Acetylshikonin induces necroptosis via the RIPK1/RIPK3-dependent pathway in lung cancer.

Despite advances in therapeutic strategies, lung cancer remains the leading cause of cancer-related death worldwide. Acetylshikonin is a derivative of the traditional Chinese medicine Zicao and presents a variety of anticancer properties. However, the effects of acetylshikonin on lung cancer have not been fully understood yet. This study explored the mechanisms underlying acetylshikonin-induced cell death in non-small cell lung cancer (NSCLC). Treating NSCLC cells with acetylshikonin significantly reduced cell viability, as evidenced by chromatin condensation and the appearance of cell debris. Acetylshikonin has also been shown to increase cell membrane permeability and induce cell swelling, leading to an increase in the population of necrotic cells. When investigating the mechanisms underlying acetylshikonin-induced cell death, we discovered that acetylshikonin promoted oxidative stress, decreased mitochondrial membrane potential, and promoted G2/M phase arrest in lung cancer cells. The damage to NSCLC cells induced by acetylshikonin resembled results involving alterations in the cell membrane and mitochondrial morphology. Our analysis of oxidative stress revealed that acetylshikonin induced lipid oxidation and down-regulated the expression of glutathione peroxidase 4 (GPX4), which has been associated with necroptosis. We also determined that acetylshikonin induces the phosphorylation of receptor-interacting serine/threonine-protein kinase 1 (RIPK1)/RIPK3 and mixed lineage kinase domain-like kinase (MLKL). Treatment with RIPK1 inhibitors (necrostatin-1 or 7-Cl-O-Nec-1) significantly reversed acetylshikonin-induced MLKL phosphorylation and NSCLC cell death. These results indicate that acetylshikonin activated the RIPK1/RIPK3/MLKL cascade, leading to necroptosis in NSCLC cells. Our findings indicate that acetylshikonin reduces lung cancer cells by promoting G2/M phase arrest and necroptosis.

Hyperthermia increases HSP production in human PDMCs by stimulating ROS formation, p38 MAPK and Akt signaling, and increasing HSF1 activity.

BACKGROUND: Human placenta-derived multipotent cells (hPDMCs) are isolated from a source uncomplicated by ethical issues and are ideal for therapeutic applications because of their capacity for multilineage differentiation and proven immunosuppressive properties. It is known that heat shock preconditioning induces the upregulation of heat shock proteins (HSPs), which enhance survival and engraftment of embryonic stem cells (ESCs) during transplantation in live animal models, although whether heat shock preconditioning has the same effects in hPDMCs is unclear. METHODS: The hPDMCs were isolated from placenta of healthy donors. The cells were treated with heat shock (43 °C, 15 min), followed by evaluation of cell viability. Furthermore, the HSPs expression was assessed by Western blot, qPCR. The reactive oxygen species (ROS) production and signal pathway activation were determined by flow cytometry and Western blot, respectively. The regulatory pathways involved in HSPs expression were examined by pretreatment with chemical inhibitors, and siRNAs of MAPK, Akt, and heat shock factor 1 (HSF1), followed by determination of HSPs expression. RESULTS: This study demonstrates that heat shock treatment induced ROS generation and HPSs expression in hPDMCs. Heat shock stimulation also increased p38 MAPK and Akt phosphorylation. These effects were reduced by inhibitors of ROS, p38 MAPK and Akt. Moreover, we found that heat shock treatment enhanced nuclear translocation of the HSF1 in hPDMCs, representing activation of HSF1. Pretreatment of hPDMCs with ROS scavengers, SB203580 and Akt inhibitors also reduced the translocation of HSF1 induced by heat shock. CONCLUSIONS: Our data indicate that heat shock acts via ROS to activate p38 MAPK and Akt signaling, which subsequently activates HSF1, leading to HSP activation and contributing to the protective role of hPDMCs.

Highly efficient magnetic ablation and the contrast of various imaging using biocompatible liquid-metal gallium.

