Alu基因定量检测用于胃癌转移模型评估的研究

目的研究人胃癌转移裸鼠模型中人Alu基因的表达水平与组织脏器中胃癌转移程度的相关性,探索建立胃癌转移模型早期评估的分子生物学方法。方法分别以人胃癌细胞SGC-7901、MKN45和正常胃黏膜细胞GES1基因组DNA为模板构建标准质粒,通过实时荧光定量PCR检测不同比例胃癌细胞SGC-7901中Alu基因的表达,获取相关性曲线;选取胃癌细胞SGC-7901和MKN45,通过裸鼠皮下接种的方式构建人胃癌细胞异种移植转移模型,实时荧光定量PCR方法检测模型鼠肝、脾、肺、肾和皮下肿瘤组织中的人Alu基因表达,获得Alu基因的表达与各器官组织中肿瘤转移程度的相关性曲线;将临床胃癌患者新鲜肿瘤标本皮下接种裸鼠构建异种移植模型,进一步验证模型鼠各组织中人Alu基因的表达与器官中肿瘤转移程度的相关性。结果胃癌细胞SGC-7901的含量与其Alu基因的Ct值呈负相关(R2=0.9239);人胃癌细胞异种移植(CDX)裸鼠转移模型中,人Alu基因的表达在皮下肿瘤中处于较高水平,在肺转移瘤和肝转移瘤中的表达则介于正常裸鼠与皮下肿瘤之间,与组织病理学检查结果相符;胃癌病人肿瘤异种移植(PDX)模型中,已确定发生转移的脏器中虽未形成肉眼可见的转移灶,但其人Alu基因的表达(Ct值17.86)与正常裸鼠(Ct值22.18)差异显著(P 0.05);而对于肉眼可见的转移灶,其人Alu基因的表达(Ct值14.29)则差异极显著(P 0.01)。结论人胃癌裸鼠转移模型中,人Alu基因的表达与胃癌转移程度呈正相关,Alu基因表达越高,则该组织中转移的肿瘤细胞就越多,形成的转移灶越明显。     

甲醛致大鼠鼻腔癌与K-ras癌基因活化相关

为探讨甲醛致大鼠鼻腔癌的分子机制,对甲醛诱发的大鼠鼻腔癌细胞系FAT7中的转化序列进行检测.采用的实验方法,包括肿瘤细胞DNA与选择标志基因(neo)共转染、裸鼠成瘤性分析、Southern杂交、聚合酶链反应(PCR)和序列分析等.结果发现:在第二轮裸鼠肿瘤DNA中含有大鼠源性的K-ras基因序列,而无大鼠源性的H-ras、N-ras和p53基因序列.这表明甲醛诱发的大鼠鼻腔癌细胞系FAT7中所含的转化序列与H-ras、N-ras及p53基因无关,K-ras癌基因的活化可能参与甲醛致大鼠鼻腔癌.     

沉默Dnmt1基因表达诱导大白鼠骨髓间充质干细胞向心肌样细胞分化

骨髓间充质干细胞(MSCs)具有向心肌样细胞分化的潜能.本室前期研究发现,MSCs在体外经DNA甲基转移酶(Dnmt)抑制剂5-氮胞苷诱导可分化为心肌样细胞.本研究证明,沉默DNA甲基化转移酶1（Dnmt1）基因表达,可诱导大鼠MSCs向心肌样细胞分化.本文采用表达Dnmt1 siRNA 慢病毒感染MSCs,沉默Dnmt1表达.DNA甲基化分析显示,随着沉默Dnmt1时间延长（7-28 d）,Gata-4基因上游DNA调控序列的CpG甲基化水平明显降低,而Gata-4 mRNA的转录水平明显上调,说明敲减Dnmt1表达导致Gata-4基因激活.蛋白质印迹和/或免疫细胞化学揭示,与对照组比较,心肌相关基因MHC 和cTnT表达上调, 而骨髓干细胞标志物CD90和CD29随转染时间延长表达下调.同时,实时定量PCR显示,心肌早期发育调控基因Nkx2.5 mRNA水平与Gata-4 mRNA相同,随表达Dnmt1 siRNA的慢病毒感染而上调.上述结果提示,敲减Dnmt1可降低心肌发育调控基因Gata-4启动子CpG岛的甲基化水平,上调Gata-4基因的表达,诱导骨髓间充质干细胞向心肌样分化.     

