Tanshinone I Stimulates Pyroptosis of Cisplatin-Resistant Gastric Cancer Cells by Activating the NF-κB/Caspase-3(8)/GSDME Signaling Pathway.

Cisplatin (DDP) resistance frequently occurs in gastric cancer (GC) therapy. Tanshinone I is a liposoluble phenanthraquinone compound present in the roots of Salvia miltiorrhiza Bunge (Danshen). In this study, we aimed to explore the effects of tanshinone I on modulating DDP resistance of GC cells in vitro and in vivo. DDP-resistant GC cell models (BGC823/DDP and SGC7901/DDP) were established, and their viability, proliferation, migration, lactate dehydrogenase activity, reactive oxygen species (ROS) generation, and pyroptosis were assessed after DDP treatment with or without tanshinone I. In addition, a mouse model with subcutaneously transplanted GC tumors was established to confirm the effects of tanshinone I and DDP on tumor growth and cell pyroptosis. The results revealed that tanshinone I inhibited DDP-resistant GC cell proliferation and migration; increased intracellular ROS levels; and activated cell pyroptosis by enhancing the levels of cleaved caspase-8, cleaved caspase-3, GSDME-NT, phospho-IKK-α/ß, and nuclear factor kappa-B (NF-κB). GSDME knockdown weakened these effects of tanshinone I on DDP-resistant GC cells. Furthermore, DDP combined with tanshinone I inhibited the growth of subcutaneously transplanted GC tumors in mice by reducing cell proliferation and inducing pyroptosis. In conclusion, tanshinone I reversed DDP resistance of GC cells by stimulating pyroptosis, by activating NF-κB/caspase-3(8)/GSDME signaling pathway.

Quinone Pool, a Key Target of Plant Flavonoids Inhibiting Gram-Positive Bacteria.

Plant flavonoids have attracted increasing attention as new antimicrobial agents or adjuvants. In our previous work, it was confirmed that the cell membrane is the major site of plant flavonoids acting on the Gram-positive bacteria, which likely involves the inhibition of the respiratory chain. Inspired by the similar structural and antioxidant characters of plant flavonoids to hydro-menaquinone (MKH2), we deduced that the quinone pool is probably a key target of plant flavonoids inhibiting Gram-positive bacteria. To verify this, twelve plant flavonoids with six structural subtypes were preliminarily selected, and their minimum inhibitory concentrations (MICs) against Gram-positive bacteria were predicted from the antimicrobial quantitative relationship of plant flavonoids to Gram-positive bacteria. The results showed they have different antimicrobial activities. After their MICs against Staphylococcus aureus were determined using the broth microdilution method, nine compounds with MICs ranging from 2 to 4096 µg/mL or more than 1024 µg/mL were eventually selected, and then their MICs against S. aureus were determined interfered with different concentrations of menaquinone-4 (MK-4) and the MKs extracted from S. aureus. The results showed that the greater the antibacterial activities of plant flavonoids were, the more greatly their antibacterial activities decreased along with the increase in the interfering concentrations of MK-4 (from 2 to 256 µg/mL) and the MK extract (from 4 to 512 µg/mL), while those with the MICs equal to or more than 512 µg/mL decreased a little or remained unchanged. In particular, under the interference of MK-4 (256 µg/mL) and the MK extract (512 µg/mL), the MICs of α-mangostin, a compound with the greatest inhibitory activity to S. aureus out of these twelve plant flavonoids, increased by 16 times and 8 to 16 times, respectively. Based on the above, it was proposed that the quinone pool is a key target of plant flavonoids inhibiting Gram-positive bacteria, and which likely involves multiple mechanisms including some enzyme and non-enzyme inhibitions.

Stachydrine, a Bioactive Equilibrist for Synephrine, Identified from Four Citrus Chinese Herbs.

