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The insulin-like growth factor type 1 receptor (IGF-1R) plays a key role in the development and progression of cancer; however, therapeutics targeting it have had disappointing results in the clinic. As a receptor tyrosine kinase (RTK), IGF-1R is traditionally described as an ON/OFF system, with ligand stabilizing the ON state and exclusive kinase-dependent signaling activation. Newly added to the traditional model, ubiquitin-mediated receptor downregulation and degradation was originally described as a response to ligand/receptor interaction and thus inseparable from kinase signaling activation. Yet, the classical model has proven over-simplified and insufficient to explain experimental evidence accumulated over the last decade, including kinase-independent signaling, unbalanced signaling, or dissociation between signaling and receptor downregulation. Based on the recent findings that IGF-1R 'borrows' components of G-protein coupled receptor (GPCR) signaling, including β-arrestins and G-protein-related kinases, we discuss the emerging paradigm for the IGF-1R as a functional RTK/GPCR hybrid, which integrates the kinase signaling with the IGF-1R canonical GPCR characteristics. The contradictions to the classical IGF-1R signaling concept as well as the design of anti-IGF-1R therapeutics treatment are considered in the light of this paradigm shift and we advocate recognition of IGF-1R as a valid target for cancer treatment. [ABSTRACT FROM AUTHOR]

Protein-coding genes comprise only 3% of the human genome, while the genes that are transcribed into RNAs but do not code for proteins occupy majority of the genome. Once considered as biological darker matter, non-coding RNAs are now being recognized as critical regulators in cancer genome. Among the many types of non-coding RNAs, microRNAs approximately 20 nucleotides in length are best characterized and their mechanisms of action are well generalized. microRNA exerts oncogenic or tumor suppressor function by regulation of protein-coding genes via sequence complementarity. The expression of microRNA is aberrantly regulated in all cancer types, and both academia and biotech companies have been keenly pursuing the potential of microRNA as cancer biomarker for early detection, prognosis, and therapeutic response. The key involvement of microRNAs in cancer also prompted interest on exploration of therapeutic values of microRNAs as anticancer drugs and drug targets. MRX34, a liposome-formulated miRNA-34 mimic, developed by Mirna Therapeutics, becomes the first microRNA therapeutic entering clinical trial for the treatment of hepatocellular carcinoma, renal cell carcinoma, and melanoma. In this review, we presented a general overview of microRNAs in cancer biology, the potential of microRNAs as cancer biomarkers and therapeutic targets, and associated challenges. [ABSTRACT FROM AUTHOR]

The human cathelicidin antimicrobial protein-18 and its C terminal peptide, LL-37, displays broad antimicrobial activity that is mediated through direct contact with the microbial cell membrane. In addition, recent studies reveal that LL-37 is involved in diverse biological processes such as immunomodulation, apoptosis, angiogenesis and wound healing. An intriguing role for LL-37 in carcinogenesis is also beginning to emerge and the aim of this paper was to explore if and how LL-37 contributes to the signaling involved in tumor development. To this end, we investigated the putative interaction between LL-37 and growth factor receptors known to be involved in tumor growth and progression. Among several receptors tested, LL-37 bound with the highest affinity to insulin-like growth factor 1 receptor (IGF-1R), a receptor that is strongly linked to malignant cellular transformation. Furthermore, this interaction resulted in a dose-dependent phosphorylation and ubiquitination of IGF-1R, with downstream signaling confined to the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-pathway but not affecting phosphatidylinositol 3 kinase/Akt signaling. We found that signaling induced by LL-37 was dependent on the recruitment of β-arrestin to the fully functional IGF-1R and by using mutant receptors we demonstrated that LL-37 signaling is dependent on β-arrestin-1 binding to the C-terminus of IGF-1R. When analyzing the biological consequences of increased ERK activation induced by LL-37, we found that it resulted in enhanced migration and invasion of malignant cells in an IGF-1R/β-arrestin manner, but did not affect cell proliferation. These results indicate that LL-37 may act as a partial agonist for IGF-1R, with subsequent intra-cellular signaling activation driven by the binding of β-arrestin-1 to the IGF-1R. Functional experiments show that LL-37-dependent activation of the IGF-1R signaling resulted in increased migratory and invasive potential of malignant cells. [ABSTRACT FROM AUTHOR]

