Cancer-associated retinopathy as the leading symptom in colon cancer.
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ABSTRACT:
SUBMITTER: Weixler B
PROVIDER: S-EPMC4736525 | biostudies-other | 2016 Feb
REPOSITORIES: biostudies-other
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Project description:Upregulation of Smad7, an inhibitor of transforming growth factor-β1 (TGF-β1), occurs in sporadic colorectal cancer (CRC) and knockdown of Smad7 inhibits CRC cell growth, a phenomenon that associates with decreased expression of cell division cycle 25 homolog A and arrest of cells in the S phase of the cell cycle. These findings occur in CRC cells unresponsive to TGF-β1, thus suggesting the existence of a Smad7-mediated TGF-β1-independent mechanism that controls CRC cell behavior. Here we show that Smad7 inhibition with a specific Smad7 antisense oligonucleotide upregulates eukaryotic translation initiation factor 2α (eIF2α) phosphorylation, a transcription factor involved in the regulation of cell cycle arrest and induction of cell death, and induces activating transcription factor 4 (ATF4) and CCAAT/enhancer binding protein homology protein (CHOP), two downstream targets of eIF2α. Among the upstream kinases that control eIF2α phosphorylation, the serine-threonine protein kinase RNA (PKR), but not general control non-derepressible 2 (GCN2) and protein kinase RNA-like endoplasmic reticulum kinase (PERK), is activated by Smad7 knockdown. PKR silencing abolishes Smad7 antisense-induced eIF2α phosphorylation and ATF4/CHOP induction, thereby preventing Smad7 antisense-driven cell death. Smad7 inhibition diminishes interaction of PKR with protein kinase inhibitor p58 (p58IPK), a cellular inhibitor of PKR, but does not change the expression and/or activity of other factors involved in the control of PKR activation. These findings delineate a novel mechanism by which Smad7 knockdown promotes CRC cell death.
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Project description:BACKGROUND:The early diagnosis of cancer is of crucial importance and a key prognostic factor. Cancer-associated retinopathy (CAR) can be symptomatic prior to other manifestations directly related to malignant tumors. The aim of this study was to show that, in selected cases, ophthalmic findings are consistent enough with the diagnosis of CAR to trigger investigations aimed at detecting a previously unknown malignancy. METHODS:This was a monocentric retrospective case series performed in a tertiary referral center. Patients with a diagnosis of CAR were included. Diagnosis was based on the clinical presentation, the visual field and electroretinogram alterations. The clinical presentation, visual field testing and electroretinographic results were analyzed as well as the malignancies identified following the diagnosis of CAR. Follow-up data was collected. RESULTS:Four patients (two men, two women, median age 65.5 years) were included. All patients presented with posterior segment inflammation at initial presentation as well as advanced visual field loss and an extinguished electroretinogram. The best corrected decimal visual acuity was 0.8 or better in both eyes of three patients and decreased to 0.3 OD and O.2 OS in one patient due to a bilateral macular edema. No patient had a previously known history of cancer. Once the diagnosis of CAR was made, investigations aimed at identifying a malignant tumors subsequently led to the diagnosis of two cases of small cell lung tumors, of one prostate carcinoma and of a uterine sarcoma. The treatment of CAR included plasmapheresis, systemic corticosteroids, azathioprine, cyclosporine and periocular or intraocular corticosteroid injections. In all cases the intraocular inflammation resolved, but pigment mottling, diffuse retinal atrophy, optic disc pallor and arterial narrowing were among manifestations observed during the follow-up of the patients. CONCLUSION:In selected patients, findings suggestive of CAR can be useful for the early detection of a cancer.
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Project description:INTRODUCTION: Cancer-associated retinopathy (CAR) is a paraneoplastic neurological syndrome resulting in progressive loss of vision and clinical signs of retinal degeneration. It is associated with various types of cancer and is also considered to be an autoimmune disorder that involves cross-reaction between autoantibodies and retinal proteins. The aim of this study was to establish whether immunoreactivity to retinal antigens (RAs) observed in patients with breast cancer is accompanied by any visual impairments. MATERIALS AND METHODS: Sera of 295 patients with diagnosed breast cancer were screened for the presence of anti-RAs antibodies using immunoblotting. Cellular immunoreactivity to RAs present in retinal extracts and to purified recoverin and arrestin was determined by means of a lymphocyte proliferation assay. Six patients with high-titer antibodies to RAs then underwent ophthalmic and neurological examinations. RESULTS: Four serum samples contained high-titer antibodies to a 46-kDa protein, most probably retinal alpha-enolase, three had antibodies to a 48-kDa protein identified as retinal arrestin, while 56-, 43-, 41-, and 34-kDa antigens were recognized only by one serum sample each. Moreover, weak cellular response to all the RAs tested was observed in one patient and another patient responded only to retinal extract. Two of the examined patients displayed symptoms of CAR. CONCLUSIONS: Immunoreactivity to RAs in patients with breast cancer may also be present in cases without clinical signs of CAR.
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Project description:PurposeAutoantibodies (AAbs) with different retinal specificities were reported in cancer-associated retinopathy (CAR) and autoimmune retinopathy (AR). The goal was to identify the small retinal proteins of apparent molecular mass of 23-kDa often recognized by patients' AAbs.MethodsSera specific for a 23-kDa retinal protein of 173 patients were investigated retrospectively by Western blotting and double immunofluorescence confocal microscopy. A proteomic analysis revealed new 23-kDa protein candidates, including guanylyl cyclase-activating proteins (GCAPs), heat shock protein 27 (HSP27), and Rab6A GTPase (Rab6A).ResultsAmong the cohort of 173 patients, only 68 had anti-recoverin AAbs and the remaining 105 reacted with 4 unique proteins, which were identified as a Rab6A, HSP27, GCAP1, and GCAP2. Confocal images from a double labeling study confirmed the reactivity of AAbs with different types of cells in human retina, consistent with the target protein's respective cellular functions. Patients (62/173) had been diagnosed with various kinds of cancer, including 20% of patients who had anti-recoverin, 11% anti-Rab6A, and 5% anti-HSP27 AAbs. Only 50% of recoverin-seropositive patients had cancer and the individuals with anti-recoverin AAbs had a significantly higher likelihood to be diagnosed with cancer than patients with other anti-23-kDa AAbs.ConclusionsThe newly discovered retinal autoantigens may be involved in pathogenicity of CAR and AR. The recognition of AAbs against various retinal proteins associated with autoimmune retinal degeneration broadens the group of proteins related with these entities.Translational relevancePatients with anti-recoverin, anti-GCAP1, anti-Rab6A, and anti-HSP27 AAbs represented diverse clinical phenotypes, so the presence of disease-associated AAbs provides important information for molecular diagnosis.
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Project description:Paraneoplastic syndromes associated with prostate cancer that cause visual disturbances are rare. We present the case of a 71 year old man with a history of adenocarcinoma of the prostate who developed cancer associated retinopathy concomitant with small cell transformation. This represents an unusual paraneoplastic syndrome that may be progressive and irreversible, requiring prompt diagnosis and treatment to preserve visual function and guide further oncological care.
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Project description:The established association between inflammatory bowel disease and colorectal cancer underscores the importance of inflammation in colon cancer development. On the basis of evidence that hemostatic proteases are powerful modifiers of both inflammatory pathologies and tumor biology, gene-targeted mice carrying low levels of prothrombin were used to directly test the hypothesis that prothrombin contributes to tumor development in colitis-associated colon cancer (CAC). Remarkably, imposing a modest 50% reduction in circulating prothrombin in fII+/- mice, a level that carries no significant bleeding risk, dramatically decreased adenoma formation following an azoxymethane/dextran sodium sulfate challenge. Similar results were obtained with pharmacologic inhibition of prothrombin expression or inhibition of thrombin proteolytic activity. Detailed longitudinal analyses showed that the role of thrombin in tumor development in CAC was temporally associated with the antecedent inflammatory colitis. However, direct studies of the antecedent colitis showed that mice carrying half-normal prothrombin levels were comparable to control mice in mucosal damage, inflammatory cell infiltration, and associated local cytokine levels. These results suggest that thrombin supports early events coupled to inflammation-mediated tumorigenesis in CAC that are distinct from overall inflammation-induced tissue damage and inflammatory cell trafficking. That prothrombin is linked to early events in CAC was strongly inferred by the observation that prothrombin deficiency dramatically reduced the formation of very early, precancerous aberrant crypt foci. Given the importance of inflammation in the development of colon cancer, these studies suggest that therapeutic interventions at the level of hemostatic factors may be an effective means to prevent and/or impede colitis-associated colon cancer progression.
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Project description:PURPOSETo describe a series of patients with molecularly confirmed mutation in BEST1 causing Best disease but with unilateral clinical manifestation.DESIGNRetrospective observational case series.METHODSSETTINGMoorfields Eye Hospital and Great Ormond Street Hospital, London (United Kingdom).PATIENTSFive patients (10 eyes) with uniocular manifestation of BEST1 mutation causing Best disease were ascertained retrospectively from the clinical and genetic databases.MAIN OUTCOME MEASURESPatients had full ophthalmologic examination, color fundus photography, fundus autofluorescence imaging, spectral-domain optical coherence tomography, and detailed electrophysiological assessment. Genetic testing was performed.RESULTSAll cases had a clinical appearance typical of and consistent with Best disease at various stages, except that the presentation was unilateral. The reduced electrooculogram light rise was bilateral and in the context of normal electroretinograms therefore indicates generalized dysfunction at the level of the retinal pigment epithelium.CONCLUSIONSMutation in BEST1 has variable penetrance and expressivity, and can be uniocular. The clinical and electrophysiological features described assist targeted mutational screening and alert to the potential diagnosis even when there is an atypical unilateral presentation.
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