Four Chinese herbs from the Citrus genus, namely Aurantii Fructus Immaturus (Zhishi), Aurantii Fructus (Zhiqiao), Citri Reticulatae Pericarpium Viride (Qingpi) and Citri Reticulatae Pericarpium (Chenpi), are widely used for treating various cardiovascular and gastrointestinal diseases. Many ingredients have already been identified from these herbs, and their various bioactivities provide some interpretations for the pharmacological functions of these herbs. However, the complex functions of these herbs imply undisclosed cholinergic activity. To discover some ingredients with cholinergic activity and further clarify possible reasons for the complex pharmacological functions presented by these herbs, depending on the extended structure-activity relationships of cholinergic and anti-cholinergic agents, a simple method was established here for quickly discovering possible choline analogs using a specific TLC method, and then stachydrine and choline were first identified from these Citrus herb decoctions based on their NMR and HRMS data. After this, two TLC scanning (TLCS) methods were first established for the quantitative analyses of stachydrine and choline, and the contents of the two ingredients and synephrine in 39 samples were determined using the valid TLCS and HPLC methods, respectively. The results showed that the contents of stachydrine (3.04‱) were 2.4 times greater than those of synephrine (1.25‱) in Zhiqiao and about one-third to two-thirds of those of Zhishi, Qingpi and Chenpi. Simultaneously, the contents of stachydrine, choline and synephrine in these herbs present similar decreasing trends with the delay of harvest time; e.g., those of stachydrine decrease from 5.16‱ (Zhishi) to 3.04‱ (Zhike) and from 1.98‱ (Qingpi) to 1.68‱ (Chenpi). Differently, the contents of synephrine decrease the fastest, while those of stachydrine decrease the slowest. Based on these results, compared with the pharmacological activities and pharmacokinetics reported for stachydrine and synephrine, it is indicated that stachydrine can be considered as a bioactive equilibrist for synephrine, especially in the cardio-cerebrovascular protection from these citrus herbs. Additionally, the results confirmed that stachydrine plays an important role in the pharmacological functions of these citrus herbs, especially in dual-directionally regulating the uterus, and in various beneficial effects on the cardio-cerebrovascular system, kidneys and liver.

Circ_0000190 suppresses gastric cancer progression potentially via inhibiting miR-1252/PAK3 pathway.

BACKGROUND: Gastric cancer is a serious malignant tumor associated with aberrant circular RNAs (circRNAs) expression. In this study, we aim to investigate the role and the underlying mechanism of circ_0000190, a circRNA in gastric cancer. METHODS: Circ_0000190 expression in vivo was examined in gastric cancer and adjacent normal tissues by RT-PCR. Circ_0000190 expression in gastric cancer cell lines was detected by FISH and RT-PCR. The role of the circRNA in gastric cancer cells was assessed by the analysis of cell viability, apoptosis, proliferation, cell cycle and migration. The potential effector of circ_0000190 was predicted by computational screen and validated by luciferase reporter assay. Furthermore, Mice model of human gastric cancer was established to observe the underlying mechanisms of circ_0000190. RESULTS: Circ_0000190 was down-regulated in gastric cancer tissues and cells, with a major location in cytoplasm. Circ_0000190 inhibited gastric cancer cell viability, proliferation and migration, and induced apoptosis and cell cycle arrest by regulating the expression of capase-3, p27 and cyclin D. In addition, the circRNA was validated as a sponge of miR-1252, which directly targeted PAK3. The effects of circ_0000190 on the cellular processes were blocked by miR-1252 mimics, which could be rescued after further overexpression of PAK3. CONCLUSIONS: Circ_0000190 suppresses gastric cancer progression potentially via inhibiting miR-1252/PAK3 pathway, employing circ_0000190 might be a promising therapeutic strategy for the treatment of gastric cancer.

BIX-01294 enhanced chemotherapy effect in gastric cancer by inducing GSDME-mediated pyroptosis.

Adjuvant chemotherapy in combination with surgery is expected to be a curative strategy for gastric cancer. However, drug resistance remains an obstacle in effective chemotherapy. Therefore, understanding the potential mechanisms of chemotherapy induced gastric cancer cell death is of great importance. We demonstrated that BIX-01294 (BIX) at low concentration could induce autophagic flux by converting LC3B-I to LC3B-II and directly activate autophagy associated cell death in gastric cancer cell lines at high concentration. BIX at low concentration could help obtain sensitivity of gastric cancer cells to chemotherapy with significantly reduced cell viability. Interestingly, BIX combined Cis (BIX + Cis) treated SGC-7901 cells display pyroptosis related cell death with large bubbles blown around the membrane, significantly decreased cell viability, elevated lactate dehydrogenase release and increased percentage of propidium iodide and Annexin-V double positive cells. Furthermore, the cleavage of gasdermin E (GSDME) and caspase-3 but not GSDMD was detected by immunoblotting and the knockout of GSDME switched pyroptosis into apoptosis in the BIX + Cis combined treated group. Furthermore, the deficiency of Beclin-1 to inhibit BIX induced autophagic flux completely blocked BIX + Cis combined treated induced cell pyroptosis related cell death. Additionally, BIX + Cis in vivo treatment could inhibit tumor growth, which could be reversed by the deficiency of Beclin-1 and be delayed by the deficiency of GSDME. In conclusion, our data was the first to reveal that BIX enhanced the anticancer chemotherapy effect by induced GSDME-mediated pyroptosis through the activation of autophagic flux in gastric cancer cells.

Reactivation of microRNA-506 inhibits gastric carcinoma cell metastasis through ZEB2.

