Targeting innate immune pathways in breast cancers with chromosomal instability

项目摘要/摘要 虽然在治疗原发性乳腺癌方面已经取得了相当大的进展，但转移性乳腺癌再一次 主要是一个挑战。转移性乳腺癌细胞通常具有染色体不稳定(CIN)，涉及 染色体水平的改变导致基因组拷贝数异常。瞄准目标的一个主要挑战 CIN导致的乳腺癌是由于缺乏已知的靶向性改变。我们最近发现，CIN PRO- 癌细胞中的慢性炎症信号。当染色体错误分离时，它们通常会变得内切- 被包裹在微核中。随后的微核破裂使基因组双链DNA暴露于 胞浆。胞浆DNA激活抗病毒的先天免疫途径，其中最主要的是cGAS刺痛信号- 英。在正常情况下，cGAS-STING激活促进I型干扰素，促进细胞- 中介免疫。刺痛作用于正常的上皮细胞会导致衰老和细胞死亡。我们 然而，已经表明癌细胞对cGAS刺痛的激活具有内在的抵抗力，这是由于它们的 长期接触胞浆DNA。取而代之的是，它们上调了斯汀下游的替代路径，如 作为核因子-κB信号。癌细胞对慢性炎症信号的依赖程度很低。 他站起来了。更重要的是，它们如何颠覆先天免疫信号以避免免疫监视仍然存在 未知。我们正在进行的工作表明，cGAS-STING信号被隔离在远离 主持人。此外，人类乳腺肿瘤上调了ENPP1，这是cGAS-STING信号的负调节因子。 ENPP1通过降解cGAMP来实现免疫逃避，cGAMP是cGAS产生的第二个信使，只有在 细胞外空间。因此，ENPP1阻止宿主刺痛对肿瘤-宿主cGAMP的响应 调职。值得注意的是，对STING的药物抑制抑制了同基因的Melano-Me模型中的转移。 乳腺癌、乳腺癌和结肠癌。我们推测这是因为它对肿瘤细胞的抑制超过了它的保护作用。 在主持人中扮演的角色。在这项工作的基础上，我们将扩大我们对乳房罐头刺抑制的临床前测试- 探讨CER在延缓转移和治疗耐药方面的疗效(目标1)。然后我们将检查 CGAMP是否通过代谢促进免疫抑制微环境的形成 细胞外间隙中的波状分解(目标2)。最后，我们将开发基于cGAS-STING的生物标记 前瞻性收集肿瘤标本。我们将测试cGAS-STING信令和 ENPP1水平可预测新辅助化疗和免疫治疗药物阿替唑单抗的疗效 最近被批准用于治疗转移性乳腺癌(AIM 3)。我们的工作解决了一个临床上没有得到满足的问题 需要通过使用CIN来针对乳腺癌的子集，而对这些乳腺癌的治疗选择有限。如果 它的成功将为首次对刺痛抑制剂进行人体试验提供临床前的理论基础，用于治疗 癌症转移以及预测治疗反应的新型CIN相关生物标记物的开发。

PROJECT SUMMARY/ABSTRACT While considerable progress has been made in treating primary breast cancers, metastatic breast cancers re- main a challenge. Metastatic breast cancer cells typically have chromosomal instability (CIN) that involves chromosome-level alterations leading to genomic copy number abnormalities. A major challenge in targeting breast cancers driven by CIN is the lack of known targetable alterations. We recently found that CIN pro- motes chronic inflammatory signaling in cancer cells. As chromosomes missegregate, they often become en- capsulated in micronuclei. Subsequent micronuclear rupture exposes genomic double-stranded DNA to the cytosol. Cytosolic DNA activates anti-viral innate immune pathways, chief among which is cGAS-STING signal- ing. Under normal circumstances, cGAS-STING activation promotes type I interferon and facilitates cell- mediated immunity. Engagement of STING in normal epithelial cells induces senescence and cell death. We have shown that cancer cells, however, are intrinsically resistant to cGAS-STING activation by virtue of their chronic exposure to cytosolic DNA. Instead, they upregulate alternative pathways downstream of STING, such as NF-κB signaling. The extent to which cancer cells depend on chronic inflammatory signaling is poorly un- derstood. More importantly, how they subvert innate immune signaling to avoid immune surveillance remains unknown. Our ongoing work reveals that cGAS-STING signaling is sequestered in cancer cells away from the host. Furthermore, human breast tumors upregulate ENPP1, a negative regulator of cGAS-STING signaling. ENPP1 enables immune evasion by degrading cGAMP, the second messenger produced by cGAS, only in the extracellular space. As such ENPP1 prevents host STING activation in response to tumor-to-host cGAMP transfer. Strikingly, pharmacologic inhibition of STING suppresses metastasis in syngeneic models of melano- ma, breast, and colon cancers. We postulate this is because its inhibition in tumor cells outweighs its protective role in the host. Building on this work, we will expand our pre-clinical testing of STING inhibition in breast can- cer probing its efficacy in delaying metastasis and therapeutic resistance (Aim 1). We will then examine whether cGAMP contributes toward the formation of an immune suppressive microenvironment through meta- bolic breakdown in the extracellular space (Aim 2). Finally, we will develop cGAS-STING-based biomarkers in prospectively collected tumor specimens. We will test whether the status of cGAS-STING signaling and ENPP1 levels can predict response to neoadjuvant chemotherapy and atezolizumab, an immunotherapeutic recently approved for the treatment of metastatic breast cancer (Aim 3). Our work addresses a clinically unmet need by targeting a subset of breast cancers with CIN and for which there are limited therapeutic options. If successful it will provide pre-clinical rationale for first-in-human testing of STING inhibitors for the treatment of cancer metastasis as well as the development of novel CIN-related biomarkers to predict therapeutic response.