Adjuvant treatment for Glioblastoma Grade 4 with Temozolomide (TMZ) inevitably fails due to therapeutic resistance, necessitating new approaches. Apoptosis induction in GB cells is inefficient, due to an excess of anti-apoptotic XPO1/Bcl-2-family proteins. We assessed TMZ, Methotrexate (MTX), and Cytarabine (Ara-C) (apoptosis inducers) combined with XPO1/Bcl-2/Mcl-1-inhibitors (apoptosis rescue) in GB cell lines and primary GB stem-like cells (GSCs). Using CellTiter-Glo® and Caspase-3 activity assays, we generated dose-response curves and analyzed the gene and protein regulation of anti-apoptotic proteins via PCR and Western blots. Optimal drug combinations were examined for their impact on the cell cycle and apoptosis induction via FACS analysis, paralleled by the assessment of potential toxicity in healthy mouse brain slices. Ara-C and MTX proved to be 150- to 10,000-fold more potent in inducing apoptosis than TMZ. In response to inhibitors Eltanexor (XPO1; E), Venetoclax (Bcl-2; V), and A1210477 (Mcl-1; A), genes encoding for the corresponding proteins were upregulated in a compensatory manner. TMZ, MTX, and Ara-C combined with E, V, and A evidenced highly lethal effects when combined. As no significant cell death induction in mouse brain slices was observed, we conclude that this drug combination is effective in vitro and expected to have low side effects in vivo.

BACKGROUND: Cytarabine (ARA-C) is an antimetabolite agent used especially in the treatment of hematologic malignancies. Infusion reactions have an important place among the side effects that may occur due to treatment. Clinical findings of infusion reactions resemble allergic reactions.
METHODS: 47-year-old male patient with a diagnosis of B-cell Acute Lymphoblastic Leukaemia developed infusion reaction during ARA-C treatment.
METHODS: There was no alternative treatment option for his existing malignant disease, we decided ARA-C desensitization.
CONCLUSIONS: We would like to describe a successful desensitization protocol in an adult patient who experienced a reaction during ARA-C infusion.

Autologous hematopoietic stem cell transplantation (Auto-HSCT) is widely used in the treatment of patients with hematological neoplasms. Since these cells circulate in small quantities in the periphery, the use of regimens that promote their mobilization is essential. In this study, we retrospectively evaluated the efficacy and safety of using intermediate doses of cytarabine (1.6 g/m²) + filgrastim (10 mcg/kg/day) in the mobilization of stem cells in 157 patients treated by the Unified Health System at the Hematology and Bone Marrow Transplant Service of the Hospital Real Português de Beneficência, in Recife, Pernambuco. The sample included patients with multiple myeloma (MM) (58.6 %), lymphomas (29.9 %), and other neoplasms (11.5 %). The target of 2.0 × 10 6 CD34+ cells/kg was achieved by 148 (94.3 %) patients, in most cases (84.1 %) in a single apheresis and the median number of cells collected was 9.5 × 10 6 CD34+ cells/kg. No episode of febrile neutropenia was observed, however, 79 patients (50.3 %) required platelet transfusion (no cases attributed to bleeding). The median engraftment time was 11 days. Given these results, we suggest that the use of intermediate doses of cytarabine, combined with filgrastim, is safe and effective in mobilizing hematopoietic stem cells (HSCs).

暂无摘要。

Neural stem cells (NSCs) are maintained in the adult mammalian brain throughout the animal\'s lifespan. NSCs in the subependymal zone infrequently divide and generate transit amplifying cells, which are destined to become olfactory bulb neurons. When transit amplifying cells are depleted, they are replenished by the quiescent NSC pool. However, the cellular basis for this recovery process remains largely unknown. In this study, we traced NSCs and their progeny after transit amplifying cells were eliminated by intraventricular infusion of cytosine β-D-arabinofuranoside. We found that although the number of neurosphere-forming NSCs decreased shortly after the treatment, they were restored to normal levels 3 weeks after the cessation of treatment. More importantly, the depletion of transit amplifying cells did not induce a significant expansion of the NSC pool by symmetric divisions. Our data suggest that the size of the NSC pool is hardly affected by brain damage due to antimitotic drug treatment.

