Russell, Stephen J.

The Sleeping Beauty (SB) transposon system has been shown to mediate new gene sequence integration resulting in long-term expression. Here the effectiveness of hyperactive SB100X transposase was tested, and we found that hydrodynamic co-delivery of a firefly luciferase transposon (pT2/CaL) along with SB100X transposase (pCMV-SB100X) resulted in remarkably sustained, high levels of luciferase expression. However, after 4 weeks there was a rapid, animal-by-animal loss of luciferase expression that was not observed in immunodeficient mice. We hypothesized that this sustained, high-level luciferase expression achieved using the SB100X transposase elicits an immune response in pT2/CaL co-administered mice, which was supported by the rapid loss of luciferase expression upon challenge of previously treated animals and in naive animals adoptively transferred with splenocytes from previously treated animals. Specificity of the immune response to luciferase was demonstrated by increased cytokine expression in splenocytes after exposure to luciferase peptide in parallel with MHC I–luciferase peptide tetramer binding. This anti-luciferase immune response observed following continuous, high-level luciferase expression in vivo clearly impacts its use as an in vivo reporter. As both an immunogen and an extremely sensitive reporter, luciferase is also a useful model system for the study of immune responses following in vivo gene transfer and expression.

ABSTRACT VSV-FH is a hybrid vesicular stomatitis virus (VSV) with a deletion of its G glycoprotein and encoding the measles virus (MV) fusion (F) and hemagglutinin (H) envelope glycoproteins. VSV-FH infects cells expressing MV receptors and is fusogenic and effective against myeloma xenografts in mice. We evaluated the fusogenic activities of MV and VSV-FH in relationship to the density of receptor on the target cell surface and the kinetics of F and H expression in infected cells. Using a panel of cells expressing increasing numbers of the MV receptor CD46, we evaluated syncytium size in MV- or VSV-FH-infected cells. VSV-FH is not fusogenic at low CD46 density but requires less CD46 for syncytium formation than MV. The size of each syncytium is larger in VSV-FH-infected cells at a specific CD46 density. While syncytium size reached a plateau and did not increase further in MV-infected CHO cells expressing ≥4,620 CD46 copies/cell, there was a corresponding increase in syncytium size with increases in CD46 levels in VSV-FH-infected CD46-expressing CHO (CHO-CD46) cells. Further analysis in VSV-FH-infected cell lines shows earlier and higher expression of F and H mRNAs and protein. However, VSV-FH cytotoxic activity was reduced by pretreatment of the cells with type I interferon. In contrast, the cytopathic effects are not affected in MV-infected cells. In summary, VSV-FH has significant advantages over MV as an oncolytic virus due to its higher viral yield, faster replication kinetics, and larger fusogenic capabilities but should be used in cancer types with defective interferon signaling pathways. IMPORTANCE We studied the cytotoxic activity of a vesicular stomatitis/measles hybrid virus (VSV-FH), which is superior to that of measles virus (MV), in different cancer cell lines. We determined that viral RNA and protein were produced faster and in higher quantities in VSV-FH-infected cells. This resulted in the formation of larger syncytia, higher production of infectious particles, and a more potent cytopathic effect in permissive cells. Importantly, VSV-FH, similar to MV, can discriminate between low- and high-expressing CD46 cells, a phenotype important for cancer therapy as the virus will be able to preferentially infect cancer cells that overexpress CD46 over low-CD46-expressing normal cells.

ABSTRACT Because of its very low human seroprevalence, vesicular stomatitis virus (VSV) has promise as a systemic oncolytic agent for human cancer therapy. However, as demonstrated in this report, the VSV infectious titer drops by 4 log units during the first hour of exposure to nonimmune human serum. This neutralization occurs relatively slowly and is mediated by the concerted actions of natural IgM and complement. Maraba virus, whose G protein is about 80% homologous to that of VSV, is relatively resistant to the neutralizing activity of nonimmune human serum. We therefore constructed and rescued a recombinant VSV whose G gene was replaced by the corresponding gene from Maraba virus. Comparison of the parental VSV and VSV with Maraba G substituted revealed nearly identical host range properties and replication kinetics on a panel of tumor cell lines. Moreover, in contrast to the parental VSV, the VSV with Maraba G substituted was resistant to nonimmune human serum. Overall, our data suggest that VSV with Maraba G substituted should be further investigated as a candidate for human systemic oncolytic virotherapy applications. IMPORTANCE Oncolytic virotherapy is a promising approach for the treatment of disseminated cancers, but antibody neutralization of circulating oncolytic virus particles remains a formidable barrier. In this work, we developed a pseudotyped vesicular stomatitis virus (VSV) with a glycoprotein of Maraba virus, a closely related but serologically distinct member of the family Rhabdoviridae , which demonstrated greatly diminished susceptibility to both nonimmune and VSV-immune serum neutralization. VSV with Maraba G substituted or lentiviral vectors should therefore be further investigated as candidates for human systemic oncolytic virotherapy and gene therapy applications.

