Paclitaxel-hyaluronan hydrosoluble bioconjugate: Mechanism of action in human bladder cancer cell lines

Isabella Monia Montagner, Alessandra Banzato, Gaia Zuccolotto, Davide Renier, Monica Campisi, PierFrancesco Bassi, Paola Zanovello, Antonio Rosato

Research output: Contribution to journalArticle

Abstract

Objectives: A previously described hydrosoluble paclitaxel-hyaluronan bioconjugate appears particularly well suited for treatment of superficial bladder cancer because of its in vitro cytotoxic profile against urothelial carcinoma (UC) cell lines and in vivo biocompatibility. The aim of this work was to assess the mechanism of action of the bioconjugate in UC cells. Materials and methods: Expression of CD44 and RHAMM hyaluronan-binding receptors in RT-4 and RT-112/84 UC cell lines, interaction of fluorochrome-labeled bioconjugate with tumor cells, CD44 modulation upon incubation with the compound or free hyaluronan, and caspase activation were assessed by flow cytometry. Cytotoxicity was studied by the MTT assay. Analysis of bioconjugate intracellular localization and effects on β-tubulin organization was carried out by confocal microscopy. Results: The paclitaxel-hyaluronan bioconjugate bound to UC tumor cells entered intracellular compartments through a saturable and energy-dependent mechanism that involved CD44, as assessed by blocking with specific antibody. Upon internalization, the bioconjugate accumulated into lysosomes where the esteric bond between paclitaxel and the hyaluronan moiety was cleaved, leading to cytoplasmic diffusion of the free drug, caspase activation, and disruption of the β-tubulin microtubular mesh with subsequent cell death. Conclusions: Conjugation of paclitaxel to hyaluronan results in a new chemical entity, characterized by selective targeting to polymer receptors on plasma membrane and cell entry through receptor-mediated endocytosis, followed by lysosomal accumulation. Ultimately, the active molecule is released, fully preserving the cytotoxic potential and profile of clinically used free paclitaxel.

Original languageEnglish
Pages (from-to)1261-1269
Number of pages9
JournalUrologic Oncology: Seminars and Original Investigations
Volume31
Issue number7
DOIs
Publication statusPublished - Oct 2013

Keywords

  • Bioconjugate
  • Bladder cancer
  • Hyaluronan
  • Paclitaxel

ASJC Scopus subject areas

  • Oncology
  • Urology

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