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Biomedical subjects

A Belldegrun

Publications and source records attributed to A Belldegrun.

At least 19 recordsLinked to original sources
PubMed2006

Joint association of polymorphism of the FGFR4 gene and mutation TP53 gene with bladder cancer prognosis.

The impact of the fibroblast growth factor receptor 4 (FGFR4) Gly388Arg polymorphism on bladder cancer is unknown. We found no clear correlations between the FGFR4 genotype and risk of bladder cancer or pathological parameters. Neither the polymorphism nor TP53 mutation status was an independent predictor of prognosis, but they might act jointly on the disease-specific survival of patients.

Aged↗
PubMed2001

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.

Animals↗
PubMed2001

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.

CD4-Positive T-Lymphocytes↗
PubMed2001

Society of Urologic Oncology Biotechnology Forum: new approaches and targets for advanced prostate cancer.

PURPOSE: We provide an overview of advances in molecular based therapeutic strategies for prostate cancer and summarize the studies presented at the Society of Urologic Oncology Biotechnology Forum in 2000. MATERIALS AND METHODS: Three promising new treatment strategies are presented, and a critique of the advantages and limitations of each is offered by a leading expert in the field. RESULTS: Treatment results and the current state of dendritic cell based immunotherapy, monoclonal antibody therapy and anti-apoptotic treatment approaches are presented. CONCLUSIONS: Currently patients with advanced prostate carcinoma have expanded therapeutic options available in the form of molecular based phases II and III clinical trials.

Antibodies, Monoclonal↗
PubMed2001

New biologicals for prostate cancer prevention: Genes, vaccines, and immune-based interventions.

For at least 100 years, immunologists have proposed activating the immune system to specifically target and eradicate autologous tumor cells. The idea that tumor cells can be recognized as foreign to the host's immune system is an essential concept of tumor immunology that was first postulated by Paul Ehrlich at the turn of the century. Anecdotal reports of spontaneous tumor regression have been presumed to be immunologically mediated. With the advent of molecular gene transfer techniques and increased knowledge of the regulation of the immune response, effective methods for harnessing the immune system as a therapeutic agent are finally being realized. Current results of clinical immune/gene therapy protocols will be reviewed with consideration towards the concept of cancer prevention.

Clinical Trials, Phase I as Topic↗
PubMed2001

Chimeric PSA enhancers exhibit augmented activity in prostate cancer gene therapy vectors.

The native PSA enhancer and promoter confer prostate-specific expression when inserted into adenovirus vectors capable of efficient in vivo gene delivery, although the transcriptional activity is low. By exploiting properties of the natural PSA control regions, we have improved the activity and specificity of the prostate-specific PSA enhancer for gene therapy and imaging applications. Previous studies have established that androgen receptor (AR) molecules bind cooperatively to AREs in the PSA enhancer core (-4326 to -3935) and act synergistically with AR bound to the proximal promoter to regulate transcriptional output. To exploit the synergistic nature of AR action we generated chimeric enhancer constructs by (1) insertion of four tandem copies of the proximal AREI element; (2) duplication of enhancer core; or (3) removal of intervening sequences (-3744 to -2855) between the enhancer and promoter. By comparing to the baseline construct, PSE, containing the PSA enhancer (-5322 to -2855) fused to the proximal promoter (-541 to +12), the three most efficacious chimeric constructs, PSE-BA (insertion of ARE4), PSE-BC (duplication of core) and PSE-BAC (insertion of core and ARE4), are 7.3-, 18.9-, and 9.4-fold higher, respectively. These chimeric PSA enhancer constructs are highly androgen inducible and retain a high degree of tissue discriminatory capability. Initial biochemical studies reveal that the augmented activity of the chimeric constructs in vivo correlates with their ability to recruit AR and critical co-activators in vitro. The enhanced activity, inducibility and specificity of the chimeric constructs are retained in an adenoviral vector (Ad-PSE-BC-luc). Systemic administration of Ad-PSE-BC-luc into SCID mice harboring the LAPC-9 human prostate cancer xenografts shows that this prostate specific vector retained tissue discriminatory capability compared with a comparable cytomegalovirus (CMV) promoter driven vector.

Adenoviridae↗
PubMed2001

Gene and immune therapy for renal cell carcinoma.