MicroRNAs (miRNAs) are frequently dysregulated in a variety of human cancers, including gastric carcinoma. To improve our understanding of the role of miRNAs in gastric carcinoma and potential identify novel biomarkers or therapeutic agents, we performed microarray analysis to identify differentially expressed miRNAs in gastric carcinoma, compared with paired non-cancerous gastric tissues. We identified significantly differentially expressed miRNAs in gastric carcinoma tissues, including miR-506. We validated the microarray results by quantitative reverse transcription polymerase chain reaction in 26 specimens and confirmed significant downregulation of miR-506 in gastric carcinoma. Bioinformatics analysis predicted ZEB2 (zinc finger E-box-binding homeobox 2) as a potential target of miR-506. MiR-506 levels and ZEB2 levels were inversely correlated in gastric carcinoma, and low miR-506 levels in gastric carcinoma were associated with poor prognosis. Overexpression of miR-506 in gastric carcinoma cells significantly inhibited cell migration and invasion, while depletion of miR-506 in gastric carcinoma cells significantly increased cell migration and invasion. Transplantation of miR-506-overexpressing gastric carcinoma cells developed significantly smaller tumor, compared to the control. Thus, our results suggest that miR-506 may function as a tumor suppressor and targets and inhibits ZEB2 in gastric carcinoma.

Single Fluorescent Probe Separately and Continuously Visualize H2S and HClO in Lysosomes with Different Fluorescence Signals.

A complicated relationship between the active small molecules exists in cells. On the organelle level, active small molecules also play an important role in the maintenance of organelle functions and roles. To investigate the relationship of biomolecules in subcellular, it is necessary and critical to develop molecular tools that can track two kinds of associated biomolecules within organelles with multiple fluorescence signals. However, this is still an unmet challenge up to date. Herein, we present the first single-fluorescent probe (Lyso-HA-HS) that can detect oxidative (HOCl) and reductive (H2S) substances within an organelle (lysosomes) with multiresponse signals. The reactions of the new probe with H2S and HOCl simultaneously result in the blue and red channels emissions, respectively, providing different signal responses to the oxidative and reductive substances in the cellular lysosomes. Using a single fluorescent probe, we first achieved dual-channel imaging of the endogenous hypochlorous acid and hydrogen sulfide, respectively, in the lysosomes in the living cells. Moreover, the highly desirable attributes of the probe Lyso-HA-HS (such as high selectivity, good membrane-permeability, and lysosome enrichment ability) may enable it to be used in revealing the relationship of HOCl and H2S in lysosomes.

Preparation of a Two-Photon Fluorescent Probe for Imaging H2O2 in Lysosomes in Living Cells and Tissues.

Hydrogen peroxide (H2O2) plays important roles in many physiological and pathological processes. At the cellular organelle level, the abnormal concentrations of H2O2 in the lysosomes may cause redox imbalance and the loss of the critical functions of the lysosomes. Herein, we describe the preparation of a potent lysosome-targeted two-photon fluorescent probe (Lyso-HP) for the detection of H2O2 in the lysosomes in the living cells. This unique fluorescent probe can also be employed to effectively detect H2O2 in the living tissues using two-photon fluorescence microscopy.

A targetable fluorescent probe for imaging exogenous and intracellularly formed nitroxyl in mitochondria in living cells.

Nitroxyl plays crucial roles in many biological pathways and can serve as a potent therapeutic agent for the treatment of heart failure. Recent studies suggest that HNO may be produced in mitochondria and the HNO formed might have functional consequences for mitochondrial activity. However, in order to study the function of HNO in mitochondria, a suitable research method is needed. Herein, through rational design, we synthesized a new mitochondria-targeted fluorescent nitroxyl probe (Mito-HNO). The developed probe was highly selective toward HNO over other reactive nitrogen species and reducing species. In addition, the probe Mito-HNO was rapidly responsive and suitable for visualization of HNO in mitochondria in living cells. The probe is expected to be employed in further revealing the biological function of HNO in subcellular mitochondria.

Single Fluorescent Probe for Dual-Imaging Viscosity and H2O2 in Mitochondria with Different Fluorescence Signals in Living Cells.

Mitochondria, as essential and interesting organelles within the eukaryotic cells, play key roles in a variety of pathologies, and its abnormalities are closely associated with Alzheimer's disease (AD) and other diseases. Studies have shown that the abnormal of viscosity and concentration of hydrogen peroxide in mitochondria were all associated with AD. Accordingly, the detection of viscosity and hydrogen peroxide in mitochondria has attracted great attention. However, it remains a great challenge to explore a single probe, which can dual-detect the viscosity and H2O2 in mitochondria. Herein, in two ways to prevent the twisted internal charge transfer (TICT) process, we designed and sythesized the first dual-detection fluorescent probe Mito-VH that can visualize viscosity and H2O2 in mitochondria with different fluorescence signals in living cells.

A TICT-based fluorescent probe for rapid and specific detection of hydrogen sulfide and its bio-imaging applications.

