Cathleen R Carlin

Case Western Reserve University, Cleveland, Ohio, United States

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Publications (74)457.8 Total impact


  • No preview · Article · Nov 2015 · Neuro-Oncology

  • No preview · Article · Aug 2015 · Cancer Research
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    ABSTRACT: Numerous studies by our lab and others demonstrate that epidermal growth factor receptor (EGFR) plays critical roles in primary breast cancer (BC) initiation, growth and dissemination. However, clinical trials targeting EGFR function in BC have lead to disappointing results. In the current study we sought to identify the mechanisms responsible for this disparity by investigating the function of EGFR across the continuum of the metastatic cascade. We previously established that overexpression of EGFR is sufficient for formation of in situ primary tumors by otherwise nontransformed murine mammary gland cells. Induction of epithelial-mesenchymal transition (EMT) is sufficient to drive the metastasis of these EGFR-transformed tumors. Examining growth factor receptor expression across this and other models revealed a potent downregulation of EGFR through metastatic progression. Consistent with diminution of EGFR following EMT and metastasis EGF stimulation changes from a proliferative to an apoptotic response in in situ versus metastatic tumor cells, respectively. Furthermore, overexpression of EGFR in metastatic MDA-MB-231 BC cells promoted their antitumorigenic response to EGF in three dimensional (3D) metastatic outgrowth assays. In line with the paradoxical function of EGFR through EMT and metastasis we demonstrate that the EGFR inhibitory molecule, Mitogen Induced Gene-6 (Mig6), is tumor suppressive in in situ tumor cells. However, Mig6 expression is absolutely required for prevention of apoptosis and ultimate metastasis of MDA-MB-231 cells. Further understanding of the paradoxical function of EGFR between primary and metastatic tumors will be essential for application of its targeted molecular therapies in BC.
    Preview · Article · Jan 2015 · Neoplasia (New York, N.Y.)
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    ABSTRACT: Antiangiogenic therapy shows great promise for treatment of cancer. Bevacizumab is a humanized mAb that blocks VEGF-A, thereby inhibiting angiogenesis. It has received FDA approval for patients with recurrent glioblastoma (GBM); however, approximately 30% of patients are non-responsive and the underlying mechanism for the lack of response is not known. It has been assumed that Bevacizumab solely targets circulating VEGF-A; however, VEGF-A found in the perivascular space of GBM tumors could also be an important target. We hypothesized that Bevacizumab is transcytosed across brain endothelial cells (ECs), gains access to the perivascular niche containing glioma stem cells (GSCs), and that differences in GSC endocytosis and targeting of Bevacizumab for recycling or degradation determines a patients' response. We found that Bevacizumab is internalized by normal and tumor-isolated brain ECs in a time-dependent manner that is partially inhibited by amiloride and stimulated by EGF, suggesting Bevacizumab enters the cells by macropinocytosis. ECs transcytose 62% of Bevacizumab over two-hours. Importantly, we found that 95% of GSCs internalize Bevacizumab in 30 minutes. Internalized Bevacizumab in GSCs can be recycled to the extracellular space or degraded; at 5 minutes we found that Bevacizumab was localized to the Rab4+ fast recycling compartment (67%); whereas at 30 minutes only 7% localized to the Rab4+ compartment and 16% localized to the LAMP1+ compartment (late endosome/lysosome). Furthermore, in an orthotopic xenograft mouse model of GBM administered Bevacizumab, we found a gradient of Bevacizumab extending from the vessel into the tumor and it was readily detected within perivascular tumor cells. Our data indicate that the trafficking of Bevacizumab by perivascular GSCs in GBM may influence Bevacizumab effectiveness in patients. Understanding the mechanism of internalization and trafficking of Bevacizumab in GSCs from different molecular subtypes of GBM may help us understand which patients will be responsive to Bevacizumab therapy.
    Full-text · Article · Nov 2014 · Neuro-Oncology

