(1/129) Motility-related protein (MRP-1/CD9) and KAI1/CD82 expression inversely correlate with lymph node metastasis in oesophageal squamous cell carcinoma.
Although the mechanisms of action of the transmembrane superfamilies, motility-related protein-1 (MRP-1/CD9) and KAI1/CD82, are not well known, they are reported to suppress the metastasis of several kinds of cancers. The suppression of cell motility by MRP-1/CD9 may cause suppression of the metastasis. As we could not find any reports concerning the expression of MRP-1/CD9 and KAI1/CD82 in oesophageal cancers we investigated their expression in oesophageal specimens. We conducted immunohistochemical staining for MRP1/CD9 against 108 cases of oesophageal squamous cell carcinoma using anti-MRP-1/CD9 monoclonal antibody M31-15, and for KAI1/CD82 against 104 cases using anti-KAI1/CD82 monoclonal antibody C33. To investigate the gradual expression of MRP-1/CD9 and KAI1/CD82, 24 oesophageal dysplasias were immunohistochemically stained using the same method and then investigated. The expression of both MRP-1/CD9 and KAI1/CD82 were positive on the cell membranes of normal oesophageal epithelial cells, but reduced or negative in the cancer cells. Reduced MRP-1/CD9 expressions significantly correlated to tumour depth (P = 0.0009). We found a significantly greater number of reduced or negative expression of MRP-1/CD9 and KAI1/CD82 in lymph node metastatic cases (P = 0.0003 and P= 0.0129, respectively), but not in distant metastatic cases. The 5-year survival rate of MRP-1/CD9-negative and reduced patients was significantly worse than those of positive patients (n = 108, curative cases, RO). Few cases remained KAI1/CD82-positive (9.6%; 10/104) in oesophageal cancer. Twenty (83.3%) and twenty-two (91.7%) cases out of 24 dysplasias were defined as KAI1/CD82-positive and MRP1/CD9-positive, respectively. The decrease in MRP-1/CD9 and KAI1/CD82 expression may facilitate lymph node metastasis in oesophageal squamous cell carcinomas. Knowing the status of the expression of MRP-1/CD9 appears helpful in predicting the prognosis for each patient. (+info)
(2/129) A novel molecular staging protocol for non-small cell lung cancer.
A molecular staging protocol using reliable markers is of importance in predicting the prognosis of patients with non-small cell lung cancer (NSCLC) and for instituting their appropriate post-surgical treatment. We analysed tumor tissues from 187 NSCLC patients. The DNA and mRNA were extracted from frozen specimens, and then polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and direct sequencing were performed to investigate mutations of p53 from exons 5-8, and mutations of K-ras at exon 1. To determine MRP-1/CD9 gene and KA11/CD82 gene expression, which have been postulated to be metastasis suppressor genes, we have applied quantitative RT-PCR. A Cox multivariate regression analysis showed that nodal status, MRP-1/CD9 and K-ras status were significant factors for prognosis (P<0.0001, P=0.0083 and P=0.0004, respectively). Based on these results, we classified the patients into three groups according to their MRP-1/ CD9 and K-ras status. Patients with both MRP-1/CD9 positive and wild K-ras tumors were defined as group A, patients with either reduced MRP-1/CD9 or mutant K-ras tumors were defined as group B and patients with both reduced MRP-1/CD9 and mutant K-ras tumors were designated as group C. This new classification was significantly correlated with the tumor status and pathological stage (P=0.0098 and P=0.0017, respectively). The overall survival rate of the group A patients was significantly better than the group B patients (59.6% vs 27.9%, P=0.0001) and also that of group B patients was better than the group C patients (27.9% vs 20.0%, P=0.0378). This tendency was also found in patients with 110 node-negative NSCLCs (A vs B vs C=75.8% vs 34.9% vs 0.0%, P<0.0001). A Cox multivariate regression analysis in NSCLC patients demonstrated that an evaluation for both MRP-1/CD9 expression and K-ras mutations had a significant prognostic effect as well as nodal status (P<0.0001). (+info)
(3/129) Motility inhibition and apoptosis are induced by metastasis-suppressing gene product CD82 and its analogue CD9, with concurrent glycosylation.
