Nilotinib: a phenylamino-pyrimidine derivative with activity against BCR-ABL, KIT and PDGFR kinases

Rapamycin vs TORin-1 or Gleevec vs Nilotinib: Simple chemical evolution that converts PAK1-blockers to TOR-blockers or vice versa?

Both PAK1 (RAC/CDC42-activating kinase 1) and TOR (Target of Rapamycin) are among the major oncogenic/ageing kinases. However, they play the opposite role in our immune system, namely immune system is suppressed by PAK1, while it requires TOR. Thus, PAK1-blockers, would be more effective for therapy of cancers, than TOR-blockers. Since 2015 when we discovered genetically that PDGF-induced melanogenesis depends on "PAK1", we are able to screening a series of PAK1-blockers as melanogenesis-inhibitors which could eventually promote longevity. Interestingly, rapamycin, the first TOR-inhibitor, promotes melanogenesis, clearly indicating that TOR suppresses melanogenesis. However, a new TOR-inhibitor called TORin-1 no longer suppresses immune system, and blocks melanogenesis in cell culture. These observations strongly indicate that TORin-1 acts as PAK1-blockers, instead of TOR-blockers, in vivo. Thus, it is most likely that melanogenesis in cell culture could enable us to discriminate PAK1-blockers from TORblockers.

Tyrosine kinases in the pathogenesis of tissue fibrosis in systemic sclerosis and potential therapeutic role of their inhibition

Systemic sclerosis (SSc) is an idiopathic autoimmune disease with a heterogeneous clinical phenotype ranging from limited cutaneous involvement to rapidly progressive diffuse SSc. The most severe SSc clinical and pathologic manifestations result from an uncontrolled fibrotic process involving the skin and various internal organs. The molecular mechanisms responsible for the initiation and progression of the SSc fibrotic process have not been fully elucidated. Recently it has been suggested that tyrosine protein kinases play a role. The implicated kinases include receptor-activated tyrosine kinases and nonreceptor tyrosine kinases. The receptor kinases are activated following specific binding of growth factors (platelet-derived growth factor, fibroblast growth factor, or vascular endothelial growth factor). Other receptor kinases are the discoidin domain receptors activated by binding of various collagens, the ephrin receptors that are activated by ephrins and the angiopoetin-Tie-2s receptors. The nonreceptor tyrosine kinases c-Abl, Src, Janus, and STATs have also been shown to participate in SSc-associated tissue fibrosis. Currently, there are no effective disease-modifying therapies for SSc-associated tissue fibrosis. Therefore, extensive investigation has been conducted to examine whether tyrosine kinase inhibitors (TKIs) may exert antifibrotic effects. Here, we review the role of receptor and nonreceptor tyrosine kinases in the pathogenesis of the frequently progressive cutaneous and systemic fibrotic alterations in SSc, and the potential of TKIs as SSc disease-modifying antifibrotic therapeutic agents.

Nilotinib, A Tyrosine Kinase Inhibitor, Suppresses the Cell Growth and Triggers Autophagy in Papillary Thyroid Cancer

BACKGROUND

Papillary thyroid carcinoma (PTC) represents for the most common thyroid cancer. Until recently, treatment options for PTC patients are limited. Nilotinib is the second-generation tyrosine kinase inhibitor, and has been widely used in the treatment of chronic myeloid leukemia (CML).

OBJECTIVES

We aimed to explore whether nilotinib is effective in PTC cancer progression and the underlying mechanisms.

METHODS

In this study, the three human PTC cell lines (KTC-1, BCPAP, and TPC1) were used to verify the effects of nilotinib on cell growth. The half maximal inhibitory concentration (IC50) was calculated according to the growth curve post nilotinib treatment at different concentrations. Cell counting kit-8 and colony formation analysis were used to monitor cell growth after nilotinib treatment. Cell apoptosis and autophagy related proteins and phosphorylation of PI3K/Akt/mTOR were detected by Western blotting analysis.

