Department of Urology, Case Western Reserve University, Cleveland, Ohio.
Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio.
Prostate. 2020 Sep;80(13):1058-1070. doi: 10.1002/pros.24019. Epub 2020 Jul 21.
Most prostate cancers express androgen receptor (AR), and our previous studies have focused on identifying transcription factors that modify AR function. We have shown that nuclear factor I/B (NFIB) regulates AR activity in androgen-dependent prostate cancer cells in vitro. However, the status of NFIB in prostate cancer was unknown.
We immunostained a tissue microarray including normal, hyperplastic, prostatic intraepithelial neoplasia, primary prostatic adenocarcinoma, and castration-resistant prostate cancer tissue samples for NFIB, AR, and synaptophysin, a marker of neuroendocrine differentiation. We interrogated publically available data sets in cBioPortal to correlate NFIB expression and AR and neuroendocrine prostate cancer (NEPCa) activity scores. We analyzed prostate cancer cell lines for NFIB expression via Western blot analysis and used nuclear and cytoplasmic fractionation to assess where NFIB is localized. We performed co-immunoprecipitation studies to determine if NFIB and AR interact.
NFIB increased in the nucleus and cytoplasm of prostate cancer samples versus matched normal controls, independent of Gleason score. Similarly, cytoplasmic AR and synaptophysin increased in primary prostate cancer. We observed strong NFIB staining in primary small cell prostate cancer. The ratio of cytoplasmic-to-nuclear NFIB staining was predictive of earlier biochemical recurrence in prostate cancer, once adjusted for tumor margin status. Cytoplasmic AR was an independent predictor of biochemical recurrence. There was no statistically significant difference between NFIB and synaptophysin expression in primary and castration-resistant prostate cancer, but cytoplasmic AR expression was increased in castration-resistant samples. In primary prostate cancer, nuclear NFIB expression correlated with cytoplasmic NFIB and nuclear AR, while cytoplasmic NFIB correlated with synaptophysin, and nuclear and cytoplasmic AR. In castration-resistant prostate cancer samples, NFIB expression correlated positively with an AR activity score, and negatively with the NEPCa score. In prostate cancer cell lines, NFIB exists in several isoforms. We observed NFIB predominantly in the nuclear fraction of prostate cancer cells with increased cytoplasmic expression seen in castration-resistant cell lines. We observed an interaction between AR and NFIB through co-immunoprecipitation experiments.
We have described the expression pattern of NFIB in primary and castration-resistant prostate cancer and its positive correlation with AR. We have also demonstrated AR interacts with NFIB.
大多数前列腺癌都表达雄激素受体 (AR)，我们之前的研究集中在鉴定改变 AR 功能的转录因子上。我们已经表明，核因子 I/B (NFIB) 在体外调节雄激素依赖性前列腺癌细胞中的 AR 活性。然而，NFIB 在前列腺癌中的状态尚不清楚。
我们对包括正常、增生、前列腺上皮内瘤变、原发性前列腺腺癌和去势抵抗性前列腺癌组织样本的组织微阵列进行 NFIB、AR 和突触素免疫染色，突触素是神经内分泌分化的标志物。我们在 cBioPortal 中查询了公开可用的数据集，以关联 NFIB 表达与 AR 和神经内分泌前列腺癌 (NEPCa) 活性评分。我们通过 Western blot 分析分析了前列腺癌细胞系中的 NFIB 表达，并使用核和细胞质分馏来评估 NFIB 的定位。我们进行了共免疫沉淀研究以确定 NFIB 和 AR 是否相互作用。
与匹配的正常对照相比，NFIB 在前列腺癌样本的核和细胞质中增加，而与 Gleason 评分无关。同样，细胞质 AR 和突触素在原发性前列腺癌中增加。我们观察到原发性小细胞前列腺癌中 NFIB 染色强烈。一旦调整肿瘤边缘状态，细胞质 NFIB 与核 NFIB 染色的比值可预测前列腺癌的早期生化复发。细胞质 AR 是生化复发的独立预测因子。在原发性和去势抵抗性前列腺癌中，NFIB 和突触素的表达之间没有统计学上的显著差异，但在去势抵抗性样本中细胞质 AR 的表达增加。在原发性前列腺癌中，核 NFIB 表达与细胞质 NFIB 和核 AR 相关，而细胞质 NFIB 与突触素和核和细胞质 AR 相关。在去势抵抗性前列腺癌样本中，NFIB 表达与 AR 活性评分呈正相关，与 NEPCa 评分呈负相关。在前列腺癌细胞系中，NFIB 存在几种同工型。我们观察到 NFIB 主要存在于前列腺癌细胞的核部分，在去势抵抗性细胞系中观察到细胞质表达增加。我们通过共免疫沉淀实验观察到 AR 和 NFIB 之间的相互作用。
我们描述了 NFIB 在原发性和去势抵抗性前列腺癌中的表达模式及其与 AR 的正相关性。我们还证明了 AR 与 NFIB 相互作用。
