Reduced expression of nm23-H1, but not of nm23-H2, is concordant with the frequency of lymph-node metastasis of human breast cancer

nm23-H1 expression in nasopharyngeal carcinoma: correlation with clinical outcome

The expression levels of nm23-H1 mRNA and its protein in human nasopharyngeal carcinoma (NPC) were detected to clarify the relationship between nm23-H1 and metastasis and prognosis of patients with NPC. nm23-H1 mRNA expression in fresh tissues from 78 patients with NPC was investigated by in situ hybridization and RT-PCR. Routine labeling streptavidin-biotin immuno-histochemistry with the nm23-H1 murine monoclonal antibody was employed to study the expression of nm23-H1 protein in paraffin-embedded specimens from 231 patients with NPC treated in our hospital. The clinical pathologic data and results of follow-up were collected. Comparisons between expression of nm23-H1 protein or mRNA and clinical outcome were performed using the chi2 test. Multivariate prognostic analyses were performed by the Cox regression model. We found that nm23-H1-negative tumors were associated with a higher incidence of lymph-node metastasis (84.2%) than nm23-H1-positive ones (32.8%, p < 0.01). The distant metastasis and loco-regional recurrence rates in the nm23-H1-negative group were 55.8% and 31.68%, respectively but only 17.2% and 11.5%, respectively, in the nm23-H1-positive group (p < 0.01). A significant association was found between expression of nm23-H1 protein and prognosis (p < 0.01). Expression of nm23-H1 protein indicated favorable prognosis, suggesting that the absence of nm23-H1 protein expression was significantly associated with lymph-node metastasis, recurrence and distant metastasis in NPC. Expression of the nm23-H1 gene may be valuable for assessing the prognosis of NPC.

Expression of nm23 in gastric carcinoma: association with tumor progression and poor prognosis

BACKGROUND

Expression of nm23 has been shown to be inversely correlated with the metastatic potential of several human cancers. In the current study, the expression and prognostic impact of nm23 was immunohistochemically studied in 413 curatively resected gastric carcinomas.

METHODS

Tumor sections of the 413 gastric carcinomas were stained with a polyclonal antibody that was raised against the nm23-H1/NDP kinase A, which is identical to the nm23-H1 gene product.

RESULTS

Expression of nm23 was detected in 84.5% (n = 349) of all tumors, in the majority of cases (71.2%) causing a homogeneous staining reaction in more than 75% of tumor cells. Expression of nm23 was positively correlated with the intestinal type of tumor, according to the Lauren classification and advanced pT categories, and was also correlated with the presence of blood and lymphatic vessel invasion. In contrast, no correlation could be demonstrated between nm23 expression and lymph node involvement. As shown in univariate analysis, patients with nm23 positive tumors, especially those with nm23 positive diffuse-type carcinomas, had significantly shorter overall survival than patients with nm23 negative tumors (P = 0.03 and P = 0.0065, respectively). However, in a multivariate analysis that included the prognostic parameters pT category, pN category, and blood and lymphatic vessel invasion, this prognostic impact was not maintained.

CONCLUSIONS

In contrast to results for breast and colorectal carcinomas, our results for 413 gastric carcinomas showed that expression of the designated metastasis suppressor gene nm23 is correlated with aggressive tumor growth and poor prognosis but is not an independent prognostic marker.

nm23-H1 protein immunoreactivity in intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix

Differences in the immunohistochemical expression of the 17 kDa protein encoded by the human nm23-H1 gene were studied in premalignant lesions and invasive squamous cell carcinoma (SCC) (N = 8) of the cervix using routine streptavidin-biotin immunohistochemistry and a polyclonal antibody to the nm23-H1 protein. The premalignant lesions were koilocytic atypia due to wart virus infection (N = 5), low-grade cervical intraepithelial neoplasia (CIN) (N = 7) and high-grade CIN (N = 7). The carcinomas were either moderately (N = 3) or poorly differentiated (N = 5). The non-neoplastic controls were normal squamous epithelium from cases with uterine prolapse (N = 7) and normal squamous epithelium not affected by the infective or neoplastic areas of some of the cases with wart virus infection (N = 2) and carcinoma (N = 2). Moderate to strong cytoplasmic and, occasionally, nuclear immunostaining for the nm23-H1 protein was seen in all cells above the basal layer of the normal squamous epithelium. However, most of the cervical SCC show a relative reduction in nm23-H1 immunoreactivity (7/8 cases; 88%). This difference in nm23-H1 expression was statistically significant (P = 0.0006; Chi-squared test with continuity correction). All of the cases with wart virus infection (N = 5; 100%) displayed moderately strong nm23-H1 immunostaining throughout the squamous epithelium except for the basal layer where no staining was observed. The cases that had low-grade squamous dysplasia of the cervix (CIN I-II) (N = 7; 100%) also displayed moderate to strong nm23-H1 immunoreactivity in the epithelium except for the basal layer (CIN I) or the lower two-thirds of the epithelium (CIN II). nm23-H1 Immunoreactivity was either absent or was significantly reduced in all of the high-grade CIN (CIN III) cases (N = 7; 100%) in which only the non-dysplastic superficial third of the squamous epithelium displayed nm23-H1 immunolabeling. The difference in nm23-H1 expression between low-grade and high-grade CIN cases was statistically significant (P = 0.0013; Chi-squared test with continuity correction). Similarly, the difference between low-grade CIN and SCC cases in the expression of nm23-H1 was also significant (P = 0.0041; Chi-squared test with continuity correction). However, no statistically significant difference in nm23-H1 immunoreactivity was found between cases of high-grade CIN and SCC. In conclusion, nm23-H1 protein immunoreactivity is reduced in high-grade CIN and cervical SCC but not in low-grade CIN. These findings suggest that reduced expression of the protein may be important early in the sequential development of cervical squamous neoplasia.

