Yuan-Chiang Chung

The effect of Longan seed polyphenols on colorectal carcinoma cells.

Eur J Clin Invest 2010; 40 (8): 713–721

Anti-interleukin-6 receptor antibody inhibits the progression in human colon carcinoma cells

Eur J Clin Invest 2011; 41 (3): 277–284

Induction of Apoptosis and Cell Cycle Arrest in Human Colorectal Carcinoma by Litchi Seed Extract

The Litchi (Litchi chinensis) fruit products possess rich amounts of flavanoids and proanthocyanidins. Its pericarp has been shown to inhibit breast and liver cancer cell growth. However, the anticolorectal cancer effect of Litchi seed extract has not yet been reported. In this study, the effects of polyphenol-rich Litchi seed ethanol extract (LCSP) on the proliferation, cell cycle, and apoptosis of two colorectal cancer cell lines Colo320DM and SW480 were examined. The results demonstrated that LCSP significantly induced apoptotic cell death in a dose-dependent manner and arrested cell cycle in G2/M in colorectal carcinoma cells. LCSP also suppressed cyclins and elevated the Bax : Bcl-2 ratio and caspase 3 activity. This study provides in vitro evidence that LCSP serves as a potential chemopreventive agent for colorectal cancer.

Grape-seed procyanidins inhibit the in vitro growth and invasion of pancreatic carcinoma cells.

Objectives Grape-seed procyanidins (GSPs) can inhibit cell proliferation and invasiveness in various human cancers. However, the effect of GSP on pancreatic carcinoma cells has not been investigated. Methods Pancreatic carcinoma cell lines MIA PaCa-2 and BxPC-3 treated with GSP were assessed for viability by trypan blue exclusion, for cell cycle distribution by flow cytometry, for increased apoptosis by annexin V labeling, for their adhesion and invasion potential by evaluating their ability to penetrate through a matrix gel–coated Boyden chamber, and for changes in the levels of proteins involved in cellular events by immunoblotting. Results Grape-seed procyanidin inhibited MIA PaCa-2 and BxPC-3 proliferation in a dose-dependent manner and induced G1-phase arrest of the cell cycle in BxPC-3 or mitochondria-mediated apoptosis in MIA PaCa-2. Grape-seed procyanidin also inhibited the adhesion and invasion potential of both cell lines in a dose-dependent manner, which are associated with the suppression of metalloproteases matrix metalloproteinase 9 or 2 (MMP-9 or -2) expression. Conclusions Grape-seed procyanidin inhibited the proliferation of pancreatic carcinoma cells by cell cycle blockage or apoptotic induction. The invasiveness was also suppressed by GSP through down-regulation of MMP-2 or MMP-9 in pancreatic carcinoma cells. Grape-seed procyanidin is a potential chemotherapeutic or preventive agent for pancreatic carcinoma.

Longan flower extract inhibits the growth of colorectal carcinoma.

Longan flower extract (LFE) has been shown to exhibit free radical scavenging ability and anti-inflammatory effects. However, the effect of LFE treatment on the growth of colorectal cancer cells has not been evaluated. This study investigated the effect of LFE on two colorectal cancer cell lines, SW-480 and Colo 320DM, and the possible mechanisms involved. LFE-treated cells were assessed for viability by trypan blue exclusion, for in vitro tumorigenesis by seeding cells in soft agar to allow anchorage independent growth, for cell cycle distribution by flow cytometry, for loss of mitochondrial membrane potential by rhodamine 123 staining, for increased apoptosis by DNA fragmentation assay, and for changes in the levels of proteins involved in cell cycle control and apoptosis by immunoblotting. LFE (25–400 μg/ml) could inhibit proliferation in a dose- and time-dependent manner. The cell cycle of both LFE-treated cell lines showed obvious S phase block. Western blotting further showed the S phase block in these two cell lines was mainly due to cyclin E accumulation and cyclin A decrease. LFE treatment increased rhodamine 123-negative cells and DNA fragmentation in Colo 320DM cells but not in SW480 cells. Increased levels of the apoptosis activation protein, caspase 3, were also found in Colo 320DM cells. The activation of caspase 3 in LFE-treated SW480 cells was not significant. The caspase 3 activation in Colo 320DM cells by LFE was mediated by the suppression of Bcl-2 protein levels. LFE treatment could inhibit the proliferation and malignancy of colorectal cancer cell lines and was associated with S phase block of the cell cycle. An apoptotic mechanism induced by LFE involving a loss of mitochondrial membrane potential and caspase 3 activation was found in Colo 320DM cells but not in SW480 cells. The results of this study indicate that LFE has potential to be developed as a novel functional food or chemopreventive agent for colorectal cancer.

