Plasma Membrane

Example 6

In order to confirm the anticancer effect of the combined administration of OTS-412 and GCV, the cytotoxicity according to the administration of OTS-412 and GCV was evaluated in two human lung cancer cell lines, A549 and NCI-H460 cancer cell lines, and two human colorectal cancer cell lines, HT-29 and HCT-116 cancer cell lines.

Specifically, A549, NCI-H460, HT-29 and HCT-116 cancer cell lines were infected with OTS-412 at 0.01, 0.1 or 1 MOI. Three infected cancer cell lines (A549, NCI-H460, and HT-29) were treated with 100 M GCV, and the infected HCT-116 cancer cell line, with 50 M GCV. The cells were cultured for 72 hours and analyzed for cytotoxicity using CCK8 (Cell Counting Kit 8).

As a result, in NCI-H460 and HCT-116 cancer cell lines, the viability of cancer cells treated with the combination of OTS-412 and GCV was significantly lower than that of cancer cells treated with OTS-412 alone. On the other hand, in A549 and HT-29 cancer cell lines, no significant difference was observed between the viability of cancer cells treated with the combination of OTS-412 and GCV and that of the cancer cells treated with OTS-412 alone. This result demonstrates the additional cytotoxic effect by GCV as well as the direct cancer cell death by OTS-412 (FIG. 9).

In addition, the apoptosis and necrosis according to the combined administration of OTS-412 and GCV were confirmed by flow cytometry (FACS). Specifically, A549 and NCI-H460 cell lines were treated with GCV alone, OTS-412 alone, or a combination of OTS-412 and GCV, respectively, and the cells were subjected to Annexin V/PI staining followed by flow cytometry. At this time, the viability of cell was determined based on the facts that: both Annexin V and PI are negative in living cells; Annexin V is positive in the early stage of apoptosis, wherein the permeability of cell membrane changes; and both Annexin V and PI are positive at the end of apoptosis, wherein the nucleus is exposed by destruction of the cell membrane.

As a result, the apoptosis by treatment with GCV alone was not confirmed. However, when A549 cells were treated with OTS-412 alone, the apoptosis rate was observed as 19.64%, and with combined treatment of OTS-412 and GCV, 35.06%. In addition, when NCI-H460 cells were treated with OTS-412 alone, the apoptosis rate was observed as 6.58%, and with combined treatment of OTS-412 and GCV, 12.78% (FIG. 10). In addition, FACS results were quantified and compared with each other. As a result, an additional toxic effect by GCV was confirmed, compared to the group treated with OTS-412 alone (FIG. 11).

Example 1

To generate an attenuated strain of P. aeruginosa for production of alginate, the following virulence factor genes were sequentially deleted from the chromosome of the wild-type strain PAO1: toxA, plcH, phzM, wapR, and aroA. toxA encodes the secreted toxin Exotoxin A, which inhibits protein synthesis in the host by deactivating elongation factor 2 (EF-2). plcH encodes the secreted toxin hemolytic phospholipase C, which acts as a surfactant and damages host cell membranes. phzM encodes phenazine-specific methyltransferase, an enzyme required for the production of the redox active, pro-inflammatory, blue-green secreted pigment, pyocyanin. wapR encodes a rhamnosyltransferase involved in synthesizing O-antigen, a component of lipopolysaccharide (LPS) of the outer membrane of the organism. aroA encodes 3-phosphoshikimate 1-carboxyvinyltransferase, which is required intracellularly for aromatic amino acid synthesis. Deletion of aroA from the P. aeruginosa genome has previously been shown to attenuate the pathogen. Each gene was successfully deleted using a homologous recombination strategy with the pEX100T-Not1 plasmid. The in-frame, marker-less deletion of these five gene sequences was verified by Sanger sequencing and by whole genome resequencing (FIG. 1 and FIG. 8). This engineered strain was designated as PGN5. The whole genome sequence of PGN5 has been deposited to NCBI Genbank with an accession number of CP032541. All five in-frame gene deletions were detected and validated to be the deletion as designed using PCR (FIG. 7).

