生长抑制因子ING4逆转乳腺癌抗HER2耐药的作用及其机制

The de novo and acquired resistance of anti-HER2 targeted therapy is currently one of major obstacles in HER2+ breast cancer treatment. Inhibitor of growth 4 (ING4) was aberrantly expressed in HER2+ breast cancer, which may be involed in tumorigenesis and development. The anti-HER2 drug resistance is associated with breast cancer stem cells (CSC) and resistance-related transcription factors. It has been reported that NF-κB is a vital transcription factor for breast CSC expansion/maintenance and anti-HER2 drug resistance. It has also been demonstrated that ING4 exhibits unique suppressive activities for NF-κB. Our preliminary data have shown that ING4 inhibits the formation of HER2+ breast cancer stem cells and the secretion of anti-HER2 resistance-associated cytokines. We thus hypothesized that ING4 aberration would result in activation of NF-κB and consequently affect breast CSC in HER2+ breast cancer. Furthermore, NF-κB-mediated inflammatory loop would largely contribute to anti-HER2 de novo and acquired resistance. In the present study, we established HER2+ breast cancer cell model with de novo resistance or de novo sensitivity (that will develop acquired resistance) to anti-HER2 and investigated the effect of ING4 on anti-HER2 resistance and its underlying molecular mechanism in in vitro and in vivo NOD/SCID mouse model. In addition, we explored the clinical correlation of ING4 and HER2+ breast CSC, anti-HER2 therapy efficacy and patient’s prognosis. This project will provide the valuable experimental basis for overcoming anti-HER2 resistance in HER2+ breast cancer patients.

抗HER2靶向药物的原发和继发耐药是目前HER2+乳腺癌治疗的主要障碍。生长抑制因子ING4在HER2+乳腺癌中异常表达，可能参与疾病的发生和发展。抗HER2耐药的产生与乳腺癌干细胞和相关转录因子有关。NF-κB是调控乳腺癌干细胞和抗HER2耐药的关键转录因子，而ING4对NF-κB有独特的抑制作用。我们预实验发现ING4对HER2+乳腺癌干细胞和抗HER2耐药相关细胞因子有抑制作用。因而推测HER2+乳腺癌ING4异常引起的NF-κB激活可能影响乳腺癌干细胞和介导炎症循环，从而诱发抗HER2原发和继发耐药。本项目将建立HER2+乳腺癌抗HER2原发和继发耐药细胞模型，通过体外和动物体内实验探索ING4在抗HER2耐药产生中的作用及其分子机制，并循证HER2+乳腺癌ING4异常与乳腺癌干细胞、抗HER2疗效和患者预后的相关性，为HER2+乳腺癌患者克服抗HER2耐药提供有价值的实验依据。

抗HER2靶向药物的原发、继发耐药是HER2+乳腺癌治疗的主要障碍。生长抑制因子ING4在HER2+乳腺癌中异常表达，其可能参与了疾病的发生和发展。抗HER2耐药与乳腺癌干细胞和相关转录因子有关。NF-κB是调控乳腺癌干细胞和抗HER2耐药的关键转录因子，而ING4对NF-κB具有独特的抑制作用。因此我们推测：HER2+乳腺癌中ING4下调引起的NF-κB异常激活可能促进HER2+乳腺癌干细胞干性和介导炎症循环，从而诱发抗HER2原发、继发耐药。然而，ING4在HER2+乳腺癌中的作用及其与抗HER2疗效、耐药的关系目前尚不清楚。本项目建立ING4过表达的抗HER2原发、继发耐药的HER2+乳腺癌细胞株，采用CCK-8、平板克隆形成、Transwell迁移/侵袭、微球、CD44/CD24染色、Western blot、RT-qPCR等实验，在体外和NOD/SCID小鼠体内探索了ING4对抗HER2药物赫赛汀敏感、耐药HER2+乳腺癌细胞的作用和在赫赛汀耐药中的作用及其机制。结果显示，ING4能抑制赫赛汀敏感、耐药HER2+乳腺癌细胞的增殖/生长、迁移、侵袭、转移及HER2+乳腺癌干细胞的干性维持。ING4能逆转HER2+乳腺癌的赫赛汀原发耐药和延缓、抑制HER2+乳腺癌的赫赛汀继发耐药。ING4能抑制赫赛汀治疗介导的赫赛汀原发耐药HER2+乳腺癌干细胞的扩增和赫赛汀继发耐药HER2+乳腺癌干细胞的产生、扩增。ING4能通过抑制NF-κB-IL-6/IL-8炎症循环抑制miR-21介导PTEN的灭活，进而抑制HER2+乳腺癌的赫赛汀继发耐药。ING4抑制NF-κB-IL-6/IL-8炎症循环引起的赫赛汀耐药HER2+乳腺癌干细胞的抑制可能是ING4逆转、抑制HER2+乳腺癌赫赛汀耐药的重要分子机制。本研究为HER2+乳腺癌抗HER2的耐药机制提供了新视角。