Sensitivity to targeted therapy differs between HER2-amplified breast cancer cells harboring kinase and helical domain mutations in PIK3CA.
Sensitivity to targeted therapy differs between HER2-amplified breast cancer cells harboring kinase and helical domain mutations in PIK3CA.
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DOI：
10.1186/s13058-021-01457-0
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发表时间：
2021-08-03
期刊：
影响因子：
--
通讯作者：
Korkola JE
中科院分区：
文献类型：
--
作者：
Garay JP;Smith R;Devlin K;Hollern DP;Liby T;Liu M;Boddapati S;Watson SS;Esch A;Zheng T;Thompson W;Babcock D;Kwon S;Chin K;Heiser L;Gray JW;Korkola JE
HER2扩增乳腺癌是一种临床定义的乳腺癌亚型，有多种可行的靶向治疗方法。对这些靶向治疗的耐药性是一个常见的问题，但耐药发生的机制仍然没有完全确定。已经提出的一种机制是通过突变PI3-激酶途径中的基因。HER2途径的细胞内信号可以通过PI3-激酶发生，编码基因PIK3CA的突变是已知的致癌作用。在 扩增的亚型中，有20%的病例PIK3CA突变与hER2扩增共存。我们使用腺相关病毒介导的基因打靶技术在HER2扩增的乳腺癌细胞中产生了每个PIK3CA热点突变的等基因敲门突变。使用组合药物筛选分析同基因克隆，以确定对HER2靶向治疗的差异反应。Western印迹分析和免疫荧光显示耐受HER2靶向治疗的细胞具有独特的细胞内信号动力学。随后的联合药物筛选被用来探索NeuRegin-1介导的对HER2靶向治疗的耐药性。最后，体外实验的结果被外推到公开可用的数据集。HER2靶向治疗显示，激活域(H1047R)的突变而不是螺旋域(E545K)的突变增加了对拉帕替尼的耐药性。从机制上讲，持续的AKT信号导致了具有激活域突变的细胞对拉帕替尼的耐药性，正如PI3-激酶的胞内产物PIP3染色所证明的那样。这种耐药性可以通过与下游激酶AKT的抑制剂共同处理来克服。此外，PIP3磷酸酶PTEN的敲除也复制了这一结果。我们还发现，神经调节蛋白-1，HER家族受体的配体，对含有热点突变的细胞具有抵抗力，并调节对联合治疗的反应。最后，我们通过对TCGA和METABRIC数据队列的分析，展示了临床证据表明，热点突变具有与治疗耐药相关的不同表达谱。我们的结果显示了独特的细胞内信号差异，这取决于细胞中包含的PIK3CA突变。只有激酶结构域的突变才能完全激活PI3-激酶信号通路，并在HER2抑制的情况下维持下游信号。此外，我们还表明，了解靶向治疗HER2扩增乳腺癌患者的PIK3CA突变状态和NeuRegin-1表达水平具有潜在的临床重要性，这些问题需要进一步的临床前和临床测试。网上版载有补充材料，可在10.1186/s13058-021-01457-0查阅。
HER2-amplified breast cancer is a clinically defined subtype of breast cancer for which there are multiple viable targeted therapies. Resistance to these targeted therapies is a common problem, but the mechanisms by which resistance occurs remain incompletely defined. One mechanism that has been proposed is through mutation of genes in the PI3-kinase pathway. Intracellular signaling from the HER2 pathway can occur through PI3-kinase, and mutations of the encoding gene PIK3CA are known to be oncogenic. Mutations in PIK3CA co-occur with HER2-amplification in ~ 20% of cases within the HER2-amplified subtype. We generated isogenic knockin mutants of each PIK3CA hotspot mutation in HER2-amplified breast cancer cells using adeno-associated virus-mediated gene targeting. Isogenic clones were analyzed using a combinatorial drug screen to determine differential responses to HER2-targeted therapy. Western blot analysis and immunofluorescence uncovered unique intracellular signaling dynamics in cells resistant to HER2-targeted therapy. Subsequent combinatorial drug screens were used to explore neuregulin-1-mediated resistance to HER2-targeted therapy. Finally, results from in vitro experiments were extrapolated to publicly available datasets. Treatment with HER2-targeted therapy reveals that mutations in the kinase domain (H1047R) but not the helical domain (E545K) increase resistance to lapatinib. Mechanistically, sustained AKT signaling drives lapatinib resistance in cells with the kinase domain mutation, as demonstrated by staining for the intracellular product of PI3-kinase, PIP3. This resistance can be overcome by co-treatment with an inhibitor to the downstream kinase AKT. Additionally, knockout of the PIP3 phosphatase, PTEN, phenocopies this result. We also show that neuregulin-1, a ligand for HER-family receptors, confers resistance to cells harboring either hotspot mutation and modulates response to combinatorial therapy. Finally, we show clinical evidence that the hotspot mutations have distinct expression profiles related to therapeutic resistance through analysis of TCGA and METABRIC data cohorts. Our results demonstrate unique intracellular signaling differences depending on which mutation in PIK3CA the cell harbors. Only mutations in the kinase domain fully activate the PI3-kinase signaling pathway and maintain downstream signaling in the presence of HER2 inhibition. Moreover, we show there is potentially clinical importance in understanding both the PIK3CA mutational status and levels of neuregulin-1 expression in patients with HER2-amplified breast cancer treated with targeted therapy and that these problems warrant further pre-clinical and clinical testing. The online version contains supplementary material available at 10.1186/s13058-021-01457-0.
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影响因子：
7.3
作者：
Gao J;Aksoy BA;Dogrusoz U;Dresdner G;Gross B;Sumer SO;Sun Y;Jacobsen A;Sinha R;Larsson E;Cerami E;Sander C;Schultz N
通讯作者：
Schultz N
影响因子：
50.5
作者：
Lesurf, R.;Griffith, O. L.;Mardis, E. R.
通讯作者：
Mardis, E. R.
影响因子：
56.9
作者：
Miled, Nabil;Yan, Ying;Williams, Roger L.
通讯作者：
Williams, Roger L.
影响因子：
28.4
作者：
Borges, Virginia F.;Ferrario, Cristiano;Hamilton, Erika
通讯作者：
Hamilton, Erika
影响因子：
3.6
作者：
Bachman, KE;Argani, P;Park, BH
通讯作者：
Park, BH