Cell senescence after α-amylase treatment A possible influence
of α-amylase on cell senescence was investigated by determination of SA-βGANT61 in vitro -gal-positive cells. Without treatment, P2-F344 cells showed significantly increased numbers of SA-β-gal-positive cells compared to P1-cells Blebbistatin mouse (2-3fold). There were no significant differences in cell growth or SA-β-gal-positive cells after 5 U/ml. α-Amylase at 50 U/ml significantly decreased number of cells in P1-F344 cells, but not in P2-F344 or P2-Lewis, although there was a tendency for P2-F344 (Table 1). Alteration in SA-β-gal-positive cells was not strictly combined with a change in cell number after α-amylase, because cell counts were decreased in P1-F344 cells, but SA-β-gal-positive cells ABT-888 cell line were not changed. Moreover, there was a significant increase in SA-β-gal-positive P2-F344 cells by
50 U/ml, but no significant alteration in number of cells (Table 1). Lewis cells (P2) did not respond to α-amylase in this experiment. Table 1 SA-β-gal assay and cell number after α-amylase treatment in F344 and Lewis cells F344, P1 F344, P2 Lewis, P2 SA-β-gal assay SA-β-gal-positive cells (%) SA-β-gal-positive cells (%) SA-β-gal-positive cells (%) Control (H 2 O) 11.94 ± 1.81 27.35 ± 3.28 33.82 ± 1.48 5 U/ml α-amylase 13.86 ± 1.41 37.15 ± 3.19 34.12 ± 3.20 50 U/ml α-amylase 11.83 ± 2.39 39.48 ± 3.47* 29.81 ± 2.78 n.s. *H2O vs. 50 U/ml n.s. F344, P1 F344, P2 Lewis, P2 Cell counts Number of cells/well Number of cells/well Number of cells/well Control (H 2 O) 17,250 ± 1,377 4,500 ± 577 4,188 ± 567 5 U/ml α-amylase 17,958 ± 1,514 3,958 ± 240 5,292 ± 163 50 U/ml α-amylase 11,833 ± 870* 2,371 ± 344 4,483 ± 464 *H2O vs. 50 U/ml n.s. n.s. α-Amylase (50 U/ml) SDHB decreased the number of cells only in P1-F344-cells, but not in P2-F344- and P2-Lewis-cells. Proportion of SA-β-gal-positive cells did not correlate with cell number, as this amount of cells was not altered
in P1-F344 cells, but significantly increased in P2-F344 cells after 50 U/ml α-amylase. No difference at all was observed in Lewis-cells (P2) and after 5 U/ml α-amylase. Mean and SEM are shown for three wells per group (cell counts) or 6-9 sections (SA-β-gal assay). Significant differences (p < 0.05) vs. control cells (One-way-ANOVA and Bonferroni for selected pairs) are indicated by asterisk. In MaCa 700 cells, a primary culture from a human breast tumor, α-amylase caused a significant decrease in number of cells after 1.25 and 125 U/ml α-amylase for 2 days (Figure 4a). The portion of SA-β-gal-positive cells was significantly increased only after 125 U/ml. However, there was a tendency for a concentration-dependent increase of SA-β-gal-positive MaCa 700 cells (Figure 4a).