Synthesis of Multisubstituted Aromatics via 3-Triazenylarynes

An efficient method for generating 3-triazenylarynes from ortho-iodoaryl triflate-type precursors was developed. The generated arynes reacted with various arynophiles with high regioselectivity because of the triazenyl group. The 3-triazenylaryne precursors functioned as useful intermediates of diverse multisubstituted aromatic compounds through the transformation of the remaining triazenyl group of aryne adducts and triazenyl group-directed ortho-C-H functionalization.

Efficient simultaneous double DNA knock-in in murine embryonic stem cells by CRISPR/Cas9 ribonucleoprotein-mediated circular plasmid targeting for generating gene-manipulated mice

Gene targeting of embryonic stem (ES) cells followed by chimera production has been conventionally used for developing gene-manipulated mice. Although direct knock-in (KI) using murine zygote via CRISPR/Cas9-mediated genome editing has been reported, ES cell targeting still has merits, e.g., high throughput work can be performed in vitro. In this study, we first compared the KI efficiency of mouse ES cells with CRISPR/Cas9 expression vector and ribonucleoprotein (RNP), and confirmed that KI efficiency was significantly increased by using RNP. Using CRISPR/Cas9 RNP and circular plasmid with homologous arms as a targeting vector, knock-in within ES cell clones could be obtained efficiently without drug selection, thus potentially shortening the vector construction or cell culture period. Moreover, by incorporating a drug-resistant cassette into the targeting vectors, double DNA KI can be simultaneously achieved at high efficiency by a single electroporation. This technique will help to facilitate the production of genetically modified mouse models that are fundamental for exploring topics related to human and mammalian biology.

MYCL-mediated reprogramming expands pancreatic insulin-producing cells

β cells have a limited capacity for regeneration, which predisposes towards diabetes. Here, we show that, of the MYC family members, Mycl plays a key role in proliferation of pancreatic endocrine cells. Genetic ablation of Mycl causes a reduction in the proliferation of pancreatic endocrine cells in neonatal mice. By contrast, the expression of Mycl in adult mice stimulates the proliferation of β and α cells, and the cells persist after withdrawal of Mycl expression. A subset of the expanded α cells give rise to insulin-producing cells after this withdrawal. Transient Mycl expression in vivo is sufficient to normalize the hyperglycaemia of diabetic mice. In vitro expression of Mycl similarly provokes active replication in islet cells, even in those from aged mice. Finally, we show that MYCL stimulates the division of human adult cadaveric islet cells. Our results demonstrate that the induction of Mycl alone expands the functional β-cell population, which may provide a regenerative strategy for β cells.

DMRT1-mediated reprogramming drives development of cancer resembling human germ cell tumors with features of totipotency

In vivo reprogramming provokes a wide range of cell fate conversion. Here, we discover that in vivo induction of higher levels of OSKM in mouse somatic cells leads to increased expression of primordial germ cell (PGC)-related genes and provokes genome-wide erasure of genomic imprinting, which takes place exclusively in PGCs. Moreover, the in vivo OSKM reprogramming results in development of cancer that resembles human germ cell tumors. Like a subgroup of germ cell tumors, propagated tumor cells can differentiate into trophoblasts. Moreover, these tumor cells give rise to induced pluripotent stem cells (iPSCs) with expanded differentiation potential into trophoblasts. Remarkably, the tumor-derived iPSCs are able to contribute to non-neoplastic somatic cells in adult mice. Mechanistically, DMRT1, which is expressed in PGCs, drives the reprogramming and propagation of the tumor cells in vivo. Furthermore, the DMRT1-related epigenetic landscape is associated with trophoblast competence of the reprogrammed cells and provides a therapeutic target for germ cell tumors. These results reveal an unappreciated route for somatic cell reprogramming and underscore the impact of reprogramming in development of germ cell tumors.

