title: ZD6474 enhances paclitaxel antiproliferative and apoptotic effects in breast carcinoma cells.
abstract: Chemotherapy employing paclitaxel and docetaxel is widely used for treating early-stage breast cancer and metastasis, which is frequently associated with overexpression of epidermal growth factor receptor (EGFR) and resistance to apoptosis. ZD6474, a dual tyrosine kinase inhibitor of EGFR and VEGFR, inhibits cell proliferation of solid tumors, including breast. Phase III clinical trials using ZD6474 in non-small cell lung carcinoma when combined with standard chemotherapy appear promising. In order to improve the antineoplastic activity of paclitaxel, we presently investigated the effects of ZD6474 in combination with paclitaxel in EGFR and VEGFR expressing human breast cancer cell lines MCF-7 and MDA-MB-231. ZD6474 synergistically decreased cell viability when used in combination with paclitaxel. ZD6474 inhibited cyclin D1 and cyclin E expression and induced p53 expression when combined with paclitaxel. The combination of ZD6474 with paclitaxel versus either agent alone also more potently down-regulated the antiapoptotic 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 paclitaxel inhibited anchorage-independent colony formation and invasion of breast cancer cells in vitro as compared to either single agent, indicating a potential involvement of altered expression and reorganization of cytoskeletal proteins in combinatorial treated breast cancer cells. Collectively, our studies indicate that incorporating an anti-EGFR plus VEGFR strategy (ZD6474) with chemotherapy (paclitaxel), where clinical studies of dose-intensive paclitaxel therapy are currently in progress, may be more effective in treating patients with locally advanced or metastatic breast cancer than either approach alone.
authors.affiliation: School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India.
authors.forename: Siddik
authors.initials: S
authors.lastname: Sarkar
authors.forename: Abhijit
authors.initials: A
authors.lastname: Mazumdar
authors.forename: Rupesh
authors.initials: R
authors.lastname: Dash
authors.forename: Devanand
authors.initials: D
authors.lastname: Sarkar
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fisher
authors.forename: Mahitosh
authors.initials: M
authors.lastname: Mandal
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology / Q000627:therapeutic use; D010880:Piperidines / Q000494:pharmacology / Q000627:therapeutic use; D011799:Quinazolines / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D018797:Cell Cycle Proteins; D010880:Piperidines; D011799:Quinazolines; D017239:Paclitaxel; C452423:vandetanib