The role of exosome-mediated crosstalk between cancer cells and nerves in pancreatic cancer

胰腺癌（PDAC）是公认的最致命的癌症之一。虽然在PDAC中向继发性器官转移是常见的，但它也表现出癌细胞渗透到神经的高频率，采用另一种转移方式。这种特殊的转移途径被称为神经侵袭（NI）。它已成为PDAC的标志之一，因为它经常与预后不佳有关。在目前的提议中，我们的目的是研究胰腺癌细胞和神经周围微环境之间的外泌体介导的串扰是否对肿瘤进展有影响。通过释放外泌体，癌细胞可以将致癌分子运送到受体细胞和细胞外基质，改变局部和全身肿瘤微环境，支持癌症的发生。然而，癌细胞和神经之间的外泌体介导的串扰及其对胰腺癌NI的影响尚不清楚。因此，本建议的原则将是研究肿瘤来源的外泌体如何重新编程神经微环境以诱导NI。在Aim1.1中，我们将验证雪旺细胞和神经元与来自神经侵袭性胰腺细胞和/或活化的成纤维细胞（胰腺星状细胞）的外泌体预处理将增加胰腺癌细胞在体外和体内的神经侵袭性的假设。为了进一步了解pdac衍生的外泌体如何支持神经入侵，我们将通过在体内靶向不同的途径来破坏外泌体串扰。这也将有助于阐明外泌体功能的损伤是否可能是癌症治疗的潜在靶点。在Aim1.2中，我们想要评估来自高和低ni电位的PDAC细胞的外泌体是否可以决定嗜神经性。我们的目标是鉴定可以增加NI的外泌体相关分子。随后，我们将研究靶向这些特定的外泌体标记是否可以减少神经侵袭。在Aim 2中，我们将研究雪旺细胞来源的外泌体对癌细胞神经侵袭性的相互影响。这是一个最新的新概念，大多数研究只关注肿瘤细胞单向外泌体转移在（神经）微环境中的作用。这些数据可以为外泌体介导的侵袭行为提供新的视角，并将进一步评估肿瘤微环境在胰腺癌肿瘤进展中的作用。此外，我们计划在雪旺细胞来源的外泌体中鉴定ni促进靶点，这些靶点可以靶向抑制受体PDAC细胞的激活和肿瘤促进作用。Aim 1和Aim 2的结果将有助于确定潜在的诊断和预测标志物，我们计划在Aim 3的大型胰腺癌患者队列中进行验证。这些数据将提供一种新的方法来将患者分为不同的风险类别，并提高对复发性PDAC的早期发现的诊断。

Pancreatic cancer (PDAC) is widely recognized as one of the most deadly cancer. While metastasis to secondary organs is common in PDAC, it also exhibits a high frequency of cancer cell penetration into nerves, employing another mode of metastasis. This special route of metastasis has been known as neural invasion (NI). It has become one of the hallmarks of PDAC because it is frequently associated with a dismal prognosis. In the current proposal, we aim to investigate if the exosome-mediated crosstalk between pancreatic cancer cells and the perineural microenvironment have an effect on tumor progression. By the release of exosomes, cancer cells can shuttle oncogenic molecules to recipient cells and the extracellular matrix, altering the local and systemic tumor microenvironment in support of cancer. However, the exosome-mediated crosstalk between cancer cells and nerves and the impact on the NI in pancreatic cancer remains elusive. Thus, the principle of this proposal will be to investigate how tumor-derived exosomes reprogram the nerve microenvironment to induce NI. In Aim1.1, we will test the hypothesis that pre-conditioning of Schwann cells and neurons with exosomes from neural invasive pancreatic cells and/or activated fibroblasts (pancreatic stellate cells) will increase the neuro-invasiveness of pancreatic cancer cells in vitro and in vivo. To further understand how PDAC-derived exosomes support the neural invasion, we will disrupt the exosomal crosstalk by targeting different pathways in vivo. This will help also to elucidate if the impairment of the exosome function might be a potential target in cancer therapy. In Aim1.2, we want to evaluate if exosomes from PDAC cells with high and low NI-potential can determine neurotropism. We aim to identify exosome-associated molecules that can increase NI. Subsequently, we will investigate if targeting those specific exosomal markers can reduce neural invasion. In Aim 2, we will investigate the reciprocal impact of Schwann cell-derived exosomes on neuro-invasiveness of cancer cells. This is a novel concept since up-to-date, the majority of the studies has focused only on the role of the unidirectional exosomal transfer from tumor cells on the (neural) microenvironment. These data can provide a new perspective of the exosome-mediated invasive behaviour and will further assess the role of the tumor microenvironment on tumor progression in pancreatic cancer. Moreover, we plan to identify NI-promoting targets in Schwann cell-derived exosomes that can be targeted to inhibit the activation and tumor-promoting effect in recipient PDAC cells. The results of Aim 1 and Aim 2 will help to identify potential diagnostic and predictive markers, which we plan to validate in a large cohort of patients with pancreatic cancer in Aim 3. These data would provide a novel approach to stratify patients into different risk categories and to improve the diagnosis for the early detection of recurrent PDAC.