Experimental Hepatic Metastasis Treatment with Antiangiogenic microRNA-Encapsulated Nanoparticles

Colorectal cancer is one of the leading causes of cancer death worldwide as a result of its considerable risk of development of metastases. When metastasic disease is confined to the liver, partial liver resection is the only curative therapeutic option. For this reason, it is important to study new antimetastasic treatments. Cancer metastasic cells have many strategies to survive, colonize and growth in the hepatic microenvironment. One of the most important strategies is known as angiogenesis. During angiogenesis, tumor cells recruit the endothelial cells and create new blood vessels to support the tumor growth. In this work, we studied the transformation of liver sinusoidal endothelial cells (LSEC) during metastasic process and their post-transcriptional regulation by microRNAs (miRNA). In addition, we designed a strategy to block LSEC transformation and therefore angiogenesis and metastasis progression. To perform this assay, CT26 cells were intrasplenically inoculated to mice and after two weeks, once the cells metastasized the liver, tumor microenvironment LSECs were isolated by liver perfusion and gradient separation. Then, a microarray was carried out to compare gene and miRNA expression pattern of healthy LSECs with respect to LSECs that received the metastasic tumor. Bioinformatic tools selected E2F1 and VEGF genes as proteins involved in tumor progression and miRNA-20 and miRNA-652 were respectively found as regulators of the mentioned genes expression. Both genes and microRNAs were in vitro validated by qPCR and western blot. Finally, chondroitin sulphate-conjugated sorbitan ester based nanoparticles loaded with selected miRNAs were designed to guide them directly to LSECs and repress the angiogenesis and tumor progression in vitro and in vivo.