| 1. |
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| 2. |
- Heldin, Paraskevi, et al.
(författare)
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Involvement of hyaluronan and CD44 in cancer and viral infections
- 2020
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Ingår i: Cellular Signalling. - : ELSEVIER SCIENCE INC. - 0898-6568 .- 1873-3913. ; 65
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Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan and its major receptor CD44 are ubiquitously distributed. They have important structural as well as signaling roles, regulating tissue homeostasis, and their expression levels are tightly regulated. In addition to signaling initiated by the interaction of the intracellular domain of CD44 with cytoplasmic signaling molecules, CD44 has important roles as a co-receptor for different types of receptors of growth factors and cytokines. Dysregulation of hyaluronan-CD44 interactions is seen in diseases, such as inflammation and cancer. In the present communication, we discuss the mechanism of hyaluronan-induced signaling via CD44, as well as the involvement of hyaluronan-engaged CD44 in malignancies and in viral infections.
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| 3. |
- Jacobson, Annica, et al.
(författare)
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Hyaluronan content in experimental carcinoma is not correlated to interstitial fluid pressure.
- 2003
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Ingår i: Biochem. Biophys. Res. Commun.. ; 305, s. 1017-1023
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Tidskriftsartikel (refereegranskat)abstract
- Mechanism(s) for generation of the high tumor interstitial fluid pressure (TIFP) that is characteristic of carcinoma is not known. We investigated the role of hyaluronan, the major water-binding polysaccharide of the extracellular matrix, for the generation of a high TIFP. A human anaplastic thyroid carcinoma (KAT-4) xenografted to athymic mice and a syngeneic rat colon carcinoma (PROb) were used. Neither KAT-4 nor PROb cells produced hyaluronan (HA) in culture, however, both cell lines produced factors that stimulated HA-synthesis by cultured fibroblasts. Modulating hyaluronan levels by transfection of PROb carcinoma cells with hyaluronan synthase-2 revealed no correlation between hyaluronan content and TIFP. Furthermore, lowering of TIFP by treating KAT-4 tumors with a specific inhibitor of TGF-beta 1 and -beta 3 did not change the concentration of hyaluronan in the tumors. In summary, our results suggest that a modulation of hyaluronan content is not a major pathogenetic mechanism for the generation of the characteristically high TIFP in malignant carcinomas.
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| 4. |
- Karalis, Theodoros, et al.
(författare)
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Identification of a Small Molecule Inhibitor of Hyaluronan Synthesis, DDIT, Targeting Breast Cancer Cells
- 2022
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 14:23
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The most aggressive subtype of breast cancer, triple-negative breast cancer, is characterized by an excessive accumulation of hyaluronan in the cancer and its peritumoral stroma, which has been linked to poor prognosis of the patients. Inhibitors of hyaluronan synthesis would thus have a potential clinical value. We have identified the thymidine analog 5 '-Deoxy-5 '-(1,3-Diphenyl-2-Imidazolidinyl)-Thymidine (DDIT) as a new non-toxic inhibitor of hyaluronan synthesis. DDIT is more potent than the available inhibitor 4-Methylumbelliferone (4-MU), and significantly suppressed the aggressiveness of triple-negative breast cancer cells grown in tissue culture. Breast cancer is a common cancer in women. Breast cancer cells synthesize large amounts of hyaluronan to assist their proliferation, survival, migration and invasion. Accumulation of hyaluronan and overexpression of its receptor CD44 and hyaluronidase TMEM2 in breast tumors correlate with tumor progression and reduced overall survival of patients. Currently, the only known small molecule inhibitor of hyaluronan synthesis is 4-methyl-umbelliferone (4-MU). Due to the importance of hyaluronan for breast cancer progression, our aim was to identify new, potent and chemically distinct inhibitors of its synthesis. Here, we report a new small molecule inhibitor of hyaluronan synthesis, the thymidine analog 5 '-Deoxy-5 '-(1,3-Diphenyl-2-Imidazolidinyl)-Thymidine (DDIT). This compound is more potent than 4-MU and displays significant anti-tumorigenic properties. Specifically, DDIT inhibits breast cancer cell proliferation, migration, invasion and cancer stem cell self-renewal by suppressing HAS-synthesized hyaluronan. DDIT appears as a promising lead compound for the development of inhibitors of hyaluronan synthesis with potential usefulness in breast cancer treatment.
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| 5. |
- Karousou, Eugenia, et al.
(författare)
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The activity of hyaluronan synthase 2 is regulated by dimerization and ubiquitination
- 2010
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Ingår i: Journal of Biological Chemistry. - USA : The American Society for Biochemistry and Molecular Biology, Inc.. - 0021-9258 .- 1083-351X. ; 285:31, s. 23647-23654
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Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan is a component of the extracellular matrix, which affects tissue homeostasis. In this study, we investigated the regulatory mechanisms of one of the hyaluronan-synthesizing enzymes, HAS2. Ectopic expression of Flag- and 6myc-HAS2 in COS-1 cells followed by immunoprecipitation and immunoblotting revealed homodimers; after co-transfection with Flag-HAS3, also heterodimers were seen. Furthermore, the expressed HAS2 was ubiquitinated. We identified one acceptor site for ubiquitin on lysine residue 190. Mutation of this residue led to inactivation of the enzymatic activity of HAS2. Interestingly, K190R-mutated HAS2 formed dimers with wt HAS2 and quenched the activity of wt HAS2, thus demonstrating a functional role of the dimeric configuration.
