G-CSF upregulates the expression of aquaporin-9 through CEBPB to enhance the cytotoxic activity of arsenic trioxide to acute myeloid leukemia cells

Abstract

Background Arsenic trioxide (ATO) is highly effective in acute promyelocytic leukemia (APL) patients, but it fails to show satisfactory efficacy in other acute myeloid leukemia (AML) patients with non-APL subtypes. Different from the APL cells, most non-APL AML cells express low levels of the ATO transporter Aquaporin-9 (AQP9) protein, making them less sensitive to ATO treatment. Recently, we found that granulocyte colony stimulating factor (G-CSF) can upregulate the expression of AQP9. We hypothesized that the pretreatment with G-CSF may enhance the antitumor effect of ATO in non-APL AML cells. In addition, we aimed to elucidate the underlying mechanisms by which G-CSF upregulates the expression of AQP9. Methods Non-APL AML cell lines including THP-1 and HL-60 were pretreated with or without G-CSF (100 ng/ml) for 24 h, followed by the treatment with ATO (2 μM) for 48 h. Cell morphology was observed under the microscope after Wright-Giemsa staining. Flow cytometry was performed to evaluate the cell apoptosis levels. The intracellular concentrations of ATO were determined by atomic fluorescence spectrometry. The mRNA and protein expression were respectively measured by quantitative reverse transcription PCR (RT-qPCR) and western blotting. Target genes were knocked down by transfection with small interfering RNA (siRNA), or overexpressed by transfection with overexpression plasmids. The cell line derived xenograft mouse model was established to confirm the results of the in vitro experiments. Results Compared with using ATO alone, the combination of G-CSF with ATO induced the cell apoptosis more dramatically. G-CSF upregulated the expression of AQP9 and enhanced the intracellular concentrations of ATO in AML cells. When AQP9 was overexpressed, it markedly enhanced the cytotoxic activity of ATO. On the other hand, when AQP9 was knocked down, it profoundly attenuated the combinational effect. Moreover, we found that the upregulation of AQP9 by G-CSF depends on the transcription factor CCAAT enhancer binding protein beta (CEBPB). We also demonstrated that the combination of G-CSF and ATO significantly inhibited tumor growth in the xenograft mouse model. Conclusions The combination of G-CSF and ATO may be a potential therapeutic strategy for AML patients.

Assessing the double‐edged of extracellular signal‐regulated kinase/CCAAT‐enhancer‐binding protein beta signaling pathway in arsenic‐induced skin damage and its potential foodborne interventions

“…38 Previous studies [39][40][41] have primarily focused on the critical role of CEBPB in cellular senescence. However, several studies [42][43][44] have also observed an association between CEBPB and pro-apoptotic processes. In our study, we demonstrated that high-dose short-term arsenic exposure up-regulates the expression of CEBPB, promoting cell apoptosis.…”

“…In vitro study 44 have found that CEBPB is involved in arsenic trioxide‐induced endoplasmic reticulum stress‐mediated apoptosis. In addition, a recent study 43 discovered that granulocyte colony‐stimulating factor up‐regulates the expression of aquaporin‐9 through CEBPB, enhancing the pro‐apoptotic ability of arsenic trioxide in acute myeloid leukemia cells. These studies provide further evidence supporting the crucial role of CEBPB in arsenic‐induced apoptosis.…”

Critical Role of Aquaporins in Cancer: Focus on Hematological Malignancies

“…In fact, the greater part of non-APL AML cells presents small concentrations of the ATO transporter AQP9 protein, making them less responsive to ATO administration. Lately, an experiment showed that granulocyte-colony stimulating factor (G-CSF) can increase the expression of AQP9 [ 81 ]. The authors supposed that the administration of G-CSF may foster the antileukemic action of ATO in non-APL AML cells.…”

“…Moreover, an experiment demonstrated that the increase in AQP9 by G-CSF is due to the transcription factor CCAAT enhancer binding protein beta (CEBPB). Interestingly, the study reported that the combined use of G-CSF and ATO remarkably reduced tumor proliferation in a xenograft animal model [ 81 ]. Therefore, the combined employment of G-CSF and ATO increasing AQP9 concentrations would be a possible therapeutic option for AML subjects.…”

Arsenic Trioxide and Venetoclax Synergize against AML Progenitors by ROS Induction and Inhibition of Nrf2 Activation

“…A positive correlation of AQP9 expression and ATO-induced cytotoxicity has been described for 10 out of 11 myeloid and lymphod cell lines [ 20 ]. Upregulation of AQP9 by G-CSF or Azacytidine enhanced the effect of ATO in non-APL AML cells [ 19 , 21 ]. In addition, several other arsenic-based combination studies, including ATO-tyrosine kinase inhibitor combinations, have been conducted in vitro and in vivo with the aim of overcoming ATO-resistance in non-APL AML cells [ 13 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”