Login to Access Video or Poster Abstract: MP44-11
Sources of Funding: 7R01 CA072821-16; 7R01CA176691-03

Introduction

Hyaluronic acid (HA) family of molecules, HA-synthases (HAS-1,2,3), HA-receptors (CD44, RHAMM) and hyaluronidase (HYAL-1) are markers for bladder cancer (BCa) diagnosis and predicting prognosis. HA-family promotes tumor growth and metastasis by inducing epithelial mesenchymal transition (EMT). 4-Methylumbelliferone (4-MU) is an orally bioavailable dietary supplement that inhibits HA synthesis. We evaluated the expression of HA family and EMT markers in bladder tissues and antitumor effects of 4-MU in preclinical models of BCa.

Methods

mRNA expression of HA-family and EMT genes (beta-catenin, Twist, and Snail) in 72 bladder tissue specimens (28 normal; 44 tumor); follow-up: 20.3+/-2.5 months, was measured by QPCR. The effect of 4-MU (0-0.6 mM) on cell growth, apoptosis, HA-signaling were examined in BCa cell lines by Q-PCR, immunoblotting, proximal ligation and PI-3K activity assays. Effect of oral administration of 4-MU (100, 200-mg/kg) on tumor growth was analyzed in preclinical models.

Results

HAS-1, -2 -3, HYAL-1 and Snail levels were 10-20-fold elevated in BCa tissues as compared to normal bladder (P<0.001). In univariate analysis, HAS-1, -2, HYAL-1 and Twist levels correlated with metastasis (P<0.001); HYAL-1 was an independent predictor of metastasis. 4-MU inhibited cell proliferation, chemotactic motility and invasion in a dose-dependent manner; 50-70% inhibition at IC50 (0.4 mM) for HA-synthesis inhibition. 4-MU induced apoptosis (>3-fold) via the death receptor pathway. 4-MU downregulated HA-signaling; mRNA and/or protein levels of CD44, RHAMM, p-Akt, beta-catenin, p-beta-catenin(S552), snail and twist were downregulated by 3-5-fold, but p?catenin((T41/S45), pGSK-3alpha/beta and E-cadherin levels were elevated. 4-MU also inhibited CD44/PI-3K complex formation and PI-3K activity. HA addition or mAkt expression attenuated 4-MU effects. In xenograft studies, 4-MU oral treatment abrogated growth of established HT1376 tumors (vehicle, day 35: 766+/-221 mm3; 4-MU: 128+/-61, day 50). No weight loss or serum or organ toxicity was observed in treated mice.

Conclusions

This study demonstrates that HA-family and signaling is upregulated in BCa and can be specifically targeted for treatment by a non-toxic dietary supplement.

Funding

7R01 CA072821-16; 7R01CA176691-03