Proton Pump Inhibitors Induce Cell Cycle Arrest and Enhance Chemosensitivity of Gastric Cancer Cells by Inhibiting Cell Cycle-related Genes / 胃肠病学

Background: Several studies have shown that proton pump inhibitors (PPIs) can enhance the sensitivity of gastric cancer (GC) cells to chemotherapy and inhibit tumor proliferation and invasion. Aims: To investigate whether PPI could enhance chemosensitivity by inhibition of cell cycle-related genes in GC cells. Methods: Two human GC cell lines, AGS and HGC27 were treated with pantoprazole in different concentrations, and the cell viability was detected by CCK-8 assay. Transcriptome sequencing combined with KEGG enrichment analysis were used to determine the effect of PPI on cell cycle of GC cells, and the changes of cell cycle and its related genes were validated by flow cytometry, real-time PCR and Western blotting, respectively. Bioinformatics websites were employed to analyze the major differentially expressed cell cycle-related genes in GCs and their relationship with patients' prognosis. After transfection with FOXM1 plasmid or control plasmid, the inhibitory effect of PPI combined with cisplatin on GC cells was determined by CCK-8 assay. Results: PPI inhibited the proliferation of GC cells effectively in vitro. Transcriptome sequencing showed that the expression levels of G2/M phase-related genes, including FOXM1, PLK1, and AURKB were down-regulated in PPI-treated GC cells, and G2/M arrest was suggested by KEGG enrichment analysis. All these changes were proved by flow cytometry, real-time PCR and Western blotting. Bioinformatics analysis revealed that FOXM1, PLK1, and AURKB genes were highly expressed in GCs and correlated with a poor prognosis. The inhibitory effect of PPI combined with cisplatin on GC cells was superior to that of cisplatin alone, but could be partially reversed by overexpression of FOXM1. Conclusions: PPI treatment can induce G2/M arrest in GC cells by inhibiting cell cycle-related genes, and subsequently enhance the sensitivity of GC cells to chemotherapy.

Study on apoptosis mechanism of leukemia cells induced by bisindolylmaleimide derivative L6 / 中草药

Objective: To investigate the effect of bisindolylmaleimide derivative L6 on inducing apoptosis of leukemia cells and its molecular mechanism. Methods: MTT assay was used to determinate the killing effect of L6 on HELL, K562, and KG1a cells. Flow cytometry was used to detect the effects of L6 on apoptosis, cell cycle, and differentiation of HEL cells. Western blotting was used to detect the expression of apoptosis-related protein. Finally, the effect of L6 on leukemia mouse was studied in vivo. Results: MTT assay showed that L6 had a stronger inhibitory activity against HEL, K562, and KG1a cell lines than the positive control PKC412 compound, with IC50 of (0.05 ± 0.03), (0.32 ± 0.01), and (0.19 ± 0.10) μmol/L, respectively. L6 could induce the apoptosis, G2/M arrest, megakaryocyte differentiation of HEL cells with a dose effect. Western blotting revealed that L6 mainly performed apoptosis by activating Caspase-3, which is an apoptotic executive protein. Hematoxylin-eosin (HE) staining of liver tissue of mice showed a reduction in HEL cell infiltration, but the more significant reduction in group L6 was observed, indicating that L6 could delay the metastasis of leukemia, and its effect was better than that of PKC412. Conclusion: Bisindolylmaleimide derivative L6 has a strong anti-leukemia activity, providing new hope for the development of new leukemia drugs.

Effect of Marsdenia tenacissima extract on G2/M cell cycle arrest by upregulating 14-3-3σ and downregulating c-myc in vitro and in vivo / 中草药·英文版

