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Biomedical subjects

S Kamidono

Publications and source records attributed to S Kamidono.

At least 37 records · Page 2Linked to original sources
PubMed2001

Synergistic antitumor effect of ionomycin and cisplatin against renal cell carcinoma in vitro and in vivo.

Objectives. To characterize the synergistic antitumor effects of the calcium ionophore, ionomycin, and of cisplatin against human renal cell carcinoma cell line, ACHN, both in vitro and in vivo.Methods. The in vitro growth rate of ACHN after exposure to these compounds was measured, using the MTT assay. The apoptotic features in ACHN were evaluated by DNA ladder analysis and flow cytometric analysis. Bcl-2 and Bax expression levels in ACHN after treatment were examined by Western blot. The synergistic antitumor effects of ionomycin and cisplatin against the growth of established ACHN tumors in athymic nude mice were then tested.Results. The in vitro growth rate of ACHN was suppressed more by ionomycin and cisplatin in combination than by either alone. DNA ladder and fragmentation were more obvious when the cells were incubated with ionomycin and cisplatin together than with either reagent alone. Ionomycin treatment increased the expression level of Bax protein, whereas Bcl-2 expression was not influenced. Although an intraperitoneal injection of cisplatin or an intratumoral injection of ionomycin against subcutaneous ACHN tumors somewhat reduced tumorigenicity in nude mice, the effect was significantly enhanced by a combination of these drugs.Conclusions. The synergistic antitumor effects suggest that ionomycin-based therapy could be a novel therapeutic strategy with which to treat advanced renal cell carcinoma.

Animals↗
PubMed2001

Increased Fas ligand expression in the tumor tissue and serum of patients with testicular germ cell tumors with seminomatous elements.

OBJECTIVES: To measure the expression levels of Fas and Fas ligand (FasL) in testicular germ cell tumor (TGCT) and to determine whether the serum level of soluble FasL (sFasL) could be used as a marker for patients with TGCT. METHODS: The expression of Fas and FasL in 51 specimens obtained from patients with TGCT was examined by reverse transcriptase-polymerase chain reaction, and the results were confirmed by Western blot analysis. The serum levels of sFasL in 24 patients with TGCT were measured using an enzyme-linked immunosorbent assay system. RESULTS: Of 33 TGCT specimens that included seminomatous elements, Fas and FasL was expressed in 24 (73%) and 24 (73%), respectively. On the other hand, 10 (56%) and 2 (11%) specimens expressed Fas and FasL, respectively, in 18 TGCT specimens without seminomatous elements. Moreover, the serum levels of sFasL were significantly higher in patients with TGCT with a seminomatous element than in those without it. CONCLUSIONS: These results indicate that FasL is strongly expressed in tumor tissue and is present at high levels in the serum of patients with TGCT with a seminomatous element compared with those without it and that the serum levels of sFasL could be used as a novel diagnostic marker for TGCT with seminomatous elements.

Biomarkers, Tumor↗
PubMed2001

Transforming growth factor-beta1 expression in early biopsy specimen predicts long-term graft function following pediatric renal transplantation.

The main cause of late graft loss or declining long-term graft function is chronic allograft nephropathy (CAN), characterized by progressive interstitial fibrosis. Transforming growth factor (TGF)-beta1 plays a key role in fibrogenesis. We immunohistochemically investigated whether the degree of TGF-beta1 expression in early biopsy specimens routinely obtained from stable allografts at 100 d could predict fibrosis and graft dysfunction in the late phase. Patients were children with grafts from related donors. We immunohistochemically determined intracellular and extracellular expression of TGF-beta1 in the graft using LC antibody (LC) for intracellular TGF-beta1 and CC antibody (CC) for extracellular TGF-beta1. The change in creatinine clearance between 100 d and 3 yr after transplantation (DeltaCcr) was used as an index of long-term graft function. We also used image analysis to calculate the relative area involved by interstitial fibrosis in the trichrome-stained section of graft biopsy specimens at 100 d and 3 yr, designating the change as DeltaFI. DeltaCcr was -4.2+/-9.4 mL/min in subjects with minimal early immunoreactivity for CC and -20.5+/-15.9 mL/min in subjects with strong reactivity (p<0.05). DeltaCcr was -14.5+/-18.6 mL/min in subjects with minimal early immunoreactivity for LC and -11.7+/-12.8 mL/min in those with strong reactivity. DeltaFI in subjects with minimal CC reactivity (1.28+/-4.11%) tended to be lower than that in subjects with strong reactivity (8.45+/-15.47%). Neither fibrosis at 100 d nor DeltaFI differed between subjects with minimal and strong LC reactivity. Thus, strong extracellular TGF-beta1 expression in grafts at 100 d after transplantation is associated with a long-term decline in graft function and tends to be associated with increased graft fibrosis at 3 yr.

