Palmitic Acid Methyl Ester Induces G₂/M Arrest in Human Bone Marrow-Derived Mesenchymal Stem Cells via the p53/p21 Pathway

Figure 5

Involvement of intracellular acidosis and Ca²⁺ in the PAME-inhibited hBM-MSC proliferation. (a) Treatment with PAME (50 μM) for 48 h induced the intracellular acidosis, and this effect was enhanced by cotreatment with a Na⁺/H⁺ exchanger blocker, HOE 642 or EIPA. The top panel shows the BCECF intensity, an indicator of cytosolic pH, detected using flow cytometric analysis; the bottom panel shows a graph of quantitation of these data (). (b) Treatment with PAME (50 μM) for 48 h increased the intracellular Ca²⁺, and this effect was abolished by cotreatment with BAPTA-AM, a Ca²⁺ chelator. The top panel shows the Fluo-3 intensity, a fluorescence indicator of intracellular Ca²⁺; the bottom panel shows a graph of quantitation of these data (). (c) The PAME-decreased cell population was not significantly affected by cotreatment with HOC 642 or EIPA or BAPTA-AM. The cell population was detected by MTT assay (-20). (d) The PAME-increased cell accumulation at the G₂/M phase was not significantly affected by cotreatment with HOE 642 or BAPTA-AM. The cell population at the G₂/M phase was detected by flow cytometry using PI staining (). All data represent . , versus the control group; ^#, versus the PAME group. Con: control; Veh: vehicle; EIPA: ethyl isopropyl amiloride; HOE 642: cariporide; PI: propidium iodide.

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