A Mechanism for Apoptotic Effects of a Planar Catechin Analog on Cancer Cells.

Catechin is one of the representative antioxidants that shows physiological activities such as an anti-cancer effect. We have developed a chemically modified catechin analog possessing a planar structure, which shows an enhanced radical-scavenging activity as well as inhibitory effects on the proliferation and migration of cancer cells, compared to the parent (+)-catechin. In this study, the mechanism for cancer cell inhibition by the planar catechin was partly elucidated using a gastric cancer cell line. The planar catechin treatment induced an enhanced expression of an apoptotic marker, cleaved caspase-3, in addition to the mitigation of the intracellular accumulation of reactive oxygen species (ROS) and NF-κB expression. Furthermore, γH2AX, a marker of double-strand breaks in DNA, was also induced by the planar catechin treatment in a dose-dependent manner. These findings suggest that the removal of ROS by the planar catechin with a higher antioxidant ability executed NF-κB suppression and/or the planar catechin-injured DNA, leading to the induction of apoptosis in cancer cells.

Inhibitory Effects of Royal Jelly and Its Functional Components on the Proliferation of MKN-28 Gastric Cancer Cells.

Royal jelly (RJ) is a natural food product with nutritional value and anticancer activity. However, their effects on gastric cancer are unclear. Here, we show that treatment with 5-320 µg/mL of RJ, ethanol extract (RJEE), and protein hydrolyzate (RJPH) decreased the viability of MKN-28 gastric cancer cells, with a half-maximal inhibitory concentration of 123.22 µg/mL for RJEE. RJ, RJEE, and RJPH increase the lactate dehydrogenase release rate and change the morphology of the cells, resulting in cell shrinkage, nucleoplasm condensation, and the formation of apoptotic bodies. RJ and its functional components stagnated the cell cycle in the G0/G1 phase, accompanied by the accumulation of reactive oxygen species, decreased mitochondrial membrane potential, and increased expression levels of p53 and p21 proteins, caspase-3 activation, and apoptosis. Therefore, RJ, RJEE, and RJPH have potential inhibitory effects on the proliferation of gastric cancer cells.

Cytotoxic effects of NIR responsive chitosan-polymersome layer coated melatonin-upconversion nanoparticles on HGC27 and AGS gastric cancer cells: Role of the ROS/PI3K/Akt/mTOR signaling pathway.

In this study, a formulation of NaGdF4:Tm/Er@NaGdF4 (core@shell) UCNPs loaded with melatonin drug was synthesized. The novel melatonin-loaded UCNPs were then encapsulated within NIR-responsive biopolymeric chitosan (CS) based polymersome and investigated against gastric cancer (HGC27 & AGS) cells. The photolysis of the ONB moiety and disruption of the disulfide linkage in the polymersome induced by NIR light facilitated by the NaGdF4:Tm/Er@NaGdF4 UCNPs and GSH results in an increased release of melatonin drug. The DLS and zeta potential measurements exhibit a reduced particle size (21.9 ± 3.56 nm) and a low zeta potential (17.91 mV). Furthermore, drug release profiles demonstrated superior melatonin drug release (79.78 %) at pH 5.0 for CS-polymersome-coated melatonin-UCNPs resembling the Hixson-Crowell model. Remarkably, CS-polymersome-coated melatonin-UCNPs exhibit excellent anti-proliferative properties for HGC27 (IC50 = 0.096 µM) and AGS (IC50 = 0.16 µM) cancer cells. The flow cytometry data demonstrate a significant elevation in ROS levels which promoted cell death in both HGC-27 and AGS cells. The observed cell mortality in HGC-27 and AGS cells is primarily caused by the destruction of the nucleus, mtDNA, rupture of disulfide (R-S-S-R) bonds, and nuclear DNA. Contrarily, L929 and HUVECs cells incubated with CS-polymersome coated melatonin-UCNPs (100 µg/mL) reveal a notable cell viability of 88.7 % and 93 % indicating superior biocompatibility. The western blotting analysis revealed the induction of autophagy by CS-polymersome-coated melatonin-UCNPs which subsequently led to apoptosis by regulating the ROS/PI3K/Akt/mTOR molecular signaling pathway.

Effects of catechin on the malignant biological behavior of gastric cancer cells through the PI3K/Akt signaling pathway.

