Helicobacter pylori, a gram-negative spiral bacterium, is the cause of chronic superficial (type B) gastritis and peptic ulcer disease. The urease enzyme of H. pylori was expressed as an inactive recombinant protein in Escherichia coli, purified as particulate structures of 550-600 kDa molecular mass with a diameter of approximately 12 nm. Given orally, 5 micrograms of urease with an appropriate mucosal adjuvant, such as the labile toxin of E. coli, protected 60%-100% of mice against challenge with virulent Helicobacter felis. Protection correlated with the level of secretory IgA antibodies against urease. Oral administration of antigen was as effective or better than intragastric administration. Parenteral injection of antigen or intragastric administration of high-dose antigen without adjuvant elicited serum IgG but no IgA antibodies and did not confer protection. Recombinant urease as an oral vaccine candidate deserves further investigation as an approach to the prevention of Helicobacter-induced chronic gastroduodenal diseases in humans.

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The coexpression of erbB3 and erbB2 is frequently observed in breast cancer; and erbB3 has a critical role in erbB2 promotion of breast cancer progression and anti-estrogen resistance. In this study, we determine the role of erbB3 in erbB2-mediated paclitaxel resistance in breast cancer cells. The overexpression of exogenous erbB3 via either stable or transient transfection in erbB2-overexpressing, but not epidermal growth factor receptor (EGFR)-expressing, breast cancer cells significantly decreases paclitaxel-induced growth inhibition and apoptosis. Consistently, knockdown of erbB3 expression with a specific short hairpin RNA (shRNA) in breast cancer cells with coexpression of both erbB2 and erbB3 enhances paclitaxel-induced apoptosis evidenced by increased DNA fragmentation, poly (ADP-ribose) polymerase (PARP) cleavage and activation of caspase-3 and -8. Furthermore, while forced overexpression of erbB3 increases, specific knockdown of erbB3 decreases the expression levels of Survivin only in the erbB2-overexpressing breast cancer cells. Targeting Survivin with specific shRNA overcomes paclitaxel resistance without effect on the expression levels of either erbB2 or erbB3. Mechanistic studies indicate that the specific phosphoinositide 3-kinase (PI-3K), Akt and mammalian target of rapamycin (mTOR) inhibitors, but not the mitogen-activated protein kinase kinase (MEK) inhibitor, not only abrogate erbB3-mediated upregulation of Survivin, but also reinforce the erbB2/erbB3-coexpressing breast cancer cells to paclitaxel-induced growth inhibition. These data demonstrate that heterodimerization of erbB2/erbB3 is a prerequisite for erbB2 tyrosine kinase activation; and elevated expression of erbB3 is required for erbB2-mediated paclitaxel resistance in breast cancer cells via PI-3K/Akt/ mTOR signaling pathway-dependent upregulation of Survivin. Our studies suggest that new strategies targeting erbB3 or Survivin may enhance the efficacy of chemotherapeutic agents against erbB2-overexpressing breast cancer.

We reported that the class I HDAC inhibitor entinostat induced apoptosis in erbB2-overexpressing breast cancer cells via downregulation of erbB2 and erbB3. Here, we study the molecular mechanism by which entinostat dual-targets erbB2/erbB3. Treatment with entinostat had no effect on erbB2/erbB3 mRNA, suggesting a transcription-independent mechanism. Entinostat decreased endogenous but not exogenous erbB2/erbB3, indicating it did not alter their protein stability. We hypothesized that entinostat might inhibit erbB2/erbB3 protein translation via specific miRNAs. Indeed, entinostat significantly upregulated miR-125a, miR-125b, and miR-205, that have been reported to target erbB2 and/or erbB3. Specific inhibitors were then used to determine whether these miRNAs had a causal role in entinostat-induced downregulation of erbB2/erbB3 and apoptosis. Transfection with a single inhibitor dramatically abrogated entinostat induction of miR-125a, miR-125b, or miR-205; however, none of the inhibitors blocked entinostat action on erbB2/erbB3. In contrast, co-transfection with two inhibitors not only reduced their corresponding miRNAs, but also significantly abrogated entinostat-mediated reduction of erbB2/erbB3. Moreover, simultaneous inhibition of two, but not one miRNA significantly attenuated entinostat-induced apoptosis. Interestingly, although the other HDAC inhibitors, such as SAHA and panobinostat, exhibited activity as potent as entinostat to induce growth inhibition and apoptosis in erbB2-overexpressing breast cancer cells, they had no significant effects on the three miRNAs. Instead, both SAHA- and panobinostat-decreased erbB2/erbB3 expression correlated with the reduction of their mRNA levels. Collectively, we demonstrate that entinostat specifically induces expression of miR-125a, miR-125b, and miR-205, which act in concert to downregulate erbB2/erbB3 in breast cancer cells. Our data suggest that epigenetic regulation via miRNA-dependent or -independent mechanisms may represent a novel approach to treat breast cancer patients with erbB2-overexpressing tumors.

SUMMARYBackground: Colorectal cancer is one of the most common forms of gastrointestinal cancer in the world today. In the Asia-Pacific area, it is the fastest emerging gastrointestinal cancer. Aim: To determine the basic demographic features of patients with colorectal cancer and the anatomic distribution and characteristics of the tumour in a local Asian population. Methods: We conducted a review of consecutive patients who had undergone colonoscopy from

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In recent years, digital games have assumed an important place in the lives of children and adolescents. Effective content design is crucial to the success of digital game-based learning. Therefore, the tool for assessing the effectiveness of game design is accordingly very important for parents and teachers, so that they may encourage or discourage students to play. The purpose of this study is to develop an assessment tool to examine the educational values of digital games. In the first phase of this research, the research team developed the indices for assessing the educational values of digital games. An expert panel consisting of game scholars and professional game designers was established to construct the indices for evaluating digital games in three focus group discussions. Seventy-four game evaluation indices were sorted into seven categories: mentality change, emotional fulfilment, knowledge enhancement, thinking skill development, interpersonal skill development, spatial ability development and bodily coordination. In the second phase of the research, the game designers were asked to assess certain games by using the 74 indices. Meanwhile, the game scholars were also asked to evaluate the same pool of games by the same indices. The assessments by both the scholars and designers were then compared and the similarities were found. This research provided a preliminary framework for future game designers, parents and teachers in assessing educational values of digital games.

Phenytoin (PHT) is a common cause of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). Although HLA-B*15:02 is associated with PHT-induced SJS/TEN (PHT-SJS/TEN) in Han Chinese and Thais, the genetic basis for susceptibility to PHT-induced SCARs (PHT-SCAR) in other populations remains unclear. We performed a case-control association study by genotyping the human leukocyte antigen (HLA)-B alleles of 16 Malay PHT-SCAR patients (13 SJS/TEN and 3 DRESS), 32 PHT-tolerant controls and 300 healthy ethnicity-matched controls. A novel genetic biomarker, HLA-B*15:13, showed significant association with PHT-SJS/TEN (53.8%, 7/13 cases) (odds ratio (OR) 11.28, P=0.003) and PHT-DRESS (100%, 3/3 cases) (OR 59.00, P=0.003) when compared with PHT-tolerant controls (9.4%, 3/32 controls). We also confirmed HLA-B*15:02 association with PHT-SJS/TEN (61.5%, 8/13 cases vs 21.9%, 7/32 controls; OR 5.71, P=0.016) when compared with PHT-tolerant controls. These alleles may serve as markers to predict PHT-SCAR in Malays.