Glutamine synthetase expression rescues human dendritic cell survival in a glutamine-deprived environment.

Introduction: Glutamine deficiency is a well-known feature of the tumor environment. Here we analyzed the impact of glutamine deprivation on human myeloid cell survival and function. Methods: Different types of myeloid cells were cultured in the absence or presence of glutamine and/or with L-methionine-S-sulfoximine (MSO), an irreversible glutamine synthetase (GS) inhibitor. GS expression was analyzed on mRNA and protein level. GS activity and the conversion of glutamate to glutamine by myeloid cells was followed by 13C tracing analyses. Results: The absence of extracellular glutamine only slightly affected postmitotic human monocyte to dendritic cell (DC) differentiation, function and survival. Similar results were obtained for monocyte-derived macrophages. In contrast, proliferation of the monocytic leukemia cell line THP-1 was significantly suppressed. While macrophages exhibited high constitutive GS expression, glutamine deprivation induced GS in DC and THP-1. Accordingly, proliferation of THP-1 was rescued by addition of the GS substrate glutamate and 13C tracing analyses revealed conversion of glutamate to glutamine. Supplementation with the GS inhibitor MSO reduced the survival of DC and macrophages and counteracted the proliferation rescue of THP-1 by glutamate. Discussion: Our results show that GS supports myeloid cell survival in a glutamine poor environment. Notably, in addition to suppressing proliferation and survival of tumor cells, the blockade of GS also targets immune cells such as DCs and macrophages.

Second Cancer After Additive Chemotherapy in Patients With Colon Cancer.

BACKGROUND: Additive chemotherapeutic treatment of UICC-stage -III / IV colon cancer with fluorouracil, leucovorin and oxaliplatin is widely accepted as current standard of treatment after R0-resection. However, as patients.. survival is increasing, long-term side effects of chemotherapeutic agents such as second cancer development are becoming increasingly important. PATIENTS: We therefore investigated a total of 2 856 Patients with UICC-stage III / IV colon cancer, 223 of whom (7.8%) had developed a subsequent second cancer. RESULTS: Median follow-up was 73.2 months (range 209.9 months, 95%-CI 69.8-76.9). Most frequent second cancers were prostate cancer (18.4%), colon cancer (16.1%), breast cancers (8.1%), lung cancer (8.1%), rectal cancer (4.9%) and uterine cancer (4.9%). However, in comparison to non-treated patients this did not represent a significantly increased risk for subsequent second cancer in patients after treatment with additive chemotherapy. Of interest, our data suggest a significantly decreased second cancer rate in patients treated with FOLFOX compared to FUFOL for additive treatment. CONCLUSIONS: Second cancer development was not increased after additive chemotherapy for colon cancer, which is a novel aspect in the ongoing discussions on reduction of adjuvant treatment to 3 months or treatment of lymph node negative patients. Novelty and Impact Statement To our knowledge, this is the first population-based study analyzing second cancer development after additive chemotherapy in patients with UICC III-IV colon cancer. The results have an important impact on the surveillance and long-term follow-up of cancer patients.

Anti-Thymocyte Globulin Treatment Augments 1,25-Dihydroxyvitamin D3 Serum Levels in Patients Undergoing Hematopoietic Stem Cell Transplantation.

