Regulation Of Normal Growth Research Articles

Poplar MYB transcription factor PtrMYB012 and its Arabidopsis AtGAMYB orthologs are differentially repressed by the Arabidopsis miR159 family.

A phenotype-based screening of the T1 transgenic Arabidopsis population transformed by overexpression constructs of the entire poplar MYB transcription factor family found that overexpression of a poplar MYB transcription factor, PtrMYB012, in Arabidopsis resulted in upwardly curled rosette leaves, dwarfism and male sterility. Sequence analysis identified that PtrMYB012 is homologous to the Arabidopsis GAMYB genes (e.g., AtMYB65 and AtMYB33). Gene expression analysis revealed that PtrMYB012 is specifically expressed in floral tissues, especially in male catkins, similar to AtMYB65. It was well known that Arabidopsis GAMYBs are negatively regulated by microRNA159 (miR159) during vegetative growth; thus, the typical phenotypes of upwardly curled leaves, dwarfism and male sterility were only shown in overexpression of GAMYBs with mutations in the miR159 target sequence. To confirm our phenotypic consequences, we independently re-produced transgenic Arabidopsis plants overexpressing PtrMYB012 without mutations in the miR159 target sequence. The resulting 35 S::PtrMYB012 Arabidopsis plants phenocopied the previous transgenic Arabidopsis plants, suggesting that PtrMYB012 is probably not a target of Arabidopsis miR159 despite containing the conserved miR159 target sequence. To gain further insight, we produced transgenic poplars overexpressing the intact PtrMYB012. As a result, no conspicuous phenotype was found in 35 S::PtrMYB012 poplar plants. These results suggest that PtrMYB012 transcripts are down-regulated by miR159 in poplar but not in Arabidopsis. Indeed, subsequent 5'-RACE analysis confirmed that PtrMYB012 transcripts are completely degraded in poplar, probably by miR159, but not in Arabidopsis. These results suggest that species-specific family members of miR159 are important for the regulation of normal growth and development in plants.

Analysing plausible futures from past patterns of land change in West Burkina Faso

In a context of fast land changes due to human activity, the old “Malthus vs. Boserup” debate about human pressure on natural resources is more than ever a prevalent subject. We illustrate this debate with an example based on the Tuy Province in West Burkina Faso, which has known an important development these last fifteen years, as mainly observable in the major regression of its natural vegetation.The objective of this article is to question the possible future scenarios of this region, by using a spatial model to understand past land change mechanisms and prospect plausible future ways of development. In particular, the spatial model describes the vegetation clearance processes identified during field campaigns, which we used to draw prospective scenarios and assess their possible effect on natural vegetation evolution.The processing of remote sensing images helped us reveal that one quarter of the total study area was cleared during the last fourteen years. Surveys carried out in the field enabled the identification of the three main processes responsible for these changes: farm size expansion, creation of new farms due to family nuclearization and migrant settlement. The model was then built to reproduce these three processes, and was validated by comparison with the land use classification of remote sensing images. Our model was also used to explore past clearance mechanisms: we found that 90% of the clearance was shared equally between farm size expansion and nuclearization processes, the settlement of migrants being responsible for less than 10% of the clearance. Model outputs also showed a shift in the clearance schemes compared to ancient practices: land characteristics are no longer considered when land is cleared and now clearance also occurs in neighbouring villages with available lands. These results suggest that the region has finally evolved similarly to a Malthusian rationale, even if the past dynamics resulted from a complex combination of factors.Finally, we analysed several prospective scenarios to assess the impacts of i) different population evolutions (normal demographic growth, emigrations and demographic regulation), ii) the implementation of protected areas in each village, iii) an intensification of farming systems. Two possible solutions for reducing natural vegetation clearance in the region are discussed: Emigration to other regions or a demographic regulation accompanied with an intensification of agricultural systems. However, the question remains whether such changes can be accomplished rapidly enough to abate the pressing natural vegetation decrease threat and to maintain an acceptable livelihood in the region.

