Oestradiol enhances plasma growth hormone and insulin-like growth factor-I concentrations and increased the expression of their receptors mRNAs in the liver of ovariectomized cows

Many metabolic hormones, growth hormone (GH), insulin-like growth factor-I (IGF-I) and insulin affect ovarian functions. However, whether ovarian steroid hormones affect metabolic hormones in cattle remains unknown. This study aimed to determine the effect of sex steroids on the plasma profiles of GH, IGF-I and insulin and their receptors in the liver and adipose tissues of dairy cows. Ovariectomized cows (n = 14) were randomly divided into four groups: control group (n = 3) was treated with saline on Day 0; oestradiol (E2) group (n = 3), with saline and 1 mg oestradiol benzoate (EB) on Day 0 and 5, respectively; progesterone (P4) group (n = 4) with two CIDRs (Pfizer Inc., Tokyo, Japan) from Day 0; and E2 + P4 group (n = 4) with two CIDRs on Day 0 that were removed on Day 6 and were immediately injected with 1 mg EB. The animals were euthanized after the experiment, and liver and adipose tissues samples were quantitatively analysed using real-time PCR for the expression of mRNA for the GH (GHR), IGF-I (IGFR-I) and insulin (IR) receptor mRNAs. Oestradiol benzoate significantly increased the number of peaks (p < 0.05), pulse amplitude (p < 0.05) and area under the curve (AUC; p < 0.01) for plasma GH; moreover, it increased plasma IGF-I concentration (p < 0.05), but it had no effect on the plasma insulin profile. P4 significantly decreased the AUC (p < 0.01), compared with the control group, whereas it did not affect the number of peaks and the amplitude of GH pulses. P4 + E2 did not affect the GH pulse profile. E2 increased the mRNA expression of GHR, IGFR-I and IR in the liver (p < 0.05), whereas both P4 and E2 + P4 did not change their expressions. Our results provide evidence that the metabolic and reproductive endocrine axes may regulate each other to ensure optimal reproductive and metabolic function.

Human epidermal growth factor receptor-2 gene amplification in gastric cancer using tissue microarray technology

To assess human epidermal growth factor receptor-2 (HER2)-status in gastric cancer and matched lymph node metastases by immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH).

RNA interference screening identifies a novel role for autocrine fibroblast growth factor signaling in neuroblastoma chemoresistance

Chemotherapeutic drug resistance is one of the major causes for treatment failure in high-risk neuroblastoma (NB), the most common extra cranial solid tumor in children. Poor prognosis is typically associated with MYCN amplification. Here, we utilized a loss-of-function kinome-wide RNA interference screen to identify genes that cause cisplatin sensitization. We identified fibroblast growth factor receptor 2 (FGFR2) as an important determinant of cisplatin resistance. Pharmacological inhibition of FGFR2 confirmed the importance of this kinase in NB chemoresistance. Silencing of FGFR2 sensitized NB cells to cisplatin-induced apoptosis, which was regulated by the downregulation of the anti-apoptotic proteins BCL2 and BCLX(L). Mechanistically, FGFR2 was shown to activate protein kinase C-δ to induce BCL2 expression. FGFR2, as well as the ligand fibroblast growth factor-2, were consistently expressed in primary NB and NB cell lines, indicating the presence of an autocrine loop. Expression analysis revealed that FGFR2 correlates with MYCN amplification and with advanced stage disease, demonstrating the clinical relevance of FGFR2 in NB. These findings suggest a novel role for FGFR2 in chemoresistance and provide a rational to combine pharmacological inhibitors against FGFR2 with chemotherapeutic agents for the treatment of NB.Oncogene advance online publication, 1 October 2012; doi:10.1038/onc.2012.416.

Epidermal growth factor receptor, phosphatidylinositol-3-kinase catalytic subunit/PTEN, and KRAS/NRAS/BRAF in primary resected esophageal adenocarcinomas: loss of PTEN is associated with worse clinical outcome

