Overexpression of miR-214-3p in esophageal squamous cancer cells enhances sensitivity to cisplatin by targeting survivin directly and indirectly through CUG-BP1.

Based on its marked overexpression in multiple malignancies and its roles in promoting cell survival and proliferation, survivin is an attractive candidate for targeted therapy. Toward this end, a detailed understanding of the mechanisms regulating survivin expression in different cancer cells will be critical. We have previously shown that the RNA-binding protein (RBP) CUG-BP1 is overexpressed in esophageal cancer cells and post-transcriptionally regulates survivin in these cells. The objective of this study was to investigate the role of microRNAs (miRs) in regulating survivin expression in esophageal cancer cells. Using miR expression profiling analysis, we found that miR-214-3p is one of the most markedly downregulated miRs in two esophageal squamous cancer cell lines compared with esophageal epithelial cells. Interestingly, using miR target prediction programs, both survivin and CUG-BP1 mRNA were found to contain potential binding sites for miR-214-3p. Forced expression of miR-214-3p in esophageal cancer cells leads to a decrease in the mRNA and protein levels of both survivin and CUG-BP1. This effect is due to decreased mRNA stability of both targets. By contrast, silencing miR-214-3p in esophageal epithelial cells leads to an increase in both survivin and CUG-BP1 mRNA and protein. To determine whether the observed effect of miR-214-3p on survivin expression was direct, mediated through CUG-BP1, or both, binding studies utilizing biotin pull-down assays and heterologous luciferase reporter constructs were performed. These demonstrated that the mRNA of survivin and CUG-BP1 each contain two functional miR-214-3p-binding sites as confirmed by mutational analysis. Finally, forced expression of miR-214-3p enhances the sensitivity of esophageal cancer cells to cisplatin-induced apoptosis. This effect is abrogated with rescue expression of survivin or CUG-BP1. These findings suggest that miR-214-3p acts as a tumor suppressor and that its downregulation contributes to chemoresistance in esophageal cancer cells by targeting both survivin and CUG-BP1.

Telomerase and its potential for therapeutic intervention.

Telomerase and telomeres are attractive targets for anticancer therapy. This is supported by the fact that the majority of human cancers express the enzyme telomerase which is essential to maintain their telomere length and thus, to ensure indefinite cell proliferation--a hallmark of cancer. Tumours have relatively shorter telomeres compared to normal cell types, opening the possibility that human cancers may be considerably more susceptible to killing by agents that inhibit telomere replication than normal cells. Advances in the understanding of the regulation of telomerase activity and the telomere structure, as well as the identification of telomerase and telomere associated binding proteins have opened new avenues for therapeutic intervention. Here, we review telomere and telomerase biology and the various approaches which have been developed to inhibit the telomere/telomerase complex over the past decade. They include inhibitors of the enzyme catalytic subunit and RNA component, agents that target telomeres, telomerase vaccines and drugs targeting binding proteins. The emerging role of telomerase in cancer stem cells and the implications for cancer therapy are also discussed.

Telomere uncapping by the G-quadruplex ligand RHPS4 inhibits clonogenic tumour cell growth in vitro and in vivo consistent with a cancer stem cell targeting mechanism.

The pentacyclic acridinium methosulfate salt RHPS4 induces the 3'single-stranded guanine-rich telomeric overhang to fold into a G-quadruplex structure. Stabilisation of the latter is incompatible with an attachment of telomerase to the telomere and thus G-quadruplex ligands can effectively inhibit both the catalytic and capping functions of telomerase. In this study, we examined mechanisms underlying telomere uncapping by RHPS4 in uterus carcinoma cells (UXF1138L) with short telomeres and compared the susceptibility of bulk and clonogenic cancer cells to the G-quadruplex ligand. We show that treatment of UXF1138L cells with RHPS4 leads to the displacement of the telomerase catalytic subunit (hTERT) from the nucleus, induction of telomere-initiated DNA-damage signalling and chromosome fusions. We further report that RHPS4 is more potent against cancer cells that grow as colonies in soft agar than cells growing as monolayers. Human cord blood and HEK293T embryonic kidney cell colony forming units, however, were more resistant to RHPS4. RHPS4-treated UXF1138L xenografts had a decreased clonogenicity, showed loss of nuclear hTERT expression and an induction of mitotic abnormalities compared with controls. Although single-agent RHPS4 had limited in vivo efficacy, a combination of RHPS4 with the mitotic spindle poison Taxol caused tumour remissions and further enhancement of telomere dysfunction.

