RESUMO
Although many cancers initially respond to cisplatin (CDDP)-based chemotherapy, resistance frequently develops. Insulin-like growth factor-binding protein-3 (IGFBP-3) silencing by promoter methylation is involved in the CDDP-acquired resistance process in non-small cell lung cancer (NSCLC) patients. Our purpose is to design a translational-based profile to predict resistance in NSCLC by studying the role of IGFBP-3 in the phosphatidyl inositol 3-kinase (PI3K) signaling pathway. We have first examined the relationship between IGFBP-3 expression regulated by promoter methylation and activation of the epidermal growth factor receptor (EGFR), insulin-like growth factor-I receptor (IGFIR) and PI3K/AKT pathways in 10 human cancer cell lines and 25 NSCLC patients with known IGFBP-3 methylation status and response to CDDP. Then, to provide a helpful tool that enables clinicians to identify patients with a potential response to CDDP, we have calculated the association between our diagnostic test and the true outcome of analyzed samples in terms of cisplatin IC50; the inhibitory concentration that kills 50% of the cell population. Our results suggest that loss of IGFBP-3 expression by promoter methylation in tumor cells treated with CDDP may activate the PI3K/AKT pathway through the specific derepression of IGFIR signaling, inducing resistance to CDDP. This study also provides a predictive test for clinical practice with an accuracy and precision of 0.84 and 0.9, respectively, (P=0.0062). We present a biomarker test that could provide clinicians with a robust tool with which to decide on the use of CDDP, improving patient clinical outcomes.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Cisplatino/farmacologia , Metilação de DNA , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor IGF Tipo 1/metabolismo , Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Receptores ErbB/genética , Receptores ErbB/metabolismo , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/biossíntese , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/deficiência , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Fosforilação , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-akt/genética , Receptor IGF Tipo 1/genética , Transdução de Sinais , TransfecçãoRESUMO
MicroRNAs (miRNAs) are regulatory, non-coding RNAs that are approximately 22 nucleotides in length. Nearly 1000 unique miRNAs encoded in the human genome have been identified, shedding new light on the posttranscriptional regulation of more than one-third of human genes. These miRNAs are involved in numerous biological processes, including development, differentiation, apoptosis, homeostasis and stem cell biology. Aberrant miRNA expression patterns also play a substantial role in carcinogenesis. It is believed that genetic and epigenetic regulation is responsible for changes in miRNA expression in cancer development, however the exact mechanisms remain unclear. miRNAs are involved in almost all aspects of cancer biology such as apoptosis, invasion, metastasis and angiogenesis. Thanks to this wide range of biological functions, the analysis of changes in overall miRNA expression occurring within human tumours has helped identify miRNA signatures associated with diagnosis, staging, progression, prognosis and response to treatment. This positions miRNA- targeting therapeutics as a novel and promising tool for cancer treatment (AU)
Assuntos
Humanos , Masculino , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Epigenômica/métodos , Epigenômica/organização & administração , MicroRNAs/fisiologia , Biomarcadores Tumorais/genética , Oncologia/métodos , Oncologia/organização & administração , Oncologia/normasRESUMO
Cisplatin-based chemotherapy is the paradigm of non-small-cell lung cancer (NSCLC) treatment; however, it also induces de novo DNA-hypermethylation, a process that may be involved in the development of drug-resistant phenotypes by inactivating genes required for drug-cytotoxicity. By using an expression microarray analysis, we aimed to identify those genes reactivated in a set of two cisplatin (CDDP) resistant and sensitive NSCLC cell lines after epigenetic treatment. Gene expression, promoter methylation and CDDP-chemoresponse were further analyzed in three matched sets of sensitive/resistant cell lines, 23 human cancer cell lines and 36 NSCLC specimens. Results revealed specific silencing by promoter hypermethylation of IGFBP-3 in CDDP resistant cells, whereas IGFBP-3 siRNA interference, induced resistance to CDDP in sensitive cells (P<0.001). In addition, we found a strong correlation between methylation status and CDDP response in tumor specimens (P<0.001). Thus, stage I patients, whose tumors harbor an unmethylated promoter, had a trend towards increased disease-free survival (DFS). We report that a loss of IGFBP-3 expression, mediated by promoter-hypermethylation, results in a reduction of tumor cell sensitivity to cisplatin in NSCLC. Basal methylation status of IGFBP-3 before treatment may be a clinical biomarker and a predictor of the chemotherapy outcome, helping to identify patients who are most likely to benefit from CDDP therapy alone or in combination with epigenetic treatment.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Cisplatino/farmacologia , Metilação de DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Neoplasias Pulmonares/genética , Antineoplásicos/farmacologia , Azacitidina/farmacologia , Sequência de Bases , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HT29 , Células HeLa , Humanos , Ácidos Hidroxâmicos/farmacologia , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/deficiência , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas/genética , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais CultivadasRESUMO
The nuclear factor kappa B (NFkappaB) signalling pathway regulates the expression of hundreds of genes that are involved in different cellular processes such as cell proliferation, survival, stress responses, cellular immunity and inflammation. Its aberrant regulation is involved in several pathologies, but its relevance in cellular transformation and cancer development has been extensively studied. Mutations in the core components of NFkappaB as well as in the cellular machinery that regulates its activation have been found in many types of tumours. On the other hand, its role in promoting cell survival is an important obstacle in many cancer therapies. The development of chemical inhibitors that block NFkappaB activation acting either directly on IKKs or on the proteosome machinery has shown antitumour and proapoptotic activity both in preclinical and clinical studies (AU)
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