Pei-Chin Lin

Improved efficacy and tolerability of oral deferasirox by twice-daily dosing for patients with transfusion-dependent β-thalassemia†

Deferasirox is an oral iron‐chelating agent taken once‐daily by patients with transfusion‐dependent iron overload. However, some patients are unresponsive or unable to tolerate once‐daily deferasirox. The current study evaluated whether twice‐daily deferasirox treatment showed increased efficacy or tolerability in unresponsive or intolerant patients.

Effects of sildenafil on pulmonary hypertension and levels of ET-1, eNOS, and cGMP in aorta-banded rats.

Sildenafil, an oral phosphodiesterase Type 5 inhibitor, has vasodilatory effects through a cGMP-dependent mechanism. We previously showed that aortic banding could result in left ventricular overloading and pulmonary hypertension (PH). In this study, we investigated whether early administration of sildenafil, either immediately after or 2 weeks after aortic banding, could ameliorate the development of PH and alter gene expression of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS), and alter the levels of cGMP in rats undergoing an ascending aortic banding. Rats (n = 32) were divided into sham-operated and banding groups with or without treatment. The banded rats were further divided into three groups: (i) receiving saline on Days 1–28 (AOB28; n = 8), (ii) receiving saline on Days 1–14 followed by treatment with 50 mg/kg/day sildenafil on Days 15–28 (AOB28/Sil15–28; n = 8), and (iii) receiving 50 mg/kg/day sildenafil on days 1–28 (AOB28/Sil1–28; n = 8). The sham-operated rats were administrated saline on Days 1–28 (n = 8). Four weeks after banding, there was a significant development of PH with pulmonary vascular remodeling. Although both sildenafil-treatment groups had significant increases in cGMP and had reductions in the thickening in the medial layer of pulmonary arteriole, notable attenuation of PH occurred only in the AOB28/Sil1–28 group. PreproET-1 and eNOS messenger RNA (mRNA) expressions were measured by competitive reverse transcription polymerase chain reaction, and eNOS protein was determined by Western blotting. Sildenafil did not alter the elevated ET-1 or preproET-1 mRNA in banded rats. Interestingly, pulmonary eNOS increased in the AOB28/Sil1–28 group. In conclusion, early treatment with sildenafil inhibited the rise in pulmonary arterial pressure and pulmonary vascular remodeling in PH secondary to heart failure, and cGMP, but not ET-1, might be involved. Clinically, early repeated administration of sildenafil may offer an alternative in protecting against PH in heart failure.

Isocitrate dehydrogenase mutation hot spots in acute lymphoblastic leukemia and oral cancer

Isocitrate dehydrogenase (IDH) encodes a nicotinamide adenine dinucleotide phosphate+‐dependent enzyme for oxidative decarboxylation of isocitrate and has an essential role in the tricarboxylic acid cycle. Mutations of IDH1 and IDH2 have been identified in patients with glioma, leukemia, and other cancers. However, the incidence of IDH mutations in acute myeloid leukemia in Taiwan is much lower than that reported in Western countries. The reason for the difference is unknown and its clinical implications remain unclear. Acute lymphoblastic leukemia (ALL) is a heterogenous hematopoietic malignancy. Oral squamous cell carcinoma (OSCC) results from chronic carcinogen exposures and is highly prevalent in trucking workers, especially in southern Taiwan. Subtypes of both diseases require specific treatments, and molecular markers for developing tailored treatments are limited. High‐resolution melting (HRM) analysis is now a widely used methodology for rapid, accurate, and low‐cost mutation scanning. In this study, 90 adults with OSC and 31 children with ALL were scanned by HRM analysis for IDH1 and IDH2 mutation hot spots. In ALL, the allele frequency was 3.23% in both IDH1 and IDH2. In OSCC, the allele frequency was 2.22% in IDH2. A synonymous mutation over pG313 (c.939A > G) of IDH2 was found in both pediatric ALL and adult OSCC. Therefore, we concluded that mutations of IDH are uncommon in ALL and OSCC and are apparently not a major consideration when selecting treatment modalities.

Long noncoding RNA MIAT promotes non-small cell lung cancer proliferation and metastasis through MMP9 activation

Long noncoding RNAs (lncRNAs) play crucial roles in carcinogenesis. Myocardial infarction-associated transcript (MIAT), originally isolated as a candidate gene for myocardial infarction, has been found to act as an oncogene in chronic lymphocytic leukaemias and neuroendocrine prostate cancer (NEPC); however, little is known about its expression pattern, biological function, and underlying mechanism in non-small cell lung cancer (NSCLC). In this study, we observed that MIAT expression was upregulated in NSCLC, and its overexpression was associated with advanced tumor stage. Moreover, MIAT knockdown decreased cell proliferation, migration, invasion, and cell cycle arrested in G1 phase. Mechanistic investigation revealed that MIAT could interact with histone methyltransferase mixed-lineage leukemia (MLL). MIAT silencing impeded the binding of MLL on the matrix metalloproteinase 9 (MMP9) promoter region and epigenetically reduced MMP9 transcriptional activity. Overall, our findings suggest that MIAT expression is associated with NSCLC and may be one of the critical targets in progression and metastasis in NSCLC.

Rapid identification of CYP2C8 polymorphisms by high resolution melting analysis

BACKGROUND Cytochrome P450 (CYP) 2C8 is the principal enzyme responsible for the metabolism of arachidonic acid and various drugs, and influences drug-drug interactions and some associated diseases. Large interindividual differences in CYP2C8 enzymatic activity and several nonsynonymous genetic variations have been reported in different races. Therefore, how to identify CYP2C8 polymorphisms efficiently for genotyping in different populations is very important. METHODS A high resolution melting (HRM) analysis was used to characterize the CYP2C8 polymorphism. Genomic DNA was extracted from peripheral blood samples from 95 normal individuals in Taiwan. Nine exons of the CYP2C8 gene were screened by HRM analysis. All results were confirmed by direct DNA sequencing. RESULTS Five new single nucleotide polymorphisms (SNPs) were found in this study; two SNPs [1189G>A (D397N) and 1230C>T (G410G)] were in exon 8 and the others [1312G>C (E438Q), 1497T>C (A499A) and 1677delT (559delL)] were in exon 9. The 1497T>C (A499A) was the most common variant with an allele frequency of 20.53% but without amino acid substitution. CONCLUSIONS HRM analysis is a fast, reliable, accurate and cost-effective screening method for gene mutations, even very similar cDNA sequences with 83% identities, compared with CYP2C8 and CYP2C9.

Immune tolerance induction therapy for patients with hemophilia A and FVIII inhibitors particularly using low-dose regimens†

Inhibitory antibodies against infused clotting factor VIII concentrates (FVIII) developed in 20–30% of patients with hemophilia A. Bypass therapy may control the bleeds in patients with FVIII inhibitors, however, immune tolerance induction (ITI) therapy is the only proven modality for eradicating FVIII inhibitors. Since the cost of high‐dose (200 IU/kg) ITI is extremely expansive, we conducted this study to identify whether low‐dose ITI can be an alternative strategy besides high‐dose ITI or bypass therapy.

Wntless (GPR177) expression correlates with poor prognosis in B-cell precursor acute lymphoblastic leukemia via Wnt signaling

B-cell precursor acute lymphoblastic leukemia (BCP ALL) is the most common childhood leukemia, with a cure rate of 80%. Nevertheless, disease relapse is the most important prognostic factor for the disease outcome. We aimed to elucidate the role of Wnt secretion-regulating protein, Wntless (Wls)/GPR177, on disease outcome in pediatric patients with BCP ALL, and assess its pathogenetic role in the regulation of the disease. Wls expression was characterized and correlated with Wnt pathway signaling in the bone marrow leukemia cells isolated from 44 pediatric patients with BCP ALL. The overexpression of Wls was detected in leukemia cells and was significantly correlated with the disease relapse and poor survival in the patients. The high expression of Wls also correlated with the Wnt expression and consequent downstream signaling activation, which was shown to provide essential proliferation, transformation and anti-apoptotic activity during leukemogenesis. These results indicated that Wls played an essential role in disease relapse and poor survival in patients with BCP ALL. Therefore, Wls may provide a potential future therapeutic target, particularly for patients who do not respond to existing therapies and suffer relapse.

Ganglioneuroma of Posterior Mediastinum in a 6-year-old Girl: Imaging for Pediatric Intrathoracic Incidentaloma

Intrathoracic tumor is a rare entity in the pediatric population and neurogenic tumors account for 40‐50% of childhood intrathoracic tumors. They can cause severe symptoms, such as respiratory distress, neurological dysfunction and metabolic disturbances. Posterior mediastinal ganglioneuroma (GN) usually occurs in children and can be found accidentally. Precise preoperative diagnosis is very difficult and has a great influence on surgical intervention. Here, we report a 6‐year‐old girl with a posterior mediastinal GN that was found incidentally on chest radiography. Computed tomography and magnetic resonance imaging demonstrated a right paraspinal tumor with punctuate calcification and intraspinal extension. 18F‐fluorodeoxyglucose positron emission tomography revealed low‐grade fluorodeoxyglucose avidity of this tumor. Computed tomography and magnetic resonance imaging can characterize GN and positron emission tomography is helpful for differentiating benign or malignant lesions.

Efficient detection of factor IX mutations by denaturing high-performance liquid chromatography in Taiwanese hemophilia B patients, and the identification of two novel mutations

Hemophilia B (HB) is an X‐linked recessive disorder characterized by mutations in the clotting factor IX (FIX) gene that result in FIX deficiency. Previous studies have shown a wide variation of FIX gene mutations in HB. Although the quality of life in HB has greatly improved mainly because of prophylactic replacement therapy with FIX concentrates, there exists a significant burden on affected families and the medical care system. Accurate detection of FIX gene mutations is critical for genetic counseling and disease prevention in HB. In this study, we used denaturing high‐performance liquid chromatography (DHPLC), which has proved to be a highly informative and practical means of detecting mutations, for the molecular diagnosis of our patients with HB. Ten Taiwanese families affected by HB were enrolled. We used the DHPLC technique followed by direct sequencing of suspected segments to detect FIX gene mutations. In all, 11 FIX gene mutations (8 point mutations, 2 small deletions/insertions, and 1 large deletion), including two novel mutations (exon6 c.687–695, del 9 mer and c.460–461, ins T) were found. According to the HB pedigrees, 25% and 75% of our patients were defined as familial and sporadic HB cases, respectively. We show that DHPLC is a highly sensitive and cost‐effective method for FIX gene analysis and can be used as a convenient system for disease prevention.

TEL/AML1 fusion gene in childhood acute lymphoblastic leukemia in southern Taiwan.

Chromosomal abnormalities are found in 80–90% of childhood cases of acute lymphoblastic leukemia (ALL). Leukemia‐specific chromosome aberrations not only have prognostic value, but also provide important clues for further investigation into leukogenesis, leukemic cell transformation, and proliferation. This study used reverse transcriptase–polymerase chain reaction techniques to detect transcripts of the leukemia‐specific chromosome fusion gene, TEL/AML1, and to monitor the expression levels of the TEL‐AML1 fusion transcript in ALL patients at sequential intervals during their treatment course. Twenty‐five ALL patients were enrolled, including 20 who were newly diagnosed and five in relapse. The incidence of the TEL/AML1 fusion gene in this study was 32%. The clinical features of our eight TEL/AML1‐positive ALL cases were similar to those in other studies. Blotting analysis of the levels of the TEL‐AML1 fusion transcript was used to detect minimal residual disease. Reduced levels of TEL/AML1 expression were found in four of the six patients whose bone marrow or peripheral blood samples were obtained after treatment. Further investigation with a larger sample size is warranted.