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Biomedical subjects

N H Bander

Publications and source records attributed to N H Bander.

At least 37 records · Page 2Linked to original sources
PubMed1999

Reduced expression of beta-subunit of Na,K-ATPase in human clear-cell renal cell carcinoma.

PURPOSE: Multiple subtypes of renal cancer have been identified. Clear-cell renal cell carcinoma (RCC) is the most common subtype of RCC and one of the more aggressive. The goal of this study was to investigate in RCC the levels of Na,K-ATPase, an abundant enzyme in the kidney which is crucial for various kidney functions. Na,K-ATPase is a heterodimer consisting of a catalytic a-subunit and a glycosylated beta-subunit whose function is still not well-defined. MATERIALS AND METHODS: Fourteen clear-cell RCC specimens were studied. The levels of the Na,K-ATPase alpha and beta-subunits in normal kidney and RCC tissues were determined by immunoblot analysis. The localization of the alpha and beta-subunits was studied by immunofluorescence and laser scanning confocal microscopy. Na,K-ATPase activity was determined using a coupled-enzyme spectrophotometric assay. RESULTS: In normal kidney, the cells demonstrate an epithelial morphology with distinct basolateral plasma membrane localization of the alpha and beta-subunits. Conversely, the cells of the clear-cell RCC have lost their epithelial phenotype and the alpha and beta-subunits show a diffuse intracellular staining. Clear-cell RCC tumor cell lysates showed a consistent 95.6+/-2.8% (mean +/- SD) reduction in protein levels of beta-subunit relative to the levels in normal kidney. The alpha-subunit level in RCC lysates was generally near or above the levels relative to normal kidney. The reduced beta-subunit expression was accompanied by a significant reduction in the Na,K-ATPase activity in RCC membranes. CONCLUSIONS: These results suggest that the beta-subunit may regulate the Na,K-ATPase activity in vivo. Diminished Na,K-ATPase activity in conjunction with the reduced beta-subunit level is associated with the clear-cell RCC phenotype.

Adult↗
PubMed1998

Constitutive and antibody-induced internalization of prostate-specific membrane antigen.

Prostate-specific membrane antigen (PSMA) is a cell surface glycoprotein expressed predominantly by prostate cancer cells. We have characterized four monoclonal antibodies that bind to the extracellular domain of PSMA (Liu et al., Cancer Res., 57: 3629-3634, 1997). Here we report that viable LNCaP cells internalize these antibodies. Laser scanning confocal microscopy reveals that the internalized antibodies accumulate in endosomes, and immunoelectron microscopy reveals that endocytosis of the PSMA-antibody complex occurs via clathrin-coated pits. In addition, a quantitative cell surface biotinylation assay demonstrates that PSMA is constitutively endocytosed in LNCaP cells and that anti-PSMA antibodies increase the rate of internalization of PSMA. These studies suggest that PSMA might function as a receptor mediating the internalization of a putative ligand. The availability of prostate-specific internalizing antibodies should aid the development of novel therapeutic methods to target the delivery of toxins, drugs, or short-range isotopes specifically to the interior of prostate cancer cells.

Antibodies, Monoclonal↗
PubMed1998

Aminopeptidase A expression and enzymatic activity in primary human renal cancers.

The gp160 human kidney differentiation antigen is identical to human aminopeptidase A (APA), a zinc-dependent cell-surface metallopeptidase which hydrolyzes peptides with N-terminal acidic residues. GP160/APA is constitutively expressed by proximal tubule cells, the normal cellular counterpart of most renal cancers (RCs). Immunohistochemical analysis of gp160/APA protein expression in 62 primary renal tumor specimens using monoclonal antibody S4 revealed heterogeneous or homogeneous expression of gp160/APA in 46/51 (90%) of clear cell carcinomas in contrast with 1/8 (13%) papillary renal tumors and 0/3 oncocytomas (p<0.001). Analysis of five primary clear cell carcinomas for gp160 protein expression immunohistochemically and associated APA catalytic activity revealed one tumor which expressed gp160/APA protein which was enzymatically inactive. Direct sequence analysis of DNA derived from this specimen could not detect mutations within the zinc-binding domain which would eliminate gp160/APA catalytic activity. These data indicate that the gp160/APA protein is expressed by primary clear cell but not papillary RCs or oncocytomas, and that alterations in gp160/APA protein including loss of protein expression or enzymatic activity occur in 20% of primary clear cell RCs.

