Gastric Cancer Cell Line SGC-7901 Research Articles

Decreased core-fucosylation contributes to malignancy in gastric cancer.

The object of the study is to identify N-glycan profiling changes associated with gastric cancer and explore the impact of core-fucosylation on biological behaviors of human gastric cancer cells. A total of 244 subjects including gastric cancer, gastric ulcer and healthy control were recruited. N-glycan profiling from serum and total proteins in gastric tissues was analyzed by DNA sequencer-assisted fluorophore-assisted capillary electrophoresis. The abundance of total core-fucosylated residues and the expression of enzymes involved in core-fucosylation were analyzed with lectin blot, quantitative reverse transcription-polymerase chain reaction, western blot, Immunohistochemical staining and lectin-histochemical staining. The recombinant plasmids of GDP-fucose transporter and α-1,6-fucosyltransferase (Fut8) were constructed and transfected into gastric cancer cell lines BGC-823 and SGC-7901. CCK-8 and wound healing assay were used to assess the functional impact of core-fucosylation modulation on cell proliferation and migration. Characteristic serum N-glycan profiles were found in gastric cancer. Compared with the healthy control, a trianntenary structure abundance, peak 9 (NA3Fb), was increased significantly in gastric cancer, while the total abundance of core-fucosylated residues (sumfuc) was decreased. Core-fucosylated structures, peak6(NA2F) and peak7(NA2FB) were deceased in gastric tumor tissues when compared with that in adjacent non-tumor tissues. Consistently, lens culinaris agglutinin (LCA)-binding proteins were decreased significantly in sera of gastric cancer, and protein level of Fut8 was decreased significantly in gastric tumor tissues compared with that in adjacent non-tumor tissues. Upregulation of GDP-Tr and Fut8 could inhibit proliferation, but had no significant influence on migration of BGC-823 and SGC-7901 cells. Core-fucosylation is down regulated in gastric cancer. Upregulation of core-fucosylation could inhibit proliferation of the human gastric cancer cells.

Inhibitory Effects of 3-Bromopyruvate on Human Gastric Cancer Implant Tumors in Nude Mice

Gastric cancer is a common malignant tumor. Our previous study demonstrated inhibitory effects of 3-bromopyruvate (3-BrPA) on pleural mesothelioma. Moreover, we found that 3-BrPA could inhibit human gastric cancer cell line SGC-7901 proliferation in vitro, but whether similar effects might be exerted in vivo have remained unclear. To investigate the effect of 3-BrPA to human gastric cancer implant tumors in nude mice. Animals were randomly divided into 6 groups: 3-BrPA low, medium and high dose groups, PBS negative control group 1 (PH7.4), control group 2 (PH 6.8-7.8) and positive control group receiving 5-FU. The TUNEL method was used to detect apoptosis, and cell morphology and structural changes of tumor tissue were observed under transmission electron microscopy (TEM). 3-BrPA low, medium, high dose group, and 5-FU group, the tumor volume inhibition rates were 34.5%, 40.2%, 45.1%, 47.3%, tumor volume of experimental group compared with 2 PBS groups (p<0.05), with no significant difference between the high dose and 5-FU groups (p>0.05). TEM showed typical characteristics of apoptosis. TUNEL demonstrated apoptosis indices of 28.7%, 39.7%, 48.7% for the 3-BrPA low, medium, high dose groups, 42.2% for the 5-FU group and 5% and 4.3% for the PBS1 (PH7.4) and PBS2 (PH6.8-7.8) groups. Compared each experimental group with 2 negative control groups, there was significant difference (p<0.05); there was no significant difference between 5-FU group and medium dose group (p>0.05), but there was between the 5-FU and high dose groups (p<0.05). This study indicated that 3-BrPA in vivo has strong inhibitory effects on human gastric cancer implant tumors in nude mice .

