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.

Downregulation of c-Myc expression confers sensitivity to CHK1 inhibitors in hematologic malignancies.

Checkpoint kinase 1 inhibitors (CHK1i) have shown impressive single-agent efficacy in treatment of certain tumors, as monotherapy or potentiators of chemotherapy in clinical trials, but the sensitive tumor types and downstream effectors to dictate the therapeutic responses to CHK1i remains unclear. In this study we first analyzed GDSC (Genomics of Drug Sensitivity in Cancer) and DepMap database and disclosed that hematologic malignancies (HMs) were relatively sensitive to CHK1i or CHK1 knockdown. This notion was confirmed by examining PY34, a new and potent in-house selective CHK1i, which exhibited potent anti-HM effect in vitro and in vivo, as single agent. We demonstrated that the downregulation of c-Myc and its signaling pathway was the common transcriptomic profiling response of sensitive HM cell lines to PY34, whereas overexpressing c-Myc could partially rescue the anticancer effect of PY34. Strikingly, we revealed the significant correlations between downregulation of c-Myc and cell sensitivity to PY34 in 17 HM cell lines and 39 patient-derived cell (PDC) samples. Thus, our results demonstrate that HMs are more sensitive to CHK1i than solid tumors, and c-Myc downregulation could represent the CHK1i efficacy in HMs.

Design, Synthesis, and In Vitro Evaluation of Benzofuro[3,2-c]Quinoline Derivatives as Potential Antileukemia Agents.

Herein, we design and synthesize an array of benzofuro[3,2-c]quinolines starting from 3-(2-methoxyphenyl)quinolin-4(1H)ones via a sequential chlorination/demethylation, intramolecular cyclization pathway. This sequential transformation was efficient, conducted under metal-free and mild reaction conditions, and yielded corresponding benzofuro[3,2-c]quinolines in high yields. In vitro biological evaluation indicated that such type of compounds showed excellent antileukemia activity and selectivity, and therefore may offer a promising hit compound for developing antileukemia compounds.

3-(7-Azaindolyl)-4-indolylmaleimides as a novel class of mutant isocitrate dehydrogenase-1 inhibitors: Design, synthesis, and biological evaluation.

A series of 3-(7-azainodyl)-4-indolylmaleimides was designed, synthesized, and evaluated for their isocitrate dehydrogenase 1 (IDH1)/R132H inhibitory activities. Many compounds such as 11a, 11c, 11e, 11g, and 11s exhibited favorable inhibitory effects on IDH1/R132H and were highly selective against the wild-type IDH1. Evaluation of the biological activities at the cellular level showed that compounds 11a, 11c, 11e, 11g, and 11s could effectively suppress the production of 2-hydroxyglutaric acid in U87MG cells expressing IDH1/R132H. Preliminary structure-activity relationship (SAR) and molecular modeling studies were discussed based on the experimental data obtained. These findings may provide new insights into the development of novel IDH1/R132H inhibitors.

Discovery of 5-trifluoromethyl-2-aminopyrimidine derivatives as potent dual inhibitors of FLT3 and CHK1.

Here, we discover an FLT3/CHK1 dual inhibitor (30) that exhibits excellent kinase potency and antiproliferative activity against MV4-11 cells. Simultaneously, 30 possesses high selectivity over c-Kit enzyme and low hERG inhibitory ability. Compound 30, meanwhile, overcomes varied resistance in BaF3 cell lines carrying FLT3-TKD and FLT3-ITD mutations. Moreover, 30 demonstrates favorable oral PK properties and kinase selectivity. These conclusions support that compound 30 may be a promising potential FLT3/CHK1 dual agent for further development.

Design, Synthesis, and Biological Evaluation of 2-Aminothiazole Derivatives as Novel Checkpoint Kinase 1 (CHK1) Inhibitors.

A series of 2-aminothiazole derivatives were designed, synthesized on the basis of bioisosterism strategy and evaluated for their CHK1 inhibitory activity. Most of them exhibited potent CHK1 inhibition, and excellent antiproliferative activity against MV-4-11 and Z-138 cell lines. Systematic structure-activity relationship (SAR) efforts led to the discovery of a promising compound 8 n, which showed potent CHK1 inhibitory activity with IC50 value of 4.25±0.10 nM, excellent antiproliferative activity against MV-4-11 and Z-138 cells with IC50 value of 42.10±5.77 nM and 24.16±6.67 nM, respectively, as well as moderate oral exposure (AUC(0-t) =1076.25 h ⋅ ng/mL) in mice. Additionally, treatment of MV-4-11 cells with compound 8 n for 2 h led to robust inhibition of CHK1 autophosphorylation on serine 296. Furthermore, kinase selectivity assay revealed that 8 n displayed acceptable selectivity toward 15 kinases. These results demonstrated that compound 8 n may be a promising potential anticancer agent for further development.

