METHODOLOGY/PRINCIPAL FINDINGS: Rats were divided into 7 groups. Groups 1 and 2 were orally administered with Tween 20 (10% v/v). Group 3 was orally administered with 20 mg/kg omeprazole (10% Tween 20). Groups 4-7 received 10, 20, 40, and 80 mg/kg of the complex (10% Tween 20), respectively. Tween 20 (10% v/v) was given orally to group 1 and absolute ethanol was given orally to groups 2-7, respectively. Rats were sacrificed after 1 h. Group 2 exhibited severe superficial hemorrhagic mucosal lesions. Gastric wall mucus was significantly preserved by the pre-treatment complex. The results showed a significant increase in glutathione (GSH), superoxide dismutase (SOD), nitric oxide (NO), and Prostaglandin E2 (PGE(2)) activities and a decrease in malondialdehyde (MDA) level. Histology showed marked reduction of hemorrhagic mucosal lesions in groups 4-7. Immunohistochemical staining showed up-regulation of Hsp70 and down-regulation of Bax proteins. PAS staining of groups 4-7 showed intense stain uptake of gastric mucosa. The acute toxicity revealed the non-toxic nature of the compound.
CONCLUSIONS/SIGNIFICANCE: The gastroprotective effect of the Copper (II) complex may possibly be due to preservation of gastric wall mucus; increase in PGE(2) synthesis; GSH, SOD, and NO up-regulation of Hsp70 protein; decrease in MDA level; and down-regulation of Bax protein.
METHODS: α-Mangostin (AM) was isolated from C. arborescens and its cell death mechanism was investigated. AM-induced cytotoxicity was observed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Acridine orange/propidium iodide staining and annexin V were used to detect cells in early phases of apoptosis. High-content screening was used to observe the nuclear condensation, cell permeability, mitochondrial membrane potential, and cytochrome c release. The role of caspases-3/7, -8, and -9, reactive oxygen species, Bcl-2 and Bax expression, and cell cycle arrest were also investigated. To determine the role of the central apoptosis-related proteins, a protein array followed by immunoblot analysis was conducted. Moreover, the involvement of nuclear factor-kappa B (NF-κB) was also analyzed.
RESULTS: Apoptosis was confirmed by the apoptotic cells stained with annexin V and increase in chromatin condensation in nucleus. Treatment of cells with AM promoted cell death-transducing signals that reduced MMP by downregulation of Bcl-2 and upregulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol. The released cytochrome c triggered the activation of caspase-9 followed by the executioner caspase-3/7 and then cleaved the PARP protein. Increase of caspase-8 showed the involvement of extrinsic pathway. AM treatment significantly arrested the cells at the S phase (P<0.05) concomitant with an increase in reactive oxygen species. The protein array and Western blotting demonstrated the expression of HSP70. Moreover, AM significantly blocked the induced translocation of NF-κB from cytoplasm to nucleus.
CONCLUSION: Together, the results demonstrate that the AM isolated from C. arborescens inhibited the proliferation of MDA-MB-231 cells, leading to cell cycle arrest and programmed cell death, which was suggested to occur through both the extrinsic and intrinsic apoptosis pathways with involvement of the NF-κB and HSP70 signaling pathways.
MATERIALS AND METHODS: K. odoratissima methanol extract (KME) was prepared, and MTT assay was used to evaluate the cytotoxicity. To identify the cytotoxic compound, a bioassay-guided investigation was performed on methanol extract. 8-Hydroxy-ar-turmerone was isolated as a bioactive compound. In vivo study was performed in the breast cancer rat model. LA7 cell line was used to induce the breast tumor. Histopathological and expression changes of PCNA, Bcl-2, Bax, p27 and p21 and caspase-3 were examined. The induction of apoptosis was tested using Annexin V-fluorescein isothiocyanate (FITC) assay. To confirm the intrinsic pathway of apoptosis, caspase-7 and caspase-9 assays were utilized. In addition, cell cycle arrest was evaluated.
RESULTS: Our results demonstrated that K. odoratissima has an obvious effect on the arrest of proliferation of cancer cells. It induced apoptosis, transduced the cell death signals, decreased the threshold of mitochondrial membrane potential (MMP), upregulated Bax and downregulated Bcl-2.
CONCLUSION: This study demonstrated that K. odoratissima exhibits antitumor activity against breast cancer cells via cell death and cell cycle arrest.