Antitumor alkyl-lysophospholipid analog edelfosine induces apoptosis in pancreatic cancer by targeting endoplasmic reticulum

Pancreatic cancer remains as one of the most deadly cancers, and responds poorly to current therapies. The prognosis is extremely poor, with a 5-year survival of less than 5%. Therefore, search for new effective therapeutic drugs is of pivotal need and urgency to improve treatment of this incurable malignancy. Synthetic alkyl-lysophospholipid analogs (ALPs) constitute a heterogeneous group of unnatural lipids that promote apoptosis in a wide variety of tumor cells. In this study, we found that the anticancer drug edelfosine was the most potent ALP in killing human pancreatic cancer cells, targeting endoplasmic reticulum (ER). Edelfosine was taken up in significant amounts by pancreatic cancer cells and induced caspase-and mitochondrial-mediated apoptosis. Pancreatic cancer cells show a prominent ER and edelfosine accumulated in this subcellular structure, inducing a potent ER stress response, with caspase-4, BAP31 and c-Jun NH 2-terminal kinase (JNK) activation, CHOP/GADD153 upregulation and phosphorylation of eukaryotic translation initiation factor 2 a-subunit that eventually led to cell death. Oral administration of edelfosine in xenograft mouse models of pancreatic cancer induced a significant regression in tumor growth and an increase in apoptotic index, as assessed by TUNEL assay and caspase-3 activation in the tumor sections. The ER stress-associated marker CHOP/GADD153 was visualized in the pancreatic tumor isolated from edelfosine-treated mice, indicating a strong in vivo ER stress response. These results suggest that edelfosine exerts its pro-apoptotic action in pancreatic cancer cells, both in vitro and in vivo, through its accumulation in the ER, which leads to ER stress and apoptosis. Thus, we propose that the ER could be a key target in pancreatic cancer, and edelfosine may constitute a prototype for the development of a new class of antitumor drugs targeting the ER. �� 2012 Macmillan Publishers Limited All rights reserved.

Nerve pathology in the type 1 diabetic dog: effects of treatment with sulindac

The purpose of this study was to define pathological abnormalities in the peripheral nerve of a large animal model of long-duration type 1 diabetes and also to determine the effects of treatment with sulindac. Detailed morphometric studies were performed to define nerve fiber and endoneurial capillary pathology in 6 control dogs, 6 type 1 diabetic dogs treated with insulin, and 6 type 1 diabetic dogs treated with insulin and sulindac for 4 years. Myelinated fiber and regenerative cluster density showed a non-significant trend toward a reduction in diabetic compared to control animals, which was prevented by treatment with sulindac. Unmyelinated fiber density did not differ among groups. However, diabetic animals showed a non-significant trend toward an increase in axon diameter (p <0.07), with a shift of the size frequency distribution towards larger axons, which was not prevented by treatment with sulindac. Endoneurial capillary density and luminal area showed a non-significant trend toward an increase in diabetic animals, which was prevented with sulindac treatment. Endoneurial capillary basement membrane area was significantly increased (p <0.05) in diabetic animals, but was not prevented with sulindac treatment. We conclude that the type 1 diabetic dog demonstrates minor structural abnormalities in the nerve fibers and endoneurial capillaries of the sciatic nerve, and treatment with sulindac ameliorates some but not all of these abnormalities.

Polyamine system in developing rat eye and an animal model of retinopathy of prematurity

BACKGROUND: In experimental models of retinopathy of prematurity (ROP), a vasoproliferative disorder of the retina, retinal lesions are usually assessed by morphological examination. However, studies suggest that the polyamine system may be useful in monitoring proliferation processes. For this reason, polyamine concentrations in rat erythrocytes (RBC) and the regulation of polyamine system in rat eyes under the conditions relevant to ROP were investigated. METHODS: Newborn Wistar rats were reared in room air (control) or exposed first to hyperoxia (60% or 80% oxygen, 2 weeks) and then to normoxia (relative hypoxia, 1 or 2 weeks). Blood was collected from orbital vessels at 2 weeks of age and before death. Polyamine system-related enzyme activities were measured in retina and lens with radioassays. Polyamines were quantified by fluorometry after extraction, dansylation and HPLC separation. RESULTS: Oxygen (80% only) significantly decreased RBC polyamine concentrations, which then markedly increased after rats were transferred for a week to normal air, suggesting retardation of growth processes and compensatory stimulation, respectively. However, polyamine system changes in the rat eye were not so pronounced. Enzyme activities and polyamine concentrations tended to be lower in retina after hyperoxia and were only slightly higher, with the exception of ornithine decarboxylase, after a subsequent 1 week of normoxia. In litters subjected to normoxia for longer periods no changes were found. CONCLUSION: The transient and short-lived alteration in polyamine metabolism, especially in the eye, suggests that exposure of newborn rats to high oxygen supplementation followed by normoxia does not necessarily result in marked retinopathy.

