Jing Nan Lu

Characterization of a profile of the anthocyanins isolated from Vitis coignetiae Pulliat and their anti-invasive activity on HT-29 human colon cancer cells.

We isolated anthocyanins from fruits of Vitis coignetiae Pulliat, characterized the anthocyanin profile, and investigated the anti-invasive effects of the anthocyanins on human colon cancer cells. The anthocyanins inhibited cell invasion in a dose-dependent manner, as measured by Matrigel invasion assays, by suppression of matrix metalloproteinase (MMP)-2 and MMP-9 expression. The anti-invasive activity of the anthocyanins was associated with modulation of constitutive nuclear factor kappaB (NF-kappaB) activation. The activation of NF-kappaB triggered by tumor necrosis factor-alpha was also inhibited by the anthocyanins through suppression IkappaBalpha phosphorylation. AIMs inhibited the expression of NF-kappaB-regulated proteins. In conclusion, this study suggested that the anthocyanins isolated from fruits of V. coignetiae Pulliat should have anti-invasive activities on human colon cancer cells and the activities should be related to the inhibition of NF-kappaB-regulated proteins such as MMP-2 and MMP-9 expression through the inhibition of NF-kappaB activation.

Anti-invasive activities of anthocyanins through modulation of tight junctions and suppression of matrix metalloproteinase activities in HCT-116 human colon carcinoma cells

Claudins are a family of proteins that are the most important components of the tight junctions. Recently it has been reported that these proteins are overexpressed in cancers and there is a positive correlation between suppression of the expression of these proteins and anti-invasive activity. Matrix metalloproteinases (MMPs) have been implicated as important mediators in cancer invasion. Here, we investigated the effects of anthocyanins on tight junctions (TJs) and the expression of claudins as well as MMPs. The inhibitory effects of the anthocyanins on cell proliferation, motility and invasiveness were found to be associated with tightening TJs, which was demonstrated by an increase in transepithelial electrical resistance (TER). The expression of claudin proteins was suppressed by anthocyanins. Furthermore, the activities of MMP-2 and -9 were dose-dependently suppressed by anthocyanin treatment. These effects were related to activation of 38-MAPK and suppression of the PI3K/Akt pathway in HCT-116 human colon cancer cells.

Anti-invasive activity of anthocyanins isolated from Vitis coignetiae in human hepatocarcinoma cells.

We investigated anti-invasive effects of the anthocyanins from fruits of Vitis coignetiae Pulliat (known as meoru in Korea) on human hepatoma Hep3B cells. The anthocyanins inhibited cell invasion in a dose-dependent manner as measured by Matrigel (BD Biosciences, San Jose, CA, USA) invasion assays. They also inhibited expression of matrix metalloproteinase (MMP)-2 and MMP-9 and activation of nuclear factor kappaB (NF-kappaB) stimulated by tumor necrosis factor alpha. Taken together, the results of this study indicate that the anthocyanins isolated from fruits of V. coignetiae Pulliat have anti-invasive effects on human hepatoma Hep3B cells and inhibit MMP-2 and MMP-9 gene expression at least in part through the inhibition of NF-kappaB activation.

p53 restoration can overcome cisplatin resistance through inhibition of Akt as well as induction of Bax

Cisplatin (CDDP) is a chemotherapeutic agent that is widely used to treat many cancers. However, initial resistance to CDDP is a serious problem in treating cancers. In this study, in order to develop an approach to overcome resistance to CDDP, we investigated the difference in apoptotic processes between CDDP-sensitive cells and CDDP-resistant cells. By screening with CDDP sensitivity tests, we chose SNU-16 cells which are relatively resistant to CDDP, and SNU-1 cells which are sensitive to CDDP. We compared the difference between the two cell lines focusing on apoptosis. CDDP-induced reactive oxygen species (ROS) generation significantly induced loss of mitochondrial membrane potential (MMP, ∆Ψm) in SNU-1 cells, but not in SNU-16 cells. In addition, the ratio of Bax to Bcl-2 was increased by CDDP treatment in SNU-1 cells, but not in SNU-16 cells. To augment the loss of MMP, ∆Ψm in SNU-16, we inhibited Akt activity of SNU-16 cells to suppress their anti-apoptotic activity. The inhibition of Akt activity led to suppression of the anti-apoptotic protein XIAP. Akt inhibition slightly enhanced CDDP-induced apoptosis in SNU-16 cells. In addition, we enhanced pro-apoptotic activity by transfecting the cells with the wild-type p53 gene. The induction of wild-type p53 can enhance CDDP-induced apoptosis not only by inducing Bax protein but also by suppressing anti-apoptotic proteins through inhibition of Akt. In conclusion, this study suggests that the primary contributor to resistance to CDDP in SNU-16 cells may well be a failure of induction of apoptosis due to a lack of induction of pro-apoptotic proteins rather than suppression of anti-apoptotic proteins, and that restoration of p53 function can overcome the resistance to CDDP not only by augmenting the pro-apoptotic drive through p53-mediated transcriptional activation but also by inhibiting the anti-apoptotic drive through inhibition of Akt activity.