Potential roles of longan flower and seed extracts for anti-cancer

Polyphenol-rich plants are known to possess benefits to human health. Recent studies have revealed that many Traditional Chinese Medicines (TCMs) are rich sources of polyphenols and exhibit antioxidant and anti-inflammatory activities, and these TCMs have been shown experimentally to overcome some chronic diseases, including cancer. Longan flowers and seeds, two TCMs traditionally used for relieving pain and urinary diseases, have been revealed in our recent reports and other studies to possess rich amounts of polyphenolic species and exhibit strong anti-oxidant activity, and these could be applied for the treatment of diabetes and cancer. Herein, we review the recent findings regarding the benefits of these two TCMs in the treatment of human cancer and the possible cellular and molecular mechanisms of both substances.

Litchi seed extract inhibits epidermal growth factor receptor signaling and growth of Two Non-small cell lung carcinoma cells.

BackgroundLitchi seeds possess rich amounts of phenolics and have been shown to inhibit proliferation of several types of cancer cells. However, the suppression of EGFR signaling in non-small cell lung cancer (NSCLC) by litchi seed extract (LCSE) has not been fully understood.MethodsIn this study, the effects of LCSE on EGFR signaling, cell proliferation, the cell cycle and apoptosis in A549 adenocarcinoma cells and NCI- H661 large-cell carcinoma cells were examined.ResultsThe results demonstrated that LCSE potently reduced the number of cancer cells and induced growth inhibition, cell-cycle arrest in the G1 or G2/M phase, and apoptotic death in the cellular experiment. Only low cytotoxicity effect was noted in normal lung MRC-5 cells. LCSE also suppressed cyclins and Bcl-2 and elevated Kip1/p27, Bax and caspase 8, 9 and 3 activities, which are closely associated with the downregulation of EGFR and its downstream Akt and Erk-1/-2 signaling.ConclusionThe results implied that LCSE suppressed EGFR signaling and inhibited NSCLC cell growth. This study provided in vitro evidence that LCSE could serve as a potential agent for the adjuvant treatment of NSCLC.

Longan flower proanthocyanidins induce apoptosis in HT-29 colorectal carcinoma spheroids

Aim of Study: Proanthocyanidin-rich longan flower extract (LFP) has been previously shown to inhibit the proliferation and anchorage-independent growth in soft agar of two colorectal carcinoma (CRC) cells in vitro. In this report, we further examined the effects of LFP in a CRC spheroid model. Materials and Methods: A liquid-overlay assay employing HT-29 spheroids was used to evaluate the effects of LFP on cancer cell tumorigenesis, viability, and apoptosis. Associated effects on signaling path ways (epidermal growth factor receptor [EGFR], Akt) and apoptotic regulators were measured using Western blot. Results: Treatment with LFP up to 200 μg/ml inhibited tumor growth in a dose-dependent manner and induced prominent apoptosis as measured by annexin V staining. Cells treated with LFP showed decreased EGFR and Akt phosphorylation with decreased expression of B-cell lymphoma 2. Conclusion: The ability of LFP to induce apoptosis in CRC spheroids warrants further investigation of its composition and identification of tumor-active components.