Leaf Extract from European Olive (Olea europaea L.) Post-Transcriptionally Suppresses the Epithelial-Mesenchymal Transition and Sensitizes Gastric Cancer Cells to Chemotherapy.

The overall survival of patients with the advanced and recurrent gastric cancer (GC) remains unfavorable. In particular, this is due to cancer spreading and resistance to chemotherapy associated with the epithelial-mesenchymal transition (EMT) of tumor cells. EMT can be identified by the transcriptome profiling of GC for EMT markers. Indeed, analysis of the TCGA and GTEx databases (n = 408) and a cohort of GC patients (n = 43) revealed that expression of the CDH2 gene was significantly decreased in the tumors vs. non-tumor tissues and correlated with the overall survival of GC patients. Expression of the EMT-promoting transcription factors SNAIL and ZEB1 was significantly increased in GC. These data suggest that targeting the EMT might be an attractive therapeutic approach for patients with GC. Previously, we demonstrated a potent anti-cancer activity of the olive leaf extract (OLE). However, its effect on the EMT regulation in GC remained unknown. Here, we showed that OLE efficiently potentiated the inhibitory effect of the chemotherapeutic agents 5-fluorouracil (5-FU) and cisplatin (Cis) on the EMT and their pro-apoptotic activity, as was demonstrated by changes in the expression of the EMT markers (E- and N-cadherins, vimentin, claudin-1) in GC cells treated with the aforementioned chemotherapeutic agents in the presence of OLE. Thus, culturing GC cells with 5-FU + OLE or Cis + OLE attenuated the invasive properties of cancer cells. Importantly, upregulation of expression of the apoptotic markers (PARP cleaved form) and increase in the number of cells undergoing apoptosis (annexin V-positive) were observed for GC cells treated with a combination of OLE and 5-FU or Cis. Collectively, our data illustrate that OLE efficiently interferes with the EMT in GC cells and potentiates the pro-apoptotic activity of certain chemotherapeutic agents used for GC therapy.

Early-stage colon cancer with high MALAT1 expression is associated with the 5-Fluorouracil resistance and future metastasis.

BACKGROUND: This study aimed to investigate the role of long noncoding RNA (LncRNA) expression profiles to predict relapse and 5-FU response in patients with stage I/II colon cancer (CC). METHODS AND RESULTS: The expression level of 15 LncRNA was analyzed in stage I/II colon tumors of 126 CC patients. To confirm the findings in-vitro, 5FU-resistant HT29 cells were generated by subjecting HT-29 cells to the increasing concentrations of 5FU for 6 months. The 5FU resistance was observed in WST-1 and Annexin V analyses. The colony formation and wound healing assays were assessed to determine the metastatic properties of the cells. Expression levels of LncRNAs and mRNA of EMT-related genes were determined by RT-PCR. The role of LncRNA on metastasis and 5FU sensitivity were confirmed in pcDNA3.0-PTENP1 and si-MALAT1 expressed 5FU-resistant HT29 cell lineages. RESULTS: High MALAT1 (p = 0.0002) and low PTENP1 (p = 0.0044) expressions were significantly associated with 5-FU resistance and tumor relapse in stage I/II CC. The invasiveness and colony-forming characteristics of 5-FU-resistant cell lineages were higher as compared to the parent HT-29. Moreover, the expression of MALAT1 (p = 0.0009) was increased while the expression of PTENP1 (p = 0.0158) decreased in 5FU-resistant-HT-29 cells. Si-MALAT1 treatment increased cell sensitivity to 5FU, whereas it decreased invasive behaviors of 5 FU-resistant-HT-29 cells. CONCLUSION: MALAT1 may be a biomarker in predicting recurrence in early-stage CC. Our findings suggest that a cell-based therapy to target MALAT1 could be established for these patients to prevent metastasis and 5-FU resistance.

Olea europaea L. Leaf Extract Attenuates Temozolomide-Induced Senescence-Associated Secretion Phenotype in Glioblastoma.

