title: Comparative studies of intracellular Ca2+ in strongly and weakly metastatic rat prostate cancer cell lines.
abstract: The metastatic ability of prostate cancer cells involves differential expression of ionic mechanisms. In the present study, using electrophysiological recordings and intracellular Ca2+ measurements, we investigated Ca2+ related signalling in two rat prostate cancer (MAT-LyLu and AT-2) cell lines of markedly different metastatic potential. Whole-cell voltage clamp experiments indicated the absence of an inward current carried through voltage-dependent Ca2+ channels in either cell line. A Ca2+-dependent component was also absent in the voltage-activated outward K+ currents. Indo-1 microfluorimetry confirmed these results and also revealed marked differences in the resting level of intracellular Ca2+ and the ability of the two cell lines to regulate intracellular Ca2+. The weakly metastatic AT-2 cells displayed a significantly higher resting intracellular Ca2+ than the related but strongly metastatic MAT-LyLu cell line. Increasing extracellular K+ decreased intracellular Ca2+ in the AT-2 but had no effect on intracellular Ca2+ levels in the MAT-LyLu cells. Furthermore, increasing extracellular Ca2+ increased intracellular Ca2+ in AT-2 but, again, had no effect on MAT-LyLu cells. These results suggested the presence of a tonic, voltage-independent Ca2+ permeation mechanism operating specifically in the AT-2 cells. The influx of Ca2+ into the AT-2 cells was suppressed by both CdCl2 (100-300 microM) and SKF-96365 (10-30 microM). It is concluded that the strongly metastatic MAT-LyLu cell line lacks a voltage-independent basal Ca2+ influx mechanism that is present in the weakly metastatic AT-2 cells.
authors.affiliation: Department of Biological Sciences, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Ding
authors.forename: J
authors.initials: J
authors.lastname: Robbins
authors.forename: S P
authors.initials: SP
authors.lastname: Fraser
authors.forename: J A
authors.initials: JA
authors.lastname: Grimes
authors.forename: M B A
authors.initials: MB
authors.lastname: Djamgoz
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D045744:Cell Line, Tumor / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D018408:Patch-Clamp Techniques; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology; D051381:Rats
chemical_list: D015220:Calcium Channels; D002118:Calcium