Publications by authors named "Kathryn E Ware"

20 Publications

  • Page 1 of 1

Characterization of a castrate-resistant prostate cancer xenograft derived from a patient of West African ancestry.

Prostate Cancer Prostatic Dis 2021 Oct 13. Epub 2021 Oct 13.

Department of Medicine, Division of Medical Oncology, Duke University School of Medicine, Durham, NC, 27710, USA.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41391-021-00460-yDOI Listing
October 2021

A Comparative Oncology Drug Discovery Pipeline to Identify and Validate New Treatments for Osteosarcoma.

Cancers (Basel) 2020 Nov 11;12(11). Epub 2020 Nov 11.

Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.

Background: Osteosarcoma is a rare but aggressive bone cancer that occurs primarily in children. Like other rare cancers, treatment advances for osteosarcoma have stagnated, with little improvement in survival for the past several decades. Developing new treatments has been hampered by extensive genomic heterogeneity and limited access to patient samples to study the biology of this complex disease.

Methods: To overcome these barriers, we combined the power of comparative oncology with patient-derived models of cancer and high-throughput chemical screens in a cross-species drug discovery pipeline.

Results: Coupling in vitro high-throughput drug screens on low-passage and established cell lines with in vivo validation in patient-derived xenografts we identify the proteasome and CRM1 nuclear export pathways as therapeutic sensitivities in osteosarcoma, with dual inhibition of these pathways inducing synergistic cytotoxicity.

Conclusions: These collective efforts provide an experimental framework and set of new tools for osteosarcoma and other rare cancers to identify and study new therapeutic vulnerabilities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers12113335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7696249PMC
November 2020

A Precision Medicine Drug Discovery Pipeline Identifies Combined CDK2 and 9 Inhibition as a Novel Therapeutic Strategy in Colorectal Cancer.

Mol Cancer Ther 2020 12 6;19(12):2516-2527. Epub 2020 Nov 6.

Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina.

Colorectal cancer is the third most common cancer in the United States and responsible for over 50,000 deaths each year. Therapeutic options for advanced colorectal cancer are limited, and there remains an unmet clinical need to identify new treatments for this deadly disease. To address this need, we developed a precision medicine pipeline that integrates high-throughput chemical screens with matched patient-derived cell lines and patient-derived xenografts (PDX) to identify new treatments for colorectal cancer. High-throughput screens of 2,100 compounds were performed across six low-passage, patient-derived colorectal cancer cell lines. These screens identified the CDK inhibitor drug class among the most effective cytotoxic compounds across six colorectal cancer lines. Among this class, combined targeting of CDK1, 2, and 9 was the most effective, with ICs ranging from 110 nmol/L to 1.2 μmol/L. Knockdown of CDK9 in the presence of a CDK2 inhibitor (CVT-313) showed that CDK9 knockdown acted synergistically with CDK2 inhibition. Mechanistically, dual CDK2/9 inhibition induced significant G-M arrest and anaphase catastrophe. Combined CDK2/9 inhibition synergistically reduced PDX tumor growth. Our precision medicine pipeline provides a robust screening and validation platform to identify promising new cancer therapies. Application of this platform to colorectal cancer pinpointed CDK2/9 dual inhibition as a novel combinatorial therapy to treat colorectal cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1535-7163.MCT-20-0454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7718319PMC
December 2020

Development of a precision medicine pipeline to identify personalized treatments for colorectal cancer.

BMC Cancer 2020 Jun 24;20(1):592. Epub 2020 Jun 24.

Department of Medicine, Division of Medical Oncology, Duke University Medical Center, 3008 Snyderman Building, 905 S. LaSalle St., Durham, NC, 27710, USA.

Background: Metastatic colorectal cancer (CRC) continues to be a major health problem, and current treatments are primarily for disease control and palliation of symptoms. In this study, we developed a precision medicine strategy to discover novel therapeutics for patients with CRC.

