(20S) Ginsenoside Rh2-Activated, Distinct Apoptosis Pathways in Highly and Poorly Differentiated Human Esophageal Cancer Cells.

Ginsenoside Rh2 (G-Rh2), a rare ginsenoside isolated from red ginseng, has considerable anti-cancer activity and induces apoptosis in a variety of cancer cells, but its activity in esophageal cancer cells is unclear. In this study, we examined the cytotoxic activity of (20S) G-Rh2 in highly differentiated esophageal squamous ECA109 cells and poorly differentiated esophageal squamous TE-13 cells. (20S) G-Rh2 exerted intense cytotoxicity in ECA109 and TE-13 cells with an IC50 of 2.9 and 3.7 µg/mL, respectively. After treatment with G-Rh2, Bcl-2, and Bcl-xL, the two main anti-apoptosis Bcl-2 family proteins upregulated, and Bax and Bak, the two key pro-apoptosis proteins translocated to mitochondria in both cell lines. At the same time, cytochrome c and Smac released from mitochondria, followed by caspase-9 activation, indicating that a mitochondria-mediated intrinsic apoptosis pathway was activated in both cell lines upon treatment with (20S) G-Rh2. It is noteworthy that (20S) G-Rh2 upregulated the transcription and protein expression of two death receptors, Fas and DR5, and subsequently activated Caspase-8 in the TE-13 cells but not in the ECA109 cells. Taken together, we demonstrated the potent anti-esophageal cancer cell activity of (20S) G-Rh2 and showed its working mechanism in two differentiated esophageal cancer cells, which can provide important evidence for developing an effective strategy for anti-esophageal cancer treatment.

Carbon Nanotubes Enabling Highly Efficient Cell Apoptosis by Low-Intensity Nanosecond Electric Pulses via Perturbing Calcium Handling.

Effective induction of targeted cancer cells apoptosis with minimum side effects has always been the primary objective for anti-tumor therapy. In this study, carbon nanotubes (CNTs) are employed for their unique ability to target tumors and amplify the localized electric field due to the high aspect ratio. Highly efficient and cancer cell specific apoptosis is finally achieved by combining carbon nanotubes with low intensity nanosecond electric pulses (nsEPs). The underlying mechanism may be as follows: the electric field produced by nsEPs is amplified by CNTs, causing an enhanced plasma membrane permeabilization and Ca2+ influx, simultaneously triggering Ca2+ release from intracellular storages to cytoplasm in a direct/indirect manner. All the changes above lead to excessive mitochondrial Ca2+ uptake. Substructural damage and obvious mitochondria membrane potential depolarization are caused subsequently with the combined action of numerously reactive oxygen species production, ultimately initiating the apoptotic process through the translocation of cytochrome c to the cytoplasm and activating apoptotic markers including caspase-9 and -3. Thus, the combination of nanosecond electric field with carbon nanotubes can actually promote HCT116 cell death via mitochondrial signaling pathway-mediated cell apoptosis. These results may provide a new and highly efficient strategy for cancer therapy.

Ginsenoside Rb 1: A novel therapeutic agent in Staphylococcusaureus-induced Acute Lung Injury with special reference to Oxidative stress and Apoptosis.

