Transcriptomics analysis of oligodendrocyte-enriched sorted cells with conditional deletion of Ral GTPases during development
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE180725 | GEO | 2022/09/27
REPOSITORIES: GEO
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Project description:Abstract: RAS-like (RAL) GTPases function in Wnt signalling-dependent intestinal stem cell proliferation and regeneration. Whether RAL proteins work as canonical RAS effectors in the intestine, and the mechanisms of how they contribute to tumorigenesis remain unclear. Here, we show that RAL GTPases are necessary and sufficient to activate EGFR/MAPK signalling in the intestine. We identify non-canonical roles of RAL GTPases not as RAS effectors, but rather by acting upstream of RAS activation via induction of EGFR internalisation . Knocking down Drosophila RalA from intestinal stem and progenitor cells leads to increased levels of plasma membrane-associated EGFR and decreased MAPK pathway activation. Importantly, in addition to impacting stem cell proliferation and damage-induced intestinal regeneration, this function of RAL GTPases drives EGFR-dependent tumorigenic growth in the intestine and in human mammary epithelium. Altogether, our results reveal previously unrecognised cellular and molecular contexts where RAL GTPases become essential mediators of EGFR-driven tissue homeostasis and malignant transformation. Results: RalA is required within ISCs to induce midgut adult midgut regeneration following damage by oral infection with Erwinia carotovora carotovora 15 (Ecc15) (Johansson et al., 2019). To achieve a global view of intestinal pathways affected by RalA, we performed a transcriptomic analysis by RNAseq of whole midguts from vehicle treated (Mock) or damaged (Ecc15 fed) control animals or following RalA knockdown in intestinal stem and progenitor cells using the escargot-gal4 driver (ISC/EB>) (Micchelli and Perrimon, 2006). Consistent with its effect on ISC proliferation (Johansson et al., 2019), RalA knockdown significantly impaired damage-induced upregulation of cell cycle genes in the midgut. Additionally, levels of multiple transcriptional targets of the EGFR/MAPK pathway (Golembo et al., 1996; Hsu et al., 2001; Jin et al., 2015; Meng and Biteau, 2015), such as argos (aos), rhomboid (rho), Sox21a and string (stg) were increased following Ecc15 infection in control midguts. The upregulation of these target genes was significantly impaired upon RalA knockdown.
2021-02-01 | GSE162421 | GEO
Project description:RAL GTPases mediate EGFR/MAPK signalling-driven intestinal stem cell proliferation and tumourigenesis upstream of RAS activation.
| PRJNA681831 | ENA
Project description:Cancer extracellular vesicles (EVs) mainly exert pro-tumoral functions by changing the phenotypes of stromal cells to the benefit of tumor growth and metastasis. In particular, they shuttle to distant organs and seed pre-metastatic niches facilitating subsequent colonization by circulating tumor cells. The levels of tumor secreted EVs have been correlated to tumor aggressiveness, however, the link between EV secretion mechanisms, their capacity to form pre-metastatic niches and the actual formation of metastasis remains obscure. Here, we show that two GTPases RalA and RalB control, through the phospholipase PLD1, the homeostasis of multi-vesicular bodies and thereby tune the biogenesis and secretion of a subtype of (pro-metastatic) EVs. Mice experiments revealed that RalA and RalB promote lung metastasis of mammary carcinoma cells without affecting their invasive behaviors. Importantly, we show in vivo that EVs from RalA or RalB depleted cells have limited organotropic capacities and, as a consequence, are less efficient in priming lung metastasis. Furthermore, we show that such EVs lack the adhesion molecule MCAM/CD146, which is responsible for EVs organotropism. Finally, we show that RalA and RalB have increased expression in human breast cancer patients with lung metastasis. Altogether, our study identifies Ral GTPases as central molecules linking the mechanisms of EVs secretion, cargo loading to their capacity to disseminate and induce pre-metastatic niches.
2021-09-09 | PXD020180 | Pride
Project description:Pancreatic ductal adenocarcinoma, caused by activating mutation in K-Ras, is an aggressive malignancy due to its early invasion and matastasis. Ral GTPases, negatively regulated by RalGAP, are activated downstream of Ras and play a crucial role in development and progression of pancreatic ductal adenocarcinoma. However, the underlying mechanisms remain unclear. We used microarrays to detail the global programme of gene expression underlying the human pancreatic ductal adenocarcinoma cell line, MIA PaCa-2 with RalGAPβ deficiency or not, and identified distinct classes of Ral activation-related mRNA.
