Doxorubicin combined with Alpha Mangostin as pro-apoptotic agents and as potential kinase inhibitors of acute Myeloid Leukaemia

Acute myeloid leukaemia is the most common form of adult leukaemia with several kinase mutations. The FLT3-ITD mutation is one of the most common kinase mutation (20-30%) observed in AML patients and the most involved in the prognosis of AML. Kinases are crucial in controling metabolism, cell division, transcription and programmed cell death. Mutations in tyrosine kinases are well known to signal cancer development and progression. A tyrosine kinase inhibitor, imatinib (Gleevec ST1571), has been successfully used in treating CML by selectively targeting genetically altered tyrosine kinase. However, due to the complexity and the high frequency of the mutations identified in AML, the success rates from commonly used tyrosine kinase inhibitors are low in comparison of CML. The aim of this study is to investigate in vitro, the effect of the phytochemical, α-mangostin, singly and in combination with doxorubicin (DOX) as pro-apoptotic agents and protein kinase inhibitors in AML cell line MOLM13. A range of concentrations (1 to 50 µM) of the above-mentioned phytochemical was used to treat MOLM13 for 72 h with or without DOX (1 µM). CyQuant proliferation assay was used to determine the effect of the test compound on cell viability. Apoptosis and cell cycle analysis were also conducted using a flow cytometer. Expression of proteins were determined using western blot technique. Statistical analysis including ANOVA, Student T test were chosen for comparing the effects from different treatments. Results showed that α mangostin at concentration (≥20 µM) inhibited cell growth in a dose dependent manner. More apoptotic effects were observed when combined with Dox (1 µM), with more TUNEL positive cells and expression of pro apoptotic protein BAK. G2/M phase cell cycle arrest was induced by combination with increased expression of cell cycle arrest protein p21 and reduced expression of phosphorylated CDC25 proteins. Further studies to explore the mechanism of effects when combined are on the way and as kinase inhibitors of FLT3-ITD mutation. Our findings may provide relevant information in identifying potential kinase inhibitors in treating AML