活体荧光成像对裸鼠肝癌细胞系MHCC97-H原位移植模型的动态量化分析

目的:利用生物自发光的裸鼠肝癌原位移植模型,以活体荧光成像技术对肝癌的生长和转移情况进行动态、量化分析.方法:将稳定转染了荧光素酶(luciferase)基因的人肝癌细胞株MHCC97-H-LUC细胞,移植至裸鼠肝脏包膜下,每周利用活体荧光成像系统对裸鼠体内移植瘤的生长部位和范围进行成像,测量肿瘤细胞生物发光量,动态观察肝癌细胞在裸鼠体内的肿瘤数量、生长速度和转移情况.结果:建立可稳定表达荧光素酶的人肝癌细胞株MHCC97-H-LUC并用于进行生物自发光的裸鼠原位移植模型;利用活体荧光成像系统对裸鼠体内的移植瘤成像,见发光部位由肝脏向腹腔扩散,发光量随时间呈指数级增长;病理学观察证实肿瘤细胞长.结论:利用活体荧光成像技术的动态量化分析可灵敏、准确地监测裸鼠肝癌原位移植模型中肿瘤细胞的生长及转移情况,为肿瘤发生、生长、转移机制及对抗肿瘤生长和转移的体内研究提供了科学的量化手段.     

干扰OVA66基因表达对移植瘤生物学功能的影响

目的探讨干扰OVA66基因表达对移植瘤细胞生物学功能的影响。方法采用脂质体法,以重组的pSUPER-shRNA-OVA66和空载体转染HeLa细胞获得稳定表达细胞株,经RT-PCR和Western blot鉴定OVA66基因的表达。将两组细胞接种于BALB／cnu／nu裸鼠的前肢腋下,连续观察干扰OVA66表达对肿瘤的生长影响。并于接种4周后,应用RT-PCR,免疫组化、免疫荧光等方法检测移植瘤细胞中OVA66的蛋白表达。组织病理分析肿瘤细胞生长和转移的特征。结果经检测pSUPER-shRNA-OVA66能有效抑制目的基因的表达。比较两组荷瘤小鼠中肿瘤的生长曲线发现,OVA66实验组的肿瘤生长速度明显低于对照组,并且肿瘤细胞体内转移和浸润能力显著降低。结论干扰OVA66基因和蛋白表达,可以抑制肿瘤细胞的生长,浸润和侵袭能力。     

沉默Dnmt1基因表达诱导大鼠骨髓间充质干细胞向心肌样细胞分化

骨髓间充质干细胞(MSCs)具有向心肌样细胞分化的潜能.本室前期研究发现,MSCs在体外经DNA甲基转移酶(Dnmt)抑制剂5-氮胞苷诱导可分化为心肌样细胞.本研究证明,沉默DNA甲基化转移酶1(Dnmt1)基因表达,可诱导大鼠MSCs向心肌样细胞分化.本文采用表达Dnmt1 siRNA慢病毒感染MSCs,沉默Dnmt1表达.DNA甲基化分析显示,随着沉默Dnmt1时间延长(7-28 d),Gata-4基因上游DNA调控序列的Cp G甲基化水平明显降低,而Gata-4 mRNA的转录水平明显上调,说明敲减Dnmt1表达导致Gata-4基因激活.蛋白质印迹和/或免疫细胞化学揭示,与对照组比较,心肌相关基因MHC和c Tn T表达上调,而骨髓干细胞标志物CD90和CD29随转染时间延长表达下调.同时,实时定量PCR显示,心肌早期发育调控基因Nkx2.5 mRNA水平与Gata-4 mRNA相同,随表达Dnmt1 siRNA的慢病毒感染而上调.上述结果提示,敲减Dnmt1可降低心肌发育调控基因Gata-4启动子Cp G岛的甲基化水平,上调Gata-4基因的表达,诱导骨髓间充质干细胞向心肌样分化.     

