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.

The tyrosine kinase inhibitor crizotinib influences blood glucose and mRNA expression of GLUT4 and PPARs in the heart of rats with experimental diabetes

Tyrosine kinases inhibitors (TKIs) may alter glycaemia and may be cardiotoxic with importance in the diabetic heart. We investigated the effect of multi-TKI crizotinib after short-term administration on metabolic modulators of the heart of diabetic rats. Experimental diabetes mellitus (DM) was induced by streptozotocin (STZ; 80 mg·kg^-1, i.p.), and controls (C) received vehicle. Three days after STZ, crizotinib (STZ+CRI; 25 mg·kg^-1 per day p.o.) or vehicle was administered for 7 days. Blood glucose, C-peptide, and glucagon were assessed in plasma samples. Receptor tyrosine kinases (RTKs), cardiac glucose transporters, and peroxisome proliferator-activated receptors (PPARs) were determined in rat left ventricle by RT-qPCR method. Crizotinib moderately reduced blood glucose (by 25%, P < 0.05) when compared to STZ rats. The drug did not affect levels of C-peptide, an indicator of insulin secretion, suggesting altered tissue glucose utilization. Crizotinib had no impact on cardiac RTKs. However, an mRNA downregulation of insulin-dependent glucose transporter Glut4 in the hearts of STZ rats was attenuated after crizotinib treatment. Moreover, crizotinib normalized Ppard and reduced Pparg mRNA expression in diabetic hearts. Crizotinib decreased blood glucose independently of insulin and glucagon. This could be related to changes in regulators of cardiac metabolism such as GLUT4 and PPARs.

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.

Role of Epidermal Growth Factor Receptor (EGFR) and Its Ligands in Kidney Inflammation and Damage

Chronic kidney disease (CKD) is characterized by persistent inflammation and progressive fibrosis, ultimately leading to end-stage renal disease. Although many studies have investigated the factors involved in the progressive deterioration of renal function, current therapeutic strategies only delay disease progression, leaving an unmet need for effective therapeutic interventions that target the cause behind the inflammatory process and could slow down or reverse the development and progression of CKD. Epidermal growth factor receptor (EGFR) (ERBB1), a membrane tyrosine kinase receptor expressed in the kidney, is activated after renal damage, and preclinical studies have evidenced its potential as a therapeutic target in CKD therapy. To date, seven official EGFR ligands have been described, including epidermal growth factor (EGF) (canonical ligand), transforming growth factor-α, heparin-binding epidermal growth factor, amphiregulin, betacellulin, epiregulin, and epigen. Recently, the connective tissue growth factor (CTGF/CCN2) has been described as a novel EGFR ligand. The direct activation of EGFR by its ligands can exert different cellular responses, depending on the specific ligand, tissue, and pathological condition. Among all EGFR ligands, CTGF/CCN2 is of special relevance in CKD. This growth factor, by binding to EGFR and downstream signaling pathway activation, regulates renal inflammation, cell growth, and fibrosis. EGFR can also be “transactivated” by extracellular stimuli, including several key factors involved in renal disease, such as angiotensin II, transforming growth factor beta (TGFB), and other cytokines, including members of the tumor necrosis factor superfamily, showing another important mechanism involved in renal pathology. The aim of this review is to summarize the contribution of EGFR pathway activation in experimental kidney damage, with special attention to the regulation of the inflammatory response and the role of some EGFR ligands in this process. Better insights in EGFR signaling in renal disease could improve our current knowledge of renal pathology contributing to therapeutic strategies for CKD development and progression.

KIT as a therapeutic target for non-oncological diseases

KIT is a receptor tyrosine kinase that after binding to its ligand stem cell factor activates signaling cascades linked to biological processes such as proliferation, differentiation, migration and cell survival. Based on studies performed on SCF and/or KIT mutant animals that presented anemia, sterility, and/or pigmentation disorders, KIT signaling was mainly considered to be involved in the regulation of hematopoiesis, gametogenesis, and melanogenesis. More recently, novel animal models and ameliorated cellular and molecular techniques have led to the discovery of a widen repertoire of tissue compartments and functions that are being modulated by KIT. This is the case for the lung, heart, nervous system, gastrointestinal tract, pancreas, kidney, liver, and bone. For this reason, the tyrosine kinase inhibitors that were originally developed for the treatment of hemato-oncological diseases are being currently investigated for the treatment of non-oncological disorders such as asthma, rheumatoid arthritis, and alzheimer's disease, among others. The beneficial effects of some of these tyrosine kinase inhibitors have been proven to depend on KIT inhibition. This review will focus on KIT expression and regulation in healthy and pathologic conditions other than cancer. Moreover, advances in the development of anti-KIT therapies, including tyrosine kinase inhibitors, and their application will be discussed.

