Identification of squamous cell carcinoma associated proteins by proteomics and loss of beta tropomyosin expression in esophageal cancer.
OBJECTIVE
To assess the proteome of normal versus tumor tissue in squamous cell carcinoma of the esophagus (SCCE) in Iranian patients and compare our results with former reports by using proteomics.


METHODS
Protein was extracted from normal and tumor tissues. Two dimensional electrophoresis was carried out and spots with differential expression were identified with mass spectrometry. RNA extraction and RT-PCR along with immunodetection were performed.


RESULTS
Fourteen proteins were found whose expression levels differed in tumor compared to normal tissues. Mass spectrometric analysis resulted in the identification of beta-tropomyosin (TMbeta), myosin light chain 2 (and its isoform), myosin regulatory light chain 2, peroxyredoxin 2, annexin I and an unknown polypeptide as the down regulated polypeptides in tumor tissue. Heat shock protein 70 (HSP70), TPM4-ALK fusion oncoprotein 2, myosin light polypeptide 6, keratin I, GH16431p and calreticulin were the up-regulated polypeptides found in tumor tissue. Several of these proteins, such as TMbeta, HSP70, annexin I, calreticulin, TPM4-ALK and isoforms of myosins, have been well recognized in tumorigenesis of esophageal or other types of cancers.


CONCLUSIONS
Our study not only supports the involvement of some of the formerly reported proteins in SCCE but also introduces additional proteins found to be lost in SCCE, including TMbeta.
Jazii
Ferdous-Rastgar
FR
National Institute of Genetic Engineering and Biotechnology, PO BOX 14155 6343, Tehran, Iran. rastgar_jazii@yahoo.com
Najafi
Zahra
Z
Malekzadeh
Reza
R
Conrads
Thomas-P
TP
Ziaee
Abed-Ali
AA
Abnet
Christian
C
Yazdznbod
Mansour
M
Karkhane
Ali-Asghar
AA
Salekdeh
Ghasem-H
GH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D011506:Proteins / Q000302:isolation & purification; D040901:Proteomics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014335:Tropomyosin / Q000378:metabolism*
D011506:Proteins; D014335:Tropomyosin