Murine Leukemia Cells Research Articles

Synthesis, molecular docking, dynamics study and preliminary cytotoxicity study of some coumarin linked imidazothiadiazoles

A new series of coumarin-linked imidazo[2,1-b][1,3,4]thiadiazoles were synthesized and evaluated for their cytotoxicity inhuman T-lymphocyte (CEM), human cervix carcinoma (HeLa) and murine leukemia cells (L1210). Among the tested compounds, 3-[5‑bromo-2-(thiophen-2-ylmethyl)imidazo[2,1-b][1,3,4]thiadiazol-6-yl]-2H-chromen-2-one 9b exhibited cytotoxicity at 0.77 μM against CEM, 1.6 μM against L1210 and 0.38 μM against HeLa cells. Compound 6-(2-oxo-2H-chromen-3-yl)-2-(thiophen-2-ylmethyl)imidazo[2,1-b][1,3,4]thiadiazol-5-carbaldehyde 10b showed cytotoxicity at 3.5 μM against CEM and at 9.5 μM against HeLa cells. Further, molecular docking simulations performed to evaluate the possibility of these synthesized analogs as inhibitors of heat shock protein 90 (Hsp90), Pdb ID: 1UYL revealing that docking predictions are in good agreement with in-vitro results (-10.7 for 9b and -10.5 for 10b). The in-silico ADME parameters, pharmacokinetics and drug-likeness of all derivatives were examined in detail using the Swiss ADME webserver. By applying molecular dynamics simulation experiments a better stability was observed of compounds 8b, 9a, 10b and 11b.

Wychimicins E and F from a rare actinomycete of the genus Cryptosporangium.

Two new spirotetronate class compounds designated wychimicins E (1) and F (2) were isolated from the culture extract of an actinomycete Cryptosporangium sp. RD061707. Their structures were determined through extensive NMR analysis in comparison with wychimicin C. Both compounds lack one hydroxy group in the decalin moiety, and the relative configuration of the remaining hydroxy group was assigned by NMR analysis of triacetylwychimicin E (3). Compounds 1 and 2 showed potent antimicrobial activity against Kocuria rhizophila and Staphylococcus aureus. These compounds were also modestly cytotoxic against P388 murine leukemia cells.

Sporangimicins A-D, acylated maltose derivatives from a rare actinomycete of the genus Pseudosporangium.

Sporangimicins A-D (1-4), four anomeric pairs of diacyl disaccharides that represent a new metabolite class, were discovered from the culture extract of an actinomycete Pseudosporangium sp. RD061809. Compounds 1-4 caused peak separation in the HPLC chromatogram and partial duplication of the NMR resonances by anomeric interconversion of a maltose core modified at the two sugar 6-positions with an isobutanoyl and a methyl-branched long-chain dienoyl groups. A highlight of the structure elucidation was application of Ohrui-Akasaka's method to a chromatographically inseparable mixture of 3 and 4, which proved the composition ratio of 3 and 4 to be 82:18 and the R/S ratio at the anteiso-methyl bearing chiral center in 3 to be 66:34. Compounds 1-4 showed antimicrobial activity against Gram-positive bacteria and modest cytotoxicity toward P388 murine leukemia cells.

Cladoic Acid, an Anti-Trypanosoma cruzi Polyketide from Cladosporium sp. TP-F2020.

A new polyketide, cladoic acid, was isolated from a fungus of the genus Cladosporium. The structure of the highly oxygenated trans-decalin ring with an all-E triene side chain was elucidated by extensive spectroscopic analysis. The unique chair/twist-boat conformation of the trans-decalin core and the flexibility of the B-ring were demonstrated by computer-aided conformational analysis. Cladoic acid was active against Trypanosoma cruzi and inhibited the proliferation of amastigotes and epimastigotes with IC50 values of 27 and 46 μM, respectively, but it did not show any appreciable activity against P388 murine leukemia cells, bacteria, or fungi, indicating it is a potential candidate for drug development against Chagas disease.

MLL-AF9 regulates transcriptional initiation in mixed lineage leukemic cells

Mixed lineage leukemia-fusion proteins (MLL-FPs) are believed to maintain gene activation and induce MLL through aberrantly stimulating transcriptional elongation, but the underlying mechanisms are incompletely understood. Here, we show that both MLL1 and AF9, one of the major fusion partners of MLL1, mainly occupy promoters and distal intergenic regions, exhibiting chromatin occupancy patterns resembling that of RNA polymerase II in HEL, a human erythroleukemia cell line without MLL1 rearrangement. MLL1 and AF9 only coregulate over a dozen genes despite of their co-occupancy on thousands of genes. They do not interact with each other, and their chromatin occupancy is also independent of each other. Moreover, AF9 deficiency in HEL cells decreases global TBP occupancy while decreases CDK9 occupancy on a small number of genes, suggesting an accessory role of AF9 in CDK9 recruitment and a possible major role in transcriptional initiation via initiation factor recruitment. Importantly, MLL1 and MLL-AF9 occupy promoters and distal intergenic regions, exhibiting identical chromatin occupancy patterns in MLL cells, and MLL-AF9 deficiency decreased occupancy of TBP and TFIIE on major target genes of MLL-AF9 in iMA9, a murine acute myeloid leukemia cell line inducibly expressing MLL-AF9, suggesting that it can also regulate initiation. These results suggest that there is no difference between MLL1 and MLL-AF9 with respect to location and size of occupancy sites, contrary to what people have believed, and that MLL-AF9 may also regulate transcriptional initiation in addition to widely believed elongation.

Plakevulin A induces apoptosis and suppresses IL-6-induced STAT3 activation in HL60 cells

(+)-Plakevulin A (1), an oxylipin isolated from an Okinawan sponge Plakortis sp. inhibits enzymatic inhibition of DNA polymerases (pols) α and δ and exhibits cytotoxicity against murine leukemia (L1210) and human cervix carcinoma (KB) cell lines. However, the half-maximal inhibitory concentration (IC50) value for cytotoxicity significantly differed from those observed for the enzymatic inhibition of pols α and β, indicating the presence of target protein(s) other than pols. This study demonstrated cytotoxicity against human promyelocytic leukemia (HL60), human cervix epithelioid carcinoma (HeLa), mouse calvaria-derived pre-osteoblast (MC3T3-E1), and human normal lung fibroblast (MRC-5) cell lines. This compound had selectivity to cancer cells over normal ones. Among these cell lines, HL60 exhibited the highest sensitivity to (+)-plakevulin A. (+)-Plakevulin A induced DNA fragmentation and caspase-3 activation in HL60 cells, indicating its role in apoptosis induction. Additionally, hydroxysteroid 17-β dehydrogenase 4 (HSD17B4) was isolated from the HL60 lysate as one of its binding proteins through pull-down experiments using its biotinylated derivative and neutravidin-coated beads. Moreover, (+)-plakevulin A suppressed the activation of interleukin 6 (IL-6)-induced signal transducer and activator of transcription 3 (STAT3). Because the knockdown or inhibition of STAT3 induces apoptosis and HSD17B4 regulates STAT3 activation, (+)-plakevulin A may induce apoptosis in HL60 cell lines by suppressing STAT3 activation, potentially by binding to HSD17B4. The present findings provide valuable information for the mechanism of its action.

Structure revision of tricholomenyn B, an antimitotic geranylcyclohexenone rediscovered as a bitter and antibacterial substance, from a basidiomycete Tricholoma japonicum (Shiro-shimeji).

Tricholomenyn B, an antimitotic geranylcyclohexenone originally discovered from a basidiomycete Tricholoma acerbum, was isolated as a bitter and antibacterial constituent from fruiting bodies of T. japonicum. Careful comparison of NMR, MS, and other physicochemical properties of the isolated substance with the literature values revised a previously proposed macrolide structure 1 to a macrodiolide 2. Compound 2 was perceived bitter at a minimum dose of 37.5 μg, showed weak antimicrobial activity against Kocuria rhizophila and Staphylococcus aureus, and was marginally cytotoxic (IC50 2.6 µM) against P388 murine leukemia cells.

Ciliatonoids D–M, highly modified limonoids from the twigs of Toona ciliata

A new ring-intact limonoid, ciliatonoid D (1), five new 7,8-seco limonoids, ciliatonoids E–I (2–6), three new 7,8-seco-29-nor limonoids, ciliatonoids J–L (7–9), and a new 7,8:9,11-diseco limonoid, ciliatonoid M (10), together with eleven known limonoids were isolated from the twigs of Toona ciliata. Their structures were established by comprehensive analyses of spectroscopic, electronic circular dichroism, single-crystal X-ray diffraction data. Compound 6 bears an uncommon 1,30-oxygen bridge. Compound 10 represents a rare example of a structure with 9,11-seco limonoid from Meliaceae. The orientation of the 14,15-epoxy moiety in a known limonoid, toonayunnanae C (12), was revised as in a β-orientation by quantum NMR calculations with ML-J-DP4 probability analysis. Compound 9 and a known analogue, toonanoronoid C (11), were found to show modest in vitro cytotoxicity against HL-60 (human premyelocytic leukemia) and P-388 (murine leukemia) cell lines.

Proteomic and transcriptomic characterisation of FIA10, a novel murine leukemic cell line that metastasizes into the brain.

Brain metastasis leads to increased mortality and is a major site of relapse for several cancers, yet the molecular mechanisms of brain metastasis are not well understood. In this study, we established and characterized a new leukemic cell line, FIA10, that metastasizes into the central nervous system (CNS) following injection into the tail vein of syngeneic mice. Mice injected with FIA10 cells developed neurological symptoms such as loss of balance, tremor, ataxic gait and seizures, leading to death within 3 months. Histopathology coupled with PCR analysis clearly showed infiltration of leukemic FIA10 cells into the brain parenchyma of diseased mice, with little involvement of bone marrow, peripheral blood and other organs. To define pathways that contribute to CNS metastasis, global transcriptome and proteome analysis was performed on FIA10 cells and compared with that of the parental stem cell line FDCP-Mix and the related FIA18 cells, which give rise to myeloid leukemia without CNS involvement. 188 expressed genes (RNA level) and 189 proteins were upregulated (log2 ratio FIA10/FIA18 ≥ 1) and 120 mRNAs and 177 proteins were downregulated (log2 ratio FIA10/FIA18 ≤ 1) in FIA10 cells compared with FIA18 cells. Major upregulated pathways in FIA10 cells revealed by biofunctional analyses involved immune response components, adhesion molecules and enzymes implicated in extracellular matrix remodeling, opening and crossing the blood-brain barrier (BBB), molecules supporting migration within the brain parenchyma, alterations in metabolism necessary for growth within the brain microenvironment, and regulators for these functions. Downregulated RNA and protein included several tumor suppressors and DNA repair enzymes. In line with the function of FIA10 cells to specifically infiltrate the brain, FIA10 cells have acquired a phenotype that permits crossing the BBB and adapting to the brain microenvironment thereby escaping immune surveillance. These data and our model system FIA10 will be valuable resources to study the occurrence of brain metastases and may help in the development of potential therapies against brain invasion.