Catechin is a kind of flavonoids, mainly derived from the plant Camellia sinensis. It has a strong antioxidant effect, and it also has significant therapeutic effects on anti-cancer, anti-diabetes, and anti-infection. This study was intended to look at how catechin affected the malignant biological activity of gastric cancer cells. We used databases to predict the targets of catechin and the pathogenic targets of gastric cancer. Venn diagram was used to find the intersection genes, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses were performed on intersection genes. Using the STRING database, the Protein-Protein Interaction (PPI) network was built. The top 8 genes were screened by Cytoscape 3.9.1, then their binding was verified by molecular docking. The proliferation ability, cell cycle, apoptosis and migration of gastric cancer cells were detected, as well as the protein expression levels of PI3K, p-AKT, and AKT and the mRNA expression levels of AKT1, VEGFA, EGFR, HRAS, and HSP90AA1 in gastric cancer cells. Our research revealed that different concentrations of catechin could effectively inhibit the proliferation and migration of gastric cancer cells, regulate the cell cycle, and promote the death of these cells, and it's possible that the PI3K/Akt pathway was crucial in mediating this impact. Moreover, adding the PI3K/Akt pathway agonist significantly reduced the promoting effect of catechin on the apoptosis of gastric cancer cells. This study suggested that catechin was a potential drug for the treatment of gastric cancer.

Methionine restriction attenuates the migration and invasion of gastric cancer cells by inhibiting nuclear p65 translocation through TRIM47.

The prevention and treatment of gastric cancer has been the focus and difficulty of medical research. We aimed to explore the mechanism of inhibiting migration and invasion of gastric cancer cells by methionine restriction (MR). The human gastric cancer cell lines AGS and MKN45 cultured with complete medium (CM) or medium without methionine were used for in vitro experiments. MKN45 cells were injected tail vein into BALB/c nude mice and then fed with normal diet or methionine diet for in vivo experiments. MR treatment decreased cell migration and invasion, increased E-cadherin expression, decreased N-cadherin and p-p65 expressions, and inhibited nuclear p65 translocation of AGS and MKN45 cells when compared with CM group. MR treatment increased IκBα protein expression and protein stability, and decreased IκBα protein ubiquitination level and TRIM47 expression. TRIM47 interacted with IκBα protein, and overexpression of TRIM47 reversed the regulatory effects of MR. TRIM47 promoted lung metastasis formation and partially attenuated the effect of MR on metastasis formation in vivo compared to normal diet group mice. MR reduces TRIM47 expression, leads to the degradation of IκBα, and then inhibits the translocation of nuclear p65 and the migration and invasion of gastric cancer cells.

Investigating the role of LncRNA PSMG3-AS1 in gastric cancer: implications for prognosis and therapeutic intervention.

LncRNAs are widely linked to the complex development of gastric cancer, which is acknowledged worldwide as the third highest contributor to cancer-related deaths and the fifth most common form of cancer. The primary focus of this study is to examine the role of LncRNA PSMG3-AS1 in a group of individuals with gastric cancer. The results of our study indicate that PSMG3-AS1 is highly expressed in over 20 different types of cancer. Significantly, there was a clear association found between the expression of PSMG3-AS1 and a multitude of TMB and MSI tumors. PSMG3-AS1 exhibited significant upregulation in gastric cancer patients compared to healthy individuals within the gastric cancer cohort. The prognosis of gastric cancer patients is intrinsically associated with PSMG3-AS1, as confirmed by survival analysis and ROC curves. Furthermore, we created a disruption vector based on LncRNA PSMG3-AS1 and introduced it into AGS and MKN-45 cells, which are human gastric cancer cells. Significant decreases in the expression of the PSMG3-AS1 gene were noticed in both intervention groups compared to the NC group, reflecting the protein level expressions. Significantly, the proliferative and invasive capabilities of MKN-45 and AGS cells were notably reduced following transfection with PSMG3-AS1 siRNA. The results of our study indicate that disruption of the LncRNA PSMG3-AS1 gene may impact the CAV1/miR-451a signaling pathway, thereby leading to a reduction in the ability of gastric cancer cells to multiply and invade.

[Corrigendum] Crocetin induces apoptosis of BGC­823 human gastric cancer cells.