Cetuximab Inhibits Gastric Cancer Growth in vivo, Independent of KRAS Status

Mutation status of Kirsten rat sarcoma viral oncogene homolog (KRAS) may serve as a negative predictive marker of Cetuximab in treating colorectal cancer. The present study was to determine the role of KRAS status in EGFR antibody treatment for gastric cancer. KRAS status was clarified in SGC-7901 (wild type) and YCC-2 (G→A mutation) gastric cancer cell lines. Anti-proliferative and pro-apoptotic effects of Cetuximab were tested both in vitro and in vivo, the expression of phosphorylated (p) ERK, a downstream protein in EGFR-RAS-MEK pathway, was also analyzed. No significant in vitro anti-proliferative or pro-apoptotic effects of Cetuximab were observed in both cell lines. The growth of either SGC-7901 or YCC-2 gastric cancer xenograft was significantly inhibited by Cetuximab. Apoptosis was induced in SGC-7901 but not in YCC-2 xenografts after Cetuximab treatment. The expression of pERK was up-regulated in YCC-2 but not SGC-7901 xenografts after Cetuximab treatment. In conclusion, KRAS (G→A) mutation does not affect in vivo anti-cancer efficacy of Cetuximab.

Establishment of stable SGC-7901 gastric cancer cell line with cortactin down-regulation

Objective To establish a stable SGC-7901 gastric cancer cell line with cortactin downregulation.Methods Three pairs of primers specific to knockdown cortactin and a pair of control primers were designed and synthesized.The primers were annealed and inserted into PLKO.1 plasmids.The plasmids,psPAX2,and PCMV-VSVG were transfected into HEK293T cells simultaneously,and then lentiviral particles were produced and collected.The lentiviral particles were used to infect SGC-7901 cells and puromycin was used to select stable cell lines.Three stable cell lines were selected at last.Real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting were conducted to detect the expression level of cortactin mRNA and protein respectively.Results The expression levels of cortactin mRNA and protein were significantly down-regulated.The mRNA and protein levels of cortactin in PLKO.1 + short hairpin RNA (shRNA)3 cell line were significantly decreased,about 10％ of the control stable cell line.Conclusion The stable SGC-7901 gastric cell lines with cortactin down-regulation were established successfully. Key words: Cortactin; Short hairpin RNA ; Gastric

The effects of microRNA-29a on the growth of human gastric cancer cells transplanted subcutaneously in nude mice

Objective To study the effect of microRNA (miR)-29a on the growth of human gastric cancer cell line SGC-7901 xenografts in nude mice.Methods The SGC-7901 cell line was injected subcutaneously into nude mice to establish the model of human gastric cancer xenografts.The replicationdeficient recombinant adenovirus carrying miR-29a (Ad-miR29a) was injected into the xenografts.The phosphate buffered saline (PBS) solution was employed as blank control and the adenovirus carrying celmiR-67 (Ad-cel) as negative control.The growth curve of the tumor xenografts was observed and the inhibitory rate of tumor was calculated.The expression of miR-29a was detected using real-time reverse transcriptase-polymerase chain reaction (RT-qPCR).The microvessel density (MVD) was calculated by CD34 detection using immunohistochemistry in the xenografts.Results Comparing to the PBS group,the expression level of miR-29a of xenografts in the Ad-miR29a group was significantly up-regulated (3.06 ± 0.73 vs.1.00 ±0.21,P ＜ 0.01),while no significant difference was detected between Ad-cel and PBS group.The growth of xenografts in the Ad-miR29a group was suppressed apparently comparing to the PBS group,while no significant change was detected between Ad-cel and PBS group.At the end of the 5th weekend,the tumor inhibition rate reached 49.30％ in Ad-miR29a group.The MVD counts of xenografts in the Ad-miR29a group were down-regulated significantly comparing to that in PBS group (21.3 ± 8.1 vs.42.6 ± 11.2,P ＜0.01),while no significant change was detected between Ad-cel and PBS group.Conclusion The up-regulation of miR-29a can suppress the growth of gastric cancer xenografts in nude mice by inhibiting the MVD in tumors,which makes miR-29a a promising novel target for gene therapy for human gastric cancer. Key words: MicroRNAs ; Gastric cancer; MicroRNA-29a; Microvessel density

Effect of tissue factor knockdown on the growth, invasion, chemoresistance and apoptosis of human gastric cancer cells.

This study aimed to explore the role of tissue factor (TF) and evaluate its antitumor effects in the biological processes of gastric cancer cells using the application of RNA interference technology to silence TF in the SGC7901 gastric cancer cell line. Specific small interfering RNA (siRNA) designed for targeting human TF was transfected into SGC7901 cells. The expression levels of TF in the cells were detected by reverse transcription-polymerase chain reaction. Cell proliferation and chemosensitivity were measured by Cell Counting Kit-8. The metastatic potential of the SGC7901 cells was determined by Transwell experiments and wound-healing assays. Cell apoptosis was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide double-staining method. The expression levels of TF mRNA were significantly reduced by the TF-siRNA in the SGC7901 cells, resulting in the suppression of cell proliferation, chemoresistance and invasion, and subsequently the induction of cell apoptosis. TF knockdown with siRNA inhibits the growth, invasion and chemoresistance and enhances the apoptosis of SGC7901 cells, providing a potential approach for gene therapy against human gastric cancer.