AbstractImmunoglobulin light chain (AL) Amyloidosis is a condition whereby misfolded proteins generated by plasma cells deposit in tissues causing organ dysfunction. Chemotherapy and autologous stem cell transplant when eligible are standard treatment options. Several studies report long‐term outcomes of patients post‐transplant. However, there is a paucity of literature describing outcomes of relapsed patients post‐transplant. We performed a retrospective study to assess outcomes and therapies employed upon relapse after transplant. Between 1996 and 2009, 410 patients received transplant at the Mayo Clinic as first‐line therapy. Of those patients, 42 (10%) died within 3 months of transplant, 64 (16%) died without documented relapse, 158 (38%) were alive without documented progression, and 146 (36%) had documented progression. Those 146 patients are the subject of our study, and their median time to hematologic relapse/progression was 23.6 months (95%CI 18.3, 26.3 months). Their median overall survival and 5‐yrs overall survival from post‐transplant relapse/progression was 51.7 months (95%CI 34.1–62.3) and 39%, respectively. The most common first regimen for treatment after relapse was lenalidomide or thalidomide. In conclusion, our study indicates that patients with AL amyloidosis fare well post‐transplant relapse/progression. Additionally, it provides a yardstick to design clinical trials to determine best treatment options.

Objectives To define whether the high sensitivity cardiac troponin T (hs-cTnT) assay in patients with immunoglobulin light chain amyloidosis (AL) improves risk prediction. Background Cardiac involvement is the major cause of death in patients with AL amyloidosis. Risk stratification is facilitated by cardiac biomarkers such as cardiac troponin T (cTnT) and N-terminal pro B-type natriuretic peptide (NT-proBNP). Methods Stored serum from patients with newly diagnosed AL was used to measure hs-cTnT, cTnT, and NT-proBNP. Survival modelling was performed. Results The direct numeric result from hs-cTnT measurement cannot merely be substituted for a cTnT measurement in the Mayo AL staging system. The performance of the receiver operator curve derived an hs-cTnT cut-point of 54 ng/L which improves on the value of 35 ng/L validated with the prior iteration of the assay. An alternate staging option using hs-cTnT alone—using the two thresholds 14 ng/L and 54 ng/L—performs as well as either the original Mayo AL staging system or other systems incorporating hs-cTnT. On multivariate analysis, an hs-cTnT alone staging system was independent of period of diagnosis, type of therapy, and NT-proBNP value, the last of which dropped out of the model. Alternate models were explored, but none performed better than the original system or the new hs-cTnT system. Thus, hs-cTnT can be used alone for the staging of disease prognosis. Conclusions A survival model based on hs-cTnT improves the prognostic staging of patients with AL amyloidosis, relegating NT-proBNP to a measure of cardiac response.

ABSTRACT Measles virus (MV) immunosuppression is due to infection of SLAM-positive immune cells, whereas respiratory shedding and virus transmission are due to infection of nectin4-positive airway epithelial cells. The vaccine lineage MV strain Edmonston (MV-Edm) acquired an additional tropism for CD46 which is the basis of its oncolytic specificity. VSVFH is a vesicular stomatitis virus (VSV) encoding the MV-Edm F and H entry proteins in place of G. The virus spreads faster than MV-Edm and is highly fusogenic and a potent oncolytic. To determine whether ablating nectin4 tropism from VSVFH might prevent shedding, increasing its safety profile as an oncolytic, or might have any effect on CD46 binding, we generated VSVFH viruses with H mutations that disrupt attachment to SLAM and/or nectin4. Disruption of nectin4 binding reduced release of VSVFH from the basolateral side of differentiated airway epithelia composed of Calu-3 cells. However, because nectin4 and CD46 have substantially overlapping receptor binding surfaces on H, disruption of nectin4 binding compromised CD46 binding and greatly diminished the oncolytic potency of these viruses on human cancer cells. Thus, our results support continued preclinical development of VSVFH without ablation of nectin4 binding.

