Neutral endopeptidase 24.11 loss in metastatic human prostate cancer contributes to androgen-independent progression.

Neutral endopeptidase 24.11 (NEP) is a cell-surface enzyme expressed by prostatic epithelial cells that cleaves and inactivates neuropeptides implicated in the growth of androgen-independent prostate cancer (PC). We report that NEP expression and catalytic activity are lost in vitro in androgen-independent but not androgen-dependent PC cell lines. In vivo, NEP protein expression is commonly decreased in cancer cells of metastatic PC specimens from patients with androgen-independent but not androgen-dependent PC. Overexpression of NEP in androgen-independent PC cells or incubation with recombinant NEP inhibits PC cell growth. Furthermore, in androgen-dependent PC cells, expression of NEP is transcriptionally regulated by androgen and decreases with androgen withdrawal. These data suggest that decreased NEP expression, common in androgen-independent PCs, is facilitated by the elimination of androgens, and that NEP loss plays an important role in the development of androgen-independent PC by allowing PC cells to use mitogenic neuropeptides as an alternate source to androgen in order to stimulate cell proliferation.

Retroviral vector-mediated lymphokine gene transfer into human renal cancer cells.

Effective vaccination against cancer, either for prophylaxis or therapy, has been an elusive goal for years. Cytokine gene therapy offers a novel approach to generate immunogenic tumor cell vaccines. To examine the feasibility of cytokine gene transfer into human renal cancer (RC) cells, we introduced the cDNAs for human interleukin-2 (IL-2) or interferon-gamma (IFN-gamma) into various RC cell lines with retroviral vectors. Using the NIH3T3 amplification assay, no replication competent retroviral particles were detectable in cell culture supernatants taken from gene-modified RC cell lines. Efficient expression of both lymphokines was achieved. Depending on the cell line and the vector construct used, lymphokine gene-modified human RC cell lines released 4 to 29 units/10(6) cells of IL-2, or up to 10 units/10(6) cells of IFN-gamma within 48 h. Fluorescence-activated cell sorter analysis of SK-RC-29 cells releasing IFN-gamma showed increased expression of major histocompatibility complex class I antigen, beta 2-microglobulin, and ICAM-1, as well as induction of major histocompatibility complex class II antigen expression [human leukocyte antigen(HLA)-DR, -DP], but no changes in these cell surface markers were observed with SK-RC-29 cells releasing IL-2. Following in vitro gamma-irradiation with 5,000 or 10,000 rad, growth of lymphokine gene-modified RC cells was abrogated, but their capability to release lymphokine and express lymphokine-induced antigenic determinants, such as HLA-DR, was retained. Tumor formation by the human RC cell line SK-RC-29 in BALB/c nude mice was not affected by IFN-gamma secretion, but was inhibited by in vivo release of IL-2 from s.c. injected tumor cells. These studies demonstrate the feasibility of retroviral mediated lymphokine-gene transfer into human RC cells and suggest a means for generating autologous or HLA-matched allogeneic tumor cell vaccines for the treatment of patients with renal cell carcinoma.

Establishment and characterization of human renal cancer and normal kidney cell lines.

We have reviewed our laboratory's efforts to establish continuous human renal cancer cell lines. During the 16-year period of 1972 through 1987, 498 successive attempts resulted in establishment of 63 renal cancer cell lines. Of these lines, 46 were derived from primary kidney tumors and 17 from metastatic sites (lung, brain, bone, and lymph node). Forty-three of these lines have been characterized with regard to morphology, growth kinetics, anchorage-independent growth, tumorigenicity in athymic nude mice, and expression of kidney cell surface antigens. These results were compared with data from primary short term cultures of normal kidney epithelium. The overall success rate of establishing continuous renal cancer cell lines was 12.7%. In general, no significant difference in success was noted based on whether the specimen was derived from a primary or a metastatic lesion. However, all successfully established lines were derived from tumors exhibiting clinically "aggressive" behavior. All cell lines expressed proximal tubular cell differentiation antigens. Significant morphological heterogeneity was observed among normal kidney as well as kidney cancer cell lines in vitro. No significant difference in doubling time was found between cell lines of renal cancer and passage 1 cultures of normal kidney epithelium. Twenty-one of 30 (70%) lines assayed formed clones on soft agar and 26 of 33 (79%) lines grew in athymic mice. Among the 25 lines which were assayed for both soft agar growth and tumorigenicity in nude mice, this pair of phenotypic traits were concordant in 17 lines (60%). Four lines (16%) grew on agar but not in mice, while four other lines (16%) failed to grow in agar but were tumorigenic in mice.

