Breast cancers (BCa) with ERBB2 amplification show rapid tumor growth, increased disease progression, and lower survival rate. Deregulated intracellular trafficking and extracellular vesicle (EVs) release are mechanisms that support cancer progression and resistance to treatments. Neratinib (NE) is a Food and Drug Administration–approved pan-ERBB inhibitor employed for the treatment of ERBB2⁺ BCa that blocks signaling and causes survival inhibition. However, the effects of NE on ERBB2 internalization, its trafficking to multivesicular bodies (MVBs), and the release of EVs that originate from these organelles remain poorly studied. By confocal and electron microscopy, we observed that low nanomolar doses of NE induced a modest ERBB2 internalization along with an increase of clathrin-mediated endocytosis and of the CD63+ MVB compartment in SKBR-3 cells. Furthermore, we showed in the culture supernatant two distinct EV subsets, based on their size and ERBB2 positivity: small (30–100 nm) ERBB2⁻ EVs and large (>100 nm) ERBB2⁺ EVs. In particular, we found that NE increased the overall release of EVs, which displayed a reduced ERBB2 positivity compared with controls. Taken together, these results provide novel insight into the effects of NE on ERBB2⁺ BCa cells that may lead to a reduction of ERBB2 potentially transferred to distant target cells by EVs:

具有 ERBB2 扩增的乳腺癌 (BCa) 显示出快速的肿瘤生长、增加的疾病进展和较低的存活率。细胞内运输和细胞外囊泡 (EV) 释放的失调是支持癌症进展和治疗耐药性的机制。来那替尼 (NE) 是食品和药物管理局批准的泛 ERBB 抑制剂，用于治疗 ERBB2 ⁺BCa 阻断信号传导并导致生存抑制。然而，NE 对 ERBB2 内化的影响、其向多泡体 (MVB) 的运输以及源自这些细胞器的 EV 的释放仍缺乏研究。通过共聚焦和电子显微镜，我们观察到低纳摩尔剂量的 NE 诱导适度的 ERBB2 内化以及网格蛋白介导的内吞作用和 SKBR-3 细胞中 CD63+ MVB 区室的增加。此外，我们在培养上清液中显示了两个不同的 EV 子集，基于它们的大小和 ERBB2 阳性：小 (30-100 nm) ERBB2 ^- EV 和大 (>100 nm) ERBB2 ⁺电动汽车。特别是，我们发现 NE 增加了 EV 的整体释放，与对照相比，其显示出降低的 ERBB2 阳性。综上所述，这些结果提供了对 NE 对 ERBB2 ⁺ BCa 细胞的影响的新见解，这些影响可能导致 ERBB2 可能被 EV 转移到远处靶细胞的减少：