Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial.

ABSTRACT: 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).

ORGANISM(S): Homo sapiens

SUBMITTER: Wouter Van Delm

PROVIDER: E-GEOD-60331 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial.

Verstraete M M Debucquoy A A Dekervel J J van Pelt J J Verslype C C Devos E E Chiritescu G G Dumon K K D'Hoore A A Gevaert O O Sagaert X X Van Cutsem E E Haustermans K K

British journal of cancer 20150317 8

<h4>Background</h4>This study characterises molecular effect of bevacizumab, and explores the relation of molecular and genetic markers with response to bevacizumab combined with chemoradiotherapy (CRT).<h4>Methods</h4>From a subset of 59 patients of 84 rectal cancer patients included in a phase II study combining bevacizumab with CRT, tumour and blood samples were collected before and during treatment, offering the possibility to evaluate changes induced by one dose of bevacizumab. We performed ...[more]

PMID: 25867261

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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 α-SMA (pericytes) and CA-IX (hypoxia). To explore candidate blood-based biomarkers ELISA’s 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.

Project description:Importance: Neoadjuvant chemoradiotherapy (CRT) is the standard of care for advanced rectal cancer. Yet, predicting response to CRT remains an unmet clinical challenge. Objective: To investigate the transcriptomic determinants to predict response to neoadjuvant CRT and survival in patients with advanced rectal cancer. Design: A single-center, retrospective, cohort study. Setting: A comprehensive cancer center. Participants: Pre-treatment biopsies from 298 patients with rectal cancer, who were later treated with neoadjuvant CRT between 2004 and 2020, were analyzed by RNA sequencing. Main measures and outcomes: Transcriptional subtyping was performed by consensus molecular subtype (CMS) classification. Immune cell infiltration was assessed using MCP-counter scores and single-sample gene set enrichment analysis (ssGSEA). Patients with surgical specimens of tumor regression grade (TRG) 3-4 or who were managed by the watch-and-wait approach for more than 3 years were defined as good responders. Results: Patients classified as CMS1 (6.4%) had a significantly higher rate of good responders; albeit survival was comparable among the four subtypes. Good responders exhibited an enrichment in various immune-related pathways (IFNg and a responses, allograft rejection, IL6 STAT3 signaling during acute phase response, and inflammation), as determined by ssGSEA. MCP-counter scores for cytotoxic lymphocytes were significantly higher for good responders than non-responders (p = 0.0003), and significantly higher for responders than non-responders in GSE109057 (p = 0.0137), GSE87211 (p = 0.0092), and GSE45404 (p = 0.0327) datasets. Cytotoxic lymphocyte MCP-counter score was thus considered an independent predictor of response to CRT, as determined in the multivariable Cox analysis (OR 3.810 [95% CI 1.820-7.970]; p = 0.0004). Multivariable Cox analysis, including post-operative pathological factors, revealed cytotoxic lymphocyte MCP-counter score to be independently associated with recurrence-free survival (HR 0.382 [95% CI 0.158-0.923]; p = 0.0325) and overall survival (HR 0.157 [95% CI 0.030-0.827]; p = 0.0290). ssGSEA showed significantly higher levels of four subpopulations of cytotoxic cells (effector memory CD8 T, natural killer T, natural killer, and activated CD8 T cells) among good responders than non-responders. Conclusions and Relevance: Cytotoxic lymphocyte score, as computed by RNA sequencing, could be a useful marker for predicting response to CRT and survival among patients with rectal cancer.

Dataset Information

Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial.

Publications

Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial.

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