Adolescent↗
PubMed2001

Novel therapeutic strategy for advanced prostate cancer using antisense oligodeoxynucleotides targeting anti-apoptotic genes upregulated after androgen withdrawal to delay androgen-independent progression and enhance chemosensitivity.

Progression to androgen-independence remains the main obstacle to improving survival for patients with advanced prostate cancer. In this review, findings are summarized that have recently been demonstrated to establish novel therapeutic strategy targeting several genes playing functionally important roles after androgen withdrawal and during androgen-independent progression. The authors initially characterized changes in gene expression after androgen withdrawal in the androgen-dependent Shionogi and LNCaP tumor models using cDNA arrays. Based on these results, they focused on genes highly upregulated after androgen ablation (i.e. bcl-2, bcl-xL, TR.PM-2, IGFBP-5), which have anti-apoptotic or mitogenic activities, and thereby confer a resistance to androgen withdrawal as well as cytotoxic chemotherapy. The authors further demonstrated the efficacy of an antisense oligodeoxynucleotide (ODN) strategy for patients with advanced prostate cancer through the inhibition of target gene expression, resulting in a delay in the progression to androgen-independence by enhancing apoptotic cell death induced by androgen ablation and chemotherapy. The authors also showed the effectiveness of combined antisense ODN therapy and cytotoxic chemotherapy by achieving additive or synergistic effects. These findings provide a basic significance for the design of clinical studies using antisense ODN either alone or in combination with chemotherapeutic agents in patients with advanced prostate cancer.

Androgens↗
PubMed2001

Value of prostate specific antigen alpha1-antichymotrypsin complex for the detection of prostate cancer in patients with a PSA level of 4.1-10.0 ng/mL: comparison with PSA-related parameters.

BACKGROUND: The aim of the present study was to evaluate the usefulness of prostate specific antigen alpha1-antichymotrypsin complex (PSA-ACT) in the differential diagnosis of prostate cancer in patients with a PSA level of 4.1-10.0 ng/mL compared to several PSA- and PSA-ACT-related parameters. METHODS: Serum samples were obtained from 103 patients with no evidence of malignancy on biopsy and 29 with histologically confirmed prostate cancer. All patients had pretreatment serum PSA levels between 4.0 and 10.0 ng/mL. The different forms of serum PSA, including total PSA (tPSA), free PSA (fPSA) and PSA-ACT were measured using immunofluorometric techniques with different monoclonal antibodies against PSA and ACT. Furthermore, tPSA and PSA-ACT densities of the whole prostate (PSAD and ACTD, respectively) and the f-to-tPSA and the f-to-PSA-ACT ratios (F/T ratio and F/ACT ratio, respectively) were calculated. RESULTS: The differences between patients with prostate cancer and benign prostatic disease were significant with respect to all six parameters examined in this study. Analysis of receiver operating characteristics revealed that the areas under the curve for PSA-ACT, ACTD and the F/ACT ratio were larger than those for tPSA, PSAD and the F/T ratio, respectively. However, there were no significant differences in discrimination between benign and malignant diseases among these six parameters. CONCLUSIONS: In patients who have an intermediate serum PSA level, PSA-ACT and its associated parameters may not be significantly superior in the differential diagnosis between prostate cancer and benign prostatic diseases compared to tPSA and its traditional relatives.

Aged↗
PubMed2001

Expression of endothelial nitric oxide synthase in the Sertoli cells of men with infertility of various causes.

OBJECTIVE: To investigate how endothelial nitric oxide (eNOS) expression in the seminiferous tubules might be related to spermatogenesis, by examining eNOS expression in testicular tissue of patients infertile from various causes. PATIENTS AND METHODS: The study included five fertile men with a normal sperm concentration, nine patients with obstructive azoospermia, 20 with varicocele testes and eight with idiopathic azoospermia (Sertoli cell-only syndrome). Testicular biopsy specimens were examined by immunohistochemistry for eNOS protein expression, in addition to a routine pathological assessment. eNOS protein was detected using an eNOS monoclonal antibody. A Sertoli cell staining index (SSI) was defined as the ratio of stained Sertoli cells per total number of Sertoli cells, and was compared among the groups. RESULTS: eNOS was localized to Sertoli cells in the seminiferous tubules and Leydig cells in the interstium; although some degenerating germ cells stained, normal germ cells did not. The SSI was significantly lower in patients with Sertoli cell-only syndrome than in either fertile men or patients with obstructive azoospermia or varicocele. However, the SSI did not correlate significantly with the Johnsen score. CONCLUSION: The expression of eNOS in Sertoli cells may depend on the existence of germ cells and be associated with germ cell development.

