Project description:Chromatin and transcriptome comparisons of matched NSCs and derivative GSCs reveal activation of WNT5A and an EC signature WNT5A-mediated GdEC differentiation and EC recruitment support the invasive growth of glioma cells in the brain parenchyma.
Project description:We have previously shown that Wnt5A drives invasion in melanoma. We have also shown that Wnt5A promotes resistance to therapy designed to target the BRAF(V600E) mutation in melanoma. Here, we show that melanomas characterized by high levels of Wnt5A respond to therapeutic stress by increasing p21 and expressing classical markers of senescence, including positivity for senescence-associated ?-galactosidase (SA-?-gal), senescence-associated heterochromatic foci (SAHF), H3K9Me chromatin marks, and PML bodies. We find that despite this, these cells retain their ability to migrate and invade. Further, despite the expression of classic markers of senescence such as SA-?-gal and SAHF, these Wnt5A-high cells are able to colonize the lungs in in vivo tail vein colony-forming assays. This clearly underscores the fact that these markers do not indicate true senescence in these cells, but instead an adaptive stress response that allows the cells to evade therapy and invade. Notably, silencing Wnt5A reduces expression of these markers and decreases invasiveness. The combined data point to Wnt5A as a master regulator of an adaptive stress response in melanoma, which may contribute to therapy resistance. To better understand the molecular mechanisms governing the response of highly invasive cells to IR as compared to that of poorly invasive cells, we performed microarray analysis of both poorly and highly invasive cells at early and late timepoints after irradiation. Cells were treated with y-irradiation, and RNA was taken at 1 hour, 24 hours and 5 days after irradiation. Microarray analysis was performed using Illumina Human HT-12 ver3 expression arrays, and each time point was compared to RNA from untreated cells.
Project description:During hematopoiesis, Notch regulates both the emergence of stem and progenitor cells and the subsequent cell fate choices and differentiation. To investigate how Notch drives cells to differentiate we have used a genome-wide approach to identify direct Notch targets in Drosophila Kc cells. These data are the results from Su(H) ChIP-Chip experiments to identify genomic regions occupied by Su(H) after Notch activation in Kc cells. 3 replicates of Su(H) ChIP after 30 min. Notch activation..
Project description:Numerous pathways underlie brain invasion by tumors, a critical element underpinning recurrence and lethality in human glioblastomas (hGBMs). The identification of the master factors that elicit these pathways globally, driving invasion altogether, eludes us. We report that high expression levels of non-canonical Wnt5a characterize the most invasive gliomas, epitomize dismal prognosis and discriminate the most infiltrating mesenchymal hGBMs from proneural and classical ones. Exacerbated Wnt5a defines mesenchymal hGBM cells (Wnt5aHigh) possessing prototypical invasiveness and tumor-promoting stem-like characteristics (TPCs), but not their Wnt5aLow siblings. While inhibition of Wnt5a suppresses infiltration in mesenchymal hGBM TPCs, administration or over-expression of Wnt5a elicits the opposite effects, turning on infiltrative “mesenchymal-like” molecular programs in poorly motile, classical hGBM TPCs and Wnt5aLow mesenchymal TPCs, ex vivo and intracranially. Anti-Wnt5a antibodies or antagonist Wnt5a peptides block invasion, increasing survival in clinically relevant intracranial hGBM models. Wnt5a emerges as a master regulator in gliomatous invasion, endowing hGBM TPCs with archetypal, infiltratory transcriptional and functional profiles, providing a unique target to tackle brain invasion by hGBM cancer stem cells.
Project description:Ror2 is a member of the Ror-family of receptor tyrosine kinases acting as a receptor for Wnt5a. Wnt5a/Ror2 signaling activates primarily the ß-catenin-independent pathway, which involves various signal mediators, such as Dishevelled, c-Jun N-terminal kinase (JNK), filamin A, c-Src, and Ca2+. Wnt5a/Ror2 signaling has also been shown to inhibit the ß-catenin-dependent pathway. Wnt5a and Ror2 are overexpressed in various types of tumor cells, including osteosarcoma and melanoma cells, resulting in constitutive activation of Wnt5a/Ror2 signaling in a cell-autonomous manner. Constitutively activated Wnt5a/Ror2 signaling has been shown to play important roles in promoting invadopodia formation and invasiveness of tumor cells. However, little is known about the mechanisms underlying these processes. As an attempt to understand the mechanism by which Wnt5a/Ror2 signaling, activated constitutively in osteosarcoma cells, contributes to their highly invasive properties, we performed DNA microarray analysis using a human osteosarcoma cell line, SaOS2.
Project description:About half of all melanomas harbor a constitutively active mutant BRAFV600E/K kinase that can be selectively inhibited by targeted BRAF inhibitors (BRAFi). While patients treated with BRAFi initially exhibit measurable clinical improvement, the majority of patients eventually develop drug resistance and relapse. We observe significant elevation of WNT5A in a subset of tumors from patients exhibiting disease progression on BRAFi therapy. WNT5A transcript and protein are also elevated in BRAFi-resistant melanoma cell lines generated by long-term in vitro treatment with BRAFi. RNAi-mediated reduction in levels of endogenous WNT5A in melanoma decreases cell growth, increases apoptosis in response to BRAFi challenge, and decreases the activity of pro-survival AKT signaling. Overexpression of WNT5A conversely promotes melanoma growth and tumorigenesis and activates AKT signaling. Similar to WNT5A knockdown, knockdown of the WNT receptors FZD7 and RYK inhibits growth, sensitizes melanoma cells to BRAFi, and reduces AKT activation. Together, these findings suggest that chronic BRAF inhibition elevates WNT5A expression, which then acts through FZD7 and RYK to promote AKT signaling, leading to increased growth and therapeutic resistance. Increased WNT5A expression in BRAFi-resistant melanomas also correlates with an associated transcriptional signature, which identifies potential therapeutic targets to reduce clinical resistance to BRAFi. Expression of WNT5A-correlated genes was compared in melanoma cell lines generated to be resistant to PLX4032 and the their associated naïve parental line Basal expression of the WNT5A-correlated genes was also measured in experiments comparing each naïve line to a mixed reference pool containing equal amounts of 47 melanoma cell lines.