α-Mangostin, singly and in combination with Doxorubicin, as pro-apoptotic agents and protein kinase inhibitors In the AML cell line, Molm13

Acute myeloid leukaemia is the most common form of adult leukaemia with several kinase mutations. The FLT3-ITD mutation is a common kinase mutation (20-30%) observed in AML patients and the most involved in the prognosis of AML. Kinases are crucial in controlling different cellular activities, and mutations 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 to 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. The phytochemical α-mangostin (1- 50 µM) was used to treat MOLM13 for 72 h. CyQUANT proliferation assay was used to determine its effect on cell viability. Apoptosis and cell cycle analysis were conducted using a flow cytometer. Expression of proteins was determined using western blot technique. Statistical analysis including ANOVA, Student T-test were chosen for comparing the effects of different treatments. Results showed that α-mangostin at the concentration (≥20 µM) inhibited cell growth in a dose-dependent manner. More apoptotic effects were observed when α-mangostin (20 µM) was combined with Dox (1 µM), with more TUNEL positive cells and increased expression of the pro-apoptotic protein BAK. The G2/M phase cell cycle arrest was induced by combination with increased expression of p21 protein and reduced expression of the phosphorylated CDC25 proteins. Further studies to explore the mechanism of potential kinase inhibition of FLT3-ITD mutation is currently carried out. Our findings may provide relevant information in identifying potential kinase inhibitors in treating AML.