Amelioration of diabetes by imatinib mesylate (Gleevec): role of beta-cell NF-kappaB activation and anti-apoptotic preconditioning

Tyrosine kinase inhibitors reverse type 1 diabetes in nonobese diabetic mice

The recent development of small-molecule tyrosine kinase (TK) inhibitors offers increasing opportunities for the treatment of autoimmune diseases. In this study, we investigated the potential of this new class of drugs to treat and cure type 1 diabetes (T1D) in the NOD mouse. Treatment of prediabetic and new onset diabetic mice with imatinib (Gleevec) prevented and reversed T1D. Similar results were observed with sunitinib (Sutent), an additional approved multikinase inhibitor, suggesting that the primary target of imatinib, c-Abl, was not essential in blocking disease in this model. Additional studies with another TK inhibitor, PLX647 (targeting c-Kit and c-Fms) or an anti-c-Kit mAb showed only marginal efficacy whereas a soluble form of platelet-derived growth factor receptor (PDGFR), PDGFRbetaIg, rapidly reversed diabetes. These findings strongly suggest that inhibition of PDGFR is critical to reverse diabetes and highlight a crucial role of inflammation in the development of T1D. These conclusions were supported by the finding that the adaptive immune system was not significantly affected by imatinib treatment. Finally, and most significantly, imatinib treatment led to durable remission after discontinuation of therapy at 10 weeks in a majority of mice. Thus, long-term efficacy and tolerance is likely to depend on inhibiting a combination of tyrosine kinases supporting the use of selective kinase inhibitors as a new, potentially very attractive approach for the treatment of T1D.

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.

Imatinib mesylate improves insulin sensitivity and glucose disposal rates in rats fed a high-fat diet

The aim of the present study was to investigate whether imatinib affects insulin sensitivity and glucose disposal in HF (high-fat)-fed rats. Sprague-Dawley rats were fed either a standard pelleted rat food (low-fat diet) or an HF diet (60% fat) for 8 weeks. During the last 10 days of the HF diet regime, rats received saline alone or imatinib (50 or 100 mg/kg of body weight) daily by gavage. The higher dose of imatinib resulted in a decreased psoas fat pad weight in the HF-treated rats. Under euglycaemic hyperinsulinaemic clamp conditions, HF-fed rats exhibited increased insulin concentrations and decreased glucose disposal. The lower (50 mg/kg of body weight), but not the higher (100 mg/kg of body weight), dose of imatinib normalized insulin sensitivity and glucose disposal without affecting glucose metabolism in low-fat-fed rats. Hepatic glucose production at both fasting and hyperinsulinaemic conditions was only weakly affected by imatinib. We conclude that a moderate dose of imatinib efficiently counteracts HF-induced peripheral insulin resistance, and that further studies on the mechanisms by which imatinib increases insulin action in muscle and fat tissues might generate novel strategies for the treatment of Type 2 diabetes.