--- This page is part of [Coy Laboratory Products](https://www.coylab.com). For a complete overview of this site's content, entity data, and subject matter expertise, see our [AI Content Index](https://www.coylab.com/llms.txt) or [Full Content Archive](https://www.coylab.com/llms-full.txt). For structured business identity data, see our [Entity Card](https://www.coylab.com/wp-json/bc-geodesic/v1/entity-card). --- # Hypoxia-inducible Factor-1-dependent Regulation of the Multidrug Resistance ( MDR1) Gene > Abstract The microenvironment of rapidly growing tumors is associated with increased energy demand and diminished vascular supply, resulting in focal areas... **URL:** https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/ **Type:** Citation **Modified:** 2025-10-02 --- #### Abstract The microenvironment of rapidly growing tumors is associated with increased energy demand and diminished vascular supply, resulting in focal areas of prominent hypoxia. A number of hypoxia-responsive genes have been associated with growing tumors, and here we demonstrate that the multidrug resistance (MDR1) gene product P-glycoprotein, a Mr 170,000 transmembrane protein associated with tumor resistance to chemotherapeutics, is induced by ambient hypoxia. Initial studies using quantitative microarray analysis of RNA revealed an 7-fold increase in MDR in epithelial cells exposed to hypoxia (pO2 20 torr, 18 h). These findings were further confirmed at the mRNA and protein level. P-Glycoprotein function was studied by analysis of verapamil-inhibitable efflux of digoxin and rhodamine 123 in intact T84 cells and revealed that hypoxia enhances P-glycoprotein function by as much as 7 0.4-fold over normoxia. Subsequent studies confirmed hypoxia-elicited MDR1 gene induction and increased P-glycoprotein expression in nontransformed, primary cultures of human microvascular endothelial cells, and analysis of multicellular spheroids subjected to hypoxia revealed increased resistance to doxorubicin. Examination of the MDR1 gene identified a binding site for hypoxia inducible factor-1 (HIF-1), and inhibition of HIF-1 expression by antisense oligonucleotides resulted in significant inhibition of hypoxia-inducible MDR1 expression and a nearly complete loss of basal MDR1 expression. Studies using luciferase promoter constructs revealed a significant increase in activity in cells subjected to hypoxia, and such hypoxia inducibility was lost in truncated constructs lacking the HIF-1 site and in HIF-1 binding site mutants. Extensions of these studies also identified a role for Sp1 in this hypoxia response. Taken together, these data indicate that the MDR1 gene is hypoxia responsive, and such results may identify hypoxia-elicited P-glycoprotein expression as a pathway for resistance of some tumors to chemotherapeutics. ## Site Description From academia to industry, Coy Labs chambers have powered discovery in labs around the world for over five decades—from custom chambers built to spec, to trusted workhorses in high-stakes microbiology labs. --- **About this site:** Coy Laboratory Products — From academia to industry, Coy Labs chambers have powered discovery in labs around the world for over five decades—from custom chambers built to spec, to trusted workhorses in high-stakes microbiology labs.. [AI Content Index](https://www.coylab.com/llms.txt) | [Full Site Content](https://www.coylab.com/llms-full.txt) | [Entity Card](https://www.coylab.com/wp-json/bc-geodesic/v1/entity-card) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://www.coylab.com/#organization","name":"Coy Laboratory Products","url":"https://www.coylab.com","description":"From academia to industry, Coy Labs chambers have powered discovery in labs around the world for over five decades—from custom chambers built to spec, to trusted workhorses in high-stakes microbiology labs.","disambiguatingDescription":"Laboratory equipment manufacturing company specializing in vinyl glove boxes","logo":{"@type":"ImageObject","url":"https://coylab.com/wp-content/uploads/2025/06/coylab-header_logo-svg.svg"},"address":{"@type":"PostalAddress","streetAddress":"14500 Coy Drive","addressLocality":"Grass