Peippo Minna, Gardberg Maria, Kronqvist Pauliina, Carpén Olli, Heuser Vanina D
Department of Pathology, Turku University Hospital, University of Turku, Turku, Finland.
Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, Turku, Finland.
J Breast Cancer. 2023 Dec;26(6):525-543. doi: 10.4048/jbc.2023.26.e47. Epub 2023 Nov 17.
Human epidermal growth factor receptor 2 (HER2)-targeted therapies, such as trastuzumab, benefit patients with HER2-positive metastatic breast cancer; however, owing to traditional pathway activation or alternative signaling, resistance persists. Given the crucial role of the formin family in shaping the actin cytoskeleton during cancer progression, these proteins may function downstream of the HER2 signaling pathway. Our aim was to uncover the potential correlations between formins and HER2 expression using a combination of public databases, immunohistochemistry, and functional assays.
Using online databases, we identified a negative prognostic correlation between specific formins mRNA expression in HER2-positive cancers. To validate these findings at the protein level, immunohistochemistry was performed on HER2 subtype breast cancer tumors to establish the links between staining patterns and clinical characteristics. We then knocked down individual or combined formins in MDA-MB-453 and SK-BR-3 cells and investigated their effects on wound healing, transwell migration, and proliferation. Furthermore, we investigated the effects of erb-b2 receptor tyrosine kinase 2 (ERBB2)/HER2 small interfering RNA (siRNA)-mediated knockdown on the PI3K/Akt and MEK/ERK1 pathways as well as on selected formins.
Our results revealed that correlations between , , and mRNA expression and in HER2-subtype breast cancer were associated with worse outcomes. Using immunohistochemistry, we found that high FHOD1 protein expression was linked to higher histological grades and was negatively correlated with estrogen and progesterone receptor positivity. Upon formins knockdown, we observed effects on wound healing and transwell migration, with a minimal impact on proliferation, which was evident through single and combined knockdowns in both cell lines. Notably, siRNA-mediated knockdown of HER2 affected FHOD1 and INF2 expression, along with the phosphorylated Akt/MAPK states.
Our study highlights the roles of FHOD1 and INF2 as downstream effectors of the HER2/Akt and HER2/MAPK pathways, suggesting that they are potential therapeutic targets in HER2-positive breast cancer.
人表皮生长因子受体2（HER2）靶向治疗，如曲妥珠单抗，可使HER2阳性转移性乳腺癌患者获益；然而，由于传统途径激活或替代信号传导，耐药性仍然存在。鉴于formin家族在癌症进展过程中塑造肌动蛋白细胞骨架方面的关键作用，这些蛋白可能在HER2信号通路下游发挥作用。我们的目的是通过结合公共数据库、免疫组织化学和功能分析，揭示formin与HER2表达之间的潜在相关性。
利用在线数据库，我们在HER2阳性癌症中发现特定formin mRNA表达之间存在负性预后相关性。为了在蛋白质水平验证这些发现，对HER2亚型乳腺癌肿瘤进行了免疫组织化学检测，以建立染色模式与临床特征之间的联系。然后，我们在MDA-MB-453和SK-BR-3细胞中敲低单个或组合的formin，并研究它们对伤口愈合、Transwell迁移和增殖的影响。此外，我们研究了erb-b2受体酪氨酸激酶2（ERBB2）/HER2小干扰RNA（siRNA）介导的敲低对PI3K/Akt和MEK/ERK1途径以及选定formin的影响。
我们的结果显示，HER2亚型乳腺癌中 、 和 mRNA表达与 之间的相关性与较差的预后相关。通过免疫组织化学，我们发现高FHOD1蛋白表达与更高的组织学分级相关，并且与雌激素和孕激素受体阳性呈负相关。在敲低formin后，我们观察到对伤口愈合和Transwell迁移有影响，对增殖的影响最小，这在两种细胞系的单次和联合敲低中都很明显。值得注意的是，siRNA介导的HER2敲低影响了FHOD1和INF2表达，以及磷酸化的Akt/MAPK状态。
我们的研究突出了FHOD1和INF2作为HER2/Akt和HER2/MAPK途径下游效应器的作用，表明它们是HER2阳性乳腺癌的潜在治疗靶点。
