Meditech IDs new breast cancer target

Victorian cancer biopharma Meditech Research (ASX:MTR) claims to have identified a hot new target for breast cancer therapy -- an enzyme called hyaluronic synthase 2 (HAS2), found in vesicles in cell membranes.

Assoc Prof Tracey Brown's research team at the Monash University's Hyaluronan Research Laboratory has shown that antisense suppression of the HAS2 gene not only completely inhibits the initiation of breast adenocarcinomas in vitro, and in mouse models of breast cancer, it also prevents existing breast cancers metastasising.

"We think it's pretty neat that it does both," Brown said.

Brown's team has published its discovery in the latest edition of Cancer Research, the journal of the American Association for Cancer Research.

Brown said HAS2 is a cell-membrane protein that is involved in the biosynthesis of hyaluronic acid, which has a key role in tumour growth and progression.

Breast cancers and other adenocarcinomas, including prostate cancer, over-express hyaluronic acid, as a consequence of over-expression of HAS2 on the cell membrane. "There's a direct correlation between over-expression of HAS2 and the invasiveness of breast cancer, " Brown said.

"Hyaluronic acid causes breast cancers to absorb water and swell, creating gaps between cells through which new tumour cells can escape -- there are very high concentrations of hyaluronic acid at the edges of tumours."

Brown said HAS2 is closely related to enzymes that break down hyaluronic acid -- the membrane vesicles contain the cellular machinery for synthesising and degrading HA. The HA degradation process creates small residues that promote angiogenesis in tumours.

Brown said that the identification of the new protein target could lead to the development of new therapeutics, based on antibodies to HAS2, or small-molecule drugs to block HA synthesis.