TY - JOUR
T1 - Multiple oncogenic changes (K-RASV12, p53 knockdown, mutant EGFRs, p16 bypass, telomerase) are not sufficient to confer a full malignant phenotype on human bronchial epithelial cells
AU - Sato, Mitsuo
AU - Vaughan, Melville B.
AU - Girard, Luc
AU - Peyton, Michael
AU - Lee, Woochang
AU - Shames, David S.
AU - Ramirez, Ruben D.
AU - Sunaga, Noriaki
AU - Gazdar, Adi F.
AU - Shay, Jerry W.
AU - Minna, John D.
PY - 2006/2/15
Y1 - 2006/2/15
N2 - We evaluated the contribution of three genetic alterations (p53 knockdown, K-RASV12, and mutant EGFR) to lung tumorigenesis using human bronchial epithelial cells (HBEC) immortalized with telomerase and Cdk4-mediated p16 bypass. RNA interference p53 knockdown or oncogenic K-RASV12 resulted in enhanced anchorage-independent growth and increased saturation density of HBECs. The combination of p53 knockdown and K-RASV12 further enhanced the tumorigenic phenotype with increased growth in soft agar and an invasive phenotype in three-dimensional organotypic cultures but failed to cause HBECs to form tumors in nude mice. Growth of HBECs was highly dependent on epidermal growth factor (EGF) and completely inhibited by EGF receptor (EGFR) tyrosine kinase inhibitors, which induced G1 arrest. Introduction of EGFR mutations E746-A750 del and L858R progressed HBECs toward malignancy as measured by soft agar growth, including EGF-independent growth, but failed to induce tumor formation. Mutant EGFRs were associated with higher levels of phospho-Akt, phospho-signal transducers and activators of transcription 3 [but not phospho-extracellular signal-regulated kinase (ERK) 1/2], and increased expression of DUSP6/MKP-3 phosphatase (an inhibitor of phospho-ERK1/2). These results indicate that (a) the HBEC model system is a powerful new approach to assess the contribution of individual and combinations of genetic alterations to lung cancer pathogenesis; (b) a combination of four genetic alterations, including human telomerase reverse transcriptase overexpression, bypass of p16/RB and p53 pathways, and mutant K-RAS V12 or mutant EGFR, is still not sufficient for HBECs to completely transform to cancer; and (c) EGFR tyrosine kinase inhibitors inhibit the growth of preneoplastic HBEC cells, suggesting their potential for chemoprevention.
AB - We evaluated the contribution of three genetic alterations (p53 knockdown, K-RASV12, and mutant EGFR) to lung tumorigenesis using human bronchial epithelial cells (HBEC) immortalized with telomerase and Cdk4-mediated p16 bypass. RNA interference p53 knockdown or oncogenic K-RASV12 resulted in enhanced anchorage-independent growth and increased saturation density of HBECs. The combination of p53 knockdown and K-RASV12 further enhanced the tumorigenic phenotype with increased growth in soft agar and an invasive phenotype in three-dimensional organotypic cultures but failed to cause HBECs to form tumors in nude mice. Growth of HBECs was highly dependent on epidermal growth factor (EGF) and completely inhibited by EGF receptor (EGFR) tyrosine kinase inhibitors, which induced G1 arrest. Introduction of EGFR mutations E746-A750 del and L858R progressed HBECs toward malignancy as measured by soft agar growth, including EGF-independent growth, but failed to induce tumor formation. Mutant EGFRs were associated with higher levels of phospho-Akt, phospho-signal transducers and activators of transcription 3 [but not phospho-extracellular signal-regulated kinase (ERK) 1/2], and increased expression of DUSP6/MKP-3 phosphatase (an inhibitor of phospho-ERK1/2). These results indicate that (a) the HBEC model system is a powerful new approach to assess the contribution of individual and combinations of genetic alterations to lung cancer pathogenesis; (b) a combination of four genetic alterations, including human telomerase reverse transcriptase overexpression, bypass of p16/RB and p53 pathways, and mutant K-RAS V12 or mutant EGFR, is still not sufficient for HBECs to completely transform to cancer; and (c) EGFR tyrosine kinase inhibitors inhibit the growth of preneoplastic HBEC cells, suggesting their potential for chemoprevention.
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U2 - 10.1158/0008-5472.CAN-05-2521
DO - 10.1158/0008-5472.CAN-05-2521
M3 - Article
C2 - 16489012
AN - SCOPUS:33644507072
SN - 0008-5472
VL - 66
SP - 2116
EP - 2128
JO - Cancer research
JF - Cancer research
IS - 4
ER -