Identification of therapeutic sensitivities and pathways driving adrenocortical carcinoma

肾上腺皮质肿瘤相对常见，患病率为1-10%。大多数是良性的，然而，在极少数情况下，肾上腺皮质癌（ACC）可发展为侵袭性的，5年预后差。了解驱动ACC进展的途径对于开发更有效的治疗方法和预测个体结果至关重要。下一代测序研究揭示了人类疾病中存在的复发性改变。这些研究已经确定WNT信号通路的突变，包括CTNNB1的激活突变，是最常见的改变之一。小鼠研究表明，激活Ctnnb1突变可引起肾上腺皮质肿瘤形成，突出了该模型研究肾上腺肿瘤发生的价值。我们发现HOXB9基因在小鼠肾上腺皮质发育的早期阶段表达，并在激活Ctnnb1突变驱动的肾上腺肿瘤中上调。人类ACC肿瘤也显示HOXB9表达上调，这与WNT信号失调和生存频率降低相关，表明该基因在致癌过程中起作用。在初步研究中，我们培育了Hoxb9在发育和成年肾上腺皮质细胞中表达升高的转基因小鼠。含有这种转基因和激活Ctnnb1突变的小鼠表现出肿瘤发生的加速，其特征是细胞增殖和肿瘤重量增加，细胞外观呈肿瘤未分化的纺锤形表型。这些研究表明，HOXB9可以与WNT信号通路合作，驱动肾上腺肿瘤的进展。该项目的目的是研究HOXB9驱动肿瘤进展的细胞和分子机制和途径。使用体外和体内方法，我们将确定该基因在肾上腺皮质肿瘤细胞增殖和存活，细胞命运和分化中的作用。我们将确定与HOXB9相关的分子通路，包括其与WNT信号通路的相互作用。该项目的另一个目的是表征与肾上腺皮质癌中WNT信号通路相关的药物敏感性。利用各种WNT信号失调的ACC模型，我们将研究靶向该通路的药物对体内和体外细胞存活的影响。通过高通量药物文库筛选，我们将确定能够提高这些靶向化合物有效性的联合疗法。在一种补充方法中，我们将使用RNA干扰筛选来识别WNT信号通路中的关键节点，当抑制WNT信号通路时，这些节点在ACC中实现治疗反应。提出的研究的最终目标是确定肾上腺皮质癌发生的新途径和药物敏感性，这将提供重要的信息，有助于开发治疗这种罕见和侵袭性疾病的临床疗法。

Tumours of the adrenal cortex are relatively common with a prevalence of 1-10%. Most of these are benign, however, in rare case adrenocortical carcinoma (ACC) can develop which is aggressive and has a poor 5 year prognosis. Understanding pathways that drive ACC progression is essential to the development of more effective treatments and for the prediction of individual outcomes. Next generation sequencing studies have revealed recurrent alterations present in human disease. These studies have identified mutations in the WNT signalling pathway, including activating mutations in CTNNB1, to be one of the most frequent alterations. Studies in mice have shown that activating mutations in Ctnnb1 can give rise to tumour formation in the adrenal cortex, highlighting the value of this model to study adrenal tumourigenesis. We have identified HOXB9 as a gene expressed in the early stages of adrenal cortex development and upregulated in adrenal tumours driven by activating Ctnnb1 mutations in mice. Human ACC tumours also show upregulation of HOXB9 expression that correlates with WNT signalling dysregulation and decreased survival frequency suggesting a role for this gene in carcinogenesis. In preliminary studies, we have generated transgenic mice with elevated Hoxb9 expression in developing and adult adrenal cortical cells. Mice that contain this transgene and an activating Ctnnb1 mutation showed acceleration of tumourigenesis characterised by increased cell proliferation and tumour weight and in the appearance of cells with a neoplastic undifferentiated spindle shaped phenotype. These studies indicate that HOXB9 can cooperate with the WNT signalling pathway to drive adrenal tumour progression. The aim of this project is to investigate the cellular and molecular mechanisms and pathways by which HOXB9 drives tumour progression. Using in vitro and in vivo approaches we will determine the role of this gene in adrenocortical tumour cell proliferation and survival, cell fate and differentiation. We will identify the molecular pathways associated with HOXB9, including its interaction with the WNT signalling pathway.An additional aim of this project is to characterise the drug sensitivities associated with the WNT signalling pathway in adrenocortical carcinoma. Using various ACC models with dysregulated WNT signalling we will investigate the effect of drugs targeting this pathway on cell survival in vivo and in vitro. Using high throughput drug library screens we will identify combinations therapies that will increase the effectiveness of these targeted compounds. In a complementary approach, we will use RNA interference screens to identify the key nodal points in the WNT signalling pathway that when inhibited achieve a therapeutic response in ACC. The ultimate goal of the studies proposed is to identify novel pathways and drug sensitivities in adrenocortical carcinogenesis that will provide important information that will aid in the development of clinical therapies to treat this rare and aggressive disease.