Investigate the role of TPD52-AMPK pathway in tumorigenesis and cancer therapy

 描述（由申请人提供）：乳腺癌是最常见的癌症，也是女性癌症死亡的第二大原因。更好地了解乳腺癌的病因将有助于我们更好地预防和治疗这种疾病。LBK 1-AMPK通路是能量代谢的中心调节器，并且该通路的失调与包括乳腺癌在内的癌症有关。间接AMPK激活剂如二甲双胍在乳腺癌预防和治疗中显示出有益效果。然而，除了LKB 1突变之外，这一途径在乳腺癌中如何被错误调节仍不清楚。在本申请中，基于我们广泛的初步数据，我们建议根据其在AMPK调节中的新确定的作用来表征几种因素，进而对乳腺癌和治疗反应进行表征。第一个因子被称为肿瘤抑制蛋白52（TPD 52），我们发现其负调节AMPK。已知TPD 52在HER 2+乳腺癌中过表达，并与HER 2一起促进肿瘤生长。已知AMPK途径也参与抗HER 2应答。此外，我们发现AMPK调节USP 10。USP 10可以增强两个重要肿瘤抑制因子p53和SIRT 6的稳定性，因此我们的发现建立了一条新的AMPK下游途径。据报道，SIRT 6也可以激活AMPK。因此，我们已经确定了一个新的AMPK调节轴，其中TPD 52负调节AMPK，AMPK下游因子UPS 10/SIRT 6形成正反馈环，进一步激活AMPK，所有这些在能量代谢和对二甲双胍诱导的代谢应激的反应中都是重要的。代谢反应是异质性的，因此我们的研究结果可能揭示了潜在的机制。我们的初步数据表明，TPD 52过表达的细胞对二甲双胍以及二甲双胍+HER 2抑制剂组合更敏感。这与先前的研究一致，表明二甲双胍可以抑制细胞增殖并增加HER 2+乳腺癌患者的生存期。基于这些初步发现，我们假设AMPK-USP 10轴有助于AMPK的代谢功能; TPD 52通过负调节AMPK，可以促进能量代谢的失调，并有助于乳腺癌的发展。二甲双胍等药物对TPD 52过表达的患者更有效，可能与HER 2抑制剂联合用于HER 2+癌症。因此，在本申请中，我们建议使用细胞系、乳腺肿瘤样本和乳腺癌患者来源的异种移植物来确定TPD 52如何调节AMPK通路以及AMPK如何通过USP 10的调节来调节SIRT 6和p53，以及这种调节对双胍和抗HER 2治疗的反应的影响。总之，这些研究将帮助我们了解这个新的轴TPD 52-AMPK-USP 10-SIRT 6/p53如何有助于肿瘤发生和治疗反应。

 DESCRIPTION (provided by applicant): Breast cancer is the most common cancer and the second leading cause of cancer death in women. A better understanding of breast cancer etiology would help us to better prevent and treat this disease. The LBK1-AMPK pathway is a central regulator of energy metabolism, and misregulation of this pathway has been implicated in cancers, including breast cancer. Indirect AMPK activators such as metformin have shown beneficial effect in breast cancer prevention and treatment. However, other than LKB1 mutations, how this pathway might be misregulated in breast cancer remains unclear. In this application, based on our extensive Preliminary Data, we propose to characterize several factors based on their newly identified roles in AMPK regulation and in turn, on breast cancer and treatment response. The first factor is called tumor suppressor protein 52 (TPD52) which we found to negatively regulate AMPK. TPD52 is known to overexpress in HER2+ breast cancer and, together with HER2, to promote tumor growth. The AMPK pathway is also known to be involved in anti-HER2 response. Furthermore, we found that AMPK regulates USP10. USP10 can enhance the stability of two important tumor suppressors, p53 and SIRT6, so our finding has established a new downstream pathway to AMPK. It is reported that SIRT6 can also activate AMPK. Therefore, we have identified a new axis of AMPK regulation with TPD52 negatively regulating AMPK with the AMPK downstream factors, UPS10/SIRT6 forming a positive feedback loop, further activating AMPK, all of which would be important in energy metabolism and response to metabolic stress induced by metformin. Metformin response is heterogeneous; therefore our findings could shed light on the underlying mechanisms. Our preliminary data indicated that cells with TPD52 overexpression were more sensitive to metformin as well as combined metformin+HER2 inhibitors. This is consistent with previous studies indicating that metformin can inhibit cell proliferation and increase patient survival in HER2+ breast cancer. Based on these preliminary findings, we hypothesize that the AMPK-USP10 axis contributes to the metabolic function of AMPK; TPD52, by negatively regulating AMPK, can promote misregulation of energy metabolism and contribute to breast cancer development. Drugs like metformin would be more effective in patients with TPD52 overexpression and might be used in combination with HER2 inhibitors in HER2+ cancers. Therefore, in this application, we propose to determine how TPD52 regulates the AMPK pathway and how AMPK might regulate SIRT6 and p53 through the regulation of USP10 as well as the impact of this regulation on response to biguanides and anti-HER2 therapy using cell lines, breast tumor samples, and breast cancer patient derived xenografts. In summary, these studies would help us to understand how this new axis TPD52-AMPK-USP10-SIRT6/p53 contributes to tumorigenesis and treatment response.