Anti-tumor activity of erlotinib in the BxPC-3 pancreatic cancer cell line.
OBJECTIVE
To investigate the effect and mechanism of action of erlotinib, an epidermal growth factor receptor (EGFR) small molecule tyrosine kinase inhibitor (TKI), in the human pancreatic cancer cell line BxPC-3 both in vitro and in vivo.


METHODS
In vitro, human pancreatic cancer cell line BxPC-3 was exposed to varying concentrations of erlotinib, and its effects on proliferation, cell cycle distribution, apoptosis and the expression of pro- and antiapoptotic factors such as bcl-2, bcl-xl, bax and bak, and the expression of vascular endothelial cell growth factor (VEGF) were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis, terminal deoxynucleotidyl transferase-mediated nick end labeling assay (TUNEL), and reverse transcription-polymerase chain reaction (RT-PCR). Potential effect of erlotinib on angiogenesis was examined by tube formation assay. Tumor growth suppression was observed in xenografted nude mice with pancreatic cancer in vivo. Immunohistochemical (IHC) staining for EGFR and factor VIII-related antigen was undertaken to detect the microvessel density and VEGF expression in tumor tissue in xenograft nude mice.


RESULTS
Erlotinib, as a single agent, repressed BxPC-3 cell growth in a dose-dependent manner, triggered G(1) arrest and induced cell apoptosis, and suppressed capillary formation of endothelium in vitro. Expressions of VEGF were significantly down-regulated at a high concentration of 200 mumol/L, however, the expressions of bcl-2 and bcl-xl were decreased at 50 mumol/L. In vivo, Erlotinib-treated mice demonstrated a reduced tumor volume, weight and microvessel density as compared to the control. IHC staining showed decreased expression of EGFR and RT-PCR had lower VEGF expression in treated mice.


CONCLUSIONS
The in vitro and in vivo findings provide evidence that BxPC-3 cells are inhibited with erlotinib treatment. Inhibition of EGFR may be a promising adjuvant chemotherapy strategy in pancreatic cancer treatment.
Lu
Ying-Ying
YY
Department of Gastroenterology, Shanghai First People's Hospital, Shanghai Jiao Tong University, 100 Haining Road, Hongkou District, Shanghai, China.
Jing
Da-Dao
DD
Xu
Ming
M
Wu
Kai
K
Wang
Xing-Peng
XP
D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D000069347:Erlotinib Hydrochloride; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use*; D014183:Transplantation, Heterologous; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors