In vitro screening of compounds from the Food and Drug Administration-approved library identifies anti-Babesia gibsoni activity of idarubicin hydrochloride and vorinostat.

Babesia gibsoni is mainly transmitted by hard ticks of the genus Rhipicephalus (R. sanguineus) and Haemaphysalis (H. longicornis), and causes canine babesiosis. Clinical manifestations of B. gibsoni infection include fever, hemoglobinemia, hemoglobinuria, and progressive anemia. Traditional antibabesial therapy, such as imidocarb dipropionate or diminazene aceturate, can only alleviate severe clinical manifestations and cannot eliminate parasites in the host. Food and Drug Administration (FDA)-approved drugs are a solid starting point for researching novel therapy strategies for canine babesiosis. In this work, we screened 640 FDA-approved drugs against the growth of B. gibsoni in vitro. Among them, 13 compounds (at 10 µM) exhibited high growth inhibition (>60%), and two compounds, namely idarubicin hydrochloride (idamycin) and vorinostat, were chosen for further investigation. The half-maximal inhibitory concentration (IC50) values of idamycin and vorinostat were determined to be 0.044 ± 0.008 µM and 0.591 ± 0.107 µM, respectively. Viability results indicated that a concentration of 4 × IC50 of vorinostat prevented the regrowth of treated B. gibsoni, whereas parasites treated with 4 × IC50 concentration of idamycin remained viable. The B. gibsoni parasites treated with vorinostat exhibited degeneration within erythrocytes and merozoites, in contrast to the oval or signet-ring shape of normal B. gibsoni parasites. In conclusion, FDA-approved drugs offer a valuable platform for drug repositioning in antibabesiosis research. Particularly, vorinostat demonstrated promising inhibitory effects against B. gibsoni in vitro, and further studies on vorinostat are necessary to elucidate its mechanism as a novel treatment in infected animal models.

Chloroquine enhances the efficacy of chemotherapy drugs against acute myeloid leukemia by inactivating the autophagy pathway.

Current therapy for acute myeloid leukemia (AML) is largely hindered by the development of drug resistance of commonly used chemotherapy drugs, including cytarabine, daunorubicin, and idarubicin. In this study, we investigated the molecular mechanisms underlying the chemotherapy drug resistance and potential strategy to improve the efficacy of these drugs against AML. By analyzing data from ex vivo drug-response and multi-omics profiling public data for AML, we identified autophagy activation as a potential target in chemotherapy-resistant patients. In THP-1 and MV-4-11 cell lines, knockdown of autophagy-regulated genes ATG5 or MAP1LC3B significantly enhanced AML cell sensitivity to the chemotherapy drugs cytarabine, daunorubicin, and idarubicin. In silico screening, we found that chloroquine phosphate mimicked autophagy inactivation. We showed that chloroquine phosphate dose-dependently down-regulated the autophagy pathway in MV-4-11 cells. Furthermore, chloroquine phosphate exerted a synergistic antitumor effect with the chemotherapy drugs in vitro and in vivo. These results highlight autophagy activation as a drug resistance mechanism and the combination therapy of chloroquine phosphate and chemotherapy drugs can enhance anti-AML efficacy.

Idarubicin-loaded biodegradable microspheres enhance sensitivity to anti-PD1 immunotherapy in transcatheter arterial chemoembolization of hepatocellular carcinoma.

Transarterial chemoembolization (TACE) is an image-guided locoregional therapy used for the treatment of patients with primary hepatocellular carcinoma (HCC). However, conventional TACE formulations such as epirubicin-lipiodol emulsion are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in the target tumor. To overcome these limitations, we used biodegradable Idarubicin loaded microspheres (BILMs), which were prepared from gelatin and carrageenan and could be loaded with Idarubicin (IDA-MS). The morphology and the ability to load and release IDA of BILMs were characterized in vitro. We evaluated tumor changes and side effects after TACE treatment with IDA-MS in VX2 rabbit and C57BL/6 mice HCC models. In addition, the effect of IDA-MS on the tumor immune microenvironment of HCC tumors was elucidated via mass spectrometry and immunohistochemistry. Result showed that IDA-MS was developed as a new TACE formulation to overcome the poor delivery of drugs due to rapid elimination of the anticancer drug into the systemic circulation. We demonstrated in rabbits and mice HCC models that TACE with IDA-MS resulted in significant tumor shrinkage and no more severe adverse events than those observed in the IDA group. TACE with IDA-MS could also significantly enhance the sensitivity of anti-PD1 immunotherapy, improve the expression of CD8+ T cells, and activate the tumor immune microenvironment in HCC. This study provides a new approach for TACE therapy and immunotherapy and illuminates the future of HCC treatment. STATEMENT OF SIGNIFICANCE: Conventional transarterial chemoembolization (TACE) formulations are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in hepatocellular carcinoma (HCC). To overcome these limitations, we used biodegradable microspheres called BILMs, which could be loaded with Idarubicin (IDA-MS). We demonstrated in rabbits and mice HCC models that TACE with IDA-MS resulted in significant tumor shrinkage and no more severe adverse events than those observed in the IDA group. TACE with IDA-MS could also significantly enhance the sensitivity of anti-PD1 immunotherapy, improve the expression of CD8+ T cells, and activate the tumor immune microenvironment in HCC. This study provides a new approach for TACE therapy and immunotherapy and illuminates the future of HCC treatment.

The Role of Mitochondrial Quality Control in Anthracycline-Induced Cardiotoxicity: From Bench to Bedside.

Cardiotoxicity is the major side effect of anthracyclines (doxorubicin, daunorubicin, epirubicin, and idarubicin), though being the most commonly used chemotherapy drugs and the mainstay of therapy in solid and hematological neoplasms. Advances in the field of cardio-oncology have expanded our understanding of the molecular mechanisms underlying anthracycline-induced cardiotoxicity (AIC). AIC has a complex pathogenesis that includes a variety of aspects such as oxidative stress, autophagy, and inflammation. Emerging evidence has strongly suggested that the loss of mitochondrial quality control (MQC) plays an important role in the progression of AIC. Mitochondria are vital organelles in the cardiomyocytes that serve as the key regulators of reactive oxygen species (ROS) production, energy metabolism, cell death, and calcium buffering. However, as mitochondria are susceptible to damage, the MQC system, including mitochondrial dynamics (fusion/fission), mitophagy, mitochondrial biogenesis, and mitochondrial protein quality control, appears to be crucial in maintaining mitochondrial homeostasis. In this review, we summarize current evidence on the role of MQC in the pathogenesis of AIC and highlight the therapeutic potential of restoring the cardiomyocyte MQC system in the prevention and intervention of AIC.

PARP-1 inhibitors enhance the chemosensitivity of leukemia cells by attenuating NF-кB pathway activity and DNA damage response induced by Idarubicin

Idarubicin (IDA), an anthracycline antineoplastic drug, is commonly used in the treatment of acute myeloid leukemia (AML) with reasonable response rates and clinical benefits. However, some patients still relapse, or do not respond, and suffer high fatality rates. Recent studies have shown that overexpression of PARP-1 may represent an important risk factor in AML patients. The aim of the present study was to determine the underlying molecular mechanisms by which the PARP-1 inhibitor Olaparib enhances the chemosensitivity of the leukemia cell line K562 and THP1 to IDA. Our data demonstrated that PARP-1 is upregulated in AML patients as well as in K562 and THP1 cells, and that the suppression of PARP-1 activity by Olaparib enhances the inhibitory effect of IDA. A mechanistic study revealed that Olaparib decreases the expressions of p-ATM, p-IκBα, XIAP and p65, and upregulates Bax, cleaved-Caspase-3 and γ-H2AX. Olaparib can enhance the induction of DNA damage by IDA, probably mediated by the inhibition of the ATM-related DNA damage response. Moreover, we also found that the nuclear translocation of p65 and the nuclear export of NEMO are inhibited when IDA and Olaparib are combined. Our results suggest that Olaparib attenuates the activity of the NF-κB pathway and decreases the DNA damage response induced by IDA. Therefore, we conclude that Olaparib is a potentially valuable chemosensitizer for leukemia patients.

Co-Treatments of Edible Curcumin from Turmeric Rhizomes and Chemotherapeutic Drugs on Cytotoxicity and FLT3 Protein Expression in Leukemic Stem Cells.

This study aims to enhance efficacy and reduce toxicity of the combination treatment of a drug and curcumin (Cur) on leukemic stem cell and leukemic cell lines, including KG-1a and KG-1 (FLT3+ LSCs), EoL-1 (FLT3+ LCs), and U937 (FLT3- LCs). The cytotoxicity of co-treatments of doxorubicin (Dox) or idarubicin (Ida) at concentrations of the IC10-IC80 values and each concentration of Cur at the IC20, IC30, IC40, and IC50 values (conditions 1, 2, 3, and 4) was determined by MTT assays. Dox-Cur increased cytotoxicity in leukemic cells. Dox-Cur co-treatment showed additive and synergistic effects in several conditions. The effect of this co-treatment on FLT3 expression in KG-1a, KG-1, and EoL-1 cells was examined by Western blotting. Dox-Cur decreased FLT3 protein levels and total cell numbers in all the cell lines in a dose-dependent manner. In summary, this study exhibits a novel report of Dox-Cur co-treatment in both enhancing cytotoxicity of Dox and inhibiting cell proliferation via FLT3 protein expression in leukemia stem cells and leukemic cells. This is the option of leukemia treatment with reducing side effects of chemotherapeutic drugs to leukemia patients.

Anthraquinones as Inhibitors of SOS RAS-GEF Activity.

Recent breakthroughs have reignited interest in RAS GEFs as direct therapeutic targets. To search for new inhibitors of SOS GEF activity, a repository of known/approved compounds (NIH-NACTS) and a library of new marine compounds (Biomar Microbial Technologies) were screened by means of in vitro RAS-GEF assays using purified, bacterially expressed SOS and RAS constructs. Interestingly, all inhibitors identified in our screenings (two per library) shared related chemical structures belonging to the anthraquinone family of compounds. All our anthraquinone SOS inhibitors were active against the three canonical RAS isoforms when tested in our SOS GEF assays, inhibited RAS activation in mouse embryonic fibroblasts, and were also able to inhibit the growth of different cancer cell lines harboring WT or mutant RAS genes. In contrast to the commercially available anthraquinone inhibitors, our new marine anthraquinone inhibitors did not show in vivo cardiotoxicity, thus providing a lead for future discovery of stronger, clinically useful anthraquinone SOS GEF blockers.

Externally triggered smart drug delivery system encapsulating idarubicin shows superior kinetics and enhances tumoral drug uptake and response.

Rationale: Increasing the bioavailable drug level in a tumor is the key to enhance efficacy of chemotherapy. Thermosensitive smart drug delivery systems (SDDS) in combination with local hyperthermia facilitate high local drug levels, thus improving uptake in the tumor. However, inability to rapidly and efficiently absorb the locally released drug results in reduced efficacy, as well as undesired redistribution of the drug away from the tumor to the system. Methods: Based on this paradigm we propose a novel approach in which we replaced doxorubicin (DXR), one of the classic drugs for nanocarrier-based delivery, with idarubicin (IDA), a hydrophobic anthracycline used solely in the free form for treatment hematologic cancers. We established a series of in vitro and in vivo experiments to in depth study the kinetics of SDDS-based delivery, drug release, intratumor biodistribution and subsequent cell uptake. Results: We demonstrate that IDA is taken up over 10 times more rapidly by cancer cells than DXR in vitro. Similar trend is observed in in vivo online imaging and less drug redistribution is shown for IDA, together resulting in 4-times higher whole tumor drug uptake for IDA vs. DXR. Together his yielded an improved intratumoral drug distribution for IDA-SDDS, translating into superior tumor response compared to DXR-SDDS treatment at the same dose. Thus, IDA - a drug that is not used for treatment of solid cancers - shows superior therapeutic index and better outcome when administered in externally triggered SDDS. Conclusions: We show that a shift in selection of chemotherapeutics is urgently needed, away from the classic drugs towards selection based on properties of a chemotherapeutic in context of the nanoparticle and delivery mode, to maximize the therapeutic efficacy.

Anthracycline-induced cytotoxicity in the GL261 glioma model system.

Glioblastoma (GBM) is a lethal astrocyte-derived tumor that is currently treated with a multi-modal approach of surgical resection, radiotherapy, and temozolomide-based chemotherapy. Alternatives to current therapies are urgently needed as its prognosis remains poor. Anthracyclines are a class of compounds that show great potential as GBM chemotherapeutic agents and are widely used to treat solid tumors outside the central nervous system. Here we investigate the cytotoxic effects of doxorubicin and other anthracyclines on GL261 glioma tumor cells in anticipation of novel anthracycline-based CNS therapies. Three methods were used to quantify dose-dependent effects of anthracyclines on adherent GL261 tumor cells, a murine cell-based model of GBM. MTT assays quantified anthracycline effects on cell viability, comet assays examined doxorubicin genotoxicity, and flow cytometry with Annexin V/PI staining characterized doxorubicin-induced apoptosis and necrosis. Dose-dependent reductions in GL261 cell viability were found in cells treated with doxorubicin (EC50 = 4.9 µM), epirubicin (EC50 = 5.9 µM), and idarubicin (EC50 = 4.4 µM). Comet assays showed DNA damage following doxorubicin treatments, peaking at concentrations of 1.0 µM and declining after 25 µM. Lastly, flow cytometric analysis of doxorubicin-treated cells showed dose-dependent induction of apoptosis (EC50 = 5.2 µM). Together, these results characterized the cytotoxic effects of anthracyclines on GL261 glioma cells. We found dose-dependent apoptotic induction; however at high concentrations we find that cell death is likely necrotic. Our results support the continued exploration of anthracyclines as compounds with significant potential for improved GBM treatments.

Low-Dose Triptolide Enhanced Activity of Idarubicin Against Acute Myeloid Leukemia Stem-like Cells Via Inhibiting DNA Damage Repair Response.

Leukemia stem cells (LSCs) are considered to be the root of relapse for acute myeloid leukemia (AML). Conventional chemotherapeutic drugs fail to eliminate LSCs. Therefore, new therapeutic strategies eliminating LSCs are urgently needed. Our results showed that low-dose Triptolide (TPL) enhanced the anti-AML activity of Idarubicin (IDA) in vitro against LSC-like cells (CD34 + CD38- KG1αand CD34 + CD38- kasumi-1 cells) and CD34+ primary AML cells, while sparing normal cells. Inspiringly, the combination treatment with low-dose TPL and IDA was also effective against CD34 + blasts from AML patients with FLT3-ITD mutation, which is an unfavorable risk factor for AML patients. Moreover, the combination of TPL and IDA induced a remarkable suppression of human leukemia growth in a xenograft mouse model. Mechanistically, the enhanced effect of low dose TPL on IDA against LSCs was attributed to inhibiting DNA damage repair response. Thus, our study may provide a theoretical basis to facilitate the development of a novel LSCs-targeting strategy for AML.Graphical abstract.

A novel dipeptide type inhibitor of the Wnt/ß-catenin pathway suppresses proliferation of acute myelogenous leukemia cells.