Following the publication of the above article, an interested reader drew to the authors' attention that Fig. 2 (showing morphological characteristics of cultured BGC­823 cells as visualized by microscopic analysis) and Fig. 3 (showing crocetin­induced apoptosis of the BGC­823 cells) on p. 523 appeared to feature panels containing overlapping data. The authors re­examined their original data, and realized that inadvertent errors were made during the compilation of these figures; specifically, the data shown in Fig. 2C (for the the 5­µM docetaxel group) and Fig. 3D (for the DMSO group) were selected incorrectly. The corrected versions of Figs. 2 and 3 are shown below and on the next page, now featuring the correct data for Figs. 2C and 3D. All the authors agree with the publication of this corrigendum, and are grateful of the Editor of Molecular Medicine Reports for granting them the opportunity to publish this. Furthermore, they regret that these errors were introduced into the paper, even though they did not substantially alter any of the major conclusions reported in the paper, and apologize to the readership for any inconvenience caused. [Molecular Medicine Reports 9: 521­526, 2014; DOI: 10.3892/mmr.2013.1851].

Anti-cancer activity of green synthesized silver nanoparticles using Ardisia gigantifolia leaf extract against gastric cancer cells.

Using extracts from herbs for silver nanoparticle synthesis is attracting attention for its anticancer activity. Ardisia gigantifolia is a herb used in traditional Chinese medicine for treating stomach ailments, and some compounds isolated from this plant exhibit the inhibitory activity against different cancer cells. However, the synthesis of silver nanoparticle using extract of Ardisia gigantiflia leaves and their anti-cancer activity was not reported. In this report, the green synthesized silver nanoparticles using Ardisia gigantiflia extract (Arg-AgNPs) has average diameter of 6 nm with functional groups including O-H, C-H, and CO founded on the surface of these nanoparticles. The viability assays results revealed Arg-AgNPs reduced gastric cancer cell proliferation in a dose-dependent manner, with IC50 values of 1.37 and 0.65 µg/mL for AGS cells and 1.03 and 0.96 µg/mL for MKN45 cells. Arg-AgNPs caused cell cycle arrest at the G0/G1 phase and suppressed cell migration. Additionally, Arg-AgNPs significantly increased the percentage of senescent cells and promoted overproduction of reactive oxygen species (ROS) compared to the control. Thus, this study indicates that Arg-AgNPs can be considered as a promising candidate against human gastric cancer cells.

Novel Property Cytotoxicity and Mechanism of Food Preservative Brevilaterins against Human Gastric Cancer Cells.

Brevilaterins, antimicrobial peptides produced by Brevibacillus laterosporus, are regarded as excellent food preservatives and are popular as antimicrobial applications. Recent research has uncovered their potent cytotoxic effects against diverse cancer cells, thereby underscoring the pressing need for more extensive and intensive investigations into this use. In this study, we explored their novel function in inducing cytotoxicity to cancer cells and systematically investigated the mechanism of action of Brevilaterin B/C (BB/BC) in vivo. Proliferation, membrane permeability, and apoptotic rate were evaluated using CCK-8 assay, LDH assay, and Annexin V-FITC/PI kits. ROS levels and mitochondrial membrane potential were detected using the fluorescent probe DCFH-DA and JC-1. Our results demonstrated that both BB and BC at concentrations of 4-6 µg/mL significantly inhibited the proliferation and migration of gastric cancer cells BGC-823. Treatment with 4 µg/mL of BB/BC rapidly increased LDH levels in the supernatant of BGC-823 cells, leading to further investigation of the mechanism of apoptosis. We found that the apoptotic rate of BGC-823 cells significantly increased upon treatment with BB/BC, demonstrating their potent induction of apoptosis. BB/BC-induced ROS production in BGC-823 cells impaired their growth and induced apoptosis, indicating a close association between apoptosis and ROS elevation. Additionally, JC-1 aggregates rapidly accumulated after treatment with 4 µg/mL of BB/BC, suggesting changes in mitochondrial membrane potential and early apoptosis. Taken together, our findings revealed that BB and BC exhibit significant anticancer effects against gastric cancer cells, highlighting the promising potential of Brevilaterins as anticancer agents.

FOXO signaling pathway participates in oxidative stress-induced histone deacetylation.