  • No preview · Article · Oct 2014 · Cancer Research
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    ABSTRACT: Cellular programs coupled to cycles of epithelial-mesenchymal transitions (EMTs) play critical roles during embryogenesis, as well as during tissue development, remodeling, and repair. Research over the last decade has established the importance of an ever-expanding list of master EMT transcription factors, whose activity is regulated by STAT3 and function to stimulate the rapid transition of cells between epithelial and mesenchymal phenotypes. Importantly, inappropriate reactivation of embryonic EMT programs in carcinoma cells underlies their metastasis to distant organ sites, as well as their acquisition of stem cell-like and chemoresistant phenotypes operant in eliciting disease recurrence. Thus, targeted inactivation of master EMT transcription factors may offer new inroads to alleviate metastatic disease. Here we review the molecular, cellular, and microenvironmental factors that contribute to the pathophysiological activities of STAT3 during its regulation of EMT programs in human carcinomas.
    Preview · Article · Apr 2014
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    ABSTRACT: Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
    Full-text · Dataset · Dec 2013
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    ABSTRACT: Toxoplasma gondii resides in an intracellular compartment (parasitophorous vacuole) that excludes transmembrane molecules required for endosome - lysosome recruitment. Thus, the parasite survives by avoiding lysosomal degradation. However, autophagy can re-route the parasitophorous vacuole to the lysosomes and cause parasite killing. This raises the possibility that T. gondii may deploy a strategy to prevent autophagic targeting to maintain the non-fusogenic nature of the vacuole. We report that T. gondii activated EGFR in endothelial cells, retinal pigment epithelial cells and microglia. Blockade of EGFR or its downstream molecule, Akt, caused targeting of the parasite by LC3(+) structures, vacuole-lysosomal fusion, lysosomal degradation and killing of the parasite that were dependent on the autophagy proteins Atg7 and Beclin 1. Disassembly of GPCR or inhibition of metalloproteinases did not prevent EGFR-Akt activation. T. gondii micronemal proteins (MICs) containing EGF domains (EGF-MICs; MIC3 and MIC6) appeared to promote EGFR activation. Parasites defective in EGF-MICs (MIC1 ko, deficient in MIC1 and secretion of MIC6; MIC3 ko, deficient in MIC3; and MIC1-3 ko, deficient in MIC1, MIC3 and secretion of MIC6) caused impaired EGFR-Akt activation and recombinant EGF-MICs (MIC3 and MIC6) caused EGFR-Akt activation. In cells treated with autophagy stimulators (CD154, rapamycin) EGFR signaling inhibited LC3 accumulation around the parasite. Moreover, increased LC3 accumulation and parasite killing were noted in CD154-activated cells infected with MIC1-3 ko parasites. Finally, recombinant MIC3 and MIC6 inhibited parasite killing triggered by CD154 particularly against MIC1-3 ko parasites. Thus, our findings identified EGFR activation as a strategy used by T. gondii to maintain the non-fusogenic nature of the parasitophorous vacuole and suggest that EGF-MICs have a novel role in affecting signaling in host cells to promote parasite survival.
    Full-text · Article · Dec 2013 · PLoS Pathogens
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    ABSTRACT: Niemann-Pick disease type C (NPC) is caused by mutations in NPC1 or NPC2, which coordinate egress of LDL-cholesterol from late endosomes (LEs). We previously reported that the adenovirus-encoded protein RIDα rescues the cholesterol storage phenotype in NPC1-mutant fibroblasts. We show here that RIDα reconstitutes deficient endosome-to-endoplasmic reticulum (ER) transport allowing excess LDL-cholesterol to be esterified by acyl-CoA cholesterol acyl transferase and stored in lipid droplets (LDs) in NPC1-deficient cells. Furthermore, the RIDα pathway is regulated by the oxysterol-binding protein ORP1L. Studies to date have classified ORP1L as a sterol sensor involved in LE positioning downstream of GTP-Rab7, however our data suggest ORP1L may play a role in the transport of LDL-cholesterol to a specific ER pool designated for LD formation. In contrast to NPC1 which is dispensable, the RIDα/ORP1L dependent route requires functional NPC2. Although NPC1/NPC2 constitutes the major pathway, therapies that amplify minor egress routes for LDL-cholesterol could significantly improve clinical management of patients with loss-of-function NPC1 mutations. The molecular identity of putative alternative pathways however is poorly characterized. We propose RIDα as a model system for understanding physiological egress routes that utilize ORP1L to activate ER feedback responses involved in LD formation.
    Preview · Article · Sep 2013 · Molecular biology of the cell
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    Full-text · Dataset · Sep 2013

