Berbamine inhibits proliferation and induces apoptosis of KU812 cells by increasing Smad3 activity

Abstract

Abstract:Objective: The cytotoxic effect of berbamine on chronic myeloid leukemia (CML) cell line KU812 was evaluated, and the mechanisms of its action were explored. Methods: The effect of berbamine on the KU812 cell growth was determined by methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry was used to profile cell cycle alteration upon berbamine treatment. Reverse transcription polymerase chain reaction (RT-PCR) was carried out to determine the transcripts of transforming growth factor-β (TGF-β) receptors (TβRs), Smad3, c-Myc, cyclin D1, p21Cip1 (p21), and p27 Kip1 (p27). Changes in the protein levels of total Smad3, phosphorylated Smad3, the downstream targets of Smad3, and specific apoptosis-related factors were evaluated by Western blotting. Results: Berbamine inhibited KU812 cell proliferation in a dose-and time-dependent manner, and the half maximal inhibitory concentration (IC 50 ) values for treatments of 24, 48, and 72 h were 5.83, 3.43, and 0.75 μg/ml, respectively. Berbamine induced G 1 arrest as well as apoptosis in KU812 cells. Transcriptions of Smad3 and p21 were up-regulated, while those of TβRI, TβRII, c-Myc, cyclin D1 and p27 were not changed significantly. The protein levels of both total Smad3 and phosphorylated Smad3 were both up-regulated after berbamine treatment, together with decreased c-Myc and cyclin D1 and increased p21. Meanwhile, the levels of the anti-apoptotic proteins, such as Bcl-2 and Bcl-xL, were decreased, whereas pro-apoptotic Bax was increased. Conclusions: Berbamine suppresses KU812 cell proliferation through induction of cell cycle arrest in G 1 and apoptosis. It activates Smad3 without additional stimulation of TGF-β, and alters the levels of the Smad3 downstream targets, including c-Myc, cyclin D1 and p21. Our findings suggest that berbamine is a promising drug in the treatment of advanced stage patients with CML.

CaMKII γ, a critical regulator of CML stem/progenitor cells, is a target of the natural product berbamine

“…17,18 Extensive scrutiny of its molecular targets and mechanism of action in the past few decades has provided important insights. At the cellular level, berbamine exhibits significantly antiproliferative activities of a variety of leukemia, [17][18][19][20][21] lymphoma, 22 multiple myeloma, 23 and solid tumor cell lines. [24][25][26][27] At the molecular level, berbamine-mediated antitumor activity was shown to be involved in PI3K/Akt, 22 nuclear factor kappaB, 23 Fas-mediated apoptosis, 26 calmodulin, 28,29 phospholipase A2, 16,30,31 P-glycoprotein, 24 and telomerase activity.…”

Berbamine Enhances the Antineoplastic Activity of Gemcitabine in Pancreatic Cancer Cells by Activating Transforming Growth Factor‐β/Smad Signaling

“…In recent years, berbamine and its synthetic derivatives have been demonstrated to possess a series of potentially valuable biological activities such as promotion of cell apoptosis in hepatocellular carcinoma, significant inhibition of cell production and migration in non‐small cell lung cancer (Duan et al, ), and restoration of drug susceptibility in breast carcinoma (Liu et al, ). The antitumor activity of berbamine may be due to involvement of inhibition of nuclear factor‐κ binding signaling pathways (Wei et al, ) as well as activation of some apoptosis‐related proteins such as the Bcl‐2 family proteins (Liang et al, ). However, the antitumor effect of berbamine in pancreatic cancer and the underlying mechanisms have not been fully understood yet.…”

Bersavine: A Novel Bisbenzylisoquinoline Alkaloid with Cytotoxic, Antiproliferative and Apoptosis-Inducing Effects on Human Leukemic Cells

“…Bersavine, in structural analogy with berbamine, incorporates two tetrahydrobenzylisoquinoline moieties combined through two ether linkages. Berbamine has been known for its promising cytotoxic activity on human cancer cell lines in vitro for a long time, and it has also been shown to stimulate normal hematopoiesis and enhance immune function in cancer patients [6]. Berbamine also exerts anti-inflammatory effects by inhibiting nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signalling pathways [7].…”