TY  - JOUR
A1  - Meinert, Madlen
A1  - Jessen, Christina
A1  - Hufnagel, Anita
A1  - Kreß, Julia Katharina Charlotte
A1  - Burnworth, Mychal
A1  - Däubler, Theo
A1  - Gallasch, Till
A1  - Da Xavier Silva, Thamara Nishida
A1  - Dos Santos, Ancély Ferreira
A1  - Ade, Carsten Patrick
A1  - Schmitz, Werner
A1  - Kneitz, Susanne
A1  - Friedmann Angeli, José Pedro
A1  - Meierjohann, Svenja
T1  - Thiol starvation triggers melanoma state switching in an ATF4 and NRF2-dependent manner
JF  - Redox Biology
N2  - The cystine/glutamate antiporter xCT is an important source of cysteine for cancer cells. Once taken up, cystine is reduced to cysteine and serves as a building block for the synthesis of glutathione, which efficiently protects cells from oxidative damage and prevents ferroptosis. As melanomas are particularly exposed to several sources of oxidative stress, we investigated the biological role of cysteine and glutathione supply by xCT in melanoma. xCT activity was abolished by genetic depletion in the Tyr::CreER; Braf\(^{CA}\); Pten\(^{lox/+}\) melanoma model and by acute cystine withdrawal in melanoma cell lines. Both interventions profoundly impacted melanoma glutathione levels, but they were surprisingly well tolerated by murine melanomas in vivo and by most human melanoma cell lines in vitro. RNA sequencing of human melanoma cells revealed a strong adaptive upregulation of NRF2 and ATF4 pathways, which orchestrated the compensatory upregulation of genes involved in antioxidant defence and de novo cysteine biosynthesis. In addition, the joint activation of ATF4 and NRF2 triggered a phenotypic switch characterized by a reduction of differentiation genes and induction of pro-invasive features, which was also observed after erastin treatment or the inhibition of glutathione synthesis. NRF2 alone was capable of inducing the phenotypic switch in a transient manner. Together, our data show that cystine or glutathione levels regulate the phenotypic plasticity of melanoma cells by elevating ATF4 and NRF2.
KW  - thiol starvation
KW  - ATF4
KW  - NRF2
KW  - melanoma
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350328
VL  - 70
ER  - 
TY  - JOUR
A1  - Kang, Ji Hyoun
A1  - Manousaki, Tereza
A1  - Franchini, Paolo
A1  - Kneitz, Susanne
A1  - Schartl, Manfred
A1  - Meyer, Axel
T1  - Transcriptomics of two evolutionary novelties: how to make a sperm-transfer organ out of an anal fin and a sexually selected "sword" out of a caudal fin
JF  - Ecology and Evolution
N2  - Swords are exaggerated male ornaments of swordtail fishes that have been of great interest to evolutionary biologists ever since Darwin described them in the Descent of Man (1871). They are a novel sexually selected trait derived from modified ventral caudal fin rays and are only found in the genus Xiphophorus. Another phylogenetically more widespread and older male trait is the gonopodium, an intromittent organ found in all poeciliid fishes, that is derived from a modified anal fin. Despite many evolutionary and behavioral studies on both traits, little is known so far about the molecular mechanisms underlying their development. By investigating transcriptomic changes (utilizing a RNA-Seq approach) in response to testosterone treatment in the swordtail fish, Xiphophorus hellerii, we aimed to better understand the architecture of the gene regulatory networks underpinning the development of these two evolutionary novelties. Large numbers of genes with tissue-specific expression patterns were identified. Among the sword genes those involved in embryonic organ development, sexual character development and coloration were highly expressed, while in the gonopodium rather more morphogenesis-related genes were found. Interestingly, many genes and genetic pathways are shared between both developing novel traits derived from median fins: the sword and the gonopodium. Our analyses show that a larger set of gene networks was co-opted during the development and evolution of the older gonopodium than in the younger, and morphologically less complex trait, the sword. We provide a catalog of candidate genes for future efforts to dissect the development of those sexually selected exaggerated male traits in swordtails.
KW  - mouse testis differentiation
KW  - fishes Xiphophorus
KW  - beetle horns
KW  - gonopodium
KW  - RNA-Seq
KW  - swordtails
KW  - Xiphophorus
KW  - key innovation
KW  - male-specific traits
KW  - Co-option
KW  - genus Xiphophorus
KW  - hybrid origin
KW  - Drosophila melanogaster
KW  - expression analysis
KW  - cell proliferation
KW  - preexisting bias
KW  - sex combs
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-144139
VL  - 5
IS  - 4
ER  -