Adenoma, Oxyphilic↗
PubMed1998

Phase I/II radioimmunotherapy trial with iodine-131-labeled monoclonal antibody G250 in metastatic renal cell carcinoma.

This Phase I/II radioimmunotherapy study was carried out to determine the maximum tolerated dose (MTD) and therapeutic potential of 131I-G250. Thirty-three patients with measurable metastatic renal cell carcinoma were treated. Groups of at least three patients received escalating amounts of 1311I (30, 45, 60, 75, and 90 mCi/m2) labeled to 10 mg of mouse monoclonal antibody G250, administered as a single i.v. infusion. Fifteen patients were studied at the MTD of activity. No patient had received prior significant radiotherapy; one had received prior G250. Whole-body scintigrams and single-photon emission computed tomography images were obtained in all patients. There was targeting of radioactivity to all known tumor sites that were > or =2 cm. Reversible liver function test abnormalities were observed in the majority of patients (27 of 33 patients). There was no correlation between the amount of 131I administered or hepatic absorbed radiation dose (median, 0.073 Gy/mCi) and the extent or nature of hepatic toxicity. Two of the first six patients at 90 mCi/m2 had grade > or =3 thrombocytopenia; the MTD was determined to be 90 mCi/m2 131I. Hematological toxicity was correlated with whole-body absorbed radiation dose. All patients developed human antimouse antibodies within 4 weeks posttherapy; retreatment was, therefore, not possible. Seventeen of 33 evaluable patients had stable disease. There were no major responses. On the basis of external imaging, 131I-labeled mouse monoclonal antibody G250 showed excellent localization to all tumors that were > or =2 cm. Seventeen of 33 patients had stable disease, with tumor shrinkage observed in two patients. Antibody immunogenicity restricted therapy to a single infusion. Studies with a nonimmunogenic G250 antibody are warranted.

Adult↗
PubMed1998

Mouse-human chimeric anti-epidermal growth factor receptor antibody C225 inhibits the growth of human renal cell carcinoma xenografts in nude mice.

The epidermal growth factor (EGF) receptor and its ligand transforming growth factor-alpha (TGF-alpha) are overexpressed in human renal cell carcinoma (RCC). The chimeric anti-EGF receptor monoclonal antibody C225 was used to determine the effects of blocking the EGF receptor on RCC growth both in vitro and in vivo. A panel of RCC cell lines all tested positive at various levels for EGF receptor cell surface expression. C225 inhibited DNA synthesis of cultured A498, Caki-1, SK-RC-4, SK-RC-29, and SW839 cells in a dose-dependent manner, ranging from 20 to 45% inhibition compared with untreated controls. C225 also inhibited exogenous ligand-stimulated tyrosine phosphorylation of EGF receptor on RCC cells. The antitumor effects of C225 on RCC tumor growth were evaluated in ascites, s.c., and orthotopic RCC xenograft models. Mice treated with C225 in a Caki-1 ascites xenograft model showed a significant increase in survival (P = 0.002). All control mice died with ascites tumors by week 9, whereas >70% of C225-treated mice survived beyond 12 weeks. C225 also inhibited the growth of s.c. SK-RC-29 tumors in a dose-dependent manner. Mice treated with C225 (1 mg/dose) displayed a significant decrease in tumor volume compared with mice treated with control antibody (P < 0.05) or vehicle alone (P < 0.01). Lastly, C225 inhibited the growth and metastasis of RCC tumors growing orthotopically in the renal subcapsule of nude mice. Histological examination of RCC tumors from mice treated with C225 showed a substantial decrease in proliferating cell nuclear antigen staining and an increase in tumor cell apoptosis. These data suggest that C225 affects growth of RCC tumors by inhibiting EGF receptor-dependent proliferation and demonstrate the potential for therapeutic application of C225 in the treatment of human renal cancer.

