Synagoge in Märkisch Friedland [Illustration] : Tür des Oraun Hakodesch

Scan von Monochrom-Mikroform

Vor der Tür

Samuel Jakob Jmber

Sēfer Ḥiddûšê tôrā : we-ze šemô ašer yiqre'û lô Berît Šālôm û-vô derûšîm neḥmādîm ...

ašer îzzēn ḥîbbēr we-tîqqēn ... Pinḥās .... Ben- ... Pelṭā

Miqrâ Tôrã, nevî'îm u-_ketûvîm : enthaltend: Den heiligen Urtext, die deutsche Übertragung, die allgemeine, ausführliche Erläuterung mit mehr als 500 englischen Holzschnitten

hrsg. von Ludwig Philippson

Ms. lat. qu. 15 - De technica microcosmi historia T. II, Tr. 1, Sect. 2, Port. 1-7

Vorbesitzer: Johann Maximilian Zum Jungen

Pe͏̈tr I. Cajkowskij, Brustbild

Signatur des Originals: S 36/F06903

Alexander Siloti, Pe͏̈tr I. Cajkovskij, Doppelbildnis, Brustbild

Signatur des Originals: S 36/F09901

Pe͏̈tr I. Čajkowskij, Kniestück

Signatur des Originals: S 36/F10091

{[N.N.], Szenenfoto, Gruppenbildnis, in: Pe͏̈tr Il Čajkowskij: Jolanthe, Frankfurt a. M.: Opernhaus, ca. 1901

Signatur des Originals: S 36/F11996

Role and regulation of c-KIT gene expression in tumor growth and metastasis of human melanoma

The purpose of this study was to investigate the role of the c-KIT receptor in the progression of human melanoma and the mechanism(s) for the regulation of c-KIT gene expression in human melanoma.^ The molecular changes associated with the transition of melanoma cells from radial growth phase (RGP) to vertical growth phase (VGP) (metastatic phenotype) are not well-defined. Expression of the tyrosine-kinase receptor c-KIT progressively decreases during local tumor growth and invasion of human melanomas. To provide direct evidence that the metastasis of human melanoma is associated with the loss of c-KIT expression, highly metastatic A375SM cells, which express very low or undetectable levels of c-KIT, were tranduced with the human c-KIT gene. We demonstrated that enforced c-KIT expression in highly metastatic human melanoma cells significantly suppressed their tumorigenicity and metastatic propensity in nude mice. In addition, we showed that the ligand for c-KIT, SCF, induces apoptosis in human melanoma cells expressing c-KIT under both in vitro and in vivo conditions. These results suggest that loss of c-KIT receptor may allow malignant melanoma cells to escape SCF/c-KIT-mediated apoptosis, thus contributing to tumor growth and eventually metastasis.^ Furthermore, we investigated the possible mechanism(s) for the down-regulation of c-KIT gene expression in malignant melanoma. Sequence analysis of the c-KIT promoter indicated that this promoter contains several consensus binding-site sequences including three putative AP2 and two Myb sites. Although Myb was shown to be associated with c-KIT expression in human hemotopoietic cells, we found no correlation between c-KIT expression and Myb expression in human melanoma cell lines. In contrast, we showed that c-KIT expression directly correlates with expression of AP2 in human melanoma cells. We found that highly metastatic cells do not express the transcription factor AP2. Expression of AP2 in A375SM cells (c-KIT-negative and AP2-negative) was enough to restore luciferase activity driven by the c-KIT promoter in a dose-dependent manner. On the other hand, co-expression of the dominant-negative form of AP2 (AP2B) in Mel-501 cells (c-KIT-positive and AP2-positive) resulted in two-fold reduction in luciferase activity. Electrophoretic mobility shift assays revealed that the c-KIT promoter contains functional AP2 binding sites which could associate with AP2 protein. Endogenous c-KIT gene expression levels were elevated in AP2 stably-transfected human melanoma A375SM cells. Expression of exogenous AP2 in A375SM cells inhibited their tumorigenicity and metastatic potential in nude mice. The c-KIT ligand, SCF, also induced apoptosis in the AP2 stably-transfected A375SM cells. The identification of AP2 as an important regulator for c-KIT expression suggests that AP2 may have tumor growth and metastasis inhibitory properties, possibly mediated through c-KIT/SCF effects on apoptosis of human melanoma cells. Since AP2 binding sites were found in the promoters of other genes involved in the progression of human melanoma, such as MMP2 (72 kDa collagenase), MCAM/MUC18 and P21/WAF-1, our findings suggest that loss of AP2 expression might be a crucial event in the development of malignant melanoma. ^