Adult↗
PubMed2001

Bladder reconstruction with autotransplanted ileum in the dog: better functional results than standard enterocystoplasty.

OBJECTIVE: To compare, in a dog model, the properties of a reconstructed bladder (peristalsis, histological changes and absorption) using an autotransplanted ileal segment with standard enterocystoplasty. MATERIALS AND METHODS: Female beagle dogs were divided into two groups. In group 1 (autotransplantation, six dogs), a Heineke-Mikulicz-type pouch was constructed using autotransplanted terminal ileum. The artery and vein of the terminal ileum were anastomosed to the iliac artery and vein, respectively. The pouch was anastomosed to the bladder remnant immediately above the vesical triangle. In group 2 (control, five dogs) the same type of bladder reconstruction using terminal ileum was undertaken but with no vessel anastomosis. Bladder function in these two groups was then compared for peristalsis (by monitoring intravesical pressure), histological changes (by microscopy) and glucose reabsorption (by measuring the amount of glucose remaining in the reconstructed bladder). The mean (range) follow-up was 11 (7-18) months for group 1 and 9.2 (7-12) months for group 2; the recovery time before examination was 4.6 (2-7) months for group 1 and 4.0 (2-6) months for group 2. RESULTS: In group 1, there were no major complications in five dogs after the procedure and they survived for > 7 months; the autotransplant became necrotic in one dog where the arterial diameter was < 1 mm. In the control group, all five dogs survived for > or = 7 months after surgery. Intestinal peristalsis was inhibited in group 1 but not in group 2. The bladder was oval/spherical in group 1 and elongated in group 2, with a thinner epithelium and fewer goblet cells in the latter. Glucose reabsorption was greater in group 2 than in group 1. CONCLUSION: Bladder reconstruction using autotransplanted terminal ileum in dogs is technically feasible. For bowel peristalsis and reabsorption of glucose, autotransplanted ileum may have functional advantages over a standard enterocystoplasty.

Absorption↗
PubMed2001

Value of the serum prostate-specific antigen-alpha 1-antichymotrypsin complex and its density as a predictor for the extent of prostate cancer.

OBJECTIVE: To determine whether serum levels of the prostate-specific antigen-alpha1-antichymotrypsin complex (PSA-ACT) and its density (ACTD) in patients scheduled to undergo radical prostatectomy for clinically localized prostate cancer can predict organ-confined vs extraprostatic disease. PATIENTS AND METHODS: Serum samples were obtained from 62 patients with clinically localized prostate cancer before they underwent radical prostatectomy. PSA and PSA-ACT were measured using immunofluorometric techniques with different monoclonal antibodies against PSA and ACT, respectively. Furthermore, the PSA and PSA-ACT densities of the whole prostate (PSAD and ACTD, respectively) were calculated. The relationships of serum PSA, PSA-ACT, PSAD, ACTD and the pathological stage of the prostatectomy specimens were analysed. RESULTS: The disease was organ-confined or extraprostatic in 30 and 32 men, respectively. In men with organ-confined cancer, the mean PSA and PSA-ACT levels were significantly lower than in those with extraprostatic disease. Furthermore, there were significantly higher mean PSAD and ACTD levels in men with extraprostatic than with organ-confined disease. There were also significant differences in PSA, PSA-ACT, PSAD and ACTD levels at each pathological stage, whereas there was no significant association between these variables and the Gleason score. Receiver-operating characteristic curve analysis for detecting organ-confined disease showed that PSA-ACT and ACTD had a larger area under the curve than PSA and PSAD, respectively, but these differences were not significant. Furthermore, PSA-ACT and ACTD provided significantly better sensitivity for detecting organ-confined disease than PSA and PSAD, respectively. CONCLUSIONS: Measuring PSA-ACT and ACTD may improve the preoperative evaluation of patients scheduled to undergo radical prostatectomy, because these factors better differentiate extraprostatic from organ-confined disease than PSA and PSAD.