  • No preview · Article · Aug 2013 · Cancer Research
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    ABSTRACT: We previously established that overexpression of the EGF receptor (EGFR) is sufficient to induce tumor formation by otherwise non-transformed mammary epithelial cells, and that the initiation of epithelial-mesenchymal transition (EMT) is capable of increasing the invasion and metastasis of these cells. Using this breast cancer (BC) model, we find that in addition to EGF, adhesion to fibronectin (FN) activates Signal Transducer and Activator of Transcription 3 (Stat3) through EGFR-dependent and -independent mechanisms. Importantly, EMT facilitated a signaling switch from Src-dependent EGFR:Stat3 signaling in pre-EMT cells to EGFR-independent FN:Jak2:Stat3 signaling in their post-EMT counterparts, thereby sensitizing these cells to Jak2 inhibition. Accordingly, human metastatic BC cells that failed to activate Stat3 downstream of EGFR did display robust Stat3 activity upon adhesion to FN. Furthermore, FN enhanced outgrowth in three-dimensional organotypic cultures via a mechanism that is dependent upon β1 integrin, Janus kinase 2 (Jak2), and Stat3 but not EGFR. Collectively, our data demonstrate that matrix-initiated signaling is sufficient to drive Stat3 activation, a reaction that is facilitated by EMT during BC metastatic progression.
    No preview · Article · May 2013 · Journal of Biological Chemistry
  • M. K. Wendt · N. Balanis · C. Carlin · W. Schiemann