Methods: Six matched low-passage cell lines and patient-derived xenografts (PDX) were established from CRC patients undergoing resection of their cancer. High-throughput drug screens using a 119 FDA-approved oncology drug library were performed on these cell lines, which were then validated in vivo in matched PDXs. RNA-Seq analysis was then performed to identify predictors of response.

Results: Our study revealed marked differences in response to standard-of-care agents across patients and pinpointed druggable pathways to treat CRC. Among these pathways co-targeting of fibroblast growth factor receptor (FGFR), SRC, platelet derived growth factor receptor (PDGFR), or vascular endothelial growth factor receptor (VEGFR) signaling was found to be an effective strategy. Molecular analyses revealed potential predictors of response to these druggable pathways.

Conclusions: Our data suggests that the use of matched low-passage cell lines and PDXs is a promising strategy to identify new therapies and pathways to treat metastatic CRC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12885-020-07090-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7313200PMC
June 2020

From the Clinic to the Bench and Back Again in One Dog Year: How a Cross-Species Pipeline to Identify New Treatments for Sarcoma Illuminates the Path Forward in Precision Medicine.

Front Oncol 2020 11;10:117. Epub 2020 Feb 11.

Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, United States.

Cancer drug discovery is an inefficient process, with more than 90% of newly-discovered therapies failing to gain regulatory approval. Patient-derived models of cancer offer a promising new approach to identify new treatments; however, for rare cancers, such as sarcomas, access to patient samples is limited, which precludes development of patient-derived models. To address the limited access to patient samples, we have turned to pet dogs with naturally-occurring sarcomas. Although sarcomas make up <1% of all human cancers, sarcomas represent 15% of cancers in dogs. Because dogs have similar immune systems, an accelerated pace of cancer progression, and a shared environment with humans, studying pet dogs with cancer is ideal for bridging gaps between mouse models and human cancers. Here, we present our cross-species personalized medicine pipeline to identify new therapies for sarcomas. We explore this process through the focused study of a pet dog, Teddy, who presented with six synchronous leiomyosarcomas. Using our pipeline we identified proteasome inhibitors as a potential therapy for Teddy. Teddy was treated with bortezomib and showed a varied response across tumors. Whole exome sequencing revealed substantial genetic heterogeneity across Teddy's recurrent tumors and metastases, suggesting that intra-patient heterogeneity and tumoral adaptation were responsible for the heterogeneous clinical response. Ubiquitin proteomics coupled with exome sequencing revealed multiple candidate driver mutations in proteins related to the proteasome pathway. Together, our results demonstrate how the comparative study of canine sarcomas offers important insights into the development of personalized medicine approaches that can lead to new treatments for sarcomas in both humans and canines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2020.00117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026496PMC
February 2020

E-Cadherin Represses Anchorage-Independent Growth in Sarcomas through Both Signaling and Mechanical Mechanisms.

Mol Cancer Res 2019 06 12;17(6):1391-1402. Epub 2019 Mar 12.

Department of Medicine, Duke University Medical Center, Durham, North Carolina.

