Notch信号阻断剂抑制IL-17介导胰腺炎癌转化的机制研究

Pancreatic cancer is one of the most malignant neoplasm, which carries extremely poor prognosis. The current therapeutic methods are unable to control the disease completely. Clinically, It is common that the chronic pancreatitis could transform into pancreatic cancer, which suggesting that targeting at the inflammation-to-neoplasm transformation may have anti-tumor effects. It is known that both interleukin-17 (IL-17) and Notch signaling participate in the inflammation-to-neoplasm transformation. Pharmacological inhibition of either IL-17 or Notch signaling decelerates pancreatic malignancy progression. Previously, our group found that Notch signaling inhibitor prevented immune cell infiltration into the pancreas during the inflammation-to-neoplasm transformation, thus decelerated malignancy transformation. Moreover, the anti-tumor effect of Notch signaling inhibitor would be abolished by exogenous IL-17 injection. However, the underlying mechanism needs to be evaluated. In the present study, we firstly plan to study the interaction between Notch signaling and IL-17, and evaluate the anti-tumor effect of combined Notch signaling and IL-17 inhibitions using a mouse pancreatic cancer model with Kras gene mutation. We also plan to the study the molecular crosstalk between Notch signaling and IL-17 using pancreatic cancer cell lines. Finally, we plan to evaluate the diagnostic and prognostic value of inflammation related cytokines for pancreatic cancer using the clinical specimens and data. In conclusion, we aim to uncover the therapeutic effect and molecular mechanisms of combined Notch signaling and IL-17 inhibitions for pancreatic inflammation-to-neoplasm transformation. So there would be more understanding about the progress of pancreatic inflammation-to-neoplasm transformation, thus providing theoretical evidences for new targets and combined therapy for pancreatic cancer treatment.

胰腺癌是一种恶性度高、预后差的消化系统肿瘤。临床上可以观察到从慢性胰腺炎向胰腺癌的转化，提示抑制胰腺炎癌转化过程可能起到抗肿瘤的作用。目前已发现白介素17和Notch信号通路都参与胰腺炎癌转化过程，分别抑制这两者可减缓胰腺癌变进程。本课题组前期研究发现Notch信号阻断剂可抑制胰腺炎癌转化过程中免疫细胞的浸润，并减缓癌变；同时发现外源性白介素17可抵消Notch信号阻断剂的抑癌效果，但相互作用机制尚不清楚。因此本研究拟通过Kras突变胰腺癌小鼠模型评估胰腺炎癌转化过程中Notch信号与白介素17的相互作用，观察联合给药的抗肿瘤效果；利用胰腺癌细胞系研究两者相互作用的分子机理；并利用临床标本和资料探索相关炎症因子在胰腺癌诊断和预后判断中的价值。通过本研究，我们试图揭示联合阻断Notch与白介素17信号对胰腺炎癌转化的抑制作用及其分子机制，为联合用药提供理论依据，并为胰腺癌的治疗提供新靶点。

胰腺癌恶性程度高、早期诊断困难、治疗效果不理想，病死率始终居高不下。胰腺癌的进展过程中存在大量信号通路的异常激活/失活，这些通路的异常状态可由突变的积累导致，也可能受到其他信号通路的调控。同时，慢性胰腺炎是胰腺癌的高危因素之一，多种炎症细胞、细胞因子对肿瘤微环境中的免疫状态及肿瘤的生物学行为均有重要调节作用。本实验希望研究IL-17A信号通路与Notch信号通路在胰腺癌发生、进展中的功能及其相互作用的机制，为丰富“炎癌转化”理论做出贡献，同时为临床中联合使用两通路抑制剂治疗胰腺癌提供理论依据和实验基础。.细胞及分子生物学实验方面，我们通过干预胰腺癌细胞IL-17及Notch信号通路活性，发现两条信号通路对胰腺癌细胞增殖、侵袭、干细胞成球等生物学行为具有促进作用，并结合分子生物学实验获得相关改变的直接证据。生物信息学方面，通过对IL-17及Notch信号通路所调控的差异基因进行GO、Pathway分析，并结合相关数据库信息，挖掘IL-17及Notch可共同调控与细胞增殖、调控细胞周期相关的分子通路，并预测IL-17通过ERK通路促进细胞增殖及其下游可能调控的转录因子。动物实验部分，通过裸鼠皮下成瘤+药物干预实验，印证体内条件下IL-17可对肿瘤的生长的促进作用。同时发现Notch抑制剂对KrasG12D突变小鼠胰腺组织中炎症细胞的浸润数量，及相关炎症因子的分泌水平均有一定抑制作用。临床实验部分，胰腺癌患者外周血中Th17相关细胞因子的含量与其胰腺病变的类型相关，且Th17相关细胞因子具有作为胰腺癌早期诊断的价值。.Notch及IL-17信号通路在胰腺癌的发生、进展过程中受到广泛激活，二者均能上调胰腺癌细胞的恶性程度，且Th17细胞在体内可能通过持续分泌IL-17A因子的方式，上调胰腺腺泡细胞/胰腺癌细胞Notch信号通路多种受体、配体的表达，增加Notch信号通路的活化强度、促进胰腺癌的进展、提高胰腺癌细胞的恶性程度。