Integrative Molecular Profiling of Human Pancreatic Cancer

这个正在进行的项目利用基于组学的策略来研究胰腺癌进展和疾病侵袭性的潜在机制，以确定候选的治疗靶点。在我们的一项研究中，我们试图获得对高和低MIF表达的肿瘤的全面分子洞察，并确定推动肿瘤进展的关键MIF信号通路，我们分析了编码和非编码基因在多个PDAC患者队列中高(中)和低(低于中)MIF表达的肿瘤中的表达。已确定的关键基因和途径与患者的生存有关，并使用细胞系、基因工程小鼠模型和PDAC患者队列从机制、功能和临床上进行了表征。我们报道了一种新的MIF驱动的信号通路的机制、功能和临床证据，该通路抑制了以前未描述的潜在肿瘤抑制因子，核受体亚家族-3，C组，成员-2(NR3C2)，导致PDAC疾病侵袭性增强和生存率降低。在机制上，MIF上调miR-301b，从而靶向并抑制NR3C2的表达。MIF高表达的肿瘤表现为miR-301b高表达和NR3C2低表达。此外，肿瘤中NR3C2表达较低的患者在PDAC患者的多个独立队列中的存活率较低。这些发现发现了一个关键的MIF诱导的信号通路，它促进了PDAC中的肿瘤进展和疾病侵袭性。这项研究还证实了NR3C2，一个盐皮质激素受体基因，可能是疾病进展的抑制因子。我们目前正在研究NR3C2在PDAC中的机制作用。此外，在我们最初的努力中，我们比较了存活率极低(小于7个月)的早期PDAC患者和手术切除后存活2年或更长时间的患者的肿瘤的基因表达谱。在两组差异表达的1,820个基因中，炎症基因网络占主导地位。NOSTRIN的低表达与显着的低存活率相关，表明其在疾病进展中具有潜在的肿瘤抑制作用。NOSTRIN使内皮型一氧化氮合酶(eNOS/NOS3)失活，并抑制一氧化氮(NO)的产生。此外，miR-221与NOSTRIN的3‘非编码区结合并抑制其表达，而miR-221的表达增加与PDAC的生存不良有关。我们的发现与NOSTRIN是疾病侵袭性的潜在负调节因子的假设是一致的，这可能是设计PDAC改进治疗策略的靶点。我们正在继续研究NOSTRIN在PDAC中的NO依赖和NO独立的机制作用。如前所述，基于基因组、转录组和代谢谱的差异，已经报道了胰腺导管腺癌的分子亚群，然而，在这些亚群中具有治疗意义的特定分子靶点还没有明确的定义。我们正在进行的研究正在调查一个高度侵袭性的亚组，以确定驱动肿瘤进展和疾病侵袭性的关键机制，这些机制可能具有潜在的治疗意义。在我们的代谢组学研究中，我们已经表明，涉及脂肪酶和一组独特的游离脂肪酸的脂解途径的障碍，可能在胰腺癌的发生和发展中发挥重要作用，并为治疗干预提供潜在的靶点。我们目前正在研究炎症信号通路在胰腺癌代谢重编程调节中的作用。

This ongoing project utilizes omics-based strategies for investigating the underlying mechanisms of pancreatic cancer progression and disease aggressiveness to identify candidate therapeutic targets. In one of our studies we tried to attain a comprehensive molecular insight into tumors with high- and low-MIF expression and to identify key MIF-signaling pathways that drive tumor progression, we analyzed the expression of coding and non-coding genes in high (median) and low (less than median) MIF-expressing tumors in multiple cohorts of PDAC patients. The identified key genes and pathways were linked to patients' survival and were mechanistically, functionally and clinically characterized using cell lines, genetically engineered mouse model and PDAC patient cohorts. We reported mechanistic, functional and clinical evidence of a novel MIF-driven signaling pathway that inhibits a previously undescribed potential tumor suppressor, nuclear-receptor-subfamily-3, group-C, member-2 (NR3C2), leading to enhanced disease aggressiveness and poorer survival in PDAC. Mechanistically, MIF upregulated miR-301b, which then targeted and suppressed NR3C2 expression. Tumors with a higher MIF expression showed an elevated miR-301b and a reduced NR3C2 expression. Additionally, patients with a lower NR3C2 expression in tumors showed poorer survival in multiple independent cohorts of PDAC patients. These findings discovered a key MIF-induced signaling pathway, which enhances tumor progression and disease aggressiveness in PDAC. This study also identified NR3C2, a mineralocorticoid receptor gene, as a putative inhibitor of disease progression. We are currently investigating the mechanistic role of NR3C2 in PDAC. Furthermore, in our initial effort to characterize tumors from early stage resected PDAC patients with markedly different survival, we compared gene expression profiles in tumors from early stage PDAC cases with extremely poor survival (less than 7 months) and those surviving 2 years or more following surgical resection. Inflammatory gene network dominated among 1,820 differentially expressed genes between the two groups. A lower expression of NOSTRIN was associated with significantly poor survival indicating its potential tumor inhibitory role in disease progression. NOSTRIN inactivated endothelial NOS (eNOS/NOS3) and inhibited the production of nitric oxide (NO). Furthermore, miR-221, bound to the 3'UTR of NOSTRIN and suppressed its expression, and an increased miR-221 expression associated with poor survival in PDAC. Our findings are consistent with the hypothesis that NOSTRIN is a potential negative regulator of disease aggressiveness, which may be targeted for designing improved treatment strategy in PDAC. We are continuing our investigation into the NO-dependent and NO-independent mechanistic role of NOSTRIN in PDAC. As mentioned earlier, molecular subgroups of pancreatic ductal adenocarcinoma have been reported based on the difference in genomic, transcriptomics and metabolic profiling, however, specific molecular targets with therapeutic significance in these subgroups are yet to be clearly defined. Our ongoing study is investigating a highly aggressive subgroup to define key mechanisms driving tumor progression and disease aggressiveness that may be targeted with potential therapeutic significance. In our metabolomic studies, we have shown that impairment in a lipolytic pathway involving lipases and a unique set of free fatty acids, may play an important role in the development and progression of pancreatic cancer and provide potential targets for therapeutic intervention. We are currently investigating the role of inflammatory signaling pathways in the regulation of metabolic reprogramming in pancreatic cancer.