Background & Aims-Sequential therapy with a proton pump inhibitor (PPI) and amoxicillin followed by a PPI, clarithromycin, and an imidazole agent reportedly have a better rate of curing Helicobacter pylori infection than PPI, amoxicillin, clarithromycin triple therapy. The concomitant administration of these 4 drugs (concomitant therapy) is also an effective treatment strategy. We compared the efficacies of sequential and concomitant therapy and analyzed the effects of antibiotic resistance in patients with H. pylori infection.

Double strand breaks (DSBs) are the most deleterious of the DNA lesions that initiate genomic instability and promote tumorigenesis. Cells have evolved a complex protein network to detect, signal, and repair DSBs. In mammalian cells, a key component in this network is H2AX, which becomes rapidly phosphorylated at Ser 139 (␥-H2AX) at DSBs. Here we show that monoubiquitination of H2AX mediated by the RNF2-BMI1 complex is critical for the efficient formation of ␥-H2AX and functions as a proximal regulator in DDR (DNA damage response). RNF2-BMI1 interacts with H2AX in a DNA damagedependent manner and is required for monoubiquitination of H2AX at Lys 119 /Lys 120 . As a functional consequence, we show that the H2AX K120R mutant abolishes H2AX monoubiquitination, impairs the recruitment of p-ATM (Ser 1981 ) to DSBs, and thereby reduces the formation of ␥-H2AX and the recruitment of MDC1 to DNA damage sites. These data suggest that monoubiquitination of H2AX plays a critical role in initiating DNA damage signaling. Consistent with these observations, impairment of RNF2-BMI1 function by siRNA knockdown or overexpression of the ligase-dead RNF2 mutant all leads to significant defects both in accumulation of ␥-H2AX, p-ATM, and MDC1 at DSBs and in activation of NBS1 and CHK2. Additionally, the regulatory effect of RNF2-BMI1 on ␥-H2AX formation is dependent on ATM. Lacking their ability to properly activate the DNA damage signaling pathway, RNF2-BMI1 complex-depleted cells exhibit impaired DNA repair and increased sensitivity to ionizing radiation. Together, our findings demonstrate a distinct monoubiquitination-dependent mechanism that is required for H2AX phosphorylation and the initiation of DDR. Double strand break (DSB)3 formation in cells immediately triggers the recruitment of DNA damage signaling and repair proteins to the damaged loci, where these proteins form discrete nuclear foci (ionizing radiation (IR)-induced foci). The order and timing of the recruitment of DDR proteins is critical for detection, signaling, and repair of DSBs, which is necessary to maintain genomic stability (1, 2).One of the initial events occurring at DNA damage loci is phosphorylation of H2AX, a histone H2A variant, at Ser 139 of its carboxyl-terminal tail (␥-H2AX) by one or more members of the PI3K-like kinase group, including ATM, ATR, and DNA-PK (3-5). ␥-H2AX decorates the chromatin flanking DSBs and recruits many early DDR proteins, such as MDC1 and BRIT1 (also known as MCPH1), to generate IR-induced foci (6 -10).In addition to phosphorylation of H2AX, ubiquitination of H2AX is an important epigenetic marker for DNA lesions in DDR (11-13). Recent studies have highlighted the function of RING-finger ubiquitin ligases RNF8 and RNF168 in promoting accumulation of repair proteins at DSBs in an MDC1-dependent manner (14 -19). As expected, accumulating in vitro and in vivo studies have demonstrated that modifications of H2AX play a central role in regulating various cellular responses to DSBs, including DNA repair, cell cycle checkpoints, ...

Advanced glycation end-product (AGE) is important in the pathogenesis of diabetic nephropathy (DN), and captopril (an angiotensin converting enzyme inhibitor) is effective in treating this disorder. We have shown that the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) cascade is responsible for AGE-induced mitogenesis in NRK-49F (normal rat kidney fibroblast) cells, but its role in renal fibrosis in DN remains unknown. Therefore, we have sought to determine whether JAK/STAT is involved in AGE-regulated collagen production in NRK-49F cells. We found that AGE time (1-7 days) and dose (10-200 microg/ml)-dependently increased collagen production in these cells. Additionally, AGE increased RAGE (receptor for AGE) protein expression. AGE-induced RAGE expression was dose-dependently inhibited by antisense RAGE oligodeoxynucleotide (ODN) and captopril. AGE-induced type I collagen production and JAK2-STAT1/STAT3 activation were decreased by AG-490 (a specific JAK2 inhibitor), antisense RAGE ODN and captopril. Meanwhile, STAT1 and STAT3 decoy ODNs also suppressed the induction of collagen by AGE. We concluded that RAGE and the JAK2-STAT1/STAT3 pathway were involved in AGE-induced collagen production in NRK-49F cells. Furthermore, captopril was found to reverse AGE-induced collagen production, probably by attenuating RAGE expression and JAK2-STAT1/STAT3 activities.

