Unlocking the ultrastructure of colorectal cancer cells in vitro using selective staining.
OBJECTIVE
To characterise differences between three widely used colorectal cancer cell lines using ultrastructural selective staining for glycogen to determine variation in metastatic properties.


METHODS
Transmission electron microscopy was used in this investigation to help identify intracellular structures and morphological features which are precursors of tumor invasion. In addition to morphological markers, we used selective staining of glycogen as a marker for neoplastic cellular proliferation and determined whether levels of glycogen change between the three different cell lines.


RESULTS
Ultrastructural analysis revealed morphological differences between the cell lines, as well as differentiation into two sub-populations within each cell line. Caco-2 cells contained large glycogen deposits as well as showing the most obvious morphological changes between the two sub-populations. SW480 cells also contained large glycogen stores as well as deep cellular protrusions when grown on porous filter membranes. HT-29 cells had trace amounts of glycogen stores with few cellular projections into the filter pores and no tight junction formation.


CONCLUSIONS
Morphology indicative of metastatic properties coincided with larger glycogen deposits, providing strong evidence for the use of selective staining to determine the neoplastic properties of cells.
Australian Key Centre for Microscopy and Microanalysis, Madsen Building F09, The University of Sydney, NSW 2006, Australia. j.biazik@usyd.edu.au
Joanna M
JM
Biazik
Kristina A
KA
Jahn
Yingying
Y
Su
Ya-Na
YN
Wu
Filip
F
Braet
D018938:Caco-2 Cells / Q000737:chemistry / Q000648:ultrastructure*; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000473:pathology*; D006003:Glycogen / Q000032:analysis; D019073:HT29 Cells / Q000737:chemistry / Q000648:ultrastructure*; D006801:Humans; D046529:Microscopy, Electron, Transmission / Q000379:methods; D013194:Staining and Labeling / Q000379:methods*
D006003:Glycogen