The Molecular Mechanism Study Of E3 Ubiquitin Ligase RNF135 Regulating The Tumorigenesis Of Tongue Cancer And Construction Of Therapeutic Nano-controlled Release System

The global burden caused by cancer is growing at an alarming pace and emphasizes the need for urgent implementation of effectual prevention strategies. Oral cancer is one of the most burning types. It ranks among the 10 most common types of cancer around the world. The 5-year relative survival rate of oral cancer patients is improving due to the improvement of treatment, but it is far from satisfaction. Tongue cancer is the most common type of the oral cancer. Male is more vulnerable than female. The exact pathogenesis of it has not yet been fully understood. Environment factors, genetics, and immune status were believed to be related to the tumorigenesis of the tongue cancer.Ubiquitin is a highly conserved small molecule protein expressed in eukaryotic cells. It is composed of 76 amino acids. With the help of related enzymes, ubiquitin can bind and ubiquitinate the target protein, which modulates the activity or mediates the degradation of target proteins. The catalytic process which guides ubiquitin binding to the target protein takes three steps. Three kinds of enzymes, E1, E2, and E3 ubiquitin ligase, are requisite in this process. There are two E1 ubiquitin ligases, UbEl and UBE1L2; 40 E2 ubiquitin ligases and more than 600 E3 ubiquitin ligases in mammalian cells. The dysregulation of E3 ubiquitin ligases as well as their ubiquitin substrates are often associated with human diseases, including cancer. E3 ubiquitin ligases are considered as the second most widespread cancer related functional family. The cancer-associated proteins, including tumor suppressors, can be degraded by the ubiquitination system. Several cancers, like prostate cancer, breast cancer, colon cancer, ovarian cancer, and leukemia, have been confirmed to be related to the abnormal of E3 ubiquitin ligases. In order to find the tongue cancer-related E3 ubiquitin ligase, we performed a screening assay of an E3 ubiquitin ligase library and validated the role of candidate protein in the tongue cancer cell lines.Nanoparticles and nanofibers as carriers are chosen to delivery doxorubicin hydrochloride, one of widely applicable anti-cancer drugs. Meanwhile the effect of nanoparticles and nanofibers on killing cancer cells were also investigated. Nanoparticles as ideal drug carriers are often used to facilitate improvements in the therapeutic index of drugs. In this study, natural polymers carboxymethyl chitosan and lysozyme were mixed to prepare carboxymethyl chitosan-lysozyme nanoparticles by electrostatic self-assembly interactions. In addition, layered silicate rectorite was introduced into nanoparticles to explore the effect on the efficacy and controlled release of doxorubicin hydrochloride. It was confirmed that the average size of nanoparticles increased with the addition of rectorite, and the interlayer distance of rectorite in nanoparticles was enlarged by the intercalation of polymer chains. Besides, it also normalized the encapsulation efficiency and loading capacity of doxorubicin hydrochloride in nanoparticles increased markedly with the accretion of rectorite. The incorporation of rectorite into nanoparticles could reduce the initial burst release and prolong the therapeutic time. Such results suggest that the rectorite-intercalated nanoparticles are promising anticancer drug carriers for efficient cancer therapy.Coaxial electrospinning technique can use to protect drugs that are enclosed within the polymer sheath from being influenced by the environment hazards. The electrospun core-sheath structured nanofibers can reduce the toxic and side effects of drugs, improve the effectiveness of drug therapies. In the study doxorubicin hydrochloride-loaded core-sheath nanofibers were prepared by coaxial electrospinning. The prepared core-sheath nanofibers had small and uniform diameters. Rectorite was introduced in polyethylene oxide solution to explore the effect on the ability of sustained release. The results of live/dead assay suggested that doxorubicin hydrochloride-polyethylene oxide/rectorite core-sheath nanofibers still had strong anticancer activity against HepG2 cells after 48 hours of in vitro culture. The data of cell migration assay implied that the addition of rectorite into core-sheath nanofibers could prolong the therapeutic time of anti-cancer cells.