Animals↗
PubMed1997

MHC class I and II expression in prostate carcinoma and modulation by interferon-alpha and -gamma.

BACKGROUND: Expression of Major Histocompatibility Complex (MHC) class I and II antigens are critical for the cellular immune response. Loss of MHC expression represents one mechanism by which cancer cells escape immune recognition. PURPOSE: To define MHC class I and II expression by prostate cancer (PCa) in vivo and in vitro and the ability to modulate MHC expression in vitro with IFN-alpha and -gamma. METHODS: Frozen tissue sections of 25 benign prostatic hyperplasia (BPH) and 18 PCa specimens were studied by immunohistochemistry. PCa cell lines LNCaP, PC-3, and DU-145 were studied by FACS, ELISA, and cytospin. Class I was detected by monoclonal antibody (mAb) W6/32, and class II by mAb 13.17. The effects of IFN-alpha and -gamma were assessed by testing the three cell lines in the presence or absence of varying concentrations of the cytokine for varying incubation times. RESULTS: Class I was strongly expressed by 24/25 BPH specimens; 4/18 (22%) PCa were homogeneously class I-positive, while 5/18 (28%) were heterogeneously positive and 9/18 (50%) were class I-negative. PC-3 and DU-145 expressed normal levels of class I, while LNCaP expressed only low levels. All line except LNCaP demonstrated significant up-regulation of class I with either IFN-alpha or -gamma. Class II expression was not seen in BPH epithelium nor in 17/18 PCa. Class II could be only weakly induced in the three PCa lines. CONCLUSIONS: These findings confirm prior studies demonstrating that class I expression is commonly lost or diminished in PCa. In addition, class II up-regulation by IFN-gamma appears very limited in relation to other normal or neoplastic epithelium. IMPLICATIONS: The present findings, taken together with previous studies, are most consistent with the expression of neoantigens by PCa, which are recognized and appropriately eliminated by the cellular immune system. This selective pressure favors outgrowth of cells which down-regulate or lose class I and/or class II expression. Understanding PCa immunobiology will help in the development of effective immunotherapy for this disease.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Monoclonal antibodies to the extracellular domain of prostate-specific membrane antigen also react with tumor vascular endothelium.

Prostate-specific membrane antigen (PSMA), initially defined by monoclonal antibody (mAb) 7E11, is a now well-characterized type 2 integral membrane glycoprotein expressed in a highly restricted manner by prostate epithelial cells. 7E11 has been shown to bind an intracellular epitope of PSMA that, in viable cells, is not available for binding. Herein, we report the initial characterization of the first four reported IgG mAbs that bind the external domain of PSMA. Competitive binding studies indicate these antibodies define two distinct, noncompeting epitopes on the extracellular domain of PSMA. In contrast to 7E11, these mAbs bind to viable LNCaP cells in vitro. In addition, they show strong immunohistochemical reactivity to tissue sections of prostate epithelia, including prostate cancer. These mAbs were also strongly reactive with vascular endothelium within a wide variety of carcinomas (including lung, colon, breast, and others) but not with normal vascular endothelium. These antibodies should prove useful for in vivo targeting to prostate cancer, as well as to the vascular compartment of a wide variety of carcinomas.

Animals↗
PubMed1997

Expression of the tumor-associated gene MN: a potential biomarker for human renal cell carcinoma.

MN is a novel cell surface antigen originally detected in human HeLa cells. Although it is also expressed in normal gastric mucosa, this antigen was previously found to be expressed in cells with a malignant phenotype in certain tissues of the female genital tract (cervix and ovary). Using an oligonucleotide primer set specific for MN-complimentary DNA, we performed reverse transcription-PCR assays on RNAs extracted from human cell lines and tissues to evaluate whether this marker might be expressed at other sites. RNA libraries extracted from normal human heart, lung, kidney, prostate, peripheral blood, brain, placenta, and muscle were negative for MN expression. RNAs extracted from liver and pancreatic tissue were positive for MN expression. Three of six renal cancer cell lines tested revealed MN expression. In addition, 12 of 17 samples of human renal cell carcinoma tissue tested positive for MN, all 12 of which were clear cell adenocarcinomas. This survey identified a unique association of MN expression with renal cell cancers, especially those of the clear cell variety, suggesting that MN is a potential marker for the diagnosis, staging, and therapeutic monitoring of renal cell carcinoma in humans.

