IDK1 is a rat monoclonal antibody against hypoglycosylated bone sialoprotein with application as biomarker and therapeutic agent in breast cancer skeletal metastasis.

Changes in glycosylation are salient features of cancer cells. Here, we report on the diagnostic and therapeutic properties of IDK1, an antibody against tumour associated, hypoglycosylated bone sialoprotein (hypo-BSP). The affinity of the rat monoclonal antibody IDK1 for hypo-BSP, as determined by microscale thermophoresis, was three orders of magnitude higher than for mature BSP, whereas the mouse monoclonal antibody used had similar affinity for both BSP forms. IDK1 showed no activity against the proliferation or migration of normal or cancer cells growing in vitro. In vivo, however, IDK1 caused dose-dependent regression of soft tissue and skeletal lesions in nude rats harbouring human MDA-MB-231 cells. At optimal dose, 80% of the treated rats showed complete remission of all tumour lesions. Analysis of BSP expression in vitro by fluorescence-activated cell sorting (FACS) and immunocytochemistry showed basal levels of this protein, which were visible only in a fraction of these cells. Cells of the metastatic cell lines MDA-MB-231 and PC-3 were more often positive for hypo-BSP. In addition, there was co-expression of both forms in some cells, but almost no co-localization; rather, hypo-BSP was present in the nucleus, and mature BSP was detected extra-cellularly. Normal osteoblasts and osteoclasts were negative for hypo-BSP. Breast cancer tissue, however, showed strong expression of mature BSP, which was present intra-cellularly as well as in vesicles outside cells. Hypo-BSP was present mainly in lesions from skeletal sites, thus explaining the antineoplastic activity of IDK1, which was high in lesions growing in the vicinity of the skeleton but low in lesions growing subcutaneously. Finally, hypo-BSP was detected in specimens from breast cancer patients, with a significantly greater intensity in skeletal metastases as compared to the respective primary cancers. In conclusion, IDK-1 is an antibody with diagnostic and therapeutic applications in skeletal metastases of breast cancer.

Homoarginine Associates with Zonulin and Tryptophan - Findings in a High-Risk Cohort of Patients Carrying an AICD.

BACKGROUND: Homoarginine (hArg) is known to have an impact on nitric oxide (NO) metabolism. It seems to increase NO generation and/or availability, thereby enhancing endothelial function. In addition, hArg is connected to energy metabolism since the key enzyme, L-arginine-glycine amidinotransferase (AGAT) for hArg synthesis in the kidneys, is also involved in the synthesis of energy metabolites like guanidinoacetate. Former studies indicate that low levels of hArg are linked to cardiovascular disease and increased all-cause mortality. METHODS: This study investigated the dependence of plasma hArg on various biochemical and clinical factors in 229 patients carrying an automatic, implantable cardioverter/defibrillator (AICD) using multiple linear regression analysis (Generalized Linear Model, GLM). RESULTS: GLM revealed a highly significant, positive association between hArg and zonulin (p < 0.001). hArg was also positively correlated with tryptophan (p = 0.004), BMI (p = 0.02), and body weight (p = 0.02). Patients with hsCRP above 10 mg/L had significantly lower hArg concentrations than patients with hsCRP ≤ 10 mg/L. CONCLUSIONS: The highly significant positive association of hArg with zonulin is a novel finding which may indicate a different meaning of circulating versus local (gut) zonulin. Therefore, further experimental and clinical investigation is needed to explore this association, focusing on possible pathophysiological pathways and the role of circulating zonulin levels in cardiovascular disease. The positive correlation of hArg and Trp also deserves further research because both amino acids might have a protective effect on cardiovascular disease by inhibition of the enzyme alkaline phosphatase. Eventually, our study associates low hArg concentrations with chronic low-grade inflammation and parameters of malnutrition in cardiovascular high-risk patients.

Plasma Zonulin and its Association with Kidney Function, Severity of Heart Failure, and Metabolic Inflammation.

BACKGROUND: The tight junction regulator zonulin has attracted clinical attention as a biomarker of increased gastrointestinal permeability. Recent work also suggests zonulin to represent a general regulator of tissue barriers and a player in metabolic inflammation. Here, we investigated the associations of zonulin with chronic heart failure (CHF), kidney function, and metabolic inflammation. METHODS: Using multiple linear regression (Generalized Linear Model), this study determined the association of plasma zonulin with different laboratory and clinical parameters in 225 patients carrying automatic implantable cardioverters/defibrillators (AICD) for primary or secondary prevention. In another 115 patients with diastolic or systolic CHF, we investigated a possible relationship between zonulin and CHF severity. RESULTS: In the AICD cohort, zonulin associated inversely with serum creatinine (p = 0.013), carboxymethyl-lysine calprotectin (p < 0.001), and kynurenine (p = 0.009) and positively with homoarginine (p < 0.001). In the subgroup with type-2 diabetes (T2D) (n = 51), zonulin increased significantly with high-sensitivity CRP (p = 0.014). In the CHF cohort, we found a highly significant rise of NT-proBNP, but not of zonulin with NYHA functional classes I-IV or other parameters of CHF severity. CONCLUSIONS: The inverse associations of zonulin with creatinine and markers of cardio-vascular risk (high CMLcalprotectin and kynurenine, low homoarginine) are novel findings that need further experimental and clinical clarification. Our study indicates zonulin involvement in metabolic inflammation in T2D, but no association with disease status in CHF.

Modeling of oxidized PTH (oxPTH) and non-oxidized PTH (n-oxPTH) receptor binding and relationship of oxidized to non-oxidized PTH in children with chronic renal failure, adult patients on hemodialysis and kidney transplant recipients.

BACKGROUND: The biological properties of oxidized and non-oxidized PTH are substantially different. Oxidized PTH (oxPTH) loses its PTH receptor-stimulating properties, whereas non-oxidized PTH (n-oxPTH) is a full agonist of the receptor. This was described in more than 20 well published studies in the 1970(s) and 80(s). However, PTH oxidation has been ignored during the development of PTH assays for clinical use so far. Even the nowadays used third generation assay systems do not consider oxidation of PTH We recently developed an assay to differentiate between oxPTH and n-oxPTH. In the current study we established normal values for this assay system. Furthermore, we compare the ratio of oxPTH to n-oxPTH in different population with chronic renal failure: 620 children with renal failure stage 2-4 of the 4C study, 342 adult patients on dialysis, and 602 kidney transplant recipients. In addition, we performed modeling of the interaction of either oxPTH or n-oxPTH with the PTH receptor using biophysical structure approaches. RESULTS: The children had the highest mean as well as maximum n-oxPTH concentrations as compared to adult patients (both patients on dialysis as well as kidney transplant recipients). The relationship between oxPTH and n-oxPTH of individual patients varied substantially in all three populations with renal impairment. The analysis of n-oxPTH in 89 healthy control subjects revealed that n-oxPTH concentrations in patient with renal failure were higher as compared to healthy adult controls (2.25-fold in children with renal failure, 1.53-fold in adult patients on dialysis, and 1.56-fold in kidney transplant recipients, respectively). Computer assisted biophysical structure modeling demonstrated, however, minor sterical- and/or electrostatic changes in oxPTH and n-oxPTH. This indicated that PTH oxidation may induce refolding of PTH and hence alters PTH-PTH receptor interaction via oxidation induced three-dimensional structure alteration of PTH. CONCLUSION: A huge proportion of circulating PTH measured by current state-of-the-art assay systems is oxidized and thus not biologically active. The relationship between oxPTH and n-oxPTH of individual patients varied substantially. Non-oxidized PTH concentrations are 1.5 - 2.25 fold higher in patients with renal failure as compared to health controls. Measurements of n-oxPTH may reflect the hormone status more precise. The iPTH measures describes most likely oxidative stress in patients with renal failure rather than the PTH hormone status. This, however, needs to be demonstrated in further clinical studies. © 2013 S. Karger AG, Basel.

Treatment of bone metastasis induced by MDA-MB-231 breast cancer cells with an antibody against bone sialoprotein.

The extracellular bone matrix protein bone sialoprotein (BSP) is considered to play an important role in the pathogenesis of lytic skeletal lesions which are associated with severe morbidity in breast, prostate or lung cancer patients. In addition to in vitro studies, nude rats were implanted with 10(5) MDA-MB-231 cells transfected with GFP into a small branch of the femoral artery. Osteolytic lesions of the respective hind leg were detected by X-ray and CT analysis as well as by immunohistochemistry. Exposure of MDA-MB-231GFP cells in vitro to an antibody against BSP (0-400 microg/ml) decreased proliferation, colony formation and migration of these cells by up to 95, 83 and 89 T/C%, respectively. In nude rats, pre-incubation of MDA-MB-231GFP cells prior to inoculation (25-100 microg/ml) reduced the mean osteolytic lesion size to 22 T/C% after 90 days of observation (p<0.05). Treatment of overt lytic metastasis with the anti-BSP antibody (10 mg/kg) resulted in a significantly smaller mean lesion size of 57 T/C% at the end of the observation period (p<0.05) as well as in new bone formation. Immunohistochemical analysis revealed the presence of BSP in MDA-MB-231GFP cells and in vessel endothelium cells during processes such as migration and invasion. In conclusion, an anti-BSP antibody decreased proliferation, colony formation and migration of MDA-MB-231GFP cells in vitro and reduced osteolysis besides inducing bone formation in a nude rat model.

Relaxin as an additional protective substance in preserving and reperfusion solution for liver transplantation, shown in a model of isolated perfused rat liver.

Reperfusion injury is a problem in organ transplantation. Relaxin causes vessel dilation and inhibition of platelet and mast cell activation. The study investigates the protective effect of relaxin on liver tissue against cell damage during organ preservation and reperfusion. Liver transplantation was simulated in a model of isolated perfused rat liver. Relaxin was applicated during reperfusion and/or preservation. To quantify cell damage, we examined the perfusate for malonyldialdehyde (MDA) and myeloperoxidase activity (MPO), and liver tissue underwent immunohistochemical study. Relaxin as an additional substance in preserving/reperfusion solution decreases MPO and MDA levels in the perfusate and immunohistochemical study. Relaxin seems to have a protective effect against cell damage in ischemia and reperfusion injury.

Characterization of a rat model with site-specific bone metastasis induced by MDA-MB-231 breast cancer cells and its application to the effects of an antibody against bone sialoprotein.

Metastasis into the skeleton is a serious complication of certain neoplastic diseases such as breast, prostate and lung cancer, but the reasons for this osteotropism are poorly understood. Our aim was to establish a physiologically relevant animal model that is characterized by osteolytic lesions confined to the hind leg of nude rats. For this purpose, we injected 1x10(5) MDA-MB-231 human breast cancer cells transfected with GFP into the superficial epigastric artery, which is an anastomosing vessel between the femoral and iliac arteries. As assessed with the aid of X-rays, computed tomography and immunohistochemisty, osteolytic lesions occurred exclusively in the femur, tibia and fibula of the animals. The tumor take rate was 93% in a series of 96 rats and the increase in lesion size was observed up to 110 days after tumor cell inoculation. When applying this animal model to the effects of an antibody against bone sialoprotein (BSP), a significantly reduced osteolytic lesion size was observed after preincubation of cells (2 hr, 600 microg/ml anti-BSP) prior to intra-arterial tumor cell injection resulting in 19 T/C% at day 60 after tumor implantation (p < 0.05). In addition, the osteolytic lesion size was also significantly reduced after s.c. treatment of the animals with the antibody (20 mg/kg anti-BSPx3 within 5 days after tumor implantation), resulting in 30 T/C% at day 60 after tumor cell implantation (p < 0.05). In conclusion, the novel rat model for site-specific osteolytic lesions provides in vivo evidence that preincubation of MDA-MB-231GFP cells and treatment of rats after tumor implantation with an antibody against BSP significantly reduces the size of lytic lesions in bone.

Analysis of human bone sialoprotein in normal and pathological tissues using a monoclonal antibody (BSP 1.2 mab).

Bone sialoprotein (BSP), a phosphorylated and sulphated glycoprotein that is expressed by mineralized connective tissues is also produced in tumors that metastasize to bone. To facilitate studies of BSP expression in normal and pathological human tissues a monoclonal antibody (BSP 1.2 mab) was raised against human bone BSP. BSP 1.2 mab was shown by ELISA assays to recognize the epitope "DEYSY" (amino acids 279-283) that is conserved in mammalian BSP sequences. However, whereas the antibody recognized recombinant BSPs expressed in bacteria, it did not recognize native forms of rat or pig BSP in which the first tyrosine of the DEYSY peptide sequence appears to be modified. Immunostaining of embryonic human tibiae and calvariae with BSP 1.2 mab showed strong reaction in osteoblasts and osteocytes with relatively weak staining of the bone matrix, suggesting that the BSP 1.2 mab epitope is partially masked in the bone matrix. BSP 1.2 mab also stained osteosarcoma cells and normal trophoblastic cells in the placenta in areas of microcrystalline deposits. Cancer cells in primary breast tumors, lymph nodes, and secondary bone metastases from individual patients were stained strongly by BSP 1.2 mab. Although BSP 1.2 mab also stained breast cancer carcinoma cell lines and SaOS2 osteosarcoma cells, biosynthesis of radiolabelled BSP could not be demonstrated in breast cancer cells. Notably, the staining of BSP in the breast cancer cells was diffuse contrasting the punctate staining, typical of secreted proteins, in SaOS2 cells. These studies, therefore, have identified a unique epitope in human BSP recognized by a monoclonal antibody, BSP 1.2 mab, which can be used for the unequivocal identification of BSP in normal and pathological human tissues.

S-relaxin as a predictor of preterm delivery in women with symptoms of preterm labour.

OBJECTIVE: To evaluate whether serum relaxin (S-relaxin) can predict spontaneous delivery before 34 weeks of gestation in high risk pregnancies. DESIGN: A prospective cohort study. SETTING: Calculated sample size was reached over a two-year period, during which 9507 women gave birth. Of these, 157 healthy women were eligible for the study as they were admitted with symptoms of delivery before 34 weeks of gestation. Ninety-three women were included. Overall participation rate was 59%. POPULATION: Healthy women with singleton pregnancies with symptoms of delivery before 34 weeks of gestation. METHODS: S-relaxin was measured using a standard sandwich ELISA. MAIN OUTCOME MEASURES: End points were preterm delivery before 34 weeks of gestation and delivery within three days from initiation of symptoms. The best possible prediction of preterm delivery was established using logistic regression for risk factors individually associated with preterm delivery before 34 weeks of gestation. S-relaxin was dichotomised to obtain best possible fit and then entered into the model. The same analyses were done for delivery within three days. RESULTS: Median S-relaxin levels varied significantly in the women with preterm prelabour rupture of membranes (PPROM) (316 pg/mL), contractions (222 pg/mL) or ripe cervices (203 pg/mL) (P < 0.05). S-relaxin above the 80th centile (> or = 300 pg/mL) was associated with an increased risk of preterm delivery [crude OR = 4.8; (95% CI: 1.9-12)]. Likelihood ratio of a positive test is 2.6 (1.5-4.9) and S-relaxin resulted in a post-test probability of preterm delivery of 0.72, compared with a pre-test probability of 0.49. S-relaxin contributed to the identification of delivery within three days [adj. OR = 11 (95% CI: 1.8-64)]. CONCLUSION: S-relaxin may be a useful predictor in women with symptoms of delivery before 34 weeks of gestation.