Chemopreventive effects of curcumin on chemically induced mouse skin carcinogenesis in BK5.insulin-like growth factor-1 transgenic mice

The insulin-like growth factor-1 (IGF-1) signaling pathway is strongly associated with the risk of various cancers, and its inhibition has emerged as a potent anticancer strategy. Accumulating evidence from in vitro studies has shown that curcumin is a potent inhibitor of the IGF-1 signaling pathway. However, direct evidence that curcumin modulates IGF-1-induced tumorigenesis in a physiological system has not been reported. Therefore, in this study, we assessed the anticarcinogenic activity of curcumin on skin cancer by using BK5.IGF-1 transgenic (Tg) mice that overexpress IGF-1 in the skin epidermis. In 7,12-dimethylbenz(a)anthracene (DMBA)-tetradecanoyl phorbol-13-acetate (TPA) two-stage skin carcinogenesis, a curcumin diet (0.02% wt/wt) fed for 14 wk remarkably reduced mouse skin tumor multiplicity by 53%, epidermal hyperplasia and proliferation compared to the control diet group. TPA-induced phosphorylation of Akt, S6 kinase (S6K), and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) in mouse skin was lower in the curcumin group than in the control group. Curcumin treatment inhibited IGF-1-induced phosphorylation of the IGF-1 receptor, insulin receptor substrate-1, Akt, S6K, and 4EBP1 in the mouse keratinocyte cell line, C50 in a dose-dependent manner. Taken together, these data suggest that curcumin exerts significant anticarcinogenic activity in skin cancer through the inhibition of IGF-1 signaling.     

NDRG1 expression is related to the progression and prognosis of gastric cancer patients through modulating proliferation,invasion and cell cycle of gastric cancer cells

N-myc downstream-regulated gene 1 (NDRG1) has been proposed as a tumor suppressor gene in many different types of tumors, but its potential function and corresponding mechanism are not yet fully elucidated. This study aims to detect the possible function of NDRG1 in gastric cancer progression. In this study, 112 paired gastric cancer tissues and corresponding nonmalignant gastric tissues were utilized to identify the differential protein expression of NDRG1 by immunohistochemistry and its clinical significance was analyzed. Furthermore, 49 of 112 paired gastric specimens were used to detect the differential mRNA expression by real-time PCR. The over expression of NDRG1 in human gastric cancer cell line AGS by PcDNA3.1–NDRG1 transfection was utilized to detect the role of NDRG1 in regulating the biological behavior of gastric cancer. NDRG1 expression was significantly decreased in primary gastric cancer tissues, compared with its corresponding nonmalignant gastric tissues (p < 0.05), and its decreased expression was significantly associated with lymph node metastasis (p < 0.01), invasion depth (p < 0.01) and differentiation (p < 0.05). Additionally, the overall survival rate of gastric cancer patients with high expression of NDRG1 was higher than those with low expression during the follow-up period. NDRG1 overexpression suppressed cells proliferation, invasion and induced a G1 cell cycle arrest in gastric cancer. Furthermore, the down-regulation of NDRG1 in gastric cancer metastatic progression was correlated to E-cadherin and MMP-9. Our results verify that NDRG1 acts as a tumor suppressor gene and may play an important role in the metastasis progression and prognosis of gastric cancer.     

Association of interleukin 1 receptor antagonist (IL1RN) gene polymorphism with recurrent pregnancy loss risk in the North Indian Population and a meta-analysis

An appropriate ratio of interleukin 1 beta to interleukin 1 receptor antagonist (IL1Ra) is required for successful pregnancy. Our objective was to study the genetic association between IL1RN variable numbers of tandem repeat (VNTR) polymorphism and recurrent pregnancy loss (RPL). To analyze the association between IL1RN VNTR allele and RPL, we investigated the IL1RN VNTR polymorphism in 136 RPL patients and in 200 healthy control women. Meta-analysis on this polymorphism was conducted to support our findings. PCR based approach was used to analyze IL1RN VNTR polymorphism and it was further confirmed by sequencing. Systematic review and meta-analysis was done using electronic database (Pub-Med, Google Scholar and Ovid) up to February 27, 2013. This meta-analysis was assessed by comprehensive meta-analysis software version 2. For meta-analysis 549 cases and 1,450 controls were included. The frequency of IL1RN genotype 2/2 was significantly higher in RPL compared to control group (AORs 3.10, 95 % CI 1.58–6.11, p = 0.001). The presence of rare allele also increased the risk of RPL significantly (ORs 1.63, 95 % CI 1.16–2.29, p = 0.004). The meta-analysis stratified by ethnicity showed that individuals with allele 2 had increased risk of RPL (OR 1.29, 95 % CI 1.04–1.61, p = 0.01), in Asians population by using fixed model. However the data of the present study clearly suggests that IL1RN VNTR polymorphism is a genetic risk factor for pregnancy loss in the study population.     

Estradiol inducible and flower-specific expression of ARGOS and ARGOS-LIKE genes in transgenic tobacco plants

Transgenic tobacco plants expressing Arabidopsis thaliana ARGOS and ARGOS-LIKE genes under the control of the chalcone synthase promoter of Petunia hybrida L., as well as the estradiol inducible XVE system, have been obtained. The part of transgenic plants with flower-specific expression of the target genes was characterized by increased flower size, caused by an increase in cell size and quantity in the case of the ARGOS gene and by a stimulation of cell growth via stretching in the case of the ARGOS-LIKE gene. An enhanced expression level of the NtEXPA1, NtEXPA4 genes encoding expansins, NtEXGT gene encoding endo-xyloglucan transferase, and the AINTEGUMENTA-like gene was detected in the flowers of transgenic tobacco plants. In the case of inducible expression of ARGOS and ARGOS-LIKE genes, an increase in leaf, stem and flower size was revealed in several lines of transgenic plants as compared to control. Expression of the ARGOS gene also affected cell number and size in this case, while the ARGOS-LIKE gene mainly influenced cell size via stretching. Inducible expression of the ARGOS gene in flowers mainly provided an enhanced containment of AINTEGUMENTA-like mRNA, while ARGOS-LIKE gene expression resulted in the activation of NtEXPA1 and NtEXGT genes.     

