Quantitative distribution of cluster 1 small cell lung cancer antigen in cancerous and non-cancerous tissues, cultured cells and sera

Hepatocellular carcinoma with progenitor cell features distinguishable by the hepatic stem/progenitor cell marker NCAM

We analyzed hepatocellular carcinoma (HCC) with progenitor cell features using hepatic stem/progenitor cell marker neural cell adhesion molecule (NCAM). Approximately 8.3% of the operated HCC cases expressed NCAM, and 22.3% of the HCC patients had soluble NCAM levels >1000ng/ml (the "highly soluble" NCAM group). Soluble NCAM status was a significant independent factor predictive of long-term survival in patients with HCC, and high levels of soluble NCAM were significantly related to intrahepatic metastasis. The 140-kDa NCAM isoform was specifically detected in the "highly soluble" NCAM group of HCC patients andits related signals are potential drug targets for NCAM+ HCC.

Universal expression of cell adhesion molecule NCAM in neuroblastoma in contrast to L1: implications for different roles in tumor biology of neuroblastoma?

PURPOSE

Neuroblastoma is a biological, genetic and morphological heterogeneous tumor with a variable clinical course. NCAM is a cell adhesion molecule belonging to the immunoglobulin superfamily with structural similarities to cell adhesion molecule L1. The aim of this study was to determine the expression of NCAM in neuroblastoma and to compare the results to the findings of a previous study which examined L1 expression in the same group of patients.

MATERIALS AND METHODS

NCAM expression was investigated on a tissue array with 66 surgically resected neuroblastoma samples by immunohistochemistry with a monoclonal antibody clone 1B6 and peroxidase method.

RESULTS

Strong expression of NCAM was detected in all of the 66 (100%) neuroblastoma tumors in contrast to L1 which was not expressed in all tumors.

CONCLUSION

In contrast to L1, which was found to predict favorable outcome, NCAM is universally expressed in neuroblastoma. Therefore NCAM represents a marker for neuroblastomas irrespectively of their stages whereas L1 as an indicator for developing neuronal cells seems to identify more mature stages of this tumor. The high grade of NCAM expression might present a prerequisite for establishment of antibody-based therapies.

The bi-specific CD3 x NCAM antibody: a model to preactivate T cells prior to tumour cell lysis

To target the neural cell adhesion molecule (NCAM, CD56) on neuroblastoma by T cell-based immunotherapy we have generated a bi-specific CD3 x NCAM antibody (OE-1). This antibody can be used to redirect T cells to NCAM+ cells. Expectedly, the antibody binds specifically to NCAM+ neuroblastoma cells and CD3+ T cells. OE-1 induces T cell activation, expansion and effector function in peripheral blood mononuclear cell (PBMC)-derived CD4+ and CD8+ T cells. T cell activation was shown to depend on the presence of normal natural killer (NK) cells in the culture. Interestingly, while PBMC- derived T cells were activated by OE-1, NK cells were almost completely depleted, suggesting that T cells activated by OE-1 deleted the NK cells. Activated CD4+ and CD8+ T cells differentiate into a larger CCR7+ central memory and a smaller CCR7- effector memory cell population. Most importantly, preactivated T cells were highly cytotoxic for neuroblastoma cells. In eight of 11 experiments tumour-directed cytotoxicity was enhanced when NK cells were present during preactivation with OE-1. These data strongly support a bi-phasic therapeutic concept of primarily stimulating T cells with the bi-specific antibody in the presence of normal NCAM+ cells to induce T cell activation, migratory capacity and finally tumour cell lysis.

Ectopic expression of NCAM in skeletal muscle of transgenic mice results in terminal sprouting at the neuromuscular junction and altered structure but not function

The neuromuscular system provides an excellent model for the analysis of molecular interactions involved in the development and plasticity of synaptic contacts. The neural cell adhesion molecule (NCAM) is believed to be involved in the development and plasticity of the neuromuscular junction, in particular the axonal sprouting response observed in paralyzed and denervated muscle. In order to explore the role of myofiber NCAM in modulating the differentiation of motor neurons, we generated transgenic mice expressing a GPI-anchored NCAM isoform that is normally found in developing and denervated muscle, under the control of a skeletal muscle-specific promoter. This results in the constitutive expression of NCAM at postnatal ages, a time when the endogenous mouse NCAM is absent from the myofiber. We found that a significant number of neuromuscular junctions in adult transgenic animals displayed terminal sprouting (>20%) reminiscent of that elicited in response to cessation of neuromuscular activity. Additionally, a significant increase in the size and complexity of neuromuscular synapses as a result of extensive intraterminal sprouting was detected. Electrophysiological studies, however, revealed no significant alterations of neuromuscular transmission at this highly efficient synapse. Sprouting in response to paralysis or following nerve crush was also significantly enhanced in transgenic animals. These results suggest that in this ectopic expression model NCAM can directly modulate synaptic structure and motor neuron-muscle interactions. The results contrast with knockout experiments of the NCAM gene, where very limited changes in the neuromuscular system were observed.