Targeting C/EBPα overcomes primary resistance and improves the efficacy of FLT3 inhibitors in acute myeloid leukaemia.

The outcomes of FLT3-ITD acute myeloid leukaemia (AML) have been improved since the approval of FLT3 inhibitors (FLT3i). However, approximately 30-50% of patients exhibit primary resistance (PR) to FLT3i with poorly defined mechanisms, posing a pressing clinical unmet need. Here, we identify C/EBPα activation as a top PR feature by analyzing data from primary AML patient samples in Vizome. C/EBPα activation limit FLT3i efficacy, while its inactivation synergistically enhances FLT3i action in cellular and female animal models. We then perform an in silico screen and identify that guanfacine, an antihypertensive medication, mimics C/EBPα inactivation. Furthermore, guanfacine exerts a synergistic effect with FLT3i in vitro and in vivo. Finally, we ascertain the role of C/EBPα activation in PR in an independent cohort of FLT3-ITD patients. These findings highlight C/EBPα activation as a targetable PR mechanism and support clinical studies aimed at testing the combination of guanfacine with FLT3i in overcoming PR and enhancing the efficacy of FLT3i therapy.

Structure-Activity Relationship Study of Indolin-5-yl-cyclopropanamine Derivatives as Selective Lysine Specific Demethylase 1 (LSD1) Inhibitors.

LSD1 is identified as an essential drug target, which is closely correlated to the development of several tumor types. In this work, on the basis of comprehensive analysis of the binding site of LSD1 and other FAD-dependent enzymes, a novel series of potent and selective LSD1 inhibitors were designed by incorporation of privileged indoline scaffold strategies. Representative compound 7e (LSD1; IC50 = 24.43 nM, selectivity over LSD2 and MAOs of >200- and 4000-fold) possessed selective antiproliferative activities against MV-4-11 cell lines. Further study indicates that 7e could activate CD86 expression (EC50 = 470 nM) and induce differentiation of AML cell lines. More importantly, compound 7e demonstrated an acceptable oral PK profile and good in vivo antitumor efficacy with a T/C value of 30.89% in an MV-4-11 xenograft mouse model. Collectively, this work provides a promising lead compound for the development of novel LSD1 inhibitors for the treatment of AML.

Design, synthesis and biological evaluation of thioether-containing lenalidomide and pomalidomide derivatives with anti-multiple myeloma activity.

Lenalidomide and its analogs are well-known for treating multiple myeloma. In this work, designed sulfide-modified lenalidomide and pomalidomide were synthesized and evaluated. The anti-proliferative activity against MM.1S cell line of 3ak (IC50 = 79 nM) was similar to lenalidomide (IC50 = 81 nM). Compared to benzylic thioether substituted lenalidomide 3a, the half-live (T1/2) of 4-F-phenyl-thioether analogs 3ak in human liver microsomes was promoted from 3 min to 416.7 min. The corresponding metabolic factor of 3ak was increased from 2.8% to 79.5%, which was slightly lower than lenalidomide (91.5%). Moreover, the IKZF1 degradation of 3y and 3ak was well related with corresponding IC50 values, which suggested the IKZF1 degradation efficiency is correlated to the responses of MM1. S cells. Furthermore, the oral administration of compounds 3y and 3ak at dosages of 60 mg/kg could delay tumor growth in female CB-17 SCID mice. This research helped to prompt the stability of thioether lenalidomide analogs, which paved the way for developing better molecules for treating multiple myeloma.

Sesquiterpene coumarins from Ferula samarkandica Korovin and their bioactivity.

Phytochemical study on the ethanolic extract of the dried roots of Ferula samarkandica Korovin led to the isolation of nine undiscribed sesquiterpene coumarins, samarcandicins A-I, along with thirteen known sesquiterpene coumarins. Their structures were characterized by detailed spectroscopic analysis including NMR and HR-ESI-MS. Mogoltacin and nevskin exhibited high inhibitory activity against MV-4-11 cell with IC50 values of 3.94 ±â€¯0.06 µM and 3.87 ±â€¯0.10 µM, respectively, and nevskin and feshurin showed high inhibitory activity against mino cell with IC50 values of 1.48 ±â€¯0.06 µM and 7.88 ±â€¯0.60 µM, respectively.

