Clinical relevance of serum angiogenic activity in patients with transitional cell carcinoma of the bladder

Angiogenesis is essential for tumor growth and progression and is mediated by positive and negative regulators of vessel growth. Since angiogenic mediators found in patient serum have been postulated to reflect the angiogenic potential of a malignant tumor, we investigated the angiogenic activity in the serum of patients with transitional cell carcinoma (TCC). The data were correlated to tumor characteristics and the clinical course of the patients. Eighty-one patients with transitional cell carcinoma and 53 control persons were included in the study. Preoperative serum samples were collected and both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were quantified by ELISA. Additionally, the serum evoked proliferative activity on human umbilical vein endothelial cells (HUVEC) was evaluated. Data were compared to the clinical course of the patients. Serum of tumor patients significantly enhanced the proliferative capacity of HUVEC, compared to cells grown in standard culture medium (p = 0.0032), but not when compared to serum from control persons. Serum from patients with superficial TCC and well differentiated tumors induced a significantly higher angiogenic response (ANG(hi)) than serum from patients with poorly differentiated and invasive carcinomas (ANG(lo); p = 0.037). VEGF level of ANG(hi) serum was 384.22 +/- 247.76 pg/ml (n = 37) which significantly differed from mean VEGF level detected in ANG(lo) serum (247.72 +/- 211.93 pg/ml, n = 42; p = 0.019). Similarly, mean bFGF levels were 9.58 +/- 5.91 pg/ml in ANG(hi) serum versus 5.74 +/- 3.52 pg/ml) in ANG(lo) serum (p = 0.0043). A negative correlation was established between VEGF/bFGF serum concentration and patient prognosis. The experiments demonstrate a positive correlation between VEGF and bFGF serum level and endothelial proliferation in vitro. The inverse relationship between angiogenic activity and tumor stage might disclose information about angiogenesis and tumor progression in TCC.     

Prognostic factors of breast cancer

OBJECTIVES: Characterization of breast cancers by various tumour markers which are appropriate for the identification of high risk groups. Markers related to the metastasis cascade and tumour recurrence have been investigated. MATERIALS AND METHODS: RT-PCR was used to determine the expression of cytokeratin 20 in the bone marrow and sentinel lymph node of breast cancer patients (n=45). The expression of HER2, Cadherin E, Cyclin D, Bcl2 and Bax has been evaluated by Western blot (n=744 invasive ductal carcinomas and 117 invasive lobular carcinomas, 124 recurrent breast cancers). Mutations of p53, APC and beta Catenin genes were detected by PCR-SSCP method. RESULTS: Expression of cytokeratin 20 was found in 30% of the bone marrow samples indicating the presence of micrometastasis. The level of Cyclin D, HER2 and Bcl2 is elevated four-fold in the recurrent breast cancers. The metastasis of invasive ductal carcinomas is accompained by high frequency of p53 mutations (24%) and APC mutations (18%). The invasive lobular carcinomas could be characterized with low frequency of p53 mutation (3%), low level of Cadherin E and high level of catenin beta. CONCLUSIONS: Identification of micrometastasis can promote the development of therapeutic strategy. Evaluation of HER2 level and determination of p53 mutations contribute to the identification of high risk patients. Our results suggest that the progression of invasive ductal carcinomas depends on the APC mutations, while metastasis of invasive lobular carcinomas depends on beta catenin mutations.     

Radioimmunoscintigraphy using monoclonal antibodies to CEA, CA 19-9 and CA 125

131I labelled F (ab')2 fragments of monoclonal antibodies against CA 19-9 and CEA ("radioimmunococktail" IMACIS 1) were used in a prospective study (n = 60 patients) and in a retrospective study (n = 32 patients) for the detection of colorectal carcinomas (n = 67) and other gastrointestinal CEA/CA 19-9-producing tumors (n = 32). Sensitivity was 82% and specificity 90%. Immunoscintigraphy proved useful and complementary to CT scan and sonography, especially in the diagnosis of pelvic recurrences and intra-abdominal metastases. In addition, monoclonal antibody OC 125 (IMACIS 2) was used for the detection of ovarian carcinomas (n = 10) and other CA 125 producing tumors. Immunoscintigraphy was positive in all patients (n = 18) suggesting that this radioimmunological approach could be of use in the staging, therapeutic control and earlier diagnosis of recurrent epithelial ovarian carcinoma.     