Immunocytochemical assessment of bone marrow aspirates for monitoring response to chemotherapy in small-cell lung cancer patients

Recent reports have suggested that tumour cell immunodetection in bone marrow of small-cell lung cancer patients is by far more frequent than found cytohistologically and may have clinical relevance. This study evaluates primarily the efficacy of chemotherapy as method of in vivo purging, but also the relationship of marrow involvement with survival. A total of 112 bone marrow aspirates from 30 chemo-naïve patients were stained twice using anti-NCAM antibodies, first at diagnosis and then after chemotherapy (24 patients) or at disease progression (six patients). Marrow contamination was associated with lower survival (P = 0.002), and was also detected in 7/17 patients conventionally staged as having limited disease. At multivariate analysis, marrow involvement was an independent factor of unfavourable prognosis (P = 0.033). The amount of tumour contamination, before and after chemotherapy, remained unchanged also in responders and even in the subset of patients with apparent limited disease. Following chemotherapy, bone marrow became tumour negative only in 25% of initially positive responders and in none of non-responders. Our results indicate that (i) chemotherapy is not effective in purging bone marrow even in chemo-responsive patients and (ii) a subset of patients with limited disease and negative bone marrow aspirates might have a more favourable prognosis.

Effects of different immunolabeling techniques on the detection of small-cell lung cancer cells in bone marrow

Recent reports have suggested that the immunodetection of tumor cells in bone marrow of small-cell lung cancer (SCLC) patients is by far more effective than traditional cytohistological methods and that this may be clinically relevant. This study aimed to evaluate whether the level of detection of tumor cells in bone marrow is affected by different immunostaining methods. Using two anti-NCAM monoclonal antibodies (MAbs), we compared four different "sandwich" methods on cytospin preparations of the N592 human SCLC cell line and of bone marrow aspirates from 37 SCLC patients. Our data indicate that the combination of the alkaline phosphatase-anti-alkaline phosphatase and streptavidin-biotin-alkaline phosphatase complex methods provides the best results in terms of sensitivity and specificity, and of intensity of immunoreaction and absence of staining background. Moreover, bone marrow micrometastases detected by this method were prognostically relevant and identified, among patients with apparently limited disease according to conventional staging procedures, a subgroup with shorter survival. We suggest that the choice of a sensitive immunostaining technique may significantly increase the detection rate of SCLC cells in bone marrow, mirroring the biological aggressiveness of the disease.

Altered secondary myogenesis in transgenic animals expressing the neural cell adhesion molecule under the control of a skeletal muscle alpha-actin promoter

The majority of skeletal muscle fibers are generated through the process of secondary myogenesis. Cell adhesion molecules such as NCAM are thought to be intricately involved in the cell-cell interactions between developing secondary and primary myotubes. During secondary myogenesis, the expression of NCAM in skeletal muscle is under strict spatial and temporal control. To investigate the role of NCAM in the regulation of primary-secondary myotube interactions and muscle fusion in vivo, we have examined muscle development in transgenic mice expressing the 125-kD muscle-specific, glycosylphosphatidylinositol-anchored isoform of human NCAM, under the control of a human skeletal muscle alpha-actin promoter that is active from about embryonic day 15 onward. Analysis of developing muscle from transgenic animals revealed a significantly lower number of myofibers encased by basal lamina at postnatal day 1 compared with nontransgenic littermates, although the total number of developing myofibers was similar. An increase in muscle fiber size and decreased numbers of VCAM-1-positive secondary myoblasts at postnatal day 1 was also found, indicating enhanced secondary myoblast fusion in the transgenic animals. There was also a significant decrease in myofiber number but no increase in overall muscle size in adult transgenic animals; other measurements such as the number of nuclei per fiber and the size of individual muscle fibers were significantly increased, again suggesting increased secondary myoblast fusion. Thus the level of NCAM in the sarcolemma is a key regulator of cell-cell interactions occurring during secondary myogenesis in vivo and fulfills the prediction derived from transfection studies in vitro that the 125-kD NCAM isoform can enhance myoblast fusion.

The neural cell adhesion molecule NCAM in multiple myeloma

The Neural Cell Adhesion Molecule NCAM is a membrane glycoprotein and belongs to the immunoglobulin superfamily. It is expressed on neural cells as well as on various neuroendocrine tumors and can be detected in sera of patients with small cell lung cancer. Its role is attributed to tumor invasion and formation of metastases. Malignant plasma cells and a subset of plasma cells from patients with monoclonal gammopathy exhibit surface expression of NCAM whereas normal plasma cells do not express NCAM. Expression as measured by flow cytometry using anti-CD56 antibodies does not seem to correlate with clinical course, however leukemic myelomas and myeloma cell lines tend to loose NCAM surface expression. An isoform of NCAM which is rich in polysialic acids and characteristic for embryonal NCAM (eNCAM) has been shown to be elevated in sera of patients with multiple myeloma using a chemiluminescence immunoassay. Patients with progressive myeloma tend to have high serum NCAM levels above the normal range of 20 U/ml. Analysis of 125 myeloma patients suggest that serum NCAM is a valuable parameter for tumor progression rather than tumor mass. Increase in serum NCAM may be associated with loss of adhesive function.

Detection of polypeptides associated with the histopathological differentiation of primary lung carcinoma

Two-dimensional polyacrylamide gel electrophoresis combined with a non-enzymatic sample preparation technique is useful for analysing clinical tumour material. Using these techniques, we analysed the relationship between the histopathological findings in primary lung malignancies and the expression of a number of unidentified polypeptides that were detected in the molecular weight region 20-35 kDa. In this study 45 cases of primary lung cancer (PLC) (21 cases of adenocarcinoma, ten cases of squamous cell carcinoma, five cases of large-cell carcinoma, one case of adenosquamous cell carcinoma, five cases of small-cell carcinoma and three cases of carcinoid tumour) were examined. For reference, a human diploid fibroblast cell line (W138) and normal peripheral lymphocytes were used. Sixteen polypeptides were judged to be associated with histopathological features. These polypeptides seem to be valuable as differentiation markers. The simultaneous evaluation of these polypeptides and some other proliferation markers (e.g. PCNA, PCNA 'satellite', Numatin/protein B23 and lamin B) seems to clarify the characteristics of each case of PLC. Furthermore, it is possible to classify PLC based on the two-dimensional electrophoresis findings, and this classification of PLC is suggested to reflect the biological features of the tumour more precisely than that based only on morphology.

Molecular cloning of a cell-surface glycoprotein that can potentially discriminate mesothelium from epithelium: its identification as vascular cell adhesion molecule 1

It has long been a practical problem for surgical pathologists to distinguish mesothelium from epithelium in order to make a positive diagnosis of mesothelioma. In this study, we developed a new monoclonal antibody, designated MS-2761 (IgG1, k), against cultured non-neoplastic mesothelial cells. Immunohistochemistry and slot-blot analysis revealed that this monoclonal antibody reacted with 100% (12/12) of benign and malignant mesothelioma tissues and a mesothelioma cell line, but not with 99% (77/78) of epithelial tumour tissues and 97% (33/34) of epithelial tumour cell lines. A gene encoding the cell-surface antigen defined by this monoclonal antibody was isolated from a mesothelial cell cDNA library constructed with a mammalian cell expression vector through transfection of Cos-7 cells and immunoselection by panning. DNA sequencing and a database search revealed that the gene was identical to vascular cell adhesion molecule 1 (VCAM1, also referred to as INCAM110). The prominent VCAM1 transcript in mesothelium was 3.2 kb in size with seven Ig-like domains, in addition to a minor transcripts with six Ig-like domains. This monoclonal antibody potentially discriminates mesothelium from epithelium and may become a tool for differential diagnosis of mesothelioma.

