RESUMO
Development of chemoresistance limits the clinical efficiency of platinum-based therapy. Although many resistance mechanisms have been demonstrated, genetic/molecular alterations responsible for drug resistance in the majority of clinical cases have not been identified. We analyzed three pairs of testicular germ cell tumor cell lines using Affymetrix expression microarrays and revealed a limited number of differentially expressed genes across the cell lines when comparing the parental and resistant cells. Among them, CCND1 was the most significantly differentially expressed gene. Analysis of testicular germ cell tumor clinical samples by quantitative reverse transcription PCR analysis revealed that overall expression of CCND1 was significantly higher in resistant cases compared with sensitive samples (P < 0.0001). We also found that CCND1 was dramatically overexpressed both in induced and intrinsically resistant samples of ovarian and prostate cancer. Finally combined CCND1 knockdown using small-interfering RNA and cisplatin treatment inhibited cell growth in vitro significantly more effectively than any of these single treatments. Therefore, deregulation of CCND1 may be a major cause of cisplatin resistance in testicular germ cell tumors and may also be implicated in ovarian and prostate cancers. CCND1 could be potentially used as a marker for treatment stratification and as a molecular target to improve the treatment of platinum-resistant tumors.
Assuntos
Antineoplásicos/uso terapêutico , Cisplatino/uso terapêutico , Ciclina D1/genética , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Embrionárias de Células Germinativas , Neoplasias Testiculares , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Hibridização Genômica Comparativa , Ciclina D1/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Masculino , Análise em Microsséries , Neoplasias Embrionárias de Células Germinativas/tratamento farmacológico , Neoplasias Embrionárias de Células Germinativas/patologia , Neoplasias Embrionárias de Células Germinativas/fisiopatologia , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/fisiopatologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Neoplasias da Próstata/fisiopatologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Neoplasias Testiculares/tratamento farmacológico , Neoplasias Testiculares/patologia , Neoplasias Testiculares/fisiopatologiaRESUMO
Since the introduction of cisplatin into the clinic, the treatment of patients with a variety of solid tumors including testicular germ cell tumors, ovarian and lung cancers, has dramatically improved. One of the main causes for therapeutic failure in these malignancies is the development of drug resistance. Testicular germ cell tumors (TGCTs), the most common malignancy in young men, exhibit extreme sensitivity to cisplatin-based chemotherapy, making them an ideal model for investigating the mechanisms of cisplatin chemo-sensitivity and resistance. TGCT development and pathogenesis have been well studied but little is known about the genetic background in chemo-resistant cases. We investigated genomic differences between three TGCT parental cell lines and their cisplatin resistant derivatives. Using 10K single nucleotide polymorphism (SNP) microarray analysis, we identified two small chromosomal regions with consistent copy number changes across all three pairs of resistant cell lines. These were an 8.7 Mb region at 6q26-27, which displayed consistent copy number gain and a 0.3 Mb deletion involving 4 SNPs at 10p14. Both the chromosomal gain and loss were confirmed by fluorescence in situ hybridization. The significance of these regions should be further investigated as they may contain key genes involved in the development of chemo- resistance to cisplatin-based treatment in TGCTs and other cancers.