Expression of pig7 gene in acute leukemia and its potential to modulate the chemosensitivity of leukemic cells

We analyzed expression of p53-induced gene 7 (pig7), at the transcript level, in bone marrow samples from patients with de novo acute leukemia (AL) and normal controls by quantitative reverse transcription PCR (RT-PCR), and revealed a markedly decreased pig7 expression in the patient group, as well as in the relapsed/refractory patients compared with those at initial diagnosis. By endonuclease analysis, we detected only one form of pig7 transcript, i.e., small integral membrane protein of late endosome (simple), in AL patients. In addition, up-regulated pig7 expression could be detected in differentiated leukemic cells induced by drugs. Transient expression of pig7 in leukemic cells exhibited no evident effect on cell proliferation and differentiation, but could intensify inhibitory efficacy of etoposide (VP16) and daunorubicin (DNR). Conclusively, the present study provides the evidence that pig7 is a silenced gene affected by perturbed differentiation in acute leukemia and restoration of pig7 expression sensitizes leukemic cells to chemotherapeutic agents.