Biology subjects

Warrick, J. I.

Publications and source records attributed to Warrick, J. I..

5 recordsLinked to original sources

bioRxiv2026

Epithelial to mesenchymal transition and M2 macrophages drive aggressiveness in murine and human sarcomatoid urothelial carcinoma.

Patients with majority variant subtype histology including sarcomatoid urothelial carcinoma (SUC) have poor outcomes and limited treatment options, and there are few preclinical resources to investigate rare histologic subtypes. We developed three novel variant subtype histology bladder cancer (BC) cell lines by finding that basal BC tumor cells derived from mice treated with N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) were initially not competent to grow in immune competent mice, but then acquired tumorigenicity following passaging (recycling) in mice lacking mature B and T cells. Three genitourinary oncology pathologists identified BBN966 as SUC, BBN964 as a hybrid between SUC and squamous, and BBN975 as squamous, and each had unique growth characteristics. Using a publicly available dataset and our spatial transcriptomics analysis of a cohort of human tumors with mixed SUC and UC as comparators, we found that consistent with human SUC, BBN966 lack expression of basal and luminal genes. Consistent with human SUC and spatial transcriptomics analysis of canine SUC, BBN966 had the highest epithelial to mesenchymal transition (EMT) upregulation, and all three recycled tumor cells had increased EMT pathway expression in recycled tumor cells. Moreover, increased expression of genes upregulated in all three recycled tumor cells associated with worse overall survival in patients with muscle invasive UC. Similar to human SUC, BBN966 tumors had higher proportion of M2 macrophage gene expression. Finally, we found in the largest cohort of PD-L1 IHC to date that 20 of 38 (52.6%) human SUC had CPS > 50, which was driven mostly by tumor proportion score. Consistent with this, we found anti-PD1 immune checkpoint inhibitor (ICI) significantly inhibited BBN966 tumor growth, while the hybrid BBN964 tumors had mixed response to ICI. Thus, the murine BBN966 tumors exhibited similarities to human SUC, and can be used to examine novel therapies for translation into future SUC clinical studies.

cancer biology↗

bioRxiv2023

Urothelium-specific expression of mutationally activated Pik3ca initiates early lesions of non-invasive bladder cancer

Despite the fact that [~]70% of bladder cancers are non-invasive and have high recurrence rates, early stage disease is understudied. The relative lack of models to validate the contribution of molecular drivers of bladder tumorigenesis is a significant issue. While mutations in PIK3CA are frequent in human bladder cancer, an in vivo model for understanding their contribution to bladder tumorigenesis is unavailable. Therefore, a Upk2-Cre/Pik3caH1047R mouse model expressing one or two R26-Pik3caH1047R alleles in a urothelium-specific manner was created. Pik3caH1047R functionality was confirmed by quantifying Akt phosphorylation and mice were characterized by assessing urothelial thickness, nuclear atypia, and expression of luminal and basal markers at 6 and 12 months of age. At 6 months, Pik3caH1047R mice developed increased urothelial thickness and nuclear atypia, however, at 12 months, Pik3caH1047R mice did not exhibit progressive disease. Immunohistochemistry shows urothelium maintained luminal differentiation characterized by high Foxa1 and Ppar{gamma} expression. In addition, mice were subjected to low-dose carcinogen exposure (N-Butyl-N-(4-hydroxybutyl)nitrosamine (BBN)). Surprisingly, Pik3caH1047R mice exhibited no significant differences after exposure relative to mice without exposure. Furthermore, ssGSEA analysis of invasive human tumors showed those with mutant PIK3CA do not exhibit significantly increased PI3K/AKT pathway activity compared to wildtype PIK3CA tumors. Overall, these data suggest that Pik3caH1047R can elicit early tumorigenic changes in the urothelium, but progression to invasion may require additional genetic alterations.

cancer biology↗

bioRxiv2020

Loss of the Pioneer Factor FOXA1 Results in Genome-wide Epigenetic Reprogramming and activation of Interferon-Response Genes including CD274/PD-L1

