This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Golshani, R. Articles by Lokeshwar, V. B. Search for Related Content PubMed PubMed Citation Articles by Golshani, R. Articles by Lokeshwar, V. B.

Hyaluronic Acid Synthase-1 Expression Regulates Bladder Cancer Growth, Invasion, and Angiogenesis through CD44

Departments of ¹ Cell Biology and Anatomy and ² Urology and ³ Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida

Requests for reprints: Vinata B. Lokeshwar, Department of Urology (M-800), Miller School of Medicine, University of Miami, P. O. Box 016960, Miami, FL 33101. Phone: 305-243-6321; Fax: 305-243-6893; E-mail: vlokeshw{at}med.miami.edu.

Hyaluronic acid (HA) promotes tumor metastasis and is an accurate diagnostic marker for bladder cancer. HA is synthesized by HA synthases HAS1, HAS2, or HAS3. We have previously shown that HAS1 expression in tumor tissues is a predictor of bladder cancer recurrence and treatment failure. In this study, we stably transfected HT1376 bladder cancer cells with HAS1-sense (HAS1-S), HAS1-antisense (HAS1-AS), or vector cDNA constructs. Whereas HAS1-S transfectants produced 1.7-fold more HA than vector transfectants, HA production was reduced by 70% in HAS1-AS transfectants. HAS1-AS transfectants grew 5-fold slower and were 60% less invasive than vector and HAS1-S transfectants. HAS1-AS transfectants were blocked in G₂-M phase of the cell cycle due to down-regulation of cyclin B1, cdc25c, and cyclin-dependent kinase 1 levels. These transfectants were also 5- to 10-fold more apoptotic due to the activation of the Fas-Fas ligand–mediated extrinsic pathway. HAS1-AS transfectants showed a 4-fold decrease in ErbB2 phosphorylation and down-regulation of CD44 variant isoforms (CD44-v3, CD44-v6, and CD44-E) both at the protein and mRNA levels. However, no decrease in RHAMM levels was observed. The decrease in CD44-v mRNA levels was not due to increased mRNA degradation. Whereas CD44 small interfering RNA (siRNA) transfection decreased cell growth and induced apoptosis in HT1376 cells, HA addition modestly increased CD44 expression and cell growth in HAS1-AS transfectants, which could be blocked by CD44 siRNA. In xenograft studies, HAS1-AS tumors grew 3- to 5-fold slower and had 4-fold lower microvessel density. These results show that HAS1 regulates bladder cancer growth and progression by modulating HA synthesis and HA receptor levels. [Cancer Res 2008;68(2):483–91]