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Principal Investigator: Ozgur Sahin
Organization: MEDICAL UNIVERSITY OF SOUTH CAROLINA
Fiscal Year: 2024
Award: $352,295
Funding agency: National Cancer Institute
PROJECT SUMMARY
Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype. It accounts for ~15% of
all breast cancer patients yet is responsible for 30% of breast cancer deaths. TNBC is treated primarily by
conventional chemotherapy; however, resistance to therapy is common leading to high mortality rates.
Recently, we identified hypoxia-induced ECM re-modeler, lysyl oxidase (LOX) as a key mediator of
doxorubicin resistance in TNBC (Saatci et al, Nature Communications, 2020). LOX inhibition offers a unique
opportunity to re-sensitize the most aggressive breast tumors to standard-of-care chemotherapeutics. The
overall objectives of this project are to (i) delineate the roles of LOX in chemoresistance, (ii) determine the
mechanisms through which LOX exerts these roles, (iii) and generate prototypes of potent and selective LOX
inhibitors to overcome chemoresistance in TNBC. We hypothesize that (i) LOX induces resistance not only
to doxorubicin but also to other chemotherapeutic drugs by its enzymatic activity; (ii) LOX exerts this effect
both by increasing collagen cross-linking/fibronectin assembly (canonical LOX function) leading to reduced
drug penetration and increased integrin-mediated signaling and by regulating transcription (non-canonical
LOX function) via interacting and oxidizing its substrates, culminating in activation of FAK/Src signaling and
cell survival; and (iii) targeting LOX activity with selective small-molecule inhibitors will overcome
chemoresistance by blocking both canonical and non-canonical LOX functions in TNBC. These hypotheses
will be tested by pursuing three specific aims: 1) To determine the role of canonical ECM cross-linking function
of LOX in resistance to different chemotherapeutics in TNBC. We will test the general chemosensitizer role
of LOX and necessity of its enzymatic activity by generating cells with CRISPR-mediated LOX knock-out and
reconstitution and testing their effects on chemoresistance in vitro and in vivo. LOX-mediated ECM changes
will be analyzed by advanced microscopy techniques, e.g. MP-SHG, and the resulting drug penetration will
be studied by IF and MALDI-MSI. 2) To determine the role of non-canonical transcription-regulating functions
of LOX in TNBC chemoresistance. We will determine if LOX controls global transcription and identify novel
LOX substrates by combining transcriptomics (RNA-Seq) and proteomics (TurboID) approaches. We will
generate oxidation-deficient LOX substrates and test their effects on LOX-mediated chemoresistance. 3) To
characterize novel LOX enzymatic inhibitors and test their potential as chemosensitizers in TNBC. We will
test the selectivity of our inhibitors in cells with LOX knock-out/reconstitution and their off-target profiles and
test their chemosensitization ability in organoids. We will perform PK/PD and toxicity profiling studies and
test the inhibitors for overcoming chemoresistance in TNBC PDXs. The proposed project is expected to
provide key mechanistic and phenotypic pre-clinical data to show that targeting LOX will overcome
chemoresistance in the most aggressive breast cancer subtype, with a potential to reduce mortality rates.
Terms: <14-Hydroxydaunomycin><3-D><3-Dimensional><3D><3D cell culture><3D culture><Adriamycine><Apoptosis><Apoptosis Pathway><Assay><Binding><Bioassay><Biological Assay><Breast><Breast Cancer><Breast Cancer Cell><Breast Cancer Model><Breast Cancer Patient><Breast Cancer cell line><Breast Neoplasms><Breast PDX models><Breast Tumor Patient><Breast Tumors><Breast tumor cell line><Breast tumor model><CD49e Antigens><CRISPR><CRISPR approach><CRISPR based approach><CRISPR method><CRISPR methodology><CRISPR technique><CRISPR technology><CRISPR tools><CRISPR-CAS-9><CRISPR-based method><CRISPR-based technique><CRISPR-based technology><CRISPR-based tool><CRISPR/CAS approach><CRISPR/Cas method><CRISPR/Cas system><CRISPR/Cas technology><CRISPR/Cas9><CRISPR/Cas9 technology><Cas nuclease technology><Cell Body><Cell Communication and Signaling><Cell Signaling><Cell Survival><Cell Viability><Cell-Extracellular Matrix><Cells><Cessation of life><Chemoresistance><Chemosensitization><Chemosensitization/Potentiation><Clustered Regularly Interspaced Short Palindromic Repeats><Clustered Regularly Interspaced Short Palindromic Repeats approach><Clustered Regularly Interspaced Short Palindromic Repeats method><Clustered Regularly