Chiral deaza-coelenterazine analogs for probing a substrate-binding site in the Ca2+-binding photoprotein aequorin

The Ca²⁺-binding photoprotein aequorin is a complex of apoAequorin (apoprotein) and (S)-2-peroxycoelenterazine. Aequorin can be regenerated by the incubation of apoAequorin with coelenterazine and molecular oxygen (O₂). In this study, to investigate the molecular recognition of apoAequorin for coelenterazine using chemical probes, the chiral deaza-analogs of (S)- and (R)-deaza-CTZ (daCTZ) for coelenterazine and of (S)-2- and (R)-2-hydroxymethyl-deaza-CTZ (HM-daCTZ) for 2-peroxycoelenterazine were efficiently prepared by the improvement method. The chiral deaza-analogs of (S)-daCTZ and (S)-HM-daCTZ selectively inhibited the regeneration step to aequorin by binding the catalytic site of coelenterazine in the apoAequorin molecule. The crystal structures of the apoAequorin complexes with (S)-daCTZ and (S)-HM-daCTZ were determined, suggesting that the hydroxy moiety at the C6-hydroxyphenyl group and the carbonyl moiety of the imidazopyrazinone ring in coelenterazine are essential to bind the apoAequorin molecule through hydrogen bonding. Therefore, the chiral deaza-analogs of coelenterazine can be used as a probe to study the interaction between coelenterazine and the related proteins including photoprotein, luciferase, and coelenterazine-binding protein.

Identification of a novel oxidation product from yellow fluorophore in the complex of apoPholasin and dehydrocoelenterazine

The complex of the recombinant fusion protein of apoPholasin and glutathione S-transferase (GST-apoPholasin) with non-fluorescent dehydrocoelenterazine (dCTZ) (GST-apoPholasin/dCTZ complex) shows yellow fluorescence at 539 nm by excitation at 430 nm. The GST-apoPholasin/dCTZ complex with a fluorophore (dCTZ*) has considerably weak luminescence activity, converting slowly to a blue fluorescence protein with the emission peak at 430 nm. The main oxidation products from dCTZ* for blue fluorescence were identified as coelenteramine (CTM) and an unreported pyrazine derivative, 3-benzyl-5-(4-hydroxyphenyl)pyrazin-2(1H)-one (CTO) that was confirmed by chemical synthesis.

Synthesis of Acylboron Compounds

Acylboron compounds are emerging as versatile functional groups with applications in multiple research fields. Their synthesis, however, is still challenging and requires innovative methods. This Minireview provides an overview on the obstacles of acylboron synthesis and highlights notable advances within the last three years on new strategies to overcome the challenges posed by the formation of acyl-boron bonds.

Synthesis and Tunable Optical Properties of C,N-Chelated Borate Luminophores Derived from Potassium Acyltrifluoroborates

A new class of borate luminophores has been synthesized by a simple two-step reaction using potassium acyltrifluoroborates (KATs) as starting materials. The hydrazones obtained from reactions between KATs and 2-hydrazinopyridines followed by a cyclization resulted in the unprecedented formation of C,N-chelated six-membered bora-heterocycles. Under consideration of the results of DFT and TD-DFT calculations, four luminophores based on such bora-heterocycles are designed and synthesized, which exhibit a tunable fluorescence range from blue to red in the solid state. Moreover, one of the luminophores exhibits mechanofluorochromism from blue to yellow/green. As a result of the aforementioned mechanochromism of one of these luminophores, white-color emission was achieved by simply mixing the four luminophores.

Concise Synthesis of Potassium Acyltrifluoroborates from Aldehydes through Copper(I)-Catalyzed Borylation/Oxidation

Potassium acyltrifluoroborates (KATs) were prepared through copper(I)-catalyzed borylation of aldehydes and subsequent oxidation. This synthetic route is characterized by the wide range of aldehydes accessible, favorable step economy, mild reaction conditions, and tolerance of various functional groups, and it enables the facile generation of a range of KATs, for example, bearing halide, sulfide, acetal, or ester moieties. Moreover, this method was applied to the three-step synthesis of various α-amino acid analogues that bear a KAT moiety on the C-terminus by using naturally occurring amino acids as the starting material.

