Induction of G250-targeted and T-cell-mediated antitumor activity against renal cell carcinoma using a chimeric fusion protein consisting of G250 and granulocyte/monocyte-colony stimulating factor

Immunotherapy targeting for the induction of a T-cell-mediated antitumor response in patients with renal cell carcinoma (RCC) appears to hold significant promise. Here we describe a novel RCC vaccine strategy that allows for the concomitant delivery of dual immune activators: G250, a widely expressed RCC associated antigen; and granulocyte/macrophage-colony stimulating factor (GM-CSF), an immunomodulatory factor for antigen-presenting cells. The G250-GM-CSF fusion gene was constructed and expressed in Sf9 cells using a baculovirus expression vector system. The Mr 66,000 fusion protein (FP) was subsequently purified through a 6xHis-Ni2+-NTA affinity column and SP Sepharose/fast protein liquid chromatography. The purified FP retains GM-CSF bioactivity, which is comparable, on a molar basis, to that of recombinant GM-CSF when tested in a GM-CSF-dependent cell line. When combined with interleukin 4 (IL-4; 1000 units/ml), FP (0.34 microg/ml) induces differentiation of monocytes (CD14+) into dendritic cells (DCs) expressing surface markers characteristic for antigen-presenting cells. Up-regulation of mature DCs (CD83+CD19-; 17% versus 6%) with enhanced expression of HLA class I and class II antigens was detected in FP-cultured DCs as compared with DCs cultured with recombinant GM-CSF. Treatment of peripheral blood mononuclear cells (PBMCs) with FP alone (2.7 microg/10(7) cells) augments both T-cell helper 1 (Th1) and Th2 cytokine mRNA expression (IL-2, IL-4, GM-CSF, IFN-gamma, and tumor necrosis factor-alpha). Comparison of various immune manipulation strategies in parallel, bulk PBMCs treated with FP (0.34 microg/ml) plus IL-4 (1000 units/ml) for 1 week and restimulated weekly with FP plus IL-2 (20 IU/ml) induced maximal growth expansion of active T cells expressing the T-cell receptor and specific anti-RCC cytotoxicity, which could be blocked by the addition of anti-HLA class I, anti-CD3, or anti-CD8 antibodies. In one tested patient, an augmented cytotoxicity against lymph node-derived RCC target was determined as compared with that against primary tumor targets, which corresponded to an 8-fold higher G250 mRNA expression in lymph node tumor as compared with primary tumor. The replacement of FP with recombinant GM-CSF as an immunostimulant completely abrogated the selection of RCC-specific killer cells in peripheral blood mononuclear cell cultures. All FP-modulated peripheral blood mononuclear cell cultures with antitumor activity showed an up-regulated CD3+CD4+ cell population. These results suggest that GM-CSF-G250 FP is a potent immunostimulant with the capacity for activating immunomodulatory DCs and inducing a T-helper cell-supported, G250-targeted, and CD8+-mediated antitumor response. These findings may have important implications for the use of GM-CSF-G250 FP as a tumor vaccine for the treatment of patients with advanced kidney cancer.

Interleukin 2 gene therapy for prostate cancer: phase I clinical trial and basic biology

Twenty-four patients with locally advanced prostate cancer (CaP) were enrolled in a phase I clinical trial using gene-based immunotherapy. A functional DNA-lipid complex encoding the interleukin 2 (IL-2) gene (Leuvectin; Vical, San Diego, CA) was administered intraprostatically into the hypoecogenic tumor lesion, using transrectal ultrasound guidance. Two groups of patients having locally advanced tumors were enrolled to receive a treatment regimen composed of two serial intraprostatic injections of the IL-2 gene agent administered 1 week apart. The first groups of patients included radical prostatectomy candidates who subsequently underwent surgery after the completion of the treatment regimen. The second group consisted of patients who had failed a prior therapy. Prostate specimens of the treated areas were attained after treatment and compared with the transrectal biopsies performed at baseline to assess for any responses. IL-2 gene therapy was well tolerated, with no grade 3 or 4 toxic reactions occurring. The most commonly reported symptoms were mild hematuria, transient rectal bleeding, and perineal discomfort that are likely attributable to the injection itself. During the entire course of treatment, there were no significant changes in American Urologic Association (AUA) symptom scores, in hematologic disturbances, electrolyte imbalances, or hepatic functions. Evidence of systemic immune activation was observed after IL-2 gene therapy, based on an increase in the intensity of T cell infiltration seen on immunohistochemical analysis of tissue samples from the injected tumor sites, and based on increased proliferation rates of peripheral blood lymphocytes that were cocultured with patient serum collected after treatment. Furthermore, transient decreases in serum prostate-specific antigen (PSA) (responders) were seen in 16 of 24 patients (67%) on day 1. Fourteen of the patients persisted in this decrease to day 8 (58%). In eight patients the PSA level rose (nonresponders). More patients (9 to 10) in the group that failed prior therapy responded to the IL-2 gene injections (chi-square test, p = 0.04), and 6 of the 9 also had lower than baseline PSA levels at week 10 after treatment. To the best of our knowledge, this is the first clinical study of its kind aimed at exploring the role of IL-2-based gene therapy in CaP patients. This phase I trial demonstrated the safety of intraprostatic Leuvectin injection, with transient PSA-based responses seen after therapy.

CL1-GFP: an androgen independent metastatic tumor model for prostate cancer

PURPOSE

The mechanisms responsible for tumor progression to androgen independence in prostate cancer (CaP) remain unknown. To characterize these changes and provide a basis for rational therapeutic strategies for advanced CaP, an in vivo model from a highly aggressive androgen independent CaP cell line with distinct cellular and molecular properties was developed.

MATERIALS AND METHODS

An aggressive androgen-independent cell line designated CL1 was derived from a slow-growing, and androgen-dependent, parental LNCaP cell line through in-vitro androgen-deprivation and selection. CL1 was stably transfected with a green fluorescence protein gene (CL1-GFP) and orthotopically injected into SCID mice. The pathologic behavior, histology, and molecular determinants of CL1 tumor and metastases were determined and characterized by standard light and fluorescent microscopy, and quantitative RT-PCR analysis.

