Phosphorylation of the proline-rich domain of WAVE3 drives its oncogenic activity in breast cancer.
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ABSTRACT:
SUBMITTER: Kansakar U
PROVIDER: S-EPMC7887190 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundMetastatic breast cancer is responsible for the death of the majority of breast cancer patients. In fact, metastatic BC is the 2nd leading cause of cancer-related deaths in women in the USA and worldwide. Triple negative breast cancer (TNBC), which lacks expression of hormone receptors (ER-α and PR) and ErbB2/HER2, is especially lethal due to its highly metastatic behavior, propensity to recur rapidly, and for its resistance to standard of care therapies, through mechanisms that remain incompletely understood. WAVE3 has been established as a promoter of TNBC development and metastatic progression. In this study, we investigated the molecular mechanisms whereby WAVE3 promotes therapy-resistance and cancer stemness in TNBC, through the regulation of β-catenin stabilization.MethodsThe Cancer Genome Atlas dataset was used to assess the expression of WAVE3 and β-catenin in breast cancer tumors. Kaplan-Meier Plotter analysis was used to correlate expression of WAVE3 and β-catenin with breast cancer patients' survival probability. MTT assay was used to quantify cell survival. CRISPR/Cas9-mediated gene editing, 2D and 3D tumorsphere growth and invasion assays, Immunofluorescence, Western blotting, Semi-quantitative and real-time quantitative PCR analyses were applied to study the WAVE3/β-catenin oncogenic signaling in TNBC. Tumor xenograft assays were used to study the role of WAVE3 in mediating chemotherapy resistance of TNBC tumors.ResultsGenetic inactivation of WAVE3 in combination of chemotherapy resulted in inhibition of 2D growth and 3D tumorsphere formation and invasion of TNBC cells in vitro, as well as tumor growth and metastasis in vivo. In addition, while re-expression of phospho-active WAVE3 in the WAVE3-deficient TNBC cells restored the oncogenic activity of WAVE3, re-expression of phospho-mutant WAVE3 did not. Further studies revealed that dual blocking of WAVE3 expression or phosphorylation in combination with chemotherapy treatment inhibited the activity and expression and stabilization of β-catenin. Most importantly, the combination of WAVE3-deficiency or WAVE3-phospho-deficiency and chemotherapy suppressed the oncogenic behavior of chemoresistant TNBC cells, both in vitro and in vivo.ConclusionWe identified a novel WAVE3/β-catenin oncogenic signaling axis that modulates chemoresistance of TNBC. This study suggests that a targeted therapeutic strategy against WAVE3 could be effective for the treatment of chemoresistant TNBC tumors.
| S-EPMC10035207 | biostudies-literature
Project description:The application of high-throughput genomic approaches has revealed 24 novel risk loci for Alzheimer's disease (AD). We recently reported that the bridging integrator 1 (BIN1) risk gene is linked to Tau pathology.We used glutathione S-transferase pull-down assays and nuclear magnetic resonance (NMR) experiments to demonstrate that BIN1 and Tau proteins interact directly and then map the interaction between BIN1's SH3 domain and Tau's proline-rich domain (PRD) . Our NMR data showed that Tau phosphorylation at Thr231 weakens the SH3-PRD interaction. Using primary neurons, we found that BIN1-Tau complexes partly co-localize with the actin cytoskeleton; however, these complexes were not observed with Thr231-phosphorylated Tau species.Our results show that (i) BIN1 and Tau bind through an SH3-PRD interaction and (ii) the interaction is downregulated by phosphorylation of Tau Thr231 (and potentially other residues). Our study sheds new light on regulation of the BIN1/Tau interaction and opens up new avenues for exploring its complex's role in the pathogenesis of AD.
