Berbamine Induces Apoptosis and Lowers Expression Levels of Bcr/Abl and Survivin Gene and Bcr/Abl-Related P²¹⁰ in Different Types of Leukemic Cell Lines Cells.

Berbamine is a kind of bis-benzylisoquinoline extracted from Chinese herb. Berbamine and its derivatives have been proven to be a kind of calmodulin antagonist which could obviously inhibit the proliferation of different kinds of cell lines, such as hepatoma, Hela cells etc. Berbamine has been shown to induce apoptosis of HL-60 cells in vitro in a cell type-specific manner. However, main components of Berbamine induced apoptosis pathway remain to be identified. We studied Berbamine induced apoptosis of different types of leukemic cell lines cells and its possible molecular mechanisms in vitro. The results revealed that Berbamine could significantly induce apoptosis in K562, NB4 and Jurkat leukemia cell lines cells in a time- and dosage-dependent manner. With electron microscope and DNA electrophoresis, the typical apoptosis morphologic changes and DNA ladder were clearly observed. As detected by flow cytometry, the percentage of the apoptotic cells in K562, Jurkat and NB4 cells treated with 8.0μg.L⁻¹ Berbamine increased to 49.07±4.73%, 35.57±5.49%, 54.40±4.56% (P value<0.01), respectively. Using semi-quantity RT-PCR assay, the expression level of survivin gene was lower. in K562 cells treated with 8.0μg.L⁻¹ Berbamine than that in untreated cells (0.69±0.02 vs 1.09±0.01, P<0.01),in a time-dependent manner; as well as the expression level of survivin gene was lower. in Jurkat cells treated with 16.0μg.L⁻¹ Berbamine than that in untreated cells (1.34±0.02 vs 2.18±0.03, P<0.01). Similarly, bcr/abl expression was weaker in K562 cells treated with 8.0μg.L⁻¹ Berbamine than that in untreated cells (0.91±0.02 vs 1.19±0.02, P<0.01), while no difference was found between Ara-C treated K562 cells and untreated treated cells. In the other hand, Using Western Blot assay, the level of bcr/abl-related P²¹⁰ was lower in K562 cells treated with 8μg.L⁻¹ Berbamine than that in untreated cells (0.63±0.01 vs 1.04±0.02, P<0.01). AS a comparison, the level of P²¹⁰ was also lower in same cells treated with 1.0μg.L⁻¹ STI571 than that in untreated cells (0.58±0.02 vs 0.93±0.03, P value P<0.01).

In summary, Berbamine extracted from Chinese herb can obviously induce apoptosis in different kinds of leukemic cell lines including K562, Jurkat, NB4 in a time-and dosage-dependent manner in vitro. The down-regulation expressions of survivin gene, bcr/abl gene and bcr/abl -related P²¹⁰ may play an important role in the apoptotic effect of Berbamine in leukemic cells.