Numerical aberrations of chromosome 17 in interphase cell nuclei of breast carcinoma cells: lack of correlation with abnormal expression of p53, neu and nm23 protein

The genes for p53, neu (c-erbB-2) and nm23 are all located on chromosome 17. Abnormal expression of their protein products is an important prognostic parameter. The aim of this study was to investigate if numerical aberrations of chromosome 17 are reflected in the expression of these markers. The immunohistochemical expression was analysed on histological specimens from 33 breast carcinomas. In situ hybridization (ISH) was performed on interphase cell nuclei in air-dried fine-needle aspirates from the same cases using a digoxigenin-labelled alpha-satellite probe for chromosome 17. ISH for chromosome 6, 7 and 12 was used additionally to give an estimate of ploidy. Of the carcinomas 76% were aneuploid, and numerical abnormalities of chromosome 17 were found in 34%. Abnormal p53 protein was expressed in 15% (five cases). All of these were aneuploid, but only one of them revealed aneusomy of chromosome 17. Neu overexpression was found in 18% of the tumours (six cases). Five of these were aneuploid, whereas two were aneusome for chromosome 17. Four cancers showed full (normal) expression of nm23 protein, whereas 29 had reduced expression. Reduced expression was found in 23 of 25 aneuploid tumours. Numerical aberrations of chromosome 17 were found equally in carcinomas with reduced and full nm23 protein expression. Abnormal numbers of chromosome 17 seem only to have a minor impact on these markers and are not reflected significantly in their expression.

Glyceraldehyde-3-phosphate dehydrogenase and Nm23-H1/nucleoside diphosphate kinase A. Two old enzymes combine for the novel Nm23 protein phosphotransferase function

We have recently discovered an alternative function of the putative metastasis suppressor protein Nm23, which is identical to nucleoside diphosphate kinase, as a protein phosphotransferase in vitro. While purified native Nm23 protein did not phosphorylate other proteins, we could purify a Nm23-associated protein that activates the protein phosphotransferase function; it was identified as a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) isoenzyme. Co-expression and purification of (His)6-tagged GAPDH in combination with either Nm23-H1 or Nm23-H2 in baculovirus-infected Sf9 cells showed that only Nm23-H1, but not Nm23-H2, forms a stable complex with GAPDH. Protein phosphotransferase activity was confirmed for the recombinant GAPDH.Nm23-H1 complex but not for either of the enzymes alone, nor was this activity observed after simple mixing of the purified proteins in vitro. The molecular mass of the highly purified recombinant GAPDH.Nm23-H1 complex suggests that a dimer of GAPDH interacts with a dimer of Nm23-H1. In contrast to the complex with GAPDH, co-expression of Nm23-H1 with antioxidant protein (MER-5) or creatine kinase did not activate the protein phosphotransferase function, indicating that this activation may specifically require GAPDH as a binding partner.

Distant metastasis of gastric cancer is associated with elevated expression of the antimetastatic nm23 gene

To understand the clinical significance of nm23 gene expression in gastric cancer patients, the Nm23-H1 protein level of fresh resected specimens from a total of 37 gastric cancer patients was measured by Western blot analysis. The elevated nm23 expression group (Nm23-H1 protein level in tumor tissue greater than the 75th percentile value of patients) was significantly associated with the histologically differentiated type (P = 0.036). This group had a higher incidence of distant (hematogeneous) metastasis (P = 0.0023) and a lower 2-year disease-free survival rate (P = 0.033) than the non-elevated group. The result was not consistent with the previous assumption that nm23 is an antimetastatic gene for gastric cancer.

Prognostic significance of Nm23/NDPK expression in breast carcinoma, assessed on 10-year follow-up by automated and quantitative immunocytochemical assays

The Nm23 gene has been described as an antimetastatic gene; in some studies, disease progression in patients with solid tumours is related to Nm23 protein expression, which can be detected by immunohistochemical procedures. Detection of Nm23-H1 protein in breast cancer may be relevant for the monitoring of patient therapy, provided that the technical procedures are reliable and cost-effective. The aim of the present study was to determine the prognostic significance of Nm23, assessed by quantitative immunocytochemical assays (Nm23 ICAs), under optimal technical conditions. Nm23-H1 ICAs were performed on frozen sections, using an automated immunoperoxidase technique (Ventana) and computer-assisted analysis of digitized colour microscopic images (SAMBA), in a series of 168 breast carcinomas. The results of automated quantitative ICAs were correlated with patients' follow-up (129 months). Nm23-H1 immunocytochemical expression in histological sections of tumours in which more than 3 per cent of the surface area was positively stained was significantly (0.012) correlated with longer metastasis-free survival in both node-positive and node-negative groups of patients (P = 0.032 and P = 0.036, respectively) (Kaplan-Meier log-rank test, NCSS 6.0.1 software). Nm23 expression (cut-point 3 per cent) did not, however, correlate with overall survival, or with the recurrence-free survival. In multivariate analysis (proportional hazards regression, Cox model), the prognostic significance of Nm23 in terms of metastasis-free survival was independent of tumour size and grade, and of histological grade, in the entire cohort of patients. It is concluded that Nm23 immunodetection is only of limited practical clinical relevance in breast carcinoma, even when assessed under optimal technical conditions.

The effects of n-6 polyunsaturated fatty acids on the expression of nm-23 in human cancer cells

This study examined the effect of n-6 polyunsaturated fatty acids (PUFAs) on the expression of nm-23, a metastasis-suppressor gene, in two highly invasive human cancer cell lines, HT115 and MDA MB 231. A range of n-6 and n-3 PUFAs were tested. We report that while linoleic acid and arachidonic acid reduced the expression of nm-23-H1, gamma linolenic acid (GLA) and its soluble lithium salt markedly increased the expression of the molecules. The stimulation of the expression of nm-23 by GLA was seen at both protein and mRNA levels. Up-regulation of nm-23 was also associated with a reduction of the in vitro invasiveness of these cells. It is concluded that gamma linolenic acid (GLA) enhances the expression of nm-23. This contributes to the inhibition of the in vitro invasion of tumour cells.

Immunohistochemical analysis of the nm23 gene products in testicular seminoma

The nm23 gene has been identified as a metastasis suppressor gene. To clarify the role of nm23 as a metastasis suppressor gene in testicular seminoma, the expression of the nm23-H1 and -H2 proteins (human nucleoside-diphosphate kinase-A and -B) was immunohistochemically examined in 43 patients. Thirty-six (84%) and 21 (49%) of the 43 primary tumors were positive for the nm23-H1 and -H2 proteins, respectively. There was no significant difference in either nm23-H1 or -H2 expression between the 24 primary non-invasive tumors and the 19 primary invasive tumors, or between the 31 primary tumors without metastasis and the 12 primary tumors with metastasis. In all, and 5 of 6 metastatic tumors, the expression of nm23-H1 and -H2 proteins was observed, respectively, and the expression was not decreased in the metastatic tumors, compared to the primary tumors. In conclusion, the immunohistochemical expression of both the nm23-H1 and -H2 gene products is not associated with the metastatic status or the invasive status of testicular seminoma, and it is unlikely to be a useful non-metastatic indicator for testicular seminoma. Further studies are needed to elucidate the biological role of nm23.

