RESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMEN
MUC1-C overexpression has been associated with the progression of pancreatic tumors by promoting the aggressive and metastatic phenotypes. As MUC1 is a STAT3 target gene, STAT3 plays a major role in regulating MUC1-C expression. In this study, we report an alternative mechanism by which integrin-linked kinase (ILK) post-transcriptionally modulates the expression of MUC1-C by maintaining its protein stability in pancreatic cancer cells. We found that ILK acts in concert with STAT3 to facilitate IL-6-mediated upregulation of MUC1-C; ILK depletion was equally effective as STAT3 depletion in abolishing IL-6-induced MUC1-C overexpression without disturbing the phosphorylation or cellular distribution of STAT3. Conversely, ectopic expression of constitutively active ILK increased MUC1-C expression, though this increase was not noted with kinase-dead ILK. This finding suggests the requirement of the kinase activity of ILK in regulating MUC1-C stability, which was confirmed by using the ILK kinase inhibitor T315. Furthermore, our data suggest the involvement of protein kinase C (PKC)δ in mediating the suppressive effect of ILK inhibition on MUC1-C repression. For example, co-immunoprecipitation analysis indicated that ILK depletion-mediated MUC1-C phosphorylation was accompanied by increased phosphorylation of PKCδ at the activation loop Thr-507 and increased binding of PKCδ to MUC1-C. Conversely, ILK overexpression resulted in decreased PKCδ phosphorylation. From a mechanistic perspective, the present finding, together with our recent report that ILK controls the expression of oncogenic KRAS through a regulatory loop, underscores the pivotal role of ILK in promoting pancreatic cancer progression.
RESUMEN
The increasing clinical use of acyclovir, ganciclovir, and foscarnet against herpes simplex virus (HSV), varicella-zoster virus, and cytomegalovirus has been associated with the emergence of drug-resistant herpesvirus strains. To develop anti-HSV compounds from plants, 31 herbs used as antipyretic and anti-inflammatory agents in Chinese medicine were screened. Five different preparations (cold aqueous, hot aqueous, ethanolic, acid ethanolic, and methanolic) from 31 herbs were analyzed by plaque reduction assay, and 7 extracts. which showed significant antiviral activities, were further elucidated for their antiviral mechanisms. Our results showed that ethanolic extract of Rheum officinale and methanolic extract of Paeonia suffruticosa prevented the process of virus attachment and penetration. Aqueous extract of P. suffruticosa and ethanolic extract of Melia toosendan inhibited virus attachment to cell surface. Aqueous extract of Sophora flavescens and methanolic extract of M. toosendan showed no effect on virus attachment and penetration. These data indicated that these 4 herbs have a potential value as a source of new powerful anti-HSV compounds.