Metastasis of human gastric adenocarcinoma partly depends on phosphoinositide-specific phospholipase γ1 expression

It is known that phosphoinositide-specific phospholipases γ1(PLCγ1) can trigger several signalling pathways to regulate cell proliferation, differentiation, and metastasis. However, whether this kinase is highly expressive and active in human gastric adenocarcinomas, and whether it can play an important role in the development of the cancer, have not yet been investigated. The aim of the study was to investigate the expression of PLCγ1 in human gastric adenocarcinoma, while the question of whether PLCγ1 can be activated through protein kinase B (Akt) signalling pathways to regulate cell migration was further explored using human gastric adenocarcinoma BGC-823 cell line. The expression of PLCγ1 in human adenocarcinoma was detected using immunohistochemical staining. The BGC-823 cells were cultured and treated with inhibitors or transfected with plasmid construction. The cell migration of BGC-823 cells was measured with wound healing assay, cell migration assay, and the ruffling assay. The expression levels of PLCγ1 and its related signal molecules in BGC-823 cells were assessed using Western blot analysis or gelatine zymography assay. PLCγ1 was highly expressed in humangastric adenocarcinomas, especially in the region with lymph node metastasis. It was shown that migration of BGC-823 cells in vitro depends on PLCγ1 activation. This activation is mediated through Akt, an upstream of PLCγ1 that triggers the PLCγ1/extracellular signal-regulated kinase (ERK)/matrix metalloproteinase (MMP) pathway in BGC-823 cells. PLCγ1 activities play an important role in the metastasis of gastric adenocarcinoma, and may serve as a potential therapeutic target in this type of cancer

Comparing the route-choice behavior of pedestrians around obstacles in a virtual experiment and a field study

Pedestrians often need to decide between different routes they can use to reach their intended destinations, both during emergencies and in their daily lives. This route-choice behavior is important in determining traffic management, evacuation efficiency and building design. Here, we use field observations and a virtual experiment to study the route choice behavior of pedestrians around obstacles delimiting exit routes and examine the influence of three factors, namely the local distance to route starting points and the pedestrian density and walking speeds along routes. Crucially, both field study and virtual experiment consider the same scenario which allows us to directly assess the validity of testing pedestrian behavior in virtual environments. We find that in both data sets the proportion of people who choose a closer exit route increases as the difference in distance between exit route starting points increases. Pedestrians' choices in our data also depend on pedestrian density along routes, with people preferring less used routes. Our results thus confirm previously established route choice mechanisms and we can predict over 74% of choices based on these factors. The qualitative agreement in results between the field study and the virtual experiment suggests that in simple route-choice scenarios, such as the one we investigate here, virtual experiments can be a valid experimental technique for studying pedestrian behavior. We therefore provide much-needed empirical support for the emerging paradigm of experiments in virtual environments

An enhanced U6 promoter for synthesis of short hairpin RNA

Short hairpin RNAs (shRNAs) transcribed by RNA polymerase III (Pol III) promoters can trigger sequence-selective gene silencing in culture and in vivo and, therefore, may be developed to treat diseases caused by dominant, gain-of-function type of gene mutations. These diseases develop in people bearing one mutant and one wild-type gene allele. While the mutant is toxic, the wild-type performs important functions. Thus, the ideal therapy must selectively silence the mutant but maintain the wild-type expression. To achieve this goal, we designed an shRNA that selectively silenced a mutant Cu,Zn superoxide dismutase (SOD1(G93A)) allele that causes amyotrophic lateral sclerosis. However, the efficacy of this shRNA was relatively modest. Since the allele-specific shRNA has to target the mutation site, we could not scan other regions of SOD1 mRNA to find the best silencer. To overcome this problem, we sought to increase the dose of this shRNA by enhancing the Pol III promoter. Here we demonstrate that the enhancer from the cytomegalovirus immediate-early promoter can enhance the U6 promoter activity, the synthesis of shRNA and the efficacy of RNA interference (RNAi). Thus, this enhanced U6 promoter is useful where limited choices of shRNA sequences preclude the selection of a highly efficient RNAi target region

RAS‐targeted cancer therapy: Advances in drugging specific mutations

Abstract Rat sarcoma (RAS), as a frequently mutated oncogene, has been studied as an attractive target for treating RAS‐driven cancers for over four decades. However, it is until the recent success of kirsten‐RAS (KRAS)G12C inhibitor that RAS gets rid of the title “undruggable”. It is worth noting that the therapeutic effect of KRASG12C inhibitors on different RAS allelic mutations or even different cancers with KRASG12C varies significantly. Thus, deep understanding of the characteristics of each allelic RAS mutation will be a prerequisite for developing new RAS inhibitors. In this review, the structural and biochemical features of different RAS mutations are summarized and compared. Besides, the pathological characteristics and treatment responses of different cancers carrying RAS mutations are listed based on clinical reports. In addition, the development of RAS inhibitors, either direct or indirect, that target the downstream components in RAS pathway is summarized as well. Hopefully, this review will broaden our knowledge on RAS‐targeting strategies and trigger more intensive studies on exploiting new RAS allele‐specific inhibitors

Comparing the route-choice behavior of pedestrians around obstacles in a virtual experiment and a field study

There is a great controversy about the application of virtual experiment in pedestrian routing behavior research. We conducted field observations and virtual experiment to study the route choice behavior of pedestrians. The route choice behavior around obstacles are compared qualitatively. The results shows that distance to the exit routes as well as the density around the exits show great influence on the pedestrians' route choice behavior while the speed of frontal pedestrians shows no obvious impact on the route choice. Pedestrians prefer to choose local closer exit or the exit with less occupants. The results of logistic regression show that the similar results can be obtained in virtual experiment and field observation qualitatively. This work can verify the validity of the virtual experiment for studying route choice behavior of pedestrians, which is of great importance for the application of virtual experiment. The files are trajectories of the recorded videos in the field observation

Selective silencing by RNAi of a dominant allele that causes amyotrophic lateral sclerosis

RNA interference (RNAi) can achieve sequence-selective inactivation of gene expression in a wide variety of eukaryotes by introducing double-stranded RNA corresponding to the target gene. Here we explore the potential of RNAi as a therapy for amyotrophic lateral sclerosis (ALS) caused by mutations in the Cu, Zn superoxide dismutase (SOD1) gene. Although the mutant SOD1 is toxic, the wild-type SOD1 performs important functions. Therefore, the ideal therapeutic strategy should be to selectively inhibit the mutant, but not the wild-type SOD1 expression. Because most SOD1 mutations are single nucleotide changes, to selectively silence the mutant requires single-nucleotide specificity. By coupling rational design of small interfering RNAs (siRNAs) with their validation in RNAi reactions in vitro and in vivo, we have identified siRNA sequences with this specificity. A similarly designed sequence, when expressed as small hairpin RNA (shRNA) under the control of an RNA polymerase III (pol III) promoter, retains the single-nucleotide specificity. Thus, RNAi is a promising therapy for ALS and other disorders caused by dominant, gain-of-function gene mutations