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| 6. |
- Kolliopoulos, Constantinos, et al.
(författare)
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CD44 Depletion in Glioblastoma Cells Suppresses Growth and Stemness and Induces Senescence
- 2022
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:15
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The hyaluronan receptor CD44 has an important role in glioblastoma multiforme (GBM) progression, but the precise mechanisms have not been elucidated. We have analyzed U251MG glioma cells, expressing CD44 or not, and grown in stem cell-like enriched spheres. Our results revealed that CD44 is important for cell growth and stemness, and for the prevention of senescence. Analysis by RNA sequencing revealed that CD44 is important for the interaction with the hyaluronan-enriched microenvironment. In addition, CD44 depletion impairs certain gene signatures, such as those for platelet-derived growth factor (PDGF) isoforms and PDGF receptors, as well as signatures related to hypoxia, glycolysis, and anti-tumor immune responses. Glioblastoma multiforme (GBM) is a lethal brain tumor, characterized by enhanced proliferation and invasion, as well as increased vascularization and chemoresistance. The expression of the hyaluronan receptor CD44 has been shown to correlate with GBM progression and poor prognosis. Here, we sought to elucidate the molecular mechanisms by which CD44 promotes GBM progression by knocking out (KO) CD44, employing CRISPR/Cas9 gene editing in U251MG cells. CD44-depleted cells exhibited an impaired proliferation rate, as shown by the decreased cell numbers, decreased Ki67-positive cell nuclei, diminished phosphorylation of CREB, and increased levels of the cell cycle inhibitor p16 compared to control cells. Furthermore, the CD44 KO cells showed decreased stemness and increased senescence, which was manifested upon serum deprivation. In stem cell-like enriched spheres, RNA-sequencing analysis of U251MG cells revealed a CD44 dependence for gene signatures related to hypoxia, the glycolytic pathway, and G2 to M phase transition. Partially similar results were obtained when cells were treated with the gamma-secretase inhibitor DAPT, which inhibits CD44 cleavage and therefore inhibits the release of the intracellular domain (ICD) of CD44, suggesting that certain transcriptional responses are dependent on CD44-ICD. Interestingly, the expression of molecules involved in hyaluronan synthesis, degradation, and interacting matrix proteins, as well as of platelet-derived growth factor (PDGF) isoforms and PDGF receptors, were also deregulated in CD44 KO cells. These results were confirmed by the knockdown of CD44 in another GBM cell line, U2990. Notably, downregulation of hyaluronan synthase 2 (HAS2) impaired the hypoxia-related genes and decreased the CD44 protein levels, suggesting a CD44/hyaluronan feedback circuit contributing to GBM progression.
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| 7. |
- Kolliopoulos, Constantinos, et al.
(författare)
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Has2 natural antisense RNA and Hmga2 promote Has2 expression during TGFβ-induced EMT in breast cancer
- 2019
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Ingår i: Matrix Biology. - : Elsevier BV. - 0945-053X .- 1569-1802. ; 80, s. 29-45
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Tidskriftsartikel (refereegranskat)abstract
- The glycosaminoglycan hyaluronan has a crucial role in tissue organization and cell signaling. Hyaluronan accumulates in conjunction with rapid tissue remodeling during embryogenesis, as well as in inflammatory conditions and cancer. We report a negative correlation between the expression of genes encoding hyaluronan synthase HAS2, its natural antisense transcript HAS2-AS, the chromatin modulating factor HMGA2 and transforming growth factor-β (TGFβ), and survival of patients with invasive breast carcinomas. In mouse mammary epithelial cells, TGFβ activates Smad and non-Smad signaling pathways, resulting in the transcriptional induction of Has2, Has2as (the mouse ortholog of HAS2-AS) and Hmga2, as well as epithelial-mesenchymal transition (EMT)-promoting transcription factors, such as Snail. Importantly, Has2as abrogation suppressed the TGFβ induction of EMT markers, including Snai1, Hmga2, Fn1, and suppressed the mesenchymal phenotype. TGFβ induction of Hmga2, Has2as and Has2, and synthesis of hyaluronan were accompanied with activation of Akt and Erk1/2 MAP-kinase signaling and were required for breast cancer cell motility. Importantly, the hyaluronan receptor Cd44, but not Hmmr, was required for TGFβ-mediated EMT phenotype. Interestingly, Has2as was found to contribute to the maintenance of stem cell factors and breast cancer stemness. Our findings show that Has2as has a key role in TGFβ- and HAS2-induced breast cancer EMT, migration and acquisition of stemness.
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| 8. |
- Kolliopoulos, Constantinos, et al.