Antigens, Neoplasm↗
PubMed1997

A multicenter trial evaluation of the fibrin/fibrinogen degradation products test for detection and monitoring of bladder cancer.

PURPOSE: Presently there is a lack of effective, noninvasive tests for the detection and monitoring of bladder cancer. Measurement of fibrin/fibrinogen degradation products in urine has been shown to be a useful indicator of bladder carcinoma. The objective of this study was to evaluate the AuraTek FDP rapid immunoassay device for the detection of urinary fibrin/ fibrinogen degradation products associated with bladder cancer. MATERIALS AND METHODS: A prospective multicenter study was conducted to compare AuraTek FDP with urinary cytology and hemoglobin dipstick for the detection of bladder cancer in 192 patients with a history of bladder cancer. RESULTS: AuraTek FDP was significantly more sensitive (68%) than conventional urinary cytology (34%, p < 0.001) or hemoglobin dipstick (41%, p < 0.001) in the detection of bladder tumors, particularly for low stage low grade disease. In subjects with invasive disease (T2-T4) the AuraTek FDP test had a sensitivity of 100%. Specificity of AuraTek FDP was 96% for healthy subjects, 86% in patients with urological disease other than bladder cancer and 80% for patients under surveillance for bladder cancer but with a negative cystoscopic finding at the time of assay. CONCLUSIONS: This simple, rapid (less than 7 minutes) point of care test is superior to conventional urine cytology and hemoglobin dipstick as an aid in the detection of bladder cancer.

Aged↗
PubMed1996

Major histocompatibility complex class I and class II expression in renal cell carcinoma and modulation by interferon gamma.

PURPOSE: To determine the expression of MHC class I and II in human renal cancer. MATERIALS AND METHODS: We analyzed tissue sections from 22 primary and 28 metastatic renal cell carcinomas (RCC), as well as 31 established RCC cell lines. Tissue specimens from normal kidney and cell cultures of normal kidney epithelium were also studied. In addition, MHC antigen expression on RCC cell lines was assessed both before and after incubation with human recombinant interferon gamma (IFN-gamma). Antigen expression was determined by mixed hemadsorption, indirect immunofluorescence, fluorescence activated cell sorting (FACS) or immunoperoxidase staining using the monoclonal antibodies (mAbs) W6/32 (anti-MHC class I), mAbs NAMB-1 and BBM.1 (anti-beta-2 microglobulin), and mAbs L243 and 13-17 (anti-MHC class II) antibodies. Soluble beta-2 microglobulin in conditioned medium was measured by ELISA. RESULTS: Normal renal epithelial cells, both in vivo and in vitro, showed low level expression of class I antigens. Immunohistochemical staining for MHC class II was limited to some proximal tubular cells, while cultured renal tubular cells were uniformly class II negative. The tumor cell populations in all 22 primary and in 26 of 28 (93%) metastatic RC specimens consisted predominantly of class I positive cells. Half of the samples from primary and metastatic tumors were class II negative. Incubation of RCC cell lines with IFN-gamma enhanced the expression of MHC class I, beta-2 microglobulin and class II. The upregulation of MHC expression was time and dose dependent and associated with increased release of soluble beta-2 microglobulin. CONCLUSIONS: (i) Like normal kidney, virtually all primary human renal cell carcinomas express MHC class I antigens and retain this phenotype even during tumor progression and metastasis; (ii) class II expression on normal and RCC cells appears more limited but occurs frequently in both primary and metastatic lesions; and (iii) in most continuous RCC cell lines expression of MHC class I and II can effectively be stimulated by IFN-gamma. Since expression of MHC molecules might determine the immunogenicity of human RCC, its constitutive expression and augmentation could play an important role for the immunotherapy and prognosis of human renal cancer.

