Abnormal activation of the hedgehog-signaling pathway is the pivotal abnormality driving the growth of basal cell carcinomas (BCCs), the most common type of human cancer. Antagonists of this pathway such as cyclopamine may therefore be useful for treatment of basal cell carcinomas and other hedgehog-driven tumors. We report here that chronic oral administration of cyclopamine dramatically reduces (ϳ66%) UVBinduced basal cell carcinoma formation in Ptch1 ؉/؊ mice. Fas expression is low in human and murine basal cell carcinomas but is up-regulated in the presence of the smoothened (SMO) antagonist, cyclopamine, both in vitro in the mouse basal cell carcinoma cell line ASZ001 and in vivo after acute treatment of mice with basal cell carcinomas. This parallels an elevated rate of apoptosis. Conversely, expression of activated SMO in C3H10T1/2 cells inhibits Fas expression. Fas/Fas ligand interactions are necessary for cyclopamine-mediated apoptosis in these cells, a process involving caspase-8 activation. Our data provide strong evidence that cyclopamine and perhaps other SMO antagonists are potent in vivo inhibitors of UVB-induced basal cell carcinomas in Ptch1 ؉/؊ mice and likely in humans because the majority of human basal cell carcinomas manifest mutations in PTCH1 and that a major mechanism of their inhibitory effect is through up-regulation of Fas, which augments apoptosis.

Mutations in the maize gene sugary2 ( su2 ) affect starch structure and its resultant physiochemical properties in useful ways, although the gene has not been characterized previously at the molecular level. This study tested the hypothesis that su2 codes for starch synthase IIa (SSIIa). Two independent mutations of the su2 locus, su2-2279 and su2-5178 , were identified in a Mutator -active maize population. The nucleotide sequence of the genomic locus that codes for SSIIa was compared between wild type plants and those homozygous for either novel mutation. Plants bearing su2-2279 invariably contained a Mutator transposon in exon 3 of the SSIIa gene, and su2-5178 mutants always contained a small retrotransposon-like insertion in exon 10. Six allelic su2 (-) mutations conditioned loss or reduction in abundance of the SSIIa protein detected by immunoblot. These data indicate that su2 codes for SSIIa and that deficiency in this isoform is ultimately responsible for the altered physiochemical properties of su2 (-) mutant starches. A specific starch synthase isoform among several identified in soluble endosperm extracts was absent in su2-2279 or su2-5178 mutants, indicating that SSIIa is active in the soluble phase during kernel development. The immediate structural effect of the su2 (-) mutations was shown to be increased abundance of short glucan chains in amylopectin and a proportional decrease in intermediate length chains, similar to the effects of SSII deficiency in other species.

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The hedgehog (Hh) pathway plays a critical role during development of embryos and cancer. Although the molecular basis by which protein kinase A (PKA) regulates the stability of hedgehog downstream transcription factor cubitus interruptus, the Drosophila homologue of vertebrate Gli molecules, is well documented, the mechanism by which PKA inhibits the functions of Gli molecules in vertebrates remains elusive. Here, we report that activation of PKA retains Gli1 in the cytoplasm. Conversely, inhibition of PKA activity promotes nuclear accumulation of Gli1. Mutation analysis identifies Thr 374 as a major PKA site determining Gli1 protein localization. In the three-dimensional structure, Thr 374 resides adjacent to the basic residue cluster of the nuclear localization signal (NLS). Phosphorylation of this Thr residue is predicted to alter the local charge and consequently the NLS function. Indeed, mutation of this residue to Asp (Gli1/T374D) results in more cytoplasmic Gli1 whereas a mutation to Lys (Gli1/T374K) leads to more nuclear Gli1. Disruption of the NLS causes Gli1/T374K to be more cytoplasmic. We find that the change of Gli1 localization is correlated with the change of its transcriptional activity. These data provide evidence to support a model that PKA regulates Gli1 localization and its transcriptional activity, in part, through modulating the NLS function.

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Segmented polyether-polyurethane (PU)/montmorillonite nanocomposites have been synthesized with poly(tetramethylene glycol), 4,4-diphenylmethane diisocyanate, propylenediamine, and montmorillonite. The nanoscale silicate layers are intercalated or exfoliated in the PU matrix, which are characterized by X-ray diffraction pattern and transmission electron microscopy. The PU/montmorillonite composites have been investigated by FT-IR dichroism during the stretching process in order to study the hard and soft chain orientation, hydrogen bonding, and strain induced by crystallization of the soft segment chains in PU. DSC experiment indicates that the soft phase Tg increases with the montmorillonite content. The mechanical analysis showed that tensile strength,Young's modulus, and elongation at break increase markedly, 1700% elongation at break for the composite containing 2.0 wt % montmorillonite.

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A two-step sequential blade-coating process in air to fabricate high-efficiency perovskite solar cells and modules.