Gene expression profile of circulating CD34(+) cells and granulocytes in chronic myeloid leukemia.

Purpose: We compared the gene expression profile of peripheral blood CD34(+) cells and granulocytes in subjects with chronic myeloid leukemia (CML), with the accent on signaling pathways affected by BCR-ABL oncogene.

Methods: The microarray analyses have been performed in circulating CD34(+) cells and granulocytes from peripheral blood of 7 subjects with CML and 7 healthy donors. All studied BCR-ABL positive CML patients were in chronic phase, with a mean value of 2012±SD of CD34(+)cells/μl in peripheral blood.

Results: The gene expression profile was more prominent in CML CD34(+) cells (3553 genes) compared to granulocytes (2701 genes). The 41 and 39 genes were significantly upregulated in CML CD34(+) cells (HINT1, TXN, SERBP1) and granulocytes, respectively. BCR-ABL oncogene activated PI3K/AKT and MAPK signaling through significant upregulation of PTPN11, CDK4/6, and MYC and reduction of E2F1, KRAS, and NFKBIA gene expression in CD34(+) cells. Among genes linked to the inhibition of cellular proliferation by BCR-ABL inhibitor Imatinib, the FOS and STAT1 demonstrated significantly decreased expression in CML.

Conclusion: The presence of BCR-ABL fusion gene doubled the expression quantity of genes involved in the regulation of cell cycle, proliferation and apoptosis of CD34(+) cells. These results determined the modified genes in PI3K/AKT and MAPK signaling of CML subjects.