A magneto-optical biochip for rapid assay based on the Cotton-Mouton effect of γ-Fe2O3@Au core/shell nanoparticles.

BACKGROUND: In the past decades, different diseases and viruses, such as Ebola, MERS and COVID-19, impacted the human society and caused huge cost in different fields. With the increasing threat from the new or unknown diseases, the demand of rapid and sensitive assay method is more and more urgent. RESULTS: In this work, we developed a magneto-optical biochip based on the Cotton-Mouton effect of γ-Fe2O3@Au core/shell magnetic nanoparticles. We performed a proof-of-concept experiment for the detection of the spike glycoprotein S of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The assay was achieved by measuring the magneto-optical Cotton-Mouton effect of the biochip. This magneto-optical biochip can not only be used to detect SARS-CoV-2 but also can be easily modified for other diseases assay. CONCLUSION: The assay process is simple and the whole testing time takes only 50 min including 3 min for the CM rotation measurement. The detection limit of our method for the spike glycoprotein S of SARS-CoV-2 is estimated as low as 0.27 ng/mL (3.4 pM).

Proteomic study reveals a co-occurrence of gallic acid-induced apoptosis and glycolysis in B16F10 melanoma cells.

Gallic acid (GA) has long been associated with a wide range of biological activities. In this study, its antitumor effect against B16F10 melanoma cells was demonstrated by MTT assay, cell migration assay, wound-healing assay, and flow cytometric analysis. GA with a concentration >200 µM shows apoptotic activity toward B16F10 cells. According to Western blotting data, overexpressions of cleaved forms of caspase-9, caspase-3, and PARP-1 and pro-apoptotic Bax and Bad, accompanied by underexpressed anti-apoptotic Bcl-2 and Bcl-xL indicate that GA induces B16F10 cell apoptosis via mitochondrial pathway. The 2-DE based comparative proteomics was further employed in B16F10 cells with and without GA treatment for a large-scale protein expression profiling. A total of 41 differential protein spots were quantified, and their identities were characterized using LC-MS/MS analysis and database matching. In addition to some regulated proteins that were associated with apoptosis, interestingly, some identified proteins involved in glycolysis such as glucokinase, α-enolase, aldolase, pyruvate kinase, and GAPDH were simultaneously up-regulated, which reveals that the GA-induced cellular apoptosis in B16 melanoma cells is associated with metabolic glycolysis.

13-acetoxysarcocrassolide induces apoptosis on human gastric carcinoma cells through mitochondria-related apoptotic pathways: p38/JNK activation and PI3K/AKT suppression.

13-acetoxysarcocrassolide (13-AC), an active compound isolated from cultured Formosa soft coral Sarcophyton crassocaule, was found to possess anti-proliferative and apoptosis-inducing activities against AGS (human gastric adenocarcinoma cells) gastric carcinoma cells. The anti-tumor effects of 13-AC were determined by MTT assay, colony formation assessment, cell wound-healing assay, TUNEL/4,6-Diamidino-2-phenylindole (DAPI) staining, Annexin V-fluorescein isothiocyanate/propidium iodide (PI) staining and flow cytometry. 13-AC inhibited the growth and migration of gastric carcinoma cells in a dose-dependent manner and induced both early and late apoptosis as assessed by flow cytometer analysis. 13-AC-induced apoptosis was confirmed through observation of a change in ΔΨm, up-regulated expression levels of Bax and Bad proteins, down-regulated expression levels of Bcl-2, Bcl-xl and Mcl-1 proteins, and the activation of caspase-3, caspase-9, p38 and JNK. Furthermore, inhibition of p38 and JNK activity by pretreatment with SB03580 (a p38-specific inhibitor) and SP600125 (a JNK-specific inhibitor) led to rescue of the cell cytotoxicity of 13-AC-treated AGS cells, indicating that the p38 and the JNK pathways are also involved in the 13-AC-induced cell apoptosis. Together, these results suggest that 13-AC induces cell apoptosis against gastric cancer cells through triggering of the mitochondrial-dependent apoptotic pathway as well as activation of the p38 and JNK pathways.

Inhibition of melanogenesis by gallic acid: possible involvement of the PI3K/Akt, MEK/ERK and Wnt/ß-catenin signaling pathways in B16F10 cells.