N-SALICYLOYL AMIDES AND THEIR SALTS: SYNTHESIS, BIOLOGICAL ACTIVITY AND TOXICITY

The Schotten-Baumann reaction was used to synthesize N-salicyloyl derivatives of Morpholine, Glycine and gamma-aminobutyric acid in the process between salicyloyl chloride with morpholine, glycine or gamma-aminobutyric acid with high yield. Sodium and lithium salts of the salicylamides were synthesized by the reaction of an amide with sodium ethylate or lithium hydroxide in inert solvent. The synthesized compounds were charachterized by 1H nuclear magnetic resonance spectra and elemental analysis. Purity was checked by thin layer chromatography. Quantitative analysis of metal ions was done by potentiometry. To select the most promising compounds exhibiting psychotropic (Pa > 0.8) and antiviral (Pa about 0.5) activities, computer analysis was carried out through the PASS program. In the present study, psychotropic (the open-field exploratory test, the forced swim test, the elevated plus-maze test, the passive avoidance test), analgesic (current vocalization threshold) activities and acute toxicity were evaluated. The results of psychotropic activity revealed that amides possess significant psychotropic activity and low acute toxicity. Disodium salicylurate showed a significant antiamnesic action. The results suggested a significant antidepressant activity and antiamnesic action for dilithium salicylurate and sodium salt of salycyloyl morphlide, a psychostimulant action for lithium salt of salicyloyl morphlide. Lithium gamma-(N-salycylamino)butyrate demonstrated psychostimulant and antiamnesic activities. Our present investigation demonstrated that all compounds are very safe for consumption with high LD50 value. All obtained compounds were evaluated for their antiviral activities against a large number of DNA and RNA viruses including herpes simplex viruses 1 and 2, vaccinia virus, vesicular stomatitis virus, HIV-1 and HIV-2. These compounds were evaluated against human cervix carcinoma cells (HeLa) and CEM T-lymphocytes as well as murine leukemia cells (L1210). The antiviral activity studies depicted that none of the tested compounds were active against DNA or RNA viruses.

In Vivo Modeling of Leukemia by Murine Stem Cell Transplantation.

Murine stem cell transplantation is a well-established method for the in vivo study of leukemic pathophysiology. Adoptive transfer of murine leukemic cells into lethally irradiated recipient mice leads to reconstitution of the hematopoietic system with malignant cells and eventually to leukemic progression in the recipient mice. Here, we describe the detailed protocol of the production of retroviral particles carrying the leukemic oncogene of interest as well as the isolation, retroviral transduction, and adoptive transfer of murine bone marrow cells.

Immunoproteasome function maintains oncogenic gene expression in KMT2A-complex driven leukemia

Pharmacologic targeting of chromatin-associated protein complexes has shown significant responses in KMT2A-rearranged (KMT2A-r) acute myeloid leukemia (AML) but resistance frequently develops to single agents. This points to a need for therapeutic combinations that target multiple mechanisms. To enhance our understanding of functional dependencies in KMT2A-r AML, we have used a proteomic approach to identify the catalytic immunoproteasome subunit PSMB8 as a specific vulnerability. Genetic and pharmacologic inactivation of PSMB8 results in impaired proliferation of murine and human leukemic cells while normal hematopoietic cells remain unaffected. Disruption of immunoproteasome function drives an increase in transcription factor BASP1 which in turn represses KMT2A-fusion protein target genes. Pharmacologic targeting of PSMB8 improves efficacy of Menin-inhibitors, synergistically reduces leukemia in human xenografts and shows preserved activity against Menin-inhibitor resistance mutations. This identifies and validates a cell-intrinsic mechanism whereby selective disruption of proteostasis results in altered transcription factor abundance and repression of oncogene-specific transcriptional networks. These data demonstrate that the immunoproteasome is a relevant therapeutic target in AML and that targeting the immunoproteasome in combination with Menin-inhibition could be a novel approach for treatment of KMT2A-r AML.

Inhibition of Topors Ubiquitin Ligase Augments the Efficacy of DNA Hypomethylating Agents through DNMT1 Stabilization