中期因子在肿瘤发生和组织再生中的作用

中期因子(midkine,MK）是一种肝素结合性生长因子.在胚胎期,MK在组织中广泛分布.在成人体内其表达降低,仅局限于某些特定部位.MK受体种类繁多,信号通路复杂多样,这就决定了MK功能的多样化,它能促进很多种类细胞的生长、存活、分化和迁移,具有抗细胞凋亡的作用,不仅与肿瘤发生密切相关,而且在很多组织的发育形成及损伤后的修复再生过程均有参与.MK已成为恶性肿瘤在内的多种疾病治疗中颇具前景的分子靶点.本文中对MK的基因及蛋白结构、受体及相关信号通路、分子功能及作用机制等进行了全面的综述,并对其在肿瘤发生和发育与组织再生等方面的生物学功能及研究意义进行了深入的探讨.     

Mena, a new available marker in tumors of salivary glands?

Mena (mammalian Ena) is an actin regulatory protein involved in cell motility and adhesion. Based on its potential role in malignant transformation revealed in other organs, we analyzed the Mena expression in normal salivary glands (SG) and salivary tumors. Mena expression was determined in normal SG (n=10) and also benign (n=20) and malignant (n=35) lesions of SG. For the immunohistochemical staining we used the anti-Mena antibody. All normal SG and the benign lesions (10 pleomorphic adenomas, 10 Warthin's tumors) were Mena negative. Salivary duct carcinomas (n=5), carcinomas in pleomorphic adenoma (n=5), acinic cell carcinomas (n=5), squamous cell carcinomas (n=10) and high-grade mucoepidermoid carcinomas (n=2) were positive. The lymphomas (n=5) and low-grade mucoepidermoid carcinomas (n=1) were Mena negative. In one case the lymphoblastic cells stained positive for Mena. Some of the endothelial cells, in the peritumoral vessels, were Mena positive. To the best of our knowledge, this is the first study in the literature about Mena expression in salivary tumors. Our study suggests that Mena protein seems to play a role in malignant transformation and its intensity is correlated with the type and grade of tumor and also with vascular invasion. Its positivity in endothelial cells may suggest its potential role in tumor angiogenesis.     

Evaluation of MK filters for recovery of enteroviruses from tap water.

The MK filter is an electropositively charged filter that can be used to concentrate enteroviruses from large volumes (400 to 1,000 liters) of water. This filter is less expensive than the commonly used 1MDS electropositive filter. In this study, we compared the recovery of poliovirus 1 (PV1) and that of coxsackievirus B3 (CB3) from 378 liters of tap water, using both the MK and the 1MDS filters. Viruses were eluted from the filters with 3% beef extract buffered with 0.05 M glycine (pH 9.5) and reconcentrated via organic flocculation. At high virus inputs (approximately 10(6) PFU), the overall recovery (after elution and reconcentration) of PV1 and CB3 from tap water with the MK filter was less than that achieved with the 1MDS filter (P < 0.05). The recoveries of PV1 from tap water with the MK and 1MDS filters were 73.2% +/- 26% (n = 5 trials) and 90.2% +/- 5.9% (n = 5 trials), respectively. The recoveries of CB3 from tap water with the MK and 1MDS filters were 32.8% +/- 34.5% (n = 4 trials) and 95.8% +/- 12.0% (n = 4 trials), respectively. This study indicated that the MK filter consistently provided lower recovery, with wider variability, of PV1 and CB3 from tap water than the 1MDS filter.     

Mitogen‐activated protein kinase‐activated protein kinase 2 (MK2) in skeletal muscle atrophy and hypertrophy

