A novel ent-kaurane diterpenoid analog, DN3, selectively kills human gastric cancer cells via acting directly on mitochondria

Cyclophilin D: Guardian or Executioner for Tumor Cells?

Cyclophilin D (CypD) is a peptide-proline cis-trans isomerase (PPIase) distributed in the mitochondrial matrix. CypD regulates the opening of the mitochondrial permeability conversion pore (mPTP) and mitochondrial bioenergetics through PPIase activity or interaction with multiple binding partners in mitochondria. CypD initially attracted attention due to its regulation of mPTP overopening-mediated cell death. However, recent studies on the effects of CypD on tumors have shown conflicting results. Although CypD has been proven to promote the aerobic glycolysis in tumor cells, its regulation of malignant characteristics such as the survival, invasion and drug resistance of tumor cells remains controversial. Here, we elaborate the main biological functions of CypD and its relationships with tumor progression identified in recent years, focusing on the dual role of CypD in tumors.

Design, Hemiysnthesis, crystal structure and anticancer activity of 1, 2, 3-triazoles derivatives of totarol

A new series of diverse triazoles linked to the hydroxyl group of totarol were synthesized using click chemistry approach. The structures of these compounds were elucidated by HRMS, IR and NMR spectroscopy. The structure of compound 3 g was also confirmed by x-ray single crystal diffraction. The cytotoxicity of these compounds was evaluated by the MTT method against four cancer cell lines, including fibrosarcoma HT-1080, lung carcinoma A-549 and breast adenocarcinoma (MDA-MB-231 and MCF-7), and the results indicated that all compounds showed weak to moderate activities against all cancer cell lines with IC₅₀ values ranging from 14.44 to 46.25 μM. On the basis of our research the structure-activity relationships (SAR) of these compounds were discussed. This work provides some important hints for further structural modification of totarol towards developing novel and highly effective anticancer drugs respectively. It is interesting to note that compound 3 g indicated a very significant cytotoxicity against HT-1080 and A-549 cell lines. The molecular docking showed that compound 3 g activated the caspase-3 and inhibited tubulin by forming stable protein-ligand complexes.

VDAC1 as a target in cisplatin anti-tumor activity through promoting mitochondria fusion

Cisplatin is one of the most effective anti-cancer drugs, but its efficacy is limited by the development of resistance. Previous studies have shown that mitochondria play critical roles in cisplatin cytotoxicity, however, the exact mechanism of mitochondria involved in cisplatin sensitivity has not been clarified. In this study, cisplatin triggered mitochondrial oxidative stress and the decrease of mitochondria membrane potential in human cervical cancer cells. Then we screened a series of mitochondrial relevant inhibitors, including mitochondrial mPTP inhibitors DIDS and CsA, and mitochondrial respiratory complex inhibitors Rot and TTFA. Among these, only DIDS, as the inhibitor of mitochondrial outer membrane protein VDAC1, showed strong antagonism against cisplatin toxicity. DIDS mitigated cisplatin-induced MFN1-dependent mitochondrial fusion, mitochondrial dysfunction and oxidative damage. These findings demonstrated that VDAC1 may serve as a potential therapeutic target in the increase sensitivity of cisplatin, which provides an attractive pharmacological therapy to improve the effectiveness of chemotherapy.

The study on the interactions of two 1,2,3-triazoles with several biological macromolecules by multiple spectroscopic methodologies and molecular docking

1-(4-chlorophenyl)-5-phenyl-1H-1,2,3-triazole (CPTC) and 5-(3-chlorophenyl) -1-phenyl-1H-1,2,3-triazole (PCTA) are two new derivatives of 1,2,3-triazole. Their structural and spectral properties were characterized by density functional theory calculations (DFT). The binding properties of CPTC or PCTA with several typical biomacromolecules such as human serum albumin (HSA), bovine hemoglobin (BHb), human immunoglobulin (HIgG) or DNA were investigated by molecular docking and multiple spectroscopic methodologies. The different parameters including binding constants and thermodynamic parameters for CPTC/PCTA-HSA/BHb/HIgG/DNA systems were obtained based on various fluorescence enhancement or quenching mechanisms. The results of binding constants indicated that there were the strong interactions between two triazoles and four biological macromolecules due to the higher order of magnitude between 10³ and 10⁵. The values of thermodynamic parameters revealed that the binding forces for these systems are mainly hydrophobic interactions, electrostatic force, or hydrogen bond, respectively, which are in agreement with the results of molecular docking to a certain extent. Moreover, the information from synchronous, 3D fluorescence and UV-Vis spectroscopies proved that two compounds CPTC and PCTA could affect the microenvironment of amino acids residues of three kinds of proteins. Based on the above experimental results, a comparison of the interaction mechanisms for CPTC/PCTA-proteins/DNA systems have been performed in view of their different molecular structures, which is beneficial for the further research in order to design them as the novel drugs.

