Milena Pariali

CNS Myelin and Sertoli Cell Tight Junction Strands Are Absent in Osp/Claudin-11 Null Mice

Oligodendrocyte-specific protein (OSP)/claudin-11 is a recently identified transmembrane protein found in CNS myelin and testis with unknown function. Herein we demonstrate that Osp null mice exhibit both neurological and reproductive deficits: CNS nerve conduction is slowed, hindlimb weakness is conspicuous, and males are sterile. Freeze fracture reveals that tight junction intramembranous strands are absent in CNS myelin and between Sertoli cells of mutant mice. Our results demonstrate that OSP is the mediator of parallel-array tight junction strands and distinguishes this protein from other intrinsic membrane proteins in tight junctions. These novel results provide direct evidence of the pivotal role of the claudin family in generating the paracellular physical barrier of tight junctions necessary for spermatogenesis and normal CNS function.

The basal-like breast carcinoma phenotype is regulated by SLUG gene expression.

Basal‐like breast carcinoma is an aggressive form of breast cancer, characterized by the absence of oestrogen receptor and HER2 expression, the presence of cytokeratin 5 and epidermal growth factor receptor expression, and by the up‐regulation of stem cell regulatory genes. We show here that tumour tissues expressing high levels of SLUG mRNA show a basal‐like breast carcinoma phenotype and that such tumours also express high levels of stem cell‐regulatory genes, ie CD133, Bmi1. Further, we show that stem/progenitor cells, isolated from ductal breast carcinoma and from normal mammary gland as mammospheres, express SLUG, CD133, and Bmi1 mRNA and show a phenotype similar to that of basal‐like breast carcinoma. We also report that SLUG expression in tumour tissues correlates with that of the hypoxia survival gene carbonic anhydrase IX. In this regard, we report that the exposure of SLUG‐negative/luminal‐like MCF‐7 cells to a hypoxic environment promotes the onset of the basal‐like breast carcinoma phenotype, together with up‐regulation of the SLUG gene, which in turn blunts oestrogen receptor‐α and boosts carbonic anhydrase IX gene expression. Finally, we show that SLUG expression promotes the invasiveness of MCF‐7 cells exposed to hypoxia and sustains the in vivo aggressiveness of hypoxia‐selected, MCF‐7‐derived cells in xenografts. These data indicate that SLUG gene expression is part of a hypoxia‐induced genetic programme which sets up a basal/stem cell‐like, aggressive phenotype in breast cancer cells. Copyright

High Thymidylate Synthase Expression in Colorectal Cancer with Microsatellite Instability: Implications for Chemotherapeutic Strategies

Colon cancers displaying microsatellite instability (MSI) are clinically less aggressive. Based on in vitro studies and recent clinical data, cancers displaying MSI do not respond to 5-fluorouracil (5-FU). The reasons why MSI tumors are clinically less aggressive and do not respond to 5-FU–based therapies have not been fully elucidated. Purpose: We investigated biomolecular markers in an attempt to explain the different clinical behavior and chemotherapeutic responses of MSI and non-MSI colon cancers. Experimental Design: One hundred ninety-two sporadic colon cancers were tested for MSI with five mononucleotide markers and methylation of the hMLH1 promoter. Slides were stained for thymidylate synthase (TS), p53, MDM2, p21WAF1/CIP1, β-catenin, vascular endothelial growth factor, hMLH1, hMSH2, and hMSH6. Tumors were regarded as having wild-type, functional p53 (Fp53) if reduced expression of p53 and positive MDM2 and p21WAF1/CIP1 expressions were found. Results: Of the cases, 12.5% were MSI-H (at least two markers mutated). Of MSI-H cases, 83.3% were characterized by a complete loss of at least one of the mismatch repair proteins, in particular loss of hMLH1 by promoter hypermethylation. MSI-H colon cancers showed higher expression of TS compared with MSS (no mutated markers)/MSI-L (one mutated marker) colon cancers (66.6% for MSI-H versus 14.8% MSS/MSI-L; P < 0.0001); 20.8% of MSI-H cases showed high expression of the vascular endothelial growth factor, compared with 45.8% MSS/MSI-L colon cancers (P = 0.0005); 45.8% MSI-H cases had Fp53 compared 11.9% MSS/MSI-L cases (P < 0.0001). Conclusions: About 12% of colon cancers display MSI mostly due to lack of hMLH1 resulting from promoter hypermethylation. These tumors have high expression of TS and retain fully functional p53 system. Thus, these data suggest why sporadic hMLH1-defective colon cancers often do not respond to 5-FU.