Blood group-related antigens in human kidney: modulation of Lewis determinants in renal cell carcinoma.

Seven mouse monoclonal antibodies and the lectin Ulex europaeus, detecting blood group related antigens of the ABH and Lewis systems, have been used to determine the immunophenotype of human renal cell carcinomas. Immunohistochemical analyses have demonstrated that these antigenic systems are differentially expressed by distinct normal cell types and domains of the human nephron. In the present study we analyzed the immunophenotype of 29 primary and 15 metastatic renal carcinomas by the immunoperoxidase method. Blood type was known in all of the cases and secretor status in nine cases. ABH specificities were not detected in tumor cells of the primary tumors studied, although two of the metastases showed heterogeneous expression of H and A antigens, respectively. Lewisx (Lex) determinant was detected in 76% of primary renal cell carcinomas; however, Lex was only expressed by occasional cells in 20% of the metastatic tumors analyzed. Lewisa (Lea) was detected with a heterogeneous pattern of expression in 31% of the primary and 26% of the metastatic renal tumors studied. Lewisy (Ley) antigen expression was found in 17% of the primary and 20% of the metastatic tumors analyzed. Detection of precursor type 1 structure was observed in 28% of primary and 20% of metastatic renal cell carcinomas. The present study suggests the histogenesis of renal cell carcinoma in the proximal nephron, based on the expression of Lex and Lea antigens. It also shows: (a) an apparent deletion, downregulation or structural modification of Lex determinant in most of the metastatic tumors; (b) undetectable levels of ABH specificities in tumor cells of primary renal cell carcinoma; and (c) enhanced expression and/or neosynthesis of precursor type 1 structure and Ley determinant in some renal cell carcinomas.

Analysis of a mouse monoclonal antibody that reacts with a specific region of the human proximal tubule and subsets renal cell carcinomas.

Murine monoclonal antibody (mAb) F31 detects a heat-stable antigen (URO-8) found in the acidic lipid fraction of renal cancer cell extracts. Serological analysis of mAb F31 reactivity was assayed on 176 human cell lines. mAb F31 reacted with 38 of 45 renal cancers, a subpopulation of cells in primary cultures of normal renal epithelia, and two of 13 colon, two of 15 lung, and four of five ovarian cancers. No other epithelial, hematopoietic, or neuroectodermal cell lines tested were reactive. Immunofluorescence and immunoperoxidase analyses of fresh frozen tissue sections revealed mAb F31 reactivity in kidney, gastrointestinal tract, biliary canaliculi, bronchial epithelium, and skin. Within the kidney, mAb F31 immunoreactivity was confined to the straight portion of the proximal tubule. A panel composed of previously characterized mAbs as well as mAb F31 defines the antigenic phenotype of proximal convoluted tubular cells as URO-2+/URO-3+/URO-4+/URO-10+/URO-8-/URO-5-; proximal straight tubular cells as URO-2+/URO-3+/URO-4+/URO-10-/URO-8+/URO-5-; and cells of the descending thin limb of Henle as URO-2-/URO-3+ or -/URO-4+/URO-10-/URO-8-/URO-5+. While adult proximal tubular cells demonstrated reciprocal expression of URO-8 and URO-10, fetal kidney proximal tubule progenitor cells coexpressed both antigens (URO-10+/URO-8+). Fifty renal cancer specimens were typed with these antibodies. Fourteen cases were URO-10+/URO-8-, ten cases were URO-10-/URO-8+, and 25 cases expressed both antigens (URO-10+/URO-8+). These phenotypes are consistent with derivation of these particular subsets from the proximal convoluted tubule, the pars recta, or a proximal tubule progenitor cell, respectively. Only one specimen failed to express either URO-8 or URO-10.

