ABSTRACT
BACKGROUND:As a novel growth factor, human intestinal trefoil factor (TFF3) can promote cel growth and migration, and increase cel resistance to apoptosis, and it plays a great role in maintaining the mucosa integrity, mucosa protection and repairing the injured mucosa, also it has been closely related to the tumor growth and progression. With the function of mucosa repair, and as the tumor biomarker, TFF3 has a promising clinical application, but its definite interacting protein and molecular mechanism is stil unclear. OBJECTIVE:To construct and express the TFF3 recombinant protein with the tandem tag of StrepII-6×His in the target cel s for further purifying its interaction protein in the native condition based on the tandem affinity purification technique. METHODS:The DNA sequence for the tag (StrepII-TEV-6×His) and TFF3 as template was got by chemical synthesis and PCR amplification respectively. They were fused by the restriction enzyme XbaI site, and the tag sequence was located at the C terminus of TFF3 protein. TFF3-tag fusion gene was cloned into the pCDNA3.0 using EcoRI+HindIII, thus the TFF3-tag expressing vector pTFF3-C-StH was constructed and transfected transiently into gastric cel AGS by lipofectin. The recombinant TFF3-tag protein was expressed and detected by western blot assay. RESULTS AND CONCLUSION:The expressing vector pTFF3-C-StH for tandem affinity purification was constructed successful y, and was confirmed further by restriction enzyme analysis and sequenced. The recombinant TFF3-C-StH protein of TFF3-tag was expressed in the AGS cel , and showed specific antigenicity by western blot assay. Thus this work provides experimental base for further purification of the TFF3 interacting proteins.
ABSTRACT
Larrea nitida is a plant that belongs to the Zygophyllaceae family and is widely used in South America to treat inflammatory diseases, tumors and menstrual pain. However, its pharmacological activity remains unclear. In this study we evaluated the property of selective estrogen receptor modulator (SERM) of Larrea nitida extracts (LNE) as a phytoestrogen that can mimic, modulate or disrupt the actions of endogenous estrogens, depending on the tissue and relative amount of other SERMs. To investigate the property of SERM of LNE, we performed MCF-7 cell proliferation assays, estrogen response element (ERE)-luciferase reporter gene assay, human estrogen receptor (hER) binding assays and in vivo uterotrophic assay. To gain insight into the active principles, we performed a bioassay-guided analysis of LNE employing solvents of various polarities and using classical column chromatography, which yielded 16 fractions (LNs). LNE showed high binding affinities for hERalpha and hERbeta with IC50 values of 1.20x10(-7) g/ml and 1.00x10(-7) g/ml, respectively. LNE induced 17beta-estradiol (E2)-induced MCF-7 cell proliferation, however, it reduced the proliferation in the presence of E2. Furthermore, LNE had an atrophic effect in the uterus of immature rats through reducing the expression level of progesterone receptor (PR) proteins. LN08 and LN10 had more potent affinities for binding on hER alpha and beta than other fractions. Our results indicate that LNE had higher binding affinities for hERbeta than hERalpha, and showed SERM properties in MCF-7 breast cancer cells and the rat uterus. LNE may be useful for the treatment of estrogen-related conditions, such as female cancers and menopause.