Osteopontin Mediates Cetuximab Resistance via the MAPK Pathway in NSCLC Cells

Figures & data

Figure 1 Elevated expression of the OPN gene in human NSCLC tissues. (A) Relative expression of OPN mRNA in 125 human NSCLC tissues and 37 normal tissues based on TCGA data. (B) Heatmap of OPN (also known as SPP1) gene expression in clinical NSCLC samples and normal tissues based on Oncomine data. ****P<0.0001. (1. Lung Adenocarcinoma vs Normal Bhattacharjee Lung, Proc Natl Acad Sci USA, 2001;²¹ 2. Lung Adenocarcinoma vs Normal Hou Lung, PLoS One, 2010;²² 3. Lung Adenocarcinoma vs Normal Landi Lung, PLoS One, 2008;²³ 4. Lung Adenocarcinoma vs Normal Selamat Lung, Genome Res, 2012;²⁴ 5. Lung Adenocarcinoma vs Normal Su Lung, BMC Genomics, 2007.²⁵)

Figure 2 Overexpression of OPN induces proliferation, migration, and invasion in NSCLC cells. (A–C) Transfection efficiency of OPN in A549 cells was detected by qPCR and Western blotting. (D) CCK-8 assay was used to detect the proliferation of A549 cells with different transfection conditions. (E, F) The wound healing distance was measured 18 h after the scratch-wound was made for the invasion distance. Scale bars, 500 μm. (G, H) Migration and invasion were detected through transwell assays. Scale bars, 200 μm. *P<0.05, **P<0.01, ***P<0.001.

Figure 3 OPN promotes a malignant phenotype via the MAPK pathway. (A, B) Western blot analysis of p-MEK and p-ERK proteins in different transfected cells. (C, D) Western blot analysis of p-MEK and p-ERK proteins in different groups. (E, F) The wound healing distance was measured in different groups. Scale bars, 500 μm. (G, H) Transwell assay revealed the role of MAPK in the migration and invasion of OPN-transduced cells. Scale bars, 200 μm. *P<0.05, **P<0.01, ***P<0.001.

Figure 4 OPN confers resistance to CTX via the MAPK pathway. (A, B) Colony numbers of different transfected cells were determined at different CTX doses and treatment times. (C, D) Western blot analysis of p-MEK and p-ERK proteins in the overexpression group treated with CTX (10 μg/mL) for 24 h. **P<0.01, ***P<0.001, ****P<0.0001.

Bhattacharjee A, Richards WG, Staunton J, et al. Classification of human lung carcinomas by mRNA expression profiling reveals distinct adenocarcinoma subclasses. Proc Natl Acad Sci U S A. 2001;98(24):13790–13795. doi:10.1073/pnas.19150299811707567

 PubMed Web of Science ®Google Scholar

Hou J, Aerts J, den Hamer B, et al. Gene expression-based classification of non-small cell lung carcinomas and survival prediction. PLoS One. 2010;5(4):e10312. doi:10.1371/journal.pone.001031220421987

 PubMed Web of Science ®Google Scholar

Landi MT, Dracheva T, Rotunno M, et al. Gene expression signature of cigarette smoking and its role in lung adenocarcinoma development and survival. PLoS One. 2008;3(2):e1651. doi:10.1371/journal.pone.000165118297132

 PubMed Web of Science ®Google Scholar

Selamat SA, Chung BS, Girard L, et al. Genome-scale analysis of DNA methylation in lung adenocarcinoma and integration with mRNA expression. Genome Res. 2012;22(7):1197–1211. doi:10.1101/gr.132662.11122613842

 PubMed Web of Science ®Google Scholar

Su LJ, Chang CW, Wu YC, et al. Selection of DDX5 as a novel internal control for Q-RT-PCR from microarray data using a block bootstrap re-sampling scheme. BMC Genomics. 2007;8:140. doi:10.1186/1471-2164-8-14017540040

 PubMed Web of Science ®Google Scholar