Design, synthesis and biological activities of Nilotinib derivates as antitumor agents

Novel Compound, ND-17, Regulates the JAK/STAT, PI3K/AKT, and MAPK Pathways and Restrains Human T-Lymphoid Leukemia Development

Background:

T cell acute lymphoblastic leukemia (T-ALL) is an invasive hematological malignant disorder of T cell progenitors. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway plays an important role in the development of T-ALL and in the inhibition of the key molecule, JAK2, and could suppress T-ALL cell proliferation.

Objective:

The objective of this study was to investigate the in vitro anti-tumor effects of a novel nilotinib derivative, ND-17, on cancer cell lines via its interactions with JAK2.

Methods:

The effects of ND-17 on cell proliferation and on cell cycle and apoptosis were evaluated using the tetrazolium assay and flow cytometry, respectively. In addition, the ND-17/JAK2 binding interactions were evaluated using surface plasmon resonance and western blot analyses.

Results:

ND-17 exerted the greatest inhibitory effects on T-ALL cells amongst all hematological cancer cell lines tested. Flow cytometric analysis indicated that ND-17 blocked the cell cycle at the S phase in T-ALL cells. Nilotinib did not significantly inhibit T-ALL cell growth or regulate cell cycle. Preliminary investigations revealed that the regulation of cyclin-dependent kinases/cyclins was attributed to ND-17-induced cell cycle arrest. Furthermore, ND-17 could bind to JAK2 with strong affinity and more importantly, ND-17 bound to the ATP pocket of JAK2 in a manner similar to the potent inhibitor. Thus, ND-17 treatment exhibited a prominent effect in inhibiting the phosphorylation of JAK2 in T-ALL cells. An increase in the phosphorylation of JAK2 was observed in interleukin-6-stimulated Jurkat cells, which was reversed by ND-17 treatment. Meanwhile, the combination of TG-101348 and ND-17 led to further improvement in inhibiting phosphorylation of JAK2. Moreover, the transfection and knockdown of JAK2 altered the inhibitory effect of ND-17 on Jurkat cell viability. In addition, ND-17 treatment suppressed the JAK/STAT, phosphatidylinositol-3-kinase/protein kinase B/mechanistic target of rapamycin, and mitogen-activated protein kinase/extracellular signal-regulated protein kinases 1 and 2 signaling pathways.

Conclusion:

These findings suggest that ND-17 could be a promising JAK2 inhibitor for the treatment of T-ALL.

ND-16: A Novel Compound for Inhibiting the Growth of Cutaneous T Cell Lymphoma by Targeting JAK2

Objective:

Cutaneous T cell lymphoma (CTCL) is a kind of extranodal non-Hodgkin Tcell lymphoma without healable treatment in the clinic. JAK2 amplification in CTCL patients makes it a potential target for CTCL treatment. In the present study, we aimed to evaluate the anticancer effect of ND-16, a novel nilotinib derivate, on CTCL cells and the underlying mechanism targeting JAK2.

Methods and Results:

We found that ND-16 was capable of regulating JAK2 and had a selective inhibitory effect on CTCL H9 cells. The surface plasmon resonance and molecular docking study indicated ND-16 bound to JAK2 with a high binding affinity. Further investigation revealed that ND-16 inhibited the downstream cascades of JAK2, including STATs, PI3K/AKT/mTOR, and MAPK pathways, followed by regulation of Bcl-2 family members and cell cycle proteins CDK/- Cyclins. Flow cytometry analysis confirmed these results that ND-16-treated H9 cells showed cell apoptosis and cell cycle arrest at S-phase.

Conclusion:

ND-16 may be of value in a potential therapy for the management of CTCL

Design, synthesis, and biological evaluation of novel Bcr-AblT315I inhibitors incorporating amino acids as flexible linker

Despite the success of imatinib in CML therapy through Bcr-Abl inhibition, acquired drug resistance occurs over time in patients. In particular, the resistance caused by T315I mutation remains a challenge in clinic. Herein, we embarked on a structural optimization campaign aiming at discovery of novel Bcr-Abl inhibitors toward T315I mutant based on previously reported dibenzoylpiperazin derivatives. We proposed that incorporation of flexible linker could achieve potent inhibition of Bcr-Abl^T315I by avoiding steric clash with bulky sidechain of Ile315. A library of 28 compounds with amino acids as linker has been developed and evaluated. Among them, compound AA2 displayed the most potent activity against Bcr-Abl^WT and Bcr-Abl^T315I, as well as toward Bcr-Abl driven K562 and K562R cells. Further investigations indicated that AA2 could induce apoptosis of K562 cells and down regulate phosphorylation of Bcr-Abl. In summary, the compounds with amino acid as novel flexible linker exhibited certain antitumor activities, providing valuable hints for the discovery of novel Bcr-Abl inhibitors to overcome T315I mutant resistance, and AA2 could be considered as a candidate for further optimization.