High concentrations of antioxidants can exert pro-oxidative effects, elevate the level of intracellular reactive oxygen species (ROS), and cause oxidative stress in cells. We previously found that high concentrations of curcumin, a natural polyphenol antioxidant, elevated ROS levels and upregulated the expression of histone deacetylase 1 (HDAC1) in human gastric cancer cells (hGCCs); however, its potential mechanisms and subsequent functions have not been elucidated. In the present study, we treated hGCCs with high concentrations of curcumin, detected several indicators of oxidative stress, and investigated the mechanism of curcumin-treatment-mediated HDAC1 upregulation and its effect on histone acetylation. The results showed that curcumin treatment caused oxidative stress in hGCCs and upregulated HDAC1/2 expression via the forkhead box O (FOXO) signaling pathway, ultimately leading to the deacetylation of histones in hGCCs. Moreover, HDAC1/2 mediates the deacetylation of FOXOs and promotes their transcription activities, implying a positive feedback loop between FOXOs and HDAC1/2. These findings present a mechanism by which oxidative stress induces histone deacetylation in hGCCs.

Lutein Induces Reactive Oxygen Species-Mediated Apoptosis in Gastric Cancer AGS Cells via NADPH Oxidase Activation.

Disruption of apoptosis leads to cancer cell progression; thus, anticancer agents target apoptosis of cancer cells. Reactive oxygen species (ROS) induce apoptosis by activating caspases and caspase-dependent DNase, leading to DNA fragmentation. ROS increase the expression of apoptotic protein Bax, which is mediated by activation of nuclear factor-κB (NF--κB). Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an important source of endogenous ROS, and its activation is involved in apoptosis. Lutein, an oxygenated carotenoid and known antioxidant, is abundant in leafy dark green vegetables, such as spinach and kale, and in yellow-colored foods, such as corn and egg yolk. High amounts of lutein increase ROS levels and exhibit anticancer activity. However, its anticancer mechanism remains unclear. This study aimed to determine whether lutein activates NADPH oxidase to produce ROS and induce apoptosis in gastric cancer AGS cells. Lutein increased ROS levels and promoted the activation of NADPH oxidase by increasing the translocation of NADPH oxidase subunit p47 phox to the cell membrane. It increased NF-κB activation and apoptotic indices, such as Bax, caspase-3 cleavage, and DNA fragmentation, and decreased Bcl-2, cell viability, and colony formation in AGS cells. The specific NADPH oxidase inhibitor ML171, and the known antioxidant N-acetyl cysteine reversed lutein-induced cell death, DNA fragmentation, and NF-κB DNA-binding activity in AGS cells. These results suggest that lutein-induced ROS production is dependent on NADPH oxidase, which mediates NF-κB activation and apoptosis in gastric cancer AGS cells. Therefore, lutein supplementation may be beneficial for increasing ROS-mediated apoptosis in gastric cancer cells.

Cyanidin-3-O-Glucoside Induces the Apoptosis of Human Gastric Cancer MKN-45 Cells through ROS-Mediated Signaling Pathways.

Cyanidin-3-O-glucoside (C3G), an active ingredient in anthocyanins, mainly exists in dark cereals. C3G was investigated for its effect on human gastric cancer (GC) cells, together with its molecular mechanism. The CCK-8 assay results showed that C3G had significant antiproliferative effects on GC cells, but it had little effect on normal cells. Western blot and flow cytometry results showed that C3G regulated the reduction of mitochondrial membrane potential and arrested the cell cycle in the G2/M phase through the AKT signaling pathway, causing the cells to undergo apoptosis. Additionally, in MKN-45 cells, C3G markedly raised intracellular reactive oxygen species (ROS) levels. The wound healing assay and Transwell assay results showed that MKN-45 cell migration was significantly inhibited. Western blot results showed that the expression of E-cadherin protein was upregulated and the expressions of ß-catenin, N-cadherin, and Vimentin were downregulated. Additionally, following N-acetylcysteine treatment, the expression levels of these proteins were reduced. In conclusion, C3G caused MKN-45 cells to undergo apoptosis; arrested the cell cycle in the G2/M phase; hindered cell migration; and activated the MAPK, STAT3, and NF-κB signaling pathways, by inducing an increase in ROS levels. Thus, C3G may be a promising new medication for the treatment of GC.

Dual COX-2/5-LOX inhibitors from Zanthoxylum simulans inhibit gastric cancer cells by cross-mediating thyroid, estrogen, and oxytocin signaling pathways.

