Teodoro Vargas

Antitumor effect of 5-fluorouracil is enhanced by rosemary extract in both drug sensitive and resistant colon cancer cells.

5-Fluorouracil (5-FU) is the most used chemotherapeutic agent in colorectal cancer. However, resistance to this drug is relatively frequent, and new strategies to overcome it are urgently needed. The aim of this work was to determine the antitumor properties of a supercritical fluid rosemary extract (SFRE), alone and in combination with 5-FU, as a potential adjuvant therapy useful for colon cancer patients. This extract has been recognized as a healthy component by the European Food Safety Authority (EFSA). The effects of SFRE both alone and in combination with 5-FU were evaluated in different human colon cancer cells in terms of cell viability, cytotoxicity, and cell transformation. Additionally, colon cancer cells resistant to 5-FU were used to assay the effects of SFRE on drug resistance. Finally, qRT-PCR was performed to ascertain the mechanism by which SFRE potentiates the effect of 5-FU. Our results show that SFRE displays dose-dependent antitumor activities and exerts a synergistic effect in combination with 5-FU on colon cancer cells. Furthermore, SFRE sensitizes 5-FU-resistant cells to the therapeutic activity of this drug, constituting a beneficial agent against both 5-FU sensitive and resistant tumor cells. Gene expression analysis indicates that the enhancement of the effect of 5-FU by SFRE might be explained by the downregulation of TYMS and TK1, enzymes related to 5-FU resistance.

A link between lipid metabolism and epithelial-mesenchymal transition provides a target for colon cancer therapy.

The alterations in carbohydrate metabolism that fuel tumor growth have been extensively studied. However, other metabolic pathways involved in malignant progression, demand further understanding. Here we describe a metabolic acyl-CoA synthetase/stearoyl-CoA desaturase ACSL/SCD network causing an epithelial-mesenchymal transition (EMT) program that promotes migration and invasion of colon cancer cells. The mesenchymal phenotype produced upon overexpression of these enzymes is reverted through reactivation of AMPK signaling. Furthermore, this network expression correlates with poorer clinical outcome of stage-II colon cancer patients. Finally, combined treatment with chemical inhibitors of ACSL/SCD selectively decreases cancer cell viability without reducing normal cells viability. Thus, ACSL/SCD network stimulates colon cancer progression through conferring increased energetic capacity and invasive and migratory properties to cancer cells, and might represent a new therapeutic opportunity for colon cancer treatment.

The Ellagic Acid Derivative 4,4′-Di-O-Methylellagic Acid Efficiently Inhibits Colon Cancer Cell Growth through a Mechanism Involving WNT16

Ellagic acid (EA) and some derivatives have been reported to inhibit cancer cell proliferation, induce cell cycle arrest, and modulate some important cellular processes related to cancer. This study aimed to identify possible structure-activity relationships of EA and some in vivo derivatives in their antiproliferative effect on both human colon cancer and normal cells, and to compare this activity with that of other polyphenols. Our results showed that 4,4′-di-O-methylellagic acid (4,4′-DiOMEA) was the most effective compound in the inhibition of colon cancer cell proliferation. 4,4′-DiOMEA was 13-fold more effective than other compounds of the same family. In addition, 4,4′-DiOMEA was very active against colon cancer cells resistant to the chemotherapeutic agent 5-fluoracil, whereas no effect was observed in nonmalignant colon cells. Moreover, no correlation between antiproliferative and antioxidant activities was found, further supporting that structure differences might result in dissimilar molecular targets involved in their differential effects. Finally, microarray analysis revealed that 4,4′-DiOMEA modulated Wnt signaling, which might be involved in the potential antitumor action of this compound. Our results suggest that structural-activity differences between EA and 4,4′-DiOMEA might constitute the basis for a new strategy in anticancer drug discovery based on these chemical modifications.

Genes associated with metabolic syndrome predict disease-free survival in stage II colorectal cancer patients. A novel link between metabolic dysregulation and colorectal cancer

