Human Gastric Carcinoma Cell Research Articles

Coordinated expression of REG4 and aldehyde dehydrogenase 1 regulating tumourigenic capacity of diffuse‐type gastric carcinoma‐initiating cells is inhibited by TGF‐β

Aldehyde dehydrogenase 1 (ALDH1) has been shown to serve as a marker for cancer-initiating cells (CICs), but little is known about the regulation of the CIC functions of ALDH1+ cancer cells. We isolated ALDH1+ cells from human diffuse-type gastric carcinoma cells and characterized these cells using an Aldefluor assay. ALDH1+ cells constituted 5-8% of the human diffuse-type gastric carcinoma cells, OCUM-2MLN and HSC-39; were more tumourigenic than ALDH1- cells; and were able to self-renew and generate heterogeneous cell populations. Using gene expression microarray analyses, we identified REG4 (regenerating islet-derived family, member 4) as one of the genes up-regulated in ALDH1+ cells, and thus as a novel marker for ALDH1+ tumour cells. Induced expression of REG4 enhanced the colony-forming ability of OCUM-2MLN cells, while knockdown of REG4 inhibited the tumourigenic potential of ALDH1+ cells. We further found that TGF-β signalling reduces the expression of ALDH1 and REG4, and the size of the ALDH1+ cell population. In human diffuse-type gastric carcinoma tissues, the expression of ALDH1 and REG4 correlated with each other, as assessed by immunohistochemistry, and ALDH1 expression correlated inversely with Smad3 phosphorylation as a measure of TGF-β signalling. These findings illustrate that, in diffuse-type gastric carcinoma, REG4 is up-regulated in ALDH1+ CICs, and that the increased tumourigenic ability of ALDH1+ cells depends on REG4. Moreover, TGF-β down-regulates ALDH1 and REG4 expression, which correlates with a reduction in CIC population size and tumourigenicity. Targeting REG4 in ALDH1+ CICs may provide a novel strategy in the treatment of diffuse-type gastric carcinoma.

Syntheses and antiproliferative activity of some sulfated hydroximinosterols

Four new sulfated steroidal compounds, sodium 3-hydroxy-6-hydroximinocholestane 3-sulfate (7a), sodium 3-hydroxy-6-hydroximinostigmastane 6-sulfate (7b), sodium 3-hydroxy-6-hydroximinocholest-4-ene 3-sulfate (10a), and sodium 6-hydroxy-3-hydroximinocholestane 6-sulfate (16) had been synthesized using cholesterol or stigmasterol as starting materials by different synthetic methods. The synthetic compounds were characterized by their analytical and spectral data, and their antiproliferative activity against MGC 7901 (human gastric carcinoma cell line), HeLa (human cervical carcinoma cell line), and SMMC 7404 (human liver carcinoma cell line) were investigated. The results showed that the compounds exhibited a remarkable cytotoxicity against HeLa tumor cells in vitro and 7a displayed a better cytotoxicity than cisplatin (a positive contrast).

Inhibition of Chemokine (CXC Motif) Ligand 12/Chemokine (CXC Motif) Receptor 4 Axis (CXCL12/CXCR4)-mediated Cell Migration by Targeting Mammalian Target of Rapamycin (mTOR) Pathway in Human Gastric Carcinoma Cells