Monoclonal antibody against PRAD1/cyclin D1 stains nuclei of tumor cells with translocation or amplification at BCL-1 locus

Mouse monoclonal antibodies were produced against the bacterial product encoded by human PRAD1/cyclin D1 gene, which is known to be involved in tumors with translocation or amplification at BCL-1 locus of 11q13. The immunizing antigens used were GST-PRAD1 and T7 gene 10-PRAD1 fusion products. Four antibodies were reactive with both PRAD1 fusion products and cell lysates of B-cell tumor cell lines with t(11;14)(q13;q32) and a breast cancer cell line with 11q13 amplification, on immunoblotting. An immunofluorescence study showed that only one of them stained nuclei of cells with 11q13 abnormalities. Since this antibody proved applicable for conventional paraffin-embedded tissue sections, immunohistologic staining of various lymphoma tissues was performed. Eight of 11 mantle cell lymphomas showed intermediate to strong positivity and 6 of the positive cases demonstrated characteristic staining patterns that were either predominantly nuclear or both nuclear and cytoplasmic. The nuclear staining pattern was not observed with other types of lymphoma and thus may correlate with PRAD1 mRNA overexpression.

Potentiation of long-term-cultured lymphokine-activated killer cell cytotoxicity against small-cell lung carcinoma by anti-CD3 x anti-(tumor-associated antigen) bispecific antibody

Lymphokine-activated killer (LAK) cells exhibit a potent cytotoxicity to malignant cells in vitro. However, a satisfactory effect has not been obtained in many clinical studies except for a few cases. One of the most important reasons why cytolytic activity could not be exhibited in vivo is that LAK cells do not accumulate in the tumor tissue because of a lack of specificity. In the present study, we show the effect of a bispecific antibody (bsAb) on the accumulation of LAK cells around the small-cell lung carcinoma (SCLC) cell and the subsequent enhancement of LAK cell cytotoxicity against SCLC. When short-term(4 days)-cultured LAK cells were used, OKT3 x LU246 bsAb, which direct CD3+ T-LAK cells to the target cell, induced a similar level of cytotoxicity to that induced by 3G8 x LU246 bsAb, which directs CD16+ LAK cells. Long-term(21 days)-cultured LAK cells exhibited a reduced spontaneous cytotoxicity but retained high cytotoxic activity, which could be directed by OKT3 x LU246 or 3G8 x LU246 bsAb. The inhibitory effect of LAK cells on tumor cell clonogenicity in soft agar was also enhanced by both bsAb. These results indicate that application of the therapy with LAK cells and OKT3 x LU246 bsAb to SCLC patients might be a promising new method of adoptive immunotherapy.

Detection of small-cell-lung-cancer cells in bone-marrow aspirates by monoclonal antibodies NCC-LU-243, NCC-LU-246 and MLuC1

We have used immunocytochemistry to identify tumor cells in bone-marrow aspirates of patients with small-cell lung cancer and we have compared the results with conventional histomorphology. The monoclonal antibodies (MAbs) used were NCC-LU-243 and NCC-LU-246 (cluster 1) and MLuC1 (cluster 6); 108 slides (52 patients) incubated with NCC-LU-246, 106 (51 patients) with NCC-LU-243 and 69 with MLuC1 (36 patients) were evaluated. Bone-marrow biopsies (83) were also obtained from 50 of these patients; 48/108 bone marrow aspirates were positive for cluster-1 antigen and 22/69 were positive for MLuC1. Immunocytochemistry with anti-NCAM MAbs detected bone-marrow localization in 38/83 bone-marrow aspirates compared with 9/83 bone-marrow biopsies, while MLuC1 was positive in 18/60 and bone-marrow biopsies in 6/60. Moreover, bone-marrow aspirates were positive for cluster-1 antigen in 7/17 patients with limited disease at diagnosis. Patients with positive bone-marrow biopsies had significantly shorter survival. No differences were found between patients with positive and those with negative marrow aspirates.

Detection of the neural cell adhesion molecule (NCAM) in serum of patients with small-cell lung cancer (SCLC) with "limited" or "extensive" disease, and bone-marrow infiltration

The neural cell adhesion molecule (NCAM) is a tumour-related antigen found on the surface of small-cell lung cancer (SCLC). NCAM exists in several molecular forms, including a soluble isoform. We have measured serum levels of NCAM using an enzyme immunoassay with 2 antibodies, NCC-LU-246 and NCC-LU-243, that react with different epitopes on the NCAM molecule. NCAM activity from 83 patients with active SCLC, either pre-treatment, progressing or in relapse was significantly higher than in 70 patients on follow-up. Overall, 40% of patients with active SCLC and 7% patients on follow-up had serum levels of NCAM > 2SD above controls; 61% of patients with relapsed SCLC had elevated levels of NCAM. Pre-treatment NCAM levels were significantly higher in 35 patients with "extensive" disease than in 19 patients with "limited" disease. Serum NCAM activity was also significantly higher in patients with tumour infiltration of the bone marrow. This difference could not be explained solely by the presence of "extensive" disease. Serum NSE levels in these patients were correlated with NCAM activity. The presence of raised serum NCAM in active disease and in patients in relapse suggests that this antigen could be used as a target for antibody-directed therapy of micrometastases.

