The effect of mitochondria-targeted antioxidants
on normal and transformed cells in culture
E.V. Titova, O.Y. Ivanova, E.N. Popova, O.Y. Pletjushkina, V.B. Dugina, V.P. Skulachev
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University
The reorganization of actin microfilaments plays a crucial role in oncogenic transformation and
leads to distortion of cell polarization and motility. One of possible explanation of actin network
system disorders is activation of oncogenic signaling pathways which determine cell polarization,
directional motility and substrate adhesion by changing in gene expression of actin binding
proteins such as myosin, gelsolin, tropomyosin. In this study we investigated the effect of
antioxidants specifically addressed to mitochondria (SkQ1 and their analogs) on normal
(MRC5) and transformed (MRC5-V1 and MRC5-V2) human pulmonary fibroblasts and
on human fibrosarcoma HT1080 cells.
We have detected an important cell shape alteration during incubation of normal and transformed
fibroblasts with mitochondria-targeted antioxidants (20-40 nM from 5 hours to 3-7 days): cells
became highly spread, actin microfilaments bundles were formed. We have evaluated
immunomorphologically that SkQ1 and their analogs led to formation of thick and parallel
actin bundles (stress fibers containing beta actin, myosin II, alpha actinin, gelsolin, alpha
smooth muscle actin) in MRC5-V1 and MRC5-V2 cultures. The effect of N-acetyl-cysteine
(NAC) and Trolox on MRC5-V1 was similar to SkQ1, but working concentrations of this
antioxidants were much higher: 5mM for NAC and 100μM for Trolox. Phenotype reversion
by SkQ1 treatment was observed also with human fibrosarcoma HT1080 cell line.
We have revealed immunomorphologically and morphometrically that mitochondria-targeted
antioxidants led to focal adhesion (FA) elongation and further reorganization with forming of
mature FAs in transformed fibroblasts. Western blot analysis showed the increase of FA
protein vinculin in MRC5-V1 after mitochondria-targeted antioxidants (20-40 nM, 7 days),
NAC (5 mM, 7 days) and trolox (100 μM, 7 days) incubation.
We have showed the effect of SkQR1 on human fibrosarcoma cells proliferation. SkQR1
treatment (20 nM, 24 h) led to mitotic-entry delay in HT1080 cells after 18 h of
serum stimulation.
Mitochondria-targeted antioxidants induced phenotypic reversion in our experimental model.
The results of our present work are in concerning with the effect of antioxidants on
ras-transformed cells investigated earlier (Alexandrova et. al, 2006; Popova et al., 2006).
Homo Sapiens Liberatus Workshop, Moscow State University, May 2010