Objective: Marsdenia tenacissima extract (MTE) is a traditional Chinese herbal medicine with anti-cancer activity. In some previous studies, different mechanism actions of the anti-cancer effect of MTE have been revealed. In this study, we first observed that MTE exhibited G2/M cell cycle arrest on two different human breast cancer cell lines, MDA-MB-231 and MCF-7 by mediating 14-3-3σ and c-myc. Methods: The effect of MTE on G2/M cell cycle arrest was evaluated in MDA-MB-231 and MCF-7 cell lines. MTT assay was done for evaluation of cell viability. Flow cytometry was employed for cell cycle analysis. Western blotting analysis and immunohistochemistry were performed to analyze the expression of G2/M cell cycle-related key protein in cells and tissue samples. Animal studies have been conducted to elucidate the anti-tumor effect of MTE. Results: Cell cycle is the backbone for developing cancer. Cell cycle proteins play a major role in the progression of cell cycle and cell proliferation. However, some key protein directly or indirectly modulate the action of cell cycle protein that highly affect cell cycle regulation. In order to investigate cellular proliferation of cancer, we observed that MTE induced the upregulation of 14-3-3σ and downregulation of c-myc, and then reduced the expression of G2/M cell cycle associated key protein, leading to the inhibition of cellular entry into mitosis phase. We also confirmed that MTE exerted a significant antitumor effect on the MDA-MB-231 xenograft model in vivo. Conclusion: G2/M cell cycle arrest occurred by the action of MTE, mediated by the upregulation of 14-3-3σ as well as downregulation of c-myc in MDA-MB-231 and MCF-7 cell lines.

Apoptosis of Human Hepatoma Cell Line SMMC-7721 Induced by Dihydroartemisinin and Its Possible Mechanism / 中国药学杂志

OBJECTIVE: To investigate the apoptosis effect of human hepatocellular carcinoma cell line SMMC-7721 induced by dihydroartemisinin in vitro and the possible mechanism. METHODS: After treatment with 25, 50, 100, 200, and 400 μmol•L-1 dihydroartemisinin for 24 h. The proliferation inhibitory effect of dihydroartemisinin on SMMC-7721 cell was detected by MTT assay. Cell cycle and apoptosis were detected by flow cytometry. The change of apoptotic morphology was detected by confocal laser scanning microscopy. Rho 123 staining method was used to detect the changes of mitochondrial membrane potential. Western blot was used to detect expression of Bcl-2, Bax, Cleaved Caspase-3, Cleaved Caspase-9 and Cyto C. RESULTS: MTT results showed that 25-400 μmol•L -1 dihydroartemisinin can inhibit the proliferation of SMMC-7721 cells obviously. The cell cycle detection results of flow cytometry showed that dihydroartemisinin could block SMMC-7721 cell cycle in G2/M phase. The results of Hochest 333258 staining showed that the nuclei were heterogeneous, condensed and fragmented in the DHA treatment group. The cell apoptosis detection results of flow cytometry showed that the apoptosis rate of dihydroartemisinin treated groups were increased obviously (P < 0.01). The results of Rho 123 staining showed that the mitochondrial membrane potential was decreased significantly (P < 0.01). Western blot results showed that the expression of Bcl-2 was down-regulated, expression of Bax was up-regulated, the ration of Bax /Bcl-2 was increased and the expression of Cleaved Caspase-3, Cleaved Caspase-9 and Cyto C were up-regulated. CONCLUSION: Dihydroartemisinin can induce apoptosis of SMMC-7721 cells, on the mechanism of apoptosis may be related to mitochondrial pathway.

FS-108, an Hsp90 inhibitor,impairs survival and motility of oncogene addicted cancer cells / 中国药理学通报

Aim To investigate the anti-tumor effects of FS-108 an Hsp90 inhibitor, on oncogene addicted EBC-1 and A375 cells. Methods SRB assay was performed to investigate cell proliferation. Immunoblot was conducted to investigate the specific proteins. FACS was conducted to test cell cycle distribution and apoptosis. Transwell assay was conducted to investigate cell motility. Results FS-108 significantly suppressed cell proliferation of EBC-1 and A375 cancer cells with IC50 at 25. 53 nmol · L-1 and 30. 02 nmol · L-1 re-spectively. FS-108 treatment triggered the degradation of key client proteins such as c-Met and B-Raf and thereby reduced their downstream AKT and ERK signa-ling pathways. The FACS analysis results demonstrated that FS-108 treatment induced G2/M phase arrest and apoptosis significantly. Furthermore, FS-108 inhibited the migration of EBC-1 and A375 cells. Conclusion As a potent Hsp90 inhibitor, FS-108 can inhibit onco-gene addicted cancer cells proliferation through induc-tion of G2/M phase arrest and apoptosis.

