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A S Belldegrun

Publications and source records attributed to A S Belldegrun.

40 records · Page 3Linked to original sources
PubMed1992

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.

Base Sequence↗
PubMed1992

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.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Actinomycin D and gemcitabine synergistically sensitize androgen-independent prostate cancer cells to Apo2L/TRAIL-mediated apoptosis.

The cytotoxic efficacy and kinetics involved in sensitization of Apo2L/TRAIL-resistant, androgen-independent prostate cancer cells to Apo2L/TRAIL or tumor necrosis factor-alpha or Fas ligand-mediated apoptosis were tested using subclinical concentrations of actinomycin D, paclitaxel, cisplatinum, gemcitabine, and radiation in CL-1, LNCaP, DU-145, and PC3 prostate cancer cell lines. CL-1 cells expressed all four Apo2L/TRAIL receptors and were resistant to Apo2L/TRAIL-mediated apoptosis (1-5,000 ng/mL) and to the sensitizers when given alone. Pretreatment with actinomycin D followed by Apo2L/TRAIL or tumor necrosis factor-alpha or anti-Fas CH-11 monoclonal antibody, but not in the reverse order, induced apoptosis in all cell lines. Synergistic sensitization in CL-1 cells was shown also with gemcitabine but not with cisplatinum, VP-16, paclitaxel, or radiation. Incubating the Apo2L/TRAIL-resistant CL-1, LNCaP, DU-145, and PC3 cell lines with 100 ng/mL actinomycin D for 4 hours followed by Apo2L/TRAIL for 24 hours resulted in 45.4 +/- 10.3%, 58.8 +/- 3.6%, 53.4 +/- 1.4%, and 84.2 +/- 8.4% apoptosis, respectively. Prolonging the sensitization time to 24 hours followed by 20 hours of incubation with Apo2L/TRAIL further enhanced the killing activity against CL-1 cells to 89 +/- 1% (delta = 60%, synergistic ratio = 3.1). This killing has a biphasic pattern that was contributed to by apoptosis (83%) and necrosis (17%) at 10 hours (peak) and 40% and 60%, respectively, at 20 hours. These results suggest that prostate cancer cells' resistance to Apo2L/TRAIL-mediated apoptosis can be reversed and synergy is achieved by sensitization of tumor cells with subclinical concentrations of actinomycin D or gemcitabine and may be useful clinically for the treatment of metastatic hormone- and drug-refractory prostate cancer.

Androgens↗