Rapid modifications of N-substitution in iminosugars: development of new ß-glucocerebrosidase inhibitors and pharmacological chaperones for Gaucher disease.

The rapid discovery of ß-glucocerebrosidase (GCase) inhibitors and pharmacological chaperones for Gaucher disease is described. The N-aminobutyl DNJ-based iminosugar was synthesized and conjugating with a variety of carboxylic acids to generate a N-diversely substituted iminosugar-based library. Several members of this library were found to be nanomolar-range inhibitors of GCase; the inhibition constant Ki of the most potent was found to be 71nM. Although these new molecules showed reasonable chaperoning activity (1.5- to 1.9-fold) in the N370S fibroblast of Gaucher patient-derived cell line, this was accompanies by a concomitant decrease in the cellular α-glucosidase activity, which might limit their further therapeutic potential. Next, newly developed N-substituents were assembled with pyrrolidine-based scaffolds to generate new molecules for further evaluation. The new 2,5-dideoxy-2,5-imino-d-mannitol (DMDP)-based iminosugar 22 was found to exhibit a satisfactory chaperoning activity to enhance GCase activity by 2.2-fold in Gaucher N370S cell line, without impairment of cellular α-glucosidase activity.

Taiwan cobra cardiotoxin III inhibits Src kinase leading to apoptosis and cell cycle arrest of oral squamous cell carcinoma Ca9-22 cells.

Cardiotoxin III (CTX III), a basic polypeptide with 60-amino acid residues isolated from Naja naja atra venom, has been reported to have cytotoxic activity. CTX III exerted cytotoxicity with the S-phase cell cycle arrest, correlated with a marked decrease in the expression levels of cyclin A, cyclin B, and cyclin-dependent kinase 1 (CDK1), and apoptosis, accompanied with Bax and Bad up-regulation, and the down-regulation of Bcl-2, p-Bad, and X-linked inhibitor of apoptosis (XIAP) with cytochrome c release and sequential activation of caspase-9 and caspase-3 in Ca9-22 cells. Mechanistic studies showed that CTX III suppressed the phosphorylation of Src, EGFR, STAT3, STAT5, Akt, and activation of PI3 K (p110). Moreover, Src inactivation was observed earlier than that of the EGFR and the Src inhibitor PP2 suppressed the levels of phospho-EGFR, phospho-STAT3, phospho-STAT5, phospho-Akt, and PI3 K(p110). The PP2 also caused the S-phase arrest and apoptosis, and led to down-regulation of Bcl-2, p-Bad, XIAP, cyclin A, cyclin B, and CDK1, and up-regulation of Bax and Bad, similar to that observed in CTX III treatment. Taken together, these results indicate that CTX III induces apoptosis and S-phase arrest in Ca9-22 cells via concomitant inactivation of the Src, EGFR, STAT3, STAT5, PI3 K(p110), and Akt signaling pathways.

Rough eye is a gain-of-function allele of amos that disrupts regulation of the proneural gene atonal during Drosophila retinal differentiation.

The regular organization of the ommatidial lattice in the Drosophila eye originates in the precise regulation of the proneural gene atonal (ato), which is responsible for the specification of the ommatidial founder cells R8. Here we show that Rough eye (Roi), a dominant mutation manifested by severe roughening of the adult eye surface, causes defects in ommatidial assembly and ommatidial spacing. The ommatidial spacing defect can be ascribed to the irregular distribution of R8 cells caused by a disruption of the patterning of ato expression. Disruptions in the recruitment of other photoreceptors and excess Hedgehog production in differentiating cells may further contribute to the defects in ommatidial assembly. Our molecular characterization of the Roi locus demonstrates that it is a gain-of-function mutation of the bHLH gene amos that results from a chromosomal inversion. We show that Roi can rescue the retinal developmental defect of ato1 mutants and speculate that amos substitutes for some of ato's function in the eye or activates a residual function of the ato1 allele.