Clonal variation in interferon response determines the outcome of oncolytic virotherapy in mouse CT26 colon carcinoma model.

In our earlier studies, Semliki Forest virus vector VA7 completely eliminated type I interferon (IFN-I)-unresponsive human U87-luc glioma xenografts, whereas interferon-responsive mouse gliomas proved refractory. Here, we describe in two clones of CT26 murine colon carcinoma, opposed patterns of IFN-I responsiveness and sensitivity to VA7. Both CT26WT and CT26LacZ clones secreted biologically active interferon in vitro upon virus infection but only CT26WT cells were protected. Focal infection of CT26WT cultures was self-limiting but could be rescued using IFN-I pathway inhibitor Ruxolitinib or antibody against IFNß. Whole transcriptome sequencing (RNA-Seq) and protein expression analysis revealed that CT26WT cells constitutively expressed 56 different genes associated with pattern recognition and IFN-I signaling pathways, spanning two reported anti-RNA virus gene signatures and 22 genes with reported anti-alphaviral activity. Whereas CT26WT tumors were strictly virus-resistant in vivo, infection of CT26LacZ tumors resulted in complete tumor eradication in both immunocompetent and severe combined immune deficient mice. In double-flank transplantation experiments, CT26WT tumors grew despite successful eradication of CT26LacZ tumors from the contralateral flank. Tumor growth progressed uninhibited also when CT26LacZ inoculums contained only a small fraction of CT26WT cells, demonstrating dominance of IFN responsiveness when heterogeneous tumors are targeted with interferon-sensitive oncolytic viruses.

Robust envelope exchange platform for oncolytic measles virus.

The use of oncolytic viruses (OV) to precisely target and eliminate tumors ('virotherapy') is a rapidly evolving therapeutic approach to treating cancer. A major obstacle in virotherapy, especially for systemic administration, is the host's immune response towards the OV. In the case of measles virus (MeV), most individuals have been immunized against this agent leading to pre-existing neutralizing antibodies that can impair OV delivery to the tumor. These antibodies predominantly target the hemagglutinin (H) and fusion (F) envelope glycoproteins displayed at the particle's surface. Here, we introduce a novel and versatile pseudotyping platform for rapid envelope exchange of oncolytic MeV that allows for engineering of chimeric viruses invulnerable to pre-existing anti-MeV antibodies. Using this system, we have successfully exchanged the MeV F and H proteins with the glycoprotein G of vesicular stomatitis virus (VSV) and the surface proteins of Newcastle disease virus (NDV) or canine distemper virus (CDV), all of which are not endemic in the general human population. While the MeV-VSV and MeV-NDV pseudotypes were non-functional, the MeV-CDV pseudotype was successfully propagated to high-titer virus stocks. This study describes the successful generation of a robust envelope exchange platform for oncolytic MeV while also highlighting its intricate pseudotyping tolerance.

Enhanced killing of androgen-independent prostate cancer cells using inositol hexakisphosphate in combination with proteasome inhibitors.

Effective treatments for androgen-independent prostate cancer (AIPCa) are lacking. To address this, emerging therapeutics such as proteasome inhibitors are currently undergoing clinical trials. Inositol hexakisphosphate (IP6) is an orally non-toxic phytochemical that exhibits antitumour activity against several types of cancer including PCa. We have previously shown that treatment of PC3 cells with IP6 induces the transcription of a subset of nuclear factor-kappaB (NF-kappaB)-responsive and pro-apoptotic BCL-2 family genes. In this study, we report that although NF-kappaB subunits p50/p65 translocate to the nucleus of PC3 cells in response to IP6, inhibition of NF-kappaB-mediated transcription using non-degradable inhibitor of kappaB (IkappaB)-alpha does not modulate IP6 sensitivity. Treatment with IP6 also leads to increased protein levels of PUMA, BIK/NBK and NOXA between 4 and 8 h of treatment and decreased levels of MCL-1 and BCL-2 after 24 h. Although blocking transcription using actinomycin D does not modulate PC3 cell sensitivity to IP6, inhibition of protein translation using cycloheximide has a significant protective effect. In contrast, blocking proteasome-mediated protein degradation using MG-132 significantly enhances the ability of IP6 to reduce cellular metabolic activity in both PC3 and DU145 AIPCa cell lines. This effect of combined treatment on mitochondrial depolarisation is particularly striking and is also reproduced by another proteasome inhibitor (ALLN). The enhanced effect of combined MG132/IP6 treatment is almost completely inhibited by cycloheximide and correlates with changes in BCL-2 family protein levels. Altogether these results suggest a role for BCL-2 family proteins in mediating the combined effect of IP6 and proteasome inhibitors and warrant further pre-clinical studies for the treatment of AIPCa.

A double-blind comparison of the efficacy and safety of ivermectin and diethylcarbamazine in a placebo controlled study of Senegalese patients with onchocerciasis.

Ivermectin (MK-933) has been compared with diethylcarbamazine (DEC) and placebo in a double-blind study in 30 adult male Senegalese patients with Onchocerca volvulus infection. 10 patients were randomly assigned to each treatment group. Ivermectin was administered as a single oral dose of 12 mg and DEC as 50 mg daily for two days and 100 mg twice daily for the following six days, total 1.3 g in eight days. Skin O. volvulus microfilaria densities remained near pre-study values in the placebo patients, but decreased rapidly with both active drugs to mean values about 2% of pretreatment (Day 8) and then increased slowly, reaching in 12 months about 4% of pre-treatment (ivermectin) and 18% (DEC). This difference is statistically significant. Clinical adverse reactions were recorded in four ivermectin, ten DEC and three placebo patients. One ivermectin and six DEC patients received steroid treatment for relief of these reactions. Serious adverse ocular changes were not seen in any patients, possibly because of the steroid therapy in the DEC patients. Adult O. volvulus from onchocercal nodules one and six months after treatment showed no effect of either drug on viability. Intra-uterine developing forms of the microfilariae appeared normal in all three treatment groups at the one month examination but deformed and degenerated forms were evident at six months in the ivermectin group but not in the DEC and placebo patients. Ivermectin as a single oral dose appears to be a safer and more effective microfilaricidal drug in human onchocerciasis than DEC in the standard multi-dose regimen.