Monoclonal antibodies against human urinary bladder carcinomas: selectivity and utilization for gamma scintigraphy

A monoclonal antibody (BL2-10D1) reacting with a bladder-cancer-associated antigen

A hybridoma cell line secreting an IgM monoclonal antibody (MAb) was produced after immunizing a mouse with RT4 cells and a crude suspension of human bladder carcinoma cells (WHO grades II and III TCC). This MAb reacted with RT4 target cells derived from a human transitional bladder cancer but failed to react with a majority of non-bladder cancer cell lines. Immunohistological studies indicate that this MAb reacts inconstantly with normal bladder: in positive cases only a few superficial cells (5% to 10% umbrella cells) are stained but not intermediate or basal cells of the urothelium. This MAb was evaluated on 118 tumors: it reacted with tumor tissue in a majority of grade I (79.5%) and grade II papillary TCC (77.3%), less with grade III papillary TCC (45%) and very rarely with invasive non-papillary TCC (14%). In cases of flat lesions a strong reactivity of superficial, intermediate and/or basal layer cells was observed in 50% of moderate and severe dysplasia and in all cell layers of carcinomas in situ (CIS)(9/9).

Diagnostic and therapeutic utility of monoclonal antibodies in urologic oncology

Remarkable advances in the treatment of urologic malignancies have recently been made. Monoclonal antibodies selective for a variety of normal and malignant urologic tissues have been useful in defining normal antigens and tumor-associated antigens and have potential as diagnostic and immunotherapeutic agents. In renal cancer, monoclonal antibodies can define serum markers, radiolabel tumor xenografts, and assist in specific tissue diagnosis. Additionally, there is potential for these antibodies either alone or as conjugates to localize and kill tumors. Monoclonal antibodies to bladder cancer associated antigens are able to demonstrate differential antigen expression on superficial versus invasive tumors, to refine urinary cytologic diagnosis of bladder cancer, and to predict invasive recurrence of superficial cancer. Monoclonal antibodies have localized bladder tumor xenografts and can inhibit tumor growth when conjugated to radioisotopes or toxins. In prostate cancer monoclonal antibodies to prostate antigens are not usually tumor specific. Monoclonal antibodies to prostate antigen (PA) and prostatic acid phosphatase (PAP) are able to localize prostate cancer metastases. Chemotherapy-conjugated anti-PAP monoclonal antibodies have demonstrable inhibition on human prostate cancer xenografted tumor growth. Monoclonal antibodies have defined normal and tumor-associated antigens in urologic cancers and are expected to be useful in immunodiagnosis and cancer therapy in the near future.

Bladder cancer cell line cross-contamination: identification using a locus-specific minisatellite probe

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Radioimmunodetection of cancer with monoclonal antibodies: current status, problems, and future directions

Early studies of immunoscintography with affinity-purified 131I-labeled polyclonal antibodies reactive against oncofetal antigens such as carcinoembryonic antigen (CEA) were moderately successful in detecting metastatic colorectal carcinoma. However, because of low tumor to background ratios of isotope, background subtraction techniques using 99Tc-labeled albumin were required to visualize small lesions. Antisera were often of low titer and lacked specificity. These problems could be overcome for the most part following the development of highly specific monoclonal antibodies (MoAb) against a variety of tumor-associated antigens. A number of clinical trials using 131I- or 111In-labeled MoAb to image tumors have demonstrated successful localization without the use of subtraction techniques. Variables limiting the usefulness of murine MoAb for diagnosis have included increased localization in liver and spleen, tumor vascularity and heterogeneity of antigen expression, and development of human antimurine globulins. Methods to overcome some of these problems are discussed. Radiolabeled MoAb appear useful as an adjunct to conventional diagnostic techniques both as a means to predict which antibodies might be useful for treatment and, in select patients, as a basis for treatment decisions.