Smilax china L. rhizome extract inhibits nuclear factor-κB and induces apoptosis in ovarian cancer cells / 中国结合医学杂志

<p><b>OBJECTIVE</b>To study the antitumor effects and associated mechanisms of extract of the Smilax china L. rhizome (SCR) on ovarian cancer cells.</p><p><b>METHODS</b>Ovarian cancer cells A2780 were treated with different concentrations of SCR extract (SCRE), and compared with controls. Effects on cell growth were evaluated by cell counting kit-8 (CCK-8) assay; proliferation effects by EdU incorporation assay; cell cycle by propidium iodide staining; apoptosis by annexin V-fluorescein isothiocyanate/propidium iodide; cellular distribution of nuclear factor-κB (NF-κB) by immunofluorescence; protein levels of NF-κB, caspase-3, poly-adenosine diphosphate (ADP)-ribose polymerase (PARP), Bcl-2-associated X protein (Bax), cellular inhibitor of apoptosis (cIAP)-1, anti-X-linked inhibitor of apoptosis protein (XIAP), B-cell lymphoma-extra large (Bcl-XL), B-cell lymphoma-2 (Bcl-2) and AKT by Western blotting; and effects of SCRE combined with cisplatin or adriamycin on A2780 cells by CCK-8 assay.</p><p><b>RESULTS</b>SCRE suppressed A2780 cell proliferation in a dose-dependent manner (P<0.05,P<0.01), arrested cells in G2/M phase and induced apoptosis by activating caspase-3, PARP and Bax. SCRE treatment also correlated with inhibition of NF-κB and downregulation of Bcl-2, Bcl-XL, cIAP-1, XIAP and AKT. SCRE can promote chemosensitivity to cisplatin and adriamycin in A2780 cells (P<0.01).</p><p><b>CONCLUSION</b>SCR effectively inhibits NF-κB, induces apoptosis and reduces chemoresistance to cisplatin and adriamycin in ovarian cancer cells, which might be its molecular basis for treating ovarian cancer.</p>

DADS induces G2/M arrest through Chk1/Cdc25C/CyclinB1/CDK1 pathway in human leukemia HL-60 cells / 中国药理学通报

Aim To study the effects of cycle arrest and molecular mechanism in human leukemia HL-60 cells induced by diallyl disulfide ( DADS ) . Methods Cell count, colony formation in soft agar experiments and flow cytometry analysis were employed to observe the DADS-induced cell growth inhibition and the effect of cycle arrest in HL-60 cells. The expressions of Chk1/2 and its downstream element in HL-60 cells were detected by Western blot. Results Cell count revealed that population doubling time increased to 35. 03 h and 71. 82 h, respectively, from 19. 14 h in HL-60 cells treated with 60 and 120 μmol·L-1 DADS ( P0. 05). The expression of Cdc25C, CyclinB1 and CDK1 decreased after treated with 60 μmol·L-1 DADS in a time-dependent manner ( P0. 05 ) . Conclusion DADS can in-hibit the proliferation of HL-60 cells, and induce G2/M arrest through Chk1/Cdc25 C/CyclinB1/CDK1 path-way.

UHRF1 expression inhibition by RNA interference enhances the radiosensitivity of esophageal cancer cells / 中华放射肿瘤学杂志

Objective To study the effect of UHRF1 expression inhibition by RNA interference on the radiosensitivity of esophageal cancer cell line TE-1 and its mechanism.Methods Short hairpin RNA (shRNA) targeting UHRF1 gene was introduced into TE-1 cells by lentivector-mediated transfer.The cells were divided into three groups:non-transfected group,negative control (NC)-shRNA-transfected group,and UHRF1-shRNA-transfected group.The mRNA and protein expression levels of UHRF1 in TE-1 cells were measured by RT-PCR and Western blot before and after transfection.After transfection and X-ray radiation,the radiosensitivity of TE-1 cells was evaluated by colony formation assay; the cell cycle and cell apoptosis were determined by flow cytometry; the γ-H2AX (as a marker of DNA damage) level was measured by Western blot.Results After transfection with UHRF1-shRNA,the mRNA and protein expression levels of UHRF1 were significantly decreased in TE-1 cells,as compared with those in the NC-shRNA-transfected group and non-transfected group (0.11 vs 0.96 and 0.98,F =124.21,P =0.000;0.10 vs 0.89 and 0.94,F =125.25,P =0.000).The UHRF1-shRNA-transfected group had sensitization enhancement ratios of 1.53 (D0 ratio) and 1.95 (Dq ratio).X-ray radiation could cause G2/M arrest and increase apoptotic rate and γ-H2AX expression in TE-1 cells.Compared with the two control groups,the UHRF1-shRNA-transfected group showed significantly less G2/M arrest (F =500.15,P =0.000),a significantly higher apoptotic rate (F =100.10,P =0.000),and significantly higher residual γ-H2AX expression (F =61.00,P =0.000) at 24 hours after X-ray radiation.Conclusions RNA interference can effectively inhibit the UHRF1 expression and enhance the radiosensitivity of TE-1 cells.The mechanism may be related to cell cycle regulation,cell apoptosis,and DNA damage repair.