Comparison of immunoreactivity between two different monoclonal antibodies recognizing peptide and polysialic acid chain epitopes on the neural cell adhesion molecule in normal tissues and lung tumors

A comparative immunohistochemical study of two different monoclonal antibodies against different epitopes on the neural cell adhesion molecule (N-CAM) was performed. Various normal tissues and lung tumors were examined for reactivity with NCC-LU-243, a monoclonal antibody which recognizes a peptide epitope on N-CAM, and monoclonal antibody 735 (MoAb 735), which reacts with a polysialic acid chain epitope on N-CAM. When acetone-fixed normal tissues were used, the immunoreactivities of MoAb 735 and NCC-LU-243 were not identical. In lung tumors, almost all small cell cancers (SCLC) and carcinoid tumors, and some non-SCLC were stained by both monoclonal antibodies. NCC-LU-243 stained the cell membrane only of almost all SCLC cells and clusters of non-SCLC cells. MoAb 735 stained the cell membrane of SCLC in a patchy manner and not only the cell membrane but also the cytoplasm of some non-SCLC. However cytoplasmic staining was evaluated as 'not positive'. The number of positive cases and the size of the positive tumor cell population determined by cell membrane staining with MoAb 735 were smaller than those determined with NCC-LU-243 in both SCLC and non-SCLC cases. In routinely formalin-fixed materials, the immunoreactivity of both monoclonal antibodies, especially of NCC-LU-243, decreased after prolonged fixation as in surgically resected and autopsy materials. However, both monoclonal antibodies were found to be useful when materials were fixed for a short period of time as in biopsy specimens.

Two monoclonal antibodies against small-cell lung cancer show existence of synergism in binding

Murine IgG1 monoclonal antibodies (mAbs), ITK-2 and ITK-3, were generated against a small-cell lung cancer (SCLC) cell line. Enzyme-linked immunosorbent assay using a variety of established cell lines as substrates, immunoperoxidase staining of freshly frozen tissue sections, and fluorescence-activated cell sorter analysis of peripheral blood leukocytes showed that these mAbs recognize a part of the SCLC-associated cluster 1 antigen. In immunoprecipitation studies, both ITK-2 and ITK-3 bound to a 145-kDa glycoprotein of SCLC cell membrane extracts, as did MOC-1 and NKH-1, which both recognize the cluster 1 antigen. However, because the binding of 125I-labeled ITK-2 to SCLC cells was not inhibited by MOC-1 or NKH-1, the binding site of ITK-2 on SCLC cells appeared to be different from that of either MOC-1 or NKH-1. Unexpectedly, binding of 125I-labeled ITK-2 to SCLC cells increased in the presence of ITK-3. This ITK-3-induced increase in ITK-2 binding was due partly to an increase in the number of binding sites for ITK-2 on SCLC cells. Addition of ITK-3 may, therefore, improve the effectiveness of ITK-2-based tumor detection or therapy.

Preservation of cluster 1 small cell lung cancer antigen in zinc-formalin fixative and its application to immunohistological diagnosis

Monoclonal antibodies reactive with cluster 1 small cell lung cancer antigen have been shown to be useful for the distinction of small cell from non-small cell tumours. In previous studies the antibodies have been applied to frozen sections and cold acetone-fixed tissues. However, one of three monoclonal antibodies that we produced, NCC-LU-243, reacted with some small cell lung carcinomas fixed in formalin solution and embedded in paraffin. The addition of zinc sulphate to the formalin solution at a concentration of 2% (v/w) greatly improved antigen immunoreactivity, and reactivity was retained even after prolonged fixation. Occasionally, immunoreactivity was present in a poorly differentiated adenocarcinoma with rosette-like structures. The monoclonal antibody NCC-LU-243 is thus of considerable potential value in the immunohistochemical diagnosis of small cell lung cancers.