2023-04-24 | GSE223382 | GEO
Project description:Activated HER2 and EGFR stimulate the Ras small GTPases, which in turn primarily activate the MAPK, PI3K-Akt and RalGEF-Ral pathways. While activation of the MAPK and PI3K-Akt pathways downstream of HER2 and EGFR promote mammary tumorigenesis, little is known regarding the role of the RalGEF-Ral pathway. RalGEFs convert the small GTPases RalA and RalB to an active GTP-bound state. Of the two proteins, only activated RalA is transforming, while RalB is more important for cell motility, and hence we investigated the role of RalA in HER2-overexpressing and EGFR-positive breast cancer. We now report that shRNA-mediated knockdown of RalA reduced the in vitro transformed growth and in vivo tumorigenic growth of MDA-MB-231 human breast cancer cells, while knockdown of RalB reduced migration and invasion. Lastly, we demonstrate that expression of activated HER2 increases RalA-GTP levels, and that a number of genes associated with activated RalA are elevated in tumor compared to normal mammary tissue. Taken together, these results suggest a possible role for RalA in mammary tumorigenesis. Four independent cultures of HEK-HT cells stably infected with a retrovirus confirmed to expressed RalAQ72L and four independent cultures of HEK-HT cells stably infected with a control retrovirus RalA activation expression analysis
2016-02-13 | E-GEOD-19295 | biostudies-arrayexpress
Project description:We performed CBX3 knockdown in lung adenocarcinoma cells along with RNA sequencing. The expression profiling showed Rho GTPases signaling as a potential CBX3 target and the conclusions were also verified in clinical samples.
2021-05-05 | GSE173858 | GEO
Project description:Activated HER2 and EGFR stimulate the Ras small GTPases, which in turn primarily activate the MAPK, PI3K-Akt and RalGEF-Ral pathways. While activation of the MAPK and PI3K-Akt pathways downstream of HER2 and EGFR promote mammary tumorigenesis, little is known regarding the role of the RalGEF-Ral pathway. RalGEFs convert the small GTPases RalA and RalB to an active GTP-bound state. Of the two proteins, only activated RalA is transforming, while RalB is more important for cell motility, and hence we investigated the role of RalA in HER2-overexpressing and EGFR-positive breast cancer. We now report that shRNA-mediated knockdown of RalA reduced the in vitro transformed growth and in vivo tumorigenic growth of MDA-MB-231 human breast cancer cells, while knockdown of RalB reduced migration and invasion. Lastly, we demonstrate that expression of activated HER2 increases RalA-GTP levels, and that a number of genes associated with activated RalA are elevated in tumor compared to normal mammary tissue. Taken together, these results suggest a possible role for RalA in mammary tumorigenesis.
2016-02-13 | GSE19295 | GEO
Project description:We used RNA sequencing to examine the transcriptional changes in differentiated oligodendrocytes, oligodendrocyte precursor cells, astroctytes, and microglia after blocking exocytosis from oligodendrocyte-lineage cells
2022-10-31 | GSE168569 | GEO
Project description:We have used microarray technology to identify the transcriptional targets of Rho subfamily GTPases. This analysis indicated that murine fibroblasts transformed by these proteins show similar transcriptomal profiles. Functional annotation of the regulated genes indicate that Rho subfamily GTPases target a wide spectrum of biological functions, although loci encoding proteins linked to proliferation and DNA synthesis/transcription are up-regulated preferentially. Rho proteins promote four main networks of interacting proteins nucleated around E2F, c-Jun, c-Myc, and p53. Of those, E2F, c-Jun and c-Myc are essential for the maintenance of cell transformation. Inhibition of Rock, one of the main Rho GTPase targets, leads to small changes in the transcriptome of Rho-transformed cells. Rock inhibition decreases c-myc gene expression without affecting the E2F and c-Jun pathways. Loss-of-function studies demonstrate that c-Myc is important for the blockage of cell-contact inhibition rather than for promoting the proliferation of Rho-transformed cells. However, c-Myc overexpression does not bypass the inhibition of cell transformation induced by Rock blockage, indicating that c-Myc is essential, but not sufficient, for Rock-dependent transformation. These results reveal the complexity of the genetic program orchestrated by the Rho subfamily and pinpoint protein networks that mediate different aspects of the malignant phenotype of Rho-transformed cells Keywords: Rho/Rac GTPases, microarray, oncogenesis, proliferation, gene expression, transcription, Rock, c-Myc
2007-01-03 | GSE5913 | GEO
Project description: Not available
| S-EPMC5083013 | biostudies-literature