BackgroundPancreatic ductal adenocarcinoma (PDAC) is the fourth most common cause of cancer related death. It is lethal in nearly all patients, due to an almost complete chemoresistance. Most if not all drugs that pass preclinical tests successfully, fail miserably in the patient. This raises the question whether traditional 2D cell culture is the correct tool for drug screening. The objective of this study is to develop a simple, high-throughput 3D model of human PDAC cell lines, and to explore mechanisms underlying the transition from 2D to 3D that might be responsible for chemoresistance.MethodsSeveral established human PDAC and a KPC mouse cell lines were tested, whereby Panc-1 was studied in more detail. 3D spheroid formation was facilitated with methylcellulose. Spheroids were studied morphologically, electron microscopically and by qRT-PCR for selected matrix genes, related factors and miRNA. Metabolic studies were performed, and a panel of novel drugs was tested against gemcitabine.ResultsComparing 3D to 2D cell culture, matrix proteins were significantly increased as were lumican, SNED1, DARP32, and miR-146a. Cell metabolism in 3D was shifted towards glycolysis. All drugs tested were less effective in 3D, except for allicin, MT100 and AX, which demonstrated effect.ConclusionsWe developed a high-throughput 3D cell culture drug screening system for pancreatic cancer, which displays a strongly increased chemoresistance. Features associated to the 3D cell model are increased expression of matrix proteins and miRNA as well as stromal markers such as PPP1R1B and SNED1. This is supporting the concept of cell adhesion mediated drug resistance.

AB, Novum, Huddinge; Sweden). Clinical and biochemical implications of low thyroid hormone levels (total and free forms) in euthyroid patients with chronic kidney disease. J Intern Med 2007; 262: 690-701.Objectives. In this study, we explore the associations of decreased thyroid hormone levels with inflammation, wasting and survival in biochemically euthyroid patients with end-stage renal disease (ESRD).Design. After exclusion of 23 patients with thyroidstimulating hormone (TSH) values outside the normal range (0.1-4.5 mIU L )1 ), 187 clinically and biochemically euthyroid incident ESRD stage 5 patients starting dialysis were followed for a median of 20 (range 1-60) months. Measurements of total and free forms of thyroid hormones, s-albumin, hs-CRP, interleukin (IL)-6, vascular adhesion molecule (VCAM)-1 and insulin-like growth factor 1 (IGF-1) were performed at baseline.Results. In this population, 17 out of 210 patients (8%) were defined as subclinically hypothyroid. Multivariate analysis, according to receiver operating characteristic (ROC) curves, showed that mortality was best predicted by total triiodothyronine (T3). When using the cut-off levels derived from ROC, low T3 levels were associated with increased inflammation (higher hs-CRP, IL-6 and VCAM-1) and lower concentration of both s-albumin and IGF-1. Finally, low T3 but not low free triiodothyronine was associated with worse all-cause (Likelihood ratio = 45.4; P < 0.0001) and cardiovascular mortality (Likelihood ratio = 47.8; P < 0.0001) after adjustment for confounding factors.Conclusion. This study showed that low T3 levels are independent predictors of all-cause and also cardiovascular disease mortality in biochemically euthyroid patients, perhaps due to an intimate association with inflammation. Based on these results, the use of T3 levels in studies assessing the relationship between thyroid dysfunction and mortality risk is recommended.

Atherosclerotic cardiovascular disease is a major problem despite the availability of drugs that influence major risk factors. New treatments are needed, and there is growing interest in therapies that may have multiple actions. Thyroid hormone modulates several cardiovascular risk factors and delays atherosclerosis progression in humans. However, use of thyroid hormone is limited by side effects, especially in the heart. To overcome this limitation, pharmacologically selective thyromimetics that mimic metabolic effects of thyroid hormone and bypass side effects are under development. In animal models, such thyromimetics have been shown to stimulate cholesterol elimination through LDL and HDL pathways and decrease body weight without eliciting side effects. We report here studies on a selective thyromimetic [KB2115; (3-[[3,5-dibromo-4-[4-hydroxy-3-(1-methylethyl)-phenoxy]-phenyl]-amino]-3-oxopropanoic acid)] in hu-mans. In moderately overweight and hypercholesterolemic subjects KB2115 was found to be safe and well tolerated and elicited up to a 40% lowering of total and LDL cholesterol after 14 days of treatment. Bile acid synthesis was stimulated without evidence of increased cholesterol production, indicating that KB2115 induced net cholesterol excretion. KB2115 did not provoke detectable effects on the heart, suggesting that the pharmacological selectivity observed in animal models translates to humans. Thus, selective thyromimetics deserve further study as agents to treat dyslipidemia and other risk factors for atherosclerosis.

