作者: Poss, Kenneth D. ; Pugach, Emily K. ; Storer, Narie Y. ; Hettmer, Simone ; Chen, Eleanor Y. ; DiBiase, Antony ; Langenau, David M. ; Liu, Jianing ; Wagers, Amy J. ; Ignatius, Myron S. ; Wills, Airon A. ; Zon, Leonard I. ; Le, Xiuning

The zebrafish is a powerful genetic model that has only recently been used to dissect developmental pathways involved in oncogenesis. We hypothesized that operative pathways during embryogenesis would also be used for oncogenesis. In an effort to define RAS target genes during embryogenesis, gene expression was evaluated in Tg(hsp70-HRASG12V) zebrafish embryos subjected to heat shock. dusp6 was activated by RAS, and this was used as the basis for a chemical genetic screen to identify small molecules that interfere with RAS signaling during embryogenesis. A KRASG12D-induced zebrafish embryonal rhabdomyosarcoma was then used to assess the therapeutic effects of the small molecules. Two of these inhibitors, PD98059 and TPCK, had anti-tumor activity as single agents in both zebrafish embryonal rhabdomyosarcoma and a human cell line of rhabdomyosarcoma that harbored activated mutations in NRAS. PD98059 inhibited MEK1 whereas TPCK suppressed S6K1 activity; however, the combined treatment completely suppressed eIF4B phosphorylation and decreased translation initiation. Our work demonstrates that the activated pathways in RAS induction during embryogenesis are also important in oncogenesis and that inhibition of these pathways suppresses tumor growth.

2012-01-01·The International Journal of Developmental Biology4区 · 生物学

Characterization of proteolytic activities during intestinal regeneration of the sea cucumber, Holothuria glaberrima

4区 · 生物学

Article

作者: Consuelo Pasten ; José E. García-Arrarás ; Rey Rosa ; Sebastián González ; Stephanie Ortiz

Proteolysis carried out by different proteases control cellular processes during development and regeneration. Here we investigated the function of the proteasome and other proteases in the process of intestinal regeneration using as a model the sea cucumber Holothuria glaberrima. This echinoderm possesses the ability to regenerate its viscera after a process of evisceration. Enzymatic activity assays showed that intestinal extracts at different stages of regeneration possessed chymotrypsin-like activity. This activity was inhibited by i) MG132, a reversible inhibitor of chymotrypsin and peptidylglutamyl peptidase hydrolase (PGPH) activities of the proteasome, ii) E64d, a permeable inhibitor of cysteine proteases and iii) TPCK, a serine chymotrypsin inhibitor, but not by epoxomicin, an irreversible and potent inhibitor of all enzymatic activities of the proteasome. To elucidate the role which these proteases might play during intestinal regeneration, we carried out in vivo experiments injecting MG132, E64d and TPCK into regenerating animals. The results showed effects on the size of the regenerating intestine, cell proliferation and collagen degradation. These findings suggest that proteolysis by several proteases is important in the regulation of intestinal regeneration in H. glaberrima.

2009-08-01·Journal of Cellular Physiology2区 · 生物学

Glial cell‐derived neurotrophic factor increases migration of human chondrosarcoma cells via ERK and NF‐κB pathways

2区 · 生物学

Article

作者: Chih Hsin Tang ; Chun Yin Huang ; Yi Chin Fong ; Chen Ming Su ; Hsien Te Chen ; Chin Jung Hsu ; Wen-Pei Tseng ; Dah Yuu Lu ; Yi Chang Su ; Wei Hung Yang ; Shu Ning Yang

AbstractInvasion of tumor cells is the primary cause of therapeutic failure in the treatment of malignant chondrosarcomas. Glial cell‐derived neurotrophic factor (GDNF) plays a crucial role in migration and metastasis of human cancer cells. Integrins are the major adhesive molecules in mammalian cells. Here we found that GDNF directed the migration and increased cell surface expression of αv and β3 integrin in human chondrosarcoma cells. Pretreated of JJ012 cells with MAPK kinase (MEK) inhibitors PD98059 or U0126 inhibited the GDNF‐mediated migration and integrin expression. Stimulation of cells with GDNF increased the phosphorylation of MEK and extracellular signal‐regulating kinase (ERK). In addition, NF‐κB inhibitor (PDTC) or IκB protease inhibitor (TPCK) also inhibited GDNF‐mediated cells migration and integrin up‐regulation. Stimulation of cells with GDNF induced IκB kinase (IKKα/β) phosphorylation, IκB phosphorylation, p65 Ser536 phosphorylation, and κB‐luciferase activity. Furthermore, the GDNF‐mediated increasing of κB‐luciferase activity was inhibited by PD98059, U0126, PDTC and TPCK or MEK, ERK, IKKα, and IKKβ mutants. Taken together, these results suggest that the GDNF acts through MEK/ERK, which in turn activates IKKα/β and NF‐κB, resulting in the activations of αvβ3 integrin and contributing the migration of human chondrosarcoma cells. J. Cell. Physiol. 220: 499–507, 2009. © 2009 Wiley‐Liss, Inc.

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