Expression of functional P2-purinergic receptors in primary cultures of human colorectal carcinoma cells.
Primary cell cultures of human colorectal carcinomas were established and characterized immunocytochemically. In the isolated cancer cells intracellular Ca2+ concentrations ([Ca2+]i) were measured by the fura-2 method. Stimulation with either extracellular ATP or UTP caused a biphasic rise of [Ca2+]i in a dose-dependent manner and cross-desensitization between both nucleotides was observed. The rank order of potency was ATP >== UTP > ATP-gamma-S > ADP > adenosine which is characteristic for a P2U-receptor subtype. Selective agonists of P1-, or P2X- purinoceptors had no effect on [Ca2+]i. The initial rise in [Ca2+]i was independent of extracellular calcium [Ca2+]e, whereas the second phase was not observed under [Ca2+]e-free conditions suggesting a capacitative Ca2+-entry-mechanism. Intracellular Ca2+ mobilization was proven by use of the Ca2+-ATPase inhibitor thapsigargin. P2U-specific mRNA could be detected by RT-PCR in both colorectal tumor tissues and in the human colorectal cancer cell line HT 29. In HT 29 cells, the hydrolysis-resistant ATP analog ATP-gamma-S inhibited cell proliferation and, also, induced apoptosis in a dose-dependent manner. Thus, human colorectal cancer cells express functional P2U-receptors which may play a role in the regulation of cell proliferation and apoptosis.
Höpfner
M
M
Abteilung Innere Medizin/Gastroenterologie, Abteilung Allgemein-, Gefäss-, und Thoraxchirugie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, Berlin, 12200, Germany.
Lemmer
K
K
Jansen
A
A
Hanski
C
C
Riecken
E O
EO
Gavish
M
M
Mann
B
B
Buhr
H
H
Glassmeier
G
G
Scherübl
H
H
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000368:Aged; D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D019073:HT29 Cells; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D058906:Purinergic P1 Receptor Agonists; D058910:Purinergic P2 Receptor Agonists; D012333:RNA, Messenger / Q000032:analysis; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058473:Receptors, Purinergic P2Y2; D014407:Tumor Cells, Cultured; D014544:Uridine Triphosphate / Q000494:pharmacology
C546385:P2RY2 protein, human; D058906:Purinergic P1 Receptor Agonists; D058910:Purinergic P2 Receptor Agonists; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D002118:Calcium; D014544:Uridine Triphosphate