p53 Cooperates berberine-induced growth inhibition and apoptosis of non-small cell human lung cancer cells in vitro and tumor xenograft growth in vivo

Genetic evidence for inhibition of bacterial division protein FtsZ by berberine

Background

Berberine is a plant alkaloid that is widely used as an anti-infective in traditional medicine. Escherichia coli exposed to berberine form filaments, suggesting an antibacterial mechanism that involves inhibition of cell division. Berberine is a DNA ligand and may induce filamentation through induction of the SOS response. Also, there is biochemical evidence for berberine inhibition of the cell division protein FtsZ. Here we aimed to assess possible berberine mechanism(s) of action in growing bacteria using genetics tools.

Methodology/Principal Findings

First, we tested whether berberine inhibits bacterial growth through DNA damage and induction of the SOS response. The SOS response induced by berberine was much lower compared to that induced by mitomycin C in an SOS response reporter strain. Also, cell filamentation was observed in an SOS-negative E. coli strain. To test whether berberine inhibits FtsZ, we assessed its effects on formation of the cell division Z-rings, and observed a dramatic reduction in Z-rings in the presence of berberine. We next used two different strategies for RNA silencing of ftsZ and both resulted in sensitisation of bacteria to berberine, visible as a drop in the Minimum Inhibitory Concentration (MIC). Furthermore, Fractional Inhibitory Concentration Indices (FICIs) showed a high level of synergy between ftsZ silencing and berberine treatment (FICI values of 0.23 and 0.25 for peptide nucleic acid- and expressed antisense RNA-based silencing of ftsZ, respectively). Finally, over-expression of ftsZ led to a mild rescue effect in berberine-treated cells.

Conclusions

The results argue against DNA binding as the primary mechanism of action of berberine and support the hypothesis that its antibacterial properties are due to inhibition of the cell division protein FtsZ. In addition, the genetic approach used here provides a means to rapidly test the activity of other putative FtsZ inhibitors.

Degradation of MDM2 by the interaction between berberine and DAXX leads to potent apoptosis in MDM2-overexpressing cancer cells

Berberine, a natural product derived from a plant used in Chinese herbal medicine, is reported to exhibit anticancer effects; however, its mechanism of action is not clearly defined. Herein, we demonstrate that berberine induces apoptosis in acute lymphoblastic leukemia (ALL) cells by downregulating the MDM2 oncoprotein. The proapoptotic effects of berberine were closely associated with both the MDM2 expression levels and p53 status of a set of ALL cell lines. The most potent apoptosis was induced by berberine in ALL cells with both MDM2 overexpression and a wild-type (wt)-p53, whereas no proapoptotic effect was detected in ALL cells that were negative for MDM2 and wt-p53. In contrast to the conventional chemotherapeutic drug doxorubicin, which induces p53 activation and a subsequent upregulation of MDM2, berberine strongly induced persistent downregulation of MDM2 followed by a steady-state activation of p53. We discovered that downregulation of MDM2 in ALL cells by berberine occurred at a posttranslational level through modulation of death domain-associated protein (DAXX), which disrupted the MDM2-DAXX-HAUSP interactions and thereby promoted MDM2 self-ubiquitination and degradation. Given that MDM2-overexpressing cancer cells are commonly chemoresistant, our findings suggest that this naturally derived agent may have a highly useful role in the treatment of cancer patients with refractory disease.

A systematic review of the anticancer properties of berberine, a natural product from Chinese herbs

Natural products represent a rich reservoir of potential small chemical molecules exhibiting antiproliferation and anticancer properties. An example is berberine, a protoberberine alkaloid widely distributed in medical plants used in traditional Chinese prescriptions. Recent advances have shown that berberine exerts anticancer activities both in vitro and in vivo through different mechanisms. Berberine shows inhibitory effects on the proliferation and reproduction of certain tumorigenic microorganisms and viruses, such as Heliobacter pylori and hepatitis B virus. Transcriptional regulation of some oncogene and carcinogenesis-related gene expression and interaction with both DNA and RNA are also well documented. Besides, berberine is a broad spectrum enzyme inhibitor, which affects N-acetyltransferase, cyclooxygenase-2, and topoisomerase activities and gene/protein expression. These actions, together with the regulation of reactive oxygen species production, mitochondrial transmembrane potential, and nuclear factor-kappaB activation might underlie its antiproliferative and proapoptotic effects. More importantly, the suppression of tumor growth and metastasis, the beneficial application in combined medication, and the improvement of multidrug resistance both in vivo and in vitro clearly show its potential as an alternative medicine for tumor chemotherapy.

Berberine and Coptidis rhizoma as novel antineoplastic agents: a review of traditional use and biomedical investigations

ETHNOPHARMACOLOGICAL RELEVANCE

Coptidis rhizoma (huanglian) and its major component, berberine, have drawn extensive attention toward their antineoplastic effects in the recent years. The antineoplastic effects are related to the Chinese Medicine (CM) properties of huanglian in treating diseases by removing damp-heat and purging fire and counteracting toxicity.

