Functional characterization of the chromosome 8p tumor suppressor gene interaction with tumor microenvironment in human hepatocellular carcinoma

肝癌是全球癌症死亡的第三大原因，85%以上的肝癌病例是肝细胞癌（HCC）。HCC的高死亡率主要是由病变肝脏转移或重新形成多灶性肿瘤引起的。在先前使用基因组学和转录组学综合方法的工作中，我已经表明，在45%的患者中观察到8p染色体的缺失，并且与不良预后相关。一个预测HCC预后的10个基因“驱动”特征包含8p染色体上的6个潜在肿瘤抑制基因（TSG），真正的TSG dcl1和两个新的TSG，即SORBS3和SH2D4A。克隆原性实验、细胞迁移实验和异种移植小鼠模型证实了SH2D4A和SORBS3的抑瘤功能。因此，这种无偏倚的方法在识别预后基因标记和两个新的tsg方面是有效的。我未发表的研究表明，染色体8p缺失患者的基因表达谱表现出抑制白细胞介素-6 （IL-6）信号的表达模式。此外，我能够证明SH2D4A通过抑制STAT3信号传导起作用，而SORBS3通过增加雌激素受体α (er α)信号传导抑制IL-6信号传导。因此，本应用的第一个目的是阐明最近发现的TSGs SORBS3和SH2D4A在IL-6信号传导中的作用。IL-6信号传导已被证明在炎症，尤其是HCC的肿瘤发生和转移中起关键作用，这表明SORBS3和SH2D4A可能在功能上协同抑制IL-6信号传导。为此，我们将从功能上分析8p染色体TSGs、SORBS3和SH2D4A如何调节IL-6信号。此外，我将研究单个和多个tsg丢失的影响，并确定多个tsg丢失的功能后果。为了阐明SORBS3和SH2D4A对肿瘤微环境的影响，我们将对原位小鼠模型和HCC患者样本进行肿瘤细胞生长、免疫细胞浸润和细胞因子谱的研究。这些发现可能会导致SORBS3和SH2D4A表达降低的HCC患者开发新的方法，从而改善HCC治疗和患者生存率。

Liver cancer is the third leading cause of cancer death worldwide and more than 85% of all liver cancer cases are hepatocellular carcinoma (HCC). The high mortality rate of HCC is mainly caused by metastasis or by de novo multifocal tumor formation in the diseased liver. In previous work using an integrative genomic and transcriptomic approach, I have shown that loss of chromosome 8p is observed in 45% of patients and is associated with poor outcome. A 10-gene 'driver' signature that predicts outcome in HCC contains six potential tumor suppressor genes (TSGs) on chromosome 8p, the bona fide TSG DLC1 and two novel TSGs, namely SORBS3 and SH2D4A. Clonogenicity assays, cell migration assays and xenograft mouse models confirmed the tumor suppressor function of SH2D4A and SORBS3. Therefore, this unbiased approach was effective in identifying a prognostic gene signature and two novel TSGs. My unpublished studies show that the gene expression profiles of patients with chromosome 8p deletion exhibit expression patterns characteristic of inhibition of interleukin-6 (IL-6) signaling. In addition, I was able to show that SH2D4A functions by repressing STAT3 signaling, whereas, SORBS3 inhibits IL-6 signaling through increase of estrogen receptor alpha (ERalpha) signaling. Thus, the first objective of this application is to elucidate the role of the recently identified TSGs SORBS3 and SH2D4A in IL-6 signaling. IL-6 signaling has been shown to be critically involved in inflammation, and especially in tumorigenesis and metastasis of HCC suggesting that SORBS3 and SH2D4A may functionally collaborate to inhibit IL-6 signaling. To this end, it will be functionally analyzed how chromosome 8p TSGs SORBS3 and SH2D4A modulate IL-6 signaling. In addition, I will investigate the effect of loss of a single versus multiple TSGs and determine the functional consequence of the loss of multiple TSGs. To elucidate the influence of SORBS3 and SH2D4A on the tumor microenvironment, an orthotopic mouse model and HCC patient samples will be studied in regard to tumor cell growth, immune cell infiltration and cytokine profiles. These findings may lead to the development of novel approaches for HCC patients with reduced SORBS3 and SH2D4A expression, thus, leading to improved HCC treatment and patient survival.