Three-Dimensional Visualization and
Volumetric Analysis of Cancer Therapeutic Agents and Cell Interactions Using Raman Imaging, 10-9110
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Inclusive Dates: 01/01/99 - Current
Background - Every day approximately 1,500
Americans die from cancer, and these deaths are often prolonged and painful. Cancer
therapeutics is a severe challenge to the healthcare industry. Recently, the
implementations of rational drug design, combinatorial chemistry techniques, and high
throughput screening have led to large numbers of new, potential anticancer agents.
However, the mechanisms by which these agents kill tumor cells are unknown.
Approach - The objective of this project is to
develop techniques that would enable the use of Raman microscopic imaging to study the
actions of anticancer drugs at the cellular level. Specifically, a Raman imaging technique
will be developed to study the uptake (amount of the drug taken into the cell),
subcellular localization (specific location at which the drug acts), and characteristics
of local binding (biochemical interaction) of anticancer drugs within the cells.
Anticancer drugs with known cell interactions will be used in this study to evaluate the
feasibility of the Raman imaging technique. Raman image is a chemical image with the
potential to display the spatial distribution of a substance that is invisible in
conventional optical images. This unique characteristic is because the Raman spectra
intrinsically depends upon the structure (vibrational states and chemical bonds) of the
molecules that make up a substance. In this study, two Raman images, tuned at the unique
Raman peaks of the anticancer drug, will be obtained from a cancer cell before and after
the drug treatment. The differences between the two images will show the two-dimensional
distribution of the drug within the cell. A stack of such images representing different
cellular cross sections will be obtained from the Raman microscope for three-dimensional
(3-D) construction. The reconstructed 3-D Raman region indicates the 3-D drug distribution
within the cell. From the drug distribution region, the volume and concentration of the
drug can be estimated. A 3-D visualization program will be developed to display the
locations of the drug within the cell. Knowing the drugs distribution is an
important factor in evaluating its efficacy.
Accomplishments - The Raman microscopic system
was established for imaging the biological samples. Polystyrene microspheres were used to
calibrate the microscopic system. Image-processing algorithms such as Raman image
restoration and enhancement were developed. Raman spectra of both anticancer drugs and
cellular backgrounds were measured. From the spectra, the fingerprint Raman band was
identified. At the drug's unique Raman band, Raman images of a cell were taken. The
illustration shows the Raman images of a breast cancer cell before and after drug
treatment. The high-intensity spots in the Raman image after the drug treatment suggest
the distribution of the drug.
A MDA435 breast cancer cell is shown before
and after drug treatment. The top-left white-light image shows the cell in control. Its
corresponding Raman image at 1002 cm-1 (within the red-box) is illustrated in
the bottom-left image, while the top-right white-light image shows the cell after drug
treatment. Its corresponding Raman image is shown in the bottom-right image.
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