To verify gene deletion and attenuation of the PGN5 strain, the presence of the products of the deleted genes was measured and was either undetectable, or significantly reduced in the PGN5 strain. To test for the toxA gene deletion in PGN5, a Western blot analysis was performed for the presence of Exotoxin A in the culture medium. Exotoxin A secretion was detected in wild-type PAO1 control, but not in the PGN5 strain (FIG. 2A). To confirm the loss of plcH, hemolysis was assessed on blood agar. The hemolytic assay was carried out by streaking PAO1, PGN5, P. aeruginosa mucoid strain VE2, and a negative control, Escherichia coli strain BL21 on blood agar plates. A clear zone was observed surrounding PAO1 and VE2 cell growth, indicating complete (β-) hemolysis (FIG. 2B). In contrast, the blood agar remained red and opaque surrounding PGN5 and BL21 growth, indicating negligible or no hemolytic activity in these strains (FIG. 2B). To assess for deletion of phzM, the amount of pyocyanin secreted by PAO1 and PGN5 was extracted and measured. The amount of pyocyanin detected was significantly reduced in PGN5 (FIG. 2C). In fact, the difference in pigment production between PAO1 and PGN5 was immediately apparent on agar plates (FIG. 3A-3B). To test for wapR gene deletion, an LPS extraction was performed, followed by silver-stained SDS-PAGE and Western blot on the following strains: PAO1, PGN4 (PGN5 without aroA deletion), VE2, and PAO1_wbpL, which serves as a negative control due to a deletion in the O-antigen ligase gene, and thus produces no O-antigen. The presence of O-antigen was detected in PGN4, but the level of LPS banding was significantly reduced compared to the LPS banding profile observed in PAO1 and VE2 (FIG. 2D). Lastly, to test for aroA deletion, ELISA was performed to detect the presence of 3-phosphoshikimate 1-carboxyvinyltransferase in cell lysates prepared from PAO1 and PGN5. The ELISA results showed that the amount of 3-phosphoshikimate 1-carboxyvinyltransferase was significantly reduced in PGN5, compared to that in PAO1 (FIG. 2E). Additionally, the deletion of aroA resulted in slower growth in the PGN5 strain, a growth defect that was restored with the addition of 1 mg/mL of aromatic amino acids (W, Y, F) to the culture medium (data not shown).

Example 1

This example demonstrates that the binding interaction of βarr with the β2-adrenergic receptor (β2AR).

The binding of βarr to GPCRs is mainly initiated through an interaction with the phosphorylated receptor C terminus, and conformational changes induced in βarr by this interaction promote coupling to the receptor TM core, as shown in FIG. 1. Co-immunoprecipitation experiments confirmed that heterotrimeric Gs protein, but not βarr1, can interact with purified non-phosphorylated β2-adrenergic receptor (β2AR), as shown in FIG. 2A.

To verify that this apparent lack of interaction with βarr is not simply due to poor complex stability, two assays capable of detecting complex formation in situ were performed. First, competition radioligand binding was used to measure the allosteric effects of transducers on ligand binding to the receptor. As described by the ternary complex model, first for G proteins and later for βarrs, ligand-induced changes in receptor conformation enhance the binding and affinity of transducers, which reciprocally increase ligand affinity by stabilizing an active receptor state (De Lean A, et al. (1980) J Biol Chem 255(15):7108-7117., Gurevich V V, et al. (1997) J Biol Chem 272(46):28849-28852). When wild-type (WT) β2AR was reconstituted in high-density lipoprotein (HDL) particles to mimic a cellular membrane environment (Denisov I G & Sligar S G (2016) Nat Struct Mol Biol 23(6):481-486), G protein enhanced the affinity of the full agonist isoproterenol for non-phosphorylated HDL-β2AR by nearly 1000-fold, as expected, but βarr1 had no effect even at micromolar concentrations, as shown in FIG. 2B.

Second, to directly monitor β2AR conformational changes associated with activation, the C265 at the cytoplasmic end of TM6 was labeled with monobromobimane, an environmentally sensitive fluorophore. Receptor activation leads to an outward movement of TM6 that places the bimane label in a more solvent-exposed position, causing a decrease in fluorescence and a shift in λmax (Yao X J, et al. (2009) Proc Natl Acad Sci USA 106(23):9501-9506). Indeed, isoproterenol reduced β2AR-bimane fluorescence compared to control (DMSO), and addition of Gs but not βarr1 further attenuated fluorescence, as shown in FIG. 2C.

The results of this example demonstrate that non-phosphorylated β2AR fails to form a productive interaction with βarr.