RESULTS

CL1 is an anaplastic prostate cancer cell line which demonstrates extensive local invasion and metastases to various organs that can be visualized via GFP expression. When compared with parental LNCaP cells, RT-PCR analysis of the tumor revealed an over-expression of EGFR, b-FGF, VEGF, TGF-beta, IL-8, IL-6, and bcl-2 and a down regulated expression of the p53, E-cadherin and PTEN. In contrast to LNCaP cells, CL1 tumors express lower levels of androgen receptor and barely detectable PSA mRNA.

CONCLUSIONS

CL1-GFP represents an aggressive androgen-independent CaP tumor model derived through androgen deprivation whose pathologic development and molecular properties in animals resembles the clinical characteristics of hormone refractory prostate cancer (HRPC). Metastatic sites of CL1-GFP can be visualized with fluorescence microscopy offering a unique therapeutic model for the evaluation of drug sensitivity and other therapeutic modalities.

Androgen deprivation induces selective outgrowth of aggressive hormone-refractory prostate cancer clones expressing distinct cellular and molecular properties not present in parental androgen-dependent cancer cells

PURPOSE

The mechanism of progression of human prostate cancer (CaP) cells under androgen ablation therapy remains unclear. To study the alternative pathways of CaP cell growth under conditions of androgen deprivation, androgen-independent CaP variants were selected and expanded from an androgen-dependent CaP line via an in vitro androgen deprivation treatment. Cellular and molecular properties of these androgen-independent variants were characterized both in vitro and in vivo and compared with those of their parental androgen-dependent cells.

METHODS

Androgen deprivation treatment of an androgen-dependent CaP cell line, LNCaP, was carried out by replacing culture medium with RPMI 1640 medium plus 10% charcoal-stripped serum. Cells that survived through the androgen deprivation treatment were harvested and expanded in the androgen-deficient culture medium and were designated CL-1. The CL-1 cells were also recultured in androgen-containing medium and designated CL-2. The growth (cell cycle analysis, 3H-thymidine incorporation assay, growth expansion, and colonization efficiency), expression of CaP-associated markers (semiquantitative reverse transcriptase polymerase chain reaction), interaction with endothelial and bone marrow stromal cells, sensitivity to anticancer agents and radiation (growth inhibition), and tumorigenicity of CL-1 and CL-2 cells were determined and compared with these characteristics in parental LNCaP cells.

RESULTS

CL-1 and CL-2 cells are fast-growing cells when compared with parental LNCaP cells. They were capable of potentiating the growth of endothelial and bone marrow stromal cells in co-culture experiments and acquired significant resistance to radiation and to anticancer cytotoxic agents (Taxol paclitaxel, vinblastine, and etoposide). In contrast to the poorly tumorigenic parental LNCaP cells, CL-1 and CL-2 lines proved highly tumorigenic, exhibiting invasive and metastatic characteristics in intact and castrated mice or in female mice within a short period of 3 to 4 weeks. No growth supplements (e.g., Matrigel) were needed. When transfected with the green fluorescence protein (GFP) gene and transplanted orthotopically in the accessory sex gland, extensive metastatic disease from the primary CL tumor could be identified in bone, lymph nodes, lung, liver, spleen, kidney, and brain. Semiquantitative reverse transcriptase polymerase chain reaction analysis revealed a markedly distinct molecular expression profile in the CL lines: overexpression of basic fibroblast growth factor, interleukin-6, interleukin-8, vascular endothelial growth factor, transforming growth factor-beta, epidermal growth factor receptor, caveolin, and bcl-2 messenger RNAs and marked down-regulation of E-cadherin, p-53, and pentaerythritol tetranitrate.

CONCLUSIONS

Early administration of hormonal therapy after failure of first-line treatment is associated with a profound clonal selection of aggressive AI variants, such as CL-1 and CL-2 lines. These tumor lines, with their parental counterparts, can serve as valuable tools for studying the cellular and molecular mechanisms of CaP progression and metastasis under hormonal therapy. CL-1 and CL-2 offer a unique and reproducible model for the evaluation of drug sensitivity and for other therapeutic modalities for advanced prostate cancer.

Immunomodulatory dendritic cells generated from nonfractionated bulk peripheral blood mononuclear cell cultures induce growth of cytotoxic T cells against renal cell carcinoma

Dendritic cells (DCs) loaded with tumor antigens have the potential to become a powerful tool for clinical cancer treatment. Recently, the authors showed that a tumor-specific immune response can be elicited in culture via stimulation with autologous renal tumor lysate (Tuly)-loaded DCs that were generated from cytokine-cultured adherent peripheral blood mononuclear cells (PBMCs). Here, the authors show that immunomodulatory DCs can be generated directly from nonfractionated bulk PBMC cultures. Kinetic studies of DC differentiation and maturation in PBMC cultures were performed by monitoring the acquisition of DC-associated molecules using fluorescence-activated cell sorting analysis to determine the percentage of positive immunostained cells and the mean relative linear fluorescence intensity (MRLFI). Compared with conventional adherent CD14+ cultures, which have mostly natural killer, T, and B cells removed before cytokine culture, bulk PBMC cultures exhibited an early loss of CD14+ cells (day 0 = 78.8%, day 2 = 29.6% versus day 0 = 74%, day 2 = 75%) with an increase in yield of mature DCs (DC19- CD83+) (day 5 = 17%, day 6 = 21%, day 7 = 22% versus day 5 = 11%, day 6 = 15%, day 7 = 23%). Although a comparable percentage of DCs expressing CD86+ (B7-2), CD40+, and HLA-DR+ were detected in both cultures, higher expression levels were detected in DCs derived from bulk culture (CD86 = MRLFI 3665.1 versus 2662.1 on day 6; CD40 = MRLFI 1786 versus 681.2 on day 6; HLA-DR = MRLFI 6018.2 versus 3444.9 on day 2). Cytokines involved in DC maturation were determined by polymerase chain reaction demonstrating interleukin-6 (IL-6), IL-12, interferon-gamma, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha mRNA expression by bulk culture cells during the entire 9-day culture period. This same cytokine mRNA profile was not found in the conventional adherent DC culture. Autologous renal Tuly (30 micrograms protein/10(7) PBMCs) enhanced human leukocyte antigen expression by DCs (class I = 7367.6 versus 4085.4 MRFLI; class II = 8277.2 versus 6175.7 MRFLI) and upregulated cytokine mRNAs levels. Concurrently, CD3+ CD56-, CD3+ CD25+, and CD3+ TCR+ cell populations increased and cytotoxicity against autologous renal cell carcinoma tumor target was induced. Specific cytotoxicity was augmented when cultures were boosted continuously with IL-2 (20 U/mL biological response modifier program) plus Tuly stimulation. These results suggest that nonadherent PBMCs may participate in enhancing DC maturation. Besides the simplicity of this culture technique, bulk DC cultures potentially may be used with the same efficiency as conventional purified DCs. Furthermore, bulk culture-derived DCs may be used directly in vivo as a tumor vaccine, or for further ex vivo expansion of co-cultured cytotoxic T cells to be used for adoptive immunotherapy.

