Construction of Radiation Surviving/Resistant Lung Cancer Cell Lines with Equidifferent Gradient Dose Irradiation

Abstract

Radiotherapy plays an increasingly crucial role in the treatment of non-small cell lung cancer (NSCLC). Local tumor recurrence and tumor progression caused by intratumoral heterogeneity induced radiotherapy resistance remain the primary causes of radiotherapy failure. However, the lack of a suitable cell line model has hampered the exploration of the dynamic mechanisms of radiation resistance. We established 3 groups of equidifferent gradient dose irradiation surviving/resistant human lung cancer cell lines based on A549, H520, and H460 cells with clinical conventional fractionated radiotherapy (CFRT) (2 Gy × 20 F, 2 Gy × 30 F, and 2 Gy × 40 F). The radiosensitivity of the cells was detected by clone formation assay, EDU cell proliferation assay, neutral comet assay, and γ-H2AX immunofluorescence staining. The radiosensitivity and proliferation viability were increased in a received dose-dependent manner. Compared with parental cells, DNA double-strand breaks (DSBs) in cell lines that received higher-dose irradiation were significantly reduced. We successfully constructed equidifferent gradient dose irradiation surviving/resistant NSCLC cell lines whose radiation surviving and resistant abilities were increased in a received dose-dependent manner. This preclinical cell model could be used to dynamically observe and detect the radiation surviving/resistant biomarkers during radiotherapy stress, elucidate the mechanism of radiation resistance.

Inhibiting p21-activated kinase (PAK7) enhances radiosensitivity in hepatocellular carcinoma

“…During the DSB resulted from various factors, H2AX is phosphorylated into g-H2AX, which, thus, has been taken as an indicator for DNA damage and repair, and its upregulation indicated the exacerbation of DNA damage. 40,41 In our study, we found that the knockout of PAK7 in HCC cells could further increase the IR-induced expression of g-H2AX, which could indirectly implied that PAK7 might reduce the DSB of DNA in HCC cells and accelerate the repair of DNA damage, thereby weakening the sensitivity of cells to radiotherapy. Irradiationassociated DNA damage can lead to G2/M checkpoint activation and consequent G2/M phase arrest, enabling DNA repair to occur prior to cellular entry into mitosis.…”

Effectiveness of hypofractionated and normofractionated radiotherapy in a triple‐negative breast cancer model

“…Most research studies in this field deal either with clinical trials and meta-analysis ( 14 , 26 – 32 ) or with modeling radiobiological effects ( 33 , 34 ). Regarding biological effects of exposure to ionizing radiation, most studies either utilize a single-irradiation dose or focus on fractionated irradiation, applying more fractions over a short time period, to establish surviving/resistant cell lines ( 35 ). Direct radiobiological comparison of fractionation regimens, for instance, in non-small cell lung cancer or glioblastoma cell models reflects the clinical situation with some advantages of hypofractionation for tumor control with no observed increase in radiotoxicity ( 36 , 37 ).…”

Extracellular matrix stiffness mediates radiosensitivity in a 3D nasopharyngeal carcinoma model

“…Two-dimensional (2D) culture-based radioresistance models are still widely employed in radiobiological research today. Radioresistance models are typically formed using conventional fractionated radiotherapy (CFRT), which delivers multiple doses of 2–6 Gy over several rounds, reaching a total dose of 60–80 Gy [ 5 , 6 ]. 2D radioresistance models are monolayer systems that lack the tumor microenvironment and cell–cell contact, which are key factors in radiobiology.…”