AIM OF THE REVIEW

To trace the long history of the traditional use of huanglian from folk medicines, especially from Chinese medicine, to recent pharmacological studies of huanglian and berberine, with an emphasis on their antineoplastic effects and the promise as novel antineoplastic agents.

METHODS

A total of seven databases were extensively searched for literature research. The terms and keywords for searching included huanglian, berberine, Coptis, Coptidis rhizoma, anticancer, anti-invasion, antimatastasis and mechanism. The papers including ours with studies on anticancer and mechanism, pharmacology and toxicology of huanglian and/or berberine were focused.

RESULTS

In view of traditional use, the anticancer effects of huanglian can be ascribed to its CM trait by removing damp-heat, fire and toxicity. From modern biomedical studies, anticancer effects have been demonstrated in both huanglian and berberine. The underlying molecular mechanisms involve cell-cycle arrest, apoptosis induction and anti-inflammation. Berberine is an essential anticancer compound in huanglian. In some studies, the use of huanglian was shown to be more effective and beneficial than the use of berberine alone. The presence of other protoberberine-type alkaloids in huanglian might give synergistic effects for the anticancer effects. Berberine also demonstrates effects of antiangiogenesis, anti-invasion and anti-metastasis in some cancer cell lines, however, more investigations are required to unravel the underlying mechanisms involved.

CONCLUSIONS

The modern evidences of treating cancer with huanglian and berberine have a strong linkage with traditional concept and rules of using huanglian in CM practice. As anticancer candidates with low toxicity, berberine and its altered structure, as well as huanglian and its formulae, will attract scientists to pursue the potential anticancer effects and the mechanisms by using technologies of genomics, proteomics and other advanced approaches. On the other hand, relatively few in vivo studies have been conducted on anticancer effects of huanglian and berberine. The clinical application of berberine or huanglian as novel cancer therapeutic agents requires in vivo validations and further investigations of their anticancer mechanisms.

The in vitro and in vivo apoptotic effects of Mahonia oiwakensis on human lung cancer cells

Both the root and stem bark of Mahonia species were popular folk medicines. The plant has several proven biological activities including anti-bacterial, anti-fungal, and anti-inflammatory effects. However, Mahonia has not been studied for its anticancer effects. In the present study, we made extracts from Mahonia oiwakensis (MOE), a selected species in Taiwan, and investigated their effects on various human lung cells. We found that MOE-induced apoptotic death in human A549 non-small-cell lung carcinoma (NSCLC) cells in a dose- and time-dependent manner. Treatment with the extracts also caused an increase in the sub-G1 fraction of cells, chromosome condensation, and DNA fragmentation. The mitochondrial-mediated pathway was implicated in this MOE-induced apoptosis as evidenced by the activation of the caspase cascade, cleavage of poly (ADP-ribose) polymerase (PARP), disruption of mitochondrial membrane potential, and release of cytochrome C. A higher ratio of Bax/Bcl-2 proteins and cleavage of Bid were also observed in MOE-induced cell apoptosis. In A549 tumor-xenografted nude mice, MOE also retarded in vivo proliferation (P<0.05) and induced apoptosis in tumor cells, as shown by a decrease in Ki-67-positive staining (P<0.05) and increased transferase-mediated dUTP nick-end labeling (TUNEL)-positive staining (P<0.05). In conclusion, MOE inhibits the growth of human lung cancer cells in vitro and in vivo, suggesting that it may have therapeutic potential against human lung cancer.

Berberine induces p53-dependent cell cycle arrest and apoptosis of human osteosarcoma cells by inflicting DNA damage

Alkaloid berberine is widely used for the treatment of diarrhea and other diseases. Many laboratory studies showed that it exhibits anti-proliferative activity against a wide spectrum of cancer cells in culture. In this report we studied the mechanisms underlying the inhibitory effects of berberine on human osteosarcoma cells and on normal osteoblasts. The inhibition was largely attributed to cell cycle arrest at G1 and G2/M, and to a less extent, to apoptosis. The G1 arrest was dependent on p53, as G1 arrest was abolished in p53-deficient osteosarcoma cells. The induction of G1 arrest and apoptosis was accompanied by a p53-dependent up-regulation of p21 and pro-apoptotic genes. However, the G2/M arrest could be induced by berberine regardless of the status of p53. Interestingly, DNA double-strand breaks, as measured by the phosphorylation of H2AX, were remarkably accumulated in berberine-treated cells in a dose-dependent manner. Thus, one major mechanism by which berberine exerts its growth-inhibitory effect is to inflict genomic lesions on cells, which in turn trigger the activation of p53 and the p53-dependent cellular responses including cell cycle arrest and apoptosis.