Sible Emily, Weitsman Gregory, Amouyal Salome, Roblot Guillaume, Marotel Marie, Pescarmona Rémi, Bendriss-Vermare Nathalie, Gillett Cheryl, Ceesay Amie, Gazeu Alexia, Michallet Marie Cecile, Caux Christophe, Cosset Francois-Loic, Al Alem Umaima, Ng Tony, Hasan Uzma Ayesha
Centre International de recherche en Infectiologie, CIRI, Inserm, U1111, Lyon, France.
King's College London, London, UK.
J Innate Immun. 2025;17(1):354-368. doi: 10.1159/000545527. Epub 2025 Jun 23.
Toll-like receptor 9 (TLR9) is primarily expressed in human dendritic and B cells and recognizes double-stranded DNA motifs from pathogens to initiate an inflammatory response. Recent studies have revealed TLR9s' involvement beyond its conventional role in the immune response, notably during the tumorigenesis of various cancers such as head and neck, cervical, and ovarian cancers.
In this study patient biopsies of breast cancer tumors and normal breast epithelium were analyzed by immunohistochemistry to examine TLR9 expression. The study also investigated downregulation in transformed breast cancer cell lines compared to untransformed breast epithelial cells by analyzing gene or protein expression, including TLR9, IL-6, CCL2, CXCL1, and GM-CSF. MDA-MB-361 cells were engineered to express exogenous TLR9, and the effects on colony growth and senescence were assessed using colony formation assays, senescence staining, cytokine analysis, and flow cytometry.
TLR9 levels in breast cancer tumors were significantly reduced compared to normal breast tissue epithelium. This downregulation was also observed in several transformed breast cancer cell lines compared to untransformed breast epithelial cell lines. Furthermore, MDA-MB-361 breast cancer cells expressing exogenous TLR9 exhibited reduced colony growth and an increase in the senescence marker IL-6, pro-inflammatory cytokine CCL2, CXCL1 chemokine; and growth factor GM-CSF.
These findings support TLR9's regulatory role in mitigating breast cancer and highlight its critical connection between the innate immunity and tumor cell growth.
Toll样受体9（TLR9）主要在人类树突状细胞和B细胞中表达，识别病原体的双链DNA基序以引发炎症反应。最近的研究表明，TLR9的作用超出了其在免疫反应中的传统作用，特别是在头颈部、宫颈癌和卵巢癌等各种癌症的肿瘤发生过程中。
在本研究中，通过免疫组织化学分析乳腺癌肿瘤和正常乳腺上皮的患者活检组织，以检测TLR9的表达。该研究还通过分析基因或蛋白质表达，包括TLR9、IL-6、CCL2、CXCL1和GM-CSF，研究了与未转化的乳腺上皮细胞相比，转化的乳腺癌细胞系中的下调情况。对MDA-MB-361细胞进行工程改造以表达外源性TLR9，并使用集落形成试验、衰老染色、细胞因子分析和流式细胞术评估对集落生长和衰老的影响。
与正常乳腺组织上皮相比，乳腺癌肿瘤中的TLR9水平显著降低。与未转化的乳腺上皮细胞系相比，在几种转化的乳腺癌细胞系中也观察到这种下调。此外，表达外源性TLR9的MDA-MB-361乳腺癌细胞表现出集落生长减少，衰老标志物IL-6、促炎细胞因子CCL2、CXCL1趋化因子和生长因子GM-CSF增加。
这些发现支持TLR9在减轻乳腺癌中的调节作用，并突出了其在先天免疫和肿瘤细胞生长之间的关键联系。
