摘要
背景
同源框基因( Homeobox Genes)最早在果蝇中发现,存在于酵母到人类几
乎所有的真核生物细胞中。其含有称为同源框(Homeobox)的 183bp 高度保守
的核苷酸序列,是真核生物转录因子。同源框基因对胚胎发育有重要的调节作用,
近年的研究发现一些肿瘤的发生、发展与调控细胞分化的同源框基因家族的异常
表达密切相关。同源框基因 Nkx3.1 定位于小鼠 14 号染色体的中间区,与 NK 家
族的 NK3 有最高同源性。人类 Nkx3.1 写作 NKX3.1, cDNA 全长 3266bp,开
放阅读框(ORFs)705bp,定位于 8p21,正好是前列腺癌发病时频繁发生丢失的“热
斑区”。研究表明,NKX3.1 几乎只局限于前列腺组织表达,特异度超过前列腺
特异抗原 PSA;其 mRNA 转录水平受雄激素调节;对前列腺器官的发生、分化、
发育及成熟器官的功能维持有重要作用。另外,有实验提示 NKX3.1 表达缺失与
激素抵抗性前列腺癌和晚期前列腺癌关系密切;Nkx3.1 可抑制其表达缺失株前
列腺癌细胞体外生长,接种裸鼠后其肿瘤生长能力明显降低; Nkx3.1 失功能的
Nkx3.1 突变基因工程化鼠增龄饲养,发现有前列腺上皮内瘤(PIN)产生,类似
于人类组织发现;实验中 Nkx3.1 与抑癌基因 PTEN 同时丧失功能的小鼠发生了
前列腺癌,并证实淋巴结转移,提示 Nkx3.1 功能丧失是前列腺癌发生过程中的
严重事件――因而,Nkx3.1 可能是新的前列腺组织特异的候选抑癌基因。NKX3.1
有正常变异但未发现影响其功能,前列腺癌病理组织中亦未发现其编码区存在变
异,因而其失活方式可能是表达缺失而非变异。PTEN 是近年来发现的“广谱”
抑癌基因,定位于 10q23,此区在进展期前列腺癌频繁发生缺失,因而 PTEN 被
认为在前列腺癌发病中是一个中央调节因子。
本课题拟采用免疫组化技术,检测一组前列腺恶性肿瘤中前列腺特异性同源
框基因 NKX3.1 与 PTEN 基因的表达情况,并分析两者间可能存在的关联。并采
用目前分子生物学实验室较为成熟与常用的脂质体介导的真核基因转移技术,利
用携带有 NKX3.1 基因 cDNA(OFRs)全长序列的真核基因表达载体 pcDNA3.1
(+)-NKX3.1,稳定转染 NKX3.1 表达缺失的人雄激素非依赖型前列腺癌细
胞株 PC3,获得稳定表达 NKX3.1 蛋白的 PC3-NKX3.1 细胞株,观察 NKX3.1
基因转染对 PC3 细胞的生物学效应。进一步进行裸鼠肿瘤接种,观察 NKX3.1
基因转染后 PC3 裸鼠实验动物致瘤能力的变化,探讨 NKX3.1 基因的生物学功
能与意义,以及为未来其可能的作为前列腺癌肿瘤标志物与基因治疗靶点的潜在
价值提供实验依据。
第一部分 前列腺特异性同源框基因 NKX3.1 与抑癌基因 PTEN 在前列腺癌组织
中表达的免疫组化研究
目的
免疫组化方法检测前列腺恶性肿瘤与良性前列腺增生组织标本中前列腺同
源框基因 NKX3.1 与抑癌基因 PTEN 的表达情况,并分析二者间的相关性。
材料与方法
前列腺恶性肿瘤标本 31 例,其中腺癌 30 例,肉瘤 1 例;良性前列腺增生
标本 10 例。
所有标本均病理检验证实诊断,两步法分别行 NKX3.1 与 PTEN 抗体的免
疫组化染色,HRP 标记的二抗加 DAB 显色;光镜下观察,阳性反应为预期的细
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胞定位处出现棕黄色染色,高倍镜下阳性细胞数>50%时为强阳性(++)。
SPSS11.0 统计软件进行统计分析,行χ2检验并分别计算 Kappa 系数与 Gamma
系数。
结果
NKX3.1 与 PTEN 在前列腺恶性肿瘤标本中阳性率总分别为 48.39%与 29.03
%,良性前列腺增生为 70%与 50%,与文献报道中数据相近。Kappa 系数与
Gamma 系数均提示 NKX3.1 与 PTEN 基因在本组中的表达未发现明确相关性。
结论
本研究采用免疫组化方法检测的前列腺恶性组织标本中前列腺特异性同源
框基因 NKX3.1 与抑癌基因 PTEN 的表达与文献报道相近,但未发现二者的表达
之间存在明确的相关性。
BACKGROUND:
Homeobox genes were firstly found in Drosophila Bagpipe, exist broadly in the
creatures from yeast to human being. Containing a 183bp ribonucleotide fragment
named Homeobox, all homeobox genes play a role of eukaryotic transcriptional factor.
Homeobox genes are important regulators in embryogenesis, recent findings suggest
that they are closely related to some malignant neoplasm’s genesis, development, as
regulator of cell differentiation. Homeobox genes Nkx3.1 maps to mid-region of
mouse chromosome 14, has topmost homogeneity with homeobox gene NK family.
Human’s Nkx3.1 has been written as NKX3.1,with 3266bp full cDNA length, 705bp
open reading frame(ORFs),maps to chromosome 8p21,just the “hot spot”
superposition site that frequently lost in prostate carcinoma. Researches suggest that
NKX3.1 nearly only expresses in prostate tissue, has higher specificity than prostate
specific antigen(PSA);its mRNA transcriptional level is regulated by androgen; plays
a important role in the genesis, differentiation, development and function maintenance
of prostate organ. In addition, some experimental results indicate that depletion of
NKX3.1 expression is strongly related with hormone-resistance prostate carcinoma
and late phase prostate cancer; in vitro Nkx3.1 can suppresses the growth of Nkx3.1
loss-of-expression prostate carcinoma cell, tumor growth ability decreases after
inoculation into nude mouse; in those enhanced-age Nkx3.1 null mutant mice induced
by genetic engineering method, prostatic intraepithelial neoplasia(PIN) has been
found, and resemble the findings in human tissue; in experiments, the mice of
compound loss-of-function of Nkx3.1 and PTEN genes developed invasive prostatic
carcinoma, and lymph node metastasis were confirmed; these demonstrate that
Nkx3.1 loss-of-function is a critical event in prostate cancer
initiation.— herein,Nkx3.1 may be a new prostate tissue specific candidate
tumor-suppressing gene.NKX3.1 normal mutation doesn’t influence its function, its
coding region hasn’t been found mutation in prostate cancer pathological tissue, so its
loss-of-function manner may be expression depletion but not mutation. PTEN is a
broad spectrum tumor-suppressing gene found in recent years, maps to 10q23,a
frequently lost in progressing-phase prostatic cancer, thus PTEN has been regarded as
a central regulator in prostatic carcinogenesis.
This study plans to use immunohistochemical technique, to examine expression of
prostate specific homeobox gene NKX3.1 and tumor-suppressing gene PTEN in a
serial specimen of prostate malignant tumors, and probe into the relationship between
these two genes; by mature liposome-induced gene transferring technique currently
broadly used in molecular biology labs, using a eukaryotic gene expression vector
pcDNA3.1(+)-NKX3.1 which carrying NKX3.1 cDNA(ORFs) full length sequences,
we plans to transfect NKX3.1 loss-of-expression human androgen-independent
prostatic cancer cell line PC3, obtain the cell line PC3-NKX3.1 which stably
expresses NKX3.1 protein, and investigate the biologic effects that derived from
NKX3.1 transfection. Moreover, we will inoculate nude mice with these cells, to
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explore the change of tumor-growth ability in nude mice, and discuss biologic
function and significance of NKX3.1 gene, and to provide experimental evidence for
its possible utilities as a tumor marker and gene-therapy target site in the future.