Conventional therapy for metastatic renal cell carcinoma is associated with a poor response rate and few patients are long-term survivors. The occurrence of spontaneous regression and the prolonged latency period between primary tumor removal and the appearance of metastases in some patients suggest the existence of important host immune responses to autologous tumor cells. With the advent of molecular gene transfer techniques and increased knowledge of the basic pathways of immune activation, the field of cancer immunotherapy has finally begun to develop novel and effective approaches for harnessing the immune system as a therapeutic agent. Current immunotherapy and gene therapy strategies, including methods of cytokine delivery and tumor-cell-based vaccines, are presented.

Cancer Vaccines↗
PubMed2001

Biology of renal cell carcinoma: changing concepts in classification and staging.

Advances in our understanding of the pathogenesis, behavior, and importance of prognostic factors for renal cell carcinoma (RCC) have paved the way for increased sophistication in its classification and staging. In the past, lack of consistent classification and terminology for RCC histology and staging has complicated comparability of clinical studies looking at patient prognosis and response to treatment. In this review, the results of international consensus efforts to achieve uniform classification systems for RCC are outlined and some future directions are considered.

Carcinoma, Renal Cell↗
PubMed2000

Treatment of a patient by vaccination with autologous dendritic cells pulsed with allogeneic major histocompatibility complex class I-matched tumor peptides. Case Report.

Dendritic cells (DCs) are antigen-presenting cells that play a central role in the initiation and modulation of antitumor immune responses. In this pilot study, we investigated the ability of autologous DCs pulsed ex vivo with allogeneic major histocompatibility complex class I-matched glioblastoma peptides to stimulate host antitumor immune responses when injected as a vaccine. A patient with recurrent brainstem glioblastoma multiforme (GBM) received a series of three intradermal immunizations of antigen-pulsed DCs on an outpatient basis following surgical debulking of her posterior fossa tumor. Dendritic cell vaccination was well tolerated, and no clinical signs of autoimmunity or experimental allergic encephalomyelitis were detected. She developed a measurable cellular immune response against the allogeneic glioblastoma peptides used in her vaccine preparation, as demonstrated by in vitro T-cell proliferation assays. In addition, increased T-cell infiltration was noted within the intracranial tumor site in the biopsy sample obtained following DC vaccination. An objective clinical response, however, was not evident, and this patient eventually died 21 months after her disease was diagnosed. To our knowledge, this is the first patient with brain cancer ever to be treated with DC-based immunotherapy. This case illustrates that vaccination with DCs pulsed with acid-eluted glioblastoma peptides is feasible and can induce systemic antigen-specific immunity in a patient with recurrent GBM. Additional studies are necessary to determine the optimum DC doses and antigen loading conditions that may translate into clinical effectiveness and survival benefit for patients with brain tumors. Phase I trials for malignant glioma are currently underway.

Antigens, Neoplasm↗
PubMed2000

WISH-PC2: a unique xenograft model of human prostatic small cell carcinoma.

Prostatic small cell carcinoma is an aggressive subtype of prostate cancer that usually appears as a progression of the original adenocarcinoma. We describe here the WISH-PC2, a novel neuroendocrine xenograft of small cell carcinoma of the prostate. This xenograft was established from a poorly differentiated prostate adenocarcinoma and is serially transplanted in immune-compromised mice where it grows within the prostate, liver, and bone, inducing osteolytic lesions with foci of osteoblastic activity. It secretes to the mouse Chromogranin A and expresses prostate plasma carcinoma tumor antigen-1, six-transmembrane epithelial antigen of the prostate, and members of the Erb-B receptor family. It does not express prostate-specific antigen, prostate stem cell antigen, prostate-specific membrane antigen, and androgen receptor, and it grows independently of androgen. Altogether, WISH-PC2 provides an unlimited source in which to study the involvement of neuroendocrine cells in the progression of prostatic adenocarcinoma and can serve as a novel model for the testing of new therapeutic strategies for prostatic small cell carcinoma.

Adenocarcinoma↗
PubMed2000

Prognostic indicators for renal cell carcinoma: a multivariate analysis of 643 patients using the revised 1997 TNM staging criteria.

