Antileukemic Activity Research Articles

The Anti-Leukemic Activities of Campesterol and Α-Tocopherol Against BCL-2 Target through Computational Drug Design Approaches.

Heterogeneous Acute Myeloid Leukemia (AML) causes substantial worldwide morbidity and death. AML is characterized by excessive proliferation of immature myeloid cells in the bone marrow and impaired apoptotic regulator expression. B-Cell Lymphoma 2 (BCL-2), an anti-apoptotic protein overexpressed in AML, promotes leukemic cell survival and chemoresistance. Thus, reducing BCL-2 may treat AML. Anticancer activities are found in Aloe barbadensis Miller (Aloe vera). Thus, this work used molecular modeling to assess Aloe vera bioactive chemicals as BCL-2 inhibitors. Molecular docking simulation showed that all identified Aloe vera phytocompounds have strong BCL-2 binding affinities (-6.7 to -8.7 kcal/mol). Campesterol and α-tocopherol were identified as promising compounds for BCL-2 inhibitor research based on their drug-likeness, pharmacokinetics, and toxicity profiles. The stability and conformational of the BCL-2-compound complexes showed that the compounds were stable in BCL-2's binding pocket. Campesterol and α-tocopherol are promising BCL-2 inhibitors that might become effective anti-leukemic therapies with additional in vitro and in vivo research.

GAP JUNCTION FUNCTION IS ESSENTIAL FOR SURVIVAL OF ACUTE LYMPHOBLASTIC LEUKEMIA CELLS.

Acute lymphoblastic leukemia has an intimate physical relationship with nonmalignant bone marrow stromal cells. We have recently demonstrated that stromal cells contribute to the survival of leukemia cells and that there is a bidirectional transfer of intracellular material between them. Understanding the mechanisms of stromal support of leukemia may provide insights into new therapies. To test the hypothesis that gap junctions are formed between acute lymphoblastic leukemia cells and nonmalignant stromal cells, and that gap junction function is essential for the survival of leukemia cells. We employed a well-characterized in vitro model of human bone marrow stromal cells and primary human B lymphoblastic leukemia cells and measured leukemia cell survival in coculture using flow cytometry. We measured the effects of gap junction antagonist peptides, carbenoxolone (a drug known to interfere with the gap junction function), and several leukemia chemotherapy drugs including methotrexate upon leukemia cell survival. We demonstrated that stromal cells need to be alive and metabolically active to keep leukemia cells alive. Physical contact between stromal and leukemia cells leads to an increase in gap junction proteins in leukemia cells. Gap junction inhibitory peptides impaired leukemia cell survival as did carbenoxolone, a nonpeptide inhibitor of the gap junction function. Stromal cell survival was not affected. We observed a very modest enhancement of methotrexate antileukemia activity by low-dose carbenoxolone but no significant interactions with dexamethasone, vincristine, mercaptopurine, or doxorubicin. These studies demonstrate that acute lymphoblastic cell survival is impaired by interference with the gap junction function. The development of drugs targeting gap junctions may provide a novel approach to the therapy of acute lymphoblastic leukemia.

Integrated stress response activation induced by usnic acid alleviates BCL-2 inhibitor ABT-199 resistance in acute myeloid leukemia

IntroductionABT-199 (venetoclax) is a BCL-2 suppressor with pronounced effects on acute myeloid leukemia (AML). However, its usefulness as a monotherapy or in combination with hypomethylating medicines like azacitidine is debatable due to acquired resistance. Usnic acid, a dibenzofuran extracted from lichen Usnea diffracta Vain, exhibits anticancer properties and may counteract multidrug resistance in leukemia cells. ObjectiveThis study investigated whether usnic acid at low-cytotoxicity level could enhance sensitivity of AML cells with acquired resistance to ABT-199 by targeting the integrated stress response pathways. MethodsTo investigate the combined effects on AML cells, we used a cell viability test, flow cytometry to quantify apoptosis, cell cycle analysis, and mitochondrial membrane potential measurement. RNA-seq and immunoblot were used to determine the potential mechanisms of ABT-199 + usnic acid combination. ResultsUsnic acid, at a low cytotoxicity level, successfully restored ABT-199 sensitivity in AML cell lines that had developed ABT-199 resistance and increased ABT-199′s antileukemic activity in a xenograft model. Mechanistically, the combination of usnic acid and ABT-199 cooperated to boost the expression of the integrated stress response (ISR)-associated genes ATF4, CHOP, and NOXA through the heme-regulated inhibitor kinase (HRI), while also promoting the degradation of the anti-apoptotic protein MCL-1. ISRIB, a compound that blocks the ISR, was able to reverse the growth suppression and cell death, the increase in expression of genes related with the ISR, and the inhibition of MCL-1 protein caused by combination therapy. Additionally, the downregulation of MCL-1 was linked to an increase in MCL-1 phosphorylation at serine 159 and subsequent destruction by the proteasome. ConclusionIn summary, usnic acid improves chemosensitivity to ABT-199 by triggering the integrated stress response, leading to decreased levels of MCL-1 protein, suggesting a potential treatment for AML cases resistant to Bcl-2 inhibitors.

CRISPR/Cas9 editing of NKG2A improves the efficacy of primary CD33-directed chimeric antigen receptor natural killer cells

Chimeric antigen receptor (CAR)-modified natural killer (NK) cells show antileukemic activity against acute myeloid leukemia (AML) in vivo. However, NK cell-mediated tumor killing is often impaired by the interaction between human leukocyte antigen (HLA)-E and the inhibitory receptor, NKG2A. Here, we describe a strategy that overcomes CAR-NK cell inhibition mediated by the HLA-E-NKG2A immune checkpoint. We generate CD33-specific, AML-targeted CAR-NK cells (CAR33) combined with CRISPR/Cas9-based gene disruption of the NKG2A-encoding KLRC1 gene. Using single-cell multi-omics analyses, we identified transcriptional features of activation and maturation in CAR33-KLRC1ko-NK cells, which are preserved following exposure to AML cells. Moreover, CAR33-KLRC1ko-NK cells demonstrate potent antileukemic killing activity against AML cell lines and primary blasts in vitro and in vivo. We thus conclude that NKG2A-deficient CAR-NK cells have the potential to bypass immune suppression in AML.

Fratricide-resistant CD7-CAR T cells in T-ALL.

T cell acute lymphoblastic leukemia (T-ALL) is difficult to treat when it relapses after therapy or is chemoresistant; the prognosis of patients with relapsed or refractory T-ALL is generally poor. We report a case series of 17 such patients who received autologous chimeric antigen receptor (CAR) T cells expressing an anti-CD7 CAR and an anti-CD7 protein expression blocker (PEBL), which prevented CAR T cell fratricide. Despite high leukemic burden and low CAR T cell dosing, 16 of the 17 patients attained minimal residual disease-negative complete remission within 1 month. The remaining patient had CD7- T-ALL cells before infusion, which persisted after infusion. Toxicities were mild: cytokine release syndrome grade 1 in ten patients and grade 2 in three patients; immune effector cell-associated neurotoxicity syndrome grade 1 in two patients. Eleven patients remained relapse-free (median follow-up, 15 months), including all nine patients who received an allotransplant. The first patient is in remission 55 months after infusion without further chemotherapy or transplantation; circulating CAR T cells were detectable for 2 years. T cells regenerating after lymphodepletion lacked CD7 expression, were polyclonal and responded to SARS-CoV-2 vaccination; CD7+ immune cells reemerged concomitantly with CAR T cell disappearance. In conclusion, autologous anti-CD7 PEBL-CAR T cells have powerful antileukemic activity and are potentially an effective option for the treatment of T-ALL.

Lipopolymer/siRNA complexes engineered for optimal molecular and functional response with chemotherapy in FLT3-mutated acute myeloid leukemia

Approximately 25% of newly diagnosed AML patients display an internal tandem duplication (ITD) in the fms-like tyrosine kinase 3 (FLT3) gene. Although both multi-targeted and FLT3 specific tyrosine kinase inhibitors (TKIs) are being utilized for clinical therapy, drug resistance, short remission periods, and high relapse rates are challenges that still need to be tackled. RNA interference (RNAi), mediated by short interfering RNA (siRNA), presents a mechanistically distinct therapeutic platform with the potential of personalization due to its gene sequence-driven mechanism of action. This study explored the use of a non-viral approach for delivery of FLT3 siRNA (siFLT3) in FLT3-ITD positive AML cell lines and primary cells as well as the feasibility of combining this treatment with drugs currently used in the clinic. Treatment of AML cell lines with FLT3 siRNA nanocomplexes resulted in prominent reduction in cell proliferation rates and induction of apoptosis. Quantitative analysis of relative mRNA transcript levels revealed downregulation of the FLT3 gene, which was accompanied by a similar decline in FLT3 protein levels. Moreover, an impact on leukemic stem cells was observed in a small pool of primary AML samples through significantly reduced colony numbers. An absence of a molecular response post-treatment with lipopolymer/siFLT3 complexes in peripheral blood mononuclear cells, obtained from healthy individuals, denoted a passive selectivity of the complexes towards malignant cells. The effect of combining lipopolymer/siFLT3 complexes with daunorubucin and FLT3 targeting TKI gilteritinib led to a significant augmentation of anti-leukemic activity. These findings demonstrate the promising potential of RNAi implemented with lipopolymer complexes for AML molecular therapy. The study prospectively supports the addition of RNAi therapy to current treatment modalities available to target the heterogeneity prevalent in AML. Statement of significanceWe show that a clinically validated target, the FLT3 gene, can be eradicated in leukemia cells using non-viral RNAi. We validated these lipopolymers as effective vehicles to deliver nucleic acids to leukemic cells. The potency of the lipopolymers was superior to that of the ‘gold-standard’ delivery agent, lipid nanoparticles (LNPs), which are not effective in leukemia cells at clinically relevant doses. Mechanistic studies were undertaken to probe structure-function relationships for effective biomaterial formulations. Cellular and molecular responses to siRNA treatment have been characterized in cell models, including leukemia patient-derived cells. The use of the siRNA therapy with clinically used chemotherapy was demonstrated.

Haploidentical HSCT With Fludarabine, Melphalan 75 mg/m2 and 400 cGy TBI: A Tolerable Conditioning Regimen With Low Toxicity and Good Anti-Leukemic Activity

Haploidentical HSCT With Fludarabine, Melphalan 75 mg/m2 and 400 cGy TBI: A Tolerable Conditioning Regimen With Low Toxicity and Good Anti-Leukemic Activity

CT-678 Haploidentical HSCT With Fludarabine, Melphalan 75 mg/m2 and 400 cGy TBI: A Tolerable Conditioning Regimen With Low Toxicity and Good Anti-Leukemic Activity

CT-678 Haploidentical HSCT With Fludarabine, Melphalan 75 mg/m2 and 400 cGy TBI: A Tolerable Conditioning Regimen With Low Toxicity and Good Anti-Leukemic Activity

Evaluation of ferroptosis-based anti-leukemic activities of ZnO nanoparticles synthesized by a green route against Pre-B acute lymphoblastic leukemia cells (Nalm-6 and REH)