Gene Expression Profiling in Conjunction with Physiological Rescues of IKKα-null Cells with Wild Type or Mutant IKKα Reveals Distinct Classes of IKKα/NF-κB-dependent Genes

Cellular responses to stress-like stimuli require the IκB kinase (IKK) signalsome (IKKα, IKKβ, and NEMO/IKKγ) to activate NF-κB-dependent genes. IKKβ and NEMO/IKKγ are required to release NF-κB p65/p50 heterodimers from IκBα, resulting in their nuclear migration and sequence-specific DNA binding; but IKKα was found to be dispensable for this initial phase of canonical NF-κB activation. Nevertheless, IKKα(-/-) mouse embryonic fibroblasts (MEFs) fail to express NF-κB targets in response to proinflammatory stimuli, uncovering a nuclear role for IKKα in NF-κB activation. However, it remains unknown whether the global defect in NF-κB-dependent gene expression of IKKα(-/-) cells is caused by the absence of IKKα kinase activity. We show by gene expression profiling that rescue of near physiological levels of wild type IKKα in IKKα(-/-) MEFs globally restores expression of their canonical NF-κB target genes. To prove that the kinase activity of IKKα was required on a genomic scale, the same physiological rescue was performed with a kinase-dead, ATP binding domain IKKα mutant (IKKα(K44M)). Remarkably, the IKKα(K44M) protein rescued ∼28% of these genes, albeit in a largely stimulus-independent manner with the notable exception of several genes that also acquired tumor necrosis factor-α responsiveness. Thus the IKKα-containing signalsome unexpectedly functions in the presence and absence of extracellular signals in both kinase-dependent and -independent modes to differentially modulate the expression of five distinct classes of IKKα/NF-κB-dependent genes.

A conjugate of doxorubicin with lactosaminated albumin enhances the drug concentrations in all the forms of rat hepatocellular carcinomas independently of their differentiation grade

Abstract: Background/Aims: Doxorubicin (DOXO) was coupled to lactosaminated human serum albumin (L‐HSA) in order to enhance the drug concentration in the well differentiated hepatocellular carcinomas (HCCs), which can accumulate L‐HSA through the asialoglycoprotein receptor. In the present experiments we compared the DOXO concentrations produced by this conjugate (L‐HSA–DOXO) and by the uncoupled drug in the well, moderately, and poorly differentiated rat HCCs.

Enhanced uptake of lactosaminated human albumin by rat hepatocarcinomas: implications for an improved chemotherapy of primary liver tumors

Background/Aims: The hepatocyte receptor for asialoglycoproteins (ASGP‐R) internalizes macromolecules exposing galactosyl residues (MEGRs) which can be used as liver‐addressed drug carriers. This receptor was also found on the cells of the large majority of well differentiated hepatocarcinomas (HCCs). The aim of the present experiments was to ascertain whether ASGP‐R of HCCs is functionally active and these tumors can internalize higher quantities of MEGRs than extra‐hepatic tissues.

Extracorporeal Portal Vein Oxygenation Improves Outcome of Acute Liver Failure in Swine

BACKGROUND Portal vein arterialization (PVA) has shown efficacy to treat acute liver failure (ALF) in preclinical studies. The next step is to perform large animal studies that propose a clinically acceptable method of PVA. In this study, we assessed the efficacy of PVA using an extracorporeal device to treat 2 ALF models in swine. MATERIALS AND METHODS The 2 ALF swine models were carbon tetrachloride toxic ALF and subtotal hepatectomy using 8 animals per group. PVA was performed with an extracorporeal device that may be suitable for future clinical studies. Arterial blood was drawn from the iliac artery and delivered into the portal vein for a 6-hour treatment. We analyzed biochemical, blood gas, and histological parameters as well as 1-week survival rates. RESULTS In both models, ALF was successfully achieved. Control group animals deteriorated biochemically, dropping their prothrombin times and increasing the liver enzymes. In contrast, treated animals improved with a survival rate of 75% at 7 days compared with 0% for the former group. CONCLUSIONS PVA using an extracorporeal device was feasible and effective to treat both toxic and resective ALF in swine.

Doxorubicin coupled to lactosaminated albumin: effect of heterogeneity in drug load on conjugate disposition and hepatocellular carcinoma uptake in rats.