PURPOSE: We determine independent prognostic indicators for renal cell carcinoma using the revised 1997 TNM staging criteria. MATERIALS AND METHODS: The records of 643 consecutive patients undergoing partial or radical nephrectomy at our institution between 1987 and 1998 were reviewed. Preoperative evaluation of functional status using the Eastern Cooperative Oncology Group (ECOG) criteria was performed in all cases. Renal cell carcinoma grade and stage were evaluated using the 1997 American Joint Committee on Cancer grading and TNM staging criteria, respectively. Patients were followed for a mean plus or minus standard deviation of 47+/-40 months (median 87). Kaplan-Meier survival curves were used to determine 5-year cancer specific survival for all patient groups. Univariate analysis using log rank sum tests was performed to evaluate the prognostic significance of overall TNM stage, tumor stage, disease grade and ECOG status. Multivariate analysis was performed to determine which factors had an independent impact on survival of patients with renal cell carcinoma. RESULTS: The 5-year cancer specific survival rate was 91%, 74%, 67% and 32% for TNM stages I, II, III and IV lesions, respectively (p<0.001). Analysis demonstrated a survival rate of 83% for stage T1, 57% for stage T2, 42% for stage T3 and 28% for stage T4 disease (p<0.001), and 89% for grade 1, 65% for grade 2, and 46% for grades 3 and 4 (p<0.001). Multivariate analysis revealed that overall TNM stage and grade of disease were the most important prognostic indicators for renal cell carcinoma (p<0.001). ECOG classification was a less significant predictor (p = 0.031) and tumor stage was not shown to have any independent impact on patient survival (p = 0.138). CONCLUSIONS: Better survival rates of patients with localized and advanced renal cell carcinoma can be demonstrated with recent advances in diagnosis and treatment. The revised 1997 TNM criteria manifest an appropriate adjustment in staging renal cell carcinoma based on these improvements, with overall stage correlating with cancer specific survival. In contrast, while effectively predicting survival, tumor stage did not demonstrate an independent impact on renal cell carcinoma prognosis under multivariate analysis. Instead, other factors, such as ECOG status and more importantly grade of disease, appeared to affect survival significantly as independent elements. Based on our recent experience with patients treated for renal cell carcinoma in the era of enhanced technology and improved survival, tumor grade and molecular markers may serve as useful adjuncts to TNM staging in guiding treatment and predicting survival outcomes.

Adult↗
PubMed2000

Renal cell carcinoma: prognostic significance of incidentally detected tumors.

PURPOSE: We determined the prognostic significance of incidentally discovered renal cell carcinoma in the era of increased incidental detection. MATERIALS AND METHODS: We reviewed the records of 633 consecutive patients who underwent radical or partial nephrectomy for renal cell carcinoma at our institution between 1987 and 1998. Patients were divided into those who were asymptomatic and tumor was diagnosed incidentally and those diagnosed after presenting with any of the classic symptoms of renal cell carcinoma or subsequent metastasis. All renal cell carcinoma lesions were assigned a stage and grade according to 1997 TNM criteria. All patients were followed postoperatively to assess survival rates, and monitor recurrence and metastasis. RESULTS: Of the 633 patients 95 (15%) were treated for incidentally discovered renal cell carcinoma and 538 (85%) presented with symptoms secondary to renal cell carcinoma at diagnosis. Patient age and sex distribution were similar in the 2 groups. Stage I lesions were observed in 62.1% of patients with incidental renal cell carcinoma and in 23% with symptomatic renal cell carcinoma. In contrast, stage IV lesions were present in 27.4% of patients with incidental versus 54% with symptomatic renal cell carcinoma. Thus, incidental lesions were of significantly lower stage than those causing symptoms (p <0.001). Similarly 15.8% of incidental but 42.4% of symptomatic lesions were grade 3 or 4 (p = 0.006). Patients were followed postoperatively for a mean of 47 months plus or minus 40 months. The 5-year cancer specific survival rate was significantly higher for incidental than for symptomatic tumors (85.3% versus 62.5%). Likewise, the local and distal recurrence rates were higher for symptomatic lesions. When adjusted for stage, no difference in survival was noted in the 2 groups for stages I to III disease and a minimally significant difference was noted for stage IV cancer. Multivariate analysis of stage and grade attributed the survival difference in stage IV disease to the significantly higher grade of symptomatic lesions. CONCLUSIONS: At presentation incidental tumors are of significantly lower stage and grade than tumors producing symptoms. Subsequently these clinically and histologically less aggressive lesions lead to better patient survival and decreased recurrence. Thus, the detection of renal cell carcinoma before symptom onset enables treatment of less aggressive tumors and provides a better prognosis for patients. Given these data efforts should be directed toward the development of a screening protocol to detect these lesions early, so that they may be prevented from progressing to the point when symptoms are apparent and prognosis becomes worse. In addition, the significant correlation of tumor grade with survival in our study further demonstrates the prognostic value of tumor grade and molecular markers for the future evaluation and treatment of renal cell carcinoma.

Carcinoma, Renal Cell↗