Expression of hyaluronan synthases (HAS1-3) and hyaluronidases (HYAL1-2) in serous ovarian carcinomas: inverse correlation between HYAL1 and hyaluronan content.
BACKGROUND
Hyaluronan, a tumor promoting extracellular matrix polysaccharide, is elevated in malignant epithelial ovarian tumors, and associates with an unfavorable prognosis. To explore possible contributors to the accumulation of hyaluronan, we examined the expression of hyaluronan synthases (HAS1, HAS2 and HAS3) and hyaluronidases (HYAL1 and HYAL2), correlated with hyaluronidase enzyme activity hyaluronan content and HAS1-3 immunoreactivity.


METHODS
Normal ovaries (n = 5) and 34 serous epithelial ovarian tumors, divided into 4 groups: malignant grades 1+2 (n = 10); malignant grade 3 (n = 10); borderline (n = 4) and benign epithelial tumors (n = 10), were analyzed for mRNA by real-time RT-PCR and compared to hyaluronidase activity, hyaluronan staining, and HAS1-3 immunoreactivity in tissue sections of the same specimens.


RESULTS
The levels of HAS2 and HAS3 mRNA (HAS1 was low or absent), were not consistently increased in the carcinomas, and were not significantly correlated with HAS protein or hyaluronan accumulation in individual samples. Instead, the median of HYAL1 mRNA level was 69% lower in grade 3 serous ovarian cancers compared to normal ovaries (P = 0.01). The expression of HYAL1, but not HYAL2, significantly correlated with the enzymatic activity of tissue hyaluronidases (r = 0.5; P = 0.006). An inverse correlation was noted between HYAL1 mRNA and the intensity of hyaluronan staining of the corresponding tissue sections (r = -0.4; P = 0.025).


CONCLUSIONS
The results indicate that in serous epithelial ovarian malignancies HAS expression is not consistently elevated but HYAL1 expression is significantly reduced and correlates with the accumulation of hyaluronan. (233 words).
Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Kuopio and Kuopio University Hospital, Kuopio, Finland. nykopp@hytti.uku.fi
Timo K
TK
Nykopp
Kirsi
K
Rilla
Reijo
R
Sironen
Markku I
MI
Tammi
Raija H
RH
Tammi
Kirsi
K
Hämäläinen
Anna-Mari
AM
Heikkinen
Marja
M
Komulainen
Veli-Matti
VM
Kosma
Maarit
M
Anttila
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D014453:Glucuronosyltransferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000378:metabolism*; D006821:Hyaluronoglucosaminidase / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D055815:Young Adult
D006820:Hyaluronic Acid; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D006821:Hyaluronoglucosaminidase