Cyclooxygenase 2 (COX-2) and 5-lipoxygenase (5-LOX) are overexpressed in gastric cancer cells, the dual inhibitors of which exhibit potential against metastasis and invasion with fewer side effects. To discover inhibitors targeting COX-2 and 5-LOX, we conducted ultrafiltration and enrichment calculation to screen candidates in quaternary alkaloids (QAs) from Zanthoxylum simulans through LC and LC-Q-TOF. For intensive peaks, peaks 19 (berberine) and 21 (chelerythrine) were observed as the most potent dual candidates and showed selective affinity to 5-LOX over COX-2. Peak 19 showed an enrichment at 4.36 for COX-2 and 22.81 for 5-LOX, while peak 21 showed an enrichment at 7.81 for COX-2 and 24.49 for 5-LOX. Molecular docking results revealed chelerythrine as a better dual inhibitor, showing time- and dose-dependent anti-proliferation against AGS cells. Bio-informatics strategies, such as Gene Expression Omnibus (GEO), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG), suggested that hormone pathways in gastric cancer cells might be mediated by chelerythrine. Further reviews and summaries helped outline the mechanisms by which COX-2/5-LOX inhibitors might promote apoptosis in gastric cancer cells via estrogen, thyroid, and oxytocin signaling pathways. Chelerythrine was also added to gastric cancer cells to verify the regulation of these three signaling pathways. As a result, significant calling back of thyroid-stimulating hormone receptor (TSHR), thyroid hormone α3 (TRα3), and thyroid hormone receptor ß1 (TRß1) and suppressing estrogen receptor α36 (ER-α36)-Src could benefit the anti-proliferation of chelerythrine. However, it was disappointing that regulation of estrogen receptor α66 (ER-α66), estrogen receptor ß (ER-ß), and oxytocin receptor (OTR) contributed inversely negative effects on anti-gastric cancer cells. At present, the integrative study not only revealed chelerythrine as the most potent dual COX-2/5-LOX inhibitor from QAs but also generally highlighted that comprehensive regulation of the estrogen, thyroid, and oxytocin pathway should be noted once gastric cancer cells were treated with inflammatory inhibitors.

Induction of Apoptosis and Effect on the FAK/AKT/mTOR Signal Pathway by Evodiamine in Gastric Cancer Cells.

Evodiamine isolated from Evodia rutaecarpa has been known to have anti-tumor activity against various cancer cell types. Although there have been reports showing the inhibitory effect of evodiamine on cell survival of gastric cancer cell, it is not clearly explained how evodiamine affects the expression and modification of proteins associated with apoptosis and upstream signal pathways. We confirmed the cytotoxic activity of evodiamine against AGS and MKN45 cells by a WST assay, cell morphological change, and clonogenic assay. The apoptotic cells were evaluated by Annexin V/PI analysis and Western blot and the expressions of apoptosis-related molecules were confirmed by Western blot. Evodiamine promoted apoptosis of AGS gastric cancer cells through both intrinsic and extrinsic signal pathways in a time- and dose-dependent manner. Evodiamine attenuated the expression of anti-apoptotic proteins, including Bcl-2, XIAP, and survivin, and elevated that of the pro-apoptotic protein Bax. Evodiamine also suppressed the FAK/AKT/mTOR signal pathway. Based on these results, we expect that the results from this study will further elucidate our understanding of evodiamine as an anti-cancer drug.

Laminin 511-E8 Fragment Offers Superior Adhesion Properties for Gastric Cancer Cells Compared with Full-Length Laminin 511.

BACKGROUND: The interaction between cancer cells and laminin (Ln) is a key event in tumor invasion and metastasis. Previously, we determined the effect of full-length Ln511 on gastric cancer cells. However, the interactions between the Ln511-E8 fragment, a truncated protein of Ln511, and gastric cancer cells have not been investigated. METHODS: We investigated the adhesion properties of gastric cancer cells to full-length Ln511 and Ln511-E8 fragments. RESULTS: The proliferation of four gastric cancer cell lines (SH-10-TC, MKN74, SC-6-JCK, and MKN45) was highest on the Ln511-E8 fragment. Further, a larger cytoplasm was observed in SH-10-TC and MKN74 cells cultured on full-length Ln511 or Ln511-E8 fragments. The percentage of adhesive cells was highest on the Ln511-E8 fragment in all four cell lines. Moreover, adhesion of the gastric cancer cells to Ln511-E8 fragment-coated plates was reduced by the Cdc42 GTPase inhibitor in a dose-dependent manner, suggesting the involvement of Cdc42 in the Ln511-E8 fragment-induced enhanced adhesion of gastric cancer cells. CONCLUSIONS: The Ln511-E8 fragment had a greater impact on the adhesion, morphology, and proliferation of gastric cancer cells than full-length laminin. Thus, the Ln511-E8 fragment is suitable for investigating the interaction between gastric cancer cells and extracellular matrices in tumor invasion and metastasis.

