OBJECTIVE: This study aims to determine the effect of S. crispus active fraction (F3) and its bioactive components on glycolysis in triple-negative breast cancer cells (MDA-MB-231).
METHODS: This study utilizes F3, lutein, β-sitosterol, and stigmasterol to be administered in MDA-MB-231 cells for measurement of antiglycolytic activities through cell poliferation, glucose uptake, and lactate concentration assays. Cell proliferation was assessed by MTT assay of MDA-MB-231 cells after treatment with F3 and its bioactive components lutein, β-sitosterol, and stigmasterol. The IC50 value in each compound was determined by MTT assay to be used in subsequent assays. The determination of glucose uptake activity and lactate concentration were quantified using fluorescence spectrophotometry.
RESULTS: Antiproliferative activities were observed for F3 and its bioactive components, with IC50 values of 100 µg/mL (F3), 20 µM (lutein), 25 µM (β-sitosterol), and 90 μM (stigmasterol) in MDA-MB-231 cells at 48 h. The percentage of glucose uptake and lactate concentration in MDA-MB-231 cells treated with F3, lutein, or β sitosterol were significantly lower than those observed in the untreated cells in a time-dependent manner. However, treatment with stigmasterol decreased the concentration of lactate without affecting the glucose uptake in MDA-MB-231 cells.
CONCLUSION: The antiglycolytic activities of F3 on MDA-MB-231 cells are attributed to its bioactive components.
METHODS: The three variants expressed by bacteria were investigated using substrate (omeprazole and 3- cyano-7-ethoxycoumarin[CEC]) and inhibitor (ketoconazole, fluoxetine, sertraline and loratadine) probes in enzyme assays along with molecular docking.
RESULTS: All alleles exhibited very low enzyme activity and affinity towards omeprazole and CEC (6.1% or less in intrinsic clearance). The inhibition studies with the four inhibitors, however, suggested that mutations in different variants have a tendency to cause enhanced binding (reduced IC50 values). The enhanced binding could partially be explained by the lower polar solvent accessible surface area of the inhibitors relative to the substrates. Molecular docking indicated that G91R, R335Q and F448L, the unique mutations in the alleles, have caused slight alteration in the substrate access channel morphology and a more compact active site cavity hence affecting ligand access and binding. It is likely that these structural alterations in CYP2C19 proteins have caused ligand-specific alteration in catalytic and inhibitory specificities as observed in the in vitro assays.
CONCLUSION: This study indicates that CYP2C19 variant selectivity for ligands was not solely governed by mutation-induced modifications in the active site architecture, but the intrinsic properties of the probe compounds also played a vital role.
RESULTS: In this study, pro-inflammatory macrophage was selected as the target cell due to its major roles in numerous inflammatory and autoimmune disorders. We aimed to construct macrophage-targeted recombinant immunotoxins by combining HALT-1 with anti-CD64-scFv in two orientations, and to assess whether their cytotoxic activity and binding capability could be preserved upon molecular fusion. The recombinant immunotoxins, HALT-1-scFv and scFv-HALT-1, were successfully constructed and expressed in Escherichia coli (E. coli). Our data showed that HALT-1 still exhibited significant cytotoxicity against CD64+ and CD64- cell lines upon fusion with anti-CD64 scFv, although it had half cytotoxic activity as compared to HALT-1 alone. As positioning HALT-1 at N- or C-terminus did not affect its potency, the two constructs demonstrated comparable cytotoxic activities with IC50 lower in CD64+ cell line than in CD64- cell line. In contrast, the location of targeting moieties anti-CD64 scFv at C-terminal end was crucial in maintaining the scFv binding capability.
CONCLUSIONS: HALT-1 could be fused with anti-CD64-scFv via a fsexible polypeptide linker. Upon the successful production of this recombinant HALT-1 scFv fusion protein, HALT-1 was proven effective for killing two human cell lines. Hence, this preliminary study strongly suggested that HALT-1 holds potential as the toxin moiety in therapeutic cell targeting.