Increased expression of h-prune is associated with tumor progression and poor survival in gastric cancer

The human homolog of the Drosophila prune protein (from PRUNE, which encodes h-prune), which interacts with glycogen synthase kinase 3, promotes cellular motility. H-prune also interacts with nm23-H1, a suppressor of cancer metastasis. It has been reported that stimulation of cellular motility by h-prune is enhanced by its interaction with nm23-H1 in breast cancer cells. In the present study, we examined the expression of h-prune and nm23-H1 during tumor progression in gastric cancer (GC). PRUNE mRNA was overexpressed in 12 (32%) of 38 GC cases by quantitative reverse transcription-polymerase chain reaction. PRUNE mRNA levels correlated significantly with advanced T grade, N grade and tumor stage. Immunohistochemical analysis revealed that 43 (30%) of 143 GC cases were positive for h-prune, and h-prune-positive GC cases showed more advanced T grade, N grade and tumor stage than h-prune-negative GC cases. One hundred and twenty-four (87%) of 143 GC cases were positive for nm23-H1, and nm23-H1 was expressed in almost all (42 cases, 98%) h-prune-positive GC cases. Many GC cases positive for both h-prune and nm23-H1 showed more advanced T grade, N grade and tumor stage than other type GC cases. Patients with h-prune-positive GC had a significantly worse survival rate than patients with h-prune-negative GC. These findings indicate that overexpression of h-prune is associated with tumor progression and aggressiveness of GC. nm23-H1 may enhance motility of cancer cells by interacting with h-prune. (Cancer Sci 2007; 98: 1198-1205

MAPK ERK Signaling Regulates the TGF-β1-Dependent Mosquito Response to Plasmodium falciparum

Malaria is caused by infection with intraerythrocytic protozoa of the genus Plasmodium that are transmitted by Anopheles mosquitoes. Although a variety of anti-parasite effector genes have been identified in anopheline mosquitoes, little is known about the signaling pathways that regulate these responses during parasite development. Here we demonstrate that the MEK-ERK signaling pathway in Anopheles is controlled by ingested human TGF-β1 and finely tunes mosquito innate immunity to parasite infection. Specifically, MEK-ERK signaling was dose-dependently induced in response to TGF-β1 in immortalized cells in vitro and in the A. stephensi midgut epithelium in vivo. At the highest treatment dose of TGF-β1, inhibition of ERK phosphorylation increased TGF-β1-induced expression of the anti-parasite effector gene nitric oxide synthase (NOS), suggesting that increasing levels of ERK activation negatively feed back on induced NOS expression. At infection levels similar to those found in nature, inhibition of ERK activation reduced P. falciparum oocyst loads and infection prevalence in A. stephensi and enhanced TGF-β1-mediated control of P. falciparum development. Taken together, our data demonstrate that malaria parasite development in the mosquito is regulated by a conserved MAPK signaling pathway that mediates the effects of an ingested cytokine

Rosiglitazone Inhibits Transforming Growth Factor-β1 Mediated Fibrogenesis in ADPKD Cyst-Lining Epithelial Cells

