Diallyl disulfide augments sensitivity of DJ-1 overexpressed human gastric cells to 5-FU / 中国药理学通报

Aim To investigate whether diallyl disul-fide (DADS) augments the sensitivity of DJ-1 (protein/ nucleic acid deglycase) overexpressed human gastric SGC7901 cells to 5-FU (5-fluorouracil). Methods The experimental groups include control group, DADS group, VCR (vincristine) group, VCR + DADS group, DJ-1 group, DJ-1 + DADS group. MTT was used to analyze the effect of DADS on 5 -FU (5 -fluorou- racil) induced proliferation inhibition. Flow cytometry was performed to examine the effect of DADS on cell apoptosis. RT-PCR, Western blot, and immunofluo-rescence were used for determine the effect of DADS on the drug resistance associated gene expression. Results DADS enhanced the proliferation inhibitory effect of 5-FU on DJ-1 overexpressed cells and VCR resistant cells. DADS could induce apoptosis in VCR-resistant cells. DADS downregulated the expression of DJ-1 while inducing apoptosis in DJ-1 overexpressed cells. DJ-1 overexpression upregulated the expression of P-gp (P-glycoprotein), Bcl-2, and XIAP (X-linked inhibitor of apoptosis protein), downregulated the expression of caspase-3. DADS decreased the expression of P-gp, Bcl-2, and XIAP, while increased the expression of caspase-3 in DJ-1 overexpressed cells and VCR-resistant cells. Conclusions DADS can augment the sensitivity of DJ-1 overexpressed cells to 5-FU, which is related to its antagonism against DJ-1 mediated upregula- tion of P-gp, Bcl-2, XIAP, and downregulation of caspase-3.

Inhibition of liver glutaminase activity by Diallyl disulfide in experimentally induced hepatoma in mice

Background: Cancer cells addiction to glutamine, an essential non-essential amino acid, has stirred up the interest in researchers across the globe. Increased glutamine metabolism (glutaminolysis) is a hallmark of cancer. Targeting glutaminolysis via glutaminase inhibition emerges as a promising strategy to disrupt cancer metabolism and tumor progression. Diallyl disulfide (DADS), a major organosulfur compound derived from garlic, is known for its anticancer properties. The mechanisms of action of DADS include activation of metabolic enzymes that detoxify carcinogens, suppression of the formation of DNA adducts, antioxidant effects, regulation of cell-cycle progression, induction of apoptosis, and inhibition of angiogenesis and metastasis. Aim: to assess the effect of diallyl disulfide on liver glutaminase activity in experimentally induced hepatoma in mice. Materials & Methods: Swiss albino male mice were divided into four groups - normal, control, preventive and curative groups. Hepatoma was induced by intraperitoneal injection of Ehrlich ascites carcinoma (EAC) cells. DADS (100 mg/kg body weight/mouse/day) was orally fed to protective and curative group mice for a stipulated time period. Mice of all the groups were sacrificed, and liver tissue glutaminase activity were measured. Results: The present study shows a significant decrease in glutaminase activity in protective (p >0.001) and curative groups (p >0.001) as compared to control group. Conclusion: DADS at the dosage employed shows inhibitory effects on liver glutaminase activity which may be attributed to anti-inflammatory properties of DADS, specifically in suppression of NF-kB signalling pathway.

Effect of diallyl disulfide on liver nucleotide metabolism in experimentally induced hepatoma in mice.