The Wnt/ß-catenin pathway is an attractive target for the treatment of acute myelogenous leukemia (AML), since aberrant activation of the Wnt/ß-catenin pathway contributes to carcinogenesis in various types of cancers including AML. Screening of an in-house compound library, constructed at Kyoto Pharmaceutical University, identified a novel compound designated "31" that was found to be an inhibitor of the Wnt/ß-catenin pathway. The compound inhibited T-cell factor (TCF) activity in a TCF firefly luciferase-reporter assay and suppressed the proliferation of several human AML cell lines in a dose-dependent manner. Compound 31 arrested the cell cycle of AML cells at the G1 stage and induced apoptosis. Decrease in protein and mRNA expression level of Wnt pathway-related molecules was confirmed by the analyses of western blotting and quantitative reverse transcription-polymerase chain reaction. In addition, compound 31 combined with idarubicin synergistically inhibited the proliferation of AML cells. In conclusion, these results strongly suggest that compound 31 has potential as a novel anti-AML agent targeting the Wnt/ß-catenin signaling pathway.

Radotinib enhances cytarabine (Ara-C)-induced acute myeloid leukemia cell death.

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease that frequently relapses after standard chemotherapy. Therefore, there is a need for the development of novel chemotherapeutic agents that could treat AML effectively. Radotinib, an oral BCR-ABL tyrosine kinase inhibitor, was developed as a drug for the treatment of chronic myeloid leukemia. Previously, we reported that radotinib exerts increased cytotoxic effects towards AML cells. However, little is known about the effects of combining radotinib with Ara-C, a conventional chemotherapeutic agent for AML, with respect to cell death in AML cells. Therefore, we investigated combination effects of radotinib and Ara-C on AML in this study. METHODS: Synergistic anti-cancer effects of radotinib and Ara-C in AML cells including HL60, HEL92.1.7, THP-1 and bone marrow cells from AML patients have been examined. Diverse cell biological assays such as cell viability assay, Annexin V-positive cells, caspase-3 activity, cell cycle distribution, and related signaling pathway have been performed. RESULTS: The combination of radotinib and Ara-C was found to induce AML cell apoptosis, which involved the mitochondrial pathway. In brief, combined radotinib and Ara-C significantly induced Annexin V-positive cells, cytosolic cytochrome C, and the pro-apoptotic protein Bax in AML cells including HL60, HEL92.1.7, and THP-1. In addition, mitochondrial membrane potential and Bcl-xl protein were markedly decreased by radotinib and Ara-C. Moreover, this combination induced caspase-3 activity. Cleaved caspase-3, 7, and 9 levels were also increased by combined radotinib and Ara-C. Additionally, radotinib and Ara-C co-treatment induced G0/G1 arrest via the induction of CDKIs such as p21 and p27 and the inhibition of CDK2 and cyclin E. Thus, radotinib/Ara-C induces mitochondrial-dependent apoptosis and G0/G1 arrest via the regulation of the CDKI-CDK-cyclin cascade in AML cells. In addition, our results showed that combined treatment with radotinib and Ara-C inhibits AML cell growth, including tumor volumes and weights in vivo. Also, the combination of radotinib and Ara-C can sensitize cells to chemotherapeutic agents such as daunorubicin or idarubicin in AML cells. CONCLUSIONS: Therefore, our results can be concluded that radotinib in combination with Ara-C possesses a strong anti-AML activity.

Structure-based drug repurposing to inhibit the DNA gyrase of Mycobacterium tuberculosis.

Drug repurposing is an alternative avenue for identifying new drugs to treat tuberculosis (TB). Despite the broad-range of anti-tubercular drugs, the emergence of multi-drug-resistant and extensively drug-resistant strains of Mycobacterium tuberculosis (Mtb) H37Rv, as well as the significant death toll globally, necessitates the development of new and effective drugs to treat TB. In this study, we have employed a drug repurposing approach to address this drug resistance problem by screening the drugbank database to identify novel inhibitors of the Mtb target enzyme, DNA gyrase. The compounds were screened against the ATPase domain of the gyrase B subunit (MtbGyrB47), and the docking results showed that echinacoside, doxorubicin, epirubicin, and idarubicin possess high binding affinities against MtbGyrB47. Comprehensive assessment using fluorescence spectroscopy, surface plasmon resonance spectroscopy (SPR), and circular dichroism (CD) titration studies revealed echinacoside as a potent binder of MtbGyrB47. Furthermore, ATPase, and DNA supercoiling assays exhibited an IC50 values of 2.1-4.7 µM for echinacoside, doxorubicin, epirubicin, and idarubicin. Among these compounds, the least MIC90 of 6.3 and 12 µM were observed for epirubicin and echinacoside, respectively, against Mtb. Our findings indicate that echinacoside and epirubicin targets mycobacterial DNA gyrase, inhibit its catalytic cycle, and retard mycobacterium growth. Further, these compounds exhibit potential scaffolds for optimizing novel anti-mycobacterial agents that can act on drug-resistant strains.

