Effect of an oral astaxanthin prodrug (CDX-085) on lipoprotein levels and progression of atherosclerosis in LDLR(-/-) and ApoE(-/-) mice.

Unlabelled: Oxidative stress and inflammation are key promoters of atherosclerosis and myocardial damage. When orally administered, the novel astaxanthin prodrug CDX-085 delivers high levels of the xanthophyll antioxidant astaxanthin that protects LDL from oxidation and reduces primary thrombosis. In this study, we analyzed whether delivery of astaxanthin from administration of the CDX-085 prodrug reduces plasma lipoprotein levels and the progression of atherosclerosis in low-density lipoprotein receptor negative (LDLR(-/-)) and apolipoprotein E deficient (ApoE(-/-)) mice.

Novel astaxanthin prodrug (CDX-085) attenuates thrombosis in a mouse model.

Background: Cardiovascular disease remains the leading cause of morbidity and premature mortality in most industrialized countries as well as in developing nations. A pro-oxidative state appears to promote and/or exacerbate vascular disease complications. Furthermore, a state of low-grade chronic inflammation can promote increased oxidative stress and lead to endothelial cell and platelet dysfunction ultimately contributing to thrombogenesis.

Analysis of Connexin43 phosphorylated at S325, S328 and S330 in normoxic and ischemic heart.

The functional consequences of Connexin43 (Cx43) phosphorylation remain largely unexplored. Using an antibody that specifically recognizes Cx43 phosphorylated at serine residues 325, 328 and/or 330 (pS325/328/330-Cx43), we show that labeling of this form of Cx43 as well as of total Cx43 is restricted to the intercalated disk region of normal ventricular tissue. In ischemic heart, significant relocalization of total Cx43 to the lateral edges of myocytes was evident; however pS325/328/330-Cx43 remained predominately at the intercalated disk.

Selectivity of connexin 43 channels is regulated through protein kinase C-dependent phosphorylation.

Coordinated contractile activation of the heart and resistance to ischemic injury depend, in part, on the intercellular communication mediated by Cx43-composed gap junctions. The function of these junctions is regulated at multiple levels (assembly to degradation) through phosphorylation at specific sites in the carboxyl terminus (CT) of the Cx43 protein. We show here that the selective permeability of Cx43 junctions is regulated through protein kinase C (PKC)-dependent phosphorylation at serine 368 (S368).

Altered tumor biology and tumorigenesis in irradiated and chemical carcinogen-treated single and combined connexin32/p27Kip1-deficient mice.

Connexin32 knockout mice (Cx32-KO) exhibit increased chemical and radiation-induced liver and lung tumorigenesis. This increased tumor incidence is associated with altered tumor biology including enhanced tumor progression and an increased percent of MAPK-active tumors. Likewise, mice lacking the tumor suppressor/cell cycle regulator p27Kip1 exhibit increased tumorigenesis in a variety of tissues following chemical and radiation induction.

Connexins as targets for cancer chemoprevention and chemotherapy.

Cells within a tissue continuously interact to coordinate normal tissue functions and maintain homeostasis. Gap junctional communication (GJC), mediated by the connexin protein family, allows this type of intercellular crosstalk resulting in synchronized and cooperative tissue behavior such as cardiac contraction. In cancer, loss of these types of cell:cell interactions has been shown to facilitate tumorigenesis and enable the autonomous cell behavior associated with transformed cells.

Temporal regulation of connexin phosphorylation in embryonic and adult tissues.

Gap junctions, composed of proteins from the connexin family, allow for intercellular communication between cells in tissues and are important in development, tissue/cellular homeostasis, and carcinogenesis. Genome databases indicate that there are at least 20 connexins in the mouse and human. Connexin phosphorylation has been implicated in connexin assembly into gap junctions, gap junction turnover, and cell signaling events that occur in response to tumor promoters and oncogenes.

Deficiency in the gap junction protein connexin32 alters p27Kip1 tumor suppression and MAPK activation in a tissue-specific manner.

Connexin32 knockout mice (Cx32-KO) exhibit increased chemical- and radiation-induced liver and lung tumor formation with many lung tumors demonstrating decreased levels of the tumor suppressor p27KIP1. To determine if p27 deficiency alters Cx32-influenced tumorigenesis, we have generated a Cx32/p27 double-deficient mouse strain (DKO) and show here that exposure of these mice to X-ray radiation resulted in an increase or decrease in tumorigenesis depending on the tissue. Several tissues were highly sensitive to loss of p27 tumor suppressor function (intestine, adrenal, pituitary) resulting in an increased overall tumor burden in DKO mice compared to both wild-type (P<0.

The gap junction protein connexin32 is a mouse lung tumor suppressor.

Although loss of connexin expression and/or gap junction intercellular communication correlates with decreased growth control and increased neoplastic potential, there is limited evidence directly linking gap junction intercellular communication function with tumor suppression in situ. Here, we show for the first time that a gap junction protein, connexin32 (Cx32), acts as a lung tumor suppressor in a mouse model. Cx32-deficient nontumorous lung tissue exhibited an increased proliferative index (P < 0.

Mice deficient for the gap junction protein Connexin32 exhibit increased radiation-induced tumorigenesis associated with elevated mitogen-activated protein kinase (p44/Erk1, p42/Erk2) activation.

Loss of connexin expression/gap junction intercellular communication (GJIC) has been correlated with decreased growth control and increased tumorigenesis. Studies utilizing Connexin32 (Cx32)-deficient knockout mice have demonstrated that loss of Cx32 increases susceptibility to chemically induced liver tumorigenesis. Here, in addition to dramatically increased liver tumorigenesis, we show that tumor induction utilizing X-ray radiation resulted in a statistically significant increase in overall tumor burden in Cx32-deficient mice compared with wild-type mice due to tumorigenesis in several other tissues (lung, adrenal, lymph and small intestine) even when excluding prevalent liver tumors.

Inducible expression of the gap junction protein connexin43 decreases the neoplastic potential of HT-1080 human fibrosarcoma cells in vitro and in vivo.

Numerous studies have demonstrated a correlation between dysregulation/loss of connexin expression or gap junction intercellular communication (GJIC) function and decreased growth control both in human tumors and tumor cell lines. Likewise, restoration of constitutive connexin expression/function is correlated with increased growth control/decreased tumorigenicity. Here, we show for the first time that inducible restoration of connexin43 (Cx43) expression and GJIC function in a human tumor line of mesenchymal origin (HT-1080, fibrosarcoma) resulted in a lowered neoplastic potential.

Somatic cell nuclear transfer in the pig: control of pronuclear formation and integration with improved methods for activation and maintenance of pregnancy.

To clone a pig from somatic cells, we first validated an electrical activation method for use on ovulated oocytes. We then evaluated delayed versus simultaneous activation (DA vs. SA) strategies, the use of 2 nuclear donor cells, and the use of cytoskeletal inhibitors during nuclear transfer.