    No preview · Article · Mar 2013 · Clinical Cancer Research

  • No preview · Article · Feb 2013 · Cancer Research
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    Xuehuo Zeng · Cathleen R Carlin
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    ABSTRACT: Human adenoviruses typically cause mild infections in the upper or lower respiratory tract, gastrointestinal tract, or ocular epithelium. However adenoviruses may be life-threatening in patients with impaired immunity and some serotypes cause epidemic outbreaks. Attachment to host cell receptors activates cell signaling and virus uptake by endocytosis. At present it is unclear how vital cellular homeostatic mechanisms affect these early steps in the adenovirus life cycle. Autophagy is a lysosomal degradation pathway for recycling intracellular components that is up-regulated during periods of cell stress. Autophagic cargo are sequestered in double-membrane structures called autophagosomes that fuse with endosomes to form amphisomes which then deliver their content to lysosomes. Autophagy is an important adaptive response in airway epithelial cells targeted by many common adenovirus serotypes. Using two established tissue culture models, we demonstrate here that adaptive autophagy enhances expression of the early region 1 adenovirus protein, induction of mitogen-activated protein kinase signaling, and production of new viral progeny in airway epithelial cells infected with adenovirus type 2. We have also discovered that adenovirus infections are tightly regulated by endosome maturation, a process characterized by abrupt exchange of Rab5 and Rab7 GTPases associated with early and late endosomes, respectively. Moreover endosome maturation appears to control a pool of early endosomes capable of fusing with autophagosomes which enhance adenovirus infection. Many viruses have evolved mechanisms to induce autophagy in order to aid their own replication. Our studies reveal a novel role for host cell autophagy that could have a significant impact on the outcome of respiratory infections.
    Preview · Article · Dec 2012 · Journal of Virology
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    Calvin U Cotton · Michael E Hobert · Sean Ryan · Cathleen R Carlin
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    ABSTRACT: Proliferation of epithelial tissues is controlled by polarized distribution of signaling receptors including the EGF receptor (EGFR). In kidney, EGFRs are segregated from soluble ligands present in apical fluid of nephrons by selective targeting to basolateral membranes. We have shown previously that the epithelial-specific clathrin adaptor AP1B mediates basolateral EGFR sorting in established epithelia. Here we show that protein kinase C (PKC)-dependent phosphorylation of Thr654 regulates EGFR polarity as epithelial cells form new cell-cell junctional complexes. The AP1B-dependent pathway does not override a PKC-resistant T654A mutation, and conversely AP1B-defective EGFRs sort basolaterally by a PKC-dependent mechanism, in polarizing cells. Surprisingly, EGFR mutations that interfere with these different sorting pathways also produce very distinct phenotypes in three-dimensional organotypic cultures. Thus EGFRs execute different functions depending on the basolateral sorting route. Many renal disorders have defects in cell polarity and the notion that apically mislocalized EGFRs promote proliferation is still an attractive model to explain many aspects of polycystic kidney disease. Our data suggest EGFR also integrates various aspects of polarity by switching between different BL sorting programs in developing epithelial cells. Fundamental knowledge of basic mechanisms governing EGFR sorting therefore provides new insights into pathogenesis and advances drug discovery for these renal disorders.
    Full-text · Article · Dec 2012 · Traffic
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    Full-text · Dataset · Nov 2012
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    ABSTRACT: Protein tyrosine phosphatase nonreceptor type 14 (PTPN14) is frequently mutated in a variety of human cancers. However, the cell signaling pathways regulated by PTPN14 largely remain to be elucidated. Here, we identify a list of potential substrates of PTPN14 using a phospho-proteomic approach. We show that p130 Crk-associated substrate (p130Cas) is a direct substrate of PTPN14 and that PTPN14 specifically regulates p130Cas phosphorylation at tyrosine residue 128 (Y128) in colorectal cancer (CRC) cells. We engineered CRC cells homozygous for a p130Cas Y128F knock-in mutant and found that these cells exhibit significantly reduced migration and colony formation, impaired anchorage-independent growth, slower xenograft tumor growth in nude mice and have decreased phosphorylation of AKT. Furthermore, we demonstrate that SRC phosphorylates p130Cas Y128 and that CRC cell lines harboring high levels of pY128Cas are more sensitive to SRC family kinase inhibitor Dasatinib. These findings suggest that p130Cas Y128 phosphorylation may be exploited as a predictive marker for Dasatinib response in cancer patients. In aggregate, our studies reveal a novel signaling pathway that has an important role in colorectal tumorigenesis.Oncogene advance online publication, 18 June 2012; doi:10.1038/onc.2012.220.
    Full-text · Article · Jun 2012 · Oncogene
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    ABSTRACT: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
    Full-text · Article · Apr 2012 · Autophagy
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
    Full-text · Article · Apr 2012 · Autophagy

Publication Stats

3k Citations
457.80 Total Impact Points

Institutions

  • 1992-2015
    • Case Western Reserve University
      • • Department of Molecular Biology and Microbiology
      • • Case Comprehensive Cancer Center
      • • Department of Physiology and Biophysics
      • • School of Medicine
      Cleveland, Ohio, United States
    • Washington University in St. Louis
      • Department of Molecular Microbiology
      San Luis, Missouri, United States
  • 2012
    • University of Michigan
      • Life Sciences Institute
      Ann Arbor, MI, United States
  • 1982-1994
    • Wistar Institute
      Philadelphia, Pennsylvania, United States
    • University of North Carolina at Chapel Hill
      North Carolina, United States
  • 1990
    • St Louis University Hospital
      • Institute for Molecular Virology
      San Luis, Missouri, United States
  • 1989
    • University of Missouri - St. Louis
      Сент-Луис, Michigan, United States