Background: The antitumorigenic effects of active ingredient of garlic, diallyl disulfide (DADS), has been extensively studied & found to retard the growth of neoplastic cells than any other allyl sulfur compounds of garlic. Earlier we have reported antitomorogenic properties of DADS, showing tumor regression by interfering with the liver glucose utilization, protein synthesis as well as lipid synthesis in tumor cells. Aim: To assess the effect of diallyl disulfide on liver nucleotide metabolism in experimentally induced hepatoma in mice. Materials & Methods: Swiss albino male mice were divided into four groups - normal, control, preventive and curative groups. Hepatoma was induced by intraperitoneal injection of Ehrlich ascites carcinoma (EAC) cells. DADS (100 mg/kg body weight/mouse/day) was orally fed to protective and curative group mice for a stipulated time period. Mice of all the groups were sacrificed, and liver tissue adenosine deaminase (ADA) activity and uric acid (UA) levels were measured. Results: The present study shows a significant decrease in ADA activity and UA levels in protective (p >0.001) and curative groups (p >0.01) as compared to control group. Conclusion: DADS has inhibitory effects on nucleotide metabolism by inhibiting the activities of ADA and xanthine oxidase enzymes, and by reducing the production of deoxy ribonucleotides, probably by involving in thiol-disulfide exchange reactions.

Diallyl disulfide and diallyl trisulfide in garlic as novel therapeutic agents to overcome drug resistance in breast cancer / 药物分析学报

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide.It is a cancer that originates from the mammary ducts and involves mutations in multiple genes.Recently,the treatment of breast cancer has become increasingly challenging owing to the increase in tumor het-erogeneity and aggressiveness,which gives rise to therapeutic resistance.Epidemiological,population-based,and hospital-based case-control studies have demonstrated an association between high intake of certain Allium vegetables and a reduced risk in the development of breast cancer.Diallyl disulfide(DADS)and diallyl trisulfide(DATS)are the main allyl sulfur compounds present in garlic,and are known to exhibit anticancer activity as they interfere with breast cancer cell proliferation,tumor metastasis,and angiogenesis.The present review highlights multidrug resistance mechanisms and their signaling pathways in breast cancer.This review discusses the potential anticancer activities of DADS and DATS,with emphasis on drug resistance in triple-negative breast cancer(TNBC).Understanding the anticancer activities of DADS and DATS provides insights into their potential in targeting drug resistance mecha-nisms of TNBC,especially in clinical studies.

Diallyl disulfide downregulates XIAP through miR-7 to inhibit proliferation, migration and invasion of human gastric cancer SGC7901 cells / 中国药理学通报

Aim To investigate whether diallyl disul¬fide ( DADS) downregulates X-linked inhibitor of ap- optosis protein ( XIAP) through miR-7 , inhibiting the proliferation, migration anrl invasion of gastric eaneer SGC7901 eel Is.Methods Gastric eaneer SGC7901 eell line overexpressing XIAP was established.qRT- PCR and Western blot were used to deteet the effeet of DADS on XIAP expression in overexpressed eells.CCK-8 and plate elone formation assay were used to analyze the effeet of DADS on the proliferation of XIAP overexpressing eells.Wound healing and Transwell ex¬periments were employed to analyze the effeets of DADS on the migration and invasion of XIAP overex¬pressing eells.qRT-PCR was used to deteet the effeet of DADS on the expression of miR-7.Negative regula¬ tion of miR-7 on XIAP was verified by using dual lucif- erase reporter gene assay, qRT-PCR ,anrl Western blot.Results XIAP overexpression enhanced the prolifera¬tion , migration and invasion of SGC7901 cells.DADS downregulated XIAP and inhibited the proliferation, mi¬gration and invasion of XIAP overexpressing cells.DADS upregulated miR-7 expression.miR-7 bound and regulated XIAP 3 'UTR directly.Overexpression of miR-7 decreased XIAP expression,while knockdown of miR-7 increased XIAP expression.Conclusion DADS downregulates XIAP through miR-7 to inhibit SGC7901 cell proliferation, migration and invasion.

The differential expression of microRNA in human gastric cancer MGC803 cells induced by diallyl disulfide / 中国药理学通报