Toxicity of Cancer Therapies in Older Patients

PURPOSE OF THE REVIEW

In clinical practice, older patients are often undertreated due to underrepresentation in clinical trials and fear of toxicity. Our objective was therefore to review toxicities that are specific to older cancer patients, to review risk factors in order to help physicians guide their decisions, and to review interventions that can be implemented in routine clinical practice to prevent toxicity induced by cancer therapies.

RECENT FINDINGS

On the whole, reviews report similar number and frequency as well as similar grade 3 or 4 adverse events between subjects older and younger than 65 years. Yet patients included in clinical trials are often not representative of real-life patients and are often fit older cancer patients. Moreover, tolerance to the additive impact of multiple adverse effects is different between older and younger patients. And specific symptoms such as stomatitis may cause a series of consequences such as dehydration, denutrition, renal insufficiency, and adverse events of renally excreted drugs. Older patients are at high risk of toxicity due to many factors but mainly due to the prevalence of frailty in this population that has been estimated to be around 40% increasing the risk of chemotherapy intolerance. As a consequence, interventions must be implemented according to altered domains of comprehensive geriatric assessment in order to improve anticancer tolerance. These interventions are reviewed here.

Sunitinib specifically augments glucose-induced insulin secretion

The tyrosine kinase inhibitor sunitinib is used for the treatment of numerous cancers in humans. In diabetic patients, sunitinib lowers blood glucose levels and improves glycaemic control. This study aims to analyse whether sunitinib has specific and direct effects on insulin secreting β-cells. Regulation of insulin secretion, of cellular cAMP levels and activation of signalling pathways were examined upon exposure of rat insulinoma INS-1E cells to sunitinib under specific stimulatory and inhibitory conditions. Secreted insulin and cellular cAMP levels were measured using RIA and ELISA, respectively. Protein phosphorylations were examined on western blots. Sunitinib enhanced glucose-induced insulin secretion (GIIS) concentration-dependently, reaching a maximal stimulation at 2μM. Sunitinib further augmented insulin secretion in the presence of elevated cAMP levels and the FFAR1 agonists. Adrenaline and the PKA inhibitor H89 counteracted the stimulatory effect of sunitinib on secretion. However, sunitinib altered neither the cellular levels of cAMP nor the phosphorylation of PKA. Sunitinib did not reduce IGF-1-induced phosphorylation of AKT/PKB and ERK1/2. In conclusion, these results suggest that sunitinib stimulates GIIS by a direct effect on β-cells, which may contribute to the glucose-lowering action of the tyrosine kinase inhibitor in humans.

Novel EGFR inhibitors attenuate cardiac hypertrophy induced by angiotensin II

Cardiac hypertrophy is an important risk factor for heart failure. Epidermal growth factor receptor (EGFR) has been found to play a role in the pathogenesis of various cardiovascular diseases. The aim of this current study was to examine the role of EGFR in angiotensin II (Ang II)-induced cardiac hypertrophy and identify the underlying molecular mechanisms. In this study, we observed that both Ang II and EGF could increase the phospohorylation of EGFR and protein kinase B (AKT)/extracellular signal-regulated kinase (ERK), and then induce cell hypertrophy in H9c2 cells. Both pharmacological inhibitors and genetic silencing significantly reduced Ang II-induced EGFR signalling pathway activation, hypertrophic marker overexpression, and cell hypertrophy. In addition, our results showed that Ang II-induced EGFR activation is mediated by c-Src phosphorylation. In vivo, Ang II treatment significantly led to cardiac remodelling including cardiac hypertrophy, disorganization and fibrosis, accompanied by the activation of EGFR signalling pathway in the heart tissues, while all these molecular and pathological alterations were attenuated by the oral administration with EGFR inhibitors. In conclusion, the c-Src-dependent EGFR activation may play an important role in Ang II-induced cardiac hypertrophy, and inhibition of EGFR by specific molecules may be an effective strategy for the treatment of Ang II-associated cardiac diseases.

The early effect of sunitinib on insulin clearance in patients with metastatic renal cell carcinoma

AIMS

In patients with diabetes treated with sunitinib symptomatic hypoglycaemia has been reported. To explore the mechanism of this adverse effect we performed a prospective study to investigate the effect of sunitinib on insulin concentration, insulin clearance and insulin sensitivity.

