Search

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.

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.

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.

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.