114P - Conquering cardiotoxicity of trastuzumab: A 99Tc radiolabelled bio-distribution study

Background: Overexpression of human epidermal growth factor receptor 2 (HER2) is responsible for approximately 35% of breast cancer cases. A number of approaches have been designed to inhibit overexpressed HER-2 receptors. Inhibiting these overexpressed HER-2 receptors in the breast is desirable. However, this inhibition never happens in isolation. HER-2 pathway in the heart, involved in the regulation of normal cellular metabolism, growth and survival, is also inhibited which leads to serious cardiotoxicity. The research was aimed to design a delivery system for trastuzumab which can bypass the cardiotoxicity without compromising the desired therapeutic action at the breast. Methods: PEGylated liposomes of trastuzumab were formulated by lipid layer hydration technique. To ensure the maximum entrapment, different ratios of trastuzumab and lipids were utilised. The optimised formulation with maximum entrapment was labelled with 99 m Tc. In vivo biodistribution study was performed in rats xenografted with MCF-7 breast cancer cell lines to compare the biodistribution in heart and the breast tissues. Results: Percent entrapment efficiency (%EE) of trastuzumab in liposomes was found to be 79.7% ± 8.2%. The labelling efficiency was almost the same up to 90 min after incubation for trastuzumab and liposomes. Less than 2% of radioactivity was dissociated after 6 hours incubation in the saline which indicates the suitability of the complex for its in vivo use. Results of biodistribution revealed that in the case of 99mTc-liposomes, the radioactivity present in the cancerous breast was greater at all timepoints compared to that in the heart Conclusions: PEGylated liposomes seem to be a promising delivery system to overcome the cardiomyopathy associated with trastuzumab. Pegylated lipid system spends less time in the heart due to lymphatic drainage. And whatever time it spends in the heart, it is shielded by the lipid barrier. Legal entity responsible for the study: VNS Institutional Ethical Committee Funding: None Disclosure: All authors have declared no conflicts of interest.

Variation in Akt protein kinases in human populations.

The three Akt kinases are related proteins that are essential for normal growth and metabolic regulation and are implicated as key signaling mediators in many physiological and pathophysiological processes. Each Akt is activated by common biochemical signals that act downstream of growth factor and hormone receptors via phosphatidylinositol-3 kinase, and each controls several downstream pathways. The importance of Akt actions in human physiology is strengthened by the rarity of modifying mutations in their genes and by the devastating impact caused by these mutations on growth and development and in disorders such as cancer. Recent advances in genomics present unique opportunities for enhancing our understanding of human physiology and disease predisposition through the lens of population genetics, and the availability of DNA sequence data from 60,706 people in the Exome Aggregation Consortium has prompted this analysis. Results reveal a cohort of potential missense and other alterations in the coding regions of each AKT gene, but with nearly all changes being uncommon. The total number of different alleles per gene varied over an approximately threefold range, from 52 for AKT3 to 158 for AKT2, with variants distributed throughout all Akt protein domains. Previously characterized disease-causing mutations were found rarely in the general population. In contrast, a fairly prevalent amino acid substitution in AKT2 appears to be linked to increased predisposition for type 2 diabetes. Further analysis of variant Akt molecules as identified here will provide opportunities to understand the intricacies of Akt signaling and actions at a population level in human physiology and pathology.

Different expression levels of DLK1 inversely modulate the oncogenic potential of human MDA-MB-231 breast cancer cells through inhibition of NOTCH1 signaling.

NOTCH receptors participate in cancer cell proliferation and survival. Accumulated evidence indicates that, depending on the cellular context, these receptors can function as oncogenes or as tumor-suppressor genes. The epidermal growth factor-like protein delta-like homolog (DLK)1 acts as a NOTCH inhibitor and is involved in the regulation of normal and tumoral growth. In this work, we focused on the role of DLK1 in the control of breast cancer cell growth, a tumor type in which NOTCH receptors have been shown to play both opposite roles. We found that human DLK1 inhibits NOTCH signaling in MDA-MB-231 breast cancer cells. The proliferation rate and invasion capabilities of these cells depended on the level of NOTCH activation and signaling, as regulated by DLK1. High levels of DLK1 expression led to a significant decrease in NOTCH signaling, which was associated with a decrease in breast cancer cell proliferation and invasion. On the contrary, lower levels of NOTCH inhibition, caused by lower levels of DLK1 overexpression, led to enhanced in vitro MDA-MB-231 cell invasion, and to both in vitro and in vivo increased cell proliferation. The data presented in this work suggest that a fine regulation of NOTCH signaling plays an important role in the control of breast cancer cell proliferation and invasion.-Nueda, M.-L., Naranjo, A.-I., Baladrón V., Laborda, J. Different expression levels of DLK1 inversely modulate the oncogenic potential of human MDA-MB-231 breast cancer cells through inhibition of NOTCH1 signaling.