CDH1 (also known as E-cadherin), an epithelial-specific cell-cell adhesion molecule, plays multiple roles in maintaining adherens junctions, regulating migration and invasion, and mediating intracellular signaling. Downregulation of E-cadherin is a hallmark of epithelial-to-mesenchymal transition (EMT) and correlates with poor prognosis in multiple carcinomas. Conversely, upregulation of E-cadherin is prognostic for improved survival in sarcomas. Yet, despite the prognostic benefit of E-cadherin expression in sarcoma, the mechanistic significance of E-cadherin in sarcomas remains poorly understood. Here, by combining mathematical models with wet-bench experiments, we identify the core regulatory networks mediated by E-cadherin in sarcomas, and decipher their functional consequences. Unlike carcinomas, E-cadherin overexpression in sarcomas does not induce a mesenchymal-to-epithelial transition (MET). However, E-cadherin acts to reduce both anchorage-independent growth and spheroid formation of sarcoma cells. Ectopic E-cadherin expression acts to downregulate phosphorylated CREB1 (p-CREB) and the transcription factor, TBX2, to inhibit anchorage-independent growth. RNAi-mediated knockdown of TBX2 phenocopies the effect of E-cadherin on CREB levels and restores sensitivity to anchorage-independent growth in sarcoma cells. Beyond its signaling role, E-cadherin expression in sarcoma cells can also strengthen cell-cell adhesion and restricts spheroid growth through mechanical action. Together, our results demonstrate that E-cadherin inhibits sarcoma aggressiveness by preventing anchorage-independent growth. IMPLICATIONS: We highlight how E-cadherin can restrict aggressive behavior in sarcomas through both biochemical signaling and biomechanical effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1541-7786.MCR-18-0763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548594PMC
June 2019

An Integrative Systems Biology and Experimental Approach Identifies Convergence of Epithelial Plasticity, Metabolism, and Autophagy to Promote Chemoresistance.

J Clin Med 2019 Feb 7;8(2). Epub 2019 Feb 7.

Duke Cancer Institute and the Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.

The evolution of therapeutic resistance is a major cause of death for cancer patients. The development of therapy resistance is shaped by the ecological dynamics within the tumor microenvironment and the selective pressure of the host immune system. These selective forces often lead to evolutionary convergence on pathways or hallmarks that drive progression. Thus, a deeper understanding of the evolutionary convergences that occur could reveal vulnerabilities to treat therapy-resistant cancer. To this end, we combined phylogenetic clustering, systems biology analyses, and molecular experimentation to identify convergences in gene expression data onto common signaling pathways. We applied these methods to derive new insights about the networks at play during transforming growth factor-β (TGF-β)-mediated epithelial⁻mesenchymal transition in lung cancer. Phylogenetic analyses of gene expression data from TGF-β-treated cells revealed convergence of cells toward amine metabolic pathways and autophagy during TGF-β treatment. Knockdown of the autophagy regulatory, ATG16L1, re-sensitized lung cancer cells to cancer therapies following TGF-β-induced resistance, implicating autophagy as a TGF-β-mediated chemoresistance mechanism. In addition, high ATG16L expression was found to be a poor prognostic marker in multiple cancer types. These analyses reveal the usefulness of combining evolutionary and systems biology methods with experimental validation to illuminate new therapeutic vulnerabilities for cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/jcm8020205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6406733PMC
February 2019

EMT and MET: necessary or permissive for metastasis?

Mol Oncol 2017 07 12;11(7):755-769. Epub 2017 Jun 12.

Center for Theoretical Biological Physics, Rice University, Houston, TX, USA.

Epithelial-to-mesenchymal transition (EMT) and its reverse mesenchymal-to-epithelial transition (MET) have been suggested to play crucial roles in metastatic dissemination of carcinomas. These phenotypic transitions between states are not binary. Instead, carcinoma cells often exhibit a spectrum of epithelial/mesenchymal phenotype(s). While epithelial/mesenchymal plasticity has been observed preclinically and clinically, whether any of these phenotypic transitions are indispensable for metastatic outgrowth remains an unanswered question. Here, we focus on epithelial/mesenchymal plasticity in metastatic dissemination and propose alternative mechanisms for successful dissemination and metastases beyond the traditional EMT/MET view. We highlight multiple hypotheses that can help reconcile conflicting observations, and outline the next set of key questions that can offer valuable insights into mechanisms of metastasis in multiple tumor models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/1878-0261.12083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496498PMC
July 2017

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells.

J Vis Exp 2017 04 7(122). Epub 2017 Apr 7.