Originally identified as a metabolic enzyme that catalyzes the transfer of a phosphate group from phosphoenolpyruvate (PEP) to ADP in the glycolytic pathway, pyruvate kinase M2-type (PKM2) has been shown to exhibit novel biological activities in the nucleus and outside the cells. Although cell-based studies reveal new non-canonical functions of PKM2 in gene transcription, epigenetic modulation and cell cycle progression, the importance of these non-canonical functions in PKM2-mediated tumorigenesis is still under debate because studies in genetically modified mice do not consistently echo the findings observed in cultured cancer cells. In addition to regulation of gene expression, the existence of PKM2 in exosomes opens a new venue to study the potential role of this glycolytic enzyme in cell-cell communication and extracellular signal initiation. In this review, we briefly summarize current understanding of PKM2 in metabolic switch and gene regulation. We will then emphasize recent progress of PKM2 in extracellular signaling and tumor microenvironment reprogramming. Finally, the discrepancy of some PKM2’s functions in vitro and in vivo, and the application of PKM2 in cancer detection and treatment will be discussed.

Recent studies demonstrate that cyclooxygenase-2 (COX-2) expression is frequently associated with lymph node metastasis. However, the mechanism by which COX-2 increases the invasion of cancer cells to lymph node is unclear. CCR7 is a chemokine receptor that plays important roles in the mediation of

Purpose: Prospero homeobox 1 (PROX1) has been shown to function as a tumor suppressor in various types of cancer. However, it promotes colon cancer progression. The aim of this study is to clarify the underlying mechanism by which PROX1 regulates tumorigenicity of colon cancer.Experimental Design: Association of PROX1 and clinicopathological features was studied by immunohistochemical staining. Pri-miR-9-2 and miR-9 were detected by quantitative real-time PCR. Assays of cell invasion, adhesion, and matrix metalloproteinase activity were used to study PROX1-mediated epithelialmesenchymal transition (EMT).Results: PROX1 was overexpressed in 43% (59/136) of colon cancer tissues and its expression was correlated with E-cadherin downregulation (P ¼ 0.00005), advanced tumor staging (P ¼ 0.005), and lymph node metastasis (P ¼ 0.000009). Enforced expression of PROX1 in DLD-1 cells caused downregulation of Ecadherin and integrins and attenuated cell adhesion. These cells showed increase of matrix metalloproteinase activity and invasive ability. Conversely, knockdown of PROX1 in SW620 cells restored E-cadherin protein expression and reduced invasiveness. Unexpectedly, repression of E-cadherin by PROX1 was not mediated by transcriptional inhibition. We found that PROX1 bound to miR-9-2 promoter and triggered its expression to suppress E-cadherin 3 0 UTR reporter activity and protein expression. Anti-miR-9 restored Ecadherin in SW620 cells, whereas precursor miR-9 inhibited E-cadherin in PROX1-knockdown cells. The miR-9 level was higher in tumor tissues with high PROX1/low E-cadherin than that of tumor tissues with low PROX1/high E-cadherin. Conclusions: Our results provide mechanistic insights by which PROX1 promotes EMT and colon cancer progression. Targeting of PROX1-mediated oncogenic activity may be helpful for the treatment of colon cancer. Clin Cancer Res; 18(23); 6416-25. Ó2012 AACR.

