Fig. 4

a-b Effect of survivin overexpression on the ECFP_em/Venus_em values in OCCs cultivated in serum-containing medium (a) or Neurobasal + B27 supplement (b). In both culture conditions, survivin overexpression significantly reduces the constitutive activity of Casp3 in CGCs. c Survivin overexpression results in a statistically significant increase in the intensity of 618 nm fluorescence emission (in arbitrary units) of HcRed1 (IF_emHcRed1) in CGCs transfected with pHcRed1-C1 or pHcRed1-C1-survivin. d-e Correlation between the intensity of 618 nm fluorescence emission (in arbitrary units) of HcRed1 (IF_emHcRed1) and ECFP_em/Venus_em in CGCs double transfected with pSCAT3-DEVD and pHcRed1-C1 (d) or pSCAT3-DEVD and pHcRed1-C1-survivin (e). Each dot represents a transfected cell. Note that IF_emHCRed1is not correlated with Casp3 activity in cells transfected with the survivin control vector (d), whereas IF_emHCRed1, and hence survivin level inside the cell (see text), is inversely correlated to Casp3 activity when CGCs are engineered to overexpress survivin (e). f-g Effect of H₂O₂ oxidative stress (5 mM) on the density of CGCs (f) or on the ECFP_em/Venus_em value (g) after double transfection with pSCAT3-DEVD and pHcRed1-C1, or pSCAT3-DEVD and pHcRed1-C1-survivin. Note that oxidative stress has no effect on either the number/area of transfected cells or the ECFP_em/Venus_em values when the cellular levels of survivin are not genetically manipulated. Survivin overexpression results in a statistically significant increase in cell density, and reduced, albeit not significantly, the ECFP_em/Venus_em values after H₂O₂. Error bars = SEM. ** P-value 0.01–0.001 % *** P-value < 0.001 %