Lake","addressRegion":"MI","postalCode":"49240"},"telephone":"734.475.2200","email":"sales@coylab.com","foundingDate":"1969","areaServed":"Global","sameAs":["https://www.linkedin.com/company/107172311","https://maps.app.goo.gl/o2txKDMScV1pV7w59","https://www.pharmaceutical-tech.com/suppliers/coy-laboratory","https://craft.co/coy-laboratory-products-inc"],"founder":[{"@type":"Person","name":"Richard Coy"},{"@type":"Person","name":"Brian Coy","sameAs":"https://www.linkedin.com/in/brian-coy-5722515/"},{"@type":"Person","name":"Ashley Coy","sameAs":"https://www.linkedin.com/in/ashley-coy-6b22705/"}],"knowsAbout":[{"@type":"Thing","name":"laboratory equipment","sameAs":"https://www.wikidata.org/wiki/Q834028"},"vinyl anaerobic chambers","vinyl hypoxic chambers","laboratory glove boxes","laboratory chamber sensors",{"@type":"Thing","name":"life sciences","sameAs":"https://www.wikidata.org/wiki/Q864928"},{"@type":"Thing","name":"microbiology","sameAs":"https://www.wikidata.org/wiki/Q7193"},{"@type":"Thing","name":"medical research","sameAs":"https://www.wikidata.org/wiki/Q2752427"}]},{"@type":"WebSite","@id":"https://www.coylab.com/#website","name":"Coy Laboratory Products","url":"https://www.coylab.com","publisher":{"@id":"https://www.coylab.com/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://www.coylab.com/?s={search_term_string}"},"query-input":"required name=search_term_string"},"hasPart":[{"@type":"DigitalDocument","name":"LLM Content Index","url":"https://www.coylab.com/llms.txt","encodingFormat":"text/markdown","description":"AI-readable index of site content, entity data, and subject matter expertise"},{"@type":"DigitalDocument","name":"LLM Full Content","url":"https://www.coylab.com/llms-full.txt","encodingFormat":"text/markdown","description":"Complete AI-readable site content"}]},{"@type":"ItemList","@id":"https://www.coylab.com/#site-navigation","name":"Site Navigation","itemListElement":[{"@type":"SiteNavigationElement","position":1,"name":"Products","url":"#"},{"@type":"SiteNavigationElement","position":2,"name":"Applications","url":"#"},{"@type":"SiteNavigationElement","position":3,"name":"Custom","url":"#"},{"@type":"SiteNavigationElement","position":4,"name":"Sales","url":"#"},{"@type":"SiteNavigationElement","position":5,"name":"Resources","url":"#"},{"@type":"SiteNavigationElement","position":6,"name":"Contact Us","url":"#"}]},{"@type":"BreadcrumbList","@id":"https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://www.coylab.com"},{"@type":"ListItem","position":2,"name":"Citations","item":"https://www.coylab.com/research-citations/"},{"@type":"ListItem","position":3,"name":"Hypoxic Chambers","item":"https://www.coylab.com/citation-category/hypoxic-chambers/"},{"@type":"ListItem","position":4,"name":"Hypoxia-inducible Factor-1-dependent Regulation of the Multidrug Resistance ( MDR1) Gene"}]},{"@type":"WebPage","@id":"https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/#webpage","url":"https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/","name":"Hypoxia-inducible Factor-1-dependent Regulation of the Multidrug Resistance ( MDR1) Gene | Coy Laboratory Products","isPartOf":{"@id":"https://www.coylab.com/#website"},"breadcrumb":{"@id":"https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/#breadcrumb"},"description":"Scientists around the world have relied on Coy chambers to conduct groundbreaking research into cancer growth, the human microbiome, c-diff., and more.","about":[{"@type":"Thing","name":"Hypoxic Chambers"}]},{"@type":"ScholarlyArticle","@id":"https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/#scholarlyarticle","headline":"Hypoxia-inducible Factor-1-dependent Regulation of the Multidrug Resistance ( MDR1) Gene","url":"https://www.coylab.com/research-citation/hypoxia-inducible-factor-1-dependent-regulation-of-the-multidrug-resistance-mdr1-gene/","datePublished":"2025-09-18T15:50:06+00:00","dateModified":"2025-10-02T20:22:08+00:00","isPartOf":{"@id":"https://www.coylab.com/#website"},"description":"Scientists around the world have relied on Coy chambers to conduct groundbreaking research into cancer growth, the human microbiome, c-diff., and more.","author":{"@id":"https://www.coylab.com/author/buildcreate/#person"},"publisher":{"@id":"https://www.coylab.com/#organization"}},{"@type":"Person","@id":"https://www.coylab.com/author/buildcreate/#person","name":"buildcreate","url":"https://www.coylab.com/author/buildcreate/"}]} ```