The stress-mediated antiproliferative effects of marine invertebrate extracts in human colon cancer cell models
- Autores: Verónica Ruiz Torres
- Directores de la Tesis: Vicente Micol Molina (dir. tes.), Enrique Barrajón Catalán (codir. tes.)
- Lectura: En la Universidad Miguel Hernández de Elche ( España ) en 2019
- Idioma: español
- Tribunal Calificador de la Tesis: María del Val Bermejo Sanz (presid.), Miguel Saceda Sánchez (secret.), Virginia García Cañas (voc.), Melissa Janae LaBonte Wilson (voc.), Javier Abel Menéndez Menéndez (voc.)
- Programa de doctorado: Programa de Doctorado en Biología Molecular y Celular por la Universidad Miguel Hernández de Elche
- Materias:
- Enlaces
- Tesis en acceso abierto en: RediUMH (pdf)
- Resumen
Cancer is one of the leading causes of death worldwide and requires the attention and effort of the scientific community for the development of new strategies and the discovery of drugs that help fight the disease [1]. It is necessary to discover novel effective therapies focused on avoiding cancer cell proliferation and reducing side effects.
Marine compounds, produced to survive in response to harsh and competitive environmental conditions, are postulated as a potential anticancer source. In the last decades, marine metabolites have shown novel wide chemical structures, which have been attributed to interesting biological activities and this fact has been registered by the increasing numbers of drugs approved by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). In particular, marine invertebrates are considered one of the richest biodiverse groups. To date, a large number of natural products extracted or synthesized based on marine compounds from invertebrates have been established as antineoplastic drugs.
In chapter 1, the current marine natural products (MNPs) that have been established as antineoplastic drugs were reviewed and their putative mechanisms of action in the different hallmarks of cancer described, giving an overview of the richness of the chemical structures that they offer and introducing the use of virtual screening for drug discovery.
This thesis, in chapter 2, focuses on the search of the antiproliferative effect of several invertebrate marine extracts in human colon cancer cell models. The first part of the project focuses on the search for marine organisms that have intra and interspecific competence through the production of bioactive compounds. A selection of 20 organisms was made based on bibliographic sources and relayed on observations of competence in experimental aquariums. The next part consisted in to screen the in vitro antiproliferative effect on a panel of colon cancer cell models. Four extracts were selected due to their potential cytotoxic effect: Phyllidia varicosa (NA extract) and Dolabella auricularia (NB extract), obtained from two nudibranchs, Carotalcyon sp (CR extract) obtained from a soft coral and Pseudocolochirus violaceus (PS extract) from a holothurian. The main bioactive compounds (98 compounds) represented in these four extracts were identified using an HPLC-ESI-TOF-MS analysis. Among the most abundant compounds characterized in each extract, terpenes and diterpenes, and steroids (CR); cembranolides (PS); diterpenes, polyketides and indole terpenes (NA); and porphyrin, drimenyl cyclohexanone and polar steroids (NB), were proposed to be the candidates for the observed activity.
CR, PS, NA, and NB showed strong antiproliferative ability and a cytostatic effect arresting the cell cycle in the G2/M phase. Likewise, CR, NA and NB extracts induced early apoptosis and PS extract exerted necrotic cell death. The four extracts showed a remarkable effect consisting on a dramatic intracellular reactive oxygen species (ROS) accumulation and mitochondrial depolarization, caspase activation and DNA damage.
In Chapter 3, the effect of marine natural products as inhibitors of rapamycin target (mTOR) in mammals was studied. This kinase is a master regulator of cell growth and metabolism and is deregulated in many types of cancer. Our results showed evidence of 11 pure compounds (selected by molecular coupling and calculated ADMET parameters) and two marine extracts to inhibit mTOR with the same effectiveness.
Finally, in Chapter 4, we explored in depth the antiproliferative effect of NB extract mediated by an induction of oxidative and endoplasmic reticulum stress in the human colon cancer cell model HCT-116. First, we found an overexpression of endoplasmic reticulum (ER) stress markers and an overproduction of reactive oxygen species (ROS) basally in the colon cancer cell model compared to the normal colon cells. This difference in the basal stress level made the tumor cells more sensitive to the NB extract. The results suggest that NB extract significantly increases cellular stress by inducing ROS and overexpressing proteins related to ER stress through the response to unfolding proteins.
In addition to the antiproliferative capacity, the ability of NB to inhibit one of the most dangerous characteristics of tumor cells, the migration and invasion qualities of superinvasive models from HCT-116 was studied. The results were promising in showing that NB significantly reduced the migration and invasion rate of the most superinvasive populations with a smaller effect on the non-tumor line.
This thesis, therefore, demonstrates that marine compounds are a potential source of anti-cancer drugs due to the chemical diversity and broad biological activity that they offer. This fact is reflected in the increase in the number of drugs of marine origin that have been approved to date and the large number of scientific studies related to the field that are underway. In addition, this thesis offers interesting results about potential antitumor activity from marine invertebrate extracts and reveals some strengths of its mechanism of action. Likewise, the present study offers results of how the new strategies of computational screening that allow the search of regulatory compounds of key targets against cancer increase the effectiveness in the search of antitumor compounds.