Expression of nm23 protein in pulmonary adenocarcinomas: inverse 1orrelation to tumor progression

Immunohistochemical assessment was made of nm23 protein expression in pulmonary adenocarcinoma. Of the 147 adenocarcinomas 67% (99/147) were weakly and 33% (48/147) strongly positive for nm23 protein. nm23 protein expression in primary tumors was shown to correlate inversely with advancing pathologic stage and the degree of metastasis in regional lymph nodes (P < 0.05). The staining of tumors without nodal metastasis was more intense than with nodal metastasis (P < 0.02). Nodal metastasis was seen in 37% (55/147) cases examined. The immunoreactivity to nm23 protein in tumor cells of nodal metastasis was essentially the same as in those of primary tumors (P < 0.01). Significant correlation between patient prognosis and immunoreactivity for nm23 in primary tumors (P < 0.05) was demonstrated. But none could be found between immunoreactivity and other parameters such as histologic grading, distant metastasis, tumor size or disease-free survival. Neither was there any significant correlation between pathologic parameters examined and the expression of nm23 in any histologic subtype. Multivariate analysis using Cox's proportional hazards regression model with five variables indicated nm23 and lymph node metastasis to contribute to overall patient survival. Based on risk ratio disadvantageous state/advantageous states, the gravity of prognostic factors was assessed for lymph node metastasis as 9.25, nm23 expression as 2.06, distant metastasis as 1.23, pathologic stage as 0.78 and tumor size as 0.77. The results suggested that in pulmonary adenocarcinoma a reduced expression of nm23 protein was associated with lymph node metastasis and poor patient survival.

Suppression of human melanoma metastasis following introduction of chromosome 6 is independent of NME1 (Nm23)

Metastasis is suppressed more than 95% following microcell-mediated transfer of a single copy of neomycin-tagged human chromosome 6 (neo6) into the human melanoma cell lines C8161 and MelJuSo. Concomitant with metastasis suppression is upregulation of NME1 (Nm23-H1) mRNA and protein expression. The purposes of this study were to determine whether NME1 expression was responsible for metastasis suppression in neo6/melanoma hybrids, and whether genes on chromosome 6 regulate NME1. Using neo6/C8161 cells, transfection of CAT reporter constructs linked to the NME1 promoter failed to consistently induce CAT. Therefore, it does not appear that genes on chromosome 6 directly control transcription of NME1. Transfection and overexpression of NME1 in MelJuSo, under the control of the CMV promoter, resulted in 40-80% inhibition of lung metastasis following i.v. inoculation of 2 x 10(5) cells. Only one transfectant of C8161 subclone 9 (C8161cl.9) cells was suppressed for metastasis. Control transfections with pCMVneo or pSV2neo did not suppress metastasis in either cell line. Taken together, these data suggest that NME1 can reduce metastatic potential of some human melanoma cells; but, this inhibitory activity appears to be independent of the metastasis suppression following introduction of chromosome 6 into C8161 and MelJuSo human melanoma cell lines.

nm23--relationship to the metastatic potential of breast carcinoma cell lines, primary human xenografts, and lymph node negative breast carcinoma patients

BACKGROUND

Since the discovery of nm23 (nonmetastatic) by Steeg et al. in 1988, a number of tumor cohort studies have shown an inverse relationship between the levels of expression of the nm23-H1 protein and disease aggressiveness and tumor metastatic potential.

METHODS

The relationship between the expression of nm23 protein and the metastatic potential of human breast carcinoma was analyzed in cell lines, xenografts, and in a retrospective lymph node negative breast carcinoma population. The lymph node negative breast carcinoma study was comprised of 40 patients: 19 with nonrecurrent and 21 with recurrent disease. The 40 patients were matched according to age, cathepsin D, tumor size, percent S-phase, DNA ploidy, steroid receptor status, and tumor grade. Nm23-H1 protein levels in cell lines and xenografts were analyzed quantitatively using Western blot analyses and semiquantitatively in tissue sections using immunocytochemistry. Immunocytochemical analysis of lymph node negative breast tumors was graded as the percent of tumor staining positive for nm23 and the intensity of staining. The metastatic potentials of the cell lines and xenografts were assessed as the ability to form metastatic lesions in nude mice. In the lymph node negative breast carcinoma patients, the metastatic potential was characterized as the incidence of breast carcinoma recurrence.

RESULTS

The MCF-7 cell line expressed four- and tenfold higher levels of nm23-H1 than the highly metastatic MDA-MB-435 and MDA-MB-231 cells, respectively. Among the xenografts and cell lines, there was an inverse correlation between nm23-H1 expression and metastatic potential in athymic nude mice (correlation coefficient [R] = -0.51). The differences between the levels of nm23-H1 among the metastatic and nonmetastatic cell lines and xenografts were not statistically significant. Statistical analyses indicated that neither the intensity nor the percent of tumor staining positive for nm23 expression was correlated to the recurrence of breast carcinoma in the lymph node negative patient population that had been matched for other clinical prognostic markers.

CONCLUSIONS

There was an inverse correlation (R = 0.51) between the levels of nm23-H1 expression in cell lines and xenografts and the metastatic potential in nude mice. In the retrospective lymph node negative breast carcinoma population, no clear association was demonstrated between the expression of nm23 and breast carcinoma recurrence. This observation suggests the nm23 expression does not predict outcome in lymph node negative breast carcinoma patients.