The inhibition effect of continuous low dose rate radiation by 125I radioactive seeds on Hep-2 larynx cancer cell line / 中华放射医学与防护杂志

Objective To investigate the inhibition effect of continuous low dose rate radiation by 125Ⅰ radioactive seeds on Hep-2 cells and the corresponding mechanisms.Methods Hep-2 cells were divided into three groups,control group,single dose radiation group with high dose rate form X-rays (SDR) and continuous low dose rate radiation by 125Ⅰ seeds group (125Ⅰ-CLDR).After exposure to SDR and 125Ⅰ-CLDR,colony formation assay was used to determine the radiosensitivity and RBE,trypan blue exclusion assay was used to determine cell proliferation,and flow cytometry was used to detect cell apoptosis and cell cycle arrest.Results The radiosensitivity of Hep-2 cells to 125Ⅰ-CLDR was higher than that to SDR.The RBE of 125Ⅰ-CLDR versus SDR was approximately 1.61.The α/β ratio of 125Ⅰ-CLDR group was higher than that of SDR group.Both SDR and 125Ⅰ-CLDR inhibited cell proliferation (t =30.9,40.7,P＜0.05),in which 125Ⅰ-CLDR was stronger than SDR (t =9.8,P＜0.05).In addition,the incidences of apoptosis and G2/M arrest induced by125Ⅰ-CLDR were also stronger than those induced by SDR (t =5.8,19.8,P ＜ 0.05).Conclusions 125Ⅰ-CLDR generates more serious inhibition effects than SDR on reducing cellular DNA repair capacity,inducing cell apoptosis and G2/M arrest and inhibiting proliferation of Hep-2 cells.

Inhibition of viral protein r on human colorectal cancer cells and the possible mechanisms / 中华消化外科杂志

Objective To investigate the inhibitive effects of viral protein r (Vpr) of human immunodeficiency virus 1 ( HIV-1 ) on human colorectal cancer cell line HCT-8,and to find the possible mechanisms.Methods The HCT-8 cells were divided into the control group,adv group and adv-Vpr group.HCT-8 cells were not treated in the control group; HCT-8 cells were treated with Adv or Adv-Vpr at different multiplicity of infection (MOI) in the Adv group or Adv-Vpr group,respectively.Cell proliferation was detected by MTT assay.Cell cycle,apoptosis and mitochondrial membrane potential were detected by flow cytometry.The expression of apoptosisrelated proteins was detected by Western blot.All data were analyzed by using the q test,t test and one-way or two-way analysis of variance.Results The proliferation of HCT-8 cells was significantly inhibited by Vpr.The MTT value of HCT- 8 cells in the Adv-Vpr group was 1.03 ± 0.04,which was significantly lower than 2.46 ± 0.15 in the Adv group and 2.51 ± 0.14 in the control group at 72 hours after Adv-Vpr transfection ( MOI =200) ( F =144.6,P ＜ 0.05).The ratio of HCT-8 cells in the G2/M phase was 37.31％ ± 5.90％ in the Adv-Vpr group,which was significantly higher than 18.30％ ± 6.04％ in the Adv group and 16.66％ ± 3.51％ in the control group ( F =10.08,P ＜ 0.05 ).The ratio of HCT-8 cells with decreased mitochondrial membrane potential was 32.07％ ±5.64％ in the Adv-Vpr group,which was significantly higher than 3.32％ ±0.79％ in the Adv group and 2.76％ ±1.43 ％ in the control group at 48 hours after Adv-Vpr transfection ( MOI =200) ( F =64.45,P ＜ 0.05).The apoptosis rate of HCT-8 cells was 37.62％ ±6.48％ in the Adv-Vpr group,which was significantly higher than 3.44％ ± 1.11％ in the Adv group and 2.93％ ± 1.07％ in the control group at 72 hours after Adv-Vpr transfection ( MOI =200) ( F =122.4,P ＜ 0.05 ).The results of Western blot showed that Vpr induced cleavage and activation of Caspase-9 and Caspase-3 and phosphorylation of Chk1-S345,while the expression levels of Fas,Fas-L,ERK1,ERK2 remained the same at 48 hours after Adv-Vpr treatment ( MOI =200).Conclusions Vpr inhibits the proliferation of the HCT-8 cells in vitro through G2/M phase arrest and apoptosis.Vpr plays its role by activating DNA damaging pathway and initiating mitochondria apoptotic pathway.Vpr is a potential therapeutic agent for colorectal cancer.

