Dual PI3Kδγ inhibition demonstrates potent anticancer effects in diffuse large B-cell lymphoma models: Discovery and preclinical characterization of LL-00084282.

Phosphoinositide 3-kinase (PI3K) pathway mediates key signaling events downstream to B-cell receptor (BCR) for survival of mature B-cells, and overexpression or overactivation of PI3Kδ is crucial for B-cell malignancies such as diffuse large B-cell lymphoma (DLBCL). Small molecule PI3Kδγ inhibitors, with a known potential to reduce activated B-cell (ABC)-DLBCL transformation, form an important class of therapeutics approved for follicular lymphoma (FL), chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL). In this study, we describe discovery of a potent, selective and efficacious dual PI3Kδγ inhibitor, LL-00084282, having a differentiated efficacy profile in human ABC- and germinal center B-cell (GCB)-DLBCL cell lines. LL-00084282 displayed high potency and superior PI3Kδγ engagement with excellent selectivity over other PI3K isoforms at both IC50/90 concentrations in biochemical and cell-based assays. In contrast to selective PI3Kδ inhibitors, LL-00084282 showed superior and potent anticancer activity in both ABC- and GCB-DLBCL cell lines. LL-00084282 demonstrated in-vivo efficacy in OCI-Ly10 and SU-DHL-6 xenografts with good tolerability. Furthermore, LL-00084282 inhibited pro-inflammatory cytokine secretion and reduced basophil activation in human PBMCs, showing potential implications in immunoinflammatory conditions. Good pharmacokinetic properties in higher species and desirable efficacy profile highlights potential of this novel PI3Kδγ inhibitor for further clinical evaluation in DLBCL patients.

Discovery of a Potent and Selective PI3Kδ Inhibitor (S)-2,4-Diamino-6-((1-(7-fluoro-1-(4-fluorophenyl)-4-oxo-3-phenyl-4H-quinolizin-2-yl)ethyl)amino)pyrimidine-5-carbonitrile with Improved Pharmacokinetic Profile and Superior Efficacy in Hematological Cancer Models.

PI3Kδ inhibitors have been approved for B-cell malignancies like CLL, small lymphocytic lymphoma, and so forth. However, currently available PI3Kδ inhibitors are nonoptimal, showing weakness against at least one of the several important properties: potency, isoform selectivity, and/or pharmacokinetic profile. To come up with a PI3Kδ inhibitor that overcomes all these deficiencies, a pharmacophoric expansion strategy was employed. Herein, we describe a systematic transformation of a "three-blade propeller" shaped lead, 2,3-disubstituted quinolizinone 11, through a 1,2-disubstituted quinolizinone 20 to a novel "four-blade propeller" shaped 1,2,3-trisubstituted quinolizinone 34. Compound 34 has excellent potency, isoform selectivity, metabolic stability across species, and exhibited a favorable pharmacokinetic profile. Compound 34 also demonstrated a differentiated efficacy profile in human germinal center B and activated B cell-DLBCL cell lines and xenograft models. Compound 34 qualifies for further evaluation as a candidate for monotherapy or in combination with other targeted agents in DLBCLs and other forms of iNHL.

An experimental assessment of toxic potential of nanoparticle preparation of heavy metals in streptozotocin induced diabetes.

Nanoparticle preparations of heavy metals have attracted enormous scientific and technological interest. Biologically produced nanoparticle preparations of heavy metals are elaborately described in traditional texts and being widely prescribed. The underlying interactions of nano preparations within the physiological fluids are key feature to understand their biological impact. In this perspective, we performed an experimental assessment of the toxicity potential of a marketed metallic preparation named Vasant Kusumakar Ras (VKR), wherein different heavy metals in composite form are reduced to nanoparticle size to produce the desired effect in diabetes and its complications. VKR (50mg/kg) was administered to Albino Wistar rats rendered diabetic using streptozotocin (90mg/kg) in 2 days old neonates. Anti-hyperglycemic effect was observed with VKR along with increased levels of plasma insulin. Renal variables including total proteins and albumin along with glomerular filtration rate were found to improve biochemically. The results were supplemented by effects on different inflammatory and growth factors like TNF-α, nitric oxide, TGF-ß and VEGF. However, the results observed in kidney histopathology were not in accordance with the biochemical parameters. Inflammation observed in kidney was confirmed by immunostaining metallothionein, which was due to the accumulation of heavy metals. Furthermore, mercury accumulation in kidney further confirmed by autometallography, which activated mononuclear phagocyte system, which generated an immune response. This was further supported by increase in the extent of apoptosis in kidney tissues. In conclusion, nanoparticle preparations of heavy metals can be toxic to kidney if it is not regulated with respect to its surface chemistry and dosage.