Differential Impacts on Tensional Homeostasis of Gastric Cancer Cells Due to Distinct Domain Variants of E-Cadherin.

In epithelia, breakdown of tensional homeostasis is closely associated with E-cadherin dysfunction and disruption of tissue function and integrity. In this study, we investigated the effect of E-cadherin mutations affecting distinct protein domains on tensional homeostasis of gastric cancer cells. We used micropattern traction microscopy to measure temporal fluctuations of cellular traction forces in AGS cells transfected with the wild-type E-cadherin or with variants affecting the extracellular, the juxtamembrane, and the intracellular domains of the protein. We focused on the dynamic aspect of tensional homeostasis, namely the ability of cells to maintain a consistent level of tension, with low temporal variability around a set point. Cells were cultured on hydrogels micropatterned with different extracellular matrix (ECM) proteins to test whether the ECM adhesion impacts cell behavior. A combination of Fibronectin and Vitronectin was used as a substrate that promotes the adhesive ability of E-cadherin dysfunctional cells, whereas Collagen VI was used to test an unfavorable ECM condition. Our results showed that mutations affecting distinct E-cadherin domains influenced differently cell tensional homeostasis, and pinpointed the juxtamembrane and intracellular regions of E-cadherin as the key players in this process. Furthermore, Fibronectin and Vitronectin might modulate cancer cell behavior towards tensional homeostasis.

Bioactivity of Two Polyphenols Quercetin and Fisetin against Human Gastric Adenocarcinoma AGS Cells as Affected by Two Coexisting Proteins.

It is recognized that minor dietary components polyphenols have anticancer effects on digestive tract, lung, leukemia, and other cancers, while polyphenols also can covalently or noncovalently interact with major dietary components proteins such as casein, soybean proteins, whey proteins, and bovine serum albumin. Thus, whether the noncovalent interaction between the molecules of two polyphenols (quercetin and fisetin) and two proteins (bovine serum albumin and casein) has positive or negative impact on anticancer activities of the polyphenols against human gastric adenocarcinoma AGS cells was assessed in this study. The two polyphenols had obvious anticancer activities to the cells, because dose levels as low as 20-160 µmol/L caused reduced cell viability of 30.0-69.4% (quercetin) and 24.6-63.1% (fisetin) (using a cell treatment time of 24 h), or 9.9-48.6% (quercetin) and 6.4-29.9% (fisetin) (using a cell treatment time of 48 h). However, the cell treatments by the polyphenols in the presence of the two proteins mostly caused lower polyphenol activity toward the cells, compared with those treatments by the polyphenols in the absence of the proteins. Specifically, the presence of the proteins led to reduced growth inhibition in the cells, because higher cell viability of 33.2-86.7% (quercetin) and 29.1-77.7% (fisetin) at 24 h, or 14.1-66.8% (quercetin) and 7.9-59.0% (fisetin) at 48 h, were measured in these treated cells. The two coexisting proteins also yielded the polyphenol-treated cells with less mitochondrial membrane potential loss, less formation of reactive oxygen species, and decreased cell apoptosis. Thus, it is highlighted that the noncovalent interaction between dietary polyphenols and proteins resulted in weakened anticancer ability for the polyphenols to the gastric cancer cells.

Synthesis, Characterization and Anticancer Efficacy Evaluation of Benzoxanthone Compounds toward Gastric Cancer SGC-7901.