Carcinoma, Renal Cell↗
PubMed1995

Reactivities of mouse monoclonal antibody K2.7 to renal cancers in complement dependent cytotoxicity and antibody dependent cell-mediated cytotoxicity.

Immunohistochemical analysis by indirect immunoperoxidase staining demonstrated that monoclonal antibody (mAb) K2.7, derived from a mouse immunized with a renal cell carcinoma (RCC) cell line OS-RC-2, reacted with 89 of 95 renal cancer tissues (94%). Only 1 gastric and uterine cancer tissue showed positive staining among 87 cancer specimens from 9 different organs. Among normal human tissues, the renal tubule, testis, epithelium of the uterine endometrial gland and Fallopian tube, grey matter of cerebrum and cerebellum, and foreskin showed positive staining. Serological analysis by protein A mixed hemadsorption (PA) assay demonstrated that mAb K2.7 reacted with 25 of 31 RCC cell lines (81%), but with only 2 of 50 other cell lines from different organs. The specific antitumor activities of mAb K2.7 against RCC cell lines were investigated in vitro by complement dependent cytotoxicity (CDC) and antibody dependent cell-mediated cytotoxicity (ADCC) assays. In the CDC assay, all of the 9 RCC cell lines reactive serologically with mAb K2.7 were killed by mAb K2.7 with normal human serum, and the killing activity of mAb K2.7 correlated well with the reactivity of mAb K2.7 in the PA assay. mAb K2.7 showed the same killing activity against each of 3 RCC cell lines with sera from 9 patients with low and high stage renal cancers, as well as with normal human serum. In the ADCC assay, mAb K2.7 with peripheral blood leukocytes (PBLs) from 4 healthy donors showed cytotoxic activity against RCC cell lines. Peripheral blood leukocytes from the same 9 renal cancer patients also showed significant killing activity against the 3 RCC cell lines. These findings suggest the potential utility of mAb K2.7 for specific immunotherapy of renal cancer.

Animals↗
PubMed1995

Cytotoxicity of gallium nitrate in vitro using bladder cancer cells.

BACKGROUND: Gallium nitrate has been used systemically for some malignancies in clinical trials. Because bladder cancer has many transferrin (Tf) receptors and gallium has been reported to bind avidly with Tf receptors, gallium cytotoxicity and the possibility of intravesical instillation therapy with gallium nitrate were studied in vitro. METHODS: The bladder cancer cell lines J82, 639V, VMCuB1, SCaBER, and 5637 were used. The amount of Tf receptor was checked by a rosette assay. As a cytotoxicity assay, two experimental models were tested using two or 72 hours of exposure to gallium solution. A gallium release study using 67Ga was done to investigate the movement of incorporated gallium. RESULTS: J82 had the most and SCaBER had the least Tf receptors. For 72 hours of exposure at gallium concentrations above 250 mumol/L, the inhibitory effect was a function of gallium concentration, and 100% cytotoxicity occurred at 2 mmol/L. At lower concentrations of gallium, the effect was related to the amount of Tf and the level of Tf receptor expression of the cells. With two hours of exposure, which was assumed to be a model of intravesical therapy, the inhibitory effect increased in proportion to gallium concentration and the frequency of treatment. Twenty mmol/L gallium effectively inhibited the growth in two hours of exposure. CONCLUSIONS: Intravesically administered gallium might be an effective therapy for bladder cancer, because its cytotoxicity is determined not by the amount of Tf receptor but by the gallium concentration and the duration of gallium exposure.

Antineoplastic Agents↗
PubMed1994

Current status of monoclonal antibodies for imaging and therapy of prostate cancer.

It is clear that there is significant need for improved staging and therapy of prostate cancer. The attributes and strengths of MoAbs seem particularly well-suited to the setting of prostate cancer. Recent progress in the application of MoAbs to in vivo imaging and therapy is encouraging. Clearly, further such efforts in prostate cancer are warranted.

Antibodies, Monoclonal↗
PubMed1993

Region-specific methylation of the parathyroid hormone-related peptide gene determines its expression in human renal carcinoma cell lines.