NM23 gene expression in human breast carcinomas: loss of correlation with cell proliferation in the advanced phase of tumor progression

NM23 is a protein associated with tumor progression, expressed in all tissues and in human tumors. Reduced expression of NM23.H1 is related to high incidence of lymph node and distant metastasis or to poor prognosis of the patient in several human malignant tumors. In this study we analyze NM23 expression in non-neoplastic mammary tissues surrounding the tumoral lesions, in human mammary carcinomas and in lymph node metastasis. Our analysis shows that NM23.H1 expression is lower in the mammary cells surrounding the tumor than in the tumor itself. In the primary tumors we observed a negative trend between degree of local invasion and level of NM23.H1 expression. A further decrease of NM23.H1 was detected in the invasive tumors that metastasized to axillary lymph nodes and in the metastasis. NM23.H2 was always more highly expressed than NM23.H1, and reduced expression of NM23.H1 but not NM23.H2 was concordant with the presence of lymph node metastasis or local invasiveness of the primary tumor. A positive correlation between NM23.H1 mRNA content and cell growth rate of breast tumor cells has been confirmed. However, this trend was not maintained in cancer cells from tumors that metastasized to axillary lymph nodes and in metastatic cells; in these 2 situations the NM23.H1 mRNA content varied without any relationship to the proliferative rate of the cells. In addition, in comparison with the initial tumor, the metastatic cell population showed a strong decrease of NM23.H1 expression and increased proliferative activity.

Expression of metastasis suppressor gene nm23 in human hepatocellular carcinoma

AIM: To investigate the relationship between the expression of nm23-Hi mRNA and the metastatic potential of hepatocellular carcinoma (HCC).

METHODS: The expression of nm23-H1 mRNA was detected in 24 cases of HCC by in situ hybridization using digoxigenin-labeled nm23-H1 antisense cRNA probe. Twenty-four HCC specimens were divided into two groups according to the following criteria: (1) metastasis in portal lymph nodes; (2) the number of tumors in the liver; (3) cancerous emboli in the portal vein; and (4) the existence of satellite lesions. We named those meeting criteria (1) or (2) and (3), or (3) and (4) high metastatic potential (n = 6); and the others formed the low metastatic potential group (n = 18).

RESULTS: Positive results of in situ hybridization showed granules or masses in the cytoplasm. In the low metastatic potential group strong staining was obtained in ten specimens, while in the high metastatic potential group there was none. Three negative results were found in the high metastatic potential group, and one in the low metastatic potential group (P < 0.05). The expression of nm23-H1 mRNA was not correlated with some clinical factors, such as tumor size or the background liver disease.

CONCLUSION: The expression of nm23-H1 mRNA is inversely correlated with HCC metastatic potential, and can be considered as an index which indicates the metastatic potential of HCC.

NM-23 H1 immunohistochemistry is not useful as predictor of metastatic potential of colorectal cancer

This study aimed to investigate whether immunohistochemical staining for nm23-H1 protein in the primary tumour is correlated with tumour stage, tumour differentiation, DNA ploidy, cell proliferative index, p53 status and patient survival time in colorectal cancer. Full-cross colorectal cancer biopsies were collected from 202 consecutive surgical specimens between 1987 and 1990. Immunohistochemical expression of nm23-H1 protein was investigated in cryosections, using a monoclonal anti-nm23-H1 antibody (clone NM 301). The staining pattern was classified as follows: strong homogeneous intensity, moderate homogeneous intensity, moderate focal intensity, or as negative. Immunohistochemical expression of p53 was investigated using a monoclonal anti-p53 antibody (DO-7). The DNA ploidy and cell proliferative index were determined by flow cytometry. Possible correlation between nm23-H1 staining patterns and the other studied tumour characteristics was explored at the end of 1994. Median survival time of living patients was 66 months, range 50-93 months. No correlation was found between various nm23-H1 staining patterns and tumour stage, cell proliferative index or p53 status. Nm23-H1-negative tumours and tumours with moderate focal staining intensity were less differentiated than tumours with strong homogeneous or moderate homogeneous staining intensity (P < 0.05). Of the nm23-H1-negative tumours, a significantly higher number was near-diploid rather than aneuploid, as compared with those expressing positive nm23-H1 (P < 0.05). The number of dead patients in Dukes' stages B and C did not correlate significantly with the nm23-H1 staining pattern. The nm23-H1 staining pattern alone, or combined with either of the other explored tumour characteristics, did not correlate with patient survival time. Immunohistochemical studies of the nm23-H1 protein expression are of minor value in the staging and prognostic prediction of colorectal cancer.

Site-directed mutagenesis of nm23-H1. Mutation of proline 96 or serine 120 abrogates its motility inhibitory activity upon transfection into human breast carcinoma cells

We report the first correlation of Nm23 sequence and its tumor metastasis-suppressive capacity using site-directed mutagenesis and an in vitro tumor cell motility assay. MDA-MB-435 human breast carcinoma cells were transfected with a control expression vector (pCMVBamneo), the vector containing the wild type nm23-H1, or the nm23-H1 vector encoding mutations at the following amino acids: serine 44, a phosphorylation site; proline 96, the k-pn mutation in the Drosophila nm23 homolog that causes developmental defects; histidine 118, involved in Nm23's nucleoside diphosphate kinase activity; and serine 120, a site of mutation in human neuroblastomas and phosphorylation. The wild type nm23-H1 transfectants were 44-98% less motile to serum and 86-99% less motile to autotaxin than control vector transfectants. The proline 96 k-pn, serine 120 to glycine, and to a lesser extent serine 120 to alanine mutant nm23-H1-transfected cell lines exhibited motility levels at or above the control transfectants, indicating that these mutations can abrogate the motility-suppressive phenotype of nm23-H1. No effect was observed on cellular proliferation, nor were the serine 44 to alanine nm23-H1 mutant transfectants motile, demonstrating the specificity of the data. The data identify the first structural motifs of nm23-H1 that influence its metastasis suppressive effect and suggest complex biochemical associations or activities in the Nm23 suppressive pathway.

Nm23 expression in endometrial and cervical cancer: inverse correlation with lymph node involvement and myometrial invasion

The expression of nm23 has been shown to correlate in some solid tumours with their metastatic potential and to be associated with a favourable prognosis in human breast cancer and melanoma. In breast and ovarian cancer nm23 expression is also correlated with lymph node involvement. We analysed the expression of nm23-H1 and -H2 in normal endometrium and in endometrial and cervical cancer by both Northern and Western blotting. Cellular localisation of Nm23-H1 was visualised by immunohistochemistry mostly in the cytoplasm. Both isoforms of Nm23 were present in all the samples analysed, and a clear direct correlation between Nm23-H1 and -H2 levels was evident. Median nm23-H2 levels were higher than than -H1 levels in both tissues. Cervical cancer patients with lymph node involvement were shown to have significantly lower protein levels of Nm23 (P < 0.007 for H1 and P < 0.009 for H2), and a similar trend was also evident in endometrial cancer. Furthermore, the degree of myometrial invasion in endometrial cancer patients was also inversely correlated with Nm23-H1 levels of expression (P < 0.003). Nm23 level may therefore be taken into consideration as a new marker in the prognostic characterisation and in the treatment planning of uterine tumour patients.