Aim: To investigate the expression and i-dentification of differential miRNAs in human gastric cancer MGC803 cells induced by diallyl disulfide (DADS). Methods: Differential miRNAs expression in human gastric cancer MGC803 cells induced by DADS was detected and identified by miRNA chip and qPCR. Results: MiRNAs chip detection showed upregulation of miR-200b, miR-22, miR-7, miR-143, miR-138, miR-34a and miR-150, and down-regulation of miR-222, miR-21, miR-15b, miR-182 and miR-18a in differential miRNAs of MGC803 cells treated with 3 0 mg · IT-1 DADS at 24 h(P<0.05). And qPCR demonstrated that the expressions of miR-200b, miR-22, miR-7, miR-143, miR-138, miR-34a and miR-150 was up-regulated in MGC803 cells treated with 30 mg · L-1 DADS(P <0. 05). Moreover, qPCR showed that the expressions of miR-200b and miR-22 in various human gastric cancer cells including MGC803, BGC823, MKN28, SGC7901 and HGC27 cells were lower than normal human gastric cancer GES-1 cells (P <0. 05). The expression of miR-200b and miR-22 in gastric cancer tissues was significantly lower than that in normal gastric tissues (P < 0. 05). Conclusions: The expression of down-regulation of 7 miRNA and up-regulation of 5 miRNA in differential miRNAs in MGC803 cells induced by DADS. The expression of down-regulation of miR-200b and miR-22 in gastric cancer tissues and cells. DADS could up-regulate the expression of miR-200b and miR-22 in gastric cancer cells.

Protective effect of diallyl disulfide against the radiation damage in germ cells of male mice / 中国比较医学杂志

Objective To study the radiation-protective effect of diallyl disulfide(DADS)in germ cells of male mice. Methods Male mice were whole-body exposured to 4 Gy X-ray irradiation to establish a animal radiation damage model. Testicular histology, sperm motility and sperm deformity rate were observed, protein carbonyl content, malondialdehyde(MDA)and 8-hydroxy deoxyguanosine(8-OHdG)content were tested to assess the degrees of radiation damages of sperm cells and protective effect of DADS. Testicular tissue antioxidant enzymes such as superoxide dismutase (SOD),catalase(CAT),glutathione peroxidase(GSH-px)activity and glutathione(GSH)content were examined. The expression of Nrf2 signal protein was detected to explore the radiation-protective mechanism of DADS. Results Compared with the pure exposure group, the testicular tissue damages in the DADS pretreatment group were milder, sperm motility increased significantly(P< 0.05)and sperm deformity rate decreased(P< 0.05), and the protein carbonyl content, MDA and 8-OHdG levels significantly reduced(P< 0.05). The antioxidant indexes of SOD, CAT, GSH-px and GSH were markedly improved(P< 0.05),and the expression of Nrf2 was dramatically enhanced. Conclusions DADS has a protective effect on acute radiation injury in germ cells of male mice by means of anti-oxidative ability.

Up-regulation of miR-22 through Wnt pathway suppresses proliferation, migration and invasion in human gastric MGC803 cells by DADS / 中国药理学通报

Aim To investigate the up-regulation of miR-22 through Wnt pathway inhibits the proliferation,migration and invasion in human gastric MGC803 cells induced by diallyl disulfide(DADS).Methods The effects of proliferation,migration,and invasion of gastric cancer cells were evaluated by MTT,wound-healing and invasion assays.Online prediction software was applied to search the target gene of miR-22.Luciferase report gene assay was used to assess the target genes Wnt-1 of miR-22.The expressions of Wnt-1,β-catenin and TCF-4 were tested by qRT-PCR and Western blot,respectively.Results MTT showed that DADS and miR-22 notably decreased the proliferation compared with control group(P<0.05).Wound-healing assay showed that DADS and miR-22 could significantly inhibit the migration of MGC803 cells compared with the control group, especially in miR-22+DADS(P<0.05). Invasion assay showed that DADS and miR-22 could markedly inhibit the invasion of MGC803 cells compared with the control group, especially in miR-22+DADS(P<0.05). Online prediction software to search the target gene exhibited that Wnt-1 may be a target gene of miR-22. Luciferase report gene assay disclosed that Wnt-1 was identified as a direct target of miR-22. Qrt-PCR showed that the expression of Wnt-1 Mrna was respectively down-regulated by DADS and miR-22 compared withcontrol group, especially in miR-22+DADS(P<0.05). Western blot exhibited that DADS and miR-22 obviously suppressed the expressions of Wnt-1, β-catenin and TCF-4 proteins, especially in miR-22+DADS(P<0.05).Conclusion Up-regulation of miR-22 through Wnt pathway can remarkably suppress the proliferation, migration and invasion in MGC803 cells by DADS.

