Promyelocytic Leukemia Research Articles

Acute promyelocytic leukemia can be fully treated on an outpatient basis: a single institution experience.

The objective of this study is to explore the possibility of treating APL patients fully as outpatients. A total of 21 consecutive APL patients were identified over 30 years in the Centro de Hematología y Medicina Interna de Puebla, at Clínica Ruiz, but only 17 were studied, treated as outpatients, and followed for at least 1 month; they were observed for median of 95 months, their median age was 27 years and all were treated with ATRA, prednisone, and adriamycin as outpatients. Treatment was completed on an outpatient basis in 15/17 cases. Molecular remission was achieved in 16/17 patients. The median follow-up was 95 months (IQR 19 - 360). The median OS and LFS were not reached, and the 12-month LFS was 94%. We have confirmed that APL can be treated entirely on an outpatient basis: this observation is of utmost relevance in a resource-limited setting, such as those prevailing in low- and middle-income countries.

Health-related quality of life benefits of arsenic trioxide in patients with non-high-risk acute promyelocytic leukemia are sustained over time: long-term results of the GIMEMA APL0406 trial.

Very limited evidence is available on the long-term health-related quality of life (HRQoL) of patients with acute promyelocytic leukemia (APL) treated with arsenic trioxide (ATO). We performed an extended follow-up of the APL0406 randomized controlled trial to investigate HRQoL of patients treated with either ATO or chemotherapy. A secondary objective was to describe the prevalence of clinically important problems and symptoms of these patients by type of treatment. Overall, 117 patients were included in this analysis after a median follow-up of 10 years (IQR 8-11) since diagnosis. Of these, 60 (51.3%) were treated with ATO, and 57 (48.7%) with chemotherapy. A statistically significant and clinically relevant difference, favoring patients treated with ATO, was found in 2 of the 3 main prespecified EORTC QLQ-C30 scales, that is, cognitive functioning (∆ = 7.7; 95% CI 0.5 to 14.9; p = 0.036) and fatigue (∆ = -9.4; 95% CI -17.9 to -0.8; p = 0.031). The prevalence of clinically important problems and symptoms tended to be slightly higher in patients treated with chemotherapy. These findings suggest that previously observed HRQoL advantages of ATO therapy of patients included in the APL0406 trial are sustained over the long-term period. This study was registered at ClinicalTrials.gov (NCT03096496).

Investigation of Apoptosis-mediated Cytotoxic Effects of Royal Jelly on HL-60 Cells

In recent years, the use of nontoxic natural products that can be effective on cancer cells as new agents has attracted the attention of scientists in order to reduce the negative side effects of existing cancer drugs and their toxicity to normal cells. Some in vivo and in vitro studies have shown that royal jelly (RJ) inhibits cell proliferation and induces apoptosis. In this research, we aimed to investigate the effects of RJ on proliferative and apoptotic processes in the human acute promyelocytic leukemia cell line (HL-60). The HL60 cell line was treated with different concentrations of RJ for 24, 48, and 72 hours. The half maximum inhibitory concentration (IC50) of RJ was determined using 3-(4.5 dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide test (MTT) and the proliferation activity of HL-60 cells was evaluated. Flow cytometry analysis was performed to measure apoptosis in HL-60 cells. IC50 values for RJ were calculated as 13.98, 6.45, and 2.06 mg/mL for 24, 48, and 72 hours, respectively. Flow cytometry results also showed that RJ had apoptotic effects at the concentrations found. The results showed that RJ treatment significantly induced apoptosis and reduced the proliferation of HL-60 cells. This study shows that RJ can be a complementary treatment against HL-60 acute myeloid leukemia cells due to its anticancer and antiproliferative effects.