Metastasis-suppressing gene product CD82 and its analogue CD9 are considered to suppress the malignancy of various human cancers, although the rationale for this effect is unknown. The present study addresses phenotypic changes in Chinese hamster ovary mutant cell line ldlD deficient in UDP-Glc 4-epimerase and expressing CD82 or CD9 by cDNA transfection. Only CD82- or CD9-expressing cells grown in Gal-supplemented medium showed reduced motility and massive cell death, which are characteristic of apoptosis, after a latent period. Under this condition, endogenous GM3 synthesis was observed as a common factor, and N-glycosylation occurred at a high level in CD82 and to a lesser extent in CD9. Thus, the malignancy-suppressing effect of CD82 or CD9 is based partially on cell motility inhibition and apoptosis induction promoted by concurrent GM3 synthesis and N-glycosylation. (+info)
(4/129) Suppression of telomerase, reexpression of KAI1, and abrogation of tumorigenicity by nerve growth factor in prostate cancer cell lines.
Nerve growth factor (NGF) is expressed in the prostate, where it appears to be involved in the control of epithelial cell growth and differentiation. NGF production is decreased in prostate tumors. However, the role of this neurotrophin in the control of proliferation and progression of prostate cancers is still a matter of investigation. Prostate adenocarcinomas are telomerase-positive tumors. Chronic exposure of DU145 and PC3 prostate tumor cell lines to NGF resulted in a dramatic down-regulation of telomerase activity. This effect was correlated in terms of concentrations and time with a remarkable down-regulation of cell proliferation both in vitro and in vivo but was not secondary to NGF-induced quiescence. No down-regulation of telomerase activity was, in fact, detectable during serum starvation-induced quiescence. LNCaP cells, which do not express NGF receptors, appear to be insensitive to the actions of NGF. DU145 and PC3 cells do not express the KAI1 metastasis suppressor gene, which is present in the prostate and is progressively lost during the progression of prostate cancers. Chronic NGF treatment strongly induced the reexpression of this gene in these cell lines, and this effect was correlated with the suppression of their invasive potential in vitro. The data presented here suggest that NGF reverts two metastatic prostate cancer cell lines to slowly proliferating, noninvasive phenotypes characterized by a very low telomerase activity and by the expression of the KAI1 metastasis suppressor gene. (+info)
(5/129) Frequent loss of KAI1 expression in squamous and lymphoid neoplasms. An immunohistochemical study of archival tissues.
The metastasis suppressor gene KAI1 was identified by its ability to inhibit the formation of pulmonary metastases in experimental models for prostatic carcinoma. Down-regulation of this gene may be correlated with the invasive phenotype in melanomas and colon and bladder carcinomas and with the metastatic phenotype in carcinomas of the lung, breast, prostate, and pancreas. The goal of our study was to establish an immunohistochemical method to detect KAI1 expression in archival tissues. Using cell lines with known KAI1 levels and paraffin-embedded KAI1 positive tissues as controls, we observed strong membrane staining in lymphoid follicular centers and squamous epithelia. We then demonstrated the utility of our assay by studying KAI1 expression in 34 lymphoid and 57 squamous lesions. All eight reactive lymph nodes were KAI1 positive. In contrast, three of 13 follicular small cleaved and five of 13 diffuse large cell lymphomas were KAI1 negative. Seventy-nine percent (37 of 47) of invasive squamous cell carcinomas from the lung (n = 15), head and neck (n = 18), and cervix (n = 14) showed extensive KAI1 down-regulation. Loss of KAI1 expression was also found in a subset of 10 high-grade cervical dysplasias. Our data show that (i) immunohistochemistry is a suitable technique for evaluating KAI1 expression in archival tissues; (ii) KAI1 was not expressed in a subset of both low-grade and high-grade lymphomas; and (iii) there was extensive down-regulation of KAI1 in squamous cell carcinomas, suggestive of an important role of the gene in the suppression of invasion in these malignancies. (+info)
(6/129) Loss of KAI1 expression in the progression of colorectal cancer.