In vivo reprogramming for tissue regeneration and organismal rejuvenation

Transcription factor-mediated reprogramming has enabled us to induce the fate conversion of somatic cells into other cell types. Although the study of reprogramming mostly occurs at the cellular level in vitro, previous studies have demonstrated that somatic cells are reprogrammable in multicellular organisms too. Recent studies using in vivo reprogramming have provided important insights on regenerative medicine for diseased organs. Moreover, similar studies have revealed unappreciated mechanisms in various biological phenomena, including tissue regeneration, aging, rejuvenation and cancer development in multicellular organisms. Here, we review recent progress and future perspectives of in vivo reprogramming.

Abstract 921: Cdyl2 is a chromodomain protein involved in the maintenance of pluripotency of stem cells

Reader proteins of histone modifications are required to translate the information of histone marks into the cellular phenotypes, including pluripotency and malignancy. For example, a reader protein BRD4 has its target specificity and becomes a target of cancer therapy. Here, we aimed to identify reader proteins involved in the pluripotency of stem cells. Using the UCSC database, 11 genes coding chromo- or PHD-domain proteins were isolated as actively transcribed in mouse ES cells (ESCs). Among the 11 genes, Cdyl2, chromodomain protein Y-like2, was found to be down-regulated upon ESC differentiation using RT-qPCR. Immunofluorescence and ChIP assay revealed that Cdyl2 recognized H3K27me3 of the specific regions, including differentiation-associated genes. Cdyl2-knock-out ESCs could not survive after differentiation induced by LIF removal or retinoic acid because of the induction of apoptosis, indicating that Cdyl2 is important for normal differentiation of ESCs. ESC expressing exogenous Cdyl2 showed incomplete down-regulation of Oct-4 and Nanog by retinoic acid, and generated teratomas with an abnormal composition of three germ layers, showing perturbation of differentiation ability. Pathologically, aberrant expression of human CDYL2 was observed in breast cancer cell lines and primary breast cancers. Two breast cancer cell lines (MDA-MB-231 and MDA-MB-468) expressing exogenous CDYL2 showed enhanced attachment ability along with the up-regulation of integrin alpha-6 and integrin beta-1. The population of cancer stem cells, defined as ALDH positive cells, were increased in CDYL2-expressing MDA-MB-468 cells, showing that human CDYL2 is involved in proliferation of cancer stem cells. From these data, we conclude that, between self-renewal and differentiation of stem cells, mouse and human Cdyl2/CDYL2 is necessary for the implementation of the initial step of differentiation.

Citation Format: Naoko Hattori, Kana Kimura, Jumpei Taguchi, Toshio Imai, Yasuhiro Yamada, Toshikazu Ushijima. Cdyl2 is a chromodomain protein involved in the maintenance of pluripotency of stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 921. doi:10.1158/1538-7445.AM2017-921

Abstract P1-12-07: Phase Ib/II single-arm trial evaluating the combination of everolimus, lapatinib and capecitabine for the treatment of patients with HER2-positive metastatic breast cancer with progression in the CNS after trastuzumab (TRIO-US B-09)

Background: Improving outcomes for patients with HER2+ CNS metastases remains an unmet clinical need. Lapatinib (L) plus capecitabine (C) yields a 20% objective response rate (ORR) in the CNS in patients with previously treated HER2+ breast cancer brain metastases (Lin N, Clin Cancer Res 2009). Everolimus (E), an oral inhibitor of the mammalian target of rapamycin (mTOR), penetrates into the CNS in murine xenograft models (Meikle L, J Neurosci 2008). TRIO-US B09 is an investigator-initiated trial evaluating the safety and clinical activity of the novel combination of L+C+E for the treatment of patients with HER2+ breast cancer brain metastases.

