大肠癌干细胞基因Bmi-1表达与大肠肿瘤组织病理特征的关系

doi:10.3969/j.issn.2095-4344.2014.06.012

摘要/Abstract

摘要：

背景：大肠癌干细胞基因Bmi-1 (B-cell-specific moloney murineleukemia virus insertion site)在调节人端粒反转录酶的转录状态和活性情况，对细胞的衰老、癌变具有重要意义。

目的：观察大肠癌干细胞基因Bmi-1的表达及其与肿瘤组织病理学变化之间的关系。

方法：采用实时荧光定量PCR技术对50例大肠癌患者肿瘤组织中Bmi-1 mRNA的表达情况进行检测，采用苏木精-伊红染色和免疫组织化学染色染色SP法测定患者肿瘤组织中Bmi-1蛋白的表达。

结果与结论：大肠癌患者的性别、年龄、肿瘤直径对肿瘤组织中大肠癌干细胞Bmi-1 mRNA的表达差异无显著性意义。在不同性别、年龄、肿瘤直径和Duke分期的大肠癌患者肿瘤组织中大肠癌干细胞Bmi-1蛋白表达差异无显著性意义。肿瘤淋巴结转移和浸润深度超过浆膜层的大肠癌患者Bmi-1 mRNA和蛋白的表达明显高于无转移和浸润深度较低的患者(P < 0.05)。大肠癌Duke分期较高的患者体内大肠癌干细胞Bmi-1 mRNA的表达也较高(P < 0.05)。结果证实，大肠癌干细胞基因Bmi-1的表达与大肠癌的转移、浸润及Duke分期的病理特征密切相关。

中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程

全文链接：

关键词: 干细胞, 肿瘤干细胞, 大肠癌, 基因, Bmi-1, 转移, 浸润, Duke分期, 分化

Abstract:

BACKGROUND: Bmi-1 (B-cell-specific moloney murineleukemia virus insertion site), a colorectal cancer stem cell gene is of great significance in the regulation of telomere reverse transcriptase activity and transcriptional status as well as cell aging and carcinogenesis.

OBJECTIVE: To investigate the correlation between Bmi-1 expression and clinicopathological changes of colorectal cancer.

METHODS: The expression of Bmi-1 mRNA in carcinoma cells was detected in 50 cases of colorectal cancer using quantitative real-time PCR. The expression of Bmi-1 protein in cancer tissue was detected by hematoxylin-eosin staining and immunohistochemical staining SP method.

RESULTS AND CONCLUSION: Sex, age, and tumor size showed no different effects on the expression of Bmi-1 mRNA. The expression of Bmi-1 protein showed no significant difference in patients who were different in sex, age, tumor size and Duke staging of tumor. The expressions of Bmi-1 mRNA and protein in patients with lymph node metastasis and depth of invasion deeper than the serosa were much higher than those in patients with no lymph node metastasis and depth of invasion shallower than the serosa (P < 0.05). The expression of Bmi-1 mRNA was much higher in patients with higher Duke staging cancer (P < 0.05). The expression of Bmi-1 mRNA and protein are closely related to different pathological features of colorectal cancer, such as metastasis, infiltration, and Duke staging.

全文链接：

Key words: intestine, large, diagnosis, differential, genes, stem cells, tissues

中图分类号:

R394.2

黄喆. 大肠癌干细胞基因Bmi-1表达与大肠肿瘤组织病理特征的关系[J]. 中国组织工程研究, 2014, 18(6): 894-899.

Huang Zhe. Correlation between Bmi-1 and clinicopathological features of colorectal cancer[J]. Chinese Journal of Tissue Engineering Research, 2014, 18(6): 894-899.

图/表（结果） 2

参考文献

[1] Malhotra S, Wang L, Bunker CH, et al. Renal dysfunction does not affect the prognostic value of myocardial iodine-123 meta-iodobenzylguanidine imaging in heart failure. Nucl Med Commun. 2014;35(1):58-63.

[2] De Luis DA, Aller R, Izaola O, et al. Relation of -55CT polymorphism of UCP3 gene with weight loss and metabolic changes after a high monounsaturated fat diet in obese non diabetic patients. Eur Rev Med Pharmacol Sci. 2013;17(20): 2810-2815.