Coordinated regulation of bile acid biosynthesis, the predominant pathway for hepatic cholesterol catabolism, is mediated by few key nuclear receptors including the orphan receptors liver receptor homolog 1 (LRH-1), hepatocyte nuclear factor 4␣ (HNF4␣), small heterodimer partner (SHP), and the bile acid receptor FXR (farnesoid X receptor). Activation of FXR initiates a feedback regulatory loop via induction of SHP, which suppresses LRH-1-and HNF4␣-dependent expression of cholesterol 7␣ hydroxylase (CYP7A1) and sterol 12␣ hydroxylase (CYP8B1), the two major pathway enzymes. Here we dissect the transcriptional network governing bile acid biosynthesis in human liver by identifying GPS2, a stoichiometric subunit of a conserved corepressor complex, as a differential coregulator of CYP7A1 and CYP8B1 expression. Direct interactions of GPS2 with SHP, LRH-1, HNF4␣, and FXR indicate alternative coregulator recruitment strategies to cause differential transcriptional outcomes. In addition, species-specific differences in the regulation of bile acid biosynthesis were uncovered by identifying human CYP8B1 as a direct FXR target gene, which has implications for therapeutic approaches in bile acid-related human disorders.cholesterol 7␣ hydroxylase ͉ sterol 12␣ hydroxylase ͉ farnesoid X receptor ͉ small heterodimer partner B ile acids (BAs) are cholesterol derivatives essential for absorption of dietary lipids and fat-soluble vitamins and maintenance of cholesterol BA homeostasis (1, 2). In humans the major BA biosynthetic pathway is initiated by cholesterol 7␣ hydroxylase (CYP7A1) to produce two primary BAs, cholic acid and chenodeoxycholic acid (CDCA). Sterol 12␣ hydroxylase (CYP8B1) catalyzes the synthesis of cholic acid and determines the ratio of cholic acid to CDCA in the bile (1). In addition to emulsification of dietary lipids, cholic acid and CDCA are ligands for farnesoid X receptor (FXR/NR1H4) (3-5). Ligandbound FXR regulates a number of target genes involving BA transport and metabolism (6). BAs also feedback-regulate BA biosynthesis, where activated FXR induces small heterodimer partner (SHP/NR0B2) gene expression, and SHP in turn inhibits liver receptor homolog 1 (LRH-1/NR5A2) or hepatocyte nuclear factor 4␣ (HNF4␣/NR2A1) activities on the BA response elements (BAREs) of CYP7A1 and CYP8B1 promoters (7-10). BAs can also act via FXR-independent pathways that use PKC (11) and JNK signaling (12, 13) to suppress HNF4␣-mediated expression of human CYP8B1 (hCYP8B1) (10,11,14). Although the physiological role of SHP in BA biosynthesis is well documented, mechanistic details of repression by SHP remain unclear. Recent studies indicate that SHP may repress its targets (i) via direct binding and blocking the coactivator interaction interface of its target nuclear receptors (NRs), (ii) by antagonizing CREB binding protein (CBP)/p300-dependent coactivator functions on NRs via recruitment of a coinhibitor protein like EID1, and (iii) by recruiting corepressor complexes that include histone deacetylases (HDAC) 1, 3, and 6, Sin3A...

A novel signaling pathway for mediation of ␤ 3 -adrenergic activation of the mitogen-activated protein kinases Erk1/2 (associated with proliferation, differentiation, and apoptosis) has recently been proposed, which implies mediation via constitutively coupled G i -proteins and G␤␥-subunits, distinct from the classical cAMP pathway of ␤-adrenergic stimulation. To verify the significance of this pathway in cells in primary cultures that entopically express ␤ 3 -adrenoreceptors, we examined the functionality of this pathway in cultured brown adipocytes. Norepinephrine activated Erk1/2 via both ␤ 3 receptors and ␣ 1 receptors but not via ␣ 2 receptors. Forskolin induced Erk1/2 activation similarly to ␤ 3 activation, indicating cAMP-mediation; this induction could be inhibited with H89, implying protein kinase A mediation. The G i -pathway was functional in these cells, as pertussis toxin increased agonist-induced cAMP accumulation. However, pertussis toxin was unable to affect adrenergically induced Erk1/2 activation. Also, wortmannin was without effect, implying that G␤␥ activation of the phosphatidylinositol 3-kinase pathway was not involved. PP1/2, which inhibits Src, abolished both ␤ 3 -and ␣ 1 -induced Erk1/2 activation. Thus, the proposed novel G i pathway for ␤ 3 mediation is not universal, because it is not functional in the untransformed primary cell culture system with entopically expressed ␤ 3 receptors examined here. Here, the ␤ 3 signal is mediated classically via cAMP/protein kinase A. ␤ 3 and ␣ 1 signals converge at Src, which thus mediates Erk1/2 activation in both pathways.