Abstract 1506: Diminished migration potential of MDA-MB-231Br (brain-seeking) breast cancer cell line with integration of keratin 18 gene
Authors: Johnson Anissa , Liu Tuoen , Lockman Paul , Szalai Gabor 
Published: March 2024

Abstract
Triple-negative breast cancer is considered to have one of the poorest prognostic outcomes of the breast cancer subtypes, with brain metastasis resulting in a survival rate of less than a year. Determining and eventually targeting the cause of the triple-negative breast cancer cells that seek the brain would improve life expectancy and quality of life by preventing the ramifications of brain pathology. Through a novel mouse model, previous research has demonstrated that one sub-line of the MDA-MB-231 (triple-negative breast cancer cell line) cells, MDA-MB-231Br, preferentially metastasizes to the brain. Additionally, lower levels of expression of the keratin 18 gene were observed in the MDA-MB-231Br cells, which prompted the analysis of the transcriptional control of the keratin 18 gene. In our previous study, we analyzed the pattern of chromatin occupation of transcription factors FLI1 and ETS1 to understand the transcriptional control of keratin 18 within the parental MDA-MB-231 cell line and MDA-MB-231Br brain-seeking counterpart. Notably, the ETS1 transcription factor was enriched in the MDA-MB-231Br cells, and the FLI1 transcription factor was enriched in the MDA-MB-231 cells. In this study, using transient and stable transfection, we incorporated keratin 18 cDNA into the MDA-MB-231Br cells and examined the effect on their migration capabilities. We hypothesized that with the introduction of keratin 18 cDNA into the MDA-MB-231Br cells, their migration capabilities would match that of their parental counterpart.
The MDA-MB-231Br cells were cultured in the Burrell research laboratory, and transfections were performed using Lipofectamine™ 3000 Transfection Reagent by Thermo Scientific with GFP as a control. Migration assays were performed using a transwell migration assay (Millipore) and with a wound healing assay.
Ultimately, our results from both migration and wound healing assays demonstrated a diminished migration capability after keratin 18 was re-introduced into the MDA-MB-231Br cells through transfection. In the wound healing assay, the MDA-MB-231Br cells transfected with keratin 18 closely resembled the pattern of migration demonstrated by the parental MDA-MB-231 cells, while the MDA-MB-231Br cells transfected with GFP followed the pattern of the untouched MDA-MB-231Br cells. Additionally, the migration assay showed significantly less migratory capability of the MDA-MB-231Br cells expressing keratin 18 compared to the MDA-MB-231Br cells expressing GFP as a control (p &lt;0.05). The invasion capabilities of these cells with and without the presence of keratin 18 will be evaluated next to further elucidate the effects of re-expressing keratin 18.
Citation Format: Anissa Johnson, Tuoen Liu, Paul Lockman, Gabor Szalai. Diminished migration potential of MDA-MB-231Br (brain-seeking) breast cancer cell line with integration of keratin 18 gene [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1506.