Oncogenic effects of evolutionarily conserved noncoding RNA ECONEXIN on gliomagenesis.

Accumulating studies have demonstrated the importance of long noncoding RNAs (lncRNAs) during oncogenic transformation. However, because most lncRNAs are currently uncharacterized, the identification of novel oncogenic lncRNAs is difficult. Given that intergenic lncRNA have substantially less sequence conservation patterns than protein-coding genes across species, evolutionary conserved intergenic lncRNAs are likely to be functional. The current study identified a novel intergenic lncRNA, LINC00461 (ECONEXIN) using a combined approach consisting of searching lncRNAs by evolutionary conservation and validating their expression in a glioma mouse model. ECONEXIN was the most highly conserved intergenic lncRNA containing 83.0% homology with the mouse ortholog (C130071C03Rik) for a region over 2500 bp in length within its exon 3. Expressions of ECONEXIN and C130071C03Rik were significantly upregulated in both human and mouse glioma tissues. Moreover, the expression of C130071C03Rik was upregulated even in precancerous conditions and markedly increased during glioma progression. Functional analysis of ECONEXIN in glioma cell lines, U87 and U251, showed it was dominantly located in the cytoplasm and interacted with miR-411-5p via two binding sites within ECONEXIN. Inhibition of ECONEXIN upregulated miR-411-5p together with the downregulation of its target, Topoisomerase 2 alpha (TOP2A), in glioma cell lines, resulting in decreased cell proliferation. Our data demonstrated that ECONEXIN is a potential oncogene that regulates TOP2A by sponging miR-411-5p in glioma. In addition, our investigative approaches to identify conserved lncRNA and their molecular characterization by validation in mouse tumor models may be useful to functionally annotate novel lncRNAs, especially cancer-associated lncRNAs.

miR-615-5p is epigenetically inactivated and functions as a tumor suppressor in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly invasive cancer with a poor prognosis. Although microRNA (miRNA) transcripts have a crucial role in carcinogenesis and development, little information is known regarding the aberrant DNA methylation of miRNAs in PDAC. Using methylated DNA immunoprecipitation-chip analysis, we found that miR-615-5p was hypermethylated in its putative promoter region, which silenced its expression in PDAC cell lines. In addition, the overexpression of miR-615-5p in pancreatic cancer cells suppressed cell proliferation, migration and invasion. Insulin-like growth factor 2 (IGF2) is an imprinted gene, and its abnormal expression contributes to tumor growth. Here, we identified IGF2 as a target of miR-615-5p using a luciferase reporter assay. IGF2 upregulation in PDAC tissues was not correlated with a loss of imprinting but was inversely correlated with miR-615-5p downregulation. In addition, miR-615-5p suppressed pancreatic cancer cell proliferation, migration and invasion by directly targeting IGF2, and this effect could be reversed by co-transfection with IGF2. Furthermore, the stable overexpression of miR-615-5p inhibited tumor growth in vivo and was correlated with IGF2 expression. Using RNA sequencing, we further identified miR-615-5p as potentially targeting other genes, such as the proto-oncogene JUNB, and interfering with the insulin signaling pathway. Taken together, our results demonstrate that miR-615-5p was abnormally downregulated in PDAC cells due to promoter hypermethylation, which limited its inhibition of IGF2 and other target genes, thereby contributing to tumor growth, invasion and migration. These data demonstrate a novel and important role of miR-615-5p as a tumor suppressor in PDAC.

High expression of N-acetylglucosaminyltransferase IVa promotes invasion of choriocarcinoma.

BACKGROUND: Gestational trophoblastic diseases (GTDs) are related to trophoblasts, and human chorionic gonadotropin (hCG) is secreted by GTDs as well as normal placentas. However, the asparagine-linked sugar chains on hCG contain abnormal biantennary structures in invasive mole and choriocarcinoma, but not normal pregnancy or hydatidiform mole. N-acetylglucosaminyltransferase-IV (GnT-IV) catalyses ß1,4-N-acetylglucosamine branching on asparagine-linked oligosaccharides, which are consistent with the abnormal sugar chain structures on hCG. METHODS: We investigated GnT-IVa expression in GTDs and placentas by immunohistochemistry, western blot, and RT-PCR. We assessed the effects of GnT-IVa knockdown in choriocarcinoma cells in vitro and in vivo. RESULTS: The GnT-IVa was highly expressed in trophoblasts of invasive mole and choriocarcinoma, and moderately in extravillous trophoblasts during the first trimester, but not in hydatidiform mole or other normal trophoblasts. The GnT-IVa knockdown in choriocarcinoma cells significantly reduced migration and invasive capacities, and suppressed cellular adhesion to extracellular matrix proteins. The extent of ß1,4-N-acetylglucosamine branching on ß1 integrin was greatly reduced by GnT-IVa knockdown, although the expression of ß1 integrin was not changed. In vivo studies further demonstrated that GnT-IVa knockdown suppressed tumour engraftment and growth. CONCLUSION: These findings suggest that GnT-IVa is involved in regulating invasion of choriocarcinoma through modifications of the oligosaccharide chains of ß1 integrin.

CMC-544 (inotuzumab ozogamicin), an anti-CD22 immuno-conjugate of calicheamicin, alters the levels of target molecules of malignant B-cells.

We studied the effect of CMC-544, the calicheamicin-conjugated anti-CD22 monoclonal antibody, used alone and in combination with rituximab, analyzing the quantitative alteration of target molecules, that is, CD20, CD22, CD55 and CD59, in Daudi and Raji cells as well as in cells obtained from patients with B-cell malignancies (BCM). Antibody inducing direct antiproliferative and apoptotic effect, complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) were tested separately. In Daudi and Raji cells, the CDC effect of rituximab significantly increased within 12 h following incubation with CMC-544. The levels of CD22 and CD55 were significantly reduced (P<0.001 in both cells) after incubation with CMC-544, but CD20 level remained constant or increased for 12 h. Similar results were obtained in cells from 12 patients with BCM. The antiproliferative and apoptotic effect of CMC-544 were greater than that of rituximab. The ADCC of rituximab was not enhanced by CMC-544. Thus, the combination of CMC-544 and rituximab increased the in vitro cytotoxic effect in BCM cells, and sequential administration for 12 h proceeded by CMC-544 was more effective. The reduction of CD55 and the preservation of CD20 after incubation with CMC-544 support the rationale for the combined use of CMC-544 and rituximab.

Efficacy of gemtuzumab ozogamicin on ATRA- and arsenic-resistant acute promyelocytic leukemia (APL) cells.

Acute promyelocytic leukemia (APL) cells express a considerable level of CD33, which is a target of gemtuzumab ozogamicin (GO), and a significantly lower level of P-glycoprotein (P-gp). In this study, we examined whether GO was effective on all-trans retinoic acid (ATRA)- or arsenic trioxide (ATO)-resistant APL cells. Cells used were an APL cell line in which P-gp was undetectable (NB4), ATRA-resistant NB4 (NB4/RA), NB4 and NB4/RA that had been transfected with MDR-1 cDNA (NB4/MDR and NB4/RA/MDR, respectively), ATO-resistant NB4 (NB4/As) and blast cells from eight patients with clinically ATRA-resistant APL including two patients with ATRA- and ATO-resistant APL. The efficacy of GO was analyzed by (3)H-thymidine incorporation, the dye exclusion test and cell cycle distribution. GO suppressed the growth of NB4, NB4/RA and NB4/As cells in a dose-dependent manner. GO increased the percentage of hypodiploid cells significantly in NB4, NB4/RA and NB4/As cells, and by a limited degree in NB4/MDR and NB4/RA/MDR cells. Similar results were obtained using blast cells from the patients with APL. GO is effective against ATRA- or ATO-resistant APL cells that do not express P-gp, and the mechanism of resistance to GO is not related to the mechanism of resistance to ATRA or ATO in APL cells. Leukemia (2005) 19, 1306-1311. doi:10.1038/sj.leu.2403807; published online 26 May 2005.

Reduced effect of gemtuzumab ozogamicin (CMA-676) on P-glycoprotein and/or CD34-positive leukemia cells and its restoration by multidrug resistance modifiers.

Gemtuzumab ozogamicin (CMA-676), a calicheamicin-conjugated humanized anti-CD33 mouse monoclonal antibody, has recently been introduced clinically as a promising drug for the treatment of patients with acute myeloid leukemia (AML), more than 90% of which express CD33 antigen. However, our recent study suggested that CMA-676 was excreted by a multi- drug-resistance (MDR) mechanism in P-glycoprotein (P-gp)-expressing leukemia cell lines. We analyzed the in vitro effects of CMA-676 on leukemia cells from 27 AML patients in relation to the amount of P-gp, MDR-associated protein 1 (MRP1), CD33 and CD34, using a multi-laser-equipped flow cytometer. The cytocidal effect of CMA-676, estimated by the amount of hypodiploid portion on cell cycle, was inversely related to the amount of P-gp estimated by MRK16 monoclonal antibody (P = 0.004), and to the P-gp function assessed by intracellular rhodamine-123 accumulation in the presence of PSC833 or MS209 as a MDR modifier (P = 0.0004 and P = 0.002, respectively). In addition, these MDR modifiers reversed CMA-676 resistance in P-gp-expressing CD33(+) leukemia cells (P = 0.001 with PSC833 and P = 0.0007 with MS209). In CD33(+) AML cells from 13 patients, CMA-676 was less effective on CD33(+)CD34(+) than CD33(+)CD34(-) cells (P = 0.002). PSC833 partially restored the effect of CMA-676 in CD33(+)CD34(+) cells. These results suggest that the combined use of CMA-676 and a MDR modifier will be more effective on CD33(+) AML with P-gp-related MDR.

Arsenic trioxide therapy for relapsed or refractory Japanese patients with acute promyelocytic leukemia: need for careful electrocardiogram monitoring.

Recent studies have shown that arsenic trioxide (As(2)O(3)) can induce complete remission in patients with acute promyelocytic leukemia (APL). We tested the efficacy and safety of As(2)O(3) for the treatment of patients with APL who had relapsed from or become refractory to all-trans retinoic acid (ATRA) and conventional chemotherapy in a prospective study. As(2)O(3) at a dose of 0.15 mg/kg was administered until the date of bone marrow remission to a maximum of 60 days. In patients who achieved complete remission (CR), one additional course of As(2)O(3) was administered using the same dose for 25 days. Of 14 patients, 11 (78%) achieved CR. Six of 10 patients who achieved CR showed disappearance of PML-RARalpha transcript by RT-PCR assay. The duration of As(2)O(3)-induced CR ranged from 4 to 22 months (median, 8 months) at a median follow-up of 17 months. Adverse events included 13 electrocardiogram abnormalities (13 QTc prolongation, eight ventricular premature contraction, four nonsustained ventricular tachycardia and two paroxysmal supraventricular tachycardia), seven nausea and vomiting, four pruritus, three peripheral neuropathy, three fluid retention and one APL differentiation syndrome. Four patients received antiarrhythmic agents. Hyperleukocytosis developed in five patients and in three cytotoxic drugs were necessary. Other adverse events were relatively mild. As(2)O(3) treatment is effective and relatively safe in relapsed or refectory patients with APL. Cardiac toxicities in patients with QTc prolongation should be carefully monitored.

All-trans retinoic acid (ATRA) differentiates acute promyelocytic leukemia cells independently of P-glycoprotein (P-gp) related multidrug resistance.

Here the relationship between all-trans retinoic acid (ATRA)-resistance and P-glycoprotein (P-gp)-associated multidrug resistance (MDR) is discussed in acute promyelocytic leukemia (APL). First, the remission rates of ATRA therapy are similar in relapsed/refractory APL to the preceding chemotherapy given and in newly diagnosed APL. Second, MDR1 cDNA-transduced NB4 (NB4/MDR) cells accumulate less Rhodamine-123 (Rh123) than NB4 cells, but there is no difference in the intracellular ATRA concentration between them. PSC833 or MS209. MDR modifiers, increases the intracellular accumulation of Rh123 in NB4/MDR and APL cells expressing P-gp, but not of ATRA. Third, the expression of CD11b, the NBT reduction activity, the proportion of apoptotic cells and the morphology are not different between NB4/MDR and NB4 cells, and between APL cells expressing P-gp and not. APL cells express little P-gp, and mainly express CD33 but no CD34. Despite previous reports that ATRA-resistant APL cells express more P-gp than ATRA-sensitive ones, P-gp and ATRA-resistance seems to exist independently.

[Pulmonary alveolar proteinosis successfully treated by a modified lavage technique using high-frequency jet ventilation].

A 66-year-old woman presented with exertional dyspnea and productive cough. Chest radiography showed ground glass opacities and patchy infiltrates in both lungs. After confirmation of pulmonary alveolar proteinosis by bronchoalveolar lavage, she underwent conventional whole-lung lavage with slight improvement, with the aid of a partial extracorporeal circulation. After aggravation for one year, a modified lavage technique using high-frequency jet ventilation was used, and persistent improvement in oxygenation was achieved. We believe that this modified technique could be a useful method for pulmonary alveolar proteinosis.

[A patient with lymphoma of mucosa-associated lymphoid tissue (MALT) and adenocarcinoma in the same tumor of the lung].

A 60-year-old woman with no symptoms was found to have a mass shadow in the left lower lobe of the lung on chest radiography. Open lung biopsy and left lower lobectomy were performed. Histopathological study of the specimen revealed two distinct neoplasms. One tumor was a low grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) of the lung, while the other was an adenocarcinoma. The two neoplasms were admixed to form a composite tumor.

[Successful treatment using iron depletion phlebotomy combined with recombinant erythropoietin after allogeneic bone marrow transplantation for myelodysplastic syndrome complicated by secondary hemochromatosis].

A 33 year-old female patient presented with apparent skin pigmentation, sustained liver dysfunction and impaired glucose tolerance. She had received blood transfusions totalling more than 40,000 ml for myelodysplastic syndrome and an allogeneic bone marrow transplant from her HLA-matched sister at the age of 31. Ferrokinetic data showed a significant iron overload. Magnetic resonance imaging suggested excessive iron deposition in the liver. The patient was diagnosed as having secondary hemochromatosis. She was given subcutaneous injections of 6,000 units of recombinant human erythropoietin initially twice a week and then weekly, and phlebotomies were performed to maintain her hemoglobin level above 10 g/dl. Three years later, the total volume of phlebotomized blood reached 24,000 ml, and her ferrokinetic data, serum transaminase levels, glucose tolerance and skin color were significantly improved.

Decreased amount of mpl and reduced expression of glycoprotein IIb/IIIa and glycoprotein Ib on platelets from patients with refractory anemia: analysis by a non-isotopic quantitative ligand binding assay and immunofluorescence.

Using a non-isotopic ligand binding assay and immunofluorescence, we examined the amount of mpl, glycoprotein IIb/IIIa (gpIIb/IIIa) and glycoprotein Ib (gpIb) on platelets from healthy volunteers and patients with refractory anemia (RA). For the analysis of mpl expression, we applied both a non-isotopic ligand binding assay and immunofluorescence using anti-mpl monoclonal antibody, and compared the results from both methods. The non-isotopic ligand binding assay has been developed in our laboratory and is suitable for the quantitative analysis of a small amount of cytokine receptors such as mpl on platelets. In platelets from patients with RA, the amount of mpl expressed by the D value was 0.05+/-0.03 (mean+/-standard deviation), and was significantly lower than that in healthy volunteers (0.15+/-0.05, p<0.0001). The mean fluorescence intensities (MFI) of gpIIb/IIIa and gpIb on platelets from RA patients were 28.8+/-8.8 and 20.8+/-7.7, respectively, and were significantly lower than those on normal subjects (93.2+/-22.6 and 67.4+/-9.1, p<0.0001 and p<0.0001, respectively). There was a good correlation between the amount of mpl and the MFI of gpIIb/IIIa (p=0.794, p<0.0001) or gpIb (p=0.774, p<0.0001), and between those of gpIIb/IIIa and gpIb (p=0.728, p<0.0001). We demonstrated a decreased amount of mpl as well as a reduced expression of gpIIb/IIIa and gpIb on platelets from RA patients.

[Bronchiolitis obliterans organizing pneumonia after adjuvant thoracic radiotherapy for breast cancer: a case report].

We report a case of recurrent cough and migratory pulmonary infiltrates in a 55-year-old woman after adjuvant thoracic radiotherapy for breast cancer. The pulmonary infiltrates were initially limited to the area adjacent to the irradiated breast, but later migrated to the opposite lung. The diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP) was made using a transbronchial biopsy, which disclosed intraluminal fibrosis in the distal airspace, together with a radiographic appearance typical of BOOP. This case was assumed to be in a series of reported cases of BOOP primed by radiotherapy.

The prostaglandin E2 EP1 receptor mediates pain perception and regulates blood pressure.

The lipid mediator prostaglandin E2 (PGE2) has diverse biological activity in a variety of tissues. Four different receptor subtypes (EP1-4) mediate these wide-ranging effects. The EP-receptor subtypes differ in tissue distribution, ligand-binding affinity, and coupling to intracellular signaling pathways. To identify the physiological roles for one of these receptors, the EP1 receptor, we generated EP1-deficient (EP1-/-) mice using homologous recombination in embryonic stem cells derived from the DBA/1lacJ strain of mice. The EP1-/- mice are healthy and fertile, without any overt physical defects. However, their pain-sensitivity responses, tested in two acute prostaglandin-dependent models, were reduced by approximately 50%. This reduction in the perception of pain was virtually identical to that achieved through pharmacological inhibition of prostaglandin synthesis in wild-type mice using a cyclooxygenase inhibitor. In addition, systolic blood pressure is significantly reduced in EP1 receptor-deficient mice and accompanied by increased renin-angiotensin activity, especially in males, suggesting a role for this receptor in cardiovascular homeostasis. Thus, the EP1 receptor for PGE2 plays a direct role in mediating algesia and in regulation of blood pressure.

Prolongation of the QT interval and ventricular tachycardia in patients treated with arsenic trioxide for acute promyelocytic leukemia.

BACKGROUND: Recently, arsenic trioxide has increasingly been used for relapsed acute promyelocytic leukemia. However, it is known to have several adverse effects, including acute cardiac toxicities. OBJECTIVE: To determine cardiac toxicities resulting from arsenic trioxide therapy in patients with relapsed or refractory acute promyelocytic leukemia. DESIGN: Phase II clinical prospective cohort study. SETTING: A university hospital in Hamamatsu, Japan. PATIENTS: 8 patients with relapsed acute promyelocytic leukemia. INTERVENTION: Arsenic trioxide, 0.15 mg/kg of body weight, administered daily by 2-hour infusion for a maximum of 60 days. MEASUREMENTS: Continuous monitoring with ambulatory electrocardiography. RESULTS: Five patients (63%) achieved complete remission. During induction therapy with arsenic trioxide, prolonged QT intervals were observed in all patients. Ventricular premature contractions were noticed during 8 of 12 courses of therapy. Four patients developed nonsustained ventricular tachycardia and required treatment with antiarrhythmic agents. CONCLUSIONS: Cardiac toxicity occurs during arsenic trioxide therapy in patients with acute promyelocytic leukemia. Such patients should be monitored for prolonged QT intervals and ventricular arrhythmia.

Retrovirus-mediated gene transfer of granulocyte colony-stimulating factor receptor (G-CSFR) cDNA into MDS cells and induction of their differentiation by G-CSF.

Myelodysplastic syndromes (MDS) are clonal disorders in which the proper differentiation of hematopoietic stem cells is impaired. There is no effective treatment for this stem cell disorder at present. In an attempt to find a new strategy that promotes the differentiation of MDS blast cells, we tried retroviral transduction of granulocyte colony-stimulating factor receptor (G-CSFR) into an interleukin-3-dependent MDS cell line, MDS-L, since expression of G-CSFR is known to be essential for the differentiation of myeloid progenitor cells and this expression is impaired in most MDS cells. Ectopic expression of human G-CSFR cDNA in MDS-L cells gave rise to granulocytic differentiation by G-CSF stimulation. G-CSF caused the transformants expressing G-CSFR to display a morphological characteristic of mature granulocytes, upregulated CD11b on the cell surface, and improved NBT reduction activity. These results demonstrate that MDS-L cells ecopically expressing G-CSFR are induced to granulocytic differentiation upon exposure to G-CSF, and shed light on the molecular mechanisms of maturation arrest in MDS cells.

In vitro IL-12 treatment of peripheral blood mononuclear cells from patients with leukemia or myelodysplastic syndromes: increase in cytotoxicity and reduction in WT1 gene expression.

Interleukin-12 (IL-12) has potent antitumor activities. We examined whether IL-12 enhanced the cytotoxicity of peripheral blood mononuclear cells (PBMNC) and decreased leukemia cells in 30 patients with leukemia or myelodysplastic syndromes (MDS): 12 acute myeloid leukemia (AML) (five in complete remission (CR) and seven in non-CR); six chronic myeloid leukemia (CML); and 12 MDS (three refractory anemia (RA), eight RA with excess of blasts and one chronic myelomonocytic leukemia). PBMNC from patients and five healthy volunteers were cultured at 5 x 10(5)/ml parallel with or without 100 units/ml of IL-12 for 3 days. Cytotoxicity of PBMNC against K562 cells was assessed by flow cytometry. To quantify the amount of leukemia cells, WT1 mRNA was measured by competitive reverse transcription polymerase chain reaction (RT-PCR), since WT1 mRNA is considered as a marker of minimal residual disease (MRD) in leukemia or MDS. The cytotoxicity of non-IL-12-treated PBMNC of 30 patients was 13.4+/-9.3% at the effector to target (E:T) ratio of 20:1, and significantly lower than that of normal subjects (25.7+/-8.4%). The cytotoxicity increased to 30.6+/-17.9% in the IL-12-treated PBMNC. WT1 mRNA in PBMNC of five healthy volunteers was less than 10(3) copies/microg of total RNA. Following the 3-day IL-12 treatment, mean WT1 mRNA of PBMNC was reduced from 10(4.8) to 10(4.2) copies/microg of total RNA in six CML patients, from 10(5.4) to 10(4.8) copies/microg in 12 MDS patients and from 10(5.0) to 10(4.2) copies/microg in five AML patients in CR, but not reduced in five of seven AML in non-CR. These results showed that IL-12 significantly enhanced PBMNC cytotoxicity and decreased the quantity of leukemia cells in PBMNC of most patients with MDS, CML and AML in CR. IL-12 might be of considerable benefit in the elimination of MRD in patients with hematological malignancies.

Calicheamicin-conjugated humanized anti-CD33 monoclonal antibody (gemtuzumab zogamicin, CMA-676) shows cytocidal effect on CD33-positive leukemia cell lines, but is inactive on P-glycoprotein-expressing sublines.

Calicheamicin-conjugated humanized anti-CD33 mouse monoclonal antibody, CMA-676, has recently been introduced to clinics as a promising drug to treat patients with acute myeloid leukemia (AML) in relapse. However, the mechanism of action of CMA-676 has not been well elucidated. The cytotoxic effect of CMA-676 on HL60, NOMO-1, NB4, NKM-1, K562, Daudi, and the multidrug-resistant sublines, NOMO-1/ADR and NB4/MDR, was investigated by cell cycle distribution and morphology. These studies were done by a video-microscopic system, DNA fragmentation, dye exclusion and 3H-thymidine uptake after analysis of CD33, CD34, P-glycoprotein (P-gp), multidrug resistance (MDR)-associated protein and lung-related protein on these cells. A dose-dependent, selective cytotoxic effect of CMA-676 was observed in cell lines that expressed CD33, and was dependent on the amount of CD33 and the proliferative speed of the cells. Sensitive cells were temporally arrested at the G2/M phase before undergoing morphological changes. CMA-676 is not effective on P-gp-expressing multidrug-resistant sublines compared with parental cell lines. MDR modifiers, MS209 and PSC833, restored the cytotoxic effect of CMA-676 in P-gp-expressing sublines. CMA-676 is a promising agent in the treatment of patients with AML that expresses CD33. The combined use of CMA-676 and MDR modifiers may increase the selective cytotoxic effect in multidrug-resistant AML.