Project description:Epithelial-mesenchymal plasticity contributes to a variety of biological processes, including tumour progression. A variety of epithelial-mesenchymal transition (EMT) responses have been reported and no common, EMT-defining gene expression program has been identified. Here, we have performed a comparative analysis of the EMT response, leveraging highly multiplexed single-cell RNA sequencing (scRNA-seq) to measure expression profiles of 103,999 cells from 960 samples, comprising 12 EMT time course experiments and independent kinase inhibitor screens for each.
Project description:Epithelial-mesenchymal plasticity contributes to many biological processes, including tumor progression. Various epithelial-mesenchymal transition (EMT) responses have been reported and no common, EMT-defining gene expression program has been identified. Here, we have performed a comparative analysis of the EMT response, leveraging highly multiplexed single-cell RNA sequencing (scRNA-seq) to measure expression profiles of 103,999 cells from 960 samples, comprising 12 EMT time course experiments and independent kinase inhibitor screens for each. We demonstrate that the EMT is vastly context specific, with an average of only 22% of response genes being shared between any two conditions, and over half of all response genes were restricted to 1-2 time course experiments. Further, kinase inhibitor screens revealed signaling dependencies and modularity of these responses. These findings suggest that the EMT is not simply a single, linear process, but is highly variable and modular, warranting quantitative frameworks for understanding nuances of the transition.
Project description:Depletion of Zeb1 in a KPC-model for pancreatic cancer affected strongly the formation of precursor lesions, tumour grading, invasion and notably metastasis during PDAC progression. In this context, EMT is important for metastasis, but there is variability and specificity (and not redundancy) in the role and function of different EMT-inducing transcription factors.
Project description:SNAIL is a key transcriptional regulator in embryonic development and cancer. Its effects in physiology and disease are believed to be linked to its role as a master regulator of epithelial-to-mesenchymal transition (EMT). Here, we report EMT-independent oncogenic SNAIL functions in cancer. Using genetic models, we systematically interrogated SNAIL effects in various oncogenic backgrounds and tissue types. SNAIL related phenotypes displayed remarkable tissue- and genetic context-dependencies, ranging from protective effects as observed in KRAS- or WNT-driven intestinal cancers, to dramatic acceleration of tumorigenesis, as shown in KRAS-induced pancreatic cancer. Unexpectedly, SNAIL-driven oncogenesis was not associated with E-cadherin downregulation or induction of an overt EMT program. Instead, we show that SNAIL induces bypass of senescence and cell cycle progression through p16INK4A-independent inactivation of the Retinoblastoma (RB)-restriction checkpoint. Collectively, our work identifies novel non-canonical EMT-independent functions of SNAIL and unravel its complex context-dependent role in cancer.
Project description:Epithelial-mesenchymal transition (EMT) fosters cancer cell invasion and metastasis, the main cause of cancer-related mortality. Growing evidence that SNAIL and ZEB transcription factors, typically portrayed as master regulators of EMT, may be dispensable for this process, led us to re-investigate its mechanistic underpinnings. For this, we used an unbiased computational ap-proach that integrated time-resolved analyses of chromatin structure and differential gene ex-pression, to predict transcriptional regulators of TGFβ1-inducible EMT in the MCF10A mam-mary epithelial cell line model. Bioinformatic analyses indicated comparatively minor contri-butions of SNAIL proteins and ZEB1 to TGFβ1-induced EMT, whereas the AP-1 subunit JUNB was anticipated to have a much larger impact. CRISPR/Cas9-mediated loss-of-function studies confirmed that TGFβ1-induced EMT proceeded independently of SNAIL proteins and ZEB1. In contrast, JUNB was necessary and sufficient for EMT in MCF10A cells, but not in A549 lung can-cer cells, indicating cell-type-specificity of JUNB EMT-regulatory capacity. Nonetheless, the JUNB-dependence of EMT-associated transcriptional reprogramming in MCF10A cells allowed to define a gene expression signature which was regulated by TGFβ1 in diverse cellular back-grounds, showed positively correlated expression with TGFβ signaling in multiple cancer tran-scriptomes, and was predictive of patient survival in several cancer types. Altogether, our find-ings provide novel mechanistic insights into the context-dependent control of TGFβ1-driven EMT and thereby may lead to improved diagnostic and therapeutic options.
Project description:Epithelial-mesenchymal transition (EMT) fosters cancer cell invasion and metastasis, the main cause of cancer-related mortality. Growing evidence that SNAIL and ZEB transcription factors, typically portrayed as master regulators of EMT, may be dispensable for this process, led us to re-investigate its mechanistic underpinnings. For this, we used an unbiased computational ap-proach that integrated time-resolved analyses of chromatin structure and differential gene ex-pression, to predict transcriptional regulators of TGFβ1-inducible EMT in the MCF10A mam-mary epithelial cell line model. Bioinformatic analyses indicated comparatively minor contri-butions of SNAIL proteins and ZEB1 to TGFβ1-induced EMT, whereas the AP-1 subunit JUNB was anticipated to have a much larger impact. CRISPR/Cas9-mediated loss-of-function studies confirmed that TGFβ1-induced EMT proceeded independently of SNAIL proteins and ZEB1. In contrast, JUNB was necessary and sufficient for EMT in MCF10A cells, but not in A549 lung can-cer cells, indicating cell-type-specificity of JUNB EMT-regulatory capacity. Nonetheless, the JUNB-dependence of EMT-associated transcriptional reprogramming in MCF10A cells allowed to define a gene expression signature which was regulated by TGFβ1 in diverse cellular back-grounds, showed positively correlated expression with TGFβ signaling in multiple cancer tran-scriptomes, and was predictive of patient survival in several cancer types. Altogether, our find-ings provide novel mechanistic insights into the context-dependent control of TGFβ1-driven EMT and thereby may lead to improved diagnostic and therapeutic options.
Project description:Epithelial-mesenchymal transition (EMT) fosters cancer cell invasion and metastasis, the main cause of cancer-related mortality. Growing evidence that SNAIL and ZEB transcription factors, typically portrayed as master regulators of EMT, may be dispensable for this process, led us to re-investigate its mechanistic underpinnings. For this, we used an unbiased computational ap-proach that integrated time-resolved analyses of chromatin structure and differential gene ex-pression, to predict transcriptional regulators of TGFβ1-inducible EMT in the MCF10A mam-mary epithelial cell line model. Bioinformatic analyses indicated comparatively minor contri-butions of SNAIL proteins and ZEB1 to TGFβ1-induced EMT, whereas the AP-1 subunit JUNB was anticipated to have a much larger impact. CRISPR/Cas9-mediated loss-of-function studies confirmed that TGFβ1-induced EMT proceeded independently of SNAIL proteins and ZEB1. In contrast, JUNB was necessary and sufficient for EMT in MCF10A cells, but not in A549 lung can-cer cells, indicating cell-type-specificity of JUNB EMT-regulatory capacity. Nonetheless, the JUNB-dependence of EMT-associated transcriptional reprogramming in MCF10A cells allowed to define a gene expression signature which was regulated by TGFβ1 in diverse cellular back-grounds, showed positively correlated expression with TGFβ signaling in multiple cancer tran-scriptomes, and was predictive of patient survival in several cancer types. Altogether, our find-ings provide novel mechanistic insights into the context-dependent control of TGFβ1-driven EMT and thereby may lead to improved diagnostic and therapeutic options.
Project description:This file contains a 136-node modular Boolean network model of EMT triggered by biomechanical and growth signaling crosstalk, linked to a published network of epithelial contact inhibition, proliferation, and apoptosis (MODEL2006170001). This model 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.