Potential nephrotoxic effects produced by steroidal saponins from hydro alcoholic extract of Tribulus terrestris in STZ-induced diabetic rats.

Chronic hyperglycemia leads to the development of microvascular complications like diabetic nephropathy. The present study investigated the potential effects of the hydroalcoholic extract of Tribulus terrestris, a plant of Zygophyllaceae family, on the renal complications in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by administering STZ (90 mg/kg) to the 2-days old neonates. After 6 weeks of induction, diabetic rats were treated with 50 mg/kg hydroalcoholic extract of T. terrestris for 8 weeks. The anti-hyperglycaemic nature was confirmed by reduction in blood glucose and improvement in insulin levels. Diabetic renal injury associated with decrease in total proteins and albumin levels was observed to be improved by T. terrestris extract. Glomerular filtration rate along with inflammatory and growth factors, adiponectin and erythropoietin were also improved by the treatment, though the findings were not significant. However, the beneficial antidiabetic effects of T. terrestris extract in plasma were not observed in kidney histopathology. This was confirmed by the quantitative estimation of unhydrolyzed fraction of saponins (major component: protodioscin) in plasma and kidney samples of normal and diabetic rats. Hence, it can be concluded that 8 weeks treatment with T. terrestris extract produces potential toxic effects in kidney, which are independent of its anti-diabetic action.

Aliskiren improves insulin resistance and ameliorates diabetic renal vascular complications in STZ-induced diabetic rats.

Aliskiren, a direct renin inhibitor (DRI), has therapeutic effects in patients with hypertension and associated complications, but its potential mechanism in diabetic nephropathy is lacking. The effects of aliskiren in Streptozotocin (STZ)-induced renal complication in diabetic rats were investigated. Aliskiren treatment for eight weeks at the dose of 10 mg/kg/day, via osmotic mini-pump, induced improvement in blood glucose levels, systolic blood pressure (BP) and serum creatinine. Improvement of insulin resistance by aliskiren was confirmed by increased glucose translocation in liver and muscle and hence insulin levels. The treated group also showed improvement in glomerulosclerosis and tubulointerstitial injury. Aliskiren treatment also improved albumin levels in plasma, suppressed profibrotic and proinflammatory cytokine synthesis viz TNF-α and TGF-ß and angiogenesis by a decrease in VEGF. In addition, the level of total proteins and GFR via cystatin c and beta-2microglobulin along with adiponectin and erythropoietin were also improved. These results suggest that the beneficial organ protective effect of aliskiren is mediated by improvement in insulin resistance as well as a direct anti-fibrotic effect in the target organ in STZ-induced diabetic rats with a slight effect on blood pressure. Aliskiren may be a useful therapeutic agent in the treatment of type 2 diabetes and diabetic nephropathy.

Anti-inflammatory action of Tamarind seeds reduces hyperglycemic excursion by repressing pancreatic ß-cell damage and normalizing SREBP-1c concentration.

CONTEXT: Tamarindus indica L. (Leguminosae) is widely used as a traditional medicine for the management of diabetes mellitus (DM) in India, in addition to its anti-inflammatory activity. The present study has been designed to understand the correlation involved between antidiabetic and anti-inflammatory action of aqueous seed extract of T. indica (TSE) in diabetic rats. OBJECTIVE: In view of the fact that fatty acid synthesis and insulin release from islets of pancreas are regulated by sterol regulatory element-binding proteins (SREBP-1c) and cytosolic calcium, respectively, the objectives of present study were to determine the influence of TSE on SREBP-1c mRNA and to investigate the intracellular islets calcium [Ca²âº](I) involvement and ß-cell mass preservation in insulin secretagogue action of TSE. MATERIALS AND METHODS: The effect of 4 weeks oral treatment (120 and 240 mg/kg) of high-performance liquid chromatography (HPLC) standardized TSE was studied in streptozotocin (STZ)-induced diabetic male Wistar rats. Reverse transcription-PCR (RT-PCR) and a spectrofluorometer were used for mRNA concentration and islets [Ca²âº](I) determination, respectively. The TUNEL assay was followed to study the pancreatic apoptosis. RESULTS: TSE (120 and 240 mg/kg) showed positive correlation with [Ca²âº](I) and insulin release. The anti-inflammatory action of TSE was significant on nitric oxide (NO) and tumor necrosis factor-α (TNF-α) in addition to a favorable effect on ß-cell neogenesis and improved mRNA concentration of SREBP-1c. DISCUSSION AND CONCLUSION: The results suggest that anti-inflammatory action of Tamarind seeds on ß-cell cells of islets and cytokines contribute toward its antidiabetic activity by way of complex mechanisms of [Ca²âº](I) handling and through SREBP-1c gene in liver.