Plasma protein binding of arsenic species in acute promyelocytic leukemia patients and their relationships with hepatic and renal function

ABSTRACT Objectives Percentage protein binding (%PB) of arsenic species in acute promyelocytic leukemia (APL) patients treated with arsenic trioxide remains unclear. It can be different depending on the status of hepatic or renal function. Methods This study obtained steady-state blood samples from normal APL patients and those with hepatic or renal impairment. %PB of inorganic arsenic (iAs), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) was determined by analyzing free and total plasma concentrations using ultrafiltration method by HPLC-HG-AFS. Results There is a linear relationship between free and total plasma concentrations for iAs (r2 = 0.952), MMAV (r2 = 0.603), and DMAV (r2 = 0.945). For patients with normal hepatic and renal function, mean %PB was as follows: iAs at 26.7 ± 14.3%, MMAV at 53.3 ± 11.9%, and DMAV at 24.7 ± 7.8%. %PB decreased in patients with renal impairment, with MMAV and DMAV showing statistically significant differences (p < 0.05 for MMAV, p < 0.01 for DMAV). No significant differences in %PB between normal and hepatic impairment group were observed. Conclusion Free arsenic species fraction can be estimated by total concentration. DMAV and iAs present low %PB, while MMAV exhibits a relatively high %PB in plasma. Level of %PB is more likely to be affected by renal function and age.

Nuclear p62 condensates stabilize the promyelocytic leukemia nuclear bodies by sequestering their ubiquitin ligase RNF4

Liquid-liquid phase separation has emerged as a crucial mechanism driving the formation of membraneless biomolecular condensates, which play important roles in numerous cellular processes. These condensates, found both in the nucleus and cytoplasm, are formed through multivalent, low-affinity interactions between various molecules. P62-containing condensates serve, among other functions, as proteolytic hubs for the ubiquitin-proteasome system. In this study, we investigated the dynamic interplay between nuclear p62 condensates and promyelocytic nuclear bodies (PML-NBs). We show that p62 condensates stabilize PML-NBs under both basal conditions and following exposure to arsenic trioxide which stimulates their degradation. We further show that this effect on the stability of PML-NBs is due to sequestration of their ubiquitin E3 ligase RNF4 in the p62 condensates with subsequent rapid degradation of the ligase. The sequestration of the ligase is made possible by association between the proline-rich domain of the PML protein and the PB1 domain of p62, which results in the formation of a PML-NB shell around the p62 condensates. Importantly, these hybrid structures do not undergo fusion and mixing of their contents which leaves unsolved the mechanism of sequestration of RNF4 in the condensates. These findings suggest an additional possible mechanism of PML-NB as a tumor suppressor which is mediated via interactions between different biomolecular condensates.

Ischemic stroke as a presenting feature of promyelocytic blast phase in chronic myeloid leukemia - an uncommon presentation: a case report and literature review in the post imatinib era.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm (MPN characterized by reciprocal translocation in the ABL1 and BCR region of chromosomes 9 and 22 respectively. Progression to the blast phase in chronic myeloid leukemia results in a poorer prognosis. It can be of either myeloid, lymphoid or a mixed lineage. Progression to the promyelocytic blast phase is very rare, and there are no evidence-based guidelines for its management. Thrombosis in CML is not well defined. Thrombosis can be seen in patients with acute promyelocytic leukemia (APL) with venous thrombosis (VTE) being more common than arterial thrombosis. Ischemic stroke as the presenting feature of blast phase progression in CML is extremely rare. We report a case of CML who presented to us with acute ischemic stroke and subsequently was diagnosed as CML transformed to the promyelocytic blast phase. She was successfully treated with dasatinib along with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO).

Beyond the Surface: Uncovering the PML::RARA Fusion in Cytogenetically Cryptic and FISH-Negative Acute Promyelocytic Leukemia- A Case Report and Review of the Literature

