RESUMO
BACKGROUND: Early cutaneous squamous cell carcinomas (cSCCs) generally show epithelial differentiation features and good prognosis, whereas advanced cSCCs present mesenchymal traits associated with tumor relapse, metastasis, and poor survival. Currently, the mechanisms involved in cSCC progression are unclear, and the established markers are suboptimal for accurately predicting the clinical course of the disease. METHODS: Using a mouse model of cSCC progression, expression microarray analysis, immunofluorescence and flow cytometry assays, we have identified a prognostic biomarker of tumor relapse, which has been evaluated in a cohort of cSCC patient samples. Phosphoproteomic analysis have revealed signaling pathways induced in epithelial plastic cancer cells that promote epithelial-mesenchymal plasticity (EMP) and tumor progression. These pathways have been validated by genetic and pharmacological inhibition assays. RESULTS: We show that the emergence of epithelial cancer cells expressing integrin αV (ITGAV) promotes cSCC progression to a mesenchymal state. Consistently, ITGAV expression allows the identification of patients at risk of cSCC relapse above the currently employed clinical histopathological parameters. We also demonstrate that activation of insulin-like growth factor-1 receptor (IGF1R) pathway in epithelial cancer cells is necessary to induce EMP and mesenchymal state acquisition in response to tumor microenvironment-derived factors, while promoting ITGAV expression. Likewise, ITGAV knockdown in epithelial plastic cancer cells also blocks EMP acquisition, generating epithelial tumors. CONCLUSIONS: Our results demonstrate that ITGAV is a prognostic biomarker of relapse in cSCCs that would allow improved patient stratification. ITGAV also collaborates with IGF1R to induce EMP in epithelial cancer cells and promotes cSCC progression, revealing a potential therapeutic strategy to block the generation of advanced mesenchymal cSCCs.
Assuntos
Transição Epitelial-Mesenquimal , Receptor IGF Tipo 1 , Transdução de Sinais , Neoplasias Cutâneas , Animais , Humanos , Camundongos , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/genética , Linhagem Celular Tumoral , Prognóstico , Receptor IGF Tipo 1/metabolismo , Receptor IGF Tipo 1/genética , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/genética , Microambiente Tumoral , Integrina alfaV/genética , Integrina alfaV/metabolismoRESUMO
Immune checkpoint blockade (ICB) approaches have changed the therapeutic landscape for many tumor types. However, half of cutaneous squamous cell carcinoma (cSCC) patients remain unresponsive or develop resistance. Here, we show that, during cSCC progression in male mice, cancer cells acquire epithelial/mesenchymal plasticity and change their immune checkpoint (IC) ligand profile according to their features, dictating the IC pathways involved in immune evasion. Epithelial cancer cells, through the PD-1/PD-L1 pathway, and mesenchymal cancer cells, through the CTLA-4/CD80 and TIGIT/CD155 pathways, differentially block antitumor immune responses and determine the response to ICB therapies. Accordingly, the anti-PD-L1/TIGIT combination is the most effective strategy for blocking the growth of cSCCs that contain both epithelial and mesenchymal cancer cells. The expression of E-cadherin/Vimentin/CD80/CD155 proteins in cSCC, HNSCC and melanoma patient samples predicts response to anti-PD-1/PD-L1 therapy. Collectively, our findings indicate that the selection of ICB therapies should take into account the epithelial/mesenchymal features of cancer cells.
Assuntos
Antígeno B7-H1 , Carcinoma de Células Escamosas , Plasticidade Celular , Transição Epitelial-Mesenquimal , Inibidores de Checkpoint Imunológico , Imunoterapia , Neoplasias Cutâneas , Animais , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/terapia , Neoplasias Cutâneas/tratamento farmacológico , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/terapia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/tratamento farmacológico , Camundongos , Humanos , Antígeno B7-H1/metabolismo , Antígeno B7-H1/antagonistas & inibidores , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/farmacologia , Masculino , Imunoterapia/métodos , Transição Epitelial-Mesenquimal/imunologia , Plasticidade Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Receptor de Morte Celular Programada 1/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Antígeno CTLA-4/antagonistas & inibidores , Antígeno CTLA-4/metabolismo , Antígeno CTLA-4/imunologia , Receptores Virais/metabolismo , Receptores Virais/genética , Antígeno B7-1/metabolismo , Receptores Imunológicos/metabolismoRESUMO
The human transcriptome contains thousands of small open reading frames (sORFs) that encode microproteins whose functions remain largely unexplored. Here, we show that TINCR lncRNA encodes pTINCR, an evolutionary conserved ubiquitin-like protein (UBL) expressed in many epithelia and upregulated upon differentiation and under cellular stress. By gain- and loss-of-function studies, we demonstrate that pTINCR is a key inducer of epithelial differentiation in vitro and in vivo. Interestingly, low expression of TINCR associates with worse prognosis in several epithelial cancers, and pTINCR overexpression reduces malignancy in patient-derived xenografts. At the molecular level, pTINCR binds to SUMO through its SUMO interacting motif (SIM) and to CDC42, a Rho-GTPase critical for actin cytoskeleton remodeling and epithelial differentiation. Moreover, pTINCR increases CDC42 SUMOylation and promotes its activation, triggering a pro-differentiation cascade. Our findings suggest that the microproteome is a source of new regulators of cell identity relevant for cancer.