Idarubicin, an Anthracycline, Induces Oxidative DNA Damage in the Presence of Copper (II).

BACKGROUND/AIM: The aim of the present study was to investigate whether idarubicin (IDR) induces oxidative DNA damage in the presence of copper (II). MATERIALS AND METHODS: DNA damage was evaluated by pBR322 plasmid DNA cleavage. The formation of oxidative stress markers [O2 •- and 8-hydroxy-2'-deoxyguanosine (8-OHdG)] was analysed. RESULTS: IDR induced DNA damage and O2 •- and 8-OHdG generation in the presence of copper (II). CONCLUSION: IDR induced oxidative DNA damage in the presence of copper (II). Since it has been reported that the concentration of copper in the serum of cancer patients is higher than that in healthy groups, IDR-induced oxidative DNA damage in the presence of copper (II) may play an important role in anticancer therapeutic strategies.

Insights into idarubicin antimicrobial activity against methicillin-resistant Staphylococcus aureus.

BACKGROUND: MRSA is a major concern in community settings and in health care. The emergence of biofilms and persister cells substantially increases its antimicrobial resistance. It is very urgent to develop new antimicrobials to solve this problem. OBJECTIVE: Idarubicin was profiled to assess its antimicrobial effects in vitro and in vivo, and the underlying mechanisms. METHODS: We investigated the antimicrobial effects of idarubicin against MRSA by time-kill analysis. The antibiofilm efficacy of idarubicin was assessed by crystal violet and XTT staining, followed by laser confocal microscopy observation. The mechanisms underlying the antimicrobial effects were studied by transmission electron microscopy, all-atom molecular dynamic simulations, SYTOX staining, surface plasma resonance, and DNA gyrase inhibition assay. Further, we addressed the antimicrobial efficacy in wound and subcutaneous abscess infection in vivo. RESULTS: Idarubicin kills MRSA cells by disrupting the lipid bilayers and interrupting the DNA topoisomerase IIA subunits, and idarubicin shows synergistic antimicrobial effects with fosfomycin. Through synergy with a single dose treatment fosfomycin and the addition of the cell protector amifostine, the cytotoxicity and cardiotoxicity of idarubicin were significantly reduced without affecting its antimicrobial effects. Idarubicin alone or in combination with fosfomycin exhibited considerable efficacy in a subcutaneous abscess mouse model of MRSA infection. In addition, idarubicin also showed a low probability of causing resistance and good postantibiotic effects. CONCLUSIONS: Idarubicin and its analogs have the potential to become a new class of antimicrobials for the treatment of MRSA-related infections.

Improved Outcomes of All-trans-retinoic Acid and Arsenic Trioxide Plus Idarubicin as a Frontline Treatment in Adult Patients With Acute Promyelocytic Leukemia.

