RESUMO
PURPOSE: In this study, we aimed to identify a DNA methylation pattern suitable for prognosis assessment of muscle-invasive bladder cancer and to investigate metastasis-associated processes regulated by DNA methylation. METHODS: Genome-wide methylation analysis was performed on 23 muscle-invasive bladder tumors by microarray analysis. Validation was performed by the qAMP technique in two different patient cohorts (n = 32 and n = 100). mRNA expression was analyzed in 12 samples. Protein expression was determined using tissue microarrays of 291 patients. Bladder cancer cell lines T24 and 253JB-V were used for functional analyses. RESULTS: Microarray analyses revealed KISS1R, SEPT9 and CSAD as putative biomarkers with hypermethylation in node-positive tumors. The combination of the three genes predicted the metastatic risk with sensitivity of 73% and specificity of 71% in cohort 1, and sensitivity of 82% and specificity of 54% in cohort 2. mRNA expression differences were detected for KISS1R (p = 0.04). Protein expression of KISS1R was significantly reduced (p < 0.001). Knockdown of SEPT9v3 resulted in increased cell migration by 28% (p = 0.04) and increased invasion by 22% (p = 0.004). KISS1R overexpression resulted in decreased cell migration (25%, p = 0.1). CONCLUSIONS: We identified a methylation marker panel suitable to differentiate between patients with positive and negative lymph nodes at time of cystectomy. This enables a risk assessment for patients who potentially benefit from extended lymph node resection as well as from neoadjuvant chemotherapy and could improve the survival rates. Furthermore, we examined the impact of putative markers on tumor behavior. Hence, KISS1R and SEPT9 could represent a starting point for the development of novel therapy approaches.
Assuntos
Metilação de DNA , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologia , Idoso , Biomarcadores Tumorais/genética , Carboxiliases/biossíntese , Carboxiliases/genética , Linhagem Celular Tumoral , Estudos de Coortes , Ilhas de CpG , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Metástase Neoplásica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Kisspeptina-1/biossíntese , Receptores de Kisspeptina-1/genética , Reprodutibilidade dos Testes , Medição de Risco , Septinas/biossíntese , Septinas/genética , Neoplasias da Bexiga Urinária/metabolismoRESUMO
Identification of TAAs recognized by CD8(+) CTLs paved the way for new concepts in cancer therapy. In view of the heterogeneity of tumors and their diverse escape mechanisms, CTL-based cancer therapy largely depends on an appropriate number of TAAs. In prostate cancer, the number of antigens defined as suitable targets of CTLs remains rather limited. PSCA is widely distributed in prostate cancer. In this report, we define immunogenic peptides of PSCA which are recognized by circulating CD8(+) T cells from prostate cancer patients and able to activate CTLs in vitro. Screening the amino acid sequence of PSCA for peptides containing a binding motif for HLA-A*0201 resulted in 8 candidate peptides. Specificity and affinity of peptide binding were verified in a competition assay. Frequencies of CD8(+) T lymphocytes reactive against selected epitopes were determined in the blood of prostate cancer patients using the ELISPOT assay. Increased frequencies were revealed for CD8(+) T cells recognizing the peptides ALQPGTALL and AILALLPAL. CTLs from prostate cancer patients were raised against these 2 peptides in vitro when presented by autologous DCs. They specifically recognized peptide-pulsed T2 target cells and prostate cancer cells that were HLA-A*0201- and PSCA-positive, indicating that these peptides were naturally generated by tumor cells. These data suggest that PSCA is a promising target for the immunotherapy of prostate cancer.
