Citations

ABSTRACT The circumstances under which unintegrated lentivirus DNA can persist and be a functional template for transcription and protein expression are not clear. We constructed and validated the first class I (nonpleiotropic) integrase (IN) mutants for a non-human lentivirus (feline immunodeficiency virus [FIV]) and analyzed both these and known class I human immunodeficiency virus type 1 IN mutants. The FIV IN mutants (D66V and D66V/D118A) had class I properties: Gag/Pol precursor expression, proteolytic processing, particle formation, and reverse transcriptase (RT) production were normal, while the transduction of dividing fibroblasts was prevented and integration was blocked. When injected into rat retinas, the wild-type (WT) vector produced extensive, persistent transgene expression, compared with only rare positive neuronal cells for the IN mutant vector. In contrast, both WT and mutant vectors produced entirely equivalent, effective transduction levels of primary rat neurons (retinal ganglion cells). By testing the hypothesis that the unexpected retinal neuron transduction was related to cell cycle status, we found that when fibroblasts were growth arrested, transduction and internally promoted transgene expression were not inhibited at all by the class I FIV or HIV-1 IN mutations. Cells were then transduced under aphidicolin arrest and were released from the block 48 h later. Vector expression was stable and durable during repeated passaging in WT vector-transduced cells, while the release of cells transduced with equivalent RT units of class I IN mutant FIV or HIV vector resulted in a steady decline of expression, from 97 to 0% of cells by day 10. Southern blot and PCR analyses showed a lack of integration, irrespective of cell cycle, for the class I mutants and an increase in one- and two-long terminal repeat circular and linear unintegrated DNAs in growth-arrested cells. We conclude that if cell division is prevented, unintegrated FIV and HIV-1 vector DNAs can produce high-level internally promoted transgene expression equivalent to WT vectors. The expression correlates with the unintegrated DNA levels. These observations may facilitate the study of the roles of IN and other preintegration complex components in preintegration phases of infection by (i) providing an alternative way to monitor unintegrated nuclear cDNA forms, (ii) restricting ascertainment to the transcriptionally functional subset of unintegrated DNA, (iii) enabling analysis in individual, nondividing cells, and (iv) uncoupling other potential functions of IN from integration.

AbstractThe Edmonston vaccine strain of measles virus (MV-Edm) propagates efficiently in a broad range of human tumor cells, killing them selectively. However, the oncolytic potency of MV-Edm in different human tumor xenograft therapy models is highly variable and there is no convenient way to map the distribution of virus-infected tissues in vivo. To enhance the oncolytic potency of MV-Edm against radiosensitive malignancies and to facilitate noninvasive imaging of infected tissues, we generated a recombinant MV-Edm encoding the human thyroidal iodide symporter (NIS). MV-NIS replicated almost as efficiently as unmodified MV-Edm, and human tumor cells efficiently concentrated radioiodine when infected with MV-NIS. Intratumoral spread of MV-NIS was noninvasively demonstrated by serial gamma-camera imaging of iodine-123 (123I) uptake both in MV-sensitive KAS-6/1 myeloma xenografts, which regressed completely after a single intravenous dose of MV-NIS, and in MM1 myeloma xenografts, which were unresponsive to MVNIS therapy. However, MV-resistant MM1 tumors regressed completely when 131I was administered 9 days after a single intravenous injection of MV-NIS (radiovirotherapy). 131I alone had no effect on MM1 tumor growth. While the potential hematopoietic toxicity of this new therapy requires further evaluation, image-guided radiovirotherapy is a promising new approach to the treatment of multiple myeloma, an incurable but highly radiosensitive plasma cell malignancy. Testing in other radiosensitive cancers is warranted.

Purpose: To evaluate the antitumor activity, safety, immune response, and replication of CI-1042 (ONYX-015), an E1B 55-kd gene-deleted replication-selective adenovirus, administered intravenously to patients with metastatic colorectal cancer Patients and Methods: Eighteen patients with metastatic colorectal cancer for whom prior chemotherapy failed were enrolled onto an open-label, multicenter, phase II study. CI-1042 was administered intravenously at a dose of 2 × 1012 viral particles every 2 weeks. Patients were evaluated for tumor response and toxicity; in addition, blood samples were taken for adenovirus DNA and neutralizing antibody analysis. Results: Common toxicities included flu-like symptoms, nausea, and emesis. All 18 patients eventually were removed from study because of progressive disease. Seven patients were assessed as having stable disease after 2 months of treatment, whereas two patients were considered to have stable disease after 4 months. Detectable circulating CI-1042 DNA was identified in 36% of patients 72 hours after last infusion, which is suggestive of ongoing viral replication. Conclusion: In this phase II study, intravenous CI-1042 was administered safely to patients with advanced colorectal cancer. Toxicity was manageable, consisting primarily of flu-like symptoms. Stable disease was experienced by seven patients for 11 to 18 weeks.

