MV-NIS is an engineered measles virus that is selectively destructive to myeloma plasma cells and can be monitored by noninvasive radioiodine imaging of NIS gene expression. Two measles-seronegative patients with relapsing drug-refractory myeloma and multiple glucose-avid plasmacytomas were treated by intravenous infusion of 1011 TCID50 (50% tissue culture infectious dose) infectious units of MV-NIS. Both patients responded to therapy with M protein reduction and resolution of bone marrow plasmacytosis. Further, one patient experienced durable complete remission at all disease sites. Tumor targeting was clearly documented by NIS-mediated radioiodine uptake in virus-infected plasmacytomas. Toxicities resolved within the first week after therapy. Oncolytic viruses offer a promising new modality for the targeted infection and destruction of disseminated cancer.

The global transcriptional coactivators CREB-binding protein (CBP) and the closely related p300 interact with over 312 proteins, making them among the most heavily connected hubs in the known mammalian protein-protein interactome. It is largely uncertain, however, if these interactions are important in specific cell lineages of adult animals, as homozygous null mutations in either CBP or p300 result in early embryonic lethality in mice. Here we describe a Cre/LoxP conditional p300 null allele (p300 flox ) that allows for the temporal and tissue-specific inactivation of p300. We used mice carrying p300 flox and a CBP conditional knockout allele (CBP flox ) in conjunction with an Lck-Cre transgene to delete CBP and p300 starting at the CD4 ؊ CD8 ؊ double-negative thymocyte stage of T-cell development. Loss of either p300 or CBP led to a decrease in CD4 ؉ CD8 ؉ double-positive thymocytes, but an increase in the percentage of CD8 ؉ single-positive thymocytes seen in CBP mutant mice was not observed in p300 mutants. T cells completely lacking both CBP and p300 did not develop normally and were nonexistent or very rare in the periphery, however. T cells lacking CBP or p300 had reduced tumor necrosis factor alpha gene expression in response to phorbol ester and ionophore, while signal-responsive gene expression in CBP-or p300-deficient macrophages was largely intact. Thus, CBP and p300 each supply a surprising degree of redundant coactivation capacity in T cells and macrophages, although each gene has also unique properties in thymocyte development.

CBP can function as a tumor suppressor, but the mechanisms that govern oncogenesis in its absence are unknown. Here we show that CBP inactivation in mouse thymocytes leads to lymphoma. Although CBP has been implicated in the transactivation functions of p53, development of these tumors does not seem to involve loss of p53 activity. CBP-null tumors show reduced levels of p27Kip1 and increased levels of cyclin E and Skp2, two oncoproteins that can promote p27Kip1 proteolysis. Reduction of p27Kip1 by introduction of a p27Kip1-null allele into CBP knockout mice accelerates lymphomagenesis and seems to obviate the requirement for Skp2 and cyclin E upregulation. These data suggest that CBP loss mediates lymphomagenesis in cooperation with a mechanism that reduces p27Kip1 abundance.

MV-NIS is an Edmonston-lineage oncolytic measles virus expressing the human sodium-iodide symporter--a means for monitoring by noninvasive imaging of radioiodine. Patients with relapsed, refractory myeloma who had explored all other treatment options were eligible for this Phase I trial. Cohort 1 was treated with intravenous MV-NIS, and Cohort 2 received cyclophosphamide two days prior to MV-NIS. Thirty-two patients were treated. Cohort 1 initially enrolled to 4 dose-levels without reaching MTD and subsequently to 2 higher dose-levels when improved virus manufacture technology made it possible. MTD was not reached in Cohort 1, and TCID50 1011 is the dose being used in a Phase II trial of single agent MV-NIS. Grade 3–4 AEs in both cohorts at all dose levels were: neutropenia (n=9); leukocyte count decreased (n=5); thrombocytopenia (n=2); and CD4 lymphocytes decreased, anemia and lymphopenia (each n=1). MV-N RNA sequences were amplified from gargle specimens, blood and urine. 123I scans were positive in 8 patients. One patient achieved a CR; transient drops in serum FLCs were seen in other patients. MV-NIS is capable of replicating before being cleared by the immune system. Oncolytic viruses offer a promising new modality for the targeted infection and destruction of disseminated myeloma.

