Figure 5.

CM-hfMSCs inhibits aldehyde dehydrogenase-positive head and neck squamous cell carcinoma (HNSCC) cell proliferation which corresponded to reduced insulin-like growth factor (IGF)-1R expression levels. (a) The effect of SF-CM-hfMSCs on RPMI2650 HNSCC cells was evaluated by cell counting kit (CCK)-8 assay following 48 hours treatment. Data shown are normalized to SF-CM-Ctrl-treated cells and presented as means ± standard error of the mean (SEM), n = 3. (b) Different clones of HNSCC-CSC population derived from local head and neck cancer patient were subjected to SF-CMs treatment for 48 hours. Huh7-DsRed2 cells were included as positive reference to the activity of the various CMs. The effect was evaluated by CCK-8 assay. Data shown are normalized to respective SF-CM-Ctrl-treated cells and presented as means ± SEM, n = 4. (c) ALD-level of representative clone 56 was assessed following treatment with SF-CM-MRC5 and SF-CM-S33 by flow cytometry analysis. Data shown are means ± SEM, n = 3. (d) Endogenous protein expression of IGF-1R in SF-CMs-treated-HNSCC cells was examined using immunoblot analysis. **P < 0.01; ***P < 0.001.