BackgroundOur research presents an efficient and practical method for producing Zinc Oxide nanoparticles (ZnO NPs), which have anti-leukemic effects based on ferroptosis. MethodsThe black cardamom extract was employed as a capping and reducing agent for the green synthesis. The NPs have been characterized via scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. Additionally, leukemic and normal cells were exposed to ZnO NPs (25, 50, 75, 100, 150, 200, and 300 μg/mL) for 24 and 48 h. The cell vitality was then measured using the MTT test. Moreover, ferroptosis indicators were assessed via commercial testing kits, and finally, qRT-PCR and flow cytometry were used to measure gene expression and cell death. ResultsThe findings displayed that green synthesized ZnO NPs reduced the survival of leukemic cells, with IC50 values of 150.89 μg/ml for Nalm-6 and 101.31 μg/ml for REH cells after 48 h. The ZnO NPs increased ferroptosis by significantly increasing MDA, intracellular iron, ACSL4, ALOX15, and p53 mRNA expressions while significantly decreasing GSH and GPx activity levels and SLC7A11 and GPx4 mRNA expressions. On the other hand, ZnO NPs exhibited no toxicity toward normal cells. ConclusionsThe research suggests that ZnO NPs synthesized using the green approach can induce ferroptosis in leukemic cells by disrupting redox homeostasis and increasing intracellular iron levels, potentially enhancing the benefits of anti-leukemic therapies in the future.

Enhanced T cell activation and cytotoxicity against AML via targeted anti-CD99 nanoparticle treatment

CD99 is a transmembrane protein overexpressed in Acute Myeloid Leukemia (AML), presenting a potential novel therapeutic target. Our group has previously developed anti-CD99-A192 (α-CD99-A192), comprising of single chain variable fragment (scFv) and elastin-like polypeptides (ELPs), and reported promising anti-leukemic activity in AML preclinical models. Treatment with α-CD99-A192 induced apoptosis in AML cell lines and prolonged survival in AML xenograft models. Considering CD99's expression and role in T cell activation, in the current study, we propose that α-CD99-A192 plays a dual function, i.e., targeting leukemic cells and activating T cells. This manuscript reports the effects of α-CD99-A192 on T cells in the context of AML. α-CD99-A192 treatment enhances T cell proliferation and activation and increases the release of pro-inflammatory cytokines along with increased aggregation of T cells, which culminates in heightened cytotoxicity against leukemic cells. Altogether, these findings suggest α-CD99-A192 enhances T cell activation and cytotoxic potential consistent with dual mechanisms of action for α-CD99-A192.

Treosulfan-Versus Melphalan-Based Reduced Intensity Conditioning in HLA-Haploidentical Transplantation for Patients ≥ 50 Years with Advanced MDS/AML.

Relapse and regimen-related toxicities remain major challenges in achieving long-term survival, particularly among older patients with high-risk myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Previous studies have demonstrated the feasibility of treosulfan-based conditioning, noting stable engraftment and low non-relapse mortality (NRM) in patients undergoing HLA-matched allo-HSCT. However, data on treosulfan-based conditioning in the HLA-haploidentical transplantation (HaploT) setting are limited. We retrospectively compared conditioning with fludarabine-cyclophosphamide (FC)-melphalan (110 mg/m2) and FC-treosulfan (30 g/m2) prior to HaploT using post-transplantation cyclophosphamide (PTCy) in patients with high-risk MDS/AML patients ≥ 50 years, transplanted from 2009-2021 at our institution (n = 80). After balancing patient characteristics by a matched-pair analysis, we identified twenty-one matched pairs. Two-year OS and LFS were similar among the groups (OS 66% and LFS 66%, p = 0.8 and p = 0.57). However, FC-melphalan was associated with a significantly lower probability of relapse compared to FC-treosulfan (0% vs. 24%, p = 0.006), counterbalanced by a higher NRM (33% vs. 10%, p = 0.05). Time to engraftment and incidences of acute and chronic graft-versus-host disease (GvHD) did not differ significantly. In conclusion, HaploT using FC-treosulfan in combination with PTCy in patients aged ≥50 years with MDS/AML appears safe and effective, particularly in advanced disease stages. We confirm the favorable extramedullary toxicity profile, allowing for potential dose intensification to enhance antileukemic activity.

