Shifts in the concentrations of magnesium and calcium in early porcine and rat wound fluids activate the cell migratory response.

Abstract

Accruing evidence indicates that the levels of extracellular Mg2+ and Ca2+ can have a distinct impact on the adhesive and migratory activities of many cell types. The physiological relevance of these observations, however, has remained largely unexplored. In the present study, wound fluids collected throughout the early stages of cutaneous wound repair were examined for possible Mg2" and Ca2+ fluctuations. Early in the process, when cell migration into the wound site is initiated, Mg2+ is elevated and Ca2+ is reduced (Mg2+ :Ca2+ = 1). As wound healing progresses, wound fluid concentrations of Mg2+ and Ca2+ begin to return to normal plasma levels (Mg2+ :Ca2+ = 0.4). When macrophages, keratinocytes, fibroblasts, and endothelial cells were exposed to dialyzed wound fluid, the migration stimulated by undialyzed wound fluid was lost. Addition back to dialyzed wound fluid of 24 h, postinjury concentrations of Mg2+ and Ca2+ restored all migratory stimulus. This observed migration is approximately twofold greater than when normal plasma Mg2+ and Ca2+ concentrations are present. Changes in the levels of Mg2+ and Ca2+ in wound fluid occur during the same period that inflammatory cells, keratinocytes, fibroblasts, and neovasculature have been shown to migrate during wound healing in vivo. Together, these data suggest that the impact of these changes on integrins and E-cadherin may play a direct role in the activation and maintenance of the migratory phenotypes of the cells involved in the wound healing process. (J. Clin. Invest. 1995. 95:227-233.)

Activation of the α2β1 integrin‐mediated malignant phenotype on type I collagen in pancreatic cancer cells by shifts in the concentrations of extracellular Mg2+ and Ca2+

“…13 We have recently demonstrated that a 2 b 1 integrin-mediated pancreatic cancer cell adhesion to Type I collagen, an ECM protein shown to be highly upregulated in pancreatic cancer [14][15][16][17] and to promote the malignant phenotype in vitro and in vivo, [18][19][20][21][22][23][24][25] is promoted in 1.5 mM Mg 21 and inhibited in 1.5 mM Ca 21 , 21 and that the a 2 b 1 integrin from pancreatic cancer cell lysates bound specifically to Type I collagen by affinity chromatography in 3 mM Mg 21 , can be eluted with 3 mM Ca. 2126 These data are consistent with our previous observations regarding the a 2 b 1 integrin, Type I collagen, and the various cell types involved in cutaneous wound repair, [27][28][29] of which strong parallels to the pancreatic cancer paradigm have been described. 30,31 During normal cutaneous wound healing in vivo, shifts in the concentrations of extracellular Mg 21 and Ca 21 have been shown to occur early in the process, activating the a 2 b 1 integrin-mediated migration of various wound healing cell types on Type I collagen, including epithelial keratinocytes.…”

“…The cell adhesion and reversibility data together with previous affinity chromatography and immunoprecipitation results demonstrating that Ca 21 can elute the a 2 b 1 integrin from pancreatic cancer cell lysates bound specifically to Type I collagen-sepharose in Mg 2126 suggested that, as we have previously shown for fibroblasts, keratinocytes, endothelial cells and macrophages, [27][28][29] Ca 21 and Mg 21 could also be involved in the modulation of a 2 b 1 integrin-mediated pancreatic cancer cell migration on Type I collagen. We have previously demonstrated using anti-integrin function-blocking monoclonal antibodies in inhibition of cell migration assays, that the a 2 b 1 integrin specifically and exclusively mediates pancreatic cancer cell migration on Type I collagen, with no involvement from the a 1 b 1 integrin.…”

“…Also consistent with our previous studies of a 2 b 1 integrin-mediated WI38 fibroblast adhesion on Type I collagen substrates, 27 previous pancreatic cancer cell attachment in Mg 21 could be reversed by the addition of Ca 21 , and the extent of this detachment increased with increasing Ca 21 concentration. And like our previously published cell migration results using human wound healing cell types, including keratinocytes, endothelial cells, fibroblasts and macrophages, [27][28][29] we found that while BxPC-3 cells were migratory on Type I collagen in Mg 21 alone and not in Ca 21 alone, maximal migration was observed when these cations were utilized in combination with Mg 21 present at concentrations that promote maximal cell adhesion (3.5 mM) and Ca 21 present at concentrations less than Mg 21 . For example, maximal WI38 fibroblast adhesion on Type I collagen occurred in the presence of 1.5 mM Mg 21 , and maximal migration occurred at 1.5 mM Mg 21 with Ca 21 present at less than 1.5 mM.…”

“…[27][28][29] We have previously shown in porcine and rat partialand full-thickness models of cutaneous wound repair, however, that the local concentrations of extracellular magnesium and calcium shift early in the wound healing response, with decreased calcium and increased magnesium. [27][28][29] This pathophysiological shift activates the a 2 b 1 integrin-mediated migratory phenotype of keratinocytes, fibroblasts, endothelial cells and macrophages on Type I collagen. Our results indicate that, similar to these wound healing cell types, pancreatic cancer cells respond similarly to such divalent cation shifts, including increased a 2 b 1 integrin-mediated adhesion, migration and proliferation on Type I collagen.…”

“…30,31 During normal cutaneous wound healing in vivo, shifts in the concentrations of extracellular Mg 21 and Ca 21 have been shown to occur early in the process, activating the a 2 b 1 integrin-mediated migration of various wound healing cell types on Type I collagen, including epithelial keratinocytes. 29 This shift in extracellular divalent cation concentration is characterized by increased Mg 21 and decreased Ca 21 . Interestingly, similar shifts probably occur in pancreatic cancer as well as pancreatic juice, produced in the range of 1,500-2,000 mL/day, contains Mg 21 in the range of 137-244 lM and Ca 21 in the range of 0.111-0.197 lM.…”