Design, Synthesis, and Biological Evaluation of Orally Bioavailable CHK1 Inhibitors Active against Acute Myeloid Leukemia.

Checkpoint kinase 1 (CHK1) is a central component in DNA damage response and has emerged as a target for antitumor therapeutics. Herein, we describe the design, synthesis, and biological evaluation of a novel series of potent diaminopyrimidine CHK1 inhibitors. The compounds exhibited moderate to potent CHK1 inhibition and could suppress the proliferation of malignant hematological cell lines. The optimized compound 13 had a CHK1 IC50 value of 7.73±0.74 nM, and MV-4-11 cells were sensitive to it (IC50 =0.035±0.007 µM). Furthermore, compound 13 was metabolically stable in mouse liver microsomes in vitro and displayed moderate oral bioavailability in vivo. Moreover, treatment of MV-4-11 cells with compound 13 for 2 h led to robust inhibition of CHK1 autophosphorylation on serine 296. Based on these biochemical results, we consider compound 13 to be a promising CHK1 inhibitor and potential anticancer therapeutic agent.

Structure-based design, synthesis and bioactivity evaluation of macrocyclic inhibitors of mutant isocitrate dehydrogenase 2 (IDH2) displaying activity in acute myeloid leukemia cells.

The enzymes involved in the metabolic pathways in cancer cells have been demonstrated as important therapeutic targets such as the isocitrate dehydrogenase 2 (IDH2). A series of macrocyclic derivatives was designed based on the marketed IDH2 inhibitor AG-221 by using the conformational restriction strategy. The resulted compounds showed moderate to good inhibitory potential against different IDH2-mutant enzymes. Amongst, compound C6 exhibited better IDH2R140Q inhibitory potency than AG-221, and showed excellent activity of 2-hydroxyglutarate (2-HG) suppression in vitro and its mesylate displayed good pharmacokinetic profiles. Moreover, C6 performed strong binding mode to IDH2R140Q after computational docking and dynamic simulation, which may serve as a good starting point for further development.

Sulfatase 1 (hSulf-1) reverses basic fibroblast growth factor-stimulated signaling and inhibits growth of hepatocellular carcinoma in animal model.

The human sulfatase 1 (hSulf-1) gene encodes an endosulfatase that functions to inhibit the heparin-binding growth factor signaling, including the basic fibroblast growth factor (bFGF)-mediated pathway, by desulfating the cell surface heparan sulfate proteoglycans (HSPGs). bFGF could stimulate cell cycle progression and inhibit cell apoptosis, this biological effect can be reversed by hSulf-1. However, molecular mechanisms have not been fully reported. In the current study, by reactivation of hSulf-1 expression and function in the hSulf-1-negative hepatocellular carcinoma (HCC) cell lines and HCC xenograft tumors, we found that hSulf-1 blocked the bFGF effect on the promotion of cell cycle and inhibition of apoptosis. The bFGF-stimulated activation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) pathways was suppressed by hSulf-1, which led to a decreased expression of the target genes Cyclin D1 and Survivin, then finally induced cell cycle arrest and apoptosis in HCC cells. Our data suggested that hSulf-1 may be a suitable target for cancer therapy.

MicroRNA-21 suppresses PTEN and hSulf-1 expression and promotes hepatocellular carcinoma progression through AKT/ERK pathways.

MicroRNAs (miRNAs) have been believed to associate with malignant progression including cancer cell proliferation, apoptosis, differentiation, angiogenesis, invasion and metastasis. However, the functions of miRNAs are intricate, one miRNA can directly or indirectly target multiple genes and function as oncogene or tumor suppressor gene. In this study, we found that miR-21 inhibits PTEN and human sulfatase-1 (hSulf-1) expression in hepatocellular carcinoma (HCC) cells. The hSulf-1 is a heparin-degrading endosulfatase, which can inhibit the heparin binding growth factor-mediated signaling transduction into cells. Therefore, miR-21-mediated suppression of both hSulf-1 and PTEN led to activation of AKT/ERK pathways and epithelial-mesenchymal transition (EMT) in HCC cells, and finally enhance the activity of HCC cell proliferation and movement and promote HCC xenograft tumor growth in mouse models. These findings may provide candidate targets for prevention and treatment of HCC.