Growth inhibitory effect and Chk1-dependent signaling involved in G2/M arrest on human gastric cancer cells induced by diallyl disulfide

Diallyl disulfide (DADS) inhibits growth and induces cell cycle G2/M arrest in human gastric cancer MGC803 cells. In this study, 15 mg/L DADS exerted similar effects on growth and cell cycle arrest in human gastric cancer BGC823 cells. Due to the importance of cell cycle redistribution in DADS-mediated anti-carcinogenic effects, we investigated the role of checkpoint kinases (Chk1 and Chk2) during DADS-induced cell cycle arrest. We hypothesized that DADS could mediate G2/M phase arrest through either Chk1 or Chk2 signal transduction pathways. We demonstrated that DADS induced the accumulation of phosphorylated Chk1, but not of Chk2, and that DADS down-regulated Cdc25C and cyclin B1. The expression of mRNA and total protein for Chkl and Chk2 was unchanged. Chk1 is specifically phosphorylated by ATR (ATM-RAD3-related gene). Western blot analysis showed that phospho-ATR was activated by DADS. Taken together, these data suggest that cell cycle G2/M arrest, which was associated with accumulation of the phosphorylated forms of Chk1, but not of Chk2, was involved in the growth inhibition induced by DADS in the human gastric cancer cell line BGC823. Furthermore, the DADS-induced G2/M checkpoint response is mediated by Chk1 signaling through ATR/Chk1/Cdc25C/cyclin B1, and is independent of Chk2.

ASPS induces G_2/M arrest of H446 cells by activation of ERK signal pathway / 基础医学与临床

Objective To investigate ASPS induced G_2/M arrest in lung cancer cell line H446 and its effect on ERK MAP kinase signal transduction pathways. Methods Cell cycle phases were inspected by flow cytometery (FCM) ; Western blot analysis was used to inspect the proteins of ERK, p-ERK. Results Compared with control group, G_2/M phase cells increased with concentration significantly, G_0/G_1 phase cells were not different, G_2/M phase cells and G_0/G_1 phase cells were not different when pre-incubated with PD98059 prior to exposure to ASPS of different concentrations, protein of p-ERK was significantly increased, expression of ERK was no different. Conclusion ASPS may induce G_2/M arrest of H446 cells possibly by activation ERK MAP kinase pathways.

RNA Silencing Suppressor p19 Regulates The Expressions of Cell Cycle Related Genes / 生物化学与生物物理进展

Besides its function as a pathogenicity determinant, the Tombusvirus P19 also serves as a suppressor of RNA interference (RNAi) by sequestering intracellular small RNAs such as the small interfering RNAs (siRNAs) and microRNAs (miRNAs). However, the effect of P19 on mammalian cells has not been evaluated before. A human embryonic kidney 293 cell line that stably expressed p19 (HEK293-p19) was generated. Flow cytometric analysis revealed that over-expression of P19 caused a significant accumulation of G2/M phase cells. Cell proliferation assays demonstrated a reduced DNA replication and cell growth in HEK293-p19 cells. Moreover, p19 altered the expression profiles of a number of cell cycle regulators in HEK293 cells, such as upregulafion of cyclin A1, CDK2, CDK4, CDK6, p18, cyclin D2, p19INK4d and E2F1, and downregulation of p15, cyclin A2, cyclin B1 and cyclin E1. Thus, the data strongly indicate that p19 might influence multiple G2/M regulators to cause G2/M arrest.

