Shankar Sharmila, Ganapathy Suthakar, Srivastava Rakesh K
Department of Biochemistry, University of Texas Health Science Center at Tyler, Tyler, Texas 75708-3154, USA.
Clin Cancer Res. 2008 Nov 1;14(21):6855-66. doi: 10.1158/1078-0432.CCR-08-0903.
The purpose of this study was to examine the molecular mechanisms by which sulforaphane enhances the therapeutic potential of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in prostate cancer.
Cell viability and apoptosis assays were done by XTT and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, respectively. Tumor-bearing mice were treated with vehicle, sulforaphane, TRAIL, and sulforaphane plus TRAIL. Markers of apoptosis, angiogenesis, and metastasis were measured by immunohistochemistry.
Sulforaphane enhanced the therapeutic potential of TRAIL in PC-3 cells and sensitized TRAIL-resistant LNCaP cells. Sulforaphane-induced apoptosis in PC-3 cells correlated with the generation of intracellular reactive oxygen species (ROS), collapse of mitochondrial membrane potential, activation of caspase-3 and caspase-9, and up-regulation of DR4 and DR5. Sulforaphane induced the expression of Bax, Bak, Bim, and Noxa and inhibited the expression of Bcl-2, Bcl-X(L), and Mcl-1. The quenching of ROS generation with antioxidant N-acetyl-L-cysteine conferred significant protection against sulforaphane-induced ROS generation, mitochondrial membrane potential disruption, caspase-3 activation, and apoptosis. Sulforaphane inhibited growth of orthotopically implanted PC-3 tumors by inducing apoptosis and inhibiting proliferation and also enhanced the antitumor activity of TRAIL. Sulforaphane up-regulated the expressions of TRAIL-R1/DR4, TRAIL-R2/DR5, Bax and Bak and inhibited the activation of nuclear factor-kappaB P13K/AKT and MEK/ERK pathways in tumor tissues. The combination of sulforaphane and TRAIL was more effective in inhibiting markers of angiogenesis and metastasis and activating FOXO3a transcription factor than single agent alone.
The ability of sulforaphane to inhibit tumor growth, metastasis, and angiogenesis and to enhance the therapeutic potential of TRAIL suggests that sulforaphane alone or in combination with TRAIL can be used for the management of prostate cancer.
本研究旨在探讨萝卜硫素增强肿瘤坏死因子相关凋亡诱导配体（TRAIL）对前列腺癌治疗潜力的分子机制。
分别采用XTT法和末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法进行细胞活力和凋亡检测。对荷瘤小鼠分别给予赋形剂、萝卜硫素、TRAIL以及萝卜硫素加TRAIL处理。通过免疫组织化学法检测凋亡、血管生成和转移的标志物。
萝卜硫素增强了TRAIL对PC-3细胞的治疗潜力，并使对TRAIL耐药的LNCaP细胞敏感。萝卜硫素诱导PC-3细胞凋亡与细胞内活性氧（ROS）生成、线粒体膜电位崩溃、半胱天冬酶-3和半胱天冬酶-9激活以及DR4和DR5上调相关。萝卜硫素诱导Bax、Bak、Bim和Noxa表达，并抑制Bcl-2、Bcl-X(L)和Mcl-1表达。用抗氧化剂N-乙酰-L-半胱氨酸淬灭ROS生成可显著保护细胞免受萝卜硫素诱导的ROS生成、线粒体膜电位破坏、半胱天冬酶-3激活和凋亡。萝卜硫素通过诱导凋亡和抑制增殖来抑制原位植入的PC-3肿瘤生长，还增强了TRAIL的抗肿瘤活性。萝卜硫素上调肿瘤组织中TRAIL-R1/DR4、TRAIL-R2/DR5、Bax和Bak的表达，并抑制核因子-κB、P13K/AKT和MEK/ERK途径的激活。萝卜硫素与TRAIL联合使用在抑制血管生成和转移标志物以及激活FOXO3a转录因子方面比单独使用单一药物更有效。
萝卜硫素抑制肿瘤生长、转移和血管生成以及增强TRAIL治疗潜力的能力表明，萝卜硫素单独或与TRAIL联合可用于前列腺癌的治疗。
