Immunomolecular evaluation of dihydroartemisinin effects on apoptosis in chronic lymphocytic leukemia cell lines

INTRODUCTION

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, has recently shown to induce apoptosis in many types of cancer cells. In this study, we aimed to determine the effects of DHA on apoptosis in human chronic lymphocytic leukemia (CLL) cell lines.

METHODS

The cells were treated separately and combined by DHA and Fludurabine (FLU) during 24, 48 and 72 hours. The cell viabilities determined by XTT method. Following separate and combined treatment of IC50 concentrations of DHA and FLU to the cells during 24 hours, the cells were analyzed by flow cytometry to determine the effects on apopotis staining with AnnexinV FITC and PI. mRNA and protein expression levels of TCTP, Mcl-1, Bcl-2, Bax and Caspase-3 were analyzed to find out the molecular mechanisms of apoptosis by using quantitative real-time PCR and flow cytometric methods.

RESULTS

Treatment with DHA alone or in combination with FLU induced apoptosis in a dose dependent manner in CLL cells. DHA alone was more effective than FLU alone or combined treatment with DHA and FLU. Our results suggest that Bcl-2 protein family member Bax was active in the apoptotic response of CLL cells after DHA treatment. Moreover, the apoptotic response induced by DHA was independent from the p53 mutation status of the CLL cells.

CONCLUSION

DHA might be a potential anti-cancer therapeutic for CLL.

High Bax/Bcl-2 ratio is associated with good prognosis and better survival in patients with B cell chronic lymphocytic leukemia

Determination of Bax/Bcl-2 ratio may be a good predictive tool to recognize chronic lymphocytic leukemia (CLL) patients' outcome and prognosis to decide the time and type of therapy. This prospective study was carried out on 100 patients with newly diagnosed CLL. Bax and Bcl-2 expression in peripheral blood were measured by flow-cytometry. The association of Bax/Bcl-2 ratio with CLL laboratory markers, Rai stage, overall survival (OS) and progression-free survival (PFS) at 18 months was investigated. The sensitivity and specificity of Bax/Bcl-2 in predicting survival was evaluated. The best cut-off value of Bax/Bcl-2 ratio to predict the survival, detected by receiver operating characteristic (ROC) curve, was 1.2 with 80 % sensitivity and 60.86 % specificity. A ratio of ≤1.20 was detected in 78 % of patients and was associated with worse prognosis. A lower Bax/Bcl-2 ratio was associated with higher modified Rai stage at time of diagnosis and a significantly shorter both OS (64.1 % versus 90.9 %, p < 0.026) and PFS (66.7 % versus 90.9 %, p < 0.031) at 18 months. In multivariate analysis, bax/bcl-2 ≤ 1.2 was an independent prognostic factor for overall survival, (p = 0.025). We concluded that lower Bax /Bcl-2 ratios were associated with worse prognosis as evidenced by lower OS and PFS in CLL patients. It was also associated with markers of high tumor burden and unfavorable prognostic markers. Recognition of patients with low Bax /Bcl-2 ratio would make them good candidates for the novel Bcl-2 inhibitory targeted chemotherapy to avoid resistance to the traditional therapy.