Methods: Patients with trastuzumab-pretreated, HER2+ metastatic breast cancer (MBC) with progression of disease (PD) in the brain and a measurable brain lesion participated. Patients were excluded if they had a prior mTOR inhibitor or an ECOG PS>2. Prior L and/or C, and prior surgery and/or radiation to the brain were allowed. The primary endpoint was CNS ORR at 12 weeks (cycle 3) by RECIST 1.1. Secondary endpoints included safety, progression-free survival, overall survival and extra-CNS ORR. To test the safety of the combination of L+C+E, a 3+3 dose escalation phase was conducted (starting doses: L 1000 mg QD, E 5 mg QD, C: 750 mg/m2 BID d1-14). Treatment was given Q21 days. Patients were evaluated for dose limiting toxicities during C1. Tumor imaging was conducted every 3 cycles. MRI of the brain was performed every 2 cycles through cycle 6 and then every 3 cycles. Neurological symptom assessment was conducted on day 1 of every cycle. Study participants continued to receive treatment until PD, unacceptable toxicity or withdrawal of consent for 12 mos.

Results: Nineteen patients were enrolled at 11 sites in the US and treated with at least one dose of study drug. Of 18 patients with data available, median age was 58.5 (45-68), median number of systemic therapies for MBC was 2 (0-6), and 94.4% had prior radiation and/or surgical resection of brain metastases. 10 patients participated in the dose escalation phase of the study. The maximum tolerated doses were determined to be L 1000 mg QD, E 10 mg QD + C 1000 mg/m2BID days 1-14; however, given tolerability concerns, dose expansion proceeded with Cohort 2 dose for C (750 mg/m2 BID d1-14). Of 17 eligible patients with imaging results available to date, 2 (12%) had a partial response in the CNS at week 12, one of whom continues on study (currently in cycle 13). Stable disease was observed in 7 patients. The most common grade 3/4 adverse events (AE) (CTCAE v4.0) related to E and/or L in 18 treated patients were anorexia (5.5%), dehydration (5.5%), diarrhea (17%), fatigue (5.5%), fever (5.5%) hyperglycemia (5.5%), hypokalemia (11%), and oral mucositis (17%).

Conclusions: This is the first report of this regimen for patients with HER2+ MBC to the brain. This regimen is generally well-tolerated and shows promising activity in the CNS of heavily pretreated patients. Final efficacy and toxicity analyses for all 19 patients will be presented.

Citation Format: Hurvitz SA, Martinez DA, Singh R, Taguchi J, Chan D, Dichmann R, Castrellon A, Barstis J, Hu E, Berkowitz J, Mani A, DiCarlo B, Smalberg I, Hobbs E, Slamon DJ. Phase Ib/II single-arm trial evaluating the combination of everolimus, lapatinib and capecitabine for the treatment of patients with HER2-positive metastatic breast cancer with progression in the CNS after trastuzumab (TRIO-US B-09) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-12-07.

Early application of related SCT might improve clinical outcome in adult T-cell leukemia/lymphoma

Allogeneic hematopoietic SCT (allo-HSCT) is a curative treatment for aggressive adult T-cell leukemia/lymphoma (ATLL). Considering the dismal prognosis associated with conventional chemotherapies, early application of allo-HSCT might be beneficial for patients with ATLL. However, no previous study has addressed the optimal timing of allo-HSCT from related donors. Hence, to evaluate the impact of timing of allo-HSCT for patients with ATLL, we retrospectively analyzed data from patients with ATLL who received an allo-HSCT from a related donor. The median age was 52 years. Patients were grouped according to the interval from diagnosis to allo-HSCT: early transplant group, <100 days, n=72; late transplant group, ⩾100 days, n=428. The corresponding constituents of disease status were not statistically different between the two groups (P=0.11). The probability of OS in the early transplant group was significantly higher than that in the late transplant group (4-year OS, 49.3% vs 31.2%). Multivariate analysis revealed that late allo-HSCT was an unfavorable prognostic factor for OS (hazard ratio, 1.46; 95% confidence interval (CI), 1.01-2.11; P=0.04). Despite the limitations of a retrospective study, it might be acceptable to consider early application of allo-HSCT for ATLL.