Department of Medicine, Duke University;

Phenotypic plasticity refers to a phenomenon in which cells transiently gain traits of another lineage. During carcinoma progression, phenotypic plasticity drives invasion, dissemination and metastasis. Indeed, while most of the studies of phenotypic plasticity have been in the context of epithelial-derived carcinomas, it turns out sarcomas, which are mesenchymal in origin, also exhibit phenotypic plasticity, with a subset of sarcomas undergoing a phenomenon that resembles a mesenchymal-epithelial transition (MET). Here, we developed a method comprising the miR-200 family and grainyhead-like 2 (GRHL2) to mimic this MET-like phenomenon observed in sarcoma patient samples.We sequentially express GRHL2 and the miR-200 family using cell transduction and transfection, respectively, to better understand the molecular underpinnings of these phenotypic transitions in sarcoma cells. Sarcoma cells expressing miR-200s and GRHL2 demonstrated enhanced epithelial characteristics in cell morphology and alteration of epithelial and mesenchymal biomarkers. Future studies using these methods can be used to better understand the phenotypic consequences of MET-like processes on sarcoma cells, such as migration, invasion, metastatic propensity, and therapy resistance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3791/55520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5564486PMC
April 2017

EGFR Mediates Responses to Small-Molecule Drugs Targeting Oncogenic Fusion Kinases.

Cancer Res 2017 07 20;77(13):3551-3563. Epub 2017 Apr 20.

Division of Medical Oncology, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado.

Oncogenic kinase fusions of , , , and act as drivers in human lung and other cancers. Residual tumor burden following treatment of ALK or ROS1 lung cancer patients with oncogene-targeted therapy ultimately enables the emergence of drug-resistant clones, limiting the long-term effectiveness of these therapies. To determine the signaling mechanisms underlying incomplete tumor cell killing in oncogene-addicted cancer cells, we investigated the role of EGFR signaling in drug-naïve cancer cells harboring these oncogene fusions. We defined three distinct roles for EGFR in the response to oncogene-specific therapies. First, EGF-mediated activation of EGFR blunted fusion kinase inhibitor binding and restored fusion kinase signaling complexes. Second, fusion kinase inhibition shifted adaptor protein binding from the fusion oncoprotein to EGFR. Third, EGFR enabled bypass signaling to critical downstream pathways such as MAPK. While evidence of EGFR-mediated bypass signaling has been reported after ALK and ROS1 blockade, our results extended this effect to RET and NTRK1 blockade and uncovered the other additional mechanisms in gene fusion-positive lung cancer cells, mouse models, and human clinical specimens before the onset of acquired drug resistance. Collectively, our findings show how EGFR signaling can provide a critical adaptive survival mechanism that allows cancer cells to evade oncogene-specific inhibitors, providing a rationale to cotarget EGFR to reduce the risks of developing drug resistance. .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-17-0109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516930PMC
July 2017

PhyloOncology: Understanding cancer through phylogenetic analysis.

Biochim Biophys Acta Rev Cancer 2017 Apr 31;1867(2):101-108. Epub 2016 Oct 31.

Department of Biostatistics, Yale University, United States; Department of Ecology and Evolutionary Biology, Yale University, United States; Department of Program in Computational Biology and Bioinformatics, Yale University, United States. Electronic address:

Despite decades of research and an enormity of resultant data, cancer remains a significant public health problem. New tools and fresh perspectives are needed to obtain fundamental insights, to develop better prognostic and predictive tools, and to identify improved therapeutic interventions. With increasingly common genome-scale data, one suite of algorithms and concepts with potential to shed light on cancer biology is phylogenetics, a scientific discipline used in diverse fields. From grouping subsets of cancer samples to tracing subclonal evolution during cancer progression and metastasis, the use of phylogenetics is a powerful systems biology approach. Well-developed phylogenetic applications provide fast, robust approaches to analyze high-dimensional, heterogeneous cancer data sets. This article is part of a Special Issue entitled: Evolutionary principles - heterogeneity in cancer?, edited by Dr. Robert A. Gatenby.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbcan.2016.10.006DOI Listing
April 2017

Whole Genomic Copy Number Alterations in Circulating Tumor Cells from Men with Abiraterone or Enzalutamide-Resistant Metastatic Castration-Resistant Prostate Cancer.

