Department of General Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai Minimally Invasive Surgery Center, Shanghai 200025, China.
World J Gastroenterol. 2012 Jun 7;18(21):2640-8. doi: 10.3748/wjg.v18.i21.2640.
To evaluate the effect of nigericin on colorectal cancer and to explore its possible mechanism.
The human colorectal cancer (CRC) cell lines HT29 and SW480 were treated with nigericin or oxaliplatin under the conditions specified. Cell viability assay and invasion and metastasis assay were performed to evaluate the effect of nigericin on CRC cells. Sphere-forming assay and soft agar colony-forming assay were implemented to assess the action of nigericin on the cancer stem cell properties of CRC cells undergone epithelial-mesenchymal transition (EMT).
Compared with oxaliplatin, nigericin showed more toxicity for the HT29 cell line (IC50, 12.92 ± 0.25 μmol vs 37.68 ± 0.34 μmol). A similar result was also obtained with the SW116 cell line (IC50, 15.86 ± 0.18 μmol vs 41.02 ± 0.23 μmol). A Boyden chamber assay indicated that a significant decrease in the number of HT29 cells migrating through polyvinylidene fluoride membrane was observed in the nigericin-treated group, relative to the vehicle-treated group [11 ± 2 cells per high-power field (HPF) vs 19.33 ± 1.52 cells per HPF, P < 0.05]. Compared to the control group, the numbers of HT29 cells invading through the Matrigel-coated membrane also decreased in the nigericin-treated group (6.66 ± 1.52 cells per HPF vs 14.66 ± 1.52 cells per HPF, P < 0.05). Nigericin also reduced the proportion of CD133+ cells from 83.57% to 63.93%, relative to the control group (P < 0.05). Nigericin decreased the number of spheres relative to the control group (0.14 ± 0.01 vs 0.35 ± 0.01, P < 0.05), while oxaliplatin increased the number of spheres relative to the control group (0.75 ± 0.02 vs 0.35 ± 0.01; P < 0.05). Nigericin also showed a decreased ability to form colonies under anchorage-independent conditions in a standard soft agar assay after 14 d in culture, relative to the control group (1.66 ± 0.57 vs 7 ± 1.15, P < 0.05), whereas the colony numbers were higher in the oxaliplatin group relative to the vehicle-treated controls (14.33 ± 0.57 vs 7 ± 1.15, P < 0.05). We further detected the expression of E-cadherin and vimentin in cells treated with nigericin and oxaliplatin. The results showed that HT29 cells treated with nigericin induced an increase in E-cadherin expression and a decrease in the vimentin expression relative to vehicle controls. In contrast, oxaliplatin downregulated the expression of E-cadherin and upregulated the expression of vimentin in HT29 cells relative to vehicle controls.
This study demonstrated that nigericin could partly reverse the EMT process during cell invasion and metastasis.
评估 Nigericin 对结直肠癌的作用，并探讨其可能的机制。
用 Nigericin 或奥沙利铂处理人结直肠癌细胞系 HT29 和 SW480，进行细胞活力测定和侵袭转移实验，评价 Nigericin 对 CRC 细胞的作用。采用球体形成实验和软琼脂集落形成实验，评估 Nigericin 对经历上皮间质转化（EMT）的 CRC 细胞的癌症干细胞特性的作用。
与奥沙利铂相比，Nigericin 对 HT29 细胞系的毒性更强（IC50，12.92±0.25μmol 对 37.68±0.34μmol）。在 SW116 细胞系中也得到了类似的结果（IC50，15.86±0.18μmol 对 41.02±0.23μmol）。Boyden 室实验表明，与载体处理组相比，Nigericin 处理组 HT29 细胞穿过聚偏二氟乙烯膜的迁移数量明显减少[11±2 个细胞/高倍视野（HPF）对 19.33±1.52 个细胞/HPF，P<0.05]。与对照组相比，Nigericin 处理组穿过 Matrigel 涂层膜的 HT29 细胞侵袭数量也减少（6.66±1.52 个细胞/HPF 对 14.66±1.52 个细胞/HPF，P<0.05）。Nigericin 还使 CD133+细胞的比例从 83.57%降至 63.93%，与对照组相比（P<0.05）。与对照组相比，Nigericin 减少了球体的数量（0.14±0.01 对 0.35±0.01，P<0.05），而奥沙利铂增加了球体的数量（0.75±0.02 对 0.35±0.01；P<0.05）。Nigericin 还在标准软琼脂测定中显示出在培养 14 天后在无锚定状态下形成菌落的能力降低，与对照组相比（1.66±0.57 对 7±1.15，P<0.05），而奥沙利铂组的菌落数量高于载体对照组（14.33±0.57 对 7±1.15，P<0.05）。我们进一步检测了 Nigericin 和奥沙利铂处理的细胞中 E-钙粘蛋白和波形蛋白的表达。结果表明，与载体对照组相比，Nigericin 处理的 HT29 细胞诱导 E-钙粘蛋白表达增加，波形蛋白表达减少。相反，奥沙利铂下调 HT29 细胞中 E-钙粘蛋白的表达，上调波形蛋白的表达。
本研究表明，Nigericin 可部分逆转细胞侵袭和转移过程中的 EMT 过程。
