Antitumor effects of a combined 5-aza-2'deoxycytidine and valproic acid treatment on rhabdomyosarcoma and medulloblastoma in Ptch mutant mice.

Patched (Ptch) heterozygous mice develop medulloblastoma (MB) and rhabdomyosarcoma (RMS) resembling the corresponding human tumors. We have previously shown that epigenetic silencing of the intact Ptch allele contributes to tumor formation in this model. Here, we investigated whether targeting of epigenetic silencing mechanisms could be useful in the treatment of Ptch-associated cancers.

Cyclopamine treatment of full-blown Hh/Ptch-associated RMS partially inhibits Hh/Ptch signaling, but not tumor growth.

Mutations in the Hedgehog (Hh) receptor Patched (Ptch) are responsible for a variety of tumors, which show ligand-independent stimulation of the Hh/Ptch signaling cascade. Cyclopamine is an alkaloid of the corn lily Veratrum californicum, which blocks activity of the pathway by inhibition of Smoothened (Smo), the signal transduction partner of Ptch. This results in growth inhibition of Hh/Ptch-dependent tumor cells in vitro, of subcutaneous xenografts as well as of precancerous lesions in Ptch(+/-) mice.

Gene transfer of cyto-protective molecules in corneal endothelial cells and cultured corneas: analysis of protective effects in vitro and in vivo.

The loss of corneal endothelial cells plays a critical role in many corneal diseases and is a common phenomenon following cornea transplantation. In addition, the non-regenerative capacity of human corneal endothelial cells (HCEC) ultimately requires appropriate protection of corneal tissues during ex vivo storage to ensure vitality of the cells. However, only 70% of donor corneas can be used for grafting because of endothelial deficiencies.