TY  - JOUR
A1  - Leikam, C
A1  - Hufnagel, AL
A1  - Otto, C
A1  - Murphy, DJ
A1  - Mühling, B
A1  - Kneitz, S
A1  - Nanda, I
A1  - Schmid, M
A1  - Wagner, TU
A1  - Haferkamp, S
A1  - Bröcker, E-B
A1  - Schartl, M
A1  - Meierjohann, S
T1  - In vitro evidence for senescent multinucleated melanocytes as a source for tumor-initiating cells
JF  - Cell Death and Disease
N2  - Oncogenic signaling in melanocytes results in oncogene-induced senescence (OIS), a stable cell-cycle arrest frequently characterized by a bi-or multinuclear phenotype that is considered as a barrier to cancer progression. However, the long-sustained conviction that senescence is a truly irreversible process has recently been challenged. Still, it is not known whether cells driven into OIS can progress to cancer and thereby pose a potential threat. Here, we show that prolonged expression of the melanoma oncogene N-RAS\(^{61K}\) in pigment cells overcomes OIS by triggering the emergence of tumor-initiating mononucleated stem-like cells from senescent cells. This progeny is dedifferentiated, highly proliferative, anoikis-resistant and induces fast growing, metastatic tumors. Our data describe that differentiated cells, which are driven into senescence by an oncogene, use this senescence state as trigger for tumor transformation, giving rise to highly aggressive tumor-initiating cells. These observations provide the first experimental in vitro evidence for the evasion of OIS on the cellular level and ensuing transformation.
KW  - reactive oxygen
KW  - human melanoma
KW  - MITF
KW  - cancer
KW  - skin
KW  - DNA damage
KW  - kappa-B
KW  - oncogene-induced senescence
KW  - cellular senescence
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148718
VL  - 6
IS  - e1711
ER  - 
TY  - JOUR
A1  - Martinez-Bengochea, A. L.
A1  - Kneitz, S.
A1  - Herpin, A.
A1  - Nobrega, R. H.
A1  - Adolfi, M. C.
A1  - Schartl, M.
T1  - Sexual development dysgenesis in interspecific hybrids of Medaka fish
JF  - Scientific Reports
N2  - Fish are amongst vertebrates the group with the highest diversity of known sex-determining genes. Particularly, the genus Oryzias is a suitable taxon to understand how different sex determination genetic networks evolved in closely related species. Two closely related species, O. latipes and O. curvinotus, do not only share the same XX/XY sex chromosome system, but also the same male sex-determining gene, dmrt1bY. We performed whole mRNA transcriptomes and morphology analyses of the gonads of hybrids resulting from reciprocal crosses between O. latipes and O. curvinotus. XY male hybrids, presenting meiotic arrest and no production of sperm were sterile, and about 30% of the XY hybrids underwent male-to-female sex reversal. Both XX and XY hybrid females exhibited reduced fertility and developed ovotestis while aging. Transcriptome data showed that male-related genes are upregulated in the XX and XY female hybrids. The transcriptomes of both types of female and of the male gonads are characterized by upregulation of meiosis and germ cell differentiation genes. Differences in the parental species in the downstream pathways of sexual development could explain sex reversal, sterility, and the development of intersex gonads in the hybrids. We hypothesize that male-to-female sex reversal may be connected to a different development time between species at which dmrt1bY expression starts. Our results provide molecular clues for the proximate mechanisms of hybrid incompatibility and Haldane’s rule.
KW  - sexual development dysgenesis
KW  - Medaka fish
KW  - sex-determining genes.
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300295
VL  - 12
IS  - 1
ER  -