IL1RAP-specific T cell engager depletes acute myeloid leukemia stem cells

BackgroundThe interleukin-1 receptor accessory protein (IL1RAP) is highly expressed on acute myeloid leukemia (AML) bulk blasts and leukemic stem cells (LSCs), but not on normal hematopoietic stem cells (HSCs), providing an opportunity to target and eliminate the disease, while sparing normal hematopoiesis. Herein, we report the activity of BIF002, a novel anti-IL1RAP/CD3 T cell engager (TCE) in AML.MethodsAntibodies to IL1RAP were isolated from CD138+ B cells collected from the immunized mice by optoelectric positioning and single cell sequencing. Individual mouse monoclonal antibodies (mAbs) were produced and characterized, from which we generated BIF002, an anti-human IL1RAP/CD3 TCE using Fab arm exchange. Mutations in human IgG1 Fc were introduced to reduce FcγR binding. The antileukemic activity of BIF002 was characterized in vitro and in vivo using multiple cell lines and patient derived AML samples.ResultsIL1RAP was found to be highly expressed on most human AML cell lines and primary blasts, including CD34+ LSC-enriched subpopulation from patients with both de novo and relapsed/refractory (R/R) leukemia, but not on normal HSCs. In co-culture of T cells from healthy donors and IL1RAPhigh AML cell lines and primary blasts, BIF002 induced dose- and effector-to-target (E:T) ratio-dependent T cell activation and leukemic cell lysis at subnanomolar concentrations. BIF002 administered intravenously along with human T cells led to depletion of leukemic cells, and significantly prolonged survival of IL1RAPhigh MOLM13 or AML patient-derived xenografts with no off-target side effects, compared to controls. Of note, BiF002 effectively redirects T cells to eliminate LSCs, as evidenced by the absence of disease initiation in secondary recipients of bone marrow (BM) from BIF002+T cells-treated donors (median survival not reached; all survived > 200 days) compared with recipients of BM from vehicle- (median survival: 26 days; p = 0.0004) or isotype control antibody+T cells-treated donors (26 days; p = 0.0002).ConclusionsThe novel anti-IL1RAP/CD3 TCE, BIF002, eradicates LSCs and significantly prolongs survival of AML xenografts, representing a promising, novel treatment for AML.

Synthesis and Cytotoxic Activity of Friedelinyl Esters.

Commonly isolated from plants of Celastraceae family, pentacyclic triterpenoids have a broad spectrum of biological activities, such as antitumor, anti-inflammatory, antinociceptive properties, among others. Structural modifications in these triterpenoids can enhance their biological activity, as well as their selectivity, while improving their physicochemical and pharmacokinetic aspects. In this study, eight novel esters were synthesized: four derivatives of 3α-friedelinol (friedelan-3α-yl p-bromobenzoate (1a); friedelan-3α-yl naproxenate (1b); friedelan-3α-yl pent-4-ynoate (1c); friedelan-3α-yl undec-10-ynoate (1d)) and four derivatives of 3β-friedelinol (friedelan-3β-yl p-bromobenzoate (2a); friedelan-3β-yl naproxenate (2b); friedelan-3β-yl pent-4-ynoate (2c); friedelan-3β-yl undec-10-ynoate (2d)). Overall, 3α-friedelinol showed greater reactivity when compared to the β-epimer. The esters 1b-d and 2b-c were tested for antileukemic activity against THP-1 and K-562 cells but showed low cytotoxicity for both cell lines. The most active against THP-1 cells was friedelan-3β-yl naproxenate (2b, IC50=266±6 μM), and the most active against K-562 cells was friedelan-3α-yl pent-4-ynoate (1c, IC50=267±5 μM).

