Sugar Free: Novel Immunotherapeutic Approaches Targeting Siglecs and Sialic Acids to Enhance Natural Killer Cell Cytotoxicity Against Cancer

Natural Killer (NK) cells are cytotoxic lymphocytes that play a key role in the immune system, targeting and destroying invading pathogens and malignantly transformed cells. Evading NK cell-mediated immunosurveillance is therefore critical to facilitating cancer cell survival and metastasis. Signals from a range of inhibitory and activating receptors located on the NK cell surface regulate NK cell cytotoxicity. Recently, attention has turned to the role of hypersialylated tumor cell surfaces in mediating immune-evasion of NK cells. Two inhibitory sialic acid-binding immunoglobulin-like lectin (Siglec) receptors are expressed by NK cells: Siglec-7 and Siglec-9. The abundance of sialic acids on tumor cell surface is hypothesized to regulate NK cell-mediated cytotoxicity by interacting with Siglec-7 and Siglec-9, causing a dampening of NK cell activation pathways. Targeting Siglec-7 and Siglec-9, or the sialic acid coated tumor cell surface is therefore being investigated as a novel therapeutic approach to enhance the NK cell response against cancer. In this review we report on the currently published documentation of the role for Siglec-7 and Siglec-9 receptors on NK cells and their ligands expressed by tumor cells. We also discuss the strategies currently explored to target Siglec-7, Siglec-9 and the sialylated tumor cell surface as well as the impact abrogation of these interactions have on NK cell cytotoxicity against several cancer types

Molecular specificities of NK cell-mediated recognition of human tumor cells

Natural killer (NK) cells have been implicated in tumor immune surveillance and can reject transformed cells expressing ligands for activating NK cell receptors and low levels of HLA class I. Although NK cells are well known for their ability to kill tumor cells, relatively few studies have addressed the molecular specificity of NK cell-mediated recognition of freshly isolated human tumor cells. The rational for conducting such studies is based on the fact that tumor cell lines display altered molecular expression compared to their origin. In this thesis, we have assessed the role for NK cells in solid and hematological malignancies. We show that freshly isolated metastatic ovarian carcinoma (OC) cells express low levels of HLA class I. In one patient, we identified a genomic HLA class I haplotype loss that was associated with a HLA-A2 restricted Her2/neu specific T cell response. The low HLA class I levels, in combination with the presence of ligands for activating NK cell receptors, resulted in a significant killing of the metastatic OC cells by allogeneic NK cells, while sparing normal cells. Experiments masking activating NK cell receptors revealed a dominant role for the DNAM-1 receptor with a minor contribution from the NKG2D receptor. Studies of the receptor repertoire and functional integrity of NK cells associated to the tumor in vivo substantiated a role for DNAM-1 since a marked loss of DNAM-1 as well as 2B4 and CD16 were observed and resulted in significantly reduced natural cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC) against autologous carcinoma cells. The DNAM-1 loss was likely caused by chronic ligand exposure, since physical interactions between the receptor and its ligand CD155 induced down-regulation. Suppressed NK cell function due to loss of DNAM-1 and NKG2D expression was also identified in the bone marrow and blood of patients with myelodysplastic syndromes (MDS). Relative to NK cells in peripheral blood, bone marrow-derived NK cells associated to the tumor cells displayed a more severe loss of the two receptors as well as a reduced effector cell function. The receptor loss was most prominent in patients with more than 5% blasts in the bone marrow, suggesting that poor NK cell function may be associated with an increased risk of progression to acute myeloid leukemia (AML). Tumor cells may also evade NK cell-mediated lysis by up-regulation of HLA-E that inhibits NK cell activity through signaling via the CD94/NKG2A receptor. Drugs have been used to manipulate the NK cell receptor ligand repertoire on tumor cells to render them more susceptible to NK cells. Selenite, a highly reactive oxidative agent, is known to selectively kill tumor cells when used in high concentrations. We show that selenite also reduced the expression of HLA-E and rendered the tumor cells more susceptible to killing by CD94/NKG2A expressing NK cells. Given the emerging evidence for NK cell-mediated tumor immune surveillance, our data indicate that tumor progression may be promoted by perturbed activating NK cell receptor repertoires and poor function of tumor-associated NK cells. The data imply that OC could be targeted by NK cell-based immunotherapy and that MDS patients having more than 5% blasts in the bone marrow could be considered as potential candidates for NK cell-based immunotherapy. Data also indicate that selenite may be used to improve the results of NK cell-based immunotherapies by rendering HLA-E expressing tumor cells more susceptible to NK cells. Thus, a better comprehension of the molecular specificity of NK cells targeting fresh human tumor cells and the role for combinatorial treatments can hopefully advance NK cell-based immunotherapies

Influence of storage time on samples obtained by piston sampler

(1) Jordparametrar som påverkas av långvarig lagring; (2) Orsaker till att lagringstiden påverkar jordparametrar; (3) Resultat från undersökningar utförda på SGI; (4) Funderingar kring problemet med långtidslagrade prover; (5) Riktlinjer för fortsatta försök; Bilagor: (1) Sammanställning av utförda CRS-försök; (2) Kompressionskurvor; (3) Sammanställninga av rutinundersökningar; (4) Rutinundersökninga

Om hur livet kan förändras : En studie om yngre demenssjuka personer

Demenssjukdomar är mycket utbrett och hör till de stora folksjukdomarna i Sverige. Den mest vanliga är Alzheimers sjukdom. Ofta då vi tänker på sådana tragiska livsöden är det lätt att relatera dem till människor som är i åldern sextiofem år eller äldre. Dessvärre finns det även personer som drabbas i ett tidigare skede i livet vilket kan vara redan vid femtio års ålder. Syftet med denna studie är att studera livssituationen för dessa ”yngre” personer med demens eller demensliknande symptom boende på en gruppbostad. Vi kommer dessutom att diskutera förändringen av livssituation i dagsläget jämfört med innan denna verksamhet startades. I vår kvalitativa studie har vi genomfört tre intervjuer med anhöriga till dementa personer som bor på detta gruppboende samt en fokusgruppsintervju med fyra medarbetare på detsamma. Detta har vi gjort med anledning av att få en förståelse för hur livet kan se ut för demenssjuka personer både innan och efter inflyttning till den aktuella boendeverksamheten. I analysen av våra informanters utsagor har vi bland annat utgått från Goffmans teori och begreppet stigma. Denna teori anser vi vara mest lämpad i relation till vår studie. I våra intervjuer med anhöriga samt medarbetare framkom tydligt hur livssituationen ser ut i dagsläget jämfört med tiden innan inflyttning till det aktuella boendet. Samtliga var enhälligt överens om att livssituationen i dagsläget är mer tillfredställande nu, jämfört med hur den var innan. Vår slutsats av informanternas beskrivning är att det skett en positiv förändring gällande de demenssjukas omvårdnad, boendemiljö samt sociala nätverk

Clinical study on osteoporosis in ankylosing spondylitis

ABSTRACT Ankylosing spondylitis (AS) is a disease characterized by chronic inflammation and osteoproliferation in the spine, leading to bony fusion (ankylosis) of the sacroiliacal joints, the growth of bony spurs (syndesmophytes) between the vertebras and impairment of back-mobility. Paradoxically AS patients also have an increased risk of osteoporosis and vertebral fractures. In this cross-sectional study on 210 included AS patients (New York criteria) from West Sweden we found that osteoporosis and vertebral fractures were common but often not diagnosed or treated. Osteoporosis (WHO definition) was found in 21 % and osteopenia in 44 % of patients 50 years or older and bone mineral density (BMD) below expected range for age was found in 5% of patients younger than 50 years. Totally 42 vertebral fractures were diagnosed in 24 patients (12%). Osteoporosis was associated with old age, long disease duration, advanced chronic AS related changes in the spine, impairment of back- mobility, history of coxitis, glucocorticoid use, elevated inflammatory parameters, low BMI and menopause. Vertebral fractures were associated with old age, long disease duration, advanced chronic AS related changes in the spine, impairment of back-mobility, poor self-estimated general health, smoking, menopause and low BMD. The osteoproliferation in AS can cause artifactual increase of lumbar BMD when measured in anteroposterior (AP) projection with dual-energy x-ray absorptiometry (DXA). Lumbar BMD can also be measured in the vertebral bodies using lateral projection. Comparing lateral with AP DXA we found that lateral lumbar DXA was more sensitive in detecting low BMD, less affected by the osteoproliferation in AS and more closely associated with vertebral fractures. Combining AP and lateral lumbar DXA also allows for the estimation of volumetric BMD (vBMD). There is a lack of biomarkers for osteoproliferation and osteoporosis in AS. We analysed serum levels of the following biomarkers for bone metabolism in relation to disease activity, back mobility, osteoproliferation and BMD: Wingless proteins (Wnt-3a, Wnt-5a), Dickkopf-1 (Dkk-1), sclerostin, soluble receptor activator for nuclear factor-κΒ ligand (sRANKL) and osteoprotegerin (OPG). We found that the AS patients in comparison with healthy controls had significantly higher serum levels of Wnt-3a, but lower serum levels of sclerostin and sRANKL. Elevated serum levels of Wnt-3a were associated with osteoproliferation and impairment of back-mobility, independent of age, suggesting that Wnt-3a could be a marker for the osteoproliferative process. High CRP was associated with lower levels of the Wnt inhibitors Dkk-1 and sclerostin. BMD of femoral neck was negatively correlated with Wnt3a and OPG and positively correlated with sRANKL in the univariate analyses, but positively associated with sclerostin after adjusting for age in multiple regression. Osteoproliferation and impairment of back mobility and function were in addition associated with smoking. To study peripheral bone microarchitecture in relation to osteoproliferation, fractures and vBMD of the spine 69 male AS patients were randomized to undergo assessment with High Resolution peripheral Quantitative Computed Tomography (HRpQCT) of the ultra-distal radius and tibia and QCT of the lumbar spine. We found strong correlations between trabecular vBMD in lumbar spine and radius and tibia, indicating coupling of trabecular bone loss in axial and peripheral skeleton. Low lumbar vBMD, vertebral fractures and osteoproliferation were in addition associated with deterioration of the bone microarchitecture of the peripheral skeleton. In lumbar spine decreasing trabecular vBMD was associated with increasing cortical vBMD, suggesting that cortical bone is appositioned as part of the osteoproliferative process meanwhile trabecular bone is lost in the vertebral bodies. AS is closely related to inflammatory bowel disease (IBD) and subclinical intestinal inflammation has been detected in many AS patients. We measured fecal calprotectin, a marker for neutrophil inflammation, to indirectly study the prevalence of gut inflammation in AS. We found elevated levels of fecal calprotectin in 68% of the AS patients, without association with gastrointestinal symptoms. Fecal calprotectin was higher in users of non-steroidal anti-inflammatory drugs (NSAIDs) in a dose dependent manner, but lower in patients treated with methotrexate or TNFα-blockers. No association was found between fecal calprotectin and BMD. ISBN: 978-91-628-8618-

Body composition measurements and risk of hematological malignancies : A population-based cohort study during 20 years of follow-up

High body mass index (BMI) is associated with development of hematological malignancies (HMs). However, although BMI is a well-established measurement of excess weight, it does not fully reflect body composition and can sometimes misclassify individuals. This study aimed at investigating what body composition measurements had highest association with development of HM. Body composition measurements on 27,557 individuals recorded by healthcare professionals as part of the Malmo Diet and Cancer study conducted in Sweden between 1991-1996 were matched with data from national registers on cancer incidence and causes of death. Cox regression models adjusted for age and sex were used to test the association between one standard deviation increments in body composition measurements and risk of HM. During a median follow-up of 20 years, 564 persons developed an HM. Several body composition measurements were associated with risk of developing an HM, but the strongest association was found for multiple myeloma (MM). Waist circumference (HR 1.31, p = 0.04) and waist-hip ratio (HR 1.61, p = 0.05) had higher risk estimates than BMI (HR 1.18, p = 0.07) for MM. In conclusion, our study shows that measurements of abdominal adiposity better predict the risk of developing HM, particularly MM, compared to BMI