DNA hypomethylating agents (HMAs) are commonly used to treat myeloid malignancies including myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, their therapeutic effects are not satisfactory. We performed CRISPR-Cas9 knockout (KO) screening to identify molecular targets that enhance the efficacy of HMAs. MDS-L and MOLM-13 cells expressing Cas9 were infected with an sgRNA lentiviral library containing 12,409 sgRNAs targeting 1,383 epigenetic factors and exposed to low-dose HMAs, decitabine (DAC) or azacitidine (AZA), for 14 days. The read counts of sgRNA against TOPORS which encodes a ubiquitin/SUMO E3 ligase, were reproducibly decreased during culture specifically in the presence of HMAs in both screening. To validate the screening results, we performed competitive growth assays by co-culturing parental cells and TOPORS-KO cells using MOLM-13, MDS-L, SKK-1, and SKM-1 cells. In all cell lines, GFP-positive TOPORS-KO cells decreased over time only in the presence of HMAs. We established single-cell clones of TOPORS-KO MOLM-13 and MDS-L cells using two different sgRNAs. The cell growth of all TOPORS-KO clones was dramatically suppressed only in the presence of DAC. Mice transplanted with TOPORS-KO cells showed significantly longer survival when treated with DAC. Next, we analyzed Topors-deficient mice and no significant changes were observed in the peripheral blood or in the percentage of bone marrow (BM) hematopoietic stem and progenitor cells. Topors−/− BM cells successfully restored hematopoiesis in lethally irradiated recipient mice at levels comparable to those of WT BM cells after transplantation, suggesting that Topors is dispensable for normal hematopoiesis. Topors−/−MLL/AF9 leukemic cells showed comparable growth in the absence of DAC but significantly inferior growth in the presence of DAC compared to WT MLL/AF9 leukemic cells. We transplanted them with support BM cells into lethally irradiated recipient mice and treated with DAC. Topors−/− leukemic cells significantly decreased during treatment compared with WT leukemic cells. Enhanced cytotoxic effects of TOPORS KO combined with HMAs was closely associated with increased apoptosis. Cell cycle analysis revealed that among TOPORS-KO cells, those in the G2/M phase accumulate and those in the S phase are reduced upon DAC treatment. RNA sequencing on cells treated with DAC showed that gene sets associated with chromosome segregation and mitosis are significantly downregulated in TOPORS-KO cells. Addback experiment revealed that TOPORS RING finger domain, which mediates ubiquitination, is responsible for HMA resistance. To identify TOPORS ubiquitination substrates, we performed second CRISPR-Cas9 screening with the same library used as the first screening, using TOPORS-KO MDS-L and MOLM-13 clone cells. Both screening showed that UHRF1-DNMT1 axis is implicated in the augmented sensitivity to DAC. Consistently, DNMT1 remained more stable in TOPORS-KO cells than WT cells after DAC exposure not only in human MDS/AML cell lines but also in murine leukemic cells. HMAs incorporated into DNA trap DNMT1 and form DNA-DNMT1 crosslinks, which causes apoptosis and mitotic defects. DNMT1-DNA crosslink formation triggers the prominent SUMOylation of DNMT1 followed by ubiquitination, which promotes the resolution of crosslinks via proteasomal degradation and cell fitness. Mass analysis of ubiquitinated peptides and immunoprecipitation with Nanobody against DNMT1 demonstrated that TOPORS loss causes accumulation of SUMOylated DNMT1 due to inefficient ubiquitination, suggesting that TOPORS works as SUMO-targeted ubiquitin ligase for DNMT1. In patient samples treated with AZA (n=23), treatment resistance significantly correlated with TOPORS expression levels. Furthermore, an ubiquitination inhibitor TAK-243 as well as a SUMOylation inhibitor TAK-981 showed synergistic effect with HMAs through DNMT1 stabilization. These results suggested that they are likely to be promising therapeutic agents in clinical practice. Our findings unveil a novel mechanism of resistance to HMAs and provide an attractive therapeutic strategy for myeloid malignancies that interferes with resolution of DNA-DNMT1 crosslinks by targeting DNMT1 post-translational modification.