BACKGROUND: Although the powerful clinical effects of radiofrequency and microwave ablation have been established, such ablation is associated with several limitations, including a small ablation size, a long ablation time, the few treatment positioning, and biosafety risks. To overcome these limitations, biosafe and efficient magnetic ablation was achieved in this study by using biocompatible liquid gallium as an ablation medium and a contrast medium for imaging. RESULTS: Magnetic fields with a frequency (f) lower than 200 kHz and an amplitude (H) × f value lower than 5.0 × 109 Am-1 s-1 were generated using the proposed method. These fields could generate an ablation size of 3 cm in rat liver lobes under a temperature of approximately 300 °C and a time of 20 s. The results of this study indicate that biomedical gallium can be used as a contrast medium for the positioning of gallium injections and the evaluation of ablated tissue around a target site. Liquid gallium can be used as an ablation medium and imaging contrast medium because of its stable retention in normal tissue for at least 3 days. Besides, the high anticancer potential of gallium ions was inferred from the self-degradation of 100 µL of liquid gallium after around 21 days of immersion in acidic solutions. CONCLUSIONS: The rapid wireless ablation of large or multiple lesions was achieved through the simple multi-injection of liquid gallium. This approach can replace the currently favoured procedure involving the use of multiple ablation probes, which is associated with limited benefits and several side effects. METHODS: Magnetic ablation was confirmed to be highly efficient by the consistent results obtained in the simulation and in vitro tests of gallium and iron oxide as well as the electromagnetic specifics and thermotherapy performance comparison detailed in this study Ultrasound imaging, X-ray imaging, and magnetic resonance imaging were found to be compatible with the proposed magnetic ablation method. Self-degradation analysis was conducted by mixing liquid gallium in acidic solutions with a pH of approximately 5-7 (to imitate a tumour-containing microenvironment). X-ray diffraction was used to identify the gallium oxides produced by degraded gallium ions.

Artocarpin induces cell apoptosis in human osteosarcoma cells through endoplasmic reticulum stress and reactive oxygen species.

Osteosarcoma is a malignant primary bone tumor that responds poorly to both chemotherapy and radiation therapy. However, because of side effects and drug resistance in chemotherapy and the insufficiency of an effective adjuvant therapy for osteosarcoma, it is necessary to research novel treatments. This study was the first to investigate the anticancer effects of the flavonoid derivative artocarpin in osteosarcoma. Artocarpin induced cell apoptosis in three human osteosarcoma cell lines-U2OS, MG63, and HOS. Artocarpin was also associated with increased intracellular reactive oxygen species (ROS). Mitochondrial dysfunction was followed by the release of cytochrome c from mitochondria and accompanied by decreased antiapoptotic Bcl-2 and Bcl-xL and increased proapoptotic protein Bak and Bax. Artocarpin triggered endoplasmic reticulum (ER) stress, as indicated by changes in cytosol calcium levels and increased glucose-regulated protein 78 and 94 expressions, and also increased calpains expression and activity. Animal studies revealed a dramatic 40% reduction in tumor volume after 18 days of treatment. This study demonstrated a novel anticancer activity of artocarpin against human osteosarcoma cells and in murine tumor models. In summary, artocarpin significantly induced cell apoptosis through ROS, ER stress, mitochondria, and the caspase pathway, and may thus be a novel anticancer treatment for osteosarcoma.

Cytotoxic protobassic acid saponins from the kernels of Palaquium formosanum.

Bioassay guided fractionation and separation of the EtOH extract of the kernels of Palaquium formosanum against PC-3 cells via Sephadex LH-20 and reverse phase C-18 columns led to the isolation of 13 protobassic saponins. One of these saponins is new and was characterized as 3‴-O-rhamnopyranosyl-arganin C, a bisdesmoside of 16α-hydroxyprotobassic acid at the C-3 and C-28 positions. The structures of these compounds were determined on the basis of 1D NMR (1H, 13C), 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY), and selectively excited 1D TOCSY spectroscopic analyses and MS data, and comparison with literature data. Bioassay of these compounds and five additional compounds, isolated from Planchonella obovata leaf, against PC-3 prostate cancer cells indicated arganin C to be the most potent one with the IC50 value of 13.8 µM. Some structure and activity relationships were also drawn.

Hyperthermia induces apoptosis through endoplasmic reticulum and reactive oxygen species in human osteosarcoma cells.

