Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
Breast Cancer Res Treat. 2012 Apr;132(2):411-9. doi: 10.1007/s10549-011-1590-3. Epub 2011 May 24.
Toll-like receptor 9 (TLR9) is a cellular DNA-receptor, which is widely expressed in cancer. Synthetic TLR9-ligands induce cancer cell invasion in vitro, but the role of TLR9 in cancer pathophysiology remains unclear. Increased TLR9 expression has been, however, detected in estrogen receptor negative (ER-) breast cancers. In this study, we investigated the effects of ERα expression and sex steroid hormones on TLR9 expression in human ER+ (MCF-7, T47-D) and ER- (MDA-MB-231) breast cancer cell lines in vitro. We also studied TLR9 mRNA expression in archival breast cancer specimens (n = 12) with qRT-PCR, using primer sets that detect only the TLR9A isoform or the isoforms A and B (TLR9A/B). The TLR9 mRNA expression was detected in 10/12 specimens with both primer sets, and in 1/12 with only the TLR9A or the TLR9A/B primer sets. The basal TLR9 mRNA expression levels were significantly lower in the ER+ cell lines as compared with the ER- MDA-MB-231 cells. The transfection of ERα cDNA into MDA-MB-231 cells also resulted in down-regulation of TLR9 expression. While sex steroids had no effect on TLR9 expression in MCF-7 cells, testosterone (10(-8) M) induced TLR9 expression in MDA-MB-231 and T47-D cells. Although bicalutamide blocked this testosterone effect in MDA-MB-231 cells, in T47-D cells bicalutamide increased TLR9 expression and only partially blocked the testosterone effects. Estradiol (10(-8) M) induced TLR9 expression in T47-D cells. The invasive effects of synthetic TLR9-ligands were augmented by testosterone in vitro. This effect was lost in TLR9 siRNA MDA-MB-231 cells and also decreased by over-expression of ERα, which also inhibited NF-κB activation by TLR9-ligands. In conclusion, expression of TLR9 isoforms A and B can be detected in clinical breast cancer specimens. The ERα and sex steroid hormones regulate TLR9 expression and invasive effects in the breast cancer cells. Also, the commonly used hormonal cancer therapy bicalutamide affects TLR9 expression.
Toll 样受体 9（TLR9）是一种细胞 DNA 受体，广泛表达于癌症中。合成 TLR9 配体在体外诱导癌细胞侵袭，但 TLR9 在癌症发病机制中的作用尚不清楚。然而，在雌激素受体阴性（ER-）乳腺癌中已检测到 TLR9 表达增加。在这项研究中，我们研究了 ERα 表达和性激素对体外人 ER+（MCF-7、T47-D）和 ER-（MDA-MB-231）乳腺癌细胞系中 TLR9 表达的影响。我们还使用仅检测 TLR9A 同工型或同工型 A 和 B（TLR9A/B）的引物对，通过 qRT-PCR 研究了存档乳腺癌标本（n=12）中 TLR9 mRNA 的表达。使用两种引物对均检测到 10/12 个标本中的 TLR9 mRNA 表达，而仅使用 TLR9A 或 TLR9A/B 引物对检测到 1/12 个标本中的 TLR9 mRNA 表达。与 ER- MDA-MB-231 细胞相比，TLR9 mRNA 的基础表达水平在 ER+ 细胞系中明显较低。将 ERα cDNA 转染 MDA-MB-231 细胞也导致 TLR9 表达下调。虽然性激素对 MCF-7 细胞中的 TLR9 表达没有影响，但睾酮（10(-8) M）诱导 MDA-MB-231 和 T47-D 细胞中的 TLR9 表达。虽然比卡鲁胺阻断了 MDA-MB-231 细胞中的这种睾酮作用，但在 T47-D 细胞中，比卡鲁胺增加了 TLR9 的表达，并部分阻断了睾酮的作用。雌二醇（10(-8) M）诱导 T47-D 细胞中的 TLR9 表达。体外合成 TLR9 配体的侵袭作用被睾酮增强。这种作用在 TLR9 siRNA MDA-MB-231 细胞中丢失，并且在 ERα 的过表达下也降低，ERα 也抑制了 TLR9 配体的 NF-κB 激活。总之，在临床乳腺癌标本中可以检测到 TLR9 同工型 A 和 B 的表达。ERα 和性激素调节乳腺癌细胞中的 TLR9 表达和侵袭作用。此外，常用的激素癌症治疗药物比卡鲁胺也会影响 TLR9 的表达。
