Dept. of General and Visceral Surgery, University Hospital of Muenster, Waldeyerstr, 1, Muenster, Germany.
BMC Cancer. 2010 Oct 12;10:549. doi: 10.1186/1471-2407-10-549.
Early metastasis and infiltration are survival limiting characteristics of pancreatic ductal adenocarcinoma (PDAC). Thus, PDAC is likely to harbor alterations in metastasis suppressor genes that may provide novel diagnostic and therapeutic opportunities. This study investigates a panel of metastasis suppressor genes in correlation to PDAC phenotype and examines promoter methylation for regulatory influence on metastasis suppressor gene expression and for its potential as a diagnostic tool.
Metastatic and invasive potential of 16 PDAC cell lines were quantified in an orthotopic mouse model and mRNA expression of 11 metastasis suppressor genes determined by quantitative RT-PCR. Analysis for promoter methylation was performed using methylation specific PCR and bisulfite sequencing PCR. Protein expression was determined by Western blot.
In general, higher metastasis suppressor gene mRNA expression was not consistent with less aggressive phenotypes of PDAC. Instead, mRNA overexpression of several metastasis suppressor genes was found in PDAC cell lines vs. normal pancreatic RNA. Of the investigated metastasis suppressor genes, only higher AKAP12 mRNA expression was correlated with decreased metastasis (P < 0.05) and invasion scores (P < 0.01) while higher SERPINB5 mRNA expression was correlated with increased metastasis scores (P < 0.05). Both genes' promoters showed methylation, but only increased SERPINB5 methylation was associated with loss of mRNA and protein expression (P < 0.05). SERPINB5 methylation was also directly correlated to decreased metastasis scores (P < 0.05).
AKAP12 mRNA expression was correlated to attenuated invasive and metastatic potential and may be associated with less aggressive phenotypes of PDAC while no such evidence was obtained for the remaining metastasis suppressor genes. Increased SERPINB5 mRNA expression was correlated to increased metastasis and mRNA expression was regulated by methylation. Thus, SERPINB5 methylation was directly correlated to metastasis scores and may provide a diagnostic tool for PDAC.
早期转移和浸润是胰腺导管腺癌（PDAC）生存受限的特征。因此，PDAC 可能存在转移抑制基因的改变，这可能为诊断和治疗提供新的机会。本研究调查了一组转移抑制基因与 PDAC 表型的相关性，并检查了启动子甲基化对转移抑制基因表达的调控影响及其作为诊断工具的潜力。
在原位小鼠模型中定量测定 16 种 PDAC 细胞系的转移和侵袭潜力，并通过定量 RT-PCR 测定 11 种转移抑制基因的 mRNA 表达。使用甲基化特异性 PCR 和亚硫酸氢盐测序 PCR 进行启动子甲基化分析。通过 Western blot 确定蛋白表达。
一般来说，较高的转移抑制基因 mRNA 表达与 PDAC 的侵袭性表型不一致。相反，在 PDAC 细胞系与正常胰腺 RNA 相比，几种转移抑制基因的 mRNA 过表达。在所研究的转移抑制基因中，只有 AKAP12mRNA 表达较高与转移（P < 0.05）和侵袭评分（P < 0.01）降低相关，而 SERPINB5mRNA 表达较高与转移评分升高相关（P < 0.05）。这两个基因的启动子都显示出甲基化，但只有 SERPINB5 甲基化的增加与 mRNA 和蛋白表达的丧失相关（P < 0.05）。SERPINB5 甲基化也与转移评分的降低直接相关（P < 0.05）。
AKAP12mRNA 表达与侵袭和转移潜能减弱相关，可能与 PDAC 侵袭性表型减弱有关，而其余转移抑制基因则没有得到证实。SERPINB5mRNA 表达增加与转移增加相关，mRNA 表达受甲基化调节。因此，SERPINB5 甲基化与转移评分直接相关，可能为 PDAC 提供一种诊断工具。
