ABSTRACT
Background: Infiltration is a life-threatening growth pattern in malignant astrocytomas and a significant cause of therapy resistance. It results in the tumor cell spreading deeply into the surrounding brain tissue, fostering tumor recurrence and making complete surgical resection impossible. We need to thoroughly understand the mechanisms underlying diffuse infiltration to develop effective therapies. Methods: We integrated in vitro and in vivo functional assays, RNA sequencing, clinical, and expression information from public data sets to investigate the role of ADAM23 expression coupling astrocytoma's growth and motility. Results: ADAM23 downregulation resulted in increased infiltration, reduced tumor growth, and improved overall survival in astrocytomas. Additionally, we show that ADAM23 deficiency induces γ-secretase (GS) complex activity, contributing to the production and deposition of the Amyloid-ß and release of NICD. Finally, GS ablation in ADAM23-low astrocytomas induced a significant inhibitory effect on the invasive programs. Conclusions: Our findings reveal a role for ADAM23 in regulating the balance between cell proliferation and invasiveness in astrocytoma cells, proposing GS inhibition as a therapeutic option in ADAM23 low-expressing astrocytomas.
ABSTRACT
There are no effective strategies for the successful treatment of glioblastomas (GBM). Current therapeutic modalities effectively target bulk tumor cells but leave behind marginal GBM cells that escape from the surgical margins and radiotherapy field, exhibiting high migratory phenotype and resistance to all available anti-glioma therapies. Drug resistance is mostly driven by tumor cell plasticity: a concept associated with reactivating transcriptional programs in response to adverse and dynamic conditions from the tumor microenvironment. Autophagy, or "self-eating", pathway is an emerging target for cancer therapy and has been regarded as one of the key drivers of cell plasticity in response to energy demanding stress conditions. Many studies shed light on the importance of autophagy as an adaptive mechanism, protecting GBM cells from unfavorable conditions, while others recognize that autophagy can kill those cells by triggering a non-apoptotic cell death program, called 'autophagy cell death' (ACD). In this review, we carefully analyzed literature data and conclude that there is no clear evidence indicating the presence of ACD under pathophysiological settings in GBM disease. It seems to be exclusively induced by excessive (supra-physiological) stress signals, mostly from in vitro cell culture studies. Instead, pre-clinical and clinical data indicate that autophagy is an emblematic example of the 'dark-side' of a rescue pathway that contributes profoundly to a pro-tumoral adaptive response. From a standpoint of treating the real human disease, only combinatorial therapy targeting autophagy with cytotoxic drugs in the adjuvant setting for GBM patients, associated with the development of less toxic and more specific autophagy inhibitors, may inhibit adaptive response and enhance the sensibility of glioma cells to conventional therapies.
ABSTRACT
Os antígenos cancer-testis (CT) são proteínas imunogênicas expressas em tecido gametogênico e em diferentes tipos de tumor, sendo considerados candidatos promissores para a imunoterapia do câncer. Entretanto, pouco se sabe sobre a função desses antígenos na tumorigênese. Em 2006, identificamos CTSP-1 como um novo antígeno CT, frequentemente expresso em vários tumores. Nesse trabalho, investigamos a função de CTSP-1 por meio da identificação de proteínas expressas em tumores de próstata e que são capazes de interagir fisicamente com esse antígeno. Demonstramos que CTSP-1 interage com a proteína CTCF em ensaios de duplo-híbrido em leveduras, pulldown e de co-localização e, em seguida, analisamos o impacto da superexpressão de CTSP-1 no controle da expressão de genes CT mediada por CTCF e na progressão do ciclo celular. Utilizando o CT NY-ESO-1 como modelo, demonstramos que a superexpressão de CTSP-1 não altera os níveis endógenos de NY-ESO-1 na linhagem celular tumoral H1299. Por outro lado, observamos que a superexpressão de CTSP-1 48h após as transfecções em H1299 induz um bloqueio do ciclo em G0/G1, reduzindo a capacidade clonogênica dessas células por um mecanismo dependente dos níveis de expressão de CTSP-1. Resultados semelhantes não foram observados em ensaios com clones superexpressando CTSP-1 estavelmente, o que sugere que eles tenham se originado de células que conseguiram escapar do bloqueio em G0/G1. Resultados preliminares sugerem que a redução da capacidade clonogênica das células H1299 que superexpressam CTSP-1 48h após as tansfecções não está associada à ocorrência de morte por apoptose.
