Decreasing Extracellular pH Increases CD13 Receptor Surface Content and Alters the Metabolism of HL60 Cells Cultured in Stirred Tank Bioreactors

Abstract

Flow cytometry and Northern blotting were used to examine the effects of extracellular pH on CD13 receptor surface content and mRNA levels of HL60 (human promyelocytic leukemia) cells. Decreasing culture pH (7.4, 7.2, and 7.0) increased the CD13 receptor surface content of HL60 cells cultured at low agitation intensity (80 rpm) in 2-L bioreactors. Unlike our earlier findings on the effects of increasing agitation rates and serum concentrations, changes in CD13 receptor content in response to decreasing culture pH did not correlate with changes in CD13 mRNA levels. Decreasing culture pH also decreased the average HL60 cell size. HL60 cells cultured at pH 7.0 and 7.2 exhibited glucose consumption and lactate production rates that were approximately 30-40% and 20-30% lower, respectively, than values of cells cultured at pH 7.4.

Hydrochloric acid alters the effect of l-glutamic acid on cell viability in human neuroblastoma cell cultures

“…Extracellular pH was also an important parameter in the culturing of mammalian cells. pH variations may have a profound effect on cell physiology (Akatov et al, 1985;McAdams et al, 1997;Miller et al, 1988;Kaiser andCurthoys, 1991) metabolism (McDowell andPapoutsakis, 1998) and protein expression (Katafuchi et al, 1993). Acidosis for example may induce the necrosis and apoptosis of cultured hippocampal neurons (Ding et al, 2000).…”

“…A decrease in extracellular pH may also have a strong effect on cell metabolism. Cells cultured at pH 7.0 and 7.2 exhibited glucose consumption and lactate production rates that were from 20% to 40% lower than cultures at pH 7.4 (McDowell and Papoutsakis, 1998). It has also been previously demonstrated that changes in extracellular pH can modify the expression levels of cell-surface proteins and surface receptors (Katafuchi et al, 1993) involved in the mediation of vital functions such as cell proliferation (Akatov et al, 1985), cell differentiation (McAdams et al, 1997), cell metabolism (Miller et al, 1988) and mRNA production (Kaiser and Curthoys, 1991).…”

FT-IR spectromicroscopy of mammalian cell cultures during necrosis and apoptosis induced by drugs

“…Apoptosis was induced treating cells with Etoposide phosphate (VP-16) (50 µM) or Cis-Platinum (Cis-P) (25 µM) [7,17]. After drug treatment, either at 8, 16, 24 and 32 h or at different drug concentration (1,5,10,20,30 µM for 48 h), cells were collected by centrifugation at 1500 rpm for 5 min, washed twice with 100 µl of PBS and resuspended in 10 µl PBS for FT-IR analysis. Necrosis of Jurkat cells [30] was induced at a concentration of 5 × 10 5 cells/ml by depriving the cell suspension of oxygen for 24, 48 and 96 h. Apoptosis or necrosis was evaluated by Propidium iodide and FACScan flow cytometer (Becton-Dickinson).…”

“…These findings probably indicated that with respect to oxidative stress [26], fatty acid metabolism, evaluated by change in the ν as (CH 3 ) absorbance [26], was changing in apoptotic Jurkat cells. It was reported that the tendency in the increase in the CH 2 /CH 3 absorbance ratio might depends by cell growth conditions [3,14,20,21,33]. Because apoptosis lead to cell shrinkage [16], a decrease in the cellular volume should correspond to a relative increase in the surface area.…”

Culture of human T cells in stirred bioreactors for cellular immunotherapy applications: Shear, proliferation, and the IL-2 receptor

“…The use of stirred vessel culture systems has many advantages including uniform culture conditions, ease of sampling, and well-developed systems for actively controlling process parameters such as pH and dissolved oxygen concentration, both of which can have profound effects on the proliferation and properties of the cells (Katafuchi et al, 1993;Koller et al, 1992;McAdams et al, 1997;McDowell and Papoutsakis, 1998a). Perfusion feeding culture strategies, used to obtain very high cell densities, are also well developed for stirred vessel culture systems and are readily implementable (Lang and Schuerch, 1998;Takazawa and Tokashiki, 1989).…”