Skeletal muscle is a highly plastic tissue. Overall muscle growth (hypertrophy) or muscle wasting (atrophy) results from alterations in intracellular signaling pathways with important regulatory steps occurring in the nucleus as well as in the cytoplasm. Previous studies have identified components of the Akt/mTor pathway as well as the p38 MAPK pathway as important for skeletal muscle hypertrophy and/or atrophy. The present study tests the hypothesis that MK2, a substrate of p38 which following phosphorylation, can be exported from the nucleus in a complex with p38, may be important for skeletal muscle growth. The expression of MK2 was examined in denervated mouse hind‐limb (atrophic) and hemidiaphragm (transiently hypertrophic) muscles. MK2 mRNA expression decreased after denervation in both atrophic (48% of innervated controls, P < 0.001) and hypertrophic muscle (34% of innervated controls, P < 0.01) but MK2 protein expression decreased only in atrophic muscle (32% of innervated controls, P < 0.01). The level of T205 phosphorylated MK2 increased after denervation in both atrophic (fourfold increase, P < 0.01) and hypertrophic muscles (almost sevenfold increase, P < 0.001) whereas the level of T317 phosphorylated MK2 (necessary for nuclear export) increased after denervation in hypertrophic muscle (nearly threefold increase, P < 0.001) but not in atrophic muscle. Logarithmically transformed relative changes in MK2 phosphorylated at T317 correlated well (r² = 0.7737) with relative changes in muscle weight. The results suggest a role for MK2 in the regulation of muscle mass, a role which, at least in part, may be related to determining the subcellular localization of p38 in muscle fibers. J. Cell. Physiol. 223: 194–201, 2010. © 2009 Wiley‐Liss, Inc.     

Flow-cytometric analysis of the DNA-content in paraffin-embedded tissue from colorectal carcinomas and its prognostic significance.

The nuclear DNA content of 163 colorectal carcinomas was determined by flow-cytometry (FCM) on formalin-fixed, paraffin-embedded tissue. DNA-aneuploidy was found in 97 cases (59.5%), in which no statistically significant correlations with sex, mean age, tumour stage (Dukes and pTNM) and tumour grade were noted. The frequency of aneuploidy was significantly higher in patients less than 70 years of age (p less than 0.01) and in tumours localized in the left colon and rectum (p less than 0.002), irrespective of their stage. The tumours in which different areas could be analysed (n = 80) showed a heterogeneous DNA-ploidy pattern in 18%. Comparison of the DNA content in primary tumours and in lymph node metastases (n = 49) showed a difference in DNA-ploidy in 38% of the DNA-aneuploid tumours, but in only 6% of the DNA-diploid carcinomas (p less than 0.02). DNA-aneuploid carcinomas tended to show a higher rate of local recurrence and were associated with an unfavourable prognosis (p = 0.04) in those patients in which complete resection of their tumours was possible (n = 72). The significantly higher mortality of patients with DNA-aneuploid carcinomas of stage pT3, as well as those with Dukes stage A and B tumours indicates that DNA-aneuploidy may be a stage-independent additional risk factor in colorectal cancer.     

Midkine, a cytokine that inhibits HIV infection by binding to the cell surface expressed nucleolin

The growth factor midkine （MK） is a cytokine that inhibits HIV infection in cell cultures in an autocrine and paracrine manner by blocking the attachment of HIV particles to permissive cells. MK mRNA is systematically expressed in adult peripheral blood lymphocytes from healthy donors, while its expression becomes markedly but transiently increased upon in vitro treatment of lymphocytes with IL-2 or IFN-7 and activation of T lymphocytes by PHA or through the engagement of the CD28 antigen. The binding of MK to cells occurs specifically at a high and a low affinity binding site. This low affinity-binding site is the cell-surface expressed nucleolin, which is implicated in the mechanism of the initial attachment of HIV particles to cells. Accordingly, the nucleolin-binding HB-19 pseudopeptide has no effect on the MK binding to the high affinity binding site, whereas it prevents the binding of MK to the low affinity binding site, thus suggesting the low affinity receptor of MK is the cell-surface-expressed nucleolin. Confocal immunofluorescence laser microscopy revealed the colocalization of MK and the cell-surface-expressed nucleolin at distinct spots. The use of various deletion constructs of nucleolin then indicates that the extreme C-terminal end of nucleolin, containing repeats of the amino acid motif RGG, as the domain that binds MK. The specific binding of MK to the surface nucleolin is independent of heparan sulfate and chondroitin sulfate proteoglycans. After binding to cells, MK enters cells by an active process in which nucleolin and lipid rafts appear to be implicated. The potent and the distinct anti-HIV action of MK along with its enhanced expression in lymphocytes by various physiological stimuli, point out that MK is a cytokine that could be involved in HIV pathogenesis.     

A new family of heparin-binding factors: strong conservation of midkine (MK) sequences between the human and the mouse

A retinoic acid responsive gene, MK, specifies for a heparin binding factor termed midkine (MK), which is the initial member of a new protein family involved in regulation of growth and differentiation. A cDNA clone of human MK was isolated from a fetal kidney cDNA library. Human MK mRNA was expressed in PA1 teratocarcinoma cells as well as in the kidney. Sequence analysis of the cDNA clone and of a part of the genomic clone yielded the predicted protein sequence of human MK. Human and mouse MK sequences are highly conserved: 87% of amino acids are identical and all amino acid changes are conservative except for an insertion. Comparison of MK and HB-GAM/pleiotrophin (another member of the family) from various species revealed sequences conserved in the family and those specific for each protein.     