Synthesis, QTAIM, anticancer activity analysis of pyrrole-imidazole/benzimidazole derivatives and investigation of their reactivity properties using DFT calculations and molecular docking

As part of our ongoing investigation into pyrrole derivatives, we here present the synthesis, spectroscopic characterization, QTAIM, reactivity, anticancer activity, and comparative experimental and computational analysis of pyrrole-imidazole ((3l), (3p)) and benzimidazole derivatives ((3h), (3i), (3j), (3k), (3m), (3n), (3o)). All synthesized compounds (3h-3p) have been well characterized by spectroscopic techniques (FT-IR, 1H and 13C NMR, Mass spectrometry). The experimental 1H and 13C NMR chemical shift values of synthesized pyrrole-imidazole (3l, 3p) and benzimidazole (3h-3o) derivatives have been well corroborated with computed chemical shifts. The vibrational analysis for four derivatives of pyrrole-benzimidazole (3m), (3n), (3o), and pyrrole-imidazole (3p) has the suitability for dimer formation in solid state by intermolecular heteronuclear hydrogen bonding (N–H···O) and the interaction energy of dimers are calculated to be 10.88, 11.70, 9.89 and 10.72 kcal/mol, using DFT. After basis-set superposition error (BSSE) correction, the interaction energies of dimers were found to be 11.12, 12.11, 10.13, and 11.52 kcal/mol. Estimated intermolecular H-bond in (3m-3n) compounds were found to be -13.38, -12.86, -11.02, and -11.28 kJ/mol using QTAIM. All the synthetic pyrrole-imidazole (3l, 3p) and benzimidazole (3h-3o) derivatives exhibit strong antileukemia activity in vitro against the proliferative cell line L1210 leukemia cells. A dataset of investigated compounds was subjected for molecular modelling simulation against three distinct proteins (SYK, PI3K, and BTK), which was found to be highly implicated in the favourable interaction between the compounds and their target proteins in every instance. The synthesized pyrrole-imidazole (3l, 3p) and benzimidazole (3h-3o) derivatives shown favourable interactions with their target proteins, with high activity and binding free energy values falling between 15.22 and 13.43 and -7.4 and -9.8 kcal/mol, respectively. The structure of pyrrole-imidazole (3l, 3p) and benzimidazole (3h-3o) derivatives is thoroughly examined, and several parameters are proposed here to improve their anticancer activity.

Methylsulfonylmethane induces caspase-dependent apoptosis in acute myeloid leukemia cell lines.

Acute myeloid leukemia (AML) is a heterogeneous ailment in both biological and clinical concepts. Numerous efforts have been devoted to discover natural compounds for combating cancer, which showed great potential in cancer management. Methylsulfonylmethane (MSM), an organosulfur dietary supplement, is utilized for improving various clinical conditions, particularly osteoarthritis. MSM can exert antitumor activity in a wide range of cancers. The molecular mechanisms of action underlying antileukemic activity of MSM remain unclear. In this regard, we aimed to investigate the anticancer properties of MSM on human AML cell lines (U937 and HL60) with focus on underlying cell death mechanism. Anticancer activity of the MSM was examined employing MTT assay, Annexin V-PE/7AAD staining, caspase3/7 activity test, and real-time qPCR. Both cell lines were treated with different concentrations (50-400 mM) of MSM for 24 h. Pretreatment of the cells with a caspase inhibitor (i.e., Z-VAD-fmk) was performed for the assessment of apoptosis induction. The results of MTT assay revealed that in both cell lines, the MSM markedly reduced cell viability in comparison to the control cells. Additionally, findings of Annexin V-7AAD staining revealed that MSM induced apoptosis and activated caspase 3/7 in both cell lines markedly. Real-time quantitative PCR results also supported the induction of apoptosis in AML cells. MSM altered the expression levels of various apoptotic genes (BAX, BAD, and BIM). Overall, our results indicated that MSM could induce apoptosis in AML cell lines in a dose-dependent manner, which therefore could be utilized as anantileukemic agent.