Effect of nonsurgical periodontal therapy on thyroid stimulating hormone in hypothyroid patients with periodontal diseases

The endocrine and the immune system demonstrate a mutual relationship under pathophysiologic conditions. Thyroid hormone plays an important role in the regulation of normal growth and development. Although there is proven bidirectional influence of systemic diseases on periodontium, there are fewer studies on the effect of periodontal therapy on the hormone levels. This study aims to assess the effect of nonsurgical periodontal therapy (NSPT) on serum thyroid stimulating hormone (TSH) levels in hypothyroid patients with periodontal diseases. A total of 30 randomly chosen subjects of which 15 known hypothyroidism patients (13 females and 2 males) who were under medication for the same and 15 healthy individuals were enrolled into the study. Clinical parameters and serum TSH levels were recorded at baseline in both the groups, whereas TSH levels were recorded again at 3 months after NSPT in hypothyroid patients. Intergroup comparison was carried out by Tukey Kramer multiple comparisons test and the difference in variables was analyzed using one-way analysis of variance. Mean values of TSH in hypothyroid patients 3.48 ± 1.41 μIU/ml showed significant reduction to 2.31 ± 1.24 μIU/ml (P ≤ 0.05) at 3 months follow up of NSPT. Clinical parameters improved significantly in both the groups after NSPT (P ≤ 0.05). Alveolar bone loss was greater in hypothyroid patients than the control group at baseline. NSPT plays a major role in improving periodontal conditions by reducing inflammatory markers and thereby influencing the thyroid hormone. Thus, immune system serves as an important link between thyroid dysfunction and periodontal diseases.

Helicobacter pylori as an oncogenic pathogen, revisited.

Gastric cancer is an inflammation-associated malignancy aetiologically related to infection with the bacterium, Helicobacter pylori, which is considered a necessary but insufficient cause. Unless treated, H. pylori causes life-long acute and chronic gastric inflammation resulting in progressive gastric mucosal damage that may result in gastric cancer. The rate of progression from superficial gastritis, to an atrophic metaplastic mucosa, and ultimately to cancer relates to the virulence of the infecting H. pylori as well as host and environmental factors. H. pylori virulence is a reflection of its propensity to cause severe gastric inflammation. Both mucosal inflammation and H. pylori can cause host genomic instability, including dysregulation of DNA mismatch repair, stimulation of expression of activation-induced cytidine deaminase, abnormal DNA methylation and dysregulation of micro RNAs, which may result in an accumulation of mutations and loss of normal regulation of cell growth. The difference in cancer risk between the most and least virulent H. pylori strain is only approximately 2-fold. Overall, none of the putative virulence factors identified to date have proved to be disease-specific. The presence, severity, extent and duration of inflammation appear to be the most important factors and current evidence suggests that any host, environmental or bacterial factor that reliably enhances the inflammatory response to the H. pylori infection increases the risk of gastric cancer.

Somatic overgrowth disorders of the PI3K/AKT/mTOR pathway & therapeutic strategies.

The phosphatidylinositol-3-kinase (PI3K)/AKT/mTOR signaling pathway plays an essential role in regulation of normal cell growth, metabolism, and survival. Somatic activating mutations in the PI3K/AKT/mTOR pathway are among the most common mutations identified in cancer, and have been shown to cause a spectrum of overgrowth syndromes including PIK3CA-Related Overgrowth Spectrum, Proteus syndrome, and brain overgrowth conditions. Clinical findings in these disorders may be isolated or multiple, including sporadic or mosaic overgrowth (adipose, skeletal, muscle, brain, vascular, or lymphatic), and skin abnormalities (including epidermal nevi, hyper-, and hypopigmented lesions), and have the potential risk of tumorigenesis. Key negative regulators of the PI3K-AKT signaling pathway include PTEN and TSC1/TSC2 and germline loss-of function mutations of these genes are established to cause PTEN Hamartoma Tumor Syndrome and Tuberous Sclerosis Complex. Mosaic forms of these conditions lead to increased activation of PI3K and mTOR at affected sites and there is phenotypic overlap between these conditions. All are associated with significant morbidity with limited options for treatment other than symptomatic therapies and surgeries. As dysregulation of the PI3K/AKT/mTOR pathway has been implicated in cancer, several small molecule inhibitors targeting different components of the PI3K/AKT/mTOR signaling pathway are under clinical investigation. The development of these therapies brings closer the prospect of targeting treatment for somatic PI3K/AKT/mTOR-related overgrowth syndromes. This review describes the clinical findings, gene function and pathogenesis of these mosaic overgrowth syndromes, and presents existing and future treatment strategies to reduce or prevent associated complications of these disorders. © 2016 Wiley Periodicals, Inc.