Overexpression of Chk1/2 gene affects G2/M arrest in MGC803 cells induced by diallyl disulfide / 中国药理学通报

Aim To investigate the effects of diallyl di-sulfide( DADS) on G2/M arrest in Chk1/MGC803 and Chk2/MGC803 cells so as to establish stable human gastric cancer MGC803 cells with overexpression of Chk1/2 gene. Methods The colony formation, flow cytometry, RT-PCR and Western blot were used to de-tect the proliferation, cell cycle, and expression of Chk1/2 mRNA and protein, p-Chk1/2, CDC25C and cyclinB1, respectively. Results The colony formation showed that the colony forming efficiency in Chk1/MGC803 and Chk2/MGC803 cells treated by 30 mg· L-1 DADS was lower than in control group and vector group ( P <0. 05 ) . Flow cytometry demonstrated that 41. 3%, 57. 4%, 68. 9% and 42. 9% of G2/M cells in Chk1/MGC803 were increased than in MGC803 and Chk2/MGC803 , respectively after treated by DADS in 12,24, 36 and 48 h(P <0. 05). At the same time, RT-PCR disclosed that expression of Chk1 and Chk2 mRNA had no marked change. Western blot showed that total proteins of Chk1 and Chk2 and p-Chk2 had invisible change, but expression of p-Chk1 was up-reg-ulated, and CDC25C and cyclinB1 were down-regula-ted time-dependently in Chk1/MGC803 cells ( P <0. 05 ) . Conclusion DADS arrests MGC803 cells at G2/M by increasing p-Chk1 expression to cause down-regulation of CDC25C and cyclinB1 simultaneously.

Diallyl disulfide attenuates acetaminophen-induced renal injury in rats / 한국실험동물학회지

This study investigated the protective effects of diallyl disulfide (DADS) against acetaminophen (AAP)-induced acute renal injury in male rats. We also investigated the effects of DADS on kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), which are novel biomarkers of nephrotoxicity in renal tissues, in response to AAP treatment. The following four experimental groups were evaluated: (1) vehicle control, (2) AAP (1,000 mg/kg), (3) AAP&DADS, and (4) DADS (50 mg/kg/day). AAP treatment caused acute kidney injury evidenced by increased serum blood urea nitrogen (BUN) levels and histopathological alterations. Additionally, Western blot and immunohistochemistry analysis showed increased expression of KIM-1 and NGAL proteins in renal tissues of AAP-treated rats. In contrast, DADS pretreatment significantly attenuated the AAP-induced nephrotoxic effects, including serum BUN level and expression of KIM-1 and NGAL proteins. Histopathological studies confirmed the renoprotective effect of DADS. The results suggest that DADS prevents AAP-induced acute nephrotoxicity, and that KIM-1 and NGAL may be useful biomarkers for the detection and monitoring of acute kidney injury associated with AAP exposure.

The Effect of Garlic Derivatives (S-Allylmercaptocysteine, Diallyl Disulfide, and S-Allylcysteine) on Gentamicin Induced Ototoxicity: An Experimental Study

