RESUMO
Approximately 20% of patients with bladder cancer are diagnosed with muscle-invasive disease (MIBC). The treatment involves radical cystectomy, but almost 50% of patients with MIBC eventually relapse and develop metastasis. The use of platinum-based chemotherapy in the neoadjuvant setting or for metastatic patients has been shown to improve the overall survival in a subset of patients. Unfortunately, no biomarkers are available to select patients with MIBC who will benefit from chemotherapy or to monitor the efficacy of the treatment. Recently, long noncoding RNAs (lncRNAs) were shown to regulate a variety of processes involved in the development and progression of cancer, including bladder cancer. Moreover, several lncRNAs have been shown to play a role in chemotherapy resistance. Here, we analyzed lncRNA expression associated with response to platinum-based chemotherapy in metastatic MIBC using data from the MiTranscriptome lncRNA expression database. Expression of the lncRNA, LINC00857, was found to be upregulated in tumors from patients that did not respond to platinum-based chemotherapy. Moreover, high expression of LINC00857 is correlated with shorter recurrence-free and overall survival of patients with MIBC. Knockdown of LINC00857 significantly decreased cell viability of bladder cancer cell lines through the induction of apoptosis. Furthermore, LINC00857 knockdown sensitized UM-UC-3 and T24 bladder cancer cells to cisplatin, via the negative regulation of the LMAN1 gene. Our data indicate that LINC00857 plays an important role in the regulation of response to platinum-based chemotherapy. LINC00857 potentially could serve as a novel prognostic and predictive biomarker and might be a therapeutic target to overcome cisplatin resistance in patients with MIBC.
RESUMO
Reversing epithelial-to-mesenchymal transition (EMT) in cancer cells has been widely considered as an approach to combat cancer progression and therapeutic resistance, but a limited number of broadly comprehensive investigations of miRNAs involved in this process have been conducted. In this study, we screened a library of 1120 miRNA for their ability to transcriptionally activate the E-cadherin gene CDH1 in a promoter reporter assay as a measure of EMT reversal. By this approach, we defined miR-520f as a novel EMT-reversing miRNA. miR-520f expression was sufficient to restore endogenous levels of E-cadherin in cancer cell lines exhibiting strong or intermediate mesenchymal phenotypes. In parallel, miR-520f inhibited invasive behavior in multiple cancer cell systems and reduced metastasis in an experimental mouse model of lung metastasis. Mechanistically, miR-520f inhibited tumor cell invasion by directly targeting ADAM9, the TGFß receptor TGFBR2 and the EMT inducers ZEB1, ZEB2, and the snail transcriptional repressor SNAI2, each crucial factors in mediating EMT. Collectively, our results show that miR-520f exerts anti-invasive and antimetastatic effects in vitro and in vivo, warranting further study in clinical settings. Cancer Res; 77(8); 2008-17. ©2017 AACR.
Assuntos
Proteínas ADAM/genética , Transição Epitelial-Mesenquimal/genética , Proteínas de Membrana/genética , MicroRNAs/administração & dosagem , MicroRNAs/genética , Neoplasias Pancreáticas/terapia , Proteínas Serina-Treonina Quinases/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Neoplasias da Bexiga Urinária/terapia , Proteínas ADAM/antagonistas & inibidores , Animais , Antígenos CD , Caderinas/genética , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Humanos , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Regiões Promotoras Genéticas , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Fatores de Crescimento Transformadores beta/antagonistas & inibidores , Ativação Transcricional , Transfecção , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologiaRESUMO
The prognosis of pancreatic cancer patients is very poor, with a 5-year survival of less than 6%. Therefore, there is an urgent need for new therapeutic options in pancreatic cancer. In the past years it became evident that deregulation of epigenetic mechanisms plays an important role in pancreatic carcinogenesis. This review focuses on the exploitation of drugs that alter histone modifications, DNA methylation and microRNA expression as options for the treatment of pancreatic cancer.