Targeting the mTOR Pathway in Leukemia.

Optimal function of multiple intracellular signaling pathways is essential for normal regulation of cellular transcription, translation, growth, proliferation, and survival. Dysregulation or aberrant activation of such cascades can lead to inappropriate cell survival and abnormal cell proliferation in leukemia. Successful treatment of chronic myeloid leukemia (CML) with tyrosine kinase inhibitors targeting the BCR-ABL fusion gene is a prime example of effectively inhibiting intracellular signaling cascades. However, even in these patients resistance can develop via emergence of mutations or feedback activation of other pathways that cause refractory disease. Constitutive activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway has been observed in different types of leukemia, including CML, acute myeloid leukemia, and acute lymphoblastic leukemia. Abnormal mTOR activity may contribute to chemotherapy resistance, while it may also be effectively targeted via molecular means and/or development of specific pharmacological inhibitors. This review discusses the role of PI3K/Akt/mTOR dysre-gulation in leukemia and summarizes the emergence of preliminary data for the development of novel therapeutic approaches. J. Cell. Biochem. 117: 1745-1752, 2016. © 2016 Wiley Periodicals, Inc.

Polyamines regulate cell growth and cellular methylglyoxal in high-glucose medium independently of intracellular glutathione.

Polyamines can presumably inhibit protein glycation, when associated with the methylglyoxal inevitably produced during glycolysis. Herein, we hypothesized a nonenzymatic interaction between putrescine and methylglyoxal in putrescine-deficient or -overexpressing Dictyostelium cells in high-glucose medium, which can control methylglyoxal production. Putrescine was essentially required for growth rescue accompanying methylglyoxal detoxification when cells underwent growth defect and cell cycle G1-arrest when supplemented with high glucose. Furthermore, methylglyoxal regulation by putrescine seemed to be a parallel pathway independent of the changes in cellular glutathione content in high-glucose medium. Consequently, we suggest that Dictyostelium cells need polyamines for normal growth and cellular methylglyoxal regulation.

Dexamethasone Regulates EphA5, a Potential Inhibitory Factor with Osteogenic Capability of Human Bone Marrow Stromal Cells.

We previously demonstrated the importance of quality management procedures for the handling of human bone marrow stromal cells (hBMSCs) and provided evidence for the existence of osteogenic inhibitor molecules in BMSCs. One candidate inhibitor is the ephrin type-A receptor 5 (EphA5), which is expressed in hBMSCs and upregulated during long-term culture. In this study, forced expression of EphA5 diminished the expression of osteoblast phenotypic markers. Downregulation of endogenous EphA5 by dexamethasone treatment promoted osteoblast marker expression. EphA5 could be involved in the normal growth regulation of BMSCs and could be a potential marker for replicative senescence. Although Eph forward signaling stimulated by ephrin-B-Fc promoted the expression of ALP mRNA in BMSCs, exogenous addition of EphA5-Fc did not affect the ALP level. The mechanism underlying the silencing of EphA5 in early cultures remains unclear. EphA5 promoter was barely methylated in hBMSCs while histone deacetylation could partially suppress EphA5 expression in early-passage cultures. In repeatedly passaged cultures, the upregulation of EphA5 independent of methylation could competitively inhibit osteogenic signal transduction pathways such as EphB forward signaling. Elucidation of the potential inhibitory function of EphA5 in hBMSCs may provide an alternative approach for lineage differentiation in cell therapy strategies and regenerative medicine.