Quantitative analysis of antibody localization in human metastatic colon cancer: a phase I study of monoclonal antibody A33.

A33 is a mouse immunoglobulin G2a (IgG2a) monoclonal antibody (mAb) that detects a heat-stable, protease- and neuraminidase-resistant epitope. The antigen is homogeneously expressed by virtually all colon cancers and in the colon mucosa but not other epithelial tissues. The biodistribution and imaging characteristics of iodine-131 (131I)-mAbA33 were studied in colorectal carcinoma patients with hepatic metastases. Antibody labeled with 2 to 5 mCi of 131I was administered intravenously (IV) 7 to 8 days before surgery at five dose levels, ranging from 0.2 mg to 50 mg, with three or more patients entered at each dose level. In addition, three patients received 2 mg 131I-mAbTA99 (an isotype-matched control mAb) together with 125I-mAbA33. Evaluation included whole-body imaging with a gamma camera, technetium-99 (99mTc)-human serum albumin blood pool scans, liver/spleen scans, abdominal computed tomographic (CT) scans, hepatic arteriograms, antibody pharmacokinetics, and assessment of antibody distribution in biopsied malignant and normal tissues. Selective mAbA33 localization to tumor tissue was demonstrated in 19 of 20 patients, and external imaging correlated with surgical inspection, pathologic examination, and tissue radioactivity. One week after antibody administration, tumor:liver ratios ranged from 6.9:1 to 100:1 and tumor:serum ratios from 4.1:1 to 25.2:1. 99mTc-albumin blood pool studies showed that liver metastases were hypovascular, emphasizing the selective localization of mAbA33 despite poor tumor-blood flow. Control mAbTA99 studies showed mAbA33 localization was antigen-specific; tumor:liver ratios were 2.3- to 45-fold higher for specific antibody. In metastatic lesions, radioisotope was localized primarily in the viable periphery; however, even the necrotic tumor core concentrated specific antibody. External imaging showed isotope visualization in some patients' large bowel; whether this represents specific antibody uptake or gastric iodine secretion is unclear.

Distribution of radiolabeled monoclonal antibody MX35 F(ab')2 in tissue samples by storage phosphor screen image analysis: evaluation of antibody localization to micrometastatic disease in epithelial ovarian cancer.

Our objective was to quantify the targeting of the monoclonal antibody (mAb) MX35 F(ab')2 to micrometastatic epithelial ovarian cancer. This mAb detects a Mr 95,000 glycoprotein with homogeneous distribution on 80% of ovarian tumor specimens. Six patients with minimal residual disease from an imaging trial were injected with 2 or 10 mg of 131I- and 125I-labeled mAb MX35 F(ab')2. Biopsied samples were removed at second-look laparotomy 1-5 days post-i.v. or -i.p. infusion of antibody. Serial cryostat sections were stained by indirect immunoperoxidase method for antigen distribution and exposed to storage phosphor screens for quantitative autoradiography. Coregistration of tumor histology, antigen expression, and radionuclide distribution demonstrated specific localization in micrometastatic tumor foci (50 micrometer to 1 mm) found within tissue stroma. The radiolabeled antibody uptake determined by well scintillation counts ranged between 5.2 and 223.5 x 10(-4) percentage of injected dose/g of tumor tissue for 131I. Specific localization of mAb in tumor was determined by tumor:normal tissue (fat) ratios ranging from 0.9:1 to 35.9:1 for 131I. The high resolution and linear response of the storage phosphor screen imager was used to estimate the radionuclide activity localized in each micrometastatic site. Quantitation of phosphor screen response revealed microCi/g values of 0.026-0.341 for normal tissue and 0.184-6.092 for tumor biopsies, evaluated 4 or 5 days post-antibody injection. The tumor:normal tissue (adjacent to tumor) ratios were between 1 and 4 times greater using the phosphor screen method than well counter measurements, but even larger variations of ratios up to 20:1 were observed between tumor cell foci and stromal cells within the same tissue section. This study has demonstrated that mAb MX35 F(ab')2 localizes to the micrometastatic ovarian carcinoma deposits within the peritoneal cavity. The dosimetry results suggest a therapeutic potential for this antibody in patients with minimal residual disease (<5 mm).

