Human stromal cells are required for an anti-breast cancer effect of zoledronic acid

Previous studies suggested that bisphosphonate zoledronic acid exerts an antitumor effect by interacting with the microenvironment. In this study, we aimed to elucidate the mechanism behind the anti-breast cancer effect of zoledronic acid.Here we showed that zoledronic acid did not influence in vitro human breast cancer cell survival, but did affect human stromal cell survival. Breast cancer cell death in co-culture with stromal cells was analyzed in vitro by fluorescent microscopy and flowcytometry analysis. In co-culture, the addition of stromal cells to breast cancer cells induced tumor cell death by zoledronic acid, which was abolished by transforming growth factor (TGF)-beta. In the in vivo chicken chorioallantoic membrane model, zoledronic acid reduced the breast cancer cells fraction per tumor only in the presence of human stromal cells. Zoledronic acid decreased TGF-beta excretion by stromal cells and co-cultures. Moreover, supernatant of zoledronic acid treated stromal cells reduced phospho-Smad2 protein levels in breast cancer cells. Thus, zoledronic acid exerts an anti-breast cancer effect via stromal cells, accompanied by decreased stromal TGF-beta excretion and reduced TGF-beta signaling in cancer cells.</p

High hepatocyte growth factor expression in primary tumor predicts better overall survival in male breast cancer

Background Breast cancer is rare in men, but management is focused on tumor characteristics commonly found in female breast cancer. The tumor microenvironment of male breast cancer is less well understood, and insight may improve male breast cancer management. The hepatocyte growth factor (HGF)/c-MET axis and the stromal cell-derived factor-1 (CXCL12)/C-X-C chemokine receptor type 4 (CXCR4) axis are prognostic in women with breast cancer. We aimed to investigate these factors in male breast cancer and correlate them with patient survival. Methods From 841 Dutch males with breast cancer who were enrolled in the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program (NCT01101425) and diagnosed between 1990 and 2010, archival primary tumor samples were collected. Tissue microarrays were constructed with 3 cores per sample and used for immunohistochemical analysis of HGF, c-MET, CXCL12, and CXCR4. Overall survival (OS) of the patients without metastases (M0) was analyzed using the Kaplan-Meier method. The value of the markers regarding OS was determined using univariable and multivariable Cox regression analyses, providing hazard ratios (HRs) and 95% confidence intervals (95% CIs). Results Of 720 out of 841 patients, sufficient tissue was available for analysis; 487 out of 720 patients had M0 disease. Patients with high HGF expression and high CXCL12 expression had a superior OS (low vs high expression of both markers, 7.5 vs 13.0 years, hazard ratio [HR] 0.64, 95% CI 0.49-0.84, P = 0.001 [HGF]; 9.1 vs 15.3 years, HR 0.63, 95% CI 0.45-0.87, P = 0.005 [CXCL12]). Multivariate analysis identified HGF as an independent predictor for OS (HR 0.64, 95% CI 0.47-0.88, P = 0.001). Conclusions HGF and CXCL12 tumor expression appear to identify male breast cancer patients with a relatively good prognosis. Possibly, this could support male breast cancer-specific management strategies in the future

Visualizing dual downregulation of IGF-1R and VEGF by Hsp90 inhibition effect in triple negative breast cancer

Purpose Triple negative breast cancer (TNBC) is biologically characterized by heterogeneous presence of molecular pathways underlying it. Insulin-like growth factor receptor-1 (IGF-1R) expression and vascular endothelial growth factor-A (VEGF-A) have been identified as key factors in these pathways in TNBC. In this study, we aimed at in vivo PET imaging the effect of heat shock protein (Hsp) 90 inhibition by means of NVP-AUY922 on these pathways, with zirconium-89 (89Zr) labeled antibodies targeting IGF-1R and VEGF. Experimental design In vitro NVP-AUY922 effects on cellular IGF-1R expression and VEGF-A secretion were determined in MCF-7 and MDA-MB-231 cell lines. Moreover human TNBC bearing MDA-MB-231 mice received 50 mg/kg NVP-AUY922 or vehicle q3d intraperitoneally for 21 days. PET scans with 89Zr-MAB391 and 89Zr-bevacizumab for visualization of IGF-1R and VEGF were performed before and during treatment. Ex vivo biodistribution and correlative tissue analyses were performed. Results NVP-AUY922 treatment reduced IGF-1R expression and VEGF-A excretion in both cell lines. Hsp90 inhibition lowered tumor uptake on 89Zr-MAB391-PET by 37.3% (P < 0.01) and on 89Zr-bevacizumab-PET by 44.4% (P < 0.01). This was confirmed by ex vivo biodistribution with a reduction of 41.3 % injected dose (ID)/g for 89Zr-MAB391 and 37.8 %ID/g for 89Zr-bevacizumab, while no differences were observed for other tissues. This coincided with reduced IGF-1R expression and mean vessel density in the NVP-AUY922 treated tumors. Conclusion 89Zr-MAB391 and 89Zr-bevacizumab PET reflect effect of Hsp90 inhibitors and can therefore potentially be used to monitor therapeutic effects of Hsp90 inhibitor therapy in TNBC

18F-Fluoroestradiol Tumor Uptake Is Heterogeneous and Influenced by Site of Metastasis in Breast Cancer Patients

Heterogeneity of estrogen receptor (ER) expression in breast cancer is recognized. However, knowledge about varying expression across metastases and surrounding normal tissue in patients is scarce. We therefore analyzed 16α-18F-fluoro-17β-estradiol (18F-FES) PET to assess ER expression heterogeneity. Methods:18F-FES PET on accredited PET/CT camera systems performed in patients with ER-positive metastatic breast cancer November 2009-December 2014 was analyzed. Lesions with an SUVmax 1.5 or more were considered ER-positive, but liver lesions were excluded given high background liver signal. CT lesions with a diameter 10 mm or more were included. We used multilevel linear-mixed models to evaluate determinants of 18F-FES uptake. Cluster analysis was performed with different imaging features per patient as input variables. Results: In 91 patients, 1,617 metastases in bone (78%), lymph node (15%), lung (4%), or liver (2%) were identified by CT (11.2%), PET (56.6%), or both (32.2%). Median tumor uptake varied greatly between patients (SUVmax, 0.54-14.21). 18F-FES uptake in bone metastases was higher than in lymph node and lung metastases (geometric mean SUVmax, 2.61 [95% confidence interval (CI), 2.31-2.94] vs. 2.29 [95% CI, 2.00-2.61; P < 0.001] vs. 2.23 [95% CI, 1.88-2.61; P = 0.021]), respectively. Cluster analysis identified 3 subgroups of patients characterized by particular metastatic sites and 18F-FES PET/CT features. SUVmax in surrounding normal tissue, highest in the bones, varied per patient (range, 0.7-3.3). Conclusion:18F-FES uptake is heterogeneous in tumor and normal tissue and influenced by anatomic site. Different patterns can be distinguished, possibly identifying biologically relevant ER-positive metastatic breast cancer patient subgroups