Cancer-associated fibroblasts regulate endothelial adhesion protein LPP to promote ovarian cancer chemoresistance
Cecilia S. Leung, … , Michael J. Birrer, Samuel C. Mok
Cecilia S. Leung, … , Michael J. Birrer, Samuel C. Mok
Published December 18, 2017
Citation Information: J Clin Invest. 2018;128(2):589-606. https://doi.org/10.1172/JCI95200.
View: Text | PDF
Research Article Cell biology Oncology

Cancer-associated fibroblasts regulate endothelial adhesion protein LPP to promote ovarian cancer chemoresistance

Abstract

The molecular mechanism by which cancer-associated fibroblasts (CAFs) confer chemoresistance in ovarian cancer is poorly understood. The purpose of the present study was to evaluate the roles of CAFs in modulating tumor vasculature, chemoresistance, and disease progression. Here, we found that CAFs upregulated the lipoma-preferred partner (LPP) gene in microvascular endothelial cells (MECs) and that LPP expression levels in intratumoral MECs correlated with survival and chemoresistance in patients with ovarian cancer. Mechanistically, LPP increased focal adhesion and stress fiber formation to promote endothelial cell motility and permeability. siRNA-mediated LPP silencing in ovarian tumor–bearing mice improved paclitaxel delivery to cancer cells by decreasing intratumoral microvessel leakiness. Further studies showed that CAFs regulate endothelial LPP via a calcium-dependent signaling pathway involving microfibrillar-associated protein 5 (MFAP5), focal adhesion kinase (FAK), ERK, and LPP. Thus, our findings suggest that targeting endothelial LPP enhances the efficacy of chemotherapy in ovarian cancer. Our data highlight the importance of CAF–endothelial cell crosstalk signaling in cancer chemoresistance and demonstrate the improved efficacy of using LPP-targeting siRNA in combination with cytotoxic drugs.

Authors

Cecilia S. Leung, Tsz-Lun Yeung, Kay-Pong Yip, Kwong-Kwok Wong, Samuel Y. Ho, Lingegowda S. Mangala, Anil K. Sood, Gabriel Lopez-Berestein, Jianting Sheng, Stephen T.C. Wong, Michael J. Birrer, Samuel C. Mok

×

Figure 4

CAF-derived MFAP5 upregulates endothelial LPP expression and promotes angiogenesis in vivo.

Options: View larger image (or click on image) Download as PowerPoint
CAF-derived MFAP5 upregulates endothelial LPP expression and promotes an...
(A) Micrographs showing that recMFAP5-containing Matrigel plugs implanted i.p. into mice had significantly more CD31-positive endothelial cells than did PBS-containing Matrigel implants. Matrigel reconstituted with basic FGF (bFGF), a known proangiogenic protein, was used as a positive control. Scale bars: 100 μm. (B) Box and whisker plots showing the effect of recMFAP5 on total tube length, total tube area, and segment and node numbers in Matrigel plugs reconstituted with recMFAP5. The phenotypes of the endothelial cell networks in the Matrigel implants were analyzed using MetaMorph software. Compared with that reconstituted with PBS, the Matrigel reconstituted with recMFAP5 had significantly longer total tube lengths, larger total tube areas, more segments, and more nodes. The boxes in the box plot represent the interquartile range, and the lines across the boxes indicate the median. The whiskers indicate the highest and lowest values that were no greater than 1.5 times the interquartile range (n = 10/group; P values were determined by Mann-Whitney U test). (C) Heatmap showing differentially expressed genes that were up- or downregulated in endothelial cells isolated from recMFAP5-containing Matrigel implants compared with cells from PBS-containing Matrigel implants in mice. Transcriptome profiling of endothelial cells isolated from Matrigel implants revealed that 394 genes were expressed at significantly higher levels and 449 genes were expressed at significantly lower levels in recMFAP5-containing Matrigel implants compared with cells from PBS-containing Matrigel implants (P < 0.05, by moderated t test and Benjamini-Hochberg multiple testing correction). Expression of Lpp was increased by 2-fold in endothelial cells isolated from recMFAP5-containing Matrigel implants compared with cells from PBS-containing Matrigel implants. (D) qRT-PCR analyses showing that endothelial cells isolated from recMFAP5-containing Matrigel implants had significantly higher levels of Lpp mRNA than did PBS-containing Matrigel implants (mean ± SEM of 3 independent experiments; 2-tailed Student’s t test). (E) Hematoxylin-counterstained micrographs showing that endothelial cells from recMFAP5-containing Matrigel implants had markedly higher Lpp protein levels than did cells from PBS-containing Matrigel implants. Scale bars: 10 μm.