Fasting glucose improvement under dasatinib treatment in an accelerated phase chronic myeloid leukemia patient unresponsive to imatinib and nilotinib

Glycaemic abnormalities induced by small molecule tryosine kinase inhibitors: a review

In light of the expected increase in the prevalence of diabetes mellitus due to an aging population, sedentary lifestyles, an increase in obesity, and unhealthy diets, there is a need to identify potential pharmacological agents that can heighten the risk of developing diabetes. Similarly, it is equally important to also identify those agents that show blood glucose-lowering properties. Amongst these agents are tyrosine kinase inhibitors used to treat certain types of cancers. Over the last two decades, there has been an increase in the use of targeted chemotherapy for cancers such as renal cell carcinoma, chronic leukaemia, and gastrointestinal stromal tumours. Small molecule tyrosine kinase inhibitors have been at the forefront of targeted chemotherapy. Studies have shown that small molecule tyrosine kinase inhibitors can alter glycaemic control and glucose metabolism, with some demonstrating hypoglycaemic activities whilst others showing hyperglycaemic properties. The mechanism by which small molecule tyrosine kinase inhibitors cause glycaemic dysregulation is not well understood, therefore, the clinical significance of these chemotherapeutic agents on glucose handling is also poorly documented. In this review, the effort is directed at mapping mechanistic insights into the effect of various small molecule tyrosine kinase inhibitors on glycaemic dysregulation envisaged to provide a deeper understanding of these chemotherapeutic agents on glucose metabolism. Small molecule tyrosine kinase inhibitors may elicit these observed glycaemic effects through preservation of β-cell function, improving insulin sensitivity and insulin secretion. These compounds bind to a spectrum of receptors and proteins implicated in glucose regulation for example, non-receptor tyrosine kinase SRC and ABL. Then receptor tyrosine kinase EGFR, PDGFR, and FGFR.

Future treatment of Diabetes - Tyrosine Kinase inhibitors

Background

Diabetes mellitus (DM) is a group of metabolic disorders that have an increased risk of macro and micro-vascular complications due to lipid dysfunction. The present drug treatments for the management of DM either have numerous side effects or do not have long-lasting therapeutic effects. So it is essential to find a newer class of drug for DM treatment.

Method

Broad information has been researched regarding Tyrosine kinase Inhibitors (TKIs) and their mechanism of action. They are proven for the management of various kinds of cancers. TKIs produce anti-hyperglycemic effects by acting on multiple targets such as c-Abl, Platelet-Derived Growth Factor Receptor (PDGFR), Vascular Endothelial Growth Factor Receptor (VEGFR), Epidermal Growth Factor Receptor (EGFR), and c-Kit.

Result

This family of drugs blocks numerous tyrosine kinases by acting as a partial agonist of PPAR-γ receptors and results in an anti-diabetic effect by improving insulin sensitivity and glucose disposal rate.

Conclusion

Therefore, it is said that TKI drugs will be great potential for the treatment of Diabetes. This review summarizes the possible targets of TKIs and TKIs being a potential drug class in the management of Diabetes mellitus.

Senolytics dasatinib and quercetin in idiopathic pulmonary fibrosis: results of a phase I, single-blind, single-center, randomized, placebo-controlled pilot trial on feasibility and tolerability

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an age-related, chronic, irreversible fibrotic lung disease. IPF is associated with increased senescent cells burden, which may be alleviated with administration of senescent cell targeting drugs termed 'senolytics'. We previously conducted an open-label single-arm pilot study of the senolytic combination of dasatinib and quercetin (D + Q) in patients with IPF but lack of control group limited interpretation and next-stage trial planning. The primary objective of this confirmatory randomized placebo-controlled pilot trial (RCT; NCT02874989) was to report adverse events with D + Q and inform study feasibility for future efficacy trials.

METHODS

Twelve participants with IPF aged >50 years were blinded and randomized at a 1:1 ratio to either receive three weeks of D + Q (D: 100 mg/d and Q: 1250 mg/d, three consecutive days per week) or matching placebo.

FINDINGS

All participants completed the scheduled drug dosing regimen (108/108 doses) and planned assessments (60/60). While the placebo arm reported fewer overall non-serious AEs (65 vs 22), there were no serious adverse events related to D + Q. Most AEs in the D + Q arm are common in IPF patients or anticipated side effects of D. Sleep disturbances and anxiety were disproportionately represented in the D + Q arm (4/6 vs 0/6). Frailty, pulmonary, or physical function were explored before and after intermittent D + Q; though under-powered to evaluate change, these measures do not appear to differ meaningfully between groups.

INTERPRETATION

Intermittently-dosed D + Q in patients with IPF is feasible and generally well-tolerated. Further prospective studies, such as a larger RCT, are needed to confirm the safety and efficacy of D + Q in patients with IPF.

FUNDING

This work was supported by National Institutes of Health grants R33AG61456 (JLK, TT), Robert and Arlene Kogod (JLK, TT), the Connor Fund (JLK, TT), Robert J. and Theresa W. Ryan (JLK, TT), and the Noaber Foundation (JLK, TT) San Antonio Claude D. Pepper Older Americans Independence Center's (OAIC)Pilot/Exploratory Studies Core (PESC) Grant (AMN, NM); NIHK01 AG059837 (JNJ), P30 AG021332 (SBK, JNJ); NIHR37 AG013925 (JLK), the Connor Group (JLK), Glenn/AFAR BIG Award (JLK), Robert J. and Theresa W. Ryan (JLK), and the Noaber and Ted Nash Long Life Foundations (JLK).

