Development and characterization of an interleukin-2-transduced human ovarian carcinoma tumor vaccine not expressing major histocompatibility complex molecules.

OBJECTIVE: We initiated studies to develop cytokine-secreting human ovarian carcinoma cells for the purpose of using these cells as vaccines for the treatment of advanced epithelial ovarian cancer. STUDY DESIGN: A human ovarian carcinoma cell line (UCI-107) was genetically engineered to secrete the cytokine interleukin-2 by retroviral-mediated gene transduction. RESULTS: One clone, termed UCI-107A IL-2 AS, constitutively secreted high levels of interleukin-2 (i.e., 2000 to 2300 pg/ml/10(5) cells per 48 hours) for > 55 passages and 8 months of study. Unlike parental- and vector-transduced cells, UCI-107A IL-2 AS cells were aneuploid and failed to express major histocompatibility complex class I and HER2/neu surface antigens. UCI-107A IL-2 AS cells were highly resistant to killing by gamma irradiation and continued to produce high levels of interleukin-2 even after irradiation with 10,000 cGy. Balb/C nude mice injected intraperitoneally with UCI 107-A IL-2 AS cells survived significantly longer than control animals, with 25% of the animals totally rejecting their tumors. UCI-107A IL-2 AS was totally resistant to killing by fresh allogeneic peripheral blood lymphocytes in four hour chromium 51 release assays but induced high levels of killing in 72-hour long-term cytotoxic assays. CONCLUSION: The potential use of these interleukin-2-secreting ovarian carcinoma cells as vaccines for women with advance ovarian cancer will be discussed.

Development and in vitro characterization of a GM-CSF secreting human ovarian carcinoma tumor vaccine.

A human ovarian carcinoma cell line (UCI-107) was genetically engineered to secrete the cytokine granulocyte-macrophage colony stimulating factor (GM-CSF), by retroviral medicated gene transduction. This line was transduced with the LXSN retroviral vector containing the human GM-CSF gene and the neomycin resistance selection marker. Numerous GM-CSF secreting clones were randomly isolated and one clone, termed UCI-107M GM-CSF-MPS, extensively characterized. This clone was shown to constitutively secrete high levels of GM-CSF (ie 420-585 pg ml-1 105 cells-1 48 h-1 for over 35 passages and 6 months of study. Like the parental cell line UCI-107, UCI-107M GM-CSF-MPS cells expressed MHC class I and Her2/Neu surface antigens but did not express detectable MHC class II, ICAM-1 or CA-125. No change in the expression of these surface proteins was noted between the parental cells and this GM-CSF secreting clone. The morphology of UCI-107M GM-CSF-MPS did not differ from that of the parental or LXSN vector control cells; however, parental cells had a slightly faster growth rate than the transductants. UCI-107M GM-CSF-MPS was sensitive to gamma irradiation, since as little as 2500 rads killed the cells within 10 days of irradiation. However, even after higher doses of irradiation (ie 10000 rads), GM-CSF secretion continued in vitro until about day 8. Interestingly, irradiation induced up-regulation of the surface antigens previously expressed, and they remained up-regulated for as long as the cells remained viable. The potential use of these GM-CSF secreting ovarian carcinoma cells as vaccines for women with advanced ovarian cancer will be discussed.

Development and characterization of an IL-4-secreting human ovarian carcinoma cell line.

