7. Project Summary/Abstract
Cancer metastases are responsible for most deaths from the disease. However, most current cancer therapies
are anti-proliferative, rather than anti-metastatic. Challenges to the clinical realization of anti-metastatic
therapies include dose-limiting toxicity to non-cancer cells, effective targeting, effective timing of administration
given that metastasis is an early cancer process, and effectiveness in the face of adaptive invasion strategies
by cancer cells. An ideal platform to test anti-metastatic therapeutic candidates would mimic the tumor
microenvironment, and accurately assess cancer cell motile phenotypes as well as pro-invasion microstructural
signatures in the extracellular matrix.
This proposal aims to 1) develop a dual-modality quantitative phase and polarized light microscopy system
capable of 2) evaluating the effects of inhibitors of matrix invasion and microenvironmental factors on the
spread of cancer cells in a tissue-like in vitro environment. Quantitative optical indices from the proposed
system accurately assess cell phenotype and microstructural signatures of invasion, by evaluating cell phase
and matrix birefringence signals. These imaging modalities also deliver low optical power to the sample,
allowing for long-term, serial microscopy without phototoxic effects on cancer cell movement. Finally, an
innovative but simple culture set-up creates collagen networks with alignment and pre-stress similar to the
tumor microenvironment. Steps to achieve these aims include addition of polarizing optics to an existing digital
holographic microscope, signal calibration, channel co-registration, and initial time-lapse imaging of an in vitro
3D model of cancer invasion. Optical indices of invasion will be evaluated in a scaled-up study.
After installing a second camera and full polarization state generator and analyzer on the existing digital
holographic microscope, phase and birefringence signals will be evaluated and co-registered using a
polystyrene microsphere standard (n=1.59) set in solid mounting media (n=1.52). Phase and polarized light
parameters will be calibrated by computing phase maps of standard beads of fixed diameter, and optical
retardance of a zero-order waveplate. The invasion of the breast cancer cell line MDA-MB-231 will be
evaluated from serial time-lapse imaging over 24 hours, in the presence and absence of 30 nM chondramide,
an actin-stabilizing anti-metastatic therapeutic candidate. The effects of pre-stress and extracellular matrix
alignment will also be evaluated.
The health-relatedness of this proposal lies in development of a quantitative phase and polarized light
microscope that computes parameter maps for invading cancer cells and their microenvironmental
surroundings. The proposed microscope reduces phototoxicity and provides quantitative metrics for accurate
assessment of the mechanisms and aggressiveness of cancer cell invasion, thus enabling testing of anti-
metastatic drug candidates.