There are no systematic data regarding nonmaintained induction for those patients with multiple myeloma (MM) who do not receive consolidative autologous stem cell transplantation. Of 173 patients with newly diagnosed MM treated with lenalidomide and dexamethasone (LenDex) as primary therapy, 31 patients had their lenalidomide discontinued for reasons other than progression or alternate therapy. Median progression free survival (PFS) from the time of discontinuing lenalidomide was longer in patients who received lenalidomide ≥1 year (39 vs. 13 months, P < 0.05); there was no difference in PFS for those treated for 1–2 years as compared to ≥2 years. Among those taking lenalidomide for ≥1 year PFS was superior in patients who were in very good partial response (VGPR) or better as compared to those with partial response (48.4 versus 14.8 months, P < 0.05). All patients who progressed and were rechallenged with LenDex responded. These analyses illustrate that discontinuation of lenalidomide after 1 year among those patients achieving a ≥VGPR can result in long‐term disease control. Am. J. Hematol. 89:302–305, 2014. © 2013 Wiley Periodicals, Inc.

Purpose To study the impact of achieving stringent complete response (sCR), an increasingly attainable goal, after autologous stem-cell transplantation (ASCT) in patients with multiple myeloma (MM). Patients and Methods Maximal response rates were determined in 445 consecutive patients who underwent ASCT within 12 months of diagnosis of MM. The patients achieving varying degrees of complete response (CR) are the focus of our study. Results One hundred and nine patients (25%) achieved sCR after ASCT. The median overall survival (OS) rate from the time of transplantation for patients attaining sCR was not reached (NR), in contrast to those patients achieving conventional complete response (CR; n = 37; OS, 81 months) or near CR (nCR; n = 91; OS, 60 months; P < .001). Five-year OS rates were 80%, 53%, and 47% for sCR, CR, and nCR, respectively. The median time to progression (TTP) from ASCT of patients achieving sCR was significantly longer (50 months) than TTP of patients achieving CR or nCR (20 months and 19 months, respectively). On multivariable analysis, post-ASCT response of sCR was an independent prognostic factor for survival (hazard ratio, 0.44; 95% CI, 0.25 to 0.80; versus CR; P = .008), in addition to proliferation rate, pre-ASCT cytogenetics, and performance status. OS rates of patients attaining sCR continued to remain superior at 2-year landmark (median, NR v 70 months for conventional CR group; P = .007). Conclusion Improved long-term outcome is seen after ASCT with achievement of sCR when compared with lesser degrees of responses. Myeloma trials reporting the response rates should identify patients achieving sCR and CR separately, owing to markedly disparate outcomes of the two categories.

Purpose There is consensus that patients with light chain (AL) amyloidosis with hypercalcemia, renal failure, anemia, and lytic bone lesions attributable to clonal expansion of plasma cells (CRAB criteria) also have multiple myeloma (MM). The aim of this study was to examine the spectrum of immunoglobulin AL amyloidosis with and without MM, with a goal of defining the optimal bone marrow plasma cell (BMPC) number to qualify as AL amyloidosis with MM. Patients and Methods We identified 1,255 patients with AL amyloidosis seen within 90 days of diagnosis between January 1, 2000, and December 31, 2010. We defined a population of patients with coexisting MM on the basis of the existence of CRAB criteria (AL-CRAB). Receiver operating characteristic analysis determined the optimal BMPC cut point to predict for 1-year mortality in patients with AL amyloidosis without CRAB to produce two additional groups: AL only (≤ 10% BMPCs) and AL plasma cell MM (AL-PCMM; > 10% BMPCs). Results Among the 1,255 patients, 100 (8%) had AL-CRAB, 476 (38%) had AL-PCMM, and 679 (54%) had AL only. Their respective median overall survival rates were 10.6, 16.2, and 46 months (P < .001). Because the outcomes of AL-CRAB and AL-PCMM were similar, they were pooled for univariate and multivariate analyses. On multivariate analysis, pooled AL-CRAB and AL-PCMM retained negative prognostic value independent of age, Mayo Clinic AL amyloidosis stage, prior autologous stem-cell transplantation, and difference between the involved and uninvolved free light chain. Conclusion Patients with AL amyloidosis who have more than 10% BMPCs have a poor prognosis, similar to that of patients with AL-CRAB, and should therefore be considered together as AL amyloidosis with MM.