T-Bet Overexpression Increases 4-1BB-Costimulated CAR T Cell Potency

Data from our lab and others has demonstrated that CAR T cells form a mixed Th1/Th2 population which, in contrast to canonical T cell differentiation, produce both interferon gamma (IFN-γ) and IL-4. Whereas a growing body of evidence has highlighted the importance of IFN-γ in the CAR T cell response, IL-4 can have immune-suppressive functions. IFN-γ from CD4+ CAR T cells (CAR4s), has been shown to promote cytotoxic effector functions of CD8+ CAR T cells (CAR8s), as well as bolster activation of endogenous immune cells including CD8 T cells and NK cells (Boulch et al Sci Immunol. 2021). Given the importance of IFN-γ to effective anti-tumor immune responses, we generated murine CAR T cells that target CD19 with a CD28 costimulatory domain (1928z) and compared them to CAR T cells that overexpress T-bet (T-bet-1928z) in an effort to skew CAR T cells away from IL-4 production and towards IFN-γ production. Upon stimulation of CAR T cells with the murine B-cell acute lymphoblastic leukemia (B-ALL) cell line E2A-PBX, fewer T-bet-1928z CAR4s produced IL-4 compared to 1928z CAR4s. This suggests T-bet overexpression is a viable strategy to reduce Th2-like programming of effector functions in CAR4s. To determine the impact of T-bet overexpression on early CAR T cell efficacy in vivo, we adoptively transferred 1928z or T-bet-1928z CAR T cells into leukemia-bearing C57Bl6/J recipients and analyzed CAR T cells from the bone marrow at peak expansion of CAR T cells as well as post-contraction. Both CARs eliminated CD19+ cells from the bone marrow and mediated long-term survival. T-bet-1928z CAR4s demonstrated increased expansion at Day 4 compared to 1928z CAR4s (p=0.0412), although there was no significant difference in CAR8 numbers at this timepoint. At Day 11 post-CAR, we observed an increase in the number of T-bet-1928z CAR T cells present in the bone marrow (p<0.0001), observed in both CAR4s (p<0.0001) and CAR8s (p=0.0074). While levels of memory-associated transcription factors TCF1 and FOXO1 were the same between CARs, fewer T-bet-1928z CAR T cells expressed IL7Rα (p=0.0002) and eomesodermin (p<0.0001), which are associated with the ability of T cells to self-renew and persist in the bone marrow. To determine the impact of T-bet on the persistence and renewal capacity of 1928z CAR T cells, we adoptively transferred 1928z or T-bet-1928z CAR T cells into leukemia-bearing RAG1-knockout recipients to eliminate endogenous T cell responses to E2A-PBX. After initial leukemia clearance, we rechallenged these mice with E2A-PBX and analyzed the bone marrow after 13 days. Both CARs were able to clear the leukemia rechallenge. While CAR4s were present in the bone marrow at similar numbers, the number of CAR8s was significantly higher among mice treated with T-bet-1928z CAR T cells (p=0.0317). Our results suggest that while T-bet may enhance in vivo expansion of CAR T cells, it provides no long-term benefit or deficit to the CAR T cell response. 4-1BB co-stimulated CAR T cells are less potent than CD28-costimulated CAR T cells and have reduced effector functions. We therefore hypothesized that T-bet overexpression would improve the efficacy of 4-1BB-costimulated CAR T cells by boosting effector functions and potency. To test this, we transduced T cells with a CAR targeting CD19 that contains a 4-1BB costimulatory domain (19BBz), or a 19BBz CAR and T-bet (19BBz-T-bet). We adoptively transferred 19BBz or 19BBz-T-bet CAR T cells into leukemia-bearing C57Bl6/J recipients. Despite no difference in CAR T cell numbers in the bone marrow, we observed fewer leukemia cells in mice treated with 19BBz-T-bet CAR T cells (p=0.0318) at Day 4 post-CAR. Treatment with 19BBz-T-bet CAR T cells also significantly improved survival of leukemia-bearing mice compared to 19BBz CAR T cells (p=0.0494). Our data demonstrate T-bet overexpression improves CD28-costimulated CAR T cell expansion but does little to augment long-term responses and diminishes features associated with capacity for self-renewal. In contrast, T-bet overexpression boosts the potency of 4-1BB-costimulated CAR T cells without impairing persistence, resulting in improved overall efficacy of 4-1BB-costimulated CAR T cell therapies.