Lithium and inositol: effects on brain water homeostasis in the rat.

RATIONALE: Since its earliest use in psychiatry, lithium has been known to alter body water homeostasis. Although lithium is also known to decrease the concentration of inositol, an important brain osmolyte, little is known of the effects of lithium on brain water homeostasis. OBJECTIVE: To determine whether lithium alters brain water homeostasis, and, if so, whether the mechanism involves changes in inositol concentration. MATERIALS AND METHODS: Rats were fed regular food or regular food plus lithium chloride for either 11 days or 5 weeks. Brains were dissected and assayed for tissue water by the wet-dry method and for inositol by gas chromatography-mass spectrometry. RESULTS: We found a statistically significant (p=0.05, corrected) 3.1% mean elevation in frontal cortex tissue water in 5-week lithium-fed rats (86.7+/-3.9%), compared to control rats (83.6+/-2.6%). Inositol concentration correlated inversely with percent tissue water (r=-0.50, p=0.003, corrected) in pooled samples of 5-week lithium-fed rats, and was significantly lower in frontal cortex and hippocampus of 5-week lithium-fed rats, compared to controls. Rats fed lithium for 11 days did not differ significantly from controls on either variable. CONCLUSIONS: This is the first report of a lithium-induced increase in brain tissue water. Although the mechanism is unclear, it does not appear to result from changes in brain inositol concentration or blood sodium concentration. This finding may have implications for the therapeutic or toxic effects of lithium on brain, because increased tissue water can augment cell excitability.

Gynaecological and obstetrical morbidity in women with type I von Willebrand disease: results of a patient survey.

Type 1 von Willebrand disease (vWD) is generally regarded clinically as 'mild' and the obstetrical-gynaecological features have not been fully described. We administered a patient questionnaire and provider survey of the medical and quality of life aspects of childbirth and menstruation to 99 type 1 vWD patients and compared the patients presently menstruating (n=81) to a cohort of 150 menstruating females in the general population. The following measurements had a statistically higher proportion in the vWD group: number of tampons/towels used for a typical menstrual cycle (P=0. 002); percentage reporting that clothes are stained by menses (P = 0. 001); past or present history of anaemia (P = 0.001); childbirth-related bleeding (P=0.001); and childbirth-related bleeding necessitating RBC transfusion (P=0.002). Quality of life assessment of the impact of menses in both of the above cohorts was measured by a Likert scale using seven quality of life parameters. Compared to the control group, the vWD patients had a significantly higher score, with P-values of < 0.0001 for each parameter. Hormonal interventions for menorrhagia in the vWD patients were < or = 50% effective. Menorrhagia resulted in red blood cell transfusions in 6% of patients, dilatation and curettage in 17% and hysterectomy in 13%. Despite the common connotation of type 1 vWD as clinically 'mild', childbirth and the monthly challenge to haemostasis presented by menstruation result in a substantial degree of morbidity in females with type 1 vWD. These results support the rationale for ongoing international efforts to increase awareness of vWD as a cause for menorrhagia and to improve the quality of life in females with known vWD.

Asymptomatic hemochromatosis subjects: genotypic and phenotypic profiles.

