Irreversible pan-ErbB tyrosine kinase inhibitor CI-1033 induces caspase-independent apoptosis in colorectal cancer DiFi cell line.
The epidermal growth factor receptor (EGFR) is overexpressed in the majority of colorectal carcinomas and represents a target for therapeutic interventions with signal transduction inhibitors. We investigated the ability of CI-1033 to induce apoptosis and inhibition of proliferation in the colorectal cancer cell lines DiFi and Caco-2, which both express high levels of EGFR. While in Caco-2 cells CI-1033 treatment at a concentration 0.1 microM for 72 hours demonstrated only antiproliferative (53.7 +/- 4.3%) but no pro-apoptotic effects, treatment of DiFi cells resulted in a reduced proliferation rate (31.4 +/- 3.1%) and in apoptosis (44.2 +/- 8.9%). In order to define proteins involved in the regulation of apoptosis, we aimed to determine differences in the proteome profile of both cell lines before and after treatment with CI-1033. Cellular proteins were analyzed by 2-D gel electrophoresis followed by computational image analysis and mass spectrometry. Our data show that DiFi cells differ from Caco-2 cells in nine significantly upregulated proteins, and their potential role in apoptosis is described. We demonstrate that induction of apoptosis was triggered via caspase-independent pathways. Overexpression of leukocyte elastase inhibitor (LEI) and translocation of cathepsin D to the cytosol accompanied by upregulation of other defined proteins resulted in Bax-independent AIF translocation from mitochondria into the nucleus and apoptosis. Definition of these proteins can pave the way for functional studies and contribute to a better understanding of the effects of CI-1033 and the pathways of caspase-independent cell death.
Skvortsov
S
S
Department of Internal Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020 Innsbruck, Austria. sskvortsov@hotmail.com
Skvortsova
I
I
Sarg
B
B
Loeffler-Ragg
J
J
Lindner
H
H
Lukas
P
P
Tabernero
J
J
Zwierzina
H
H
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000502:physiology; D018938:Caco-2 Cells; D053148:Caspase 3; D020169:Caspases / Q000502:physiology; D002402:Cathepsin D / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms; D000077156:Gefitinib; D016147:Genes, Tumor Suppressor / Q000502:physiology; D006801:Humans; D009025:Morpholines / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D011799:Quinazolines / Q000494:pharmacology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors*; D015843:Serpins / Q000502:physiology
D000590:Amino Acid Chloromethyl Ketones; D051033:Apoptosis Inducing Factor; D053148:Caspase 3; D020169:Caspases; D002402:Cathepsin D; D000077156:Gefitinib; D009025:Morpholines; D019253:Proto-Oncogene Proteins c-bcl-2; D011799:Quinazolines; D018719:Erb-b2 Receptor Tyrosine Kinases; D015843:Serpins; C085344:SERPIN-B5; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C420268:Canertinib; C505407:CASP3 protein, human