RESULTS

Nilotinib treatment can effectively inhibit PTC cell growth, which was accompanied by increase of apoptosis and induction of autophagy. Mechanistically, nilotinib treatment repressed the phosphorylation of PI3K/Akt/mTOR pathway.

CONCLUSION

Collectively, our results demonstrated that nilotinib may display anti-tumor effect against PTC via inhibiting of PI3K/Akt/mTOR pathway and inducing apoptosis and autophagy.

Adverse events associated with nilotinib in chronic myeloid leukemia: mechanisms and management strategies

Introduction: Nilotinib is a second-generation tyrosine kinase inhibitor (TKI) targeting BCR/ABL, which is used for the first-line treatment of newly diagnosed chronic myeloid leukemia (CML) patients and the second-line treatment of most CML patients who are resistant or intolerant to prior therapy that includes imatinib. In addition to common adverse reactions, long-term use of nilotinib shows some toxicities that are different from those of occurring during other BCR/ABL TKI treatments, such as cardiovascular toxicity. It is life-threatening, which would affect not only the choice of initial treatment of CML patients but also the safety of long-term medication.Areas covered: Through searching literature and reports from PubMed and clinical trials, here we review a profile of the adverse effects induced by nilotinib. We also discuss the potential molecular toxicological mechanisms and clinical management, which may provide strategies to prevent or intervene the toxicity associated with nilotinib.Expert opinion: Severe adverse effects associated with nilotinib limit its long-term clinical application. However, the exact mechanisms underlying these toxicities remain unclear. Future research should focus on the developing strategies to reduce the toxicities of nilotinib as well as to avoid similar toxicity in the development of new drugs.

Pharmacological inhibitors of c-KIT block mutant c-KIT mediated migration of melanocytes and melanoma cells in vitro and in vivo

Mutations in the receptor tyrosine kinase c-KIT (KIT) are frequent oncogenic alterations in melanoma and are predominantly detected in tumors of acral, mucosal, and chronically sun-damaged skin. Research indicates that melanocytes with aberrant KIT signaling can be found in the distant periphery of the primary tumor; However, it is hitherto unknown whether KIT might confer a migratory advantage, thereby enabling genetically abnormal cells to populate a distal area. In this study, we investigated the role of mutant KIT in melanocyte- and melanoma cell migration using KIT mutant lines as well as genetically manipulated murine and primary human melanocytes. Our results revealed that melanocytes, stably transduced with mutant KIT closed a gap inflicted on cell monolayers faster than wild-type controls. Similarly, KIT mutant human melanoma lines were able to populate a larger area in a 3D in vitro skin model compared to KIT wild type and BRAF mutant lines. Genomic profiling revealed that genes associated with increased cell-dispersal of KIT mutant variants were linked to a statistically significant up-regulation of 60 migratory genes (z-score 1.334; p=0.0001). In addition, in vivo experiments harnessing a mouse xenograft model of early melanoma development demonstrated rapid lateral migration of KIT mutant cells compared to respective controls. The specific kinase inhibitors imatinib and nilotinib, could abrogate this migratory advantage in vitro and in vivo. Our work suggests that KIT inhibition might help to target migratory active, KIT mutant melanoma cells, thus representing a potential strategy to reduce spread and local recurrence.

Design, Synthesis and Antibacterial Evaluation of Novel 1,2,3-Triazole Derivatives Incorporating 3′-Deoxythymidine

A series of novel 1,2,3-triazole derivatives incorporating 3′-deoxythymidine were designed, synthesised and characterised. Antibacterial activity against Escherichia coli and Staphylococcus aureus was evaluated for all of the synthesised compounds and compared against standard antibiotic drugs, streptomycin sulfate and doxycycline, as controls. Some compounds showed potential antibacterial activity towards E. coli, and the best minimum inhibitory concentration was 0.14 mM. Preliminary structure-activity relationships and computational simulations were also studied.

