ABSTRACT
PURPOSE: Anaplastic thyroid carcinoma (ATC) is an aggressive, chemo-resistant malignancy. Chemo-resistance is often associated with changes in activity of the RAS/MAPK/ERK and PI3K/AKT/mTOR pathways and/or a high expression of ATP binding cassette (ABC) transporters, such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). To assess the therapeutic efficacy in ATC of a combination of the dual mTOR kinase inhibitor vistusertib (AZD2014) and paclitaxel (PTX), we generated a new cell line (Rho-) via the selection of human thyroid carcinoma 8505C cells that exhibit a low accumulation of rhodamine 123, which serves as a P-gp and BCRP substrate. METHODS: Immunohistochemistry was used for P-gp and BCRP expression analyses in primary ATC patient samples. Spheroid formation and immunodeficient NSG mice were used for performing in vitro and in vivo tumorigenicity assays, respectively. MTT, flow-cytometry, fluorescent microscopy, cell death and proliferation assays, as well as migration, invasion and gelatin degradation assays, were used to assess the potential of AZD2014 to enhance the effects of PTX. ATC xenografts in SCID mice were used for evaluating in vivo treatment efficacies. RESULTS: Rho- cells were found to be 10-fold more resistant to PTX than 8505C cells and, in addition, to be more tumorigenic. We also found that AZD2014 sensitized Rho- cells to PTX by inhibiting proliferation and by inducing autophagy. The combined use of AZD2014 and PTX efficiently inhibited in vitro ATC cell migration and invasion. Subsequent in vivo xenograft studies indicated that the AZD2014 and PTX combination effectively suppressed ATC tumor growth. CONCLUSIONS: Our data support results from recent phase I clinical trials using combinations of AZD2014 and PTX for the treatment of solid tumors. Such combinations may also be employed for the design of novel targeted ATC treatment strategies.
Subject(s)
Morpholines/therapeutic use , Paclitaxel/therapeutic use , Protein Kinase Inhibitors/therapeutic use , Thyroid Carcinoma, Anaplastic/drug therapy , Aged , Aged, 80 and over , Animals , Apoptosis/drug effects , Benzamides , Cell Death/drug effects , Cell Line, Tumor , Cell Movement/drug effects , Drug Resistance, Neoplasm , Female , Flow Cytometry , Humans , Immunohistochemistry , Male , Mice , Mice, SCID , Middle Aged , Pyrimidines , Xenograft Model Antitumor AssaysABSTRACT
BACKGROUND: Implant-related infections represent one of the most severe complications in orthopaedics. A fast-resorbable, antibacterial-loaded hydrogel may reduce or prevent bacterial colonization and biofilm formation of implanted biomaterials. QUESTIONS/PURPOSES: We asked: (1) Is a fast-resorbable hydrogel able to deliver antibacterial compounds in vitro? (2) Can a hydrogel (alone or antibacterial-loaded) coating on implants reduce bacterial colonization? And (3) is intraoperative coating feasible and resistant to press-fit implant insertion? METHODS: We tested the ability of Disposable Antibacterial Coating (DAC) hydrogel (Novagenit Srl, Mezzolombardo, Italy) to deliver antibacterial agents using spectrophotometry and a microbiologic assay. Antibacterial and antibiofilm activity were determined by broth microdilution and a crystal violet assay, respectively. Coating resistance to press-fit insertion was tested in rabbit tibias and human femurs. RESULTS: Complete release of all tested antibacterial compounds was observed in less than 96 hours. Bactericidal and antibiofilm effect of DAC hydrogel in combination with various antibacterials was shown in vitro. Approximately 80% of the hydrogel coating was retrieved on the implant after press-fit insertion. CONCLUSIONS: Implant coating with an antibacterial-loaded hydrogel reduces bacterial colonization and biofilm formation in vitro. CLINICAL RELEVANCE: A fast-resorbable, antibacterial-loaded hydrogel coating may help prevent implant-related infections in orthopaedics. However, further validation in animal models and properly controlled human studies is required.
