title: Targeted therapy against EGFR and VEGFR using ZD6474 enhances the therapeutic potential of UV-B phototherapy in breast cancer cells.
abstract: BACKGROUND
  The hypoxic environment of tumor region stimulated the up regulation of growth factors responsible for angiogenesis and tumor proliferation. Thus, targeting the tumor vasculature along with the proliferation by dual tyrosine kinase inhibitor may be the efficient way of treating advanced breast cancers, which can be further enhanced by combining with radiotherapy. However, the effectiveness of radiotherapy may be severely compromised by toxicities and tumor resistance due to radiation-induced adaptive response contributing to recurrence and metastases of breast cancer. The rational of using ZD6474 is to evaluate the feasibility and efficacy of combined VEGFR2 and EGFR targeting with concurrent targeted and localized UV-B phototherapy in vitro breast cancer cells with the anticipation to cure skin lesions infiltrated with breast cancer cells.
  
  
  METHODS
  Breast cancer cells were exposed to UV-B and ZD6474 and the cell viability, apoptosis, invasion and motility studies were conducted for the combinatorial effect. Graphs and statistical analyses were performed using Graph Pad Prism 5.0.
  
  
  RESULTS
  ZD6474 and UV-B decreased cell viability in breast cancers in combinatorial manner without affecting the normal human mammary epithelial cells. ZD6474 inhibited cyclin E expression and induced p53 expression when combined with UV-B. It activated stress induced mitochondrial pathway by inducing translocation of bax and cytochrome-c. The combination of ZD6474 with UV-B vs. either agent alone also more potently down-regulated the anti-apoptotic bcl-2 protein, up-regulated pro-apoptotic signaling events involving expression of bax, activation of caspase-3 and caspase-7 proteins, and induced poly (ADP-ribose) polymerase resulting in apoptosis. ZD6474 combined with UV-B inhibited invasion of breast cancer cells in vitro as compared to either single agent, indicating a potential involvement of pro-angiogenic growth factors in regulating the altered expression and reorganization of cytoskeletal proteins in combinatorial treated breast cancer cells. Involvement of combination therapy in reducing the expression of matrix metalloprotease was also observed.
  
  
  CONCLUSIONS
  Collectively, our studies indicate that incorporating an anti-EGFR plus VEGFR strategy (ZD6474) with phototherapy (UV-B), an alternative approach to the ongoing conventional radiotherapy for the treatment of infiltrating metastatic breast cancer cells in the skin and for locally recurrence breast cancer than either approach alone.
authors.forename: Siddik
authors.initials: S
authors.lastname: Sarkar
authors.forename: Shashi
authors.initials: S
authors.lastname: Rajput
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Tripathi
authors.affiliation: School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302, West Bengal, India. mahitosh@smst.iitkgp.ernet.in.
authors.forename: Mahitosh
authors.initials: M
authors.lastname: Mandal
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D001943:Breast Neoplasms / Q000628:therapy*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects / Q000528:radiation effects; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003131:Combined Modality Therapy; D003599:Cytoskeleton / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000528:radiation effects; D058990:Molecular Targeted Therapy; D010789:Phototherapy; D010880:Piperidines / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D014466:Ultraviolet Rays; D014467:Ultraviolet Therapy; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D010880:Piperidines; D011799:Quinazolines; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C512478:EGFR protein, human; D066246:ErbB Receptors; C000588866:KDR protein, human; D040301:Vascular Endothelial Growth Factor Receptor-2; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053148:Caspase 3; D053179:Caspase 7; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; C452423:vandetanib