Sorafenib decreases glycemia by impairing hepatic glucose metabolism

PURPOSE

Sorafenib has been reported to reduce blood glucose levels in diabetic and non-diabetic patients in previous retrospective studies. However, the mechanism of which the hypoglycemic effects of sorafenib is not clearly explored. In this study, we investigated the effect of sorafenib on blood glucose levels in diabetic and normal mice and explored the possible mechanism.

METHODS

We established a mouse model of type 2 diabetes by a high-fat diet combined with a low-dose of streptozotocin (STZ), to identify the hypoglycemic effect of sorafenib in different mice. Glucose tolerance, insulin tolerance and pyruvate tolerance tests were done after daily gavage with sorafenib to diabetic and control mice. To explore the molecular mechanism by which sorafenib regulates blood glucose levels, hepatic glucose metabolism signaling was studied by a series of in vivo and in vitro experiments.

RESULTS

Sorafenib reduced blood glucose levels in both control and diabetic mice, particularly in the latter. The diabetic mice exhibited improved glucose and insulin tolerance after sorafenib treatment. Further studies showed that the expressions of gluconeogenesis-related enzymes, such as PCK1, G6PC and PCB, were significantly decreased upon sorafenib treatment. Mechanistically, sorafenib downregulates the expression of c-MYC downstream targets PCK1, G6PC and PCB through blocking the ERK/c-MYC signaling pathway, thereby playing its hypoglycemic effect by impairing hepatic glucose metabolism.

CONCLUSION

Sorafenib reduces blood glucose levels through downregulating gluconeogenic genes, especially in diabetic mice, suggesting the patients with T2DM when treated with sorafenib need more emphasis in monitoring blood glucose to avoid unnecessary hypoglycemia.

Tyrosine kinase targeting: A potential therapeutic strategy for diabetes

Tyrosine kinase inhibitors (TKIs) have been studied extensively in cancer research, ultimately resulting in the approval of many drugs for cancer therapy. Recent evidence from reported clinical cases and experimental studies have suggested that some of these drugs have a potential role in diabetes treatment. These TKIs include imatinib, sunitinib, dasatinib, erlotinib, nilotinib, neratinib, and ibrutinib. As a result of promising findings, imatinib has been used in a phase II clinical trial. In this review, studies that used TKIs in the treatment of both types of diabetes are critically discussed. In addition, the different molecular mechanisms of action of these drugs in diabetes models are also highlighted to understand their antidiabetic mode of action.

Are off-target effects of imatinib the key to improving beta-cell function in diabetes?

The small tyrosine kinase (TK) inhibitor imatinib mesylate (Gleevec, STI571) protects against both type 1 and type 2 diabetes, but as it inhibits many TKs and other proteins, it is not clear by which mechanisms it acts. This present review will focus on the possibility that imatinib acts, at least in part, by improving beta-cell function and survival via off-target effects on beta-cell signaling/metabolic flow events. Particular attention will be given to the possibility that imatinib and other TK inhibitors function as inhibitors of mitochondrial respiration. A better understanding of how imatinib counteracts diabetes will possibly help to clarify the pathogenic role of beta-cell signaling events and mitochondrial function, and hopefully leading to improved treatment of the disease.

Antidiabetic Effects of the Senolytic Agent Dasatinib

OBJECTIVE

To evaluate the antidiabetic effects of the senolytic agent dasatinib in older patients with type 2 diabetes mellitus.

METHODS

This retrospective cohort study included enterprise-wide Mayo Clinic patients using Informatics for Integrating Biology at the Bedside from January 1994 through December 2019. The antidiabetic outcomes (change in hemoglobin A1c value, serum glucose concentration, and diabetic medications) after 1 year of a strongly senolytic tyrosine kinase inhibitor, dasatinib (n=16), was compared with a weakly senolytic tyrosine kinase inhibitor, imatinib (n=32).

RESULTS

Relative to imatinib, patients treated with dasatinib had a mean reduction of 43.7 mg/dL (P=.005) in serum glucose concentration (to convert glucose values to mmol/L, multiply by 0.0555) and required 28.8 fewer total daily insulin units (P=.08) in the setting of a 4.8-kg relative weight loss (5.3% of total body weight; P=.045). Linear regression analysis suggests that the relative difference in weight accounts for 8.4 mg/dL of the 43.7 mg/dL blood glucose value decrease, or 19.2%. Relative to imatinib, patients treated with dasatinib had a mean 0.80 absolute point (P=.05) reduction in hemoglobin A1c and required 18.2 fewer total daily insulin units (P=.16) in the setting of a 5.9-kg relative weight loss (6.3% of total body weight; P=.06).

CONCLUSION

Dasatinib may have antidiabetic effects comparable to contemporary diabetic treatments and may be considered for use as a novel diabetic therapy. Future studies are needed to determine whether these results are translatable to patients with type 2 diabetes mellitus without underlying malignant diseases and to determine whether the antidiabetic effects of dasatinib are due to its senolytic properties.

RIPK2 Dictates Insulin Responses to Tyrosine Kinase Inhibitors in Obese Male Mice

