ginkgolic-acid and Breast-Neoplasms

Ginkgolic acids (GA), a group of alkyl phenols found in crude extracts of Ginkgo biloba leaves, are known to have anticancer activity, but their mode of action is not well understood. Our aim in this study was to investigate the anti-migratory activity of seven GA against breast cancer cells and to determine the molecular mechanism behind this activity. All seven GA and their mixture inhibited wound healing in MCF-7 and MDA-MB 231 breast cancer cells. None of the compounds nor the mixture showed cytotoxicity towards the two cell lines, if tested by the resazurin assay. C13:0 inhibited NF-κB activity in the HEK Blue Null 1 reporter cell line. Furthermore, C13:0 inhibited degradation of nuclear factor of κ-light polypeptide gene enhancer in B-cells inhibitor α (IκBα). Sumoylation assay revealed that GA inhibited sumoylation of NF-κB essential modulator (NEMO). Molecular docking on SUMO-activating enzyme E1 showed that the seven GA bound to the active adenylation site with high calculated affinities ranging from -10.28 to -12.27 kcal/mol. Quantitative RT-PCR using C15:0, C13:0 and the mixture showed a significant down-regulation of urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1), C-X-C chemokine receptor type 4 (CXCR4) and matrix metalloproteinase 9 (MMP-9). We conclude that GA revealed considerable anti-migratory activity at non-cytotoxic concentrations, indicating anti-metastatic activity with low toxicity. This effect can be explained by the inhibition of NEMO sumoylation leading to inhibition of IκBα degradation and consequently a reduction of NF-κB activity, leading to the down-regulation of metastasis related genes including uPA, PAI-1, CXCR4, and MMP-9.

Topics: Breast Neoplasms; Cell Line, Tumor; Cell Movement; Female; Gene Expression Regulation, Neoplastic; Humans; I-kappa B Kinase; Matrix Metalloproteinase 9; MCF-7 Cells; Models, Molecular; Molecular Docking Simulation; NF-kappa B; Plasminogen Activator Inhibitor 1; Receptors, CXCR4; Salicylates; Signal Transduction; Sumoylation; Urokinase-Type Plasminogen Activator

Breast cancer is genetically heterogeneous, and recent studies have underlined a prominent contribution of epigenetics to the development of this disease. To uncover new synthetic lethalities with known breast cancer oncogenes, we screened an epigenome-focused short hairpin RNA library on a panel of engineered breast epithelial cell lines. Here we report a selective interaction between the NOTCH1 signaling pathway and the SUMOylation cascade. Knockdown of the E2-conjugating enzyme UBC9 (UBE2I) as well as inhibition of the E1-activating complex SAE1/UBA2 using ginkgolic acid impairs the growth of NOTCH1-activated breast epithelial cells. We show that upon inhibition of SUMOylation NOTCH1-activated cells proceed slower through the cell cycle and ultimately enter apoptosis. Mechanistically, activation of NOTCH1 signaling depletes the pool of unconjugated small ubiquitin-like modifier 1 (SUMO1) and SUMO2/3 leading to increased sensitivity to perturbation of the SUMOylation cascade. Depletion of unconjugated SUMO correlates with sensitivity to inhibition of SUMOylation also in patient-derived breast cancer cell lines with constitutive NOTCH pathway activation. Our investigation suggests that SUMOylation cascade inhibitors should be further explored as targeted treatment for NOTCH-driven breast cancer.

Topics: Apoptosis; Blotting, Western; Breast Neoplasms; Cell Cycle; Cell Line; Cell Line, Tumor; Cell Proliferation; Coculture Techniques; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Microscopy, Fluorescence; Receptor, Notch1; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Salicylates; Signal Transduction; Small Ubiquitin-Related Modifier Proteins; SUMO-1 Protein; Sumoylation; Transcriptional Activation; Ubiquitin-Activating Enzymes; Ubiquitin-Conjugating Enzymes; Ubiquitins

Fatty acid synthase (FAS) has been proposed to be a new drug target for the development of anticancer agents because of the significant difference in expression of FAS between normal and tumour cells. Since a n-hexane-soluble extract from Ginkgo biloba was demonstrated to inhibit FAS activity in our preliminary test, we isolated active compounds from the n-hexane-soluble extract and evaluated their cytotoxic activity in human cancer cells. Three ginkgolic acids 1-3 isolated from the n-hexane-soluble extract inhibited the enzyme with IC(50) values 17.1, 9.2 and 10.5 µM, respectively, and they showed cytotoxic activity against MCF-7 (human breast adenocarcinoma), A549 (human lung adenocarcinoma) and HL-60 (human leukaemia) cells. Our findings suggest that alkylphenol derivatives might be a new type of FAS inhibitor with cytotoxic activity.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Antineoplastic Agents, Phytogenic; Breast Neoplasms; Cell Line, Tumor; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Fatty Acid Synthases; Female; Ginkgo biloba; Hexanes; HL-60 Cells; Humans; Inhibitory Concentration 50; Lung Neoplasms; Molecular Structure; Plant Extracts; Plant Leaves; Salicylates