Activations of Both Extrinsic and Intrinsic Pathways in HCT 116 Human Colorectal Cancer Cells Contribute to Apoptosis through p53-Mediated ATM/Fas Signaling by Emilia sonchifolia Extract, a Folklore Medicinal Plant.

Emilia sonchifolia (L.) DC (Compositae), an herbaceous plant found in Taiwan and India, is used as folk medicine. The clinical applications include inflammation, rheumatism, cough, cuts fever, dysentery, analgesic, and antibacteria. The activities of Emilia sonchifolia extract (ESE) on colorectal cancer cell death have not been fully investigated. The purpose of this study explored the induction of apoptosis and its molecular mechanisms in ESE-treated HCT 116 human colorectal cancer cells in vitro. The methanolic ESE was characterized, and γ-humulene was formed as the major constituent (63.86%). ESE induced cell growth inhibition in a concentration- and time-dependent response by MTT assay. Apoptotic cells (DNA fragmentation, an apoptotic catachrestic) were found after ESE treatment by TUNEL assay and DNA gel electrophoresis. Alternatively, ESE stimulated the activities of caspase-3, -8, and -9 and their specific caspase inhibitors protected against ESE-induced cytotoxicity. ESE promoted the mitochondria-dependent and death-receptor-associated protein levels. Also, ESE increased ROS production and upregulated the levels of ATM, p53, and Fas in HCT 116 cells. Strikingly, p53 siRNA reversed ESE-reduced viability involved in p53-mediated ATM/Fas signaling in HCT 116 cells. In summary, our result is the first report suggesting that ESE may be potentially efficacious in the treatment of colorectal cancer.

Investigation of anti-leukemia molecular mechanism of ITR-284, a carboxamide analog, in leukemia cells and its effects in WEHI-3 leukemia mice.

ITR-284, a potent anti-leukemia agent of carboxamide derivative, has been shown to inhibit the proliferation of leukemia cells. In this study, the underlying molecular mechanisms in vitro and anti-leukemia activity in vivo of ITR-284 were investigated. ITR-284 reduced the cell viability and induced apoptosis in HL-60 and WEHI-3 leukemia cells. Following exposure of cells to 30 nM of ITR-284, there is a time-dependent decrease in the mitochondrial membrane potential (DeltaPsi(m)) and an increase in the reactive oxygen species (ROS). ITR-284 treatment also caused a time-dependent increase of Fas/CD95, cytosolic cytochrome c, cytosolic active form of caspase-8/-9/-3, cytosolic Apaf-1 and Bax, and the decrease of Bcl-2. However, the ITR-284-induced caspase-8/-9 and -3 activities can be blocked by pan-caspase inhibitor (Z-VAD-FMK). In addition, the anti-leukemia effects of ITR-284 in vivo were further evaluated in BALB/c mice inoculated with WEHI-3 cells. Orally treatment with ITR-284 (2 and 10mg/kg/alternate day for 7 times) increased the survival rate and prevented the loss of body weight in leukemia mice. The enlargement of spleen and infiltration of immature myeloblastic cells into spleen red pulp were significantly reduced in ITR-284-treated mice compared with control mice. Moreover, ITR-284 application can enhance the anti-leukemia effect of all-trans retinoic acid (ATRA). These results revealed that ITR-284 acted against both HL-60 and WEHI-3 in vitrovia both intrinsic and extrinsic apoptotic signaling pathways, and exhibited an anti-leukemic effect in a WEHI-3 orthotopic mice model of leukemia.