# Mechanism of evasion by ovarian cancers from anti-VEGF therapy

> **NIH NIH R01** · UNIVERSITY OF TX MD ANDERSON CAN CTR · 2020 · $366,000

## Abstract

PROJECT SUMMARY
The majority of women who are diagnosed with ovarian cancer present with ascites and disseminated disease
and relapse within 18 months after conventional platinum-based chemotherapy. Bevacizumab is a humanized
antibody that was approved in 2014 for treating platinum-resistant recurrent ovarian cancer and has also been
found to increase progression-free survival when combined with conventional chemotherapy as front-line
treatment. Bevacizumab neutralizes vascular endothelial growth factor-A (VEGF), a growth factor that has well-
established roles in stimulating endothelial cell survival, migration and vessel formation and also causes
ascites accumulation. However, not all patients respond to bevacizumab and there are no biomarkers that can
reliably distinguish patients who are likely to benefit from this therapy from those who will not. We have
extensively investigated the mechanisms that control ovarian tumor progression, in particular the interactions
between ovarian cancer cells and constituents of the tumor stroma. Based on our preliminary studies, we
hypothesize that resistance to bevacizumab might stem in part from the ability of ovarian cancer cells to
produce small vesicles called exosomes that act as a `Trojan Horse' to deliver VEGF to endothelial cells
without being neutralized by bevacizumab. In Aim 1 of this project, we will validate the presence of exosomal
VEGF in ovarian cancer patients, determine the signaling mechanism of exosomal VEGF, and evaluate the
ability of exosomal VEGF to stimulate ovarian tumor angiogenesis and ascites formation in xenograft models.
In Aim 2, we will evaluate the ability of bevacizumab to block exosome-induced ovarian tumor angiogenesis
and ascites formation, and evaluate the relationship between levels of exosomal VEGF and responses to
bevacizumab in ovarian cancer xenograft models and ovarian cancer patients. Our study addresses the critical
need for biomarkers that could guide the selection of ovarian cancer patients for whom bevacizumab treatment
is most beneficial and will also provide new insights for designing more effective anti-angiogenic therapies.

## Key facts

- **NIH application ID:** 9956599
- **Project number:** 5R01CA207034-05
- **Recipient organization:** UNIVERSITY OF TX MD ANDERSON CAN CTR
- **Principal Investigator:** Honami Naora
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $366,000
- **Award type:** 5
- **Project period:** 2016-07-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9956599

## Citation

> US National Institutes of Health, RePORTER application 9956599, Mechanism of evasion by ovarian cancers from anti-VEGF therapy (5R01CA207034-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9956599. Licensed CC0.

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