Successful treatment of toxoplasmic encephalitis diagnosed early by polymerase chain reaction after allogeneic hematopoietic stem cell transplantation: two case reports and review of the literature

Toxoplasmic encephalitis represents a rare, but often fatal infection after allogeneic hematopoietic stem cell transplantation. Polymerase chain reaction (PCR)-based preemptive therapy is considered promising for this disease, but is not routinely applied, especially in low seroprevalence countries including Japan. We encountered 2 cases of toxoplasmic encephalitis after transplantation that were successfully treated. The diagnosis of toxoplasmic encephalitis in these cases was confirmed by PCR testing when neurological symptoms were observed. Both patients received pyrimethamine and sulfadiazine treatments within 2 weeks of the development of neurological symptoms, and remained free of recurrence for 32 and 12 months. These results emphasized the importance of the PCR test and immediate treatment after diagnosis for the management of toxoplasmic encephalitis.

Catalyst-controlled regiodivergent C-H borylation of multifunctionalized heteroarenes by using iridium complexes

The regiodivergent C-H borylation of 2,5-disubstituted heteroarenes with bis(pinacolato)diboron was achieved by using iridium catalysts formed in situ from [Ir(OMe)(cod)]2 /dtbpy (cod=1,5-cyclooctadiene, dtbpy: 4,4'-di-tert-butyl-2,2'-bipyridine) or [Ir(OMe)(cod)]2 /2 AsPh3 . When [Ir(OMe)(cod)]2 /dtbpy was used as the catalyst, borylation at the 4-position proceeded selectively to afford 4-borylated products in high yields (dtbpy system A). The regioselectivity changed when the [Ir(OMe)(cod)]2 /2 AsPh3 catalyst was used; 3-borylated products were obtained in high yields with high regioselectivity (AsPh3 system B). The regioselectivity of borylation was easily controlled by changing the ligands. This reaction was used in the syntheses of two different bioactive compound analogues by using the same starting material.

Expression of myeloperoxidase in acute myeloid leukemia blasts mirrors the distinct DNA methylation pattern involving the downregulation of DNA methyltransferase DNMT3B

Myeloperoxidase (MPO) has been associated with both a myeloid lineage commitment and favorable prognosis in patients with acute myeloid leukemia (AML). DNA methyltransferase inhibitors (decitabine and zeburaline) induced MPO gene promoter demethylation and MPO gene transcription in AML cells with low MPO activity. Therefore, MPO gene transcription was directly and indirectly regulated by DNA methylation. A DNA methylation microarray subsequently revealed a distinct methylation pattern in 33 genes, including DNA methyltransferase 3 beta (DNMT3B), in CD34-positive cells obtained from AML patients with a high percentage of MPO-positive blasts. Based on the inverse relationship between the methylation status of DNMT3B and MPO, we found an inverse relationship between DNMT3B and MPO transcription levels in CD34-positive AML cells (P=0.0283). In addition, a distinct methylation pattern was observed in five genes related to myeloid differentiation or therapeutic sensitivity in CD34-positive cells from AML patients with a high percentage of MPO-positive blasts. Taken together, the results of the present study indicate that MPO may serve as an informative marker for identifying a distinct and crucial DNA methylation profile in CD34-positive AML cells.

Expression of myeloperoxidase enhances the chemosensitivity of leukemia cells through the generation of reactive oxygen species and the nitration of protein

Myeloperoxidase (MPO), a pivotal lineage marker for acute myeloid leukemia (AML), has been also shown to have a prognostic value: a high percentage of MPO-positive blasts correlates to favorable prognosis. To understand the relationship between the expression of MPO in leukemia cells and the response to chemotherapeutic agents, we established MPO-expressing K562 leukemia cell lines and then treated them with cytosine arabinocide (AraC). Cells expressing wild-type MPO, but not mutant MPO that could not mature, died earlier of apoptosis than control K562 cells. Reactive oxygen species (ROS) were generated more in leukemia cells expressing MPO, and the generation was abrogated by MPO inhibitors or antioxidants. Tyrosine nitration of cellular protein also increased more in MPO-expressing K562 cells than control cells after treatment with AraC. In clinical samples, CD34-positive AML cells from high-MPO cases showed a tendency to be sensitive to AraC in the colony-formation assay, and the generation of ROS and the nitration of protein were observed only when the percentage of MPO-expressing cells was high. These data suggest that MPO enhances the chemosensitivity of AML through the generation of ROS and the nitration of proteins.