Purpose: Uveal melanoma has a high mortality rate due to a high incidence of metastasis (up to 50%) which preferentially occurs in the liver. Conventional chemotherapy being the only therapeutic option today against metastatic uveal melanoma, has not proved to be effective. Therefore, new molecular targets important for malignant phenotype of uveal melanoma have to be found to design efficient pharmacologic agents. Experimental Design: We previously reported data indicating that the insulin-like growth factor-1 receptor (IGF-IR) is a metastasis predictor as well as a therapeutic target for uveal melanoma. In the present study, we made use of the cyclolignan picropodophyllin (PPP), which is an inhibitor of the IGF-IR. Result: We showed that PPP efficiently block growth and viability of uveal melanoma cells in cultures and causes tumor regression in xenografted mice. In addition, treatment with PPP inhibited several mechanism involved in metastasis, including tumor cells adhesion to extracellular matrix proteins, activity and expression of matrix metalloproteinase 2, and cell migration as well as invasion through basement membranes and endothelial cell layer. Furthermore, PPP significantly delayed established of uveal melanoma tumor and drastically reduced the indence of liver metastasis in mice. Conclusions: Our data suggest that IGR-IR is crucial for growth and survival as well as invasion and metastasis of uveal melanoma cells. Targeting this receptor may therefore comprise a strategy to treat ongoing disease (today incurable) as well as a strategy to prevent development of metastases in patients with primary disease. [ABSTRACT FROM AUTHOR]

β-Arrestin1, which regulates many aspects of seven transmembrane receptor (7TMR) biology, has also been shown to serve as an adaptor, which brings Mdm2, an E3 ubiquitin ligase to the insulin-like growth factor-1 receptor (IGF-1R), leading to its proteasome-dependent destruction. Here we demonstrate that IGF-1R stimulation also leads to ubiquitination of 10-arrestin1, which regulates vesicular trafficking and activation of ERK1/2. This β-arrestin1-dependent ERK activity can occur even when the classical tyrosine kinase signaling is impaired. siRNA-mediated suppression of β-arrestin1 in human melanoma cells ablates IGF-1-stimulated ERK and prolongs the G1 phase of the cell cycle. These data suggest that 10-arrestin-dependent ERK signaling by the IGF-1R regulates cell cycle progression and may thus be an important regulator of the growth of normal and malignant cells. [ABSTRACT FROM AUTHOR]

The insulin-like growth factor-1 receptor (IGF-1R) plays important roles in physiological growth and aging as well as promoting several crucial functions in cancer cells. However, the molecular mechanisms involved in expression and down-regulation of IGF-1R are still poorly understood. Here we provide evidence that β-arrestin, otherwise known to be involved in the regulation of G protein-coupled receptors, serves as an adaptor to bring the oncoprotein E3 ubiquitin ligase MDM2 to the IGF-1R. In this way, β-arrestin acts as a crucial component in the ubiquitination and down-regulation of the receptor. Both MDM2 and β-arrestin co-immunoprecipitated with the IGF-1R. The β-arrestin isoform 1 appeared to be more strongly associated with the receptor than isoform 2, and in a molecular context it was 4-fold more efficient in inducing polyubiquitination of IGF-1R, a reaction that required the presence of β-arrestin and MDM2. Ligand stimulation accelerated IGF-1R ubiquitination. In mouse P6 cells (overexpressing human IGFIR) absence of β-arrestin 1, but not of β-arrestin 2, blocked ubiquitination of IGF-1R. Conversely, in the two studied human melanoma cell lines both β-arrestin isoforms seemed to be involved in IGF-1R ubiquitination. However, because depletion of β-arrestin 1 almost completely eliminated degradation, and IGF-1 induced down-regulation of the receptor in these cells, whereas β-arrestin 2 only had a partial effect, β-arrestin 1 seems to the more important isoform in affecting the expression of IGF-1R. To our knowledge this is the first study demonstrating a defined molecular role of β-arrestin with direct relevance to cell growth and cancer. [ABSTRACT FROM AUTHOR]

The insulin-like growth factor (IGF-1) signalling is highly implicated in cancer. In this signalling the IGF-1 receptor (IGF-1R) is unquestionable, the predominating single factor. IGF-1R is crucial for tumour transformation and survival of malignant cell, but is only partially involved in normal cell growth. This is in part due to the interactions with oncogenes. Recent findings suggest a close interplay with the p53/MDM2 pathway. Disturbances in components in the p53/MDM2/IGF-1R network may cause IGF-1R upregulation and growth advantage for the cancer cell. Targeting of IGF-1R is more and more seen as a promising option for future cancer therapy. Single chain antibodies and small molecules with selective effects on IGF-1R dependent malignant growth are of particular interest. Forthcoming clinical trials are welcome and will indeed be the only way to evaluate the impact of IGF-1R targeting in human cancer.British Journal of Cancer (2005) 92, 2097–2101. doi:10.1038/sj.bjc.6602627 www.bjcancer.com Published online 24 May 2005 [ABSTRACT FROM AUTHOR]