BACKGROUND: Interstitial fibrosis plays an important role in progressive renal dysfunction in autosomal dominant polycystic kidney disease (ADPKD). In our previous studies, we confirmed that PPAR-γ agonist, rosiglitazone could protect renal function and prolong the survival of a slowly progressive ADPKD animal model by reducing renal fibrosis. However, the mechanism remains unknown. METHODS: Primary culture epithelial cells pretreated with TGF-β1 were incubated with rosiglitazone. Extracellular matrix proteins were detected using real-time PCR and Western blotting. MAPK and Smad2 phosphorylation were measured with western blot. ERK1/2 pathway and P38 pathway were inhibited with the specific inhibitors PD98059 and SB203580. The Smad2 pathway was blocked with the siRNA. To address whether PPAR-γ agonist-mediated inhibition of TGF-β1-induced collagen type I expression was mediated through a PPAR-γ dependent mechanism, genetic and pharmaceutical approaches were used to block the activity of endogenous PPARγ. RESULTS: TGF-β1-stimulated collagen type I and fibronectin expression of ADPKD cyst-lining epithelia were inhibited by rosiglitazone in a dosage-dependent manner. Smad2, ERK1/2 and P38 pathways were activated in response to TGF-β1; however, TGF-β1 had little effect on JNK pathway. Rosiglitazone suppressed TGF-β1 induced Smad2 activation, while ERK1/2 and P38MAPK signals remained unaffected. Rosiglitazone could also attenuate TGF-β1-stimulated collagen type I and fibronectin expression in primary renal tubular epithelial cells, but had no effect on TGF-β1-induced activation of Smad2, ERK1/2 and P38 pathways. There was no crosstalk between the Smad2 and MAPK pathways in ADPKD cyst-lining epithelial cells. These inhibitory effects of rosiglitazone were reversed by the PPARγ specific antagonist GW9662 and PPARγ siRNA. CONCLUSION: ADPKD cyst-lining epithelial cells participate in TGF-β1 mediated fibrogenesis. Rosiglitazone could suppress TGF-β1-induced collagen type I and fibronectin expression in ADPKD cyst-lining epithelia through modulation of the Smad2 pathway. Our study may provide therapeutic basis for clinical applications of rosiglitazone in retarding the progression of ADPKD

Sponge non-metastatic Group I Nme gene/protein - structure and function is conserved from sponges to humans

<p>Abstract</p> <p>Background</p> <p>Nucleoside diphosphate kinases NDPK are evolutionarily conserved enzymes present in Bacteria, Archaea and Eukarya, with human Nme1 the most studied representative of the family and the first identified metastasis suppressor. Sponges (Porifera) are simple metazoans without tissues, closest to the common ancestor of all animals. They changed little during evolution and probably provide the best insight into the metazoan ancestor's genomic features. Recent studies show that sponges have a wide repertoire of genes many of which are involved in diseases in more complex metazoans. The original function of those genes and the way it has evolved in the animal lineage is largely unknown. Here we report new results on the metastasis suppressor gene/protein homolog from the marine sponge <it>Suberites domuncula</it>, NmeGp1Sd. The purpose of this study was to investigate the properties of the sponge Group I Nme gene and protein, and compare it to its human homolog in order to elucidate the evolution of the structure and function of Nme.</p> <p>Results</p> <p>We found that sponge genes coding for Group I Nme protein are intron-rich. Furthermore, we discovered that the sponge NmeGp1Sd protein has a similar level of kinase activity as its human homolog Nme1, does not cleave negatively supercoiled DNA and shows nonspecific DNA-binding activity. The sponge NmeGp1Sd forms a hexamer, like human Nme1, and all other eukaryotic Nme proteins. NmeGp1Sd interacts with human Nme1 in human cells and exhibits the same subcellular localization. Stable clones expressing sponge NmeGp1Sd inhibited the migratory potential of CAL 27 cells, as already reported for human Nme1, which suggests that Nme's function in migratory processes was engaged long before the composition of true tissues.</p> <p>Conclusions</p> <p>This study suggests that the ancestor of all animals possessed a NmeGp1 protein with properties and functions similar to evolutionarily recent versions of the protein, even before the appearance of true tissues and the origin of tumors and metastasis.</p

TGF-β-Mediated Sustained ERK1/2 Activity Promotes the Inhibition of Intracellular Growth of Mycobacterium avium in Epithelioid Cells Surrogates

