Project description:This study determined the patterns of gene expression of Clostridium novyi-NT in different growth phases in vitro as well as gene expression patterns from infection of tumors in vivo. Keywords: Growth phase analysis; tumor infection
Project description:The attenuated anaerobic bacterium Clostridium novyi-NT (C. novyi-NT) is known for its ability to precisely germinate in and eradicate treatment-resistant hypoxic tumors in various experimental animal models and spontaneously occurring canine sarcomas. In this article, we review the therapeutic and toxicologic aspects of C. novyi-NT therapy, key challenges and limitations, and promising strategies to optimize its performance via recombinant DNA technology and immunotherapeutic approaches, to establish C. novyi-NT as an essential tool in cancer therapy.
Project description:Species of Clostridium bacteria are notable for their ability to lyse tumor cells growing in hypoxic environments. We show that an attenuated strain of Clostridium novyi (C. novyi-NT) induces a microscopically precise, tumor-localized response in a rat orthotopic brain tumor model after intratumoral injection. It is well known, however, that experimental models often do not reliably predict the responses of human patients to therapeutic agents. We therefore used naturally occurring canine tumors as a translational bridge to human trials. Canine tumors are more like those of humans because they occur in animals with heterogeneous genetic backgrounds, are of host origin, and are due to spontaneous rather than engineered mutations. We found that intratumoral injection of C. novyi-NT spores was well tolerated in companion dogs bearing spontaneous solid tumors, with the most common toxicities being the expected symptoms associated with bacterial infections. Objective responses were observed in 6 of 16 dogs (37.5%), with three complete and three partial responses. On the basis of these encouraging results, we treated a human patient who had an advanced leiomyosarcoma with an intratumoral injection of C. novyi-NT spores. This treatment reduced the tumor within and surrounding the bone. Together, these results show that C. novyi-NT can precisely eradicate neoplastic tissues and suggest that further clinical trials of this agent in selected patients are warranted.
Project description:Bacteriolytic anti-cancer therapies employ attenuated bacterial strains that selectively proliferate within tumors. Clostridium novyi-NT spores represent one of the most promising of these agents, as they generate potent anti-tumor effects in experimental animals. We have determined the 2.55-Mb genomic sequence of C. novyi-NT, identifying a new type of transposition and 139 genes that do not have homologs in other bacteria. The genomic sequence was used to facilitate the detection of transcripts expressed at various stages of the life cycle of this bacterium in vitro as well as in infections of tumors in vivo. Through this analysis, we found that C. novyi-NT spores contained mRNA and that the spore transcripts were distinct from those in vegetative forms of the bacterium.
Project description:Branched gold nanoparticle (BGNP)-coated Clostridium novyi-NT (C. novyi-NT) spores are developed for computed tomography (CT)-guided bacteriolytic tumor therapy. The BGNP-coated spores are successfully injected into a tumor site under CT image guidance. As a result, a strong antitumor effect is observed in a PC3 prostate tumor-bearing mouse model.
Project description:BackgroundHypoxia is a prominent feature of solid tumors and can function as fertile environment for oncolytic anaerobic bacteria such as Clostridium novyi-NT (C. novyi-NT) where it can induce tumor destruction in mice and patients. However, two major obstacles have limited its use, namely the host inflammatory response and the incomplete clearance of normoxic tumor areas.MethodsIn this study, we first used a subcutaneous tumor model of a glioblastoma (GBM) cell line in immunocompetent mice to investigate the local distribution of tumor hypoxia, kinetics of C. novyi-NT germination and spread, and the local host immune response. We subsequently applied the acquired knowledge to develop a C. novyi-NT therapy in an orthotopic rabbit brain tumor model.ResultsWe found that local accumulation of granular leukocytes, mainly neutrophils, could impede the spread of bacteria through the tumor and prevent complete oncolysis. Depletion of neutrophils via anti-Ly6G antibody or bone marrow suppression using hydroxyurea significantly improved tumor clearance. We then applied this approach to rabbits implanted with an aggressive intracranial brain tumor and achieved long-term survival in majority of the animals without apparent toxicity.ConclusionThese results indicated that depleting neutrophils can greatly enhance the safety and efficacy of C. novyi-NT cancer therapy for brain tumors.
