Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy.
Department of Paediatrics, Sapienza University of Rome, Rome, Italy.
J Endocrinol Invest. 2019 Feb;42(2):183-197. doi: 10.1007/s40618-018-0900-6. Epub 2018 May 22.
Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in childhood, rarely affects adults, preferring male. RMS expresses the receptor for androgen (AR) and responds to androgen; however, the molecular action of androgens on RMS is unknown.
Herein, testosterone (T) effects were tested in embryonal (ERMS) and alveolar (ARMS) RMS cell lines, by performing luciferase reporter assay, RT-PCR, and western blotting experiments. RNA interference experiments or bicalutamide treatment was performed to assess the specific role of AR. Radiation treatment was delivered to characterise the effects of T treatment on RMS intrinsic radioresistance.
Our study showed that RMS cells respond to sub-physiological levels of T stimulation, finally promoting AR-dependent genomic and non-genomic effects, such as the transcriptional regulation of several oncogenes, the phosphorylation-mediated post-transductional modifications of AR and the activation of ERK, p38 and AKT signal transduction pathway mediators that, by physically complexing or not with AR, participate in regulating its transcriptional activity and the expression of T-targeted genes. T chronic daily treatment, performed as for the hormone circadian rhythm, did not significantly affect RMS cell growth, but improved RMS clonogenic and radioresistant potential and increased AR mRNA both in ERMS and ARMS. AR protein accumulation was evident in ERMS, this further developing an intrinsic T-independent AR activity.
Our results suggest that androgens sustain and improve RMS transformed and radioresistant phenotype, and therefore, their therapeutic application should be avoided in RMS post puberal patients.
横纹肌肉瘤（RMS）是儿童中最常见的软组织肉瘤，很少发生在成年人中，且偏爱男性。RMS 表达雄激素受体（AR）并对雄激素有反应；然而，雄激素对 RMS 的分子作用尚不清楚。
在此，通过荧光素酶报告基因检测、RT-PCR 和 Western blot 实验，检测了睾丸酮（T）对胚胎性（ERMS）和肺泡性（ARMS）RMS 细胞系的影响。进行 RNA 干扰实验或比卡鲁胺处理，以评估 AR 的特定作用。进行放射治疗以评估 T 处理对 RMS 固有放射抵抗性的影响。
我们的研究表明，RMS 细胞对亚生理水平的 T 刺激有反应，最终促进了 AR 依赖性的基因组和非基因组效应，如几个癌基因的转录调控、AR 的磷酸化介导的翻译后修饰以及 ERK、p38 和 AKT 信号转导途径介质的激活，这些介质通过与 AR 物理结合或不结合，参与调节其转录活性和 T 靶向基因的表达。按照激素昼夜节律进行的 T 慢性每日治疗并没有显著影响 RMS 细胞的生长，但改善了 RMS 的集落形成和放射抗性潜力，并增加了 ERMS 和 ARMS 中 AR 的 mRNA。在 ERMS 中明显可见 AR 蛋白的积累，这进一步发展了 AR 的固有 T 非依赖性活性。
我们的研究结果表明，雄激素维持并改善了 RMS 转化和放射抗性表型，因此，应避免在后青春期 RMS 患者中应用雄激素进行治疗。