Screening for hereditary hemochromatosis (HHC) by means of transferrin saturation (TS) levels has been advocated and will identify many patients who are asymptomatic. The purposes of this study were (1) to determine HFE genotypes among asymptomatic HHC patients and correlate this profile with the degree of iron overload and (2) to evaluate the relationship between mobilized iron (mob Fe), age, serum ferritin (SF), and quantitative hepatic iron (QHI) in this population. One hundred twenty-three asymptomatic HHC patients were evaluated; all had quantitative phlebotomy to determine mob Fe and genotyping for C282Y and H63D mutations. Liver biopsies with QHI determinations were performed on 72 of the 123 patients. Of the entire group, 60% were homozygous for C282Y, and 13% were compound heterozygotes (C282Y/H63D). Among asymptomatic patients, the prevalence of homozygous C282Y is lower compared with previous studies that include clinically affected patients. Of those patients with more than 4 g mob Fe, 77% were homozygous C282Y. Asymptomatic patients with lower iron burdens frequently had genotypes other than homozygous C282Y. There was no correlation between age and mob Fe in these patients; however, there was a correlation between mob Fe and both SF (r = 0.68) and QHI (r = 0.75). In conclusion, asymptomatic patients with moderate iron overload had a different genotypic profile than was seen in advanced iron overload. The significance of identifying patients with modest degrees of iron loading, who may not be homozygous for C282Y, must be addressed if routine TS screening is to be implemented. (Blood. 2000;96:3707-3711)

Hematologic neoplasia and the central nervous system.

Central nervous system (CNS) involvement with malignant cells is a well recognized complication of hematologic neoplasms. A number of disorders such as acute lymphoblastic leukemia and high grade lymphoma frequently involve the CNS and prophylactic therapy is advised. Disorders such as acute myeloid leukemia (AML) and multiple myeloma are less likely to be associated with CNS involvement. This series describes three cases of CNS involvement by malignant hematologic disease: myelomatous meningitis, CNS chloromas complicating AML, and primary lymphomatous meningitis.

Prevalence of hereditary hemochromatosis in 16031 primary care patients.

BACKGROUND: Despite evidence from screening studies in northern European populations, the prevalence of hemochromatosis in primary care populations in the United States remains speculative. OBJECTIVE: To establish the feasibility of screening for hemochromatosis and to estimate the prevalence of hemochromatosis in a large primary care population. DESIGN: Cross-sectional prevalence study. SETTING: 22 primary care practices in the Rochester, New York, area. PATIENTS: 16031 ambulatory patients without a previous diagnosis of hemochromatosis. INTERVENTION: Serum transferrin saturation screening tests were offered to all adult patients in participating primary care practices. MEASUREMENTS: Patients with a serum transferrin saturation of 45% or more on initial testing had a serum transferrin saturation test done under fasting conditions and had serum ferritin levels measured. Those who had a fasting serum transferrin saturation of 55% or more and a serum ferritin level of 200 microg/L or more with no other apparent cause were presumed to have hemochromatosis and were offered liver biopsy to confirm the diagnosis. RESULTS: 25 patients had biopsy-proven hemochromatosis; 22 patients met the clinical criteria for hemochromatosis but declined liver biopsy and were classified as having clinically proven hemochromatosis; and 23 patients had a serum transferrin saturation of 55% or more with no identifiable cause, indicating probable hemochromatosis. The prevalence of clinically proven and biopsy-proven hemochromatosis combined was 4.5 per 1000 (95% CI, 3.3 to 5.8 per 1000) in the total sample and 5.4 per 1000 (CI, 4.0 to 7.1 per 1000) in white persons. The prevalence was higher in men than in women (ratio, 1.8:1). CONCLUSIONS: Hemochromatosis is relatively common among white persons. Routine screening of white persons for hemochromatosis should be considered by primary care physicians.

Screening for hemochromatosis in primary care settings.