Presentation of renal tumor antigens by human dendritic cells activates tumor-infiltrating lymphocytes against autologous tumor: implications for live kidney cancer vaccines

The clinical impact of dendritic cells (DCs) in the treatment of human cancer depends on their unique role as the most potent antigen-presenting cells that are capable of priming an antitumor T-cell response. Here, we demonstrate that functional DCs can be generated from peripheral blood of patients with metastatic renal cell carcinoma (RCC) by culture of monocytes/macrophages (CD14+) in autologous serum containing medium (RPMI) in the presence of granulocyte macrophage colony-stimulating factor and interleukin (IL) 4. For testing the capability of RCC-antigen uptake and processing, we loaded these DCs with autologous tumor lysate (TuLy) using liposomes, after which cytometric analysis of the DCs revealed a markedly increased expression of HLA class I antigen and a persistent high expression of class II. The immunogenicity of DC-TuLy was further tested in cultures of renal tumor infiltrating lymphocytes (TILs) cultured in low-dose IL-2 (20 Biologic Response Modifier Program units/ml). A synergistic effect of DC-TuLy and IL-2 in stimulating a T cell-dependent immune response was demonstrated by: (a) the increase of growth expansion of TILs (9.4-14.3-fold; day 21); (b) the up-regulation of the CD3+ CD56- TcR+ (both CD4+ and CD8+) cell population; (c) the augmentation of T cell-restricted autologous tumor lysis; and (d) the enhancement of IFN-gamma, tumor necrosis factor-alpha, granulocyte macrophage colony-stimulating factor, and IL-6 mRNA expression by TILs. Taken together, these data implicate that DC-TuLy can activate immunosuppressed TIL via an induction of enhanced antitumor CTL responses associated with production of Thl cells. This indicates a potential role of DC-TuLy vaccines for induction of active immunity in patients with advanced RCC.

Adenovirus-mediated interleukin-2 production by tumors induces growth of cytotoxic tumor-infiltrating lymphocytes against human renal cell carcinoma

Combination therapy with interleukin-2 (IL-2) and tumor-infiltrating lymphocytes (TILs) demonstrates significant clinical activity in patients with metastatic renal cell carcinoma (RCC). To investigate whether local delivery of IL-2 via gene transfer is capable of improving the potency and efficacy of in vitro propagated TILs as compared with standard growth conditions [400 BRMP U (BU)/ml], a replication-deficient adenovirus expressing the human IL-2 gene under control of the cytomegalovirus (CMV) promoter (Ad-IL-2) has been constructed in our laboratory. RCC-TIL cultures were initiated by directly infecting RCC tumor suspension with Ad-IL-2 at a multiplicity of infection of 10:1. Subsequently the TIL cultures were restimulated with nonirradiated autologous RCC infected with Ad-IL-2 (RCC-Ad-IL-2) every 10 days (TIL/tumor = 50:1). Cell growth, phenotype, cytotoxicity, and cytokine messenger RNA (mRNA) expression were analyzed and compared with TIL growth stimulated with exogenous IL-2 (400 BU/ml). All five TILs tested responded to RCC-Ad-IL-2 activation, and a completed clearance of tumor cells was observed in cultures within 7-10 days. Lysis of nonirradiated RCC-Ad-IL-2 cells by TILs also was observed in cultures 3-5 days after restimulation. The IL-2 concentration in cell culture supernatants was maintained between 10 BU and 35 BU/ml (2 and 7 ng/ml), respectively. When compared with exogenous IL-2, RCC-Ad-IL-2 induced less growth expansion of TILs whereas a reduced CD56+ (23 +/- 14% vs. 44 +/- 13%; p < 0.05) but increased CD3+CD4+ cell population (32 +/- 11% vs. 15 +/- 6%; p < 0.05) with enhanced T cell-receptor use (59 +/- 10% vs. 42 +/- 7%; p < 0.005) was determined. An augmented human leukocyte antigen (HLA)-restricted and tumor-specific cytotoxicity was detected in RCC-Ad-IL-2-expanded TILs (day 35, 15.3 +/- 4.2 LU vs. 4.6 +/- 1.8 LU; p < 0.005). These properties were mediated by the CD8+ and CD4+ T-cell populations, as demonstrated by antibody-blocking assays. A unique cytokine profile also was detected in RCC-Ad-IL-2-induced TILs, which demonstrated an upregulation of both GM-CSF and IL-6 mRNA as compared with TILs expanded in the presence of exogenous IL-2. These data suggest that RCC-Ad-IL-2 is a potent immune stimulant that can be used in vitro as an immunogen to propagate cytotoxic RCC-TILs for adoptive immunotherapy or potentially in vivo by direct injection as a live tumor vaccine.

Highly efficient and consistent gene transfer into dendritic cells utilizing a combination of ultraviolet-irradiated adenovirus and poly(L-lysine) conjugates

Dendritic cells (DCs) are capable of presenting tumor-associated antigens and subsequently play an essential role in T-cell activation. The aim of this study was to develop an efficient method for gene transfer into DCs. These genetically transduced DCs can then be used as potent inducers of specific cell-mediated immune response. When compared with physical methods for gene transfer (lipofection and calcium phosphate precipitation), adenovirus (AdV) vectors proved to be highly efficient for gene transfer into DCs. To overcome concomitant AdV gene expression and potential immunogenicity, AdVs were irradiated with UV. The UV dose was optimized to block AdV transcription without altering AdV receptor binding and endocytosis capacity. We subsequently used a polycationic amino acid compound, poly(L-lysine), to conjugate the irradiated AdVs to transgenes. The resulting complexes were found to mediate a highly efficient transfer of transgenes into DCs, without concomitant expression of AdV gene products. Low titers of irradiated AdVs were sufficient for a consistent gene transfer into DCs. This is the first study to demonstrate efficient, consistent, and practical gene transfer using an UV approach to irradiated AdV-poly(L-lysine) conjugates and should be useful for the development of DC-based tumor vaccine therapies.