Expression of nm23-H1 in prostatic intraepithelial neoplasia and adenocarcinoma

The product of the nm23-H1 gene has been reported to be related to the metastatic potential of several tumors. Although several studies have characterized the expression of the nm23-H1 gene product in prostatic adenocarcinoma, little is known of the expression of this protein in prostatic intraepithelial neoplasia (PIN), a putative precancerous lesion. The authors used immunohistochemistry to examine the expression of the nm23-H1 protein in PIN as well as benign and malignant prostatic tissue. A monoclonal antibody to nm23-H1 (Novocastra, Newcastle upon Tyne, UK, clone 37.6) and a biotin/strepavidin detection system were used for antigen localization. Weak to moderate immunostaining was consistently detected in the benign glandular epithelium of 28 radical prostatectomy specimens. In contrast, strong immunostaining was detected in the glandular epithelium in PIN lesions of 19 radical prostatectomy specimens examined. Strong immunostaining was also frequently detected in the malignant cells of 39 localized prostatic adenocarcinomas, as well as 7 metastatic lesions. These findings show a phenotypic similarity of PIN to prostatic adenocarcinoma with respect to nm23-H1 expression. Furthermore, strong expression of nm23-H1 likely represents an early event in the development of prostatic adenocarcinoma.

Expression of NM23 in human melanoma progression and metastasis

NM23 is a putative metastasis-suppressor gene for some human cancers. Here we have studied NM23 expression during melanoma progression using Northern blotting and immunocytochemistry. There was no significant difference in the average amounts of NM23 mRNA between cell lines derived from metastatic and primary melanomas. The level of NM23 mRNA was also determined for three pairs of poorly metastatic parental (P) and their highly metastatic variant (M) cell lines; the ratios for M/P were 1.2, 0.98 and 0.80. Next we used immunocytochemistry to study NM23 protein in normal skin, benign naevi and primary and metastatic melanomas. Melanocytes in all normal skin and benign samples were positive for NM23; however most primary melanomas (7/11) were not stained by the antibody. All metastatic melanoma samples (5/5) were positively stained. Findings were similar with an antiserum reactive with both forms of NM23 (H1 and H2), and with an antibody specific for NM23-H1. No relationship was apparent between NM23 immunoreactivity in primary tumours and their aggressiveness or prognosis. Hence, in contrast to the situation described for murine melanoma, the amount of NM23 mRNA or protein in human melanoma did not correlate inversely with metastasis.

Evaluation of the prognostic significance of nm23/NDP kinase and cathepsin D in anal carcinomas. An immunohistochemical study

Reduced expression of nm23/NDP kinase and increased expression of cathepsin D seem to be correlated with a high metastatic potential for a variety of malignancies. Nm23/NDP kinase and cathepsin D have been correlated with several clinical variables, including survival in 96 patients with squamous cell carcinoma of the anal canal. Immunohistochemical methods were used on paraffin-embedded biopsies. Seventy-six (79%) anal carcinomas were nm23/NDP kinase positive, whereas 35 (36%) and 28 (29%) of the cases were cathepsin D positive in tumor cells and stromal cells, respectively. We have found no indication that the extent of cathepsin D staining has any prognostic significance. The overall survival of patients with tumours positive for nm23/NDP kinase in the cytoplasm was significantly shorter than that of patients with anal carcinomas negative for nm23/NDP kinase.

Analysis of nm23-H1 expression in breast cancer. Correlation with p53 expression and clinicopathologic findings

Metastasis is the most frequent cause of death in patients with breast cancer. The nm23-H1 and p53 genes have been involved in the development of breast cancer metastasis. We have analyzed the correlation between the expression of nm23 protein and several established clinicopathologic factors. Our results show that the antimetastatic role of nm23-H1 is not related to the cell proliferative status or tumor grade and that it is not associated with the expression of p53. We also demonstrate a strong inverse relationship between the expression of nm23-H1 protein, lymph node metastasis and vascular invasion. These data support the antimetastatic role of the nm23-H1 gene and suggest that nm23-H1 and p53 genes may be involved in different steps of the metastatic process.

Potential prognostic value in human breast cancer of cytosolic Nme1 protein detection using an original hen specific antibody

The metastasis-suppressor nme gene (also called nm23), first identified in murine melanoma cells, exists as two forms in human: nme1 and nme2. However, only the lack of expression of nme1 has been related to distant metastasis appearance in human breast cancer. The aim of this work was first to raise specific antibodies to allow the analysis of Nme1 and then, with this specific tool, to evaluate the predictive value of Nme1 detection in cytosolic extracts of human breast tumours. We obtained a hen antibody that specifically reacts with Nme1 without any cross-reaction with Nme2. We analysed the expression of the protein in 59 human breast tumours and found a significant relationship between this expression and oestrogen receptor status (P<0.001). Moreover, Nme1 expression is related to metastasis-free survival (P<0.001) and survival of patients (P<0.001). The determination of Nme1 expression in primary tumours using our antibody should be an interesting predictive test of the metastasis for clinical investigations.

Immunohistochemical analysis of nm23 protein in transitional cell carcinoma of the bladder

OBJECTIVES

To elucidate the clinical significance of the nm23 gene product in transitional cell carcinoma (TCC) of the bladder.

PATIENTS AND METHODS

The immunoreactivity of nm23 protein and proliferating cell nuclear antigen (PCNA) were evaluated in paraffin-embedded tumour samples obtained from 74 patients with TCC of the bladder who underwent total cystectomy between 1981 and 1993 and compared with the histological findings and clinical outcome.

RESULTS

The immunoreactivity of nm23 protein was positive near basement membrane in normal transitional epithelium and superficial TCCs; it could also be positive at the invasive front of TCCs. The immunoreactivity of nm23 protein in TCCs was significantly higher than that in normal transitional epithelium and correlated significantly with the expression of PCNA and with histological grade. Similarly, immunoreactivity was significantly higher in invasive TCCs than in superficial TCCs; however, there was no significant difference between superficial TCCs and normal transitional epithelium. Immunoreactivity of nm23 protein was not associated with the early development of metastasis after radical surgery or with a favorable clinical outcome.