OBJECTIVES: Gentamicin is a potent aminoglycoside antibiotic. Ototoxicity and nephrotoxicity are the main side effects which restrict the use of gentamicin. Garlic with its intrinsic antioxidant activity may prove beneficial in prevention from ototoxicity. S-allylmercaptocysteine (SAMC), diallyl disulfide (DD), and S-allylcysteine (SAC) are three active compounds found in garlic. In this study, we investigated the effect of SAMC, DD, and SAC on the ototoxicity induced by gentamicin in rats, by using brainstem evoked response audiometry (BERA). METHODS: Thirty male Wistar rats with intact Preyer’s reflex initially weighing 220–260 g were randomly assigned to either the gentamicin injection with SAMC treatment group (Genta-w SAMC), DD treatment group (Genta-w DD), SAC treatment group (Genta-w SAC), gentamicin injection without any active compounds (AC) treatment groups (Genta-w/o AC), or control group (n=6 rats each group). Gentamicin was given 120-mg/kg body weight, intraperitoneally once daily for 25 days to subjects in all groups except the control group. SAMC 100-mg/kg, and DD 50-mg/kg body weight were given intragastrically, and SAC 250-mg/kg body weight was given intraperitoneally once daily to subjects in Genta-w SAMC, and Genta-w DD, and Genta-w SAC groups, respectively during the study. After 25 days hearing thresholds were evaluated by using BERA test. RESULTS: The mean amplitude of auditory thresholds (sensation level [SL]) measured by using BERA for the Genta-w SAMC, Genta-w DD, Genta-w SAC, Genta-w/o AC, and control groups were 22±8, 25±5, 30±9, 54±11, and 10±7 dB SL, respectively (mean±SD). The differences between every active compound group (Genta-w SAMC, Genta-w DD, and Genta-w SAC) and Genta-w/o AC were statistically significant (P<0.016). CONCLUSION: SAMC, DD, and SAC are derivative of garlic seems to attenuate aminoglycoside-induced hearing loss. The effect of SAMC and DD seems to be more prominent than that of SAC.

Diallyl Disulfide Prevents Cyclophosphamide-Induced Hemorrhagic Cystitis in Rats through the Inhibition of Oxidative Damage, MAPKs, and NF-kappaB Pathways

This study investigated the possible effects and molecular mechanisms of diallyl disulfide (DADS) against cyclophosphamide (CP)-induced hemorrhagic cystitis (HC) in rats. Inflammation response was assessed by histopathology and serum cytokines levels. We determined the protein expressions of nuclear transcription factor kappa-B (NF-kappaB), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor-alpha (TNF-alpha), oxidative stress, urinary nitrite-nitrate, malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Finally, we studied the involvement of mitogen-activated protein kinases (MAPKs) signaling in the protective effects of DADS against CP-induced HC. CP treatment caused a HC which was evidenced by an increase in histopathological changes, proinflammatory cytokines levels, urinary nitrite-nitrate level, and the protein expression of NF-kappaB, COX-2, iNOS, TNF-alpha, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal regulated kinase (ERK). The significant decreases in glutathione content and glutathione-S-transferase and glutathione reductase activities, and the significant increase in MDA content and urinary MDA and 8-OHdG levels indicated that CP-induced bladder injury was mediated through oxidative DNA damage. In contrast, DADS pretreatment attenuated CP-induced HC, including histopathological lesion, serum cytokines levels, oxidative damage, and urinary oxidative DNA damage. DADS also caused significantly decreased the protein expressions of NF-kappaB, COX-2, iNOS, TNF-alpha, p-JNK, and p-ERK. These results indicate that DADS prevents CP-induced HC and that the protective effects of DADS may be due to its ability to regulate proinflammatory cytokines production by inhibition of NF-kappaB and MAPKs expressions, and its potent anti-oxidative capability through reduction of oxidative DNA damage in the bladder.

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.

Effects of DADS on the xenograft growth of NCI-H446 human small cell lung cancer cells in nude mice / 医学研究生学报

Objective Diallyl disulfide ( DADS) has achieved remarkable effects in treatment and research of diverserfied cancers.The article was to explore the effects and the mechanism of DADS on the xenograft growth of human small cell lung cancer ( SCLC) cells in nude mice . Methods A total of 25 nude mice were selected to establish xenograft model of NCI-H446 human SCLC cells.The nude mice bearing with SCLC H446 were divided into 5 groups by random selection:positive control group(DDP 66 mg/kg), negative control group(physiological saline), 20 mg/kg DADS group, 60 mg/kg DADS group and 180 mg/kg DADS group, which is 40.6%, 53.1%and 66.4%, respectively.The growth of xenograft tumor in mice was observed after being treated with differ-ent concentrations of DADS .The morphological changes of the tumors were examined under light microscopy .Phase distribution and apoptosis of xenograft cells were analyzed by flow cytometry ( FCM) . Results The growth of xenograft tumor were inhibited signifi-cantly by DADS, resulting in decreased cell density and cellular atypia .Moreover, xenograft cell cycle was blocked in G 2/M and cell apoptosis rate was enhanced . Conclusion DADS can significantly inhibit the growth of NCI-H446 cells and lead to apoptosis .