[3] Song X, Jousilahti P, Stehouwer CD, et al. Comparison of various surrogate obesity indicators as predictors of cardiovascular mortality in four European populations. Eur J Clin Nutr. 2013;67(12):1298-1302.

[4] Yamazaki H, Mori T, Yazawa M, et al. Stem cell self-renewal factors Bmi1 and HMGA2 in head and neck squamous cell carcinoma: clues for diagnosis. Lab Invest. 2013;93(12): 1331-1338.

[5] Becker-Koji? ZA, Ureña-Peralta JR, Saffrich R, et al. A novel human glycoprotein ACA is an upstream regulator of human hematopoiesis. Bull Exp Biol Med. 2013;155(4): 536-551.

[6] 王芳,王旸,赵春松,等.Bmi-1基因对于人胚骨髓间充质干细胞增生和衰老的作用[J].首都医科大学学报,2011,32(1):60-66.

[7] Mica L, Keller C, Vomela J, et al. Obesity and overweight as a risk factor for pneumonia in polytrauma patients: a retrospective cohort study. J Trauma Acute Care Surg. 2013; 75(4):693-698.

[8] Lee J, Peschken CA, Muangchan C, et al. The frequency of and associations with hospitalization secondary to lupus flares from the 1 000 Faces of Lupus Canadian cohort. Lupus. 2013;22(13):1341-1348.

[9] Siemens H, Jackstadt R, Kaller M, et al. Repression of c-Kit by p53 is mediated by miR-34 and is associated with reduced chemoresistance, migration and stemness. Oncotarget. 2013; 4(9):1399-1415.

[10] de la Iglesia R, Lopez-Legarrea P, Abete I, et al. A new dietary strategy for long-term treatment of the metabolic syndrome is compared with the American Heart Association (AHA) guidelines: the MEtabolic Syndrome REduction in NAvarra (RESMENA) project. Br J Nutr. 2013;1-10.

[11] Abd Al Kader L, Oka T, Takata K, et al. In aggressive variants of non-Hodgkin lymphomas, Ezh2 is strongly expressed and polycomb repressive complex PRC1.4 dominates over PRC1.2. Virchows Arch. 2013;463(5):697-711.

[12] Kuang BH, Zhang MQ, Xu LH, et al. Proline-rich tyrosine kinase 2 and its phosphorylated form pY881 are novel prognostic markers for non-small-cell lung cancer progression and patients' overall survival. Br J Cancer. 2013;109(5): 1252-1263.

[13] 姚小宝,王晓侠,张少强,等.Bmi-1基因过度表达与喉癌的分化、转移及预后的关系[J].西安交通大学学报(医学版),2011,32(2): 246-249.

[14] Jensen SS, Aaberg-Jessen C, Andersen C, et al. Glioma spheroids obtained via ultrasonic aspiration are viable and express stem cell markers: a new tissue resource for glioma research. Neurosurgery. 2013;73(5):868-886.

[15] Liber A, Szajewska H. Effects of inulin-type fructans on appetite, energy intake, and body weight in children and adults: systematic review of randomized controlled trials. Ann Nutr Metab. 2013;63(1-2):42-54.

[16] Alert MD, Rastegar S, Foret M, et al. The effectiveness of a comprehensive mind body weight loss intervention for overweight and obese adults: a pilot study. Complement Ther Med. 2013;21(4):286-293.

[17] Bodegard J, Sundström J, Svennblad B, et al. Changes in body mass index following newly diagnosed type 2 diabetes and risk of cardiovascular mortality: a cohort study of 8486 primary-care patients. Diabetes Metab. 2013;39(4): 306-313.

[18] Avila JA, Avila RA, Gonçalves EM, et al. Secular trends of height, weight and BMI in young adult Brazilian military students in the 20th century. Ann Hum Biol. 2013;40(6):554-556.

[19] Fang KM, Lin TC, Chan TC, et al. Enhanced cell growth and tumorigenicity of rat glioma cells by stable expression of human CD133 through multiple molecular actions. Glia. 2013;61(9):1402-1417.

