Displaying all 6 publications

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  1. Lee WL, Huang JY, Shyur LF
    Oxid Med Cell Longev, 2013;2013:925804.
    PMID: 24454991 DOI: 10.1155/2013/925804
    Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The "double-edged sword" role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.
  2. Lee HM, Patel V, Shyur LF, Lee WL
    Phytomedicine, 2016 Nov 15;23(12):1535-1544.
    PMID: 27765374 DOI: 10.1016/j.phymed.2016.09.005
    BACKGROUND: Oral cancer is the sixth most common cancer worldwide and 90% of oral malignancies are caused by oral squamous cell carcinoma (OSCC). Curcumin, a phytocompound derived from turmeric (Curcuma longa) was observed to have anti-cancer activity which can be developed as an alternative treatment option for OSCC. However, OSCC cells with various clinical-pathological features respond differentially to curcumin treatment.

    HYPOTHESIS: Intracellular copper levels have been reported to correlate with tumor pathogenesis and affect the sensitivity of cancer cells to cytotoxic chemotherapy. We hypothesized that intracellular copper levels may affect the sensitivity of oral cancer cells to curcumin.

    METHODS: We analysed the correlation between intracellular copper levels and response to curcumin treatment in a panel of OSCC cell lines derived from oral cancer patients. Exogenous copper was supplemented in curcumin insensitive cell lines to observe the effect of copper on curcumin-mediated inhibition of cell viability and migration, as well as induction of oxidative stress and apoptosis. Protein markers of cell migration and oxidative stress were also analysed using Western blotting.

    RESULTS: Concentrations of curcumin which inhibited 50% OSCC cell viability (IC50) was reduced up to 5 times in the presence of 250 µM copper. Increased copper level in curcumin-treated OSCC cells was accompanied by the induction of intracellular ROS and increased level of Nrf2 which regulates oxidative stress responses in cells. Supplemental copper also inhibited migration of curcumin-treated cells with enhanced level of E-cadherin and decreased vimentin, indications of suppressed epithelial-mesenchymal transition. Early apoptosis was observed in combined treatment but not in treatment with curcumin or copper alone.

    CONCLUSION: Supplement of copper significantly enhanced the inhibitory effect of curcumin treatment on migration and viability of oral cancer cells. Together, these findings provide molecular insight into the role of copper in overcoming insensitivity of oral cancer cells to curcumin treatment, suggesting a new strategy for cancer therapy.

  3. Ho YF, Yajit NLM, Shiau JY, Malek SNA, Shyur LF, Karsani SA
    Appl Biochem Biotechnol, 2023 Nov;195(11):6867-6880.
    PMID: 36947367 DOI: 10.1007/s12010-023-04384-2
    Our previous findings demonstrated that Helichrysetin possessed promising anti-cancer activity. It was able to induce apoptosis in the A549 cell line. However, its mechanism of action is unknown. The present study aimed to unravel possible underlying molecular mechanisms of helichrysetin-induced apoptosis in A549 (human lung carcinoma) cells using comparative quantitative proteomics (iTRAQ labeled), followed by an exhaustive bioinformatics analysis. Our results suggested that DNA damage response (DDR) and cell cycle arrest were responsible for lung cancer cell death with helichrysetin treatment. Among proteins that changed in abundance were Nrf2 and HMOX1. They are oxidative stress-related proteins and were increased in abundance. BRAT1 was also increased in abundance, suggesting an increase in DNA damage repair, indicating the occurrence of DNA damage due to oxidative stress. However, several essential DDR downstream proteins such as p-ATM, BRCA1, FANCD2, and Rb1 that would further increase DNA damage were found to be dramatically decreased in relative abundance. Cell cycle-related proteins, p53, p21, and cyclin D1, were increased while cyclin A, cyclin E, and cdk2 were decreased. This is predicted to facilitate S-phase arrest. Furthermore, excessive DNA damage and prolonged arrest would in turn result in the induction of mitochondrial-mediated apoptosis. Based on these observations, we postulate that the effects of helichrysetin were in part via the suppression of DNA damage response which led to DNA damage and prolonged cell cycle arrest. Subsequently, this event initiated mitochondrial-mediated apoptosis in A549 lung cancer cells.
  4. Nakagawa-Goto K, Chen JY, Cheng YT, Lee WL, Takeya M, Saito Y, et al.
    Mol Oncol, 2016 06;10(6):921-37.
    PMID: 27055598 DOI: 10.1016/j.molonc.2016.03.002
    Triple-negative breast cancer (TNBC) is associated with high grade, metastatic phenotype, younger patient age, and poor prognosis. The discovery of an effective anti-TNBC agent has been a challenge in oncology. In this study, fifty-eight ester derivatives (DETDs) with a novel sesquiterpene dilactone skeleton were organically synthesized from a bioactive natural product deoxyelephantopin (DET). Among them, DETD-35 showed potent antiproliferative activities against a panel of breast cancer cell lines including TNBC cell line MDA-MB-231, without inhibiting normal mammary cells M10. DETD-35 exhibited a better effect than parental DET on inhibiting migration, invasion, and motility of MDA-MB-231 cells in a concentration-dependent manner. Comparative study of DETD-35, DET and chemotherapeutic drug paclitaxel (PTX) showed that PTX mainly caused a typical time-dependent G2/M cell-cycle arrest, while DETD-35 or DET treatment induced cell apoptosis. In vivo efficacy of DETD-35 was evaluated using a lung metastatic MDA-MB-231 xenograft mouse model. DETD-35 significantly suppressed metastatic pulmonary foci information along with the expression level of VEGF and COX-2 in SCID mice. DETD-35 also showed a synergistic antitumor effect with PTX in vitro and in vivo. This study suggests that the novel compound DETD-35 may have a potential to be further developed into a therapeutic or adjuvant agent for chemotherapy against metastatic TNBC.
  5. Shang KM, Su TH, Lee WL, Hsiao WW, Chiou CY, Ho BY, et al.
    Phytomedicine, 2017 Jan 15;24:39-48.
    PMID: 28160860 DOI: 10.1016/j.phymed.2016.11.006
    INTRODUCTION: Tamoxifen, an anti-oestrogenic drug for estrogen receptor positive (ER+) breast cancer, was observed to stimulate tumor growth or drug resistance in patients. Antrodia cinnamomea (AC), a precious medicinal fungus has been traditionally used as a folk remedy for cancers in Asian countries. The objective of this study was to investigate the bioefficacy and the underlying molecular mechanisms of the AC fruiting bodies extracts (AC-3E) against human ER+ T47D breast cancer cells, and compare the effect with that of tamoxifen.

    METHODS: Cell proliferation, migration, TUNEL assay, western blotting, time-lapse confocal microscopy analyses, chorioallantoic membrane assay, and a xenograft BALB/c nude mouse system were used in this study. Chemical fingerprinting of AC-3E was established using LC-MS.

    RESULTS: AC-3E attenuated T47D breast cancer cell activity by deregulating the PI3K/Akt/mTOR signaling pathway and key cell-cycle mediators, and inducing apoptosis. AC-3E also effectively inhibited tube-like structures of endothelial cells, blood vessel branching and microvessel formation ex vivo and in vivo. Significant preventive and therapeutic effects against T47D mammary tumor growth of AC-3E was observed comparable or superior to tamoxifen treatment in xenograft BALB/c nude mice. Dehydroeburicoic acid (2) was characterized as the main chemical constituent in AC-3E against breast cancer.

    CONCLUSION: This study suggests that AC-3E extracts can be employed as a double-barreled approach to treat human ER+ breast cancer by attacking both cancer cells and tumor-associated blood vessel cells.

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