Abstract Introduction/Objective Chromosomal t(15;17)(q22;q21), resulting in a fusion between the PML gene on chromosome 15q22 and the RARA gene on chromosome 17q21, is the cytogenetic hallmark of acute promyelocytic leukemia (APL). Conventional karyotyping, along with fluorescence in situ hybridization (FISH), can detect the PML/RARA rearrangements in up to 98% of APL cases. Reverse transcriptase-polymerase chain reaction (RT-PCR) is often used to confirm the initial diagnosis. APL with PML::RARA fusion, which is negative with FISH and conventional karyotyping approaches but positive with RT-PCR, is extremely rare. Herein, we report a de novo APL case that was positive by RT-PCR but negative by cytogenetics and FISH studies. A comprehensive review of the literature was also performed. Methods/Case Report A 23-year-old male presented to the ED for left upper extremity weakness 2 days after post- dental cleaning. Upon admission, he developed intracranial hemorrhage, necessitating urgent decompressive hemicraniectomy. Blood smear revealed promyelocytes; flow cytometric analysis showed a CD13+, CD33+, MPO+, CD117+, CD34-, and HLA-DR- abnormal cell population. STAT interphase FISH analyses for PML/RARA fusion and RARA break-apart were negative. A diagnosis of APL was made based on abnormal promyelocytes and characteristic flow cytometry findings. ATRA was immediately administrated. However, the post-operative course was complicated by significant coagulopathy, pancytopenia, and multi-organ failure, and the patient expired 7 days later. RT-PCR returned positive for PML::RARA long fusion transcript; the conventional cytogenetics study was uninformative. The clinical, pathological, and genetic features of 31 cases of FISH/Cytogenetics-negative APL harboring cryptic rearrangements of PML-RARA, detected by RT-PCR in the literature, have been reviewed. Various detection methods were also discussed. Results (if a Case Study enter NA) N/A Conclusion Conventional cytogenetics, FISH and RT-PCR analysis are complementary studies for all clinical suspected APL cases. The clinicopathological characteristics also play critical roles in APL diagnosis when genetic confirmation of the PML::RARA fusion is unavailable.

A Rare Case of Acute Promyelocytic Leukemia with Concomitant PML-RARA Fusion and TP53 Loss/ider(17)(q10)t(15;17) Showing Complete Clinical and Molecular response: A Case Report

Abstract Introduction/Objective To report a case with rare cytogenetic abnormality: a patient with newly diagnosed acute promyelocytic leukemia (APL) with cytogenetic findings of t(15;17)(q24;q21), trisomy 8 and ider(17)(q10)t(15;17)-TP53 loss. The presence of isochromosome 17q may indicate the possibility of an unfavorable outcome. However, the case showed complete clinical and molecular response. Methods/Case Report A case of a 53-year-old female with history of ITP post-splenectomy presented with persistent hematuria, easy bruising, and worsening fatigue. She had mild microcytic anemia, moderate thrombocytopenia, 3% promyelocytes, and 14% blasts on differential CBC count. With increased PT, PTT, LDH, Uric acid and decreased fibrinogen level, APL was clinically suspected. The patient was initiated on all-trans retinoic acid (ATRA), allopurinol, and IV fluids. Bone marrow (BM) biopsy confirmed the diagnosis with unusual cytogenetic findings. The patient underwent induction and consolidation therapies (4 weeks each) with ATRA plus Arsenic Trioxide (ATO) and followed- up with a series of marrow biopsies, cytogenetic and molecular studies. Results (if a Case Study enter NA) The patient demonstrated complete clinical, histological, and molecular response. She tolerated the treatment without major side effects, showing improvement in CBC counts, coagulation profile and tumor lysis labs. Initial BM exam revealed hypercellularity with infiltrating sheets of atypical hypergranular promyelocytes (~80%) and minimal residual left trilineage hematopoiesis. Flow cytometry revealed a CD34 negative, CD117 variable abnormal promyelocyte population (~67% of total events). FISH was positive for PML/RARA translocation (15; 17) and TP53 loss. Karyotype showed 46,XX,der(15)t(15;17)(q24;q21),ider(17)(q10)t(15;17)[12]/47,idem,+8[9]. By the end of treatment, BM biopsy was normocellular with trilineage hematopoiesis and no definitive evidence of acute leukemia or increase in blasts. The Karyotype was normal. Quantitative PCR for PML-RARA was negative, indicating complete molecular remission. Conclusion In this unique case of APL with unusual cytogenetic abnormalities the literature demonstrates controversial data. The patient achieved complete clinical and molecular remission following standard treatment. This may indicate the limited prognostic significance of these additional cytogenetic abnormalities in this case.

Different prognosis according to treatment in patients with acute promyelocytic leukemia: How the outcome changed over time.

