en زیست شناسی ملکولی Molecular Biology مقالات اصلی Original Article <em><strong>Background: </strong></em>The clinical effect of photodynamic therapy (PDT) may be correlated with the degree of&nbsp;dysplasia of cancer tissues. The aim of this study was to compare the effects of cisplatin, silver nanoparticles&nbsp;(AgNps), and photodynamic therapy (PDT) using methylene blue (MB) photosensitizer on Head and Neck&nbsp;squamous cell carcinoma - cell line (HNSCC), Hep-2, through genes expression.<br> <br> <strong><em>Methods:</em></strong> Hep-2 cells were divided into four groups: group I as control and without any treatment, group II&nbsp;and III were treated by cisplatin and AgNps, respectively, and group IV were incubated with MB for four&nbsp;minutes followed by PDT using laser irradiation at 650 nm for 8 minutes. The resulting toxicity was assessed&nbsp;in cell lines using MTT cytotoxicity assay. Further, apoptosis and the response to treatment was examined<br> via RT-qPCR.<br> <br> <em><strong>Results:</strong></em> MB-PDT inhibited the proliferation of Hep-2 cells. Following PDT, compared with AgNps cells&nbsp;and via MTT assay, a highly significant decrease was observed in cell proliferation in Cancer cells treated&nbsp;with AgNps and MB- PDT groups compared to cancer group cells and cancer cells treated with Cisplatin<br> (p value< 0.001). Mechanistically, both the mRNA and protein expression levels of Bcl-2, Caspase-3,&nbsp;Cyclin-D, HIF-1, IL-8, MAPK-38, and ROS were found to be down regulated in Hep-2 cell line after MBPDT.<br> <br> <strong><em>Conclusions:</em></strong> MB-PDT effectively killed Hep-2 cells in vitro, however, under the same conditions, the&nbsp;susceptibilities of the cell line to cisplatin, AgNps, and MB-PDT were different. Further studies are&nbsp;necessary to confirm whether this difference is present in clinical oral cancer lesions. Head and Neck squamous cell carcinoma (HNSCC) silver nanoparticles (AgNps) photodynamic therapy (PDT), Methylene Blue (MB), Photosensitizer (PS). 224 237 http://rbmb.net/browse.php?a_code=A-10-580-2&slc_lang=en&sid=1 Marwa Abdelgwad 100319475328460013033 100319475328460013033 No Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Giza, Egypt. Dina Sabry 100319475328460013034 100319475328460013034 No Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Giza, Egypt & Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Badr University in Cairo, Badr City 11829, Egypt. Latifa Mohamed Abdelgawad atifa.mohamed@cu.edu.eg. 100319475328460013035 100319475328460013035 Yes Medical applications of lasers Department, National Institute of Laser Enhanced Sciences (NILES), Cairo University, Giza, Egypt. Doaa Mohamed Elroby Ali 100319475328460013036 100319475328460013036 No Biochemistry Department, Faculty of Pharmacy, Deraya University, Minia, Egypt & Biochemistry and molecular biology Department, Faculty of pharmacy, Suhag university, Suhag, Egypt.