MMP1 Overexpression Promotes Cancer Progression and Associates with Poor Outcome in Head and Neck Carcinoma

Figure 5

MMP1 knockdown inhibits cell proliferation and migration and invasion and triggers apoptosis in HNSCC cells. (a) Endogenous MMP1 protein expression was measured in a panel of HNSCC cell lines as compared to normal oral epithelial (HOK). Representative images of western blot (WB) were shown from 3 independent experiments. (b) Endogenous MMP1 was efficiently silenced by 2 siRNAs (siMMP1-1, siMMP1-2) in Cal27 and Fadu cells. Non-targeting siRNA was utilized as negative control (siNC). Representative images of WB are shown from 3 independent experiments. (c, d) Cell proliferation was remarkably suppressed when endogenous MMP1 was silenced as measured by CCK-8 viability assay. (e) The potentials of colony formation were significantly inhibited in MMP1-depleted cells as compared to control (siNC). (f, g) Increased percentages of cell undergoing apoptosis were evident following MMP1 knockdown as assayed by Annexin V-PI staining. (h, i) The migration (G) and invasion (H) abilities were significantly reduced in siMMP1-transfected cells in wound healing and transwell assays, respectively. (k–m) The protein and mRNA abundance of migration/invasion relevant marker E-cadherin, N-cadherin, Vimentin, and Snail was compared in cells infected siMMP1 or control siNC. (n) Correlation between generic EMT score for HNSCC samples from TCGA dataset and MMP1 expression. Generic EMT score was calculated following the method of single-sample Gene Set Enrichment Analysis (ssGSEA) [24]. Scale bar: 100 μm, Data shown here are mean ± SD from three independent experiments, , , ANOVA analyses.

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