Three benzoxanthone derivatives were synthesized through a new photochemical strategy. The in vitro cytotoxic activity of these compounds was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and their partition coefficients (logP) were measured by shake flask method. The pKa values of the compounds were detected by potentionmetric titration. The interaction of the compounds with calf thymus DNA (CT-DNA) was investigated by electronic absorption, luminescence spectra and viscosity. A molecular docking analysis was performed. The antitumor efficacy of the compounds was evaluated by cell apoptosis, cell cycle arrest, intracellular Ca2+ concentrations and reactive oxygen species (ROS) levels. The mitochondrial membrane potential was assayed using JC-1 (5,5',6,6'-tetrachloro-1,1,3',3'-tetraethyl-imidacarbocyanine iodide) as the fluorescence probe. The expression of Bcl-2 family protein, caspase 3 and poly ADP-ribose polymerase (PARP) was explored by western blot. The results showed that the compounds induced apoptosis through a ROS-mediated mitochondrial dysfunction pathway. This work provides an efficient approach to synthesize benzoxanthone derivatives, and is helpful for understanding the apoptotic mechanism.

PI3K inhibitor 3-MA promotes the antiproliferative activity of esomeprazole in gastric cancer cells by downregulating EGFR via the PI3K/FOXO3a pathway.

Gastric cancer is a common gastrointestinal malignancy worldwide, with a high mortality rate and poor prognosis. Esomeprazole (ESO) has been shown to have anticancer activity by affecting cell growth and autophagy and its mechanism in gastric cancer cells is evident. The PI3K/AKT/FOXO3a pathway is central in cancers. 3-Methyladenine (3-MA), a dual inhibitor of PI3K and autophagy, plays a synergistic role in combination with antitumor agents. In this study, we assessed the role of ESO on the PI3K/AKT/FOXO3a pathway and the beneficial effects of ESO combined with 3-MA in gastric cancer cells. Cell viability, proliferation, invasion, migration, apoptosis, autophagy, and protein expression were detected by CCK-8, EdU, Transwell, flow cytometry, immunofluorescence assay, and western blot. ESO decreased cell viability in a concentration- and time-dependent manner and increased autophagy with upregulation of LC3II and P62. Additionally, ESO inhibited the proliferation, migration, and invasion and induced the apoptosis of gastric cancer cells in a concentration-dependent manner. ESO inhibited PI3K/AKT/FOXO3a signaling and EGFR and SKP2 expression concentration-dependent. 3-MA enhanced the antiproliferative activity of ESO and synergistically inhibited PI3K/FOXO3a signaling and the expression of EGFR but not SKP2. Furthermore, pretreatment with the EGFR inhibitor AG1478 enhanced the antiproliferative activity of ESO in gastric cancer cells. In conclusion, our results suggested that the PI3K inhibitor 3-MA promotes the antiproliferative activity of ESO in gastric cancer cells by synergistically downregulating EGFR via the PI3K/FOXO3a pathway.

Suppression of JNK/ERK dependent autophagy enhances Jaspine B derivative-induced gastric cancer cell death via attenuation of p62/Keap1/Nrf2 pathways.

Gastric cancer is one of the most common cancers with few effective treatments, a new treatment agent is desperately needed. C-2, a Jaspine B derivative, has shown anti-cancer efficacy in gastric cancer cells. The anti-cancer mechanism, however, remains unknown. As a result, we investigate the anti-cancer effect and the underlying mechanism of C-2 in gastric cancer cells. The results showed that C-2 selectively reduced the proliferation of gastric cancer cells when compared to normal epithelial gastric cells. Western blotting and flow cytometry further demonstrated that Caspase9 is involved in causing cell death. Meanwhile, C-2 triggered autophagy in gastric cancer cells, inhibition of which with LY294002 can enhance the anti-proliferative activity of C-2. Next, we found that C-2 triggered autophagy through activating JNK/ERK, and that inhibitors of these proteins exacerbated C-2 induced cell death. Mechanically, enhanced phosphorylation of JNK/ERK elevated Beclin-1 by disturbing Beclin-1/Bcl-xL or Beclin-1/Bcl-2 complexes, resulting in autophagy and up-regulation of p62. Finally, p62 binds Keap1 competitively to release Nrf2, boosting Nrf2 translocation from the cytoplasm to the nucleus and triggering expression of Nrf2 target genes, so enhancing survival. C-2 inhibited the growth of gastric cancer cells, while JNK/ERK dependent autophagy antagonized C-2 induced cell growth inhibition through p62/Keap1/Nrf2 pathway.