Preferential expression of the secreted and membrane forms of tumor endothelial marker 7 transcripts in osteosarcoma.
BACKGROUND
High expression of tumor endothelial marker 7 (TEM7) is correlated with osteogenic sarcoma (OS) metastasis and poor survival of patients. The TEM7 gene produces four alternatively spliced transcripts with distinct functional domains; the expression pattern of these transcripts in OS is unknown.


METHODS
mRNA expression was assessed in 5 OS cell lines, 7 normal bone, and 9 OS tumor specimens by reverse transcriptase polymerase chain reaction.


RESULTS
All OS cell lines, 6/9 tumors but none of the bone specimens expressed mRNA of TEM7 secreted forms 1 and 2. A total of 3/5 OS cell lines, 8/9 of tumors and 4/7 of bone specimens expressed mRNA of the TEM7 intracellular form. One out of 5 cell lines, 2/7 tumors and none of the bone specimens expressed mRNA of the TEM7 membrane form. The secreted forms had 20-fold higher expression in metastatic (LM7) compared to non-metastatic (SAOS-2) cells.


CONCLUSIONS
The mRNA of secreted and the membrane forms of TEM7 are preferentially expressed in OS.
Halder
Chandralekha
C
Department of Orthopedic Research, Mayo Clinic, Experimental Pathology, Rochester, MN 55905, USA.
Ossendorf
Christian
C
Maran
Avudaiappan
A
Yaszemski
Michael
M
Bolander
Mark E
ME
Fuchs
Bruno
B
Sarkar
Gobinda
G
D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; C510620:PLXDC1 protein, human; D020033:Protein Isoforms; D012333:RNA, Messenger; D011956:Receptors, Cell Surface