| S-EPMC4580349 | biostudies-literature
Project description:Resistance to therapy is the main cause of tumor recurrence and metastasis and cancer stem cells (CSCs) play a crucial role in this process, especially in triple-negative breast cancers (TNBCs). Unfortunately, no FDA-approved treatment is currently available for this subtype of BC, which explains the high rate of mortality in patients with TNBC tumors. WAVE3, a member of the WASP/WAVE actin-cytoskeleton remodeling family of protein, has been established as a major driver of tumor progression and metastasis of several solid tumors, including those originating in the breast. Our recently published studies found WAVE3 to mediate the process of chemoresistance in TNBCs. The molecular mechanisms whereby WAVE3 regulates chemoresistance in TNBC tumors remains largely unknown, as does the role of WAVE3 in CSC maintenance. Here we show that WAVE3 promotes CSC self-renewal and regulates transcription of CSC-specific genes, which, in part, provides a mechanistic explanation for the function of WAVE3 in chemoresistance in TNBCs. Our data show that WAVE3 is enriched in the CSC-subpopulation of TNBC cell lines. Knockout of WAVE3 via CRISPR/Cas9 significantly attenuates the CSC-subpopulation and inhibits transcription of CSC transcription factors. Mechanistically, we established a link between WAVE3 and the Y-box-binding protein-1 (YB1), a transcription factor and CSC-maintenance gene. Indeed, the interaction of WAVE3 with YB1 is required for YB1 translocation to the nucleus of cancer cells, and activation of transcription of CSC-specific genes. Our findings identify a new WAVE3/YB1 signaling axis that regulates the CSC-mediated resistance to therapy and opens a new therapeutic window for TNBCs treatment.
| S-EPMC5732788 | biostudies-other
Project description:Both TGF-β and the PI3K-AKT signaling pathways are known activators of various intracellular pathways that regulate critical cellular functions, including cancer cell survival and proliferation. The interplay between these two oncogenic pathways plays a major role in promoting the initiation, growth, and progression of tumors, including breast cancers. The molecular underpinning of the inter-relationship between these pathways is, however, not fully understood, as is the role of WAVE3 phosphorylation in the regulation of tumor growth and progression. WAVE3 has been established as a major driver of the invasion-metastasis cascade in breast cancer and other tumors of epithelial origin. WAVE3 phosphorylation downstream of PI3K was also shown to regulate cell migration. Here we show that, in addition to PI3K, WAVE3 tyrosine phosphorylation can also be achieved downstream of TGF-β and EGF and that WAVE3 tyrosine phosphorylation is required for its oncogenic activity. Our in vitro analyses found loss of WAVE3 phosphorylation to significantly inhibit cell migration, as well as tumorsphere growth and invasion. In mouse models for breast cancer, loss of WAVE3 phosphorylation inhibited tumor growth of two aggressive breast cancer cell lines of triple-negative subtype. More importantly, we found that WAVE3 phosphorylation is also required for the activation of PI3K, TGF-β, and EGF signaling and their respective downstream effectors. Therefore, our study identified a novel function for WAVE3 in the regulation of breast cancer development and progression through the modulation of a positive feedback loop between WAVE3 and PI3K-TGF-β-EGF signaling pathways.
| S-EPMC7533250 | biostudies-literature
Project description:The mammalian adaptor protein Alix [ALG-2 (apoptosis-linked-gene-2 product)-interacting protein X] belongs to a conserved family of proteins that have in common an N-terminal Bro1 domain and a C-terminal PRD (proline-rich domain), both of which mediate partner protein interactions. Following our previous finding that Xp95, the Xenopus orthologue of Alix, undergoes a phosphorylation-dependent gel mobility shift during progesteroneinduced oocyte meiotic maturation, we explored potential regulation of Xp95/Alix by protein phosphorylation in hormone-induced cell cycle re-entry or M-phase induction. By MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS analyses and gel mobility-shift assays, Xp95 is phosphorylated at multiple sites within the N-terminal half of the PRD during Xenopus oocyte maturation, and a similar region in Alix is phosphorylated in mitotically arrested but not serum-stimulated mammalian cells. By tandem MS, Thr745 within this region, which localizes in a conserved binding site to the adaptor protein SETA [SH3 (Src homology 3) domain-containing, expressed in tumorigenic astrocytes] CIN85 (a-cyano-4-hydroxycinnamate)/SH3KBP1 (SH3-domain kinase-binding protein 1), is one of the phosphorylation sites in Xp95. Results from GST (glutathione S-transferase)-pull down and peptide binding/competition assays further demonstrate that the Thr745 phosphorylation inhibits Xp95 interaction with the second SH3 domain of SETA. However, immunoprecipitates of Xp95 from extracts of M-phase-arrested mature oocytes contained additional partner proteins as compared with immunoprecipitates from extracts of G2-arrested immature oocytes. The deubiquitinase AMSH (associated molecule with the SH3 domain of signal transducing adaptor molecule) specifically interacts with phosphorylated Xp95 in M-phase cell lysates. These findings establish that Xp95/Alix is phosphorylated within the PRD during M-phase induction, and indicate that the phosphorylation may both positively and negatively modulate their interaction with partner proteins.