Small number of HTLV-1-positive cells frequently remains during complete remission after allogeneic hematopoietic stem cell transplantation that are heterogeneous in origin among cases with adult T-cell leukemia/lymphoma

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can provide long-term remission for patients with adult T-cell leukemia/lymphoma (ATLL) caused by human retrovirus, human T-lymphocyte virus (HTLV-1). To understand how HTLV-1-positive cells including ATLL cells were suppressed by allo-HSCT, we examined HTLV-1 provirus load and residual ATLL cells in peripheral blood of transplant recipients using PCR-based tests. We found that the copy number of HTLV-1 genome, called provirus, became very small in number after allo-HSCT; however, in most cases, provirus did not disappear even among long-term survivors. Tumor-specific PCR tests demonstrated that most of HTLV-1-positive cells that remained long after transplantation were not primary ATLL cells but donor-derived HTLV-1-positive cells. We also found a case having very low amount of residual disease in peripheral blood even long after transplantation. There was only one recipient in whom we failed to show the presence of HTLV-1 genome and antibody against HTLV-1 even with an extensive search, which strongly suggested the elimination of HTLV-1 after allo-HSCT. These results demonstrated that after allo-HSCT the small amount of residual HTLV-1-positive cells were heterogeneous in origin and that long-term disease control for ATLL could be obtained without the complete elimination of HTLV-1.

A phase II study of neoadjuvant docetaxel/carboplatin with or without trastuzumab in locally advanced breast cancer: Response and cardiotoxicity

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Background: A phase II clinical trial was conducted to study the safety and efficacy of neoadjuvant docetaxel/carboplatin (T/C) with or without trastuzumab (H) in women with stage III breast cancer. Methods: Forty-eight of 75 planned primary breast cancer patients (T3 or T4, any N, M0), age between 18 and 80 have been enrolled. Four cycles of T (75 mg/m2) + C (AUC 6) were given every 3 weeks preoperatively. Patients with HER-2 amplified tumors (FISH +) were randomized to receive either weekly concurrent H or T/C alone preoperatively and T/C plus H postoperatively. Tumors were assessed clinically at baseline and after neoadjuvant therapy. Cardiac assessment consisted of medical history, EKG and LVEF (by echocardiogram or MUGA) at baseline and at the end of neoadjuvant chemotherapy. Results: Available data from 45 of 48 enrolled patients showed 49% (22 cases) with complete clinical response, with 54.5% being HER-2 (+) (12 cases). Stable disease was seen in one patient who was HER-2 (−) (2.2%). Of 37 with complete pathology verification, 11 (29.7%) showed pathologic complete response (pCR) of the primary tumor with 5 cases being HER-2 (+). Of the 22 HER-2 (+) cases that completed neoadjuvant treatment, 11 received T/C/H and 11 received T/C. pCR was noted in 36.4% of the T/C/H group and 9% of the T/C group. LVEF data is available from 43 patients during the neoadjuvant phase, showing 18.6% (8 cases) with decrease of ≥ 10% (5 patients in the T/C arm and 3 patients in the T/C/H arm), although none had cardiac symptoms or LVEF below the normal limit. Conclusions: T/C ± H is clinically active in patients with locally advanced breast cancer including a 30% pCR rate. The cardiotoxicity rates were comparable between patients who received T/C and T/C/H.

No significant financial relationships to disclose.

