Smith HA

Heath graduated in 2012.

Graduate Research Focus

Heath Smith is a research assistant in the McArdle Cancer Biology Research training program. He joined the McNeel lab in the fall of 2007, and has had a number of research projects and interests. The main focus of his thesis research is to evaluate the cancer testis antigen (CTA) synovial sarcoma X chromosome breakpoint 2 (SSX-2) as an immunotherapeutic target for the treatment of prostate cancer. SSX-2 expression has been demonstrated in prostate cancer at both the protein and mRNA level, particularly in advanced-stage disease, as well as a number of other types of malignancy. SSX-2 is a member of a multigene family of cancer testis antigens; a highly homologous family of proteins encoded by ten unique genes all located on the X chromosome. Recently these proteins have been identified as high-priority targets for cancer therapy based upon certain pre-defined criteria such as antigen specificity, oncogenicty, expression level, and number of identified epitopes [1].

Currently, Heath is evaluating a plasmid DNA vaccine encoding the human SSX-2 cDNA. He is testing the in vivo efficacy of the vaccine to elicit SSX-2 peptide-specific CD8+ T cells and CTL that can lyse prostate cancer cells; with the vaccine also serving as a genetic tool to identify immunogenic epitopes from the amino acid sequence of SSX-2. For these immunization studies he is using the A2/DR1 transgenic mouse; a murine model with a "humanized" immune system expressing human class I and class II MHC alleles. To evaluate this vaccine for immunogenicity and to identify peptide-specific T cells, Heath uses a variety of immune-based assays including ELISpot assay, T2 binding assay, LDH cytotoxicity assay, tetramer staining, etc. Human peripheral blood samples from healthy donors or prostate cancer patients have also been evaluated for the presence of SSX-2 peptide-specific T cells and CTL that can be cultured and lyse prostate cancer cells.

In addition to the DNA vaccine, Heath is also interested in the ability to upregulate the expression of SSX-2 and other SSX protein family members in prostate cancer cell lines using epigenetic modifying agents such as the DNA methyltransferase inhibitor 5'-aza-2' deoxycytodine. Using in vitro cell culture, Western blot, RT-PCR, qRT-PCR, and IHC Heath has been evaluating the expression of these SSX family members in prostate cancer cell lines, normal prostate epithelial cells, and human prostate cancer tissues.

Several other research projects and techniques being employed by Heath include serological analysis of recombinant cDNA expression libraries (SEREX) to identify antibodies specific to antigens such as SSX-2 in the sera of prostate cancer patients, modified SSX-2 vaccines to assess whether vaccine efficacy can be enhanced by making mutations in the plasmid by site-directed mutagenesis to increase peptide avidity for MHC class I, and evaluating the ability to elicit immune responses to multiple prostate cancer antigens through combinatorial vaccine delivery of DNA plasmids encoding prostate tumor-associated proteins.