Abstract LB-A20: Novel Dual Oncogenic Target Inhibitor against Allosteric Mitogen-Activated Protein Kinase (MEK1) and Phosphatidylinositol 3-Kinase (PI3K)

Abstract The Ras/MEK/ERK and PI3K/Akt/mTor pathways play a central role in the regulation of normal cell growth, division and differentiation. Dysregulation of these signaling pathways driven by oncogenic mutations/activation leading to elevated kinase activity has been demonstrated in many human cancers. Strong evidence suggests the existence of a feedback loop with crosstalk between these two signaling cascades leading to redundancy in survival pathways. Consequently, monotherapy targeting a single cascade may be insufficient to induce tumor cell death due to drug resistance mechanisms. Initial biological results are presented from a series of novel small molecule kinase inhibitors specifically designed to simultaneously target both MEK1 and PI3K. Structural analogs of the ATP-competitive PI3K inhibitor ZSTK474 and the ATP-noncompetitive class of MEK inhibitors PD0325901, respectively, were covalently combined to provide single compound dual inhibitors. Inhibitors showed potent MEK1 inhibition (0.015 < IC50 (nM) < 56.7) and PI3K inhibition (54 < IC50 (nM) < 341) in tumor cell culture inhibition assays. Cellular efficacy studies were accomplished and revealed several of the designed inhibitor analogs demonstrated near complete inhibition of MEK1 and PI3K kinase activity by western blot analysis in A549 lung adenocarcinoma and D54 glioma cell lines at concentrations as low as 5 μM. Inhibitors also produced dose-dependent decreases in cell viability in these cell lines similar to that displayed with the combined administration of equivalent doses of ZSTK474 and PD0325901. In vivo evaluation of selected compounds was undertaken to evaluate oral bioavailability and activity. In preliminary studies conducted in D54 glioma tumor bearing mice, a 95% and 67% inhibition of tumor ERK1/2 and Akt phosphorylation, respectively, was found at 2 h post-administration as determined by western blot analysis. This study reveals that dual targeted small molecules designed to inhibit MEK1/PI3K pathways were effective in target modulation in intact mouse tumor models. Overall, this study details a highly novel approach for combined MEK1/PI3K inhibition with first in vivo results. Citation Format: Brian D. Ross, Hao Hong, Hanxiao Wang, Charles A, Nino, Marcian E. Van Dort. Novel Dual Oncogenic Target Inhibitor against Allosteric Mitogen-Activated Protein Kinase (MEK1) and Phosphatidylinositol 3-Kinase (PI3K). [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr LB-A20.

Pregnancy Augments G Protein Estrogen Receptor (GPER) Induced Vasodilation in Rat Uterine Arteries via the Nitric Oxide - cGMP Signaling Pathway.

BackgroundThe regulation of vascular tone in the uterine circulation is a key determinant of appropriate uteroplacental blood perfusion and successful pregnancy outcome. Estrogens, which increase in the maternal circulation throughout pregnancy, can exert acute vasodilatory actions. Recently a third estrogen receptor named GPER (G protein-coupled estrogen receptor) was identified and, although several studies have shown vasodilatory effects in several vascular beds, nothing is known about its role in the uterine vasculature.AimThe aim of this study was to determine the function of GPER in uterine arteries mainly during pregnancy. Uterine arteries were isolated from nonpregnant and pregnant rats.MethodsVessels were contracted with phenylephrine and then incubated with incremental doses (10−12–10−5 M) of the selective GPER agonist G1.ResultsG1 induced a dose-dependent vasodilation which was: 1) significantly increased in pregnancy, 2) endothelium-dependent, 3) primarily mediated by NO/cGMP pathway and 4) unaffected by BKca channel inhibition.ConclusionThis is the first study to show the potential importance of GPER signaling in reducing uterine vascular tone during pregnancy. GPER may therefore play a previously unrecognized role in the regulation of uteroplacental blood flow and normal fetus growth.

Clinical prospects of IGF-signaling system components study in ovarian cancer patients.

Among various auto/paracrine growth-regulating signaling pathways an important role belongs to that of insulin-like growth factors (IGFs) and insulin. IGF-signaling system is actively involved in the regulation of both normal ovarian function and ovarian tumor growth. On the one hand, all members of this system are expressed in malignant ovarian epithelial cells, and the prognostic significance of this expression has been revealed for some of them in ovarian cancer patients in several studies. On the other hand, circulating IGFs/IGFBPs levels have not been undoubtedly associated with ovarian cancer risk or disease progression, but some of them can be regarded as supplementary serological ovarian cancer markers. An important route to the clinical application of IGF-signaling system studies in ovarian cancer is the growing possibility of using specific molecular targeted agents to suppress its growth-stimulating and other activities. However, the introduction of such agents to practical oncology has met serious problems, with the main difficulties resulting from the absence of reliable predictive molecular markers and metabolic side effects due to the tight connection between IGF-signaling and insulin-regulated processes. The prognostic and diagnostic values of various IGF system components and the current state of corresponding molecular targeted therapies development for ovarian cancer are reviewed.