Tumor production of a parathyroid hormone-related peptide (PTHrP) is a common cause of the syndrome of humoral hypercalcemia of malignancy, which is frequently associated with renal cell carcinomas. Why certain renal cell carcinomas produce PTHrP while others do not is unknown. Using a system of 12 human renal carcinoma cell lines which either do (n = 6) or do not (n = 6) produce PTHrP, we found that the expression of the PTHrP gene in these cell lines is controlled at the transcriptional level. Transfection studies failed to demonstrate variation in PTHrP promoter activity in these cell lines sufficient to account for the differential PTHrP expression, implicating a cis-acting mechanism. Transcription of the PTHrP gene in these cell lines was found to correlate with the methylation state of specific CpG dinucleotides located within the promoter region but outside a CpG island. The functional importance of this mechanism of control was confirmed by the ability of the demethylating agent, 5-azacytidine, to induce PTHrP mRNA expression in previously nonexpressing cell lines.

Azacitidine↗
PubMed1993

Interleukin-10 production by human carcinoma cell lines and its relationship to interleukin-6 expression.

Recent data indicate a major role for IL-10 in suppressing immune and inflammatory reactions. To date, expression of human IL-10 has been attributed primarily to helper T lymphocytes, activated monocytes, and neoplastic B cells, and was often found to be associated with IL-6 expression. In this study we sought to determine whether non-hematopoietic human tumor cell lines produce IL-10 and, if so, what is the relationship between IL-10 and IL-6. Using ELISA, we determined IL-10 and IL-6 levels in culture supernatants of 48 cell lines established from carcinomas of the kidney, colon, breast and pancreas, malignant melanomas and neuroblastomas. IL-6 protein was secreted by 28 of the tumor cell lines; IL-10 was measurable in 15 cell lines. IL-6 secretion was maximal and most frequent in renal-cancer cell lines, while IL-10 production was found to be highest and most common among cell lines derived from colon carcinomas. IL-10 in conditioned medium of one of the colon carcinoma cell lines (CCL222) was bio-active, as demonstrated in the mouse MC/9 mast-cell-line assay and in human mixed-lymphocyte reactions. In both assays, IL-10 bio-activity was neutralized by an anti-IL-10 monoclonal antibody. Expression of IL-6 and IL-10 was confirmed by RNA analysis using message amplification by PCR and sequencing of amplified cDNA. LPS, IL-1 alpha, and TNF-alpha strongly enhanced the release of IL-6 by RCC cells, but only marginally affected IL-10 production in colon-carcinoma cells. IL-10 secretion by colon-carcinoma cells was moderately stimulated by IFN-gamma and IL-4. Dexamethasone suppressed the release of IL-6, but had no inhibitory effect on IL-10 secretion. Our results demonstrate that tumor cell lines established from certain types of human carcinomas are capable of expressing and releasing IL-6 and/or IL-10, suggesting a role of these cytokines in solid-tumor development and anti-tumor immunity.

Animals↗
PubMed1993

Molecular cloning of the human kidney differentiation antigen gp160: human aminopeptidase A.

gp160 is a cell surface differentiation-related glycoprotein of 160 kDa expressed by epithelial cells of the glomerulus and proximal tubule cells of the human nephron but only by a subset of renal cell carcinomas (RCCs). We have reported that gp160 expression correlates with the resistance of cultured RCCs to the antiproliferative effects of alpha interferon, while lack of expression correlates with sensitivity to alpha interferon. In this study, we have purified gp160 protein, obtained partial sequences of random peptides, and isolated a full-length cDNA. The gp160 cDNA possesses 78% homology to the murine BP-1/6C3 antigen, a B-lymphocyte differentiation protein that exhibits aminopeptidase A (APA; EC 3.4.11.7) activity. Enzymatic assays on human RCC cell lines indicated a 100% concordance between APA activity and gp160 expression. APA activity of gp160-expressing RCC cells was increased or decreased by a panel of APA activators or inhibitors, respectively. Furthermore, anti-gp160 monoclonal antibodies immunoprecipitate APA activity from RCC cell lysates and selectively deplete APA activity from RCC cell extracts. These data indicate that the gp160 human kidney/RCC glycoprotein is human APA.

Amino Acid Sequence↗