Investigation of the effects of exosomes from natural killer (NK) cells on cell cytoxity

The immune system is a complex system that forms a defense mechanism against disease by protecting the body from foreign and harmful microorganisms and substances. The immune system is divided into two main groups: acquired and natural. Natural killer (NK) cells are among the most important and effective cells of the innate immune system. NK cells release cytokines upon stimulation and have the ability to respond very rapidly. NK cells are found in both lymphoid organs and non-lymphoid peripheral tissues such as bone marrow, lung and intestine. The NK-92 cell line is a well-characterized, standardized NK cell line and an ideal source for cell-based immunotherapy. Exosomes are small vesicles released by cells in response to various physiological and pathological conditions. In cancer, exosomes can stimulate antitumor activity. This can stop or slow down the tumor. Proteins and nucleic acids delivered to target cells by NK cell-derived exosomes can effectively alter their biological response. This feature of exosomes makes NKs an even more important factor in their cytotoxicity against cancer cell. For this purpose, exosomes were administered to cancerous and healthy cell groups and their effects on cells were investigated. NK-92 cell line was used in our study and cultured under appropriate conditions. Exosomes were isolated from cultured cells and characterized and validated. Lung cell lines; A549, HTB54 cancer and healthy Beas-2B cell lines were cultured. Isolated NK exosomes were applied to lung cells at different dosages and cell viability was analyzed by WST-1 method. According to the data obtained, NK exosomes decreased cell viability in a dose-dependent manner in experiments with K562 control cell line. In addition, NK exosomes at concentrations determined with K562 cell line decreased cell viability by 30% in HTB-54, Beas2B cell lines, but increased cell viability in A549 cell line. In conclusion, our data showed that NK exosomes could be an innovative therapeutic approach against lung cancer.