KLHL23 Regulates a Novel Positive-Feedback Signaling Loop of EMT Maintaining the Mesenchymal State of Cancer Cells during Metastasis
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ABSTRACT: Epithelial-mesenchymal transition (EMT) is initiated and regulated by a transcriptional reprogramming in response to microenvironmental cues. How cancer cells overcome the lack of such cues during the metastatic journey remains unclear. Here we report a novel positive-feedback loop of EMT that maintains the mesenchymal traits of cancer cells during metastasis. Using subgenome-wide screening, we identified KLHL23 as a tumor invasion suppressor, which binds to actin and suppresses actin-filament formation. Silencing or ectopic expression of KLHL23 induces EMT or MET (mesenchymal-epithelial transition), respectively, through its action on actin dynamics. Increased actin-dynamics by silencing KLHL23 or treatment with F-actin disruptors or inducers enhances the EMT transcriptional reprogramming via the induction of ROS, HIF-1a, HIF-2a and NOTCH signalling pathways in cancer cells under stress or ongoing EMT. Downregulation of KLHL23 is found in human liver and pancreatic cancers and associated with tumor metastasis and poor prognosis.
Project description:Epithelial to Mesenchymal Transition (EMT) has been associated with cancer cell heterogeneity, plasticity and metastasis. It has been the subject of several modeling effort. This logical model of the EMT cellular network aims to assess microenvironmental signals controlling cancer-associated phenotypes amid the EMT continuum. Its outcomes relate to the qualitative degrees of cell adhesions by adherent junctions and focal adhesions, two features affected during EMT. Model attractors recover epithelial, mesenchymal and hybrid phenotypes, and simulations show that hybrid phenotypes may arise through independent molecular paths, involving stringent extrinsic signals.
Of particular interest, model predictions and their experimental validations indicated that: 1) ECM stiffening is a prerequisite for cells overactivating FAK-SRC to upregulate SNAIL1 and acquire a mesenchymal phenotype, and 2) FAK-SRC inhibition of cell-cell contacts through the Receptor Protein Tyrosine Phosphates kappa leads to the acquisition of a full mesenchymal rather than a hybrid phenotype.
Project description:Metastatic disease is a primary cause of cancer-related death, and factors governing tumor cell metastasis have not been fully elucidated. Here we addressed this question by using tumor cell lines derived from mice that develop metastatic lung adenocarcinoma owing to expression of mutant K-ras and p53. A feature of metastasis-prone tumor cells that distinguished them from metastasis-incompetent tumor cells was plasticity in response to changes in their microenvironment. They transited reversibly between epithelial and mesenchymal states, forming highly polarized epithelial spheres in 3-dimensional culture that underwent epithelial-mesenchymal transition (EMT) following treatment with transforming growth factor-beta or injection into syngeneic mice. This plasticity was entirely dependent upon the microRNA-200 family, which decreased during EMT. Forced expression of miR-200 abrogated the capacity of these tumor cells to undergo EMT, invade, and metastasize and conferred transcriptional features of metastasis-incompetent tumor cells. We conclude that microenvironmental cues direct tumor metastasis by regulating miR-200 expression.
Project description:This model is an expansion of the Regan2022 - Mechanosensitive EMT model (MODEL2208050001); it includes a TGFβ signaling module and autocrine signaling in mesenchymal cells. The expanded 150-node (630 link) modular model undergoes EMT triggered by biomechanical and growth signaling crosstalk, or by TGFβ. As its predecessor, this model also reproduces the ability of the core EMT transcriptional network to maintain distinct epithelial, hybrid E/M and mesenchymal states, as well as EMT driven by mitogens such as EGF on stiff ECM. We also reproduce the observed lack of stepwise MET, in that our model's dynamics does not pass through the hybrid E/M state during MET. We show that in the absence of strong autocrine signals such as TGFβ (not included in this version), cells cannot maintain their mesenchymal state in the absence of mitogens, on softer matrices, or at high cell density. In contrast, potent autocrine signaling can stabilize the mesenchymal state in all but very dense monolayers on soft ECM. This expanded model also reproduces the inhibitory effects of TGFβ on proliferation and anoikis resistance in mesenchymal cells, as well as its ability to trigger apoptosis on soft ECM vs. EMT on stiff matrices. The model offers several experimentally testable predictions related to the effect of neighbors on partial vs. full EMT, the tug of war between mitosis and the maintenance of migratory hybrid E/M states, as well as cell cycle defects in dynamic, heterogeneous populations of epithelial, hybrid E/M and mesenchymal cells.
Project description:Hypoxia regulates epithelial to mesenchymal transition (EMT) of cancer cells. However, the mechanism underlying hypoxia-mediated EMT remains largely unknow. Here, utilizing colorectal cell carcinoma (CRC) as a model, we find that HUNK inhibits EMT and suppresses metastasis of CRC cells via its substrate GEF-H1 in a kinase-dependent manner. Mechanistically, HUNK directly phosphorylates GEF-H1 at ser645 site, which activates RhoA and consequently leads to a cascade of phosphorylation of LIMK1/CFL-1, thereby stabilizing F-actin and inhibiting EMT. Moreover, hypoxia suppresses HUNK activity and dephosphorylates GEF-H1 to promote EMT. Clinically, the expression levels of both HUNK and phosphorylation of GEH-H1 ser645 are not only downregulated in CRC tissues with metastasis compared to that without metastasis, but also positively correlated among these tissues. Our findings highlight the importance of hypoxia-regulated HUNK kinase activity and phosphorylation of GEF-H1 in regulation of EMT and metastasis of CRC.
