尽管维生素D(VD)具有化学保护作用并增强5-氟尿嘧啶(5-FU)对结直肠癌(CRC)的细胞毒性,对其潜在的钙(Ca2)介导的抗肿瘤作用知之甚少。因此,这项研究比较了VD及其非钙质类似物,帕立骨化醇(Pcal),±5-FU与体内和体外化学预防和Ca2介导的凋亡有关。
将70只雄性小鼠分配到:阴性对照,阳性对照(PC),VD,Pcal,5-FU,VD+5-FU和Pcal+5-FU组。所有团体,除了阴性,接受两次连续的氧化偶氮甲烷(AOM)注射(10mg/Kg/周)用于CRC诱导。VD3(1000IU/kg;三次/周)和Pcal(1.25μg/kg;三次/周)注射在AOM后第16周开始,持续10周。三个连续的5-FU周期在第21周开始(50mg/Kg/周)。在HT29结肠癌细胞中应用VD3、Pcal和/或5-FU的类似方案。
PC组有丰富的恶性肿瘤,增殖标志物(survivin/CCND1)明显升高,细胞周期蛋白依赖性激酶抑制剂-1A下降,促凋亡分子(p53/BAX/细胞色素C/caspase-3),组织Ca2+浓度和Ca2+依赖性蛋白(CaSR/CAM/CAMKIIA)。所有单一疗法都同样减少了肿瘤数量和增殖标志物,同时促进了抗肿瘤分子。VD和/或5-FU,但不是Pcal单一疗法,在体内和体外增强了Ca2水平和Ca2相关分子(CaSR/CAM/CAMKIIA/BAX/细胞色素C)。然而,VD+5-FU联合治疗显示肿瘤数量最低,细胞周期的子G1期细胞数最高,除了最有效的癌基因调制,体内和体外基因和蛋白质水平的肿瘤抑制剂和Ca2相关分子。
VD3在增强5-FU细胞毒性方面优于帕立骨化醇,可能是通过上调与肿瘤抑制有关的几种Ca2相关分子。
Although vitamin D (VD) is chemoprotective and enhances 5-fluorouracil (5-FU) cytotoxicity against colorectal cancer (CRC), little is known about its potential calcium (Ca2+)-mediated anti-tumorigenic actions. Therefore, this study compared between VD and its non-calcaemic analogue, Paricalcitol (Pcal), ± 5-FU in relation to chemoprevention and Ca2+-mediated apoptosis in vivo and in vitro.
Seventy male mice were distributed to: negative controls, positive controls (PC), VD, Pcal, 5-FU, VD + 5-FU and Pcal+5-FU groups. All groups, except negative, received two consecutive azoxymethane (AOM)-injections (10 mg/Kg/week) for CRC induction. VD3 (1000 IU/kg; three times/week) and Pcal (1.25 μg/kg; three times/week) injections started week-16 post-AOM and for 10 weeks. Three successive 5-FU cycles began at week-21 (50 mg/Kg/week). Similar protocols with VD3, Pcal and/or 5-FU were applied in the HT29 colon cancer cells.
The PC group had abundant malignant tumours, markedly elevated proliferation markers (survivin/CCND1) and declines in cyclin-dependent kinase-inhibitor-1A, pro-apoptotic molecules (p53/BAX/cytochrome_C/caspase-3), tissue Ca2+ concentrations and Ca2+-dependent proteins (CaSR/CAM/CAMKIIA). All monotherapies equally reduced tumour numbers and proliferation markers whilst promoting the anti-tumorigenic molecules. VD and/or 5-FU, but not Pcal monotherapy, enhanced Ca2+ levels and Ca2+-related molecules (CaSR/CAM/CAMKIIA/BAX/cytochrome_C) in vivo and in vitro. However, VD + 5-FU co-therapy showed the lowest tumour numbers, the highest cell numbers in sub-G1 phase of cell cycle, alongside the most effective modulations of oncogenes, tumour suppressors and Ca2+-related molecules at the gene and protein levels in vivo and in vitro.
VD3 was superior than Paricalcitol in potentiating 5-FU cytotoxicity, possibly by upregulating several Ca2+-related molecules involved in tumour suppression.