A comprehensive analysis of 220 patients diagnosed with APL between 1993 and 2022 is here reported. Overall, 214 patients (97.2%) received induction therapy. Complete response (CR) was achieved in 97.4%, 100%, 100%, and 27% of patients treated with AIDA protocol, AIDA + Ara-C, ATRA + ATO, and ATRA monotherapy, respectively. Molecular complete response (CRMRD-) was achieved in 96.8% cases, and 142 patients proceeded to maintenance therapy. Overall, the 3-year and 5-year overall survival (OS) rates were 80.8% (95% CI, 78.1-83.5) and 79.1% (95% CI, 76.4-81.8), respectively. Considering only patients who completed induction and maintenance therapy, the 5-year OS rates were 82.1% (95% CI, 77.5-86.7) for the AIDA0493 cohort, 87.5% (95% CI, 84.4-91.1) for the AIDA2000 cohort, and 100% for the APL0406 cohort (p = 0.044). Additionally, the disease-free survival (DFS) rates were 65.7% (95% CI, 60.4-70.9), 70% (95% CI, 65.8-75.2), and 95.1% (95% CI, 91.7-98.5) (p = 0.016), respectively. Among low and intermediate-risk patients, age > 70 years (p = 0.027) and relapse (p < 0.001) were significantly associated with reduced outcomes. This study contributes to the advancement of our understanding of APL treatment, underscoring the ongoing need for research to enhance outcomes and explore new therapeutic approaches and prognostic factors.

SUMO: A new perspective to decipher fibrosis.

Fibrosis is characterized by excessive extracellular matrix (ECM) deposition resulting from dysregulated wound healing and connective tissue repair mechanisms. Excessive accumulation of ECM leads to fibrous tissue formation, impairing organ function and driving the progression of various fibrotic diseases. Recently, the role of small ubiquitin-like modifiers (SUMO) in fibrotic diseases has attracted significant attention. SUMO-mediated SUMOylation, a highly conserved posttranslational modification, participates in a variety of biological processes, including nuclear-cytosolic transport, cell cycle progression, DNA damage repair, and cellular metabolism. Conversely, SUMO-specific proteases cleave the isopeptide bond of SUMO conjugates, thereby regulating the deSUMOylation process. Mounting evidence indicates that SUMOylation and deSUMOylation regulate the functions of several proteins, such as Smad3, NF-κB, and promyelocytic leukemia protein, which are implicated in fibrotic diseases like liver fibrosis, myocardial fibrosis, and pulmonary fibrosis. This review summarizes the role of SUMO in fibrosis-related pathways and explores its pathological relevance in various fibrotic diseases. All evidence suggest that the SUMO pathway is important targets for the development of treatments for fibrotic diseases.

Infection Mortality in Acute Promyelocytic Leukemia in Children

Abstract Background Acute promyelocytic leukemia (APL) is a rare entity in children. The percentage of APL patients is 5-7% of all pediatric acute myeloid leukemia cases; a higher frequency (about 20%) is reported in children of Latino/Hispanic ancestry. The introduction of trans retinoic acid has been crucial for both antileukemic efficacy in APL and for prevention of early deaths. Furthermore, the use of arsenic trioxide (ATO) demonstrated to be highly effective in achieving high cure rates with reduced toxicity. However, there is a paucity of data concerning infection related deaths in APL. The objective was to describe the percentage of infection-related-deaths in APL in children; to describe the event free survival (EFS) and describe other main complications observed. Methods We identified 30 patients, as part of the Hospital Alejandro Posadas registry from a single center. We conducted a retrospective observational descriptive analysis. The patients were treated with the GIMEMA-AIDA 2000 protocol (n=23, 76.7%) and 1-LPA pediatrico-18-GALTA/CLEHOP (n=6, 20%). One patient died before treatment was given. The patients were diagnosed between 2000 to 2022. We used frequencies for descriptive variables, Chi2 /Fisher test for categorical data and time to event techniques for survival analysis. Any cause of mortality was extracted and analyzed. Results There were 66.7% of males; and median age was 12-year (IQR 8-15). PML-Rar alfa was positive (cytogenetics) in 23 (76.7%); Negative 6 (20%) and failed in 1 patient (3.3%). 100% had positive molecular biology for PML-rarAlfa transcript. Median white cells were 3.35x 109 /l (IQR 1.675-13.25). The patients were classified as high-risk (n=10, 33.3%) and standard risk (n=20, 66.7%). Four patients showed molecular relapse, 2 had CNS and one bone marrow involvement. Three patients died (10%), 2 due to endocranial hemorrhage, 1 as a consequence of complications of a hematological relapse. No patient died due to microbiologically documented infection or febrile neutropenia. With a mean estimated survival time (median not achieved) in years of 17.7 years, (CI 95% 14.6-20.7) the event free survival was 79% (SE 0.75), with 6 events. Cumulative competitive incidence of relapse 14% (SE 0.65). Conclusion In patients with APL, we could not find infections as cause of death. The overall results of APL management were very promising. Figure 1. Event Free Survival Acute Promyelocytic Leukemia.

