Diploid fibroblast (dFb) cultures were established from a total of 106 skin and serosa biopsies of human adults. Using an optimized enzymatic dissociation procedure, 10(11) dFb/cm2 skin were obtained from patients younger than 60 years after an average time of 89 +/- 8 days, with a mean population doubling time of 3.87 +/- 1.4 days. Enzymatic dissociation of skin biopsies yielded cultures of significantly higher growth capacity of dFb than those prepared by mechanical dissociation followed by spontaneous outgrowth of cells. The plating efficiency that may be crucial for clonal selection of transfected cells was negligible when dFb were plated without feeder cells at low density, while it was enhanced to 9-24% by the addition of a feeder layer of irradiated human embryonal fibroblasts. DFb secreted various cytokines with spontaneous release of interleukin-6 (IL-6) in high quantities of up to 20 ng/10(6) cells/24 hr. In addition, one-third of the culture secreted substantial amounts of granulocyte-macrophage colony-stimulating factor (GM-CSF), while low amounts of tumor necrosis factor-alpha (TNF-alpha) were detectable in some cases after irradiation of the cells. Comparison of various transfection methods by a transient luciferase expression assay demonstrated that receptor-mediated gene transfer was approximately 10-fold more efficient than cationic lipofection of dFb, while electroporation resulted in substantially less expression of the reporter gene. We conclude that primary dFb can be obtained reproducibly from human adults and represent a suitable target cell population for receptor-mediated gene transfer and cationic lipofection.(ABSTRACT TRUNCATED AT 250 WORDS)

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Vaccination with gene-transfected tumor cells has recently been proposed as a new strategy in the immunotherapy of cancer. Since autologous tumor cells provide an optimal antigen profile, the possibility of generating single cell suspensions from renal cell carcinoma (RCC), malignant melanoma (MM), colon carcinoma (CC), and non-small-cell lung cancer (NSCLC) biopsies was investigated. One hundred and seventy-four tumor biopsies were processed by mechanic and enzymatic dissociation, yielding 1-2 × 10⁶ cells/g tumor (median), irrespective of tumor type. Primary tumor cell cultures (PTCC) of > 10⁷ cells were established from 29 of 86 (34%) RCC, 14 of 38 (37%) MM, 11 of 23 (48%) NSCLC and 4 of 27 (15%) CC specimens. The amount of non-tumor cells, as assessed by morphology and immunocytology, was generally low ( < 30%) in RCC (35 of 41) and MM (11 of 17), while it exceeded 60% in 8 of 11 PTCC from NSCLC and 3 of 11 CC. A high tumor cell yield was obtained in biopsies with a high degree of vascularization and in the virtual absence of necrosis. Thus, PTCC > 10⁷ cells were obtained in 73% of MM with a high degree of vascularization and in 22% of MM with a low degree of vascularization (p < 0.007). Long-term tumor cell cultures exceeding 20 passages were established in 24 of 86 (18%) RCC, 7 of 38 (18%) MM and 3 of 27 (11%) CC, while successful implantation in nude mice was achieved in 8 of 20 RCC and 5 of 10 MM. Thus, under the conditions described, >10⁷ primary tumor cells of high purity could be generated from about one third of RCC and MM biopsies, while the success rate increased to > 50 and > 70%, respectively, in samples with a high degree of vascularization generated by an optimized biopsy technique excluding necrotic parts.

We compared the cytogenetic pattern of 20 different primary tumor cell cultures (PTCC) of renal cell carcinoma (RCC) to their cytokine secretion and oncogene expression. High secretion of IL-6 (gene locus on chromosome 7p21-pl4) was correlated with the gain of an additional chromosome 7. Structural changes involving chromosome 5q22, the site of the GM-CSF gene, were matched with the high secretion of GM-CSF in PTCC. No such association was found for pymicroglobulin, TGF-(3i, TNF-a, IL-8, and oncogenes, such as c-fos, c-myc, and pan-ras. Our approach may be useful in simultaneously analyzing several factors contributing to tumor progression and may contribute to understanding the multistep development of RCC.