Chronic DPP-IV inhibition with PKF-275-055 attenuates inflammation and improves gene expressions responsible for insulin secretion in streptozotocin induced diabetic rats.

Inhibitors of dipeptidyl peptidase-4 (DPP-IV), a key regulator of the actions of incretin hormones, exert antihyperglycemic effects in type 2 diabetic patients. A major question concerns the potential ability of long term DPP-IV inhibition to have beneficial disease-modifying effects, specifically to attenuate loss of pancreatic ß-cell mass due to oxidative stress induced inflammation. Here, we investigated the effects of a potent and selective DPP-4 inhibitor, an analog of vildagliptin (PKF-275-055), on glycemic control, pancreatic ß-cell mass, genes and proteins expressions, tumor necrosis factor-alpha, and nitric oxide in an n2-STZ diabetic model of rat with defects in insulin sensitivity and secretion. To induce NIDDM, streptozotocin (STZ) 90 mg/kg was administered i.p. to a group of 2 days old pups. Diabetic rats were administered orally with vildagliptin analog PKF-275-055. Saline treated animals served as diabetic control. Significant and dose-dependent correction of postprandial hyperglycemia was observed in diabetic rats following 8 weeks of chronic therapy. Treatment with PKF-275-055 showed increased the number of insulin-positive ß-cells in islets and improved the expressions of genes and proteins are responsible for insulin secretions. In addition, treatment of rats with PKF-275-055 significantly increased insulin content, glycogen content and total proteins content; and decreased the inflammatory markers i.e. nitric oxide and TNF-alpha. The present studies indicate that PKF-275-055 is a novel selective DPP-IV inhibitor having potential to reduce inflammation that might be a potential agent for type 2 diabetes.

Vildagliptin selectively ameliorates GLP-1, GLUT4, SREBP-1c mRNA levels and stimulates ß-cell proliferation resulting in improved glucose homeostasis in rats with streptozotocin-induced diabetes.

OBJECTIVE: Inhibitors of dipeptidyl peptidase-4 (DPP-4), a key regulator of the actions of incretin hormones, exert antihyperglycemic effects in type 2 diabetic patients. A major unanswered question concerns the potential ability of DPP-4 inhibition to have beneficial disease-modifying effects, specifically to attenuate loss of pancreatic ß-cell mass and function due to oxidative stress induced inflammation. Here, we investigated the effects of a potent and selective DPP-4 inhibitor vildagliptin on glycemic control, pancreatic ß-cell mass and function, genes and proteins expressions, tumor necrosis factor-alpha, and nitric oxide in an n2-STZ diabetic model of rat with defects in insulin sensitivity and secretion. METHOD: To induce NIDDM, STZ (sigma chemicals, USA) (90 mg/kg) was administered i.p. to a group of 2 days old pups. Another group of pups received only saline. The pups were weaned for 21 days, and 6 weeks after the injection of STZ, the animals were checked for fasting glucose level (FPG) ≥160 mg/dl were considered as diabetic. RESULTS: Significant and dose-dependent correction of postprandial and fasting hyperglycemia was observed in diabetic rats following 8 weeks of chronic therapy. Treatment with vildagliptin showed increase in the number of insulin-positive ß-cells in islets and improved the expressions of genes and proteins are responsible for insulin secretions. In addition, treatment of rats with vildagliptin significantly increased insulin content; and decreased the nitric oxide and TNF-alpha concentration. CONCLUSION: These findings suggest that DPP-4 inhibitors may offer long-lasting efficacy in the treatment of diabetes mellitus by modifying the courses of the disease.

Effective blockade of RAAS by combination of aliskiren and olmesartan improves glucose homeostasis, glomerular filtration rate along with renal variables in streptozotocin induced diabetic rats.

The present study aims to investigate the combined and individual treatment of aliskiren and olmesartan for 8 weeks in streptozotocin induced diabetic rats provide an effective blockade of RAAS by improving glucose homeostasis, glomerular filtration rate along with renal variables thereby delaying the progression of the disease. Streptozotocin induced diabetic rats were administered with aliskiren (10mg/kg/day), olmesartan (6mg/kg/day) alone and in combination. To identify the glucose homeostasis, translocation of glucose transporter proteins in liver and muscle was observed by their expression after treatment. Glomerular filtration rate is estimated using serum creatinine, cystatin C and beta 2 microglobulin. This study also examined the effects of combination and monotherapy on various renal variables viz. albumin, total proteins, TGF-ß, TNF-α, VEGF, nitric oxide, adiponectin and erythropoeitin. In addition, histopathological and anti-apoptotic profile of kidney was also investigated. The present study indicates that dual blockade of RAAS improved glucose homeostasis and confirms the nephroprotective effects of the combined treatment of aliskiren and olmesartan independent of their antihypertensive property in the STZ induced diabetes. In addition, its antifibrotic, antiproteinuric effects indicate that combination treatment might be potential as an important therapeutic option for chronic fibrotic diseases in renal complications.

A novel long acting DPP-IV inhibitor PKF-275-055 stimulates ß-cell proliferation resulting in improved glucose homeostasis in diabetic rats.

The enzyme dipeptidyl peptidase-IV (DPP-4) inactivates the incretin hormone glucagon-like peptide-1 (GLP-1). GLP-1 has therapeutic effects in patients with type 2 diabetes, but its potential is limited by a short half-life, DPP-4 inhibition is a promising approach to diabetes treatment. This study examined chronic (once-a-day dosing for 8 weeks) effects of the DPP-4 inhibitor PKF-275-055 (1, 3, and 10mg/kg) on ß-cell regeneration and plasma DPP-IV activity, intact GLP-1, glucose, and insulin after an oral glucose load in neonatal wistar rats injected with streptozotocin (STZ) (n2-STZ model), a recognized model of type 2 diabetes. In streptozotocin induced diabetic rats, PKF-275-055 (3, and 10mg/kg) significantly reduced glucose excursion during the oral glucose tolerance test conducted 2h and 10h after administration, with increases in plasma insulin and active glucagon-like peptide-1 (GLP-1) levels and significantly inhibited (> 50% inhibition) plasma DPP-IV activity during both the 1st and 2nd OGTT in diabetic rats. In contrast, PKF-275-055 (1-10mg/kg) did not cause hypoglycemia in fasted normal rats. Furthermore, PKF-275-055 significantly inhibited advance glycation end product (HbA1c), HOMA-Index, gastric emptying and small intestinal transit rates, with significance at doses of 1mg/kg or higher. Immunological staining showed PKF-275-055 stimulates ß-cell regeneration and reduces pancreatic cell apoptosis in diabetic treated rats. The present preclinical studies indicate that PKF-275-055 is a novel selective DPP-IV inhibitor with long-acting antidiabetic effect that might be a potential agent for type 2 diabetes.

Relationships between the islets blood flow, nitric oxide, insulin, and cytosolic calcium in rat pancreatic islets: effects of DPP-IV inhibitor vildagliptin.

The aim of the present study was to evaluate the relationships between the islets blood flow, nitric oxide, insulin, and cytosolic calcium in rat pancreatic islets, using dipeptidyl peptidase-IV (DPP-IV) inhibitor vildagliptin. For measuring pancreatic and islets blood a non-radioactive microsphere technique was used. Vehicle pre-treatment of glucose administered diabetic rats had decrease pancreatic and islets blood flow as compared with glucose administered normal rats. Blood glucose concentrations were not affected after vildagliptin administration in either diabetic or normal rats (10 min after glucose administration). Vildagliptin had no effects on baseline pancreatic or islets blood flow in glucose administered normal rats. Administration of vildagliptin increased both pancreatic and islets blood flow as compared with vehicle treated diabetic rats. Furthermore, diabetic rats showed significant increase in NO and decrease in insulin secretions and vice versa in normal rats. Vildagliptin pre-treatment to both normal and diabetic rats had shown mild decrease in NO, but significantly increased insulin secretions. In addition, vildagliptin itself is able to mobilize intracellular Ca(2+) in pancreatic islets both in absence and presence of glucose. From the present study, we conclude following points (A) administration of vildagliptin augmented the blood flow seen in islets of diabetic rats, (B) islets insulin secretions are independent of islets blood flow and NO, (C) vildagliptin inhibited excessive NO production in diabetic rats that prevents the damage to ß-cells due to excessive production of peroxynitrite (ONOO(-)) ions and protects from cytokine-induced suppression of insulin release.