Project description:Objective: Insights about differences in tumor vasculature and how it reacts to VEGF inhibition is limited, but nevertheless of major relevance to anti-angiogenic therapy. In this study we therefore characterize the effect of bevacizumab combined with chemoradiotherapy (CRT), and explore molecular and genetic markers for response prediction to this combination treatment. Material and Methods: In an academic multicentric randomized phase II study, patients with advanced rectal cancer have been treated with bevacizumab (5mg/kg) in combination with capecitabine (1650mg/m2/day) and radiotherapy (45Gy; 1.8Gy/day) with (50mg/m2) or without oxaliplatin prior to surgery. Of 59 patients, tumor tissue and blood samples were collected before treatment and after the first loading dose of bevacizumab but before CRT (week 3). First, cDNA micro-arrays were performed on the biopsies to investigate differences in gene expression of tumors from patients with and without a pathological complete response (pCR) before start of treatment and to identify biological processes affected by bevacizumab delivery. The paraffin embedded tissue was stained for blood vessels (CD31/CD34) combined with Î±-SMA (pericytes) and CA-IX (hypoxia). To explore candidate blood-based biomarkers ELISAâs were performed for PDGF-AA, PDGF-BB, THBS-1, IL-8, CYR61 and Ang-2. The expression of all markers was correlated with the pathological response of the patients. Results: Differences in tumoral gene expression are observed between patients with and without a pCR, with the first response group presenting a more angiogenic phenotype before start of treatment and changes in angiogenic processes after bevacizumab delivery. One dose of bevacizumab leads to a decrease in the number of pericyte covered blood vessels, a decrease in circulating PDGF-AA, PDGF-BB and Thrombospondin-1. Patients showing a pCR having less pericyte covered blood vessels, more hypoxia, and less circulating PDGF-BB compared to patients who did not have a pCR after bevacizumab treatment with chemoradiation and bevacizumab. Conclusions: The translational data demonstrate that tumors with an angiogenic expression profile respond better to bevacizumab combined with CRT and points towards a possible role for PDGF, CA-IX and pericyte covered blood vessels for the early response prediction to this treatment. Our findings suggest a role for mural cell recruitment and vessel maturation for the susceptibility of the tumor vasculature to bevacizumab treatment. Further validation of our biological observations and hypothesis generating data in randomized trials is needed. This study involves samples of patients enrolled in the AXEbeam trail that were analysed by Primeview microarray (Affymetrix). Biopsies were taken at two different timepoints: before treatment (tumor and normal mucosa) and after the first loading dose of bevacizumab but before chemoradiation (only tumor, week 3). Patients were classified into two groups: with a complete pathological response at time of surgery (Responders=R) or non-responders (NR). For the responders, we collected 21 samples in total (7 tumor samples and 8 normal mucosa samples taken before treatment and 6 tumor samples collected at week 3). From the non-responders we had 26 samples in total (9 tumor and 10 mucosa samples before treatment and 7 tumor samples at week 3 after a single dose of bevacizumab). Microarrays were run in two batches (15xxx versus 16xxx CEL file samples; indicated in the description field). Three samples (NJ 04/003 T1, RVS 09/002 M and NJ 04/003 W3) were put twice on the array (15897+16789; 15893+16790; 15898+16791) to verify and exclude batch effects. Please note that, due to these three technical repeats the total number of microarray CEL files is 50 (21 Responders, 26 Non-responders and 3 repeats).

Project description:The VEGF targeted antiangiogenic drug bevacizumab has shown varying results in clinical trials of breast cancer. Identifying robust biomarkers for selecting patients that may benefit from bevacizumab treatment and for monitoring of response is important for the future use of this drug. Two established xenograft models representing basal-like and luminal-like breast cancer were used to study bevacizumab treatment response on the metabolic and gene expression levels. Mice given no treatment or treated with bevacizumab, doxorubicin or the combination of these two drugs were sacrificed at day 3 or 10. High resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS) and gene expression microarray analysis was performed on all tumor samples. Combination treatment with bevacizumab had the strongest growth inhibiting effect in the basal-like tumors, and this was reflected in a significant response in the metabolomic and transcriptomic profiles. In the luminal-like xenografts, addition of bevacizumab did not improve the effect of doxorubicin. On the global transcriptomic level, the largest changes in gene expression were observed for the most efficient treatment in each of the two xenograft models. The metabolite glycerophosphocholine (GPC) showed opposite response in the treated xenografts compared with untreated controls: lower in basal-like tumors and higher in luminal-like tumors. Lower levels of creatine, taurine and glycine were observed in the basal-like xenografts given bevacizumab as monotherapy compared with untreated xenografts. Comparing combination therapy with doxorubicin monotherapy in basal-like xenografts, 14 genes showed significant differential expression, including higher expression of very low density lipoprotein receptor (VLDLR), and lower expression of hemoglobin, theta 1 (HBQ1). Using published gene expression signatures, bevacizumab treated tumors were associated with a more hypoxic phenotype, while no evidence was found for associations between bevacizumab treatment and vascular invasion or increasing tumor grade. This study underlines the importance of characterizing biological differences between subtypes of breast cancer to identify personalized biomarkers for selecting patients for bevacizumab treatment and evaluating response to therapy.