Part I Immunohistochemical Research on the Expression of Prostate Specific
Homeobox NKX3.1 & Tumor Suppressing Gene PTEN in Prostatic Carcinoma
Tissues
OBJECTIVE
To investigate the expression of prostatic specific homeobox gene NKX3.1 and
tumor suppression gene PTEN in prostate malignant tumors and benign prostate
hyperplasia tissue specimen by immunohistochemical assay method, and analyse the
relationship between the two genes.
MATERIAL AND METHODS
Prostate maligna
引文
1.McGmnis W,Garber RL,Wirz J,et al.A homologous protein coding sequence in
Drosophia homeotic genes and its con-servation in other metazoans.Cell,1984,37:403
2.Scott MP,Weiner AJ.Structure alrelationship samong genes that control development:
sequence homology between the antenapedia, ul-tra bithorax and fushitarazu loci of
Drosophila. Proc NatlAcad Sci USA 1984,81:4115
3.Steadman DJ,Giuffrida D,Gelmann EP.DNA-binding sequence of the human
prostate-specific homeodomain protein NKX3.1.Nucleic Acids Research, 2000, 28,12:
2389-2395
4. Cha MH, Yong WM, Lee SM,et al. The biochemical and molecular characterization
of recombinant Bacillus subtilis tripeptidase (PepT) as a zinc-dependent
metalloenzyme. Mol Cells. 2000 Aug 31;10(4):423-31.
5.Stein S,Fritsh R,Lemaire L,et al.Checklist.vertebrate homeobox genes. Mech
Dev,1996,55:91-108.
6. Collio C,Barba P,Freschi G,et al.Expression and structure of Hox genes in
Willms’tumor.Int j Oncol,1995,7(6):1145-1150
7.Arakawa H,Nakamura T,Zhadanov AB,et al.Identification and characterization of
the ARP1 gene,a target for the human acute leukemia ALL1 gene.Proc Natl Acad Sci
USA,1998,95(8):4573-4578
8. Bieberich CJ, Fujita K, He WW, Jay G,et al. Prostate-specific and
androgen-dependent expression of a novel homeobox gene. J Biol Chem. 1996 Dec
13;271(50):31779-82
9. Korkmaz KS, Korkmaz CG, Ragnhildstveit E. Full-length cDNA sequence and
genomic organization of human NKX3A - alternative forms and regulation by both
androgens and estrogens.Gene. 2000 Dec 30;260(1-2):25-36
10.He WW, Sciavolino PJ, Wing J, Augustus M, et al. A novel human
prostate-specific, androgen-regulated homeobox gene (NKX3.1) that maps to 8p21, a
region frequently deleted in prostate cancer.Genomics. 1997 Jul 1;43(1):69-77
11.Tanaka M,Lyons GE,Izumo S. Expression of the Nkx3.1 homobox gene during pre
and postnatal development.Mech Dev,1999,85(2):179-182
12. Ornstein DK, Cinquanta M, Weiler S, et al. Expression studies and mutational
analysis of the androgen regulated homeobox gene NKX3.1 in benign and malignant
15
prostate epithelium. J Urol 2001 Apr;165(4):1329-34
13. Sciavoline PJ Abrams EW, Yang L. Tissue-specific expression of murine Nkx3.1
in the male urogenital system.Dev Dyn 1997 ,209(1):127-38
14.Korkmaz KS,Korkmaz CG,Ragnhildstveit E,et al.Full-length cDNA sequence and
genomic organization of human NKX3A-alternative forms and regulation by both
androgens and estrogens. Gene,2000;260,1:25-36
15.Gelmann EP,Bowen C,Bubendorf L.Expression of NKX3.1 in normal and
malignant tissues. Prostate,2003,55:111~117
16.Monica K,galili N,Nourse J,et al.PBX2 and PBX3:new homeobox genes with
extensive homology the human proto-oncogene PBX1.Mol cell Biol,1991;11(12):