CXCL12/CXCR4 plays an important role in metastasis of gastric carcinoma. Rapamycin has been reported to inhibit migration of gastric cancer cells. However, the role of mTOR pathway in CXCL12/CXCR4-mediated cell migration and the potential of drugs targeting PI3K/mTOR pathway remains unelucidated. We found that CXCL12 activated PI3K/Akt/mTOR pathway in MKN-45 cells. Stimulating CHO-K1 cells expressing pEGFP-C1-Grp1-PH fusion protein with CXCL12 resulted in generation of phosphatidylinositol (3,4,5)-triphosphate, which provided direct evidence of activating PI3K by CXCL12. Down-regulation of p110β by siRNA but not p110α blocked phosphorylation of Akt and S6K1 induced by CXCL12. Consistently, p110β-specific inhibitor blocked the CXCL12-activated PI3K/Akt/mTOR pathway. Moreover, CXCR4 immunoprecipitated by anti-p110β antibody increased after CXCL12 stimulation and G(i) protein inhibitor pertussis toxin abrogated CXCL12-induced activation of PI3K. Further studies demonstrated that inhibitors targeting the PI3K/mTOR pathway significantly blocked the chemotactic responses of MKN-45 cells triggered by CXCL12, which might be attributed primarily to inhibition of mTORC1 and related to prevention of F-actin reorganization as well as down-regulation of active RhoA, Rac1, and Cdc42. Furthermore, rapamycin inhibited the secretion of CXCL12 and the expression of CXCR4, which might form a positive feedback loop to further abolish upstream signaling leading to cell migration. Finally, we found cells expressing high levels of cxcl12 were sensitive to rapamycin in its activity inhibiting migration as well as proliferation. In summary, we found that the mTOR pathway played an important role in CXCL12/CXCR4-mediated cell migration and proposed that drugs targeting the mTOR pathway may be used for the therapy of metastatic gastric cancer expressing high levels of cxcl12.

PI3K/Akt signalling is required for the attachment and spreading, and growth in vivo of metastatic scirrhous gastric carcinoma

Background:PI3K/Akt (PKB) pathway has been shown in several cell types to be activated by ligands to cell surface integrins, leading to the metastasis of tumour cells. The signalling pathways involved in the metastatic spread of human scirrhous gastric carcinoma cells have not been defined.Methods:The role of the PI3K/Akt pathway in an extensive peritoneal-seeding cell line, OCUM-2MD3 and a parental cell line, OCUM-2M, was investigated by assessing in vitro adhesion and spreading assay, and in vivo peritoneal metastatic model. We also examined the correlation of PI3K/Akt pathway with integrin signals by immunoprecipitations, using cells by transfection with mutant p85 (Δp85).Results:Adhesiveness and spreading of OCUM-2MD3 cells on collagen type IV was significantly decreased by PI3K inhibitors and expression of mutant p85, but not by inhibitors of protein kinase C (PKC) or extracellular signal-regulated kinase (ERK). Immunoprecipitation studies indicated that the PI3K/Akt pathway was associated with integrin signalling through Src and vinculin. In an in vivo experimental metastasis model, p85 inhibition reduced peritoneal metastasis of OCUM-2MD3 cells.Conclusion:PI3K/Akt signalling may be required for integrin-dependent attachment and spreading of scirrhous gastric carcinoma cells, and would be translated into generating better strategies to optimise their use in cancer clinical trials.

Isolation and characterization of side population cells in human gastric cancer cell line BGC-823

Isolate and characterize the side population (SP) cells with potency of stem cells from human gastric carcinoma cell line BGC-823. SP and non-SP cells were sorted from BGC-823 cells by fluorescence-activated cell sorting (FACS) using Hoechst33342 staining. The tumorigenic ability of the SP cells was assessed by in vivo transplantation into non-obese diabetic/severe combined immunodeficiency mice. SP cells were isolated from BGC-823 cells in a proportion of 0.9% to 2.1% with respect to the whole cell population. The colony formation assay showed that the colony formation rate of the SP cells was significantly higher than that of the non-SP cells (72.56% vs. 49.00%, P < 0.01). The drug sensitivity test showed that the SP cells showed stronger drug resistance to 5-Fu than the non-SP cells. The in vivo transplantation of SP cells in mice showed that the tumor weight was (0.176 ± 0.034) g, significantly higher than that of non-SP cells (0.045 ± 0.046) g (P < 0.01). The results of this study indicate the existence of cancer stem-like SP cells in the human gastric cancer line BGC-823 cells. Further characterization of this SP cell population may provide new insights for diagnosis and treatment of gastric cancer.