Design, synthesis, and biological evaluation of 5-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)-1H-Indole-2-Carbohydrazide derivatives: the methuosis inducer 12A as a Novel and selective anticancer agent

This study describes the synthesis and vacuole-inducing activity of 5-((4-(pyridin-3-yl)pyrimidin-2-yl)amino)-1H-indole-2-carbohydrazide derivatives, including five potent derivatives 12c, 12 g, 12i, 12n, and 12A that exhibit excellent vacuole-inducing activity. Remarkably, 12A effectively induces methuosis in tested cancer cells but not human normal cells. In addition, 12A exhibits high pan-cytotoxicity against different cancer cell lines but is hardly toxic to normal cells. It is found that the 12A-induced vacuoles are derived from macropinosomes but not autophagosomes. The 12A-induced cytoplasmic vacuoles may originate from the endoplasmic reticulum (ER) and be accompanied by ER stress. The MAPK/JNK signalling pathway is involved in the 12A-induced methuotic cell death. Moreover, 12A exhibits significant inhibition of tumour growth in the MDA-MB-231 xenograft mouse model. The excellent potency and selectivity of 12A prompt us to select it as a good lead compound for further development of methuosis inducers and investigation of the molecular and cellular mechanisms underlying methuosis.

ND‑09 inhibits chronic myeloid leukemia K562 cell growth by regulating BCR‑ABL signaling

Chronic myeloid leukemia (CML) accounts for approximately 15% of new adult leukemia cases. The fusion gene BCR‑ABL is an important biological basis and target for CML. In the present study, a novel compound, ND‑09, was developed and its inhibitory effect and mechanism of action on CML growth were evaluated using RT‑PCR and western blot analysis. The results showed that ND‑09 demonstrated a high level of inhibitory action toward CML cells overexpressing BCR‑ABL and induced K562 cell apoptosis through the mitochondrial pathway. Notably, combined ND‑09 and BCR‑ABL siRNA treatment could better inhibit cell proliferation and induce apoptosis in K562 cells. Furthermore, this growth effect of BCR‑ABL siRNA could be fully rescued by transfection with BCR‑ABL. ND‑09 exhibited a good fit within BCR‑ABL and occupied its ATP‑binding pocket, thus altering BCR‑ABL kinase activity. Therefore, ND‑09 downregulated the phosphorylation of BCR‑ABL and ABL, ultimately inhibiting the downstream signaling pathways in K562 cells. These findings suggest that ND‑09 induces growth arrest in CML cells by targeting BCR‑ABL.

Discovery of novel Bcr-AblT315I inhibitors with flexible linker. Part 1: Confirmation optimization of phenyl-1H-indazol-3-amine as hinge binding moiety

As a continuation to our research, a series of novel Bcr-Abl inhibitors incorporated with 6-phenyl-1H-indazol-3-amine as hinge binding moiety (HBM) were developed based on confirmation analysis. Biological results indicated that these compounds exhibited an enhanced inhibition against Bcr-Abl^WT and Bcr-Abl^T315I in kinases assays, along with improved anti-proliferative activities in K562 cell assays. In particular, compound Y9 displayed comparable potency with that of imatinib. It potently inhibited Bcr-Abl^WT and Bcr-Abl^T315I kinases with IC₅₀ of 0.043 μM and 0.17 μM, respectively. Furthermore, compound Y9 inhibited the proliferation of K562 and K562R cells with IC₅₀ of 1.65 μM and 5.42 μM, respectively. Therefore, 6-phenyl-1H-indazol-3amine as HBM, combined with flexible linker, is a successful strategy contribute to research on T315I mutant resistance, and compound Y9 could be served as a starting point for further optimization.

Discovery of novel anti-angiogenesis agents. Part 8: Diaryl thiourea bearing 1H-indazole-3-amine as multi-target RTKs inhibitors

VEGFR-2, TIE-2, and EphB4 are essential for both angiogenesis and tumorigenesis. Herein, we designed and prepared three classes of multi-target inhibitors based on the extensive sequence homology along the kinase domain of angiogenic RTKs. Biological evaluation indicated that these multi-target inhibitors exhibited considerable potential as novel anti-angiogeneic and anticancer agents. Among them, a diaryl thiourea bearing 1H-indazole-3-amine (16a) displayed the most potent RTK inhibition and excellent selectivity. It also showed inhibition on viability of human umbilical vein endothelial cells and anti-proliferation against a broad spectrum of cancer cells. Therefore, 1H-indazole-3-amine could serve as a promising hinge binding group for multi-target inhibitors of VEGFR-2, Tie-2, and EphB4.