Objectives: The purpose of this study was to investigate the effect of Olea europaea L. leaf extract (OLE) on senescence and senescence-associated secretory phenotype (SASP) caused by temozolomide (TMZ) in glioblastoma (GB). Materials and Methods: A senescence ß-galactosidase assay and a colony formation assay were used to determine the effects of OLE, TMZ, and OLE + TMZ on the cellular senescence and aggressiveness of GB cell lines T98G and U87MG. mRNA expression levels of p53, a senescence factor, interleukin (IL)-6, matrix metalloproteinases (MMP)-9, and nuclear factor kappa B1 (NF-κB1) as SASP factors and Bcl-2 and Bax as senolytic markers were assessed using quantitative reverse transcription-real-time polymerase chain reaction. Cells were double-stained with acridine orange and propidium iodide to observe the cell morphology. Results: TMZ increased the senescence rate of GB cells (p<0.001). Besides, OLE + TMZ reduced the proportion of senescent cells (p<0.001) and their capability to form colonies compared to TMZ-only-treated cells. Additionally, OLE + TMZ co-treatment elevated the mRNA expression levels of MMP-9, IL-6, NF-κB1, p53, and the Bax/Bcl-2 ratio compared to TMZ-only treatment. Especially in U87MG cells, involvement of OLE in TMZ treatments increased more than six times in the Bax/Bcl-2 ratio compared to TMZ-only, which induced the apoptosis-like morphological features (p<0.0001). Conclusion: Collectively, our findings presented the inhibitory effect of OLE on TMZ-mediated SASP-factor production in GB and, accordingly, its potential contribution to elongate the time of recurrence.

Olea europaea Leaf Phenolics Oleuropein, Hydroxytyrosol, Tyrosol, and Rutin Induce Apoptosis and Additionally Affect Temozolomide against Glioblastoma: In Particular, Oleuropein Inhibits Spheroid Growth by Attenuating Stem-like Cell Phenotype.

The effects of Olea europaea leaf extract (OLE) phenolics, including oleuropein (OL), hydroxytyrosol (HT), tyrosol (TYR), and rutin against glioblastoma (GB), independently and in combination with temozolomide (TMZ), were investigated in T98G and A172 cells. Cell growth was assessed by WST-1, real-time cell analysis, colony formation, and cell cycle distribution assays. A dual acridine orange propidium iodide (AO/PI) staining and annexin V assay determined cell viability. A sphere-forming assay, an intracellular oxidative stress assay, and the RNA expression of CD133 and OCT4 investigated the GB stem-like cell (GSC) phenotype. A scratch wound-healing assay evaluated migration capacity. OL was as effective as OLE in terms of apoptosis promotion (p < 0.001) and GSC inhibition (p < 0.001). HT inhibited cell viability, GSC phenotype, and migration rate (p < 0.001), but its anti-GB effect was less than the total effect of OLE alone. Rutin decreased reactive oxygen species production and inhibited colony formation and cell migration (p < 0.001). TYR demonstrated the least effect. The additive effects of OL, HT, TYR and rutin with TMZ were significant (p < 0.001). Our data suggest that OL may represent a novel therapeutic approach against GB cells, while HT and rutin show promise in increasing the efficacy of TMZ therapy.

Investigation of the Effectiveness of Oleuropein in a Three-Dimensional In Vitro Hepatocellular Tumor Sphere Model.

OBJECTIVES: This study was conducted to examine the dose-related effects over time of oleuropein on the proliferation and area of tumor spheroids in hepatocellular carcinoma cells. MATERIALS AND METHODS: We examined the possible effects of 100 to 500 µM dose concentrations of oleuropein on HepG2 cell proliferation using a real-time cell analyzer. A 3-dimensional hepatocellular carcinoma tumor spheroid model was established by seeding HepG2 cells at a density of 160 cells/well in custom 96-well microplates with low attachment surfaces and culturing for 3 days. Tumor spheres were treated with increasing oleuropein doses for 72 hours, and images were captured every 24 hours. The dose-dependent effects of oleuropein on tumor sphere size were analyzed by measuring the area of tumor spheres with ImageJ software. We conducted oleuropein viability and cytotoxicity analyses using calcein acetoxymethyl ester-based and propidium iodide-based staining in the tumor model. RESULTS: Oleuropein inhibited cell proliferation; as the dose concentration of oleuropein increased, so did its capacity to inhibit cell proliferation (P < .001). The size of untreated tumor spheres increased at 72 hours (P < .001). However, treatment with 100 to 500 µM oleuropein reduced tumor size by 63.56% to 88.06% compared with untreated cells at the end of 72 hours (P < .001). With increasing concentrations, oleuropein inhibited the viability of tumor spheres, eliminating necrotic death caused by tumor hypoxia. CONCLUSIONS: Overall, oleuropein reduced the size of tumors by inhibiting tumor proliferation and viability. In this context, oleuropein could be a candidate molecule for further extensive studies to reduce hepatocellular carcinoma tumors to meet Milan criteria for liver transplant.

