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Somatostatin Analogues for Receptor Targeted Photodynamic Therapy
Figure 3
(A) Kinetics of fluorescence bleaching of photosensitizers (▪) Ce6, (
) conjugate 1 and (
) conjugate 2 in PBS under 652 nm irradiation (the fluorescence emission spectra of photosensitizers have been detected with the excitation wavelength λexc = 405 nm). Insert: Singlet oxygen (1O2) production by Ce6 and Ce6-conjugates; (B) Conjugates receptor-specificity proliferation of K562 sst2+ and WT cells after PDT (5 J.cm−2 light dose with 652 nm irradiation). Different concentrations of conjugates 1 and 2 were incubated with sst2+ and WT cells: (▪) in the absence of unlabeled Octreotide and (□) with Octreotide co-treatment (c = 10−5 M). Test of significance between the group of conjugates phototoxicity in absence and in presence of Octreotide has been performed using Student's test. In case of conjugate 1 value p<0.005 is deemed significant, whereas for conjugate 2 p<0.05; (C) The effect of the sst2 expression on the uptake of conjugate 1, 2 and un-conjugated Ce6. The photosensitizers (c = 1 µM) were incubated with K562 cells in serum-free medium (top) and in the medium with 5% FCS (bottom): (▪) K562 sst2+, (
) K562 WT cells.
doi: https://doi.org/10.1371/journal.pone.0104448.g003