Studies have recently suggested that metabolic syndrome and its components increase the risk of colorectal cancer. Both diseases are increasing in most countries, and the genetic association between them has not been fully elucidated. The objective of this study was to assess the association between genetic risk factors of metabolic syndrome or related conditions (obesity, hyperlipidaemia, diabetes mellitus type 2) and clinical outcome in stage II colorectal cancer patients. Expression levels of several genes related to metabolic syndrome and associated alterations were analysed by real‐time qPCR in two equivalent but independent sets of stage II colorectal cancer patients. Using logistic regression models and cross‐validation analysis with all tumour samples, we developed a metabolic syndrome‐related gene expression profile to predict clinical outcome in stage II colorectal cancer patients. The results showed that a gene expression profile constituted by genes previously related to metabolic syndrome was significantly associated with clinical outcome of stage II colorectal cancer patients. This metabolic profile was able to identify patients with a low risk and high risk of relapse. Its predictive value was validated using an independent set of stage II colorectal cancer patients. The identification of a set of genes related to metabolic syndrome that predict survival in intermediate‐stage colorectal cancer patients allows delineation of a high‐risk group that may benefit from adjuvant therapy and avoid the toxic and unnecessary chemotherapy in patients classified as low risk. Our results also confirm the linkage between metabolic disorder and colorectal cancer and suggest the potential for cancer prevention and/or treatment by targeting these genes.

Modulation of estrogen and epidermal growth factor receptors by rosemary extract in breast cancer cells.

Breast cancer is the leading cause of cancer‐related mortality among females worldwide, and therefore the development of new therapeutic approaches is still needed. Rosemary (Rosmarinus officinalis L.) extract possesses antitumor properties against tumor cells from several organs, including breast. However, in order to apply it as a complementary therapeutic agent in breast cancer, more information is needed regarding the sensitivity of the different breast tumor subtypes and its effect in combination with the currently used chemotherapy. Here, we analyzed the antitumor activities of a supercritical fluid rosemary extract (SFRE) in different breast cancer cells, and used a genomic approach to explore its effect on the modulation of ER‐α and HER2 signaling pathways, the most important mitogen pathways related to breast cancer progression. We found that SFRE exerts antitumor activity against breast cancer cells from different tumor subtypes and the downregulation of ER‐α and HER2 receptors by SFRE might be involved in its antitumor effect against estrogen‐dependent (ER+) and HER2 overexpressing (HER2+) breast cancer subtypes. Moreover, SFRE significantly enhanced the effect of breast cancer chemotherapy (tamoxifen, trastuzumab, and paclitaxel). Overall, our results support the potential utility of SFRE as a complementary approach in breast cancer therapy.

Nutritional genomics for the characterization of the effect of bioactive molecules in lipid metabolism and related pathways

Cardiovascular disease and cancer are the main causes of morbidity and mortality worldwide. Thus, investigators have focused their efforts on gaining insight into understanding the mechanisms involved in the development and evolution of these diseases. In the past decade, and with the contribution of the ‐omics technologies, strong evidence has supported an essential role of gene–nutrient interactions in these processes, pointing at natural bioactive molecules as promising complementary agents that are useful in preventing or mitigating these diseases. In addition, alterations in lipid metabolism have recently gained strong interest since they have been described as a common event required for the progression of both diseases. In the present review, we give an overview of lipid metabolism, mainly focusing on lipoprotein metabolism and the mechanisms controlling lipid homeostasis. In addition, we review the modulation of lipid metabolism by bioactive molecules, highlighting their potential use as therapeutic agents in preventing, and treating chronic diseases such as cardiovascular disease and cancer. Finally, we report the usefulness of the ‐omics technologies in nutritional research, focusing on recent findings, within nutritional genomics, in the interaction of bioactive components from foods with several genes that are involved in the development and progression of these diseases.

Clinical relevance of the differential expression of the glycosyltransferase gene GCNT3 in colon cancer

Altered glycosylation is considered a universal cancer hallmark. Mucin-type core 2 1,6-N-acetylglucosaminyltransferase enzyme (C2GnT-M), encoded by the GCNT3 gene, has been reported to be altered in tumours and to possess tumour suppressor properties. In this work, we aimed to determine the possible role of GCNT3 gene expression as prognostic marker in colon cancer. We investigated the differential expression of GCNT3 gene among tumour samples from stage II colon cancer patients by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Univariate and Multivariate Cox regression analyses were used to determine the correlation between GCNT3 expression and disease-free survival. The risk of relapse in GCNT3 low-expressing cancer patients was significantly higher than that in GCNT3 high-expressing patients in both training (Hazard Ratio (HR) 4.26, p=0.002) and validation (HR 3.06, p=0.024) series of patients, and this association was independent of clinical factors. Additionally, qRT-PCR was used to explore the modulation of GCNT3 expression by different antitumour drugs. Three chemotherapeutic agents with different mechanism of action (5-fluorouracil, bortezomib and paclitaxel) significantly induced GCNT3 expression in several cancer cells, being observed the correlation between antitumour action and GCNT3 modulation, whereas this gene was not modulated in cells that do not respond to treatment. Overall, these results indicate that low GCNT3 expression is a promising prognostic biomarker for colon cancer that could be used to identify early-stage colon cancer patients at high risk of relapse. Additionally, our results suggest that this enzyme might also constitute a biomarker to monitor tumour response to chemotherapy in cancer patients.

