Albumin activates the AKT signaling pathway and protects B-chronic lymphocytic leukemia cells from chlorambucil- and radiation-induced apoptosis

mTORC1-Driven Protein Translation Correlates with Clinical Benefit of Capivasertib within a Genetically Preselected Cohort of PIK3CA-Altered Tumors

Capivasertib is a potent selective inhibitor of AKT. It was recently FDA approved in combination with fulvestrant to treat HR+, HER2-negative breast cancers with certain genetic alteration(s) activating the PI3K pathway. In phase I trials, heavily pretreated patients with tumors selected for activating PI3K pathway mutations treated with capivasertib monotherapy demonstrated objective response rates of <30%. We investigated the proteomic profile associated with capivasertib response in genetically preselected patients and cancer cell lines. We analyzed samples from 16 PIK3CA-mutated patient tumors collected prior to capivasertib monotherapy in the phase I trial. PI3K pathway proteins were precisely quantified with immuno-Matrix-Assisted Laser Desorption/Ionization-mass spectrometry (iMALDI-MS). Global proteomic profiles were also obtained. Patients were classified according to response to capivasertib monotherapy: "clinical benefit (CB)" (≥12 weeks without progression, n = 7) or "no clinical benefit (NCB)" (progression in <12 weeks, n = 9). Proteins that differed between the patient groups were subsequently quantified in AKT1- or PIK3CA-altered breast cancer cell lines with varying capivasertib sensitivity. The measured concentrations of AKT1 and AKT2 varied among the PIK3CA-mutated tumors but did not differ between the CB and NCB groups. However, analysis of the global proteome data showed that translational activity was higher in tumors of the NCB vs. CB group. When reproducibly quantified by validated LC-MRM-MS assays, the same proteins of interest similarly distinguished between capivasertib-sensitive versus -resistant cell lines. The results provide further evidence that increased mTORC1-driven translation functions as a mechanism of resistance to capivasertib monotherapy. Protein concentrations may offer additional insights for patient selection for capivasertib, even among genetically preselected patients.

SIGNIFICANCE

Capivasertib's first-in-class FDA approval demonstrates its promise, yet there remains an opportunity to optimize its use. Our results provide new evidence that proteomics can stratify genetically preselected patients on clinical benefit. Characterization of the same profile in cell lines furnishes additional validation. Among PIK3CA-altered tumors, increased mTORC1-driven translation appears to confer intrinsic resistance. Assessing mTORC1 activation could therefore prove a useful complement to the existing genetic selection strategy for capivasertib.

Untargeted metabolomics identifies indole-3-propionic acid to relieve Ang II-induced endothelial dysfunction in aortic dissection

Indole-3-propionic acid (IPA), a gut microbiota-derived metabolite of tryptophan, has been proven to fulfill an essential function in cardiovascular disease (CVD) and nerve regeneration disease. However, the role of IPA in aortic dissection (AD) has not been revealed. We aimed to investigate the role of IPA in the pathogenesis of AD and the underlying mechanisms of IPA in endothelial dysfunction. Untargeted metabolomics has been employed to screen the plasma metabolic profile of AD patients in comparison with healthy individuals. Network pharmacology provides insights into the potential molecular mechanisms underlying IPA. 3-aminopropionitrile fumarate (BAPN) and angiotensin II (Ang II) were administered to induce AD in mice, while human umbilical vein endothelial cells (HUVECs) were employed for in vitro validation of the signaling pathways predicted by network pharmacology. A total of 224 potentially differential plasma metabolites were identified in the AD patients, with 110 up-regulated metabolites and 114 down-regulated metabolites. IPA was the most significantly decreased metabolite involved in tryptophan metabolism. Bcl2, caspase3, and AKT1 were predicted as the target genes of IPA by network pharmacology and molecular docking. IPA suppressed Ang II-induced apoptosis, intracellular ROS generation, inflammation, and endothelial tight junction (TJ) loss. Animal experiments demonstrated that administration of IPA alleviated the occurrence and severity of AD in mice. Taken together, we identified a previously unexplored association between tryptophan metabolite IPA and AD, providing a novel perspective on the underlying mechanism through which IPA mitigates endothelial dysfunction to protect against AD.

Serum albumin exposure enhances cell invasiveness and paclitaxel resistance in human neuroblastoma cells, with attenuation by valeriana-type iridoid glycosides

Neuroblastoma, a prevalent extracranial solid tumor in children, arises from undifferentiated nerve cells. While tumor vasculature, often characterized by increased permeability, influences metastasis and recurrence, the direct impact of blood-borne molecules on tumor progression remains unclear. In the present study, we focused on the effect of exposure to albumin, one of the most abundant proteins in the serum, on human neuroblastoma cells. Albumin exposure elevated oxidative stress and led to mitochondria dysfunction via the activation of TGFβ and PI3K pathways, accompanied by an increase in the metastatic and invasive properties of neuroblastoma cells. Proteins relevant to the induction of autophagy were upregulated in response to prolonged albumin exposure. Additionally, pre-exposure to albumin before treatment resulted in increased resistance to paclitaxel. Two valeriana-type iridoid glycosides, patrisophoroside and patrinalloside, recently isolated from Nardostachys jatamansi significantly mitigated the effect of albumin on oxidative stress, cell invasiveness, and chemoresistance. These findings illuminate the potential role of blood-borne molecules, such as albumin, in the progression and metastasis of neuroblastoma, as well as the possible therapeutic implications of valeriana-type iridoid glycosides in anti-cancer treatment.

