Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.

<h4>Objectives</h4>Inhibition of pregnancy-associated plasma protein-A (PAPP-A), an upstream activator of the insulin-like growth factor (IGF) pathway, is known to augment sensitivity to platinum-based chemotherapy. This study further tests the efficacy of PAPP-A inhibition with a monocl...

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Main Authors: Diogo Torres, Xiaonan Hou, Laurie Bale, Ethan P Heinzen, Matthew J Maurer, Valentina Zanfagnin, Ann L Oberg, Cheryl Conover, S John Weroha
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2019-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0224564
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author Diogo Torres
Xiaonan Hou
Laurie Bale
Ethan P Heinzen
Matthew J Maurer
Valentina Zanfagnin
Ann L Oberg
Cheryl Conover
S John Weroha
author_facet Diogo Torres
Xiaonan Hou
Laurie Bale
Ethan P Heinzen
Matthew J Maurer
Valentina Zanfagnin
Ann L Oberg
Cheryl Conover
S John Weroha
author_sort Diogo Torres
collection DOAJ
description <h4>Objectives</h4>Inhibition of pregnancy-associated plasma protein-A (PAPP-A), an upstream activator of the insulin-like growth factor (IGF) pathway, is known to augment sensitivity to platinum-based chemotherapy. This study further tests the efficacy of PAPP-A inhibition with a monoclonal antibody inhibitor (mAb-PA) in ovarian cancer (OC) platinum-resistant patient-derived xenograft (PDX) models.<h4>Methods</h4>PAPP-A expression was quantitated in platinum-resistant PDX models by ELISA. A subset with High (n = 5) and Low (n = 2) expression were revived in female SCID/beige mice for studies with either saline, carboplatin/paclitaxel (CP) + mAb-PA, or CP + IgG2a. The primary endpoint was tumor area by ultrasound on day 28 relative to baseline. Conversion to platinum-sensitive was defined by average tumor regression below baseline. Statistical analyses included linear mixed effects modeling and Kaplan Meier curves. Response to therapy was correlated with changes in the ratio of phosphorylated/total AKT and ERK 1/2 using Wes analysis.<h4>Results</h4>The addition of mAb-PA to CP induced tumor regression below baseline in one High PAPP-A PDX model; another three models exhibited notable growth inhibition relative to CP + IgG2a. None of the Low PAPP-A PDX models regressed below baseline. The PDX model with the greatest magnitude of tumor regression from baseline after combination therapy was maintained on single agent mAb-PA or IgG2a, but no benefit was observed. Decreased phosphorylation of ERK1/2 correlated with conversion to platinum-sensitive.<h4>Conclusions</h4>The addition of mAb-PA to CP overcame platinum-resistance in one of five High PAPP-A PDX models; three other models demonstrated improved platinum-response. This supports further clinical development of this novel therapeutic.
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spelling doaj.art-58adcd9a9c1b4607947f41604fd6ea382022-12-21T23:31:54ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-011411e022456410.1371/journal.pone.0224564Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.Diogo TorresXiaonan HouLaurie BaleEthan P HeinzenMatthew J MaurerValentina ZanfagninAnn L ObergCheryl ConoverS John Weroha<h4>Objectives</h4>Inhibition of pregnancy-associated plasma protein-A (PAPP-A), an upstream activator of the insulin-like growth factor (IGF) pathway, is known to augment sensitivity to platinum-based chemotherapy. This study further tests the efficacy of PAPP-A inhibition with a monoclonal antibody inhibitor (mAb-PA) in ovarian cancer (OC) platinum-resistant patient-derived xenograft (PDX) models.<h4>Methods</h4>PAPP-A expression was quantitated in platinum-resistant PDX models by ELISA. A subset with High (n = 5) and Low (n = 2) expression were revived in female SCID/beige mice for studies with either saline, carboplatin/paclitaxel (CP) + mAb-PA, or CP + IgG2a. The primary endpoint was tumor area by ultrasound on day 28 relative to baseline. Conversion to platinum-sensitive was defined by average tumor regression below baseline. Statistical analyses included linear mixed effects modeling and Kaplan Meier curves. Response to therapy was correlated with changes in the ratio of phosphorylated/total AKT and ERK 1/2 using Wes analysis.<h4>Results</h4>The addition of mAb-PA to CP induced tumor regression below baseline in one High PAPP-A PDX model; another three models exhibited notable growth inhibition relative to CP + IgG2a. None of the Low PAPP-A PDX models regressed below baseline. The PDX model with the greatest magnitude of tumor regression from baseline after combination therapy was maintained on single agent mAb-PA or IgG2a, but no benefit was observed. Decreased phosphorylation of ERK1/2 correlated with conversion to platinum-sensitive.<h4>Conclusions</h4>The addition of mAb-PA to CP overcame platinum-resistance in one of five High PAPP-A PDX models; three other models demonstrated improved platinum-response. This supports further clinical development of this novel therapeutic.https://doi.org/10.1371/journal.pone.0224564
spellingShingle Diogo Torres
Xiaonan Hou
Laurie Bale
Ethan P Heinzen
Matthew J Maurer
Valentina Zanfagnin
Ann L Oberg
Cheryl Conover
S John Weroha
Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.
PLoS ONE
title Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.
title_full Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.
title_fullStr Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.
title_full_unstemmed Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.
title_short Overcoming platinum resistance in ovarian cancer by targeting pregnancy-associated plasma protein-A.
title_sort overcoming platinum resistance in ovarian cancer by targeting pregnancy associated plasma protein a
url https://doi.org/10.1371/journal.pone.0224564
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