Login to Access Video or Poster Abstract: MP48-01
Sources of Funding: Grant NCI/NIH 5R01CA72821; 5R01CA176691

Introduction

Hyaluronidase (HAase) family of enzymes degrades hyaluronic acid (HA). In the human genome there are 6 HAase gens clustered on chromosomes 3p21.3 (HYAL-1, -2, -3) and 7q31.3 (HYAL-4, PH20, HYALP1). HYAL-4 is suspected to be a chondroitinase (Chase), i.e. a chondroitin sulfate-degrading enzyme. To date no study has linked HYAL-4 to any disease or biological activity.

Methods

Q-PCR was performed for measuring the mRNA levels of 6 HAase genes in BCa cell lines, 59 bladder tissues (normal (NBL) = 22; tumor (TBL) = 37) and 160 urine specimens (BCa = 52; normal = 18; history of BCa = 30; benign conditions = 59). A subset of urine specimens was used to measure chase activity using a novel ELISA. By stable transfection of normal urothelial and BCa cells, HYAL-4 function was analyzed in vitro (proliferation, motility, invasion, immunoblotting, Q-PCR assays) and in vivo (s.c. and orthotopic xenograft models).

Results

HYAL1, HYAL4 and HYALP1 mRNA levels were significantly (6-13-fold) elevated in TBL tissues when compared to NBL tissues (P<0.001). In multivariate analysis, in addition to HYAL-1, HYAL-4 was an independent prognosticator of metastasis and death due to BCa (P<0.001). HYAL1, HYAL4 and HYALP1 mRNA levels were also significantly elevated in BCa patients&[prime] urine (P< 0.0001). Chase activity was significantly elevated in BCa patients, as compared to BGU or HXBCa patients (P<0.0001; 100% sensitivity and 84% specificity to detect BCa). Overexpression of HYAL-4 in normal urothelial and BCa cells significantly increased invasion and chemotactic motility (> 3-fold) and enriched a cancer stem cell phenotype-spheroid formation, increased ALDH1 expression and activity, and a cytokeratin 4, 14, 17 molecular signature. HYAL-4 expression up-regulated CD44, MMP-9 and Akt signaling. In s.c. and orthotopic BCa models, HYAL-4 expression increased both tumor growth and metastasis of BCa cells and tumor growth in normal urothelial cells.

Conclusions

This is the first study that links HYAL4 to cancer biology and demonstrates it to be a molecular determinant of BCa.

Funding

Grant NCI/NIH 5R01CA72821; 5R01CA176691