[20] Stern JS. Efficacy and tolerability of a novel herbal formulation for weight management. Obesity (Silver Spring). 2013;21(5): 921-927.

[21] Katzmarzyk PT, Hu G, Cefalu WT, et al. The importance of waist circumference and BMI for mortality risk in diabetic adults. Diabetes Care. 2013;36(10):3128-3130.

[22] Stefanov T, Vekova A, Bonova I, et al. Effects of supervised vs non-supervised combined aerobic and resistance exercise programme on cardiometabolic risk factors. Cent Eur J Public Health. 2013;21(1):8-16.

[23] Gavrilescu MM, Todosi AM, Ani?ei MG, et al. Expression of bmi-1 protein in cervical, breast and ovarian cancer. Rev Med Chir Soc Med Nat Iasi. 2012;116(4):1112-1117.

[24] Schech AJ, Kazi AA, Gilani RA et al. Zoledronic acid reverses the epithelial-mesenchymal transition and inhibits self-renewal of breast cancer cells through inactivation of NF-κB. Mol Cancer Ther. 2013;12(7):1356-1366.

[25] Black JA, White B, Viner RM, et al. Bariatric surgery for obese children and adolescents: a systematic review and meta-analysis. Obes Rev. 2013;14(8):634-644.

[26] Aaberg-Jessen C, Nørregaard A, Christensen K, et al,. Invasion of primary glioma- and cell line-derived spheroids implanted into corticostriatal slice cultures. Int J Clin Exp Pathol. 2013;6(4):546-560.

[27] Ramesh H, Reddy N, Bhatia S, et al. A 51-week, open-label clinical trial in India to assess the efficacy and safety of pancreatin 40000 enteric-coated minimicrospheres in patients with pancreatic exocrine insufficiency due to chronic pancreatitis. Pancreatology. 2013;13(2):133-139.

[28] Ho TC, Chen SL, Wu JY, et al. PEDF promotes self-renewal of limbal stem cell and accelerates corneal epithelial wound healing. Stem Cells. 2013;31(9):1775-1784.

[29] 邵惠杰,张蕾,符仲标,等.结肠腺肿瘤组织中Bmi-1和MMP-9蛋白的表达及其意义[J].实用医学杂志,2011,27(21):3859- 3862.

[30] Lawlor DA, Nordestgaard BG, Benn M, et al. Exploring causal associations between alcohol and coronary heart disease risk factors: findings from a Mendelian randomization study in the Copenhagen General Population Study. Eur Heart J. 2013;34(32):2519-2528.

[31] Kim JJ, Chae SJ, Choi YM, et al. Atherogenic changes in low-density lipoprotein particle profiles were not observed in non-obese women with polycystic ovary syndrome. Hum Reprod. 2013;28(5):1354-1360.

[32] Goel HL, Pursell B, Chang C, et al. GLI1 regulates a novel neuropilin-2/α6β1 integrin based autocrine pathway that contributes to breast cancer initiation. EMBO Mol Med. 2013;5(4):488-508.

[33] Siegrist M, Rank M, Wolfarth B, et al. Leptin, adiponectin, and short-term and long-term weight loss after a lifestyle intervention in obese children. Nutrition. 2013;29(6):851-857.

[34] Kelly AS, Rudser KD, Nathan BM, et al. The effect of glucagon-like peptide-1 receptor agonist therapy on body mass index in adolescents with severe obesity: a randomized, placebo-controlled, clinical trial. JAMA Pediatr. 2013;167(4): 355-360.

[35] 张念华,宋立兵,丁娅,等.结肠肿瘤组织中Bmi-1表达变化及意义[J].山东医药,2013,53(26):30-33.

[36] Chang Z, Li Z, Wang X, et al. Deciphering the mechanisms of tumorigenesis in human pancreatic ductal epithelial cells. Clin Cancer Res. 2013;19(3):549-559.

[37] Szabo AZ, Fong S, Yue L, et al. The CD44+ ALDH+ population of human keratinocytes is enriched for epidermal stem cells with long-term repopulating ability. Stem Cells. 2013;31(4): 786-799.

