Calanquinone A induces anti-glioblastoma activity through glutathione-involved DNA damage and AMPK activation.

Glioblastoma, a highly malignant glioma, is resistant to both radiation and chemotherapy and is an intractable problem in clinical treatment. New therapeutic approaches are in urgent need. Calanquinone A, an herbal constituent, displayed anti-proliferative activity against glioblastoma cells, including A172, T98 and U87. Flow cytometric analysis showed an S phase arrest and a subsequent apoptosis to calanquinone A action. Further identification demonstrated a rapid increase of γH2A.X formation at S phase. The data together with comet tail formation and Chk1 activation indicated DNA damage response. N-acetyl cysteine (an antioxidant and a glutathione precursor) and exogenously applied glutathione, but not trolox (an antioxidant), completely abolished calanquinone A-induced effects. Immunofluorescence assay revealed that calanquinone A decreased the intracellular glutathione levels in both A172 and T98 cells. However, calanquinone A, by itself, did not conjugate glutathione. The data suggested that the decrease of cellular glutathione predominantly contributed to the anticancer mechanism. Furthermore, calanquinone A induced the activation of AMP-activated protein kinase (AMPK) and the inhibition of p70S6K activity. Rhodamine efflux assay showed that calanquinone A did not block efflux activity, indicating that calanquinone A was not a P-glycoprotein substrate. In summary, the data suggest that calanquinone A displays anti-glioblastoma activity through a decrease of cellular glutathione levels that subsequently induces DNA damage stress and AMPK activation, leading to cell cycle arrest at S-phase and apoptotic cell death. Furthermore, calanquinone A does not serve as a P-glycoprotein substrate, suggesting a potential for further development in anti-glioblastoma therapy.

Moniliformediquinone induces in vitro and in vivo antitumor activity through glutathione involved DNA damage response and mitochondrial stress in human hormone refractory prostate cancer.

PURPOSE: Hormone refractory metastatic prostate cancer is a major obstacle in clinical treatment. The key focus of this study was the discovery and development of a potential agent for this disease. MATERIALS AND METHODS: Several pharmacological and biochemical assays were used to characterize the apoptotic signaling pathways of moniliformediquinone, a natural product, in hormone refractory metastatic prostate cancer. RESULTS: Moniliformediquinone induced cell cycle arrest at the S-phase and subsequent apoptosis in the hormone refractory metastatic prostate cancer cell lines PC-3 and DU-145. Further examination showed that moniliformediquinone induced a DNA damage response associated with Chk1, Chk2, c-Jun and JNK activation. Mitochondrial apoptosis pathways were also activated, including loss of mitochondrial membrane potential, cytochrome c release, and activation of caspase-9 and 3. The antioxidant and glutathione precursor N-acetylcysteine, and the antioxidant Trolox™ completely abolished moniliformediquinone induced generation of reactive oxygen species. However, N-acetylcysteine but not Trolox blocked moniliformediquinone mediated apoptosis and related signaling cascades. Further identification showed that moniliformediquinone alone did not conjugate glutathione but significantly decreased cellular glutathione levels. The in vivo study revealed that moniliformediquinone completely inhibited tumor growth with no weight loss. CONCLUSIONS: Our data suggest that moniliformediquinone is a potential anticancer agent for hormone refractory metastatic prostate cancer by decreasing cellular glutathione, leading to a DNA damage response and cell cycle arrest at the S-phase. Mitochondrial stress also occurs due to moniliformediquinone action through loss of mitochondrial membrane potential and cytochrome c release, which in turn induce the activation of caspase cascades and apoptotic cell death.

Microfluidic controlling monodisperse microdroplet for 5-fluorouracil loaded genipin-gelatin microcapsules.

This paper demonstrates a proof-of-concept approach for producing genipin-gelatin microcapsules of precisely controlled and monodisperse size distributions by the microfluidic channels. We have demonstrated that one could control the size of emulsions from 130 microm to 580 microm in diameter (with a variation of less than 5%) by altering the relative sheath/sample flow rate ratio. In addition, Results show that the encapsulation and in vitro release of a model drug, 5-fluorouracil, to enhance the effect of controlled release. We demonstrated that the appropriate particle size for different release patterns is predictable, enabling better application of genipin-gelatin microcapsules as a drug carrier. The proposed microfluidic chip is capable of generating relatively uniform micro-droplets with well controllable diameter, and it has the added advantages of being a simple, low cost, and high throughput process.