MiR-7 inhibits the invasion and metastasis of gastric cancer cells by suppressing epidermal growth factor receptor expression

The present study profiled differentially expressed microRNAs (miRs) in gastric cancer cell lines and then investigated miR-7 expression in gastric cancer tissue specimens and the effects of miR-7 on the growth, invasion and metastasis of gastric cancer cells and the underlying molecular events. A microRNA microarray was used to profile differentially expressed miRNAs in human gastric cancer cell lines relative to a normal stomach mucosal epithelial cell line. The miRNA miR-7 was selected for further investigation, which included real-time reverse-transcription PCR (qRT-PCR) analysis of miR-7 levels in different gastric cancer cell lines and tissues and distant non-tumor tissues from patient resections. Cell counting kit-8 (CCK-8), Transwell migration and invasion, and western blot assays were performed to assess tumor cell viability, invasion and gene expression, respectively, after miR-7 transfection. The miRNA microarray profiling revealed 14 upregulated miRNAs (including miR-21, miR-26b and miR-30b) and 19 downregulated miRNAs (including let-7i, miR-7 and miR-622) between gastric cancer and normal cell lines. The qRT-PCR analysis confirmed that reduced miR-7 expression occurred more frequently in poorly and moderately differentiated gastric cancer MGC-803, MKN-45 and SGC-7901 cell lines than in the well-differentiated gastric cancer NCI-N87 cell line, which was consistent with the results for gastric cancer tissues. Expression of miR-7 was downregulated in 86.9% (20/23) of the gastric cancer tissues compared with that in the distant non-tumor tissues. Restoration of miR-7 expression significantly inhibited tumor cell viability, invasiveness and migration when compared with the control cells. Luciferase assay confirmed the epidermal growth factor receptor (EGFR) as a target gene of mR-7, and expression of miR-7 significantly suppressed EGFR expression at both the mRNA and protein levels. The data from the present study demonstrated that reduced miR-7 expression contributes to gastric cancer development and progression. Further study will investigate miR-7 in the regulation of EGFR expression in vitro and in vivo.

MiR-148a regulates MEG3 in gastric cancer by targeting DNA methyltransferase 1

The long non-coding RNA MEG3 has been reported to be a tumor suppressor in a number of malignant tumors including gastric cancer. Several studies have shown that the regulation of MEG3 may attribute to the promoter hypermethylation. However, the mechanism of MEG3 regulation in gastric cancer is still not well understood. MiR-148a can suppress gastric tumorigenesis through regulating the expression of target genes such as DNA methyltransferase 1(DNMT-1). We examined the expression of MEG3 in 52 gastric cancer samples using quantitative real-time PCR and found the down-regulation of MEG3 in both gastric cancer tissues and cell lines. The positive correlation of MEG3 and miR-148a was further confirmed in SGC-7901 and BGC-823 gastric cancer cell lines. Hypermethylation of MEG3 differentially methylated regions was identified by methylation-specific PCR, and MEG3 expression was increased with the inhibition of methylation with siRNA to DNMT-1 in gastric cancer cells. In addition, transfection of MEG3 siRNA into gastric cancer cells diminished the suppression of proliferation induced by overexpression of miR-148a. Our results suggest that the suppression of miR-148a may contribute to the down-regulation of MEG3 in gastric cancer by modulation of DNMT-1.