Evaluation of Anti-Proliferative and Apoptosis-Inducing Activities of the New Ciprofloxacin Derivative on Human Leukemia NB4 Cells

Backgrounds:: Leukemic stem cells are considered to be the main cause of treatment failure and disease recurrence due to their resistance to most common therapies. Apoptosis induction is one of the highly effective methods for treating cancer. Ciprofloxacin is among the compounds whose antitumor effects have been confirmed. Objectives: In this study, we investigated the anti-proliferative effect and induction of apoptosis by one of the derivatives of this family called 1-Cyclopropyl-6-fluoro-7-[4-(2-{[(1R,2S,5R)- 2- isopropyl-5-methylcyclohexyl]oxy}-2-oxoethyl)-piperazin-1-yl]-4-oxo-1,4-dihydroquinoline-3- carboxylic acid (ICH-CP) on NB4 cell line as an in vitro model of Acute promyelocytic leukemia (APL). NB4 cells were treated using the ICH-CP combination in various concentrations. Methods: The viability of NB4 cells was evaluated by MTT assay, and their morphology of apoptosis was examined by fluorescence microscopy. Flow cytometry and Annexin V/PI staining were used to quantify apoptosis. Finally, the expression of three genes, Bax, Bcl-2, and Survivin was inquired by real-time PCR. Results: According to the results, ICH-CP was able to destroy about 60% of NB4 cells in a dose and time-dependent manner. Light microscopy and fluorescence microscopy studies on treated cells confirmed the induction of apoptosis. Also, the real-time PCR analysis showed that ICH-CP induces apoptosis in the NB4 cell line via the down-regulation of Survivin and Bcl-2, in contrast to the up-regulation of the Bax gene. Conclusion: Based on the present data, it seems that the novel compound can be a good candidate for the treatment of acute myeloid leukemia. Furthermore, it is recommended to evaluate the qualification of ICH-CP as an adjunctive agent for other cancer cell lines.

Characteristics and Prognosis of "Acute Promyelocytic Leukemia-like" Nucleophosmin-1-Mutated Acute Myeloid Leukemia in a Retrospective Patient Cohort.

Background: AML with NPM1 mutation is the largest subcategory of AML, representing about 35% of AML cases. It is characterized by CD34 negativity, which suggests a relatively differentiated state of the bulk of leukemic blasts. Notably, a significant subset of NPM1-mutated AML cases also exhibit HLA-DR negativity, classifying them as "double-negative", and mimicking, therefore, the CD34- HLA-DR- immunophenotype of acute promyelocytic leukemia (APL). Objectives: This study focuses on the "acute promyelocytic leukemia-like" ("APL-like") subset of NPM1-mutated AML, which can be challenging to distinguish from APL at presentation, prior to confirming RARa translocations. We aim to investigate the hematologic and immunophenotypic parameters that may aid to its distinction from APL. Additionally, we explore differences in genetic profile and prognosis between "APL-like" and "non-APL-like" NPM1-mutated AML cases. Methods: We conducted a retrospective evaluation of 77 NPM1-mutated AML cases and 28 APL cases. Results: Morphological characteristics, hematologic parameters (such as DD/WBC and PT/WBC), and specific immunophenotypic markers (including SSC, CD64, and CD4) can assist in the early distinction of "APL-like" NPM1-mutated AML from APL. Regarding differences in genetic profiles and outcomes between "APL-like" and non-"APL-like" NPM1-mutated AML cases, we observed a significantly higher incidence of IDH1/2 /TET2 mutations, along with a significantly lower incidence of DNMT3A mutations in the "APL-like" subset compared to the non-"APL-like" subset. The frequency of Ras-pathway and FLT3 mutations did not differ between these last two groups, nor did their prognoses. Conclusions: Our findings contribute to a comprehensive characterization of NPM1-mutated AML, enhancing diagnostic accuracy and aiding in the detailed classification of the disease. This information may potentially guide targeted therapies or differentiation-based treatment strategies.