Sensitization of renal carcinoma to radiation using alpha interferon (IFNA) gene transfection

The rationale for this study was that local delivery of interferon-alpha (IFN-alpha) by gene transfection may be of value during radiotherapy. To investigate the feasibility of this approach, cells of the human renal carcinoma cell line R11 were transfected with the IFNA gene and evaluated for radiation responses in vitro by clonogenic assays. R11 cells expressing IFN-alpha after gene transfection were more sensitive to radiation than R11 control cells (SF2 = 0.33 and 0.51, respectively). In addition to increasing radiosensitivity, IFNA gene transfection slowed cellular growth and reduced the plating efficiency in clonogenic assays. The addition of exogenous rhIFN-alpha to cells at different times relative to irradiation showed that its presence during the postirradiation period was critical for radiosensitization, but repair of sublethal damage did not seem to be affected. No apoptosis of R11 cells was found 1-5 days after exposure to 2-25 Gy with or without IFN-alpha. Extensive formation of multinuclear giant cells was present beginning 2 days after irradiation; however, IFN-alpha did not cause any major alterations in the yield of radiation-induced giant cells. These studies suggest that gene transfection might be an effective means of delivering IFN-alpha for clinical use in radiotherapy of cancer.

Treatment of metastatic renal cell carcinoma with nephrectomy, interleukin-2 and cytokine-primed or CD8(+) selected tumor infiltrating lymphocytes from primary tumor

PURPOSE

Metastatic renal cell carcinoma is a disease with a mean survival of 6 to 10 months. Interleukin-2 (IL-2), the only approved therapy for metastatic renal cell carcinoma, is associated with a 14% response rate and durable remissions in some patients with high performance status. We performed a series of trials of IL-2 plus tumor infiltrating lymphocyte cell therapy and report the clinical results from 62 patients enrolled in these trials.

MATERIALS AND METHODS

Patients were eligible if they had metastatic renal cell carcinoma with the primary tumor in place and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were treated with cytokines before nephrectomy and preparation of cytokine primed tumor infiltrating lymphocytes or CD8(+) tumor infiltrating lymphocytes were isolated for infusion into patients. Of 62 patients enrolled 55 were treated with tumor infiltrating lymphocytes and IL-2, and were evaluable for toxicity, response and survival.

RESULTS

There were no postoperative mortalities. Of the patients 7 (11%) could not undergo systemic therapy. No unexpected IL-2 related toxicities or significant toxicities related to cell infusion were noted. Overall 5 patients (9.1%) achieved a complete response and 14 (25.5%) achieved a partial response. The responses were durable with a median duration of 14 months (range 0.8+ to 64+). The actuarial survival was 65% at 1 year and 43% at 2 years from the time of nephrectomy, with an overall median survival for all patients of 22 months (range 2 to 70+). The median survival for the responding patients has not yet been reached (range 2 to 63+).

CONCLUSIONS

These results demonstrate that immunotherapy with radical nephrectomy, tumor infiltrating lymphocytes, and IL-2 provides substantial clinical benefit in the majority of patients. Component cellular therapy with enriched cell fractions allows the administration of a more standardized cell product. The present results with nephrectomy, tumor infiltrating lymphocytes and IL-2 are encouraging, and a randomized clinical trial of nephrectomy, CD8(+) tumor infiltrating lymphocytes, plus IL-2 versus nephrectomy and IL-2 alone is currently in progress.

Identification of a positive regulatory element responsible for tissue-specific expression of prostate-specific antigen

The prostate-specific antigen (PSA) promoter (PSA-P) has been identified, characterized, and determined to be tissue specific. Compared with high expression of the genomic PSA gene in prostate cells, expression of the transgene driven by the putative PSA promoter is low. This suggests that the identified promoter may be incomplete or may function optimally with additional regulatory elements. To identify the presence of additional regulatory elements, we screened sequences upstream of the PSA promoter and identified a DNA fragment of 822 bp, which enhances PSA gene expression. Combining the newly identified PSA gene regulatory sequence (PSAR) with our previously identified PSA promoter (PCPSA-P) exhibited enhanced expressional activity in the PSA-producing LNCaP cell line. With the addition of 10 to 100 nM dihydrotestosterone, a more than 1000-fold increase in expression was observed as compared to androgen-negative controls. Furthermore, although the combined regulatory element (PSAR)-PSA promoter (PCPSA-P) sequence resulted in high transgene expression in LNCaP cell lines, the combined regulatory element-promoter sequence resulted in minimal expression in the non-PSA-producing prostate cell line PC-3, renal tumor cell line R11, and cervical adenocarcinoma cell line HeLa. The newly identified 822 bp alone could also function as a promoter. Compared with the combined promoter, however, the 822-bp fragment alone demonstrated lower activity and lower responsiveness to androgen stimulation. Our results suggest that coupling the PSA promoter with an upstream regulatory element results in a marked increase in PSA expression, suggesting that the complete PSA promoter contains two functional domains: a proximal promoter and a distal promoter, which can also function as an enhancer. The enhanced gene expression of the new construct, combined with its tissue specificity and androgen responsiveness, in turn provides a foundation for the development of tissue-specific vectors for prostate cancer gene therapy.

Quantitative polymerase chain reaction does not improve preoperative prostate cancer staging: a clinicopathological molecular analysis of 121 patients

PURPOSE

To improve on current staging and monitoring methods for prostate cancer, we applied the technique of quantitative polymerase chain reaction to measure the degree of tumor burden in the circulation and correlate this with pathological tumor stage. A reproducible, highly sensitive and specific, reverse transcriptase-polymerase chain reaction amplification technique to quantify prostate specific antigen (PSA) and prostate specific membrane antigen gene expression in the peripheral circulation was developed. Using a 32phosphorus-gamma-adenosine triphosphate-5'PSA and prostate specific membrane antigen primer incorporation assay, the ribonucleic acid signal extracted from a single neoplastic cell (LNCaP) premixed in 10 cc normal whole blood could be amplified. PSA and prostate specific membrane antigen polymerase chain reaction indexes have been created for clinical application.

MATERIALS AND METHODS

From September 1994 through July 1995 specimens from 121 patients were prospectively analyzed for PSA and prostate specific membrane antigen signals.