Interest in including screening for hemochromatosis in the routine medical care of adults has grown in recent years. In March 1997, at a meeting on iron overload at the Centers for Disease Control and Prevention, the directors of four hemochromatosis screening programs described the major challenges that they faced and the lessons that they learned in implementing their programs. Seven issues were consistently described as important challenges: 1) changes in case definitions of hemochromatosis, 2) selection of screening threshold values and identification of false-positive cases, 3) variability and lack of standardization in screening test measurements, 4) physician education, 5) informed consent and concerns about medical and genetic discrimination, 6) patient compliance with screening and therapy, and 7) incidental detection of iron deficiency. The two programs that have been completed report a prevalence of iron overload from hemochromatosis of 4.2 to 4.5 per 1000 persons screened; this is consistent with findings in the recent literature. All programs report that screening is feasible and propose that hemochromatosis be defined by repeated elevated serum transferrin saturation values(with or without DNA test results) rather than by the clinical outcome of excessive iron in tissue. The goal of screening programs is to diagnose iron status disorders, particularly hemochromatosis, before they lead to iron overload and chronic disease states. Further research is needed on the ability of genetic and phenotypic tests to predict the clinical expression of hemochromatosis. The experiences outlined in this report highlight practical issues that need to be addressed when iron status screening for hemochromatosis is implemented. It is hoped that this information will facilitate similar efforts in other health care settings.

Correlation between genotype and phenotype in hereditary hemochromatosis: analysis of 61 cases.

This report assesses the degree of iron overload in a cohort of patients in relationship to the presence or absence of the recently described 845 G-->A (C282Y) and 187 C-->G (H63D) mutations in the HFE (HLA-H) gene. Sixty-one patients with hereditary hemochromatosis diagnosed either with liver biopsy or on clinical grounds were included in this analysis. Forty-one patients were homozygous for C282Y, the genotype considered to be characteristic of hereditary hemochromatosis. At the time of this analysis, 37 of these 41 patients had achieved a state of iron depletion and mobilizable iron was calculated: 19 had less than 4 grams. Twenty-five of these 41 patients had liver biopsies; 4 of these patients had a hepatic iron index less than 1.9. Of the 4 patients with a normal hepatic iron index, 3 had a quantitative hepatic iron of greater than 50 micromol/g dry weight, and one had an inadequate biopsy sample. These findings support our suspicion that individuals may have hereditary hemochromatosis and homozygous C282Y despite relatively low body iron stores. Five patients were compound heterozygotes for C282Y and H63D. Four of these patients underwent liver biopsy; two had a hepatic iron index greater than 1.9. a third patient had a hepatic iron index of 1.3 but a quantitative hepatic iron of 90.6 micromol/g dry weight. All patients were phlebotomized to a state of iron depletion and only one of these patients had a mobilizable iron greater than 4 grams. Three patients were homozygous for H63D; these patients had either a hepatic iron index >1.9 or greater than 4 grams of mobilizable iron. Patients with homozygous H63D and significant iron overload are not well described. Seven patients were heterozygous for either C282Y or H63D; 4 had significant iron overload but three did not. Five patients had no HFE mutations; one of these patients unequivocally has iron overload with a hepatic iron index of 4.4 We conclude that: (1) Identification of HFE mutations will be clinically useful in identifying patients with hereditary hemochromatosis, (2) Patient genotyping will help confirm a diagnosis of hereditary hemochromatosis in some patients with relatively low body iron stores, (3) Significant iron loading can occur in the absence of homozygous C282Y, adding to the evidence that genes other than HFE may be involved in iron loading, and (4) Homozygous H63D can be associated with significant iron overload.

Pharmacokinetics of von Willebrand factor and factor VIIIC in patients with severe von Willebrand disease (type 3 VWD): estimation of the rate of factor VIIIC synthesis. Cooperative Study Groups.

Nine patients (10 infusions) with a confirmed diagnosis of type 3 VWD were infused with von Willebrand factor (human), a preparation of von Willebrand factor (VWF) with a very low factor VIII content. Each patient was infused with one dose of approximately 50 or 100 iu ristocetin cofactor activity (VWF:RiCoF) per kg body weight. Bleeding times were performed during the 24 h period after infusion. Plasma samples were obtained over the 96 h period after infusion and were analysed for factor VIII coagulant activity (FVIIIC), VWF:RiCoF, von Willebrand factor antigen (VWF:Ag), and multimers. The FVIIIC data were analysed by non-linear least-squares analysis assuming constant FVIIIC 'synthesis' and exponential decay. The VWF data were fitted for exponential decay. The average decay rates for FVIIIC, VWF:RiCoF and VWF:Ag were 0.041, 0.061 and 0.056 respectively. The average calculated 'synthesis' rate for FVIIIC was 6.4 u/dl/h. The synthesis of FVIIIC was slightly faster and the decay slightly slower following the infusion of 100 iu VWF:RiCoF/kg than of 50 iu VWF:RiCoF/kg. Correction of the bleeding time was strongly dose dependent. At 4 h post infusion the median bleeding time was 9 min following a dose of 50 iu VWF:RiCoF/kg versus 3 min with a dose of 100 iu VWF:RiCoF/kg. There was no decrease in the bleeding time until the level of VWF:Ag or VWF:RiCoF reached > 100 u/dl.

Fatal thrombotic thrombocytopenic purpura (TTP) presenting concurrently with metastatic multiple endocrine neoplasia (MEN) type I.

A 44-year-old women was treated for hyperparathyroidism resulting from parathyroid hyperplasia. Several months later, following a flu-like episode, she developed fever, confusion, abdominal pain, and diffuse petechiae, with severe thrombocytopenia and hemolytic anemia. She died on the 11th day of hospitalization. At autopsy she had multiple endocrine neoplasia type I, with two islet cell tumors, adrenal adenoma, pituitary adenoma, and bronchial carcinoid with liver metastasis. Florid visceral microthrombi involved arterioles and capillaries of the heart, including the conduction system. Brain, kidney, pancreas, adrenal, and portal areas of the liver were also heavily involved, but thrombi were rare in the liver sinusoids and the lungs. PAS-positive subendothelial deposits were demonstrated. In spite of the disseminated malignancy, the morphologic and laboratory findings were inconsistent with disseminated intravascular coagulation (DIC), and supported the clinical diagnosis of TTP. To the best of our knowledge this is the first report association of TTP with MEN and raises the question of a genetic linkage and/or hormonal interaction.

The effect of dexamethasone on functional properties of HL60 cells during all-trans retinoic acid induced differentiation. Are there implications for the retinoic acid syndrome?

Differentiation therapy for acute promyelocytic leukemia (APL) using all-trans-retinoic acid (ATRA) has improved the prognosis of the disease. ATRA therapy also causes a newly recognized clinical syndrome, the "retinoic acid syndrome" (RAS), which can be successfully managed with dexamethasone. Because aberrant function of maturing leukemic granulocytes may cause this syndrome, and because dexamethasone is useful clinically, we studied functional properties of maturing HL60 cells cultured in the presence and absence of dexamethasone. HL60 cells were cultured for 4 days with ATRA and studied daily to determine acquisition of mature neutrophil-like properties including phagocytosis, NBT reduction, actin polymerization, chemotaxis and adhesion molecule expression. Undifferentiated HL60 cells could not polymerize actin or reduce NBT, and exhibited only a minimal ability to undergo chemotaxis or ingest latex beads. Following 4 days of maturation with ATRA, the cells would increase F-actin content in response to interleukin-8, ingest latex beads, migrate in a chemotaxis chamber, reduce NBT, and express CD11b. When dexamethasone was added to the cells in culture, there was no major enhancement or suppression of these properties. We also studied the effect of dexamethasone on functional properties of normal neutrophils and found minimal if any effect on their function. Overall, these studies suggest that in vitro, dexamethasone has little effect on the function of leukemic and normal granulocytes. To further investigate the pathophysiology of the retinoic acid syndrome, future studies may need to use endothelial cells, cytokines, or granulocytes obtained from APL patients.