Interspaced Short Palindromic Repeats methodology><Clustered Regularly Interspaced Short Palindromic Repeats technique><Clustered Regularly Interspaced Short Palindromic Repeats technology><Cold-Insoluble Globulins><Collagen><Collagen Lysyl Oxidase><Communication><Cryosectioning><Cryoultramicrotomy><DNA><DNA Damage><DNA Injury><Data><Death><Death Rate><Deoxyribonucleic Acid><Dose><Doxorubicin><Doxorubicina><Drug Kinetics><Drug Therapy><Drugs><EC 1.4.3.13><ECM><Experimental Models><Extracellular Matrix><FADK><FAK><FAK1><FN1><FNRA><Fibronectin 1><Fibronectin Receptor Alpha Subunit><Fibronectins><Gene Transcription><Generations><Genes><Genetic Transcription><Goals><HIF 1 alpha><HIF-1alpha><HIF1-Alpha><HIF1A><HIF1A gene><HIF1α><Hydroxyl Daunorubicin><Hydroxyldaunorubicin><Hypoxia><Hypoxic><ITGA5><ITGA5 gene><Immunoblotting><Immunofluorescence><Immunofluorescence Immunologic><Immunohistochemistry><Immunohistochemistry Cell/Tissue><Immunohistochemistry Staining Method><In Vitro><Induction of Apoptosis><Integrin Alpha 5><Integrin alpha5><Integrin alphaF><Integrin α5><Integrins><Integrins Extracellular Matrix><Intracellular Communication and Signaling><Knock-out><Knockout><LETS Proteins><LOXL2><LOXL2 gene><Large External Transformation-Sensitive Protein><Lysyl Oxidase><Lysyl Oxidase-Like 2><MALD-MS><MALDI><MALDI-MS><MDR Modulators><MOP1><Malignant Breast Neoplasm><Mammary Cancer><Mammary Neoplasms><Maximal Tolerated Dose><Maximally Tolerated Dose><Maximum Tolerated Dose><Measures><Mediating><Mediator><Medication><Methods><Microscopy><Mission><Molecular Interaction><Multidrug Resistance Modifier><Multidrug Resistance Modulator><Multidrug-Resistance Antagonists><Multidrug-Resistance Chemo Sensitizers><Multidrug-Resistance Inhibitors><NIH><National Institutes of Health><Nature><Nuclear><Opsonic Glycoprotein><Opsonic alpha(2)SB Glycoprotein><Organoids><Output><Oxygen Deficiency><PDX model><PK/PD><PTK2><PTK2 gene><Paper><Pathway interactions><Patient derived xenograft><Patient-derived xenograft models of breast cancer><Penetration><Pharmaceutical Preparations><Pharmacodynamics><Pharmacokinetics><Pharmacotherapy><Phenotype><Physiologic><Physiological><Platelet Glycoprotein Ic><Potentiation><Programmed Cell Death><Protein-Lysine 6-Oxidase><Proteins><Proteomics><Public Health><RNA Expression><RNA Seq><RNA sequencing><RNAseq><Refractory><Relapse><Resistance><Role><Signal Transduction><Signal Transduction Systems><Signaling><Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization><Spectroscopy, Mass, Matrix-Assisted Laser Desorption-Ionization><Structure-Activity Relationship><System><TNBC><Techniques><Testing><Therapeutic><Toxic effect><Toxicities><Transcription><Transcription Regulation><Transcriptional Control><Transcriptional Regulation><United States National Institutes of Health><VLA-5 alpha Chain><VLA5A><Western Blotting><Western Immunoblotting><aggressive breast cancer><alpha 2-Surface Binding Glycoprotein><alpha(5) Integrin><biological signal transduction><breast cancer PDX><breast cancer patient-derived xenograft><breast tumor cell><cancer sub-types><cancer subtypes><chemical structure function><chemopotentiating agent><chemoresistant><chemosensitizer><chemosensitizing agent><chemotherapy><chemotherapy resistance><chemotherapy resistant><clinical relevance><clinically relevant><crosslink><disability><drug treatment><drug/agent><experiment><experimental research><experimental study><experiments><in vivo><in vivo Model><inhibitor><mRNA Expression><malignant breast tumor><mammary cancer model><mammary tumor><mammary tumor model><matrix assisted laser desorption ionization><mortality rate><mortality ratio><multi-photon><mutant><novel><overexpress><overexpression><oxidation><paralog><paralogous gene><pathway><patient derived xenograft model><patient subclass><patient subcluster><patient subgroups><patient subpopulations><patient subsets><patient subtypes><pharmacokinetics and pharmacodynamics><pp125FAK><pre-clinical><preclinical><protein blotting><protein expression><prototype><reconstitute><reconstitution><resistance to therapy><resistant><resistant to therapy><screening><screenings><second harmonic><small molecular inhibitor><small molecule><small molecule inhibitor><social role><standard of care><structure function relationship><success><therapeutic resistance><therapy resistant><three dimensional><three dimensional cell culture><trafficking><transcriptome sequencing><transcriptomic sequencing><transcriptomics><treatment resistance><triple-negative breast cancer><triple-negative invasive breast carcinoma><tumor><tumor xenograft>