Application of anti-thymocyte globulin (ATG) is a widely used strategy for the prevention of graft-versus-host disease (GvHD). As vitamin D3 serum levels are also discussed to affect hematopoietic stem cell transplantation (HSCT) outcome and GvHD development, we analysed a possible interplay between ATG treatment and serum levels of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 in 4 HSCT cohorts with different vitamin D3 supplementation. ATG is significantly associated with higher serum level of 1,25-dihydroxyvitamin D3 around HSCT (day -2 to 7, peri-transplant), however only in patients with adequate levels of its precursor 25-hydroxyvitamin D3. ATG exposure had no impact on overall survival in patients supplemented with high dose vitamin D3, but was associated with higher risk of one-year treatment-related mortality (log rank test p=0.041) in patients with no/low vitamin D3 supplementation. However, the difference failed to reach significance applying a Cox-model regression without and with adjustment for baseline risk factors (unadjusted P=0,058, adjusted p=0,139). To shed some light on underlying mechanisms, we investigated the impact of ATG on 1,25-Dihydroxyvitamin D3 production by human dendritic cells (DCs) in vitro. ATG increased gene expression of CYP27B1, the enzyme responsible for the conversion of 25-hydroxyvitamin D3 into 1,25-dihydroxyvitamin D3, which was accompanied by higher 1,25-dihydroxyvitamin D3 levels in ATG-treated DC culture supernatants. Our data demonstrate a cooperative effect of 25-hydroxyvitamin D3 and ATG in the regulation of 1,25-dihydroxyvitamin D3 production. This finding may be of importance in the context of HSCT, where early high levels of 1,25-dihydroxyvitamin D3 levels have been shown to be predictive for lower transplant related mortality and suggest that vitamin D3 supplementation may especially be important in patients receiving ATG for GvHD prophylaxis.

Cutaneous Leukemic Infiltrates Successfully Treated With Biomodulatory Therapy in a Rare Case of Therapy-Related High Risk MDS/AML.

Cutaneous manifestations in hematologic malignancies, especially in leukemia, are not common and may be very variable. Here we report a very unusual case of a patient (female, 70 years old) who was admitted to the hospital in 2016 because of skin lesions on the face, the trunk of the body and the extremities. She had a history of breast cancer in the year 2004 (pT1b, pN0, cM0, L0, V0, R0) which had been resected and treated with adjuvant radiation and chemotherapy (cyclophosphamide, methotrexate, 5-fluorouracile) as well as psoriasis treated with methotrexate and cyclosporine. Because of mild cytopenia a bone marrow aspirate/biopsy was performed showing myelodysplastic syndrome (MDS) with multilineage dysplasia. Cytogenetic review revealed a complex aberrant karyotype denoting adverse outcome. Simultaneously, a skin biopsy could confirm leukemic skin infiltration. Consequently, a therapy with azacitidine was started. After the first cycle the patient developed severe pancytopenia with a percentage of 13% peripheral blasts (previously 0-2%) as well as fever without evidence for infection which was interpreted as progressive disease. Therefore, the therapeutic regimen was changed to a biomodulatory therapy consisting of low-dose azacitidine 75 mg/day (given sc d1-7 of 28), pioglitazone 45 mg/day per os, and all-trans-retinoic acid (ATRA) 45 mg/m2/day per os. After cycle 1 of this combined biomodulatory therapy the patient showed hematologic recovery; besides a mild anemia (hemoglobin 11.1 g/dl) she developed a normal blood count. Moreover, the cutaneous leukemic infiltrates which had been unaffected by the azacitidine ameliorated tremendously after 2 cycles resulting in a complete remission of the skin lesions after cycle 6. In conclusion, we report a very unusual case with cutaneous infiltrates being the first clinical manifestation of hematologic disease, preceding the development of acute myeloid leukemia. While azacitidine alone was ineffective, a combined biomodulatory approach resulted in a complete remission of the cutaneous manifestation.

All-trans retinoic acid as adjunct to intensive treatment in younger adult patients with acute myeloid leukemia: results of the randomized AMLSG 07-04 study.