Human herpesvirus-6 encephalitis after unrelated cord blood transplantation

Here we describe 2 patients with acute leukemia in whom human herpesvirus-6 (HHV-6) encephalitis developed after cord blood transplantation. In patients 1 and 2, generalized seizure and coma developed on day 62 and day 15, respectively, after cord blood transplantation, which failed to engraft in patient 1. Magnetic resonance imaging (MRI) of patient 1's brain showed low-intensity signals at the gyri of the bilateral lateral lobes on T1-weighted images and high-intensity signals on T2-weighted images. MRI of patient 2's brain showed high-intensity signals in bilateral white matter on T2-weighted images and on fluid-attenuated inversion recovery (FLAIR) images. Cerebrospinal fluid examination revealed an increased protein level with pleocytosis in patient 1 and a normal protein level without pleocytosis in patient 2. Polymerase chain reaction analysis detected HHV-6 DNA in the cerebrospinal fluid of both patients. Patient 1 recovered after administration of gancyclovir for 3 weeks. However, she again suffered from encephalitis after discontinuation of gancyclovir, and died of sepsis. Patient 2 died from an anoxic brain caused by generalized seizure. When neurological symptoms and signs appear in hematopoietic stem cell transplantation recipients, we should consider HHV-6 encephalitis and promptly and empirically treat them with gancyclovir or foscarnet.

Thiotepa/cyclophosphamide/TBI as a conditioning regimen for allogeneic hematopoietic stem cell transplantation in patients with myelodysplastic syndrome

In all, 18 patients (30-56 years; median 49) with MDS underwent allogeneic HSCT from related (n=12) or unrelated (n=6) donors after a conditioning regimen comprising thiotepa, cyclophosphamide, and TBI. GVHD prophylaxis consisted of cyclosporine (n=15) or tacrolimus (n=3) with short-course methotrexate. Four patients had low-risk disease (refractory anemia or complete remission after chemotherapy) and 14 patients had high-risk disease (RAEB, RAEB-t, or AML). Grade II-IV acute GVHD developed in six patients and chronic GVHD in 10. With a median follow-up of 31 months, the 2-year survival probability is 75% for low-risk patients and 57% for high-risk patients. One patient died of leukemia and six of treatment-related causes. This conditioning regimen requires further study in patients with MDS.

Directed mutagenesis studies of the C-terminal fingerprint region of Bacillus subtilis pyrophosphatase

The sequence SRKKQxxP near the C-terminus is conserved in pyrophosphatases of the recently discovered family II and includes a triplet of positively charged residues, two of which (Arg295 and Lys296 in Bacillus subtilis pyrophosphatase) are part of the active site and one (Lys297) is not. The importance of this triplet for catalysis by B. subtilis pyrophosphatase has been estimated by mutational analysis. R295K and K296R substitutions were found to decrease the catalytic constant 650- and 280-fold, respectively, and decrease the pK(a) of the essential acidic group by 1.1 and 0.5, respectively. K297R substitution was found to increase the catalytic constant 4.7-fold and to markedly change the protein circular dichroism spectrum in the range 250-300 nm. These results, together with the results of theoretical modelling of the enzyme-substrate complex, provide support for the direct involvement of Arg295 and Lys296 in substrate binding in family II pyrophosphatases.

Primary carcinoid of the testis associated with carcinoid syndrome

Testicular carcinoid is a rare disease accounting for less than 1% of all testicular neoplasms. It rarely manifests symptoms of carcinoid syndrome. Recent reports have noted that only 1.1-3.1% of testicular carcinoid tumors are complicated by carcinoid syndrome. In general, large tumor size and the presence of carcinoid syndrome are features associated with a malignant course. In the present case, pathological findings revealed pure carcinoid of the testis without metastasis. Moreover, watery diarrhea due to carcinoid syndrome disappeared and the serum serotonin level normalized following orchiectomy. The patient was followed up for 12 months with whole body computed tomography scan and assessment of serotonin levels. To date, there is no evidence of tumor recurrence. These findings suggest that monitoring serum serotonin levels may be useful as a marker during follow up of this type of tumor.