Diabetes Mellitus-Mediated MALAT1 Expression Induces Glioblastoma Aggressiveness.

AIM: To describe the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in glioblastoma (GB) progression in patients concurrently diagnosed with diabetes mellitus (DM). MATERIAL AND METHODS: Formalin-fixed paraffin-embedded (FFPE) tumor samples of 47 patients diagnosed with GB only and 13 patients diagnosed with GB and DM (GB-DM) were enrolled in this study. Data for p53 and Ki67 immunohistochemical staining of the tumors and blood HbA1c levels of patients with DM were retrospectively collected. MALAT1 expression was assessed using quantitative real-time polymerase chain reaction. RESULTS: The coexistence of GB and DM induced the nuclear expression of p53 and Ki67 compared with GB only. MALAT1 expression was higher in GB-DM tumors than in GB only tumors. The expression of MALAT1 and HbA1c levels were positively correlated. Additionally, MALAT1 was positively correlated with tumoral p53 and Ki67. The disease-free survival of patients with GB-DM with high MALAT1 expression was shorter than that of those diagnosed with GB only and with a lower MALAT1 expression. CONCLUSION: Our findings suggest that one of the mechanisms of the facilitating effect of DM on GB tumor aggressiveness is via MALAT1 expression.

Co-loading of Temozolomide with Oleuropein or rutin into polylactic acid core-shell nanofiber webs inhibit glioblastoma cell by controlled release.

Glioblastoma (GB) has susceptibility to post-surgical recurrence. Therefore, local treatment methods are required against recurrent GB cells in the post-surgical area. In this study, we developed a nanofiber-based local therapy against GB cells using Oleuropein (OL), and rutin and their combinations with Temozolomide (TMZ). The polylactic acid (PLA) core-shell nanofiber webs were encapsulated with OL (PLAOL), rutin (PLArutin), and TMZ (PLATMZ) by an electrospinning process. A SEM visualized the morphology and the total immersion method determined the release characteristics of PLA webs. Real-time cell tracking analysis for cell growth, dual Acridine Orange/Propidium Iodide staining for cell viability, a scratch wound healing assay for migration capacity, and a sphere formation assay for tumor spheroid aggressiveness were used. All polymeric nanofiber webs had core-shell structures with an average diameter between 133 ± 30.7-139 ± 20.5 nm. All PLA webs promoted apoptotic cell death, suppressed cell migration, and spheres growth (p < 0.0001). PLAOL and PLATMZ suppressed GB cell viability with a controlled release that increased over 120 h, while PLArutin caused rapid cell inhibition (p < 0.0001). Collectively, our findings suggest that core-shell nano-webs could be a novel and effective therapeutic tool for the controlled release of OL and TMZ against recurrent GB cells.

Blood-Based Biomarkers in Afp Normal/Stable Hepatocellular Carcinoma: Diagnostic and Prognostic Relevance of Mir-10b for Patients on Liver Transplant List.

BACKGROUND: As a diagnostic criteria of hepatocellular carcinoma (HCC), the exact threshold of alpha-fetoprotein (AFP) is controversial. In additional, not all HCC tumors are AFP positive or secrete elevated amounts of AFP into the serum. However, the diagnosis of HCC is quite important on the liver transplant list. Therefore, the purpose of this study was to investigate the expression of circulating micro RNAs (miRNAs) in AFP-stable HCC patients. Thus, we aimed to determine a diagnostic biomarker in these patients. METHODS: Sixteen miRNAs were evaluated using a real-time quantitative reverse transcription polymerase chain reaction system in AFP-stable HCC and AFP-trending HCC patients. RESULTS: In our study, 46.7% (n = 28) of the patients diagnosed with HCC had stable/normal AFP levels. We detected that high expression of miR-24, miR-10b and the low expression of miR-143 were independently and significantly associated with HCC in AFP-stable compared with AFP trending (P < .05). Additionally, we demonstrated that the overexpression of miR-10b was associated with poor disease-free survival in HCC (P = 0.001). CONCLUSIONS: Although more clinical validations are needed for the diagnosis of HCC, our current results indicate that the coexistence of high expression of miR-10b and miR-24 may help clinicians adjust in the diagnosis of HCC in patients who are on the liver transplant list but awaiting biopsy for the diagnosis of HCC.