Forkhead Box A1 (FOXA1) is a pioneer transcription factor critical in epigenetic regulation of chromatin and cell fate determination. Reduced FOXA1 expression is an independent predictor of poor overall survival in bladder cancer patients. However, the impact of FOXA1 loss on chromatin epigenetics in bladder cancer is unknown. Therefore, we determined the impact of FOXA1 knock out (KO) on epigenetic modification of chromatin and associated gene expression. We identified 8,230 differentially expressed genes following FOXA1 KO. Surprisingly, Gene Set Enrichment Analysis (GSEA) identified IFN[a]/{gamma} gene expression signatures as enriched following FOXA1 KO. FOXA1 KO induced both increased and decreased numbers of histone 3 lysine 27 acetylation (H3K27ac) sites throughout the genome. As expected, the majority of differences in H3K27ac across genomic areas in FOXA1 KO cells is mapped to intergenic and intronic regions where enhancers reside. In addition, a subset of differential H3K27ac levels were also mapped to proximal promoters and within gene bodies. Integrated analysis of RNA/ChIP-seq data shows changes in gene expression that are mirrored by differences in H3K27ac. Motif analysis of DNA sequence enriched for H3K27ac identified significant increases in transcription factor binding motifs including the interferon sensitive response element (ISRE) and interferon response factors such as IRF1. Moreover, we identified increased H3K27ac of regulatory elements as being associated with several upregulated interferon sensitive genes (ISGs) in FOXA1 KO cells, including CD274/PD-L1. Western blotting and Q-RT-PCR confirmed upregulation of CD274/PD-L1 following FOXA1 KO. Analysis of TCGA data confirmed an inverse relationship between FOXA1 and CD274 in bladder cancer, as well as in other cancers. In summary, we provide evidence of widespread epigenetic reprogramming after FOXA1 KO in bladder cancer cells. Additionally, we provide evidence that FOXA1 KO-induced epigenetic changes contribute to activation of a global interferon-dominant expression signature, including the immune checkpoint target CD274/PD-L1 in a cancer cell-intrinsic manner.

cancer biology↗

bioRxiv2019

Context-dependent activation of SIRT3 is necessary for anchorage-independent survival and metastasis of ovarian cancer cells.

Cells must alter their antioxidant capacity for maximal metastatic potential. However, the antioxidant adaptations required for transcoelomic metastasis, which is the passive dissemination of cancer cells in the peritoneal cavity as seen in ovarian cancer, have largely remained unexplored. Contradicting the need for oxidant scavenging by tumor cells is the observation that expression of the nutrient stress sensor and regulator of mitochondrial antioxidant defenses, SIRT3, is suppressed in many primary tumors. We discovered that this mitochondrial deacetylase is however, upregulated in a context-dependent manner in cancer cells. SIRT3 activity and expression transiently increased following ovarian cancer cell detachment and in tumor cells derived from malignant ascites of high-grade serous adenocarcinoma patients. Mechanistically, SIRT3 prevents mitochondrial superoxide surges in detached cells by regulating the manganese superoxide dismutase SOD2. This mitochondrial stress response is under dual regulation by SIRT3. SIRT3 rapidly increases SOD2 activity as an early adaptation to cellular detachment, which is followed by SIRT3-dependent transcriptional increases in SOD2 during sustained anchorage-independence. In addition, SIRT3 inhibits glycolytic capacity in anchorage-independent cells thereby contributing to metabolic changes in response to detachment. While manipulation of SIRT3 expression has few deleterious effects on cancer cells in attached conditions, SIRT3 up-regulation and SIRT3-mediated oxidant scavenging following matrix detachment are required for anoikis resistance in vitro, and both SIRT3 and SOD2 are necessary for colonization of the peritoneal cavity in vivo. Our results highlight the novel context-specific, pro-metastatic role of SIRT3 in ovarian cancer.

cancer biology↗

bioRxiv2018

Repression of Transcription Factor AP-2 Alpha by Peroxisome Proliferator Activated Receptor Gamma Reveals a Novel Transcriptional Circuit in basal-squamous Bladder Cancer

The discovery of bladder cancer transcriptional subtypes provides an opportunity to identify high risk patients, and tailor disease management. Recent studies suggest tumor heterogeneity contributes to \"plasticity\" of molecular subtype during progression and following treatment. Nonetheless, the transcriptional drivers of the aggressive basal-squamous subtype remain unidentified. As PPAR{gamma} has been repeatedly implicated in the luminal subtype of bladder cancer, we hypothesized inactivation of this transcriptional master regulator during progression results in increased expression of basal-squamous specific transcription factors (TFs) which act to drive aggressive behavior. We initiated a pharmacologic and RNA-seq-based screen to identify PPAR{gamma}-repressed, basal-squamous specific TFs. Hierarchical clustering of RNA-seq data following treatment of a panel of human bladder cancer cell lines with a PPAR{gamma} agonist identified a number of TFs regulated by PPAR{gamma} activation, several of which are implicated in urothelial and squamous differentiation. One PPAR{gamma}-repressed TF implicated in squamous differentiation identified is Transcription Factor Activating Protein 2 alpha (TFAP2A). We show TFAP2A and its paralog TFAP2C are overexpressed in basal-squamous bladder cancer and in squamous areas of cystectomy samples, and that overexpression is associated with increased lymph node metastasis and distant recurrence, respectively. Biochemical analysis confirmed the ability of PPAR{gamma} activation to repress TFAP2A, while PPAR{gamma} antagonist studies indicate the requirement of a functional receptor. In vivo tissue recombination studies show TFAP2A and TFAP2C promote tumor growth in line with the aggressive nature of basal-squamous bladder cancer. Our findings suggest PPAR{gamma} inactivation, as well as TFAP2A and TFAP2C overexpression cooperate with other TFs to promote the basal-squamous transition.

cancer biology↗