Nilotinib-induced vasculopathy: identification of vascular endothelial cells as a primary target site

The BCR/ABL1 inhibitor Nilotinib is increasingly used to treat patients with chronic myeloid leukemia (CML). Although otherwise well-tolerated, Nilotinib has been associated with the occurrence of progressive arterial occlusive disease (AOD). Our objective was to determine the exact frequency of AOD and examine in vitro and in vivo effects of Nilotinib and Imatinib on endothelial cells to explain AOD-development. In contrast to Imatinib, Nilotinib was found to upregulate pro-atherogenic adhesion-proteins (ICAM-1, E-selectin, VCAM-1) on human endothelial cells. Nilotinib also suppressed endothelial cell proliferation, migration and tube-formation, and bound to a distinct set of target-kinases, relevant to angiogenesis and atherosclerosis, including angiopoietin receptor-1 TEK, ABL-2, JAK1, and MAP-kinases. Nilotinib and siRNA against ABL-2 also suppressed KDR expression. In addition, Nilotinib augmented atherosclerosis in ApoE-/- mice and blocked reperfusion and angiogenesis in a hind-limb-ischemia model of arterial occlusion, whereas Imatinib showed no comparable effects. Clinically overt AOD-events were found to accumulate over time in Nilotinib-treated patients. After a median observation-time of 2.0 years, the AOD-frequency was higher in these patients (29.4%) compared to risk factor- and age-matched controls (<5%). Together, Nilotinib exerts direct pro-atherogenic and anti-angiogenic effects on vascular endothelial cells, which may contribute to development of AOD in patients with CML.

Nilotinib induces autophagy in hepatocellular carcinoma through AMPK activation

Hepatocellular carcinoma (HCC) is the most common liver cancer and the third-leading cause of cancer death worldwide. Nilotinib is an orally available receptor tyrosine kinase inhibitor approved for chronic myelogenous leukemia. This study investigated the effect of nilotinib on HCC. Nilotinib did not induce cellular apoptosis. Instead, staining with acridine orange and microtubule-associated protein 1 light chain 3 revealed that nilotinib induced autophagy in a dose- and time-dependent manner in HCC cell lines, including PLC5, Huh-7, and Hep3B. Moreover, nilotinib up-regulated the phosphryaltion of AMP-activated kinase (AMPK) and protein phosphatase PP2A inactivation were detected after nilotinib treatment. Up-regulating PP2A activity suppressed nilotinib-induced AMPK phosphorylation and autophagy, suggesting that PP2A mediates the effect of nilotinib on AMPK phosphorylation and autophagy. Our data indicate that nilotinib-induced AMPK activation is mediated by PP2A, and AMPK activation and subsequent autophagy might be a major mechanism of action of nilotinib. Growth of PLC5 tumor xenografts in BALB/c nude mice was inhibited by daily oral treatment with nilotinib. Western blot analysis showed both increased phospho-AMPK expression and decreased PP2A activity in vivo. Together, our results reveal that nilotinib induces autophagy, but not apoptosis in HCC, and that the autophagy-inducing activity is associated with PP2A-regulated AMPK phosphorylation.

FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.

Activity-based kinase profiling of approved tyrosine kinase inhibitors

The specificities of nine approved tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib, gefitinib, erlotinib, lapatinib, sorafenib, sunitinib, and pazopanib) were determined by activity-based kinase profiling using a large panel of human recombinant active kinases. This panel consisted of 79 tyrosine kinases, 199 serine/threonine kinases, three lipid kinases, and 29 disease-relevant mutant kinases. Many potential targets of each inhibitor were identified by kinase profiling at the K(m) for ATP. In addition, profiling at a physiological ATP concentration (1 mm) was carried out, and the IC(50) values of the inhibitors against each kinase were compared with the estimated plasma-free concentration (calculated from published pharmacokinetic parameters of plasma C(trough) and C(max) values). This analysis revealed that the approved kinase inhibitors were well optimized for their target kinases. This profiling also implicates activity at particular off-target kinases in drug side effects. Thus, large-scale kinase profiling at both K(m) and physiological ATP concentrations could be useful in characterizing the targets and off-targets of kinase inhibitors.