Clin Cancer Res 2017 Mar 6;23(5):1346-1357. Epub 2016 Sep 6.

Department of Medicine, Division of Medical Oncology, Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina.

Beyond enumeration, circulating tumor cells (CTCs) can provide genetic information from metastatic cancer that may facilitate a greater understanding of tumor biology and enable a precision medicine approach. CTCs and paired leukocytes from men with metastatic castration-resistant prostate cancer (mCRPC) were isolated from blood through red cell lysis, CD45 depletion, and flow sorting based on EpCAM/CD45 expression. We next performed whole genomic copy number analysis of CTCs and matched patient leukocytes (germline) using array-based comparative genomic hybridization (aCGH) from 16 men with mCRPC, including longitudinal and sequential aCGH analyses of CTCs in the context of enzalutamide therapy. All patients had mCRPC and primary or acquired resistance to abiraterone acetate or enzalutamide. We compiled copy gains and losses, with a particular focus on those genes highly implicated in mCRPC progression and previously validated as being aberrant in metastatic tissue samples and genomic studies of reference mCRPC datasets. Genomic gains in >25% of CTCs were observed in , and , while common genomic losses involved , and Analysis of aCGH in a sample with sequential enzalutamide-resistant visceral progression showed acquired loss of amplification concurrent with gain of , consistent with evolution toward a neuroendocrine-like, AR-independent clone. Genomic analysis of pooled CTCs in men with mCRPC suggests a reproducible, but highly complex molecular profile that includes common aberrations in , and PI3K signaling during mCRPC progression, which may be useful for predictive biomarker development. .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-16-1211DOI Listing
March 2017

Snail promotes resistance to enzalutamide through regulation of androgen receptor activity in prostate cancer.

Oncotarget 2016 Aug;7(31):50507-50521

Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, NC, USA.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.10476DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5226599PMC
August 2016

Mesenchymal-Epithelial Transition in Sarcomas Is Controlled by the Combinatorial Expression of MicroRNA 200s and GRHL2.

Mol Cell Biol 2016 10 12;36(19):2503-13. Epub 2016 Sep 12.

Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA Program in Molecular Genetics and Genomics, Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina, USA Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/MCB.00373-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5021378PMC
October 2016

Biologic and clinical significance of androgen receptor variants in castration resistant prostate cancer.

Endocr Relat Cancer 2014 Aug 23;21(4):T87-T103. Epub 2014 May 23.

Departments of Molecular Genetics and MedicineDuke University, 213 Research Dr, 0045 CARL Building, Durham, North Carolina 27710, USADepartment of MedicineDuke Cancer Institute, Duke University, Durham, North Carolina, USAMasonic Cancer CenterUniversity of Minnesota Masonic Cancer Center, Mayo Mail Code 806, 420 Delaware Street SE, Minneapolis, Minnesota 55455, USADepartment of Laboratory Medicine and PathologyUniversity of Minnesota, Minneapolis, Minnesota, USADepartments of Molecular Genetics and MedicineDuke University, 213 Research Dr, 0045 CARL Building, Durham, North Carolina 27710, USADepartment of MedicineDuke Cancer Institute, Duke University, Durham, North Carolina, USAMasonic Cancer CenterUniversity of Minnesota Masonic Cancer Center, Mayo Mail Code 806, 420 Delaware Street SE, Minneapolis, Minnesota 55455, USADepartment of Laboratory Medicine and PathologyUniversity of Minnesota, Minneapolis, Minnesota, USA

