RESUMO
BACKGROUND: Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children. The Hedgehog (HH) pathway is known to develop an oncogenic role in RMS. However, the molecular mechanism that drives activation of the pathway in RMS is not well understood. METHODS: The expression of HH ligands was studied by qPCR, western blot and immunohistochemistry. Functional and animal model studies were carried out with cells transduced with shRNAs against HH ligands or treated with HH-specific inhibitors (Vismodegib and MEDI-5304). Finally, the molecular characterisation of an off-target effect of Vismodegib was also made. RESULTS: The results showed a prominent expression of HH ligands supporting an autocrine ligand-dependent activation of the pathway. A comparison of pharmacologic Smoothened inhibition (Vismodegib) and HH ligand blocking (MEDI-5304) is also provided. Interestingly, a first description of pernicious off-target effect of Vismodegib is also reported. CONCLUSIONS: The clarification of the HH pathway activation mechanism in RMS opens a door for targeted therapies against HH ligands as a possible alternative in the future development of better treatment protocols. Moreover, the description of a pernicious off-target effect of Vismodegib, via unfolded protein response activation, may mechanistically explain its previously reported inefficiency in several ligand-dependent cancers.
Assuntos
Carcinogênese/patologia , Proliferação de Células , Proteínas Hedgehog/metabolismo , Rabdomiossarcoma/patologia , Fatores de Transcrição/metabolismo , Animais , Apoptose , Carcinogênese/genética , Carcinogênese/metabolismo , Movimento Celular , Feminino , Proteínas Hedgehog/genética , Humanos , Ligantes , Camundongos , Camundongos SCID , Rabdomiossarcoma/genética , Rabdomiossarcoma/metabolismo , Transdução de Sinais , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The prognosis of patients with metastatic rhabdomyosarcoma (RMS), the most common type of soft tissue sarcoma in children, is poor and no strategies have been identified to improve their dismal prognosis. Alpha-9 integrin (ITGA9) plays a particularly crucial role in cancer progression and invasiveness. Despite the consensus on the remarkable pro-oncogenic potential of this protein, the miRNA-mediated regulation of ITGA9 has barely been studied to date. In the present study, miR-7 and miR-324-5p were selected as the best candidates after a screening to find ITGA9 regulators, and their effects on cell proliferation and invasion in RMS are described and characterized for the first time. Interestingly, the overexpression of both miRNA produced a clear impairment of cell proliferation, while miR-7 also induced a remarkable drop in cell invasion. Furthermore, the stable overexpression of both miRNA was found to reduce tumor growth in orthotopic RMS models and miR-7 was able to impair metastatic lung colonization. Consequently, we conclude that miR-7 and miR-324-5p show anti-oncogenic and anti-metastatic potential, thereby opening up the possibility of being used as novel therapeutic tools to avoid RMS progression.
Assuntos
Integrinas/genética , MicroRNAs/genética , Rabdomiossarcoma/genética , Rabdomiossarcoma/patologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Doxiciclina/farmacologia , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos SCID , Fosforilação , RNA Interferente Pequeno , Rabdomiossarcoma/tratamento farmacológico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The use of preclinical models is essential in translational cancer research and especially important in pediatric cancer given the low incidence of each particular type of cancer. Cell line cultures have led to significant advances in cancer biology. However, cell lines have adapted to growth in artificial culture conditions, thereby undergoing genetic and phenotypic changes which may hinder the translational application. Tumor grafts developed in mice from patient tumor tissues, generally known as patient-derived xenografts (PDXs), are interesting alternative approaches to reproducing the biology of the original tumor. This review is focused on highlighting the interest of PDX models in pediatric cancer research and supporting strategies of personalized medicine. This review provides: (1) a description of the background of PDX in cancer, (2) the particular case of PDX in pediatric cancer, (3) how PDX can improve personalized medicine strategies, (4) new methods to increase engraftment, and, finally, (5) concluding remarks.
Assuntos
Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Medicina de Precisão , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Humanos , Camundongos , Neoplasias/genética , Pesquisa Translacional BiomédicaRESUMO
Neuroblastoma (NB) is a neoplasm of the sympathetic nervous system, and is the most common solid tumor of infancy. NBs are very heterogeneous, with a clinical course ranging from spontaneous regression to resistance to all current forms of treatment. High-risk patients need intense chemotherapy, and only 30-40% will be cured. Relapsed or metastatic tumors acquire multi-drug resistance, raising the need for alternative treatments. Owing to the diverse mechanisms that are responsible of NB chemoresistance, we aimed to target epigenetic factors that control multiple pathways to bypass therapy resistance. We found that the SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4 (SMARCA4/BRG1) was consistently upregulated in advanced stages of NB, with high BRG1 levels being indicative of poor outcome. Loss-of-function experiments in vitro and in vivo showed that BRG1 is essential for the proliferation of NB cells. Furthermore, whole-genome transcriptome analysis revealed that BRG1 controls the expression of key elements of oncogenic pathways such as PI3K/AKT and BCL2, which offers a promising new combination therapy for high-risk NB.
Assuntos
Sobrevivência Celular/genética , DNA Helicases/genética , Neuroblastoma/genética , Proteínas Nucleares/genética , Fatores de Transcrição/genética , Transcriptoma/genética , Morte Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Neuroblastoma/patologia , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Transdução de Sinais/genéticaRESUMO
The use of preclinical models is essential in translational cancer research and especially important in pediatric cancer given the low incidence of each particular type of cancer. Cell line cultures have led to significant advances in cancer biology. However, cell lines have adapted to growth in artificial culture conditions, thereby undergoing genetic and phenotypic changes which may hinder the translational application. Tumor grafts developed in mice from patient tumor tissues, generally known as patient-derived xenografts (PDXs), are interesting alternative approaches to reproducing the biology of the original tumor. This review is focused on highlighting the interest of PDX models in pediatric cancer research and supporting strategies of personalized medicine. This review provides: (1) a description of the background of PDX in cancer, (2) the particular case of PDX in pediatric cancer, (3) how PDX can improve personalized medicine strategies, (4) new methods to increase engraftment, and, finally, (5) concluding remarks (AU)
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