Assuntos
Neoplasias , RNA Longo não Codificante , Sumoilação , Humanos , Neoplasias/genética , Proteínas rho de Ligação ao GTP/metabolismo , Ubiquitinas/metabolismo , RNA Longo não Codificante/genéticaRESUMO
PURPOSE: Recurrent and/or metastatic unresectable cutaneous squamous cell carcinomas (cSCCs) are treated with chemotherapy or radiotherapy, but have poor clinical responses. A limited response (up to 45% of cases) to EGFR-targeted therapies was observed in clinical trials with patients with advanced and metastatic cSCC. Here, we analyze the molecular traits underlying the response to EGFR inhibitors, and the mechanisms responsible for cSCC resistance to EGFR-targeted therapy. EXPERIMENTAL DESIGN: We generated primary cell cultures and patient cSCC-derived xenografts (cSCC-PDXs) that recapitulate the histopathologic and molecular features of patient tumors. Response to gefitinib treatment was tested and gefitinib-resistant (GefR) cSCC-PDXs were developed. RNA sequence analysis was performed in matched untreated and GefR cSCC-PDXs to determine the mechanisms driving gefitinib resistance. RESULTS: cSCCs conserving epithelial traits exhibited strong activation of EGFR signaling, which promoted tumor cell proliferation, in contrast to mesenchymal-like cSCCs. Gefitinib treatment strongly blocked epithelial-like cSCC-PDX growth in the absence of EGFR and RAS mutations, whereas tumors carrying the E545K PIK3CA-activating mutation were resistant to treatment. A subset of initially responding tumors acquired resistance after long-term treatment, which was induced by the bypass from EGFR to FGFR signaling to allow tumor cell proliferation and survival upon gefitinib treatment. Pharmacologic inhibition of FGFR signaling overcame resistance to EGFR inhibitor, even in PIK3CA-mutated tumors. CONCLUSIONS: EGFR-targeted therapy may be appropriate for treating many epithelial-like cSCCs without PIK3CA-activating mutations. Combined EGFR- and FGFR-targeted therapy may be used to treat cSCCs that show intrinsic or acquired resistance to EGFR inhibitors.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Gefitinibe/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias Epiteliais e Glandulares/tratamento farmacológico , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Neoplasias Cutâneas/tratamento farmacológico , Animais , Apoptose , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Proliferação de Células , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mutação , Neoplasias Epiteliais e Glandulares/metabolismo , Neoplasias Epiteliais e Glandulares/patologia , Inibidores de Proteínas Quinases/farmacologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In most tumors, cancer cells show the ability to dynamically transit from a non-cancer stem-like cell to a cancer stem-like cell (CSC) state and vice versa. This cell plasticity has been associated with the epithelial-to-mesenchymal transition program (EMT) and can be regulated by tumor cell-intrinsic mechanisms and complex interactions with various tumor microenvironment (TME) components. These interactions favor the generation of a specific "CSC niche" that helps maintain the main properties, phenotypic plasticity and metastatic potential of this subset of tumor cells. For this reason, TME has been recognized as an important promoter of tumor progression and therapy resistance. Tumors have evolved a network of immunosuppressive mechanisms that limits the cytotoxic T cell response to cancer cells. Some key players in this network are tumor-associated macrophages, myeloid-derived suppressor cells and regulatory T cells, which not only favor a pro-tumoral and immunosuppressive environment that supports tumor growth and immune evasion, but also negatively influences immunotherapy. Here, we review the relevance of cytokines and growth factors provided by immunosuppressive immune cells in regulating cancer-cell plasticity. We also discuss how cancer cells remodel their own niche to promote proliferation, stemness and EMT, and escape immune surveillance. A better understanding of CSC-TME crosstalk signaling will enable the development of effective targeted or immune therapies that block tumor growth and metastasis.
RESUMO
Most tumors exhibit intra-tumor heterogeneity, which is associated with disease progression and an impaired response to therapy. Cancer cell plasticity has been proposed as being an important mechanism that, along with genetic and epigenetic alterations, promotes cancer cell diversity and contributes to intra-tumor heterogeneity. Plasticity endows cancer cells with the capacity to shift dynamically between a differentiated state, with limited tumorigenic potential, and an undifferentiated or cancer stem-like cell (CSC) state, which is responsible for long-term tumor growth. In addition, it confers the ability to transit into distinct CSC states with different competence to invade, disseminate and seed metastasis. Cancer cell plasticity has been linked to the epithelial-to-mesenchymal transition program and relies not only on cell-autonomous mechanisms, but also on signals provided by the tumor microenvironment and/or induced in response to therapy. We provide an overview of the dynamic transition for cancer cell states, the mechanisms governing cell plasticity and their impact on tumor progression, metastasis and therapy response. Understanding the mechanisms involved in cancer cell plasticity will provide insights for establishing new therapeutic interventions.