(författare)
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TRAF4/6 Is Needed for CD44 Cleavage and Migration via RAC1 Activation
- 2021
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary Tumor cells receive signals from the surrounding extracellular matrix that affect their growth and survival. An important component of the extracellular matrix is the large polysaccharide hyaluronan, which binds and activates certain receptors at the cell surface, including CD44. Activation of CD44 initiates several signaling pathways; one of them involves the cleavage of CD44 by proteases, leading to the release of the intracellular domain of CD44, which after translocation to the nucleus affects the transcription of certain genes. In the present report, we elucidate the mechanism by which CD44 is cleaved, and show that this occurs at an increased rate in stem-like tumor cells grown in spheres. We also show that CD44 cleavage promotes the migration of tumor cells. Since the mechanism we have elucidated promotes tumorigenesis, it is possible that inhibition of this pathway may be beneficial in the treatment of tumor patients. The hyaluronan receptor CD44 can undergo proteolytic cleavage in two steps, leading to the release of its intracellular domain; this domain is translocated to the nucleus, where it affects the transcription of target genes. We report that CD44 cleavage in A549 lung cancer cells and other cells is promoted by transforming growth factor-beta (TGF beta) in a manner that is dependent on ubiquitin ligase tumor necrosis factor receptor-associated factor 4 or 6 (TRAF4 or TRAF6, respectively). Stem-like A549 cells grown in spheres displayed increased TRAF4-dependent expression of CD44 variant isoforms, CD44 cleavage, and hyaluronan synthesis. Mechanistically, TRAF4 activated the small GTPase RAC1. CD44-dependent migration of A549 cells was inhibited by siRNA-mediated knockdown of TRAF4, which was rescued by the transfection of a constitutively active RAC1 mutant. Our findings support the notion that TRAF4/6 mediates pro-tumorigenic effects of CD44, and suggests that inhibitors of CD44 signaling via TRAF4/6 and RAC1 may be beneficial in the treatment of tumor patients.
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| 9. |
- Kolliopoulos, Constantinos, et al.
(författare)
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Transforming growth factor β (TGFβ) induces NUAK kinase expression to fine-tune its signaling output
- 2019
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 294:11, s. 4119-4136
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Tidskriftsartikel (refereegranskat)abstract
- TGFβ signaling via SMAD proteins and protein kinase pathways up- or down-regulates the expression of many genes and thus affects physiological processes, such as differentiation, migration, cell cycle arrest, and apoptosis during developmental or adult tissue homeostasis. We here report that NUAK family kinase 1 (NUAK1) and NUAK2 are two TGFβ target genes. NUAK1/2 belong to the AMP-activated protein kinase (AMPK) family, whose members control central and protein metabolism, polarity and overall cellular homeostasis. We found that TGFβ-mediated transcriptional induction of NUAK1 and NUAK2 requires SMAD family members 2, 3 and 4 (SMAD2/3/4) and mitogen activated protein kinase (MAPK) activities, which provided immediate and early signals for the transient expression of these two kinases. Genomic mapping identified an enhancer element within the first intron of the NUAK2 gene that can recruit SMAD proteins, which, when cloned, could confer induction by TGFβ. Furthermore, NUAK2 formed protein complexes with SMAD3 and the TGFβ type I receptor. Functionally, NUAK1 suppressed and NUAK2 induced TGFβ signaling. This was evident during TGFβ-induced epithelial cytostasis, mesenchymal differentiation and myofibroblast contractility, in which NUAK1 or NUAK2 silencing enhanced or inhibited these responses, respectively. In conclusion, we have identified a bifurcating loop during TGFβ signaling, whereby transcriptional induction of NUAK1 serves as a negative checkpoint and NUAK2 induction positively contributes to signaling and terminal differentiation responses to TGFβ activity.
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| 10. |
- Kolliopoulos, Konstantinos, 1986-, et al.
(författare)
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Effect of CD44 on glioma cell progression, invasion and senescence
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Glioblastoma multiforme (GBM) is a lethal brain tumor, characterized by enhanced proliferation rate, increased invasive capacity, and chemoresistance. The expression of the hyaluronan receptor CD44 correlates with GBM progression and poor prognosis. We have initiated studies to elucidate the molecular mechanisms behind the effects of CD44 on tumorigenesis by knocking out (KO) CD44, via employing CRISPR/Cas9 gene editing in U251MG cells. CD44-depleted cells exhibited impaired proliferation rate, as confirmed by decreased cell numbers, Ki67 positive nuclei, diminished p-CREB levels, and increased levels of the cell cycle inhibitor p16 compared to control cells. Furthermore, the CD44 KO cells acquired a pro-senescence state, which was manifested upon serum deprivation. Interestingly, CD44 KO cells showed enhanced migratory and invasive properties, as observed in 2D wound healing and 3D collagen assays, which may be partially attributed to the acquisition of a senescence-associated secretory phenotype (SASP) and activation of the ERK1/2 MAPK pathway. RNA-sequencing analysis of stem-like U251MG cells, grown in spheres, unveiled a CD44-dependency for expression of molecules involved in hyaluronan synthesis and degradation, and of members of the PDGF and PDGF receptor families. These observations highlight the importance of CD44 on GBM progression.
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