PB1714 STUDY ON MECHANISM OF MATERIA MEDICA HEDYOTIS DIFFUSA REGULATING MITOCHONDRIAL MORPHOLOGY AND FUNCTION TO INDUCE APOPTOSIS IN KG1A CELLS
Authors: Shen M. , Xu R. , Zhang S. , Wu X. , Wang Y. , Guo Y. , Ding S. , Cui S. 
Published: June 2019

Background:

Recent studies have indicated that Chinese herbal medicine plays an irreplaceable role in the treatment of leukemia. Mitochondria are the main site of intracellular bio‐oxidation and energy metabolism. Regulation of mitochondria to induce leukemia cells apoptosis has become an important target in the treatment of leukemia. However, the mechanism of mitochondrial morphological and functional changes mediating the intervention of traditional Chinese medicine on leukemia cells apoptosis is still unclear.

Aims:

In our study, we try to show that Hedyotis diffusa can change the mitochondrial morphology by interfering with mitochondrial fusion and fission proteins in KG1a cells, resulting in increased reactive oxygen species (ROS) in mitochondrial matrix, loss of mitochondrial membrane potential, dysfunction of oxidative respiration and energy metabolism, and promoting mitochondrial‐related apoptotic factors Cyt‐C, Apaf‐1, Smac/Diablo and AIF. These changes eventually induce the KG‐1a cells apoptosis.

Methods:

To prove the intervention of Chinese herbal medicine can inhibit the proliferation of leukemia cells in vivo, we established a human acute myeloid leukemia model with NOD/SCID mice and KG‐1a cell line as our research platform. The model was randomly divided into experimental group and control group. The expression of mitochondrial apoptotic factors Cyt‐C, Apaf‐1, Smac/Diablo and AIF in NOD/SCID mice bone marrow was detected by immunohistochemistry. After treatment, the apoptosis rate of leukemia cells derived from the mice in experimental group was significantly increased (P < 0.01), and the expressions of Cyt‐C, Apaf‐1, Smac/Diablo and AIF in bone marrow were increased (P < 0.05), and the expressions of Cyt‐C and Apaf‐1 were significantly increased (P < 0.01), compared with control group.

And then, we expect to explore the relationship between leukemia cells apoptosis and mitochondrial oxidative respiration and energy metabolism in vitro. Therefore, the water extract of Materia Medica Hedyotis diffusa was used to treat KG‐1a cells. After 48 hours, the apoptosis rate and G1 phase arrest rate of KG‐1a cells in experimental group were significantly increased in a dose‐dependent manner. The morphology, number and distribution of mitochondria were observed by transmission electron microscopy. After treatment, western blot assay showed that the expressions of Cyt‐C, Apaf‐1, Smac/Diablo and AIF were up‐regulated in KG1a cells. ROS was released in large quantities, mitochondrial membrane potential was lost, oxidative respiration and energy metabolism were abnormal, and apoptosis‐related factors were released.

Finally, we explored the mechanism of mitochondrial morphological and functional changes. After treatment, mitochondrial fusion proteins Mfn‐1, Mfn‐2, Opa‐1 and fission proteins Drp‐1, Fis‐1, Mff in KG1a cells were detected. Remarkably, the expressions of Mfn‐1, Mfn‐2, Opa‐1 were down‐regulated, and Drp‐1, Fis‐1, Mff were up‐regulated.

Results:

Hedyotis diffusa demonstrated that Hedyotis diffusa could lead to mitochondrial morphological damage by interventing the expressions of mitochondrial fusion and fission proteins, thereby impacting mitochondrial oxidative respiration and energy metabolism, and ultimately inducing KG‐1a cells apoptosis.

Summary/Conclusion:

In conclusion, our study is of great significance to find more effective treatment strategies of Chinese herbal medicine targeting leukemia.In conclusion, our study is of great significance to find more effective treatment strategies of Chinese herbal medicine targeting leukemia.