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372 HMGB1 Localization as a Driver of Carcinogenesis in RDEB-Associated Squamous Cell Carcinoma

Published online by Cambridge University Press:  24 April 2023

Kacey Guenther Bui
Affiliation:
University of Minnesota
Anja Bielinsky
Affiliation:
University of Virginia
Hai Dang Nguyen
Affiliation:
University of Minnesota
Jakub Tolar
Affiliation:
University of Minnesota
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Abstract

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OBJECTIVES/GOALS: This study investigates whether localization of high mobility group box 1 (HMGB1) controls inflammatory signaling and DNA damage response in human keratinocytes, the cell of origin for squamous cell carcinoma (SCC). SCC is especially metastatic in chronic wounds, burns, and in patients with recessive dystrophic epidermolysis bullosa (RDEB). METHODS/STUDY POPULATION: We used CRISPR/Cas9 gene-editing to knock out HMGB1 in a keratinocyte line, p16INK4a-negative keratinocytes immortalized by ectopic hTERT expression (N/TERT-2G [46,XY]). Following gene editing, clonal keratinocyte populations were screened for knockout by PCR followed by TIDE analysis (Tracking of Indels by Decomposition) to identify indels that would result in a frameshift mutation. Total cell lysates for each clonal population were analyzed by immunoblot and immunofluorescence for HMGB1 protein. These cells will be used to assay for DNA damage sensitivity in the presence of genotoxic agents (etoposide, ultraviolet radiation, γ-irradiation). A lentiviral vector will then be used to express mutant forms of HMGB1 that localize to the nucleus (C23/45S) or cytoplasm (C106S) and DNA damage assays repeated. RESULTS/ANTICIPATED RESULTS: We have confirmed by sequencing, immunoblot, and immunofluorescence that HMGB1 is knocked out in a clonal population of N/TERT-2G human keratinocyte cells. We anticipate that cells with a complete absence of HMGB1 will have high sensitivity to DNA damaging agents, but little change in inflammatory signaling. We also expect that cells expressing mutant HMGB1 that localizes exclusively to the cytoplasm will demonstrate an increased sensitivity to DNA damage relative to wild-type controls, while mutant HMGB1 that localizes exclusively to the nucleus will be protected from DNA damage caused by exposure to genotoxic agents. DISCUSSION/SIGNIFICANCE: HMGB1 is a nuclear protein and damage associated molecular pattern that is elevated systemically in patients with RDEB, many of whom will go on to develop metastatic squamous cell carcinoma. The experiments described here investigate whether HMGB1 plays a mechanistic role in skin carcinogenesis via regulation of the DNA damage response.

Type
Precision Medicine/Health
Creative Commons
Creative Common License - CCCreative Common License - BYCreative Common License - NCCreative Common License - ND
This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use or in order to create a derivative work.
Copyright
© The Author(s), 2023. The Association for Clinical and Translational Science