The tandem CD33-CLL1 CAR-T as an approach to treat acute myeloid leukemia.

Acute myeloid leukemia (AML) is characterized by high heterogeneity, poor long-term survival, and a propensity for relapse. Exceptional efficacy in treating recurrent or refractory B-lymphoid malignancies has been demonstrated by Chimeric antigen receptor T cells (CAR-T cells). Given the therapeutic potential of targeting both CD33 and C-type lectin-like molecule-1 (CLL1) in AML, the development of a dual-targeting CD33-CLL1 CAR-T cells assumes significant importance. The expressions of CD33 and CLL-1 antigens in peripheral blood cells and bone marrow cells from AML patients was assessed. Subsequently, a Chimeric Antigen Receptor (CAR) incorporating a dual-specific single-chain variable fragment targeting CLL1 and CD33 (CD33-CLL1-CAR-T) was engineered. The anti-tumor efficacy and potential side effects of CD33-CLL1-CAR-T cells were comprehensively investigated in both in vitro and in vivo settings. The constructed tandem CD33-CLL1 CAR-T exhibited potent cytotoxicity against leukemia cell lines and human primary AML cells in vitro. Co-cultivation of AML blasts with CD33-CLL1-CAR-T cells resulted in effective proliferation and the secretion of substantial quantities of GM-CSF and IFN-γ. Importantly, the impact of CD33-CLL1-CAR-T cells on normal hematopoietic stem cells was minimal, ensuring safety in vivo mouse models. Notably, significant anti-leukemic activity was observed in the mouse model, with CD33-CLL1-CAR-T cells leading to tumor eradication and prolonged survival. The tandem CD33-CLL1 CAR-T cells not only efficiently eliminated AML blasts but also exhibited low cytotoxicity toward normal hematopoietic stem cells (HSCs). These findings underscore the potential clinical applicability of the tandem CD33-CLL1 CAR-T cells as an effective and safe treatment strategy for AML, representing a noteworthy advancement in the field of CAR-T cells therapy.

Gilteritinib Reduces FLT3 Expression in Acute Myeloid Leukemia Cells.

Acute myeloid leukemia (AML) is a genetically diverse and challenging malignancy, with mutations in the FLT3 gene being particularly common and deleterious. Gilteritinib, a potent FLT3 inhibitor, has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of relapsed/refractory AML with FLT3 mutations. Although gilteritinib was developed based on its inhibitory activity against FLT3 kinase, it is important to understand the precise mechanisms of its antileukemic activity in managing drug resistance and discovering biomarkers. This study was designed to elucidate the effect of gilteritinib on the FLT3 expression level. The results showed that gilteritinib induced a dose-dependent decrease in both FLT3 phosphorylation and expression. This reduction was particularly pronounced after 48 h of treatment. The decrease in FLT3 expression was found to be independent of changes in FLT3 mRNA transcription, suggesting post-transcriptional regulatory mechanisms. Further studies were performed in various AML cell lines and cells with both FLT3 wild-type and FLT3 mutant exhibited FLT3 reduction by gilteritinib treatment. In addition, other FLT3 inhibitors were evaluated for their ability to reduce FLT3 expression. Other FLT3 inhibitors, midostaurin, crenolanib, and quizartinib, also reduced FLT3 expression, consistent with the effect of gilteritinib. These findings hold great promise for optimizing gilteritinib treatment in AML patients. However, it is important to recognize that further research is warranted to gain a full understanding of these mechanisms and their clinical implications in the context of FLT3 reduction.

