Shikonin inhibits proliferation and induces apoptosis in glioma cells via downregulation of CD147.

Shikonin, a traditional Chinese medicine, has been identified as being capable of inducing apoptosis in various tumors, including glioma, and is thus considered to be a promising therapeutic agent for tumor therapy. However, little is known about the molecular mechanism of shikonin in glioma. The present study investigated the influence of shikonin on the proliferation and apoptosis of glioma cells U251 and U87MG and explored the potential molecular mechanisms. It was identified that shikonin was able to induce apoptosis in human glioma cells in a time­ and dose­dependent manner, and a decreased expression level of cluster of differentiation (CD)147 was observed in shikonin­treated U251 and U87MG cells. Knockdown of CD147 inhibited U251 and U87MG cell growth, whereas CD147 overexpression enhanced cell growth and decreased shikonin­induced apoptosis. Additionally, an increased expression level of CD147 suppressed the elevated production of reactive oxygen species and mitochondrial membrane potential levels induced by shikonin. The data indicated that shikonin­induced apoptosis in glioma cells was associated with the downregulation of CD147 and the upregulation of oxidative stress. CD147 may be an optional target of shikonin­induced cell apoptosis in glioma cells.

Apple polysaccharide reduces NF-Kb mediated colitis-associated colon carcinogenesis.

Nuclear factor-kappa B (NF-κB) is an important molecule in mediating inflammatory colitis, which can lead to colorectal cancer (CRC). The aim of this study was to evaluate the chemopreventive efficacy of apple polysaccharide extract (AP) in inhibiting NF-κB-mediated inflammation pathways in CRC. We evaluated AP in vitro in HT-29 and SW620 human CRC cells. We also used the azoxymethane and dextran sodium sulphate (AOM/DSS) model to induce colon carcinogenesis in vivo. The chemoprotective effects of AP were assessed using Western blot, immunofluorescence assay, real-time PCR, electrophoretic mobility shift assay, and flow cytometry. AP reduced AOM/DSS-associated toxicities, prevented carcinogenesis, and decreased the expression of TLR4, MD2, MyD88, TRAM, TRIF-related adapter molecule, interferon-ß, tumor necrosis factor-α, and interleukin-6. The protective effects of AP may be related to the inhibition of TLR4/MD2-mediated signaling, including MyD88 and TRIF, as well as the inhibition of NF-κB-mediated inflammatory signaling pathways. Therefore, AP could be used in combination therapy for the prevention of colitis-associated colon cancer.

Modified apple polysaccharides suppress the migration and invasion of colorectal cancer cells induced by lipopolysaccharide.

Metastasis is the major cause of death in colorectal cancer (CRC). In colitis-associated carcinogenesis, the activation of nuclear factor-κB (NF-κB) occurs via lipopolysaccharide (LPS) binding to the toll-like receptor 4 (TLR4). The LPS/TLR4/NF-κB pathway contributes to the development and metastasis of colitis-associated colon cancer. In the present study, we hypothesized that an extracted modified Fuji apple polysaccharide (MAP) would alter the LPS/TLR4/NF-κB pathway. Thus, we evaluated the effect of MAP in vitro on the LPS/TLR4/NF-κB pathway in CRC cells (HT-29 and SW620 cells). The results suggest that (i) MAP competed with LPS for binding to TLR4 to reduce LPS-induced NF-κB expression and (ii) MAP suppressed the nuclear translocation of NF-κB p65. MAP significantly decreased LPS-induced expression of TLR4, cyclooxygenase-2, matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 2, inducible nitric oxide synthase, and prostaglandin E2, and it increased the protein expression of the inhibitor of κBα and NF-κB p65 in cytoplasm when it was given in combination with LPS. These results indicate that MAP suppressed LPS-induced migration and invasiveness of CRC cells by targeting the LPS/TLR4/NF-κB pathway. Therefore, we propose that MAP has potential for the clinical prevention of CRC cell metastasis.

Apple polysaccharides induce apoptosis in colorectal cancer cells.

Certain components of apples have been shown to prevent cancer growth and impede cancer progression. We hypothesized that extracted apple polysaccharides (APs) might, therefore, have anticancer effects, through a mechanism involving the induction of apoptosis in cancer cells, partly via the NF-κB pathway. Two human colorectal cancer (CRC) cell lines, HT-29 and SW620, were exposed to different concentrations of APs (0.01, 0.1 or 1 mg/ml). Cell apoptosis was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay by flow cytometry and incorporation of 5'-bromodeoxyuridine (BrdU) into DNA to identify the proliferating cell fraction, using fluorescence microscopy in vitro. The protein levels of NF-κB/p65, I-κBα, pI-κBα, Bax, Bcl-xl and Bcl-2 were evaluated by western blotting. The target sites of APs on CRC cells were assessed by flow cytometry. At concentrations of 0.1 and 1 mg/ml, APs showed apoptosis-inducing effects, increased expressions of Bax, nuclear p65 and cytoplasmic pI-κBα, and decreased expressions of Bcl-2, Bcl-xl and cytoplasmic I-κBα. APs induced apoptosis by slightly activating the NF-κB pathway; the AP target site could be the Toll-like receptor 4 on the cell membrane. These results demonstrate the potential of APs as agents for clinical prevention and treatment of CRC.