METHODS

We studied the early effects of sunitinib on insulin sensitivity and insulin clearance with a hyperinsulinaemic euglycaemic clamp (insulin infusion rate 60 mU m−2 min−1; steady-state 90–120 min) in patients with renal cell carcinoma before and 1 week after the start of sunitinib 50 mg day−1. Insulin sensitivity index (SI) was defined as steady-state glucose disposal divided by the steady-state plasma insulin.

RESULTS

Ten patients (one with diabetes, treated with metformin) were included in the study protocol. Steady-state insulin concentrations during the clamp increased after 1 week of sunitinib (from 128.9 ± 9.0 mU l−1 to 170.8 ± 12.8 mU l−1, P < 0.05; 95% CI on difference − 64.3, −19.6). The calculated insulin sensitivity index decreased from 0.22 ± 0.04 before to 0.18 ± 0.02 μmol kg−1 min−1 per mU l−1 insulin (P < 0.05; 95% CI on difference 0.07, 0.08). As the insulin infusion rate was similar for both clamps, the increased steady-state insulin concentration indicates reduced insulin clearance.

CONCLUSION

Sunitinib affects insulin clearance which could possibly lead to overexposure to insulin in patients using insulin or insulin-secretion stimulating agents.

Vascular and Metabolic Implications of Novel Targeted Cancer Therapies: Focus on Kinase Inhibitors

Novel targeted cancer therapies, especially kinase inhibitors, have revolutionized the treatment of many cancers and have dramatically improved the survival of several types of malignancies. Because kinases not only are important in cancer development and progression, but also play a critical role in the cardiovascular (CV) system and metabolic homeostasis, important CV and metabolic sequelae have been associated with several types of kinase inhibitors. This paper reviews the incidences and highlights potential mechanisms of vascular and metabolic perturbations associated with 3 classes of commonly used kinase inhibitors that target the vascular endothelial growth factor signaling pathway, the ABL kinase, and the phosphoinositide 3-kinase/AKT/mammalian target of rapamycin signaling pathway. We propose preventive, screening, monitoring, and management strategies for CV care of patients treated with these novel agents.

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.

Metabolic disorders associated with the use of targeted cancer therapies

PURPOSE OF REVIEW

The everyday use of targeted therapies, whose mechanisms of action differ from the conventional cytotoxic agents, also causes the emergence of new toxicities as metabolic disorders about which little is known. We propose a systematic literature review of the incidence and physiopathology of targeted therapies-induced metabolic disorders and provide some management guidance.

RECENT FINDINGS

In recent decades, significant breakthroughs in molecular oncology and immunology have been made. The administration of targeted therapies and immunotherapy has been associated with metabolic toxicities such as endocrine disorders, dyslipidemia, induced diabetes, and electrolytic disorders. Current data show that metabolic disorders are becoming increasingly common, but rarely life threatening and often reversible with prompt therapeutic intervention.

SUMMARY

In the era of targeted therapies, medical oncologists should know the symptoms, carefully monitor patients for potential metabolic disorders, and manage these emerging side-effects with the help of endocrinologists and other medical specialists.

A PKM2 signature in the failing heart

A salient feature of the failing heart is metabolic remodeling towards predominant glucose metabolism and activation of the fetal gene program. Sunitinib is a multitargeted receptor tyrosine kinase inhibitor used for the treatment of highly vascularized tumors. In diabetic patients, sunitinib significantly decreases blood glucose. However, a considerable proportion of sunitinib-treated patients develop cardiac dysfunction or failure. We asked whether sunitinib treatment results in shift towards glycolysis in the heart. Glucose uptake by the heart was increased fivefold in mice treated with sunitinib. Transcript analysis by qPCR revealed an induction of genes associated with glycolysis and reactivation of the fetal gene program. Additionally, we observed a shift in the enzyme pyruvate kinase from the adult M1 (PKM1) isoform to the fetal M2 (PKM2) isoform, a hallmark of the Warburg Effect. This novel observation led us to examine whether a similar shift occurs in human heart failure. Examination of tissue from patients with heart failure similarly displayed an induction of PKM2. Moreover, this phenomenon was partially reversed following mechanical unloading. We propose that pyruvate kinase isoform switching represents a novel feature of the fetal gene program in the failing heart.