MAPKs as a cross point in H2O2 and auxin signaling under combined cadmium and zinc stress in rice roots

Previously, we have reported the role of MAPKs (mitogen-activated protein kinases) under cadmium stress. This work continue to explore the relationship between MAPKs, H₂O₂, auxin signaling, and OsHMA and OsZIP gene expression in rice (Oryza sativa L.) roots under combined cadmium (Cd) and zinc (Zn) stress. Compared with Cd, Cd+Zn reduced Cd levels but increased Zn accumulation in the roots. Three OsMAPK genes were negatively regulated, while two OsHMA and two OsZIP genes were positively regulated by MAPK pathways under Cd+Zn stress. Transgenic rice expressing DR5-GUS exhibited enhanced GUS activity in H₂O₂-, PD (MAPKK inhibitor PD98059)-, or (Cd+Zn)-treated roots, which also exhibited increased H₂O₂ concentrations, whereas GUS staining decreased in roots in response to Cd+Zn+PD, DMTU (N,N′-dimethylthiourea, a H₂O₂ scavenger), or Cd+Zn+DMTU treatment, with reduced H₂O₂ levels. GUS levels were consistent with H₂O₂ levels, suggesting that MAPK pathway-mediated auxin redistribution occurs via H₂O₂, and H₂O₂ functions downstream of MAPK but upstream of auxin signaling pathways. Furthermore, MAPK pathways serve specific functions in regulating the expression of some key genes of auxin signaling (OsYUCCA, OsPIN, OsARF, and OsIAA) under Cd+Zn stress. Overall, MAPK cascades function in the integration of metal transport, H₂O₂ generation, and auxin signaling in rice seedlings grown under Cd+Zn stress.     

Alpha-Synuclein Oligomerization in Manganese-Induced Nerve Cell Injury in Brain Slices: A Role of NO-Mediated S-Nitrosylation of Protein Disulfide Isomerase

Over-exposure to manganese (Mn) has been known to induce endoplasmic reticulum (ER) stress involving protein misfolding. The proper maturation and folding of native proteins rely on the activity of protein disulfide isomerase (PDI). However, the exact mechanism of Mn-induced alpha-synuclein oligomerization is unclear. To explore whether alpha-synuclein oligomerization was associated with S-nitrosylation of PDI, we made the rat brain slice model of manganism and pretreated slices with l-Canavanine, a selective iNOS inhibitor. After slices were treated with Mn (0, 25, 100, and 400 μM) for 24 h, there were dose-dependent increases in apoptotic percentage of cells, lactate dehydrogenase (LDH) releases, production of NO, inducible nitric oxide synthase (iNOS) activity, the mRNA and protein expressions of iNOS, and PDI. Moreover, S-nitrosylated PDI and alpha-synuclein oligomerization also increased. However, there was a significant increase in the PDI activity of 25-μM Mn-treated slices. Then, PDI activity and the affinity between PDI and alpha-synuclein decreased significantly in response to Mn (100 and 400 μM), which was associated with S-nitrosylation of PDI. The results indicated that S-nitrosylated PDI could affect its activity. We use the l-Canavanine pretreatment brain slices to inhibit S-nitrosylation of PDI. The results showed that l-Canavanine pretreatment could reduce Mn-induced nerve cell injury and alpha-synuclein oligomerization. Additionally, there was a significant recovery in PDI activity in l-Canavanine-pretreated slices. The findings revealed that Mn induced nitrosative stress via the activation of iNOS and subsequent S-nitrosylation of PDI in cultured slices. Moreover, S-nitrosylation of PDI is an important signaling event in the Mn-induced alpha-synuclein oligomerization in brain slices.     

Conformational changes of recombinant human granulocyte-colony stimulating factor induced bypH and guanidine hydrochloride

Fluorescence and circular dichroism were used to follow thepH-dependent conformational changes of granulocyte colony stimulating factor (G-CSF). Tryptophan fluorescence of the spectra monitored at 344 nm, or after deconvolution of the emission spectra, at 345 nm, showed a decrease in intensity on going frompH 7 to 4, with a midtransitionpH of 5.8. On the other hand, tyrosine fluorescence measured either by the ratio of intensity at 308 nm to that at 344 nm, or by the fluorescence intensity at 303 nm after deconvolution of the spectra, increased in intensity as thepH was changed from 6 to 2.5, with a midtransitionpH of 4.5. Near UV circular dichroic spectra also showed changes betweenpH 7.5 and 4.5, which correlated with the transition monitored by the tryptophan fluorescence. The guanidine hydrochloride-induced conformational changes of G-CSF at fivepH values from 2.5 to 7.5 were also studied. Circular dichroic and fluorescence spectra revealed minor conformational changes by the addition of 1 or 2 M guanidine HCl at allpH values examined, while the major conformational transition occurred between 2 and 4 M guanidine hydrochloride. The secondary structure of the protein was most stable betweenpH 3.3 and 4.5. The guanidine HCl-induced denaturation of G-CSF involved more than a two-state transition, with detectable intermediate(s) present, and the structure of the intermediate(s) appeared to depend on thepH used. These results are consistent with thepH dependence of the structure described above, and demonstrate the complex conformational properties of G-CSF.