This project uses genetic, biochemical and structural approaches to understand how autonomously replicating parvoviruses target and enter their host cells and establish infection. It will provide new information on the control of tissue tropis and on structural transitions in the virion that regulate successive steps in the infectious entry pathway of these ubiquitous viruses, particularly relating to an unexpected mode of genome exposure that could allow the capsid to fulfill novel intranuclear functions. The autonomously replicating parvoviruses are rugged and genetically simple single-stranded DNA viruses that are non-transforming because they are unable to activate resting cells to re-enter the cell cycle, and thus depend upon the host cell's regulation of cell cycle progression. In addition, many parvovirus species that infect rodents are inherently oncoselective, and preferentially infect transformed human cells, suggesting that they could be developed as therapeutic agents to target human tumors such as melanoma. The project pursues four approaches to understanding and exploiting such target specificity. 1. The targeting functions of the parvoviral shell will be identified by mapping the fortuitous tropism of parvovirus LuIII for human melanoma cells. This will involve making capsid chimeras with the non- melanotropic murine virus. Since LuIII is unlikely to be optimally melanotropic, we will use DNA shuffling to ask whether this property can be enhanced. 2. Differential qPCR analysis of sub-fractions of infected cells, expression of dominant-negative host genes and a novel in situ hybridization approach will be used to follow virions as they hijack specific intracellular trafficking pathways to gain access to the host nucleus. 3. Collaborative structural studies will be combined with genetic and biochemical approaches to investigate sequential conformational changes in the virion that facilitate ordered progress through its lifecycle. We have shown that genome uncoating is not a simple reversal of the packaging process, and will use these combined approaches to determine how the structurally symmetrical parvoviral capsid packages, retains and then releases its genome in the appropriate cellular compartments. 4. Optimized capsids will be used to package vectors designed to deliver heterologous genes into human and mouse melanoma cells. We will test the efficacy of a parvoviral vector packaged in an appropriately optimized capsid for targeting a transplantable murine melanoma in vivo. The vector expresses the B7-1 co-stimulatory molecule, and will potentially activate cytotoxic killer T-cells specific for melanoma tumor antigens, resulting in tumor eradication.
Advanced melanomas are stubbornly resistant to current therapeutic strategies, exhibit an aggressive clinical course and commonly give rise to late metastases. Despite recent advances in understanding the molecular basis of this cancer, new therapy options are urgently needed. The proposed studies are directed toward the understanding, development and use of parvoviral vectors designed to enhance the immunogenicity of melanoma cells, while providing important insight into fundamental mechanisms governing the establishment of parvoviral infection.
|Pittman, Nikéa; Misseldine, Adam; Geilen, Lorena et al. (2017) Atomic Resolution Structure of the Oncolytic Parvovirus LuIII by Electron Microscopy and 3D Image Reconstruction. Viruses 9:|
|Subramanian, Suriyasri; Organtini, Lindsey J; Grossman, Alec et al. (2017) Cryo-EM maps reveal five-fold channel structures and their modification by gatekeeper mutations in the parvovirus minute virus of mice (MVM) capsid. Virology 510:216-223|
|Meir, Chen; Mincberg, Michal; Rostovsky, Irina et al. (2017) The MVMp P4 promoter is a host cell-type range determinant in vivo. Virology 506:141-151|
|Nakaya, Yuki; Stavrou, Spyridon; Blouch, Kristin et al. (2016) In Vivo Examination of Mouse APOBEC3- and Human APOBEC3A- and APOBEC3G-Mediated Restriction of Parvovirus and Herpesvirus Infection in Mouse Models. J Virol 90:8005-12|
|Mihaylov, Ivailo S; Cotmore, Susan F; Tattersall, Peter (2014) Complementation for an essential ancillary non-structural protein function across parvovirus genera. Virology 468-470:226-37|
|Vollmers, Ellen M; D'Abramo Jr, Anthony; Cotmore, Susan F et al. (2014) Genome sequence of tumor virus x, a member of the genus protoparvovirus in the family parvoviridae. Genome Announc 2:|
|Halder, Sujata; Cotmore, Susan; Heimburg-Molinaro, Jamie et al. (2014) Profiling of glycan receptors for minute virus of mice in permissive cell lines towards understanding the mechanism of cell recognition. PLoS One 9:e86909|
|Cotmore, Susan F; Agbandje-McKenna, Mavis; Chiorini, John A et al. (2014) The family Parvoviridae. Arch Virol 159:1239-47|
|Li, Lei; Cotmore, Susan F; Tattersall, Peter (2013) Parvoviral left-end hairpin ears are essential during infection for establishing a functional intranuclear transcription template and for efficient progeny genome encapsidation. J Virol 87:10501-14|
|Vollmers, Ellen M; Tattersall, Peter (2013) Distinct host cell fates for human malignant melanoma targeted by oncolytic rodent parvoviruses. Virology 446:37-48|
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