Brazilin Actuates Ferroptosis in Breast Cancer Cells via p53/SLC7A11/GPX4 Signaling Pathway.

OBJECTIVE: To investigate the mechanism of induction of ferroptosis by brazilin in breast cancer cells. METHODS: Breast cancer 4T1 cells were divided into 6 groups: control, brazilin 1/2 half maximal inhibitory concentration (IC50), IC50, 2×IC50, erastin (10 µg/mL) and capecitabine (10 µg/mL) groups. The effect of brazilin on the proliferation of 4T1 cells was detected by cell counting kit-8 assay, and the treatment dose of brazilin was screened. The effect of brazilin on the mitochondrial morphology of 4T1 cells, and the mitochondrial damage was evaluated under electron microscopy. The levels of Fe2+, reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase 4 (GPX4) were estimated using various detection kits. The invasion and migration abilities of 4T1 cells were detected by scratch assay and transwell assay. The expressions levels of tumor protein p53, solute carrier family 7 member 11 (SLC7A11), GPX4 and acyl-CoA synthetase long-chain family member 4 (ACSL4) proteins were quantified by Western blot assay. RESULTS: Compared to the control group, the 10 (1/2 IC50), 20 (IC50) and 40 (2×IC50) µg/mL brazilin, erastin, and capecitabine groups showed a significant decrease in the cell survival rate, invasion and migration abilities, GSH, SLC7A11 and GPX4 protein expression levels, and mitochondrial volume and ridge (P<0.05), and a significant increase in the mitochondria membrane density, Fe2+, ROS and MDA levels, and p53 and ACSL4 protein expression levels (P<0.05). CONCLUSIONS: Brazilin actuated ferroptosis in breast cancer cells, and the underlying mechanism is mainly associated with the p53/SLC7A11/GPX4 signaling pathway.

[Molecular mechanisms of Gupi Xiaoji decoction inducing apoptosis of human hepatoma HepG2 cells].

Objective: To investigate the molecular mechanisms of Gupi Xiaoji decoction on apoptosis of human hepatoma cells HepG2. Methods: HepG2 cells were divided into 4 groups: control group (Control), blank serum group (Blank), Gupi Xiaoji Yin serum group (GPXJY) and cisplatin group (Positive). Eight duplicate holes were set in each group. After treated with Gupi Xiaoji Decoction-containing serum or cisplatin for 24 hours, the cell viability, the number of viable cells, the state of apoptosis, the cell cycle and the mitochondrial membrane potential were detected, and the level of lipid peroxidation (MDA) and glycolysis rate of the cells were detected. The expressions of apoptotic Bax, Bcl-2, and Caspase-3 proteins, and the contents of triacylglycerol (TG), cholesterol (TC), pyruvate and glucose in the cell supernatant were detected. Results: Compared with the control group, in the GPXJY group, the inhibition rate was increased (P＜0.05), the number of cells was decreased, the number of apoptosis-positive cells was increased (P＜0.01), the number of cells in the G1 phase was increased significantly (P＜0.05), and the cell membrane potential was decreased (P＜0.05,P＜0.01), the glycolytic function was inhibited significantly, the MDA level was increased, the expressions of Bax and Caspase-3 in the GPXJY group were increased, and the expression of Bcl-2 was decreased (P＜0.05, P＜0.01). In cell supernatant, the TC, TG and glucose contents were decreased significantly, and the pyruvate content was increased significantly (P＜0.05,P＜0.01). Conclusion: Gupi Xiaoji Decoction can induce apoptosis of HepG2 cells and may play a role in energy metabolism.

Molecular Mechanisms of Chondrocyte Proliferation and Differentiation.

Cartilage is a kind of connective tissue that buffers pressure and is essential to protect joint movement. It is difficult to self-recover once cartilage is damaged due to the lack of blood vessels, lymph, and nerve tissues. Repair of cartilage injury is mainly achieved by stimulating chondrocyte proliferation and extracellular matrix (ECM) synthesis. Cartilage homeostasis involves the regulation of multiple growth factors and the transduction of cellular signals. It is a very complicated process that has not been elucidated in detail. In this review, we summarized a variety of signaling molecules related to chondrocytes function. Especially, we described the correlation between chondrocyte-specific regulatory factors and cell signaling molecules. It has potential significance for guiding the treatment of cartilage injury.

Highly Selective Production of Compound K from Ginsenoside Rd by Hydrolyzing Glucose at C-3 Glycoside Using ß-Glucosidase of Bifidobacterium breve ATCC 15700.

To investigate a novel ß-glucosidase from Bifidobacterium breve ATCC 15700 (BbBgl) to produce compound K (CK) via ginsenoside F2 by highly selective and efficient hydrolysis of the C-3 glycoside from ginsenoside Rd, the BbBgl gene was cloned and expressed in E. coli BL21. The recombinant BbBgl was purified by Ni-NTA magnetic beads to obtain an enzyme with specific activity of 37 U/mg protein using pNP-Glc as substrate. The enzyme activity was optimized at pH 5.0, 35°C, 2 or 6 U/ml, and its activity was enhanced by Mn2+ significantly. Under the optimal conditions, the half-life of the BbBgl is 180 h, much longer than the characterized ß-glycosidases, and the Km and Vmax values are 2.7 mM and 39.8 µmol/mg/min for ginsenoside Rd. Moreover, the enzyme exhibits strong tolerance against high substrate concentration (up to 40 g/l ginsenoside Rd) with a molar biotransformation rate of 96% within 12 h. The good enzymatic properties and gram-scale conversion capacity of BbBgl provide an attractive method for large-scale production of rare ginsenoside CK using a single enzyme or a combination of enzymes.