Sunitinib and improved diabetes control

There is increasing use of tyrosine kinase inhibitors as targeted therapy for several malignancies. Sunitinib is the first-line treatment for renal cancer and we report a case of a man receiving this medication who also had diabetes. When started on sunitinib he experienced improvement in his diabetes control with reduction in his insulin requirements, which later worsened when sunitinib was reduced or stopped. Several retrospective studies have been performed demonstrating this effect with sunitinib, but to date no prospective studies have been reported. Most tyrosine kinase inhibitors reduce blood glucose levels in diabetics, but some agents, such as nilotinib, may increase them. There is no consensus on the mechanism of action of sunitinib in reducing glucose levels. Several theories have been postulated, such as increased insulin secretion, increased insulin sensitivity, reduced loss of islet cells, the gastrointestinal side effects of sunitinib, or an interaction with other antihyperglycaemic agents.

Role of epidermal growth factor receptor in vascular structure and function

PURPOSE OF THE REVIEW

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase with a wide implication in tumor biology, wound healing and development. Besides acting as a growth factor receptor activated by ligands such as EGF, the EGFR can also be transactivated and thereby mediate cross-talk with different signaling pathways. The aim of this review is to illustrate the Janus-faced function of the EGFR in the vasculature with its relevance for vascular biology and disease.

RECENT FINDINGS

Over recent years, the number of identified signaling partners of the EGFR has steadily increased, as have the biological processes in which the EGFR is thought to be involved. Recently, new models have allowed investigation of EGFR effects in vivo, shedding some light on the overall function of the EGFR in the vasculature. At the same time, EGFR inhibitors and antibodies have become increasingly established in cancer therapy, providing potential therapeutic tools for decreasing EGFR signaling.

SUMMARY

The EGFR is a versatile signaling pathway integrator associated with vascular homeostasis and disease. In addition to modulating basal vascular tone and tissue homeostasis, the EGFR also seems to be involved in proinflammatory, proliferative, migratory and remodeling processes, with enhanced deposition of extracellular matrix components, thereby promoting vascular diseases such as hypertension or atherosclerosis.

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.

Metastatic renal cell carcinoma: how to make the best sequencing decision after withdrawal for intolerance to a tyrosine kinase inhibitor

With seven agents approved for metastatic renal cell carcinoma (RCC) within the past few years, there has undoubtedly been progress in treating this disease. The treatment safety of these new agents, however, now represents a crucial concern, which requires a search for the best possible balance between the minimization of the treatment burden and the need for maintaining appropriate drug dosages able to induce the best clinical benefit. In this review we have analyzed safety data of all approved targeted agents for metastatic RCC available as first- or second-line therapy to provide suggestions aimed at establishing the most appropriate second-line or later treatment on the basis of toxicities that have arisen in therapy. Based on the characteristics and comorbidities of the patients and on the toxicity profile of each treatment, it is possible to plan different therapeutic options. We, therefore, have compiled a list of points that are important to keep in mind when considering the use of the targeted drugs for the treatment of advanced RCC.

Sunitinib-induced severe hypoglycemia in a diabetic patient

Introduction:

Sunitinib is an oral inhibitor of tyrosine kinase that was used for the treatment of mRCC. The general side effects are fatigue, asthenia, diarrhea, mucositis, nausea, vomiting, skin changes, hypertension, hypothyroidism and hematologic side effects. In addition, sunitinib-induced hypoglycemia has also been reported. There are limited number of case reports related to sunitinib-induced hypoglycemia.

Case presentation:

In this case report, we have presented a patient with type 2 diabetes mellitus (DM) with emerging severe hypoglycemia after sunitinib treatment. It was shown that blood glucose levels were normalized two weeks after the interruption of sunitinib.

Conclusion:

Although the underlying mechanism of sunitinib-induced hypoglycemia is not completely understood, sunitinib can be regarded to have an antidiabetic effect. In the literature, there are some reports about sunitinib/other TKI induced hypoglycemia; however, life threatening hypoglycemia is rare. There is no case report of severe hypoglycemia due to imatinib; however, there are two case reports with severe hypoglycemia due to sunitinib treatment. Symptomatic hypoglycemic episodes due to sunitinib may lead to hospital admission. Diabetic patients may develop severe hypoglycaemia and it should be kept in mind that the discontinuation of antihyperglycemic treatment may be required. Therefore, blood glucose levels should be closely monitored in diabetic patients with mRCC during sunitinib therapy.