BACKGROUND: Cytosine arabinoside (Ara-C) is a nucleoside analog prodrug utilized for immunomodulatory effects mediated by its active metabolite Ara-CTP. Optimal dosing protocols for immunomodulation in dogs have not been defined. Cytarabine ocfosfate (CO) is a lipophilic prodrug of Ara-C that can be administered PO and provides prolonged serum concentrations of Ara-C.
OBJECTIVE: Provide pharmacokinetic data for orally administered CO and determine accumulation and functional consequences of Ara-CTP within peripheral blood leukocytes.
METHODS: Three healthy female hound dogs and 1 healthy male Beagle.
METHODS: Prospective study. Dogs received 200 mg/m2 of CO PO q24h for 7 doses. Serum and cerebrospinal fluid (CSF) CO and Ara-C concentrations were measured by liquid chromatography-tandem mass spectroscopy (LC-MS/MS). Complete blood counts, flow cytometry, and leukocyte activation assays were done up to 21 days. Incorporation of Ara-CTP within leukocyte DNA was determined by LC-MS/MS.
RESULTS: Maximum serum concentration (Cmax ) for Ara-C was 456.1-724.0 ng/mL (1.88-2.98 μM) and terminal half-life was 23.3 to 29.4 hours. Cerebrospinal fluid: serum Ara-C ratios ranged from 0.54 to 1.2. Peripheral blood lymphocyte concentrations remained within the reference range, but proliferation rates poststimulation were decreased at 6 days. Incorporation of Ara-CTP was not saturated and remained >25% of peak concentration at 13 days.
CONCLUSIONS: Oral CO may produce prolonged serum Ara-C half-lives at concentrations sufficient to induce functional changes in peripheral leukocytes and is associated with prolonged retention of DNA-incorporated Ara-CTP. Application of functional and active metabolite assessment is feasible and may provide more relevant data to determine optimal dosing regimens for Ara-C-based treatments.

OBJECTIVE: The study aims to investigate the impact of m6A modulators on drug resistance and the immune microenvironment in acute myeloid leukemia (AML). The emergence of drug resistance is a significant factor that contributes to relapse and refractory AML, leading to a poor prognosis.
METHODS: The AML transcriptome data were retrieved from the TCGA database. The \"oncoPredict\" R package was utilized to assess the sensitivity of each sample to cytarabine (Ara-C) and classify them into distinct groups. Differential expression analysis was performed to identify m6A modulators differentially expressed between the two groups. Select Random Forest (RF) to build a predictive model. Model performance was evaluated using calibration curve, clinical decision curve, and clinical impact curve. The impacts of METTL3 on Ara-C sensitivity and immune microenvironment in AML were examined using GO, KEGG, CIBERSORT, and GSEA analyses.
RESULTS: Seventeen out of 26 m6A modulators exhibited differential expression between the Ara-C-sensitive and resistant groups, with a high degree of correlation. We selected the 5 genes with the highest scores in the RF model to build a reliable and accurate prediction model. METTL3 plays a vital role in m6A modification, and further analysis shows its impact on the sensitivity of AML cells to Ara-C through its interaction with 7 types of immune-infiltrating cells and autophagy.
CONCLUSIONS: This study utilizes m6A modulators to develop a prediction model for the sensitivity of AML patients to Ara-C, which can assist in treating AML drug resistance by targeting mRNA methylation.

Chemotherapeutic nucleoside analogs, such as cytarabine (Ara-C), are incorporated into genomic DNA during replication. Incorporated Ara-CMP (Ara-cytidine monophosphate) serves as a chain terminator and inhibits DNA synthesis by replicative polymerase epsilon (Polε). The proofreading exonuclease activity of Polε removes the misincorporated Ara-CMP, thereby contributing to the cellular tolerance to Ara-C. Purified Polε performs proofreading, and it is generally believed that proofreading in vivo does not need additional factors. In this study, we demonstrated that the proofreading by Polε in vivo requires CTF18, a component of the leading-strand replisome. We found that loss of CTF18 in chicken DT40 cells and human TK6 cells results in hypersensitivity to Ara-C, indicating the conserved function of CTF18 in the cellular tolerance of Ara-C. Strikingly, we found that proofreading-deficient POLE1D269A/-, CTF18-/-, and POLE1D269A/-/CTF18-/- cells showed indistinguishable phenotypes, including the extent of hypersensitivity to Ara-C and decreased replication rate with Ara-C. This observed epistatic relationship between POLE1D269A/- and CTF18-/- suggests that they are interdependent in removing mis-incorporated Ara-CMP from the 3\' end of primers. Mechanistically, we found that CTF18-/- cells have reduced levels of chromatin-bound Polε upon Ara-C treatment, suggesting that CTF18 contributes to the tethering of Polε on fork at the stalled end and thereby facilitating the removal of inserted Ara-C. Collectively, these data reveal the previously unappreciated role of CTF18 in Polε-exonuclease-mediated maintenance of the replication fork upon Ara-C incorporation.

