Growth inhibition of thyroid follicular cell-derived cancers by the opioid growth factor (OGF) - opioid growth factor receptor (OGFr) axis

<p>Abstract</p> <p>Background</p> <p>Carcinoma of the thyroid gland is an uncommon cancer, but the most frequent malignancy of the endocrine system. Most thyroid cancers are derived from the follicular cell. Follicular carcinoma (FTC) is considered more malignant than papillary thyroid carcinoma (PTC), and anaplastic thyroid cancer (ATC) is one of the most lethal human cancers. Opioid Growth Factor (OGF; chemical term - [Met⁵]-enkephalin) and its receptor, OGFr, form an inhibitory axis regulating cell proliferation. Both the peptide and receptor have been detected in a wide variety of cancers, and OGF is currently used clinically as a biotherapy for some non-thyroid neoplasias. This study addressed the question of whether the OGF-OGFr axis is present and functional in human thyroid follicular cell - derived cancer.</p> <p>Methods</p> <p>Utilizing human ATC (KAT-18), PTC (KTC-1), and FTC (WRO 82-1) cell lines, immunohistochemistry was employed to ascertain the presence and location of OGF and OGFr. The growth characteristics in the presence of OGF or the opioid antagonist naltrexone (NTX), and the specificity of opioid peptides for proliferation of ATC, were established in KAT-18 cells. Dependence on peptide and receptor were investigated using neutralization studies with antibodies and siRNA experiments, respectively. The mechanism of peptide action on DNA synthesis and cell survival was ascertained. The ubiquity of the OGF-OGFr axis in thyroid follicular cell-derived cancer was assessed in KTC-1 (PTC) and WRO 82-1 (FTC) tumor cells.</p> <p>Results</p> <p>OGF and OGFr were present in KAT-18 cells. Concentrations of 10^-6M OGF inhibited cell replication up to 30%, whereas NTX increased cell growth up to 35% relative to cultures treated with sterile water. OGF treatment reduced cell number by as much as 38% in KAT-18 ATC in a dose-dependent and receptor-mediated manner. OGF antibodies neutralized the inhibitory effects of OGF, and siRNA knockdown of OGFr negated growth inhibition by OGF. Cell survival was not altered by OGF, but DNA synthesis as recorded by BrdU incorporation was depressed by 28% in OGF-treated cultures compared to those exposed to sterile water. The OGF-OGFr axis was detected and functional in PTC (KTC-1) and FTC (WRO 82-1) cell lines.</p> <p>Conclusion</p> <p>These data suggest that OGF and OGFr are present in follicular-derived thyroid cancers, and that OGF serves in a tonically active inhibitory manner to maintain homeostasis of cell proliferation. These results may provide a biotherapeutic strategy in the treatment of these cancers.</p

The OGF-OGFr axis utilizes the p21 pathway to restrict progression of human pancreatic cancer

<p>Abstract</p> <p>Background</p> <p>Pancreatic cancer is the 4th leading cause of death from cancer in the U.S. The opioid growth factor (OGF; [Met⁵]-enkephalin) and the OGF receptor form an inhibitory growth regulatory system involved in the pathogenesis and treatment of pancreatic cancer. The OGF-OGFr axis influences the G₀/G₁phase of the cell cycle. In this investigation, we elucidate the pathway of OGF in the cell cycle.</p> <p>Results</p> <p>Using BxPC-3 cells, OGF decreased phosphorylation of retinoblastoma (Rb) protein without changing total Rb. This change was correlated with reduced cyclin-dependent kinase protein (Cdk) 2 kinase activity, but not total Cdk2. OGF treatment increased cyclin-dependent kinase inhibitor (CKI) p21 protein expression in comparison to controls, as well levels of p21 complexed with Cdk2. Naloxone abolished the increased expression of p21 protein by OGF, suggesting a receptor-mediated activity. p21 specific siRNAs blocked OGF's repressive action on proliferation in BxPC-3, PANC-1, and Capan-2 cells; cells transfected with negative control siRNA had no alteration in p21 expression, and therefore were inhibited by OGF.</p> <p>Conclusion</p> <p>These data are the first to reveal that the target of cell proliferative inhibitory action of OGF in human pancreatic cancer is a p21 CKI pathway, expanding strategies for diagnosis and treatment of these neoplasias.</p