The use of targeted therapies in pancreatic neuroendocrine tumours: patient assessment, treatment administration, and management of adverse events

Together with the use of novel oral targeted therapies, a multidisciplinary approach can be used to effectively treat patients with advanced pancreatic neuroendocrine tumours (pNETs). Here we review the integration of the oncology nurse to the newly developed oral treatment setting for patients with pNETs. From the outset, the nurse must be involved in various processes, including performance of baseline assessments (e.g. blood pathology, cardiac and lung function testing, patient history) and general medical observations, treatment administration, dietary guidance, evaluation of comorbidities, and review of concomitant medications. Patient education and establishment of a strong partnership in care before the start of pNET therapy ultimately increase treatment adherence and reduce potential toxicities. Regular review of general patient status and disease progression and continuous monitoring of adverse events also help enhance treatment outcomes and subsequently improve quality of life. Nurses' knowledge of agent-specific toxicities and prompt, proactive management is a critical aspect of care. In essence, as the pNET treatment landscape evolves, the role of the healthcare professional in overall patient care must shift accordingly.

Lost in translation: endoplasmic reticulum stress and the decline of β-cell health in diabetes mellitus

Emerging data illustrate a pivotal role for activation of β-cell endoplasmic reticulum (ER) stress pathways in diabetes pathophysiology. The purpose of this review is to appraise the evidence for β-cell ER stress in human type 1 and 2 diabetes, review the molecular signalling pathways involved in the unfolded protein response and ER stress signalling, and to provide data from polyribosome profiling to illustrate the impact of ER stress on the mRNA translation response. Finally, we will discuss existing and novel therapeutic strategies that target β-cell ER stress and discuss their use in rodent and human type 1 and 2 diabetes.

Transformation of nonfunctioning pancreatic neuroendocrine carcinoma cells into insulin producing cells after treatment with sunitinib

We report a rare case of severe hypoglycemia after sunitinib treatment for pancreatic neuroendocrine carcinoma. We describe the initial clinical presentation, laboratory results, pathologic findings, and managment in a patient with a nonfunctioning pancreatic neuroendocrine carcinoma with liver metastases who developed life threatening hypoglycemia after 2 months of sunitinib therapy. A 46-year-old woman presented to the emergency department with loss of consciousness from hypoglycemia. Serum C-peptide and insulin levels at fasting state revealed that the hypoglycemia resulted from endogenous hyperinsulinemia. She had been diagnosed with nonfunctioning pancreatic neuroendocrine carcinoma based on a biopsy of metastatic cervical lymph node and was being treated with sunitinib, a small molecule tyrosine kinase inhibitor. Immunohistochemical stain of the metastatic liver mass demonstrated that the initially nonfunctioning neuroendocrine carcinoma cells had changed into insulin-producing cells after sunitinib therapy. Transarterial chemoembolization of the liver masses and systemic chemotherapy with streptozotocin/adriamycin relieved the hypoglycemia. A nonfunctioning pancreatic neuroendocrine carcinoma was transformed into an insulin-producing tumor after treatment with sunitinib, causing endogenous hyperinsulinemia and severe hypoglycemia.

Imatinib mesilate-induced phosphatidylinositol 3-kinase signalling and improved survival in insulin-producing cells: role of Src homology 2-containing inositol 5'-phosphatase interaction with c-Abl

AIMS/HYPOTHESIS

It is not clear how small tyrosine kinase inhibitors, such as imatinib mesilate, protect against diabetes and beta cell death. The aim of this study was to determine whether imatinib, as compared with the non-cAbl-inhibitor sunitinib, affects pro-survival signalling events in the phosphatidylinositol 3-kinase (PI3K) pathway.

METHODS

Human EndoC-βH1 cells, murine beta TC-6 cells and human pancreatic islets were used for immunoblot analysis of insulin receptor substrate (IRS)-1, Akt and extracellular signal-regulated kinase (ERK) phosphorylation. Phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] plasma membrane concentrations were assessed in EndoC-βH1 and MIN6 cells using evanescent wave microscopy. Src homology 2-containing inositol 5'-phosphatase 2 (SHIP2) tyrosine phosphorylation and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) serine phosphorylation, as well as c-Abl co-localisation with SHIP2, were studied in HEK293 and EndoC-βH1 cells by immunoprecipitation and immunoblot analysis. Gene expression was assessed using RT-PCR. Cell viability was measured using vital staining.

RESULTS

Imatinib stimulated ERK(thr202/tyr204) phosphorylation in a c-Abl-dependent manner. Imatinib, but not sunitinib, also stimulated IRS-1(tyr612), Akt(ser473) and Akt(thr308) phosphorylation. This effect was paralleled by oscillatory bursts in plasma membrane PI(3,4,5)P3 levels. Wortmannin induced a decrease in PI(3,4,5)P3 levels, which was slower in imatinib-treated cells than in control cells, indicating an effect on PI(3,4,5)P3-degrading enzymes. In line with this, imatinib decreased the phosphorylation of SHIP2 but not of PTEN. c-Abl co-immunoprecipitated with SHIP2 and its binding to SHIP2 was largely reduced by imatinib but not by sunitinib. Imatinib increased total β-catenin levels and cell viability, whereas sunitinib exerted negative effects on cell viability.