化学致癌物DNP致人胚鼻咽上皮细胞转化相关基因的鉴定

为了探讨DNP致癌的分子机理,鉴定出化学致癌物二亚硝基哌嗪(DNP)致人胚鼻咽上皮细胞转化相关的基因及其活化方式．采用DNA共转染、裸鼠致瘤性试验、Southern杂交、PCR测序和序列同源性比较分析等,对DNP转化的人胚鼻咽上皮细胞株HENE—DNP进行研究．经过两轮DNA共转染和裸鼠致瘤性实验．Southern杂交表明,裸鼠肿瘤DNA中均含有人特异性高度重复序列Alu．用人Ha-ras、Ki-ras及N-ras癌基因特异性引物对裸鼠肿瘤DNA进行PCR扩增,仅能扩增出人Ha-ras基因相应的片段．Southem杂交进一步证实．裸鼠肿瘤DNA中存在与人Ha-ras基因片段大小一致的杂交带．RT-PCR产物测序,并将测序结果与GenBank进行序列同源性比较分析,发现裸鼠肿瘤中人Ha-ras基因cDNA第26位密码子第2位碱基发生了T→C的转换,编码的氨基酸由亮氨酸相应地变换成丝氨酸．化学致癌物DNP致人胚鼻咽上皮细胞转化相关的基因是Ha-ras,原癌基因c-Ha-ras激活可能是DNP转化人胚鼻咽上皮细胞的分子机制之一。     

CYB5D2对乳腺癌皮下移植瘤模型大鼠肿瘤生长的影响

[目的]研究CYB5D2对乳腺癌皮下移植瘤模型大鼠肿瘤生长的影响。[方法]通过乳腺癌MCF-7细胞系建立乳腺癌裸鼠皮下移植瘤动物模型。将含有CYB5D2表达的质粒稳定转染MCF-7细胞,多点注射,将稳定转染的细胞注入裸鼠皮下,作为观察组,同时设置shRNA-CYB5D2阴性质粒为阴性对照组,PBS为空白对照组。测量各组大鼠肿瘤体积及质量;裸鼠转移瘤模型建立成功后处死小鼠,qRT-CPR法检测肿瘤组织内CYB5D2 mRNA表达水平;Western Blot法检测各组裸鼠转移瘤组织内上皮细胞间质转化(EMT)标志表白表达情况,酶联免疫吸附法检测裸鼠转移瘤细胞上清液中MMP-2及MMP-9水平。[结果]观察组转移瘤平均体积及质量显著低于阴性组与空白组(P<0.05),阴性组与空白组裸鼠转移瘤体积及质量无明显差异(P>0.05)。提取试验小鼠肿瘤组织总RNA,qRT-CPR法检测提示观察组肿瘤组织内CYB5D2 mRNA表达量显著高于阴性组及空白对照组(P<0.05),而阴性组与空白组间差异无显著性差异(P>0.05);Western Blot法检测结果显示,观察组转移瘤组织内E-cadherin、β-catenin蛋白表达水平显著高于与阴性组及空白组(P<0.05),而N-cadherin及Snail蛋白表达显著低于与阴性组及空白组(P<0.05)。阴性组与空白组转移瘤组织内E-cadherin、β-catenin、N-cadherin及Snail蛋白表达无显著性差异(P>0.05);观察组裸鼠转移瘤细胞上清液中MMP-2及MMP-9水平显著低于与阴性组及空白组(P<0.05),而阴性组与对照组MMP-2及MMP-9水平无显著性差异(P>0.05)。[结论]上调CYB5D2基因可有效抑制乳腺癌皮下移植模型大鼠瘤体生长,推测上调CYB5D2基因可能通过下调N-cadherin、Snail、MMP2及MMP9,上调E-cadherin、β-catenin,逆转EMT,发挥抗肿瘤功效。     