RESULTS

Circulating PSA producing cells were present in 29 of 33 patients (88%) with metastatic prostate cancer. Two of 19 patients (11%) with no known prostate cancer exhibited positive signals (1 later had prostate cancer), establishing a sensitivity of 88% and specificity of 94% for our assay. Positive PSA polymerase chain reaction signals were detected in 30 of 51 patients (59%) with stages pT1 and pT2 disease and in 13 of 18 (72%) with stage pT3 cancer. No statistically significant relationship of a positive PSA polymerase chain reaction signal to pathological stage, tumor grade, apical involvement or positive surgical margins was found, and no benefit was derived by measuring the quantity of circulating PSA polymerase chain reaction signals. Circulating prostate specific membrane antigen polymerase chain reaction signals were identified mostly in patients with advanced prostate cancer and offered no benefit to preoperative staging.

CONCLUSIONS

Given the high incidence of false positive signals in patients with pathologically determined localized disease, in our experience polymerase chain reaction based assays offer no immediate benefit for preoperative prostate cancer staging. The prognostic significance of detecting circulating prostate specific signals awaits longer followup in this cohort of patients, which is currently under study.

In vitro modulation of tumor progression-associated properties of hormone refractory prostate carcinoma cell lines by cytokines

BACKGROUND

Cytokines exert cytostatic and immunomodulatory effects on carcinoma cells. Growth inhibition of human prostate carcinoma by cytokines has been demonstrated both in vitro and in vivo, whereas the cellular and molecular changes in prostate carcinoma properties after cytokine treatment have never been characterized. We have thus investigated whether the intrinsic properties of prostate carcinoma cells that are associated with tumor development and progression can be altered by direct cytokine treatment.

METHODS

LNCaP, DU-145, and PC-3 cell lines were treated with tumor necrosis factor-alpha (TNF-alpha) (200 U/mL), interferon-gamma (IFN-gamma) (500 U/mL), human leukocyte interferon (IFN-alpha) (500 U/mL), and interleukin-2 (IL-2) (400 U/mL). The expression of (prostate-specific antigen [PSA] and prostate-specific membrane [PSM]), androgen receptor (AR), growth factors, oncogenes, collagenase, cell adhesion molecules, HLA antigens, cell adhesion to human bone marrow stroma, and cell growth were determined by quantitative polymerase chain reaction (PCR) analysis, fluorescence-activated cell sorter (FACS) analysis, and cell attachment and proliferation assays, and were compared with non-treated cells.

RESULTS

PCR analysis indicated that only LNCaP cells expressed PSA, PSM, and AR mRNA. Cytokine treatment did not alter PSM mRNA expression, whereas a 15-fold decrease in PSA and a 5-fold reduction in AR mRNA expression was detected in TNF-alpha-treated cells. The down regulation of PSA production was also demonstrated at the protein level in a dose-dependent fashion. A fivefold decrease in PSA mRNA was also detected in IL-2-treated LNCaP cells but without a reduction in AR. Down regulated epidermal growth factor receptor (EGF-R) and basic fibroblast growth factor (b-FGF) mRNA expressions were detected in TNF-alpha- and IFN-alpha-treated DU-145 and PC-3 cells, whereas, only reduced EGF-R expression was observed in LNCaP cells. IFN-gamma and IL-2 treatment down regulated the expression of collagenase Type IV mRNA in DU-145 and PC-3 cells, whereas tumor transforming growth factor-beta (TGF-beta) and IL-6 mRNA expressions did not exhibit any essential changes after cytokine treatment. A reduction in c-myc mRNA expression was observed in TNF-alpha- and IFN-alpha-treated cells, whereas no change in HER-2 expression was noted in any cytokine treated cells. Up regulated P-cadherin, but not E-cadherin, mRNA expression was detected in TNF-alpha- and IFN-gamma-treated PC-3 cells. FACS analysis revealed that all but IL-2-treated cells had enhanced HLA Class I expression, with the maximum effect seen in TNF-alpha-treated LNCaP cells (threefold increase). Up regulated HLA Class II expression was seen only in IFN-gamma-treated cells. All cytokine-treated DU-145 and PC-3 cells expressed reduced levels of alpha3, but not beta1, integrin. Up regulated of ICAM-1 expression was seen in all cytokine treated DU-145 and PC-3 cells, whereas no change in CD44 occurred. Cytokine treatment reduced the binding affinity of LNCaP and DU-145, but not of PC-3 cells, to human bone marrow stromal cells, and all cytokines but IL-2 showed a mild to moderate growth inhibition to prostate cancer cells, with a marked inhibition only observed in TNF-alpha-treated LNCaP cells.

CONCLUSIONS

Cytokine treatment can effectively alter several prostate carcinoma properties that are closely associated with tumor invasion and a metastatic phenotype, suggesting that immunotherapy via the local delivery of cytokines may have a potentially therapeutic role in the treatment of hormone-refractory prostate cancer through both direct and indirect antitumor mechanisms.

Natural immune reactivity-associated therapeutic response in patients with metastatic renal cell carcinoma receiving tumor-infiltrating lymphocytes and interleukin-2-based therapy

Combination therapy with systemically administered interleukin-2 (IL-2) and tumor infiltrating lymphocytes (TIL) demonstrates significant clinical activity in some patients with metastatic renal cell carcinoma (RCC). The objective of this study was to identify predictors of therapeutic response in patients with IL-2- and TIL-based immunotherapy. We characterized and compared immunologic properties of tumors, TILs, peripheral blood lymphocytes (PBLs) and sera of responding (R, n = 8) with nonresponding patients (NR, n = 9). Before undergoing nephrectomy, responding patients exhibited a higher percentage of circulating natural killer (NK) cells (CD56+ CD3-) (43 +/- 20%) as compared with nonresponders (18 +/- 16%) (p < 0.01). After nephrectomy, the CD56+ CD3-/CD56- CD3+ ratio in responding patients (pre: 2.60 +/- 2.24; post: 0.28 +/- 0.19; p < 0.05) significantly decreased and was similar to that of patients not responding to therapy (0.42 +/- 0.36). Sera from patients responding to immunotherapy, obtained before and after completion of therapy, contained natural killer (NK)-enhancing factor(s) that significantly enhanced the proliferation (3.2 x 10(3) +/- 25%/ 3.6 x 10(3) +/- 13% counts/min) and cytotoxicity [17.6 +/- 4.0/18.0 +/- 1.9 lytic units (LU)] of fresh PBLs as compared with normal serum (1.8 x 10(3) +/- 8% counts/min; 13.4 +/- 2.5 LU) or sera from nonresponders (1.6 x 10(3) +/- 25%/1.5 x 10(3) +/- 20% counts/min; 8.3 +/- 5.9/6.8 +/- 4.8 LU). In contrast to noncultured tumor suspension, IL-2 cultivation induced TIL growth, cytotoxicity, and multicytokine synthesis, and a complete clearance of tumor cells. No significant differences were observed between responders and nonresponders in the in vitro characteristics of tumor/TIL, which include the degree of intratumoral lymphocytic infiltrate, TIL expansion, specific lysis of autologous tumor, phenotype, expansion time, quantity of TIL infused, cytokine release, and degree of tumor aggressiveness. We conclude that clinical response to TIL and IL-2-based immunotherapy is associated with patients' baseline natural immune status. The percentage of circulating NK cells and the presence of serum NK-cell-enhancing factors may serve as potential predictors of response in patients with advanced RCC. The in vitro study of RCC-TIL suggests that activated TIL may provide a synergistic effect to that of administered IL-2 on activation of cellular immune response in situ, rendering a tumor eradication, while the clinical outcome is largely dependent on the pretreatment immune status of patient.