INTRODUCTION: The purpose of this study was to explore the outcomes of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) plus idarubicin (IDA) as a frontline treatment in adult patients with acute promyelocytic leukemia (APL). PATIENTS AND METHODS: We analyzed the outcomes of ATRA and intravenous ATO plus IDA as a frontline induction therapy in 118 patients with APL with high-risk (HR) and standard-risk (SR) disease from January 2008 to December 2017. The medical records of 118 patients with APL (HR, n = 45; SR, n = 73) who received the frontline triple combination regimen at Henan Provincial People's Hospital and Tongji Hospital were retrospectively reviewed. Consolidation therapy comprised 6 cycles of ATO and ATRA plus IDA, and IDA was administered in 1 to 4 cycles of consolidation therapy based on the comparable clinical efficacy compared with 6 cycles and fewer side effects to myocardium without subsequent maintenance therapy. RESULTS: Of 118 patients, there were 3 (2.5%) early deaths and 115 (97.5%) hematologic complete remissions; 102 (88.7%) of 115 patients achieved molecular complete remission following induction therapy, and all patients were polymerase chain reaction-negative for promyelocytic leukemia-retinoic acid receptor alpha after the first cycle of consolidation therapy. The 5-year overall survival (OS) and event-free survival (EFS) were 93.0% ± 2.9% and 92.4% ± 3.0%, respectively. Early death, hematologic complete remissions, molecular complete remissions, and toxicities were comparable between the HR and SR groups. The cumulative incidence of relapse in the HR group was 4.7% (n = 2), and the cumulative incidence of relapse in the SR group was 0. The OS and EFS of the SR and HR groups were comparable (92.3% ± 4.5% vs. 92.8% ± 4.0%; X2 = 0.263; P = .608; 92.3% ± 4.5% vs. 91.1% ± 4.2%, X2 = 0.917; P = .338). The total dosage of IDA was approximately 181 to 258 mg, and no patient experienced cardiotoxicity. OS and EFS were not influenced by fms-related tyrosine kinase 3 internal tandem duplication mutation status (P = .405 and P = .528, respectively). CONCLUSION: The triple combination of ATRA and ATO plus IDA as both an induction and consolidation therapy for the HR and SR groups attained excellent outcomes, and this regimen was effective, safe, and easy, without maintenance therapy. The triple combination treatment might be a preferred frontline therapy for patients with APL, especially for those with HR or the APL fms-related tyrosine kinase 3 internal tandem duplication mutation.

The Role of Anthracyclines in Acute Myeloid Leukemia Consolidation.

BACKGROUND/AIM: This study was carried out to compare the efficacy and toxicity of consolidation with cytarabine only to consolidation with anthracycline combination in patients with acute myeloid leukemia (AML) achieving complete remission (CR). PATIENTS AND METHODS: This was a multicenter, retrospective, longitudinal cohort study set between January 2010 and December 2016. RESULTS: Generally, high-dose cytarabine Ied to better survival compared to anthracycline-containing consolidation therapy, as expected. However, for patients not undergoing hematopoietic stem cell transplantation (HSCT), anthracycline use was not necessarily associated with worse survival, depending on the number of consolidation cycles. Post-remission, pre-HSCT consolidation with high-dose cytarabine did not negatively affect survival compared to previous reports. For those without FMS-like tyrosine kinase 3 (FLT3) mutation, anthracycline use was associated with a worse survival, but for those with mutation, anthracycline use did not negatively affect survival. CONCLUSION: For patients who are ineligible for HSCT, selective use of anthracycline consolidation can be a viable option, while for patients with the intention of HSCT, post-remission high-dose cytarabine is a reasonable option in the absence of available donors.

The influence of charge and lipophilicity of daunorubicin and idarubicin on their penetration of model biological membranes - Langmuir monolayer and electrochemical studies.

The interactions of two selected anthracyclines, daunorubicin (DNR) and idarubicin (IDA), with phospholipid monolayers used as simple models of cell membranes, were investigated. The results of Langmuir experiments together with Brewster angle microscopy showed that both drugs strongly affect cancer cell membranes composed of 1,2-dimyristoyl-sn-glycero-3-phospho-l-serine (DMPS). Electrostatic interactions allow positively charged DNR and IDA to interact with negatively charged DMPS polar heads but increased lipophilicity of IDA allows it to penetrate the layer more effectively than DNR and prevents from its expulsion at higher surface pressures. The analysis of the thermodynamical functions of hysteresis proves the presence of the enthalpically favorable interactions within the monolayer during its compression in the presence of idarubicin, which may form aggregates with DMPS molecules. The influence of the drugs was significantly less pronounced for a healthy cell model composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) due to the lack of strong electrostatic attractions. The interactions of drugs with pre-compressed phospholipid monolayers were also examined. The physical state of the monolayer and its packing determined only to some extent the penetration of anthracyclines. Since drug molecules first approach the polar region of the monolayer, the increase in surface pressure in time was more pronounced for negatively charged DMPS monolayers than for zwitterionic DMPC. Additionally, idarubicin was able to penetrate the precompressed DMPS monolayers more effectively than daunorubicin due to increased lipophilicity. This property of the drug was also responsible for IDA better penetration of hydrocarbon chains of supported DMPS monolayers compared to DNR, as shown by electrochemical studies.