裸鼠肿瘤动物模型VEGF受体表达及其意义

目的　通过免疫组织化学染色了解flt 1与flk 1 KDR(VEGF的两个高亲和受体 )在人肿瘤细胞皮下接种肿瘤动物模型的血管内皮细胞与肿瘤细胞中的表达。方法　取荷瘤裸鼠皮下接种瘤块 ,漂洗、固定、石蜡连续切片 ,进行两种受体相应免疫组化检测。结果　在 13种荷瘤裸鼠血管内皮细胞及肿瘤细胞中flt 1的阳性率大部分为强阳性或中阳性 ,而只有在荷人胃腺癌MKN 4 5裸鼠的肿瘤细胞中flt 1的阳性率为弱阳性 ,在荷人卵巢癌SKOv3裸鼠的肿瘤细胞中flt 1的表达为阴性。相比较而言 ,在 13种荷瘤裸鼠血管内皮细胞及肿瘤细胞中KDR的阳性率大部分为中阳性或弱阳性 ,并且在荷人肝癌SMMC 772 1裸鼠 ,荷人胃腺癌SPC A1裸鼠 ,荷人高转移肝癌移植瘤裸鼠 ,荷人卵巢癌SKOv3裸鼠的肿瘤细胞中 ,荷人宫颈癌移植瘤裸鼠和荷人胃腺癌MKN 4 5裸鼠的肿瘤细胞中 ,KDR表达为阴性。结论　VEGF受体共同表达于肿瘤血管内皮细胞与肿瘤细胞 ,提示了VEGF与VEGF受体结合作用在肿瘤演化中的重要性 ,为靶向于VEGF受体的基因治疗策略选择裸鼠动物模型提供了参考依据     

Tet调控STGC3基因表达的CNE2细胞系裸鼠成瘤实验性研究

STGC3基因是一个新近克隆的肿瘤相关基因,前期的体外实验研究结果表明,STGC3基因在CNE2鼻咽癌细胞系高表达,可明显抑制CNE2的生长增殖.采用Tet/pTRE-STGC3/CNE2细胞系接种于裸鼠皮下,以强力霉素(Dox)诱导STGC3基因高表达,观测STGC3基因高表达对CNE2裸鼠体内成瘤的影响,并探讨其可能作用机制.运用RT-PCR、蛋白质印迹及免疫组织化学方法,分别从mRNA和蛋白质水平,分析瘤组织中STGC3基因的表达;用流式细胞仪检测移植瘤组织内肿瘤细胞的凋亡情况;用免疫组织化学方法,检测移植瘤组织凋亡相关蛋白Bcl-2和Bax的表达.研究结果显示,STGC3蛋白表达主要定位于细胞核内,Dox诱导STGC3基因在Tet/pTRE-STGC3/CNE2细胞系高表达,Tet/pTRE-STGC3/CNE2细胞系裸鼠体内成瘤受到明显抑制,与对照组比较,移植瘤成瘤时间晚、生长慢、肿块小、细胞凋亡率高,Bax蛋白表达增强,Bcl-2蛋白表达减少,差异有显著性意义(P<0.01).此体内实验研究结果与前期体外实验结果一致,进一步证明STGC3基因对肿瘤细胞生长具有抑制作用.     

端粒酶RNA和端粒酶活性在人生殖道癌细胞株中的表达

本文采用反转录套式PCR(nested RT-PCR)和PCR端粒重复扩增(TRAP)方法分别检测了5种人生殖道癌细胞株端粒酶RNA(hTR)基因及端粒酶活性的表达。结果表明,宫颈癌HeLa和SiHa细胞株,绒毛膜癌JAR和BeWo细胞株及卵巢癌OCCI细胞株hTR及端粒酶活性均呈强阳性。但正常卵巢、宫颈和胎盘组织hTR和端粒酶呈阴性或弱阳性。提示反转录套式PCR和端粒重复扩增法可以简便而有效地检测端粒酶RNA及端粒酶活性。端粒酶的激活与肿瘤细胞增殖密切相关,并可能成为一项具有临床价值的肿瘤标志物。     

Identification of an autoregulatory feedback pathway involving interleukin-1alpha in induction of constitutive NF-kappaB activation in pancreatic cancer cells

We previously reported that NF-kappaB is constitutively activated in most human pancreatic cancer tissues and cell lines but not in normal pancreatic tissues and immortalized pancreatic ductal epithelial cells. IkappaBalphaM-mediated inhibition of constitutive NF-kappaB activity in human pancreatic cancer cells suppressed tumorigenesis and liver metastasis in an orthotopic nude mouse model, suggesting that constitutive NF-kappaB activation plays an important role in pancreatic tumor progression and metastasis. However, the underlying mechanism by which NF-kappaB is activated in pancreatic cancer remains to be elucidated. In this study, we found that an autocrine mechanism accounts for the constitutive activation of NF-kappaB in metastatic human pancreatic cancer cell lines. Further investigation showed that interleukin-1alpha was the primary cytokine secreted by these cells that activates NF-kappaB. Neutralization of interleukin-1alpha activity suppressed the constitutive activation of NF-kappaB and the expression of its downstream target gene, urokinase-type plasminogen activator, in metastatic pancreatic cancer cell lines. Our results demonstrate that regulation of interleukin-1alpha expression is primarily dependent on AP-1 activity, which is in part induced by signaling pathways that are epidermal growth factor receptor-dependent and -independent. In conclusion, our findings suggest a possible mechanism for the constitutive activation of NF-kappaB in metastatic human pancreatic cancer cells and a possible missing mechanistic link between inflammation and cancer.     