A case-case analysis of factors related to overexpression of p53 in endometrial cancer following breast cancer.

We studied 54 patients diagnosed with endometrial cancer between 1981 and 1994 following a diagnosis of breast cancer. We used a case-case analysis, comparing tumors with and without overexpression of the p53 gene product to evaluate the association of putative p53 mutations with tamoxifen use and other risk factors for endometrial cancer. Twenty-four % of the tumors showed strong positive staining for the p53 gene product. Tumors in a more advanced stage (stage 2, 3, or 4, compared to stage 1) were more likely to overexpress p53 [odds ratio (OR) = 4.2; 95% confidence interval (CI), 1.1-16.2], as were tumors with serous or clear cell, compared to endometrioid, histology (OR = 5.8; 95% CI, 1.3-26.5). There was a small association between p53 overexpression and treatment with tamoxifen for breast cancer (OR = 2.6; 95% CI, 0.69-9.8). There was a strong relationship between overexpression of p53 and having a first-degree relative with breast cancer (OR = 12.3; 95% CI, 2.6-57.4) and between overexpression of p53 and having an additional cancer, i.e., at sites other than breast or endometrium (OR = 7.9; 95% CI, 1.6-40.1). In this group of women, genetic predisposition to cancer, as reflected in family history of breast cancer and personal history of an additional primary cancer, was strongly associated with overexpression of p53 in endometrial tumors. The results suggest that use of tamoxifen may be associated with an increase in tumors that overexpress p53, although the results could be due to chance.

Diagnosis of tubular injury in renal transplant patients by a urinary assay for a proximal tubular antigen, the adenosine-deaminase-binding protein.

Two murine monoclonal antibodies (URO-4 and URO-4a)--which detect different epitopes of a proximal tubular cell glycoprotein antigen, the adenosine-deaminase-binding protein (ABP)--have been formatted into a sandwich enzyme immunoassay for detection of ABP in the urine. Serial urine samples from 34 renal transplant patients during the first six months posttransplant were analyzed to determine the correlation of this test with clinical rejection and cyclosporin (CsA) nephrotoxicity. In 29/29 acute rejection episodes the ABP level was elevated, beginning 1-7 days prior to treatment of rejection. Eighteen patients were treated for rejection with courses of OKT3 or antithymocyte globulin: 0/6 whose ABP level fell to normal during therapy had rerejection; 10/12 whose ABP level remained elevated had rerejection within 7 days of therapy completion. Of 15 patients treated with CsA, 7 had no rejection or drug toxicity; all 7 had normal ABP levels. The remaining 8 had CsA nephrotoxicity, all in association with elevated ABP levels that rapidly fell to normal with decreased CsA dose. An additional 7 patients with creatinine elevations more than 6 months posttransplant were studied: 5 had chronic vascular changes on biopsy, no response to increased immunosuppression, and normal ABP levels; 2 had a cellular infiltrate on biopsy, response to increased immunosuppression, and elevated ABP levels. We conclude that the urinary ABP assay provides information useful in the management of renal transplant patients with acute and chronic rejection and CsA toxicity.

Some monoclonal antibody reagents (C219 and JSB-1) to P-glycoprotein contain antibodies to blood group A carbohydrate determinants: a problem of quality control for immunohistochemical analysis.

