Purification and identification of a 7.6-kDa protein in media conditioned by superinvasive cancer cells.
BACKGROUND
Selection of the human drug sensitive and invasive cell line (MDA-MB-435S-F) with the chemotherapeutic agent paclitaxel, resulted in the development of drug resistant cell lines displaying enhanced invasion-related characteristics.


METHODS
Serum-free conditioned media from the human cancer drug-sensitive and invasive cell line (MDA-MB-435S-F) and its paclitaxel-resistant superinvasive variant (MDA-MB-435S-F/Taxol10p4pSI) were analyzed using Surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS).


RESULTS
A differentially expressed protein was observed at 7.6 kDa, which was 4-fold up-regulated in MDA-MB-435S-F/Taxol10p4pSI. The differentially expressed protein was identified using matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS), as a fragment of bovine transferrin. The transferrin receptor was also found to be overexpressed in the superinvasive cell line.


CONCLUSIONS
Cleavage of serum proteins such as transferrin could provide a valuable source of markers for malignant tumours and could also play a role in aspects of cancer pathogenesis, such as tumour cachexia.
Dowling
P
P
National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland. paul.dowling@dcu.ie
Maurya
P
P
Meleady
P
P
Glynn
S A
SA
Dowd
A J
AJ
Henry
M
M
Clynes
M
M
D000328:Adult; D014408:Biomarkers, Tumor / Q000737:chemistry / Q000302:isolation & purification*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000737:chemistry / Q000302:isolation & purification*; D017239:Paclitaxel / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification*; D011990:Receptors, Transferrin / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D014168:Transferrin / Q000737:chemistry / Q000302:isolation & purification*
D014408:Biomarkers, Tumor; D017077:Culture Media, Conditioned; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D011990:Receptors, Transferrin; D014168:Transferrin; D017239:Paclitaxel