NF-κB signaling is activated and confers resistance to apoptosis in three-dimensionally cultured EGFR-mutant lung adenocarcinoma cells.
Epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma cells in suspension undergo apoptosis to a greater extent than adherent cells in a monolayer when EGFR autophosphorylation is inhibited by EGFR tyrosine kinase inhibitors (TKIs). This suggests that cell adhesion to a culture dish may activate an anti-apoptotic signaling pathway other than the EGFR pathway. Since the microenvironment of cells cultured in a monolayer are substantially different to that of cells existing in three-dimension (3D) in vivo, we assessed whether two EGFR-mutant lung adenocarcinoma cell lines, HCC827 and H1975, were more resistant to EGFR TKI-induced apoptosis when cultured in a 3D extracellular matrix (ECM) as compared with in suspension. The ECM-adherent EGFR-mutant cells in 3D were significantly less sensitive to treatment with WZ4002, an EGFR TKI, than the suspended cells. Further, a marked degradation of IκBα, the inhibitor of nuclear factor (NF)-κB, was observed only in the 3D-cultured cells, leading to an increase in the activation of NF-κB. Moreover, the inhibition of NF-κB with pharmacological inhibitors enhanced EGFR TKI-induced apoptosis in 3D-cultured EGFR-mutant cells. These results suggest that inhibition of NF-κB signaling would render ECM-adherent EGFR-mutant lung adenocarcinoma cells in vivo more susceptible to EGFR TKI-induced cell death.
Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama, Japan. ysakuma@gancen.asahi.yokohama.jp
Yuji
Y
Sakuma
Yukiko
Y
Yamazaki
Yoshiyasu
Y
Nakamura
Mitsuyo
M
Yoshihara
Shoichi
S
Matsukuma
Shiro
S
Koizume
Yohei
Y
Miyagi
D000178:Acrylamides / Q000494:pharmacology; D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism*; D000077192:Adenocarcinoma of Lung; D000577:Amides / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D002448:Cell Adhesion; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics*; D005109:Extracellular Matrix; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D016328:NF-kappa B / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D013876:Thiophenes / Q000494:pharmacology
D000178:Acrylamides; D000577:Amides; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D013876:Thiophenes; C571455:WZ4002; C499326:2-((aminocarbonyl)amino)-5-(4-fluorophenyl)-3-thiophenecarboxamide; D066246:ErbB Receptors; D051550:I-kappa B Kinase