Interaction of uteroglobin with lipocalin-1 receptor suppresses cancer cell motility and invasion.
Cellular migration and invasion are critical for important biological processes including cancer metastasis. We previously reported that uteroglobin (UG), a multifunctional secreted protein, binds to several cell types inhibiting migration and invasion [G.C. Kundu, A.K. Z. Zhang Mandal, G. Mantile-Selvaggi, A.B. Mukherjee (1998) Uteroglobin (UG) suppresses extracellular matrix invasion by normal and cancer cells that express the high affinity UG-binding proteins. J Biol Chem. 273: 22819-22824]. More recently, we reported that HTB-81 adenocarcinoma cells, which do not bind UG, are refractory to UG-mediated inhibition of migration and invasion [Z. Zhang, G.C. Kundu, D. Panda, A.K. Mandal et al. (1999) Loss of transformed phenotype in cancer cells by overexpression of the uteroglobin gene. Proc Natl Acad Sci U S A. 96, 3963-3968]. Since UG shares several biological properties with lipocalin-1 that mediates some of its biological effects via its receptor (Lip-1R), we sought to determine whether UG might interact with Lip-1R and inhibit migration and invasion of HTB-81 cells. To address this question, we first transfected COS-1 cells, which do not bind UG, with a Lip-1R-cDNA construct and performed binding assays using 125I-human UG (hUG). The results show that hUG binds Lip-1R on these cells with high specificity. Further, transfection of HTB-81 cells with the same construct yielded 125I-hUG binding with high affinity (Kd=18 nM) and specificity. The hUG-Lip-1R interaction was further confirmed by transfecting HTB-81, HTB-30 and HTB-174 cells, which are refractory to UG-binding, with a green fluorescent protein (GFP)-Lip-1R-cDNA construct and testing for Lip-1R-hUG colocalization by fluorescence microscopy. Finally, we demonstrate that Lip-1R-hUG interaction on Lip-1R transfected HTB-81 cells renders them fully responsive to hUG-mediated inhibition of migration and invasion. Taken together, these results suggest that Lip-1R is at least one of the UG-binding proteins through which UG exerts anti-motility and anti-invasive effects.
Zhang
Zhongjian
Z
Section on Developmental Genetics, Heritable Disorders Branch, NICHD, NIH, Bethesda, MD 20892-1830, USA.
Kim
Sung-Jo
SJ
Chowdhury
Bhabadeb
B
Wang
Jingya
J
Lee
Yi-Ching
YC
Tsai
Pei-Chih
PC
Choi
Moonsuk
M
Mukherjee
Anil B
AB
D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D017931:DNA Primers; D054835:Lipocalin 1; D008856:Microscopy, Fluorescence; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000378:metabolism*; D014598:Uteroglobin / Q000378:metabolism*
D002352:Carrier Proteins; D017931:DNA Primers; C518443:LCN1 protein, human; D054835:Lipocalin 1; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D014598:Uteroglobin