Osteosarcoma (OS) is a relatively rare form of cancer, but OS is the most commonly diagnosed bone cancer in children and adolescents. Chemotherapy has side effects and induces drug resistance in OS. Since an effective adjuvant therapy was insufficient for treating OS, researching novel and adequate remedies is critical. Hyperthermia can induce cell death in various cancer cells, and thus, in this study, we investigated the anticancer method of hyperthermia in human OS (U-2 OS) cells. Treatment at 43 °C for 60 min induced apoptosis in human OS cell lines, but not in primary bone cells. Furthermore, hyperthermia was associated with increases of intracellular reactive oxygen species (ROS) and caspase-3 activation in U-2 OS cells. Mitochondrial dysfunction was followed by the release of cytochrome c from the mitochondria, and was accompanied by decreased anti-apoptotic Bcl-2 and Bcl-xL, and increased pro-apoptotic proteins Bak and Bax. Hyperthermia triggered endoplasmic reticulum (ER) stress, which was characterized by changes in cytosolic calcium levels, as well as increased calpain expression and activity. In addition, cells treated with calcium chelator (BAPTA-AM) blocked hyperthermia-induced cell apoptosis in U-2 OS cells. In conclusion, hyperthermia induced cell apoptosis substantially via the ROS, ER stress, mitochondria, and caspase pathways. Thus, hyperthermia may be a novel anticancer method for treating OS.

The novel phloroglucinol derivative BFP induces apoptosis of glioma cancer through reactive oxygen species and endoplasmic reticulum stress pathways.

Prenyl-phloroglucinol derivatives from hop plants have been shown to have anticancer activities. This study is the first to investigate the anticancer effects of the new phloroglucinol derivative (2,4-bis(4-fluorophenylacetyl)phloroglucinol; BFP). BFP induced cell death and anti-proliferation in three glioma, U251, U87 and C6 cells, but not in primary human astrocytes. BFP-induced concentration-dependently cell death in glioma cells was determined by MTT and SRB assay. Moreover, BFP-induced apoptotic cell death in glioma cells was measured by Hochest 33258 staining and fluorescence-activated cell sorter (FACS) of propidine iodine (PI) analysis. Treatment of U251 human glioma cells with BFP was also found to induce reactive oxygen species (ROS) generation, which was detected by a fluorescence dye used FACS analysis. Treatment of BFP also increased a number of signature endoplasmic reticulum (ER) stress markers glucose-regulated protein (GRP)-78, GRP-94, IRE1, phosphorylation of eukaryotic initiation factor-2α (eIF-2α) and up-regulation of CAAT/enhancer-binding protein homologous protein (CHOP). Moreover, treatment of BFP also increased the down-stream caspase activation, such as pro-caspase-7 and pro-caspase-12 degradation, suggesting the induction of ER stress. Furthermore, BFP also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Treatment of antioxidants, or pre-transfection of cells with GRP78 or CHOP siRNA reduced BFP-mediated apoptotic-related protein expression. Taken together, the present study provides evidences to support that ROS generation, GRP78 and CHOP activation are mediating the BFP-induced human glioma cell apoptosis.

DDTD, an isoflavone derivative, induces cell apoptosis through the reactive oxygen species/apoptosis signal-regulating kinase 1 pathway in human osteosarcoma cells.

Osteosarcoma is the most common primary bone tumor associated with childhood and adolescence. In the present study, we investigated the anticancer effect of a new isoflavone derivative, 3',4'-dichloro-3-(3,4-dichlorophenylacetyl)-2,4,6-trihydroxydeoxybenzoin (DDTD) in human osteosarcoma cells. DDTD induced cell apoptosis in human osteosarcoma cell lines (including: U2OS, MG-63, Saos2 and ROS 17/2.8). We found that the accumulation of reactive oxygen species is a critical mediator in DDTD-induced cell death. DDTD induced apoptosis signal-regulating kinase 1 (ASK1) dephosphorylation and its dissociation from 14-3-3. Treatment of osteosarcoma cells with DDTD induced p38 and p53 phosphorylation. Transfection with ASK1, mitogen activated protein kinase (MAPK) kinase (MKK)3/6, and p38 small interfering RNA (siRNA) antagonized the DDTD-induced cell apoptosis. DDTD also triggered the mitochondrial apoptotic pathway, as indicated by a change in Bax/Bcl2 ratio and Caspase-9 activation. Bax knockdown using a Bax siRNA strategy reduced Bax expression and subsequent cell death. In addition, transfection of cells with ASK1, MKK3/6, and p38 siRNA reduced DDTD-induced p38 activation, p53 phosphorylation and Bax expression. These results suggest that DDTD generates reactive oxygen species and activates the ASK1-MKK3/6-p38-p53-Bax pathway to cause osteosarcoma cell death.