Transforming growth factor beta (TGF-β) has been implicated in the pathogenesis of several diseases including infection with intracellular pathogens such as the Mycobacterium avium complex. Infection of macrophages with M. avium induces TGF-β production and neutralization of this cytokine has been associated with decreased intracellular bacterial growth. We have previously demonstrated that epithelioid cell surrogates (ECs) derived from primary murine peritoneal macrophages through a process of differentiation induced by IL-4 overlap several features of epithelioid cells found in granulomas. In contrast to undifferentiated macrophages, ECs produce larger amounts of TGF-β and inhibit the intracellular growth of M. avium. Here we asked whether the levels of TGF-β produced by ECs are sufficient to induce a self-sustaining autocrine TGF-β signaling controlling mycobacterial replication in infected-cells. We showed that while exogenous addition of increased concentration of TGF-β to infected-macrophages counteracted M. avium replication, pharmacological blockage of TGF-β receptor kinase activity with SB-431542 augmented bacterial load in infected-ECs. Moreover, the levels of TGF-β produced by ECs correlated with high and sustained levels of ERK1/2 activity. Inhibition of ERK1/2 activity with U0126 increased M. avium replication in infected-cells, suggesting that modulation of intracellular bacterial growth is dependent on the activation of ERK1/2. Interestingly, blockage of TGF-β receptor kinase activity with SB-431542 in infected-ECs inhibited ERK1/2 activity, enhanced intracellular M. avium burden and these effects were followed by a severe decrease in TGF-β production. In summary, our findings indicate that the amplitude of TGF-β signaling coordinates the strength and duration of ERK1/2 activity that is determinant for the control of intracellular mycobacterial growth

Aurora-A overexpression enhances cell-aggregation of Ha-ras transformants through the MEK/ERK signaling pathway

<p>Abstract</p> <p>Background</p> <p>Overexpression of Aurora-A and mutant Ras (Ras^V12) together has been detected in human bladder cancer tissue. However, it is not clear whether this phenomenon is a general event or not. Although crosstalk between Aurora-A and Ras signaling pathways has been reported, the role of these two genes acting together in tumorigenesis remains unclear.</p> <p>Methods</p> <p>Real-time PCR and sequence analysis were utilized to identify Ha- and Ki-<it>ras </it>mutation (Gly -> Val). Immunohistochemistry staining was used to measure the level of Aurora-A expression in bladder and colon cancer specimens. To reveal the effect of overexpression of the above two genes on cellular responses, mouse NIH3T3 fibroblast derived cell lines over-expressing either Ras^V12and wild-type Aurora-A (designated WT) or Ras^V12and kinase-inactivated Aurora-A (KD) were established. MTT and focus formation assays were conducted to measure proliferation rate and focus formation capability of the cells. Small interfering RNA, pharmacological inhibitors and dominant negative genes were used to dissect the signaling pathways involved.</p> <p>Results</p> <p>Overexpression of wild-type Aurora-A and mutation of Ras^V12were detected in human bladder and colon cancer tissues. Wild-type Aurora-A induces focus formation and aggregation of the Ras^V12transformants. Aurora-A activates Ral A and the phosphorylation of AKT as well as enhances the phosphorylation of MEK, ERK of WT cells. Finally, the Ras/MEK/ERK signaling pathway is responsible for Aurora-A induced aggregation of the Ras^V12transformants.</p> <p>Conclusion</p> <p>Wild-type-Aurora-A enhances focus formation and aggregation of the Ras^V12transformants and the latter occurs through modulating the Ras/MEK/ERK signaling pathway.</p

Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues

<p>Abstract</p> <p>Background</p> <p>During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS) are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH), ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC).</p> <p>Methods</p> <p>Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue.</p> <p>Results</p> <p>We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue.</p> <p>Conclusions</p> <p>Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells.</p

Molecular biology of breast cancer metastasis: Genetic regulation of human breast carcinoma metastasis

The present is an overview of recent data that describes the genetic underpinnings of the suppression of cancer metastasis. Despite the explosion of new information about the genetics of cancer, only six human genes have thus far been shown to suppress metastasis functionally. Not all have been shown to be functional in breast carcinoma. Several additional genes inhibit various steps of the metastatic cascade, but do not necessarily block metastasis when tested using in vivo assays. The implications of this are discussed. Two recently discovered metastasis suppressor genes block proliferation of tumor cells at a secondary site, offering a new target for therapeutic intervention