Wee1 Inhibition by MK-1775 Leads to Tumor Inhibition and Enhances Efficacy of Gemcitabine in Human Sarcomas

Sarcomas are rare and heterogeneous mesenchymal tumors affecting both pediatric and adult populations with more than 70 recognized histologies. Doxorubicin and ifosfamide have been the main course of therapy for treatment of sarcomas; however, the response rate to these therapies is about 10–20% in metastatic setting. Toxicity with the drug combination is high, response rates remain low, and improvement in overall survival, especially in the metastatic disease, remains negligible and new agents are needed. Wee1 is a critical component of the G2/M cell cycle checkpoint control and mediates cell cycle arrest by regulating the phosphorylation of CDC2. Inhibition of Wee1 by MK1775 has been reported to enhance the cytotoxic effect of DNA damaging agents in different types of carcinomas. In this study we investigated the therapeutic efficacy of MK1775 in various sarcoma cell lines, patient-derived tumor explants ex vivo and in vivo both alone and in combination with gemcitabine, which is frequently used in the treatment of sarcomas. Our data demonstrate that MK1775 treatment as a single agent at clinically relevant concentrations leads to unscheduled entry into mitosis and initiation of apoptotic cell death in all sarcomas tested. Additionally, MK1775 significantly enhances the cytotoxic effect of gemcitabine in sarcoma cells lines with different p53 mutational status. In patient-derived bone and soft tissue sarcoma samples we showed that MK1775 alone and in combination with gemcitabine causes significant apoptotic cell death. Magnetic resonance imaging (MRI) and histopathologic studies showed that MK1775 induces significant cell death and terminal differentiation in a patient-derived xenograft mouse model of osteosarcoma in vivo. Our results together with the high safety profile of MK1775 strongly suggest that this drug can be used as a potential therapeutic agent in the treatment of both adult as well as pediatric sarcoma patients.     

Semiquantitative assessment of c-erbB-2 (HER-2) status in cytology specimens and tissue sections from breast carcinoma

OBJECTIVE: To determine whether various methods of fixation of surgical pathology specimens from breast carcinomas would influence the outcome of evaluation of the expression levels of c-erbB-2 (HER-2). For this, comparisons were made between (1) alcohol-fixed (95%) and air-dried smears from fresh surgical pathology specimens of breast carcinomas, and (2) formalin-fixed, paraffin-embedded tissue sections of the same specimens. STUDY DESIGN: Alcohol-fixed and air-dried smears or touch preparations were made from 30 fresh mastectomy/lumpectomy surgical pathology specimens from breast carcinomas. Immunohistochemistry was performed using the c-erbB-2 primary antibody against the extracellular domain of the c-erbB-2 gene product. Staining was simultaneously performed on formalin-fixed, paraffin-embedded tissue sections of the same specimens. A semiquantitative approach was used for evaluation of immunostaining by three independent investigators, and a consensus was reached. RESULTS: A total of 30 cases were reviewed. Tissue positivity was determined for c-erbB-2 in: 73% of alcohol-fixed specimens (n = 13 [3+] and n = 9 [2+]), 67% of air-dried smears (n = 9 [+3] and n = 11 [+2]) and 47% (n = 8 [+3]) and n = 6 [+2]) of formalin-fixed, paraffin-embedded tissue specimens. All formalin-fixed tissue specimens that were determined to positively express c-erbB-2 were also found to be positive on the alcohol-fixed smears. CONCLUSION: The incidence of c-erbB-2 expression in fresh cytologic material is significantly higher (P < .05) than in formalin-fixed, paraffin-embedded tissue. Alcohol-fixed smears demonstrate a slightly higher percentage of cell staining and stronger intensity of c-erbB-2 expression than the matched, air-dried smears. This is a sensitive and simple processing method that can be routinely applied in surgical pathology or fine needle aspiration biopsy specimens for the detection of c-erbB-2 (HER-2), with clinical implications.     

