Serine/Threonine Kinase 17A is a Novel Candidate for Therapeutic Targeting in Glioblastoma

STK17A is a relatively uncharacterized member of the death-associated protein family of serine/threonine kinases which have previously been associated with cell death and apoptosis. Our prior work established that STK17A is a novel p53 target gene that is induced by a variety of DNA damaging agents in a p53-dependent manner. In this study we have uncovered an additional, unanticipated role for STK17A as a candidate promoter of cell proliferation and survival in glioblastoma (GBM). Unexpectedly, it was found that STK17A is highly overexpressed in a grade-dependent manner in gliomas compared to normal brain and other cancer cell types with the highest level of expression in GBM. Knockdown of STK17A in GBM cells results in a dramatic alteration in cell shape that is associated with decreased proliferation, clonogenicity, migration, invasion and anchorage independent colony formation. STK17A knockdown also sensitizes GBM cells to genotoxic stress. STK17A overexpression is associated with a significant survival disadvantage among patients with glioma which is independent of age, molecular phenotype, IDH1 mutation, PTEN loss, and alterations in the p53 pathway and partially independent of grade. In summary, we demonstrate that STK17A provides a proliferative and survival advantage to GBM cells and is a potential target to be exploited therapeutically in patients with glioma

Effect of Rising Temperature on Lyme Disease: Ixodes scapularis Population Dynamics and Borrelia burgdorferi Transmission and Prevalence

Warmer temperatures are expected to increase the incidence of Lyme disease through enhanced tick maturation rates and a longer season of transmission. In addition, there could be an increased risk of disease export because of infected mobile hosts, usually birds. A temperature-driven seasonal model of Borrelia burgdorferi (Lyme disease) transmission among four host types is constructed as a system of nonlinear ordinary differential equations. The model is developed and parametrized based on a collection of lab and field studies. The model is shown to produce biologically reasonable results for both the tick vector (Ixodes scapularis) and the hosts when compared to a different set of studies. The model is used to predict the response of Lyme disease risk to a mean annual temperature increase, based on current temperature cycles in Hanover, NH. Many of the risk measures suggested by the literature are shown to change with increased mean annual temperature. The most straightforward measure of disease risk is the abundance of infected questing ticks, averaged over a year. Compared to this measure, which is difficult and resource-intensive to track in the field, all other risk measures considered underestimate the rise of risk with rise in mean annual temperature. The measure coming closest was “degree days above zero.” Disease prevalence in ticks and hosts showed less increase with rising temperature. Single field measurements at the height of transmission season did not show much change at all with rising temperature

Serine/Threonine Kinase 17A Is a Novel Candidate for Therapeutic Targeting in Glioblastoma

<div><p>STK17A is a relatively uncharacterized member of the death-associated protein family of serine/threonine kinases which have previously been associated with cell death and apoptosis. Our prior work established that STK17A is a novel p53 target gene that is induced by a variety of DNA damaging agents in a p53-dependent manner. In this study we have uncovered an additional, unanticipated role for STK17A as a candidate promoter of cell proliferation and survival in glioblastoma (GBM). Unexpectedly, it was found that STK17A is highly overexpressed in a grade-dependent manner in gliomas compared to normal brain and other cancer cell types with the highest level of expression in GBM. Knockdown of STK17A in GBM cells results in a dramatic alteration in cell shape that is associated with decreased proliferation, clonogenicity, migration, invasion and anchorage independent colony formation. STK17A knockdown also sensitizes GBM cells to genotoxic stress. STK17A overexpression is associated with a significant survival disadvantage among patients with glioma which is independent of age, molecular phenotype, IDH1 mutation, PTEN loss, and alterations in the p53 pathway and partially independent of grade. In summary, we demonstrate that STK17A provides a proliferative and survival advantage to GBM cells and is a potential target to be exploited therapeutically in patients with glioma. </p> </div

STK17A knockdown decreases oncogenic properties of GBM cells.

<p><b>A</b>, STK17A knockdown decreases soft agar colony formation. U87 control or U87 STK17A knockdown cells were suspended in soft agar and cells were stained with MTT reagent after 2 weeks of culture. Representative of two independent experiments. <b>B</b>, STK17A knockdown decreases clonogenicity of GBM cells. U87 control or STK17A U87 knockdown cells were plated and stained with Giemsa after 10 days of cell culture. Representative of three independent experiments. <b>C</b>, STK17A knockdown sensitizes GBM cells to cisplatin and temozolomide. Left, Dose response after 3 days of cisplatin treatment of U87 or U251 control versus STK17A knockdown cells. Cell proliferation and survival was measured with Cell-Titer Glo reagent. Data points are the average of biological triplicates and error bars are SD. *, p < 0.05. Representative of three independent experiments. Right, Dose response after 3 days of temozolomide treatment of U87 control versus U87 STK17A knockdown cells. Cell proliferation and survival was measured with Cell-Titer Glo reagent. Data points are the average of biological triplicates and error bars are SD. *, p< 0.05. Representative of two independent experiments. </p

STK17A knockdown results in the formation of actin stress fibers and inhibition of cell motility and invasion.

<p><b>A</b>, Representative fluorescent images of U87 cells stably expressing control shRNA and two distinct STK17A shRNAs. Actin is stained green and nuclei are stained blue. Note the larger size of STK17A knockdown cells and the presence of actin stress fibers. Extent of knockdown is depicted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081803#pone-0081803-g003" target="_blank">Figure 3</a>. This morphologic phenotype was apparent in independent derivations of the cell lines. Pictures were taken at 20X magnification on a NIKON ELWD fluorescent microscope. <b>B</b>, STK17A knockdown decreases cell migration and invasion of U87 cells. Cell migration and invasion was assessed as described in Methods. Bars are the average of biological triplicates and error bars are SD. *, p < 0.05. Representative of two independent experiments.</p

STK17A expression in glioma is associated with high grade and decreased survival.

<p><b>A</b>, Expression data was downloaded from the Rembrandt and TCGA databases and data from Sun Brain [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081803#B19" target="_blank">19</a>] was downloaded from Oncomine and grouped according to grade. Rembrandt has 21 normal, 99 grade II, 85 grade III and 130 grade IV samples. TCGA has 10 normal, 7 grade II, 20 grade III and 482 grade IV samples and Sun Brain has 26 normal, 45 grade II, 31 grade III and 81 grade IV samples. Error bars are SEM. *, p < 0.02. <b>B</b>, STK17A expression is associated with poor overall survival in gliomas. Kaplan-Meier log-rank tests were performed on data obtained from the TCGA database. In all cases high and low expressing groups were divided at the median. All glioma and low grade glioma expression was from RNA-seq data while GBM expression was from Affymetrix microarray data. </p