Presentation: 2025 ND EPSCoR Annual conference 

October 21, 2025, NDSU Memorial Union, Fargo, North Dakota

Investigating the Role of the Transcription Factor Grainyhead-like 1 in Urothelial Carcinoma

Urothelial carcinoma (UC) is the 6th most prevalent cancer in the United States and ranks 10th for deaths in the United States due to cancer. A defining feature of aggressive UC is the histological identification of squamous differentiation (SD) within the tumors. UC tumors with SD are characterized by expression of the basal keratins (KRT 5, 6, and 14). The role of grainyhead-like 1 (GRHL1) transcription factor in UC has not been elucidated but its expression is elevated in tumor vs normal tissue, and it is enriched in areas of SD. We hypothesized that GRHL1is regulating genes that define the basal/squamous (Ba/Sq) subtype of UC. To investigate this, we generated GRHL1 knockdown (GRHL1 KD) UC cell lines using lentiviral transduction with shRNAs targeting human GRHL1 compared to scramble shRNA control cells. To confirm GRHL1 KD and evaluate effects on basal keratin expression, we performed qPCR and Western Blot analysis. We also performed luciferase growth assays, flow cytometry-based cell cycle analysis, and quantitative proteomics. The attenuation of GRHL1 had variable effects on basal keratin expression across the cell lines. However, GRHL1 KD cells displayed reduced cellular growth rates and had disrupted cell cycle progression compared to control cells. Proteomics identified decreased expression of ARL6IP1 (negative regulator of apoptosis) and increased expression of TXNIP (positive regulator of apoptosis) after GRHl1 KD. The results from our study indicate that GRHL1 promotes UC cell growth by evading apoptosis and that therapeutic strategies targeting GRHL1 may be effective in reducing UC tumor growth and/or metastasis.