAR2, BID, BRAF gene expressions were also found to be increased in patients. Fas, CD244 and PIK3CD gene expression levels decreased in the patient group. NK cell-related receptor genes which are expected to be expressed were also examined separately. Depending on the RNA isolation method used, some of the genes expected to be expressed could not be identified in both groups. In pathway analysis, increase in some genes associated with PI3K pathway have been demonstrated. According to all these results, when compared with healthy donors, differences in certain molecules and genes that are important for the function of NK cells have been observed in AML patients. Detecting these differences, knowing the causes, and solving the mechanisms will be important for the treatment and prognosis of AML.

Keywords: Natural killer (NK) cells, acute myeloid leukemia (AML) NKp30, cytotoxicity, B7-H6, BAG-6, GAL-3, transcriptome.

This study supported by Hacettepe University Scientific Research Unit.(Project No: 17025)