Matrix metalloproteinase (MMP) inhibitory proteins may negatively regulate MMP activity to suppress tumor metastasis. In this study, we demonstrate that the HER-2/neu oncogene inhibits the expression of the MMP inhibitor RECK to promote cell invasion. RECK was inhibited via transcriptional repression in B104-1-1 cells, which express constitutively active HER-2/neu. Overexpression of HER-2/neu in NIH/3T3 or HaCaT cells also suppressed RECK expression. Deletion and mutation assays showed that HER-2/neu repressed RECK via the Sp1-binding site localized in the ؊82/؊71 region from the translational start site. DNA affinity precipitation and chromatin immunoprecipitation assays indicated that binding of Sp1 and Sp3 to this consensus site was increased in B104-1-1 cells. We also found that HER-2/neu inhibited RECK via the ERK signaling pathway. Sp1 proteins phosphorylated at Thr 453 and Thr 739 by ERK bound preferentially to the RECK promoter, and this binding was reversed by HER-2/neu and ERK inhibitors. Furthermore, our data indicate that HER-2/neu obviously increased HDAC1 binding to the Sp1-binding site localized in the ؊82/؊71 region of the RECK promoter. The histone deacetylase inhibitor trichostatin A reversed HER-2/neu-induced inhibition of RECK. HER-2/neu activation was associated with increased MMP-9 secretion and activation. Re-expression of RECK in HER-2/neu-overexpressing cells inhibited MMP-9 secretion and cell invasion. Taken together, our results suggest that HER-2/neu induces the binding of Sp proteins and HDAC1 to the RECK promoter to inhibit RECK expression and to promote cell invasion. Restoration of RECK provides a novel strategy for the inhibition of HER-2/neu-induced metastasis.The HER-2/neu oncogene (also known as erbB2) encodes a transmembrane glycoprotein that belongs to the human epidermal growth factor receptor family (1, 2). Structural analysis of HER-2/neu and the epidermal growth factor receptor revealed significant sequence homology and identical gross structural organization between these two proteins (3-5). Amplification and overexpression of HER-2/neu have been found in breast, ovarian, lung, gastric, and cervical carcinomas (6 -10). Up-regulation of this oncogene is frequently linked with increased metastasis and poor prognosis. The mechanism underlying HER-2/neuinduced metastasis is a field of intensive study, and several candidates involved in this process have been identified recently. The first candidate is the vascular endothelial growth factor. HER-2/neu may stimulate vascular endothelial growth factor expression, and neutralizing antibody against HER-2/neu suppresses vascular endothelial growth factor production and metastasis of cancer cells (11,12). The second is the urokinase-type plasminogen activator. Induction of the urokinase-type plasminogen activator by HER-2/neu has been shown to be correlated with increased metastasis (13). The third is cyclooxygenase-2. Cyclooxygenase-2 plays a critical role in tumor metastasis and may be a potential target for chemoprevention (14)...

SKP2 is the ubiquitin ligase subunit that targets p27 KIP1(p27) for degradation. SKP2 is induced in the G 1 -S transit of the cell cycle, is frequently overexpressed in human cancer, and displays transformation activity in experimental models. Here we show that MYC induces SKP2 expression at the mRNA and protein levels in human myeloid leukemia K562 cells with conditional MYC expression. Importantly, in these systems, induction of MYC did not activate cell proliferation, ruling out SKP2 up-regulation as a consequence of cell cycle entry. MYC-dependent SKP2 expression was also detected in other cell types such as lymphoid, fibroblastic, and epithelial cell lines. MYC induced SKP2 mRNA expression in the absence of protein synthesis and activated the SKP2 promoter in luciferase reporter assays. With chromatin immunoprecipitation assays, MYC was detected bound to a region of human SKP2 gene promoter that includes E-boxes. The K562 cell line derives from human chronic myeloid leukemia. In a cohort of chronic myeloid leukemia bone marrow samples, we found a correlation between MYC and SKP2 mRNA levels. Analysis of cancer expression databases also indicated a correlation between MYC and SKP2 expression in lymphoma. Finally, MYC-induced SKP2 expression resulted in a decrease in p27 protein in K562 cells. Moreover, silencing of SKP2 abrogated the MYC-mediated down-regulation of p27. Our data show that SKP2 is a direct MYC target gene and that MYC-mediated SKP2 induction leads to reduced p27 levels. The results suggest the induction of SKP2 oncogene as a new mechanism for MYC-dependent transformation.c-MYC (hereafter MYC) is an oncogenic transcription factor of the helix-loop-helix/leucine zipper protein family. MYC exerts a wide array of biological functions in different cellular models related to cell cycle control, genomic instability, energetic metabolism, protein synthesis, intercellular communication, and control of cell differentiation (for reviews see Refs.