iridoids and Adenocarcinoma

Phosphatase PTP1B has become a therapeutic target for the treatment of type 2-diabetes, whereas recent studies have revealed that PTP1B plays a pivotal role in pathophysiology and development of breast cancer. Oleuropein is a natural, phenolic compound with anticancer activity. The aim of this study was to address the question whether PTP1B constitutes a target for oleuropein in breast cancer MCF-7 cells. The cellular MCF-7 breast cancer model was used in the study. The experiments were performed using cellular viability tests, Elisa assays, immunoprecipitation, flow cytometry analyses and computer modelling. Herein, we evidenced that the reduced activity of phosphatase PTP1B after treatment with oleuropein is strictly correlated with decreased MCF-7 cellular viability and cell cycle arrest. These results provide new insight into further research on oleuropein and possible role of the compound in adjuvant treatment of breast cancer.

Topics: Adenocarcinoma; Antineoplastic Agents; Breast Neoplasms; Cell Proliferation; Cell Survival; Humans; Iridoid Glucosides; Iridoids; MCF-7 Cells; Molecular Dynamics Simulation; Protein Tyrosine Phosphatase, Non-Receptor Type 1

Distinct metastasis is one of the main causes of breast cancer (BC)-related mortality and epithelial-mesenchymal transition (EMT) is a primary step in metastasis dissemination. On the other hand, doxorubicin (DOX) is an effective chemotherapeutic agent against BC; unfortunately, its clinical use is limited by dose-dependent side effects. Therefore, extensive efforts have been dedicated to suppressing metastasis of BC and also to overcome DOX side effects together with keeping its antitumor efficacy. Studies supported the role of oleuropein (OLEU) in reducing DOX-induced side effects besides its antitumor actions. In this study, the antimigratory effect of OLEU was assessed and real-time PCR (RT-PCR) was used to detect OLEU effect on the expression level of EMT markers, in MCF-7 cells. The cytotoxic effect of OLEU and DOX was assessed by MTT assay, whereas the ratio of apoptosis was investigated by flow cytometry. The results showed that migration ability of MCF-7 cells remarkably decreased in OLEU treated group and RT-PCR results showed that OLEU may exert its antimigratory action by suppressing EMT through downregulation of sirtuin1 (SIRT1). Also, the results indicated that both OLEU and DOX were cytotoxic to MCF-7 cells, whereas DOX-OLEU cotreatment led to additive cytotoxicity and apoptosis rate. This study provides evidence regarding the suppressive role of OLEU on MCF-7 cells migration ability through suppression of EMT, and for the first time, it was proposed that SIRT1 downregulation can be involved in the OLEU antimigratory effect. Also, the findings demonstrated that OLEU can reduce DOX-induced side effects by reducing its effective dose.

Topics: Adenocarcinoma; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Biomarkers, Tumor; Breast Neoplasms; Cell Movement; Down-Regulation; Doxorubicin; Drug Synergism; Epithelial-Mesenchymal Transition; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Iridoid Glucosides; Iridoids; MCF-7 Cells; Neoplasm Invasiveness; Signal Transduction; Sirtuin 1

Roles of dietary phytochemicals in cancer chemoprevention via induction of nuclear factor-erythroid-2-related factor 2 (Nrf2)-mediated antioxidant enzymes have been well established in a number of studies. In this study, FACS analysis was used to reveal that the intracellular reactive oxygen species level decreased at 0-25 μM of genipin treatment. Furthermore, immunofluorescence analysis and Western blotting were used to demonstrate that genipin treatment resulted in the upregulation and nuclear translocation of Nrf2, as well as upregulation of gastrointestinal glutathione peroxidase. Finally, we found that C-Jun-NH2-kinase (JNK) was also dose-dependently activated, where depleting JNK by using a biochemical inhibitor indicated that JNK was upstream of Nrf2. Interestingly, the antioxidant effects were limited to the treatment in the lower dosage of genipin, where higher dosage of genipin treatment resulted in the increased reactive oxygen species level and cytotoxicity. Thus, this study demonstrates for the first time that lower dosage of genipin results in the induction of JNK/Nrf2/ARE signaling pathway and protection from cell death.