Whole genome and transcriptome analysis of a novel AML cell line with a normal karyotype

Acute myeloid leukemia (AML) occurs when hematopoietic progenitor cells acquire genetic defects blocking the regulation of normal growth and differentiation. Although recurrent translocations have been identified in AML, almost half of adult AML patients present with a normal karyotype (NK-AML). While cell line models exist to study AML, they frequently have abnormal/unstable karyotypes, while primary cells from NK-AML patients are difficult to maintain in vitro. Here we provide a thorough molecular characterization of a recently established cell line, CG-SH, which has normal cytogenetics, representing a useful new model for NK-AML. Using high-throughput DNA sequencing, we first defined the genetic background of this cell line. In addition to identifying potentially deleterious SNVs in genes relevant to AML, we also found insertions in both GATA2 and EZH2, two genes previously linked to AML. We further characterized the growth of this model system in vitro with a cytokine mix that promotes faster cell growth. We assessed gene expression changes after the addition of cytokines to the culture media and found differential expression in genes implicated in proliferation, apoptosis and differentiation. Our results provide a detailed molecular characterization of genetic defects in this cell line derived from an NK-AML patient.

YAP-mediated induction of monoacylglycerol lipase restrains oncogenic transformation

The Hippo pathway is an evolutionarily conserved regulator of normal and oncogenic growth. Engagement of Hippo pathway signaling results in the inactivation of the transcriptional coactivator YAP by preventing its nuclear entry. The mechanisms underlying the oncogenic properties of YAP remain incompletely understood. Here we find that although the transactivation (TA) domain of YAP mediates YAP-dependent gene expression, it serves as an inhibitor of YAP-mediated anchorage-independent growth. We identify monoacylglycerol lipase (MAGL) as a YAP transcriptional target and an inhibitor of anchorage-dependent cell growth. Significantly, knockdown of MAGL expression leads to the augmentation of YAP-dependent cell transformation. Our results identify MAGL as a transcriptional target of YAP that restrains YAP-mediated cellular transformation.

Thyrocyte-Specific Dicer1 Deficiency Alters Thyroid Follicular Organization and Prevents Goiter Development

MicroRNAs (miRNAs) are important regulators of posttranscriptional gene expression and involved in embryonic development, regulation of cell differentiation, and growth. Dicer1 is a key enzyme in the maturation process of functional miRNAs. However, miRNA-mediated regulation of normal thyroid function and growth is largely unknown. To understand the role of miRNAs in the thyroid, we generated constitutive and tamoxifen-inducible, thyrocyte-specific Dicer1 knockout mice. The mice with perinatal Dicer1 deletion (cTgDcrKO) showed impaired follicular organization, increased fibrosis, and accumulation of adipocytes in the thyroid. Similar histological changes were observed in tamoxifen-induced adult Dicer1-deficient mice (iTgDcrKO). The thyroid phenotype in both knockout (KO) lines was associated with significantly down-regulated mRNA expression of thyroid transcription factor 1 (Ttf-1/Nkx2-1), thyroid peroxidase, and thyroglobulin (Tg) and up-regulated expression of genes involved in Tgf-β signaling. Furthermore, in cTgDcrKO mice, which developed mild hypothyroidism, the protein expression of Nkx2-1, thyroglobulin, Paired box 8, and TSH receptor were clearly down-regulated compared with controls. Despite similar down-regulation of Dicer1 in cTgDcrKO and iTgDcrKO compared with controls, Dicer1 deletion in adult mice thyrocytes did not lead to acute hypothyroidism. No significant differences in thyroid weights between cTgDcrKO, iTgDcrKO, and controls were observed. However, a goitrogenic diet induced a 4-fold increase in thyroid weight in control animals, whereas it had no effect on iTgDcrKO thyroids. In summary, Dicer1 deficiency in thyrocytes is associated with intrathyroid fibrosis, adipogenesis, and enhanced expression of Tgf-β signaling genes. Furthermore, our data indicate that Dicer1 is required for thyroid follicular organization, thyrocyte differentiation, and goiter development.