[38] Parry L, Young M, El Marjou F, et al. Evidence for a crucial role of paneth cells in mediating the intestinal response to injury. Stem Cells. 2013;31(4):776-785.

[39] van Vlerken LE, Kiefer CM, Morehouse C, et al. EZH2 is required for breast and pancreatic cancer stem cell maintenance and can be used as a functional cancer stem cell reporter. Stem Cells Transl Med. 2013;2(1):43-52.

[40] Zimmermann K. Malnutrition in pediatric patients with cancer at diagnosis and throughout therapy: a multicenter cohort study. Pediatr Blood Cancer. 2013;60(4):642-649.

[41] Dixon JB, Hur KY, Lee WJ, et al. Gastric bypass in Type 2 diabetes with BMI < 30: weight and weight loss have a major influence on outcomes. Diabet Med. 2013;30(4): e127-134.

[42] Piccinni E, Di Zenzo G, Maurelli R, et al. Induction of senescence pathways in Kindler syndrome primary keratinocytes. Br J Dermatol. 2013;168(5):1019-1026.

[43] Fiechtner L. Proximity to supermarkets associated with higher body mass index among overweight and obese preschool-age children. Prev Med. 2013;56(3-4):218-221.

[44] Erovic BM, Kim D, Cassol C, et al. Prognostic and predictive markers in medullary thyroid carcinoma. Endocr Pathol. 2012;23(4):232-242.

[45] Power BD. Changes in body mass in later life and incident dementia.Int Psychogeriatr. 2013;25(3):467-478.

[46] Kodama S, Horikawa C, Fujihara K, et al. Comparisons of the strength of associations with future type 2 diabetes risk among anthropometric obesity indicators, including waist-to-height ratio: a meta-analysis. Am J Epidemiol. 2012;176(11):959-969.

[47] Kreso A, van Galen P, Pedley NM, et al. Self-renewal as a therapeutic target in human colorectal cancer. Nat Med. 2014; 20(1):29-36.

[48] He X, Dong Y, Wu CW, et al. MicroRNA-218 inhibits cell cycle progression and promotes apoptosis in colon cancer by downregulating BMI1 polycomb ring finger oncogene. Mol Med. 2013;18:1491-1498.

[49] Semmens EO, Kopecky KJ, Grant E, et al. Relationship between anthropometric factors, radiation exposure, and colon cancer incidence in the Life Span Study cohort of atomic bomb survivors. Cancer Causes Control. 2013;24(1): 27-37.

[50] Li H, Yang G, Xiang YB, et al. Body weight, fat distribution and colorectal cancer risk: a report from cohort studies of 134-255 Chinese men and women. Int J Obes (Lond). 2012.

[51] Yang T, Fang S, Zhang HX, et al. N-3 PUFAs have antiproliferative and apoptotic effects on human colorectal cancer stem-like cells in vitro. J Nutr Biochem. 2013;24(5): 744-753.

[52] Weng MY, Li L, Feng SY, et al. Expression of Bmi-1, P16, and CD44v6 in Uterine Cervical Carcinoma and Its Clinical Significance. Cancer Biol Med. 2012;9(1):48-53.

[53] Cheasley D, Pereira L, Lightowler S, et al. Myb controls intestinal stem cell genes and self-renewal. Stem Cells. 2011; 29(12):2042-2050.

[54] Seo E, Basu-Roy U, Zavadil J, et al. Distinct functions of Sox2 control self-renewal and differentiation in the osteoblast lineage. Mol Cell Biol. 2011;31(22):4593-4608.

[55] Liu YL, Jiang SX, Yang YM, et al. USP22 acts as an oncogene by the activation of BMI-1-mediated INK4a/ARF pathway and Akt pathway. Cell Biochem Biophys. 2012; 62(1):229-235.

[56] Liu Y, Yang Y, Xu H, et al. Implication of USP22 in the regulation of BMI-1, c-Myc, p16INK4a, p14ARF, and cyclin D2 expression in primary colorectal carcinomas. Diagn Mol Pathol. 2010;19(4):194-200.

[57] Liu YL, Yang YM, Xu H, et al. Increased expression of ubiquitin-specific protease 22 can promote cancer progression and predict therapy failure in human colorectal cancer. J Gastroenterol Hepatol. 2010;25(11):1800-1805.