PTEN/AKT signaling mediates chemoresistance in refractory acute myeloid leukemia through enhanced glycolysis.

Primary refractory acute myeloid leukemia (AML) and early recurrence of leukemic cells are among the most difficult hurdles to overcome in the treatment of AML. Moreover, uncertainties surrounding the molecular mechanism underlying refractory AML pose a challenge when it comes to developing novel therapeutic drugs. However, accumulating evidence suggests a contribution of phosphatase and tensin homolog (PTEN)/protein kinase B (AKT) signaling to the development of refractory AML. To assess PTEN/AKT signaling in AML, two types of AML cell lines were evaluated, namely control HL60 cells and KG1α cells, a refractory AML cell line that is resistant to idarubicin and cytarabine (AraC) treatment. Changes in the expression level of glycolysis­ and mitochondrial oxidative phosphorylation­related genes and proteins were evaluated by reverse transcription­quantitative polymerase chain reaction and western blot analyses, respectively. The mitochondrial oxygen consumption and extracellular acidification rates were measured using an XF24 analyzer. CCK8 assay and Annexin V/PI staining were used to analyze cell viability and cellular apoptosis, respectively. The PTEN protein was found to be depleted, whereas AKT phosphorylation levels were elevated in KG1α cells compared with HL60 cells. These changes were associated with increased expression of glucose transporter 1 and hexokinase 2, and increased lactate production. AKT inhibition decreased the proliferation of KG1α cells and decreased extracellular acidification without affecting HL60 cells. Notably, AKT inhibition increased the susceptibility of KG1α cells to chemotherapy with idarubicin and AraC. Taken together, the findings of the present study indicate that activation of AKT by PTEN deficiency sustains the refractory AML status through enhancement of glycolysis and mitochondrial respiration, effects that may be rescued by inhibiting AKT activity.

Idarubicin Stimulates Cell Cycle- and TET2-Dependent Oxidation of DNA 5-Methylcytosine in Cancer Cells.

The topoisomerase II inhibitor idarubicin (Ida) is an effective anticancer anthracycline drug and has been used for clinical therapies of multiple cancers. It is well-known that Ida and its analogues can induce DNA double strand breakage (DSB) by inhibiting topoisomer II and kill tumor cells. To date, it remains unknown whether they alter DNA epigenomes. Here, we show that Ida significantly stimulates the oxidation of a key epigenetic mark DNA 5-methyl-2'-deoxycytidine (5mC), which results in elevation of 5-hydroxymethyl-2'-deoxycytidine (5hmC) in four tested cell lines. Similarly, Ida analogues also display elevated 5hmC. DSB-causing topoisomer II inhibitor etopside fails to induce 5hmC change even at very high dose, which suggests the independence of the DSB. Moreover, the structure comparison supports that the histone eviction-associated amino sugar moiety is a characteristic of the anthracyclines required to promote the 5hmC elevation. Noteworthy, we also found that the 5mC oxidation is also cell-cycle dependent and mainly occurs during the S and G2/M phases. TET2 depletion diminishes the observed 5hmC elevation, which suggests that the Ida stimulation of 5hmC formation is mainly TET2-dependent. Deep-sequencing shows that 5hmC increases in all regions of the tested genome of T47D cells. The observation of a novel effect of Ida as well as other anthracycline compounds on epigenetic DNA modifications may help to further elucidate their biological and clinical effects.