Antiproliferative effect of alkylglycerols as vehicles of butyric acid on colon cancer cells.

The anticarcinogenic activity of synthetic 1-O-octadecyl-2,3-dibutyroilglycerol (D-SCAKG) in tumor-cell line of colonocytes (SW620) was performed. The effect of the previously digested D-SCAKG under in vitro intestinal conditions was compared to the bioactivity of non-digested D-SCAKG. Antiproliferative activity of each individual product from digestion (1-O-octadecyl-2-butyroilglycerol; 1-O-octadecyl glycerol; butyric acid) was also performed. The impact of solubilization of lipid products within micellar structures was also tested. The 1-O-octadecyl glycerol was the most active compound, followed by 1-O-octadecyl-2-butyroilglycerol, D-SCAKG and butyric acid. The 1-O-octadecyl glycerol and butyric acid were the only molecules that showed antiproliferative effect in absence of micelles. Digested D-SCAKG was 4-fold more effective than non-digested D-SCAKG. A synergism between 1-O-octadecyl-2-butyroilglycerol and 1-O-octadecyl glycerol was evidenced. As summary, the synthetic D-SCAKG seems to be an interesting antitumoral lipid against colonocytes, especially after previous intestinal digestion, and mainly due to the synergism of the major products, namely 1-O-octadecyl-2-butyroilglycerol and 1-O-octadecyl glycerol. At the same time, 1-O-octadecyl-2-butyroilglycerol would constitute a stable esterified form of butyric acid for its vehiculization.

Targeting the lipid metabolic axis ACSL/SCD in colorectal cancer progression by therapeutic miRNAs: miR-19b-1 role

An abnormal acyl-CoA synthetase/stearoyl-CoA desaturase (ACSL/SCD) lipid network fuels colon cancer progression, endowing cells with invasive and migratory properties. Therapies against this metabolic network may be useful to improve clinical outcomes. Because micro-RNAs (miRNAs/miRs) are important epigenetic regulators, we investigated novel miRNAs targeting this pro-tumorigenic axis; hence to be used as therapeutic or prognostic miRNAs. Thirty-one putative common miRNAs were predicted to simultaneously target the three enzymes comprising the ACSL/SCD network. Target validation by quantitative RT-PCR, Western blotting, and luciferase assays showed miR-544a, miR-142, and miR-19b-1 as major regulators of the metabolic axis, ACSL/SCD. Importantly, lower miR-19b-1 expression was associated with a decreased survival rate in colorectal cancer (CRC) patients, accordingly with ACSL/SCD involvement in patient relapse. Finally, miR-19b-1 regulated the pro-tumorigenic axis, ACSL/SCD, being able to inhibit invasion in colon cancer cells. Because its expression correlated with an increased survival rate in CRC patients, we propose miR-19b-1 as a potential noninvasive biomarker of disease-free survival and a promising therapeutic miRNA in CRC.

NOVEL POLYPHENOLS THAT INHIBIT COLON CANCER CELL GROWTH AFFECTING CANCER CELL METABOLISM

New series of polyphenols with a hydrophilic galloyl-based head and a hydrophobic N-acyl tail, linked through a serinol moiety, have been synthesized and tested against colon cancer cell growth. Our structure activity relationship studies revealed that galloyl moieties are essential for growth inhibition. Moreover, the length of the N-acyl chain is crucial for the activity. Introduction of a (Z) double bond in the acyl chain increased the anticancer properties. Our findings demonstrate that 16, the most potent compound within this series, has inhibitory effects on colon cancer cell growth and metabolism (glycolysis and mitochondrial respiration) at the same time that it activates 5′AMP-activated kinase (AMPK) and induces apoptotic cell death. Based on these results, we propose that 16 might reprogram colon cancer cell metabolism through AMPK activation. This might lead to alterations on cancer cell bioenergy compromising cancer cell viability. Importantly, these antiproliferative and proapoptotic effects are selective for cancer cells. Accordingly, these results indicate that 16, with an unsaturated C18 chain, might be a useful prototype for the development of novel colon cancer cell growth inhibitors affecting cell metabolism.