| S-EPMC1820820 | biostudies-other
Project description:Proline-rich domains (PRDs) are among the most prevalent signaling modules of eukaryotes but often unexplored by biophysical techniques as their heterologous recombinant expression poses significant difficulties. Using a "divide-and-conquer" approach, we present a detailed investigation of a PRD (166 residues; ∼30% prolines) belonging to a human protein ALIX, a versatile adaptor protein involved in essential cellular processes including ESCRT-mediated membrane remodeling, cell adhesion, and apoptosis. In solution, the N-terminal fragment of ALIX-PRD is dynamically disordered. It contains three tandem sequentially similar proline-rich motifs that compete for a single binding site on its signaling partner, TSG101-UEV, as evidenced by heteronuclear NMR spectroscopy. Global fitting of relaxation dispersion data, measured as a function of TSG101-UEV concentration, allowed precise quantitation of these interactions. In contrast to the soluble N-terminal portion, the C-terminal tyrosine-rich fragment of ALIX-PRD forms amyloid fibrils and viscous gels validated using dye-binding assays with amyloid-specific probes, congo red and thioflavin T (ThT), and visualized by transmission electron microscopy. Remarkably, fibrils dissolve at low temperatures (2 to 6 °C) or upon hyperphosphorylation with Src kinase. Aggregation kinetics monitored by ThT fluorescence shows that charge repulsion dictates phosphorylation-mediated fibril dissolution and that the hydrophobic effect drives fibril formation. These data illuminate the mechanistic interplay between interactions of ALIX-PRD with TSG101-UEV and polymerization of ALIX-PRD and its central role in regulating ALIX function. This study also demonstrates the broad functional repertoires of PRDs and uncovers the impact of posttranslational modifications in the modulation of reversible amyloids.
| S-EPMC7533887 | biostudies-literature
Project description:The microtubule-associated protein Tau (MAPT) is a phosphoprotein in neurons of the brain. Aggregation of Tau is the leading cause of tauopathies such as Alzheimer's disease. Tau undergoes several post-translational modifications of which phosphorylation and O-GlcNAcylation are key chemical modifications. Tau aggregates into paired helical filaments and neurofibrillary tangles upon hyperphosphorylation, whereas O-GlcNAcylation stabilizes the soluble form of Tau. How specific phosphorylation and/or O-GlcNAcylation events influence Tau conformations remains largely unknown due to the disordered nature of Tau. In this study, we have investigated the phosphorylation- and O-GlcNAcylation-induced conformational effects on a Tau segment (Tau225-246) from the proline-rich domain (P2), by performing metadynamics simulations. We study two different phosphorylation patterns: Tau225-246, phosphorylated at T231 and S235, and Tau225-246, phosphorylated at T231, S235, S237, and S238. We also study O-GlcNAcylation at T231 and S235. We find that phosphorylation leads to the formation of strong salt-bridge contacts with adjacent lysine and arginine residues, which disrupts the native β-sheet structure observed in Tau225-246. We also observe the formation of a transient α-helix (238SAKSRLQ244) when Tau225-246 is phosphorylated at four sites. In contrast, O-GlcNAcylation shows only modest structural effects, and the resultant structure resembles the native form of the peptide. Our studies suggest the opposing structural effects of both protein post-translational modifications (PTMs) and the importance of salt bridges in governing the conformational preferences upon phosphorylation, highlighting the role of proximal arginine and lysine upon hyperphosphorylation.
