Characterization of differential expression patterns of the extracellular purinergic enzymes in colorectal cancer

Objective: The aim of this study is to characterize tumor cell specific expression of purinergic ecto-enzymes CD39 and CD73 and to associate prognostic significance of these expression patterns in colorectal cancer (CRC) patients. Methods: Gene expression of the target genes in various CRC cell lines were assessed via WB and RT-PCR. Additionally, tumor vs stromal cell expression of the target genes was analyzed from publicly available patient expression datasets. Finally, the correlation between CD39 and CD73 expression with patient prognosis was analyzed via TCGA datasets. Results: In CRC cell lines CD39 found to be not expressed at all while CD73 was expressed extensively in most cell lines via WB and RT-CR analyses. Patient microarray expression data confirmed the results from CRC cells lines that CD39 expression was very low in epithelial/tumor cells relative to other stromal cell types yet CD73 was expressed abundantly in every cell type within patient tumor samples. Interestingly, CD39 expression in patient tumors was correlated with favorable prognosis while CD73 expression was associated with worse prognosis. Conclusion: Although CD39 and CD73 are related enzymes involved in extracellular purinergic signaling, their expression patterns in tumor cells and prognostic effects in patients show opposing outcomes. Therefore, better insights in understanding the functional involvement of purinergic ecto-enzymes in colorectal tumor development is needed via further mechanistical studies.