Aged↗
PubMed2001

Renal cell carcinoma with extension of tumor thrombus into the vena cava: surgical strategy and prognosis.

PURPOSE: The outcome of patients who underwent radical resection of renal cell carcinoma extending into the vena cava was retrospectively analyzed, and risk factors for long-term survival were investigated. METHODS: From 1983 to 1999, 33 patients who had renal cell carcinoma with inferior vena caval tumor extension underwent 34 surgical procedures. There were 27 men and six women with an average age of 60.1 years. Twenty-two cases (64.7%) were classified as stage III (T1-2 N1 M0 or T3 N0-1 M0), and 12 cases (35.3%) as stage IV (T4 or N2-3 or M1). Coexistent lung metastasis was found in seven cases (20.6%). The tumor thrombi invaded into the inferior vena cava below the hepatic hilum in 19 cases, below the orifice of hepatic veins in 12, and above the diaphragm in 3. Cardiopulmonary bypass graft was applied in 13 cases (38.2%). Inferior vena cava was reconstructed by direct suture (n = 19), polytetrafluoroethylene patch angioplasty (n = 13), or graft replacement (n = 2). RESULTS: Two patients died during the early postoperative period because of retrohepatic caval injury and intraoperative pulmonary embolism. Late death occurred in 16 patients; the causes of death were tumor recurrence in 15 and acute pulmonary embolism as a result of graft thrombosis in 1. Overall 1-, 5-, and 10-year survival rates were 70%, 44%, and 26.4%, respectively. One- and 5-year survival rates were 81.3% and 52.9% for stage III and 50% and 31.2% for stage IV; a statistically significant correlation was found between surgical staging and survival (P =.049). Patients without lymph node metastasis had a significant survival advantage over those with lymph node metastasis (P =.022). There was no significant difference in survival on the basis of the presence or absence of synchronous lung metastasis (P =.291). The degree of local extension of the tumor or the level of tumor thrombus did not tend to influence survival. CONCLUSIONS: Surgical prognosis in patients with renal cell carcinoma extending into the vena cava was determined by the staging of the tumor, especially lymph node status, and not by the level of tumor thrombus or the presence of concurrent lung metastasis. The use of cardiopulmonary bypass graft is recommended for the resection of tumor thrombus extending over the diaphragm.

Adult↗
PubMed2001

Usefulness of Ureteropyeloscopy for diagnosis of upper urinary tract tumors.

BACKGROUND: Upper urinary tract tumors have historically been diagnosed using urinary cytology examination and radiography. As the technique and instrumentation of ureteroscopic inspection and biopsy have advanced, ureteroscopic examination has become more routine. We studied the applicability and safety of using ureteropyeloscopy to diagnose upper urinary tract tumors. PATIENTS AND METHODS: Between January 1994 and October 1999, 50 patients at Kobe University Hospital underwent ureteropyeloscopy for suspected upper urinary tract tumors. RESULTS: The sensitivity values of radiography, urinary cytology, and ureteroscopy were 96%, 60%, and 92%, respectively. The specificity values of the three procedures examination were 12%, 84%, and 88%, respectively. No major complications or dissemination of malignant cells were evident. CONCLUSION: Ureteroscopic examination is a safe, sensitive, and specific means of detecting upper urinary tract tumors.

Adult↗
PubMed2001

Gene therapy for bladder cancer using adenoviral vector.

BACKGROUND AND PURPOSE: Bladder cancer is common. Current treatment for patients with superficial bladder cancer involves transurethral resection followed by adjuvant bacillus Calmette-Guérin (BCG) administration. Adjuvant BCG has been reported to be effective in 38% to 68% of patients; however, more than 30% of patients do not respond. Because p53 mutations are common among superficial bladder cancers, we tested the feasibility of using p53 as a gene therapy agent for targeting superficial tumors, which are easily accessible using an intravesical approach. MATERIALS AND METHODS: Wild-type p53 was transduced into various human and murine bladder cancer cell lines (HTB9, KU-1, and MBT-2) using a recombinant adenoviral vector (Ad5CMV-p53) in vitro. Also, subcutaneous tumors were established and then treated with intratumoral injection of Ad5CMV-p53 or control viruses. RESULTS: In vitro assays revealed significant growth suppression of target cells by Ad5CMV-p53 in comparison with those receiving the control Ad5-CMV-PA vector or untreated control cells. In vivo studies using subcutaneous bladder tumor models established in syngeneic mice demonstrated that the rate of tumor growth and volume was reduced to a greater extent by 14 days of intratumoral injection of Ad5CMV-p53 rather than Ad5CMV-PA. Furthermore, the survival of host animals bearing tumors that were infected with Ad5CMV-p53 was significantly longer than that of the control group treated with Ad5CMV-PA (P < 0.01). CONCLUSION: Our data suggest that Ad5CMV-p53 is effective in suppressing bladder cancer growth and improving host survival.