Selective loss of vascular smooth muscle cells in the retinal microcirculation of diabetic dogs

This study was undertaken to further characterise the fine structural changes occurring in the retinal circulation in early diabetes. The eyes of eight alloxan/streptozotocin and three spontaneously diabetic dogs were examined by trypsin digest and electron microscopy after durations of diabetes of between 1 and 7 years. Basement membrane (BM) thickening in the retinal capillaries was the only obvious fine structural change identified during the first 3 years of diabetes and was established within 1 year of induction. Widespread pericyte loss was noted after 4 years of diabetes and was paralleled by loss of smooth muscle (SM) cells, in the retinal arterioles. SM cell loss was most obvious in the smaller arterioles of the central retina. No microaneurysms were noted in the experimental diabetic dogs with up to 5 years' duration of diabetes but were widespread in a spontaneously diabetic animal at 7 years. This study has shown that SM cell loss, a hitherto unrecognised feature of diabetic microangiopathy, accompanies pericyte loss in the retinal circulation of diabetic dogs.

Ultrastructural findings in solar retinopathy

This study documents the ultrastructural findings in a case of solar retinopathy, 6 days after sungazing. A malignant melanoma of the choroid was diagnosed in a 65-year-old man. On fundoscopy, the macula was normal. The patient agreed to stare at the sun prior to enucleation. A typical solar retinopathy developed, characterised by a small, reddish, sharply circumscribed depression in the foveal area. Structural examination of the fovea and parafovea revealed a spectrum of cone and rod outer segment changes including vesiculation and fragmentation of the photoreceptor lamellae and the presence of discrete 100-120 nm whorls within the disc membranes. Many photoreceptor cells, particularly the parafoveal rods, also demonstrated mitochondrial swelling and nuclear pyknosis. Scattered retinal pigment epithelial cells in the fovea and parafovea showed a degeneration characterised by loss of plasma membrane specialisations, swelling of the smooth endoplasmic reticulum and changes in the fine structure of the lipofuscin granules. The good visual prognosis in solar retinopathy was attributed to the resistance of the foveal cone cells to photochemical damage.

A morphologic and autoradiographic study of cell death and regeneration in the retinal microvasculature of normal and diabetic rats

Cell loss and regeneration were investigated and compared in the retinal microvasculature of age- and sex-matched normal and streptozotocin diabetic rats. Selective pericyte loss in the diabetic rat was characterized by changes in the pericyte to endothelial cell ratio in retinal capillaries isolated for microscopy by the trypsin digest technique. A comparison of 3- and 9-month-old normal rats showed no significant change in the pericyte to endothelial cell ratio (1:2.7). In diabetic animals the ratio was reduced to 1:4.03, which was statistically significant (P less than .001). Premitotic retinal vascular cells in normal and diabetic rats were labelled with tritiated thymidine and the labelling indices calculated from cell counts of trypsin digest preparations. Methyl H3 thymidine was infused continuously over an eight-day period using osmotic mini pumps. The labelling index of endothelial cells (0.33%) in normal rats increased to 0.91% in diabetic animals (P less than .05). The labelling index of pericyte cells in normal animals (0.16%) did not increase significantly (P greater than .05) in diabetic animals (0.19%). A special stain was used to exclude labelled polymorphonuclear leukocytes from the cell counts.

Genetic and Epigenetic Risk Factors for Diabetic Kidney Disease

Diabetes is increasing at daunting rates worldwide, and approximately 40% of affected individuals will develop kidney complications. Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and there are significant healthcare costs providing appropriate renal replacement therapies to affected individuals. For several decades, investigators have sought to discover inherited risk factors and biomarkers for DKD. In recent years, advances in high-throughput laboratory techniques and computational analyses, coupled with the establishment of multicenter consortia, have helped to identify genetic loci that are replicated across multiple populations. Several genome-wide association studies (GWAS) have been conducted for DKD with further meta-analysis of GWAS and comprehensive ���single gene��� meta-analyses now published. Despite these efforts, much of the inherited predisposition to DKD remains unexplained. Meta-analyses and integrated���omics pathway studies are being used to help elucidate underlying genetic risks. Epigenetic phenomena are increasingly recognized as important drivers of disease risk, and several epigenome-wide association studies have now been completed. This review describes key findings and ongoing genetic and epigenetic initiatives for DKD.

Epigenetics of diabetic nephropathy

Diabetes is responsible for a large proportion of chronic kidney disease and end-stage renal disease worldwide. Careful monitoring and balanced control of blood glucose for individuals with type 1 diabetes can delay or prevent the onset of micro- and macro-vascular complications, however hyperglycaemia does not explain all of the risk for these diabetic complications. Genetic risk factors for diabetic nephropathy are being identified through international collaborations. However despite these advances a significant proportion of susceptibility remains unexplained, the so-called ���missing heritability���.