Alterations of the epidermal growth factor receptor (EGFR) can be observed in a significant subset of esophageal adenocarcinomas (EACs), and targeted therapy against EGFR may become an interesting approach for the treatment of these tumors. Mutations of KRAS, NRAS, BRAF, and phosphatidylinositol-3-kinase catalytic subunit (PIK3CA) and deregulation of PTEN expression influence the responsiveness against anti-EGFR therapy in colorectal carcinomas. We investigated the prevalence of these events in a collection of 117 primary resected EACs, correlated the findings with EGFR expression and amplification, and determined their clinicopathologic impact. KRAS mutations were detected in 4 (3%) of 117 tumors (3× G12D and 1 G12V mutation). One tumor had a PIK3CA E545K mutation. Neither NRAS nor BRAF mutations were detected. Sixteen (14%) of 117 cases were negative for PTEN expression, determined by immunohistochemistry. Loss of PTEN was observed predominantly in advanced tumor stages (P = .004). There was no association between PTEN and EGFR status. Loss of PTEN was associated with shorter overall and disease-free survival (P < .001 each) and also an independent prognostic factor in multivariate analysis (P = .015). EGFR status had no prognostic impact in this case collection. In summary, loss of PTEN can be detected in a significant subset of EAC and is associated with an aggressive phenotype. Therefore, PTEN may be useful as a prognostic biomarker. In contrast, mutations of RAS/RAF/PIK3CA appear only very rarely, if at all, in EAC. A possible predictive role of PTEN in anti-EGFR treatment warrants further investigations, whereas determination of RAS/RAF/PIK3CA mutations may only have a minor impact in this context.

Prolyl hydroxylase inhibitors increase the production of vascular endothelial growth factor in dental pulp-derived cells

Introduction: Prolyl hydroxylase (PHD) inhibitors can induce a proangiogenic response that stimulates regeneration in soft and hard tissues. However, the effect of PHD inhibitors on the dental pulp is unclear. The purpose of this study was to evaluate the effects of PHD inhibitors on the proangiogenic capacity of human dental pulp–derived cells. Methods: To test the response of dental pulp–derived cells to PHD inhibitors, the cells were exposed to dimethyloxalylglycine, desferrioxamine, L-mimosine, and cobalt chloride. To assess the response of dental pulp cells to a capping material supplemented with PHD inhibitors, the cells were treated with supernatants from calcium hydroxide. Viability, proliferation, and protein synthesis were assessed by formazan formation, 3[H]thymidine, and 3[H]leucine incorporation assays. The effect on the proangiogenic capacity was measured by immunoassays for vascular endothelial growth factor (VEGF). Results: We found that all 4 PHD inhibitors can reduce viability, proliferation, and protein synthesis at high concentrations. At nontoxic concentrations and in the presence of supernatants from calcium hydroxide, PHD inhibitors stimulated the production of VEGF in dental pulp–derived cells. When calcium hydroxide was supplemented with the PHD inhibitors, the supernatants from these preparations did not significantly elevate VEGF levels. Conclusions: These results show that PHD inhibitors can stimulate VEGF production of dental pulp–derived cells, suggesting a corresponding increase in their proangiogenic capacity. Further studies will be required to understand the impact that this might have on pulp regeneration.

Angiotensin Ii As A General Growth Factor

Angiotensin II (Ang II), a key protein in the renin-angiotensin system, can induce cardiac hypertrophy through an intracrine system as well as affect gene transcription. The receptor to Ang II responsible for this effect, AT1, has been localized to the nucleus of cell types in addition to cardiomyocytes. In this study, we induced expression of Ang II in MC3T3 osteoblasts and K7M2 osteosarcomas and measured changes in protein expression of Annexin V and matrix metalloproteinase 2 (MMP2), proteins identified previously through mass spectrometry analysis as being regulated by Ang II. Annexin V is downregulated in both immortalized murine bone (MC3T3) cells and in cancerous immortalized murine (K7M2) cells induced to express Ang II. MC3T3 cells which express Ang II show a downregulation of MMP2 expression, but Ang II-expressing K7M2 cells show an upregulation of MMP2. The differential regulation of MMP2 between the cancerous cells and noncancerous cells implicates a role for Ang in in tumor metastasis, as MMP2 is a metastatic protein. Annexin V is used as a marker for apoptosis, but nothing is known of the function of the endogenous protein. That Annexin V is potentially regulated by Ang II provides more information with which to characterize the protein and could suggest a function for Annexin V as part of a signal transduction pathway inside of the cell.

Vascular endothelial growth factor induces contralesional corticobulbar plasticity and functional neurological recovery in the ischemic brain

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor, which also has neuroprotective activity. In view of these dual actions on vessels and neurons, we were interested whether VEGF promotes long distance axonal plasticity in the ischemic brain. Herein, we show that VEGF promotes neurological stroke recovery in mice when delivered in a delayed way starting 3 days after middle cerebral artery occlusion. Using anterograde tract-tracing experiments that we combined with histochemical and molecular biological studies, we demonstrate that although VEGF promoted angiogenesis predominantly in the ischemic hemisphere, pronounced axonal sprouting was induced by VEGF in the contralesional, but not the ipsilesional corticobulbar system. Corticobulbar plasticity was accompanied by the deactivation of the matrix metalloproteinase MMP9 in the lesioned hemisphere and the transient downregulation of the axonal growth inhibitors NG2 proteoglycan and brevican and the guidance molecules ephrin B1/2 in the contralesional hemisphere. The regulation of matrix proteinases, growth inhibitors, and guidance molecules offers insights how brain plasticity is controlled in the ischemic brain.

