Medical Student Research Fellowship for Summer 2007

Mentor: Dr. Mark Mummert
Department: Dermatology
Room number: F4.216A
Mail Code: 9069
Phone number: (214)648-4593
E-mail: mark.mummert@utsouthwestern.edu

Project I title: Impact of hyaluronan on the motility of squamous cell carcinomas in vitro

Human subjects IRB approved project number (where applicable): N/A

Animal subjects IRB approved project number (where applicable): N/A

Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Basic

Brief Description of Project:

Hyaluronan (HA) is a high molecular weight glycosaminoglycan that may have multiple roles in the progression of squamous cell carcinomas (SCC), including their metastasis. In a single report, well differentiated SCCs were shown to have higher concentrations of cell associated HA compared with poorly differentiated SCCs as assessed by histology (1). Because poorly differentiated SCCs are thought to have an increased capacity to metastasize compared with their non-metastatic counterparts, these investigators proposed that decreased expression of HA may be correlated with increased SCC motility and consequent metastasis (1). On the other hand, this study lacked the clinicopathology data to support a link between decreased HA expression and increased metastatic disease. As a first step in evaluating the potential role of HA in the motility of SCCs, we propose to compare SW-954 and SW-962 human SCC lines in vitro. The SW-954 line is a primary SCC from the vulva and the SW-962 line is from a lymph node metastatic to the vulva. In brief, we will compare the mRNA expression profiles of the three HA synthases (HAS1, HAS2 and HAS3) which express HA polymers using real-time PCR. We will also directly compare HA synthesis between SW-954 and SW-962 cells using metabolic labeling techniques. Finally, we will assess the motility of SW-954 and SW-962 cells using locomotor assays. This study should provide important new insights regarding the potential role of HA in the motility of SCC.

Project II title: Development of dermatan sulfate binding peptides

Human subjects IRB approved project number (where applicable): N/A

Animal subjects IRB approved project number (where applicable): N/A

Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Basic

Brief Description of Project:

Dermatan sulfate (DS, also known as chondroitin sulfate B) is a glycosaminoglycan composed of N-acetylgalactosamine and iduronic acid subunits. DS is found in high concentrations in the skin and is covalently attached to a number of different proteoglycans, including decorin, biglycan and versican. Despite the chemical simplicity of DS, this carbohydrate has been implicated in a number of diverse biological activities, including the cutaneous immune response and wound repair. However, most investigations have focused on the proteoglycan protein core rather than the attached DS side chain. The paucity of information regarding DS is a result of the lack of available tools. In order to develop new reagents to study the structure and function of DS we have employed a peptide phage display panning technique. Briefly, a phage library expressing random 12-mer peptides on the pIII minor coat protein were added to tissue culture plates coated with highly purified DS. After extensive washing the plates were treated with chondroitinase ABC to specifically elute those phages bound to DS co-polymers. We have now selected 10 phage clones for further analysis. Briefly, we propose to test the binding of these phage clones to DS and related glycosaminoglycans (chondroitin sulfate A, chondoroitin sulfate C, heparan sulfate and hyaluronan) using an ELISA-like plate assay. The peptide sequences of clones that show high binding to DS and low cross-reactivity to other glycosaminglycans will be deduced by sequencing the single-stranded DNA isolated from the phage clones. We will then order biotin labeled synthetic peptides and assess if these peptides retain their binding specificity in vitro. Finally, we will test the binding of biotinylated peptides to biologically relevant forms of DS in skin using histology. The development of DS-binding peptides may be an entirely new tool for studying this glycosaminoglycan.

1) Karvinen S, Kosma VM, Tammi MI, Tammi R. Hyaluronan, CD44 and versican in epidermal keratinocyte tumors (2003) Br J Dermatol 148:86-94.

Previous Research Activities or Publications with Medical Students:

Zmolik JM, Mummert ME. Pep-1 as a novel probe for the in situ detection of hyaluronan. (2005) J Histochem Cytochem 53:745-752.

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