Qianwen Li¹, Rui Meng¹, Gang Wu¹, Sheng Zhang¹, Ke Li²

¹Cancer Center, union  Hospital, Tongji Medical College, Huazhong University of Science and Technology, ²Pharmacy Department,union   Hospital, Tongji Medical College, Huazhong University of Scienceand Technology

Objective:Proteinkinase CK2 (also known ascaseinkinase) is a highlyconserved seine/threonine protein kinase, which isubiquitously expressed inmammalian cells. CK2 has been implicated in multiplephysiological and pathological processranging from cell proliferation andsurvival to carcinogenesis. In our study, we identified the role ofProteinkinase CK2 in the radiosensitivity of non-small cell lung cancer. Method:The protein levels of CK2 α and β subunits in different lung cancercelllines were measured by Western Blotting assays. The protein expression ofthe catalytic subunit-CK2α in different types of lung cancer tissues wasmeasured by immunohistochemistry Clonogenic assays were performed to assess theeffect of a CK2 inhibitor, Quinalizarin, on the radiosensitivity of lungadnocarcinoma A549 and large cell carcinoma H460 cells. Result: Thecatalytic subunit α and regulatory subunit β of CK2 were over expressed indifferent types of lung cancer cells such as A549, H1650, HCC827 and H460 whichwere considered insensitive to X-ray irradiation, whereas a relative lowerexpression of these two subunitswere found in small cell lung cancer cell H446which was sensitive to X-ray irradiation. We tested the protein expression ofthe catalytic subunit CK2α in adenocarcinoma andsquamous carcinoma of lung, andfound that in squamous carcinoma it was mainly expressed in the cytoplasm butnot nucleus, in the common adenocarcinoma it was expressed mainly in thecytoplasm and a small amount in the nucleus and in theacinus typeadenocarcinoma it markerdly gathered in the acini area. We also employedQuinalizarin, which is a specific CK2 inhibitor, to pretreat A549 and H460 lungcancer cells before irradiation and uncovered that cells exposed toQuianlizarin previously had an apparently smaller SF compared to the controlgroup, which reveal thatdown-regulation of CK2 can improve the radisensitivityof lung cancer cells. Conclusion: Inhibition of protein kinase CK2 mightbe apromising way to increase the radiosensitivity of non-small lung cancercells, and further experiments need to be conducted to elucidate its underlyingmechanisms.

Key Words: Protein kinase CK2  Radiosensitivity  Non small cell