Acute lung injury (ALI) is considered as an uncontrolled inflammatory response that can leads to acute respiratory distress syndrome (ARDS), which limits the therapeutic strategies. Ginsenosides Rb1 (Rb1), an active ingredient obtained from Panax ginseng, possesses a broad range of pharmacological and medicinal properties, comprising the anti-inflammatory, anti-oxidant, and anti-tumor activities. Therefore, the purpose of the present study was to investigate the protective effects of Rb1 against S. aureus-induced (ALI) through regulation of Nuclear factor erythroid 2-related factor 2 (Nrf2) and mitochondrial-mediated apoptotic pathways in mice (in-vivo), and RAW264.7 cells (in-vitro). For that purpose, forty Kunming mice were randomly assigned into four treatment groups; (1) Control group (phosphate buffer saline (PBS); (2) S. aureus group; (3) S. aureus + Rb1 (20 mg/kg) group; and (4) Rb1 (20 mg/kg) group. The 20 µg/mL dose of Rb1 was used in RAW264.7 cells. In the present study, we found that Rb1 treatment reduced ALI-induced oxidative stress via suppressing the accumulation of malondialdehyde (MDA) and myeloperoxidase (MPO) and increase the antioxidant enzyme activities of superoxidase dismutase 1 (SOD1), Catalase (CAT), and glutathione peroxidase 1 (Gpx1). Similarly, Rb1 markedly increased messenger RNA (mRNA) expression of antioxidant genes (SOD1, CAT and Gpx1) in comparison with ALI group. The histopathological results showed that Rb1 treatment ameliorated ALI-induced hemorrhages, hyperemia, perivascular edema and neutrophilic infiltration in the lungs of mice. Furthermore, Rb1 enhanced the antioxidant defense system through activating the Nrf2 signaling pathway. Our findings showed that Rb1 treated group significantly up-regulated mRNA and protein expression of Nrf2 and its downstream associated genes down-regulated by ALI in vivo and in vitro. Moreover, ALI significantly increased the both mRNA and protein expression of mitochondrial-apoptosis-related genes (Bax, caspase-3, caspase-9, cytochrome c and p53), while decreased the Bcl-2. In addition, Rb1 therapy significantly reversed the mRNA and protein expression of these mitochondrial-apoptosis-related genes, as compared to the ALI group in vivo and in vitro. Taken together, Rb1 alleviates ALI-induced oxidative injury and apoptosis by modulating the Nrf2 and mitochondrial signaling pathways in the lungs of mice.

Pseudolaric acid B inhibits gastric cancer cell metastasis in vitro and in haematogenous dissemination model through PI3K/AKT, ERK1/2 and mitochondria-mediated apoptosis pathways.

Pseudolaric acid B (PAB) is the major bioactive constituent in the root bark of Pseudolarix kaempferi and has been reported to have cytotoxicity against tumor cells. Our in vivo experiments showed that PAB could inhibit gastric cancer cell lung metastasis in a nude mouse haematogenous dissemination model. To evaluate the anti-metastasis mechanism of PAB in gastric cancer cells, cytological experiments were performed. The results showed that PAB could inhibit the adhesion ability to matrigel, migration, invasion and colony formation ability of BGC-823 and MKN-45 cells. Western blot further confirmed that the inhibitory effects of PAB on anti-metastasis may involve regulating the expression of the metastasis-related proteins MMP-9, HIF-1α, VEGF, VEGFR2, E-Cadherin and Ezrin. We obtained further proof that PAB which could be used as a multi-targeted agent to inhibit the PI3K/AKT, ERK1/2 and mitochondria-mediated apoptosis pathways and consequently suppress tumor growth and metastasis. Our experiments suggest that PAB-induced effects may have novel therapeutic applications for the treatment of gastric cancer.

Cytotoxicity induced by fine particulate matter (PM2.5) via mitochondria-mediated apoptosis pathway in human cardiomyocytes.

Although the strongly causal associations were between fine particulate matter (PM2.5) and cardiovascular disease, the toxic effect and potential mechanism of PM2.5 on heart was poorly understood. Thus, the aim of this study was to evaluate the cardiac toxicity of PM2.5 exposure on human cardiomyocytes (AC16). The cell viability was decreased while the LDH release was increased in a dose-dependent way after AC16 exposed to PM2.5. The reactive oxygen species (ROS) generation and production of malondialdehyde (MDA) were increased followed by the decreasing in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The damage of mitochondria was observed by ultra-structural analysis and MMP measurement. The apoptotic rate of AC16 were markedly elevated which was triggered by PM2.5. In addition, the proteins involved in mitochondria- mediated apoptosis pathway were measured. The protein levels of Caspase-3, Caspase-9 and Bax were up-regulated while the anti-apoptotic protein, Bcl-2 was down-regulated after AC16 exposed to PM2.5. In summary, our results demonstrated that mitochondria-mediated apoptosis pathway played a critical role in PM2.5-induced myocardial cytotoxicity in AC16, which suggested that PM2.5 may contribute to cardiac dysfunction.