Project description:The VEGF targeted antiangiogenic drug bevacizumab has shown varying results in clinical trials of breast cancer. Identifying robust biomarkers for selecting patients that may benefit from bevacizumab treatment and for monitoring of response is important for the future use of this drug. Two established xenograft models representing basal-like and luminal-like breast cancer were used to study bevacizumab treatment response on the metabolic and gene expression levels. Mice given no treatment or treated with bevacizumab, doxorubicin or the combination of these two drugs were sacrificed at day 3 or 10. High resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS) and gene expression microarray analysis was performed on all tumor samples. Combination treatment with bevacizumab had the strongest growth inhibiting effect in the basal-like tumors, and this was reflected in a significant response in the metabolomic and transcriptomic profiles. In the luminal-like xenografts, addition of bevacizumab did not improve the effect of doxorubicin. On the global transcriptomic level, the largest changes in gene expression were observed for the most efficient treatment in each of the two xenograft models. The metabolite glycerophosphocholine (GPC) showed opposite response in the treated xenografts compared with untreated controls: lower in basal-like tumors and higher in luminal-like tumors. Lower levels of creatine, taurine and glycine were observed in the basal-like xenografts given bevacizumab as monotherapy compared with untreated xenografts. Comparing combination therapy with doxorubicin monotherapy in basal-like xenografts, 14 genes showed significant differential expression, including higher expression of very low density lipoprotein receptor (VLDLR), and lower expression of hemoglobin, theta 1 (HBQ1). Using published gene expression signatures, bevacizumab treated tumors were associated with a more hypoxic phenotype, while no evidence was found for associations between bevacizumab treatment and vascular invasion or increasing tumor grade. This study underlines the importance of characterizing biological differences between subtypes of breast cancer to identify personalized biomarkers for selecting patients for bevacizumab treatment and evaluating response to therapy. 60 samples are analyzed. For each of the two xenograft models, tumors were collected from animals that were untreated or treated with bevacizumab (5 mg/kg), doxorubicin (8 mg/kg) or a combination of the two therapies (n = 6 tumors for each group). Bevacizumab treatment was repeated at day 4 and day 7. Animals were sacrificed and tissue harvested at either day 3 or 10 after treatment, in triplicates within each treatment group. This resulted in 24 tumor samples from each of the models. In addition, untreated and bevacizumab treated luminal-like xenografts not fed with estradiol were included for comparison (n = 12). Note that the untreated controls are overlapping with the samples in the GEO series with accession number: GSE25915.

Project description:Background. Bevacizumab, an antibody neutralizing Vascular Endothelial Growth Factor (VEGF), is licensed for the management of patients with advanced colon cancer. However, tumor biomarkers identifying the molecular tumor subsets most amenable to angiogenesis modulation are lacking. Patients and Methods. We profiled expession of 24526 genes by means of whole genome 24K DASL (c-DNA-mediated, Annealing, Selection and Ligation) arrays, (Illumina, CA) in 16 bevacizumab-treated patients with advanced colon cancer (Test set). Genes with correlation to 8-month Progression-free status were studied by means of qPCR in two independent colon cancer cohorts: 49 patients treated with bevacizumab+chemotherapy (Bevacizumab qPCR set) and 72 patients treated with chemotherapy only (Control qPCR set). Endpoints were best tumor response before metastasectomy (ORR) and progression-free survival (PFS). Results. Five genes were significantly correlated to 8-month progression-free status in the Test set: overexpression of KLF12 and downregulation of AGR2, ALDH6A1, MCM5, TFF2. In the two independent datasets, irinotecan- or oxaliplatin-based chemotherapy was administered as first-line treatment and metastasectomies were subsequently applied in 8-14% of patients. No prognostically significant gene classifier encompassing all five genes could be validated in the Bevacizumab or Control qPCR sets. The complex gene expression profile of all-low tumor (ALDH6A1+TFF2+MCM5) was strongly associated with ORR in the Bevacizumab qPCR set (ORR 85.7%, p=0.007), but not in the Control set (ORR 36.4%, p=0.747). The Odds Ratio for response for the all-low tumor (ALDH6A1+TFF2+MCM5) profile versus any other ALDH6A1+TFF2+MCM5 profile was 15 (p=0.018) in the Bevacizumab qPCR set but only 0.72 (p=0.63) in the Control set. The tumor expression profile of (KLF12-high+TFF2-low) was significantly associated with PFS only in the Bevacizumab qPCR set: bevacizumab-treated patients with (KLF12-high + TFF2-low) tumors had superior PFS (median 14 months, 95% CI 2-21) compared to patients with any other (KLF12+TFF2) expression profile (median PFS 7 months, 95% CI 5-10, p=0.021). The Hazard Ratio for disease progression for (KLF12-high + TFF2-low) versus any other KLF12+TFF2 expression profile was 2.92 (p=0.03) in the Validation and 1.29 (p=0.39) in the Control set. Conclusions. Our <three-stage> hypothesis-generating study failed to validate the prognostic significance of a five-gene classifier in mCRC patients. Exploratory analyses suggest two gene signatures that are potentially associated with bevazicumab benefit in patients with advanced colon cancer. 18 tumor tissue samples were analysed, no replicates

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Immuno-priming with bevacizumab: durvalumab plus bevacizumab after prolonged exposition to bevacizumab in breast cancer

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