BMAL1 Links Bevacizumab Resistance in Colorectal Cancer to Circadian Rhythm and Heme Receptor REVERBA

Abstract

Heme sensor Nuclear Receptor Subfamily 1 Group D Member 1 (NR1D1/REVERBA) and its target gene Aryl Hydrocarbon Receptor Nuclear Translocator-Like (ARNTL/BMAL1) regulate circadian rhythm and angiogenesis. Given their involvement in the interplay between clock disruptions (e.g. by mutations or sleep deprival), cancer risk and vascular biology, we hypothesized that these transcription factors contribute to resistance against anti-angiogenic therapy with vascular endothelial growth factor (VEGFA) neutralizing antibody (bevacizumab, abbrev. Beva) in colorectal cancer (CRC). REVERBA bound to a predicted -672 bp Retinoic Acid Receptor-Related Orphan Receptor Alpha (RORA)-responsive element (RORE) adjacent to a BMAL1 DNA-binding motif (E-box) in the proximal promoter of the human VEGFA gene. REVERBA, indirectly and together with BMAL1, increased VEGFA mRNA and protein expression. Conversely, REVERBA siRNA and REVERBA-antagonist hemin decreased VEGFA synthesis. Beva treatment inhibited CRC growth in a C57BL/6J Apc min/+ genetically modified mouse model (GEMM) and BALB/c nu/nu mouse HCT116 xenografts, without attenuating BMAL1 levels or microvessel density (MVD). In CRC patient tumors (n=74), high BMAL1 protein expression was associated with clinical non-response to combination chemotherapy with Beva (*p=0.0061) and reduced progression-free survival (PFS) [*p=0.0223, Hazard Ratio (HR)=1.69]. In addition, single nucleotide polymorphisms (SNPs) in the BMAL1 (ARNTL) gene correlated with shorter overall survival (OS) [rs11022780, *p=0.014, HR=1.61] and PFS (rs7396943, rs7938307, rs2279287) in patients undergoing combination chemotherapy with Beva. Thus, BMAL1 is associated with Beva resistance in CRC. Since the REVERBA-BMAL1-VEGFA axis can be pharmacologically targeted, interference with this signaling pathway could circumvent resistance to anti-angiogenic therapy in CRC. Funding Statement: This study was supported by grants to EB from the Deutsche Krebshilfe (#108287 and #111086). FE received a fellowship from the “Studienstiftung des deutschen Volkes”. JB was supported by the Translational Physician Scientist (TraPS) Program of the Medical Faculty Mannheim of the Heidelberg University. WW was awarded a fellowship from the Chinese Scholarship Council (#201408080116). ME was supported by the State of Baden-Wurttemberg for “Center of Geriatric Biology and Oncology (ZOBEL) – Perspektivforderung” and “Biology of Frailty - Sonderlinie Medizin”. ATB and ME received funds from the European Commission Seventh Framework Programme (Contract No. 278981 [ANGIOPREDICT]) and are supported by the European Commission Horizon 2020 Programme (Contract No. 754923 [COLOSSUS]). ATB is further supported by Science Foundation Ireland under grant 13/CDA/2183 ”Coloforetell”. HJL was partly funded by the National Cancer Institute (grant number P30CA014089), the Gloria Borges WunderGlo Foundation -The Wunder Project, the Dhont Family Foundation, the San Pedro Peninsula Cancer Guild, the Daniel Butler Research Fund, and the Call to Cure Research Fund Declaration of Interests: The authors declare no conflicts of interest. The reagent mBeva was obtained on the basis of a material transfer agreement (MTA#10082012) from Roche Diagnostics GmbH (Penzberg, Germany). HJL has received clinical trial financial support from Merck Serono and Roche and honoraria for advisory board membership and lectures from Bayer, Boehringer Ingelheim, Genentech, Merck Serono and Roche Ethics Approval Statement: Xenograft studies conformed to the 2010/63/EU guidelines and were approved by the Dept. of Health and Children, Dublin, Ireland (B100/3654) and University College Dublin Animal Research Ethics Committee (P12-27). Therapy studies were conducted in accordance with ethical guidelines (Declaration of Helsinki) and approved by the local ethics committees for each participating site. All patients provided written informed consent for the analysis of molecular correlates.