The transmembrane 4 superfamily member KAI1 (CD82) has been shown to inhibit pulmonary metastases in experimental metastasis models of prostate cancer and melanoma. KAI1 expression is decreased in the progression of common solid epithelial tumors of adulthood, including lung, prostate, breast, esophageal, gastric, pancreatic, and bladder cancers. The purpose of our study was to investigate KAI1 expression in the progression of human colorectal cancer. We first analyzed 20 colorectal cancer cell lines by immunoblot techniques. KAI1 was expressed heterogeneously, with the tumor cell lines having a more complex degree of glycosylation compared with that of the normal colonic tissue. KAI1 was highly expressed in the primary SW480 colon cancer cell line but was down-regulated 15-fold in the matched metastatic SW620 cell line. We also investigated KAI1 protein expression by immunohistochemistry in tissues from 84 patients with colorectal cancer. Each tissue section was assigned a KAI1 mean score (KMS) from 0 to 300 based on the product of the percentage of cells that stained for KAI1 and the intensity of the stain (1, 2, or 3). In 84 patients with colorectal cancer, KAI1 was expressed at high levels in normal colonic mucosa (KMS 226) but was expressed at lower levels in the primary tumors (KMS 65; P < 0.0001). In a subset of 12 patients with stage IV metastatic disease, we observed a progressive down-regulation of KAI1, from the normal adjacent colonic mucosa (KMS 193) to the primary tumor (KMS 72; P = 0.0001) to the liver metastasis (KMS 25; tumor compared with metastasis, P = 0.0135). We found no correlation between loss of KAI1 expression and stage of disease. In 10 patients, we also noted loss of KAI1 expression in the transition from normal colonic mucosa (KMS 237) to adenoma (KMS 174) to carcinoma (KMS 62; P < 0.0167 for all three comparisons). We conclude that the down-regulation of KAI1 occurs early in the progression of colorectal cancer. (+info)
(7/129) Importance of the major extracellular domain of CD9 and the epidermal growth factor (EGF)-like domain of heparin-binding EGF-like growth factor for up-regulation of binding and activity.
Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) is a member of the EGF family of growth factors. The membrane-anchored form of HB-EGF (proHB-EGF) is mitogenically active to neighboring cells as well as being a precursor of the soluble form. In addition to its mitogenic activity, proHB-EGF has the property of binding to diphtheria toxin (DT), serving as the specific receptor for DT. Tetramembrane-spanning protein CD9, a member of the TM4 superfamily, is physically associated with proHB-EGF at the cell surface and up-regulates both mitogenic and DT binding activities of proHB-EGF. To understand this up-regulation mechanism, we studied essential regions of both CD9 and proHB-EGF for up-regulation. Immunoprecipitation experiments revealed that not only CD9 but also other TM4 proteins including CD63, CD81, and CD82 associate with proHB-EGF on the cell surface. However, these TM4 proteins did not up-regulate DT binding activity of proHB-EGF. Transfection of a series of chimeric constructs comprising CD9 and CD81 showed that the major extracellular domain of CD9 is essential for up-regulation. Assays of DT binding activity and juxtacrine mitogenic activity of the deletion mutants of proHB-EGF and chimeric molecules, derived from proHB-EGF and TGF-alpha, showed that the essential domain of proHB-EGF for up-regulation is the EGF-like domain. These results indicate that the interaction of the extracellular domains of both molecules is important for up-regulation. (+info)
(8/129) Absence of p53-dependent induction of the metastatic suppressor KAI1 gene after DNA damage.
The p53 tumor suppressor protein functions to monitor the integrity of the genome. If a damage is detected, p53 binds tightly to specific sequence elements in the DNA and induces the transactivation of genes involved in various growth regulatory processes such as cell cycle progression, DNA repair and apoptosis. A p53-binding site was recently identified in the promoter region of the metastatic suppressor KAI1 gene, suggesting that this gene was a direct transcriptional target of p53. To test the relevance of this hypothesis, we studied the endogenous KAI1 expression in a series of human cell lines with varying p53 status in response to genotoxic treatment as well as in different cellular models exhibiting an inducible p53 activity. Overall, our data indicate that KAI1 expression is not significantly modulated by p53. This observation provides a direct evidence that the presence of a p53-binding site in regulatory domains is not a sufficient criteria to define a p53-transcriptional target gene. (+info)