Roles of AKT1 and AKT2 in non-small cell lung cancer cell survival, growth, and migration.

Although AKT / protein kinase B is constitutively active in nonsmall cell lung cancer (NSCLC) cells and is an attractive target for enhancing the cytotoxicity of therapeutic agents, the distinct roles of the AKT isoforms in NSCLC are largely unknown. In the present study, we investigated the roles of AKT1 and AKT2 in NSCLC cells using RNAi. The siRNA targeting of AKT1 or AKT2 effectively decreased protein levels of AKT1 and AKT2, respectively, in A549 and H460 cells. Cisplatin treatment of these cells increased apoptotic cell death compared with control. The siRNA-induced knockdown of AKT1 in H460 cells significantly decreased basal MEK/ ERK1 / 2 activity, resulting in nuclear factor-κB activation, whereas knockdown of AKT2 resulted in anti-apoptotic Bcl-2 family protein MCL-1 (MCL-1) cleavage, the collapse of mitochondrial membrane potential, cytochrome c release, and activation of the caspase cascade. Consequently, both siRNA treatments enhanced the chemosensitivity of H460 cells to cisplatin. However, neither AKT1 nor AKT2 siRNA treatment had any effect of p27 expression, and although both treatments tended to induced G2 /M phase arrest, the effect was not statistically significant. Treatment with AKT1 siRNA markedly decreased colony formation growth and migration, but AKT2 siRNA had no significant effects on these parameters. These data suggest that AKT1 and AKT2 both contribute to cell survival, albeit via different mechanisms, and that the effects on cell growth and migration are predominantly regulated by AKT1. These findings may aid in refining targeted strategies for the inhibition of AKT isoforms towards the sensitization of NSCLC cells to therapeutic agents.

Development and validation of virtual driving simulator for the spinal injury patient.

We developed a virtual reality (VR) driving simulator in order to safely evaluate and improve the driving ability of spinal injury patients. The simulator is composed of an actual car, a beam projector, and a large screen. For the interface of our driving simulator, an actual car was adapted and then connected to a computer. We equipped the car with hand control driving devices especially adapted for spinal injury patients. A beam projector was used so that the subjects could see the virtual scene on a large screen set up in front of them. The virtual environment (VE) consisted of 18 sections (e.g., a speed-limited road, a straight road, a curved road, a left turn) and each section was linked naturally to the next. The subjects selected for this trial were 10 normal drivers with valid driving licenses and 15 patients with thoracic or lumbar cord injuries who had prior driving experience. For evaluation, five driving skills were measured, including average speed, steering stability, centerline violations, traffic signal violations, and driving time in various road conditions such as straight and curved roads. The normal subjects manipulated the gas pedal and the brake with their feet, while the patients manipulated a hand control with their hands. After they finished driving the whole course, the participants answered the questions such as "How realistic did the virtual reality driving simulator seem to you?" and "How much was your fear reduced?" In this study, we found that the difference in manipulation method (i.e., the patient group's hand control versus the normal driver's foot controls) does not seem to influence relative performance in the VR driving simulator, though training to improve the use of hand controls in the VR driving simulator would be useful to reduce the fear that the patients feel while driving.