gamma-OHPdG as a prognostic biomarker of HCC recurrence and its prevention

肝细胞癌（HCC）是全世界癌症相关死亡的第三大原因， 主要是因为它的预后差。一种有效和可靠的基于机制的预后 生物标志物是迫切需要的。γ-羟基-1，N2-丙脱氧鸟苷（γ-OHPdG）是一种具有生物活性的脱氧鸟苷， 脂质过氧化（LPO）产生的内源性致突变DNA加合物。我们研究了 肝γ-OHPdG与肝癌发生的关系 γ-OHPdG作为肝癌复发预后生物标志物的潜力 手术切除后。对着色性干皮病A组进行肿瘤生物学测定 基因敲除小鼠（Xpa-/-）、注射二乙基亚硝胺（DEN）的小鼠和Long-Evans Cinnamon (LEC)大鼠，并且都易于发生HCC。我们发现增加的γ-OHPdG 在所有三种动物模型中，肝DNA水平与HCC发展相关。此外，委员会认为， Theaphenon E处理显著降低Xpa-/-小鼠肝DNA中γ-OHPdG水平， 小鼠，并且这种降低与其减少HCC的显著效果密切相关 发病率（从100%到14%）。Theaphenon E也有效地抑制了HCC的发展， 注射DEN的小鼠。使用来自90例和45例HCC的两组独立的临床样本 我们的研究表明，肝癌活检标本中γ-OHPdG水平较高， 通过免疫组织化学染色检测，与低生存率密切相关 （p<0.0001）和低无复发生存率（p=0.007）。这些结果支持γ- OHPdG作为预测HCC风险的生物学相关生物标志物的前景及其应用 复发在本提案中，我们在目标1中提出，将这些令人兴奋的发现扩展到包括 更大的患者人群，以进一步解决γ-OHPdG与（1） HCC的潜在病因，例如HBV、HCV、酒精性肝病和非酒精性肝病 脂肪性肝炎（NASH）和（2）侵袭性的临床预测因子，例如分化、HCC 分期、血管侵犯和肝外转移。我们还想将其水平与 邻近非肿瘤组织的那些，并检查肿瘤突变负荷。目标2 3.建立一种非侵入性检测尿液中γ-OHPdG的方法。我们 一个假设是，尿液中的加合物水平反映了肝脏DNA中的水平。在目标4中，我们将 一项使用Polyphenon E（FDA批准的Theaphenon E的等效物）的干预试验， 预防肝γ-OHPdG升高的高危患者的HCC复发。我们的长期 我们的目标是开发γ-OHPdG作为HCC及其复发的预后生物标志物， 干预试验。

Hepatocellular carcinoma (HCC) is the third leading cause of cancer–related deaths worldwide, mainly because of its poor prognosis. A valid and reliable mechanism-based prognostic biomarker is urgently needed. γ-Hydroxy-1,N2-propanodeoxyguanosine (γ-OHPdG) is an endogenous mutagenic DNA adduct derived from lipid peroxidation (LPO). We studied the relationship between hepatic γ-OHPdG and hepatocarcinogenesis in three animal models and the potential of γ-OHPdG to be used as a prognostic biomarker for recurrence in HCC patients after surgical resection. Tumor bioassays were conducted in Xeroderma pigmentosum group A knockout mice (Xpa-/-), diethylnitrosamine (DEN)-injected mice, and Long-Evans Cinnamon (LEC) rats, and all are prone to HCC development. We found that the increased γ-OHPdG levels in liver DNA correlated with HCC development in all three animal models. Furthermore, Theaphenon E treatment significantly decreased γ-OHPdG levels in the liver DNA of Xpa-/- mice, and this decrease was closely associated with its remarkable effect to reduce HCC incidence (from 100% to 14%). Theaphenon E also effectively inhibited HCC development in DEN-injected mice. Using two independent sets of clinical samples from 90 and 45 HCC patients, our studies demonstrated that higher levels of γ-OHPdG in HCC biopsy specimens, detected by immunohistochemical staining , are strongly associated with low survival (p<0.0001) and low recurrence-free survival (p=0.007), respectively. These results support γ- OHPdG as a promising biologically relevant biomarker for predicting the risk of HCC and its recurrence. In this proposal, we propose in Aim 1 to extend these exciting findings to include a larger patient population to further address questions on γ-OHPdG’s relationships with (1) the underlying etiology of HCC, e.g. HBV, HCV, alcoholic liver disease, and non-alcoholic steatohepatitis (NASH) and (2) clinical predictors for aggressiveness, e.g. differentiation, HCC stage, vascular invasion, and extra-hepatic metastasis. We also want to compare its levels with those of the adjacent non-tumorous tissues and to examine the tumor mutation load. In Aims 2 and 3, we will develop a non-invasive method for detecting γ-OHPdG in human urine. Our hypothesis is that the adduct levels in urine reflect those in liver DNA. In Aim 4, we will conduct an intervention trial with Polyphenon E, an FDA approved equivalent of Theaphenon E, to prevent HCC recurrence in high risk patients identified with high liver γ-OHPdG. Our long-term goal is to develop γ-OHPdG as a prognostic biomarker for HCC and its recurrence for intervention trials.