6149-6157
17. Vocke CD, Pozzatti RO, Bostwick DG. Analysis of 99 microdissected prostate
carcinomas reveals a high frequency of allelic loss on chromosome 8p12-21.Cancer
Res.1996,15;56(10):2411-6
18.Suzuki H, Emi M, Komiya A, Fujiwara et al. Localization of a tumor suppressor
gene associated with progression of human prostate cancer within a 1.2 Mb region of
8p22-p21.3.Genes Chromosomes Cancer. 1995,13(3):168-74
19.Ichikawa T,Nihei N,Suzuki H,et al.Suppression of metastasis of rat prostatic cancer
by introducing human chromosome 8.Cancer Res. 1994,1;54(9):2299-302
20. Kim MJ, Bhatia-Gaur R, Banach-Petrosky WA. Nkx3.1 mutant mice recapitulate
early stages of prostate carcinogenesis. Cancer Res 2002,1;62(11):2999-3004
21.Bhatia-Gaur R, Donjacour AA, Sciavolino PJ,et al. Roles for Nkx3.1 in prostate
development and cancer. Genes Dev 1999,15;13(8):966-77
22. Park JH, Walls JE, Galvez JJ, et al. Prostatic intraepithelial neoplasia in
genetically engineered mice. Am J Pathol 2002,161(2):727-35
23.Abate-Shen C, Banach-Petrosky WA, Sun X,et al.Nkx3.1; Pten Mutant Mice
Develop Invasive Prostate Adenocarcinoma and Lymph Node Metastases.Cancer Res,
2003;63,15:3886–3890
24. Magee JA, Abdulkadir SA, Milbrandt J. Haploinsufficiency at the Nkx3.1 locus. A
paradigm for stochastic,dosage-sensitive gene regulation during tumor
initiation.Cancer Cell,2003 ,3(3):273-83
25.Abdulkadir SA, Magee JA, Peters TJ, et al. Conditional loss of Nkx3.1 in adult
mice induces prostatic intraepithelial neoplasia. Mol Cell Biol 2002,22(5):1495-503
26. Gelmann EP, Steadman DJ, Ma J, et al.Occurrence of NKX3.1 C154T
16
polymorphism in men with and without prostate cancer and studies of its effect on
protein function. Cancer Res,2002 1;62(9):2654-9
27.Voeller HJ,Augustus I,Iadike V,et al.Coding region of NKX3.1,a prostate-specific
homeobox gene on 8P21,is not mutated in human prostate.Cancer Res,1997,57:4455
-4459
28. Kim MJ, Bhatia-Gaur R, Banach-Petrosky WA. Nkx3.1 mutant mice recapitulate
early stages of prostate carcinogenesis. Cancer Res 2002 Jun 1;62(11):2999-3004
29. Cardo PP, Laura S, Del Beccaro R, Damiani G.Occurrence of 5 base guanine and
cytosine words defined by a computer method in six bacterial DNA sequences.Boll
Soc Ital Biol Sper. 1995 Nov-Dec;71(11-12):285-91.
30. Li J, Yen C, Liaw D, et al.PTEN, a Putative Protein Tyrosine Phosphatase Gene
Mutated in Human Brain, Breast, and Prostate Cancer.Science,
1997;275(5308):1943-1947
31. Kim MJ, Cardiff RD, Desai N et al Cooperativity of Nkx3.1 and Pten loss of
function in a mouse model of prostate carcinogenesis.. Proc Natl Acad Sci U S A 2002
Mar 5;99(5):2884-9
32. Bowen C, Bubendorf L, Voeller HJ, Slack R. Loss of NKX3.1 expression in
human prostate cancers correlates with tumor progression. Cancer Res 2000 Nov
1;60(21):6111-5
33. Xu LL, Srikantan V, Sesterhenn IA. Expression profile of an androgen regulated
prostate specific homeobox gene NKX3.1 in primary prostate cancer. J Urol 2000
Mar;163(3):972-9
34. Prescott JL,Blok L,Tindall DJ. Isolation and androgen regulation of the human
homeobox cDNA,NKX3.1.Prostate,1998;35(1):71-80