[58] Navarro-Alvarez N, Kondo E, Kawamoto H, et al. Isolation and propagation of a human CD133(-) colon tumor-derived cell line with tumorigenic and angiogenic properties. Cell Transplant. 2010;19(6):865-877.

[59] Li DW, Tang HM, Fan JW, et al. Expression level of Bmi-1 oncoprotein is associated with progression and prognosis in colon cancer. J Cancer Res Clin Oncol. 2010;136(7): 997-1006.

[60] Lin MX, Wen ZF, Feng ZY, et al. Association of Bmi-1 expression with clinicopathological features and prognosis of colorectal cancer. Nan Fang Yi Ke Da Xue Xue Bao. 2009; 29(9):1816-1819.

[61] Lin MX, Wen ZF, Feng ZY, et al. Expression and significance of Bmi-1 and Ki67 in colorectal carcinoma tissues. Ai Zheng. 2008;27(12):1321-1326.

[62] Ehrmann-Jósko A, Siemińska J, Górnicka B, et al. Impaired glucose metabolism in colorectal cancer. Scand J Gastroenterol. 2006;41(9):1079-1086.

[63] Reinisch C, Kandutsch S, Uthman A, et al. BMI-1: a protein expressed in stem cells, specialized cells and tumors of the gastrointestinal tract. Histol Histopathol. 2006;21(11): 1143-1149.

[64] Kim JH, Yoon SY, Kim CN, et al. The Bmi-1 oncoprotein is overexpressed in human colorectal cancer and correlates with the reduced p16INK4a/p14ARF proteins. Cancer Lett. 2004;203(2):217-224.

[65] 王海斌,王任之,刘秋龙,等.癌基因B细胞特异的莫洛尼白血病病毒插入位点1基因和埃兹蛋白在大肠癌组织的表达及意义[J].中华实验外科杂志,2013,30(6):1292-1294.

[66] 赵森林,孟镔,严东旺,等.Bmi-1基因与大肠癌术后相关性研究进展[J].局解手术学杂志,2013,22,(3):306-308.

[67] 高健,李相良.多梳基因-1在肠癌组织中的表达及其临床意义[J].中国医药科学,2011,1(22):62-63.

[68] 卢敏,沙卫红,王启仪.RNAi抑制人大肠癌LOVO细胞Bmi-1基因的表达[J].现代消化及介入诊疗,2011,16(6):362-366.

[69] 胡潇红,沙卫红,林锋,等大肠癌干细胞基因Bmi-1的表达及临床病理意义[J].现代消化及介入诊疗,2011,16(1):1-5.

[70] 佘浩清,白宁,谢彪,等.Bmi-1蛋白过表达促进大肠癌发病过程[J].当代医学,2011,17(13): 6-17.

[71] 汪云霞,魏亚明,王晓华,等.bmi-1shRNA逆转录病毒表达载体的构建及稳定转染LoVo细胞系的建立[J].肿瘤防治研究,2010, 37(3):269-273.

[72] 林妙霞,文卓夫,陈燕铭,等.Bmi-1和P16在大肠肿瘤中的表达及临床意义[J].中国热带医学,2009,9(11):2112-2114.

[73] 姚尧,李波,胡志军,等.Bmi-1在大肠癌组织中的表达及意义[J].实用医学杂志,2009,25(21):3589-3591.

[74] 虞先濬,刘辰,徐近,等.CD24+CD44+胰腺癌细胞的获取及其干细胞特性的初步鉴定[J].中国癌症杂志,2011,21(2):86-90.

[75] Balasubramanian S, Kanade S, Han B, et al. A proteasome inhibitor-stimulated Nrf1 protein-dependent compensatory increase in proteasome subunit gene expression reduces polycomb group protein level. J Biol Chem. 2012;287(43): 36179-36189.

[76] Bredella MA, McManus S, Misra M, et al. Impact of metformin monotherapy versus metformin with oestrogen-progesterone on lipids in adolescent girls with polycystic ovarian syndrome. Clin Endocrinol (Oxf). 2013;79(2):199-203.

