Intracellular pH and calcium homeostasis in cultured Kaposi sarcoma and endothelial cells (Meeting abstract). NLM AIDSLINE Important note: Information in this article was accurate in 1994. The state of the art may have changed since the publication date.

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Intracellular pH and calcium homeostasis in cultured Kaposi sarcoma and endothelial cells (Meeting abstract).

FASEB J; 7(7):A1100 1993. Unique Identifier : AIDSLINE ICDB/94698514
Chinnock B; Martinez-Zaguilan R; Way D; Witte MH; Wald-Hopkins S; Gillies R; Univ. of Arizona Coll. of Medicine, Tucson, AZ 85724

Abstract: Changes in intracellular pH (pHi) and calcium (Ca2+) play a major role in signal transduction leading to cell growth, differentiation and transformation. In some tumor cell lines, vacuolar-type H+-ATPases (V-HA) are important in pHi regulation. To clarify the neoplastic nature and endothelial origin of Kaposi sarcoma (KS), pHi, and Ca2+ and functional expression of V-HA were evaluated in cultured endothelial marker-positive KS cells derived from AIDS-KS skin lesions and compared to human umbilical vein endothelial cells (HUVEC) using fluorescent spectroscopy with pHi indicator SNARF-1 and Ca2+(i) indicator fura-2. We found that, whereas pHi recovery from acid loading in the absence of Na+(-) and HCO3(-) was biphasic in HUVEC with a lag time of 3-5 min and was reduced by V-HA inhibitors, KS cells did not recover (as shown in a graph). Moreover, removal of Na+ and consequent acidification had no effect on Ca2+(i) in HUVEC but transiently increased Ca2+(i) approx 150% in KS cells. This increase was unaffected by Ca2+(i)-free media, suggesting that it is not due to Na+/Ca2+ exchange but rather to a H+-, Na+-, or IP3-sensitive Ca2+ pool. In conclusion, pHi and Ca2+(i) regulatory mechanisms in KS cells differ from control endothelial cells. These observations may reflect different cell lineages or transdifferentiation/transformation as the basis for abnormal vascular proliferation characteristic of the KS lesion in vivo.
Keywords: Calcium/*METABOLISM Cells, Cultured Endothelium, Vascular/CYTOLOGY/*METABOLISM *Homeostasis Human Hydrogen-Ion Concentration Sarcoma, Kaposi's/*METABOLISM/PATHOLOGY Sodium/METABOLISM Spectrometry, Fluorescence Tumor Cells, Cultured ABSTRACTKWDcalcium/KWDmetabolismcells,culturedendothelium,vascular/cytology/KWDmetabolismKWDhomeostasishumanhydrogen-ionconcentrationsarcoma,kaposi's/KWDmetabolism/pathologysodium/metabolismspectrometry,fluorescencetumorcells,culturedabstract
940830
M9480802

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