Natural Cycloartane Triterpenoids from Corypha utan Lamk. with Anticancer Activity towards P388 Cell Lines and their Predicted Interaction with FLT3.

Cancer is the second leading cause of death in the world. Leukemia is a type of cancer that accounts for 31.5% of all cancers in children under the age of 15 in industrialized countries and 15.7% in developing countries. The inhibition of FMS-like tyrosine kinase 3 (FLT3) is a suitable approach for acute myeloid leukemia (AML) therapy as it is overexpressed in AML. This study intends to explore the natural constituents from the bark of Corypha utan Lamk., and assess their cytotoxicity on murine leukemia cell lines (P388) in addition to predicting their interaction with FLT3 as a studied target by computational methods. Compounds 1 and 2 were isolated from Corypha utan Lamk using the stepwise radial chromatography method. These compounds were assessed for their cytotoxicity against Artemia salina using the BSLT and P388 cells and the MTT assay. The docking simulation was employed to predict the possible interaction between triterpenoid and FLT3. Isolation from the bark of C. utan Lamk. generated two triterpenoids, cycloartanol (1) and cycloartanone (2). Based on the in vitro and in silico studies, both compounds were found to have anticancer activity. The evaluation of cytotoxicity from this study reveals that cycloartanol (1) and cycloartanone (2) could inhibit P388 cell growth (IC50 value at 102.6 and 110.0 μg/mL, respectively). The binding energy of cycloartanone was -9.94 Kcal/mol with a Ki value of 0.051 μM, while the binding energy and Ki value of cycloartanol (1) were found to be 8.76 Kcal/mol and 0.38 μM, respectively. These compounds also demonstrate a stable interaction by forming hydrogen bonds with FLT3. Cycloartanol (1) and cycloartanone (2) exhibit potency as anticancer agents by inhibiting P388 cells in vitro and the FLT3 gene in silico.

AMPK activation induces immunogenic cell death in AML

AbstractSurvival of patients with acute myeloid leukemia (AML) can be improved by allogeneic hematopoietic stem cell transplantation (allo-HSCT) because of the antileukemic activity of T and natural killer cells from the donor. However, the use of allo-HSCT is limited by donor availability, recipient age, and potential severe side effects. Similarly, the efficacy of immunotherapies directing autologous T cells against tumor cells, including T-cell recruiting antibodies, chimeric antigen receptor T-cell therapy, and immune checkpoint inhibitors are limited in AML because of multiple mechanisms of leukemia immune escape. This has prompted a search for novel immunostimulatory approaches. Here, we show that activation of adenosine 5′-monophosphate–activated protein kinase (AMPK), a master regulator of cellular energy balance, by the small molecule GSK621 induces calreticulin (CALR) membrane exposure in murine and human AML cells. When CALR is exposed on the cell surface, it serves as a damage-associated molecular pattern that stimulates immune responses. We found that GSK621-treated murine leukemia cells promote the activation and maturation of bone marrow–derived dendritic cells. Moreover, vaccination with GSK621-treated leukemia cells had a protective effect in syngeneic immunocompetent recipients bearing transplanted AMLs. This effect was lost in recipients depleted of CD4/CD8 T cells. Together, these results demonstrate that AMPK activation by GSK621 elicits traits of immunogenic cell death and promotes a robust immune response against leukemia. Pharmacologic AMPK activation thus represents a new potential target for improving the activity of immunotherapy in AML.

