Increased fibroblast growth factor-like autoantibodies in serum from a subset of patients with cancer-associated hypercalcemia

Endothelial cell autoantibodies in predicting declining renal function, end-stage renal disease, or death in adult type 2 diabetic nephropathy

Albuminuria is a strong predictor of diabetic nephropathy chronic kidney disease outcomes. Yet, therapeutic albuminuria-lowering has not consistently translated into a reduction in clinical events suggesting the involvement of additional pathogenic factors. Our hypothesis is that anti-endothelial cell autoantibodies play a role in development and progression in diabetic nephropathy. We determined anti-endothelial cell antibody (AECA) bioactivity in protein A-elutes of baseline plasma in 305 participants in the VA NEPHRON-D study, a randomized trial of angiotensin receptor blocker (ARB) or dual ARB plus angiotensin-converting enzyme inhibitor therapy in type 2 diabetes with proteinuric nephropathy. Thirty-eight percent (117/305) of participants had significantly reduced endothelial cell survival ( ≤80%) in the IgG fraction of plasma. A VA NEPHRON-D primary endpoint [end-stage renal disease (ESRD), significant reduction in estimated glomerular filtration rate, or death] was experienced by 58 individuals. In adjusted Cox regression analysis, there was a significant interaction effect of baseline anti-endothelial cell-mediated cell survival and albuminuria on the hazard rate (HR) for primary composite endpoint (P = 0.017). Participants lacking strongly inhibitory antibodies with albuminuria ≥1 g/g creatinine had a significantly increased primary event hazard ratio, 3.41 - 95% confidence intervals (CI 1.84-6.33; P < 0.001) compared to those lacking strongly inhibitory antibodies with lower baseline albuminuria ( <1 g/g creatinine). These results suggest that anti-endothelial cell antibodies interact significantly with albuminuria in predicting the composite endpoint of death, ESRD, or substantial decline in renal function in older, adult type 2 diabetic nephropathy.

Anti-neurotrophic effects from autoantibodies in adult diabetes having primary open angle glaucoma or dementia

AIM

To test for anti-endothelial and anti-neurotrophic effects from autoantibodies in subsets of diabetes having open-angle glaucoma, dementia, or control subjects.

METHODS

Protein-A eluates from plasma of 20 diabetic subjects having glaucoma or suspects and 34 age-matched controls were tested for effects on neurite outgrowth in rat pheochromocytoma PC12 cells or endothelial cell survival. The mechanism of the diabetic glaucoma autoantibodies' neurite-inhibitory effect was investigated in co-incubations with the selective Rho kinase inhibitor Y27632 or the sulfated proteoglycan synthesis inhibitor sodium chlorate. Stored protein-A eluates from certain diabetic glaucoma or dementia subjects which contained long-lasting, highly stable cell inhibitory substances were characterized using mass spectrometry and amino acid sequencing.

RESULTS

Diabetic primary open angle glaucoma (POAG) or suspects (n = 20) or diabetic dementia (n = 3) autoantibodies caused significantly greater mean inhibition of neurite outgrowth in PC12 cells (p < 0.0001) compared to autoantibodies in control diabetic (n = 24) or non-diabetic (n = 10) subjects without glaucoma (p < 0.01). Neurite inhibition by the diabetic glaucoma autoantibodies was completely abolished by 10 μM concentrations of Y27632 (n = 4). It was substantially reduced by 30 mM concentrations of sodium chlorate (n = 4). Peak, long-lasting activity survived storage ×5 years at 0-4°C and was associated with a restricted subtype of Ig kappa light chain. Diabetic glaucoma or dementia autoantibodies (n = 5) caused contraction and process retraction in quiescent cerebral cortical astrocytes effects which were blocked by 5 μM concentrations of Y27632.

CONCLUSION

These data suggest that autoantibodies in subsets of adult diabetes having POAG (glaucoma suspects) and/or dementia inhibit neurite outgrowth and promote a reactive astrocyte morphology by a mechanism which may involve activation of the RhoA/p160 ROCK signaling pathway.

Basic fibroblast growth factor predicts cardiovascular disease occurrence in participants from the veterans affairs diabetes trial

AIM

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality in adults with type 2 diabetes mellitus. The aim of the present study was to test whether plasma basic fibroblast growth factor (bFGF) levels predict future CVD occurrence in adults from the Veterans Affairs Diabetes Trial (VADT).

METHODS

Nearly 400 veterans, 40 years of age or older having a mean baseline diabetes duration of 11.4 years were recruited from outpatient clinics at six geographically distributed sites in the VADT. Within the VADT, they were randomly assigned to intensive or standard glycemic treatment, with follow-up as much as seven and one-half years. CVD occurrence was examined at baseline in the patient population and during randomized treatment. Plasma bFGF was determined with a sensitive, specific two-site enzyme-linked immunoassay at the baseline study visit in all 399 subjects and repeated at the year 1 study visit in a randomly selected subset of 215 subjects.

RESULTS

One hundred and five first cardiovascular events occurred in these 399 subjects. The best fit model of risk factors associated with the time to first CVD occurrence (in the study) over a seven and one-half year period had as significant predictors: prior cardiovascular event [hazard ratio (HR) 3.378; 95% confidence intervals (CI) 3.079-3.807; P < 0.0001), baseline plasma bFGF (HR 1.008; 95% CI 1.002-1.014; P = 0.01), age (HR 1.027; 95% CI 1.004-1.051; P = 0.019), baseline plasma triglycerides (HR 1.001; 95% CI 1.000-1.002; P = 0.02), and diabetes duration-treatment interaction (P = 0.03). Intensive glucose-lowering was associated with significantly decreased hazard ratios for CVD occurrence (0.38-0.63) in patients with known diabetes duration of 0-10 years, and non-significantly increased hazard ratios for CVD occurrence (0.82-1.78) in patients with longer diabetes duration.

CONCLUSION

High level of plasma bFGF is a predictive biomarker of future CVD occurrence in this population of adult type 2 diabetes.

Anti-endothelial and anti-neuronal effects from auto-antibodies in subsets of adult diabetes having a cluster of microvascular complications

AIMS

To test autoantibodies from subsets of diabetes with painful neuropathy, maculopathy and nephropathy for effects in neurons.

METHODS

Protein-A eluates from plasma of 27 diabetic and 19 age-matched controls were tested for effects on endothelial cell survival, and neurite outgrowth in rat pheochromocytoma PC12 cells. Painful diabetic neuropathy or control autoantibodies were compared for binding to PC12-derived heparan sulfate proteoglycans. The mechanism of the effects from pathologic autoantibodies was investigated by changes in intracellular calcium in endothelial cells, whole cell current in neurons, or using the Rho kinase inhibitor Y27632.

RESULTS

Autoantibodies from diabetic patients with maculopathy, nephropathy, and painful neuropathy (n=5) caused significantly greater mean inhibition of neurite outgrowth (p<0.005) than diabetic or control patients with fewer or no complications (n=30). Painful diabetic autoantibodies (3 μg/mL) bound neuronal heparan sulfate proteoglycan (HSPG) more than autoantibodies from diabetic or control subjects without painful neuropathy (p<.0001). Inhibition of PC12 neurite outgrowth by the painful neuropathy antibodies was completely prevented by 1 μM concentrations of Y27632.

CONCLUSION

These results suggest anti-endothelial and anti-neuronal effects from auto-antibodies in a subset of diabetic patients with a cluster of microvascular complications.

Recurrent macular edema and stroke syndrome in type 1 diabetes mellitus with potent endothelial cell inhibitory autoantibodies

OBJECTIVE

To describe a case of type 1 diabetes mellitus with recurrent macular edema and stroke in association with potent endothelial cell inhibitory autoantibodies.

METHODS

The clinical, radiologic, and biochemical data from the study patient are presented, as is the bioactivity in endothelial cells from the immunoglobulin G fraction of the patient's serum.

RESULTS

A 52-year-old man with a 15-year history of poorly controlled type 1 diabetes mellitus had diabetic autonomic neuropathy, gastroparesis, depression, macular edema, proliferative retinopathy, diabetic nephropathy, refractory hypertension, and transient ischemic attacks that progressed to recurrent strokes despite aspirin therapy. Magnetic resonance imaging of the brain showed multi-focal, bilateral ischemic infarcts consistent with recurrent stroke affecting small vessels. The patient's serum contained endothelial cell inhibitory autoantibodies; the titer doubled during a 2-year period when the patient required repeated focal laser to treat macular edema and experienced transient ischemic attacks. The IgG autoantibodies induced stress fiber formation and apoptosis in endothelial cells and inhibited neurite outgrowth in rat pheochromocytoma PC12 cells.