Retinoic acid receptor alpha expression in endometrioid heterotopias and the endometrium of patients with endometriosis

BACKGROUND: Vitamin A is a fat-soluble compound, which is a biologically inactive food form and undergoes transformation by cytosolic alcohol dehydrogenases and microsomal retinol dehydrogenases into retinaldehyde, followed by oxidation by retinaldehyde dehydrogenases 1, 2 and 3 into retinoic acid. All-trans-retinoic acid has been identified as an active metabolite of retinoic acid, indirectly participating in various processes: differentiation, proliferation and apoptosis. Based on a number of studies, the role of retinoic acid and its receptors in various diseases has been proven. For example, the destruction of the RAR-β gene by the integration of the hepatitis B virus into its loci can be a factor in the development of human hepatocellular carcinoma. Subsequently, it was described that the characteristic point of interruption of translocation t(15:17), observed in acute promyelocytic leukemia, was located at the locus encoding retinoic acid receptor-α. As a result, in patients with acute promyelocytic leukemia, complete remission of the disease could often be achieved by treatment with high doses of all-trans-retinoic acid. Existing data on the ability of retinol to influence the processes of differentiation, proliferation, and apoptosis indicate that retinol may be involved in the pathogenesis of endometriosis, but the mechanisms of its effect on the disease are subject to further study. AIM: The aim of this study was to evaluate the retinoic acid receptor alpha expression in endometrioid heterotopias and the endometrium of patients with different endometriosis stages according to the Revised American Society for Reproductive Medicine classification. MATERIALS AND METHODS: This was a prospective study to determine the retinoic acid receptor alpha expression in the endometrium and endometrioid heterotopias of patients with endometriosis (n = 28) and of the control group (n = 10). RESULTS: The retinoic acid receptor alpha expression in endometrioid heterotopias was lower compared to the eutopic endometrium of patients with endometriosis and the endometrium of patients in the control group by 3.4 and two times, respectively (p 0.001; the Kruskal – Wallis method). CONCLUSIONS: The data obtained indicate the involvement of retinol in the pathogenesis of endometriosis. Despite the relative increase in retinol level in the peripheral blood and peritoneal fluid in patients with endometriosis compared to the control group, shown in our previous studies, the reduced retinoic acid receptor alpha expression in endometrioid heterotopias does not allow for full binding of vitamin A to the receptor and is accompanied by its improper metabolism.

Esculin-Induced Apoptosis and Suppression of Leukemia Surface Markers in HL-60 and THP-1 Cells: A Potential Selective Anticancer Agent

Esculin, a natural coumarin compound primarily derived from Cortex fraxini, is known for its anti-inflammatory and antioxidant properties. Leukemia, a type of hematological cancer, is characterized by the uncontrolled proliferation of white blood cells and has high mortality rates. In this study, we aimed to investigate the potential anticancer effects of esculin (Esculetin-6-Glucoside) on leukemia cell lines, focusing on how this compound could be utilized in cancer treatment through apoptotic pathways. Our experiments used acute promyelocytic leukemia (HL-60) and acute monocytic leukemia (THP-1) cell lines. Cancer cell counting and viability analyses were conducted using the MTS assay(5-(3-carboxymethoxyphenyl)-2-(4,5-dimethylthiazol)-3-(4-sulfophenyl) tetrazolium inner salt assay). Apoptosis was assessed using FITC-labeled Annexin V and propidium iodide. Caspase-3 activation, cytochrome C release, leukemia cell surface markers, and mitochondrial membrane potential (MMP) were analyzed via flow cytometry. Our results demonstrated that esculin can induce apoptosis in leukemia cell lines. Additionally, leukemia surface markers post-treatment were statistically significantly reduced post-treatment in both cell lines. HL-60 and THP-1 cells exhibited different cellular responses in terms of MMP, Caspase-3, and Cytochrome C activities; HL-60 cells were more resistant to esculin treatment, while THP-1 cells were more sensitive. These findings suggest that esculin could become a potential agent in cancer treatment by targeting apoptotic pathways. However, more in vivo studies and preclinical modeling are needed to understand the anticancer effects of esculin fully. Evaluating its efficacy against different cancer types could further expand the therapeutic potential of this compound.