Project description:ObjectivesTo validate the feasibility of labeling Clostridium novyi-NT (C.novyi-NT) anaerobes with iron-oxide nanoparticles for magnetic resonance imaging (MRI) and demonstrate the potential to use MRI to visualize intra-tumoral delivery of these iron-oxide labeled C.novyi-NT during percutaneous injection procedures.Materials and methodsAll studies were approved by IACUC. C.novyi-NT were labeled with hybrid iron-oxide Texas red nanoparticles. Growth of labeled and control samples were evaluated with optical density. Labeling was confirmed with confocal fluorescence and transmission electron microscopy (TEM). MRI were performed using a 7 Tesla scanner with T2*-weighted (T2*W) sequence. Contrast-to-noise ratio (CNR) measurements were performed for phantoms and signal-to-noise ratio (SNR) measurements performed in C57BL/6 mice (n = 12) with Panc02 xenografts before and after percutaneous injection of iron-oxide labeled C.novyi-NT. MRI was repeated 3 and 7 days post-injection. Hematoxylin-eosin (HE), Prussian blue and Gram staining of tumor specimens were performed for confirmation of intra-tumoral delivery.ResultsIron-oxide labeling had no influence upon C.novyi-NT growth. The signal intensity (SI) within T2*W images was significantly decreased for iron-oxide labeled C.novyi-NT phantoms compared to unlabeled controls. Under confocal fluorescence microscopy, the iron-oxide labeled C.novyi-NT exhibited a uniform red fluorescence consistent with observed regions of DAPI staining and overall labeling efficiency was 100% (all DAPI stained C.novyi-NT exhibited red fluorescence). Within TEM images, a large number iron granules were observed within the iron-oxide labeled C.novyi-NT; these were not observed within unlabeled controls. Intra-procedural MRI measurements permitted in vivo visualization of the intra-tumoral distribution of iron-oxide labeled C.novyi-NT following percutaneous injection (depicted as punctate regions of SI reductions within T2*-weighted images); tumor SNR decreased significantly following intra-tumoral injection of C.novyi-NT (p<0.05); these SNR reductions were maintained at 3 and 7 day follow-up intervals. Prussian blue and Gram staining confirmed presence of the iron-oxide labeled anaerobes.ConclusionsC.novyi-NT can be labeled with iron-oxide nanoparticles for MRI visualization of intra-tumoral deposition following percutaneous injection during bacteriolytic therapy.
Project description:Although Clostridium novyi-NT is an anti-cancer bacterial therapeutic which germinates within hypoxic tumors to kill cancer cells, the actual germination triggers for C. novyi-NT are still unknown. In this study, we screen candidate germinants using combinatorial experimental designs and discover by serendipity that D-valine is a potent germinant, inducing 50% spore germination at 4.2 mM concentration. Further investigation revealed that five D-valine analogs are also germinants and four of these analogs are enantiomeric pairs. This stereoflexible effect of L- and D-amino acids shows that spore germination is a complex process where enantiomeric interactions can be confounders. This study also identifies L-cysteine as a germinant, and hypoxanthine and inosine as co-germinants. Several other amino acids promote (L-valine, L-histidine, L-threonine and L-alanine) or inhibit (L-arginine, L-glycine, L-lysine, L-tryptophan) germination in an interaction-dependent manner. D-alanine inhibits all germination, even in complex growth media. This work lays the foundation for improving the germination efficacy of C. novyi-NT spores in tumors.
Project description:A study of the polar lipids of Clostridium novyi NT has revealed the presence of phosphatidylethanolamine (PE) and cardiolipin as major phospholipids with smaller amounts of phosphatidylglycerol (PG), lysyl-PG and alanyl-PG. Other minor phospholipids included phosphatidic acid, CDP-diacylglycerol, phosphatidylserine (PS) and phosphatidylthreonine (PT). PE, PG and amino acyl PG were present in both the diacyl and alk-1'-enyl acyl (plasmalogen) forms and cardiolipin plasmalogens were found to contain one or two alk-1'-enyl chains. In contrast, the precursor lipids phosphatidic acid, CDP-diacylglycerol and PS were present almost exclusively as diacyl phospholipids. These findings are consistent with the hypothesis that plasmalogens are formed from diacylated phospholipids at a late stage of phospholipid formation in Clostridium species. This novel pathway contrasts with the route in animals in which a saturated ether bond is formed at an early stage of plasmalogen biosynthesis and the alk-1-enyl bond is formed by an aerobic mechanism.