Monoclonal antibodies (MAb) C219 and JSB-1 have been used extensively in the analysis of P-glycoprotein expression in normal and malignant tissues. This study demonstrates that some commercial lots of these MAb, even those supplied as purified immunoglobulins, contain contaminating anti-A blood group antibodies. In both sources of reagent, the antibody was specific for a particular A structure, known as repetitive or Type 3 A. These observations may account for earlier studies showing polymorphic variation in P-glycoprotein expression in epithelial tissues and an apparent correlation with the A blood type of the donor. Such reactivity can be eliminated by absorption of anti-P-glycoprotein reagents with A erythrocytes. These data re-emphasize the importance of evaluating MAb samples for unsuspected contaminating antibodies.

Immunohistochemical localization of P-glycoprotein in adult human ovary and female genital tract of patients with benign gynecological conditions.

The multidrug-resistance gene, MDR1, encodes a plasma membrane glycoprotein termed P-glycoprotein, which mediates active cellular efflux of certain cytotoxic agents. Two mouse monoclonal antibodies (MAb), C219 and JSB-1, were used to identify P-glycoprotein in frozen tissue from the female genital tract of 14 women with benign gynecological conditions; multiple samples from several sites in the genital tract were available from seven patients. P-glycoprotein was detected in the ovarian surface epithelium in four of 14 cases, in the Fallopian tube in three of five cases, in occasional epithelial cells of the endometrial glands in two of five cases, in some endocervical glandular epithelium in three of five cases, in ectocervical squamous epithelium in one of the two cases, and in luteinized cells of the eight cases in which a corpus luteum was present in the specimen. Positive staining with these two MAb was also observed in some endothelial cells in the cortex of the ovary and in the stromal tissue of the myometrium, endometrium, and endocervix. These studies suggest that, if epithelial ovarian cancers are derived from the surface epithelial cells of the ovary, a small proportion of the cancers might be expected to retain the phenotype found in non-cancerous cells and to express P-glycoprotein.

Immunoanatomic dissection of the human urinary tract by monoclonal antibodies.

The immunoanatomy of the human kidney and urinary tract has been analyzed by a panel of mouse anti-human monoclonal antibodies that define specific domains and structures. The differentiation antigens detected by these monoclonal antibodies represent a series of glycoproteins characteristic of different cell types. They differ from the blood group antigens and appear to be distinct from other antigens previously described within the kidney or urinary tract. The antigens recognized by these monoclonal antibodies represent an immunohistologic dissection of the human nephron. These antibodies have a broad range of potential applications in studying embryogenesis and pathogenesis of nonneoplastic and neoplastic diseases of the human kidney and urothelium.

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.

Reversal of the low-affinity neurotrophin receptor stromal-epithelial expression pattern between benign and malignant human prostate.

Reduced expression of the low-affinity p75 neurotrophin receptor (p75(NTR)) occurs in prostate epithelial cells during malignant transformation. Recent studies indicating that the p75(NTR) can transduce signals that induce apoptosis suggest that diminished p75(NTR) in transformed prostate cells may contribute to immortalization. Mutations in the transmembrane domain of the p75(NTR) gene have been associated with decreased p75(NTR) protein expression and may block the ability of the p75(NTR) to induce apoptosis. Therefore, we used Western blot to analyze prostate cancer (PC) cell lines for p75(NTR) protein expression and gene single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing to analyze mutations in the transmembrane domain of the p75(NTR). p75(NTR) Protein was present in all cell lines, and mutations in the p75(NTR) gene were not detected in cDNA derived from any cell line. To define the expression pattern of p75(NTR) in PCs in vivo, we used immunohistochemical techniques to examine tissue specimens from 20 benign, 19 malignant primary, and 14 metastatic prostate specimens. In benign prostate tissues, expression of p75(NTR) was universally detected in basal cells but not in secretory epithelial or stromal cells. In both primary and metastatic PC tissues, p75(NTR) immunoreactivity could not be detected in malignant prostate epithelial cells. However, in contrast to the benign prostate, p75(NTR) protein was expressed in stromal cells surrounding malignant epithelial cells. Stromal p75(NTR) expression was present in 84% (16 of 19) primary and in 86% (12 of 14) metastatic specimens. These data show that in the benign prostate p75(NTR) protein is expressed by basal cells and not stromal cells whereas in malignant prostate p75(NTR) protein is expressed by stromal cells but not prostatic carcinoma cells. Reversal of the p75(NTR) stromal-epithelial pattern of expression between benign and malignant prostate suggests that p75(NTR) may contribute to the development and maintenance of prostate cancer.

