DUSP9-mediated reduction of pERK1/2 supports cancer stem cell-like traits and promotes triple negative breast cancer.
DUSP9-mediated reduction of pERK1/2 supports cancer stem cell-like traits and promotes triple negative breast cancer.
复制标题
DOI：
--
复制
发表时间：
2020-10
影响因子：
5.3
通讯作者：
Thalia Jimenez;Albert Barrios;A. Tucker;Javier Collazo;Nataly Arias;S. Fazel;Melanie Baker;M. Halim;T. Huynh;R. Singh;S. Pervin
中科院分区：
文献类型：
--
作者：
Thalia Jimenez;Albert Barrios;A. Tucker;Javier Collazo;Nataly Arias;S. Fazel;Melanie Baker;M. Halim;T. Huynh;R. Singh;S. Pervin
乳腺癌仍然是一种复杂的疾病，导致妇女死亡率很高。表达醛脱氢酶1 （ALDH1）和SOX2/OCT4的癌症干细胞（CSC）样细胞亚群与特定亚型乳腺癌的侵袭性生物学有关。针对这些人群治疗乳腺肿瘤仍然具有挑战性。我们通过实时荧光定量PCR （qRT-PCR）、免疫印迹分析和免疫组织化学检测了三种研究较少的三阴性（TN）乳腺癌细胞（MDA-MB-468、HCC70和HCC1806）和HMLEHRASV12的异种移植物干细胞（SC）特异性蛋白、增殖途径和双特异性磷酸酶（DUSPs）。我们发现，在生长的各个阶段，pERK1/2在TN异种移植物中仍然被抑制，而pp38 MAPK和pAKT的水平上调。我们发现DUSP参与了pERK1/2的抑制，而pERK1/2与MEK1/2无关。我们使用HMLEHRASV12异种移植物作为阳性对照的体外试验证实，磷酸酶活性的增加特异性地影响了pERK1/2，但不影响pp38MAPK或pJNK的水平。DUSPs家族成员在TN异种移植物中显示DUSP9表达增加。异种移植物中DUSP9表达的增加与sc特异性蛋白ALDH1和SOX2/OCT4的上调一致相关。HRAS驱动的HMLEHRASV12异种移植物以及来自TN乳腺癌细胞的乳腺球显示pERK1/2与DUSP9和CSC性状的表达增加呈反比关系。此外，MEK1/2抑制剂PD 98059在体外处理可降低pERK1/2水平，增加DUSP9和sc特异性蛋白。通过荧光活化细胞分选（FACS）去除SOX2/OCT4亚群，以及药理学和遗传学上降低DUSP9水平，会影响ALDH1和SOX2/OCT4的表达，并降低体外乳腺细胞生长和体内肿瘤生长。总的来说，我们的数据支持DUSP9促进可能影响TN乳腺肿瘤生长的干细胞样细胞的可能性。结论：我们的研究表明，MEK1/2独立的pERK1/2水平降低的TN乳腺癌亚群对MEK1/2抑制剂的反应较小，从而质疑其治疗效果。我们的研究还表明，上下文依赖的dusp9介导的pERK1/2水平降低可能影响TN乳腺肿瘤的干细胞样性状。因此，靶向DUSP9可能是改善基底样乳腺癌亚群临床结果的一个有吸引力的靶点。
Breast cancer remains a complex disease resulting in high mortality in women. A subset of cancer stem cell (CSC)-like cells expressing aldehyde dehydrogenase 1 (ALDH1) and SOX2/OCT4 are implicated in aggressive biology of specific subtypes of breast cancer. Targeting these populations in breast tumors remain challenging. We examined xenografts from three poorly studied triple negative (TN) breast cancer cells (MDA-MB-468, HCC70 and HCC1806) as well as HMLEHRASV12 for stem cell (SC)-specific proteins, proliferation pathways and dual-specific phosphatases (DUSPs) by quantitative real-time PCR (qRT-PCR), immunoblot analysis and immunohistochemistry. We found that pERK1/2 remained suppressed in TN xenografts examined at various stages of growth, while the levels of pp38 MAPK and pAKT was upregulated. We found that DUSP was involved in the suppression of pERK1/2, which was MEK1/2 independent. Our in vitro assays, using HMLEHRASV12 xenografts as a positive control, confirmed increased phosphatase activity that specifically influenced pERK1/2 but not pp38MAPK or pJNK levels. Family members of DUSPs examined, showed increase in DUSP9 expression in TN xenografts. Increased DUSP9 expression in xenografts was consistently associated with upregulation of SC-specific proteins, ALDH1 and SOX2/OCT4. HRAS driven HMLEHRASV12 xenografts as well as mammospheres from TN breast cancer cells showed inverse relationship between pERK1/2 and increased expression of DUSP9 and CSC traits. In addition, treatment in vitro, with MEK1/2 inhibitor, PD 98059, reduced pERK1/2 levels and increased DUSP9 and SC-specific proteins. Depletion of subsets of SOX2/OCT4 by fluorescence-activated cell sorting (FACS), as well as pharmacological and genetic reduction of DUSP9 levels influenced ALDH1 and SOX2/OCT4 expression and reduced mammosphere growth in vitro as well as tumor growth in vivo. Collectively our data support the possibility that DUSP9 contributed to stem cell-like cells that could influence TN breast tumor growth. Conclusion: Our study shows that subsets of TN breast cancers with MEK1/2 independent reduced pERK1/2 levels will respond less to MEK1/2 inhibitors, thereby questioning their therapeutic efficacy. Our study also demonstrates context-dependent DUSP9-mediated reduced pERK1/2 levels could influence stem cell-like traits in TN breast tumors. Therefore, targeting DUSP9 could be an attractive target for improved clinical outcome in a subset of basal-like breast cancers.