CONCLUSION

Immunoreactivity of nm23 protein appeared to be associated with the proliferation and progression of TCC of the bladder. The potential role of nm23 as a suppressor of the metastatic activity of tumours was less prominent, partly because of mutations of nm23 in TCCs of the bladder.

A novel serine/threonine-specific protein phosphotransferase activity of Nm23/nucleoside-diphosphate kinase

Two human nm23 genes have been identified, designated nm23-H1 and nm23-H2, which encode the 88% identical nucleoside-diphosphate kinase (NDPK) A and NDPK B polypeptides, respectively. The nm23-H1 gene product has been shown to play a functional role in the suppression of tumor metastasis. The Nm23 proteins/NDPK are highly conserved throughout evolution and are implicated in controlling cellular differentiation and development in various species, while the underlying mechanisms remain undefined. Neither the NDPK activity nor the DNA-binding activity, identified recently for NDPK B, can satisfactory explain the regulatory functions of Nm23. The present study provides evidence that purified Nm23 proteins are capable of transferring a phosphate group to other proteins when non-denaturing amounts of urea are present. This novel Nm23/NDPK activity was found to be specific for serine and threonine residues, and the transphosphorylation of substrate proteins occurred stoichiometrically. Because of the absence of a substrate turn-over, the novel function was termed protein phosphotransferase activity instead of protein kinase activity. It is demonstrated that urea stimulates the interaction of NDPK with other proteins. Identical phosphoprotein patterns were obtained using purified NDPK preparations from human, Drosophila, yeast and Dictyostelium in the presence of urea. Partially purified NDPK from human erythrocytes produced a similar phosphorylation pattern independent of urea addition and also acted stoichiometrically. In this preparation, a protein phosphotransferase activity of Nm23 species may possibly be generated and/or stabilized by the interaction with copurified proteins. Using different mutants of Dictyostelium NDPK it was shown that the protein phosphotransferase activity depends on the same active site as the NDPK activity. A phosphotransfer mechanism analogous to that of protein-histidine kinases is proposed, involving a high-energy phosphohistidine intermediate. Furthermore, the novel Nm23 function is compared with an apparently similar protein phosphotransferase activity which was observed previously with partially purified NDPK from different plant species.

Immunohistochemical analysis of nm23 protein expression in malignant bone tumors

Expression levels of nm23 protein in 72 malignant bone tumors comprising 41 osteosarcomas, 22 chondrosarcomas, 6 Ewing's sarcomas, and 2 malignant fibrous histiocytomas were examined immunohistochemically, using anti-nm23 protein polyclonal antibody, and compared with 51 cases of benign bone tumors or tumor-like lesions. Malignant bone tumors showed significantly higher nm23 protein expression than benign bone tumors or tumor-like lesions (P < 0.0001). In chondrosarcoma, nm23 expression increased in high-grade tumors (grade I versus grade II and III: P = 0.0229). In the cases of osteosarcoma, however, grade IV osteosarcomas showed decreased expression of nm23 compared with grade III tumors (P = 0.0122). There was no significant relationship between nm23 expression and histological type. nm23 expression had no correlation with metastatic potential in osteosarcoma, although the therapy was not uniform in our cases. Furthermore, in 6 cases of osteosarcoma and 1 case of Ewing's sarcoma, there was no clear tendency for a decrease of nm23 in the metastatic sites compared with primary sites, as reported in breast cancer. These results showed that, in contrast to reports on breast cancer and experimental models, nm23 protein expression in human bone tumors may be associated with malignant potentiality, except in cases of osteosarcoma.

Immunohistochemical detection of nm23/NDP kinase and cathepsin D in medullary carcinomas of the thyroid gland

Reduced expression of nm23/NDP kinase and increased expression of cathepsin D seem to be correlated with the high metastatic potential in a variety of malignancies. The expression of nm23/NDP kinase and that of cathepsin D have been evaluated by means of an immunohistochemical technique in paraffin-embedded tissues from 44 primary medullary carcinomas of the thyroid gland (MCT) and from the corresponding lymph node metastases in 32 of these cases. In addition, lymph node metastases from 4 cases were studied. We found that 36 of 44 (82%) primary and 26 of 36 (72%) lymph node metastatic MCT were nm23/NDP kinase positive, whereas 14 of the 44 (32%) primary and 17 of the 36 (47%) lymph node metastatic MCT were cathepsin D positive. We found no indication that the nm23/NDP kinase level has any prognostic significance in MCT. The cathepsin D level is close to being prognostically significant in this study, and we cannot exclude the possibility that it could be of prognostic value. However, it seems to be quite weak, and therefore of little use in a clinical situation.

The potential roles of nm23 in cancer metastasis and cellular differentiation

The majority of cancer patients succumb to the consequences of metastatic disease. A correlation of increased nm23 expression to low metastatic potential has been established in several malignancies, based on published prognostic studies with tumour cohorts and transfection studies. Transfection of highly metastatic MDA-MB-435 human breast carcinoma cells with nm23-H1 cDNA resulted in a significant reduction in the metastatic potential in vivo. These transfections also showed inhibition of colonisation and motility, as well as morphological and biosynthetic differentiation in vitro. The biochemical mechanism of Nm23-H1 action, as well as the identity of proteins involved in its functional biochemical pathway, are still unknown. We summarise published and recent research concerning the role of the nm23 gene in metastasis and normal cellular differentiation.

Increased expression of the NME1 gene is associated with metastasis in epithelial ovarian cancer

The genetic events involved in the development of metastases of epithelial ovarian cancer are largely unknown. One gene postulated to play a role in tumour metastasis suppression is NME1 (nm23-H1), and an inverse relationship between NME1 expression and metastatic potential has been observed for some solid tumours. In this study we have investigated the levels of mRNA expression of the 2 isoforms of the NME gene, NME1 and NME2. A maximum of 45 tumours samples from 33 patients were available for Northern blot analysis. We observed variable levels expression of NME1 and NME2 mRNA. The average level of NME1, but not NME2, mRNA expression was statistically higher in metastatic biopsies when compared with primary tumour biopsies. To examine the possible tumour suppressor gene role of NME1 in ovarian tumours, 76 patients were investigated by Southern blot analysis to determine the rate of allelic deletion. Allele loss at 5 other chromosome 17 loci (D17S5, TP53, NF1, D17S74, D17S4) was also evaluated for many of these 76 patients. Allele loss was observed in 22/30 (73%) informative patients at the NME1 locus. We also observed high rates of allele loss at the other loci evaluated. No correlations with clinical stage, histological subtype or patient survival were observed in either mRNA or DNA analyses. We have established that tumour progression in ovarian cancer is accompanied by over-expression of the NME1 gene; however, despite high rates of allele loss at the NME1 locus, the concept that NME1 may be a candidate tumour suppressor gene in ovarian cancer cannot be confirmed by this study.

