Abstract
Purpose: :
Secreted protein acidic and rich in cisteine (SPARC) has been shown to play an integral role in the progression of numerous malignancies. It is associated with general tissue remodeling and angiogenesis. SPARC expression has been correlated with good prognosis in some cancers and poor prognosis in others. The aim of this study was to determine expression of SPARC in four uveal melanoma cell lines, and one transformed melanocyte cell line. Furthermore, we sought to investigate its role on proliferation and invasion in vitro.
Methods: :
Immunocytochemistry was performed on cytospins of the five cell lines using a monoclonal mouse anti-human antibody to SPARC. Quantitative real-time PCR (Chromo4 thermocycler) was used to demonstrate mRNA levels of SPARC expression in four human uveal melanoma cell lines (92.1, SP6.5, MKT-BR, OCM-1) and one transormed melanocyte cell line (UW-1). SPARC HP genome wide designed siRNA was used (Qiagen) to transfect each of the five cell lines. Flourescently labeled non-silencing control siRNA (Qiagen) was used for detection of transfection efficiency as well used as an appropriate control. Transfected cells were subsequently analyzed using proliferation and invasion assays and compared to appropriate controls.
Results: :
Expression of SPARC at the RNA level was demonstrated using quantitative real-time PCR and confirmed at the protein level by immunocytochemistry for all five cell lines. The cell lines transfected with siRNA directed against SPARC showed a significant decrease in proliferation (p<0.01) when compared to the control groups. Transfected cell lines similarly showed a significant decrease (p<0.01) in invasive ability.
Conclusions: :
SPARC expression appears to be associated with proliferative and invasive capacity of human uveal melanoma cell lines. Targeting this matricellular protein may be one approach to manage malignant progression of uveal melanoma in affected patients.
Keywords: uvea • pathobiology • oncology