Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, Maryland.
Mol Cancer Ther. 2018 Oct;17(10):2079-2090. doi: 10.1158/1535-7163.MCT-18-0117. Epub 2018 Jul 20.
Clinical management of castration-resistant prostate cancer (CRPC) resulting from androgen deprivation therapy remains challenging. CRPC is driven by aberrant activation of androgen receptor (AR) through mechanisms ranging from its amplification, mutation, post-translational modification, and expression of splice variants (e.g., AR-V7). Herein, we present experimental evidence for therapeutic vulnerability of CRPC to a novel phytochemical, leelamine (LLM), derived from pine tree bark. Exposure of human prostate cancer cell lines LNCaP (an androgen-responsive cell line with mutant AR), C4-2B (an androgen-insensitive variant of LNCaP), and 22Rv1 (a CRPC cell line with expression of AR-Vs), and a murine prostate cancer cell line Myc-CaP to plasma achievable concentrations of LLM resulted in ligand-dependent (LNCaP) and ligand-independent (22Rv1) growth inhibition that was accompanied by downregulation of mRNA and/or protein levels of full-length AR as well as its splice variants, including AR-V7. LLM treatment resulted in apoptosis induction in the absence and presence of R1881. modeling followed by luciferase reporter assay revealed a critical role for noncovalent interaction of LLM with Y739 in AR activity inhibition. Substitution of the amine group with an isothiocyanate functional moiety abolished AR and cell viability inhibition by LLM. Administration of LLM resulted in 22Rv1 xenograft growth suppression that was statistically insignificant but was associated with a significant decrease in Ki-67 expression, mitotic activity, expression of full-length AR and AR-V7 proteins, and secretion of PSA. This study identifies a novel chemical scaffold for the treatment of CRPC. .
雄激素剥夺治疗后去势抵抗性前列腺癌（CRPC）的临床管理仍然具有挑战性。CRPC 是由雄激素受体（AR）通过多种机制异常激活驱动的，包括其扩增、突变、翻译后修饰和剪接变体的表达（例如，AR-V7）。在此，我们提供了实验证据，证明一种新型植物化学物质 leelamine（LLM）可治疗 CRPC，LLM 来源于松树皮。暴露于人前列腺癌细胞系 LNCaP（具有突变 AR 的雄激素反应细胞系）、C4-2B（LNCaP 的雄激素不敏感变体）和 22Rv1（具有 AR-Vs 表达的 CRPC 细胞系）以及一种鼠前列腺癌细胞系 Myc-CaP 于可达到血浆浓度的 LLM 导致配体依赖性（LNCaP）和配体非依赖性（22Rv1）生长抑制，同时下调全长 AR 及其剪接变体（包括 AR-V7）的 mRNA 和/或蛋白水平。在没有和存在 R1881 的情况下，LLM 处理导致细胞凋亡诱导。 后续的荧光素酶报告基因测定表明，LLM 与 AR 活性抑制的 Y739 之间的非共价相互作用起关键作用。用异硫氰酸酯官能团取代胺基可消除 LLM 对 AR 和细胞活力的抑制作用。LLM 的给药导致 22Rv1 异种移植物生长抑制，但统计学上无显著性差异，但与 Ki-67 表达、有丝分裂活性、全长 AR 和 AR-V7 蛋白表达以及 PSA 分泌的显著降低相关。这项研究确定了一种用于治疗 CRPC 的新型化学支架。
