Losartan treatment enhances chemotherapy efficacy and reduces ascites in ovarian cancer models by normalizing the tumor stroma

Proc Natl Acad Sci U S A. 2019 Feb 5;116(6):2210-2219. doi: 10.1073/pnas.1818357116. Epub 2019 Jan 18.


In ovarian cancer patients, tumor fibrosis and angiotensin-driven fibrogenic signaling have been shown to inversely correlate with survival. We sought to enhance drug delivery and therapeutic efficacy by remodeling the dense extracellular matrix in two orthotopic human ovarian carcinoma xenograft models. We hypothesized that targeting the angiotensin signaling axis with losartan, an approved angiotensin system inhibitor, could reduce extracellular matrix content and the associated "solid stress," leading to better anticancer therapeutic effect. We report here four translatable findings: (i) losartan treatment enhances the efficacy of paclitaxel-a drug used for ovarian cancer treatment-via normalizing the tumor microenvironment, resulting in improved vessel perfusion and drug delivery; (ii) losartan depletes matrix via inducing antifibrotic miRNAs that should be tested as candidate biomarkers of response or resistance to chemotherapy; (iii) although losartan therapy alone does not reduce tumor burden, it reduces both the incidence and the amount of ascites formed; and (iv) our retrospective analysis revealed that patients receiving angiotensin system inhibitors concurrently with standard treatment for ovarian cancer exhibited 30 mo longer overall survival compared with patients on other antihypertensives. Our findings provide the rationale and supporting data for a clinical trial on combined losartan and chemotherapy in ovarian cancer patients.

Keywords: angiotensin inhibition; antifibrotic miRNAs; ascites; drug delivery; ovarian cancer.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Ascites / drug therapy
  • Ascites / pathology*
  • Collagen / genetics
  • Collagen / metabolism
  • Disease Models, Animal
  • Drug Synergism
  • Extracellular Matrix / metabolism
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Hypoxia / metabolism
  • Losartan / pharmacology*
  • Mice
  • MicroRNAs / genetics
  • Models, Theoretical
  • Neoplasm Staging
  • Neovascularization, Pathologic / drug therapy
  • Neovascularization, Pathologic / metabolism
  • Ovarian Neoplasms / drug therapy
  • Ovarian Neoplasms / metabolism*
  • Ovarian Neoplasms / mortality
  • Ovarian Neoplasms / pathology*
  • Prognosis
  • Stress, Physiological / drug effects
  • Stromal Cells / drug effects
  • Stromal Cells / metabolism
  • Stromal Cells / pathology*
  • Treatment Outcome
  • Tumor Microenvironment / drug effects
  • Xenograft Model Antitumor Assays


  • Antineoplastic Agents
  • MicroRNAs
  • Collagen
  • Losartan