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Distinct regulation of pH in and [Ca 2+ ] in in human melanoma cells with different metastatic potential
Author(s) -
MartínezZaguilán Raul,
Martinez Gloria M.,
Gomez Araceli,
Hendrix Mary J. C.,
Gillies Robert J.
Publication year - 1998
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199807)176:1<196::aid-jcp21>3.0.co;2-4
Subject(s) - melanoma , metastatic melanoma , cancer research , chemistry , biology , microbiology and biotechnology , computational biology
We investigated whether alterations in the mechanisms involved in intracellular pH (pH in ) and intracellular calcium ([Ca 2+ ] in ) homeostasis are associated with the metastatic potential of poorly (A375P) and highly (C8161) metastatic human melanoma cells. We monitored pH in and [Ca 2+ ] in simultaneously, using the fluorescence of SNARF‐1 and Fura‐2, respectively. Our results indicated that steady‐state pH in and [Ca 2+ ] in between these cell types were not significantly different. Treatment of cells with NH 4 Cl resulted in larger pH in increases in highly than in poorly metastatic cells, suggesting that C8161 cells have a lower H + buffering capacity than A375P. NH 4 Cl treatment also increased [Ca 2+ ] in only in C8161 cells. To determine if the changes in [Ca 2+ ] in triggered by NH 4 Cl treatment were due to alterations in either H + ‐ or Ca 2+ ‐buffering capacity, cells were treated with the Ca 2+ ‐ionophore 4Br‐A23187, to alter [Ca 2+ ] in . The magnitude of the ionophore‐induced [Ca 2+ ] in increase was slightly greater in C8161 cells than in A375P. Moreover, A375P cells recover from the ionophore‐induced [Ca 2+ ] in load, whereas C8161 cells did not, suggesting that A375P may exhibit distinct [Ca 2+ ] in regulatory mechanisms than C8161 cells, to recover from Ca 2+ loads. Removal of extracellular Ca 2+ ([Ca 2+ ] ex ) decreased [Ca 2+ ] in in both cell types at the same extent. Ionophore treatment in the absence of [Ca 2+ ] ex transiently increased [Ca 2+ ] in in C8161, but not in A375P cells. Endoplasmic reticulum (ER) Ca 2+ ‐ATPase inhibitors such as cyclopiazonic acid (CPA) and thapsigargin (TG) increased steady‐state [Ca 2+ ] in only in C8161 cells. Together, these data suggest that the contribution of intracellular Ca 2+ stores for [Ca 2+ ] in homeostasis is greater in highly than in poorly metastatic cells. Bafilomycin treatment, to inhibit V‐type H + ‐ATPases, corroborated our previous results that V‐H + ‐ATPases are functionally expressed at the plasma membranes of highly metastatic, but not in poorly metastatic cells in and [Ca 2+ ] in regulatory mechanisms are present in poorly and highly metastatic human melanoma cells. J. Cell. Physiol. 176:196–205, 1998. © 1998 Wiley‐Liss, Inc.