Honokiol: Un componente de la hierba china Magnolia muestra actividad anticancerosa in vitro e in vivo

El Honokiol, un componente activo aislado y purificado de la hierba tradicional china Magnolia, demostró inhibir en crecimiento e inducir la apoptosis -muerte celular programada- de diferentes líneas celulares cancerosas, como leucemia humana, cáncer de colon, y cáncer de pulmón, atenuar las actividades angiogénicas de las células endoteliales humanas in vitro y suprimir el crecimiento del osteosarcoma en ratones atímicos o “nude” -inmunodeficientes-. En este estudio, este equipo de investigación del Departamento de Oncología y Hematología del Hospital Universitario Charité de la Universidad Humboldt en Berlín, Alemania, demostró que el tratamiento de diferentes líneas celulares de carcinoma de pecho humano con honokiol resultó en una inhibición del crecimiento dependiente del tiempo y de la concentración, tanto en líneas celulares positivas para el receptor de estrógenos como para aquellas negativas para éste, así como en líneas celulares resistentes a medicamentos, como líneas celulares resistentes al tamoxifeno y a la adriamicina. La inhibición del crecimiento se asoció a una parada del ciclo celular en la fase G1 y una inducción de apoptosis dependiente de caspasas. En conclusión, este equipo de investigación demostró que honokiol, ya sea solo o en combinación con otras terapias, puede servir como un tratamiento nuevo y prometedor para el tratamiento del cáncer de pecho.

Eur J Pharmacol. 2008 Jun 12.
Anti-tumor effect of honokiol alone and in combination with other anti-cancer agents in breast cancer.
Liu H, Zang C, Emde A, Planas-Silva MD, Rosche M, Kühnl A, Schulz CO, Elstner E, Possinger K, Eucker J.

Department of Oncology and Hematology, University Hospital Charité, Humboldt University of Berlin, Berlin, Germany.

Honokiol, an active component isolated and purified from Chinese traditional herb magnolia, was demonstrated to inhibit growth and induce apoptosis of different cancer cell lines such as human leukaemia, colon, and lung cancer cell lines; to attenuate the angiogenic activities of human endothelial cells in vitro; and to efficiently suppress the growth of angiosarcoma in nude mice. In this study, we have demonstrated that treatment of different human breast cancer cell lines with honokiol resulted in a time- and concentration-dependent growth inhibition in both estrogen receptor-positive and -negative breast cancer cell lines, as well as in drug-resistant breast cancer cell lines such as adriamycin-resistant and tamoxifen-resistant cell lines. The inhibition of growth was associated with a G1-phase cell cycle arrest and induction of caspase-dependent apoptosis. The effects of honokiol might be reversely related to the expression level of human epidermal growth receptor 2, (HER-2, also known as erbB2, c-erbB2) since knockdown of her-2 expression by siRNA significantly enhanced the sensitivity of the her-2 over-expressed BT-474 cells to the honokiol-induced apoptosis. Furthermore, inhibition of HER-2 signalling by specific human epidermal growth receptor 1/HER-2 (EGFR/HER-2) kinase inhibitor lapatinib synergistically enhanced the anti-cancer effects of honokiol in her-2 over-expressed breast cancer cells. Finally, we showed that honokiol was able to attenuate the PI3K/Akt/mTOR (Phosphoinositide 3-kinases/Akt/mammalian target of rapamycin) signalling by down-regulation of Akt phosphorylation and upregulation of PTEN (Phosphatase and Tensin homolog deleted on chromosome Ten) expression. Combination of honokiol with the mTOR inhibitor rapamycin presented synergistic effects on induction of apoptosis of breast cancer cells. In conclusion, honokiol, either alone or in combination with other therapeutics, could serve as a new, promising approach for breast cancer treatment.

PLoS ONE. 2007 Oct 31;2(10):e1096.
Honokiol induces calpain-mediated glucose-regulated protein-94 cleavage and apoptosis in human gastric cancer cells and reduces tumor growth.
Sheu ML, Liu SH, Lan KH.

Institute of Medical Technology, National Chung Hsing University, Taichung, Taiwan. mlsheu@nchu.edu.tw

BACKGROUND: Honokiol, a small molecular weight natural product, has been shown to possess potent anti-neoplastic and anti-angiogenic properties. Its molecular mechanisms and the ability of anti-gastric cancer remain unknown. It has been shown that the anti-apoptotic function of the glucose-regulated proteins (GRPs) predicts that their induction in neoplastic cells can lead to cancer progression and drug resistance. We explored the effects of honokiol on the regulation of GRPs and apoptosis in human gastric cancer cells and tumor growth. METHODOLOGY AND PRINCIPAL FINDINGS: Treatment of various human gastric cancer cells with honokiol led to the induction of GRP94 cleavage, but did not affect GRP78. Silencing of GRP94 by small interfering RNA (siRNA) could induce cell apoptosis. Treatment of cells with honokiol or chemotherapeutics agent etoposide enhanced the increase in apoptosis and GRP94 degradation. The calpain activity and calpain-II (m-calpain) protein (but not calpain-I (micro-calpain)) level could also be increased by honokiol. Honokiol-induced GRP94 down-regulation and apoptosis in gastric cancer cells could be reversed by siRNA targeting calpain-II and calpain inhibitors. Furthermore, the results of immunofluorescence staining and immunoprecipitation revealed a specific interaction of GRP94 with calpain-II in cells following honokiol treatment. We next observed that tumor GRP94 over-expression and tumor growth in BALB/c nude mice, which were inoculated with human gastric cancer cells MKN45, are markedly decreased by honokiol treatment. CONCLUSIONS AND SIGNIFICANCE: These results provide the first evidence that honokiol-induced calpain-II-mediated GRP94 cleavage causes human gastric cancer cell apoptosis. We further suggest that honokiol may be a possible therapeutic agent to improve clinical outcome of gastric cancer.

