Resonance light scattering technique as a new tool to determine the binding mode of anticancer drug oridonin to DNA

A Novel Solubility-Enhanced Rubusoside-Based Micelles for Increased Cancer Therapy

Many anti-cancer drugs have a common problem of poor solubility. Increasing the solubility of the drugs is very important for its clinical applications. In the present study, we revealed that the solubility of insoluble drugs was significantly enhanced by adding rubusoside (RUB). Further, it was demonstrated that RUB could form micelles, which was well characterized by Langmuir monolayer investigation, transmission electron microscopy, atomic-force microscopy, and cryogenic transmission electron microscopy. The RUB micelles were ellipsoid with the horizontal distance of ~25 nm and vertical distance of ~1.2 nm. Insoluble synergistic anti-cancer drugs including curcumin and resveratrol were loaded in RUB to form anti-cancer micelles RUB/CUR + RES. MTT assay showed that RUB/CUR + RES micelles had more significant toxicity on MCF-7 cells compared to RUB/CUR micelles + RUB/RES micelles. More importantly, it was confirmed that RUB could load other two insoluble drugs together for remarkably enhanced anti-cancer effect compared to that of RUB/one drug + RUB/another drug. Overall, we concluded that RUB-based micelles could efficiently load insoluble drugs for enhanced anti-cancer effect.

Geridonin, a novel derivative of oridonin, inhibits proliferation of MGC 803 cells both in vitro and in vivo through elevating the intracellular ROS

Objectives

To study the antitumour activity of a novel derivative of oridonin named geridonin in vitro and in vivo.

Methods

MTT and colony formation assay were used to test the cytotoxicity of geridonin; apoptosis, cell cycle arrest and the levels of reactive oxygen species were measured by flow cytometry; JC-1 staining assay was used to examine the mitochondrial membrane potential; the MGC 803 xenograft model was established to evaluate the antitumour effect of geridonin in vivo; H&E staining was performed for the histological analysis.

Key findings

In vitro, geridonin remarkably inhibited proliferation of gastrointestinal cancer cells including oesophageal, gastric, liver and colon cancers. On oesophageal, gastric cancer cells, geridonin displayed strong cytotoxicity than that of oridonin. In gastric cancer MGC 803 cells, geridonin triggered apoptosis through the mitochondrial pathway depending on caspase. In addition, geridonin sharply reduced the formation of cell colony, increased the intracellular levels of ROS and induced cell cycle arrest at G2/M phase. In vivo, geridonin delayed the growth of MGC 803 xenograft in athymic mice without obvious loss of bodyweight.

Conclusions

The novel derivative of oridonin, geridonin, inhibited the growth of human gastric cancer cells MGC 803 both in vitro and in vivo mainly via triggering apoptosis depending on elevating intracellular level of ROS.

Resonance light scattering detection of fructose bisphosphates using uranyl-salophen complex-modified gold nanoparticles as optical probe

In this paper, we report a resonance light scattering (RLS) method for the determination of fructose bisphosphates (FBPs) in water solution using fructose 1,6-bisphosphate (F-1,6-BP) as a model analyte without the procedure of extracting target analyte. The method used a type of modified gold nanoparticles (GNPs) as optical probe. The modified GNPs are uranyl-salophen-cysteamine-GNPs (U-Sal-Cy-GNPs) which are obtained through the acylation reaction of carboxylated salophen with cysteamine-capped GNPs (Cy-GNPs) to form Sal-Cy-GNPs and then the chelation reaction of uranyl with tetradentate ligand salophen in the Sal-Cy-GNPs. A FBP molecule is used easily to connect two U-Sal-Cy-GNPs to cause the aggregation of the GNPs by utilizing the specific affinity of uranyl-salophen complex to phosphate group, resulting in the production of strong RLS signal from the system. The amount of FBPs can be determined through detecting the RLS intensity change of the system. A linear range was found to be 2.5 to 75 nmol/L with a detection limit of 0.91 nmol/L under optimal conditions. The method has been successfully used to determine FBPs in real samples with the recoveries of 96.5-103.5 %.

Resonance light scattering spectroscopy of procyanidin-CPB-DNA ternary system and its potential application

A new method for the determination of calf thymus DNA at nanogram level was proposed based on the enhanced resonance light scattering (RLS) signals of DNA in the presence of procyanidin and cetylpyridinium bromide dihydrate (CPB). Under the experimental conditions, the RLS intensity of DNA at 291.0 nm was greatly enhanced by procyanidin-CPB at pH 7.0. There was a good linear relationship (r=0.9993) between the enhanced RLS intensity (ΔI(RLS)) and DNA concentration of 0.0084-3.36 μg mL(-1). The limit of detection (LOD) was 2.27 ng mL(-1) (3S0/S). Three synthetic DNA samples were measured with satisfactory, and the recovery was 102.3-107.2%.

Thermodynamic investigation of the interaction between the [(η6-p-cymene)Ru(benzaldehyde-N4-phenylthiosemicarbazone)Cl]Cl anticancer drug and ctDNA: multispectroscopic and electrochemical studies

The interaction between the [(η⁶-p-cymene)Ru(benzaldehyde-N⁴-phenylthiosemicarbazone)Cl]Cl anticancer drug and ctDNA was systematically investigated by multispectroscopic and electrochemical studies.

Partial intercalative binding of the food colorant erythrosine to herring sperm DNA

Erythrosine partially inserts into the G–C rich region of hsDNA and induces moderate conformational perturbation of the DNA.

A sensitive quantum dots-based "OFF-ON" fluorescent sensor for ruthenium anticancer drugs and ctDNA

In this contribution, a simple and sensitive fluorescent sensor for the determination of both the three ruthenium anticancer drugs (1 to 3) and calf thymus DNA (ctDNA) was established based on the CdTe quantum dots (QDs) fluorescence "OFF-ON" mode. Under the experimental conditions, the fluorescence of CdTe QDs can be effectively quenched by ruthenium anticancer drugs because of the surface binding of these drugs on CdTe QDs and the subsequent photoinduced electron transfer (PET) process from CdTe QDs to ruthenium anticancer drugs, which render the system into fluorescence "OFF" status. The system can then be "ON" after the addition of ctDNA which brought the restoration of CdTe QDs fluorescence intensity, since ruthenium anticancer drugs broke away from the surface of CdTe QDs and inserted into double helix structure of ctDNA. The fluorescence quenching effect of the CdTe QDs-ruthenium anticancer drugs systems was mainly concentration dependent, which could be used to detect three ruthenium anticancer drugs. The limits of detection were 5.5 × 10(-8) M for ruthenium anticancer drug 1, 7.0 × 10(-8) M for ruthenium anticancer drug 2, and 7.9× 10(-8) M for ruthenium anticancer drug 3, respectively. The relative restored fluorescence intensity was directly proportional to the concentration of ctDNA in the range of 1.0 × 10(-8) M ∼ 3.0 × 10(-7) M, with a correlation coefficient (R) of 0.9983 and a limit of detection of 1.1 × 10(-9) M. The relative standard deviation (RSD) for 1.5 × 10(-7) M ctDNA was 1.5% (n = 5). There was almost no interference to some common chemical compounds, nucleotides, amino acids, and proteins. The proposed method was applied to the determination of ctDNA in three synthetic samples with satisfactory results. The possible reaction mechanism of CdTe QDs fluorescence "OFF-ON" was further investigated. This simple and sensitive approach possessed some potential applications in the investigation of interaction between drug molecules and DNA.