Human placental growth hormone: A potential new biomarker in gestational trophoblastic disease

ObjectivesGestational trophoblastic disease (GTD) involves a spectrum of abnormal proliferations arising from the placental villous trophoblast. Although the incidence is low, a biomarker with short serum half-life would be a major clinical advance to monitor surgical and medical treatment reducing the socioeconomic burden of multiple control visits as well as patient's anxiety.Placental growth hormone (hGH-V) plays an important role in the regulation of normal placental growth and has shown angiogenic effects.We aimed to determine by immunohistochemistry (IHC) whether hGH-V is expressed in GTD and whether it can be detected in the patient's blood for potential monitoring of surgical or medical treatment procedures. MethodsTissue and sera were collected from women undergoing treatment for GTD in a tertiary care university hospital. We evaluated partial and complete hydatidiform moles, invasive moles and choriocarcinoma, n=16.Trophoblast specimens were examined by a newly developed IHC set-up for hGH-V in addition to gross morphologic and histopathological examination. Serum samples were analyzed by a highly sensitive hGH-V specific immunoassay. ResultshGH-V was localized in all entities of GTD to the syncytiotrophoblast by immunohistochemistry. Serum hGH-V was detected for the first time in GTD and was present in a high percentage of all analyzed entities. ConclusionshGH-V can be detected in all entities of GTD by IHC as well as by serum analysis and may therefore serve as a novel biomarker for the disease. Its clinical utility in diagnosis of GTD and monitoring surgical or medical treatment needs to be determined in further studies.

77P - A Powerful Drug-Delivery System in Reducing Cardio-Toxicity of Trastuzumab: A Bio-Distribution Study Using 99TC Radiolabeling Technique

Objective: The research work is based on the concept of targeted drug delivery of Trastuzumab, a monoclonal antibody against breast cancer, using PEGylated liposomes. Almost one-third cases of breast cancers are associated with over-expression of human epidermal growth factor receptor 2 (HER2). Trastuzumab acts by interfering with HER-2 receptors in the breast. However, HER-2 pathway plays a significant role in heart too, where it is involved in the regulation of normal cellular metabolism, growth and survival. The most significant toxicity associated with trastuzumab is cardiomyopathy ranging from subclinical decreases in left ventricular ejection fraction (LVEF) to cardiac failure manifesting as congestive heart failure (CHF). The risk is greatest when administered concurrently with anthracyclines. Inhibition of HER-2 receptors in the breast is desirable for its therapeutic benefit but their blockage in the heart is related to its associated cardio-toxicity. Methods: Trastuzumab was incorporated into PEGylated liposomes by lipid-layer hydration technique using different ratios of lipids. Accordingly, the formulation with maximum entrapment of the drug was selected to investigate the biodistribution of trastuzumab loaded liposomes and compared to free trastuzumab in rats xenografted with human MCF-7 breast cancer cell lines. For the purpose of biodistribution study, trastuzumab was radiolabelled with 99mTc. Results: Percent entrapment efficiency (%EE) of the liposomes was found to be 65.7 ± 4.6%. The labelling efficiency was almost same upto1 h after incubation for trastuzumab and liposomes. Less than 2% to 8% radioactivity was dissociated after 6 hours incubation in the saline which indicates the suitability of the complex for its in vivo use. Results of biodistribution revealed that in the case of 99mTc-liposomes, the radioactivity present in the cancerous breast was more at all the time points compared to other organs. Conclusion: PEGylated liposomes can definitely serve as a potential tool to overcome the cardiomyopathy associated to trastuzumab. Retention time of liposomes is less at the heart due to lymphatic drainage and at that time too, the drug is shielded by lipid barrier. Disclosure: All authors have declared no conflicts of interest.

Polyamine Alterations in Isolated Zucchini Cotyledons Grown in Presence of Cytokinins and Cu<sup>2+</sup>

Polyamines are small nitrogen-containing organic molecules, which are widely distributed in plants. They are involved in the regulation of normal plant growth and developmental processes. In this study we examined the role of polyamines on the growth of Cucurbita pepo L.(zucchini) cotyledons incubated on solutions of different types of cytokinins (BA—N6-benzylaminopurine or 4PU-30—N1-(2-chloro-4-pyridyl)-N2-phenylurea) and copper in excess. We found that endogenous polyamines, and mainly the conjugated fraction, are involved in the cell division processes of isolated zucchini cotyledons and their changes are related to the specific action of the used growth regulating factors.