Enkephalin Therapy Improves Relapsing-Remitting Multiple Sclerosis

Multiple sclerosis (MS) is accompanied by decreases in serum endogenous enkephalin/endorphins and alterations in inflammatory cytokines. This retrospective analysis of serum levels was conducted in 53 patients with established relapsing-remitting MS treated with the disease-modifying therapies (DMT) glatiramer acetate, dimethyl fumarate or with the biotherapeutic low dose naltrexone (LDN) to elevate enkephalins, an off-label alternative. Opioid growth factor (OGF), an inhibitory endogenous opioid involved in modulating cellular replication, was measured and correlated to serum β-endorphin, IL-17A and TNFα. Results revealed that MS leads to a significant reduction in OGF levels in subjects on DMTs, but patients on LDN had OGF levels comparable to non-MS controls. Individuals on DMTs had significantly elevated TNFα levels, while IL-17A levels were significantly elevated only in patients taking dimethyl fumarate. A direct correlation was established between OGF and IL17A indicating a potential interaction between the OGF-OGFr axis and pro-inflammatory T-helper cells providing insight into the disease etiology

Opioid growth factor receptor (OGFR) expression is downregulated with progression of triple negative breast cancer

Purpose: Triple negative breast cancer (TNBC) is an aggressive form of breast cancer that accounts for approximately 15% of the newly diagnosed cancers worldwide, and disproportionately affects younger women and women of color. Although many forms of breast cancer are successfully treated, new therapies are needed for TNBC. A novel regulatory system, the opioid growth factor (OGF) – opioid growth factor receptor (OGFr) axis, plays a determining role in neoplasia. OGF is an endogenous peptide that binds specifically to OGFr to inhibit cell replication. As some human cancers grow, OGFr expression is diminished, thus limiting the therapeutic efficacy of OGF. The OGF-OGFr axis is present in human TNBC cell line MDA-MB-231 and OGF  inhibits cell replication in a dosage-related, receptor-mediated manner. Methods: The present study investigated whether OGFr protein expression in human breast cancer cell lines grown in vitro or transplanted into nude mice, changed with the stage of proliferation or size of tumor using western blotting, semi-quantitative immunohistochemistry, and DNA synthesis techniques. Results: Comparison of log and confluent TNBC cultures revealed that OGF expression was significantly decreased in confluent cultures relative to levels in log-phase cells. Western blot analyses confirmed that OGFr was reduced in confluent TNBC and MCF-7 breast cancer cells in comparison to corresponding log-phase cells. Moreover, BrdU labeling was reduced in confluent cells. Small (&lt;500 mm3) and large (&gt;1000 mm3) TNBC tumors grown in nude mice were processed for semiquantitative   measurement of OGF and OGFr. The expression of both peptide and receptor in large tumors was downregulated relative to small tumors. Conclusion: The reduced expression of the inhibitory peptide and receptor diminishes the efficacy of the OGF-OGFr axis as a biotherapy. These data suggest that the OGF-OGFr pathway is altered with cancer progression and one or more elements of this regulatory pathway may serve as biomarkers for TNBC growth

Opioid growth factor receptor (OGFR) expression is downregulated with progression of triple negative breast cancer

