Genetic deletion of hspa8 leads to selective tissue malformations in zebrafish embryonic development.

The heat shock cognate 71 kDa protein HSPA8 (also known as HSC70), a constitutively expressed cognate member of the heat shock protein 70 family, plays an essential role in protein quality control and cell homeostasis maintenance. HSPA8 has been implicated in many diseases, including cancers and neurodegenerative diseases. Owing to massive cell death after knockdown of HSPA8 and nonviable Hspa8 knockout mice, the physiological role of HSPA8 in vertebrates and its underlying mechanisms of action have not yet been elucidated. To address this issue, we used CRISPR/Cas9 technology and genetically deleted hspa8 in zebrafish embryos. Genetic deletion of hspa8 resulted in malformations of the pharyngeal arches, pectoral fins, head and eyes at the later stages. We next focused on pharyngeal arch deficiency and found that pharyngeal arches in hspa8 mutant embryos exhibited induction of endoplasmic reticulum stress and activation of the unfolded protein response via the Perk/p-eIF2α/Atf4 signaling cascade. Inhibition of Perk/p-eIF2α/Atf4 signaling rescued the developmental deficiency of pharyngeal arches caused by depletion of Hspa8. Taken together, our results provide novel insights into the tissue-specific roles of Hspa8 in the regulation of vertebrate embryonic development.

Microwave-assisted synthesis and biological evaluation of 3,4-diaryl maleic anhydride/N-substituted maleimide derivatives as combretastatin A-4 analogues.

A series of new CA-4 analogues bearing maleic anhydride/N-substituted maleimide moiety were synthesized via a microwave-assisted process. They were evaluated for the anti-proliferative activities against three tumor cell lines (SGC-7901, HT-1080 and KB). Most compounds showed moderate potencies in micromolar range, with the most promising analogue 6f showing active at submicromolar concentration against HT-1080 cancer cells which was selected to investigate the antitumor mechanisms. In addition, molecular docking studies within the colchicine binding site of tubulin were also in good agreement with the tubulin polymerization inhibitory data and provided a basis for further structure-guided design of novel CA-4 analogues.

Synthesis and evaluation of benzimidazole carbamates bearing indole moieties for antiproliferative and antitubulin activities.

A series of novel benzimidazole carbamates bearing indole moieties with sulphur or selenium atoms connecting the aromatic rings were synthesised and evaluated for their antiproliferative activities against three human cancer cell lines (SGC-7901, A-549 and HT-1080) using an MTT assay. Compounds 10a, 10b, 7a, 7b and 7f showed significant activities against these cell lines. The most potent compound in this series, 10a, was selected to investigate its antitumour mechanism. In addition, molecular docking studies suggested that compound 10a interacts very closely with the nocodazole docking pose through hydrogen bonds at the colchicine binding site of tubulin.