Up-Regulation of LAT1 during Antiandrogen Therapy Contributes to Progression in Prostate Cancer Cells
Up-Regulation of LAT1 during Antiandrogen Therapy Contributes to Progression in Prostate Cancer Cells
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DOI：
10.1016/j.juro.2015.11.071
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发表时间：
2016-05-01
影响因子：
6.6
通讯作者：
Ichikawa, Tomohiko
中科院分区：
文献类型：
--
作者：
Xu, Minhui;Sakamoto, Shinichi;Ichikawa, Tomohiko
目的：癌细胞需要大量的氨基酸才能生存。LAT 1（L型氨基酸转运蛋白1）转运必需氨基酸，包括亮氨酸，其触发下游mTOR（雷帕霉素的哺乳动物靶蛋白）途径。我们研究了雄激素受体和LAT 1之间的关联，以及LAT 1的表达和去势resistance.Materials和方法：Western blot和实时聚合酶链反应，研究蛋白质和mRNA的表达。siRNA用于敲低靶基因。共92例接受雄激素剥夺治疗的患者的前列腺活检标本用于免疫组化分析。结果：LAT 1在激素抵抗的前列腺癌细胞系中呈高表达。在LNCaP和C4-2细胞中敲低LAT 1显著抑制细胞增殖、迁移和侵袭。雄激素受体siRNA或通过比卡鲁胺（10 mM）或MDV 3100（10 mM）阻断雄激素受体显著增加LAT 1表达（p < 0.01）。用二氢睾酮（0.1至10 nM）处理以剂量依赖性方式降低了LAT 1表达（p < 0.01）。与雄激素受体或LAT 1单独抑制相比，比卡鲁胺/MDV 3100加siLAT 1协同抑制前列腺癌细胞增殖（p < 0.01）。在接受雄激素剥夺治疗的患者中，LAT 1高表达与前列腺特异性抗原无复发生存期显著缩短相关（p < 0.0001）。LAT 1的表达是一个独立的预测去势抵抗的多变量分析（HR 3.56，p = 0.0133）。结论：目前的数据可能表明一种新的机制，通过激活氨基酸转运蛋白LAT 1获得去势抵抗。
Purpose: Cancer cells require massive amounts of amino acids for survival. LAT1 (L-type amino acid transporter 1) transports essential amino acids, including leucine, which trigger the downstream mTOR (mammalian target of rapamycin) pathway. We examined the association between androgen receptor and LAT1, and the association between LAT1 expression and the acquisition of castration resistance.Materials and Methods: Western blot and real-time polymerase chain reaction were performed to study protein and mRNA expression. siRNA was used to knock down target genes. A total of 92 prostate biopsy specimens of patients who underwent androgen deprivation therapy were used for immunohistochemical analyses. Cox hazard proportional models and the Kaplan-Meier method were used for statistical analyses.Results: LAT1 was highly expressed in hormone resistant prostate cancer cell lines. Knockdown of LAT1 in LNCaP and C4-2 cells significantly suppressed cell proliferation, migration and invasion. Androgen receptor siRNA or androgen receptor blocking through bicalutamide (10 mM) or MDV3100 (10 mM) significantly increased LAT1 expression (p < 0.01). Treatment with dihydrotestosterone (0.1 to 10 nM) reduced LAT1 expression in a dose dependent manner (p < 0.01). Bicalutamide/MDV3100 plus siLAT1 synergistically suppressed prostate cancer cell proliferation compared to single inhibition by androgen receptor or LAT1 (p < 0.01). High LAT1 expression correlated with significantly shorter prostate specific antigen recurrence-free survival in patients receiving androgen deprivation therapy (p < 0.0001). LAT1 expression was an independent predictor of castration resistance on multivariate analysis (HR 3.56, p = 0.0133).Conclusions: The current data may indicate a novel mechanism to acquire castration resistance through activation of the amino acid transporter LAT1.