Discovery and evaluation of triple inhibitors of VEGFR-2, TIE-2 and EphB4 as anti-angiogenic and anti-cancer agents

Receptor tyrosine kinases (RTKs), especially VEGFR-2, TIE-2, and EphB4, play a crucial role in both angiogenesis and tumorigenesis. Moreover, complexity and heterogeneity of angiogenesis make it difficult to treat such pathological traits with single-target agents. Herein, we developed two classes of multi-target RTK inhibitors (RTKIs) based on the highly conserved ATP-binding pocket of VEGFR-2/TIE-2/EphB4, using previously reported BPS-7 as a lead compound. These multi-target RTKIs exhibited considerable potential as novel anti-angiogenic and anticancer agents. Among them, QDAU5 displayed the most promising potency and selectivity. It significantly suppressed viability of EA.hy926 and proliferation of several cancer cells. Further investigations indicated that QDAU5 showed high affinity to VEGFR-2 and reduced the phosphorylation of VEGFR-2. We identified QDAU5 as a potent multiple RTKs inhibitor exhibiting prominent anti-angiogenic and anticancer potency both in vitro and in vivo. Moreover, quinazolin-4(3H)-one has been identified as an excellent hinge binding moiety for multi-target inhibitors of angiogenic VEGFR-2, Tie-2, and EphB4.

Expanding the structural diversity of Bcr-Abl inhibitors: Hybrid molecules based on GNF-2 and Imatinib

In order to expand the structural diversity of Bcr-Abl inhibitors, twenty hybrids (series E and P) have been synthesized and characterized based on Imatinib and GNF-2. Their biological activities were evaluated in vitro against human leukemia cells. Most compounds exhibited potent antiproliferative activity against K562 cells, especially for compounds E4, E5 and E7. Furthermore, these new hybrids were also screened for Abl kinase inhibitory activity, and some of them inhibited Abl kinase with low micromolar IC50 values. In particular, compound P3 displayed the most potent activity with IC50 value of 0.017 μM comparable with that of Imatinib. Molecular docking studies indicated that these novel hybrids fitted well with the active site of Bcr-Abl. These results suggested the great potential of these compounds as novel Bcr-Abl inhibitors.

Discovery of biphenyl-aryl ureas as novel VEGFR-2 inhibitors. Part 4: exploration of diverse hinge-binding fragments

VEGFR-2 plays an essential role in angiogenesis and is an important target for cancer therapy. A series of biphenyl-aryl ureas were synthesized and evaluated as novel VEGFR-2 inhibitors. The pyridine, methylamine carbonyl pyridine and pivaloyl amide pyridine were introduced as novel hinge binding fragment. The majority of title compounds displayed potent VEGFR-2 inhibition. In particular, L1, L9, W14 and W15 exhibited significant enzymatic inhibitory activity with IC50 values of 0.36nM, 0.22nM, 0.15nM and 0.14nM. Compounds L1, L9 and W15 displayed potent antiproliferative activity against A549 and SMMC-7721 cells. SAR study suggested that incorporation of 3-trifluoromethyl and methylamine carbonyl on terminal pyridine could improve VEGFR-2 inhibitory activity. Molecular docking illustrated that urea moiety formed two critical hydrogen bonds with the DFG residues of VEGFR-2. The results indicated that these biphenyl-aryl ureas could serve as promising lead compounds for further optimization.

Discovery of biphenyl-based VEGFR-2 inhibitors. Part 3: design, synthesis and 3D-QSAR studies

VEGFR-2 plays an essential role in angiogenesis and is a central target for anticancer drug discovery. In order to develop novel VEGFR-2 inhibitors, we designed and synthesized 33 biphenyl amides based on our previously reported lead compound. The biological results indicated that four compounds (18b, 20e, 20h and 20j) are potent VEGFR-2 inhibitors which are comparable to positive control. Compound 18b displayed the most potent VEGFR-2 inhibition with IC50 value of 2.02nM. Moreover, it exhibited promising antiproliferative activity against MCF-7 and SMMC-7721 cells with IC50 values of 1.47μM and 5.98μM, respectively. Molecular docking and 3D-QSAR studies were also carried out. The results indicated that these biphenyl amides could serve as promising leads for further optimization as novel VEGFR-2 inhibitors.

Discovery of novel Bcr-Abl inhibitors with diacylated piperazine as the flexible linker

Forty-two compounds with flexible diacylated piperazine linkers were designed, synthesized and evaluated as novel Bcr-Abl inhibitors.

Discovery of novel Bcr-Abl inhibitors targeting myristoyl pocket and ATP site

Bcr-Abl plays an essential role in the pathogenesis and development of chronic myeloid leukaemia (CML). Inhibition of Bcr-Abl has great potential for therapeutic intervention in CML. In order to obtain novel and potent Bcr-Abl inhibitors, twenty seven 4,6-disubstituted pyrimidines were synthesized and evaluated herein. The biological results indicated that four compounds of them (C4, C5, C16, and C23) were potent Bcr-Abl inhibitors which were comparable to positive control. Moreover, C4 and C5 displayed promising antiproliferative activity against K562 cells. The results suggested that these 4,6-disubstituted pyrimidines could serve as promising leads for further optimization of Bcr-Abl inhibitors.