Altered regulation of cell surface peptidases in human cholesteatoma.

Cholesteatoma is a destructive process involving an accumulation of desquamated keratin arising from squamous epithelium that pathologically has invaded the middle ear or mastoid process. The clinical hallmarks of cholesteatomas, namely invasion of healthy tissues, migration, unrestrained proliferation, aggressiveness, recidivism, and uncoordinated differentiation predict the existence of defects in the normal biology and biochemistry of the cellular constituents that compose a cholesteatoma, as well as in the cellular interactions between these cells, the surrounding normal tissue, and the host. In the current report, we analyzed 11 cholesteatomas and matched healthy tissue for altered expression in four different cell surface peptidases, aminopeptidase A, aminopeptidase N, dipeptidyl peptidase IV, and neutral endopeptidase. We suggest that peptidases may modulate cell growth and differentiation by inactivating stimulatory signals (or conversely, by activating inhibitory signals).

Immunoanatomic distribution of cytostructural and tissue-associated antigens in the human urinary tract.

The main objective of the present study is to define the expression and/or modulation of antigenic phenotypes in cells of the normal human kidney and urothelium according to cell type. Fourteen antibodies detecting differentiation and structural antigens expressed in the human urinary tract have been used to define the immunoanatomic distribution of these antigenic systems. They include urinary tract antigens (Tamm-Horsfall glycoprotein and prostate-specific antigen), tissue-associated antigens (epithelial membrane antigen, Factor VIII antigen, and Protein S-100), and cytoskeletal antigens of the intermediate filament classes (cytokeratins, vimentin, desmin, glial fibrillary acidic protein, and neurofilaments. Immunofluorescence and immunoperoxidase analyses performed on normal human fetal and adult tissue sections have demonstrated that these antigens are expressed by different cell types and domains of the nephron. Studies correlating normal fetal and adult tissues reveal that some of the antigens appear at distinct stages of maturation, representing early and late antigenic expression events. These antibodies offer a wide range of potential applications that include studies of embryogenesis of the human urinary tract and immunopathologic analyses of neoplastic and nonneoplastic diseases of the human kidney and urothelium.

Comparison of MUC-1 mucin expression in epithelial and non-epithelial cancer cell lines and demonstration of a new short variant form (MUC-1/Z).

Mucins, including MUC-1, are generally considered to be products of epithelial tissues and of their tumors. To examine the possible expression of MUC-1 in other cell types, a panel of human epithelial and non-epithelial tumor cell lines was studied by reverse transcriptase polymerase chain reaction (RT-PCR), Northern blot analysis, immunocytology and radioimmunoprecipitation. Using the highly sensitive RT-PCR method, products corresponding to the non-repetitive 5' and 3' MUC-1 sequences were detected in all the cell lines examined. Amplified products lacking the tandem repeat region of MUC-1, including a new short form (designated MUC-1/Z) different from the previously reported MUC-1/Y protein, were also detected in most cell lines tested. Northern blot analysis, using a probe to the variable number tandem repeat (VNTR) region, confirmed the presence of MUC-1 mRNA in the astrocytoma, melanoma and neuroblastoma cell lines studied. MUC-1 protein was detected by immunocytology in these cell lines using monoclonal antibody (MAb) 139H2. Immunoprecipitation analysis with [3H]-glucosamine-labeled cell lysates and MAb 139H2 or an antibody to the cytoplasmic domain, CT-1, detected MUC-1 protein in 2 epithelial cell lines, an astrocytoma cell line (SK-MG-4) but not in the melanoma and neuroblastoma cell lines studied. Northern blot analysis using a probe to the 3' end of MUC-1 mRNA, confirmed the presence of MUC-1 mucin and also identified short products corresponding to the size of the short variant forms. Protein products corresponding to the MUC-1/Y and MUC-1/Z variant forms were not observed using either [3H]-glucosamine-labeled OVCAR-3 cells or [3H]-amino acid-labeled MCF-7 cells and either CT-1 antibody or MAb 232A1, detecting an epitope to the C-terminal region. Thus, depending on the sensitivity of the assay used, varying amounts of MUC-1 mRNA and protein could be detected in non-epithelial tumor cell lines. Although the amounts of MUC-1 in these cell lines are much lower than in carcinomas, it is possible that MUC-1 mucin serves a similar function in non-epithelial as in epithelial cells. The possible role of MUC-1/Y and MUC-1/Z variant forms in these cell lines is not understood.