Renal artery stenosis (RAS) may cause hypertension, azotemia, episodes of flash pulmonary edema and congestive heart failure. Renal artery angioplasty and stenting was performed in 207 patients from 1991 to 1997. Thirty-nine of these patients (19%) underwent renal artery stenting for the control of recurrent episodes of congestive heart failure and flash pulmonary edema. All patients had angiographic evidence of severe (>70%) bilateral RAS (n = 18) or severe RAS to a solitary functioning kidney (n = 21). Sixteen patients (41%) were male and 23 (59%) were female, mean age 69.9 years (range 50- 85 years). Of the 18 patients with bilateral RAS, 12 (66.6%) underwent bilateral stenting. Mean blood pressure decreased from 174/85 6 32/23 mmHg to 148/72 6 24/14 mmHg (p < 0.001). Mean number of blood pressure medications decreased from 3 6 1 to 2.5 6 1 (p = 0.006). Twenty-eight patients (71.8%) had improvement in blood pressure control. The mean serum creatinine decreased from 3.16 6 1.61 to 2.65 6 1.87 (p = 0.06). Six of 39 patients (15.4%) used angiotensin converting enzyme (ACE) inhibitors prior to stenting whereas 19 of 39 patients (48.7%) used ACE inhibitors poststenting (p = 0.004). Twenty of 39 patients (51.4%) demonstrated improvement in serum creatinine, 10 of 39 patients (25.6%) had stabilization of serum creatinine and nine of 39 patients (23%) demonstrated worsening. The number of hospitalizations due to congestive heart failure in the year preceding renal artery stenting was 2.4 6 1.4 and poststenting was 0.3 6 0.7 (p < 0.001). The New York Heart Association Functional Class decreased from 2.9 6 0.9 prestenting to 1.6 6 0.9 poststenting (p < 0.001). Thirty of 39 patients (77%) had no hospitalizations for congestive heart failure during a mean follow-up period of 21.3 months. Nine patients expired during the course of follow up; eight of the nine patients died within the first year after renal artery stenting. Renal artery stenting decreased the frequency of congestive heart failure, flash pulmonary edema, and the need for hospitalization in most patients. Blood pressure was markedly improved in the majority of patients with improved or stabilized renal function. Evaluation for RAS is important in hypertensive patients who present with recurrent congestive heart failure or flash pulmonary edema.

ABSTRACT Caveolin-1 (Cav-1) is a major protein constituent of caveolae, a type of plasma membrane raft. We observed that coexpression of human Cav-1 with human immunodeficiency virus type 1 (HIV-1) blocked virion production from cells that are ordinarily highly permissive. Further investigation showed that this effect is specific, occurs at low ratios of Cav-1 to HIV-1 DNA, depends on expression of Cav-1 protein, and involves severely impaired expression of HIV-1 proteins. Cav-1 also blocked HIV-2 expression. In contrast, Cav-1 did not inhibit protein expression by a paramyxovirus and did not induce apoptosis or affect cellular morphology, cell viability, or cell cycle progression. Although only small amounts of HIV-1 virions were released from Cav-1-transfected cells, these were fully infectious. Deletion mutagenesis showed that the C-terminal 78 residues were as active as the full-length (178-amino-acid) protein in producing the block. In contrast, the 100 most N-terminal amino acids of Cav-1, which include the previously identified oligomerization and scaffolding domains, were shown to be dispensable. Study of single-amino-acid-exchange mutants of Cav-1 established that palmitoylation was not required. Additional deletion mutants then identified the hydrophobic, membrane-associated domain (residues 101 to 135) as the main determinant. Cellular distribution of wild-type and mutant proteins correlated with ability to block HIV-1 expression. Finally, Cav-2 also blocked HIV-1 expression. These data show that coexpression of caveolins can markedly inhibit expression of HIV proviral DNA and establish that the inhibition is mediated by the hydrophobic, membrane-associated domain.