Diallyl disulfide inhibits migration and invasion in human colon cancer SW480 cells through Rac1-ADF/cofilin1 pathway / 中国肿瘤临床

Objective:This work aims to investigate diallyl disulfide (DADS) inhibition of cell migration and invasion in human colon cancer SW480 cells through the Rac1-ADF/cofilin1 pathway. Methods:The potential of cell migration and invasion was examined by scratch healing assay and transwell membrane assay. The expression of Rac1-ADF/cofilin1 pathway was detected by RT-PCR and Western blot. Results:After the SW480 cells were treated with 40 and 50 mg·L-1 of DADS for 24 h, the number of transmembrane cells through the Matrigel obviously decreased by 57.12%and 64.59%, respectively (P0.05). After the treatment with 45 mg·L-1 of DADS for 6, 12, 24, and 48 h, the expression of Rac1, Rock1, PAK1, LIMK1, and Destrin proteins respectively decreased in a time-dependent manner compared with the control group (P0.05). Moreover, the expression of p-LIMK1 and p-cofilin1 notably decreased in a time-dependent manner (P<0.05). Conclusion:DADS inhibits cell migration and invasion, which is related to the down-regulation of Rac1, Rock1, PAK1, LIMK1, p-LIMK1, p-cofilin1, and destrin through the Rac1-ADF/cofilin1 pathway.

Protective effect of diallyl disulfide on cyclophosphamide-induced testicular toxicity in rats / 한국실험동물학회지

This study investigated the protective effects of diallyl disulfide (DADS) against cyclophosphamide (CP)-induced testicular toxicity in male rats. DADS was gavaged to rats once daily for 3 days at 100 mg/kg/day. One hour after the final DADS treatment, the rats were given a single intraperitoneal dose of 150 mg/kg CP. All rats were killed and necropsied on day 56 after CP treatment. Parameters of testicular toxicity included reproductive organ weight, testicular sperm head count, epididymal sperm motility and morphology, epididymal index, and histopathologic examinations. The CP treatment caused a decrease in body weight, testicular sperm head count, epididymal sperm motility, and epididymal index. The histopathological examination revealed various morphological alterations, characterized by degeneration of spermatogonia/spermatocytes, vacuolization, and decreased number of spermatids/spermatocytes in the testis, and cell debris and mild oligospermia in the ductus epididymis. In contrast, DADS pretreatment effectively attenuated the testicular toxicity caused by CP, including decreased sperm head count, epididymal sperm motility, and epididymal index and increased histopathological alterations in the testis and epididymis. These results indicate that DADS attenuates testicular toxicity induced by CP in rats.

Induction of apoptosis with diallyl disulfide in AGS gastric cancer cell line / 대한외과학회지

PURPOSE: Diallyl disulfide (DADS) is a major organosulfur compound derived from garlic. It has been reported that DADS is able to inhibit the proliferation of several tumor cells. In this study, the effect of DADS was investigated in terms of the proliferation of AGS, gastric adenocarcinoma cell line at various concentrations. METHODS: The viability of cultured cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. To detect the induction of apoptosis, Annexin V-FITC/propodium iodide (PI) staining assay was performed. Analysis of reactive oxygen species (ROS) and the distribution of cells in the cell cycle were measured by a flow cytometer. And using the Western blot analysis, the change of Fas, caspase-3, Bax, Bcl-2 activity was measured. RESULTS: The percentage of live AGS cells was decreased to 23% of that in the control group after 400 microM DADS treatment for 48 hours. The Annexin V positive/PI negative (apoptosis portion) area increased from low concentration of DADS to high concentration. When comparing among the DADS treatment groups, the amount of ROS production increased in a dose dependent manner. The percentage of sub-diploid DNA content increased from 8.71% at 50 microM to 25.74% at 400 microM DADS treatment group. The expressions of Fas, caspase-3, Bax were increased and that of Bcl-2 was decreased in a dose dependent manner. CONCLUSION: DADS decreases the viability of AGS cell lines and induces apoptosis in a dose-dependent manner. But the relationship of the anti-proliferative effect of DADS and related molecular changes were not clearly proportional to the concentration of DADS.