Dual effect of Molt-4 cell lines onset with Roscovitine / 肿瘤研究与临床

Objective To investigate the effect of Mlot-4 cells onset with Roscovitine (ROSC)as some Cyclin-dependent kinases(CDK),inhibitor.Methods The logarithmic growth phase Molt-4 cells treated with ROSC at a final concentration ranging between 1～20 μmol/L and harvested in different time point,DNA assay of single cells by flow cytometry was used to detect the effect of cell cycle arrest and Annexin-V/FITC assay was used to detect the effect of cell apoptosis. Results It showed that ROSC exerted strong inhibitory effect on proliferation and cell cycle progression of Molt-4 Accumulation of G2/M arrested cells starting 6 h after onset of 10 μmol/L and 20 μmol/L ROSC;at the same time,the cell apoptosis of Molt-4 would be detected,According with the time and concentration changing,the cell apoptosis rate would rise.Conclusion It is concluded that Roscovitine(ROSC)as some Cyclin-dependent kinases(CDK),inhibitor,It has dual effects to Molt-4 cells,not only the effect of cell cycle arrest but also the effect of cell apoptosis.

Effects of pervanadate on radiation-induced G2/M arrest and apoptosis in BET-2 cells / 肿瘤研究与临床

Objective To study the effects of Pervanadate(Per) on BET-2 cells cell cycle arrest and apoptosis induced by ionizing radiation. Methods The BET-2 cells were radiated with 0, 1, 3, 5, 7, 10 Gy and divided into PTP(protein tyrosine phosphatases)-specific inhibitor Per-treated group and non-pervanadate group(served as a control) and then incubated after ?-ray irradiation. Cell cycle and apoptosis were measured by FCM and Hematoxylin-Eosin staining at different time phases. Results G2/M phase arrest and apoptosis were induced in a pattern of dose-effect and time-course after irradiation in the BET-2 cells. In Per-treated group, G2/M phase arrest increased more notably, and apoptosis decreased markedly. Conclusions These studies suggested that Pervanadate potentialy enhance the ratio and prolong the term of G2/M phase arrest, and facilitate the damaged hematopoietic cells to be repaired, remarkably prevent radiated-cells from apoptosis.

A Histone Deacetylase Inhibitor, Trichostatin A, Enhances Radiosensitivity by Abrogating G2/M Arrest in Human Carcinoma Cells / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Histone deacetylase inhibitors (HDIs) are emerging as potentially useful components in anticancer therapy. In this study, we tried to confirm the radiosensitizing effect of trichostatin A (TSA) on a panel of human carcinoma cell lines and elucidate its mechanism of interaction. MATERIALS AND METHODS: A549, HeLa and Caski cells were exposed to TSA for 18 hr prior to irradiation, and the cell survival then measured using a clonogenic assay. Western blot and flow cytometric analyses, for histone acetylation, and cell cycle and apoptosis, respectively, were also performed. RESULTS: TSA increased the acetylation of histone H3. The pretreatment of TSA consistently radiosensitized all three cell lines. The SF2 (surviving fraction at 2 Gy) of TSA-treated cells was significantly lower than that of mock treated cells. The SER (sensitizer enhancement ratio) increased in all 3 cell lines, in concentration dependent manners. The TSA treated cells showed abrogation of radiation-induced G2/M arrest, in a concentration dependent manner. CONCLUSION: The pretreatment of TSA enhanced the radiosensitivity of a panel of human carcinoma cells, which was attributed, in part, to the abrogation of radiationinduced G2/M arrest.

STUDY ON THE INHIBITED PROLIFERATION AND G_2/M ARREST OF HUMAN GASTRIC CARCINOMA CELLS INDUCED BY GENISTEIN IN VITRO / 营养学报

Objective: To study the effects of genistein on the proliferation and cell cycle progression of human gastric carcinoma cells. Methods: 3H TdR incorporation test was used to investigate the cell proliferation. Flow cytometry was used to analyze the cell cycle arrest. Immunocytochemistry technique and Western blotting were used to observe the cyclin B and P21 waf1/cip1 protein expression. Results: Genistein inhibited the proliferation of tumor cells significantly, arrested cell cycle progression at G 2/M phase, and enhanced cyclin B and P21 waf1/cip1 protein expression in dose dependent manner. Conclusion:Proliferatory inhibition and G 2/M arrest of human gastric carcinoma cells after treated with genistein may be due to increased stability of cyclin B protein and the expression of P21 waf1/cip1 .