Project description:This SuperSeries is composed of the following subset Series: GSE39356: MiR-374a Promotes Epithelial-Mesenchymal Transition (EMT) and Metastasis of Breast Cancer (mRNA dataset) GSE39358: MiR-374a Promotes Epithelial-Mesenchymal Transition (EMT) and Metastasis of Breast Cancer (miRNA dataset) Refer to individual Series
Project description:<p>The involvement of membrane-bound solute carriers (SLCs) in neoplastic transdifferentiation processes is poorly defined. Here, we examined changes in the SLC landscape during epithelial-mesenchymal transition (EMT) of pancreatic cancer cells. We show that two SLCs from the organic anion/cation transporter family, SLC22A10 and SLC22A15, favor EMT via interferon (IFN) α and γ signaling activation of receptor tyrosine kinase-like orphan receptor 1 (ROR1) expression. In addition, SLC22A10 and SLC22A15 allow tumor cell accumulation of glutathione to support EMT via the IFNα/γ-ROR1 axis. Moreover, a pan-SLC22A inhibitor lesinurad reduces EMT-induced metastasis and gemcitabine chemoresistance to prolong survival in mouse models of pancreatic cancer, thus identifying new vulnerabilities for human PDAC.</p>
Project description:Triple negative breast cancer (TNBC) is the most lethal breast cancer subgroup, as lack of targeted therapies and drug resistance reduce survival rates. Cellular plasticity enables cells to adapt non-genetically and overcome therapeutic pressure, thereby embodying a critical clinical hurdle. The epithelial-mesenchymal transition (EMT) is an example of phenotypic reprogramming linked to plasticity, drug resistance and metastasis. However, its exact impact on population diversity under therapeutic pressure is unknown. Here, we used single cell transcriptomics to investigate phenotypic diversity dynamics upon drug treatment in two human in vitro models of TNBC plasticity.
Project description:Triple negative breast cancer (TNBC) is the most lethal breast cancer subgroup, as lack of targeted therapies and drug resistance reduce survival rates. Cellular plasticity enables cells to adapt non-genetically and overcome therapeutic pressure, thereby embodying a critical clinical hurdle. The epithelial-mesenchymal transition (EMT) is an example of phenotypic reprogramming linked to plasticity, drug resistance and metastasis. However, its exact impact on population diversity under therapeutic pressure is unknown. Here, we used single cell transcriptomics to investigate phenotypic diversity dynamics upon drug treatment in two human in vitro models of TNBC plasticity.
Project description:Cancer cells undergo transcriptional reprogramming to drive tumor progression and metastasis. Here, we identified the transcriptional complex, NELF (Negative elongation factor), as an important regulator of this process. Using cancer cell lines and patient-derived tumor organoids, we demonstrated that loss of NELF inhibits breast cancer tumorigenesis and metastasis. Specifically, we found that epithelial-mesenchymal transition (EMT) and stemness-associated genes are downregulated in NELF-depleted breast cancer cells. Quantitative Multiplexed Rapid Immunoprecipitation Mass spectrometry of Endogenous proteins (qPLEX-RIME) of NELF-E, a key subunit of NELF, reveals significant rewiring of NELF-E-associated chromatin partners as a function of EMT, and further illuminates a co-option of NELF-E with the key EMT transcription factor SLUG. Accordingly, loss of NELF-E led to impaired SLUG binding on chromatin. Through integrative transcriptomic and genomic analyses, we identified the histone acetyltransferase, KAT2B, as a key functional target of NELF-E-SLUG. Genetic and pharmacological inactivation of KAT2B ameliorate expression of critical EMT marker genes, phenocopying NELF ablation. Elevated NELF-E and KAT2B expressions are associated with poorer prognosis in breast cancer patients, highlighting the clinical relevance of our findings. Importantly, KAT2B knockout mice are viable, raising the exciting prospect of targeting this dependency therapeutically. Taken together, we uncovered a crucial role of the NELF-E-KAT2B epigenetic axis in breast cancer carcinogenesis.
Project description:We studied the extent of chromatin remodeling in an in-vitro model of the epithelial-mesenchymal transition (EMT). EMT is induced in spheroid cultures (3D) using simultaneously two cytokines: TGFbeta and TNFalpha. The epithelial-mesenchymal transition (EMT) is a cellular de-differentiation process that has been implicated in cancer progression and metastasis. Increasing evidence suggests that EMT is regulated and established by epigenetic reprogramming, however a systems-level mechanism describing how chromatin remodeling contributes to the phenotypic switch is not known. We have generated genome-wide maps of 18 histone modifications/variants and variants in both the epithelial and mesenchymal states and quantified patterns of epigenetic changes at gene and enhancer loci. Clusters of these patterns reveal that EMT-related genes and their proximal enhancers are regulated through coordinated patterns of chromatin activation and repression at both gene and enhancer loci. At the cellular level, the remodeling of gene loci translates into a modular protein interaction network that recapitulates EMT-related signaling. Moreover, differentially activated or repressed enhancers are associated with two non-overlapping sets of transcription factors. We propose a chromatin-mediated regulatory feedback loop model where the NFkappaB and AP-1 transcription factors (TFs) bind activated enhancers, that regulate EMT-related genes, which in turn activate signaling pathways upstream of these TFs.