In vivo trafficking of adoptively transferred interleukin-2 expanded tumor-infiltrating lymphocytes and peripheral blood lymphocytes. Results of a double gene marking trial

Adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) and IL-2 appears to produce dramatic regressions in patients with metastatic melanoma and renal cancer. However, the in vivo mechanism of TIL function is not known. We conducted an UCLA Human Subject Protection Committee, Recombinant DNA Advisory Committee, and FDA-approved clinical trial using genetically-marked TIL to test the hypothesis that these cells have unique, tumor-specific in vivo trafficking patterns. TIL and PBL (as a control effector cell population) were isolated and expanded in parallel in vitro in IL-2-containing medium for 4-6 wk. During the expansion, TIL and PBL were separately transduced with the amphotropic retroviral vectors LNL6 and G1Na. Transduced TIL and PBL were coinfused into patients and their respective numbers measured in tumor, peripheral blood, and normal tissues; integrated provirus could be quantitated and distinguished by DNA PCR. Nine patients were treated (six melanoma, three renal) and received between 4.5 x 10(8) and 1.24 x 10(10) total cells. Both "marked" TIL and PBL could be detected circulating in the peripheral blood, in some patients for up to 99 d after infusion. Marked TIL and/or PBL could be detected in tumor biopsies in six of nine patients as early as day 6 and as late as day 99 after infusion. No convincing pattern of preferential trafficking of TIL vs. PBL to tumor was noted. Moreover, concurrent biopsies of muscle, fat, and skin demonstrated the presence of TIL/PBL in comparable or greater numbers than in tumor in five patients. The results of this double gene marking trial provide interesting insights into the life span and trafficking of adoptively transferred lymphocytes, but do not support the hypothesis that TIL specifically traffic to tumor deposits.

Prostate tissue specificity of the prostate-specific antigen promoter isolated from a patient with prostate cancer

We have cloned and characterized a 620-bp fragment of DNA that flanks 5' of the prostate-specific antigen (PSA) gene from a prostate cancer patient. Using DNA transfection, the efficacy of this putative promoter in regulating gene expression was quantitated in several prostate and nonprostate tissue cell lines. Our results demonstrated that the 620-dp DNA fragment actively drives gene expression in LNCaP, a PSA-producing prostate tumor cell line. No promoter activity was detected in the non-PSA-producing prostate tumor lines, DU145 and PC-3, nor in a renal (R11) or breast (MCF-7) cancer cell line. Furthermore, the promoter activity could be regulated in vitro by androgen stimulation. Dihydrotestosterone (DHT) concentrations between 3 and 30 nM induced the highest promoter activity in the transfected LNCaP cells, which parallels the expression profile of the androgen receptor in LNCaP cells. In addition, our PSA promoter exhibited competitive inhibition of the endogenous genomic PSA promoter in transfected LNCaP cells, suggesting that prostate cell-specific DNA-binding proteins are required to activate the PSA promoter. increased its potency four- to five-fold while retaining tissue specificity. Our data suggest that a strong tissue-specific negative regulatory element capable of overriding the nonspecific CMV promoter is present in the PSA promoter and confers its tissue specificity. The use of a highly specific promoter-driven gene vector will allow selective expression of therapeutic genes within PSA-producing prostate cancer cells, providing a unique strategy for prostate cancer gene therapy.

In vitro modulation of the invasive and metastatic potentials of human renal cell carcinoma by interleukin-2 and/or interferon-alpha gene transfer

BACKGROUND

Continuous local delivery of interleukin-2 (IL-2) and interferon-alpha (IFN-alpha) via gene transfer appears to be more effective than systemic therapy in preventing the growth of human renal cell carcinoma (RCC) in vitro and in vivo. To understand further if cytokine-gene transfection of RCC could alter certain cellular properties that are associated with the invasive and metastatic potentials of tumor, the authors characterized six cell lines that produce IL-2 and/or IFN-alpha in their expression of intercellular adhesion molecule-1 (ICAM-1) and CD44; binding affinity to extracellular matrix (ECM) components (fibronectin, laminin, type IV collagen, and vitronectin); and preference in forming homotypic aggregation and mRNA levels of c-myc, epidermal growth factor receptor (EGF-R), tumor transforming growth factor-beta (TGF-beta) and type IV collagenase. These six lines were compared with control vector transfected parental R11 line.

METHODS

The expression of ICAM-1 and CD44 was determined by fluorescence-activated cell sorter (FACS) analysis, the tumor cell binding affinity to ECM components was measured by cell attachment assay, the degree of homotypic aggregation was quantified by cell aggregation assay, and the mRNA levels of c-myc, EGF-R, TGF-beta, and collagenase were analyzed by a quantitative polymerase chain reaction analysis.

RESULTS

Both IL-2-gene- and IFN-alpha-gene-modified R11 exhibited enhanced expression of ICAM-1, suppression of CD44, and decreased binding affinity to ECM components, when compared with the R11-control vector. All cytokine-producing tumor lines showed a decreased preference to form homotypic aggregation. Interferon-alpha gene transfer downregulated c-myc, EGF-R, and type IV collagenase mRNA expression, whereas only the higher producers of IL-2 downregulated TGF-beta mRNA expression. Exogenous IL-2 and/or IFN-alpha treatment of a IFN-alpha-resistant RCC enhanced both HLA class I antigen and ICAM-1 expression and suppressed CD44 expression, but had no effect on tumor growth rate.

