Raffaella Giavazzi Istituto di Ricerche Faramacologiche MarioNegri VEGF, recettori e sviluppo di inibitori selettivi Roma, 2-3 febbraio 2006 Raffaella Giavazzi Istituto di Ricerche Faramacologiche MarioNegri

Angiogenesis is Required for Sustained Tumor Growth

VEGF (also VEGFA) Related molecules: VEGFB,C,D and placental growth factor Key mediators of angiogenesis MW 45KD Homodimeric glycoprotein Binds VEGFRs,neuropilin1, heparin Four isoform VEGF121 VEGF165 VEGF186 VEGF206

VASCULAR GROWTH FACTORS & THEIR RECEPTORS Yancopoulos et al. Nature 407:242, 2000

Ferrara N et al Nature Reviews Cancer 2003

VEGF: A CENTRAL MEDIATOR OF ANGIOGENESIS Gerber and Ferrara, Cancer Res. 65, 671, 2005

REGULATION OF VEGF IN TUMOR CELLS by: Oncogenes (ras, src, …..) Tumor Supressor Genes (p53, vHippelLindau, PTEN…..) Activated Signaling Pathways (src, Akt/PKB,…..) Transcription Factors (HIF, NF-kB,….). Environmental Factors (hypoxia, low pH,….) Growth Factors/Cytokines & their Receptors (EGFR,IL-1,.. Hormones

VEGF EXPRESSION IS INDUCED BY TUMOR HYPOXIA Hypoxia is a major inducer of VEGF gene expression VEGF mRNA is rapidly induced in the presence of hypoxiain in various cell type VEGF is highly expressed in tumor cells near area of necrosis Importante e il ruolo dell’hypoxia che induce HIF e poi vari geni tra cui VEGF Carmeliet & Jain, Nature 407:249, 2000

VEGF OVEREXPRESSION CAUSES THE FORMATION OF STRUCTURALLY AND FUNCTIONALLY ABNORMAL BLOOD VESSELS Poorly organized, tortuous, hyperpermeable Fewer pericytes Dependent on growth factors for survival and prolifertion Normal Tumor (VEGF) Ani-VEGF Anti-VEGF Adapted from: Jain & Carmeliet, Le Scienze 401:59, 2002

VEGF OVEREXPRESSION Ovary Tumor 1A9 VS1 1A9 VS1 Manenti et al. Mol. Cancer Ther 2005

VEGF IN CANCER DEVELOPMENT AND PROGRESSION Elevated VEGF plasma levels in cancer patients Increased tumor VEGF expression associated with tumor progression and poor prognosis Highly expressed in several tumor types Brain Colon and rectum Lung Breast Kidney Bladder Ovary ---------------

VEGF IN OVARIAN CARCINOMA PATIENTS 10000 100000 1000 10000 100 VEGF pg/ml VEGF pg/ml 10 1000 1 healthy non ovarian malignant carcinoma ascites plasma Manenti et al.. E J Cancer, 2003

VEGF IS A KEY PROANGIOGENIC FACTOR VEGF is a survival factor for newly formed vasculature VEGF is directly implicated in endothelial cell adhesion, proliferation, and migration VEGF is directly involved in proteolytic destruction of the ECM VEGF is directly involved in capillary tube formation VEGF is directly implicated in vascular permeability and vessel maturation Most therapeutic approaches to angiogenesis modulation are focused on endothelial cell functions during blood vessel formation

VEGF & lymphangiogenesis VEGF overexpression leads to lymphatic vessel in exp. tumors Lymphangiogenesis: a route of tumor metastasis stimulated by binding of VEGF-C and D to VEGFR3 promoted by VEGF interaction with VEGFR2

Role of VEGF-C/D in lumphatic metastasis in cancer a, Tumour cells and tumour-associated macrophages secrete lymphangiogenic growth factor VEGF-C or VEGF-D, which induces sprouting of nearby lymphatic vessels, facilitating the access of tumor cells into the vessel lumen. b, Aggregates of tumour cells are transported to the regional lymph node, from which they can spread to distant organs through either blood or lymphatic vessels. Blockage of VEGFR-3 signalling inhibits metastasis in most mouse tumour xenograft models by stabilizing lymphatic vessels. c, Nude mice were implanted with luciferase-tagged tumour cells, which metastasize to the ipsilateral axillary lymph node d, By contrast, metastasis was abolished in mice treated with adenovirus encoding a VEGF-C/D trap75. Alitalo et al.Nature 2005

Lymphangiogenesis & Metastasis Tumor lymphangiogenesis: A novel prognostic indicator for cutaneous melanoma metastasis and survival. Dadraset SS. al. Am J Path 162:1951, 2003

OTHERS VEGF FUNCTIONS VEGF is implicated in intraocular neovascularization (diabetes mellitus,….age-related macular degeneration, AMD) Role of VEGF in motoneurone degeneration (amytropic lateral sclerosis, ALS)

TARGETING VEGF IN CACER

VEGF INHIBITORS UNDER INVESTIGATION

RECEPTOR TARGETING AGENTS 5 100 150 1E-09 SU 5416 (M) HUVEC HOC 1E-08 1E-07 1E-06 1E-05 1E-04 % Proliferation 100 200 300 400 500 10 20 30 40 50 Days after tumor transplant Tumor weight (mg) DC101 Vascuar index = 18 Vehicle Vascular Index = 45

NEUTRALIZING ANTI-VEGF MOMOCLONAL ANTIBODY

POTENTIAL EFFECTS OF INHIBITING VEGF Prevention of the growth of new tumor blood vessels suppression of primary and metastatic tumor growth Regression of tumor vasculature and restoration of vascular permeability and intratumoral pressure improved access for other anticancer agents (and O2) Vascular regression possible tumor dormancy From : Jain RK. Nat Med 2001; Willett CG, et al. Nat Med 2004

TO CLINICAL TRIALS ….