Tyrosine kinase inhibitors (TKIs) used in cancer are also being investigated in diabetes. TKIs can improve blood glucose control in diabetic cancer patients, but the specific kinases that alter blood glucose or insulin are not clear. We sought to define the role of Receptor Interacting Serine/Threonine Kinase 2 (RIPK2) in mouse models of insulin resistance. We tested the TKI gefitinib, which inhibits RIPK2 activity, in wild-type (WT), Nod1-/-, Nod2-/-, and Ripk2-/- mice fed an obesogenic high-fat diet. Gefitinib lowered blood glucose during a glucose tolerance test (GTT) in a nucleotide-binding oligomerization domain (NOD)-RIPK2-independent manner in all obese mice. However, gefitinib lowered glucose-stimulated insulin secretion only in obese Ripk2-/- mice. Gefitinib had no effect on insulin secretion in obese WT, Nod1-/-, or Nod2-/- mice. Hence, genetic deletion of Ripk2 promoted the insulin-sensitizing potential of gefitinib, since this TKI lowered both blood glucose and insulin only in Ripk2-/- mice. Gefitinib did not alter the inflammatory profile of pancreas, adipose, liver, or muscle tissues in obese Ripk2-/- mice compared with obese WT mice. We also tested imatinib, a TKI that does not inhibit RIPK2 activity, in obese WT mice. Imatinib lowered blood glucose during a GTT, consistent with TKIs lowering blood glucose independently of RIPK2. However, imatinib increased glucose-stimulated insulin secretion during the glucose challenge. These data show that multiple TKIs lower blood glucose, where actions of TKIs on RIPK2 dictate divergent insulin responses, independent of tissue inflammation. Our data show that RIPK2 limits the insulin sensitizing effect of gefitinib, whereas imatinib increased insulin secretion.

Dasatinib-induced hypoglycemia in a patient with acute lymphoblastic leukemia

Tyrosine kinase inhibitors can cause significant hypoglycemia in patients with diabetes on other antihyperglycemic medications. These patients should be monitored, and their medications adjusted accordingly.

Adverse effects of dasatinib on glucose-lipid metabolism in patients with chronic myeloid leukaemia in the chronic phase

To explore the differences in glucose-lipid metabolism profiles among the 3 TKIs, we designed a retrospective study to compare the onset of hyperglycaemia, hypertriglyceridemia, hypercholesterolemia and hyper-low density lipoprotein (LDL)-cholesterolemia in the patients with normal baseline glucose-lipid profiles and had no medical record of cardio- or cerebro-vascular diseases and/or metabolic syndrome diseases, and identify variables associated with them. 370 chronic myeloid leukaemia patients receiving dasatinib, nilotinib or imatinib therapy ≥3 months were retrospectively reviewed. During TKI-therapy, the mean fasting glucose, triglyceride, cholesterol, and LDL-cholesterol levels increased significantly in both dasatinib and nilotinib cohorts compared with the imatinib cohort. In multivariate analyses, dasatinib was the factor significantly associated with both poor hyperglycaemia- and hypertriglyceridemia-free survival. In addition, nilotinib was significantly associated with more occurrences of hyperglycaemia and hypercholesterolemia; increasing age was significantly associated with more occurrences of hyperglycaemia and hypertriglyceridemia. We concluded that dasatinib, similar to nilotinib, has the adverse impact on glucose-lipid metabolism compared with imatinib.

Pharmacovigilance evaluation of the relationship between impaired glucose metabolism and BCR-ABL inhibitor use by using an adverse drug event reporting database

Breakpoint cluster region‐Abelson murine leukemia (BCR‐ABL) inhibitors markedly improve the prognosis of chronic myeloid leukemia. However, high treatment adherence is necessary for successful treatment with BCR‐ABL inhibitors. Therefore, an adequate understanding of the adverse event profiles of BCR‐ABL inhibitors is essential. Although many adverse events are observed in trials, an accurate identification of adverse events based only on clinical trial results is difficult because of strict entry criteria or limited follow‐up durations. In particular, BCR‐ABL inhibitor‐induced impaired glucose metabolism remains controversial. Pharmacovigilance evaluations using spontaneous reporting systems are useful for analyzing drug‐related adverse events in clinical settings. Therefore, we conducted signal detection analyses for BCR‐ABL inhibitor‐induced impaired glucose metabolism by using the FDA Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) database. Signals for an increased reporting rate of impaired glucose metabolism were detected only for nilotinib use, whereas these signals were not detected for other BCR‐ABL inhibitors. Subgroup analyses showed a clearly increased nilotinib‐associated reporting rate of impaired glucose metabolism in male and younger patients. Although FAERS‐ and JADER‐based signal detection analyses cannot determine causality perfectly, our study suggests the effects on glucose metabolism are different between BCR‐ABL inhibitors and provides useful information for the selection of appropriate BCR‐ABL inhibitors.

The Salt-Inducible Kinases: Emerging Metabolic Regulators

The discovery of liver kinase B1 (LKB1) as an upstream kinase for AMP-activated protein kinase (AMPK) led to the identification of several related kinases that also rely on LKB1 for their catalytic activity. Among these, the salt-inducible kinases (SIKs) have emerged as key regulators of metabolism. Unlike AMPK, SIKs do not respond to nucleotides, but their function is regulated by extracellular signals, such as hormones, through complex LKB1-independent mechanisms. While AMPK acts on multiple targets, including metabolic enzymes, to maintain cellular ATP levels, SIKs primarily regulate gene expression, by acting on transcriptional regulators, such as the cAMP response element-binding protein-regulated transcription coactivators and class IIa histone deacetylases. This review describes the development of research on SIKs, from their discovery to the most recent findings on metabolic regulation.

Effect of imatinib on plasma glucose concentration in subjects with chronic myeloid leukemia and gastrointestinal stromal tumor

BACKGROUND

Type 2 diabetes mellitus has become one of the most important public health concerns worldwide. Due to its high prevalence and morbidity, there is an avid necessity to find new therapies that slow the progression and promote the regression of the disease. Imatinib mesylate is a tyrosine kinase inhibitor that binds to the Abelson tyrosine kinase and related proteins. It enhances β-cell survival in response to toxins and pro-inflammatory cytokine. The aim of this study is to evaluate the effect of imatinib on fasting plasma glucose in subjects with normal fasting glucose, subjects with impaired fasting glucose and in subjects with type 2 diabetes mellitus.

