Zhang Biao, Guo Dan-Dan, Zheng Jia-Ying, Wu Yan-An
Department of Clinical Laboratory, Fujian Provincial Hospital, Provincial Clinical College, Fujian Medical University, Fuzhou, China.
Eur J Cancer Prev. 2018 Jan;27(1):20-26. doi: 10.1097/CEJ.0000000000000410.
Kruppel like factor 6 (KLF6), a member of KLF family, which has classic zinc finger structure, is broadly considered to have anticancer activity. The role of SV2 variant, one of KLF6 alternative splicing isoforms has not yet been definite in the colorectal cancer. This study aimed to detect the expression of the KLF6-SV2 in colorectal cancer and investigate its impact on cell proliferation and apoptosis. qRT-PCR was used to quantitatively determine KLF6-SV2 mRNA expression in colorectal cancer samples, corresponding normal tissue, normal colonic mucosal cell line FHC and seven colorectal cancer cell lines. SW480 and SW620 cell models with over-expressing KLF6-SV2 were constructed. Cell proliferation, cell cycle and apoptosis were measured respectively using MTT assay, DNA ploidy detection and Annexin V flow cytometry. Meanwhile, expression of p53, p21 and Bax were detected by qRT-PCR and western blot. The mRNA expression level of KLF6-SV2 in colorectal cancer tissues (0.783±0.409) was decreased than in corresponding normal tissues (1.086±0.449) (P<0.01), and expression in SW480 and SW620 were lower than in FHC, HCT116, LoVo, HT29, Caco-2 and RKO. In cell lines over-expressing KLF6-SV2, cell proliferation was markedly suppressed, cell cycle was blocked and cell apoptosis was significantly induced. Simultaneously, expression of p21 and Bax were remarkably up-regulated, while p53 remained unchanged. Decreased expression of KLF6-SV2 may be associated with the occurrence and development of colorectal cancer. KLF6-SV2 plays a role as tumor suppressor by efficiently blocking cell proliferation, arresting cell cycle and inducing apoptosis in colorectal cancer, which may be related to increased expression of p21 and Bax.
Kruppel样因子6（KLF6）是KLF家族的成员之一，具有典型的锌指结构，被广泛认为具有抗癌活性。KLF6可变剪接异构体之一的SV2变体在结直肠癌中的作用尚未明确。本研究旨在检测KLF6-SV2在结直肠癌中的表达，并探讨其对细胞增殖和凋亡的影响。采用qRT-PCR定量检测结直肠癌样本、相应正常组织、正常结肠黏膜细胞系FHC和7种结直肠癌细胞系中KLF6-SV2 mRNA的表达。构建了过表达KLF6-SV2的SW480和SW620细胞模型。分别采用MTT法、DNA倍体检测和Annexin V流式细胞术检测细胞增殖、细胞周期和凋亡情况。同时，通过qRT-PCR和western blot检测p53、p21和Bax的表达。结直肠癌组织中KLF6-SV2的mRNA表达水平（0.783±0.409）低于相应正常组织（1.086±0.449）（P<0.01），且在SW480和SW620中的表达低于FHC、HCT116、LoVo、HT29、Caco-2和RKO。在过表达KLF6-SV2的细胞系中，细胞增殖明显受到抑制，细胞周期被阻滞，细胞凋亡明显增加。同时，p21和Bax的表达显著上调，而p53保持不变。KLF6-SV2表达降低可能与结直肠癌的发生发展有关。KLF6-SV2通过有效阻断结直肠癌细胞增殖、阻滞细胞周期和诱导凋亡发挥肿瘤抑制作用，这可能与p21和Bax表达增加有关。
