title: Lenalidomide normalizes tumor vessels in colorectal cancer improving chemotherapy activity.
abstract: Angiogenesis inhibition is a promising approach for treating metastatic colorectal cancer (mCRC). Recent evidences support the seemingly counterintuitive ability of certain antiangiogenic drugs to promote normalization of residual tumor vessels with important clinical implications. Lenalidomide is an oral drug with immune-modulatory and anti-angiogenic activity against selected hematologic malignancies but as yet little is known regarding its effectiveness for solid tumors. The aim of this study was to determine whether lenalidomide can normalize colorectal cancer neo-vessels in vivo, thus reducing tumor hypoxia and improving the benefit of chemotherapy.
  
  
  
  We set up a tumorgraft model with NOD/SCID mice implanted with a patient-derived colorectal cancer liver metastasis. The mice were treated with oral lenalidomide (50 mg/Kg/day for 28 days), intraperitoneal 5-fluorouracil (5FU) (20 mg/Kg twice weekly for 3 weeks), combination (combo) of lenalidomide and 5FU or irrelevant vehicle. We assessed tumor vessel density (CD146), pericyte coverage (NG2; alphaSMA), in vivo perfusion capability of residual vessels (lectin distribution essay), hypoxic areas (HP2-100 Hypoxyprobe) and antitumor activity in vivo and in vitro.
  
  
  
  Treatment with lenalidomide reduced tumor vessel density (p = 0.0001) and enhanced mature pericyte coverage of residual vessels (p = 0.002). Perfusion capability of tumor vessels was enhanced in mice treated with lenalidomide compared to controls (p = 0.004). Accordingly, lenalidomide reduced hypoxic tumor areas (p = 0.002) and enhanced the antitumor activity of 5FU in vivo. The combo treatment delayed tumor growth (p = 0.01) and significantly reduced the Ki67 index (p = 0.0002). Lenalidomide alone did not demonstrate antitumor activity compared to untreated controls in vivo or against 4 different mCRC cell lines in vitro.
  
  
  
  We provide the first evidence of tumor vessel normalization and hypoxia reduction induced by lenalidomide in mCRC in vivo. This effect, seemingly counterintuitive for an antiangiogenic compound, translates into indirect antitumor activity thus enhancing the therapeutic index of chemotherapy. Our findings suggest that further research should be carried out on synergism between lenalidomide and conventional therapies for treating solid tumors that might benefit from tumor vasculature normalization.
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Leuci
authors.affiliation: Laboratory of Transgenic Mouse Models, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Maione
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Rotolo
authors.affiliation: Laboratory of Transgenic Mouse Models, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.|Department of Science and Drug Technology, University of Torino, Turin, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Giraudo
authors.affiliation: Laboratory of Translational Cancer Medicine, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Sassi
authors.affiliation: Laboratory of Translational Cancer Medicine, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Migliardi
authors.affiliation: Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Todorovic
authors.affiliation: Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Gammaitoni
authors.affiliation: Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Mesiano
authors.affiliation: Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Giraudo
authors.affiliation: Laboratory of Cancer Stem Cell Research, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Luraghi
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Division and Laboratory of Medical Oncology, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Leone
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Laboratory of Vascular Oncology, Candiolo Cancer Institute, Candiolo, Turin, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Bussolino
authors.affiliation: Division and Laboratory of Medical Oncology, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Grignani
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Division and Laboratory of Medical Oncology, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Aglietta
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Laboratory of Translational Cancer Medicine, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Trusolino
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy.|Laboratory of Translational Cancer Medicine, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bertotti
authors.affiliation: Department of Oncology, University of Torino, Turin, Italy. dario.sangiolo@ircc.it.|Laboratory of Medical Oncology-Experimental Cell Therapy, Candiolo Cancer Institute-FPO- IRCCS, Candiolo, Turin, Italy. dario.sangiolo@ircc.it.
authors.forename: D
authors.initials: D
authors.lastname: Sangiolo
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000188:drug therapy*; D005472:Fluorouracil / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D000077269:Lenalidomide; D051379:Mice; D016513:Mice, SCID; D009362:Neoplasm Metastasis; D009389:Neovascularization, Pathologic / Q000188:drug therapy* / Q000473:pathology; D010477:Perfusion; D020286:Pericytes / Q000187:drug effects / Q000473:pathology; D013792:Thalidomide / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000072258:Tumor Hypoxia / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D013792:Thalidomide; D000077269:Lenalidomide; D005472:Fluorouracil
keywords: Colorectal cancer; Lenalidomide; Tumor-vessel normalization