engleski

Altered cell-cell adhesion and cytoskeleton properties in a cisplatin resistant human larygeal carcinoma cell line

Cisplatin is a widely used chemotherapeutic agent generally recognized as a DNA-damaging drug, although only 1% of intracellular cisplatin reacts with DNA. An apoptotic pathway induced by cisplatin independently of its DNA-damaging activity has been identified. Since it has been shown that cisplatin reacts with components of cell membrane and cytoskeleton, we compared the properties of cell-cell adhesion structures and cytoskeleton between cisplatin resistant CA3ST and parental human laryngeal carcinoma HEp2 cell line. Western blot revealed no change in the expression of intercellular adhesion components N-cadherin, plakoglobin, desmoglein, p120 catenin and vinculin. However, beta-catenin was strongly up-regulated in CA3ST cells, independently of cell density. Confocal microscopy confirmed the up-regulation of beta-catenin in CA3ST cells, where it produced a punctuate immunofluorescence staining at the cell borders, while no staining could be detected at the membranes of parental cells. RT-PCR analysis detected equal amounts of beta-catenin transcript in both cell lines, suggesting that its increased expression in CA3ST cells is regulated on a posttranscriptional level. Since three additionally analyzed cisplatin resistant cell lines also showed up-regulation of beta-catenin expression, we speculate that this could be a general phenomena accompanying cisplatin resistance. While phalloidin staining revealed mainly cortical actin filaments in HEp2 cells, numerous stress fibers were characteristic of CA3ST cells. Treatment of HEp2 cells with cisplatin induced formation of stress fibers, to a degree similar to the one observed in CA3ST cells. In addition, microtubular structures were also altered in CA3ST cells. The presented data indicate that cisplatin treatment alters beta-catenin expression and cytoskeleton organization in the human laryngeal carcinoma cell line.

cisplatin; cell adhezion; cytoskeleton; drug-resistance; tumor cells

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