Yoon Hwan Chang

High prevalence of hepatitis B virus infection in patients with B-cell non-Hodgkin's lymphoma in Korea.

This study assessed the association of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection with non‐Hodgkins lymphoma in a highly HBV‐endemic area. The prevalence of either HBV or HCV infection in 235 patients with non‐Hodgkins lymphoma was compared with that of an age‐ and sex‐matched hospital control group of 235 patients. The prevalence of HBV infection was higher in B‐cell non‐Hodgkins lymphoma (15.5%) than control (8.1%), but the prevalence of HCV infection in the non‐Hodgkins lymphoma patients (2.1%) and control group (3%) was similar. HBV prevalence increased significantly with age in the B‐cell non‐Hodgkins lymphoma patients. The presence of HBV proteins and DNA in lymphoma tissues and peripheral blood mononuclear cells (PBMCs) from HBV‐infected non‐Hodgkins lymphoma patients was also investigated using immunohistochemistry and PCR. HBV DNA was frequently detected in PBMCs from HBV‐infected non‐Hodgkins lymphoma patients, but HBV antigens were not. Therefore, HBV infection, but not HCV infection, was associated with B‐cell non‐Hodgkins lymphoma in Korea, suggesting a possible role for HBV in the development of non‐Hodgkins lymphoma. J. Med. Virol. 80:960–966, 2008.

Multiple myeloma in Korea: past, present, and future perspectives. Experience of the Korean Multiple Myeloma Working Party.

The incidence of multiple myeloma suggests an ethnic difference. Compared to Caucasians, who have an incidence rate of 3–5/100,000, Asians show much lower incidence rate compared to them, in the range of 0.5–3/100,000. In Korea, The very first case report of multiple myeloma was published in 1959 [1], and was followed by a few case reports until the 1970s. Since that time, the number of cases of multiple myeloma in Korea increased steadily, reaching 100 cases/year in 1990 [2] and 500 cases/year in 2000 [3], and it is still going up. Currently in Korea, 1,000 patients are estimated to be diagnosed with multiple myeloma, and 700 patients are assumed to die of this disease every year, and 4,000–5,000 patients are suffering from this disease [4]. The most updated, age-standardized, incidence rate of multiple myeloma in Korea is 1.4/100,000, and ranked as the third most common among the hematologic malignancies, only surpassed by non-Hodgkin’s lymphoma and acute myeloid leukemia [5]. Besides, the mortality from multiple myeloma

Secondary hematological malignancies after breast cancer chemotherapy

According to several reports, the 10 year incidence of secondary acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) after systemic chemotherapy is approximately 1.5%. The cumulative risk increases by 0.25--1% for the first 8 years after treatment. We have reported only 6 cases of hematological malignancies (0.3%) after breast cancer chemotherapy in our institute. We detected 2 cases of secondary AML and 1 case of MDS, 19, 52 and 12 months, respectively, after systemic chemotherapy for breast cancer. Published data on the occurrence of secondary hematological malignancies other than AML or MDS in this setting are scarce. We encountered diffuse large B-cell lymphoma, angioimmunoblastic lymphoma and mantle cell lymphoma as secondary hematological malignancies after systemic chemotherapy for breast cancer.

A Case of Uterine Cervical Cancer Presenting with Granulocytosis

Granulocytosis occurs in 40% of patients with lung and gastrointestinal cancers, 20% of patients with breast cancer, 30% of patients with brain tumor and ovarian cancer and 10% of patients with renal cell carcinoma. Granulocytosis occurs because of production of G-CSF, GM-CSF and IL-6. Uterine cervical carcinoma with granulocytosis as a paraneoplastic syndrome, however, has been rarely reported. We recently witnessed a case of invasive squamous cell carcinoma of the uterine cervix with granulocytosis. Leukocytosis developed up to 69,000/µL, and then normalized after chemo-radiotherapy. There was no evidence of infection, tumor necrosis, glucocorticoid administration, or myeloproliferative disease by examination of a bone marrow aspirate when granulocytosis appeared. This phenomenon was probably associated with the secretion of hematopoietic growth factors such as G-CSF, GM-CSF and IL-6 by the tumor. We suggest that, like some other solid tumors, cervical cancer can present with granulocytosis as a paraneoplastic syndrome.

Heme oxygenase-1 determines the differential response of breast cancer and normal cells to piperlongumine.

Piperlongumine, a natural alkaloid isolated from the long pepper, selectively increases reactive oxygen species production and apoptotic cell death in cancer cells but not in normal cells. However, the molecular mechanism underlying piperlongumine-induced selective killing of cancer cells remains unclear. In the present study, we observed that human breast cancer MCF-7 cells are sensitive to piperlongumine-induced apoptosis relative to human MCF-10A breast epithelial cells. Interestingly, this opposing effect of piperlongumine appears to be mediated by heme oxygenase-1 (HO-1). Piperlongumine upregulated HO-1 expression through the activation of nuclear factor-erythroid-2-related factor-2 (Nrf2) signaling in both MCF-7 and MCF-10A cells. However, knockdown of HO-1 expression and pharmacological inhibition of its activity abolished the ability of piperlongumine to induce apoptosis in MCF-7 cells, whereas those promoted apoptosis in MCF-10A cells, indicating that HO-1 has anti-tumor functions in cancer cells but cytoprotective functions in normal cells. Moreover, it was found that piperlongumine-induced Nrf2 activation, HO-1 expression and cancer cell apoptosis are not dependent on the generation of reactive oxygen species. Instead, piperlongumine, which bears electrophilic α,β-unsaturated carbonyl groups, appears to inactivate Kelch-like ECH-associated protein-1 (Keap1) through thiol modification, thereby activating the Nrf2/HO-1 pathway and subsequently upregulating HO-1 expression, which accounts for piperlongumine-induced apoptosis in cancer cells. Taken together, these findings suggest that direct interaction of piperlongumine with Keap1 leads to the upregulation of Nrf2-mediated HO-1 expression, and HO-1 determines the differential response of breast normal cells and cancer cells to piperlongumine.

Piperlongumine induces cell death through ROS-mediated CHOP activation and potentiates TRAIL-induced cell death in breast cancer cells

AbstractPurpose Piperlongumine (PL) has been shown to selectively induce apoptotic cell death in cancer cells via reactive oxygen species (ROS) accumulation. In this study, we characterized a molecular mechanism for PL-induced cell death.MethodsCell viability and cell death were assessed by MTT assay and Annexin V-FITC/PI staining, respectively. ROS generation was measured using the H2DCFDA. Small interfering RNA (siRNA) was used for suppressing gene expression. The mRNA and protein expression were analyzed by RT-PCR and Western blot analysis, respectively.ResultsWe found that PL promotes C/EBP homologous protein (CHOP) induction, which leads to the up-regulation of its targets Bim and DR5. Pretreatment with the ROS scavenger N-acetyl-cysteine abolishes the PL-induced up-regulation of CHOP and its target genes, suggesting an essential role for ROS in PL-induced CHOP activation. The down-regulation of CHOP or Bim with siRNA efficiently attenuates PL-induced cell death, suggesting a critical role for CHOP in this cell death. Furthermore, PL potentiates TRAIL-induced cytotoxicity in breast cancer cells by upregulating DR5, as DR5 knockdown abolished the sensitizing effect of PL on TRAIL responses.ConclusionsOverall, our data suggest a new mechanism for the PL-induced cell death in which ROS mediates CHOP activation, and combination treatment with PL and TRAIL could be a potential strategy for breast cancer therapy.

Blockage of Stat3 enhances the sensitivity of NSCLC cells to PI3K/mTOR inhibition

The PI3K/Akt/mTOR axis in lung cancer is frequently activated and implicated in tumorigenesis. Specific targeting of this pathway is therefore an attractive therapeutic approach for lung cancer. However, non-small cell lung cancer cells are resistant to BEZ235, a dual inhibitor of PI3K and mTOR. Interestingly, blockage of Stat3 with a selective inhibitor, S3I-201, or siRNA dramatically sensitized the BEZ235-induced cell death, as evident from increased PARP cleavage. Furthermore, inhibition of Stat3 led to enhancement of cell death induced by LY294002, a PI3K inhibitor. Treatment of cells with a combination of BEZ235 and S3I-201 significantly induced the proapoptotic transcription factor, CHOP, and its targets, Bim and DR4. Knockdown of CHOP or Bim suppressed cell death stimulated by the combination treatment, implicating the involvement of these BEZ235/S3I-201-induced factors in pronounced cell death. Moreover, the BEZ235/S3I-201 combination enhanced TRAIL-induced cell death. Our results collectively suggest that blockage of Stat3 presents an effective strategy to overcome resistance to PI3K/Akt/mTOR inhibition.

Elective High-Frequency Oscillatory Ventilation versus Conventional Ventilation for Acute Pulmonary Dysfunction in Preterm Infants

BACKGROUND Respiratory failure due to lung immaturity is a major cause of mortality in preterm infants. Although the use of intermittent positive pressure ventilation in neonates with respiratory failure saves lives, its use is associated with lung injury and chronic lung disease (CLD). A newer form of ventilation called high-frequency oscillatory ventilation (HFOV) has been shown to result in less lung injury in experimental studies. OBJECTIVES The objective of this review is to determine the effect of the elective use of HFOV as compared to conventional ventilation (CV) on the incidence of CLD, mortality and other complications associated with prematurity and assisted ventilation in preterm infants who are mechanically ventilated for respiratory distress syndrome (RDS). SEARCH METHODS Searches were made of the Oxford Database of Perinatal Trials, MEDLINE, EMBASE, previous reviews including cross-references, abstracts, conferences and symposia proceedings, expert informants, journal hand searching by the Cochrane Collaboration, mainly in the English language. The search was updated in January 2009. SELECTION CRITERIA Randomized controlled trials comparing HFOV and CV in preterm or low birth weight infants with pulmonary dysfunction, mainly due to RDS, who required assisted ventilation. Randomization and commencement of treatment needed to be as soon as possible after the start of CV and usually in the first 12 h of life. DATA COLLECTION AND ANALYSIS The methodological quality of each trial was independently reviewed by the various authors. The standard effect measures are relative risk (RR) and risk difference (RD). From 1/RD the number needed to treat to produce one outcome were calculated. For all measures of effect, 95% confidence intervals were used. In subgroup analyses the 99% CIs are also given for summary RRs in the text. Meta-analysis was performed using a fixed effect model. Where heterogeneity was over 50%, the random effects RR is also given. MAIN RESULTS Seventeen eligible studies of 3,652 infants were included. Meta-analysis comparing HFOV with CV revealed no evidence of effect on mortality at 28-30 days of age or at approximately term equivalent age. These results were consistent across studies and in subgroup analyses. The effect of HFOV on CLD in survivors at term equivalent gestational age was inconsistent across studies and the reduction was of borderline significance overall. The effect was similar in trials with a high lung volume strategy for HFOV targeting at very low FiO(2) and trials with a high lung volume strategy with somewhat higher or unspecified target FiO(2). Subgroups of trials showed a significant reduction in CLD with HFOV when no surfactant was used, when piston oscillators were used for HFOV, when lung protective strategies for CV were not used, when randomization occurred at two to six hours of age, and when inspiratory:expiratory ratio of 1:2 was used for HFOV. In the meta-analysis of all trials, pulmonary air leaks occurred more frequently in the HFOV group. In some studies, short-term neurological morbidity with HFOV was found, but this effect was not statistically significant overall. The subgroup of two trials not using a high-volume strategy with HFOV found increased rates of grade 3 or 4 intraventricular hemorrhage and of periventricular leukomalacia. An adverse effect of HFOV on long-term neurodevelopment was found in one large trial but not in the five other trials that reported this outcome. The rate of retinopathy of prematurity is reduced overall in the HFOV group.

Clinical utility of the Xpert MRSA assay for early detection of methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for many nosocomial and community-acquired infections, resulting in significant morbidity and mortality. A practical way to limit the spread of MRSA is early detection and proper treatment. However, screening culture for MRSA typically requires 2–3 days. The Xpert MRSA assay (Cepheid, Sunnyvale, CA, USA) is a real-time polymerase chain reaction-based assay developed for screening an MRSA-specific DNA sequence within the staphylococcal cassette chromosome in 2 h. Lower respiratory tract specimens, such as transtracheal aspirates (TTAs) and bronchoalveolar lavage fluid (BALF), are commonly obtained from intubated patients. Therefore, using the lower respiratory tract specimens with the Xpert MRSA assay may be a practical tool for patient care. We performed the Xpert MRSA assay on 108 TTA and 21 BALF specimens from 92 patients and compared the results to those obtained by culture. The two assays showed concordant results in 120 (93.0%) cases and discordant results in 9 (7.0%) cases, which were culture-negative and Xpert MRSA-positive. Among the discordant cases, 5 patients developed culture-positive samples 2–15 days after the Xpert MRSA detected MRSA. We conclude that the Xpert MRSA assay is a rapid, sensitive and clinically useful test, particularly for the early detection of MRSA.

Inhibition of vacuolar H+ ATPase enhances sensitivity to tamoxifen via up-regulation of CHOP in breast cancer cells.

Resistance of estrogen receptor-positive breast cancer cells to tamoxifen represents a major barrier to the successful treatment of breast cancer. In the present study, we found that vacuolar H+ ATPase (vATPase) inhibitors, bafilomycin A1 and concanamycin A, sensitize tamoxifen-induced cell death. siRNA targeting ATP6V0C, a 16-kDa hydrophobic proteolipid subunit of vATPase that plays a central role in H+ transport, markedly increased cell death induced by tamoxifen. Interestingly, bafilomycin A1 induced up-regulation of DR4/DR5 and CHOP. Knock-down of CHOP by siRNA suppressed the cell death induced by bafilomycin A1 and tamoxifen, suggesting that bafilomycin A1-mediated CHOP activation sensitizes to tamoxifen. In addition, we found that bafilomycin A1 enhances TRAIL-induced cell death in breast cancer cells. Furthermore, we showed that combination of vATPase inhibitors with tamoxifen also effectively induced cell death in HER2- and ERα-overexpressing breast cancer cells. Overall, our results demonstrate that inhibition of vATPase can potentiate the apoptotic effects of tamoxifen through up-regulation of CHOP.