title: Patterning of endocytic vesicles and its control by voltage-gated Na+ channel activity in rat prostate cancer cells: fractal analyses.
abstract: Fractal methods were used to analyze quantitative differences in secretory membrane activities of two rat prostate cancer cell lines (Mat-LyLu and AT-2) of strong and weak metastatic potential, respectively. Each cell's endocytic activity was determined by horseradish peroxidase uptake. Digital images of the patterns of vesicular staining were evaluated by multifractal analyses: generalized fractal dimension (Dq) and its Legendre transform f(alpha), as well as partitioned iterated function system -- semifractal (PIFS-SF) analysis. These approaches revealed consistently that, under control conditions, all multifractal parameters and PIFS-SF codes determined had values greater for Mat-LyLu compared with AT-2 cells. This would agree generally with the endocytic/vesicular activity of the strongly metastatic Mat-LyLu cells being more developed than the corresponding weakly metastatic AT-2 cells. All the parameters studied were sensitive to tetrodotoxin (TTX) pre-treatment of the cells, which blocked voltage-gated Na+ channels (VGSCs). Some of the parameters had a "simple" dependence on VGSC activity, whereby pre-treatment with TTX reduced the values for the MAT-LyLu cells and eliminated the differences between the two cell lines. For other parameters, however, there was a "complex" dependence on VGSC activity. The possible physical/physiological meaning of the mathematical parameters studied and the nature of involvement of VGSC activity in control of endocytosis/secretion are discussed.
authors.affiliation: Neuroscience Solutions to Cancer Research Group, Department of Biological Sciences, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London, SW7 2AZ, UK.
authors.forename: Monika
authors.initials: M
authors.lastname: Krasowska
authors.forename: Zbigniew J
authors.initials: ZJ
authors.lastname: Grzywna
authors.forename: Maria E
authors.initials: ME
authors.lastname: Mycielska
authors.forename: Mustafa B A
authors.initials: MB
authors.lastname: Djamgoz
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003198:Computer Simulation; D017709:Fractals; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008954:Models, Biological; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D022161:Transport Vesicles / Q000378:metabolism* / Q000473:pathology*
chemical_list: D015222:Sodium Channels; D013779:Tetrodotoxin