Citrus aurantium L. exhibits apoptotic effects on U937 human leukemia cells partly through inhibition of Akt

Citrus fruits have been used as edible fruits and a traditional medicine since ancient times. In particular, the peels of immature citrus fruits are frequently prescribed in concert with other support herbs for many types of disease including cancer. We investigated the anti-proliferative activity of the peels of Citrus aurantium L. along with their effects on apoptosis. We prepared crude methanol extracts of the peels of Citrus aurantium L. (CMEs) and performed experiments using U937 human leukemia cells. The growth of U937 cells was inhibited by CME treatment in a dose-dependent manner, and CME induced caspase-dependent apoptosis. CME inhibited the expression of XIAP and Bcl-xL which are anti-apoptotic proteins. CME inhibited Akt activity in a dose-dependent manner. The apoptotic activity of CME was significantly attenuated by Akt augmentation. In conclusion, this study suggested that CME should induce caspase-dependent apoptosis at least in part through Akt inhibition, providing evidence that CMEs have anticancer activity on human leukemia cells.

The inhibitory effect of anthocyanins on Akt on invasion and epithelial-mesenchymal transition is not associated with the anti-EGFR effect of the anthocyanins

Evidence suggests that anthocyanins inhibit EGFR and Akt activity. However, it is still unknown whether the inhibitory effect of anthocyanins on Akt is associated with the anti-EGFR effect. The effect of anthocyanins on epithelial-mesenchymal transition (EMT) has not been extensively studied. Therefore, we investigated the effects of anthocyanins from fruits of Vitis coignetiae Pulliat (AIMs) on EGF-induced EMT and the underlying molecular mechanisms. AIMs suppressed the invasion of A549 cells in a dose-dependent manner. AIMs inhibited the phosphorylation of Akt and EGFR, but the inhibitory effect on Akt was not derived from EGFR. EGF re-induced Akt phosphorylation at Thr308 in the AIM-treated cells, but not Akt phosphorylation at Ser473. AIMs also inhibited EMT of cancer cells. AIMs inhibited glycogen synthase kinase-3β phosphorylation and β-catenin expression that are invovled in EMT. We confirmed these findings with transforming growth factor (TGF)-β. In conclusion, these data suggest that the inhibitory effect of AIMs on Akt activity is independent of EGFR, and that AIMs suppressed invasion and migration at least in part by suppressing EMT by inhibiting Akt activity as well as EGFR. This study provides evidence that AIMs may have anticancer effects on human cancer cells.

Tetraarsenic Hexoxide Induces Beclin-1-Induced Autophagic Cell Death as well as Caspase-Dependent Apoptosis in U937 Human Leukemic Cells

Tetraarsenic hexaoxide (As4O6) has been used in Korean folk remedy for the treatment of cancer since the late 1980s, and arsenic trioxide (As2O3) is currently used as a chemotherapeutic agent. However, evidence suggests that As4O6-induced cell death pathway was different from that of As2O3. Besides, the anticancer effects and mechanisms of As4O6 are not fully understood. Therefore, we investigated the anticancer activities of As4O6 on apoptosis and autophagy in U937 human leukemic cells. The growth of U937 cells was inhibited by As4O6 treatment in a dose- and a time-dependent manner, and IC50 for As4O6 was less than 2 μM. As4O6 induced caspase-dependent apoptosis and Beclin-1-induced autophagy, both of which were significantly attenuated by Bcl-2 augmentation and N-acetylcysteine (NAC) treatment. This study suggests that As4O6 should induce Beclin-1-induced autophagic cell death as well as caspase-dependent apoptosis and that it might be a promising agent for the treatment of leukemia.