The aim of this clinical trial was to evaluate the impact of all-trans retinoic acid (ATRA) in combination with chemotherapy and to assess the NPM1 status as biomarker for ATRA therapy in younger adult patients (18-60 years) with acute myeloid leukemia (AML). Patients were randomized for intensive chemotherapy with or without open-label ATRA (45 mg/m2, days 6-8; 15 mg/m2, days 9-21). Two cycles of induction therapy were followed by risk-adapted consolidation with high-dose cytarabine or allogeneic hematopoietic cell transplantation. Due to the open label character of the study, analysis was performed on an intention-to-treat (ITT) and a per-protocol (PP) basis. One thousand one hundred patients were randomized (556, STANDARD; 544, ATRA) with 38 patients treated vice versa. Median follow-up for survival was 5.2 years. ITT analyses revealed no difference between ATRA and STANDARD for the total cohort and for the subset of NPM1-mutated AML with respect to event-free (EFS; p = 0.93, p = 0.17) and overall survival (OS; p = 0.24 and p = 0.32, respectively). Pre-specified PP analyses revealed better EFS in NPM1-mutated AML (p = 0.05) and better OS in the total cohort (p = 0.03). Explorative subgroup analyses on an ITT basis revealed better OS (p = 0.05) in ATRA for genetic low-risk patients according to ELN recommendations. The clinical trial is registered at clinicaltrialsregister.eu (EudraCT Number: 2004-004321-95).

Tumor-Induced Osteomalacia: an Up-to-Date Review.

Tumor-induced osteomalacia (TIO) is a paraneoplastic syndrome resulting in renal phosphate wasting and decreased bone mineralization. TIO is usually induced by small, slowly growing tumors of mesenchymal origin (phosphaturic mesenchymal tumor mixed connective tissue variant [PMTMCT]). Nonspecific symptoms including fatigue, bone pain, and musculoskeletal weakness make the diagnosis elusive and often lead to a delay in treatment. The prognosis of TIO is excellent following complete resection of the neoplasm, which leads to the rapid and complete reversal of all symptoms. If the tumor cannot be detected, treatment relies on supplementation with phosphate and active vitamin D compounds. Subsequent radiotherapy in case of incompletely resected tumors or definitive radiotherapy in unresectable tumors is an important treatment option to avoid recurrence or metastasis even though this occurs rarely. Due to the risk of recurrence or late metastases, long-term monitoring is required even in TIO patients diagnosed with a benign tumor.

Combining dasatinib with dexamethasone long-term leads to maintenance of antiviral and antileukemia specific cytotoxic T cell responses in vitro.

Maintaining graft versus leukemia (GvL) and antivirus responses of cytotoxic T cells (CTLs) while suppressing graft-versus-host disease (GvHD) remains a challenge after allogeneic bone marrow transplantation. Clinical observations indicate that combining glucocorticoids with multi-tyrosine-kinase inhibitors could be a successful therapeutic approach. We and others have shown that the BCR-ABL/SRC kinase inhibitor dasatinib may enhance or suppress T cells in vitro. In this report, we evaluated combination effects of dasatinib and dexamethasone on CD3⁺ and virus-specific CD8⁺ T cells directly ex vivo and on antigen-specific leukemia-reactive and alloreactive CD8⁺ T cell clones. Functional outcomes assessed included cytokine production (IL-2, IFN-γ, TNF-α), degranulation (CD107a/b), activation (CD69 upregulation), proliferation, apoptosis and necrosis induction, and signal transduction. Overall, helper CD4⁺ T cells were more sensitive to inhibitory effects of the drug combination than cytotoxic CD8⁺ T cells and were more naive than memory T cell subsets. Of note, synergistic inhibitory effects occurred in different memory but not in naive T cell subsets. The drug combination inhibited virus-specific CD8⁺ T cell proliferation, but left cytokine production and degranulation unaltered, which may be due to the viral memory subset composition. Dasatinib rather hampered IFN-γ secretion and cytotoxic activity of human leukocyte antigen (HLA)-reactive CTLs, whereas effector functions of leukemia-reactive CTLs were maintained or enhanced when applied long term. Our data suggest that dasatinib might modulate GvL- differently than GvHD-promoting CTLs and provide a rationale to explore the drug combination further to treat GvHD while preserving GvL and antiviral CTL responses.