[Successful second transplant from one-locus HLA-mismatched unrelated donor for graft rejection following initial transplant from another unrelated donor in a patient with chronic myelogenous leukemia]

We report a patient with chronic myelogenous leukemia who received a second transplant from a one-locus HLA-mismatched unrelated donor after rejection of an initial bone marrow graft. For the first transplant, HLAs were fully matched, conditioning with busulfan + cyclophosphamide (CY) was applied, and cyclosporin A + short-term methotrexate (sMTX) was used for prophylaxis against GVHD. A complete chimera was not obtained, and the graft was rejected on day 122. For the second transplant, there was a one-HLA locus (DR) mismatch, conditioning was done with total body irradiation + cytarabine + CY, and GVHD prophylaxis consisted of FK506 + sMTX. Engraftment was obtained on day 27, and no graft failure was occurred at the time of writing. This case suggests that strong immunosuppression may have prevented rejection of the second bone marrow graft.

Lecithinized copper, zinc-superoxide dismutase ameliorates ischemia-induced myocardial damage

We have reported that lecithin-conjugated recombinant human Cu, Zn-superoxide dismutase (lecithinized SOD) has greater pharmacological potency than unmodified SOD through an increase in cell membrane affinity and half-life in plasma. Recently, ischemia or hypoxia alone has been suggested to result in increased superoxide anions, which lead to apoptosis in cardiomyocytes. We tested the effect of lecithinized SOD in reducing the infarct size following prolonged myocardial ischemia without reperfusion. Rats were subjected to a 24-h left coronary occlusion. Lecithinized SOD, unmodified SOD, free lecithin derivative or PBS was administered intravenously 30 min before coronary occlusion. SOD concentration of the heart, measured by ELISA, was higher in the lecithinized SOD-treated group than in the other groups 24 h after administration. The infarct area ratio of the heart, assessed by TTC staining, in the lecithinized SOD-treated group was significantly smaller than those of the other groups. Both TUNEL-positive cardiomyocytes and DNA laddering were attenuated in the ischemic area of the heart treated with lecithinized SOD. Single bolus administration of lecithinized SOD had a cardioprotective effect against ischemia without reperfusion in the rat model of acute myocardial infarction, possibly due to its sustained high tissue concentration.

The interleukin-13 receptor alpha2 chain: an essential component for binding and internalization but not for interleukin-13-induced signal transduction through the STAT6 pathway

The interleukin-13 receptor (IL-13R) complex is composed of 2 different chains, IL-13Ralpha1 (also known as IL-13Ralpha') and IL-13Ralpha2 (also known as IL-13Ralpha). For a functional IL-13 receptor, the IL-13Ralpha1 chain forms a productive complex with the primary IL-4 binding protein (IL-4Ralpha also known as IL-4Rbeta). However, the function of the IL-13Ralpha2 chain is not clear even though this chain binds IL-13 with high affinity. This study demonstrates that IL-13Ralpha2 can undergo internalization after binding to ligand without causing activation of its signaling pathways. These conclusions were drawn on the basis of (1) internalization of (125)I-IL-13 in Chinese hamster ovarian (CHO-K1) and T98G glioblastoma cells transiently transfected with the IL-13Ralpha2 chain; (2) a recombinant chimeric fusion protein comprising IL-13 and a mutated form of Pseudomonas exotoxin (termed IL13-PE38QQR or IL-13 toxin) is specifically cytotoxic to IL-13Ralpha2-transfected CHO-K1 cells in a gene dose-dependent manner, whereas cells transfected with vector alone were not sensitive; and (3) IL-13 did not cause activation of signal transduction and activation of transcription 6 (STAT6) in IL-13Ralpha2-transfected cells. IL-13 efficiently caused activation of STAT6 protein in cells transfected with the IL-13Ralpha1 and IL-4Ralpha chains, and IL-13Ralpha2 inhibited this activation. Taken together, these observations indicate that internalization of IL-13Ralpha2 is signal independent and that this property of IL-13Ralpha2 can be exploited for receptor-directed cancer therapy.