Overexpression of ZEB1 associated with metastasis and invasion in patients with gastric carcinoma

The aim of this study was to investigate the expression of ZEB1 in gastric carcinoma, its correlation with the clinicopathology of gastric carcinoma, and the role of ZEB1 in invasion and metastasis in gastric carcinoma. ZEB1 expression was analyzed by immunohistochemistry and Western blot in 45 gastric carcinoma tissue samples that contained the adjacent gastric mucosa. The correlation between ZEB1 expression, the occurrence and development of gastric cancer, and clinical pathology was investigated. ZEB1 expression in the human gastric carcinoma cell line AGS was downregulated by RNA interference, and changes in ZEB1 expression corresponded with changes in the invasive and metastatic ability of AGS cells. Immunohistochemistry revealed that ZEB1 protein expression in gastric carcinoma tissues was significantly higher than in normal gastric mucosa tissues (p < 0.001). A lower degree of differentiation of gastric cancer (p = 0.009), a higher TNM (tumor, node, and metastasis) stage (p = 0.010), and a larger scope of invasion were correlated with higher expression of ZEB1 (p = 0.041, 0.002). However, the expression of ZEB1 in gastric carcinoma tissue was independent of gender, age, and tumor size (p > 0.05). Western blot results also showed that ZEB1 protein expression was significantly higher in gastric carcinoma tissue than in the adjacent normal gastric mucosa tissue (p = 0.008). A lower degree of differentiation of the gastric carcinoma correlated with a higher TNM stage, and a larger scope of invasion correlated with increased ZEB1 expression (p = 0.023). Transfection of ZEB1 siRNA in AGS cells significantly decreased the expression level of ZEB1 protein (p = 0.035). Furthermore, the number of cells that could pass through the Transwell chamber was significantly lower in the transfected group than in the non-transfected control group (p = 0.039), indicating that the suppression of ZEB1 expression could significantly reduce the invasive and metastatic ability of AGS cells (p = 0.005). Concluding, in gastric carcinoma tissue, overexpression of ZEB1 may be related to the occurrence and development as well as invasion and metastasis of gastric carcinoma.

MicroRNA-21 inhibits Serpini1, a gene with novel tumour suppressive effects in gastric cancer

BackgroundA thorough understanding of gastric cancer at the molecular level is urgently needed. One prominent oncogenic microRNA, miR-21, was previously reported to be upregulated in gastric cancer. MethodsWe performed an unbiased search for downstream messenger RNA targets of miR-21, based on miR-21 dysregulation, by using human tissue specimens and the MKN28 human gastric carcinoma cell line. Molecular techniques include microRNA microarrays, cDNA microarrays, qRT-PCR for miR and mRNA expression, transfection of MKN28 with miR-21 inhibitor or Serpini1 followed by Western blotting, cell cycle analysis by flow cytometry and luciferase reporter assay. ResultsThis search identified Serpini1 as a putative miR-21 target. Luciferase assays demonstrated direct interaction between miR-21 and Serpini1 3′UTR. miR-21 and Serpini1 expression levels were inversely correlated in a subgroup of gastric cancers, suggesting a regulatory mechanism that included both of these molecules. Furthermore, Serpini1 induced growth retardation of MKN28 and induced vigorous G1/S arrest suggesting its potential tumour-suppressive function in the stomach. ConclusionTaken together, these data suggest that in a subgroup of gastric cancers, miR-21 is upregulated, inducing downregulation of Serpini1, which in turn releases the G1–S transition checkpoint, with the end result being increased tumour growth.

