Figure 1.
Structures of ortho Zn(II) meso-tetrakis(N-alkylpyridinium-2-yl)porphyrins investigated in this study and the para platinum analog (PtTM-4-PyP) [36] of the methyl Zn-porphyrin (ZnTM-2-PyP).
PtTM-4-PyP, Pt(II) meso-tetrakis(N-methylpyridinium-4-yl)porphyrin; Zn porphyrin, Zn(II) meso-tetrakis(N-alkylpyridinium-2-yl)porphyrin, alkyl being methyl (M, ZnTM-2-PyP), n-butyl (nBu, ZnTnBu-2-PyP), n-hexyl (nHex, ZnTnHex-2-PyP).
Table 1.
Lipophilicity of Zn(II) meso-tetrakis(N-alkylpyridinium-2-yl)porphyrins.
Figure 2.
Effect of phototreatment with Zn porphyrins on MTT reduction and respiration.
Cells were preincubated for 24 h with Zn porphyrins, washed, resuspended in PBS and illuminated for 30 minutes. A: MTT reduction by cells illuminated after preincubation with ortho methyl, butyl or hexyl Zn porphyrins. Concentrations of compounds causing 50% inhibition of MTT reduction (IC50) compared to controls are presented; B: Oxygen consumption by cells preincubated with 5 µM Zn porphyrins and illuminated. Mean ± S.E. is presented (n = 4); * p<0.05 compared to control.
Figure 3.
Effect of phototreatment on respiration by isolated mitochondria.
Suspensions of intact mitochondria were incubated for 15 minutes with 1 and 5 µM ZnTM-2-PyP, ZnTnBu-2-PyP or ZnTnHex-2-PyP and were then illuminated for 30 minutes. Dark controls and controls with mitochondria illuminated in the absence of photosensitizer were run in parallel. Respiration rate of untreated mitochondria was taken as 100%. (n = 3); * p<0.05 compared to control.
Figure 4.
Fluorescence microscopy images of cells preincubated with Zn-porphyrins.
I: ZnTM-2-PyP; II: ZnTE-2-PyP; III, IV: ZnTnBu-2-PyP; V, VI: ZnTnHex-2-PyP. A: Cells incubated for in the dark with Zn-porphyrin; B: Costaining with DIOC6(3) iodide (II, IV, V), Lysosensor (III), or MitoTracker (VI) C: Overlay.
Figure 5.
Photoinactivation of cytochrome c oxidase in intact cells.
Cells were washed after 24 hours incubation with 5 and 10 µM of ZnTM-2-PyP, ZnTnBu-2-PyP or ZnTnHex-2-PyP and were illuminated for 30 minutes. Cytochrome c oxidase activity was determined in cell-free lysates. Data are expressed as mean ± SE (n = 4); *p<0.05 compared to control.
Figure 6.
Photoinactivation of cytochrome c oxidase in intact mitochondria.
Mitochondria were incubated with 1 and 5 µM ZnTM-2-PyP, ZnTnBu-2-PyP or ZnTnHex-2-PyP for 15 minutes and were then illuminated for 30 minutes. Data are expressed as mean ± SE (n = 4). *p<0.05 compared to control.
Figure 7.
Photo-inactivation of cytochrome c oxidase in permeabilized mitochondria incubated with 10 µM ZnTM-2-PyP, ZnTnBu-2-PyP or ZnTnHex-2-PyP for 30 minutes and then illuminated for 30 minutes.
Data are expressed as mean ± SE (n = 4). * p<0.05 compared to control.