CONCLUSIONS/INTERPRETATION

Imatinib inhibition of c-Abl in beta cells decreases SHIP2 activity, which results in enhanced signalling downstream of PI3 kinase.

Therapeutic effect of sunitinib malate and its influence on blood glucose concentrations in a patient with metastatic insulinoma

Standard cytotoxic chemotherapy has limited efficacy in advanced insulinomas, and control of blood glucose concentrations in these patients may be difficult. This article describes an elderly (74-year-old) man with metastatic insulinoma and severe hypoglycemia who was treated with repeated 6-week cycles of oral sunitinib malate (25 mg/day for 4 weeks, followed by 2 weeks off treatment). After treatment for more than 2 years, his condition improved and he continued to have a good quality of life with no evidence of tumor progression based on PET/CT findings. Although sunitinib treatment lowered the patient's blood glucose concentrations further and induced repeated symptomatic hypoglycemic episodes, he was able to tolerate the treatment well after changing the timing of sunitinib dosing and adjusting his diet.

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.

Safety and activity of sunitinib in elderly patients (≥ 70 years) with metastatic renal cell carcinoma: a multicenter study

BACKGROUND

Actual tolerability of sunitinib is still poorly documented in elderly patients with metastatic renal cell carcinoma (mRCC).

PATIENTS AND METHODS

Charts of elderly patients treated with sunitinib for mRCC were reviewed in six Italian centers to assess safety (primary objective), efficacy and correlation of toxicity with comprehensive geriatric assessment (CGA) (secondary objectives).

RESULTS

Sixty-eight patients were eligible, and the median age was 74 years. CGA was carried out in 34 patients (41% fit, 41% vulnerable and 18.5% frail). The dose reduction to 37.5 mg was made upfront or soon after the first cycle in 69.1%. More frequent toxic effects were fatigue (80.9%), mucositis (61.8%) and hypertension (58.8%). Cardiac events occurred in nine patients. In 10 patients, therapy was interrupted early due to rapidly progressive disease (10.3%) or severe toxicity (4.4%: 1 cardiac failure, 1 fatigue, 1 febrile neutropenia). At a median follow-up of 27.1 months, the median OS was 18.3 months and the median PFS was 13.6 months. Correlation was not found between frailty at CGA with severe toxicity nor with response.

CONCLUSIONS

Treatment with sunitinib is effective in elderly patients; yet early interruptions were frequent. Starting treatment at reduced dose and escalating in the absence of severe toxicity could be suggested.

The effect of sorafenib treatment on the diabetic status of patients with renal cell or hepatocellular carcinoma

AIM

To evaluate the effect of sorafenib on the glucose tolerance and diabetic status of patients with metastatic renal cell carcinoma (RCC) or advanced hepatocellular carcinoma (HCC).

MATERIALS & METHODS

Eighty patients with metastatic RCC or advanced HCC received 400 mg sorafenib twice daily for an average of approximately 8 and 5 months, respectively; 22 had diabetes mellitus and three had prediabetes.

RESULTS

One of 55 nondiabetic patients, and one of three patients with impaired fasting glucose or impaired glucose tolerance developed diabetes mellitus, one of 12 patients on oral antihyperglycemic agents switched to insulin and no patient treated with insulin needed to increase their dose.

CONCLUSION

Sorafenib has the potential to be a feasible and safe treatment option for patients with advanced HCC or metastatic RCC and comorbid diabetes mellitus or prediabetes.

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.

[Anti-angiogenic agents in the treatment of lung cancer: indications and toxicities]

Lung cancer is the leading cause of cancer-related death. Targeting the vascular endothelial growth factor (VEGF) pathways in combination with standard chemotherapy can improve response rate and survival in non-small cell lung cancer. Since October 2006, a new class of drugs targeting angiogenesis has been introduced for the treatment of advanced lung cancer. Bevacizumab, an antibody directly targeting VEGF was the first agent to be approved. Other small molecule tyrosine kinase inhibitors targeting the VEGF receptor are also active in the treatment of advanced lung cancer and are currently under development. Most of these new drugs are well tolerated though potentially significant toxicities such as haemoptysis and hypertension have been observed. This article will review these new-targeted anti-angiogenic agents with a focus on their use in lung cancer and on their important side effects.

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.