By blocking the intramolecular twisted internal charge transfer (TICT) process, we designed and sythesized the first TICT-based fluorescent probe for hydrogen sulfide. The new probe exhibits high selectivity, good membrane-permeability and is suitable for visualization of exogenous and endogenous hydrogen sulfide in living cells.

A fast responsive two-photon fluorescent probe for imaging H2O2 in lysosomes with a large turn-on fluorescence signal.

Hydrogen peroxide (H2O2) plays a crucial role in many biological processes in the human body. As our understanding of the complexity of physiological H2O2 in lysosome, investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed a new example of a fast responsive and lysosome-targeted two-photon H2O2 fluorescent probe (Lyso-HP) with a large turn-on fluorescence signal (80-fold fluorescence enhancement). The addition of H2O2 to Lyso-HP results a dramatic fluorescence enhancement around 550 nm. The probe could image exogenous and endogenous H2O2 in living cells and the probe was located in lysosomes with high colocalization coefficient (0.96) compared with LysoTracker. The large fluorescence enhancement of the two-photon probe Lyso-HP renders it attractive for imaging H2O2 in living tissues with deep tissue penetration. Significantly, the probe is feasible for fluorescently monitoring H2O2 level changes in lysosomes and suitable for fluorescence imaging of H2O2 in living tissues with deep penetration by using two-photon microscopy.

A lysosome-targeted and ratiometric fluorescent probe for imaging exogenous and endogenous hypochlorous acid in living cells.

Hypochorous acid plays important roles in numerous physiological and pathological processes. At the cell organelle level, an abnormal concentration of hypochorous acid in the lysosomes causes redox imbalance and the loss of function of the lysosomes. Herein, the first small molecule based, lysosomal-targeted ratiometric fluorescent HOCl probe (Lyso-HA) was synthesized through a rational design. The new probe was highly selective toward HOCl over other reactive oxygen species and exhibits a large variation (up to 97-fold) in its fluorescence ratio (I585/I450), with good signal resolution. The probe Lyso-HA is membrane-permeable and is suitable for ratiometric visualization of exogenous and endogenous HOCl at lysosomes in living cells.

A dual-emission fluorescence-enhanced probe for imaging copper(ii) ions in lysosomes.

We have developed the first example of a fluorescence-enhanced and lysosome-targeted Cu2+ probe (Lys-Cu) with unique dual-channel emissions. The newly synthesized fluorescent probe Lys-Cu, which contains two recognition sites with different sensing mechanisms for Cu2+, displays fluorescence-enhanced dual-channel emissions with fluorescence response to Cu2+ in the lysosome pH environment. Fluorescence imaging shows that Lys-Cu is membrane-permeable and suitable for visualization of Cu2+ in lysosomes of living cells by dual-channel imaging.

Expression of tissue factor pathway inhibitor-2 in gastric stromal tumor and its clinical significance.

The aim of this study was to explore the expression of tissue factor pathway inhibitor-2 (TFPI-2) in gastric stromal tissue and its clinical significance. TFPI-2 expression was detected by immunohistochemical analysis, RT-PCR and western blotting in tumor, peritumoral and gastric normal tissues from 72 patients with gastric stromal tumors. The level of TFPI-2 expression was observed to be significantly higher in gastric normal tissue than in peritumoral tissue, and was significantly higher in peritumoral tissue than in tumor tissue (P<0.01). As the NIH grade increased, the level of TFPI-2 expression decreased (P<0.01). A low expression level of TFPI-2 was closely associated with invasion and metastasis of gastric stromal tumors. In conclusion, the level of TFPI-2 expression was higher in gastric normal tissue than in gastric stromal tumors. Low expression levels of TFPI-2 may be associated with invasion and metastasis of gastric stromal tumors.

Expression of protease-activated receptor-2 in human gastric stromal tumor and its clinicopathological significance.

BACKGROUND/AIMS: To explore the expression of protein-activated receptor-2 (PAR-2) in human gastric stromal tumor and its clinicopathological significance. METHODOLOGY: The expression of PAR-2 was detected with immunohistochemisty, RT-PCR and Western blot in tumor tissue, peritumoral tissue and gastric normal tissue from 72 patients with gastric stromal tumor. RESULTS: PAR-2 expression was significantly higher in peritumoral tissue (p < 0.05) and tumor tissue (p < 0.01) than in gastric normal tissue, and significantly higher in tumor tissue than in peritumoral tissue (p < 0.01). With the increase in NIH grade, PAR-2 expression was elevated in tumor tissues. PAR-2 expression was strongly associated with mucosal invasion. CONCLUSIONS: PAR-2 expression is significantly higher in gastric stromal tumor tissue than in peritumoral tissue and gastric normal tissue. The high expression of PAR-2 may be associated with the invasion and metastasis of gastric stromal tumor.