Paukovcekova Silvia, Skoda Jan, Neradil Jakub, Mikulenkova Erika, Chlapek Petr, Sterba Jaroslav, Richardson Des R, Veselska Renata
Department of Experimental Biology, Faculty of Science, Masaryk University, 61137 Brno, Czech Republic.
International Clinical Research Center, St. Anne's University Hospital, 65691 Brno, Czech Republic.
Cancers (Basel). 2020 Dec 15;12(12):3781. doi: 10.3390/cancers12123781.
Combining low-dose chemotherapies is a strategy for designing less toxic and more potent childhood cancer treatments. We examined the effects of combining the novel thiosemicarbazones, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), or its analog, di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT), with the standard chemotherapies, celecoxib (CX), etoposide (ETO), or temozolomide (TMZ). These combinations were analyzed for synergism to inhibit proliferation of three pediatric tumor cell-types, namely osteosarcoma (Saos-2), medulloblastoma (Daoy) and neuroblastoma (SH-SY5Y). In terms of mechanistic dissection, this study discovered novel thiosemicarbazone targets not previously identified and which are important for considering possible drug combinations. In this case, DpC and Dp44mT caused: (1) up-regulation of a major protein target of CX, namely cyclooxygenase-2 (COX-2); (2) down-regulation of the DNA repair protein, O-methylguanine DNA methyltransferase (MGMT), which is known to affect TMZ resistance; (3) down-regulation of mismatch repair (MMR) proteins, MSH2 and MSH6, in Daoy and SH-SY5Y cells; and (4) down-regulation in all three cell-types of the MMR repair protein, MLH1, and also topoisomerase 2α (Topo2α), the latter of which is an ETO target. While thiosemicarbazones up-regulate the metastasis suppressor, NDRG1, in adult cancers, it is demonstrated herein for the first time that they induce NDRG1 in all three pediatric tumor cell-types, validating its role as a potential target. In fact, siRNA studies indicated that NDRG1 was responsible for MGMT down-regulation that may prevent TMZ resistance. Examining the effects of combining thiosemicarbazones with CX, ETO, or TMZ, the most promising synergism was obtained using CX. Of interest, a positive relationship was observed between NDRG1 expression of the cell-type and the synergistic activity observed in the combination of thiosemicarbazones and CX. These studies identify novel thiosemicarbazone targets relevant to childhood cancer combination chemotherapy.
联合使用低剂量化疗是一种设计毒性更低、效力更强的儿童癌症治疗方案的策略。我们研究了将新型硫代氨基脲、二 - 2 - 吡啶基酮4 - 环己基 - 4 - 甲基 - 3 - 硫代氨基脲（DpC）或其类似物二 - 2 - 吡啶基酮 - 4,4 - 二甲基 - 3 - 硫代氨基脲（Dp44mT）与标准化疗药物塞来昔布（CX）、依托泊苷（ETO）或替莫唑胺（TMZ）联合使用的效果。分析了这些联合用药对三种儿科肿瘤细胞类型（即骨肉瘤（Saos - 2）、髓母细胞瘤（Daoy）和神经母细胞瘤（SH - SY5Y））增殖的抑制协同作用。在机制剖析方面，本研究发现了以前未确定的新型硫代氨基脲靶点，这些靶点对于考虑可能的药物联合很重要。在这种情况下，DpC和Dp44mT导致：（1）CX的主要蛋白靶点环氧合酶 - 2（COX - 2）上调；（2）已知会影响TMZ耐药性的DNA修复蛋白O - 甲基鸟嘌呤 - DNA甲基转移酶（MGMT）下调；（3）Daoy和SH - SY5Y细胞中错配修复（MMR）蛋白MSH2和MSH6下调；（4）在所有三种细胞类型中MMR修复蛋白MLH1以及拓扑异构酶2α（Topo2α，后者是ETO的靶点）下调。虽然硫代氨基脲在成人癌症中上调转移抑制因子NDRG1，但本文首次证明它们在所有三种儿科肿瘤细胞类型中诱导NDRG1，证实了其作为潜在靶点的作用。事实上，siRNA研究表明NDRG1负责MGMT下调，这可能预防TMZ耐药性。研究硫代氨基脲与CX、ETO或TMZ联合使用的效果时，使用CX获得了最有前景的协同作用。有趣的是，观察到细胞类型的NDRG1表达与硫代氨基脲和CX联合使用时观察到的协同活性之间存在正相关。这些研究确定了与儿童癌症联合化疗相关的新型硫代氨基脲靶点。
