AR-A 014418 Used against GSK3beta Downregulates Expression of hnRNPA1 and SF2/ASF Splicing Factors

Glioblastoma is one of the most aggressive forms of primary brain tumors of glial cells, including aberrant regulation of glycogen synthase kinase 3 β (GSK3 β ) and splicing factors deregulation. Here, we investigate the role of small molecule AR-A014418 and Manzamine A against GSK3 kinase with factual control on splicing regulators. AR-A 014418, 48 hrs posttreatment, caused dose (25-100  μ M) dependent inhibition in U373 and U87 cell viability with also inhibition in activating tyrosine phosphorylation of GSK3alpha (Tyr 279) and beta (Tyr 216). Furthermore, inhibition of GSK3 kinase resulted in significant downregulation of splicing factors (SRSF1, SRSF5, PTPB1, and hnRNP) in U87 cells with downregulation of antiapoptotic genes such as BCL2, BCL-xL, Survivin, MCL1, and BMI1. Similarly, downregulation of splicing factors was also observed in U373 glioma cell after using SiRNA against AKT and GSK3beta kinase. In addition, potential roles of AR-A014418 in downregulation of splicing factors were reflected with decrease in Anxa7 (VA) variant and increase in Anxa7 WT tumor suppressor transcript and protein. The above results suggest that inhibition of GSK3beta kinase activation could be the beneficial strategy to inhibit the occurrence of alternative cancer escape pathway via downregulating the expression of splicing regulators as well as apoptosis.