Lethal effect of a hyperthermic CO2 pneumoperitoneum on gastric cancer cells

We investigated the lethal effect of a hyperthermic CO₂ pneumoperitoneum on gastric cancer cells. This could form the theoretical basis for further studies of the feasibility and safety of inflating hyperthermic CO₂ in the abdominal cavity of gastric cancer patients during laparoscopy. An in vitro hyperthermic CO₂ pneumoperitoneum experimental model was built, where gastric cancer cell line SGC-7901 cells were grouped according to temperature. Cytotoxicity was detected using a cell counting kit; apoptosis was detected by Annexin V-FITC/PI flow cytometry and Hoechst 33342/PI fluorescent microscopy. Morphological alterations were observed by transmission electron microscopy. Invasion and migration were detected by a scratch test and by transwell migration, respectively. Cytotoxicity assays showed that a hyperthermic CO₂ pneumoperitoneum significantly inhibited the proliferation of SGC-7901 cells (P<0.05); it also significantly induced apoptosis of SGC-7901 cells (P<0.05). Morphological observations showed that the cell membrane and nucleus had an apoptotic phenotype. The invasiveness and migration ability of the gastric cancer cells subjected to hyperthermic CO₂ were significantly reduced. A hyperthermic CO₂ pneumoperitoneum had a lethal effect on gastric cancer SGC-7901 cells by inhibiting their invasion and migration, and by inducing apoptosis.

Down-regulation of thyroid hormone receptor β1 gene expression in gastric cancer involves promoter methylation

Hypermethylation has been shown in the promoter region of the thyroid hormone receptor β1 (TRβ1) gene in several human tumors. However, its role in gastric cancer formation is still unclear. In the study, we analyzed mRNA expression of TRβ1 gene using real-time quantitative PCR (qPCR). A quantitative methylation-specific PCR (Q-MSP) assay was used to determine the methylation status of the TRβ1 gene promoter region in 46 pair-matched gastric neoplastic and adjacent non-neoplastic tissues. The results showed that TRβ1 mRNA expression was significantly reduced in gastric cancer specimens. The methylation of promoter of TRβ1 gene in gastric cancer tissues was significantly higher than in adjacent normal tissues. Promoter hypermethylation of the TRβ1 gene correlated with tumor infiltration, lymph node metastasis, and distant metastasis, but it was not associated with other clinicopathological characteristics. We treated gastric cancer cell lines MKN-45, MKN-28, SGC-7901, NCI-N87, and SNU-1 with 5-Aza-2-deoxycytidine (5-Aza-dC). The results showed the expression of TRβ1 mRNA was increased in MKN-45, MKN-28, SGC-7901, but not increased in NCI-N87 and SNU-1. These results suggest that the TRβ1 gene plays important roles in the development of gastric cancer partially through epigenetic mechanisms.

Human gastric cancer cell line SGC-7901 apoptosis induced by SFPS-B2 via a mitochondrial-mediated pathway.

This study was to investigate the effect of Sargassum fusiforme polysaccharides (SFPS-B2) on the proliferation and apoptosis of human gastric cancer cell line SGC-7901. Cells were treated with different concentrations of SFPS-B2. MTT and flow cytometry (FCM) assays were performed to evaluate the effect of SFPS-B2 on the cell growth and apoptosis. Inverted fluorescent microscope was used to observe cell morphology. Laser scanning confocal microscope (LSCM) was used to analyze intracellular calcium ion concentration, mitochondrion permeability transition pore (MPTP) and mitochondrial membrane potential (MMP). Spectrophotometer was applied to quantify the activity of Caspase-9 and Caspase-3. FCM was used to determine the expressions of Bcl-2, Bax and cytochrome C. It was shown that SFPS-B2 inhibited the growth of SGC-7901. After the treatment for 72 h, the cell apoptosis morphology was obvious, which showed that cell protuberance and apoptotic body appeared, and the cytoplasm was concentrated; the apoptotic peak appeared and the apoptotic rate increased in a dose-dependent manner. After the treatment for 24 h, SFPS-B2 activated intracellular MPTP and decreased MMP. It also increased the activity of Caspase-9 and Caspase-3, down-regulated the expression of Bcl-2 and up-regulated the expression of Bax, induced the release of Cyt-C. SFPS-B2 induced SGC-7901 apoptosis through a mitochondrial-mediated pathway, suggesting it may be an agent for cancer treatment.

Effect of TRAIL in combination with DDP on the expression of MDR1 gene in gastric cancer cells.