Effect of the antiprogesterone RU-38486 on meningioma implanted into nude mice

Meningiomas have been shown to have steroid-binding proteins. In vitro, estradiol, progesterone, and the antiestrogen tamoxifen stimulate tumor growth. However, incubation of tumor cells with an antiprogesterone agent results in tumor inhibition. In this investigation, a human meningioma was implanted subcutaneously in athymic nude mice. Two treatment groups were established, one receiving the antiprogesterone agent RU-38486 (10 mg/kg/day in suspension) and the other receiving only vehicle. After 3 months, the tumor growth index (defined as the tumor volume at 3 months divided by the initial tumor volume) was 0.25 +/- 0.46 (mean +/- standard deviation) in the group receiving antiprogesterone and was 1.54 +/- 0.58 in the control group (p = 0.041). Further investigation of the effect of antiprogestational agents on the growth and hormone-binding proteins of other meningiomas will better define the mechanism of their effects.

Isolation and characterization of two bladder carcinoma-associated antigens

By the use of mouse monoclonal antibodies we have earlier defined five distinct antigens associated with transitional cell carcinoma of the human urinary bladder (TCC). Two of these antigens have now been purified and partially characterized. For their purification from isolated tumor cell membranes, a rapid and efficient method of affinity chromatography was developed in which the coupling of monoclonal antibodies to protein A-Sepharose was fortified by treatment with glutaraldehyde. From these columns, 60-80% of the antigenic activity present in membrane lysates could be recovered by acid elution, corresponding to approximately 0.25-0.5 micrograms antigen protein per mg membrane protein added. The two isolated antigens are relatively hydrophobic membrane components not found in normal bladder tissue. The antigen defined by the monoclonal antibody S2C6 is confined to bladder carcinoma and B cells. It is a glycosylated, ConA-binding polypeptide with Mr 50 000 as established by SDS-PAGE. It is acidic with an IP of 3.2, heat stable up to 85 degrees C, stable at low pH (2.0) but sensitive to SDS. The antigen defined by the monoclonal antibody 7E9 is confined to bladder carcinoma but is also weakly expressed in some blood vessel endothelium. It consists of two main polypeptides of Mr 29,000 and 23,000 which do not bind to ConA. It has an IP of 7.4 and its antigenic activity is abolished by heating to 50 degrees C for 5 min. As the S2C6 antigen, it is stable at low pH but susceptible to SDS.

Altered glycosylation of membrane glycoproteins in human uroepithelial cell lines

Total cellular glycopeptides of 7 human uroepithelial cell lines that differ in the grade of transformation (TGr) were analysed by gel filtration and affinity chromatography on immobilized lectins. The 4 cell lines that are tumorigenic in nude mice and invasive in vitro (TGr III) possess more highly branched, tri- and tetraantennary N-acetyllactosaminic glycans, with less biantennary glycans than the 2 non-tumorigenic, noninvasive (TGr II) cell lines examined. The only exception to this general pattern is the third cell line, which is classified as TGr II. The cellular glycopeptide distribution pattern in this cell line is similar to that of the TGr III cells. The possible relationship between altered glycosylation of membrane glycoproteins and the expression of a malignant phenotype is discussed.

Fourier analysis of the cell shape of paired human urothelial cell lines of the same origin but of different grades of transformation

The rationale of the present investigation is the observations made by many authors of changes in the molecular structure of the cell surface during the multistep process of malignant transformation. These changes may influence cell-matrix and cell-cell interactions and thereby cause changes in cell adhesiveness and cell shape. The aim of the present work was to investigate whether the development of various grades of transformation in vivo and in vitro of human urothelial cells is accompanied by significant changes in cell shape as measured by Fourier analysis. The following transformation grades (TGr) have been defined (Christensen et al. 1984; Kieler 1984): TGr I = nonmalignant, mortal cell lines that grow independently of fibroblasts and have a prolonged life span. TGr II = nonmalignant cell lines with an infinite life span. TGr III = malignant and immortal cell lines that grow invasively in co-cultures with embryonic chick heart fragments and possess tumorigenic properties after s.c. injection into nude mice. Comparisons of 4 pairs of cell lines were performed; each pair was of the same origin. Two pairs--each including a TGr I cell line (Hu 961b and Hu 1703S) compared to a TGr III cell line (Hu 961a or Hu 1703He)--were derived from two transitional cell carcinomas (TCC) containing a heterogeneous cell population. Two additional cell lines classified as TGr II (HCV-29 and Hu 609) were compared to two TGr III sublines (HCV-29T and Hu 609T, respectively) which arose by "spontaneous" transformation during propagation in vitro of the respective maternal TGr II-cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)