[77] Goel HL. VEGF/neuropilin-2 regulation of Bmi-1 and consequent repression of IGF-IR define a novel mechanism of aggressive prostate cancer. Cancer Discov. 2012;2(10): 906-921.

[78] Qu J, Rizak JD, Li X, et al. Melatonin treatment increases the transcription of cell proliferation-related genes prior to inducing cell death in C6 glioma cells in vitro. Oncol Lett. 2013;6(2):347-352.

[79] Oh SY, Balch CG, Cliff RL, et al. Exposure to Penicillium mycotoxins alters gene expression of enzymes involved in the epigenetic regulation of bovine macrophages (BoMacs). Mycotoxin Res. 2013;29(4):235-243.

引言

材料方法

设计：回顾性分析。

时间及地点：于2010年1月1日至2013年6月1日在辽宁省肿瘤医院大肠外科完成。

对象：选取辽宁省肿瘤医院收治的大肠癌患者共计50例，其中男30例，女20例，年龄30-75岁，平均(60.1±5.3)岁。

纳入标准：经病理学诊断证实为大肠腺癌的患者。

排除标准：①患有其他消化道肿瘤的患者。②拒绝接受住院治疗的患者。

患者50例中，原发肿瘤尚未开始治疗患者41例，术后化疗患者9例，所有患者术前未经任何抗肿瘤治疗。高分化病例2例，中分化病例43例，低分化病例5例，含5例患者伴有结肠腺瘤，4例息肉。

根据国际联合认定肿瘤分期法Duke法，患者分为A期12例、B期19例、C期16例和D期3例^[5-7]。出现淋巴结转移患者29例。

材料：

方法：

总RNA的提取和cDNA合成：分别提取大肠癌患者肿瘤组织标本的RNA，具体操作步骤按照mRNA提取试剂盒说明书进行^[8-11]。提取的RNA纯度均满足A_{260 nm}/A_{280 nm}比值在1.7-2.0之间。取总RNA 2 μg，用M-MLV反转录酶进行cDNA合成，完成后在-20 ℃条件下保存^[12]。

实时荧光定量PCR检测：在进行荧光定量PCR反应检测时，上游引物和下游引物分别为5’-GAG GGT ACT TCA TTG ATG CCA CAA C-3’和5’-GCT GGT CTC CAG GTA ACG AAC AAT A-3’。选用SYBR Green II Master Mix试剂盒标对提取的RNA进行荧光定量PCR反应，标准品内参基因上游引物和下游引物分别为5’-TGG TCT CCT CTG ACT TCA AC-3’和5’-GTG AGG GTC TCT CTC TTC CT-3’。

大肠癌干细胞基因Bmi-1 mRNA和准品内参基因各 25 μL反应体系构成：cDNA 2 μL，mix 12.5 μL，上游引物和下游引物均为0.5 μL，Nuclease-Free Water 9.125 μL，显色液0.375 μL^[13-15]。进行反应过程及条件为：95 ℃条件下变性反应1 min，后降至78 ℃维持45 s，72 ℃ 40 s，将此步骤重复进行40次^[16-17]，检测平均吸光度值，并将所有样品在同一荧光定量PCR中进行复管检测。根据检测结果，检测肿瘤组织Bmi-1 mRNA的表达水平。

苏木精-伊红染色和免疫组织化学染色：将在患者肿瘤组织、瘤旁组织和正常组织3处采取的组织进行液氮固定，进行冰冻切片，切片厚度为4 μm^[18]。将每例患者的切片分别进行苏木精-伊红染色和免疫组织化学染色，免疫染色具体操作按照免疫试剂说明书进行^[19-21]。光学显微镜下控制染色切片显色，在蒸馏水终止染色后使用苏木精对切片进行细胞核复染。染色后切片采用不同梯度乙醇脱色，采用中性树胶进行封固^[22]。荧光染色数据结果的收集采用MJ Opticon Monitor Software Version 3.1软件，使用PBS作为第一抗体的阴性对照，并在光学显微镜下观察染色情况，将观察结果进行比较。