As prostate cancer (PCa) progresses to the lethal castration resistant and metastatic form, genetic and epigenetic adaptation, clonal selection, and evolution of the tumor microenvironment contribute to the emergence of unique biological characteristics under the selective pressure of external stresses. These stresses include the therapies applied in the clinic or laboratory and the exposures of cancers to hormonal, paracrine, or autocrine stimuli in the context of the tumor micro- and macro-environment. The androgen receptor (AR) is a key gene involved in PCa etiology and oncogenesis, including disease development, progression, response to initial hormonal therapies, and subsequent resistance to hormonal therapies. Alterations in the AR signaling pathway have been observed in certain selection contexts and contribute to the resistance to agents that target hormonal regulation of the AR, including standard androgen deprivation therapy, antiandrogens such as enzalutamide, and androgen synthesis inhibition with abiraterone acetate. One such resistance mechanism is the synthesis of constitutively active AR variants lacking the canonical ligand-binding domain. This review focuses on the etiology, characterization, biological properties, and emerging data contributing to the clinical characteristics of AR variants, and suggests approaches to full-length AR and AR variant biomarker validation, assessment, and systemic targeting in the clinic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1530/ERC-13-0470DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4277180PMC
August 2014

FGFR1 mRNA and protein expression, not gene copy number, predict FGFR TKI sensitivity across all lung cancer histologies.

Clin Cancer Res 2014 Jun 25;20(12):3299-309. Epub 2014 Apr 25.

Authors' Affiliations: Departments of Medicine, Pathology, Craniofacial Biology, and Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado; ARIAD Pharmaceuticals, Inc., Cambridge, Massachusetts; Medical University of Gdańsk, Poland; and Department of Prostate Cancer Research, Institute of Pathology, University Hospital of Bonn, Bonn, Germany

Purpose: FGFR1 gene copy number (GCN) is being evaluated as a biomarker for FGFR tyrosine kinase inhibitor (TKI) response in squamous cell lung cancers (SCC). The exclusive use of FGFR1 GCN for predicting FGFR TKI sensitivity assumes increased GCN is the only mechanism for biologically relevant increases in FGFR1 signaling. Herein, we tested whether FGFR1 mRNA and protein expression may serve as better biomarkers of FGFR TKI sensitivity in lung cancer.

Experimental Design: Histologically diverse lung cancer cell lines were submitted to assays for ponatinib sensitivity, a potent FGFR TKI. A tissue microarray composed of resected lung tumors was submitted to FGFR1 GCN, and mRNA analyses and the results were validated with The Cancer Genome Atlas (TCGA) lung cancer data.

Results: Among 58 cell lines, 14 exhibited ponatinib sensitivity (IC50 values ≤ 50 nmol/L) that correlated with FGFR1 mRNA and protein expression, but not with FGFR1 GCN or histology. Moreover, ponatinib sensitivity associated with mRNA expression of the ligands, FGF2 and FGF9. In resected tumors, 22% of adenocarcinomas and 28% of SCCs expressed high FGFR1 mRNA. Importantly, only 46% of SCCs with increased FGFR1 GCN expressed high mRNA. Lung cancer TCGA data validated these findings and unveiled overlap of FGFR1 mRNA positivity with KRAS and PIK3CA mutations.

Conclusions: FGFR1 dependency is frequent across various lung cancer histologies, and FGFR1 mRNA may serve as a better biomarker of FGFR TKI response in lung cancer than FGFR1 GCN. The study provides important and timely insight into clinical testing of FGFR TKIs in lung cancer and other solid tumor types.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-13-3060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4062100PMC
June 2014

Fibroblast growth factor receptors are components of autocrine signaling networks in head and neck squamous cell carcinoma cells.

Clin Cancer Res 2011 Aug 14;17(15):5016-25. Epub 2011 Jun 14.

Departments of Craniofacial Biology and Radiation Oncology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO80045, USA.