Electroacupuncture pretreatment alleviates myocardial injury through regulating mitochondrial function

Background

Electroacupuncture is well known for its advantageous neuroanalgesic and therapeutic effects on myocardial ischemia–reperfusion injury. The purpose of the present research was to verify whether electroacupuncture can alleviate bupivacaine-induced myocardial injury.

Methods

Specific pathogen-free Wistar rats were used to establish the bupivacaine-induced myocardial injury model. Western blot, PCR, transmission electron microscope and enzyme-linked immunosorbent (ELISA) methods were used to evaluate bupivacaine-induced structure injury and dysfunction of the mitochondria as well as the alleviating effects of lipid emulsion, acupoint injection, and electroacupuncture pre-treatment of the oxidase stress response.

Results

Bupivacaine caused structural damage, degradation, and swelling of mitochondria. Furthermore, it reduced adenosine triphosphate (ATP) synthesis and impaired energy metabolism in the mitochondria. Structural and functional impairment of the mitochondria was alleviated via lipid emulsion injection, acupoint injection, and electroacupuncture pre-treatment. Electroacupuncture pre-treatment of PC6 yielded a greater alleviating effect than others approaches. Following electroacupuncture pre-treatment of PC6 point, the number of mitochondria increased; apoptosis was reduced, enzymatic activity of cytochrome C oxidase (COX) and superoxide dismutase and expression of uncoupling protein 2, voltage-dependent anion channel 1, and Bcl 2 were upregulated and SLC25A6, MDA levels were downregulated. Additionally, our findings indicated that electroacupuncture pre-treatment of PC6 point exerted an effect on the mitochondria via the mitochondrial-transcription-factor-A/nuclear-respiratory-factor-1/proliferator-activated-receptor-gamma-coactivator-1 pathway.

Conclusion

The present study revealed that electroacupuncture pre-treatment of PC6 could effectively alleviate bupivacaine-induced myocardial mitochondrial damage, thereby providing a theoretical basis for clinical studies and applications of this treatment method.

T-2 toxin cytotoxicity mediated by directly perturbing mitochondria in human gastric epithelium GES-1 cells

T-2 toxin is one of the most toxic trichothecenes and harmful to human health and animal husbandry. The mechanism underlying its growth suppression remains unclear, especially for mitochondrial damage in human gastric epithelial cells. In the present study, we investigated cell death caused by T-2 toxin in a human gastric epithelial cell line (GES-1) and the possible mechanism of T-2-induced cytotoxicity. T-2 strongly reduced the viability of GES-1 cells in a time- and dose-dependent manner within a small range of concentrations. However, when the concentrations of T-2 were >40 nM, there was no concentration dependence, only time dependence. Moreover, T-2 induced apoptosis, with the activation of caspase-3 in GES-1 and mitochondrial membrane potential (MMP) decrease and cytochrome c release. T-2 also resulted in the accumulation of reactive oxygen species (ROS) and DNA damage with a positive signal of p-H2A.X in GES-1 cells. While T-2 caused a MMP decrease, DNA damage and cell death were not blocked by pretreatment with 3 mM glutathione (GSH), a typical scavenger of ROS. The induction of mitochondrial permeability transition pore (mPTP) regulators voltage-dependent anion channel (VDAC1) and cyclophilin D (CypD) were also observed in T-2-treated cells. Interestingly, cyclosporine A (CsA), a CypD inhibitor, significantly reversed the drop in MMP and the DNA damage, as well as ROS accumulation caused by T-2. Additionally, GES-1 cell death could also be protected to some extent by 4, 4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS), an inhibitor of VDAC1, especially the combination of CsA and DIDS, and 3 mM GSH could further enhance the effect of CsA + DIDS on cell viability. In conclusion, our present findings indicate that the T-2 induced MMP decrease, DNA damage and cell death, as well as ROS accumulation in GES-1 cells, starts with T-2 directly perturbing the mitochondria triggering ROS generation by acting on CypD and VDAC1. This study presents a new viewpoint for evaluating the toxicity of T-2 toxin.