METHODS

We identified 284 subjects diagnosed with chronic myeloid leukemia or gastrointestinal stromal tumors from the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran database. 106/284 subjects were treated with imatinib. We compared the effect of imatinib on fasting plasma glucose after 1 and 6 months of treatment. We used ANOVA test of repeated samples to determine statistical significance in fasting plasma glucose before imatinib treatment and the follow-up. Statistical analysis was performed with Statistical Package for the Social Sciences v22.

RESULTS

We included a total of 106 subjects: 76 with fasting plasma glucose concentrations < 100 mg/dL (normal FG), 19 subjects with fasting plasma glucose concentrations ≥100 mg/dL (impaired fasting glucose), and 11 subjects with ≥126 mg/dL (type 2 diabetes mellitus). We found a significant increase in fasting plasma glucose concentration in the normal fasting glucose group (p = 0.048), and a significant decrease in fasting plasma glucose concentration in the type 2 diabetes mellitus group (p = 0.042). In the impaired fasting glucose group, we also found a tendency towards a decrease in fasting plasma glucose (p = 0.076). We identified 11 subjects with type 2 diabetes mellitus, of whom, 7 (64%) had a reduction in their fasting plasma glucose concentrations after 6 months. A significant glycosylated hemoglobin reduction (p = 0.04) was observed.

CONCLUSION

Subjects with chronic myeloid leukemia or gastrointestinal stromal tumor with type 2 diabetes mellitus had a significant reduction in fasting plasma glucose and glycosylated hemoglobin at 1 and 6 months while using imatinib.

BCR-ABL Tyrosine Kinase Inhibitors: Which Mechanism(s) May Explain the Risk of Thrombosis?

Imatinib, the first-in-class BCR-ABL tyrosine kinase inhibitor (TKI), had been a revolution for the treatment of chronic myeloid leukemia (CML) and had greatly enhanced patient survival. Second- (dasatinib, nilotinib, and bosutinib) and third-generation (ponatinib) TKIs have been developed to be effective against BCR-ABL mutations making imatinib less effective. However, these treatments have been associated with arterial occlusive events. This review gathers clinical data and experiments about the pathophysiology of these arterial occlusive events with BCR-ABL TKIs. Imatinib is associated with very low rates of thrombosis, suggesting a potentially protecting cardiovascular effect of this treatment in patients with BCR-ABL CML. This protective effect might be mediated by decreased platelet secretion and activation, decreased leukocyte recruitment, and anti-inflammatory or antifibrotic effects. Clinical data have guided mechanistic studies toward alteration of platelet functions and atherosclerosis development, which might be secondary to metabolism impairment. Dasatinib, nilotinib, and ponatinib affect endothelial cells and might induce atherogenesis through increased vascular permeability. Nilotinib also impairs platelet functions and induces hyperglycemia and dyslipidemia that might contribute to atherosclerosis development. Description of the pathophysiology of arterial thrombotic events is necessary to implement risk minimization strategies.

Redox-Dependent Inflammation in Islet Transplantation Rejection

Type 1 diabetes is an autoimmune disease that results in the progressive destruction of insulin-producing pancreatic β-cells inside the islets of Langerhans. The loss of this vital population leaves patients with a lifelong dependency on exogenous insulin and puts them at risk for life-threatening complications. One method being investigated to help restore insulin independence in these patients is islet cell transplantation. However, challenges associated with transplant rejection and islet viability have prevented long-term β-cell function. Redox signaling and the production of reactive oxygen species (ROS) by recipient immune cells and transplanted islets themselves are key players in graft rejection. Therefore, dissipation of ROS generation is a viable intervention that can protect transplanted islets from immune-mediated destruction. Here, we will discuss the newly appreciated role of redox signaling and ROS synthesis during graft rejection as well as new strategies being tested for their efficacy in redox modulation during islet cell transplantation.

Tyrosine kinase inhibitors of Ripk2 attenuate bacterial cell wall-mediated lipolysis, inflammation and dysglycemia

Inflammation underpins aspects of insulin resistance and dysglycemia. Microbiota-derived cell wall components such as muropeptides or endotoxin can trigger changes in host immunity and metabolism. Specific peptidoglycan motifs promote metabolic tissue inflammation, lipolysis and insulin resistance via Nucleotide-binding oligomerization domain-containing protein 1 (Nod1). Receptor-interacting serine/threonine-protein kinase 2 (Ripk2) mediates Nod1-induced immunity, but the role of Ripk2 in metabolism is ill-defined. We hypothesized that Ripk2 was required for Nod1-mediated inflammation, lipolysis and dysglycemia. This is relevant because certain tyrosine kinase inhibitors (TKIs) inhibit Ripk2 and there is clinical evidence of TKIs lowering inflammation and blood glucose. Here, we showed that only a subset of TKIs known to inhibit Ripk2 attenuated Nod1 ligand-mediated adipocyte lipolysis. TKIs that inhibit Ripk2 decreased cytokine responses induced by Nod1-activating peptidoglycan, but not endotoxin in both metabolic and immune cells. Pre-treatment of adipocytes or macrophages with the TKI gefitinib inhibited Nod1-induced Cxcl1 and Il-6 secretion. Furthermore, treatment of mice with gefitinib prevented Nod1-induced glucose intolerance in vivo. Ripk2 was required for these effects on inflammation and metabolism, since Nod1-mediated cytokine and blood glucose changes were absent in Ripk2^−/− mice. Our data show that specific TKIs used in cancer also inhibit Nod1-Ripk2 immunometabolism responses indicative of metabolic disease.

Effects of first- and second-generation tyrosine kinase inhibitor therapy on glucose and lipid metabolism in chronic myeloid leukemia patients: a real clinical problem?

BACKGROUND

Tyrosine kinase inhibitors (TKIs) have dramatically changed the prognosis of patients with chronic myeloid leukemia (CML). They have a distinct toxicity profile that includes glycometabolic alterations: i.e. diabetes mellitus (DM), impaired fasting glucose (IFG), and the metabolic syndrome (MS). The aim of this study was to evaluate the prevalence of these alterations in a cohort of CML-chronic phase patients treated with imatinib, dasatinib or nilotinib.

