IONIZING RADIATION IN ANGIOGENESIS AND TUMOR METASTASIS

Ionizing radiation treatment is delivered in a fractionated plan, consisting of daily small doses.

WHAT IS KNOWN? Tumor-associated host cells (Endothelial Cells, leukocytes, macrophages, fibrobasts, myofibroblasts) Tumor cells The effects of ionizing radiation in the tumor area

Robust tumor growth requires the presence of a local vascular network that supplies both oxygen and nutrients to tumor cells.

Angiogenesis… Angeion : vessel genesis: formation anti-angiogenic factors The Angiogenic Balance pro-angiogenic factors

RADIOTHERAPY AND TUMOR VOLUME EXPECTED EFFECT IN TUMOR CELLS DNA damage; p53-mediated apoptosis; mitotic cell death; senescence-like irreversible growth arrest; apoptosis UNEXPECTED EFFECTS IN TUMOR CELLS Tumor growing within a previously irradiated bed tends to be more invasive and to form more metastasis – TUMOR BED EFFECT (Milas L et al. Int J Radiat Oncol Biol Phys 1997;13:379-83) (Milas L et al. Cancer Res 1988;48: ) (Vicini FA et al. Cancer 2003;97:910-9) (Suit HD et al. Int J Radiat Oncol Biol Phys 1992;23:653-60) (O’Brien CJ et al. Am J Surg 1986;152:456-63) (Vikram B. et al. Head Neck Surg 1984;6:730-3) Clinically: Tumor recidives within a preirradiated field are associated with higher risk of metastasis and poor prognosis

Cancer Cell bFGF HIF-1 VEGF Ak t NO eNOS Towards Target Cell ROS VEGF 5-40 Gy IL-10 IL-4 IL-3 IR induces the production of pro-angiogenic molecules by the tumors… (McBride WH et al. Radiat Res 2004;162:1-19) (Moeller BJ et al. Cell Cycle 2004;3: ) (Gupta, VK et al. Cancer J 2002;8:47-54) (Gorski, DH et al. Cancer Res 1999;59: )

Endothelial Cell Sonveaux P Gupta, V.K CerSM ASMase AKT MAPK PLC PI3K VEGFR2bFGFR Cer SM ASMase MAPK FAK PLC PI3K Actin VEGFR2bFGFR VEGF bFGF Migration Adhesion Proliferation Hydrolysis Survival Apoptosis Kolesnick and Fucks, 2003 Gulbins and Kolesnick, 2003 eNOS Cancer Cell AKT ROS AP-1 …that may activate endothelial cells inducing a pro-angiogenic response MAPK RAF V3V3 …that may activate endothelial cells inducing a pro-angiogenic response

Cancer Res 2008;68: Nature Reviews Cancer 2008; 8: HIF Ionizing Radiation “Upregulation of HIF-1activity promotes tumor and endothelial cell survival.” “CYR61 and  V  5 are molecules that cooperate to promote metastasis. This work suggests a therapeutic approach for preventing escape, which can be promptly tested in the clinic.”

RADIOTHERAPY AND TUMOR VOLUME EXPECTED EFFECT IN TUMOR CELLS RADIOTHERAPY SUCESS UNEXPECTED EFFECTS Tumor cells Endothelial cells IR THE KNOWLEDGE OF THE MECHANISMS INVOLVED IN THE UNEXPECTED EFFECTS OF IR NOVEL THERAPEUTIC APPROACHES COMBINED WITH RADIOTHERAPY RADIORESISTANCE

What are the biological effects of LD of IR in the tissues surrounding the high dose area?

Do low doses of IR have pro- angiogenic effects in the vasculature that surrounds the tumoral area? In collaboration with: Serviço de Radiotherapia (HSM, Portugal)

Therapeutic doses Tumor area response Doses lower than the therapeutic Vasculature response of the tissues that surround the tumor TUMOR RECIDIVE AND METASTASIS AFTER RADIOTHERAPY In collaboration with: Serviço de Radiotherapia (HSM, Portugal) ON Pro-angiogenic factors Anti-angiogenic factors

ON Pro-angiogenic factors Anti-angiogenic factors Gy VEGFR-2 Lung Human microvascular endothelial cells Vala et al., Plos One 2010 Jun 21;5(6):e11222 Low-dose IR might disrupt the balance

Vala et al., Plos One 2010 Jun 21;5(6):e11222 Low dise IR accelerates angiognic sprouting during zebrafish embryonic development and enhances angiogenesis during zebrafish fin regeneration

Vala et al., Plos One 2010 Jun 21;5(6):e11222 Low-dose IR promotes acceleration of tumor growth in a VEGF receptor-dependent manner

Vala et al., Plos One 2010 Jun 21;5(6):e11222 Low-dose IR promotes metastasis in a VEGF receptor-dependent manner

OUR SCIENTIFIC CONTRIBUTION …. Clinically relevant element to the interpretation of dosimetry in radiotherapy Identifying the pro-angiogenic effects that low-dose IR might have on the vasculature surrounding the tumoral mass

Susana Constantino, PhD Raquel Sampaio, PhD Augusto Ministro, MD Inês Vala Inês Domingues Filipa Cunha André Rocha ANGIOGENESIS UNIT, IMM Curzio Ruegg (University of Lausanne, Switzerland) Marc Mareel (University Hospital Ghent, Belgium) Leonard Zon (Harvard Medical School, USA) Radiotherapy Service, HSM, Portugal (Prof. Drª. Isabel M. Grillo) Collaborators: