Fig. 4
Radioprotective effects of 3D spheroid-derived SGSCs (SGSCs3D) in a coculture model. a–c Effects of SGSCs3D on IR-induced changes in cell morphology, viability, and proliferation of human parotid epithelial cells (hPECs). Scale bars represent 20 μm. Datasets from three independent experiments (n = 3). d Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assays. e Comparison of percentages of TUNEL-positive apoptotic cells among groups. Data from three independent experiments presented as mean number of apoptotic cells per field ± SEM (n = 3). f Western blotting analysis of proapoptotic and antiapoptotic protein levels. g Protein levels of salivary acinar markers (α-amylase and AQP5), ductal markers (CK7 and CK18), tight junction protein (TJP1), and adherence protein (E-cadherin) determined by western blotting. h Effects of SGSCs2D and SGSCs3D on amylase secretion in hPECs. Amylase activities per wells containing 105 hPECs examined using assay kit. Data from three independent experiments analyzed and presented as mean ± SEM (n = 3). i Intracellular Ca2+ levels measured at baseline and upon stimulation with an agonist. Data presented as mean fluorescence intensity ± SEM. Data from three independent experiments analyzed and presented as mean fluorescent intensity ± SEM (n = 3). Two-way ANOVA, Bonferroni’s post hoc test. *Compared to CON in each group; #compared to IR in each group; $compared to SGSCs2D in each group. ***P < 0.001, ##P < 0.01, ###P < 0.001, $P < 0.05. CON control, IR irradiation, SGSC salivary gland-resident stem cell, SGSCs2D monolayer-cultured SGSCs, [Ca2+] i intracellular calcium