Life-threatening hypoglycemia induced by a tyrosine kinase inhibitor in a patient with neuroendocrine tumor: a case report

We describe a case of a patient who was confronted with two life-threatening conditions: extensive neuroendocrine tumor and hypoglycemia induced by sunitinib administration, as an anti-neoplastic agent. Administration of small dose of prednisolone could prevent severe hypoglycemia and improve glucose homeostasis.

Restoring endoplasmic reticulum function by chemical chaperones: an emerging therapeutic approach for metabolic diseases

The endoplasmic reticulum (ER) is a eukaryotic organelle that plays important roles in protein synthesis, folding and trafficking, calcium homoeostasis and lipid and steroid synthesis. It is the major protein synthesis compartment for secreted, plasma membrane and organelle proteins. Perturbations of ER homeostasis such as the accumulation of unfolded or misfolded proteins cause ER stress. To alleviate this stress, ER triggers an evolutionarily conserved signalling cascade called the unfolded protein response (UPR). As an initial response, the UPR aims at adapting and restoring ER function by translational attenuation, upregulation of ER chaperones and degradation of unfolded proteins. However, if the ER function is severely impaired because of excessive or prolonged exposure to stress, then the inflicted cells may undergo programmed cell death. During ER stress, unstable or partially folded mutant proteins are prevented from trafficking to their proper subcellular localizations and usually rapidly degraded. The small molecules named chemical chaperones help to stabilize these mutant proteins and facilitate their folding and proper trafficking from the ER to their final destinations. Because increasing number of studies suggest that ER stress is involved in a number of disease pathogenesis including neurodegenerative diseases, cancer, obesity, diabetes and atherosclerosis, promoting ER folding capacity through chemical chaperones emerges as a novel therapeutic approach. In this review, we provide insight into the many important functions of chemical chaperones during ER stress, their impact on the ER-stress-related pathologies and their potential as a new drug targets, especially in the context of metabolic disorders.

Practical management of tyrosine kinase inhibitor-associated side effects in GIST

Patients diagnosed with advanced gastrointestinal stromal tumor (GIST) are currently treated with oral tyrosine kinase inhibitors (TKIs). Imatinib mesylate is the standard first-line treatment, and sunitinib malate is administered second-line for patients who are intolerant or progress on imatinib. Imatinib has recently been approved for adjuvant treatment of GIST patients who have a significant risk for relapse. In both the metastatic and adjuvant settings, patients may be on these TKIs for many years. Low plasma imatinib levels have been reported to be associated with a short median time to progression of advanced GIST, stressing the importance of maintaining optimal drug levels. We summarize management of the most frequent and clinically significant adverse effects of imatinib and sunitinib in the treatment of GIST in the context of current guidelines, published literature, and the experience of three large GIST referral centers. The adverse events reviewed include nausea and vomiting, diarrhea, skin rash, musculoskeletal complaints, fatigue, hemorrhage, edema, hand-foot skin reaction, skin and hair discoloration, mucositis, hypertension, cardiac toxicity, hypothyroidism, liver transaminase changes, and hematological toxicity of imatinib and sunitinib. Potential drug-drug interactions with each respective agent are also discussed. With prudent use of supportive care measures, many side effects can be managed without dose reduction or interruption of treatment. On the other hand, individualized tailoring of the dose is often required to manage severe toxicity, such as painful hand-foot skin reactions, fatigue, hepatotoxicity, or cardiac toxicity. Management of many TKI-related adverse effects require further evaluation in prospective clinical trials.

[Angiogenesis inhibition: review of the activity of sorafenib, sunitinib and bevacizumab]

Renal cell carcinoma accounts for approximately 3% of all human malignancies. The use of cytokines in metastatic stage of disease has been the standard until last decades, presenting partial and short duration responses. Research on angiogenesis in renal carcinoma has brought important advances to understand tumor biology and to allow us development of new antiangiogenic drugs. Sunitinib (SUTENT), sorafenib (NEXAVAR) and bevacizumab (AVASTIN) are actually three molecules accepted to use in metastatic renal cell carcinoma (mRCC), with a good tolerability demonstrated in different studies. Clinical evidence shows sunitinib to be reference standard of care for the first-line treatment of mRCC. The use of bevacizumab in combination with interferon alfa (IFN alfa) can also be considered in this setting. Sorafenib is recommended for second-line treatment in cytokine-refractory patients, sunitinib being also accepted in this situation. Other combination of these molecules and their use as neo-adjuvant and adjuvant therapy is being evaluated and should change in the short term the management of the disease.

