INVESTIGATION OF THE VASCULAR RESPONSE IN LYMPH NODE METASTASES

描述(申请人提供)：转移仍然是癌症死亡的主要原因。此外，在人类实体癌中，淋巴结状况是影响患者预后的最重要的指标。淋巴结中癌细胞的存在与5年无瘤存活率的绝对降低有关。因此，在乳腺癌和黑色素瘤等癌症中，切除前哨淋巴结已成为治疗患者的标准方法。然而，在同时接受辅助治疗的有淋巴结受累的患者中，无病生存率得到了改善。这表明肿瘤细胞可能潜伏在远端的结节和器官中。因此，挑战是如何治疗已经扩散到淋巴结或远处器官的癌细胞，以防止它们的生长，最好是将它们从体内消除。一类著名的辅助治疗是抗血管生成抑制药。尽管血管生成对原发肿瘤的生长和建立至关重要，但尚不清楚这一过程对已转移的癌细胞有多重要。通过建立改良的转移模型，本项目旨在研究淋巴转移中血管生成的反应。使用抗血管生成疗法的临床试验并没有像预测的那样顺利。这一结果的一个原因可能是这种疗法是针对在其自然微环境中生长的原发肿瘤而开发的。然而，很明显，肿瘤细胞生长的局部微环境对肿瘤细胞的生长速度、代谢、血管形成以及最终对治疗干预的反应有很大影响。这项建议的目标1的初步结果表明，一旦癌细胞到达，在原发肿瘤部位观察到的经典萌芽血管生成对于淋巴中的肿瘤生长不是必需的。我假设，在早期和晚期转移的淋巴结中，调节肿瘤生长的分子和细胞机制与新血管的形成无关，与在原发肿瘤中看到的相反。在目标1中，我将使用一组新的小鼠模型来测试并在体内重现这些观察结果。有趣的是，在淋巴结转移的肿块内，CD31染色的密度明显低于非肿瘤区。而这是一个正态分布 在转移性病变的毛细血管中，与“正常”的淋巴结区相比，明显缺乏高内皮微静脉。该提案的目标2中的初步结果表明，淋巴血管的重塑导致对癌细胞的免疫反应受到抑制。我推测，由于肿瘤细胞的机械应力或肿瘤细胞诱导的血管去分化程序，高内皮微静脉失去了运输淋巴细胞的能力，最终导致免疫监视的丧失。在目标2中，我将研究这一机制，并尝试进行治疗干预，以增强对肿瘤细胞的免疫访问。总而言之，这些研究将有助于了解淋巴结转移的进展，并可能对一般的转移生物学产生影响。了解肿瘤在淋巴结等转移部位的生长和存活机制，对于合理设计和使用抗血管生成佐剂等治疗药物至关重要。

DESCRIPTION (provided by applicant): Metastasis remains the principal cause of cancer mortality. Furthermore, lymph node status is the most significant prognostic indicator for patient outcome in human solid cancer. The presence of cancer cells in the lymph node is associated with an absolute reduction in the 5-year rate of disease-free survival. Therefore, in cancers such as breast and melanoma, removal of the sentinel lymph node has become a standard approach to treat patients. However, in patients with lymph node involvement who also received adjuvant therapy, disease-free survival was improved. This suggests that tumor cells may take undetected residence in distal nodes and organs. Thus, the challenge is how to treat cancer cells that have spread to lymph nodes or distant organs in order to prevent their growth and ideally eradicate them from the body. A well-known class of adjuvant therapy is anti-angiogenesis inhibitors. Although angiogenesis is critical for growth and establishment of primary tumors, it is unknown how significant this process is for cancer cells that have metastasized. Through establishment of improved metastasis models, this project aims to investigate the angiogenic response in lymph node metastases. Clinical trials using anti-angiogenesis therapy have not fared as well as predicted. One reason for this outcome may be that this therapy was developed against the primary tumor growing in its native microenvironment. However, it is clear that the local microenvironment in which tumor cells grow greatly affects the growth rate, metabolism, vascularization and ultimately response to therapeutic intervention. Preliminary results in Aim 1 of this proposal suggest that the classical sprouting angiogenesis observed in the primary tumor site is not necessary for tumor growth in the lymph node, once cancer cells arrive. I hypothesize that the molecular and cellular mechanisms regulating tumor growth in early and late metastatic lymph nodes are independent of the formation of new blood vessels, contrary to what is seen in the primary tumor. In Aim 1, I will use a combination of novel mouse models to test and reproduce these observations in vivo. Interestingly, within the metastatic tumor mass in the lymph nodes, the density of CD31 staining is significantly decreased with respect to the non-tumor area. While there is a normal distribution of blood capillaries in the metastatic lesions, there is a noticeable absence of high endothelial venules compared to the "normal" lymph node regions. Preliminary results in Aim 2 of the proposal suggest that remodeling of the lymph node vasculature leads to an inhibition of the immune response against cancer cells. I hypothesize that due to mechanical stress by tumor cells or a vascular dedifferentiation program induced by tumor cells, high endothelial venules lose the capacity to for lymphocyte trafficking and ultimately leads to loss of immune surveillance. In Aim 2, I will investigate this mechanism and attempt to therapeutically intervene in order to enhance immune access to tumor cells. Collectively, these studies will contribute to understanding the progression of metastases in the lymph node, and may have implications for metastasis biology in general. Understanding mechanisms of cancer growth and survival in metastatic sites such as the lymph node is critical for the rational design and use of therapeutics, such as anti-angiogenesis adjuvants.