CCN5 Expression, Localization, and Function in Smooth Muscle Cells.
Abstract: CCN5, a
member of the CCN family of growth factors, inhibits the proliferation and migration of
smooth muscle cells in cell culture and animal models. Expressed in both embryonic and
adult tissues, CCN5 exhibits a matricellular localization pattern characteristic of
secreted proteins that are closely associated with the cell surface. In addition to this
observed expression pattern, ... read moreimmunohistochemical evidence suggests the presence of
nuclear CCN5 in some cells. In chapter two of this thesis I show that CCN5 is a nuclear
protein through immunohistochemistry, confocal imaging, and cell fractionation. Using
site directed mutagenesis we confirm that the identified putative nuclear localization
signal in the VWC domain of rat CCN5 is not necessary for nuclear localization. The
third chapter of this thesis explores the effect of CCN5 on cell cycle proteins in
myometrial smooth muscle cells (SMC). Preliminary microarray data suggests that CCN5
increases p27 and p21 mRNA and decreases cyclin D1 mRNA expression in vascular SMC.
Forced expression of CCN5 in vascular SMC released from growth arrest delays cyclin D1
protein expression. In contrast to these observations made in vascular SMC, I found that
CCN5 had no effect on cyclin D1, p21, or p27 in myometrial SMC suggesting that CCN5
expression may affect proliferation of vascular and myometrial SMC by different
mechanisms. Observations from both cell culture and clinical studies suggest that the
selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene and the
progesterone antagonist mifepristone may be effective therapeutics for uterine
leiomyoma. Chapter 4 of this thesis evaluates the anti-proliferative effects of
tamoxifen, raloxifene, and mifepristone on two patient samples of human uterine
myometrial and leiomyoma SMC. Although raloxifene and tamoxifen had no affect on uterine
SMC proliferation, mifepristone inhibited proliferation of leiomyoma SMC from one
patient sample. Overall the results presented in this thesis provide new insights into
the localization, expression, and function of CCN5 in vascular and myometrial
Thesis (Ph.D.)--Tufts University, 2011.
Submitted to the Dept. of Pharmacology & Experimental Therapeutics.
Advisors: John Castellot Jr., and Theoharis Theoharides.
Committee: Margery Beinfeld, Laura Liscum, and Patricia D'Amore.
Keyword: Pharmacology.read less