Phenolic Bisabolane Sesquiterpene Derivatives from an Arctic Marine-derived Fungus Aspergillus sydowii MNP-2

Background:: Filamentous fungi in the genus Aspergillus are well known for their important roles in production of bioactive secondary metabolites with diversely chemical structures and potential application in pharmaceutical industry. Objective:: The present study aimed to investigate the phenolic bisabolane sesquiterpene (PBS) derivatives from an Arctic marine-derived fungus Aspergillus sydowii MNP-2. Methods:: In this study, antimicrobial activities were carried out according to the broth microdilution assay, nitric oxide (NO) production in mouse macrophages (RAW264.7) and BV2 microglial cells was used to detect the inhibitory effect of compounds in inflammatory reactions, and in vitro inhibitory cell proliferation activity was determined by the cell counting kit-8 (CCK-8) assay. Results:: In this work, chemical investigation of an Arctic marine-derived strain A. sydowii MNP-2 led to the isolation of 11 PBSs (1-11) using various chromatographic methods. Their chemical structures were unambiguously determined by 1H NMR spectroscopy and mass spectrometry analyses as well as comparison with literature data. It is noteworthy that compounds 1, 7 and 11 were firstly obtained from A. sydowii. Antimicrobial assay showed that these chemicals had no potent inhibitory effect on Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values &gt; 16 μg/mL. Additionally, the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)- induced inflammation in mouse macrophages (RAW264.7) and BV2 microglial cells were all below 10% for compounds 4-6 and 8, indicating almost negligible anti-inflammatory efficacy. Among the tested compounds 4-6 and 8 for tumor-cell proliferation inhibition activities, compound 5 demonstrated the strongest inhibitory effect against human acute promyelocytic leukemia cells (HL-6) with a 44.76% inhibition rate. Conclusion:: In the present study, 11 PBS derivatives were purified and characterized from the solidand liquid-state fermentations of the Arctic marine-derived fungus A. sydowii MNP-2. Unfortunately, none of these metabolites had significant antimicrobial, anti-inflammatory, or tumor-cell proliferation inhibition activities.

Enhancing Retinoic Acid-mediated Effects Through Inhibition of CYP26A1, CYP26B1 and HGF Signaling in Neuroblastoma Cells.

Retinoic acid (RA) induces tumor cell differentiation in diseases like acute promyelocytic leukemia or high-risk neuroblastoma. However, the formation of resistant cells, which results from dysregulation of different signaling pathways, limits therapy success. The present study aimed to characterize basic regulatory processes induced by the application of RA in human neuroblastoma cells, to identify therapeutic targets independent of the often amplified oncogene MYCN. In MYCN-amplified Kelly and MYCN non-amplified SH-SY5Y cells, different assays were employed to quantify the viability and cytotoxicity, while RA-mediated expression changes were examined using genome-wide gene expression analysis followed by quantitative PCR. Enzyme-linked immunoabsorbent assays (ELISA) and western blots were used to determine the levels or activation of the examined proteins. In Kelly cells, treatment with 5 μM RA for 3 days significantly reduced the cell number due to attenuated proliferation, while SH-SY5Y cells were less responsive. An up-regulation of the RA-metabolizing enzymes CYP26A1 and CYP26B1 was observed in both cell lines, and co-treatment with the selective CYP26 inhibitor talarozole markedly decreased cell viability. When RA and ketoconazole, which inhibits CYP26 as well as RA-degrading CYP3A enzymes, were co-administered, not only cell survival was impaired in both cell lines, but also the release of hepatocyte growth factor (HGF). Accordingly, co-application of the c-Met inhibitor tepotinib and RA or ketoconazole substantially decreased cell viability. Independent of MYCN amplification, inhibitors of RA metabolism or HGF signaling might prevent the emergence of RA-resistant neuroblastoma cells when co-applied with RA.

Effects of imidazole derivatives on cellular proliferation and apoptosis in myeloid leukemia.