Targeted therapies in the treatment of GIST: Adverse events and maximising the benefits of sunitinib through proactive therapy management

BACKGROUND AND OBJECTIVES

The introduction of targeted therapies has led to improved clinical outcomes in patients with unresectable gastrointestinal stromal tumours (GIST). The receptor tyrosine kinase (RTK) inhibitor imatinib mesylate has been approved as the first-line choice of therapy for this group of patients, while the RTK inhibitor, sunitinib malate, has been approved for the treatment of GIST after disease progression or intolerance to imatinib. Here we discuss and compare the tolerability profiles of imatinib and sunitinib based on published clinical trial data. We also review available data on the potential mechanisms by which these agents may cause adverse events (AEs) and we propose some general strategies to help clinicians to optimise treatment benefit with these agents.

FINDINGS

While the toxicity profiles of imatinib and sunitinib are well known, the mechanisms of toxicity of these agents have yet to be elucidated fully. Clinical observations along with retrospective and prospective analyses suggest that some RTK inhibitor-related AEs have a higher incidence than previously reported from clinical trials. In addition, with greater use, new and unexpected AEs are emerging. Clinicians need to be familiar with the toxicity profiles of RTK inhibitors as well as individual patient risk factors in order to optimise treatment benefit.

CONCLUSIONS

Imatinib and sunitinib are generally well tolerated with known and manageable AE profiles. Proactive therapy management strategies can enable treatment optimisation and allow patients to continue treatment with minimal interruption.

EGFR tyrosine kinase inhibitor (PD153035) improves glucose tolerance and insulin action in high-fat diet-fed mice

OBJECTIVE

In obesity, an increased macrophage infiltration in adipose tissue occurs, contributing to low-grade inflammation and insulin resistance. Epidermal growth factor receptor (EGFR) mediates both chemotaxis and proliferation in monocytes and macrophages. However, the role of EGFR inhibitors in this subclinical inflammation has not yet been investigated. We investigated, herein, in vivo efficacy and associated molecular mechanisms by which PD153035, an EGFR tyrosine kinase inhibitor, improved diabetes control and insulin action.

RESEARCH DESIGN AND METHODS

The effect of PD153035 was investigated on insulin sensitivity, insulin signaling, and c-Jun NH(2)-terminal kinase (JNK) and nuclear factor (NF)-kappaB activity in tissues of high-fat diet (HFD)-fed mice and also on infiltration and the activation state of adipose tissue macrophages (ATMs) in these mice.

RESULTS

PD153035 treatment for 1 day decreased the protein expression of inducible nitric oxide synthase, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 in the stroma vascular fraction, suggesting that this drug reduces the M1 proinflammatory state in ATMs, as an initial effect, in turn reducing the circulating levels of TNF-alpha and IL-6, and initiating an improvement in insulin signaling and sensitivity. After 14 days of drug administration, there was a marked improvement in glucose tolerance; a reduction in insulin resistance; a reduction in macrophage infiltration in adipose tissue and in TNF-alpha, IL-6, and free fatty acids; accompanied by an improvement in insulin signaling in liver, muscle, and adipose tissue; and also a decrease in insulin receptor substrate-1 Ser(307) phosphorylation in JNK and inhibitor of NF-kappaB kinase (IKKbeta) activation in these tissues.

CONCLUSIONS

Treatment with PD153035 improves glucose tolerance, insulin sensitivity, and signaling and reduces subclinical inflammation in HFD-fed mice.

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.

Blood glucose levels in patients with metastatic renal cell carcinoma treated with sunitinib

Sunitinib, a multitargeted tyrosine-kinase inhibitor, extends survival of patients with metastatic renal cell carcinoma (mRCC) and gastrointestinal stromal tumours. Between October 2005 and March 2007, we retrospectively reviewed blood glucose level variations associated with sunitinib therapy in patients treated for mRCC. Nineteen of the patients had type II diabetes. All 19 patients had a decrease in blood glucose level (mean 1.77 mmol l(-1)) after 4 weeks of treatment. This was followed by re-elevation in the 2-week rest period. After two cycles of sunitinib administration, two patients had stopped blood glucose-lowering drugs whereas five other patients had normalised their blood glucose level. On the basis of pre-clinical data, we hypothesise that several mechanisms could be involved in this process, such as capillary regression of pancreatic islets, IGF-1 modulation through HIF1-alpha or NF-kappaB activation. In addition, a decrease of glucose uptake in the context of concomitant gastrointestinal toxicity cannot be excluded. Glycaemic control should be carefully evaluated in diabetic patients treated with sunitinib, and routine monitoring is warranted.