nm23-H1-GFP融合蛋白在人肺癌细胞株中的表达及其对肿瘤细胞体外侵袭能力的影响

研究 nm2 3- H1在肿瘤细胞中的定位及其对肿瘤细胞体外侵袭能力的影响 .用 RT- PCR方法检测人高和低转移肺巨细胞癌细胞株 95 D和 95 C中 nm2 3- H1的表达 ;利用分子克隆技术构建nm2 3- H1 -绿色荧光蛋白 ( GFP)融合基因表达质粒 ( p NM2 3- GFP) ,经脂质体转染将此质粒导入95 D和 95 C细胞中 ,筛选高荧光强度的克隆 ,用 Boyden小室模型检测其体外侵袭能力的变化 .结果显示 nm2 3- H1在 95 C细胞中的表达比 95 D高 .95 D细胞中表达的 nm2 3- H1 c DNA未发生突变 .表达的 nm2 3- H1 - GFP融合蛋白位于细胞的胞浆近胞膜处 .转染 p NM2 3- GFP质粒的 95 D和 95 C细胞体外侵袭能力明显比对照组低 .这些提示 nm2 3- H1高表达能明显降低肿瘤细胞体外侵袭能力 .     

A transgenic red fluorescent protein‐expressing nude mouse for color‐coded imaging of the tumor microenvironment

The tumor microenvironment (TME) is critical for tumor growth and progression. We have previously developed color‐coded imaging of the TME using a green fluorescent protein (GFP) transgenic nude mouse as a host. However, most donor sources of cell types appropriate for study in the TME are from mice expressing GFP. Therefore, a nude mouse expressing red fluorescent protein (RFP) would be an appropriate host for transplantation of GFP‐expressing stromal cells as well as double‐labeled cancer cells expressing GFP in the nucleus and RFP in the cytoplasm, thereby creating a three‐color imaging model of the TME. The RFP nude mouse was obtained by crossing non‐transgenic nude mice with the transgenic C57/B6 mouse in which the β‐actin promoter drives RFP (DsRed2) expression in essentially all tissues. In crosses between nu/nu RFP male mice and nu/+ RFP female mice, the embryos fluoresced red. Approximately 50% of the offspring of these mice were RFP nude mice. In the RFP nude mouse, the organs all brightly expressed RFP, including the heart, lungs, spleen, pancreas, esophagus, stomach, duodenum, the male and female reproductive systems; brain and spinal cord; and the circulatory system, including the heart, and major arteries and veins. The skinned skeleton highly expressed RFP. The bone marrow and spleen cells were also RFP positive. GFP‐expressing human cancer cell lines, including HCT‐116‐GFP colon cancer and MDA‐MB‐435‐GFP breast cancer were orthotopically transplanted to the transgenic RFP nude mice. These human tumors grew extensively in the transgenic RFP nude mouse. Dual‐color fluorescence imaging enabled visualization of human tumor–host interaction. The RFP nude mouse model should greatly expand our knowledge of the TME. J. Cell. Biochem. 106: 279–284, 2009. © 2008 Wiley‐Liss, Inc.     

Isolation and characterization of the major form of human MUC18 cDNA gene and correlation of MUC18 over-expression in prostate cancer cell lines and tissues with malignant progression.