Targeting the insulin-like growth factor-1 receptor in human cancer

The insulin-like growth factor (IGF) signaling system plays a crucial role in human cancer and the IGF-1 receptor (IGF-1R) is an attractive drug target against which a variety of novel anti-tumor agents are being developed. Deregulation of the IGF signaling pathway frequently occurs in human cancer and involves the establishment of autocrine loops comprising IGF-1 or IGF-2 and/or IGF-1R over-expression. Epidemiologic studies have documented a link between elevated IGF levels and the development of solid tumors, such as breast, colon, and prostate cancer. Anti-cancer strategies targeting the IGF signaling system involve two main approaches, namely neutralizing antibodies and small molecule inhibitors of the IGF-1R kinase activity. There are numerous reports describing anti-tumor activity of these agents in pre-clinical models of major human cancers. In addition, multiple clinical trials have started to evaluate the safety and efficacy of selected IGF-1R inhibitors, in combination with standard chemotherapeutic regimens or other targeted agents in cancer patients. In this mini review, I will discuss the role of the IGF signaling system in human cancer and the main strategies which have been so far evaluated to target the IGF-1R.

Vascular endothelial growth factor-A and aldosterone: relevance to normal pregnancy and preeclampsia

Aldosterone levels are markedly elevated during normal pregnancy but fall even though volume contracts when preeclampsia occurs. The level of aldosterone in either condition cannot be explained solely by the activity of the renin-angiotensin II system. In normal gestation, vascular endothelial growth factor (VEGF) is thought to maintain vascular health, but its role in adrenal hormone production is unknown. We hypothesized that the role of VEGF in the adrenal gland is to maintain vascular health and regulate aldosterone production. Here, we demonstrate that supernatant of endothelial cells grown in the presence of VEGF enhanced aldosterone synthase activity in human adrenocortical cells. VEGF either alone or combined with angiotensin II increased aldosterone production in adrenal cells. These data suggest that endothelial cell-dependent and independent activation of aldosterone is regulated by VEGF. In contrast to angiotensin II, VEGF did not upregulate the steroidogenic acute regulatory protein. Consistent with this observation, angiotensin II stimulated both aldosterone and cortisol synthesis from progesterone, whereas VEGF stimulated selectively aldosterone production. In rats, overexpression of soluble fms-like tyrosine kinase-1, an endogenous VEGF inhibitor, led to adrenocortical capillary rarefaction and fall in aldosterone concentrations that correlated inversely with soluble fms-like tyrosine kinase-1 levels. These findings may explain why aldosterone increases so markedly during normal gestation and why preeclampsia, a condition characterized by high soluble fms-like tyrosine kinase-1, is associated with inappropriately low aldosterone levels in spite of relatively lower plasma volumes.

Reduced nuclear translocation of nuclear factor (NF)-kappaB p65 in the footpad epidermis of dogs infected with distemper virus

Infection of canine footpads with the canine distemper virus (CDV) can cause massive epidermal thickening (hard pad disease), as a consequence of increased proliferation of keratinocytes and hyperkeratosis. Keratinocytes of canine footpad epidermis containing detectable CDV nucleoprotein antigen and CDV mRNA were shown previously to have increased proliferation indices. Because various proteins that play a role in the proliferation of epidermal cells are viral targets, the potential participation of such proteins in CDV-associated keratinocyte proliferation was investigated. Transforming growth factor-alpha (TGF-alpha), cell cycle regulatory proteins p21, p27 and p53, and nuclear factor (NF)-kappaB transcription factor components p50 and p65 were studied in the footpad epidermis from the following groups of dogs inoculated with CDV: group 1, consisting of seven dogs with clinical distemper and CDV in the footpad epidermis; group 2, consisting of four dogs with clinical distemper but no CDV in the footpad epidermis; group 3, consisting of eight dogs with neither clinical distemper nor CDV in the footpad epithelium. Group 4 consisted of two uninoculated control dogs. The expression of TGF-alpha, p21, p27 and p53, and p50 in the basal layer, lower and upper spinous layers, and in the granular layer did not differ statistically between CDV-positive (group 1) and CDV-negative (groups 2-4) footpad epidermis. However, there were differences in the levels of nuclear and cytoplasmic p65 expression between group 1 dogs and the other three groups. Thus, footpads from group 1 dogs had more keratinocytes containing p65 in the cytoplasm and, conversely, fewer nuclei that were positive for p65. These findings indicate that p65 translocation into the nucleus is reduced in CDV-infected footpad epidermis. Such decreased translocation of p65 may help to explain increased keratinocyte proliferation in hard pad disease and suggests interference of CDV with the NF-kappaB pathway.