Topics: Adenocarcinoma; Anticarcinogenic Agents; Cell Line, Tumor; Humans; Iridoids; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; NF-E2-Related Factor 2; Oxidative Stress; Reactive Oxygen Species; Response Elements; Stomach Neoplasms

Mitochondrial uncoupling protein 2 (UCP2) can moderate oxidative stress by favoring the influx of protons into the mitochondrial matrix, thus reducing electron leakage from respiratory chain and mitochondrial superoxide production. Here, we demonstrate that UCP2 inhibition by genipin or UCP2 siRNA strongly increases reactive oxygen species (ROS) production inhibiting pancreatic adenocarcinoma cell growth. We also show that UCP2 inhibition triggers ROS-dependent nuclear translocation of the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH), formation of autophagosomes, and the expression of the autophagy marker LC3-II. Consistently, UCP2 over-expression significantly reduces basal autophagy confirming the anti-autophagic role of UCP2. Furthermore, we demonstrate that autophagy induced by UCP2 inhibition determines a ROS-dependent cell death, as indicated by the apoptosis decrease in the presence of the autophagy inhibitors chloroquine (CQ) or 3-methyladenine (3-MA), or the radical scavenger NAC. Intriguingly, the autophagy induced by genipin is able to potentiate the autophagic cell death triggered by gemcitabine, the standard chemotherapeutic drug for pancreatic adenocarcinoma, supporting the development of an anti-cancer therapy based on UCP2 inhibition associated to standard chemotherapy. Our results demonstrate for the first time that UCP2 plays a role in autophagy regulation bringing new insights into mitochondrial uncoupling protein field.

Topics: Adenocarcinoma; Apoptosis; Autophagy; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cholagogues and Choleretics; Fluorescent Antibody Technique; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Ion Channels; Iridoids; Mitochondrial Proteins; Oxidative Stress; Pancreatic Neoplasms; Protein Transport; Reactive Oxygen Species; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Small Interfering; Uncoupling Protein 2

Crude phenolic extracts (PE) have been obtained from naturally bearing Spanish extra-virgin olive oil (EVOO) showing different polyphenol families such as secoiridoids, phenolic alcohols, lignans, and flavones. EVOO-derived complex phenols (especially from the Arbequina variety olive) have been shown to suppress cell growth of SW480 and HT29 human colon adenocarcinoma cell lines. Inhibition of proliferation by EVOO-PE Arbequina variety extract was accompanied by apoptosis in both colon-cancer-cell lines and a limited G₂M cell-cycle arrest in the case of SW480 cells. The metabolized compounds from EVOO-PE in culture medium and cytoplasm of both cell lines were analyzed using nano-liquid chromatography (nanoLC) coupled with electrospray ionization-time-of-flight-mass spectrometry (ESI-TOF-MS). The results showed many phenolic compounds and their metabolites both in the culture medium as well as in the cytoplasm. The main compounds identified from EVOO-PE were hydroxylated luteolin and decarboxymethyl oleuropein aglycone.

Topics: Adenocarcinoma; Antineoplastic Agents, Phytogenic; Apoptosis; Biotransformation; Cell Proliferation; Chromatography, Liquid; Colonic Neoplasms; Culture Media, Conditioned; Cytoplasm; Decarboxylation; G2 Phase Cell Cycle Checkpoints; HT29 Cells; Humans; Hydroxylation; Iridoid Glucosides; Iridoids; Luteolin; Metabolomics; Nanotechnology; Olive Oil; Phenols; Plant Oils; Pyrans; Spectrometry, Mass, Electrospray Ionization

The herb of Oldenlandia diffusa (Willd.) Roxb. (Family Rubiaceae) is well-known in Chinese folk medicine for the treatment of hepatitis and malignant tumors of the liver, lung and stomach. However, another herb of O. corymbosa (L.) Lam is also used interchangeably in South China for treating the same conditions. To compare the efficacy of the two herbs, the antiproliferative effect of their extracts and the antiangiogenic activity of their main constituents were appraised. The Sulforhodamine B (SRB) assay in human hepatoma HepG2 cells and human colon carcinoma CaCo2 cells and the zebrafish angiogenic model were used for this purpose. The results showed almost no antiproliferative effect of the methanol extracts from O. diffusa and O. corymbosa, while the chloroform extracts exhibited slightly antiproliferative effects. The main components had almost no effect on zebrafish angiogenic vessel formation at the concentrations tested. The results suggest that the mechanism of antitumor activity of O. diffusa may not be attributed to the antiproliferative and antiangiogenic effects.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Caco-2 Cells; Cell Line, Tumor; Cell Proliferation; Chromatography, High Pressure Liquid; Colonic Neoplasms; Cyclopentane Monoterpenes; Glucosides; Humans; Iridoids; Oldenlandia; Oleanolic Acid; Phytotherapy; Plant Extracts; Pyrans; Zebrafish