Background: CD22 has emerged as an attractive target for the treatment of B-cell malignancies because (i) CD22 shows high surface expression on most mature and precursor B-cell malignancies, (ii) it ...is rapidly internalized after ligand binding, and (iii) it is readily replenished after internalization due to a substantial intracellular pool. CD22 has been engaged therapeutically using CAR-T cells (Frey, 2018), immunotoxins (Wayne, 2018), or Antibody-drug-conjugates (Kantarjian, 2016). Preclinical data, however, has exclusively been generated using immune compromised mice which is a major drawback of current animal models.
Goal: We aimed to establish a syngeneic, murine lymphoma model expressing the human CD22 antigen under physiologic promoter control to test CD22-targeted therapies in an immune competent background.
Methods/Results: A CD22 chimera (h/mCD22) was designed as human on the outside and murine on the inside. Engaged by the CD22-targeted immunotoxin Moxetumomab pasudotox (Moxe) in vitro, h/mCD22 successfully transports Moxe which exclusively targets the human CD22 to the cytosol of murine cells resulting in a dose dependent cytotoxicity. By cross-breeding BL6 mice expressing h/mCD22 as a transgene (BL6tm(h/mCD22)Eng) and the BL6λ-myc mouse strain, we generated mice that spontaneously develop h/mCD22-positive lymphoma. Three primary lymphomas were isolated from distinct mice and each serially transplanted into BL6tm(h/mCD22)Eng mice. Stable engraftment and tumor cell growth was established after subcutaneous (sc) as well as intravenous (iv) injection. Tumor cells isolated from sc tumors, however, were substantially smaller than tumor cells isolated from bone marrow (BM), Spleen (SPL), or lymph nodes (LN) after iv injection. Correlating with the approximately 2-fold redcued cell surface of the smaller sc tumor cells, surface CD22 was reduced by 2-fold. Importantly, sc tumors were infiltrated by less than 1% immune cells, while myc-driven lymphoma in men commonly present with substantial tumor-infiltrating immune cells. Resembling human disease, the systemically growing tumors after iv injection were infiltrated by 20% myeloid cells in BM, by 5% in LN, and by 10 % in SPL and were infiltrated by 0.5% T-cells in BM, by 30% in LN, and by 7% in SPL. Testing Moxe against the three distinct primary murine B-NHL models in vivo, we found Moxe to be more active, the longer high blood levels were maintained, reflecting results from studies in immune compromised models (Müller, 2016). Moxe given as 4 doses intraperitoneally every day for 5 days achieved stable disease in one and reduced tumor burden by more than 10-fold and by more than 50-fold in two other systemic mouse models.
Conclusion: By cross-breeding h/mCD22-transgenic and λ-myc expressing mouse strains, we generated primary aggressive B-cell lmyphoma expressing h/mCD22. The lymphomas engraft in h/mCD22-transgenic BL6 mice and iv but not sc injected tumors recapitulate the immune infiltration found in human myc-translocated B-NHL. Our unique models provide a valuable platform to test treatment modalities targeting human CD22 in more relevant models of disease.
No relevant conflicts of interest to declare.
Delayed graft function (DGF) occurs in a significant proportion of deceased donor kidney transplant recipients and was associated with graft injury and inferior clinical outcome. The aim of the ...present multi-center study was to identify the immunological and non-immunological predictors of DGF and to determine its influence on outcome in the presence and absence of human leukocyte antigen (HLA) antibodies. 1,724 patients who received a deceased donor kidney transplant during 2008-2017 and on whom a pre-transplant serum sample was available were studied. Graft survival during the first 3 post-transplant years was analyzed by multivariable Cox regression. Pre-transplant predictors of DGF and influence of DGF and pre-transplant HLA antibodies on biopsy-proven rejections in the first 3 post-transplant months were determined by multivariable logistic regression. Donor age ≥50 years, simultaneous pre-transplant presence of HLA class I and II antibodies, diabetes mellitus as cause of end-stage renal disease, cold ischemia time ≥18 h, and time on dialysis >5 years were associated with increased risk of DGF, while the risk was reduced if gender of donor or recipient was female or the reason for death of donor was trauma. DGF alone doubled the risk for graft loss, more due to impaired death-censored graft than patient survival. In DGF patients, the risk of death-censored graft loss increased further if HLA antibodies (hazard ratio HR=4.75,
< 0.001) or donor-specific HLA antibodies (DSA, HR=7.39,
< 0.001) were present pre-transplant. In the presence of HLA antibodies or DSA, the incidence of biopsy-proven rejections, including antibody-mediated rejections, increased significantly in patients with as well as without DGF. Recipients without DGF and without biopsy-proven rejections during the first 3 months had the highest fraction of patients with good kidney function at year 1, whereas patients with both DGF and rejection showed the lowest rate of good kidney function, especially when organs from ≥65-year-old donors were used. In this new era of transplantation, besides non-immunological factors, also the pre-transplant presence of HLA class I and II antibodies increase the risk of DGF. Measures to prevent the strong negative impact of DGF on outcome are necessary, especially during organ allocation for presensitized patients.