Downregulation of phosphatase of regenerating liver-3 is involved in the inhibition of proliferation and apoptosis induced by emodin in the SGC-7901 human gastric carcinoma cell line

Emodin, an anthraquinone derivative isolated mainly from the root and rhizome of the medicinal plant Rheum palmatum L., was found to exert anticancer effects on various cultured cancer cells. Phosphatase of regenerating liver-3 (PRL-3), a novel gene, has been known to play an important role in the promotion of cellular proliferation as well as inhibition of apoptosis in cancer cells. However, there is relatively little information in the published literature with regard to the anticancer mechanism of emodin, and whether emodin is involved in the regulation of PRL-3 in human gastric carcinoma cells is not known. In the present study, we investigated the effects of emodin on SGC-7901 cell proliferation, apoptosis and regulation of PRL-3. The results showed that the proliferation of SGC-7901 cells was inhibited by emodin in a time- and concentration-dependent manner. The results also showed that early apoptosis rates increased in a concentration-dependent manner after emodin treatment. Furthermore, real-time quantitative PCR analysis showed that PRL-3 mRNA was significantly decreased by treatment with emodin. Western blotting showed that PRL-3 protein expression was also downregulated significantly. Overall, the present study demonstrated that emodin inhibited cell growth and induced apoptotic cell death in the SGC-7901 human gastric carcinoma cell line. Downregulation of PRL-3 is involved in the inhibition of proliferation and apoptosis induced by emodin. PRL-3 may be a new potential therapeutic target for gastric cancer using emodin.

Cloning and characterization of the porcine IL-10 promoter

Interleukin 10 (IL-10) is an anti-inflammatory and immunosuppressive cytokine that plays an important role in regulating the immune response. Therefore, understanding how IL-10 is regulated is important. The regulatory elements have been well studied in human and mouse promoters and several transcription factors have been showed to be involved in IL-10 transcription. In our study, a 1.5kb fragment of the 5′ flanking region of IL-10 gene was cloned and functionally characterized. Several putative regulatory elements including IRF, AP-1, Sp1, C/EBP, and STAT binding sites were found in the porcine IL-10 (pIL-10) promoter. The pIL-10 promoter deletion mutants were analyzed for their ability to direct luciferase expression in a porcine macrophage cell line (CRL 2843), human gastric carcinoma cell lines with or without Epstein-Barr virus (EBV), AGS–EBV and AGS cell lines. Our data showed that the minimal active pIL-10 promoter region was from −605 to +19, with the inducible activity requiring only one key DNA element, the Sp1 binding site (−398 to −393) upstream of the IL-10 gene starting point in both LPS-stimulated CRL 2843 and AGS–EBV cells. Moreover, our results suggested that the two IRF binding sites (−950 to −942 and −662 to −640) may have a positive role in the activation of the pIL-10 promoter in AGS-EBV cells, but not in LPS-stimulated CRL 2843 cells. These data implicate that the cloned porcine IL-10 promoter could be used to explore the molecular mechanisms underlying the regulation of IL10 production in pigs.

Establishment of the cultured model of microencapsulated human gastric carcinoma cells SGC-7901

Objective To establish the cultured model of microencapsulated human gastric carcinoma (HGC) cell line SGC-7901.Methods The SGC-7901 cells were cultured and encapsulated in APA microcapsules using the prepared electrostatic droplet generator for 21 days.The level of proliferation and metabolism of the microencapsulated HGC cells were detected by using methyl thiazol tetrazolium ( MTT),and glucose and lactic acid concentrations were determined in the supernatant.Microencapsulated HGC cells were stained with hematoxylin and eosin (HE),and the expression of bromodeoxyuridine ( BrdU),vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) gene was detected by using immunocytochemistry on the 7th,14th and 21st day.Monolayer cultured cells served as controls.Results On the 14th day,the relative number of the microencapsulated cells was no longer increased and decreased slightly on the next few days.Glucose was consumed and its concentration was decreased to 10 mmol/L,and lactic acid was generated and its concentration was increased to 100 mol/L in microencapsulated HGC cells on the 20th day.The expression of PCNA and VEGF gene could be detected in SGC7901 cells.The expression of BrdU,PCNA and VEGF was still detected in the microencapsulated SGC9701 cells on the 7th and 14th day.On the 21st day,the expression of Brdu and PCNA was found on the outer layer of spheroid,and that of VEGF gene was detected within the whole spheroid.Conclusion The cultured model of microencapsulated HGC SGC9701 had been established,and gene expression was stable. Key words: Gastric carcinoma; Microencapsulation; Bromodeoxyuridine; Proliferating cell nuclear antigen; Vascular endothelial growth factor

