Abstract
Purpose: :
Recently, increasing evidence told cancer stem cells expressing embryonic and neuronal stem cell markers in human retinoblastoma (Rb). This study was conducted to determine whether stem-like cancer cells (SLCCs) in Rb express retinal stem cell-related genes and whether SLCCs can directly differentiate into retinal neuron-like cells.
Methods: :
The characteristics of WERI-Rb1cancer stem cells were determined by Hoechst 33342 staining, clone formation assay and CD133 flow cytometry. The expression of embryonic stem cell and retinal stem cell-related genes and protein was analyzed by real-time PCR and immunofluorescence. The SLCCs were restrictly differentiated into retinal neuron-like cells by Wnt and Nodal antagonists Dkk-1 and Lefty-A.
Results: :
A small persistent population of cells (0.075±0.017%) excluding Hoechst dye exhibited a cancer stem cell-like phenotype in a verapamil-sensitive manner. The SLCCs displayed highly clonogenic ability and increased CD133 expression with isolation and expansion in culture in serum-free medium. By comparing the quality of expression of stem cell markers, Oct3/4 was more highly expressed (4.74±0.37-fold) in the SLCCs than in human embryonic stem cells. Owning to the properties of intrinsic retinal stem cell-related gene expression, the SLCCs can be induced into neuron-like cells expressing GFAP and Rhodopsin.
Conclusions: :
SLCCs from the WERI-Rb1 line expressed embryonic stem cell- and retinal stem cell-related genes, and then further induced into retinal neurons. These preliminary findings provide new insight into cancer stem cells and SLCCs in Rb might be a tool for potential cell replacement therapy of retinal degeneration diseases.