Autophagy and Pro-metastatic Differentiation

项目摘要 自噬是一种受到严格调控的细胞内降解和循环过程，对细胞内稳态至关重要 以及对各种癌症相关压力的适应。因为自噬促进了 由于已经建立的肿瘤的适应性，人们对靶向自噬以治疗癌症有很大的兴趣。重要的是，反 疟疾药物，如羟氯喹（HCQ），目前正被重新用作自噬抑制剂，在临床上 肿瘤试验然而，抑制自噬也导致自噬货物的异常积累 受体（ACRs），介导靶标的选择性自噬降解的衔接蛋白，以及 作为多域信令集线器。ACR的积累支持致癌进展， 原发性肿瘤生长，并促进自噬缺陷细胞的治疗抗性，但ACRs的作用 在转移过程中的作用还不太清楚。在最近公布的数据中，我们已经证明， 一种称为BRCA1邻居（NBR1）的特异性ACR在肿瘤自噬被抑制时促进转移 细胞在小鼠乳腺癌模型中，遗传自噬抑制通过以下方式促进自发转移： 使播散的肿瘤细胞生长成明显的大转移瘤。此外，在两个主要 和转移部位，遗传自噬抑制导致肿瘤细胞的显著扩增， 侵袭性和促转移性基底上皮分化，包括细胞角蛋白14（CK14）的表达 和转录因子p63。自噬缺陷肿瘤中NBR1的上调是必要的， 足以促进转移生长和促转移分化。基于这些发现，我们 假设自噬抑制促进多种侵袭性肿瘤亚群的出现， NBR1周转受损。在目的1中，我们将确定NBR1促进基底上皮细胞增殖的机制。 癌细胞的分化。在aim2中，我们将评估自噬抑制对肿瘤复发的影响 和瘤内异质性。在目标3中，我们将仔细研究如何在治疗上调节自噬， 通过促进NBR1的更新或隔离，积极或消极地影响转移分化。 总的来说，这个建议将阐明自噬和NBR1控制侵袭性细胞的机制。 乳腺癌的分化程序以及这种调节如何影响复发和治疗反应。

PROJECT SUMMARY Autophagy is a tightly regulated intracellular degradation and recycling process crucial for cellular homeostasis and adaptation to diverse cancer-relevant stresses. Because autophagy promotes the survival and metabolic fitness of established tumors, there is great interest in targeting autophagy to treat cancer. Importantly, anti- malarials, such as hydroxychloroquine (HCQ) are currently being repurposed as autophagy inhibitors in clinical oncology trials. However, inhibiting autophagy also results in aberrant accumulation of autophagy cargo receptors (ACRs), adaptor proteins that mediate the selective autophagic degradation of targets as well as function as multidomain signaling hubs. The accumulation of ACRs supports oncogenic progression, drives primary tumor growth and promotes therapeutic resistance in autophagy-deficient cells, but the role of ACRs during metastasis has been less clear. In recently published data, we have demonstrated that the accumulation of a specific ACR, called neighbor of BRCA1 (NBR1), promotes metastasis when autophagy is inhibited in tumor cells. In mouse mammary cancer models, genetic autophagy inhibition promotes spontaneous metastasis by enabling the outgrowth of disseminated tumor cells into overt macro-metastases. Furthermore, at both primary and metastatic sites, genetic autophagy inhibition leads to the marked expansion of tumor cells exhibiting aggressive and pro-metastatic basal epithelial differentiation, including the expression of cytokeratin 14 (CK14) and the transcription factor p63. The upregulation of NBR1 in autophagy-deficient tumors is both necessary and sufficient to promote metastatic outgrowth and pro-metastatic differentiation. Based on these findings, we hypothesize that autophagy inhibition promotes the emergence of multiple aggressive tumor subpopulations due to impaired NBR1 turnover. In aim 1, we will determine the mechanisms how NBR1 promotes basal epithelial differentiation in carcinoma cells. In aim 2, we will evaluate the effect of autophagy inhibition on tumor recurrence and intratumor heterogeneity. In aim 3, we will scrutinize how therapeutically modulating autophagy, both positively or negatively, impacts metastatic differentiation via promoting the turnover or sequestration of NBR1. Overall, this proposal will elucidate the mechanisms by which autophagy and NBR1 control aggressive differentiation programs in breast cancer and how this regulation impacts recurrence and treatment response.