CONCLUSIONS

Low concentrations of purified autoantibodies (1-2 μg/mL) induce endothelial cell contraction in vitro, suggesting a role for autoantibodies in modulating endothelial cell permeability, which may affect multiple target organs. Potent IgG autoantibodies may be a useful marker (with a possible pathophysiologic role) in an unusual syndrome characterized by poorly controlled diabetes, hypertension, dementia, and recurrent small-vessel stroke.

Autoantibodies in type 2 diabetes induce stress fiber formation and apoptosis in endothelial cells

CONTEXT

Macular edema contributes to visual impairment, and albuminuria is associated with increased cardiovascular mortality in adults with type 2 diabetes mellitus. These microvascular complications result from increased capillary leakage of plasma proteins whose causation is not completely understood.

OBJECTIVE

The objective of the present study was to test whether plasma from type 2 diabetes with maculopathy/albuminuria or control subjects contains autoantibodies that can induce apoptosis or activate Rho kinase (ROCK) in endothelial cells.

DESIGN

A cohort of Veterans Affairs Diabetes Trial adults (>40 yr of age) was randomized to standard vs. intensive glycemic treatment lasting 5-7.5 yr.

SETTING

The study was conducted in outpatient clinics.

PATIENTS

Case and age-matched control subjects who differed for the baseline presence of significant diabetic maculopathy and/or progression to macro-albuminuria were included in the study.

INTERVENTION

Pharmacological and lifestyle interventions in the Veterans Affairs Diabetes Trial generally resulted in substantially improved glycemic, blood pressure, and lipid levels.

RESULTS

Autoantibodies from patients with macular edema or progression to albuminuria potently induced caspase-dependent apoptosis in endothelial cells (up to 60%), whereas IgG from age-matched normal plasma caused much less apoptosis (<10%; P < 0.0001). The active inhibitory autoantibodies triggered stress fiber formation in endothelial cells likely through the activation of Rho guanosine 5'-triphosphatase, which could be nearly completed inhibited by 10 microm Y27632, a specific ROCK inhibitor.

CONCLUSIONS

These results suggest that autoantibodies from a subset of advanced type 2 diabetes may contribute to diabetic vascular complications by activating ROCK, inducing stress fiber formation and apoptosis in endothelial cells.

Endothelial cell inhibitory autoantibodies are associated with laser photocoagulation in adults from the Veterans Affairs Diabetes Trial

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen that does not normally circulate, but increases in microalbuminuric adult type 2 diabetes mellitus. Earlier work indicated an unexpected association between low levels of plasma bFGF immunoreactivity and the subsequent 4-year need for laser treatment in 172 patients from the Veterans Affairs Diabetes Trial (mean: age, 59 years; diabetes duration, 11 years; baseline hemoglobin A(1c), 9.5%). In the present study, we tested for an association between endothelial cell inhibitory autoantibodies in plasma and the need for laser treatment. Inhibitory activity in endothelial cells from the immunoglobulin G fractions of plasma was significantly associated (P = .002) with low plasma bFGF immunoreactivity. There was a significant association (P = .003) between endothelial cell inhibitory autoantibodies in baseline plasma and the time to occurrence of first laser treatment after 4 years of study treatment. After adjusting for other risk factors, endothelial cell inhibitory activity greater than 90% vs less than or equal to 90% (hazard ratio, 0.2; P = .003) and low-density lipoprotein cholesterol concentration (hazard ratio, 0.98; P = .02) were each significant predictors of the time to first postrandomization laser occurrence. These results suggest that circulating autoantibodies inhibitory in endothelial cells may contribute to the need for laser treatment in adult men with advanced type 2 diabetes mellitus. Among the possible risk factors evaluated, baseline insulin use was the only variable significantly inversely (P = .02) associated with the baseline occurrence of inhibitory endothelial cell autoantibodies. It could not be determined whether insulin use may decrease the occurrence of endothelial cell inhibitory autoantibodies in advancing adult type 2 diabetes mellitus.