Cancer-testis (CT) antigens are immunogenic proteins expressed in gametogenic tissues and in different histological types of tumors, being considered promising candidates for cancer immunotherapy. However, little is known about their role in tumorigenesis. In 2006, we identified CTSP-1 as a novel CT antigen, frequently expressed in different types of tumors. In this work, we investigated the functional role of CTSP-1 through the identification of proteins expressed in prostate tumors and that physically interact with this tumor antigen. We demonstrate that CTSP-1 interacts with the CTCF protein using the yeast two-hybrid system, pulldown and co-localization assays and have further analyzed the impact of CTSP-1 overexpression on the expression of CT genes mediated by CTCF and on the cell cycle progression. Using the CT antigen NY-ESO-1 as a model, we showed that the CTSP-1 overexpression does not alter the endogenous levels of NY-ESO-1 in the tumor cell line H1299. On the other hand, we observed that the overexpression of CTSP-1 in H1299 cells 48h after the transfections induces a cell cycle arrest in G0/G1 and reduces the clonogenic capacity of these cells by a mechanism dependent on the CTSP-1 expression levels. Similar results were not observed for cell clones stably overexpressing CTSP-1, suggesting that these clones have arisen from cells that managed to escape cell cycle arrest in G0/G1. Preliminary results suggest that the reduced clonogenic capacity of H1299 cells expressing CTSP-1 and analyzed 48h after the transfections is not associated with cell death by apoptosis.
Subject(s)
Cell Cycle/genetics , Molecular Biology , Prostatic Neoplasms/immunology , Protein Interaction Mapping , Antigens, Neoplasm/chemistry , Neoplastic Cells, Circulating , Sequence Analysis, ProteinABSTRACT
Os antígenos cancer-testis (CT) são proteínas imunogênicas expressas em tecido gametogênico e em diferentes tipos de tumor, sendo considerados candidatos promissores para a imunoterapia do câncer. Entretanto, pouco se sabe sobre a função desses antígenos na tumorigênese. Em 2006, identificamos CTSP-1 como um novo antígeno CT, frequentemente expresso em vários tumores. Nesse trabalho, investigamos a função de CTSP-1 por meio da identificação de proteínas expressas em tumores de próstata e que são capazes de interagir fisicamente com esse antígeno. Demonstramos que CTSP-1 interage com a proteína CTCF em ensaios de duplo-híbrido em leveduras, pulldown e de co-localização e, em seguida, analisamos o impacto da superexpressão de CTSP-1 no controle da expressão de genes CT mediada por CTCF e na progressão do ciclo celular. Utilizando o CT NY-ESO-1 como modelo, demonstramos que a superexpressão de CTSP-1 não altera os níveis endógenos de NY-ESO-1 na linhagem celular tumoral H1299. Por outro lado, observamos que a superexpressão de CTSP-1 48h após as transfecções em H1299 induz um bloqueio do ciclo em G0/G1, reduzindo a capacidade clonogênica dessas células por um mecanismo dependente dos níveis de expressão de CTSP-1. Resultados semelhantes não foram observados em ensaios com clones superexpressando CTSP-1 estavelmente, o que sugere que eles tenham se originado de células que conseguiram escapar do bloqueio em G0/G1. Resultados preliminares sugerem que a redução da capacidade clonogênica das células H1299 que superexpressam CTSP-1 48h após as tansfecções não está associada à ocorrência de morte por apoptose
Cancer-testis (CT) antigens are immunogenic proteins expressed in gametogenic tissues and in different histological types of tumors, being considered promising candidates for cancer immunotherapy. However, little is known about their role in tumorigenesis. In 2006, we identified CTSP-1 as a novel CT antigen, frequently expressed in different types of tumors. In this work, we investigated the functional role of CTSP-1 through the identification of proteins expressed in prostate tumors and that physically interact with this tumor antigen. We demonstrate that CTSP-1 interacts with the CTCF protein using the yeast two-hybrid system, pulldown and co-localization assays and have further analyzed the impact of CTSP-1 overexpression on the expression of CT genes mediated by CTCF and on the cell cycle progression. Using the CT antigen NY-ESO-1 as a model, we showed that the CTSP-1 overexpression does not alter the endogenous levels of NY-ESO-1 in the tumor cell line H1299. On the other hand, we observed that the overexpression of CTSP-1 in H1299 cells 48h after the transfections induces a cell cycle arrest in G0/G1 and reduces the clonogenic capacity of these cells by a mechanism dependent on the CTSP-1 expression levels. Similar results were not observed for cell clones stably overexpressing CTSP-1, suggesting that these clones have arisen from cells that managed to escape cell cycle arrest in G0/G1. Preliminary results suggest that the reduced clonogenic capacity of H1299 cells expressing CTSP-1 and analyzed 48h after the transfections is not associated with cell death by apoptosis
