Previous Page  141 / 155 Next Page
Information
Show Menu
Previous Page 141 / 155 Next Page
Page Background

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Poster Abstracts

136 

76-POS

Board 38

Damage of Cancer Cells Evaluated by Intensity Fluctuation of Images under Phase

Contrast Microscope

Morito Sakuma

, Yuichi Kondo, Hideo Higuchi.

The University of Tokyo, Tokyo, Japan.

Selective removal of cancer cell without side effects is necessarily for cancer therapy. Phototoxic

dyes such as IR700 can specifically be delivered to cancer cells, and the cells are damaged by

reactive oxygen species (ROS). But surviving cancer cells damaged by oxidative stress could

obtain resistant to the therapy. Here to understand the effects of phototoxic dyes and detect

resistant cancer cells, we developed a method to measure quantitatively cell damages induced by

ROS of IR700. We evaluated cell damage by calculating the intensity fluctuation of each pixel in

cell images under phase contrast microscopy. We succeeded in quantifying the change in

motility of cell organelles by this method (Sakuma et al. Sci Technol Adv Mater. 2016). IR700

was labeled with the antibody which binds specifically to target cells. IR700-antibody complex

was endocytosed into cultured cells and then cell was photodamaged by illumination of red laser

(650 nm). The degree of cell damage was controlled by adjusting the irradiation time of red laser.

The motility of cell organelles detected by the intensity fluctuation method decreased gradually

with a progression of cell damage. To elucidate the mechanisms of decrease in the organelles

motility, we analyzed the effects of photoactivation of IR700 on activities of organelles and

motor proteins. Lysosomes containing IR700 in cells were damaged quickly by the

photoactivation of IR700 and the contents in lysosomes were diffused out into cytoplasm. The

contents diffused from lysosomes caused the dysfunction of transporter kinesin and

mitochondria. Therefore, these damages of organelles and motors may be a primary factor for

causing decrease of organelles motility. These results suggested that the cell organelles motility

is a primary indicator of cell viability.