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Holographic view of the senescent cells: Imagine all the senescent cells are not flattened
Author(s) -
Şimay Yaprak Dilber,
Özdemir Aysun,
Ibisoglu Burçin,
Ark Mustafa
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.934.9
Subject(s) - holography , microbiology and biotechnology , biology , optics , physics
Senescence is the process by which cells arrest from cell cycle and lose their ability to divide at the end of replicative life span. This type of senescence is called “replicative senescence”. Senescence can also be induced prematurely by chemotherapeutic drugs, oxidative stres, overexpression of active oncogenes and unrepaired DNA damage. It is accepted that senescent cells show morphologically flattened, enlarged and irregular cell shapes. However, it is not well elucidated how these morphological alterations occur and whether these alterations are different due to the type of senescence‐inducing agent in drug‐induced senescence. In the current study we evaluated area, volume, membrane irregularity, and maximum, average and cytoplasmic thickness in doxorubicin and ouabain‐induced senescent cells using 3D holographic microscopy. Treatment of doxorubicin (300 nM, 72h) and ouabain (30 nM, 72h) resulted in a significant increase in β‐galactosidase positive cells indicating that both doxorubicin and ouabain induced senescence in HeLa cells. The phase contrast microscopy images showed that doxorubicin and ouabain induced an increase in cell area and multinuclearity in senescent cells. A significant increase in total protein content per cell, one of the hallmark of senescence, was also determined in senescent HeLa cells. In consistent with the phase contrast microscopy findings, 3D holographic microscopy results showed that doxorubicin and ouabain increased the area and the volume in senescent HeLa cells. On the other hand, maximum thickness was significantly enhanced in senescent cells and there was no change in the average and the cytoplasmic thickness. Moreover, we were not able to detect any difference in membrane irregularity, thought to be increased in senescence, between control and senescent HeLa cells. Our results demonstrated that senescent cells that appear to be flattened considering the data of phase contrast microscopy, actually show enlarged cell shape without flattening. Because the enhanced cell area and volume were accompanied by the increased total protein content per cell, the senescent cells might not be flattened. Support or Funding Information This work was supported by TUBITAK in 215S998 and 110S426 projects.Holographic images of the senescent HeLa cells.