Bozkurt, E. | bioRxiv Science

bioRxiv2020

TRAIL signalling promotes entosis in colorectal cancer

Entosis is a form of non-phagocytic cell-in-cell (CIC) interaction where a living cell enters into another. Tumours show evidence of entosis, however factors controlling entosis remain to be elucidated. Here we find that the death receptor ligand TRAIL is a potent activator of entosis in colon cancer cells. CLEM/3D confocal microscopy analysis revealed ultrastructural features of entosis and subsequent entotic cell death of inner cells upon TRAIL treatment. Induction of entosis and apoptosis by TRAIL were mutually exclusive events but both required the presence of caspase-8. Bax/Bak double knock-out or caspase inhibition altered the fate of inner cells from entotic cell death to survival and escape. Analysis of colorectal cancer tumours showed a significant association between expression levels of TRAIL and CICs. Notably, the presence of CICs in the invasive front regions of colorectal tumours was significantly correlated with adverse patient prognosis.

cancer biology↗

bioRxiv2020

Development of EphA2 siRNA-loaded lipid nanoparticles and combination with a small-molecule histone demethylase inhibitor in prostate cancer cells and tumor spheroids

siRNAs hold a great potential for cancer therapy, however, poor stability in body fluids and low cellular uptake limit their use in the clinic. To enhance the bioavailability of siRNAs in tumors, novel, safe, and effective carriers are needed. Here, we developed cationic solid lipid nanoparticles (cSLNs) to carry siRNAs targeting EphA2 receptor tyrosine kinase (siEphA2), which is overexpressed in many solid tumors including prostate cancer (PCa). Using DDAB cationic lipid instead of DOTMA reduced nanoparticle size and enhanced both cellular uptake and gene silencing in PCa cells. After verifying the efficacy of siEphA2-loaded nanoparticles, we further evaluated a potential combination with a histone lysine demethylase inhibitor, JIB-04. Silencing EphA2 by siEphA2-loaded DDAB-cSLN did not affect the viability (2D and 3D), migration, and clonogenicity of PC-3 cells alone. However, upon co-administration, there was a decrease in the aforementioned cellular responses due to JIB-04. Furthermore, JIB-04 decreased EphA2 expression, and thus, silencing efficiency of siEphA2-loaded nanoparticles was further increased with co-treatment. In conclusion, we have successfully developed a novel siRNA-loaded lipid nanoparticle for targeting EphA2. Moreover, detailed preliminary results of the effects of JIB-04, alone and in combination with siEphA2, on PCa cells and tumor spheroids were presented for the first time. Our delivery system provides high transfection efficiency and shows a great promise for targeting other genes and cancer types in further in vitro and in vivo studies.

pharmacology and toxicology↗