IntroductionGastric cancer is one of the most common malignant tumor, and gastric cancer is the second most common cause of cancer mortality worldwide. Although chemotherapy is one of the most important treatment options for gastric cancer, and could improve the overall survival rate and quality of live, one significant reason for its failure is multidrug resistance (MDR).AimTo study the effect of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) combined with chemotherapeutic drug cisplatin (DDP) on the expression of multidrug resistance gene 1 (MDR1) in the gastric cancer cell line SGC-7901/VCR.Material and methodsSGC-7901/VCR cells were cultured with DDP and TRAIL in various concentrations. The apoptosis rate was separately measured by a flow cytometer in DDP (sub-toxic dose) alone, TRAIL (200 µg/l) alone and in a combination of the two. Expression levels of MDR1 mRNA and P-glycoprotein (P-gp) were detected by RT-PCR and ELISA analysis, respectively.ResultsThe apoptosis rate in the combination group was significantly higher than that in the other groups (p < 0.05). According to the results of RT-PCR and ELISA, the expressions of MDR1 mRNA and P-gp in the combination group were statistically significant different compared with other groups (p < 0.05).ConclusionsThe combination of TRAIL with DDP could reverse MDR phenotype in gastric cancer cell line SGC7901/VCR. The mechanism may be involved in the down-regulation of MDR1 mRNA and P-gp, which may play an essential role in overcoming the chemotherapeutic resistance of gastric cancer cells. This study indicates that a combination of chemotherapy and TRAIL may be an effective strategy to treat MDR gastric cancer.

Attenuation of enoyl coenzyme A hydratase short chain 1 expression in gastric cancer cells inhibits cell proliferation and migration in vitro.

Enoyl coenzyme A hydratase short chain 1 (ECHS1) is an important part of the mitochondrial fatty acid β-oxidation pathway. Altered ECHS1 expression has been implicated in cancer cell proliferation. This study assessed ECHS1 expression in human gastric cancer cell lines and investigated the effects of ECHS1 knockdown on gastric cancer cell proliferation and migration. The human gastric cancer cell lines SGC-7901, BGC-823 and MKN-28, and the immortalized human gastric epithelial mucosa GES-1 cell line were analyzed for ECHS1 protein levels using western blot. The effectiveness of ECHS1-RNA interference was also determined using western blot. Proliferation and migration of the siECHS1 cells were respectively measured with the CCK-8 and transwell assays. Phosphorylation of PKB and GSK3β was assessed using western blot. ECHS1 protein levels were significantly higher in poorly differentiated cells than in well-differentiated cells and immortalized gastric epithelial mucosa cells. Stable expression of ECHS1 shRNA was associated with an over 41% reduction in the ECHS1 protein levels of siECHS1 cells. Constitutive knockdown of the ECHS1 gene in siECHS1 cells was associated with significantly inhibited cell proliferation and migration. We also observed decreased levels of PKB and GSK3β phosphorylation in siECHS1 cells. ECHS1 expression is increased in human gastric cancer cells. Increased ECHS1 expression activates PKB and GSK3β by inducing the phosphorylation of the two kinases. ECHS1 may play important roles in gastric cancer cell proliferation and migration through PKB- and GSK3β-related signaling pathways.

ZNF139 promotes tumor metastasis by increasing migration and invasion in human gastric cancer cells.

Zinc finger protein 139(ZNF139), a member of zinc finger protein family, is a transcription factor. Our previous research showed ZNF139 was overexpressed in gastric cancer cells. The purpose of present study is to explore impact and mechanism of ZNF139 on metastasis by regulating invasive ability of gastric cancer cells. Quantitative RT-PCR(QRT-PCR) and Western blot were applied for detection of ZNF139 expression in gastric cancer tissues, adjacent cancer tissues, metastatic lymph nodes, gastric cancer cell lines SGC7901 and BGC823 and gastric epithelial cell line GES-1; siRNA specific to ZNF139 was synthesized and then transfected into gastric cancer cell line BGC823; wound healing assay and Transwell assay were used to observe impact of ZNF139-siRNA after being transfected into BGC823 on its invasion and migration; changes in expression of invasion and migration-related genes MMP-2, MMP-9, ICAM-1 and TIMP1 were detected before and after transfection. Gelatin zymogrphy assay were applied to determine the MMP activities. Statistical analysis was based on the SPSS11.5 software.Expression of ZNF139 in gastric adenocarcinoma tissues and cells was significantly higher than the expression in the adjacent cancer tissues, but lower than the expression in the metastatic lymph nodes; ZNF139 expression was present in gastric cancer cell lines, and the expression level was higher than that in normal gastric epithelial cells lines. ZNF139-siRNA significantly inhibited the invasion and migration activity of gastric cancer cell line BGC823. 48h after ZNF139-siRNA was transfected into gastric cancer cell line BGC823, expression and activity of invasion-related genes MMP-2, MMP-9, ICAM-1 mRNA and protein were significantly inhibited, while expressions of TIMP-1 mRNA and protein were significantly increased. At the same time, the gelatinase activities of MMP2 and MMP9 were decreased by ZNF139 interference.ZNF139 was overexpressed in gastric cancer cells, and the expression was further enhanced in the metastasis process. Knocking down ZNF139 expression in gastric cancer cells could effectively reduce gastric cancer cell invasion and migration ability, and this process might play a role by regulating MMP-TIMP balance.

