The tumor-selective somatostatin analog, TT2-32 induces a biphasic activation of phosphotyrosine phosphatase activity in human colon tumor cell line, SW620.
Somatostatin has been demonstrated to activate phosphotyrosine phosphatases (PTPases) in pancreatic cells. In this work we studied the effect of a tumor-selective somatostatin structural derivative, TT2-32, on the PTPase activity in the SW620 human colon tumor cell line. TT2-32 caused a strong inhibition of cell proliferation. In response to TT2-32 we found a rapid and sustained increase (5-30 min) in PTPase activity showing two maxima at 0.1 and 30 microM concentrations, respectively. During short-term incubation tyrosine kinase activity was much less affected by TT2-32. TT2-32-induced activation of PTPases may be an important early step in the signaling cascade in the inhibition of cell proliferation in colon carcinomas.
Vántus
T
T
Department of Biochemistry 1, Joint Research Organisation of Hungarian Academy of Sciences, Semmelweis Medical University, Budapest.
Csermely
P
P
Teplán
I
I
Kéri
G
G
D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D008969:Molecular Sequence Data; D017027:Protein Tyrosine Phosphatases / Q000187:drug effects* / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000201:enzymology
D000970:Antineoplastic Agents; C094462:TT2-32; D013004:Somatostatin; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases