Dong Soon Lee

Bortezomib inhibits tumor adaptation to hypoxia by stimulating the FIH-mediated repression of hypoxia-inducible factor-1

Bortezomib (PS-341), a proteasome inhibitor, has been examined clinically for the treatment of multiple myeloma and several solid tumors. Bortezomib directly induces tumor cell death and has also been reported to inhibit tumor adaptation to hypoxia by functionally inhibiting hypoxia-inducible factor-1alpha (HIF-1alpha). However, the mechanism underlying HIF-1 inhibition by bortezomib remains obscure. In the present study, we demonstrated that bortezomib attenuated the hypoxic induction of erythropoietin and vascular endothelial growth factor at subnanomolar concentrations in multiple myeloma and liver cancer cell lines, regardless of cytotoxic concentrations of bortezomib. Bortezomib repressed HIF-1alpha activity by inhibiting the recruitment of p300 coactivator. Specifically, bortezomib targeted HIF-1alpha C-terminal transactivation domain (CAD) but not the CAD lacking Asn803, which is a hydroxylation site by the factor inhibiting HIF-1 (FIH). Accordingly, this effect of bortezomib on CAD was augmented by FIH expression and abolished by FIH knock-down. Furthermore, bortezomib stimulated the interaction between CAD and FIH under hypoxic conditions, and FIH inhibition reversed the suppressions of erythropoietin and vascular endothelial growth factor by bortezomib. We propose that the mechanism underlying the inhibitory effects of bortezomib on tumor angiogenesis and hypoxic adaptation involves the repression of HIF-1alpha transcriptional activity by reinforcing the FIH-mediated inhibition of p300 recruitment.

Dopamine transporter density is decreased in parkinsonian patients with a history of manganese exposure: What does it mean?

Manganese (Mn) exposure can cause parkinsonism. Pathological changes occur mostly in the pallidum and striatum. Two patients with a long history of occupational Mn exposure presented with Mn‐induced parkinsonism. In one patient, magnetic resonance imaging (MRI) showed findings consistent with Mn exposure, and Mn concentration was increased in the blood and urine. However, this patients clinical features were typical of idiopathic Parkinson disease (PD). Previous pathological and positron emission tomography studies indicate that striatal dopamine transporter density is normal in Mn‐induced parkinsonism, whereas it is decreased in PD. Therefore, we performed [123I]‐(1r)‐2β‐carboxymethoxy‐3β‐(4‐iodophenyl)tropane ([123I]‐β‐CIT) single‐photon emission computed tomography. Severe reduction of striatal β‐CIT binding was indicated, which is consistent with PD. We propose three interpretations: (1) the patients have PD, and Mn exposure is incidental; (2) Mn induces selective degeneration of presynaptic dopaminergic nerve terminals, thereby causing parkinsonism; or (3) Mn exposure acts as a risk of PD in these patients. Our results and careful review of previous studies indicate that the axiom that Mn causes parkinsonism by pallidal lesion may be over‐simplified; Mn exposure and parkinsonism may be more complex than previously thought. Further studies are required to elucidate the relationship between Mn and various forms of parkinsonism.

Homozygous deletion of CDKN2A (p16, p14) and CDKN2B (p15) genes is a poor prognostic factor in adult but not in childhood B-lineage acute lymphoblastic leukemia: a comparative deletion and hypermethylation study

The biological behavior of childhood B-lineage acute lymphoblastic leukemia (B-ALL) is different from that of adults. We performed a comprehensive analysis of the deletion and the methylation profile of CDKN2A (hereafter identified separately as p16 and p14, for the different proteins encoded) and CDKN2B (hereafter p15) in 91 newly diagnosed B-ALL patients (61 children, 30 adults). The prognostic significance of the profiles of these genes and the association between alterations in these genes and known cytogenetic prognostic factors (BCR/ABL; ETV6/RUNX1, formerly TEL/AML1; MLL rearrangement; and ploidy changes of chromosomes) were also assessed. The prevalence of homozygous deletion, hemizygous deletion, and no deletion of the 9p21 region was 11.5%, 16.4%, and 72.1%, respectively, in children and 30.0%, 20.0%, and 50.0%, respectively, in adults; the higher incidence of homozygous deletion in adults was significant (P=0.029). Homozygous deletion was associated with poor overall survival in adults (P=0.019), but not in children. The incidence of promoter methylation of p16, p14, and p15 was 34.4%, 14.8%, and 34.4%, respectively, in children and 26.7%, 10.0%, and 40.0%, respectively, in adults, with no significant difference between the two groups. No significant association was observed between deletion and methylation or with known cytogenetic prognostic factors. The difference in incidence, distribution, and prognostic effect of homozygous deletion in children and adults may explain the prognostic disparity.

The number of CD8+ T cells and NKT cells increases in the aqueous humor of patients with Behçet's uveitis

To determine whether there are differences in the immunopathogenesis of different endogenous uveitis syndromes, the phenotypic characteristics of immune cells were analysed among patients with endogenous uveitis. The aetiology of the uveitis included idiopathic recurrent acute anterior uveitis (18 patients), idiopathic intermediate uveitis (13 patients), Behçets uveitis (17 patients), Vogt–Koyanagi–Harada syndrome (7 patients), and so on. Flow cytometric analysis was performed using immune cells of the aqueous humor and the peripheral blood during the active phase of intraocular inflammation, and monoclonal antibodies to CD3, CD4, CD8, CD14, CD19, CD56, TCR γδ, pan TCR αβ and Vα24. CD8+ T cells were predominant in the aqueous humor of the patients with Behçets uveitis, whereas CD4+ T cells were mainly found in the aqueous humor of patients other than those with Behçets uveitis. The number of NKT (CD3+CD56+) cells was significantly higher both in the aqueous humor and the peripheral blood of the patients with Behçets uveitis compared with the other groups (P < 0·05). CD8+CD56+ cells were the predominant subtype of the increased NKT cells in patients with Behçets uveitis. In addition, intraocular infiltration of CD14+ cells significantly differed among the uveitis patients (P < 0·05). These results suggest that the immunopathogenesis of endogenous uveitis can vary between syndromes, and that CD8+CD56+ NKT cells may play an important role in the immunopathogenesis of Behçets uveitis.

Predominance of trisomy 1q in myelodysplastic syndromes in Korea: is there an ethnic difference? A 3-year multi-center study

A predominance of total or partial chromosomal losses and the rarity of translocations are characteristics of myelodysplastic syndrome (MDS), and 5q,-5, -7 and +8 are known to be the most predominant chromosomal changes. To investigate whether the incidence and the pattern of chromosomal changes in MDS varies by location in Korea, we reviewed the cytogenetic results of 205 MDS cases from three medical centers. Distribution of MDS subtypes and the incidence of chromosomal aberration (44.8%) of MDS in Korea were similar to those found in other countries, however, their patterns were different. Translocations (40.4%) predominated over partial or total deletions (36.3%) in Korea. The most common abnormalities in MDS were trisomy 8, trisomy 1q, -5/5q-, and -7/7q-, which occurred in 18(19.5%), 14(15.2%), 12(13.0%), and 11(11.9%) patients, respectively. It is of note that trisomy 1q, which is rarely reported in hematologic malignancies, was the second most common change associated with MDS in Korea, and that structural anomalies of chromosomes 1(19.6%) exceeded that of chromosome 5(15.2%). The most common sole anomalies were trisomy 8(7.6%) and 14(78%) of 18 cases with chromosome 1 anomalies accompanied by other chromosomal abnormalities, suggesting that the changes of chromosome 1 may be evolutionary events rather than sporadic events. In conclusion, trisomy 1q and trisomy 8 predominate in Korean MDS, suggesting the likelihood of ethnic differences.

A study on the incidence of ABL gene deletion on derivative chromosome 9 in chronic myelogenous leukemia by interphase fluorescence in situ hybridization and its association with disease progression.

Fluorescence in situ hybridization for the BCR/ABL rearrangement in 138 bone marrow specimens from 59 Philadelphia+ (Ph+) chronic myelogenous leukemia (CML) patients, 35 Ph+ acute lymphoblastic leukemia (ALL) patients, and 57 Ph− ALL patients was used. Sixteen (27.1%) of the 59 CML patients had deletions of the residual ABL gene on the derivative chromosome 9. During the study period, 32 of the 59 CML patients progressed to blast crisis or accelerated phase. Of these, nine patients had residual ABL gene deletions on the derivative chromosomes 9 and 23 patients had no deletions. The mean duration from first diagnosis to blast crisis or accelerated phase for the nine patients with ABL deletions was 32.8 months, and for the 23 patients without ABL deletions, it was 62.4 months (P = 0.017). The overall survival time for the 16 patients with deletions was 32.8 months, and for the 43 patients without deletions, it was 60.1 months (P = 0.164). ABL deletions were not detected among the 35 ALL patients (17 with major BCR/ABL, 18 with minor BCR/ABL), and it appears that this deletion occurs rarely or not at all in Ph+ ALL patients, which is in contrast to the CML patients (27.1%). However, we detected two ALL cases with ABL deletion but without BCR/ABL rearrangement among 49 Ph− ALL and 66 Ph− AML patients. In conclusion, patients with ABL deletions progress to blast crisis or accelerated phase in a significantly shorter time than do those without such deletions. It is therefore suggested that the ABL deletion is an indicator of a poor prognosis in CML.

Granulocytic Sarcoma in MLL-Positive Infant Acute Myelogenous Leukemia : Fluorescence in Situ Hybridization Study of Childhood Acute Myelogenous Leukemia for Detecting MLL Rearrangement

Granulocytic sarcoma is considered to be rare and its frequent occurrence is associated with specific genetic changes such as t(8;21). To investigate an association between MLL (mixed lineage leukemia or myeloid-lymphoid leukemia) rearrangement and granulocytic sarcoma, we applied fluorescence in situ hybridization for detection of the 11q23/MLL rearrangements on the bone marrow cells of 40 patients with childhood acute myelogenous leukemia (AML). Nine (22.5%) of 40 patients exhibited MLL rearrangements. Three (33.3%) of these nine patients had granulocytic sarcoma and were younger than 12 months of age. Of these three patients one presented as granulocytic sarcoma of both testes with cerebrospinal fluid involvement, the second case presented in the form of an abdominal mass, and the third as a periorbital granulocytic sarcoma. On the other hand, no granulocytic sarcomas were found among MLL-negative patients. It is likely that MLL-positive infant AML may predispose granulocytic sarcoma. Regarding the findings of our study and those of other reports, we would guess that the incidence of granulocytic sarcoma in pediatric MLL-positive AML may be equal to or greater than the 18 to 24% described in AML with t(8;21). Further investigations designed to identify 11q23/MLL abnormalities of leukemic cells or extramedullary tumor may be helpful for the precise diagnosis of granulocytic sarcoma.

CALR, JAK2, and MPL Mutation Profiles in Patients With Four Different Subtypes of Myeloproliferative Neoplasms

OBJECTIVES We investigated mutation profiles of CALR, JAK2, and MPL in 199 Korean patients with myeloproliferative neoplasms (MPNs). METHODS In total, 199 patients with MPN (54 primary myelofibrosis [PMF], 79 essential thrombocythemia [ET], 58 polycythemia vera [PV], and eight MPN-unclassifiable [MPN-U]) and 4 patients with acute panmyelosis with myelofibrosis (APMF) were retrospectively subjected to Sanger sequencing for CALR, JAK2, and MPL. RESULTS The overall frequency of CALR mutations was 12.6% (type 1 mutation, 16 patients; type 2 mutation, nine patients): most frequent in MPN-U (37.5%), followed by ET (17.7%) and PMF (14.8%). CALR mutations were not found in PV or APMF. CALR and JAK2 or MPL mutations were mutually exclusive. In PMF, the CALR mutations were associated with lower levels of leukocytes, lower bone marrow cellularity, and higher number of megakaryocytes. Patients with CALR-mutated ET more frequently progressed to the accelerated or blast phases compared with patients with JAK2 mutations. CALR mutations were frequently observed in the JAK2-negative MPNs, most frequently in MPN-U. CONCLUSIONS The prognostic significance of CALR mutations likely differs among the MPN subtypes.

Low incidence of TEL/AML1 fusion and TEL deletion in Korean childhood acute leukemia by extra-signal fluorescence in situ hybridization.

TEL/AML1 fusion in acute leukemia results from cryptic translocation of chromosome 12 and 21, the presence of which suggests a favorable prognosis. The incidence of TEL/AML1 fusion in B-lineage ALL is approximately 25%, but the incidence in Korea has not yet been reported. To investigate the incidence of TEL/AML1 fusion and TEL deletion, bone marrow specimens from 77 Korean children with newly diagnosed acute leukemia were analyzed by FISH. We applied extra-signal FISH to discriminate a true TEL/AML1 fusion from a false-positive fusion signal. To determine the cut-off value of the TEL/AML1 fusion signal, 20 normal bone marrow specimens and 28 normal peripheral blood specimens were also analyzed. The frequency of patients with TEL/AML1 fusion was 13.3% (4 cases) among 30 B-lineage ALL and 9.5% among 42 ALL. One TEL/AML1 fusion-positive patient was also found among 4 acute biphenotypic leukemias. TEL/AML1 fusion was not found in any samples from patients with T-lineage ALL or AML. The incidence of TEL deletion was 6.7% (2 cases) among 30 B-lineage ALL and 4.8% among 42 ALL. The incidences of TEL/AML1 fusion and TEL deletion in Korean children with acute leukemia appear to be lower than those in other countries, suggesting a racial difference.

Erythrocyte Sedimentation Rate Measurements by TEST 1 Better Reflect Inflammation Than Do Those by the Westergren Method in Patients With Malignancy, Autoimmune Disease, or Infection

We compared the TEST 1 (Alifax, Padova, Italy) and Westergren methods of measuring the erythrocyte sedimentation rate (ESR) to assess inflammation. The ESR was measured by both methods in 154 blood samples from patients with malignancy (n = 69), autoimmune disease (n = 44), or infection (n = 41). Total protein, albumin, and C-reactive protein (CRP) levels were measured in each plasma sample, and albumin and alpha(1)-, alpha(2)-, beta(1)-, beta(2)-, and gamma-globulin fractions were measured by capillary electrophoresis. TEST 1 ESR values were significantly lower than the Westergren values, by 10.9 mm/h. We found that the correlations of TEST 1 ESR values with inflammatory protein levels (total protein, globulin, CRP, and alpha(1)-, alpha(2)-, beta(2)-, and gamma-globulin) were better than those obtained using the Westergren method. These findings indicate that ESR measurements by TEST 1 reflect inflammation better than do those by the Westergren method in patients with malignancy, autoimmune disease, or infection.