Multi-target drugs: the trend of drug research and development

Summarizing the status of drugs in the market and examining the trend of drug research and development is important in drug discovery. In this study, we compared the drug targets and the market sales of the new molecular entities approved by the U.S. Food and Drug Administration from January 2000 to December 2009. Two networks, namely, the target–target and drug–drug networks, have been set up using the network analysis tools. The multi-target drugs have much more potential, as shown by the network visualization and the market trends. We discussed the possible reasons and proposed the rational strategies for drug research and development in the future.

Nilotinib counteracts P-glycoprotein-mediated multidrug resistance and synergizes the antitumoral effect of doxorubicin in soft tissue sarcomas

The therapeutic effect of doxorubicin (DXR) in the treatment of soft tissue sarcomas (STS) is limited by its toxicity and the development of multidrug resistance (MDR), the latter mainly induced by high expression of efflux pumps (e.g., P-glycoprotein [P-gp]). Therefore, the search for alternative therapies, which sensitize these tumors to chemotherapy while maintaining a low toxicity profile, is a rational approach. We assessed efficacy and molecular mechanisms involved in the antiproliferative effects of the tyrosine kinase inhibitors, nilotinib and imatinib, as single agents or in combination with DXR, in human synovial sarcoma SW982 and leiomyosarcoma SK-UT-1 cells. As single compound nilotinib (1-10 µM) was more potent than imatinib inhibiting the growth of SK-UT-1 and SW982 cells by 33.5-59.6%, respectively. Importantly, only nilotinib synergized the antitumoral effect of DXR (0.05-0.5 µM) by at least 2-fold, which clearly surpassed the mere sum of effects according to isobolographic analysis. Moreover, nilotinib in combination with DXR had a sustained effect on cell number (-70.3±5.8%) even 12 days after withdrawal of drugs compared to DXR alone. On the molecular level, only nilotinib fully blocked FBS-induced ERK1 and p38 MAPK activation, hence, reducing basal and DXR-induced up-regulation of P-gp levels. Moreover, efflux activity of the MDR-related proteins P-gp and MRP-1 was inhibited, altogether resulting in intracellular DXR retention. In high-risk STS tumors 53.8% and 15.4% were positive for P-gp and MRP-1 expression, respectively, with high incidence of P-gp in synovial sarcoma (72.7%). In summary, nilotinib exhibits antiproliferative effects on cellular models of STS and sensitizes them to DXR by reverting DXR-induced P-gp-mediated MDR and inhibiting MRP-1 activity, leading to a synergistic effect with potential for clinical treatment.

The effects of chemotherapeutic agents on differentiated chordoma cells

OBJECT

Chordoma is a rare type of malignant bone tumor and is known to arise from the remnants of the notochord. Resistance to chemotherapy makes the treatment of chordoma difficult; therefore, new approaches need to be developed to cure this disease. Differentiation therapy, using various differentiating agents, is attracting oncologists as a common therapeutic method to treat other tumors. Based on forcing cells to mature into other lineages, differentiation therapy might be an available method to treat chordomas in addition to conventional therapies.

METHODS

In this study a chordoma cell line, U-CH1, was exposed to several chemotherapeutic agents including vincristine, doxorubicin, cisplatin, etoposide, fludarabine, methotrexate, nilotinib, and imatinib mesylate under appropriate conditions. The first group of U-CH1 cells was exposed to drugs only and the second group of cells was exposed to the simultaneous treatment of 1 μM all-trans retinoic acid (ATRA) and chemotherapeutic agents in differentiation therapy. The efficacy of the differentiation method was assessed by measuring the viability of U-CH1 cells.

RESULTS

Vincristine, doxorubicin, etoposide, cisplatin, and fludarabine, each at a concentration of 10 μM, decreased the number of chordoma cells when given alone down to 11%, 0%, 30%, 67%, and 3%, respectively. Etoposide and cisplatin, each at a concentration of 10 μM, reduced the percentage of viable chordoma cells in a more effective way when given with 1 μM ATRA simultaneously, reducing the number of viable cells to 14% and 9%, respectively. On the other hand, imatinib and nilotinib, each at a concentration of 3 μM, as well as 10 μM methotrexate, showed no decrease in the number of cancer cells.