Two new oleanane-type saponins from the husks of Xanthoceras sorbifolia Bunge

Two new oleanane-type pentacyclic triterpenoid saponins were isolated from the husks of Xanthoceras sorbifolia Bunge and their structures were elucidated as 3-O-β-D-glucopyranosyl (1 → 6)-β-D-glucopyranosyl-28-O-α-L-rhamnopyranosyl (1 → 2) [β-D-glucopyranosyl (1 → 6)] β-D-glucopyranosyl-21β,22α-dihydroxyl-olean-12,15-diene and 3-O-β-D-glucopyranosyl (1 → 2)-β-D-glucopyranosyl-28-O-α-L-rhamnopyranosyl (1 → 2) [β-D-glucopyranosyl (1 → 6)] β-D-glucopyranosy-21β,22α-dihydroxyl-olean-12-ene. Meanwhile, the cytotoxic activities of these two compounds were tested on human gastric cancer cell (SGC-7901) and hepatoma carcinoma cell (HepG-2).

Galectin-1 is up-regulated by RASSF1A gene in human gastric carcinoma cell line SGC7901

We have previously shown that overexpression of RASSF1A inhibits the growth of human gastric cancer SGC7901 cells, but the underlying mechanism remains unknown. In this study, the differential protein expression by RASSF1A gene in human gastric cancer cell line SGC7901 was determined by 2-D gel electrophoresis combined with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and bioinformatics. Differential expression analysis of the protein profiles by RASSF1A gene identified a total of 35 protein spots, of which 10 were up-regulated and 25 were down-regulated. Eight proteins were identified by MALDI-TOF MS: Galectin-1, TRP-14, ACBP, PSMB5, PSMB4, TIM, vimentin, CD79α. RASSF1A up-regulated the mRNA expression of Galectin-1, TRP-14, ABCP in SGC7901. RASSF1A also led to an increased expression of Galectin-1 protein in SGC7901 confirmed by western blotting and immunocytochemistry analysis. RASSF1A inhibited the activity of NF-κB in SGC7901 cells. These data indicated that Galectin-1 may be playing a role in RASSF1A signaling in SGC7901.

Establishment and characterization of six human gastric carcinoma cell lines, including one naturally infected with Epstein-Barr virus

We report the characterization of six new gastric carcinoma cell lines (designated NCC-19, NCC-20, NCC-24, NCC-59, SNU-1750 and SNU-1967) established from primary tumor samples of Korean patients. Four cell lines grew as adherent monolayers, one as both adherent and floating cell clumps and one as floating cell aggregates. The cell phenotypes, including the histopathology of the primary tumors and in vitro growth characteristics, were determined. We also performed molecular characterization, including DNA fingerprinting analysis and abnormalities of K-ras, p53, β-catenin, and TGF-βRII genes by PCR-SSCP and sequencing analyses. Population doubling times varied from 47-135h. All cell lines showed relatively high viability, absence of mycoplasma or bacteria contamination and genetic heterogeneity by DNA fingerprinting analysis. Three lines had p53 mutations; one line had mutations in codon 13 (Gly13Asp) in K-ras and no line had a β-catenin mutation. NCC-59 cell line had a -1-bp mutation in 10-bp poly deoxy adenine repeat tract of the TGF-βRII gene. Moreover, NCC-24 gastric cancer cell line was found to be infected with Epstein-Barr virus (EBV). EBV infection was also shown in the original carcinoma tissue of the NCC-24 cell line. These well-characterized six gastric cancer cell lines should serve as useful tools for investigating the biological characteristics of gastric cancer and, in particular, NCC-24 may serve as a valuable model system to clarify the precise role of EBV in gastric carcinogenesis.