Herbal Medicines Genkwadaphnin as Therapeutic Agent for Cancers and Other Human Disorders: A Review of Pharmacological Activities through Scientific Evidence

Backgrounds: Daphnane-type diterpenes are an important class of phytochemicals found to be present in the family Euphorbiaceae and Thymelaeaceae. It has anti-leukaemic, antihyperglycaemic, and anti-fertility activities in medicine. Daphne genkwa is indigenous to the Yangtze River and Yellow River of China. Daphne genkwa contains significant amounts of daphnane- type diterpenes. Phytochemical analysis of Daphne genkwa led to the isolation of flavonoids, lignins, coumarins, caffeotannic acids, and genkwadaphnin. Methods: Present review highlighted the biological potential of genkwadaphnin in medicine. All the scientific data of Daphne genkwa, and genkwadaphnin were collected from Google, Google Scholar, Science Direct, Scopus, and PubMed and analyzed in the present work to know the therapeutic potential of genkwadaphnin in medicine. Detailed pharmacological activities of genkwadaphnin were analyzed in the present work through scientific data analysis of various research works. Results: Genkwadaphnin is a daphnane diterpene ester molecule mainly isolated from the Daphne genkwa, Dendrostellera lessertii, Daphne odorata, Gnidia latifolia, and Gnidia glaucus. Genkwadaphnin has been reported to exert therapeutic potential against hepatocellular carcinoma, human colon cancer, squamous cell carcinoma, and leukemia. Further, it has a significant role in innate immunity, melanogenesis, skeletal diseases, inflammatory cytokines, and natural killer cell. However, pharmacokinetics and metabolomics aspects of genkwadaphnin were also discussed in the present work. Further, more scientific data on human clinical trials is needed to ensure the safety and efficacy of genkwadaphnin in medicine. Conclusion: In the present work, a successful review had been achieved by the above-mentioned scientific data, which signified the therapeutic potential of genkwadaphnin in medicine.

Genome-wide CRISPR screening identifies critical role of phosphatase and tensin homologous (PTEN) in sensitivity of acute myeloid leukemia to chemotherapy.

Although significant progress has been made in the development of novel targeted drugs for the treatment of acute myeloid leukemia (AML) in recent years, chemotherapy still remains the mainstay of treatment and the overall survival is poor in most patients. Here, we demonstrated the antileukemia activity of a novel small molecular compound NL101, which is formed through the modification on bendamustine with a suberanilohydroxamic acid (SAHA) radical. NL101 suppresses the proliferation of myeloid malignancy cells and primary AML cells. It induces DNA damage and caspase 3-mediated apoptosis. A genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) library screen revealed that phosphatase and tensin homologous (PTEN) gene is critical for the regulation of cell survival upon NL101 treatment. The knockout or inhibition of PTEN significantly reduced NL101-induced apoptosis in AML and myelodysplastic syndrome (MDS) cells, accompanied by the activation of protein kinase B (AKT) signaling pathway. The inhibition of mammalian target of rapamycin (mTOR) by rapamycin enhanced the sensitivity of AML cells to NL101-induced cell death. These findings uncover PTEN protein expression as a major determinant of chemosensitivity to NL101 and provide a novel strategy to treat AML with the combination of NL101 and rapamycin.

Pharmaceutical inhibition of BCL6 ameliorates resistance to imatinib in chronic myeloid leukemia

The tyrosine kinase inhibitors (TKIs) have improved overall survival of CML (chronic myeloid leukemia) patients and allow them to experience normal life expectancy. However, relapse and drug resistance remain the main challenges in the clinical treatment of CML. The B-cell lymphoma 6 (BCL6) is essential to regulation of multiple function such as immune response and lymphomagenesis in lymph node germinal cells. Recent studies have shown that BCL6 is required for the maintenance of leukemia stem cells in CML, but the expression of Bcl-6 in response to Imatinib and the underlying mechanism are still unclear. Here, we found that BCL6 is expressed at high levels in primary CML bone marrow samples and CML TKI-resistance cell lines. CML cells with higher levels of BCL6 were generally sensitive to treatment with BCL6 inhibitors, BI-3812. Treatment of CML cells with BCL6 inhibitor and TKIs suggested enhanced anti-leukemia activity. In summary, our findings suggest BCL6 as a therapeutic target for the treatment of CML.