Purpose: We previously reported that a fibroblast growth factor (FGF) receptor (FGFR) signaling pathway drives growth of lung cancer cell lines of squamous and large cell histologies. Herein, we explored FGFR dependency in cell lines derived from the tobacco-related malignancy, head and neck squamous cell carcinoma (HNSCC).

Experimental Design: FGF and FGFR mRNA and protein expression was assessed in nine HNSCC cell lines. Dependence on secreted FGF2 for cell growth was tested with FP-1039, an FGFR1-Fc fusion protein. FGFR and epidermal growth factor receptor (EGFR) dependence was defined by sensitivity to multiple inhibitors selective for FGFRs or EGFR.

Results: FGF2 was expressed in eight of the nine HNSCC cell lines examined. Also, FGFR2 and FGFR3 were frequently expressed, whereas only two lines expressed FGFR1. FP-1039 inhibited growth of HNSCC cell lines expressing FGF2, identifying FGF2 as an autocrine growth factor. FGFR inhibitors selectively reduced in vitro growth and extracellular signal-regulated kinase signaling in three HNSCC cell lines, whereas three distinct lines exhibited responsiveness to both EGFR and FGFR inhibitors. Combinations of these drugs yielded additive growth inhibition. Finally, three cell lines were highly sensitive to EGFR tyrosine kinase inhibitors (TKI) with no contribution from FGFR pathways.

Conclusions: FGFR signaling was dominant or codominant with EGFR in six HNSCC lines, whereas three lines exhibited little or no role for FGFRs and were highly EGFR dependent. Thus, the HNSCC cell lines can be divided into subsets defined by sensitivity to EGFR and FGFR-specific TKIs. FGFR inhibitors may represent novel therapeutics to deploy alone or in combination with EGFR inhibitors in HNSCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-11-0050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3149730PMC
August 2011

Rapidly acquired resistance to EGFR tyrosine kinase inhibitors in NSCLC cell lines through de-repression of FGFR2 and FGFR3 expression.

PLoS One 2010 Nov 29;5(11):e14117. Epub 2010 Nov 29.

Department of Craniofacial Biology, University of Colorado at Denver, Aurora, Colorado, United States of America.

Despite initial and sometimes dramatic responses of specific NSCLC tumors to EGFR TKIs, nearly all will develop resistance and relapse. Gene expression analysis of NSCLC cell lines treated with the EGFR TKI, gefitinib, revealed increased levels of FGFR2 and FGFR3 mRNA. Analysis of gefitinib action on a larger panel of NSCLC cell lines verified that FGFR2 and FGFR3 expression is increased at the mRNA and protein level in NSCLC cell lines in which the EGFR is dominant for growth signaling, but not in cell lines where EGFR signaling is absent. A luciferase reporter containing 2.5 kilobases of fgfr2 5' flanking sequence was activated after gefitinib treatment, indicating transcriptional regulation as a contributing mechanism controlling increased FGFR2 expression. Induction of FGFR2 and FGFR3 protein as well as fgfr2-luc activity was also observed with Erbitux, an EGFR-specific monoclonal antibody. Moreover, inhibitors of c-Src and MEK stimulated fgfr2-luc activity to a similar degree as gefitinib, suggesting that these pathways may mediate EGFR-dependent repression of FGFR2 and FGFR3. Importantly, our studies demonstrate that EGFR TKI-induced FGFR2 and FGFR3 are capable of mediating FGF2 and FGF7 stimulated ERK activation as well as FGF-stimulated transformed growth in the setting of EGFR TKIs. In conclusion, this study highlights EGFR TKI-induced FGFR2 and FGFR3 signaling as a novel and rapid mechanism of acquired resistance to EGFR TKIs and suggests that treatment of NSCLC patients with combinations of EGFR and FGFR specific TKIs may be a strategy to enhance efficacy of single EGFR inhibitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0014117PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2994708PMC
November 2010

The fibroblast growth factor receptor signaling pathway as a mediator of intrinsic resistance to EGFR-specific tyrosine kinase inhibitors in non-small cell lung cancer.