主要观察指标：大肠癌患者肿瘤组织Bmi-1 mRNA和蛋白的表达情况。

统计学分析：采用SPSS 18.0 for windows软件对结果数据统计学处理，组间计数资料的差异比较采用卡方检验或Wilcoxon秩和检验，组间计量资料的差异比较采用Mann-Whitney U检验检测，P < 0.05为差异有显著性意义。

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讨论

大肠癌是由于患者结肠和直肠因慢性炎症、腺瘤、遗传作用等致癌因素刺激，使患者结肠和直肠出现癌变^[23-25]。其主要特点为早期癌变时机体无明显异常，偶见消化不良、腹部不适、大便潜血等症状，往往蔓延至肿瘤继续发展引起患者严重腹部反应和消化功能异常患者方引起重视^[25-27]。

大肠癌因其较强的转移特性和浸润特性可引起腹部脏器大范围内出现病变，临床表现因不同脏器受累复杂^[28]。大肠癌干细胞基因Bmi-1是一种抑制靶基因的蛋白质合成的调控基因，可通过其自身调控位点形成复合物来调控相邻基因^[29-31]。

研究已明确Bmi-1基因在人体位于第10号染色体的断臂13区，其结构上为“H-T-H-T”DNA结合模体和位于N末端的ring finger domain共同构成，主要调控一种核蛋白的表达^[31-32]。“H-T-H-T”DNA结合模体对于粒酶活性以及细胞永生化都具有重要意义，从而在结构和功能上决定了Bmi-1基因对于肿瘤以及正常细胞分化的重要作用^[33-35]。

Bmi-1基因主要通过对p16INK4a和p19ARF这两种肿瘤抑制基因的负性调控来作用于癌细胞的发展分化^[36-37]。若细胞出现Bmi-1基因高度表达，则可产生INK4a和ARF复合物，对INK4a和ARF这两种抑癌基因的表达产生高度抑制，导致其相邻基因的沉默，从而致使癌变恶化^[38-40]。

研究显示，INK4a所调控的p16INK4a蛋白可对细胞周期素D1产生较大程度的抑制作用，进而使Rb基因始终处于低磷酸化状态，降低了其与E2F形成复合物抑制细胞转录促发细胞凋亡的作用^[41-43]。ARF复合物的形成同样抑制了ARF调控p19ARF与Mdm2进行结合，调控p53对癌基因的抑制作用^[44]。此外，Bmi-1基因还可间接影响端粒酶的活性，致使细胞增殖速度加快，对肿瘤的产生和发展提供必要条件^[44-46]。

本次实验通过SYBR Green II Master Mix试剂盒标Bmi-1 RNA荧光定量PCR反应、苏木精-伊红染色和免疫组织化学染色对大肠癌患者肿瘤组织Bmi-1 RNA及蛋白进行检测，可得出大肠肿瘤组织中Bmi-1 RNA以及Bmi-1蛋白的表达量较多，此结论说明Bmi-1基因在肿瘤组织中过度表达^[47-76]。

实验结果还显示，出现淋巴结转移的大肠癌细胞中Bmi-1 RNA及蛋白的表达明显高于未出现淋巴结转移的癌细胞，说明大肠癌淋巴结的转移与癌细胞中Bmi-1 RNA以及Bmi-1蛋白的表达密切相关；肿瘤浸润深度超过浆膜层的Bmi-1 RNA以及Bmi-1蛋白的表达明显高于浸润深度不超过肌层的癌细胞。

实验结果显示浸润深度越深则Bmi-1 RNA以及Bmi-1蛋白的表达越明显；Duke分期为C和D期的大肠癌患者仅Bmi-1 RNA的表达水平高于Duke分期为A和B期的癌细胞，但在Bmi-1蛋白表达水平上，二者之间差异无显著性意义，这可能由于不同Duke分期，肿瘤组织病理变化不同所致的影响^[77-79]。

综上所述，大肠癌的转移情况、浸润情况、Duke分期和分化情况等病理特征与大肠癌干细胞基因Bmi-1在蛋白和RNA的表达情况密切相关，检测Bmi-1基因的表达水平对临床诊疗具有重要意义，但其是否能作为大肠癌诊断标志物尚需多中心大样本的随机对照试验和循证医学证据来证实。

中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程
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