Effects of sufentanil on human gastric cancer cell line SGC-7901 in vitro.

Sufentanil is a new kind of opioid analgesic and acts on μ opioid receptor. In this study, we aim to investigate the effects of sufentanil on gastric cancer cell line SGC-7901, after being exposed to different concentrations of sufentanil. Gastric cancer cells were exposed to sufentanil for a predetermined time at concentrations of 0, 0.5, 5, 50 and 500 nmol/l, respectively. Cell viability at different time points after exposure to sufentanil was tested by CCK-8 assay. FDA-PI staining was used to observe membrane integrity of gastric cancer SGC7901 cells. The apoptosis of gastric cancer cells was analyzed by Annexin V-FITC/PI Flow Cytometry and the changes of the cell cycle was determined by a detection kit. As a result, cell viability decreased in a dose- and time-dependent manner. Furthermore, with the concentration of sufentanil increased, the proportion of dead and apoptotic SGC-7901 cells increased, and more cells were arrested in G2/M phase. In a word, sufentanil can inhibit the cell viability and induce the apoptosis of gastric cancer SGC-7901 cells in vitro.

PBX3 is overexpressed in gastric cancer and regulates cell proliferation

The pre-leukemia transcription factor 3 (PBX3) is a member of the PBX family of transcription factors, which is known to increase DNA-binding/transcriptional activity of HOX proteins and regulate genes involved in development. Recently, PBX3 was reported to be involved in a variety of cancers, while its implication in gastric cancer is unclear. This study aimed to investigate its clinical significance and biological function in gastric cancer. PBX3 expression was analyzed in 90 gastric cancer specimens using immunohistochemistry. PBX3 was overexpressed in 30 cases (33.33%). Importantly, PBX3 overexpression positively correlated with advanced invasion depth (p = 0.0017), Clinical stage (p = 0.0127) and grade of tumor differentiation (p = 0.0158). PBX3 was also overexpressed in gastric cancer cell lines. Plasmid transfection was performed in AGS and SGC-7901 gastric cancer cell line with low endogenous PBX3 expression. MTT and colony formation assay were carried out to assess the role of PBX3 in proliferation. PBX3 overexpression in gastric cancer cell lines accelerated cell proliferation rate and colony formation ability, with upregulation of PCNA expression. In addition, matrigel invasion assay showed that PBX3 transfection also increased cell-invading ability. These results validate the role of PBX3 as a clinically relevant oncoprotein and establish PBX3 as a promising therapeutic target of gastric cancer.

Facile Preparation of Paclitaxel Loaded Silk Fibroin Nanoparticles for Enhanced Antitumor Efficacy by Locoregional Drug Delivery

Non-toxic, safe materials and preparation methods are among the most important factors when designing nanoparticles (NPs) for future clinical application. Here we report a novel and facile method encapsulating anticancer drug paclitaxel (PTX) into silk fibroin (SF), a biocompatible and biodegradable natural polymer, without adding any toxic organic solvents, surfactants or other toxic agents. The paclitaxel loaded silk fibroin nanoparticles (PTX-SF-NPs) with a diameter of 130 nm were formed in an aqueous solution at room temperature by self-assembling of SF protein, which demonstrated mainly silk I conformation in the NPs. In cellular uptake experiments, coumarin-6 loaded SF NPs were taken up efficiently by two human gastric cancer cell lines BGC-823 and SGC-7901. In vitro cytotoxicity studies demonstrated that PTX kept its pharmacological activity when incorporating into PTX-SF-NPs, while SF showed no cytotoxicity to cells. The in vivo antitumor effects of PTX-SF-NPs were evaluated on gastric cancer nude mice exnograft model. We found that locoregional delivery of PTX-SF-NPs demonstrated superior antitumor efficacy by delaying tumor growth and reducing tumor weights compared with systemic administration. Furthermore, the organs of mice in NP treated groups didn't show obvious toxicity, indicating the in vivo safety of SF NPs. These results suggest that SF NPs are promising drug delivery carriers, and locoregional delivery of SF NPs could be a potential future clinical cancer treatment regimen.