Human ovarian carcinoma cell lines were genetically engineered to secrete the cytokine interleukin-4 (IL-4) by retroviral-mediated gene transduction. These cells were transduced with the LXSN retroviral vector containing the human IL-4 gene and the neomycin resistance selection marker. Numerous IL-4-secreting clones were isolated from different papillary serous carcinoma cell lines, including SKOV-3, UCI-101, and UCI-107, and one clone derived from UCI-107 extensively characterized. This clone, termed UCI 107E IL-4 GS, was shown to constitutively express high levels of IL-4 (i.e., 900 to 1300 pg/ml/10(5) cells/48 hr) for over 35 passages and 6 months of study. Like the parental cell line (UCI-107), UCI 107E IL-4 GS cells expressed MHC class I and Her-2/neu surface antigens but did not express detectable MHC class II, ICAM 1, CA 125, or IL-4 receptors. No increase in expression of surface proteins was noted between parental and UCI 107E IL-4 GS. The morphology of this clone did not differ from that of the parental or LXSN vector control cells; however, parental cells had a faster growth rates than transductants. UCI 107E IL-4 GS was sensitive to gamma irradiation since as little as 2500 rad killed most of the cells within 10 days of irradiation. However, after irradiation, IL-4 secretion continued until about Day 8. The potential use of these IL-4-secreting ovarian carcinoma cells as vaccines for woman with advanced ovarian cancer will be discussed.

Spontaneous release of interleukin-6 by primary cultures of lymphoid and tumor cell populations purified from human ovarian carcinoma.

Interleukin-6 (IL-6) is a cytokine that has been implicated as a growth factor in human ovarian carcinoma, yet the in vivo source of IL-6 in patients remains undefined. We measured IL-6 by ELISA in cell-free ascites (CFA) of 19 patients with ovarian carcinoma. IL-6 was detectable in all samples (mean level 3.3 ng/ml). To identify the cellular source of IL-6, we measured this cytokine by ELISA in 24-48 h supernatants of cultured lymphocyte-, macrophage-, and tumor cell-enriched populations purified from three solid ovarian carcinomas by centrifugal elutriation. All cell populations spontaneously released IL-6; however, tumor cells and tumor-associated macrophage released levels of IL-6 that greatly exceeded those released by tumor-associated lymphocytes. Kinetic studies revealed that IL-6 was detectable at 6 h and that levels increased in all cultures examined over a 48 h time course. These data suggest that both tumor and infiltrating host cells may be the source of the high levels of IL-6 found in carcinomatous ascites. Furthermore, although all three cell types examined may contribute to IL-6 production in patients with ovarian carcinoma, tumor cells are perhaps the most clinically significant source.

Host-tumor interaction in ovarian cancer. Spontaneous release of tumor necrosis factor and interleukin-1 inhibitors by purified cell populations from human ovarian carcinoma in vitro.

The biological activity of tumor necrosis factor (TNF alpha/beta) and interleukin-1 beta (IL-1 beta) can be blocked by soluble, naturally occurring molecules--TNF alpha/beta binding proteins (BP-55 and BP-75), derived from the extracellular portion of the 55- and 75-kDa TNF alpha/beta membrane receptors, and IL-1 receptor antagonist (IL-1ra), respectively. We examined the levels of these cytokines and their inhibitors in cell-free ascites of 18 patients with advanced ovarian carcinoma by ELISA. Levels of both TNF BP and IL-1ra dramatically exceeded those of TNF and IL-1; thus, it is unlikely that these cytokines are active in ascites from patients with this disease. We then elutriated solid tumor samples from three additional patients, yielding pure populations of tumor cells, macrophages, and lymphocytes. Cells were cultured for up to 48 hr and the spontaneous production of TNF, IL-1, and their inhibitors was measured by ELISA. Tumor cells and macrophages both released inhibitors for TNF and IL-1. Tumor cells released IL-1ra and BP-55, while macrophages released IL-1ra and BP-75. Kinetic studies showed that both tumor cells and macrophages produced an initial burst of TNF alpha and IL-1 beta which was overtaken within 48 hr by a sustained production of TNF BP and IL-1ra. Lymphocytes released no TNF alpha or TNF beta, which alone suggests that tumor associated lymphocytes are locally quiescent in vivo. TNF and IL-1 inhibitors originate from tumor cells and tumor associated macrophages and probably block TNF and IL-1 activity locally and regionally in ovarian carcinoma patients. Whether this phenomenon contributes to the pathogenesis of this disease remains to be determined.