Oncolytic measles virus (MV) induces cell fusion and cytotoxicity in a CD46-dependent manner. Development of fully retargeted oncolytic MVs would improve tumor selectivity. The urokinase-type plasminogen activator receptor (uPAR) is a tumor and stromal target overexpressed in multiple malignancies. MV-H glycoproteins fully retargeted to either human or murine uPAR were engineered and their fusogenic activity was determined. Recombinant human (MV-h-uPA) and murine (MV-m-uPA) uPAR-retargeted MVs expressing enhanced green fluorescent protein (eGFP) were rescued and characterized. Viral expression of chimeric MV-H was shown by reverse transcription-PCR and Western blot. In vitro viral replication was comparable to MV-GFP control. The receptor and species specificity of MV-uPAs was shown in human and murine cells with different levels of uPAR expression. Removal of the NH 2 -terminal fragment ligand from MV-uPA by factor X(a) treatment ablated the MV-uPA functional activity. Cytotoxicity was shown in uPAR-expressing human and murine cells. MV-h-uPA efficiently infected human endothelial cells and capillary tubes in vitro. I.v. administration of MV-huPA delayed tumor growth and prolonged survival in the MDA-MB-231 breast cancer xenograft model. Viral tumor targeting was confirmed by immunohistochemistry. MV-muPA transduced murine mammary tumors (4T1) in vivo after intratumor administration. MV-m-uPA targeted murine tumor vasculature after systemic administration, as shown by dual (CD31 and MV-N) staining of tumor capillaries in the MDA-MB-231 model. In conclusion, MV-uPA is a novel oncolytic MV associated with potent and specific antitumor effects and tumor vascular targeting. This is the first retargeted oncolytic MV able to replicate in murine cells and target tumor vasculature in a uPAR-dependent manner.

Off target binding or vector sequestration can significantly limit the efficiency of systemic virotherapy. We report here that systemically administered oncolytic measles virus (MV) was rapidly sequestered by the mononuclear phagocytic system (MPS) of the liver and spleen in measles receptor CD46-positive and CD46-negative mice. Since scavenger receptors on Kupffer cells are responsible for the elimination of blood-borne pathogens, we investigated here if MV uptake was mediated by scavenger receptors on Kupffer cells. Pretreatment of cells with poly(I), a scavenger receptor ligand, reduced MV expression by 99% in murine (J774A.1) macrophages and by 50% in human (THP-1) macrophages. Pre-dosing of mice with poly(I) reduced MPS sequestration of MV and increased circulating levels of MV by 4 to 15-folds at 2 minutes post virus administration. Circulating virus was still detectable 30 mins post infusion in mice predosed with poly(I) while no detectable MV was found at 5–10 min post infusion if mice did not receive poly(I). MPS blockade by poly(I) enhanced virus delivery to human ovarian SKOV3ip.1 and myeloma KAS6/1 xenografts in mice. Higher gene expression and improved control of tumor growth was noted early post therapy. Based on these results, incorporation of MPS blockade into MV treatment regimens is warranted.

In this mouse model, uPA expression delayed tumor progression and had antiangiogenic and antiproliferative effects that may be mediated by uPA's protease activity. These results challenge the current dogma of proteases being exclusively tumor promoting and provide further rationale for exploring plasminogen activators as antitumor agents.

The present study demonstrates that cyclin D1 can be used as an indicator of recurrence and subsequent prognosis in nasopharyngeal carcinoma after radiation therapy. At the same time, the apoptotic state before radiation therapy is of no value in predicting the prognosis of patients with nasopharyngeal carcinoma.