Anthocyanins from Vitis coignetiae Pulliat Inhibit Cancer Invasion and Epithelial-Mesenchymal Transition, but These Effects Can Be Attenuated by Tumor Necrosis Factor in Human Uterine Cervical Cancer HeLa Cells

Recently we have demonstrated that anthocyanins from fruits of Vitis coignetiae Pulliat (AIMs) have anticancer effects. Here, we investigate the effects of AIMs on cell proliferation and invasion as well as epithelial-mesenchymal transition (EMT) which have been linked to cancer metastasis in human uterine cervical cancer HeLa cells. AIMs inhibited the invasion of HeLa cells in a dose-dependent manner. AIMs inhibited MMP-9 expression in a dose-dependent manner. AIMs inhibited the motility of HeLa cells in a wound healing test. AIMs still suppressed NF-κB activation induced by TNF. AIMs also inhibited EMT in HeLa cells. AIMs suppressed vimentin, N-cadherin, and β-catenin expression and induced E-cadherin. AIMs also suppressed expression of β-catenin and Snail, which was regulated by GSK-3. These effects of AIMs were also limited in the HeLa cells treated with TNF. In conclusion, this study indicates that AIMs have anticancer effects by suppressing NF-κB-regulated genes and EMT, which relates to suppression of IκBα phosphorylation and GSK-3 activity, respectively. However, the effects of AIMs were attenuated in the TNF-high condition.

Tetraarsenic hexoxide induces G2/M arrest, apoptosis, and autophagy via PI3K/Akt suppression and p38 MAPK activation in SW620 human colon cancer cells

Tetraarsenic hexoxide (As4O6) has been used in Korean folk medicines for the treatment of cancer, however its anti-cancer mechanisms remain obscured. Here, this study investigated the anti-cancer effect of As4O6 on SW620 human colon cancer cells. As4O6 has showed a dose-dependent inhibition of SW620 cells proliferation. As4O6 significantly increased the sub-G1 and G2/M phase population, and Annexin V-positive cells in a dose-dependent manner. G2/M arrest was concomitant with augment of p21 and reduction in cyclin B1, cell division cycle 2 (cdc 2) expressions. Nuclear condensation, cleaved nuclei and poly (adenosine diphosphate‑ribose) polymerase (PARP) activation were also observed in As4O6-treated SW620 cells. As4O6 induced depolarization of mitochondrial membrane potential (MMP, ΔΨm) but not reactive oxygen species (ROS) generation. Further, As4O6 increased death receptor 5 (DR5), not DR4 and suppressed the B‑cell lymphoma‑2 (Bcl-2) and X-linked inhibitor of apoptosis protein (XIAP) family proteins. As4O6 increased the formation of AVOs (lysosomes and autophagolysosomes) and promoted the conversion of microtubule-associated protein 1A/1B-light chain 3 (LC3)-I to LC3-II in a dose- and time- dependent manner. Interestingly, a specific phosphoinositide 3-kinase (PI3K)/Akt inhibitor (LY294002) augmented the As4O6 induced cell death; whereas p38 mitogen-activated protein kinases (p38 MAPK) inhibitor (SB203580) abrogated the cell death. Thus, the present study provides the first evidence that As4O6 induced G2/M arrest, apoptosis and autophagic cell death through PI3K/Akt and p38 MAPK pathways alteration in SW620 cells.

Anthocyanins From the Fruit of Vitis coignetiae Pulliat Potentiate the Cisplatin Activity by Inhibiting PI3K/Akt Signaling Pathways in Human Gastric Cancer Cells

Background: Cisplatin (cis-diaminedichloroplatinum, CDDP) is a widely used chemotherapeutic agent for the treatment of many cancers. However, initial resistance to CDDP is a serious problem in treating these cancers. Vitis coignetiae Pulliat (Meoru in Korea) have shown anti-nuclear factor kappa B and anti-epidermal growth factor receptor activities in cancer cells. Methods: In this study, in order to seeking an approach to increase the anti-cancer effects of CDDP with natural products. Here, we investigated anthocyanins isolated from Vitis coignetiae Pulliat (anthocyanidins isolated from meoru, AIMs) can enhance anti-cancer effects of cisplatin (CDDP) in stomach cancer cells. The cell viability of SNU-1 and SNU-16 cells after treated with AIMs and CDDP were analyzed by MTT assay. The expressions of Akt and X-linked inhibitor of apoptosis protein (XIAP) proteins were examined by western blot in AIMs- and CDDP-treated cells. Results: We found that AIMs enhanced anticancer effects of CDDP, which activity was additive but not synergistic. AIMs suppressed Akt activity of the cancer cells activated by CDDP. AIMs also suppressed in XIAP an anti-apoptotic protein. Conclusions: This study suggests that the anthocyanins isolated from fruits of Vitis coignetiae Pulliat enhanced anti-cancer effects of CDDP by inhibiting Akt activity activated by CDDP.