Investigation of the size effect of green synthesis goldnanoparticle on lung cancer cell line

Non-small cell lung cancer (NSCLC), which exhibits a heterogeneous and aggressive phenotype, is the most common cause of cancer deaths worldwide. It is known as the most common and deadliest malignancy in all male and female populations. Most cases of lung cancer are diagnosed in the late stages and overall survival rates are low. Surgery is still the main approach used in the treatment of lung cancer; however, many patients die due to relapse and drug treatment failure. Most chemotherapeutic drugs used following surgery cause systemic cytotoxicity and serious side effects in both cancer and healthy cells. Therefore, there is an increasing need for further investigation of new therapeutic targets. It is predicted that green synthesized gold nanoparticles (AuNP) may recently serve as potential therapeutic agents in treating lung cancer in humans, as they can interact with cells at molecular resolution and provide superior biocompatibility. AuNPs, which are metal nanoparticles that are more stable and biocompatible than other nanoparticles, have the potential to be widely used in medicine thanks to their antifungal, antibacterial, antiviral, and anticancer activities. However, Celecoxib, a COX-2 selective inhibitor, plays an important role in the treatment and prevention of cancer. The use of various antineoplastic drugs in combination with COX-2 inhibitors holds promise for cancer control and treatment. It is thought that the combined treatment of AuNP and Celecoxib agent may represent a potential new strategy to inhibit tumor progression by mediating tumor suppressor activities in lung cancer. Studies to be carried out in this context will greatly contribute to preventing and treating lung cancer progression. In this thesis study, AuNPs of different sizes were synthesized by changing the aqueous extract concentration of the root part of the Orchis Spitzelii (Salep) plant, which is known to have an anticancer effect, with green synthesis. Synthesized AuNPs were characterized by UV-Vis, XRD, FT-IR, DLS, Zeta potential, TEM, and FESEM-EDX methods. NCI-H441 human lung cancer and HUVEC cell line were treated with increasing doses of green synthesized AuNPs, Orchis Spitzelii (Salep) plant extract, and Celecoxib agent for 24 hours. The cytotoxic effects of NCI-H441 on human lung cancer and the HUVEC healthy cell line were determined by cell viability testing. With the determined IC50 doses, changes in the gene expressions of CD36, TIMP2, MMP2, PGE2, COX-2, and VEGFR2, which are target genes related to the PPARγ signaling pathway and angiogenesis, invasion, metastasis, and fatty acid metabolism, were examined by qRT-PCR. In addition, the MMP2 protein level change involved in the EMT process was examined by the Western Blot method. As a result of the cell viability test, green synthesized AuNPs showed that their cytotoxicity increased as their size decreased, and as a result of qRT-PCR, they statistically significantly upregulated PPARγ, CD36, and TIMP2 gene expression, which are associated with angiogenesis and EMT process, at a better level than Extract and Celecoxib agent, and MMP2, PGE2. It was concluded that it downregulated the expression of COX-2 and VEGFR2 genes in a statistically significant way. Western Blot study showed statistically significant suppression of MMP2 protein level in parallel with gene expression studies. When all data were evaluated within the scope of the study, it was determined that green synthesized AuNPs exhibited higher biocompatibility against healthy HUVEC cells compared to NCIH441 lung cancer cells, as desired. We showed that green synthesized AuNPs inhibited MMP-2-induced EMT and VEGFR2-induced angiogenesis in lung cancer cells and prevented metastasis. Activation of PPARγ with AuNPs prevents the expression of MMP2, a mesenchymal marker. Together with the low toxicity profile of AuNPs, our data suggest that these nanoparticles may serve as potential therapeutic agents to inhibit metastasis.