Adenoviridae↗
PubMed2001

Acquisition of resistance to Fas-mediated apoptosis by overexpression of clusterin in human renal-cell carcinoma cells.

Recent studies have shown the antiapoptotic activity of clusterin against a wide variety of stimuli; however, the functional role of clusterin in Fas-mediated apoptosis has not been well characterized. We transfected the clusterin cDNA into human renal-cell carcinoma (RCC) ACHN cells that scarcely express clusterin protein in order to examine whether overexpression of clusterin inhibits the Fas-mediated signal pathway for apoptotic cell death. No significant difference was observed in the in vitro cell growth rates between the clusterin-transfected cell line (ACHN/CL) and the vector-only-transfected control cell line (ACHN/C), whereas the colony-forming efficiency in soft agar of ACHN/CL was significantly higher than that of ACHAN/C. The anti-Fas monoclonal antibody CH11 induced apoptosis in ACHAN/C cells in a dose-dependent manner; however, the growth-inhibitory effect of CH11 on ACHN/CL cells was markedly suppressed, with corresponding increases in p53 expression and decrease in the fraction of cells in the sub-G(1) phase of the cell cycle. Furthermore, the cytotoxic effect of CH11 on ACHN/CL cells was augmented by treatment with interferon-gamma, but a corresponding effect on ACHN/C cells was not observed. These findings suggest that overexpression of clusterin may contribute to a phenotype resistant to Fas-mediated apoptosis, and that if interferon-gamma treatment is added according to the clusterin expression level, Fas-mediated therapy could be a novel approach to RCC.

Adult↗
PubMed2001

Significance of serum inhibin B concentration for evaluating improvement in spermatogenesis after varicocelectomy.

BACKGROUND: The study aim was to clarify the relationship of serum inhibin B concentrations to recovery of spermatogenic function after varicocelectomy, both as a predictor of improvement in the seminogram and as a means of monitoring hormonal function after surgery. METHODS: Fifty-two varicocele patients, including five with normal sperm concentrations, were studied. Changes in the seminogram, serum hormone concentrations and serum inhibin B were evaluated in the 47 oligozoospermic patients after surgery. Preoperative inhibin B concentrations correlated significantly with serum concentrations of FSH (r = 0.598, P < 0.0001) and testosterone (r = 0.380, P < 0.02). Inhibin B concentrations also correlated significantly with sperm concentration (r = 0.351, P < 0.02) and total testicular volume (r = 0.578, P < 0.0001). No significant correlation was seen between inhibin B and the Johnsen score. Preoperative concentrations of inhibin B were higher in patients who increased their sperm concentration after surgery (responders) than in those without improved concentrations (non-responders). No significant difference was observed between pre- and postoperative inhibin B concentrations in responders or non-responders. However, 15 of 25 (60%) patients with increased inhibin B showed improvement of the seminogram, while only five of 22 (23%) patients with no change or a decrease in inhibin B had any improvement (P < 0.05). CONCLUSIONS: Preoperative serum inhibin B concentration could not reliably predict a response to varicocelectomy. However, a change in serum inhibin B concentration after varicocelectomy might be helpful to evaluate the improvement of testicular function after varicocelectomy.

Adult↗
PubMed2001

Prognostic variables in patients who have undergone radical cystectomy for transitional cell carcinoma of the bladder.