Cytotoxicity induced by fine particulate matter (PM2.5) via mitochondria-mediated apoptosis pathway in rat alveolar macrophages.

Although positive associations exist between ambient particulate matter (PM2.5; diameter ≤ 2.5 µm) and the morbidity and mortality rates for respiratory diseases, the biological mechanisms of the reported health effects are unclear. Considering that alveolar macrophages (AM) are the main cells responsible for phagocytic clearance of xenobiotic particles that reach the airspaces of the lungs, the purpose of this study was to investigate whether PM2.5 induced AM apoptosis, and investigate its possible mechanisms. Freshly isolated AM from Wistar rats were treated with extracted PM2.5 at concentrations of 33, 100, or 300 µg/mL for 4 h; thereafter, the cytotoxic effects were evaluated. The results demonstrated that PM2.5 induced cytotoxicity by decreasing cell viability and increasing lactate dehydrogenase (LDH) levels in AMs. The levels of reactive oxygen species (ROS) and intracellular calcium cations (Ca2+) markedly increased in higher PM2.5 concentration groups. Additionally, the apoptotic ratio increased, and the apoptosis-related proteins BCL2-associated X (Bax), caspase-3, and caspase-9 were upregulated, whereas B cell lymphoma-2 (Bcl-2) protein levels were downregulated following PM2.5 exposure. Cumulative findings showed that PM2.5 induced apoptosis in AMs through a mitochondrial-mediated pathway, which indicated that PM2.5 plays a significant role in lung injury diseases.

Silica - A trace geogenic element with emerging nephrotoxic potential.

Silica is a trace-geogenic compound with limited-bioavailability. It inflicts health-perils like pulmonary-silicosis and chronic kidney disease (CKD), when available via anthropogenic-disturbances. Amidst silica-imposed pathologies, pulmonary toxicological-mechanisms are well-described, ignoring the renal-pathophysiological mechanisms. Hence, the present-study aimed to elucidate cellular-cum-molecular toxicological-mechanisms underlying silica-induced renal-pathology in-vitro. Various toxicity-assessments were used to study effects of silica on the physiological-functions of HK-cells (human-kidney proximal-tubular cells - the toxin's prime target) on chronic (1-7 days) sub-toxic (80 mg/L) and toxic (100-120 mg/L) dosing. Results depicted that silica triggered dose-cum-time dependent cytotoxicity/cell-death (MTT-assay) that significantly increased on long-term dosing with ≥100 mg/L silica; establishing the nephrotoxic-potential of this dose. Contrarily, insignificant cell-death on sub-toxic (80 mg/L) dosing was attributed to rapid intracellular toxin-clearance at lower-doses preventing toxic-effects. The proximal-tubular (HK-cells) cytotoxicity was found to be primarily mediated by silica-triggered incessant oxidative-stress (elevated ROS).·This enhanced ROS inflicted severe inflammation and subsequent fibrosis, evident from increased pro-inflammatory-cum-fibrogenic cytokines generation (IL-1ß, IL-2, IL-6, TNF-α and TGF-ß). Simultaneously, ROS induced persistent DNA-damage (Comet-assay) that stimulated G2/M arrest for p53-mediated damage-repair, aided by checkpoint-promoter (Chk1) activation and mitotic-inducers (i.e. Cdc-25, Cdk1, cyclinB1) inhibition. However, DNA-injuries surpassed the cellular-repair, which provoked the p53-gene to induce mitochondrial-mediated apoptotic cell-death via activation of Bax, cytochrome-c and caspase-cascade (9/3). This persistent apoptotic cell-death and simultaneous incessant inflammation culminated in the development of tubular-atrophy and fibrosis, the major pathological-manifestations of CKD. These findings provided novel-insights into the pathological-mechanisms (cellular and molecular) of silica-induced CKD, inflicted on chronic toxic-dosing (≥100 mg/L).Thereby, encouraging the development of therapeutic-strategies (e.g. anti-oxidant treatment) for specific molecular-targets (e.g. ROS) to retard silica-induced CKD-progression, for reduction in the global-CKD burden.