Coupling to lactosaminated human albumin (L-HSA) makes doxorubicin (DOXO) an effective drug against chemically induced rat hepatocellular carcinomas (HCCs). In the conjugate there is a large heterogeneity in the number of DOXO molecules bound to one L-HSA molecule. After lyophilization, the molecules with the higher DOXO load form large complexes (C-DOXOL), whereas those with low drug load (C-DOXOS) have the size of the carrier L-HSA. In the present experiments, we demonstrated that in C-DOXOL the molecules are not linked by covalent bonds, but are strongly aggregated probably because of mutual drug-drug interaction between the DOXO residues. In healthy rats and in animals with HCCs which received the same dose (1 microg/g) of DOXO injected in C-DOXOL or in C-DOXOS forms, penetration of the drug in tumors and in tissues was more rapid after administration of the former complex. Three hours after injection of both conjugate forms the intracellular release of DOXO from the carrier was completed. The AUCs from 0.5 to 4h of the levels of the released DOXO in HCCs, surrounding liver and bone marrow of animals injected with C-DOXOL were similar to those calculated in animals given C-DOXOS. This suggests that after administration of the dose of DOXO used in the present experiments the conjugate molecules with lower or higher drug load can exert comparable pharmacological and toxic effects.

Parallel Variations of Insulin-Like Peptide 3 (INSL3) and Antimüllerian Hormone (AMH) in Women With the Polycystic Ovary Syndrome According to Menstrual Cycle Pattern

CONTEXT Antimüllerian hormone (AMH) and insulin-like factor 3 (INSL3) represent ovarian functional markers of granulosa and theca cells, respectively. OBJECTIVE We conducted a prospective study to investigate AMH and INSL3 plasma levels in 3 groups of women with polycystic ovary syndrome (PCOS) classified according to menstrual cyclicity pattern and their relationship with ovarian morphology and hormonal levels. DESIGN AND PARTICIPANTS AMH and INSL3 were measured in a cohort of 57 patients with PCOS, divided into 3 groups according to menstrual status: eumenorrheic (PCOS-E, n = 15), oligomenorrheic (PCOS-O, n = 25), and amenorrheic (PCOS-A, n = 17). Clinical and endocrine characteristics and ovarian morphology were compared among the groups. Twenty-seven age- and weight-matched women without hyperandrogenism were included as controls. RESULTS According to the menstrual pattern, the women with PCOS-A and PCOS-O had higher INSL3 levels with respect to the control women (P = .025 and P = .004, respectively) and higher but not significant INSL3 levels compared with those of the women with PCOS-E. AMH levels were significantly higher in women with PCOS-A and PCOS-O with respect to those in women with PCOS-E (P < .001 and P < .001, respectively) and control women (P < .001 and P < .001, respectively). Interestingly, a significant positive correlation was found between INSL3 and AMH blood levels in all women with PCOS (R = 0.43; P = .002) and across the groups (R = 0.41; P < .001). CONCLUSIONS INSL3 and AMH levels are significantly correlated with each other in women with PCOS, and they are significantly increased, particularly in the presence of amenorrhea and oligomenorrhea. INSL3 and AMH may reflect a dysfunction of PCOS thecal and granulosa cells, which are responsible for the increased androgen production and chronic anovulation of this condition.

Effect of Colic Vein Ligature in Rats with Loperamide-Induced Constipation

Introduction. Medical treatment in chronic constipation is not always successful. Surgery is indicated in unresponsive selected severe cases. This study presents the distal venous colic ligation in rat as a novel surgical approach. Materials and Methods. 16 rats (study group) were evaluated in 3 phases of 6 days each: A (normal conditions), B (loperamide-induced constipation), and C (colic vein legation) and compared with rats treated in phase C with PEG 4,000 (control group). Blood biochemical and physiological parameters, daily fecal water content (FWC), and histological analysis were performed in all study phases. Results. No biochemical and physiological parameters changes were observed. FWC decreased in phase B and increased in phase C in both groups with a grow up to 2.3-fold in study group compared to control (P < 0.0001). Moreover, in study group, a high number of colonic goblet cells were detected (phase C versus phase B: P < 0.001) while no differences were registered in control. Conclusion. By ligature of the colic vein in constipated rats, an increase in FWC and goblet cells higher than in PEG treated rats was detected. The described surgical procedure appeared effective, simple, and safe; further studies in animal models, however, are necessary to assess its clinical applicability.