OBJECTIVE: To evaluate whether several clinicopathological factors could be used as prognostic predictors in patients who have undergone radical cystectomy for transitional cell carcinoma (TCC) of the bladder. METHODS: Between January 1985 and June 2000, 154 patients underwent radical cystectomy and pelvic lymphadenectomy for TCC of the bladder at a single institution. Their clinicopathological findings were analyzed based on the criteria of the Japanese Urological Association. RESULTS: Histopathological examination revealed that the tumor grade was 1 or 2 in 22 patients and 3 in 132 patients; the pathological stage was pT1 or less in 30 patients, pT2 in 51 patients, pT3 in 53 patients and pT4 in 20 patients. Vascular involvement and lymph node metastasis were found in 85 and 33 patients, respectively. The cause-specific 5-year survival rate was 64.2% for all patients, 74.4% for patients with grade 1 or 2 tumors, 62.9% for those with grade 3 tumors; 90.9% for those with stage pT1 or less, 77.9% for those with stage pT2, 45.0% for those with stage pT3 and 29.2% for those with stage pT4 (p < 0.001); 83.2% for patients without vascular involvement and 42.0% for those with vascular invasion (p < 0.001); and 76.5% for patients without lymph node metastasis and 22.7% for those with lymph node metastasis (p < 0.001). Multivariate analysis revealed a strong independent correlation of the pathological stage and lymph node metastasis with poor prognosis and, furthermore, the incidence of lymph node metastasis was significantly related to the increase in pathological stage. CONCLUSIONS: In this series, the pathological stage, lymph node metastasis and vascular involvement, but not tumor grade, were significantly useful prognostic factors in patients who have undergone radical cystectomy for TCC and among them only pathological stage and lymph node metastasis could be used as independent predictors for poor prognosis.

Adult↗
PubMed2001

Significance of prostate-specific antigen--alpha(1)-antichymotrypsin complex for diagnosis and staging of prostate cancer.

OBJECTIVE: To evaluate the clinical significance of measuring the prostate-specific antigen-alpha(1)-antichymotrypsin (PSA-ACT) for differentiating prostate cancer from benign prostate hypertrophy (BPH) and for the staging of prostate cancer. METHODS: Before treatment, total PSA (tPSA) and PSA-ACT were measured in 120 patients with prostate cancer and in 150 patients with BPH using immunofluorometric techniques with different monoclonal antibodies against PSA and ACT. Furthermore, the tPSA and PSA-ACT densities of the whole prostate (PSAD and ACTD, respectively) were calculated. RESULTS: tPSA, PSAD, PSA-ACT and ACTD levels in patients with prostate cancer paralleled the clinical stage and were significantly higher than those in patients with BPH. Furthermore, these four values were significantly higher in patients with pathologically extraprostatic disease than those with organ-confined disease. Receiver operating characteristics analysis among patients with PSA values of 4.1-10 ng/ml revealed that the areas under the curve for tPSA and ACTD were similar to those for PSA-ACT and ACTD, respectively and that no significant differences in the differentiation between prostate cancer and BPH were observed among these parameters. CONCLUSIONS: Measurement of PSA-ACT provides useful information for the clinical staging of prostate cancer and differential diagnosis between prostate cancer and BPH; however, compared with tPSA, PSA-ACT may not be significantly superior in the diagnosis and staging of prostate cancer.

Diagnosis, Differential↗
PubMed2001

Secreted type of modified interleukin-18 gene transduced into mouse renal cell carcinoma cells induces systemic tumor immunity.

PURPOSE: Interleukin (IL)-18 is a novel cytokine that has been identified as a strong interferon-gamma inducer. IL-18 has bioactivity similar to that of IL-12 and demonstrates antitumor effects. Since IL-18 does not have a signal sequence, we constructed the gene, consisting of the signal sequences of interferon-beta and mature IL-18 complementary (c) DNA. The modified gene was subsequently transduced into a mouse renal cell carcinoma cell line to induce IL-18 secretion from tumor cells to establish whether this IL-18 secreting tumor cell line may induce systemic tumor immunity. MATERIALS AND METHODS: Modified IL-18 cDNA consisting of the signal sequences of interferon-beta and mature type of IL-18 cDNA was constructed by the overlap extension method. The modified and original IL-18 cDNA was transduced into the RenCa mouse renal cell carcinoma cell line. Expression of IL-18 messenger RNA and concentration of IL-18 in the culture supernatant were determined. Direct antitumor and tumor vaccine effects were investigated in syngeneic Balb/c mice. To determine the mechanism of the antitumor effect immunodeficient mice were challenged with IL-18 secreting RenCa cells. RESULTS: Although the modified and original IL-18 genes transduced RenCa showed almost the same level of IL-18 messenger RNA expression, only RenCa cells transduced with modified IL-18 gene secreted IL-18 into the culture supernatant and were completely rejected when transplanted into syngeneic mice. T lymphocytes were involved in this antitumor effect. Moreover, the modified IL-18 transduced RenCa induced tumor vaccine effect against parental RenCa cells injected at a distant site. CONCLUSIONS: Immune gene therapy using modified IL-18 cDNA appears to be effective and IL-18 secreting cancer cells may be a candidate for tumor vaccine therapy.

Animals↗