METHODS

The study involved 168 consecutive CML-chronic phase patients with no history of DM/IFG or MS. Anthropometric and metabolic parameters were assessed, and DM/IFG and MS were diagnosed based on the criteria of the American Diabetes Association and the National Cholesterol Education Program-Adult Treatment Panel III, respectively.

RESULTS

The nilotinib group had significantly higher levels of fasting plasma glucose, insulin, C-peptide, insulin resistance, and total and LDL cholesterol than the imatinib and dasatinib groups. DM/IFG were identified in 25% of the imatinib- and dasatinib-treated patients, and 33% of those in the nilotinib cohort (p = 0.39 vs imatinib and p = 0.69 vs dasatinib). A diagnosis of MS was made in 42.4% of the imatinib-treated patients, 37.5% of the dasatinib-treated patients, and 36.1% of the nilotinib-treated patients (p = 0.46 vs imatinib and p = 0.34 vs dasatinib).

CONCLUSIONS

Treatment with nilotinib does not seem to induce DM/IFG or the MS to a significantly higher extent than imatinib or dasatinib, though it causes a worse glycometabolic profile. These findings suggest the need for a close monitoring of glucose and lipid metabolism and a multidisciplinary approach in patients treated with nilotinib.

European LeukemiaNet recommendations for the management and avoidance of adverse events of treatment in chronic myeloid leukaemia

Most reports on chronic myeloid leukaemia (CML) treatment with tyrosine kinase inhibitors (TKIs) focus on efficacy, particularly on molecular response and outcome. In contrast, adverse events (AEs) are often reported as infrequent, minor, tolerable and manageable, but they are increasingly important as therapy is potentially lifelong and multiple TKIs are available. For this reason, the European LeukemiaNet panel for CML management recommendations presents an exhaustive and critical summary of AEs emerging during CML treatment, to assist their understanding, management and prevention. There are five major conclusions. First, the main purpose of CML treatment is the antileukemic effect. Suboptimal management of AEs must not compromise this first objective. Second, most patients will have AEs, usually early, mostly mild to moderate, and which will resolve spontaneously or are easily controlled by simple means. Third, reduction or interruption of treatment must only be done if optimal management of the AE cannot be accomplished in other ways, and frequent monitoring is needed to detect resolution of the AE as early as possible. Fourth, attention must be given to comorbidities and drug interactions, and to new events unrelated to TKIs that are inevitable during such a prolonged treatment. Fifth, some TKI-related AEs have emerged which were not predicted or detected in earlier studies, maybe because of suboptimal attention to or absence from the preclinical data. Overall, imatinib has demonstrated a good long-term safety profile, though recent findings suggest underestimation of symptom severity by physicians. Second and third generation TKIs have shown higher response rates, but have been associated with unexpected problems, some of which could be irreversible. We hope these recommendations will help to minimise adverse events, and we believe that an optimal management of them will be rewarded by better TKI compliance and thus better CML outcomes, together with better quality of life.

Tyrosine Kinase Inhibitors and Diabetes: A Novel Treatment Paradigm?

Deregulation of protein tyrosine kinase (PTK) activity is implicated in various proliferative conditions. Multi-target tyrosine kinase inhibitors (TKIs) are increasingly used for the treatment of different malignancies. Recently, several clinical cases of the reversal of both type 1 and 2 diabetes mellitus (T1DM, T2DM) during TKI administration have been reported. Experimental in vivo and in vitro studies have elucidated some of the mechanisms behind this effect. For example, inhibition of Abelson tyrosine kinase (c-Abl) results in β cell survival and enhanced insulin secretion, while platelet-derived growth factor receptor (PDGFR) and epidermal growth factor receptor (EGFR) inhibition leads to improvement in insulin sensitivity. In addition, inhibition of vascular endothelial growth factor receptor 2 (VEGFR2) reduces the degree of islet cell inflammation (insulitis). Therefore, targeting several PTKs may provide a novel approach for correcting the pathophysiologic disturbances of diabetes.

The clinically approved drugs dasatinib and bosutinib induce anti-inflammatory macrophages by inhibiting the salt-inducible kinases

Macrophages switch to an anti-inflammatory, ‘regulatory’-like phenotype characterized by the production of high levels of interleukin (IL)-10 and low levels of pro-inflammatory cytokines to promote the resolution of inflammation. A potential therapeutic strategy for the treatment of chronic inflammatory diseases would be to administer drugs that could induce the formation of ‘regulatory’-like macrophages at sites of inflammation. In the present study, we demonstrate that the clinically approved cancer drugs bosutinib and dasatinib induce several hallmark features of ‘regulatory’-like macrophages. Treatment of macrophages with bosutinib or dasatinib elevates the production of IL-10 while suppressing the production of IL-6, IL-12p40 and tumour necrosis factor α (TNFα) in response to Toll-like receptor (TLR) stimulation. Moreover, macrophages treated with bosutinib or dasatinib express higher levels of markers of ‘regulatory’-like macrophages including LIGHT, SPHK1 and arginase 1. Bosutinib and dasatinib were originally developed as inhibitors of the protein tyrosine kinases Bcr-Abl and Src but we show that, surprisingly, the effects of bosutinib and dasatinib on macrophage polarization are the result of the inhibition of the salt-inducible kinases. Consistent with the present finding, bosutinib and dasatinib induce the dephosphorylation of CREB-regulated transcription co-activator 3 (CRTC3) and its nuclear translocation where it induces a cAMP-response-element-binding protein (CREB)-dependent gene transcription programme including that of IL-10. Importantly, these effects of bosutinib and dasatinib on IL-10 gene expression are lost in macrophages expressing a drug-resistant mutant of salt-inducible kinase 2 (SIK2). In conclusion, our study identifies the salt-inducible kinases as major targets of bosutinib and dasatinib that mediate the effects of these drugs on the innate immune system and provides novel mechanistic insights into the anti-inflammatory properties of these drugs.