Bitter taste receptors (T2Rs) are G protein‑coupled receptors originally detected in the gustatory system. More recently, T2Rs have been shown to be expressed in extra‑oral cells eliciting ...non‑gustatory functions. Emerging evidence has suggested a potential role for T2R signaling in diverse pathophysiological conditions, including cancer. -The aim of the present study was to evaluate the expression of T2R14 in pancreatic ductal adenocarcinoma (PDAC) and to assess its involvement in the anticancer effects induced by apigenin, a natural ligand of T2R14. For this purpose, T2R14 expression was explored in PDAC tumor tissue and tumor‑derived cell lines. Using the cell lines expressing the highest levels of T2R14, its effects on chemoresponsiveness and migration upon activation with apigenin were investigated
. To the best of our knowledge, the present study was the first to confirm the expression of the T2R family member T2R14 in PDAC. Patients with relatively high levels of T2R14 expression exhibited significantly prolonged overall survival compared with that of patients with low T2R14 expression. Furthermore, novel functions for apigenin were revealed; notably, apigenin was shown to elicit cytotoxic, anti‑migratory and chemosensitizing effects to 5‑fluoruracil (5‑FU) and to 5‑FU, leucovorin, irinotecan and oxaliplatin in pancreatic cancer cells. In conclusion, the present study extended the evidence for the anticancer effects of apigenin and strongly indicated the functional relevance of T2R14 in PDAC, even though their respective underlying pathways appear to be independent of each other.
The outcome after living kidney donation was assumed to be comparable to that of the general population. However, recent register studies reveal negative changes in kidney function, quality of life ...and fatigue. Avoiding methodological issues of previous studies, the Safety of the Living Kidney Donor (SoLKiD) cohort study analyzed the outcome of donors in a multicenter and interdisciplinary fashion. Donor data were collected pre-donation and two-, six- and 12-months post-donation in 20 German transplantation centers. Primary parameters were kidney function, quality of life, and fatigue. Secondary endpoints were blood pressure, hemoglobin, hemoglobin A1c, body mass index, depression and somatization. Parameters were analyzed with non-parametric statistical tests and a mixed model regression for changes in time, their clinical relevance and interaction encompassing 336 donors with mean age of 52 years. Most of the physical secondary parameters, depression, and quality of life showed little or no changes and regained their pre-donation level. Kidney function decreased significantly with a 37% loss of glomerular filtration rate and an increase of donors with chronic kidney disease stage 3 from 1.5% pre-donation to about 50%. Donors consistently showed increased fatigue and somatization. Mental fatigue increased from 10.6% to 28.1%. The main influencing factors for decreased kidney function and increased fatigue were their respective pre-donation levels, and donor age for kidney function and subject stress level in fatigue. Thus, our study showed that a significant number of donors developed clinically relevant changes in physical and mental health and emphasizes the urgent need to inform potential donors about these risks.
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Receptor‐targeted therapies have become standard in the treatment of various lymphomas. In view of its unparalleled specificity for the malignant B‐cell clone, the B‐cell receptor (BCR) on B cell ...lymphoma cells is a potential therapeutic target. We have used two BCR epitope mimicking peptides binding to the Burkitt's lymphoma cell lines CA46 and SUP‐B8. We proved their functionality by demonstrating calcium flux and BCR‐mediated endocytosis upon peptide receptor binding. Toxicity experiments in vitro
via cross‐linking of the BCR with tetramerized epitope mimics lead to apoptosis in both cell lines but was far more effective in SUP‐B8 cells. We established a SUP‐B8‐based disseminated Burkitt's lymphoma model in NOD/SCID mice. Treatment of tumor‐bearing mice with tetramerized epitope mimics had significant anti‐tumor effects in vivo. We conclude that peptide‐mediated, BCR‐targeted therapy is a promising approach which may be explored and further developed for application in highly aggressive lymphoma.
Over the last years, living kidney donation (LKD) has been established for patients with endstage renal failure as an alternative to post mortem donation, which is limited by organ scarcity and long ...lasting waiting periods. From an ethical perspective, the increase in LKD requires that donors' physical, psychological, and social harm has to be minimized as much as possible and the risk should not exceed the generally expected consequences of nephrectomy. Despite of numerous, mainly retrospective studies about the postoperative outcome of LKD over the last years from different countries, it becomes apparent that there is a lack of comprehensive prospective multicenter research in this field worldwide. Therefore, the main aim of the study is to examine the physical and psychosocial outcome of living kidney donors in a prospective design before and after transplantation in an interdisciplinary approach (surgery, nephrology, psychosocial medicine).
The goal of the study is to investigate such aspects as the impact of gender- and age-specific factors on LKD outcome, donor outcome in correlation to the health status of the recipient, the medical and psychosocial risk of a healthy subject undergoing the LKD procedure. The study is carried out as a nationwide multicenter study. All adult living kidney donors with sufficient knowledge in the German, Russian, or Turkish language, informed consent, and place of residence in Germany are included. In a naturalistic design (cohort study), clinical data and self-report measures (questionnaires) of 320 donors are collected before and 8 weeks, 6 and 12 months after donation. Primary outcome parameters are the kidney function (estimated GFR) and the quality of life (SF-36) of the donor. Secondary outcome parameters are data about physical (e.g., wound healing, blood pressure) and psychosocial (fatigue, depression, anxiety, somatization) outcome after donation.
Previous studies on the postoperative outcome of living kidney donors have methodological limitations and/or were carried out in countries with different healthcare systems, e.g. United States, Norway, Canada, United Kingdom. Thus, results cannot be generalized and are not particularly applicable to the risks of mainly caucasian living kidney donors in the German healthcare system. The study design overcomes these disadvantages in that it provides a prospective multicenter design.
German Clinical Trials Register DRKS00006552 (22 September 2014).
Abstract 3924
Targeted therapies in terms of monoclonal antibodies have become standard in the treatment of various lymphomas. Albeit being more specific than conventional therapy, the used ...antibodies target surface receptors both present on polyclonal and monoclonal hematopoietic cells. Due to its specificity for the malignant B-cell clone the B-cell receptor (BCR) is an ideal therapeutic target in lymphoma therapy. Moreover, using peptides has several advantages over whole antibodies: reduced immunogenicity, better epitope mimicry and tissue penetration, easier synthesis and more favourable pharmacokinetics (no uptake into the reticulo-endothelial system). Peptides mimicking the epitope recognized by lymphoma BCRs have therefore been praised as promising therapeutic tools for years (Lam, West J Med., 1993) but a proof-of-concept has only been published recently in mice bearing subcutaneous A20 lymphoma (Palmieri et al., Blood, 2010).
In the current study, we have established a human cell line-derived disseminated Burkitt′s lymphoma model (SUP-B8) in NOD/SCID mice by intravenous injection. Our active principle was the tetramerized BCR binding peptide YSFEDLYRRGGK-biotin (termed T-peptide, Renschler et al., PNAS, 1994) which was applied intravenously on day (d) 12, 14, 16 and 19 after injection of the tumor cells, respectively. The therapeutic efficacy was evaluated in comparison to several control groups (tetramerized control peptide (termed C-peptide, RDYSYERLFGGK-biotin), vehicle (0.8% ACN in water, 200μl/d) and untreated animals). Tumor cell engraftment was monitored via daily surveillance of disease symptoms, FACS (anti-human lambda, CD19, anti-murine CD45) and fluorescence-based in vivo imaging system (FI, Kodak FX, Alexa750 labeled anti-human CD45) on days 12 and 21.
SUP-B8 engrafted predominantly in the bone marrow (BM, take rate = 100%) and marrow infiltration increased in untreated mice between start and end of therapy from 1 ± 0.4% (d 12) to 39.8 ± 9.4% (d 21). Other sites of engraftment were subcutis (38%) and spleen (8%). The examined compounds were well tolerated in tumor-bearing mice, no acute toxicity could be observed and maximal body weight loss was below 15%. Treatment of xenograft mice with the tetramerized BCR-binding peptide significantly reduced bone marrow infiltration compared to controls (T-peptide 8.1 ± 4.6%, C-peptide: 32.8 ± 8%, p=0.037, vehicle: 30.5 ± 7.9%, p=0.029). Considering the short half-life of uncoupled peptides and the injection schedule every second day, this is a remarkable reduction. For further optimization of this promising therapeutic approach we plan to couple peptides to effector molecules via acid labile linkers; this is based on the evidence that confocal imaging of Burkitt lymphoma cell lines showed the processing of specific BCR binding peptides in acidic organelles of the cell.
In summary, we conclude that BCR targeted peptide-based therapy is a feasible method with remarkable therapeutic results in vivo and future studies will focus on coupling specific peptides to appropriate effector molecules or combinational therapeutic approaches using conventional chemotherapeutics.
No relevant conflicts of interest to declare.
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