Midkine and pleiotrophin: two related proteins involved in development,survival, inflammation and tumorigenesis

Midkine (MK) and pleiotrophin (PTN) are low molecular weight proteins with closely related structures. They are mainly composed of two domains held by disulfide bridges, and there are three antiparallel beta-sheets in each domain. MK and PTN promote the growth, survival, and migration of various cells, and play roles in neurogenesis and epithelial mesenchymal interactions during organogenesis. A chondroitin sulfate proteoglycan, protein-tyrosine phosphatase zeta (PTPzeta), is a receptor for MK and PTN. The downstream signaling system includes ERK and PI3 kinase. MK binds to the chondroitin sulfate portion of PTPzeta with high affinity. Among the various chondroitin sulfate structures, the E unit, which has 4,6-disulfated N-acetylgalactosamine, provides the strongest binding site. The expression of MK and PTN is increased in various human tumors, making them promising as tumor markers and as targets for tumor therapy. MK and PTN expression also increases upon ischemic injury. MK enhances the migration of inflammatory cells, and is involved in neointima formation and renal injury following ischemia. MK is also interesting from the viewpoints of the treatment of neurodegenerative diseases, increasing the efficiency of in vitro development, and the prevention of HIV infection.     

HLA-G在生殖系统癌中的检测:免疫组织化学研究

为检测生殖系统癌有无HLA-G表达,采用免疫组化LDP法对223例生殖系统癌手术切除标本进行了鼠抗HLA-G单克隆抗体染色,观察了HLA-G在乳腺癌（n=100),卵巢癌（n=30),子宫颈癌（n=30),子宫内膜癌（n=40),前列腺癌（n=20)和睾丸胚胎癌（n=3)中的表达与分布。结果发现,除睾丸胚胎癌外,生殖系统其余部位癌标本可见到40-57.5%的HLA-G阳性表达,HLA-G阳性反应物在癌细胞内呈颗粒状及均质状,主要分布于细胞浆,结果提示,HLA-G表达可能是肿瘤生物学中的普遍现象,生殖系统癌细胞在发生和发展过程中其基因表达有可能出现反分化现象,开始表达HLA-G,从而使癌细胞产生免疫耐受,逃逸宿主的免疫监视。     

Immunohistochemical analysis of DNA 'mismatch-repair' enzyme human Mut-S-Homologon-2 in ovarian carcinomas

The human Mut-S-Homologon-2 (hMSH-2) gene product is a member of a highly conserved family of proteins involved in postreplication mismatch repair. We have analysed hMSH-2 expression in normal ovarian tissue (n=15) and ovarian carcinomas (n=40). hMSH-2 protein was investigated immunohistochemically on frozen sections using a highly sensitive streptavidin–peroxidase technique and a specific mouse monoclonal antibody (clone FE11). A hMSH-2-immunoreactivity score (hMSH-2-IRS) for semiquantitative analysis of hMSH-2 expression is presented. In normal ovarian tissue, we only found weak nuclear immunoreactivity for hMSH-2 in 60%, while the remaining 40% were hMSH-2 negative (mean hMSH-2-IRS: 0.73; SD: ±0.70). All ovarian carcinomas analysed revealed moderate to strong nuclear immunoreactivity (mean hMSH-2-IRS: 8.05; SD: ±3.65). hMSH-2 staining was heterogeneous, with visual differences between individual tumour cells. Expression of hMSH-2 protein was consistently and strongly upregulated in tumour cells of ovarian carcinomas as compared to normal ovarian tissue. No statistically significant correlation in comparing the labelling patterns for hMSH-2 with the labelling patterns for Ki-67 (mean percentage of Ki-67 positive tumour cells: 25.88%; SD: ±18.43) was observed in ovarian carcinomas. Furthermore, no statistical significant correlations between hMSH-2-IRS and histological grading (p=0.47), histological type of carcinoma (p=0.706) or FIGO-classification (p=0.054) were found. Our findings indicate that (a) hMSH-2 is expressed in normal human ovarian tissue, (b) expression of hMSH-2 is increased in ovarian carcinomas, (c) expression of hMSH-2 may be of importance for the genetic stability of ovarian carcinomas in vivo, (d) hMSH-2 mutations may not cause microsatellite instability in ovarian carcinomas, (e) hMSH-2 may contribute to mechanisms responsible for resistance to anticancer drugs.     

Immunohistochemical Analysis of DNA ‘mismatch-repair’ Enzyme Human Mut-S-Homologon-2 in Ovarian Carcinomas

The human Mut-S-Homologon-2 (hMSH-2) gene product is a member of a highly conserved family of proteins involved in postreplication mismatch repair. We have analysed hMSH-2 expression in normal ovarian tissue (n=15) and ovarian carcinomas (n=40). hMSH-2 protein was investigated immunohistochemically on frozen sections using a highly sensitive streptavidin–peroxidase technique and a specific mouse monoclonal antibody (clone FE11). A hMSH-2-immunoreactivity score (hMSH-2-IRS) for semiquantitative analysis of hMSH-2 expression is presented. In normal ovarian tissue, we only found weak nuclear immunoreactivity for hMSH-2 in 60%, while the remaining 40% were hMSH-2 negative (mean hMSH-2-IRS: 0.73; SD: ±0.70). All ovarian carcinomas analysed revealed moderate to strong nuclear immunoreactivity (mean hMSH-2-IRS: 8.05; SD: ±3.65). hMSH-2 staining was heterogeneous, with visual differences between individual tumour cells. Expression of hMSH-2 protein was consistently and strongly upregulated in tumour cells of ovarian carcinomas as compared to normal ovarian tissue. No statistically significant correlation in comparing the labelling patterns for hMSH-2 with the labelling patterns for Ki-67 (mean percentage of Ki-67 positive tumour cells: 25.88%; SD: ±18.43) was observed in ovarian carcinomas. Furthermore, no statistical significant correlations between hMSH-2-IRS and histological grading (p=0.47), histological type of carcinoma (p=0.706) or FIGO-classification (p=0.054) were found. Our findings indicate that (a) hMSH-2 is expressed in normal human ovarian tissue, (b) expression of hMSH-2 is increased in ovarian carcinomas, (c) expression of hMSH-2 may be of importance for the genetic stability of ovarian carcinomas in vivo, (d) hMSH-2 mutations may not cause microsatellite instability in ovarian carcinomas, (e) hMSH-2 may contribute to mechanisms responsible for resistance to anticancer drugs.     

siRNA targeting midkine inhibits gastric cancer cells growth and induces apoptosis involved caspase-3,8,9 activation and mitochondrial depolarization

Midkine (MK), a heparin-binding growth factor, is expressed highly in various malignant tumors, so it acts as attractive therapeutic target. In the present study, we used siRNA targeting MK to downregulate human MK expression in human gastric cancer cell line BGC823 and SGC7901 so as to determine the advantages of this anticancer therapeutic. The cell proliferation was evaluated by a WST-8 (4-[3-(2-methoxy-4-nitrophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1, 3-benzene disulfonate sodium salt) assay and colony formation assay. Apoptosis was determined by flow cytometer analysis and colorimetric assay. Our results showed that the BGC823 and SGC7901 cell growth were significantly inhibited by knockdown of MK gene. The loss of mitochondrial membrane potential, release of cytochrome c from the mitochondria into cytosol and increased activity of caspase-3, 8 and 9 occurred concomitantly with inhibition of MK gene. These results indicated that siRNA targeting MK gene can inhibit gastric cancer cells growth and induce apoptosis via mitochondrial depolarization and caspase-3 activation. MK siRNA may be a promising novel and potential therapeutic strategy for the treatment of gastric cancers.     

Antisense oligodeoxyribonucleotide as to the growth factor midkine suppresses neointima formation induced by balloon injury

Restenosis is the major clinical problem of angioplasty. We have previously shown that neointima formation is strikingly suppressed in midkine (MK)-deficient mice. Neointima formation is restored if MK protein is administrated to the deficient mice. MK is a heparin-binding growth factor and implicated in the migration of inflammatory cells and vascular smooth muscle cells. Consistently, the suppression of neointima formation in the deficient mice is accompanied by suppression of recruitment of inflammatory cells into the vascular wall. Here, we evaluated the potential of MK antisense oligodeoxyribonucleotide (ODN) for the prevention of restenosis. We cloned the cDNA of rabbit MK, which showed a strongly conserved sequence in mammals. The balloon injury induced MK expression, with the maximum level occurring 7-14 days after angioplasty, in the rabbit carotid artery. Two antisense ODNs suppressed the production of MK in a rabbit kidney cell line, RK13 cells, one of which was then transfected into the arterial wall by means of lipofection immediately after balloon treatment. The antisense ODN suppressed MK induction in vivo and consequently suppressed neointima formation to 60% of the control level. These results suggest that MK is a candidate molecular target for the therapy for vascular restenosis.