RESUMO
Epithelial-mesenchymal transition (EMT) empowers epithelial cells with mesenchymal and stem-like attributes, facilitating metastasis, a leading cause of cancer-related mortality. Hybrid epithelial-mesenchymal (E/M) cells, retaining both epithelial and mesenchymal traits, exhibit heightened metastatic potential and stemness. The mesenchymal intermediate filament, vimentin, is upregulated during EMT, enhancing the resilience and invasiveness of carcinoma cells. The phosphorylation of vimentin is critical to its structure and function. Here, we identify that stabilizing vimentin phosphorylation at serine 56 induces multinucleation, specifically in hybrid E/M cells with stemness properties but not epithelial or mesenchymal cells. Cancer stem-like cells are especially susceptible to vimentin-induced multinucleation relative to differentiated cells, leading to a reduction in self-renewal and stemness. As a result, vimentin-induced multinucleation leads to sustained inhibition of stemness properties, tumor initiation, and metastasis. These observations indicate that a single, targetable phosphorylation event in vimentin is critical for stemness and metastasis in carcinomas with hybrid E/M properties.
Assuntos
Carcinoma , Filamentos Intermediários , Humanos , Vimentina/metabolismo , Fosforilação , Filamentos Intermediários/metabolismo , Filamentos Intermediários/patologia , Carcinoma/patologia , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal , Células-Tronco Neoplásicas/metabolismo , Linhagem Celular Tumoral , Metástase Neoplásica/patologiaRESUMO
BACKGROUND: The mechanism by which immune cells regulate metastasis is unclear. Understanding the role of immune cells in metastasis will guide the development of treatments improving patient survival. METHODS: We used syngeneic orthotopic mouse tumour models (wild-type, NOD/scid and Nude), employed knockout (CD8 and CD4) models and administered CXCL4. Tumours and lungs were analysed for cancer cells by bioluminescence, and circulating tumour cells were isolated from blood. Immunohistochemistry on the mouse tumours was performed to confirm cell type, and on a tissue microarray with 180 TNBCs for human relevance. TCGA data from over 10,000 patients were analysed as well. RESULTS: We reveal that intratumoral immune infiltration differs between metastatic and non-metastatic tumours. The non-metastatic tumours harbour high levels of CD8+ T cells and low levels of platelets, which is reverse in metastatic tumours. During tumour progression, platelets and CXCL4 induce differentiation of monocytes into myeloid-derived suppressor cells (MDSCs), which inhibit CD8+ T-cell function. TCGA pan-cancer data confirmed that CD8lowPlatelethigh patients have a significantly lower survival probability compared to CD8highPlateletlow. CONCLUSIONS: CD8+ T cells inhibit metastasis. When the balance between CD8+ T cells and platelets is disrupted, platelets produce CXCL4, which induces MDSCs thereby inhibiting the CD8+ T-cell function.
Assuntos
Neoplasias da Mama/imunologia , Antígenos CD4/genética , Antígenos CD8/genética , Linfócitos T CD8-Positivos/transplante , Neoplasias Pulmonares/prevenção & controle , Neoplasias Pulmonares/secundário , Fator Plaquetário 4/metabolismo , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Feminino , Técnicas de Inativação de Genes , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos Nus , Células Supressoras Mieloides/imunologia , Células Neoplásicas Circulantes/imunologia , Fator Plaquetário 4/administração & dosagem , Fator Plaquetário 4/farmacologia , Análise de Sobrevida , Transplante Isogênico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Neural progenitor (NP) cells are the multipotent cells that produce neurons and glia in the central nervous system. Compounds regulating their proliferation are key to both understanding brain development and unlocking their potential in regenerative repair. We discuss a chemical screen that unexpectedly identified inhibitors of Erk signaling potently promoting the self-renewing divisions of fetal NP cells. This occurred through crosstalk between Erk and Akt signaling cascades. The crosstalk mechanism is cell type-specific, and is not detected in adult NP cells as well as brain tumor cells. The mechanism was also shown to be independent from the GSK-3 signaling pathway, which has been reported to be a major regulator of NP cell homeostasis and inhibitors to which were also identified in the screen. In vitro Erk inhibition led to the prolonged rapid expansion of fetal NP cells while retaining their multipotency. In vivo inhibitor administration significantly inhibited the neuronal differentiation, and resulted in increased proliferative progenitor cells in the ventricular/subventricular zone (VZ/SVZ) of the embryonic cortex. Our results uncovered a novel regulating pathway for NP cell proliferation in the developing brain. The discovery provides a pharmacological basis for in vitro expansion and in vivo manipulation of NP cells.
Assuntos
Células-Tronco Embrionárias/citologia , Sistema de Sinalização das MAP Quinases , Células-Tronco Neurais/citologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Comunicação Celular , Diferenciação Celular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Embrionárias/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Inibidores de Proteínas Quinases/farmacologia , RatosRESUMO
Small molecule compounds promoting the neuronal differentiation of stem/progenitor cells are of pivotal importance to regenerative medicine. We carried out a high-content screen to systematically characterize known bioactive compounds, on their effects on the neuronal differentiation and the midbrain dopamine (mDA) neuron specification of neural progenitor cells (NPCs) derived from the ventral mesencephalon of human fetal brain. Among the promoting compounds three major pharmacological classes were identified including the statins, TGF-ßRI inhibitors, and GSK-3 inhibitors. The function of each class was also shown to be distinct, either to promote both the neuronal differentiation and mDA neuron specification, or selectively the latter, or promote the former but suppress the latter. We then carried out initial investigation on the possible mechanisms underlying, and demonstrated their applications on NPCs derived from human pluripotent stem cells (PSCs). Our study revealed the potential of several small molecule compounds for use in the directed differentiation of human NPCs. The screening result also provided insight into the signaling network regulating the differentiation of human NPCs.