Analysis of the Expression of PHTF1 and Related Genes in Acute Lymphoblastic Leukemia

Background: In the human T-cell acute lymphoblastic leukemia (T-ALL) cell line Molt-4, siRNA-mediated suppression of BCL11B expression was shown to inhibit proliferation and induce apoptosis, which may be related to PHTF1 gene expression, and the FEM1B and Apaf-1 genes may be downstream of PHTF1. In this study, we analyzed the expression level of PHTF1 and related genes in patients with ALL to clarify the role of the PHTF1-FEM1b-Apaf-1 pathway in hematologic malignancies.

Methods: Fifteen newly diagnosed and untreated patients with AML, fourteen newly diagnosed and untreated patients with CML in chronic phase, twenty-two newly diagnosed and untreated patients with ALL, and six newly diagnosed and untreated patients with CLL were recruited. Peripheral blood mononuclear cells (PBMCs) from ten healthy individuals (HIs) served as controls. PBMCs were separated using the Ficoll-Hypaque gradient centrifugation method. All procedures were conducted in accordance with the guidelines of the Medical Ethics committees of the Health Bureau of Guangdong Province, China.Real-time PCR was used to determine the gene expression level of PHTF1 in hematologic malignancies. The PHTF1, BCL11B, FEM1B and Apaf-1 gene expression levels and correlations were analyzed in patients with primary ALL and healthy individuals (HIs).

Results: PHTF1 overexpression was found in recently diagnosed AML (p <0.001), CML-CP (p<0.001), and ALL (p= 0.016) patients in comparison with HIs. The PHTF1 expression level in CLL patients was not significantly different compared with HIs (p= 0.165). FEM1b and Apaf-1 overexpression was found in recently diagnosed ALL (p<0.005) patients compared with HIs. Positively correlated expression was found for the PHTF1, FEM1b and Apaf-1 genes in patients with ALL (p<0.005) and HIs (p<0.005), and positively correlated expression was found for the PHTF1 and BCL11B genes in HIs (p<0.005).

Conclusions: PHTF1 acts as a tumor suppressor gene, and its overexpression might be related to cell proliferation, inhibition and apoptosis. PHTF1 and BCL11B gene disorders may contribute to T-ALL pathogenesis. PHTF1 might be a therapeutic target for triggering the PHTF1-FEM1b-Apaf-1 apoptosis pathway in primary acute lymphoblastic leukemia.

Acknowledgment

The project was sponsored by grants from National Natural Science Foundation of China (No. 81100384, No. 81270648, No.91129720, and No. 30771980)