CONCLUSIONS

The local production of high concentrations of IL-2 and IFN-a at the tumor site may directly alter tumor properties associated with invasive and metastatic phenotypes of RCC. Interleukin-2 and/or IFN-alpha gene therapy may be an effective strategy for treatment of patients with advanced renal cancer.

Interferon-alpha primed tumor-infiltrating lymphocytes combined with interleukin-2 and interferon-alpha as therapy for metastatic renal cell carcinoma

Murine models demonstrate therapeutic synergy for the combination of interleukin-2, interferon-alpha and tumor-infiltrating lymphocytes. We treated 11 patients with metastatic renal cell carcinoma with a novel regimen consisting of in vivo primed tumor-infiltrating lymphocytes, interferon-alpha and interleukin-2. Patients received interferon-alpha before radical nephrectomy; in vivo primed tumor-infiltrating lymphocytes were isolated and expanded in vitro. Low dose continuous infusion interleukin-2 at a dose of 2 x 10(6) units per m.2 per day was administered for 96 hours during each treatment week and interferon-alpha was administered as a subcutaneous injection at a dose of 6 x 10(6) units per m.2 per day on days 1 and 4 of the interleukin-2 infusion. No therapy was given during the last 3 days of a treatment week. One course of therapy consisted of 3 weeks of therapy followed by 3 weeks of rest. Patients were treated until maximal response, disease progression or dose limiting toxicity. A maximum of 6 courses of therapy were administered. Eleven patients underwent interferon-alpha priming and subsequent radical nephrectomy. In vivo primed tumor-infiltrating lymphocytes were successfully expanded in all 11 patients with an expansion index of greater than 170. In vivo primed tumor-infiltrating lymphocytes maintained their lytic activity for greater than 5 to 8 weeks in culture as demonstrated in the 4-hour 51chromium release assay. Ten patients underwent multimodality biological therapy and 3 (30%, 95% confidence interval 6 to 65%) have achieved complete response (2 clinical and 1 surgical) with durations of 24+, 23+ and 5+ months. Patients with stable disease received no additional therapy. No deaths and no grade 4 toxicities occurred. Immunotherapy using a combination of interferon-alpha primed tumor-infiltrating lymphocytes, low dose continuous infusion interleukin-2 and interferon-alpha can induce significant and durable antitumor responses in some patients with advanced renal cell carcinoma.

Human renal carcinoma line transfected with interleukin-2 and/or interferon alpha gene(s): implications for live cancer vaccines

BACKGROUND

Combination therapy with systemically administered interleukin-2 (IL-2) and interferon alpha (IFN-alpha) has resulted in long-term objective remissions in 30% of patients with metastatic renal cell carcinoma (RCC), but toxic effects are clinically significant.

PURPOSE

We have thus investigated an alternative therapeutic approach--continuous intratumoral production of IL-2 and/or IFN-alpha by a cytokine-transfected human RCC tumor cell line.

METHODS

Plasmid vectors were used to transfect the R11 RCC line with the genes for human IL-2 and/or IFN-alpha by the calcium phosphate precipitation method. Biologic characteristics of the cytokine-transfected tumor cells were determined by assays of thymidine incorporation and cytotoxicity, fluorescence-activated cell-sorter analysis, Northern blotting, and in vivo studies in C3Hf/Sed/Kam mice rendered T-cell deficient.

RESULTS

The transfected cell lines produced the following amounts of cytokine per 10(6) cells per day: R11-IL-2 (220 U), R11-IFN-alpha (10,240 U), and R11-IL-2 + IFN-alpha (95 U + 1270 U, respectively). Gamma irradiation did not eliminate cytokine secretion. Morphology and growth rates were identical to those for the parental R11 cell line, except for IFN-alpha-producing clones, which showed significant growth inhibition. All cytokine-producing cells demonstrated increased susceptibility to cell killing by peripheral blood leukocytes (PBL). IFN-alpha producers exhibited enhanced HLA antigen expression and suppressed c-myc messenger RNA expression; when cocultured in vitro, they induced similar changes in parental R11 cells. IL-2 producers could stimulate growth and cytotoxicity of naive (i.e., freshly isolated, uncultured) and activated PBL. All cytokine-producing cells lost their tumorigenicity, as evidenced by failure to grow in the T-cell-depleted mice. When co-injected at a local site but not at a distant site, these cells prevented growth of parental R11 cells. Histologic examination of the injection sites revealed a substantial influx of macrophages. Intraperitoneal administration of IL-2 and/or IFN-alpha could not, however, prevent growth of the parental R11 tumors.

CONCLUSION

Local production of high concentrations of IL-2 and IFN-alpha at the tumor site is more effective in preventing tumor growth than systemic administration.

IMPLICATION

Continuous local delivery of cytokines via transfer of cytokine genes into tumor cells for use as live cancer vaccines is a novel strategy for manipulation of host-mediated antitumor immune response in patients with advanced RCC.

Simultaneous use of two retroviral vectors in human gene marking trials: feasibility and potential applications

Two Moloney murine leukemia virus (Mo-MLV)-based neoR retroviral vectors--LNL6 and G1Na--were used to transduce various human tumor-infiltrating lymphocytes (TIL) populations. These groups included bulk CD(8+)- and CD(4+)-enriched TIL from human renal cell carcinomas and melanomas. Transduction efficiencies averaged 5% for single 4-hr supernatant infections. Integrated provirus could be detected for up to 4 weeks of in vitro culture. LNL6 provirus could be distinguished from G1Na provirus using specific polymerase chain reaction (PCR) primers. A single neomycin phosphotransferase (neoR) gene copy could be detected in 10(5) TIL. Using quantitative PCR, the relative ratio of LNL6 to G1Na copies in the same sample could be determined even at low copy numbers. These preclinical studies demonstrate the feasibility of using two retroviral marking vectors in human gene therapy efforts.