Gallic acid is one of the major flavonoids found in plants. It acts as an antioxidant, and seems to have anti-inflammatory, anti-viral, and anti-cancer properties. In this study, we investigated the effects of gallic acid on melanogenesis, including the activation of melanogenesis signaling pathways. Gallic acid significantly inhibited both melanin synthesis and tyrosinase activity in a dose- and time-dependent manner, and decreased the expression of melanogenesis-related proteins, such as microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and dopachrome tautomerase (Dct). In addition, gallic acid also acts by phosphorylating and activating melanogenesis inhibitory proteins such as Akt and mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK). Using inhibitors against PI3K/Akt (LY294002) or MEK/ERK-specific (PD98059), the hypopigmentation effect was suppressed, and the gallic acid-initiated activation of MEK/ERK and PI3K/Akt was also revoked. Gallic acid also increased GSK3ß and p-ß-catenin expression but down-regulated p-GSK3ß. Moreover, GSK3ß-specific inhibitor (SB216763) restored gallic acid-induced melanin reduction. These results suggest that activation of the MEK/ERK, PI3K/Akt, and inhibition of Wnt/ß-catenin signaling pathways is involved in the melanogenesis signaling cascade, and that activation by gallic acid reduces melanin synthesis via down-regulation of MITF and its downstream signaling pathway. In conclusion, gallic acid may be a potentially agent for the treatment of certain skin conditions.

Sinulariolide induced hepatocellular carcinoma apoptosis through activation of mitochondrial-related apoptotic and PERK/eIF2α/ATF4/CHOP pathway.

Sinulariolide, an active compound isolated from the cultured soft coral Sinularia flexibilis, has potent anti-microbial and anti-tumorigenesis effects towards melanoma and bladder cancer cells. In this study, we investigated the effects of sinulariolide on hepatocellular carcinoma (HCC) cell growth and protein expression. Sinulariolide suppressed the proliferation and colony formation of HCC HA22T cells in a dose-dependent manner and induced both early and late apoptosis according to flow cytometry, Annexin V/PI stain and TUNEL/DAPI stain analyses. A mechanistic analysis demonstrated that sinulariolide-induced apoptosis was activated through a mitochondria-related pathway, showing up-regulation of Bax, Bad and AIF, and down- regulation of Bcl-2, Bcl-xL, MCl-1 and p-Bad. Sinulariolide treatment led to loss of the mitochondrial membrane potential, release of mitochondrial cytochrome c to the cytosol, and activation of both caspase-9 and caspase-3. Sinulariolide-induced apoptosis was significantly blocked by the caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK. The increased expression of cleaved PARP also suggested that caspase-independent apoptotic pathway was involved. In the western blotting; the elevation of ER chaperones GRP78; GRP94; and CALR; as well as up-regulations of PERK/eIF2α/ATF4/CHOP; and diminished cell death with pre-treatment of eIF2α phosphatase inhibitor; salubrinal; implicated the involvement of ER stress-mediated PERK/eIF2α/ATF4/CHOP apoptotic pathway following sinulariolide treatment in hepatoma cells. The current study suggested sinulariolide-induced hepatoma cell cytotoxicity involved multiple apoptotic signal pathways. This may implicate that sinulariolide is a potential compound for the treatment of hepatocellular carcinoma.

Proteomic investigation of the sinulariolide-treated melanoma cells A375: effects on the cell apoptosis through mitochondrial-related pathway and activation of caspase cascade.

Sinulariolide is an active compound isolated from the cultured soft coral Sinularia flexibilis. In this study, we investigated the effects of sinulariolide on A375 melanoma cell growth and protein expression. Sinulariolide suppressed the proliferation and migration of melanoma cells in a concentration-dependent manner and was found to induce both early and late apoptosis by flow cytometric analysis. Comparative proteomic analysis was conducted to investigate the effects of sinulariolide at the molecular level by comparison between the protein profiles of melanoma cells treated with sinulariolide and those without treatment. Two-dimensional gel electrophoresis (2-DE) master maps of control and treated A375 cells were generated by analysis with PDQuest software. Comparison between these maps showed up- and downregulation of 21 proteins, seven of which were upregulated and 14 were downregulated. The proteomics studies described here identify some proteins that are involved in mitochondrial dysfunction and apoptosis-associated proteins, including heat shock protein 60, heat shock protein beta-1, ubiquinol cytochrome c reductase complex core protein 1, isocitrate dehydrogenase (NAD) subunit alpha (down-regulated), and prohibitin (up-regulated), in A375 melanoma cells exposed to sinulariolide. Sinulariolide-induced apoptosis is relevant to mitochondrial-mediated apoptosis via caspase-dependent pathways, elucidated by the loss of mitochondrial membrane potential, release of cytochrome c, and activation of Bax, Bad and caspase-3/-9, as well as suppression of p-Bad, Bcl-xL and Bcl-2. Taken together, our results show that sinulariolide-induced apoptosis might be related to activation of the caspase cascade and mitochondria dysfunction pathways. Our results suggest that sinulariolide merits further evaluation as a chemotherapeutic agent for human melanoma.