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.

Diallyl disulfide induces human leukemia HL-60 cells differentiation by up-regulating the expressions of p21,STAT1 and CAMTA1 / 中国药理学通报

Aim To investigate the molecular mechanisms of differentiation in human leukemia HL-60 cells induced by diallyl disulfide(DADS)using suppression subtractive hybridization(SSH).Methods In our privious study,the subtractive cDNA library was constructed successfully and efficiently. 30 clones were randomly analyed with restriction enzyme.The inserts of cDNAs were analyzed by restrictive enzyme EcoR I.Positive clones were sequenced and the homology of resulting cDNA sequences were analyzed through bioinformatics software Blastn.Results 18 clones contained 100～600 bp cDNA inserts.10 differantiation genes were obtained and involved in cell cycle,signal transduction,metabolism and RNA binding.And 3 of 10 genes,p21,STAT1 and CAMTA1 were up-regulated and detected by RT-PCR,the results matched with SSH.Conclusion sThere are tight correlation between the differentiation induced by DADS and three-upregulated gene:p21,STAT1 and CAMTA1.

Mechanism of Cell Cycle G_2/M Arrest in Human Gastric Cancer BGC823 Cells Induced by Diallyl Disulfide / 中国肿瘤临床

Objective: Cell cycle has recently become more appealing as a new target of anti-carcinogen-ic agent. Diallyl disulfide (DADS) inhibits growth and induces call cycle G_2/M arrest in human gastric cancer BGC823 cells. Cell division cycle protein 25C (Cdc25C) and CyclinB1 expression are involved in G_2/M arrest.However, mechanisms of G_2/M arrest are not yet fully understood. The aim of this study was to elucidate the mechanism of cell cycle G_2/M arrest in human gastric cancer BGC823 cells induced by DADS. Methods: The expression of chk1 and Chk2 mRNA associated with cell cycle arrest of BGC823 cells after the induction with DADS for 1 or 2 days was detected by RT-PCR. The protein expression of cycle-related proteins ATM-RAD3-related gene (ATR), checkpoint kinase1 (Chk1), checkpoint kinase 2 (Chk2), P-ATR, P-Chk1 and P-Chk2 was measured by Western blot. Interaction between Chk1/2 and Cdc25C was analyzed by immuno-precipitation. Results: After the cells were treated with 15 mg/L DADS for 1 or 2 days, the expression of Chk1 and Chk2 mRNA was not significantly different from that in untreated cells (P>0.05). Western blot analysis showed that the expression of total Chk1 and Chk2 treated with 15 mg/L DADS was not significantly different from that in untreated cells. But phospho-chk1 showed a significant increase after stimulation with 15 mg/L DADS for 2h to 12h and continued to increase gradually as time went on (P<0.05). Phospho-Chk2 showed a eak expression and a weaker expression after stimulation with DADS, but the changes were not statistically significant (P>0.05). Addition of 15 mg/L DADS to BGC823 cells for 15 rain to 120 min resulted in an increase in phospho-ATR expression, whereas no changes were found in ATR expression (P<0.05). The Chk1 Ab in-creasingly precipitated Cdc25C in BGC823 cells treated with DADS (P<0.05). In contrast, Chk2 Ab failed to change precipitation with Cdc25C by DADS (P>0.05). Conclusion: Activation of chk1 was involved in cell cy-cle G_2/M arrest in BGC823 cells treated with DADS. Cell cycle G_2/M arrest by DADS is associated with phos-phorylation of several cell cycle regulatory proteins including ATR and Chk1 which regulate expression of Cdc25C.