title: Parathyroid hormone-related protein overexpression protects goat mammary gland epithelial cells from calcium-sensing receptor activation-induced apoptosis.
abstract: Normal mammary gland epithelial cells and breast cancer cells express the calcium-sensing receptor (CaSR), which is the master regulator of systemic calcium metabolism. During lactation, activation of the CaSR in mammary epithelial cells downregulates parathyroid hormone-related protein (PTHrP) levels in milk and in the circulation, and increases calcium transport into milk. However, very little information is available on the role of CaSR in goat mammary gland epithelial cells (GMECs) apoptosis. In this investigation, the full-length cDNA of CaSR from Xinong Saanen dairy goats was cloned, which contains an open-reading frame of 3,258 bp encoding 1,085 amino acids with a predicted molecular weight of 121.0 kDa and an isoelectric point of 5.65. The amino acid sequence is highly homologous with sheep, and the goat CaSR gene is mapped to chromosome 1. Quantitative real-time PCR suggested that CaSR was predominantly expressed in the heart, kidney and mammary gland. Then, we found the stimulation of CaSR with its activator gadolinium chloride (GdCl3) contributed to increase CaSR mRNA levels in GMECs and simultaneously promoted cell apoptosis, and these effects were abrogated partially by NPS2390 which is an inhibitor of CaSR. We also demonstrated that Ca(2+) increased CaSR mRNA levels and induced GMECs apoptosis and restrained cell proliferation. In contrast, PTHrP overexpression protected GMECs from calcium-induced apoptosis, and promoted cell proliferation. In conclusion, these results suggest that PTHrP overexpression protects GMECs from CaSR activation-induced apoptosis.
authors.affiliation: Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Yongsen
authors.initials: Y
authors.lastname: Sun
authors.forename: Huiling
authors.initials: H
authors.lastname: Zheng
authors.forename: Lihui
authors.initials: L
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Yu
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Yao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D049109:Cell Proliferation / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006041:Goats / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000166:cytology*; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D044162:Parathyroid Hormone-Related Protein / Q000378:metabolism*; D010802:Phylogeny; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D044169:Receptors, Calcium-Sensing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D044162:Parathyroid Hormone-Related Protein; D012333:RNA, Messenger; D044169:Receptors, Calcium-Sensing; D005682:Gadolinium; C038958:gadolinium chloride