Modulation of tumor-infiltrating lymphocytes derived from human renal cell carcinoma by interleukin-4

Current methods of expanding tumor-infiltrating lymphocytes (TILs) from renal cell carcinoma bulk cultures result in a heterogeneous population of cells with low tumor-killing specificity. To improve the yield of cells with higher autologous and lower nonspecific cytotoxicity, interleukin-4 (IL-4) was added to high (1,000 U/ml)- and low (20 U/ml)-dose IL-2 and compared to cultures grown without IL-4 for proliferation, phenotype, and cytotoxicity against targets including autologous and allogeneic tumors. When compared to culture in IL-2 alone, the addition of IL-4 improved overall expansion in both high-dose (mean fold expansion of 2,061 vs. 1,087) and low-dose (mean fold expansion of 1,904 vs. 262) IL-2. Enhancement of TIL proliferation was dependent on the timing of IL-4 addition to the culture; augmented growth occurred only when IL-4 was added with or following activation by IL-2. The phenotype consisted primarily of CD3+/CD4+ lymphocytes with a reciprocal reduction in CD56+/CD16+ cells. Finally, there was a significant reduction in nonspecific cytotoxicity against K-562, M-14, and allogeneic tumor targets, but no significant change against autologous tumor. We conclude that IL-4 has an important regulatory effect on the expansion of renal cell carcinoma TILs in IL-2 by the promoting growth of CD3+/CD4+ lymphocytes and inhibiting the growth and nonspecific cytotoxicity associated with LAK-like CD16+/CD56+ cells. These findings may be beneficial in extracting more potent effector cells from bulk TIL culture for use in clinical trials.

Regulatory effects of interleukin-7 on renal tumor infiltrating lymphocytes

Biological therapy using a combination of lymphokine and tumor infiltrating lymphocytes (TILs) is a new approach to the treatment of patients with advanced cancer. To improve the potency of TILs, new cytokines with T-cell stimulatory effects used alone or in combination with interleukin-2 (IL-2) are currently being investigated. We have studied the effect of interleukin-7 (IL-7) on TILs derived from renal cell carcinoma. Our data demonstrated that five of ten TILs proliferated in response to IL-7 alone. This proliferative response was 73-90% less than that obtained with IL-2 alone. The use of IL-7 plus IL-2 resulted in a 1.2- to 4.7-fold increase in proliferation of six of ten TILs compared with IL-2 alone. IL-7-driven TIL growth was consistently blocked by anti-IL-2, anti-IL-2R and anti-IL-7 antibodies (37.2%, 41.6% and 82.2% suppression, respectively). The expression of IL-2 receptors was also significantly increased in the presence of IL-7 or IL-7 phytohemagglutinin (40.6 + 3.8 and 72.5 + 1.5). In comparison with IL-2, IL-7 treatment was associated with a decrease in CD56 (46.3% +/- 19 vs 10% +/- 4.9) and increase in CD3 (29.3% +/- 12 vs 73% +/- 6.4) and CD4 (19.3% +/- 15 vs 58% +/- 10). These studies suggest that in some renal TILs, IL-7 and IL-2 can have a synergistic proliferative effect. The IL-7 stimulatory effect appears to be mediated via both an IL-2 pathway and an IL-7-independent pathway.

Interleukin-6 and renal cell cancer: production, regulation, and growth effects

Interleukin-6 (IL-6) is a recently characterized pleiotropic cytokine with antitumor activity. We investigated the production of IL-6 by renal cell cancer (RCC) and the growth effects of IL-6 on RCC. Using immunoperoxidase staining, cytoplasmic IL-6 was detected in four of four renal tumor lines and in tumor cells from freshly nephrectomized RCC. We found that IL-6 mRNA was expressed at basal culture conditions by seven of ten RCC tumor lines tested. Biologically active IL-6, as measured by the B9 assay, was produced by all ten RCC tumor lines. The addition of tumor necrosis factor alpha (TNF alpha) significantly augmented the expression of IL-6 mRNA in five RCC tumor lines (P less than 0.05). The combination of interferon gamma IFN gamma and TNF alpha further enhanced the augmented IL-6 mRNA accumulation seen with TNF alpha alone (P less than 0.05). TNF alpha also significantly stimulated the production of biologically active IL-6 (P less than 0.01). Furthermore, IFN gamma and TNF alpha were found to enhance IL-6 bioactivity synergistically (P less than 0.05). The growth effects of IL-6 on RCC were also investigated in two experimental systems: IL-6 was found to stimulate proliferative responses in six of six RCC tumor lines as measured by thymidine-uptake assays; however, only one of six tumor lines displayed an increase in proliferative response of greater than 21% (113%). The growth effect of IL-6 was further tested in clonogenic assays. One of the tumor lines tested displayed an enhanced growth response of up to 200%. We conclude that IL-6 is produced by RCC; this production is enhanced by TNF alpha with synergistic effects seen with IFN gamma at both mRNA and protein levels. In turn, IL-6 may have a modest stimulatory growth effect on certain RCC tumor lines.

Autologous tumor-specific cytotoxicity of tumor-infiltrating lymphocytes derived from human renal cell carcinoma

Conditions for generating and expanding cytotoxic tumor-specific, tumor-infiltrating lymphocytes (TIL) were studied to improve the efficacy of adoptive cancer immunotherapy. Thus, we have examined the growth and cytolytic patterns of bulk culture TIL from human renal cell carcinoma (RCC) cultured in low (20 U/ml) or high (1,000 U/ml) dose interleukin (IL)-2, with or without irradiated autologous tumor stimulation. By 55 days in culture, TIL grown in the presence of IL-2 without tumor stimulation lost their lytic activity, whereas those exposed to tumor stimulation maintained high levels of cytotoxicity against autologous and/or nonautologous tumor targets. Only TIL grown with low dose IL-2 and autologous tumor maintained long-term (over 4 months in culture) specific cytotoxicity against the autologous tumor, even upon cryopreservation and regrowth. These TIL were 88-97% and 80% positive for CD3 and CD8, with a persistent subset exhibiting CD4+ CD8+ double positive staining. Their specific cytotoxic activity was major histocompatibility complex Class I-restricted and inhibited by pretreating the TIL with anti-CD3 monoclonal antibody. TIL exposed to the four types of culture conditions, low or high dose IL-2, with or without irradiated autologous tumors, and exhibiting different lytic specificities, all expressed mRNA for interferon-gamma and tumor necrosis factor (TNF)-alpha, but not for IL-1-beta, IL-4, IL-6, and granulocyte-macrophage colony stimulating factor. The degree of TNF-alpha mRNA expression correlated with the degree of autologous tumor-specific cytotoxicity of these TIL. This initial report demonstrates that antigen-specific cytotoxicity against the autologous tumor does, in fact, exist within the RCC tumors.(ABSTRACT TRUNCATED AT 250 WORDS)