| S-EPMC7459333 | biostudies-literature
Project description:DROSHA serves as a gatekeeper of the microRNA (miRNA) pathway by processing primary transcripts (pri-miRNAs). While the functions of structured domains of DROSHA have been well-documented, the contribution of N-terminal proline-rich disordered domain (PRD) remains elusive. Here we show that the PRD promotes the processing of miRNA hairpins located within introns. We identified a DROSHA isoform (p140) lacking the PRD, which is produced by proteolytic cleavage. Small RNA sequencing revealed that p140 is significantly impaired in the maturation of intronic miRNAs. Consistently, our minigene constructs demonstrated that PRD enhances the processing of intronic hairpins, but not those in exons. Splice site mutations did not affect the PRD’s enhancing effect on intronic constructs, suggesting that the PRD acts independently of splicing reaction by interacting with sequences residing within introns. The N-terminal regions from zebrafish and Xenopus DROSHA can replace the human counterpart, indicating functional conservation despite poor sequence alignment. Moreover, we found that rapidly evolving intronic miRNAs are generally more dependent on PRD than conserved ones, suggesting a role of PRD in miRNA evolution. Our study reveals a new layer of miRNA regulation mediated by a low-complexity disordered domain that senses the genomic contexts of miRNA loci.
2023-05-28 | GSE230544 | GEO
Project description:The 17q23 amplicon is associated with poor outcome in ER+ breast cancers, but the causal genes to endocrine resistance in this amplicon are unclear. Here, we interrogate transcriptome data from primary breast tumors and find that among genes in 17q23, PRR11 is a key gene associated with a poor response to therapeutic estrogen suppression. PRR11 promotes estrogen-independent proliferation and confers endocrine resistance in ER+ breast cancers. Mechanistically, the proline-rich motif-mediated interaction of PRR11 with the p85α regulatory subunit of PI3K suppresses p85 homodimerization, thus enhancing insulin-stimulated binding of p110-p85α heterodimers to IRS1 and activation of PI3K. PRR11-amplified breast cancer cells rely on PIK3CA and are highly sensitive to PI3K inhibitors, suggesting that PRR11 amplification confers PI3K dependence. Finally, genetic and pharmacological inhibition of PI3K suppresses PRR11-mediated, estrogen-independent growth. These data suggest ER+/PRR11-amplified breast cancers as a novel subgroup of tumors that may benefit from treatment with PI3K inhibitors and antiestrogens.
| S-EPMC7599336 | biostudies-literature
Project description:Huntington's disease is a heritable neurodegenerative disease that is caused by a CAG expansion in the first exon of the huntingtin gene. This expansion results in an elongated polyglutamine domain that increases the propensity of huntingtin exon-1 to form cross-β fibrils. Although the polyglutamine domain is important for fibril formation, the dynamic, C-terminal proline-rich domain (PRD) of huntingtin exon-1 makes up a large fraction of the fibril surface. Because potential fibril toxicity has to be mediated by interactions of the fibril surface with its cellular environment, we wanted to model the conformational space adopted by the PRD. We ran 800-ns long molecular dynamics simulations of the PRD using an explicit water model optimized for intrinsically disordered proteins. These simulations accurately predicted our previous solid-state NMR data and newly acquired electron paramagnetic resonance double electron-electron resonance distances, lending confidence in their accuracy. The simulations show that the PRD generally forms an imperfect polyproline (polyP) II helical conformation. The two polyP regions within the PRD stay in a polyP II helix for most of the simulation, whereas occasional kinks in the proline-rich linker region cause an overall bend in the PRD structure. The dihedral angles of the glycine at the end of the second polyP region are very variable, effectively decoupling the highly dynamic 12 C-terminal residues from the rest of the PRD.
| S-EPMC7732765 | biostudies-literature