Expression of ZBTB8A in gastric cancer and its clinical significance

To investigate the expression of ZBTB8A (zinc finger and BTB domain containing 8A) in gastric cancer tissues and its clinical significance. Level of ZBTB8A mRNA in human normal gastric cell line GES-1, human gastric cancer cell line SGC7901 and MGC803 was detected by real-time PCR. Levels of ZBTB8A mRNA and protein in cancer tissues, adjacent cancer tissues from 104 cases with primary gastric cancer and normal gastric mucosal tissues from 40 cases without malignant gastric diseases were detected by RT-PCR and immunohistochemistry, respectively. Association between ZBTB8A expression and clinicopathology was analyzed. ZBTB8A mRNA expressions in SGC7901, MGC803 and GES-1 cells were 0.00138±0.00015, 0.00158±0.00021, 0.00036±0.000055, respectively, and differences among SGC7901, MGC803 and GES-1 were significant respectively (all P<0.05). ZBTB8A mRNA expression was significantly up-regulated in cancer tissues as compared to adjacent cancer tissues and normal tissues (0.0152±0.0126 vs. 0.0070±0.0061 and 0.0079±0.0036, all P>0.05), while no significant difference was found between adjacent cancer tissues and normal tissues (P>0.05). ZBTB8A expression was significantly associated with invasive depth, lymph node metastasis, tumor stage, and degree of adenocarcinoma differentiation (all P<0.05), but not with age, gender, histological type,gross type (all P>0.05). ZBTB8A may be a potential carcinogenic factor in gastric carcinoma, and may also be involved in gastric adenocarcinoma cell differentiation, cancer invasion and metastasis.

Synthesis, anti-tumor activity, and structure–activity relationships of curcumol derivatives

Using curcumol that was extracted from the volatile oil of Rhizoma Curcumae as the raw material, its derivatives were synthesized and purified. The structures of these compounds were confirmed by 1H, 13C NMR, and mass spectral data. The test compounds were evaluated for their in vitro anti-tumor activity against gastric cancer cell lines SGC-7901 and lung carcinoma cell line H460 by methyl thiazolyl tetrazolium chromatometry. Distinct structure–activity relationships of these curcumol derivatives were also revealed for inhibiting cell proliferation. Presence of electron-withdrawing groups or amino could increase the activity significantly, whereas esterification of 8-hydroxy diminished the anti-tumor activity. Many of the tested candidates exhibited higher inhibition efficiency than curcumol, suggesting that structural modifications could enhance its activity effectively.

MiR-449a Regulates Proliferation and Chemosensitivity to Cisplatin by Targeting Cyclin D1 and BCL2 in SGC7901 Cells

Recently, several miRNAs have been determined as tumor suppressors in various cancers, such as microRNA-449a. However, the exact molecular mechanisms underlying miR-449a regulated cell proliferation and chemosensitivity in gastric cancer cells have not been well documented. The present study was designed to test whether miR-449a mediates cell proliferation and chemosensitivity in gastric cancer cells via regulating cyclin D1 and BCL2. In vitro, the ability of cell proliferation and cell viability were measured by MTT assay; cell cycle and cell apoptosis was detected by FCM. qRT-PCR was used to measure the expression of miR-449a. Western blot and real-time PCR assays were used to detect the expression of cyclin D1 and BCL2 in gastric cancer cell line SGC7901. miR-449a expression was downregulated in gastric cancer cell line SGC7901 and human gastric cancer tissues, compared to the gastric epithelial cell line GES-1 and matched non-tumor associated tissues. Upregulation of miR-449a reduced the proliferation of SGC7901 cells. Ectopic expression of miR-449a decreased the percentage of S phase cells, increased the percentage of G1/G0 phase cells and increased the apoptosis induced by cisplatin. Moreover, miR-449a inhibited SGC7901 cells proliferation and enhanced cisplatin chemosensitivity by downregulating expression of BCL2 and cyclin D1, respectively, via directly targeting the 3'-untranslated regions of BCL2 and cyclin D1 mRNA. This is the first report to provide evidence that miR-449a could modulate cell cycle and apoptosis through regulating cyclin D1 and BCL2 expression in SGC7901 cells.