We have discovered that bosutinib and dasatinib, which are protein tyrosine kinase inhibitors used in the clinic to treat human cancer, induce anti-inflammatory but block pro-inflammatory cytokine production by inhibiting the serine/threonine kinases known as the salt-inducible kinases.

Tyrosine kinase inhibitors as novel drugs for the treatment of diabetes

INTRODUCTION

Some inhibitors of tyrosine kinase, as imatinib, erlotinib and sunitinib have antihyperglycemic effects but the mechanisms are not totally clear.

AREAS COVERED

It is well established that insulin resistance and beta-cell failure are hallmarks of type 2 diabetes mellitus (DM2). The present review will discuss the molecular mechanisms that account for insulin resistance and beta-cell failure in DM2, and also the effect of tyrosine kinase inhibitors in these processes.

EXPERT OPINION

A better understanding of how these drugs improve the two most important mechanisms of DM2 associated with suggestions of clinical studies will lead to improve the treatment of this disease.

Targeted therapy with kinase inhibitors in aggressive endocrine tumors

INTRODUCTION

Kinase inhibitors (KIs) are a class of anticancer drugs that inhibit activity of the enzymes protein kinases, which regulate crucial cellular processes and have a demonstrated role in human oncogenesis. Treatment of advanced forms of endocrine cancer which are not responsive to cytotoxic chemotherapies is challenging and use of KIs is gaining a growing role in this field.

AREAS COVERED

The authors summarize the main genetic alterations known to be linked to endocrine tumors, indicating the rationale for utilizing KIs. Furthermore, they present an updated analysis of clinical trials available on PubMed Central, which were pertinent to the activities of KIs in aggressive endocrine cancer. The authors also discuss the adverse effects of KIs and summarize likely involved underlying mechanisms.

EXPERT OPINION

KIs are effective in obtaining a radiological disease control and an improvement of progression-free survival in several forms of endocrine cancer but will never deliver a knockout blow of the disease, due to mechanisms of adaptation to circumvent the specific molecular blockade. The new frontier of KIs treatment is to identify agents that could synergize activity of KIs. The true goal will be to perform an overall genotyping of each tumor, thus predicting the impact of combined targeted therapies in the context of a particular constellation of mutant genes.

Clinical review: kinase inhibitors: adverse effects related to the endocrine system

CONTEXT

The use of kinase inhibitors (KIs) in the treatment of cancer has become increasingly common, and practitioners must be familiar with endocrine-related side effects associated with these agents. This review provides an update to the clinician regarding the management of potential endocrinological effects of KIs.

EVIDENCE ACQUISITION

PubMed was employed to identify relevant manuscripts. A review of the literature was conducted, and data were summarized and incorporated.

EVIDENCE SYNTHESIS

KIs, including small molecule KIs and monoclonal antibodies directed against kinases, have emerged over the past decade as an important class of anticancer agents. KIs specifically interfere with signaling pathways that are dysregulated in certain types of cancers and also target common mechanisms of growth, invasion, metastasis, and angiogenesis. Currently, at least 20 KIs are approved as cancer therapeutics. However, KIs may affect a broad spectrum of targets and may have additional, unidentified mechanisms of action at the cellular level due to overlap between signaling pathways in the tumor cell and endocrine system. Recent reports in the literature have identified side effects associated with KIs, including alterations in thyroid function, bone metabolism, linear growth, gonadal function, fetal development, adrenal function, and glucose metabolism.

CONCLUSIONS

Clinicians need to monitor the thyroid functions of patients on KIs. In addition, bone density and vitamin D status should be assessed. Special care should be taken to follow linear growth and development in children taking these agents. Clinicians should counsel patients appropriately on the potential adverse effects of KIs on fetal development.

Nilotinib exacerbates diabetes mellitus by decreasing secretion of endogenous insulin

We report a 74-year-old female with chronic myelogenous leukemia (CML) in accelerated phase with pre-existing severe type 2 diabetes (T2D) and hemorrhagic gastric ulcers who was successfully treated with nilotinib. We first considered second-generation tyrosine kinase inhibitors for the treatment of this patient, as they elicit a superior response compared with imatinib. We next selected nilotinib, rather than dasatinib, since the increased risk of bleeding associated with dasatinib represented a greater risk of fatality than aggravation of T2D with nilotinib. After improvement of hemorrhagic gastric ulcers and T2D with exogenous insulin therapy, we began nilotinib administration; insulin dose was increased to maintain her glucose levels whereas urine C-peptide level decreased. Conversely, when nilotinib was discontinued due to liver dysfunction, the dosage of injected insulin was decreased and urine C-peptide levels increased. After re-starting nilotinib, the required dose of insulin gradually increased again, and urine C-peptide level decreased, indicating that nilotinib may have impaired secretion of endogenous insulin. The patient obtained a complete cytogenetic response after 3 months of nilotinib treatment. Her T2D has since been well controlled by insulin therapy. To our knowledge, this is the first report that nilotinib treatment for patients with severe T2D may induce a reversible decrease in endogenous insulin secretion, although the precise underlying mechanisms remain unknown. We highly recommend sufficient screening and early intervention with exogenous insulin therapy for diabetic CML patients who receive nilotinib.

Does the small tyrosine kinase inhibitor Imatinib mesylate counteract diabetes by affecting pancreatic islet amyloidosis and fibrosis?

