ATRA enhances bystander effect of suicide gene therapy in the treatment of prostate cancer
ATRA enhances bystander effect of suicide gene therapy in the treatment of prostate cancer
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DOI：
10.1016/j.urolonc.2007.08.010
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发表时间：
2008-07-01
影响因子：
2.7
通讯作者：
Wen, Duangai
中科院分区：
文献类型：
--
作者：
Chen, Weiguo;Yan, Chunyin;Wen, Duangai
目的：全反式维甲酸(ATRA)可通过改变细胞间隙连接通讯(GJIC)和连接蛋白(CX)43的表达来抑制多种恶性肿瘤的生长。在此，我们报道了ATRA对GJIC的改变可能直接增强自杀基因治疗前列腺癌的旁观者效应(BE)。方法：不同浓度的ATRA作用于PC-3细胞不同时间。流式细胞仪检测Cx43阳性细胞数，刮擦负载染料转移法检测细胞GJIC功能。用全反式维甲酸联合编码单纯疱疹病毒胸苷激酶的腺病毒/更昔洛韦(Ad-TK/GCV)系统处理细胞，并在体内和体外评价BE对雄激素非依赖性前列腺癌的治疗作用。用半定量逆转录聚合酶链式反应(RT-PCR)和免疫组织化学方法检测肿瘤组织中Cx43基因和蛋白的表达。结果：ATRA能明显增加肿瘤组织中Cx43阳性细胞的数量，并呈时间和剂量依赖关系(P<；0.05)。全反式维甲酸可使PC-3细胞的GJIC功能增强3~5倍，但不能增强PC-3细胞的GCV毒性。在混合实验中，当TK阳性细胞比例在30%~60%时，ATRA对细胞的杀伤作用明显高于未处理细胞(P<；0.05)，当TK阳性细胞比例为30%时，细胞杀伤作用达到50%，但在未处理细胞中，TK阳性细胞比例达到60%时才出现同样的结果。治疗3周后，联合应用全反式维甲酸和环丙沙星的小鼠的Ad-TK感染肿瘤明显小于单用环丙沙星或全反式维甲酸的小鼠(P<；0.05)。然而，从治疗的第四周开始，GCV组和GCV+ATRA组的肿瘤生长抑制没有差异(P>；0.05)，因为后者的两个肿瘤开始比对照组的肿瘤生长得更快。结论：ATRA可通过增强体内外BE而提高前列腺癌自杀基因治疗中的细胞杀伤效率。ATRA对CXS和GJIC的诱导可能为自杀基因治疗提供了一种选择性。未来的研究应该集中在安全性和为患者量身定做这种合作疗法上。(C)2008 Elsevier Inc.保留所有权利。
Objectives: All-trans retinoic acid (ATRA) has been shown to inhibit the growth of many malignancies by altering gap junctional intercellular communication (GJIC) and the expression of connexin (Cx) 43. Here, we report that the alteration of GJIC by ATRA may directly enhance the bystander effect (BE) of suicide gene therapy against prostate cancer in vitro and in vivo.Methods: PC-3 cells were exposed to different concentrations of ATRA for varying lengths of time in culture. Flow cytometry was performed to measure Cx43-positive cells and the GJIC function of the cells was examined with the scrape-loading dye transfer assay. Cells were treated with ATRA in combination with an adenovirus/ganciclovir (Ad-TK/GCV) system encoding herpes simplex virus-thymidine kinase, and the BE was assessed in the treatment of androgen-independent prostate cancer both in vitro and in vivo. Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were performed to assess the expression of Cx43 mRNA and protein in tumor tissues.Results: ATRA significantly increased the amount of Cx43-positive cells in a time- and dose-dependent manner (P < 0.05). GJIC functions were enhanced 3- to 5-fold in the presence of ATRA, although ATRA did not augment GCV toxicity of PC-3 cells. In the mixing assay, ATRA significantly increased cell killing when the ratio of TK-positive cells in the coculture ranged from 30% to 60% compared with ATRA-untreated cell (P < 0.05), and attained 50% cell killing cells when the ratio of TK-positive cell was 30%, but the same result did not appear until the ratio of TK-positive cell was up to 60% in the ATRA-untreated cell. Mice treated with a combination of ATRA and GCV had significantly smaller Ad-TK infected tumors than those treated with GCV or ATRA alone after 3-weeks of therapy (P < 0.05). However, from the fourth-week of therapy, there was no difference in tumor growth inhibition between GCV treatment and GCV + ATRA treatment (P > 0.05), as two tumors in the latter group started to grow more quickly than tumors in the control group. This phenomenon was not found in other groups.Conclusions: ATRA could enhance the efficiency of cell killing in suicide gene therapy against prostate cancer by strengthening the BE in vitro and in vivo. Induction of Cxs and GJIC by ATRA might provide an element of selectivity to suicide gene therapy. Future studies should focus on safety and tailoring this cooperative therapy to the patient. (C) 2008 Elsevier Inc. All rights reserved.