@article{AdamBaeurleBrodskyetal.2014, author = {Adam, Christian and Baeurle, Anne and Brodsky, Jeffrey L. and Schrama, David and Wipf, Peter and Becker, J{\"u}rgen Christian and Houben, Roland}, title = {The HSP70 Modulator MAL3-101 Inhibits Merkel Cell Carcinoma}, doi = {10.1371/journal.pone.0092041}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112795}, year = {2014}, abstract = {Merkel Cell Carcinoma (MCC) is a rare and highly aggressive neuroendocrine skin cancer for which no effective treatment is available. MCC represents a human cancer with the best experimental evidence for a causal role of a polyoma virus. Large T antigens (LTA) encoded by polyoma viruses are oncoproteins, which are thought to require support of cellular heat shock protein 70 (HSP70) to exert their transforming activity. Here we evaluated the capability of MAL3-101, a synthetic HSP70 inhibitor, to limit proliferation and survival of various MCC cell lines. Remarkably, MAL3-101 treatment resulted in considerable apoptosis in 5 out of 7 MCC cell lines. While this effect was not associated with the viral status of the MCC cells, quantitative mRNA expression analysis of the known HSP70 isoforms revealed a significant correlation between MAL3-101 sensitivity and HSC70 expression, the most prominent isoform in all cell lines. Moreover, MAL3-101 also exhibited in vivo antitumor activity in an MCC xenograft model suggesting that this substance or related compounds are potential therapeutics for the treatment of MCC in the future.}, language = {en} } @article{HaferkampHesbacherWeyandtetal.2014, author = {Haferkamp, Sebastian and Hesbacher, Sonja and Weyandt, Gerhard and Vetter-Kauczok, Claudia S. and Becker, J{\"u}rgen C. and Motschenbacher, Stephanie and Wobser, Marion and Maier, Melissa and Schmid, Corinna P. and Houben, Roland}, title = {p53 regulation by TRP2 is not pervasive in melanoma}, doi = {10.1371/journal.pone.0087440}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111396}, year = {2014}, abstract = {p53 is a central tumor suppressor protein and its inhibition is believed to be a prerequisite for cancer development. In approximately 50\% of all malignancies this is achieved by inactivating mutations in the p53 gene. However, in several cancer entities, including melanoma, p53 mutations are rare. It has been recently proposed that tyrosinase related protein 2 (TRP2), a protein involved in melanin synthesis, may act as suppressor of the p53 pathway in melanoma. To scrutinize this notion we analyzed p53 and TRP2 expression by immunohistochemistry in 172 melanoma tissues and did not find any correlation. Furthermore, we applied three different TRP2 shRNAs to five melanoma cell lines and could not observe a target specific effect of the TRP2 knockdown on either p53 expression nor p53 reporter gene activity. Likewise, ectopic expression of TRP2 in a TRP2 negative melanoma cell line had no impact on p53 expression. In conclusion our data suggest that p53 repression critically controlled by TRP2 is not a general event in melanoma.}, language = {en} } @article{VamanVSPoppeHoubenetal.2015, author = {Vaman V. S., Anjana and Poppe, Heiko and Houben, Roland and Grunewald, Thomas G. P. and Goebeler, Matthias and Butt, Elke}, title = {LASP1, a Newly Identified Melanocytic Protein with a Possible Role in Melanin Release, but Not in Melanoma Progression}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {6}, doi = {10.1371/journal.pone.0129219}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125994}, pages = {e0129219}, year = {2015}, abstract = {The LIM and SH3 protein 1 (LASP1) is a focal adhesion protein. Its expression is increased in many malignant tumors. However, little is known about the physiological role of the protein. In the present study, we investigated the expression and function of LASP1 in normal skin, melanocytic nevi and malignant melanoma. In normal skin, a distinct LASP1 expression is visible only in the basal epidermal layer while in nevi LASP1 protein is detected in all melanocytes. Melanoma exhibit no increase in LASP1 mRNA compared to normal skin. In melanocytes, the protein is bound to dynamin and mainly localized at late melanosomes along the edges and at the tips of the cell. Knockdown of LASP1 results in increased melanin concentration in the cells. Collectively, we identified LASP1 as a hitherto unknown protein in melanocytes and as novel partner of dynamin in the physiological process of membrane constriction and melanosome vesicle release.}, language = {en} }