Purpose: Triple negative breast cancer (TNBC) is an aggressive form of breast cancer that accounts for approximately 15% of the newly diagnosed cancers worldwide, and disproportionately affects younger women and women of color. Although many forms of breast cancer are successfully treated, new therapies are needed for TNBC. A novel regulatory system, the opioid growth factor (OGF) – opioid growth factor receptor (OGFr) axis, plays a determining role in neoplasia. OGF is an endogenous peptide that binds specifically to OGFr to inhibit cell replication. As some human cancers grow, OGFr expression is diminished, thus limiting the therapeutic efficacy of OGF. The OGF-OGFr axis is present in human TNBC cell line MDA-MB-231 and OGF  inhibits cell replication in a dosage-related, receptor-mediated manner. Methods: The present study investigated whether OGFr protein expression in human breast cancer cell lines grown in vitro or transplanted into nude mice, changed with the stage of proliferation or size of tumor using western blotting, semi-quantitative immunohistochemistry, and DNA synthesis techniques. Results: Comparison of log and confluent TNBC cultures revealed that OGF expression was significantly decreased in confluent cultures relative to levels in log-phase cells. Western blot analyses confirmed that OGFr was reduced in confluent TNBC and MCF-7 breast cancer cells in comparison to corresponding log-phase cells. Moreover, BrdU labeling was reduced in confluent cells. Small (&lt;500 mm3) and large (&gt;1000 mm3) TNBC tumors grown in nude mice were processed for semiquantitative   measurement of OGF and OGFr. The expression of both peptide and receptor in large tumors was downregulated relative to small tumors. Conclusion: The reduced expression of the inhibitory peptide and receptor diminishes the efficacy of the OGF-OGFr axis as a biotherapy. These data suggest that the OGF-OGFr pathway is altered with cancer progression and one or more elements of this regulatory pathway may serve as biomarkers for TNBC growth.</p

reBody Weight Evolution of Tsurcana Pure Breed Lambs and Tsurcana Crossed with Blanc Du Massif Central Lambs (F1)

The Blanc du Massif Central breed is a rustically French meat breed of sheep that was used in crossing with Tsurcana breed in order to improve the quality of local lambs for the European market. After crossing, the resulting lambs were compared with purebred Tsurcana lambs to evaluate daily weight gain from birth to 3 months. The daily weight gain was superior in the crossed lambs compared with purebred lambs

Opioid growth factor modulates angiogenesis

AbstractObjective: Induced angiogenesis has recently been attempted as a therapeutic modality in patients with occlusive arterial atherosclerotic disease. We investigated the possible role of endogenous opioids in the modulation of angiogenesis. Methods: Chick chorioallantoic membrane was used as an in vivo model to study angiogenesis. Fertilized chick eggs were incubated for 3 days, explanted, and incubated for an additional 2 days. Three-millimeter methylcellulose disks were placed on the surface of the chorioallantoic membrane; each disk contained opioid growth factor ([Met5]-enkephalin; 5 μg), the short-acting opioid receptor antagonist naloxone (5 μg), opioid growth factor and naloxone together (5 μg of each), the long-acting opioid antagonist naltrexone (5 μg), or distilled water (control). A second series of experiments was performed with distilled water, the angiogenic inhibitor retinoic acid (1 μg), and vascular endothelial growth factor (1 μg) to further evaluate our model. The developing vasculature was imaged 2 days later with a digital camera and exported to a computer for image analysis. Total number of blood vessels, total vessel length, and mean vessel length were measured within a 100-mm2 region surrounding each applied disk. Immunocytochemical analysis was performed with antibodies directed against opioid growth factor and its receptor (OGFr). Results: Opioid growth factor had a significant inhibitory effect on angiogenesis, both the number of blood vessels and the total vessel length being decreased (by 35% and 20%, respectively) in comparison with control levels (P <.005). The simultaneous addition of naloxone and opioid growth factor had no effect on blood vessel growth, nor did naloxone alone. Chorioallantoic membranes exposed to naltrexone displayed increases of 51% and 24% in blood vessel number and length, respectively, in comparison with control specimens (P <.005). These results indicate that the opioid growth factor effects are receptor mediated and tonically active. Immunocytochemistry demonstrated the presence of both opioid growth factor and OGFr within the endothelial cells and mesenchymal cells of the developing chorioallantoic membrane vessel wall. Retinoic acid significantly reduced the number and the total length of blood vessels, whereas vascular endothelial growth factor increased both the number and the length of blood vessels in comparison with the controls (P <.0001). The magnitude of opioid growth factor's effects were comparable to those seen with retinoic acid, whereas inhibition of opioid growth factor with naltrexone induced an increase in total vessel length comparable to that for vascular endothelial growth factor. Conclusions: These results demonstrate for the first time that endogenous opioids modulate in vivo angiogenesis. Opioid growth factor is a tonically active peptide that has a receptor-mediated action in regulating angiogenesis in developing endothelial and mesenchymal vascular cells. (J Vasc Surg 2000;32:364-73.