Low plasma basic fibroblast growth factor is associated with laser photocoagulation treatment in adult type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen that does not normally circulate. Yet plasma bFGF-like bioactivity was increased in association with persistent microalbuminuria and retinopathy in adult type 2 diabetes mellitus. In the present study, we tested whether plasma bFGF immunoreactivity (IR) could predict the need for laser treatment of diabetic retinopathy in a baseline subset of advanced type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial (mean: age, 59 years; diabetes duration, 11 years; baseline glycosylated hemoglobin, 9.5%). Plasma bFGF-IR was determined with a sensitive and specific 2-site enzyme-linked immunoassay in 172 patients at the baseline visit. Results were dichotomized at 4.5 pg/mL, the upper limit in healthy men. There was an unexpected significant association between low baseline plasma bFGF-IR level and the interim (4 years) need for laser treatment. First laser treatment was significantly more likely to be required in patients with low compared with high baseline bFGF (19% vs 6%, P = .03 for the difference). After adjusting for clinical risk factors, low vs high bFGF (hazard ratio [HR], 5.01; P = .012), duration of diabetes (HR, 1.05; P = .050), and low-density lipoprotein cholesterol concentration (HR, 0.98; P = .027) were all significantly associated with time to first laser occurrence. These and our prior results suggest that low plasma bFGF-IR may be a marker for the presence of anti-endothelial cell autoantibodies that may contribute to the need for laser photocoagulation treatment in adult men with advanced type 2 diabetes mellitus.

Neurotrophic effects of fibroblast growth factor-like autoantibodies in serum from three patients with breast cancer

Basic fibroblast growth factor (FGF) promotes branching neuritogenesis and survival in rat hippocampal neurons in vitro. Basic FGF is a broad spectrum mitogen which does not normally circulate, but increases in serum from a variety of cancers. In prior work, we described spontaneously-occurring fibroblast growth factor-like autoantibodies in serum from a subset of breast cancer patients with neurological complications. The FGF-like autoantibodies mimicked the potent endothelial cell growth-promoting activity of bFGF yet had remarkably increased stability (activity survived storage at 0-4 degrees C for up to 5 years). In the present study we tested whether FGF-like autoantibodies from breast cancer sera is neurotrophic or neuroprotective. We now report that FGF-like autoantibodies (2-3 microg/mL) from breast cancer sera promoted neuritogenesis in DIV 12 embryonic day 18 rat hippocampal neurons and neurite extension in undifferentiated rat pheochromocytoma PC12 cells. The FGF-like autoantibodies from a breast cancer patient with lupus were unique in protecting rat hippocampal neurons from glutamate-induced cell loss and promoting long-lasting neurite extension and survival in PC-12 cells (up to 25 days in vitro). Breast cancer sera FGF-like autoantibodies induced large sustained increases in inward cationic current associated with depolarization in hippocampal neurons that exceeded the electrophysiological effects of substantial concentrations of basic FGF. These results suggest that differences in potency or other unknown factors contribute to whether subsets of FGF-like autoantibodies from breast cancer sera exhibit long-lasting neurotrophic and neuroprotective effects or an early neurotrophic effect followed by accelerated late neuron death.

Breast cancer cell-derived fibroblast growth factor 2 and vascular endothelial growth factor are chemoattractants for bone marrow stromal stem cells

OBJECTIVE

Recent efforts by the scientific community to characterize the complex interplay between different cell types involved in the development of tumors have led us to investigate the roles of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) in the development of breast cancer.

METHODS

Using modified Boyden chamber assays, we measured the in vitro migration effect on murine mesenchymal stem cells (MSCs). Additionally, we assayed for the presence of receptors for these growth factors on MSCs, and for the presence of VEGF and FGF2 in breast cancer-conditioned media. We measured the change in migration of MSCs toward breast cancer when we depleted these growth factors from breast cancer-conditioned media. Further, we conducted a series of standard curve migration assays for basal media supplemented with physiologic concentrations of VEGF and FGF2.

RESULTS

Analysis of gene expression and protein analysis demonstrated the expression of FGF2 and VEGF by the breast cancer cells, and the presence of VEGF (FLK1) and FGF2 receptors on the MSCs. We also demonstrated a reduction in migration when we antibody-depleted VEGF and FGF2 from breast cancer-conditioned media. Additionally, we found the physiologic concentrations of VEGF and FGF2 at 12 and 15 ng/mL, respectively.

CONCLUSIONS

We demonstrate that VEGF and FGF2 induce migration of MSCs are secreted by breast cancer cells, their receptors are present on MSCs, and depletion of these growth factors reduces migration, and are therefore 2 relevant growth factors for MSC migration toward breast cancer cells.

[Antireceptor and antichannel autoantibodies]

This review of literature concerns the different autoantibodies directed against membrane receptors and ion channels. The target antigens, the associated pathologies, the pathogenesis and the methods of detection of these autoantibodies will be addressed. Some of these autoantibodies are thought to be closely related to the auto-immune disease whereas for some others their pathogenesis role is still unclear. Overall, the roles of antibodies are different between diseases, but the presence of such autoantibodies support the basis of intervening immunotherapy, antibody titers predicted the activity of the diseases and some of them are very specific and become the useful markers for the diagnosis. Some autoantibodies are detected routinely as the antiacetylcholine receptor, voltage-gated potassium and calcium channels autoantibodies whereas most of them are detected very rarely and only by specialized laboratories. This review will be divided in three parts with the following classification: the first group of autoantibodies directed against membrane receptors included receptors with an enzymatic activity (mostly tyrosine kinase) with one transmembrane domain, receptors associated to G protein with seven transmembrane domains, ion channels and receptors associated to the membrane by the glycosylphosphatidylinositol and the second group of intracellular receptor autoantibodies directed to the estrogens, androgens, lamin and kinesin receptors.

Antigen binding of human IgG Fabs mediate ERK-associated proliferation of human breast cancer cells

Serum-circulating antibody can be linked to poor outcomes in some cancer patients. To investigate the role of human antibodies in regulating tumor cell growth, we constructed a recombinant cDNA expression library of human IgG Fab from a patient with breast cancer. Clones were screened from the library with breast tumor cell lysate. Sequence analysis of the clones showed somatic hypermutations when compared to their closest VH/VL germ-line genes. Initial characterizations focused on five clones. All tested clones displayed stronger binding to antigen derived from primary breast cancers and established breast cancer cell lines than to normal breast tissues. In vitro functional studies showed that four out of five tested clones could stimulate the growth of MDA-MB-231 breast cancer cell lines, and one out of five was able to promote MCF-7 cell growth as well. Involvement of ERK2 pathway was observed. By 1H-NMR spectra and Western blot analysis, it was evident that two tested antibody Fabs are capable of interacting with sialic acid. Our study suggests a possible role for human antibody in promoting tumor cell growth by direct binding of IgG Fab to breast tumor antigen. Such studies prompt speculation regarding the role of serum antibodies in mediating tumor growth as well as their contribution to disease progression.

Effect of basic fibroblast growth factor on growth regulation in Bel-7402 cell line

AIM

To investigate whether bFGF regulates p21^WAF1 expression of Bel-7402 cell line via PI3K/PKB pathway.

METHODS

32P incorporation assay. The expression of p21^WAF1-mRNA was assessed by RT-PCR. The expression of p21^WAF1 protein was detected by Western blot. Cell cycle analysis was performed on a FACScan.

RESULTS

Both membrane and cytosol activity of PKB in Bel-7402 cell which were treated with bFGF (25 mg/L) reached the peak at 10 min. p21^WAF1 mRNA level was upregulated and peaked at 1 h (5.5 fold induction). Correspondingly, p21^WAF1 expression was increased and peaked at 2 h (2.2 folds of reduction). Wortmannin efficiently inhibited the activity of PKB (P <0.05), but not the level of p21^WAF1 mRNA and the expression of p21^WAF1 protein. FCM analysis showed bFGF induced S-phase entry (0.14±0.01→0.28±0.01, P <0.01), which was inhibited by wortmannin effectively (0.28±0.01→0.22±0.01, P <0.01).

CONCLUSION

bFGF stimulates the proliferation of Bel-7402 cell line via PI3K/PKB pathway, and modulates p21^WAF1 expression through separating signaling pathways.