INTRODUCTION

The small tyrosine kinase inhibitor Imatinib Mesylate (Gleevec) protects against diabetes, but it is not known how.

AREAS COVERED

It has been suggested that islet amyloid and fibrotic deposits promote beta-cell failure and death, leading to Type-2 diabetes. As Imatinib is known to possess anti-fibrotic/amyloid properties, in for example systemic sclerosis and mouse models for Alzheimer's disease, the present review will discuss the possibility that Imatinib acts, at least in part, by ameliorating islet hyalinization and its consequences in the pathogenesis of Type-2 diabetes.

EXPERT OPINION

A better understanding of how Imatinib counteracts Type-2 diabetes will possibly help to clarify the pathogenic role of islet amyloid and fibrosis, and hopefully lead to improved treatment of the disease.

Off-target effects of BCR-ABL1 inhibitors and their potential long-term implications in patients with chronic myeloid leukemia

In patients with chronic myeloid leukemia (CML), use of the BCR-ABL1-specific tyrosine kinase inhibitors (TKIs) imatinib, nilotinib and dasatinib has greatly improved patient survival and prolonged disease remission. More than 10 years of data from imatinib clinical studies and many years of data for nilotinib and dasatinib have demonstrated that these TKIs are well tolerated in most patients with CML. However, these inhibitors are not entirely BCR-ABL1-specific, and this lack of specificity could account for the off-target effects of these drugs. Adverse events (AEs) are off-target effects that are detrimental to the patient. The underlying mechanisms that contribute to these effects are poorly understood and the long-term consequences of chronic TKI therapy remain largely unknown, particularly with the newer agents. Here, we review the preclinical and clinical data for several of the more frequent AEs associated with TKIs and discuss the therapeutic relevance of these AEs for patients with CML.

Targeting of GSK3β promotes imatinib-mediated apoptosis in quiescent CD34+ chronic myeloid leukemia progenitors, preserving normal stem cells

The targeting of BCR-ABL, a hybrid oncogenic tyrosine (Y) kinase, does not eradicate chronic myeloid leukemia (CML)-initiating cells. Activation of β-catenin was linked to CML leukemogenesis and drug resistance through its BCR-ABL-dependent Y phosphorylation and impaired binding to GSK3β (glycogen synthase kinase 3β). Herein, we show that GSK3β is constitutively Y(216) phospho-activated and predominantly relocated to the cytoplasm in primary CML stem/progenitor cells compared with its balanced active/inactive levels and cytosolic/nuclear distribution in normal cells. Under cytokine support, persistent GSK3β activity and its altered subcellular localization were correlated with BCR-ABL-dependent and -independent activation of MAPK and p60-SRC/GSK3β complex formation. Specifically, GSK3β activity and nuclear import were increased by imatinib mesylate (IM), a selective ABL inhibitor, but prevented by dasatinib that targets both BCR-ABL- and cytokine-dependent MAPK/p60-SRC activity. SB216763, a specific GSK3 inhibitor, promoted an almost complete suppression of primary CML stem/progenitor cells when combined with IM, but not dasatinib, while sparing bcr-abl-negative cells. Our data indicate that GSK3 inhibition acts to prime a pro-differentiative/apoptotic transcription program in the nucleus of IM-treated CML cells by affecting the β-catenin, cyclinD1, C-EBPα, ATF5, mTOR, and p27 levels. In conclusion, our data gain new insight in CML biology, indicating that GSK3 inhibitors may be of therapeutic value in selectively targeting leukemia-initiating cells in combination with IM but not dasatinib.

Saturated fatty acids induce c-Src clustering within membrane subdomains, leading to JNK activation

Saturated fatty acids (FA) exert adverse health effects and are more likely to cause insulin resistance and type 2 diabetes than unsaturated FA, some of which exert protective and beneficial effects. Saturated FA, but not unsaturated FA, activate Jun N-terminal kinase (JNK), which has been linked to obesity and insulin resistance in mice and humans. However, it is unknown how saturated and unsaturated FA are discriminated. We now demonstrate that saturated FA activate JNK and inhibit insulin signaling through c-Src activation. FA alter the membrane distribution of c-Src, causing it to partition into intracellular membrane subdomains, where it likely becomes activated. Conversely, unsaturated FA with known beneficial effects on glucose metabolism prevent c-Src membrane partitioning and activation, which are dependent on its myristoylation, and block JNK activation. Consumption of a diabetogenic high-fat diet causes the partitioning and activation of c-Src within detergent insoluble membrane subdomains of murine adipocytes.

Effects of Imatinib Mesylate (Gleevec) on human islet NF-kappaB activation and chemokine production in vitro

Purpose

Imatinib Mesylate (Gleevec) is a drug that potently counteracts diabetes both in humans and in animal models for human diabetes. We have previously reported that this compound in human pancreatic islets stimulates NF-κB signaling and islet cell survival. The aim of this study was to investigate control of NF-κB post-translational modifications exerted by Imatinib and whether any such effects are associated with altered islet gene expression and chemokine production in vitro.

Procedures

Human islets were either left untreated or treated with Imatinib for different timepoints. IκB-α and NF-κB p65 phosphorylation and methylation were assessed by immunoblot analysis. Islet gene expression was assessed using a commercial Pathway Finder microarray kit and RT-PCR. Islet chemokine production was determined by flow cytometric bead array analysis.

Findings

Human islet IκB-α and Ser276-p65 phosphorylation were increased by a 20 minute Imatinib exposure. Methylation of p65 at position Lys221 was increased after 60 min of Imatinib exposure and persisted for 3 hours. Microarray analysis of islets exposed to Imatinib for 4 hours revealed increased expression of the inflammatory genes IL-4R, TCF5, DR5, I-TRAF, I-CAM, HSP27 and IL-8. The islet release of IL-8 was augmented in islets cultured over night in the presence of Imatinib. Following 30 hours of Imatinib exposure, the cytokine-induced IκB-α and STAT1 phosphorylation was abolished and diminished, respectively. The cytokine-induced release of the chemokines MIG and IP10 was lower in islets exposed to Imatinib for 30 hours.

