Breast cancer is the fourth leading cause of fatal disease in Taiwanese women (2008).The occurrence rate was increased from 9.4% to 13.5% per 100,000 cases during 1998-2008. In Taiwan, the young age early onset patients have been diagnosed around 30-50 years. In this early onset populations, there are still a major part (around 40-50%) of cases was first diagnosed as lympho-node positive metastasis although the advanced diagnosis technology was used. Such results indicated that early diagnosis with a convinced molecular marker is critical for breast cancer prevention. Hyaluronan is a strand like glycosaminoglycan as a component of the extracellular matrix (ECM). It is important for the cancer cells migration, proliferation, and differentiation process. Hyaluronan is synthesized by three types of enzymes (hyaluronan synthase, HA). However, in our preliminary data, the type III HA should be the most important role in the breast cancer formation: 1. we demonstrated that overexpression of the HAS3 was detected in the adjacent-tumor normal tissue when compared to tumor tissues (n=500). 2. Increased expression of the HAS3 was detected in breast cancer cells under low-serum status. Such results were similar to some tumor suppressor proteins (such as p21/WAF1) observed in breast cancer cells. 3. Increased cell proliferation rate was detected in the HAS3-SiRNA knocked down breast cancer cells. All these results proposed the antitumor effects of HAS3 gene expression in the tumor surrounded ECM. This 3-year proposal is comprised of the following aims: Year-1 study : To explore the molecular mechanisms of HAS3-mediated antitumor effects in Taiwanese breast tumor tissues. Aim-1: Study the effects of HAS3 gene over expression in human breast cancer cells. Clinical samples of advanced stage tumor tissues will be collected. A molecular epidemiology study of selected family history will be conducted to study the association of the triple negativity and HAS3 expression. Evaluation on the biological function of HAS3 overexpression in the advanced-stage breast cancer cells model experiments: tet-on expression system will be established. Aim-2: Study the effects of HAS3 gene inhibition (knock-out) in normal fibroblast cells. Establish the HASE/BRCA1 conditional double-knocked-out mice model to evaluate the antitumor effects of HAS3 and their synergistic effects with BRCA-1 gene interactions. Inhibit the gene expression by SiRNA technique to study the invitro antitumor mechanisms of HAS3 gene in human breast fibroblast cells. Aim-3: Study the mechanisms of HAS3 gene expression affects on the cell growth, death, metastasis, invasion, and cancer microenvironments. Establish the gene overexpression and inhibition systems in human breast cancer cells and observe the mechanisms of HAS3-mediated anti-carcinogenic roles. Year-2 study : To explore the molecular mechanisms of HAS3-mediated antitumor effects in the in-vitro cell model system Aim-1: Study the mechanisms of tumor microenvironment affects on the breast cancer cell's HAS3 gene expression. Exhaust the culture environment (low serum, oxygen.. et al.) to induce the HAS3 gene expression in human cancer cells. Establish the primary cultured tumor-margined fibroblast (TMF) cells bank and observe the interaction of breast cancer cell lines and the TMFs isolated from different types of breast cancer patients. Aim-2: Study the antitumor-activities of tumor microenvironment-induced breast cancer cell's HAS3 gene expression. Manipulate the HAS3 gene by either tet-on overexpression and SiRNA inhibition to observe the TMF cells affects on the breast cancers migration and metastasis. Evaluate the HAS3 gene expression affects on the drug-resistances of triple negative tumor cells.
|Effective start/end date||8/1/14 → 7/31/15|
- hyaluronan synthase-3
- breast cancer