Browsing by Author "Ware, Kathryn E"

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Characterization of a castrate-resistant prostate cancer xenograft derived from a patient of West African ancestry.
    (Prostate cancer and prostatic diseases, 2021-10-13) Patierno, Brendon M; Foo, Wen-Chi; Allen, Tyler; Somarelli, Jason A; Ware, Kathryn E; Gupta, Santosh; Wise, Sandra; Wise, John P; Qin, Xiaodi; Zhang, Dadong; Xu, Lingfan; Li, Yanjing; Chen, Xufeng; Inman, Brant A; McCall, Shannon J; Huang, Jiaoti; Kittles, Rick A; Owzar, Kouros; Gregory, Simon; Armstrong, Andrew J; George, Daniel J; Patierno, Steven R; Hsu, David S; Freedman, Jennifer A

    Background

    Prostate cancer is a clinically and molecularly heterogeneous disease, with highest incidence and mortality among men of African ancestry. To date, prostate cancer patient-derived xenograft (PCPDX) models to study this disease have been difficult to establish because of limited specimen availability and poor uptake rates in immunodeficient mice. Ancestrally diverse PCPDXs are even more rare, and only six PCPDXs from self-identified African American patients from one institution were recently made available.

    Methods

    In the present study, we established a PCPDX from prostate cancer tissue from a patient of estimated 90% West African ancestry with metastatic castration resistant disease, and characterized this model's pathology, karyotype, hotspot mutations, copy number, gene fusions, gene expression, growth rate in normal and castrated mice, therapeutic response, and experimental metastasis.

    Results

    This PCPDX has a mutation in TP53 and loss of PTEN and RB1. We have documented a 100% take rate in mice after thawing the PCPDX tumor from frozen stock. The PCPDX is castrate- and docetaxel-resistant and cisplatin-sensitive, and has gene expression patterns associated with such drug responses. After tail vein injection, the PCPDX tumor cells can colonize the lungs of mice.

    Conclusion

    This PCPDX, along with others that are established and characterized, will be useful pre-clinically for studying the heterogeneity of prostate cancer biology and testing new therapeutics in models expected to be reflective of the clinical setting.
  • Thumbnail Image
    ItemOpen Access
    Mesenchymal-Epithelial Transition in Sarcomas Is Controlled by the Combinatorial Expression of MicroRNA 200s and GRHL2.
    (Mol Cell Biol, 2016-10-01) Somarelli, Jason A; Shetler, Samantha; Jolly, Mohit K; Wang, Xueyang; Bartholf Dewitt, Suzanne; Hish, Alexander J; Gilja, Shivee; Eward, William C; Ware, Kathryn E; Levine, Herbert; Armstrong, Andrew J; Garcia-Blanco, Mariano A
    Phenotypic plasticity involves a process in which cells transiently acquire phenotypic traits of another lineage. Two commonly studied types of phenotypic plasticity are epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). In carcinomas, EMT drives invasion and metastatic dissemination, while MET is proposed to play a role in metastatic colonization. Phenotypic plasticity in sarcomas is not well studied; however, there is evidence that a subset of sarcomas undergo an MET-like phenomenon. While the exact mechanisms by which these transitions occur remain largely unknown, it is likely that some of the same master regulators that drive EMT and MET in carcinomas also act in sarcomas. In this study, we combined mathematical models with bench experiments to identify a core regulatory circuit that controls MET in sarcomas. This circuit comprises the microRNA 200 (miR-200) family, ZEB1, and GRHL2. Interestingly, combined expression of miR-200s and GRHL2 further upregulates epithelial genes to induce MET. This effect is phenocopied by downregulation of either ZEB1 or the ZEB1 cofactor, BRG1. In addition, an MET gene expression signature is prognostic for improved overall survival in sarcoma patients. Together, our results suggest that a miR-200, ZEB1, GRHL2 gene regulatory network may drive sarcoma cells to a more epithelial-like state and that this likely has prognostic relevance.
  • Thumbnail Image
    ItemOpen Access
    Snail promotes resistance to enzalutamide through regulation of androgen receptor activity in prostate cancer.
    (Oncotarget, 2016-08-02) Ware, Kathryn E; Somarelli, Jason A; Schaeffer, Daneen; Li, Jing; Zhang, Tian; Park, Sally; Patierno, Steven R; Freedman, Jennifer; Foo, Wen-Chi; Garcia-Blanco, Mariano A; Armstrong, Andrew J
    Treatment with androgen-targeted therapies can induce upregulation of epithelial plasticity pathways. Epithelial plasticity is known to be important for metastatic dissemination and therapeutic resistance. The goal of this study is to elucidate the functional consequence of induced epithelial plasticity on AR regulation during disease progression to identify factors important for treatment-resistant and metastatic prostate cancer. We pinpoint the epithelial plasticity transcription factor, Snail, at the nexus of enzalutamide resistance and prostate cancer metastasis both in preclinical models of prostate cancer and in patients. In patients, Snail expression is associated with Gleason 9-10 high-risk disease and is strongly overexpressed in metastases as compared to localized prostate cancer. Snail expression is also elevated in enzalutamide-resistant prostate cancer cells compared to enzalutamide-sensitive cells, and downregulation of Snail re-sensitizes enzalutamide-resistant cells to enzalutamide. While activation of Snail increases migration and invasion, it is also capable of promoting enzalutamide resistance in enzalutamide-sensitive cells. This Snail-mediated enzalutamide resistance is a consequence of increased full-length AR and AR-V7 expression and nuclear localization. Downregulation of either full-length AR or AR-V7 re-sensitizes cells to enzalutamide in the presence of Snail, thus connecting Snail-induced enzalutamide resistance directly to AR biology. Finally, we demonstrate that Snail is capable of mediating-resistance through AR even in the absence of AR-V7. These findings imply that increased Snail expression during progression to metastatic disease may prime cells for resistance to AR-targeted therapies by promoting AR activity in prostate cancer.