Drug exposure in a metastatic human lung adenocarcinoma cell line gives rise to cells with differing adhesion, proliferation, and gene expression: Implications for cancer chemotherapy

Abstract

The Am1010 cell line was previously established from a metastatic deposit in an arm muscle from a patient with lung adenocarcinoma who had undergone four cycles of chemotherapy with cisplatin and taxol. Am1010 cells were labeled with red fluorescent protein or green fluorescent protein. A total of eight sublines were isolated following in vitro exposure to cisplatin or taxol. The sublines differed with regard to their adhesion and proliferation properties, with certain sublines exhibiting an increased proliferation rate and/or decreased surface adhesion. Gene expression assays demonstrated that tenascin C; cyclin D1; collagen, type 1, α2; integrin α1; related RAS viral (r‑ras) oncogene homolog 2; platelet‑derived growth factor C; and Src homolog 2 domain containing in the focal adhesion pathway, and intercellular adhesion molecule 1, F11 receptor, claudin 7 and cadherin 1 in the cell adhesion pathway, varied in expression among the sublines. The results of the present study suggested that drug exposure may alter the aggressiveness and metastatic potential of cancer cells, which has important implications for cancer chemotherapy.

Figure 1

Am1010 fluorescent cells. (A) Am1010-GFP. The EGFP was expressed in Am1010 cells. (B) Am1010-RFP. The RFP (dsRed-2) gene was expressed in Am1010 cells. Magnification, ×100. GFP, green fluorescent protein; RFP, red fluorescent protein.

Figure 2

Am1010 sublines isolated by cisplatin exposure. (A) Am1010-cis-suspension-GFP: Suspended subline isolated by cisplatin exposure of Am1010-GFP. (B) Am1010-cis-adhesion-GFP: Attached subline isolated by cisplatin exposure of Am1010-GFP. (C) Am1010-cis-suspension-RFP: Suspended subline isolated by cisplatin exposure of Am1010-RFP. (D) Am1010-cis-adhesion-RFP: Attached subline isolated by cisplatin exposure of Am1010-RFP. Magnification, ×100. GFP, green fluorescent protein; RFP, red fluorescent protein.

Figure 3

Am1010 sublines isolated by taxol exposure. (A) Am1010-tax-suspension-GFP: Suspended subline isolated by taxol exposure of Am1010-GFP. (B) Am1010-tax-adhesion-GFP: Attached subline isolated by taxol exposure of Am1010-GFP. (C) Am1010-tax-suspension-RFP: Suspended subline isolated by taxol exposure of Am1010-RFP. (D) Am1010-tax-adhesion-RFP: Attached subline isolated by taxol exposure of Am1010-RFP. Magnification, ×100. GFP, green fluorescent protein; RFP, red fluorescent protein.

Figure 4

Relative gene expression changes in different sub-cell lines. Am1010 cells that attached poorly following drug exposure demonstrated upregulation of CCND1, TNC, COL1A2, ITGA1, RRAS2, PDGFC and SHC1 expression in the focal-adhesion pathway, and ICAM1 expression in the cell-adhesion pathway, in addition to downregulation of F11R, CLDN7 and CDH1 expression in the cell-adhesion pathway. Cells with improved attachment following drug exposure demonstrated that all eleven genes exhibited slight changes in the expression levels in cells with improved attachment. CCND1, cyclin D1; TNC, tenascin C; COL1A2, collagen, type 1, α2; ITGA1, integrin α1; RRAS2, related RAS viral (r-ras) oncogene homolog 2; PDGFC, platelet-derived growth factor C; SHC1, Src homolog 2 domain containing; ICAM1, intercellular adhesion molecule 1; CLDN7, claudin 7; F11R, F11 receptor; CDH1, cadherin 1; CA, Am1010-cis-adhesion; CS, Am1010-cis-suspension; TA; Am1010-tax-adhesion; TS, Am1010-tax-suspension; cis, cisplatin; tax, taxol.

Figure 5

Proliferation rates of the sublines. Am1010-cis-suspension, Am1010-cis-adhesion, Am1010-tax-suspension, and Am1010-tax-adhesion. Cis, cisplatin; tax, taxol.