CONCLUSIONS

The results suggest that chordoma cells may be treated using the differentiation method in a more effective way than when they are treated with chemotherapeutic agents alone. This new approach may be an alternative method to conventional therapies in the treatment of chordoma.

Progressive peripheral arterial occlusive disease and other vascular events during nilotinib therapy in CML

The second generation BCR/ABL kinase inhibitor nilotinib is increasingly used for the treatment of imatinib-resistant chronic myeloid leukemia (CML). So far, nilotinib is considered a well-tolerated drug with little if any side effects, although an increase in the fasting glucose level has been reported. We examined a series of 24 consecutive CML patients treated with nilotinib in our center for the development of non-hematologic adverse events. Three of these 24 CML patients developed a rapidly progressive peripheral arterial occlusive disease (PAOD) during treatment with nilotinib. In all three cases, PAOD required repeated angioplasty and/or multiple surgeries within a few months. No PAOD was known before nilotinib-therapy in these patients, although all three had received imatinib. In two patients, pre-existing risk factors predisposing for PAOD were known, and one of them had developed diabetes mellitus during nilotinib. In the other 21 patients treated with nilotinib in our center, one less severe PAOD, one myocardial infarction, one spinal infarction, one subdural hematoma, and one sudden death of unknown etiology were recorded. In summary, treatment with nilotinib may be associated with an increased risk of vascular adverse events, including PAOD development. In a subgroup of patients, these events are severe or even life-threatening. Although the exact mechanisms remain unknown, we recommend screening for pre-existing PAOD and for vascular risk factors such as diabetes mellitus in all patients before starting nilotinib and in the follow up during nilotinib-therapy.

Angiostatic effects of K252a, a Trk inhibitor, in murine brain capillary endothelial cells

Nerve growth factor (NGF) supports the survival and differentiation of sympathetic and sensory neurons and is also mitogenic for a variety of tumors. K252a, an antagonist of NGF receptor TrkA, was previously used as a pharmacological tool to study NGF actions and as a lead compound for developing anti-tumor drugs. Since recently, NGF was characterized as an angiogenic factor, we sought to investigate the angiostatic properties of K252a on endothelial cells (ECs). For this purpose, we used a murine brain microcapillary ECs model in which we found autocrine release of NGF in the culture medium and activation of TrkA receptor-induced downstream signaling molecules Erk1/2, Akt, and PLCgamma. In this model, we demonstrated the angiostatic property of K252a based on its ability to affect several important angiogenic steps. K252a, but not its cell membrane impermeable analogue K252b at 100 nM: (i) inhibited the proliferation of the ECs by 45 +/- 9%; (ii) reduced by 70 +/- 4% the migration of the ECs measured in a wound-closure model; (iii) reduced by 29 +/- 9% the formation of tube-like structures of the ECs cultured on Matrigel; (iv) stimulated by 100 +/- 25% the collagen deposition by the ECs, a process responsible for the increased endothelial barrier functions expressed by 22 +/- 5% reduction of paracellular permeability and by 17 +/- 3% elevation of transendothelial electrical resistance. These data suggest that NGF/TrkA may represent a target for the development of novel, K252a-derived multikinase inhibitors drugs with anti-tumor and angiostatic dual activities.

Translational research in complex etiopathogenesis and therapy of hematological malignancies: the specific role of tyrosine kinases signaling and inhibition

During the recent genomics and proteomics era, high-resolution, genome-wide approaches have revealed numerous promising new drug targets and disease biomarkers, accelerating and emphasizing the need for targeted molecular therapy compounds. Significant progress has been made in understanding the pathogenesis of hematological malignancies there by, revealing new drug targets. Introduction of multiple new technologies in cancer research have significantly improved the drug discovery process, leading to key success in targeted cancer therapeutics, including tyrosine kinase inhibitors. The studies of receptor tyrosine kinases and their role in malignant transformation are already translated from the preclinical level (cell-based and animal models) to clinical studies, enabling the more complete understanding of tumor cell biology and improvement of tumor therapy.