Clin Cancer Res. 2008 Feb 15;14(4):1248-57.Click here to read Links
Honokiol, a constituent of oriental medicinal herb magnolia officinalis, inhibits growth of PC-3 xenografts in vivo in association with apoptosis induction.
Hahm ER, Arlotti JA, Marynowski SW, Singh SV.

Department of Pharmacology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.

PURPOSE: This study was undertaken to determine the efficacy of honokiol, a constituent of oriental medicinal herb Magnolia officinalis, against human prostate cancer cells in culture and in vivo. EXPERIMENTAL DESIGN: Honokiol-mediated apoptosis was assessed by analysis of cytoplasmic histone-associated DNA fragmentation. Knockdown of Bax and Bak proteins was achieved by transient transfection using siRNA. Honokiol was administered by oral gavage to male nude mice s.c. implanted with PC-3 cells. Tumor sections from control and honokiol-treated mice were examined for apoptotic bodies (terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay), proliferation index (proliferating cell nuclear antigen staining), and neovascularization (CD31 staining). Levels of Bcl-2 family proteins in cell lysates and tumor supernatants were determined by immunoblotting. RESULTS: Exposure of human prostate cancer cells (PC-3, LNCaP, and C4-2) to honokiol resulted in apoptotic DNA fragmentation in a concentration- and time-dependent manner irrespective of their androgen responsiveness or p53 status. Honokiol-induced apoptosis correlated with induction of Bax, Bak, and Bad and a decrease in Bcl-xL and Mcl-1 protein levels. Transient transfection of PC-3 cells with Bak- and Bax-targeted siRNAs and Bcl-xL plasmid conferred partial yet significant protection against honokiol-induced apoptosis. Oral gavage of 2 mg honokiol/mouse (thrice a week) significantly retarded growth of PC-3 xenografts without causing weight loss. Tumors from honokiol-treated mice exhibited markedly higher count of apoptotic bodies and reduced proliferation index and neovascularization compared with control tumors. CONCLUSION: Our data suggest that honokiol, which is used in traditional oriental medicine for the treatment of various ailments, may be an attractive agent for treatment and/or prevention of human prostate cancers.

Blood. 2005 Sep 1;106(5):1794-800.
Honokiol overcomes conventional drug resistance in human multiple myeloma by induction of caspase-dependent and -independent apoptosis.
Ishitsuka K, Hideshima T, Hamasaki M, Raje N, Kumar S, Hideshima H, Shiraishi N, Yasui H, Roccaro AM, Richardson P, Podar K, Le Gouill S, Chauhan D, Tamura K, Arbiser J, Anderson KC.

Department of Medical Oncology, Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115, USA.

Honokiol (HNK) is an active component purified from magnolia, a plant used in traditional Chinese and Japanese medicine. Here we show that HNK significantly induces cytotoxicity in human multiple myeloma (MM) cell lines and tumor cells from patients with relapsed refractory MM. Neither coculture with bone marrow stromal cells nor cytokines (interleukin-6 and insulin-like growth factor-1) protect against HNK-induced cytotoxicity. Although activation of caspases 3, 7, 8, and 9 is triggered by HNK, the pan-caspase inhibitor z-VAD-fmk does not abrogate HNK-induced apoptosis. Importantly, release of an executioner of caspase-independent apoptosis, apoptosis-inducing factor (AIF), from mitochondria is induced by HNK treatment. HNK induces apoptosis in the SU-DHL4 cell line, which has low levels of caspase 3 and 8 associated with resistance to both conventional and novel drugs. These results suggest that HNK induces apoptosis via both caspase-dependent and -independent pathways. Furthermore, HNK enhances MM cell cytotoxicity and apoptosis induced by bortezomib. In addition to its direct cytotoxicity to MM cells, HNK also represses tube formation by endothelial cells, suggesting that HNK inhibits neovascurization in the bone marrow microenvironment. Taken together, our results provide the preclinical rationale for clinical protocols of HNK to improve patient outcome in MM.

Blood. 2005 Jul 15;106(2):690-7.
The natural product honokiol induces caspase-dependent apoptosis in B-cell chronic lymphocytic leukemia (B-CLL) cells.
Battle TE, Arbiser J, Frank DA.

Department of Medical Oncology, Mayer 522B, Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115, USA.

B-cell chronic lymphocytic leukemia (B-CLL) remains an incurable disease that requires innovative new approaches to improve therapeutic outcome. Honokiol is a natural product known to possess potent antineoplastic and antiangiogenic properties. We examined whether honokiol can overcome apoptotic resistance in primary tumor cells derived from B-CLL patients. Honokiol induced caspase-dependent cell death in all of the B-CLL cells examined and was more toxic toward B-CLL cells than to normal mononuclear cells, suggesting greater susceptibility of the malignant cells. Honokiol-induced apoptosis was characterized by the activation of caspase-3, -8, and -9 and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP). Exposure of B-CLL cells to honokiol resulted in up-regulation of Bcl2-associated protein (Bax) and down-regulation of the expression of the key survival protein myeloid-cell leukemia sequence 1 (Mcl-1), which is associated with response to treatment in B-CLL patients. In addition, B-CLL cells pretreated with interleukin-4 (IL-4), a cytokine known to support B-CLL survival, underwent apoptosis when subsequently incubated with honokiol, indicating that honokiol could also overcome the prosurvival effects of IL-4. Furthermore, honokiol enhanced cytotoxicity induced by fludarabine, cladribine, or chlorambucil. These data indicate that honokiol is a potent inducer of apoptosis in B-CLL cells and should be examined for further clinical application either as a single agent or in combination with other anticancer agents.