BACKGROUND: Currently, high doses of cytarabine arabinoside (Ara-C)-based combined chemotherapy are commonly used in acute myeloid leukemia (AML) therapy, but severe adverse effects and poor suppression effects in leukemia cells limit the clinical therapeutic efficiency of Ara-C-based chemotherapy due to a lack of targeting selectivity. To improve the therapeutic effect of Ara-C in AML, here, since we confirmed that transferrin receptor 1 (TFRC) expression in AML cells was constant, we generated Ara-C@HFn by encapsulating free Ara-C into self-assembled heavy ferritin chain (HFn, the ligand of TFRC) nanocages.
RESULTS: The analysis of clinically relevant data suggested that the high expression levels of TFRC from AML cells would not decrease significantly after treatment with Ara-C. Ara-C@HFn can be efficiently internalized by leukemia cells, showing stronger cytotoxic effects in vitro and reducing the burden of leukemia in AML mice more effectively in vivo than free Ara-C. Ara-C@HFn treatment showed no acute toxicity in visceral organs of mice. Moreover, the analysis of clinically relevant data also suggested that there are several drugs (such as tamibarotene and ABT199) that would not cause significant expression down-regulation of TFRC in AML cells (after treatment).
CONCLUSIONS: The above results suggested that TFRC can be used as a constant and effective target for drug targeting delivery of AML cells. Thus Ara-C@HFn treatment can become a safe and efficient strategy for AML therapy by specifically delivering Ara-C to AML cells. Besides, the HFn nanocages are promising for improving antineoplastic effect of other AML-related therapy drugs that do not cause downregulated expression of TFRC in AML cells.

OBJECTIVE: Although acute myeloid leukemia (AML) has traditionally been considered an oncological emergency and initiation of therapy is believed to be crucial to minimizing disease-related morbidity and mortality, it has also been suggested that a certain delay in treatment has no negative consequences in terms of response, early mortality, or survival. We aimed to determine the effect of administration of sodium caseinate (SC), a salt of casein, the main milk protein, with cytarabine or with daunorubicin on survival in mice with well-established leukemia.
METHODS: To assay the time of establishment of leukemia in the bone marrow, Balb/c mice were inoculated with 2.5×10 5 WEHI-3 cells/mouse and after 3, 6 and 9 days were euthanized. Bone marrow mononuclear cells (BM-MNCs) of the femur were obtained and cultured for 120 h with or without rmIL-3 and cell proliferation was evaluated by the crystal violet technique. Then, the effect of administrating SC-cytarabine or SC-daunorubicin on survival rates of mice with well-established leukemia was assayed. Another group of Balb/c mice was inoculated with WEHI-3 cell and after 10 days mice were treated with SC-cytarabine or SC-daunorubicin for 40 days. Survival rates were recorded daily and in surviving mice, the prevalence of bone marrow proliferation after treatment was assayed by the crystal violet technique.
RESULTS: The assay on the time of establishment of leukemia shows that in 9 days leukemia cells accumulate in the bone marrow in sufficient quantities to sustain an in vitro culture in the absence of growth factors, and we, thus, used this as a criterion of well-established leukemia. When mice with a burden of leukemic cells of more than 9 days were treated with SC-cytarabine or SC-daunorubicin, this resulted in 55% survival for both treatments, and the proliferation assays showed that the bone marrow retained its normal proliferation capacity.
CONCLUSIONS: SC-cytarabine or SC-daunorubicin treatment prolonged the survival rate of Balb/c mice with a burden of well-established leukemia, and there was no negative impact on bone marrow functionality; however, SC-cytarabine or SC-daunorubicin combination options need to be sought to increase survival beyond 40 days.