The antigen identified by a mouse monoclonal antibody raised against human renal cancer cells is the adenosine deaminase binding protein.

The antigen recognized by a mouse monoclonal antibody (mAb S27) raised against a human renal cancer cell line has been identified as the adenosine deaminase binding protein. mAb S27 immunoprecipitates binding protein purified from a soluble fraction of human kidney. It also recognizes the mature 120,000-dalton membrane form of binding protein from [35S]methionine-labeled human fibroblasts, HepG2 cells, and the renal cancer cell line against which the antibody was raised. A rabbit polyclonal antibody raised against purified kidney binding protein completely precipitates mAb S27-reactive material from labeled membrane extracts. mAb S27 does not precipitate the initially synthesized 110,000 molecular weight precursor of binding protein in fibroblasts and recognizes only a small portion of binding protein precursor in labeled HepG2 cells suggesting that the antigenic determinant recognized by mAb S27 may be a post-translational modification present on the mature form of binding protein or that mAb S27 recognizes molecules in a certain conformation. Glycopeptides derived from purified soluble kidney binding protein or exogenously added adenosine deaminase do not inhibit the immunoprecipitation of binding protein by mAb S27, indicating that the mature oligosaccharide chains of binding protein are not the determinant recognized by mAb S27 and that bound adenosine deaminase does not mask the antigenic sites on binding protein. The fact that monoclonal antibody S27, previously shown (Ueda, R., Ogata, S., Morissey, D. M., Finstad, C. L., Szkudlavek, J., Whitmore, W. F., Oettgen, H. F., Lloyd, K. O., and Old, L. J. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 5122-5126) to detect a cell surface antigen on cultured renal cancer cells, is directed against the adenosine deaminase binding protein confirms and extends the earlier observation (Andy, R.J., and Kornfeld, R. (1982) J. Biol. Chem. 257, 7922-7925) that binding protein is located on the cell surface.

Selection of carbohydrate antigens in human epithelial ovarian cancers as targets for immunotherapy: serous and mucinous tumors exhibit distinctive patterns of expression.

Expression of blood group-related carbohydrate antigens was examined in frozen sections from a series of ovarian carcinomas of different histological types using an indirect immunoperoxidase technique. Antigenic specificities belonging to the O(H) and Lewis blood group families (H-1, H-2, Le(a), sLe(a), Le(x), sLe(x), Le(b) and Le(y)) or the mucin-core family (Tn, sTn and TF) were studied. A distinct difference in antigen expression between mucinous and other ovarian carcinomas (serous and endometrioid) was observed. Specifically, mucinous tumors tended to express sTn, Le(a) and sLe(a) strongly and homogeneously, whereas serous and endometrioid tumors rarely expressed these specificities and, in contrast, expressed Le(y) and H type 2 antigen strongly. When expressed in serous tumors, sTn was usually distributed in a heterogeneous pattern, whereas sTn expression in mucinous tumors was much more homogeneous. The distribution of Le(y) in serous tumors was noticeably homogeneous. H-1, Le(x), sLe(x), Le(b), TF and Tn specificities were rarely expressed in any type of ovarian carcinoma. Our results provide further support for the different histogenesis of mucinous and non-mucinous tumors and indicate alternative differentiation pathways for the 3 pathological subtypes of ovarian tumor. They also provide the basis for the choice of carbohydrate antigens for active and passive immunotherapy of ovarian carcinomas.