title: An in vivo C. elegans model system for screening EGFR-inhibiting anti-cancer drugs.
abstract: The epidermal growth factor receptor (EGFR) is a well-established target for cancer treatment. EGFR tyrosine kinase (TK) inhibitors, such as gefinitib and erlotinib, have been developed as anti-cancer drugs. Although non-small cell lung carcinoma with an activating EGFR mutation, L858R, responds well to gefinitib and erlotinib, tumors with a doubly mutated EGFR, T790M-L858R, acquire resistance to these drugs. The C. elegans EGFR homolog LET-23 and its downstream signaling pathway have been studied extensively to provide insight into regulatory mechanisms conserved from C. elegans to humans. To develop an in vivo screening system for potential cancer drugs targeting specific EGFR mutants, we expressed three LET-23 chimeras in which the TK domain was replaced with either the human wild-type TK domain (LET-23::hEGFR-TK), a TK domain with the L858R mutation (LET-23::hEGFR-TK[L858R]), or a TK domain with the T790M-L858R mutations (LET-23::hEGFR-TK[T790M-L858R]) in C. elegans vulval cells using the let-23 promoter. The wild-type hEGFR-TK chimeric protein rescued the let-23 mutant phenotype, and the activating mutant hEGFR-TK chimeras induced a multivulva (Muv) phenotype in a wild-type C. elegans background. The anti-cancer drugs gefitinib and erlotinib suppressed the Muv phenotype in LET-23::hEGFR-TK[L858R]-expressing transgenic animals, but not in LET-23::hEGFR-TK[T790M-L858R] transgenic animals. As a pilot screen, 8,960 small chemicals were tested for Muv suppression, and AG1478 (an EGFR-TK inhibitor) and U0126 (a MEK inhibitor) were identified as potential inhibitors of EGFR-mediated biological function. In conclusion, transgenic C. elegans expressing chimeric LET-23::hEGFR-TK proteins are a model system that can be used in mutation-specific screens for new anti-cancer drugs.
authors.affiliation: Comparative Biomedicine Research Branch, National Cancer Center, Ilsandong-gu, Goyang-si, Gyeonggi-do, Korea.
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Bae
authors.forename: Jee Young
authors.initials: JY
authors.lastname: Sung
authors.forename: Yong-Nyun
authors.initials: YN
authors.lastname: Kim
authors.forename: Sunshin
authors.initials: S
authors.lastname: Kim
authors.forename: Kyeong Man
authors.initials: KM
authors.lastname: Hong
authors.forename: Heung Tae
authors.initials: HT
authors.lastname: Kim
authors.forename: Min Sung
authors.initials: MS
authors.lastname: Choi
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Kwon
authors.forename: Jaegal
authors.initials: J
authors.lastname: Shim
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002070:Butadienes / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000187:drug effects*; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D023421:Models, Animal; D009154:Mutation; D009369:Neoplasms / Q000188:drug therapy*; D009570:Nitriles / Q000494:pharmacology; D010641:Phenotype; D017434:Protein Structure, Tertiary; D011799:Quinazolines / Q000494:pharmacology; D019076:Transgenes; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D002070:Butadienes; D004791:Enzyme Inhibitors; D009570:Nitriles; D011799:Quinazolines; D020032:Tyrphostins; C113580:U 0126; C101044:RTKI cpd; D066246:ErbB Receptors