The c-erbB-2 proto-oncogene as a prognostic and predictive marker in breast cancer: a paradigm for the development of other macromolecular markers--a review

Seven years after the initial studies of the prognostic value of the proto-oncogene c-erbB-2 in breast cancer, its role is still being defined. The interpretation of studies on the use of this gene and its protein product in prognostic and predictive tests for breast cancer is complicated by multiple methodologies and the inherent difficulties in the studies. The work has moved beyond the stage at which small studies with short follow-up (useful for hypothesis generation) are of value, to the stage in which large studies with sufficient statistical power to find significant correlations are central. These larger studies do not lend support for the use of c-erbB-2 in the evaluation of axillary-node-negative patients, the group of breast cancer patients for whom refinement of prognostic estimates is now most important. There are, however, hints that c-erbB-2 may have value in predicting response to certain treatments, though the studies so far are too few, often too small and too conflicting to reliably confirm this.

Altered expression of nm23-H1 and c-erbB-2 proteins have prognostic significance in adenocarcinoma but not in squamous cell carcinoma of the uterine cervix

BACKGROUND

The reduced expression of nm23-H1 protein and/or overexpression of c-erbB-2 protein reportedly is associated with a high incidence of lymphatic metastasis or poor prognosis of the patient in a variety of human malignant tumors.

METHODS

The expression patterns of nm23-H1 and c-erbB-2 proteins were analyzed by immunohistochemical staining using formalin fixed, paraffin embedded sections of 88 cases of invasive carcinoma (39 matched pairs of adenocarcinoma and squamous cell carcinoma, 8 cases of adenosquamous carcinoma, and 2 cases of undifferentiated carcinoma) and 31 cases of preinvasive lesions of the uterine cervix.

RESULTS

Expression of nm23-H1 was detected in 46% of adenocarcinoma and in 36% of squamous cell carcinoma of the uterine cervix, whereas c-erbB-2 expression was evident in 49% and 38%, respectively. Negative expression of nm23-H1, positive expression of c-erbB-2, and a combined nm23-H1-negative and c-erbB-2-positive expression were associated with a high incidence of lymph node involvement (P = 0.36, P = 0.0015, P = 0.0055, respectively) and with poor prognosis of patients (P = 0.034, P = 0.014, P = 0.00008, respectively) with adenocarcinoma of the uterine cervix, but not in those with squamous cell carcinoma. Multivariate analysis using the Cox's proportional hazard model also revealed that these three factors significantly contributed to the prognosis of patients with cervical adenocarcinoma.

CONCLUSIONS

Reduced expression of the nm23-H1 protein, increased expression of the c-erbB-2 protein, and a combined nm23-H1-negative and c-erbB-2-positive expression have prognostic significance in patients with adenocarcinoma, whereas they may not be associated with the prognosis of squamous cell carcinoma of the uterine cervix, nm23-H1 and c-erbB-2 proteins may have different functions according to the subtype of cervical carcinoma.

Mutations in breast cancer

The genetics of spontaneous breast cancer is reviewed. We have identified three regions of amplification and nine chromosomal arms with deletions in the genome. The significance and interrelations of these mutations is discussed with respect to the complex genetics of breast carcinoma. Recent work identifying a commonly deleted region between D17S846 and D17S746 is presented, which is approximately 0.5-1.0 Mb centromeric to the newly described BRCA1 gene candidate. Possible explanations for the different locations of our deleted region and the BRCA1 gene are presented.

A novel function for the nm23-H1 gene: overexpression in human breast carcinoma cells leads to the formation of basement membrane and growth arrest

BACKGROUND

We have developed a culture system using reconstituted basement membrane components in which normal human mammary epithelial cells exhibit several aspects of the development and differentiation process, including formation of acinar-like structures, production and basal deposition of basement membrane components, and production and apical secretion of sialomucins. Cell lines and cultures from human breast carcinomas failed to recapitulate this process. The data indicate the importance of cellular interactions with the basement membrane in the regulation of normal breast differentiation and, potentially, its loss in neoplasia.

PURPOSE

Our purpose was to use this assay to investigate the role of the putative metastasis suppressor gene nm23-H1 in mammary development and differentiation.

METHODS

The metastatic human breast carcinoma cell line MDA-MB-435, clones transfected with a control pCMVBamneo vector, and clones transfected with pCMVBamneo vector containing nm23-H1 complementary DNA (the latter of which exhibited a substantial reduction in spontaneous metastatic potential in vivo) were cultured within a reconstituted basement membrane. Clones were examined for formation of acinus-like spheres, deposition of basement membrane components, production of sialomucin, polarization, and growth arrest.

RESULTS

In contrast to the parental cell line and control transfectants, MDA-MB-435 breast carcinoma cells overexpressing Nm23-H1 protein regained several aspects of the normal phenotype within reconstituted basement membrane. Nm23-H1 protein-positive cells formed organized acinus-like spheres, deposited the basement membrane components type IV collagen and, to some extent, laminin to the outside of the spheres, expressed sialomucin, and growth arrested. Growth arrest of Nm23-H1 protein-positive cells was preceded by and correlated with formation of a basement membrane, suggesting a causal relationship.

CONCLUSION

The data indicate a previously unidentified cause-and-effect relationship between nm23-H1 gene expression and morphological-biosynthetic-growth aspects of breast differentiation in this model system.

IMPLICATIONS

While the basement membrane microenvironment is capable of directing the differentiation of normal human breast cells, neoplastic transformation abrogates this relationship, suggesting that intrinsic cellular events are also critical to this process. The data identify nm23-H1 gene expression as one of these events, suggesting an important role in the modulation of cellular responsiveness to the microenvironment. The data also identify previously unknown growth inhibitory effects of nm23-H1 gene overexpression.