Dietary γ-mangostin triggers immunogenic cell death and activates cGAS signaling in acute myeloid leukemia

Immunogenic cell death (ICD), one of cell-death types through release of damage-associated molecular patterns from dying tumor cells, activates tumor-specific immune response and elicits anti-tumor immunity by traditional radiotherapy and chemotherapy. However, whether natural products could induce ICD in leukemia is not elucidated. Here, we report dietary γ-mangostin eradicates murine primary leukemic cells and prolongs the survival of leukemic mice. As well, it restrains primary leukemic cells and CD34+ leukemic progenitor cells from leukemia patients. Strikingly, γ-mangostin attenuates leukemic cells by inducing ICD as characterized by expression of HSP90B1, ANXA1 and IL1B. Additionally, γ-mangostin accelerates cytoplasmic chromatin fragments generation, promoting DNA damage response, and enhances cGAS activation, leading to up-regulation of chemokines. Meanwhile, it induces HDAC4 degradation and acetylated histone H3 accumulation, which promotes chemokines transcription. Ultimately, CD8+ T cell is activated and recruited by γ-mangostin-induced chemokines in the microenvironment. Our study identifies γ-mangostin triggers ICD and activates cGAS signaling through DNA damage response and epigenetic modification. Therefore, dietary γ-mangostin would act as a potential agent to provoke anti-tumor immunity in the prevention and treatment of leukemia.

Nortopsentins as Leads from Marine Organisms for Anticancer and Anti-Inflammatory Agent Development.

The marine environment is an excellent source of molecules that have a wide structural diversity and a variety of biological activities. Many marine natural products (MNPs) have been established as leads for anticancer drug discovery. Most of these compounds are alkaloids, including several chemical subclasses. In this review, we focus on the bis-indolyl alkaloid Nortopsentins and their derivatives with antiproliferative properties. Nortopsentins A-C were found to exhibit in vitro cytotoxicity against the P388 murine leukaemia cell line. Their structural manipulation provided a wide range of derivatives with significant anti-tumour activity against human cell lines derived from different cancer types (bladder, colon, gastric, CNS, liver, lung, breast, melanoma, ovarian, pancreatic, prostate, pleural mesothelioma, renal, sarcoma, and uterus). In vivo assays on animal models also proved that Nortopsentins and related bis-indolyl compounds have potent anti-inflammatory activity. These remarks set the foundation for future investigations into the development of new Nortopsentin derivatives as new anticancer and anti-inflammatory agents.

Iseoic acids and bisiseoate: three new naphthohydroquinone/naphthoquinone-class metabolites from a coral-derived Streptomyces.

Two new naphthohydroquinone derivatives designated iseoic acids A (1) and B (2) and a new symmetrical glycerol bisester of naphthoquinonepropanoic acid designated bisiseoate (3) were isolated from the culture extract of a marine-derived actinomycete Streptomyces sp. DC4-5. The structures of 1-3 were determined by analyzing one- and two-dimensional NMR data and MS analytical data. The absolute configurations were determined by NOESY analysis and the phenylglycine methyl ester (PGME) method for 1 and by considering the structural similarity and biosynthesis for 2 and 3. Compound 3 exhibited modest cytotoxicity against P388 murine leukemia cells with an IC50 value of 19 μM.

Anticancer Activity Study of Modified Artocarpin Compound from Pudau Plant (Artocarpus kemando Miq.)

This research is a continuation of the successful isolation of artocarpin from the root of Artocarpus kemando Miq reported in our previous study. In the previous study, the artocarpin was characterized with UV-Vis and FTIR techniques. In this follow-up investigation, the artocarpin was subjected to a transesterification reaction using acetic anhydride and pyridine as catalysts, and the product of the reaction was specified as compound 1. The compound 1 was further characterized with different techniques to gain more complete data and then tested for anticancer activity test against P-388 murine leukemia cells. Characterizations of the compound 1 using 1H-NMR and 13C-NMR techniques suggest that the modification reaction resulted in the conversion of the -OH groups at C2' and 4' at the artocarpin molecule to -OOCH3, and based on the MS analysis, the compound was proposed to have the molecular formula of C30H32O8. Another important feature of compound 1 that should be noted is the significant improvement in stability compared to the unmodified artocarpin. Anticancer activity tests against P-388 murine leukemia cells revealed that compound 1 has an IC50of 2.35 g/mL, confirming that the compound is categorized as an active anticancer agent and suggesting that the compound has promising potential that deserves further investigations. Doi: 10.28991/ESJ-2023-07-03-05 Full Text: PDF