A Synergistic Approach Therapy for Colorectal Cancer Based on Exosomes and Exploitation of Metabolic Pathways.

In order to reduce the side effects of traditional chemotherapy in the treatment of colorectal cancer (CRC), a new drug delivery system has been developed in this work, based on exosomes that can host two drugs that act synergistically: farnesol (that stops the cell cycle) and paclitaxel (prevents microtubule system depolymerization). Firstly, exosomes were isolated from different cell cultures (from colorectal cancer and from fibroblast as example of normal cell line) by different methods and characterized by western blot, TEM and DLS, and results showed that they express classical protein markers such as CD9 and HSP-70 and they showed spherical morphology with sizes from 93 nm to 129 nm depending on the source. These exosomes were loaded with both drugs and its effect was studied in vitro. The efficacy was studied by comparing the viability of cell cultures with a colorectal cancer cell line (HCT-116) and a normal cell line (fibroblast HS-5). Results showed that exosomes present a specific effect with more reduction in cell viability in tumour cultures than healthy ones. In summary, exosomes are presented in this work as a promising strategy for colorectal cancer treatment.

Development of a thermosensitive hydrogel based on Polaxamer 407 and gellan gum with inclusion complexes (Sulfobutylated-ß-cyclodextrin-Farnesol) as a local drug delivery system.

This work proposes the development of a thermosensitive local drug release system based on Polaxamer 407, also known as Pluronic® F-127 (PF-127), Gellan Gum (GG) and the inclusion complex Sulfobutylated-ß-cyclodextrin (CD) with Farnesol (FOH). Rheological properties of the hydrogels and their degradation were studied. According to the rheological results, a solution of 20% w/v of PF-127 forms a strong gel with a gelling temperature of about 25 °C (storage modulus of 15,000 Pa). The addition of the GG increased the storage modulus (optimal concentration of 0.5 % w/v) twofold without modifying the gelling temperature. Moreover, including 0.5% w/v of GG also increased 6 times the degradation time of the hydrogel. Regarding the inclusion complex, the addition of free CD decreased the viscosity and the gel strength since polymer chains were included in CD cavity without affecting the gelling temperature. Contrarily, the inclusion complex CD-FOH did not significantly modify any property of the formulation because the FOH was hosted in the CD. Furthermore, a mathematical model was developed to adjust the degradation time. This model highlights that the addition of the GG decreases the number of released chains from the polymeric network (which coincides with an increase in the storage modulus) and that the free CD reduces the degradation rate, protecting the polymeric chains. Finally, FOH release was quantified with a specific device, that was designed and printed for this type of system, observing a sustainable drug release (similar to FOH aqueous solubility, 8 µM) dependent on polymer degradation.

An Approach to Minimize Tumour Proliferation by Reducing the Formation of Components for Cell Membrane.

Isoprenoids are natural compounds essential for a great number of cellular functions. One of them is farnesol (FOH), which can reduce cell proliferation, but its low solubility in aqueous solvents limits its possible clinical use as a pharmacological tool. One alternative is the use of cyclodextrins (CDs) which house hydrophobic molecules forming inclusion complexes. To assess FOH potential application in anticancer treatments, Sulfobutylated ß-cyclodextrin Sodium Salt (SBE-ß-CD) was selected, due to it has high solubility, approbation by the FDA, and numerous studies that ensure its safety to be administered parenterally or orally without nephrotoxicity associated. The therapeutic action of farnesol and complex were studied in different carcinoma cells, compared with a normal cell line. Farnesol showed selectivity, affecting the viability of colon and liver cancer cells more than in breast cancer cells and fibroblasts. All cells suffered apoptosis after being treated with 150 µM of free FOH, but the complex reduced their cell viability between 50 and 75%. Similar results were obtained for both types of isomers, and the addition of phosphatidylcholine reverses this effect. Finally, cell cycle analysis corroborates the action of FOH as inducer of a G0/G1 phase; when the cells were treated using the complex form, this viability was reduced, reaching 50% in the case of colon and liver, 60% in fibroblasts, and only 75% in breast cancer.