Acute promyelocytic leukemia (APL) is the sub-type of Acute myeloid leukemia (AML) which is described by differentiation block at promyelocytic stage and t(15; 17) translocation with All trans retinoic acid (ATRA) and arsenic trioxide (ATO) as standard treatments. Chronic myeloid leukemia (CML) translocation t (19; 22) causes a rise in granulocytes and their immature precursors in the blood. Different mutations cause resistance to first-line tyrosine kinase therapies in CML. Beside drug resistance, leukemia stem cells (LSC) are critical resources for relapse and resistance in APL and CML. The drug toxicity and resistant profile associated with LSC and current therapeutics of APL and CML necessitate the development of new therapies. Imidazoles are heterocyclic nitrogen compounds with diverse cellular actions. The purpose of this research was to assess the anti-leukemic properties of four novel imidazole derivatives including L-4, L-7, R-35, and R-NIM04. Pharmacological and biochemical approaches were used which showed that all four imidazole derivatives interfere with the NB4 cells proliferation, an APL cell line, while only L-7 exhibit anti-proliferative activity against K562 cells, a CML cell line. The anti-proliferative effect of imidazole derivatives was linked to apoptosis induction. Further real-time polymerase chain reaction (RT-PCR) analysis revealed downregulation of AXL-Receptor Tyrosine Kinase (AXL-RTK) and target genes of Wnt/beta-catenin pathway like c-Myc, Axin2 and EYA3. An additive effect was observed after combinatorial treatment of L-7 with standard drugs ATRA or Imatinib on the proliferation of NB4 and K562 cells respectively which was related to further downregulation of target genes of Wnt/beta catenin pathway. Imidazole derivatives significantly reduce proliferation of NB4 and K562 cells by inducing apoptosis, down regulating of AXL-RTK and Wnt/β-catenin target genes.

A Rare Complication in a Patient with Acute Promyelocytic Leukemia; ATRA and Posaconazole Associated Hypercalcemia

A Rare Complication in a Patient with Acute Promyelocytic Leukemia; ATRA and Posaconazole Associated Hypercalcemia

Potential of NRF2 Inhibitors-Retinoic Acid, K67, and ML-385-In Overcoming Doxorubicin Resistance in Promyelocytic Leukemia Cells.

Drug resistance is one of the major obstacles to the clinical use of doxorubicin, an extensively used chemotherapeutic drug to treat various cancers, including leukemia. Inhibition of the nuclear factor erythroid 2-related factor 2 (NRF2) seems a promising strategy to reverse chemoresistance in cancer cells. NRF2 is a transcription factor that regulates both antioxidant defense and drug detoxification mechanisms. In this study, we investigated the potential of three inhibitors of NRF2-K67, retinoic acid and ML-385-to overcome doxorubicin resistance in promyelocytic leukemia HL-60 cells. For this purpose, low-dose doxorubicin was used to establish doxorubicin-resistant HL-60/DR cells. The expression of NRF2 and its main repressor, Kelch-like ECH-associated protein 1 (KEAP1), at mRNA and protein levels was examined. HL-60/DR cells overexpressed NRF2 at mRNA and protein levels and down-regulated KEAP1 protein compared to drug-sensitive HL-60 cells. The effects of NRF2 inhibitors on doxorubicin-resistant HL-60/DR cell viability, apoptosis, and intracellular reactive oxygen species (ROS) levels were analyzed. We observed that NRF2 inhibitors significantly sensitized doxorubicin-resistant HL-60/DR cells to doxorubicin, which was associated with increased intracellular ROS levels and the expression of CAS-9, suggesting the participation of the mitochondrial-dependent apoptosis pathway. Furthermore, ML-385 inhibitor was used to study the expression of NRF2-KEAP1 pathway genes. NRF2 gene and protein expression remained unchanged; however, we noted the down-regulation of KEAP1 protein upon ML-385 treatment. Additionally, the expression of NRF2-regulated antioxidant and detoxification genes including SOD2, HMOX2, and GSS was maintained upon ML-385 treatment. In conclusion, our results demonstrated that all the studied inhibitors, namely K67, retinoic acid, and ML-385, increased the efficacy of doxorubicin in doxorubicin-resistant HL-60/DR cells, and suggested a potential strategy of combination therapy using NRF2 inhibitors and doxorubicin in overcoming doxorubicin resistance in leukemia.