title: GABAB receptor complex as a potential target for tumor therapy.
abstract: γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the vertebrate central nervous system. Metabotropic GABA(B) receptors are heterodimeric G-protein-coupled receptors (GPCRs) consisting of GABA(B1) and GABA(B2) subunits. The intracellular C-terminal domains of GABA(B) receptors are involved in heterodimerization, oligomerization, and association with other proteins, which results in a large receptor complex. Multiple splice variants of the GABA(B1) subunit have been identified in which GABA(B1a) and GABA(B1b) are the most abundant isoforms in the nervous system. Isoforms GABA(B1c) through GABA(B1n) are minor isoforms and are detectable only at mRNA levels. Some of the minor isoforms have been detected in peripheral tissues and encode putative soluble proteins with C-terminal truncations. Interestingly, increased expression of GABA(B) receptors has been detected in several human cancer cells and tissues. Moreover, GABA(B) receptor agonist baclofen inhibited tumor growth in rat models. GABA(B) receptor activation not only induces suppressing the proliferation and migration of various human tumor cells but also results in inactivation of CREB (cAMP-responsive element binding protein) and ERK in tumor cells. Their structural complexity makes it possible to disrupt the functions of GABA(B) receptors in various ways, raising GABA(B) receptor diversity as a potential therapeutic target in some human cancers.
authors.affiliation: Sino-France Laboratory for Drug Screening, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China. jiangxn88@mail.hust.edu.cn
authors.forename: Xinnong
authors.initials: X
authors.lastname: Jiang
authors.forename: Li
authors.initials: L
authors.lastname: Su
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Cong
authors.initials: C
authors.lastname: He
authors.forename: Zhongling
authors.initials: Z
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Yi
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002465:Cell Movement; D049109:Cell Proliferation; D019281:Dimerization; D018755:GABA Agonists / Q000494:pharmacology; D006801:Humans; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D051381:Rats; D018080:Receptors, GABA-B / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D018755:GABA Agonists; D018080:Receptors, GABA-B; D001418:Baclofen