Drug Resist Updat 2009 Aug-Oct;12(4-5):95-102. Epub 2009 Jun 4.

Department of Medicine, University of Colorado at Denver Anschutz Medical Campus, Aurora, CO 80045, USA.

The EGFR has been targeted through the development of selective tyrosine kinase inhibitors (TKIs) that have proven effective in a subset of non-small cell lung cancer (NSCLC) patients, many bearing gain-of-function EGFR mutations or egfr gene amplification. However, the majority ( approximately 80-90%) of NSCLC patients do not respond to EGFR-specific TKIs and a high rate of acquired resistance to these therapeutics is observed in those that do respond. Thus, EGFR-specific TKIs will not, as single agents, make a high impact on overall lung cancer survival. A number of studies support the activities of other receptor tyrosine kinase pathways including cMet, IGF-1R and FGFRs as mechanisms for both intrinsic and acquired resistance to EGFR TKIs. While the role of cMet and IGF-1R signaling systems as mechanisms of resistance to EGFR TKIs has been widely reviewed in recent years, the potential role of FGFR-dependent signaling as a mechanism for EGFR TKI resistance has more recently emerged and will be highlighted herein. Due to the high degree of homology of FGFRs with VEGFRs and PDGFRs, FGFR-active TKIs already exist via development of VEGFR-targeted TKIs as angiogenesis inhibitors. Thus, these agents could be rapidly advanced into clinical investigations as FGFR inhibitors, either alone or in combination with TKIs selective for EGFR, cMet or IGF-1R as a means to expand the spectrum of NSCLC patients that can be effectively targeted with TKI-directed therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.drup.2009.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763047PMC
March 2010

Fibroblast growth factor (FGF) and FGF receptor-mediated autocrine signaling in non-small-cell lung cancer cells.

Mol Pharmacol 2009 Jan 10;75(1):196-207. Epub 2008 Oct 10.

Department of Craniofacial Biology, University of Colorado at Denver Anschutz Medical Campus, Aurora, CO 80045, USA.

Despite widespread expression of epidermal growth factor (EGF) receptors (EGFRs) and EGF family ligands in non-small-cell lung cancer (NSCLC), EGFR-specific tyrosine kinase inhibitors (TKIs) such as gefitinib exhibit limited activity in this cancer. We propose that autocrine growth signaling pathways distinct from EGFR are active in NSCLC cells. To this end, gene expression profiling revealed frequent coexpression of specific fibroblast growth factors (FGFs) and FGF receptors (FGFRs) in NSCLC cell lines. It is noteworthy that FGF2 and FGF9 as well as FGFR1 IIIc and/or FGFR2 IIIc mRNA and protein are frequently coexpressed in NSCLC cell lines, especially those that are insensitive to gefitinib. Specific silencing of FGF2 reduced anchorage-independent growth of two independent NSCLC cell lines that secrete FGF2 and coexpress FGFR1 IIIc and/or FGFR2 IIIc. Moreover, a TKI [(+/-)-1-(anti-3-hydroxy-cyclopentyl)-3-(4-methoxy-phenyl)-7-phenylamino-3,4-dihydro-1H-pyrimido-[4,5-d]pyrimidin-2-one (RO4383596)] that targets FGFRs inhibited basal FRS2 and extracellular signal-regulated kinase phosphorylation, two measures of FGFR activity, as well as proliferation and anchorage-independent growth of NSCLC cell lines that coexpress FGF2 or FGF9 and FGFRs. By contrast, RO4383596 influenced neither signal transduction nor growth of NSCLC cell lines lacking FGF2, FGF9, FGFR1, or FGFR2 expression. Thus, FGF2, FGF9 and their respective high-affinity FGFRs comprise a growth factor autocrine loop that is active in a subset of gefitinib-insensitive NSCLC cell lines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/mol.108.049544DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2669785PMC
January 2009
-->