Ectopical expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the development and malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. We cloned and characterized the human MUC18 (huMUC18) cDNA gene from three human prostate cancer cell lines and three human melanoma cell lines. The cDNA sequences from the six human cancer cell lines were identical except differences in one to five nucleotides. The deduced amino acid sequences of the longest ORF were 646 amino acids that were identical in these cDNAs except for one to three amino acid residues. The amino acid sequences of all our huMUC18 cDNA genes are similar to that cloned by other group (GenBank access #M28882) except differences in the same seven amino acids. We conclude that huMUC18 cDNA gene reported here represents the gene product from a major allele. The MUC18 mRNA and protein was expressed in three metastatic prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one non-metastatic prostate cancer cell line (LNCaP.FGC). The expression of huMUC18 in these four cell lines is positively related to their extent of in vitro motility and invasiveness and in vivo metastasis in nude mice. HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from cultured primary normal prostatic epithelial cells and the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas, and in cells of a perineural invasion, a lymph node, and a lung metastases compared to that in normal or benign hyperplastic epithelium (BPH). We therefore conclude that MUC18 expression is increased during prostate cancer initiation (high grade PIN) and progression to carcinoma, and in metastatic cell lines and metastatic carcinoma. Increased expression of MUC18 is implicated to play an important role in developing and malignant progression of human prostate cancer. Furthermore, the lacking of predominant cytoplasmic membrane expression of MUC18 appeared to correlate with malignant progression of prostate cancer.     

The human homolog of the rodent immediate early response genes, PC4 and TIS7, resides in the lung cancer tumor suppressor gene region on chromosome 3p21

Recently, human chromosome band 3p21.3 was shown to undergo overlapping homozygous deletions in several small cell lung cancer lines further defining a putative tumor suppressor gene(s) region. We report the cloning and mutational analysis of a novel human gene, SKMc15, from the commonly homozygously deleted region in three small cell lung cancer lines (NCI-H1450, NCI-H740, GLC20). It has 11 exons ranging in size from 50 to 541 bp with an open reading frame of 442 amino acids. The gene covers 7 to 10 kb of genomic DNA; the message of 1.8 to 2 kb is expressed in all analyzed fetal and adult human and mouse tissues including heart, brain, placenta, lung liver, skeletal muscle, kidney, testis and pancreas and in small cell and non-small cell cancer lines. The intron/exon boundaries were used to analyze the gene for mutations by exon PCR-SSCP sequencing in 60 small cell lung cancer cell lines. No loss-of-function mutations were detected. The cDNA sequence has high homology, 75% at the protein level, to the rat early response gene PC4 and its murine homolog TIS7. In addition, the known partial sequence of the putative mouse interferon β2 (64 amino acids) gene is highly conserved in PC4/TIS7 (94%) and in SKMc15 (83%) at the amino acid level. The sequence TAAAT, which is thought to be involved in mRNA degradation, is present in the 3′ UTR of SKMc15 and in the 3′ UTR of PC4 and TIS7 genes. Received: 28 August 1996 / Revised: 18 October 1996     

Periostin Contributes to the Acquisition of Multipotent Stem Cell-Like Properties in Human Mammary Epithelial Cells and Breast Cancer Cells

Periostin (POSTN), a recently characterised matricellular protein, is frequently dysregulated in various malignant cancers and promotes tumor metastatic growth. POSTN plays a critical role in the crosstalk between murine breast cancer stem cells (CSCs) and their niche to permit metastatic colonization. However, whether pro-metastatic capability of POSTN is associated with multipotent potentials of mesenchymal stem cells (MSCs) has not been documented. Here we demonstrate that POSTN promotes a stem cell-like trait and a mesenchymal phenotype in human mammary epithelial cells and breast cancer cells. Interestingly, ectopic overexpression of POSTN or recombinant POSTN treatment can induce human mammary epithelial cells and breast cancer cells differentiation into multiple cell lineages that recapitulate part of the multilineage differentiation potentials of MSCs. Moreover, POSTN is highly expressed in bone marrow-derived MSCs and their derived adipocytes, chondrocytes, and osteoblasts in vitro. Furthermore, POSTN promotes the growth of xenograft tumors in vivo. POSTN-overexpressing human mammary epithelial cells enhance breast tumor growth and metastasis. These data thus provide evidence of a new role for POSTN in mammary epithelial neoplasia and metastasis, suggesting that epithelial cancer cells might acquire CSC-like traits and a mesenchymal phenotype, as well as the multipotent potentials of MSCs to promote tumorigenesis and metastasis. Therefore, targeting POSTN and other extracellular matrix components of tumor microenvironment may help to develop new therapeutical strategies to inhibit tumor metastasis.