TY - JOUR
T1 - Messenger RNA stability of parathyroid hormone-related protein regulated by transforming growth factor-β1
AU - Sellers, R. S.
AU - Capen, C. C.
AU - Rosol, Thomas J.
N1 - Funding Information:
This work was supported by the National Institutes of Health, United States Public Health Service grants CA-77911 (to Thomas J. Rosol) and CA79110-01 (to R.S. Sellers). Sincere thanks go to Shelly Lenz for her contributions to this project, to William Philbrick for his information, advice, and materials, and to Tim Vojt for his graphical expertise.
PY - 2002/2/25
Y1 - 2002/2/25
N2 - Humoral hypercalcemia of malignancy (HHM), a paraneoplastic syndrome associated with epithelial cancers, including squamous cell carcinoma (SCC), is due to expression and secretion of parathyroid hormone-related protein (PTHrP). Transforming growth factor-β1 (TGFβ1), expressed by many tumors, has been demonstrated in vitro to increase the half-life of PTHrP mRNA. In this study, oral squamous carcinoma cells (SCC2/88) had a two-fold increase in PTHrP mRNA stability (from 45 to 90 min) in response to treatment with TGFβ1. In order to examine the mechanism of TGFβ1-mediated PTHrP mRNA stability, a cell-free assay of mRNA degradation was utilized in which the degradation of in vitro-transcribed mRNA incubated with cytoplasmic protein extracts from SCC2/88 treated with vehicle or TGFβ1 was measured. In this assay, full-length PTHrP mRNA was not significantly stabilized in TGFβ1-treated samples when compared to vehicle treated samples. However, there was a striking (>5-fold) increase in PTHrP mRNA half-life in TGFβ1-treated samples when PTHrP mRNA lacked the 3′-untranslated region (3′-UTR). In contrast, the degradation of 3′-UTR-truncated PTHrP mRNA using the cell-free assay was not altered in vehicle-treated samples. UV cross-linking of PTHrP mRNA and cytoplasmic proteins from cells treated with either vehicle or TGFβ1 revealed numerous mRNA-binding proteins. TGFβ1 treatment resulting in decreased binding of 33, 31, 27, 20 and 18 kDa binding proteins to the terminal coding region. These studies revealed that TGFβ1-induced PTHrP mRNA stability might be, in part, the result of cis-acting sequences within the coding region of the PTHrP mRNA.
AB - Humoral hypercalcemia of malignancy (HHM), a paraneoplastic syndrome associated with epithelial cancers, including squamous cell carcinoma (SCC), is due to expression and secretion of parathyroid hormone-related protein (PTHrP). Transforming growth factor-β1 (TGFβ1), expressed by many tumors, has been demonstrated in vitro to increase the half-life of PTHrP mRNA. In this study, oral squamous carcinoma cells (SCC2/88) had a two-fold increase in PTHrP mRNA stability (from 45 to 90 min) in response to treatment with TGFβ1. In order to examine the mechanism of TGFβ1-mediated PTHrP mRNA stability, a cell-free assay of mRNA degradation was utilized in which the degradation of in vitro-transcribed mRNA incubated with cytoplasmic protein extracts from SCC2/88 treated with vehicle or TGFβ1 was measured. In this assay, full-length PTHrP mRNA was not significantly stabilized in TGFβ1-treated samples when compared to vehicle treated samples. However, there was a striking (>5-fold) increase in PTHrP mRNA half-life in TGFβ1-treated samples when PTHrP mRNA lacked the 3′-untranslated region (3′-UTR). In contrast, the degradation of 3′-UTR-truncated PTHrP mRNA using the cell-free assay was not altered in vehicle-treated samples. UV cross-linking of PTHrP mRNA and cytoplasmic proteins from cells treated with either vehicle or TGFβ1 revealed numerous mRNA-binding proteins. TGFβ1 treatment resulting in decreased binding of 33, 31, 27, 20 and 18 kDa binding proteins to the terminal coding region. These studies revealed that TGFβ1-induced PTHrP mRNA stability might be, in part, the result of cis-acting sequences within the coding region of the PTHrP mRNA.
KW - Parathyroid hormone-related protein
KW - Squamous cell carcinoma
KW - Transforming growth factor-β1
KW - mRNA stability
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U2 - 10.1016/S0303-7207(01)00752-3
DO - 10.1016/S0303-7207(01)00752-3
M3 - Article
C2 - 11911944
AN - SCOPUS:0037169831
SN - 0303-7207
VL - 188
SP - 37
EP - 46
JO - Molecular and Cellular Endocrinology
JF - Molecular and Cellular Endocrinology
IS - 1-2
ER -