title: UV-B induced alteration in purinergic receptors and signaling on HaCaT keratinocytes.
abstract: Although there are a number of recognized risk factors resulting in cutaneous malignancies, very little is known about the exact mechanism. In keratinocytes different purinergic receptors have been implicated to play essential roles in deciding the fate of the cells through regulating proliferation and differentiation. While P2Y receptors seem to control the former, P2X receptors, among which the P2X(7) receptor is associated with the induction of apoptosis, are likely to be responsible for the latter. Forty mJ/cm(2) UV-B irradiation decreased the number of viable cells as assessed using MTT assay. This irradiation decreased the amount of both P2X(1) and P2Y(2) receptors and essentially destroyed the P2X(7) receptors in surviving cells. Morphology of ATP-induced Ca(2+) transients were altered in irradiated cells compared to control. The amplitude and the rate of rise of the transients were decreased and the return to resting [Ca(2+)](i) prolonged. This observation is consistent with the finding that in control cells mostly ionotropic, while in irradiated cells mostly metabotropic receptors were underlying the response to ATP. These alterations in the expression pattern of purinergic receptors and in the Ca(2+) transients could explain the observed decreased tendency for ATP-induced apoptosis and possibly contribute to the malignant transformation of keratinocytes.
authors.affiliation: Department of Physiology, Medical and Health Science Center, University of Debrecen, Debrecen H-4012, Hungary.
authors.forename: Olga
authors.initials: O
authors.lastname: Ruzsnavszky
authors.forename: Andrea
authors.initials: A
authors.lastname: Telek
authors.forename: Mónika
authors.initials: M
authors.lastname: Gönczi
authors.forename: Attila
authors.initials: A
authors.lastname: Balogh
authors.forename: Eva
authors.initials: E
authors.lastname: Remenyik
authors.forename: László
authors.initials: L
authors.lastname: Csernoch
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D011983:Receptors, Purinergic / Q000378:metabolism*; D058474:Receptors, Purinergic P2X1 / Q000378:metabolism; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism; D058473:Receptors, Purinergic P2Y2 / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D011983:Receptors, Purinergic; D058474:Receptors, Purinergic P2X1; D058486:Receptors, Purinergic P2X7; D058473:Receptors, Purinergic P2Y2; D000255:Adenosine Triphosphate; D002118:Calcium