title: Combined cetuximab and genistein treatment shows additive anti-cancer effect on oral squamous cell carcinoma.
abstract: The purpose of this study was to evaluate the potency of EGFR pathway inhibition achieved by combining cetuximab, an anti-EGFR monoclonal antibody, and genistein, a tyrosine kinase inhibitor, which target extracellular and intracellular domains of the receptor, respectively, in oral squamous cell carcinoma (OSCC) in vitro and in vivo. Two OSCC cell lines, HSC3 and KB, were treated with cetuximab (C, 0-400mug/ml), genistein (G, 0-80muM), or a combination of both at a range of concentrations. Downstream protein expression of EGFR, p-EGFR, and p-Akt were evaluated by Western blot. Cell proliferation and apoptosis indices were calculated to assess anti-cancer effects in vitro. The in vivo effects of cetuximab and genistein on tumor cell growth were examined using an OSCC xenografted nude mouse model and immunohistochemical analyses of proliferation (PCNA) and microvessel density (CD31). Treatment of cells with dual anti-EGFR agents reduced the expressions of p-EGFR, and p-Akt in HSC3 cell line, but there was no significant difference in downregulation between cetuximab alone and in combination with genistein in KB cells. Both HSC3 and KB cells showed a dose-dependent decrease in cell proliferation significantly with single agent treatment and combination (p<0.05). In low concentration, combined cetuximab and genistein therapy resulted in additive growth inhibition and more apoptosis compared to that achieved with single-agent exposure in both cell lines. A combination of cetuximab and genistein significantly inhibited tumor growth and caused a substantial growth delay in in vivo models of both cell lines while each single-agent exposure caused no delay of tumor growth. Immunohistochemical staining with PCNA revealed that the group receiving combined cetuximab and genistein exhibited the lowest number of proliferating cells and microvessel density (p<0.05). Combined therapy with genistein and cetuximab can add the potency of EGFR signaling inhibition. Because not all OSCC cell types appear to respond uniformly, however, selective targeting of distinct molecular pathways is required for effective clinical response.
authors: Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, 28-2 Yun-Gun dong, Seoul, South Korea.
authors: Sung-Jin
authors: SJ
authors: Park
authors: Myung-Jin
authors: MJ
authors: Kim
authors: Yu-Kyoung
authors: YK
authors: Kim
authors: Soung-Min
authors: SM
authors: Kim
authors: Ju-Yong
authors: JY
authors: Park
authors: Hoon
authors: H
authors: Myoung
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000068818:Cetuximab; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D005260:Female; D019833:Genistein / Q000008:administration & dosage*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009062:Mouth Neoplasms / Q000188:drug therapy; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; D019833:Genistein; D066246:ErbB Receptors; D000068818:Cetuximab