Cytotoxicity of dioscin in human gastric carcinoma cells through death receptor and mitochondrial pathways

In the present study, the antiproliferative effect of dioscin on human gastric carcinoma SGC-7901 cells was confirmed by 3-(4, 5-dimethylthiahiazo-zyl)-2, 5-dip-henytetrazolium bromide and flow cytometry assays. Through acridine orange-ethidium bromide double fluorescent staining, apoptotic morphology of the cells was observed. Radioimmunoassays showed that the tumor necrosis factor (TNF)-α concentration in cells treated with dioscin significantly increased compared with untreated cells. Several proteins and mRNA related to the mitochondrial and death receptor pathways were investigated. We found that the expression of Bid, bcl-2 and bcl-xl was markedly downregulated, and the expression of Bak and Bax was upregulated. In addition, cytochrome c was released from the mitochondria into the cytosol, which indicates activation of the mitrochondrial pathway by dioscin. Furthermore, upregulation of Fas, FasL (Fas ligand), TNF-α, TNF receptor-1, TNF receptor-associated factor 1 and Fas-associated protein with death domain demonstrated involvement of the death receptor pathway. Increased mRNA expression of p53 was also found in dioscin-treated SGC-7901 cells, and the activation of caspase-3 and -8 was also observed. Consequently, this study clarifies the mechanism underlying the anticancer effect of dioscin, and also indicates that dioscin may be a potential drug treatment for human gastric cancer.

Total Polyphenols, Antioxidant and Antiproliferative Activities of Different Extracts in Mungbean Seeds and Sprouts

The aim of this investigation was to evaluate the biological, alcohol dehydrogenase (ADH) and antiproliferative activities of different extracts of mungbean seeds and sprouts. All extracts from the sprouts showed higher contents of total phenolics (TP), total flavonoids (TF), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than from seeds. The highest DPPH and tyrosinase inhibition activities were registered in ethyl acetate (EtOAc) extract. ADH activity of methanol (MeOH), n-hexane (n-hexane) and n-butanol (n-BuOH) extracts from sprouts was significantly higher (P < 0.05) than from seeds. However, the highest ADH activity was found in water extract of seeds. According to 3-(4, 5-dimethylthiazol -2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay, extracts from sprouts were more effective against Calu-6 (human pulmonary carcinoma) and SNU-601 (human gastric carcinoma) cells than from seeds. EtOAc extract showed the highest antiproliferative activity in both sprouts and seeds, followed by n-hexane extraction. During sprouting of mungbean, all the studied components significantly increased. In conclusion, the extracts of sprouts are more effective than from seeds and could be a potential source of antioxidants linked with health benefits.

Cytotoxic Triterpenoid Saponins fromArdisia gigantifolia

Three new triterpenoid saponins, 1- 3, together with two known saponins, 4 and 5, were isolated from the rhizome of Ardisia gigantifolia. Their structures were elucidated by 1D and 2D NMR spectroscopic studies. Saponins 1, 2, 4, and 5 exhibited significant cytotoxicity against four human cancer cell lines, namely, Hela human cervical carcinoma cells, EJ human bladder tumor cells, HepG-2 human hepatoma cells, and BCG human gastric carcinoma cells with IC (50) values in the range of 1.9-4.8 µM.

Plasminogen activator inhibitor 1 RNAi suppresses gastric cancer metastasis in vivo

Cancer metastasis remains the primary cause of pain, suffering, and death in cancer patients, and even the most current therapeutic strategies have not been highly successful in preventing or inhibiting metastasis. In most patients with scirrhous gastric cancer (one of the most aggressive of diffuse-type gastric cancer), recurrence occurs even after potentially curative resection, most frequently in the form of peritoneal metastasis. Given that the occurrence of diffuse-type gastric cancers has been increasing, the development of new strategies to combat metastasis of this disease is critically important. Plasminogen activator inhibitor-1 (PAI-1) is a critical factor in cancer progression; thus, PAI-1 RNAi may be an effective therapy against cancer metastasis. In the present study, we used an RNAi technique to reduce PAI-1 expression in an in vivo model system for gastric cancer metastasis. Ex vivo plasmid transfection and adenovirus infection were tested as mechanisms to incorporate specific PAI-1 RNAi vectors into human gastric carcinoma cells. Both approaches significantly decreased peritoneal tumor growth and the formation of bloody ascites in the mouse model, suggesting that this approach may provide a new, effective strategy for inhibiting cancer metastasis.

Crystal structures, DNA interaction and growth inhibitory activities of the cobalt(II) and nickel(II) complexes of 2-aminothiazole with demethylcantharate

Two new mixed-ligand complexes [M(atz)(DCA)(H2O)2]·2H2O, (M=Co(II), Ni(II); atz=2-aminothiazole, C3H4N2S; DCA2−=demethylcantharate, 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylate, C8H8O5) were prepared and characterized by elemental analysis, infrared spectra and thermogravimetric analysis. The structures of the complexes were determined by X-ray diffraction. The crystals have empirical formulas CoC11H20N2O9S (1) and NiC11H20N2O9S (2), respectively. Complexes 1 and 2 are monoclinic systems with space group P21/m. The structures of the complexes assume severely distorted octahedral geometries. The DNA binding properties of the complexes were investigated by fluorescence quenching studies and viscosity measurements. For the complexes quenching the fluorescence of EB–DNA system, Stern–Volmer quenching constant Ksq values are 0.58 (1) and 1.38 (2), and the interaction modes between the complexes and DNA are partial intercalation. They have moderate activities against human hepatoma cell lines (SMMC7721) and human gastric carcinoma cell lines (MGC80-3) in vitro.

Growth inhibitory effect of 4-phenyl butyric acid on human gastric cancer cells is associated with cell cycle arrest

To investigate the growth effects of 4-phenyl butyric acid (PBA) on human gastric carcinoma cells and their mechanisms. Moderately-differentiated human gastric carcinoma SGC-7901 and lowly-differentiated MGC-803 cells were treated with 5, 10, 20, 40, and 60 μmol/L PBA for 1-4 d. Cell proliferation was detected using the MTT colorimetric assay. Cell cycle distributions were examined using flow cytometry. The proliferation of gastric carcinoma cells was inhibited by PBA in a dose- and time-dependent fashion. Flow cytometry showed that SGC-7901 cells treated with low concentrations of PBA were arrested at the G₀/G₁ phase, whereas cells treated with high concentrations of PBA were arrested at the G₂/M phase. Although MGC-803 cells treated with low concentrations of PBA were also arrested at the G₀/ G₁ phase, cells treated with high concentrations of PBA were arrested at the S phase. The growth inhibitory effect of PBA on gastric cancer cells is associated with alteration of the cell cycle. For moderately-differentiated gastric cancer cells, the cell cycle was arrested at the G₀ /G₁ and G₂/M phases. For lowly-differentiated gastric cancer cells, the cell cycle was arrested at the G₀/G₁ and S phases.

Chemotherapeutic Candidate Inducing Immunological Death of Human Tumor Cell Lines

The immunological death induction by EY-6 on the human tumor cell lines was screened. Human colon carcinoma (HCT15, HCT116), gastric carcinoma (MKN74, SNU668), and myeloma (KMS20, KMS26, KMS34) cells were died by EY-6 treatment with dose-dependent manner. CRT expression, a typical marker for the immunological death, was increased on the EY-6-treated colorectal and gastric cancer cells. Interestingly, the effects on the myeloma cell lines were complicated showing cell line dependent differential modulation. Cytokine secretion from the EY-6 treated tumor cells were dose and cell-dependent. IFN-γ and IL-12 secretion was increased in the treated cells (200% to over 1000% of non-treated control), except HCT116, SNU668 and KMS26 cells which their secretion was declined by EY-6. Data suggest the potential of EY-6 as a new type of immuno-chemotherapeutics inducing tumor-specific cell death. Further studies are planned to confirm the efficacy of EY-6 including in vivo study.