Conclusion

Imatinib by itself promotes a modest activation of NF-κB. However, a prolonged exposure of human islets to Imatinib is associated with a dampened response to cytokines. It is possible that Imatinib induces NF-κB preconditioning of islet cells leading to lowered cytokine sensitivity and a mitigated islet inflammation.

Effect of the tyrosine kinase inhibitors (sunitinib, sorafenib, dasatinib, and imatinib) on blood glucose levels in diabetic and nondiabetic patients in general clinical practice

Tyrosine kinase is a key enzyme activity utilized in many intracellular messaging pathways. Understanding the role of particular tyrosine kinases in malignancies has allowed for the design of tyrosine kinase inhibitors (TKIs), which can target these enzymes and interfere with downstream signaling. TKIs have proven to be successful in the treatment of chronic myeloid leukemia, renal cell carcinoma and gastrointestinal stromal tumor, and other malignancies. Scattered reports have suggested that these agents appear to affect blood glucose (BG). We retrospectively studied the BG concentrations in diabetic (17) and nondiabetic (61) patients treated with dasatinib (8), imatinib (39), sorafenib (23), and sunitinib (30) in our clinical practice. Mean declines of BG were dasatinib (53 mg/dL), imatinib (9 mg/dL), sorafenib (12 mg/dL), and sunitinib (14 mg/dL). All these declines in BG were statistically significant. Of note, 47% (8/17) of the patients with diabetes were able to discontinue their medications, including insulin in some patients. Only one diabetic patient developed symptomatic hypoglycemia while on sunitinib. The mechanism for the hypoglycemic effect of these drugs is unclear, but of the four agents tested, c-kit and PDGFRβ are the common target kinases. Clinicians should keep the potential hypoglycemic effects of these agents in mind; modification of hypoglycemic agents may be required in diabetic patients. These results also suggest that inhibition of a tyrosine kinase, be it c-kit, PDGFRβ or some other undefined target, may improve diabetes mellitus BG control and it deserves further study as a potential novel therapeutic option.

Potential utility of small tyrosine kinase inhibitors in the treatment of diabetes

Altered tyrosine kinase signalling has been implicated in several diseases, paving the way for the development of small-molecule TKIs (tyrosine kinase inhibitors). TKIs such as imatinib, sunitinib and dasatinib are clinically used for treating chronic myeloid leukaemia, gastrointestinal stromal tumours and other malignancies. In addition to their use as anti-cancer agents, increasing evidence points towards an anti-diabetic effect of these TKIs. Imatinib and other TKIs counteract diabetes not only in non-obese diabetic mice, but also in streptozotocin diabetic mice, db/db mice, high-fat-treated rats and humans with T2D (Type 2 diabetes). Although the mechanisms of protection need to be investigated further, the effects of imatinib and other TKIs in human T2D and the rapidly growing findings from animal models of T1D (Type 1 diabetes) and T2D are encouraging and give hope to improved treatment of human diabetes. In the present article, we review the anti-diabetic effects of TKIs which appear to involve both protection against beta-cell death and improved insulin sensitivity. Considering the relatively mild side effects of TKIs, we hypothesize that TKIs could be used to treat new-onset T1D, prevent T1D in individuals at high risk of developing the disease, treat the late stages of T2D and improve the outcome of islet transplantation.

Abnormalities in glucose uptake and metabolism in imatinib-resistant human BCR-ABL-positive cells

The development of imatinib resistance has become a significant therapeutic problem in which the etiology seems to be multifactorial and poorly understood. As of today, clinical criteria to predict the development of imatinib resistance in chronic myelogenous leukemia (CML), other than rebound of the myeloproliferation, are under development. However, there is evidence that the control of glucose-substrate flux is an important mechanism of the antiproliferative action of imatinib because imatinib-resistant gastrointestinal stromal KIT-positive tumors reveal highly elevated glucose uptake in radiologic images. We used nuclear magnetic resonance spectroscopy and gas chromatography mass spectrometry to assess (13)C glucose uptake and metabolism (glycolysis, TCA cycle, and nucleic acid ribose synthesis) during imatinib treatment in CML cell lines with different sensitivities to imatinib. Our results show that sensitive K562-s and LAMA84-s BCR-ABL-positive cells have decreased glucose uptake, decreased lactate production, and an improved oxidative TCA cycle following imatinib treatment. The resistant K562-r and LAMA84-r cells maintained a highly glycolytic metabolic phenotype with elevated glucose uptake and lactate production. In addition, oxidative synthesis of RNA ribose from (13)C-glucose via glucose-6-phosphate dehydrogenase was decreased, and RNA synthesis via the nonoxidative transketolase pathway was increased in imatinib-resistant cells. CML cells which exhibited a (oxidative/nonoxidative) flux ratio for nucleic acid ribose synthesis of >1 were sensitive to imatinib. The resistant K562-r and LAMA84-r exhibited a (oxidative/nonoxidative) flux ratio of <0.7. The changes in glucose uptake and metabolism were accompanied by intracellular translocation of GLUT-1 from the plasma membrane into the intracellular fraction in sensitive cells treated with imatinib, whereas GLUT-1 remained located at the plasma membrane in LAMA84-r and K562-r cells. The total protein load of GLUT-1 was unchanged among treated sensitive and resistant cell lines. In summary, elevated glucose uptake and nonoxidative glycolytic metabolic phenotype can be used as sensitive markers for early detection of imatinib resistance in BCR-ABL-positive cells.