The insulin-like growth factor-1 receptor (IGF-1R) is crucial for many functions in neoplastic cells, for example, antiapoptosis. Recently, we demonstrated that the cyclolignan PPP efficiently inhibited phosphorylation of IGF-1R without interfering with insulin receptor activity. PPP preferentially reduced phosphorylated Akt, as compared to phosphorylated Erk1/2, and caused apoptosis. Now, we aimed to investigate how PPP inhibits the IGF-1R tyrosine kinase (IGF-1RTK) and the PI3K/Akt apoptotic pathway. Using a baculovirus driven IGF-1RTK we found that PPP interfered with tyrosine phosphorylation in the activation loop of the kinase domain. Specifically, it blocked phosphorylation of tyrosine (Y) 1136, while sparing the two others (Y1131 and Y1135). To explore the impact of inhibition of Y1136 on Akt phosphorylation we transfected P6 cells (overexpressing IGF-1R) and malignant melanoma cells with different IGF-1R mutants, including Y1136F (tyrosine replaced by phenylalanine). Y1136F was found to strongly decrease IGF-1 stimulated phosphorylation of Akt. Conversely, Akt phosphorylation was weakly affected in the Y1131F transfectant. Taken together, our data suggest that the preferential inhibition of phosphorylated Akt, after PPP treatment, may be due to specific inhibition of Y1136. PPP was proven not to interfere directly with Akt or any of its downstream molecules in the apoptotic pathway.Oncogene (2004) 23, 7854-7862. doi:10.1038/sj.onc.1208065 Published online 30 August 2004 [ABSTRACT FROM AUTHOR]

Recently, p53 was demonstrated to affect the expression of the insulin-like growth factor 1 receptor (IGF-1R), a receptor tyrosine kinase that plays a crucial role in growth and survival of cancer cells. However, the underlying mechanisms for interaction between p53 and IGF-1R are still not fully understood. One of the challenging questions remaining to be answered is why the wildtype p53, which per se represses the transcription of the IGF-1R gene, in overexpressed form is necessary for a high IGF-1R expression. In this study, we show that inhibition of p53 causes ubiquitination and down-regulation, through increased degradation, of the IGF-1R in human malignant melanoma cells. This effect, which was independent of the p53 status (i.e., wild type or mutated), was prevented if Mdm2 was coinhibited. Similar results were obtained in UV-irradiated human melanocytes (harboring wild-type p53), in which level of the IGF-1R increased after up-regulation of p53. Interestingly, the basal ubiquitination of the IGF-1R in untreated cells also depended on Mdm2. We could prove that Mdm2 physically associates with IGF-1R and that Mdm2 causes IGF-1R ubiquitination in an in vitro assay. Taken together our data provide evidence that Mdm2 serves as a ligase in ubiquitination of the IGF-1R and thereby causes its degradation by the proteasome system. Consequently, by sequestering Mdm2 in the cell nuclei, the level of p53 may indirectly influence the expression of IGF-1R. This role of Mdm2 and p53 represents an unexpected mechanism for the regulation of IGF-1R and cell growth. [ABSTRACT FROM AUTHOR]

Systemic sclerosis is a rare autoimmune disorder with a wide spectrum of clinical manifestations and a multitude of autoantibodies that are associated with it. In the past several years, advances in serologic testing have led to research indicating important prognostic and phenotypic associations with certain subsets of autoantibodies. In particular, anti-RNA polymerase III (anti-RNAP III) has been associated with diffuse cutaneous disease, scleroderma renal crisis, a temporal relationship with malignancy, myositis, synovitis, joint contractures, and gastric antral vascular ectasia. However, anti-RNAP III has not been associated with systemic sclerosis sine scleroderma. We describe a patient with an atypical presentation of anti-RNAP III positive systemic sclerosis sine scleroderma who presented without the typical features of anti-RNAP III disease. Instead, she presented with critical digital ischemia, pulmonary arterial hypertension, gastroesophageal reflux disease, interstitial lung disease, and no clinically detectable sclerodactyly. [ABSTRACT FROM AUTHOR]

The EWS/FLI-1 fusion gene is characteristic of most cases of Ewing's sarcoma and has been shown to be crucial for tumor transformation and cell growth. In this study we demonstrate a drastic down-regulation of the EWS/FLI-1 protein, and a growth arrest, following serum depletion of Ewing's sarcoma cells. This indicates that growth factor circuits may be involved in regulation of the fusion gene product. Of four different growth factors tested, basic fibroblast growth factor (bFGF) was found to be of particular significance. In fact, upon treatment of serum-depleted cells with bFGF, expression of the EWS/FLI-1 protein and growth of the Ewing's sarcoma cells were restored. In addition, a bFGF-neutralizing antibody, which was confirmed to inhibit FGF receptor (FGFR) phosphorylation, caused down-regulation of EWS/FLI-1. Experiments using specific cell cycle blockers (thymidine and colcemide) suggest that EWS/FLI-1 is directly linked to bFGF stimulation, and not indirectly to cell proliferation. We also demonstrated expression of FGFRs in several tumor samples of Ewing's sarcoma. Taken together, our data suggest that expression of FGFR is a common feature of Ewing's sarcoma and, in particular, that the bFGF pathway may be important for the maintenance of a malignant phenotype of Ewing's sarcoma cells through up-regulating the EWS/FLI-1 protein. Oncogene (2000) 19, 4298–4301 [ABSTRACT FROM AUTHOR]

Purpose: We aimed to report a case of orbital solitary fibrous tumour (SFT) in a child and to review the relevant literature. Methods: We describe an SFT in a 13-year-old boy with a 1-month history of painless proptosis in the left eye. Results: Magnetic resonance imaging revealed a well circumscribed mass filling most of the left intraconal orbit. The lesion was excised and histopathological examination revealed a malignant SFT. Postoperative follow-up for 18 months was uneventful. Conclusions: Malignant SFT of the orbit should be included in the differential diagnosis of paediatric orbital tumours. Complete surgical excision remains the preferred method of management and the longterm prognosis is guarded. [ABSTRACT FROM AUTHOR]

Chronic lung allograft dysfunction (CLAD) limits long term survival after lung transplantation. Antibody mediated rejection (AMR) has been associated with earlier CLAD development, but studies are limited in children. Clinical AMR can exist on a spectrum from subclinical to definite AMR based on the presence of anti-HLA donor specific antibodies (DSA), allograft dysfunction, and histopathologic findings, with DSA development first to appear. This study aims to describe the relationship of elevated DSA with clinical outcomes in a single center pediatric lung transplant population. This was a single center, retrospective study. Pediatric bilateral lung transplant recipients were included from 2002-2020 if they had longitudinal HLA and lung function data for at least 6 months after transplantation. Preliminary analyses with chi-squared or Fisher's exact test for categorical variables and ANOVA or Kruskal-Wallis for continuous variables were used. DSA were detected with single-antigen bead arrays, and elevated DSA was defined as a mean fluorescence intensity level above 500. 34 patients were included: 19 with elevated DSA and 15 without. Most patients had subclinical AMR (n=10) without allograft dysfunction and two patients had definite AMR, based on the 2018 Banff consensus statement. The proportion of patients who developed CLAD was significantly higher in the elevated DSA group and had an earlier onset of CLAD. Average graft longevity and rates of acute cellular rejection, while not significant, trended towards shorter survival and higher rates of rejection in the elevated DSA group. All persistently elevated DSA were directed against HLA Class II DQ (6 of 14 patients) epitopes. Survival analysis and the significance of different HLA antigens remains ongoing. The development of persistently elevated HLA Class II DQ DSA is associated with CLAD and likely decreased survival in the pediatric lung transplant population. [ABSTRACT FROM AUTHOR]

Consolidating the information that we have on pharmacogenetics and on cytokine genetics to produce patient-oriented individualized drug regimens is an important challenge in transplantation medicine. Using a multi-variant approach based on genetic profile and other relevant clinical factors a score system may be developed to predict the severity of rejection, infection, or other complications associated with transplantation. The ultimate goal of these studies is to improve patient outcome through individualized drug regimens. [Copyright &y& Elsevier]

An increasing number of studies demonstrate the clinical impact of preformed and de novo anti-human leucocyte antigen alloantibody (HLA-Ab) in solid organ transplantation (Tx). The screening of HLA-Ab in candidates and transplant recipients has evolved over time, with continuous improvement in the sensitivity and specificity of assays for HLA-Ab detection. Furthermore, histologic markers of complement activation pathways are currently implemented in the diagnosis of antibody-mediated rejection (AMR). Therapeutic strategies, including depletion of HLA-Ab and B cells, have allowed Tx across antibody barriers, or have rescued patients with AMR. The purpose of the present review is to summarize the state-of-the-art of HLA-Ab detection, clinical significance and therapeutic strategies in pediatric solid organ Tx. [ABSTRACT FROM AUTHOR]

The complement activation demonstrated by vascular C4d deposition is used to diagnose antibody-mediated rejection (AMR) in renal allografts, but remains controversial in lung transplantation (LTX). Methods: C4d deposition was assessed by immunohistochemistry in 192 lung transplant biopsies from 32 patients. ELISA analysis was performed on 415 serum samples in those 32 temporally and rejection-grade matched LTX patients; 16 patients developed HLA-Ab, while the other 16 patients remained negative. The specificity of C4d staining was further compared in 18 additional LTX patients without HLA-Ab or acute cellular rejection (ACR), but in the presence of CMV-pneumonitis or reperfusion injury. Results: Specific subendothelial C4d deposition was seen in 5 of 16 (31%) patients with HLA-Ab and was absent in 16 patients without HLA-Ab (P<0.05). All patients with specific C4d deposition exhibited donor-specific HLA-Ab. There were 13 patients with bronchiolitis obliterans syndrome in the group of 16 HLA-Ab positive patients, versus 2/16 in ELISA-negative patients (P<0.005). One of 7 patients with CMV pneumonitis and 2 of 11 patients with reperfusion injury also showed C4d positivity (not statistically significant). Conclusions: In this study, specific subendothelial C4d deposition was a marker for the involvement of HLA-Ab in lung allograft rejection. The patchy nature, low sensitivity, and specificity of C4d staining might limit clinical use in protocol biopsies. However, in patients with decreasing pulmonary function, refractory ACR and/or HLA-Ab, specific C4d deposition may serve as a marker of coexistent AMR. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we determine whether the presence of enzyme-linked immunosorbent assay (ELISA) detected anti-human leukocyte antigen (HLA) antibodies correlates with acute and chronic rejection in pediatric heart transplantation (Tx). Forty-five patients, who had serial ELISA pre- and posttransplantation, were studied. Age at Tx was 8.2 ± 7.2 years. Acute rejection (AR) was defined as International Society for Heart and Lung Transplantation Grade ≥3a. Patients were defined as rejectors (22 cases) if they had recurrent AR or steroid-resistant AR within the first year post-Tx; the other cases (23) were defined as nonrejectors. Overall, 219 samples were analyzed. Twenty-two of the 45 had pre- or post-Tx anti-HLA antibodies: 77% in rejectors (17/22) and only 22% in nonrejectors (5/23), p = 0.0002. Pre-Tx HLA antibodies were present in 12 cases (27%). Presensitization was more frequent in rejectors (11/22, 50%) than in nonrejectors (1/23, 4%, p = 0.0005). Nineteen cases retained (9 cases) or developed (10 cases) anti-HLA antibodies post-Tx: 14 in rejectors (63.6%) and 5 in nonrejectors (21.7%), p = 0.003. Four of eight cases with coronary artery disease (50%) had preformed anti-HLA antibodies compared with 8 of 37 without coronary artery disease (25.6%) (p = 0.09). Preformed, persistent, and de novo ELISA-detected anti-HLA antibodies were correlated with first-year acute rejection profile. [Copyright &y& Elsevier]

Background: The impact of HLA-specific antibodies is not well established in the acute rejection of lung allografts. Acute rejection represents the most important risk factor for the development of chronic lung allograft dysfunction.Methods: We analyzed the pattern of HLA antibodies before and after transplantation in 54 patients, and correlated our data with the presence and frequency of high-grade and persistent-recurrent acute rejection, during the first 18 post-operative months. The diagnosis of acute rejection was based on histologic International Society for Heart and Lung Transplantation (ISHLT)-published criteria.Results: Ten of 54 patients had a positive enzyme-linked immunoassay (ELISA) post-transplantation. In 90% of ELISA-positive patients, the presence of HLA antibodies was associated with persistent-recurrent acute rejections, compared with 34% in the ELISA-negative group (p < 0.005). There were 28 high-grade acute rejection episodes in the ELISA-positive group, compared with 36 in the ELISA-negative group (p < 0.0001). The ELISA-positive patients required a greater intensity of immunosuppressive therapy. The patients with ELISA-detected anti-HLA antibodies were at least 3-fold more likely to develop high-grade acute rejection and persistent-recurrent acute rejection, and 7-fold more likely to develop multiple episodes of persistent-recurrent acute rejection, compared with ELISA-negative patients.Conclusions: ELISA-based screening for the development of HLA antibodies is a reliable method that can identify lung transplant recipients at increased risk for high-grade and persistent-recurrent acute rejection. Although bronchiolitis obliterans appears as a point of no return in the evolution of lung-transplanted patients, early detection of risk factors for acute rejection could indirectly decrease the incidence of bronchiolitis obliterans. These lung-transplanted patients may benefit from an altered strategy of immunosuppression. [Copyright &y& Elsevier]

Abstract: Human leukocyte antigen (HLA)–specific antibodies (Abs) were examined in 73 clinically stable liver transplant recipients divided into group A (n = 19; clinically tolerant), group B (n = 34; undergoing weaning, on minimal immunosuppression), and group C (n = 20; had failed drug withdrawal or weaning never attempted). Of 19 patients in group A, six (32%) had anti-HLA Abs; none were donor-specific. In contrast, 23 of 34 patients (67%) in group B and nine of 20 patients (45%) in group C exhibited anti-HLA Abs (p = 0.02). Furthermore, 15 of 19 patients in groups B and C (9/12, p = 0.01 and 6/7, p = 0.01, respectively) exhibited donor-specific anti-HLA Abs. The prevalence of donor-specific HLA Abs was significantly higher in nontolerant patients. Five years after initial evaluation, >90% (18/19) group A patients remained off immunosuppression. One of seven of these patients available for retesting exhibited donor-specific Abs. In group B, two-fourths of 34 patients (12%) weaned successfully were HLA-Ab negative; four patients who experienced rejection while undergoing weaning exhibited anti-HLA Ab initially and at 5 years. Thus, most of the liver recipients off immunosuppression lacked donor-specific alloAbs. The occurrence of these alloAbs should now be examined prospectively in a drug weaning trial. [Copyright &y& Elsevier]

Highlights from the article: Anti-HLA antibodies are capable of inducing injury by complement-independent mechanisms, including Fc-gamma receptor (Fc R) engagement. Fifty-six renal transplant patients with biopsy-proven antibody mediated rejection (AMR) were included in this study (17 early AMR and 39 late AMR; this patient group is identical to the group previously used to validate the CD64 Fc R assay). All patients exhibited anti-HLA donor specific antibodies (DSA) detected and identified by single-antigen multiplex bead array (SAB), with anti-IgG type-specific and anti-IgG1-4 subtype specific secondary antibody.

Aims Renal transplant (RTX) candidates with pre-formed anti-HLA antibody (HLA-Ab) have lower transplantation rates and increased mortality. Anti-angiotensin II type 1 receptor antibody (AT1R-Ab) has recently been associated with allograft loss and antibody-mediated rejection. The aim of the present study was to evaluate: (1) the prevalence of anti-angiotensin receptor 1 antibody (AT1R-Ab) in RTX candidates with circulating HLA-Ab and (2) AT1R-Ab response to VDS. Methods Thirty-nine patients receiving desensitization therapy had HLA-Ab levels determined by single-antigen bead array (Luminex). Mean fluorescence intensity (MFI) of the strongest HLA-Ab (immunodominant antibody -iDSA) was measured before and after therapy. A successful response was considered when iDSA decreased >50% at nadir versus pre-desensitization. Serum samples were also tested by ELISA for the presence of AT1R-Ab (U/mL after 1:50 dilution), before and after desensitization. Results A high proportion of candidates with HLA-Ab exhibited AT1R-Ab (20/39, 51%). A good response of AT1R-Ab to therapy was observed in 18/20 patients [Figure 1]: 17.4 ± 12.3 pre versus 10.9 ± 13.1 U/mL post therapy, p = 0.0009). iDSA reduction with desensitization was observed in 13/20 patients – 7996 ± 2580 pre versus 4410 ± 2695 MFI post therapy, p = 0.0001). 12/20 patients had both iDSA and AT1R-Ab reduction by therapy, 6/20 responded to AT1R-Ab only, 1/20 responded to iDSA only, and 1/20 was a non-responder. AT1R-Ab levels were more elevated in Caucasians then in African-Americans both before (20.7 ± 14.9 versus 12.3 ± 3.7 U/mL, p = 0.1), and after desensitization (14.7 ± 15.9 versus 5.2 ± 2.9 U/mL, p = 0.1). Conclusions More than half of HLA-sensitized candidates exhibit AT1R-Ab. This initial desensitization experience consistently provided substantial reductions both in HLA-Ab and AT1R-Ab levels in an unselected, highly sensitized kidney transplant candidate population. [ABSTRACT FROM AUTHOR]

Aim Systemic lupus erytematosus (SLE) is the autoimmune disease with the highest prevalence in renal transplant population. The purpose of the present study was to describe the sensitization profile in renal transplant patients with end stage renal disease due to SLE. Methods A retrospective single-center analysis in the last ten years revealed 26 all renal transplant patients with SLE - twenty females and six males. This group was matched to a 53 patient control group, with no SLE, but matched for gender and age distribution. The HLA polymorphism for -A, -B, -C, -DRB1, -DRB3/4/5, -DQB1, -DQA1, -DPB1 was performed by reverse SSO for intermediate resolution in all patients, while high resolution SBT (Sanger) was used for 12 cases. The auto-crossmatches were performed both by complement-dependent cytotoxicity, and by flowcytometry. The presence and identification of anti-HLA antibody was achieved by single-antigen bead (Luminex) assays. Results The HLA typing in SLE group has shown a higher (19/26, 73%) prevalence of HLA-DRB1–3/4/5 antigens when compared to control group (8/53, 15%, p < 0.05). Furthermore, 4 SLE patients (15%) exhibited a positive cytotoxic and flow auto-crossmatch, compared to only 1 (2%) in controls ( p < 0.01). The distribution of HLA-specific antibody was 20/26 (77%) in SLE versus 18/53 in controls (33%), p < 0.01 The class distribution in SLE group was: 19 anti-class I, and 11 anti class II, versus 11 class I and 7 class II in controls. 22 patients in SLE group exhibited anti-HLA antibody towards public epitopes resulting in a calculated PRA > 50%, while 19 SLE patients exhibited anti-HLA antibody towards public epitopes resulting in a calculated PRA > 80%. The control group had a significantly lower proportion of strong antibody towards public epitopes (4/18 and 2/18, respectively, p < 0.01). Conclusions Renal transplant patients with SLE exhibited a higher prevalence of HLA-DRB1-3/4/5 self antigens, and a higher prevalence of positive auto-crossmatches and strong HLA antibody towards public epitopes. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate anti-HLA antibody eluted from fine needle allograft biopsies. Methods Two tissue-pieces and ten core fine needle biopsies were obtained in 9 transplant patients: 7 with biopsy-proven C4d+ antibody mediated rejection (ABMR), and two without rejection; 6 kidneys, 3 livers and one combined kidney–liver transplants. Tissue pieces weight was 0.33 g and 2.24 g, respectively. The weight of core biopsy ranged from 0.004 g to 0.008 g, average 0.006 g/core. Elution was performed by an acidic method, and then eluates were tested for donor-specific anti-HLA antibody (eDSA) by Luminex in parallel with serum samples. Cluster analysis considered both theoretical and adsorption/elution proved epitopes. Results We identified eDSA in all ABMR patients (6/7 with circulating DSA), and in none of controls. There was a linear correlation between antibody strength (MFI) and tissue weight (figure), both for class I, and class II DSAs. However, since the MFI average in eluates was only in the range of hundreds, epitope clustering was the tool for eDSA identification. We noted higher MFI in liver versus kidney biopsy cores (>80% class I, >75% class II). The epitope distribution of DSA eluted from biopsy is summarized in the table and were previously described by adsorption/elution cell lines (El-Awar et al). In contrast, circulating antibodies exhibited combinations of theoretical and elution-proved epitope patterns. Conclusions Given the low amount of HLA-specific antibody eluted from fine-needle core allograft biopsy, epitope cluster analysis can be used for antibody identification, even in ABMR cases where circulating DSA cannot be documented. [ABSTRACT FROM AUTHOR]

Aim: Immune thrombocytopenia (ITP) is defined by persistent low platelet count less than 105/mm3 in the absence of other causes. The pathogeny includes anti-platelet antibodies. Platelet transfusion is rare in ITP, however may be helpful to treat life-threatening hemorrhages. Methods: Platelet and HLA-specific antibodies were detected by ELISA. Anti- HLA class I antibodies were identified by Luminex single antigen beads. HLA typing for patient and spouse were done by rSSO. Results: 72 year old female was admitted in the emergency room with confusion, extensive petechiae, purpura, echymosses, intracranial and pulmonary hemorrhages and severe thrombocytopenia (2000/mm3). Eight units of platelets were transfused, however the platelet count remained the same. Refractoriness to transfusion was assessed. Patient exhibited both platelet-specific (1a, 1b, 3a, 3b, 4a, 5a, 5b) and anti-HLA antibodies (PRA 80%), explained by only 2 specificities – HLA -A3 and w4 epitope (Fig. 1a). The HLA typing revealed HLA-A3 and B57(w4) as mismatched antigens in husband (patient had 3 pregnancies), while patient HLA was w6. The IgG subtype analysis demonstrated IgG1, which is a strong complement binder and it explained the massive and rapid platelets destruction after receiving the transfusion (Fig. 1b). Display Omitted Conclusions: The lack of post-transfusion platelet increment was caused by anti-HLA and platelet specific antibodies, as a result of pregnancy sensitization. In this dramatic case, diagnosis through alloantibody identification and HLA typing supported adequate therapy, with Rituximab and splenectomy, and patient survived a life threatening condition. [Copyright &y& Elsevier]

Aim Factors that determine histopathologic phenotype of antibody mediated heart allograft rejection (AMR) are not known. The purpose of this study was to evaluate associations between histopathology and IgG subtype of anti-HLA donor-specific antibody (DSA) in a single-center pediatric heart transplantation program. Methods We analyzed data from 66 consecutive patients with biopsy proven rejection. Serum samples were timely matched with heart allograft biopsies, which were graded for cellular rejection. DSAs were identified by single-antigen multi-bead array, both by generic IgG, and IgG1-2-3-4 subtype. Rejection was classified as ISHLT higher grade (HR, grade 2) or no/low grade (NLR, grade 1B). We compared the prevalence of IgG subclasses between those with HR and those with NLR. Results Out of 66 cases, we identified DSAs in 28 patients, while 38 were negative. In the DSA-positive group (table), 15 patients had HR and 13 patients had NLR. IgG3 subtype was more prevalent in the HR group, compared with NLR group (14/15 HR vs 1/13 NLR, p < 0.001). Furthermore, high-grade rejectors with DSA exhibited more IgG subtype combinations when compared to NLR (13/15 HR vs 3/13 NLR, p < 0.01). The positive predictive value of the presence of IgG3 subclass for HR was 93%, negative p . Conclusions The prevalence of DSAs of IgG3 subtype was significantly elevated in patients with HR. High-grade rejectors were characterized by multiple IgG subtypes, while low-grade rejectors exhibited DSAs of a single subtype (non-IgG3). The determination of the IgG subclass in DSA-positive patients may be a less invasive method for identifying patients at risk for higher grade cellular rejection. [ABSTRACT FROM AUTHOR]

The cyclolignan PPP was recently demonstrated to inhibit the activity of insulin-like growth factor-1 receptor (IGF-1R), without affecting the highly homologous insulin receptor. In addition, PPP caused complete regression of xenografts derived from various types of cancer. These data highlight the use of this compound in cancer treatment. However, a general concern with antitumor agents is development of resistance. In light of this problem, we aimed to investigate whether malignant cells may develop serious resistance to PPP. After trying to select 10 malignant cell lines, with documented IGF-1R expression and apoptotic responsiveness to PPP treatment (IC50s less than 0.1 μM), only two survived an 80-week selection but could only tolerate maximal PPP doses of 0.2 and 0.5 μM, respectively. Any further increase in the PPP dose resulted in massive cell death. These two cell lines were demonstrated not to acquire any essential alteration in responsiveness to PPP regarding IGF-1-induced IGF-1R phosphorylation. Neither did they exhibit any increase in expression of the multidrug resistance proteins MDR1 or MRP1. Consistently, they did not exhibit decreased sensitivity to conventional cytostatic drugs. Rather, the sensitivity was increased. During the first half of the selection period, both cell lines responded with a temporary and moderate increase in IGF-1R expression, which appeared to be because of an increased transcription of the IGF-1R gene. This increase in IGF-1R might be necessary to make cells competent for further selection but only up to a PPP concentration of 0.2 and 0.5 μM. In conclusion, malignant cells develop no or remarkably weak resistance to the IGF-1R inhibitor PPP.Oncogene (2006) 25, 3186–3195. doi:10.1038/sj.onc.1209339; published online 16 January 2006 [ABSTRACT FROM AUTHOR]

Background: Inflammation in the eye is often associated with aggravated ocular diseases such as uveal melanoma (UM). Poor prognosis of UM is generally associated with high potential of metastatic liver dissemination. A strong driver of metastatic dissemination is the activation of the epithelial-mesenchymal transition (EMT) regulating transcription factor ZEB1, and high expression of ZEB1 is associated with aggressiveness of UM. While ZEB1 expression can be also associated with immune tolerance, the underlying drivers of ZEB1 activation remain unclear. Methods: Transcriptomic, in vitro, ex vivo, and in vivo analyses were used to investigate the impact on clinical prognosis of immune infiltration in the ocular tumor microenvironment. A metastatic liver dissemination model of was developed to address the role of natural killer (NK) cells in driving the migration of UM. Results: In a pan-cancer TCGA analysis, natural killer (NK) cells were associated with worse overall survival in uveal melanoma and more abundant in high-risk monosomy 3 tumors. Furthermore, uveal melanoma expressed high levels of the tumor necrosis factor superfamily member 4-1BB ligand, particularly in tumors with monosomy 3 and BAP1 mutations. Tumors expressing 4-1BB ligand induced CD73 expression on NK cells accompanied with the ability to promote tumor dissemination. Through ligation of 4-1BB, NK cells induced the expression of the ZEB1 transcription factor, leading to the formation of liver metastasis of uveal melanoma. Conclusions: Taken together, the present study demonstrates a role of NK cells in the aggravation of uveal melanoma towards metastatic disease. [ABSTRACT FROM AUTHOR]

Nevus-associated lentigo maligna and lentigo maligna melanoma (NALMM) are rarely described in the literature and are considered an incidental finding. This study aimed to evaluate the frequency of NALMM and its clinicopathological features. A total of 201 histopathology reports were reviewed and among them 20% of the samples corresponded to NALMM, with females overrepresented in this group (p = 0.02). A significant association was also observed between NALMM with the presence of multiple nevi (p = 0.01), and dysplastic nevi (p = 0.04). Moreover, the risk of developing a second melanoma of nevus-associated type was 4.3 times higher in patients with NALMM. These results indicate that NALMM is more frequent than previously reported, suggesting that the associated nevus could interact or even act as a precursor for LM/LMM. Future studies with larger samples allied to techniques like confocal microscopy and molecular analysis are essential to determine this biological link between nevus and LM/LMM. [ABSTRACT FROM AUTHOR]

Statins are notorious for causing myalgia and sometimes mild elevation of CPK (creatine phosphokinase). Herein, we present a case of necrotizing autoimmune myopathy induced by statins. The patient was on therapy with atorvastatin for about six years before she started developing myalgia and mild elevation in CPK that resolved after discontinuation of therapy. Since her cardiovascular risk was high and she had hypercholesterolemia, three months after CPK levels normalization, she was re-challenged with pravastatin. Few months later, she again presented severe myalgia, weakness, and elevated CPK levels. Hence, medication was discontinued, and she undergone an extensive workup for possible causes of inflammatory myopathies that revealed necrotizing autoimmune myopathy. Our case report offers an excellent source of “identification patterns” of muscular autoimmune disease which can be easily mistaken as common side effect of a drug. [ABSTRACT FROM AUTHOR]