High level of Nm23-H1 gene expression is associated with local colorectal cancer progression not with metastases

This study aimed to determine the expression of Nm23-H1 in colorectal cancer and liver metastases and to correlate Nm23-H1 expression with clinicopathological variables. Specimens from 59 primary colorectal cancers and five liver metastases were studied using Northern blot hybridisation. The mean +/- s.e. of tumour/normal (T/N) ratio of Nm23-H1 RNA expression was 4.3 +/- 0.4 (P < 0.001) and 5.1 +/- 0.90 (P < 0.01) for colorectal cancer and liver metastases respectively. No significant relationship was observed between the level of Nm23-H1 RNA and the patient's age, sex, tumour location, differentiation, presence of lymph node involvement or distant metastases. Nm23-H1 RNA level was 2.6 +/- 0.5 for tumour size less than 3.0 cm and 4.6 +/- 0.5 for those > or = 3.0 cm (P = 0.05). There appeared to be a trend between increasing relative Nm23-H1 RNA and bowel wall invasion, irrespective of metastatic status (T1 = 1.9 +/- 0.3, T2 = 4.1 +/- 0.6, T3 = 4.1 +/- 0.5 and T4 = 6.4 +/- 1.6). This difference was statistically significant when T1 was compared against > or = T2 lesions (P = 0.01). Western blot analysis reveals two Nm23H-1 bands (17.0 kDa and 18.5 kDa). In 16 colorectal patients, the T/N fold-increase in protein expression was 2.66 +/- 0.46 (P < 0.001) and 2.40 +/- 0.32 (P < 0.001) for the 17.0 and 18.5 kDa band respectively. Both Nm23-H1 RNA and protein levels in primary colorectal cancers do not appear to correlate with synchronous regional or distant metastases. Since Nm23-H1 RNA expression is associated with increasing tumour size and tumour local invasion, Nm23-H1 RNA expression may be associated with local disease progression.

nm23-H1 expression and disease recurrence after surgical resection of small hepatocellular carcinoma

BACKGROUND/AIMS

The nm23-H1 gene is thought to act as a metastasis-suppressor gene. This study investigates the relationship between nm23-H1 messenger RNA (mRNA) expression and intrahepatic tumor recurrence after surgical resection of small hepatocellular carcinoma.

METHODS

Seventeen cirrhotic patients with solitary hepatocellular carcinoma < 5 cm underwent surgical resection. In 7 patients, the neoplasm recurred after a 12-month median follow-up, whereas the other 10 patients were free of disease after a 30-month median follow-up. Both groups were similar according to age, sex, etiology, status of the underlying liver, tumor size, and other pathological characteristics of the neoplasm. nm23-H1 mRNA levels were assessed in matched tumor and surrounding cirrhotic liver samples by Northern blot hybridization using a 900-base pair probe, which is a BamHI fragment of pnm23-H1 recombinant complementary DNA clone encoding the nm23-H1 human gene.

RESULTS

Eight of the 10 patients without disease recurrence during follow-up showed nm23-H1 overexpression with an increase ranging between three- and 45-fold when compared with the nontumoral surrounding liver. Only 1 of the 7 patients with tumor recurrence showed higher nm23-H1 mRNA levels in the tumor than in the nonneoplastic sample (P = 0.013).

CONCLUSIONS

nm23 mRNA overexpression in small solitary hepatocellular carcinoma is associated with a lower recurrence rate after surgical resection, suggesting that this gene may participate in the metastatic dissemination of this neoplasm.

Heterogeneous expression of nm23 gene product in noninvasive breast carcinoma

BACKGROUND

The two major types of noninvasive breast carcinoma, ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS), are quite different in their histopathologic appearance and clinical implications. LCIS is only a marker of an increased risk of later development of invasive carcinoma, whereas most DCIS lesions are at least nonobligate precursors of invasive carcinoma. DCIS is a heterogeneous group of lesions composed of several distinct subtypes, with only the comedo subtype having immediate malignant potential. The authors' purpose was to analyze noninvasive carcinomas for the presence of a gene product (nm23) indicative of a favorable prognosis in invasive carcinomas to determine differences (1) among the different types of CIS and (2) in CIS with and without an accompanying invasive component.

METHODS

Immunohistochemical methods were used to detect nm23 gene product in archival material from two groups of patients: Group 1 consisted of 54 cases of purely noninvasive carcinoma, and Group 2 consisted of 55 examples of noninvasive carcinoma associated with an invasive component.

RESULTS

Among the cases of CIS with no invasion, LCIS and comedo DCIS expressed more nm23 than noncomedo DCIS (P < or = 0.03). There were no differences among these CIS subtypes in the group with invasion. Comparing subtypes of CIS in the groups with or without invasion, only comedo DCIS was significantly different, with greater expression in the CIS group with no invasion compared with comedo DCIS associated with an invasive component (P = 0.04).

CONCLUSIONS

These results support the special nature of LCIS and the heterogeneous nature of DCIS. The in situ component attending an invasive component may be different from anatomically similar lesion without associated invasion. The absence of nm23 in comedo DCIS may be indicative of invasive capacity.

Expression of human nm23-H1 and nm23-H2 proteins in hepatocellular carcinoma

BACKGROUND

The expression of nm23-H1 and nm23-H2 proteins in 25 hepatocellular carcinomas was studied immunohistochemically.

METHODS

Tissue specimens were reacted with anti-human nm23-H1 and nm23-H2 monoclonal antibodies (MoAb) (H1-229 and H2-206, respectively) and then stained by the biotin-streptoavidin complex method.

RESULTS

Adjacent nontumorous tissues were intensely stained with nm23-H1 and nm23-H2. Of the 25 hepatocellular carcinomas, 60% were positive for MoAb H1-229, and 68% were positive for MoAb H2-206. These immunoreactivities were most common in the cytoplasm of tumor cells. There was no significant correlation between the expression of nm23-H1 protein and tumor size, Edmondson's histopathologic classification, or invasion of the capsule. However, the authors observed an inverse relationship between nm23-H1 expression and intrahepatic metastases of hepatocellular carcinomas. There was no significant correlation between the expression of nm23-H2 protein and clinicopathologic findings. Only a short survival period was observed in patients with hepatocellular carcinoma with reduced nm23-H1 or nm23-H2 proteins.

CONCLUSIONS

The results suggest that nm23-H1 protein plays a role in the suppression of intrahepatic metastasis of hepatocellular carcinoma and that the combined expression of nm23-H1 is associated with favorable prognosis.