?(Fig.4d,4d, k). NP-associated drugs THZ1 for 12?days. At the endpoint of this experiment, cells in SeedEZTM scaffold supplied with complete medium were stained with Texas Red?-X phalloidin (Invitrogen), followed by fluorescence imaging (Zeiss). Cell viability in 3D cultures was quantified by an alamarBlue assay (Bio-Rad). Generation of Sar-R HN8 cells Briefly, HN8 cells were treated with IC90 dose of saracatinib (20?M) and maintained in the medium containing IC50 dose of 2?M for 5 generations. The dose was gradually increased by 1?M every 2 or 3 3?weeks until the maximum tolerated dose of 5?M was reached. Solid-Phase Peptide Synthesis Synthesis of the peptide was carried out using the Fmoc strategy manually in a glass reaction vessel fitted with a sintered glass frit using 2-chlorotritylchloride. Coupling reactions were performed manually by using 2 equiv of N-Fmoc-protected amino acid (relative to the resin loading) activated in situ with 2 equiv of PyBOP and 4 equiv of diisopropylethylamine (DIPEA) in DMF (10?mL/g resin). The coupling efficiency was assessed by the Kaiser test. N-Fmoc protecting groups were removed by treatment with a piperidine/DMF answer (1:4) for 10?min (10?mL/g resin). The process was repeated three times and the completeness of deprotection verified by UV absorption of the piperidine washings at 301?nm. Synthetic linear peptides were recovered directly upon acid cleavage. Before cleavage, the resin was washed thoroughly with methylene chloride. The linear peptides were then released from the resin by treatments with a solution of acetic acid/trifluoroethanol/methylene chloride (1:1:8, 10?mL/mg resin, 2 30?min). Hexane (5-10 volumes) was added to the collected filtrates, and the crude peptides were isolated after concentration as white solids. The residue was dissolved in the minimum of methylene chloride and diethyl ether was added to precipitate peptides, followed by triturated and washed three times with diethyl ether to obtain crude materials. Peptide was further purified by preparative HPLC prior to conjugation. Development and characterization of the saracatinib/capivasertib co-delivery NPs Linear-dendritic mPEG5000-BMA4 made up of four branches of amine groups, the cathepsin B (CTSB)-sensitive polymeric drug EMCN carrier, was synthesized as described previously [5]. To prepare single drug-loaded NPs, hydrophobic drugs (saracatinib or capivasertib) were loaded into NPs by the solvent evaporation method. Briefly, drug (1.0?mg) and amphiphilic polymer (10?mg) were first dissolved in anhydrous chloroform/methanol (1/1) in a 10?mL round bottom flask. The solvent mixture was evaporated under vacuum to form a thin film. PBS buffer (1?mL) was added to re-hydrate the thin film, followed by 30?min of sonication. Free drugs not associated with THZ1 the NPs were removed by running the NP solutions through centrifugal filter devices (MWCO: 3.5?kDa, Microcon?). The drug-loaded formulation around the filters were recovered with PBS. To prepare co-delivery NPs (NP-com), saracatinib and capivasertib (1.95?mg, mole ratio = 1:1) were initially dissolved in methanol followed by adding amphiphilic polymer (20?mg in equivalent volume of chloroform). The mixture was transferred into a 10?mL round bottom flask, and the remaining procedure was performed similarly as preparation of single drug-loaded NPs. The amount of drugs loaded in the NPs was analyzed by HPLC (Agilent 1200 LC, Santa Clara, CA). The drug loading was calculated according to the calibration curve between the HPLC area values and concentrations of drug standard. The loading efficiency was defined as the ratio of drug loaded into NPs to the initial drug content. The size and size distribution of the drug-loaded NPs were measured by dynamic light scattering (DLS) instrument three times with an acquisition time of 30?s at room heat. In vitro drug release testing The drug released from the single drug-loaded NPs or co-NPs was carried out in the solution with or without CTSB. Cysteine answer in Mcllvaines buffer (10?mm) was added in equal volume of enzyme stock answer and pre-incubated for 5?min at 37?C. The NPs were incubated in the buffer at 37?C for 48?h in the presence or absence of CTSB (100?nM, pH = 5.4). A drug release control study at physiological condition (without enzyme, pH?7.4) was also performed. At predetermined time points, the THZ1 samples were withdrawn and analyzed by RP-HPLC (Agilent 1200 LC, Zorbax C18 column 4.6 150?mm) with gradient elution. Animal studies and treatment regimens All animal experiments were approved by the THZ1 Institutional Animal Care and Use Committee (IACUC) of Augusta University. An equal number of male and female six-week-old NOD.Cg-(NSG) mice were purchased from the Jackson Laboratory (Bar Harbor, ME). An orthotopic tongue tumor model was generated as described previously [3]. Briefly, 1 105 luciferase-containing HNSCC cells were suspended in 50?l of PBS/Matrigel (3:1) and injected.