Young and undamaged recombinant albumin alleviates T2DM by improving hepatic glycolysis through EGFR and protecting islet β cells in mice

BACKGROUND

Albumin is the most abundant protein in serum and serves as a transporter of free fatty acids (FFA) in blood vessels. In type 2 diabetes mellitus (T2DM) patients, the reduced serum albumin level is a risk factor for T2DM development and progression, although this conclusion is controversial. Moreover, there is no study on the effects and mechanisms of albumin administration to relieve T2DM. We examined whether the administration of young and undamaged recombinant albumin can alleviate T2DM in mice.

METHODS

The serum albumin levels and metabolic phenotypes including fasting blood glucose, glucose tolerance tests, and glucose-stimulated insulin secretion were studied in db/db mice or diet-induced obesity mice treated with saline or young, undamaged, and ultrapure rMSA. Apoptosis assays were performed at tissue and cell levels to determine the function of rMSA on islet β cell protection. Metabolic flux and glucose uptake assays were employed to investigate metabolic changes in saline-treated or rMSA-treated mouse hepatocytes and compared their sensitivity to insulin treatments.

RESULTS

In this study, treatment of T2DM mice with young, undamaged, and ultrapure recombinant mouse serum albumin (rMSA) increased their serum albumin levels, which resulted in a reversal of the disease including reduced fasting blood glucose levels, improved glucose tolerance, increased glucose-stimulated insulin secretion, and alleviated islet atrophy. At the cellular level, rMSA improved glucose uptake and glycolysis in hepatocytes. Mechanistically, rMSA reduced the binding between CAV1 and EGFR to increase EGFR activation leading to PI3K-AKT activation. Furthermore, rMSA extracellularly reduced the rate of fatty acid uptake by islet β-cells, which relieved the accumulation of intracellular ceramide, endoplasmic reticulum stress, and apoptosis. This study provided the first clear demonstration that injections of rMSA can alleviate T2DM in mice.

CONCLUSION

Our study demonstrates that increasing serum albumin levels can promote glucose homeostasis and protect islet β cells, which alleviates T2DM.

Association between serum albumin and 60-day mortality in Chinese Hakka patients with non-APL acute myeloid leukemia: a retrospective cohort study

BACKGROUND

Acute myeloid leukemia (AML) is the main type of adult leukemia, and 60-day mortality is a vital clinical problem that doctors have to face at the begin with treatment. Studies on the association between serum albumin and 60-day mortality from AML (non-APL) are limited.

METHODS

In this retrospective cohort study, ALB was measured after admission in all patients diagnosed with primary AML from Affiliated Ganzhou Hospital of Nanchang University between January 2013 and May 2021. The outcome was all-cause, 60-day mortality. Multivariable Cox regression analyses were performed to calculate the adjusted hazard ratio (HR) and its corresponding 95% confidence interval (CI).

RESULTS

This study included 394 primary AML patients. The overall 60-day mortality was 28.9% (114/394); it was 43.1% (56/130), 27.5% (36/131), and 16.5% (22/133) for ALB quantile1 (Q, < 34.5 g/L), quantile 2 (Q2, 34.5-38.5 g/L), and quantile 3 (Q3, ≥ 38.6 g/L), respectively (P = 0.001). After adjusting for potential confounders, we found an association between a 6% decrease in 60-day mortality rate and a 1 g/L increase in ALB level (HR = 0.94, 95% CI: 0.89-0.99, P = 0.015), which was associated with 38 and 70% decreases in 60-day mortality rates in Q2 (HR = 0.50, 95% CI: 0.30-0.86, P = 0.012) and Q3 (HR = 0.47, 95% CI: 0.2 5-0.90, P = 0.022), respectively, compared with that in Q1. Similar results were obtained after subgrouping based on an ALB level of 35 g/L (HR = 0.55, 95% CI: 0.34-0.88, P = 0.013).

CONCLUSIONS

Serum albumin was significantly associated with 60-day mortality of primary AML, which has important clinical significance. Further investigation is warranted.

Albumin Stimulates Epithelial Na+ Transport and Barrier Integrity by Activating the PI3K/AKT/SGK1 Pathway

Albumin is a major serum protein and is frequently used as a cell culture supplement. It is crucially involved in the regulation of osmotic pressure and distribution of fluid between different compartments. Alveolar epithelial Na⁺ transport drives alveolar fluid clearance (AFC), enabling air breathing. Whether or not albumin affects AFC and Na⁺ transport is yet unknown. We therefore determined the acute and chronic effects of albumin on Na⁺ transport in fetal distal lung epithelial (FDLE) cells and the involved kinase pathways. Chronic BSA treatment strongly increased epithelial Na⁺ transport and barrier integrity in Ussing chambers. BSA did not elevate mRNA expression of Na⁺ transporters in FDLE cells after 24 h. Moreover, acute BSA treatment for 45 min mimicked the chronic effects. The elevated Na⁺ transport was caused by an increased maximal ENaC activity, while Na,K-ATPase activity remained unchanged. Acute and chronic BSA treatment lowered membrane permeability, confirming the increased barrier integrity observed in Ussing chambers. Western blots demonstrated an increased phosphorylation of AKT and SGK1, and PI3K inhibition abolished the stimulating effect of BSA. BSA therefore enhanced epithelial Na⁺ transport and barrier integrity by activating the PI3K/AKT/SGK1 pathway.

Albumin and C-reactive protein relate to functional and body composition parameters in patients admitted to geriatric rehabilitation after acute hospitalization: findings from the RESORT cohort

PURPOSE

Albumin and C-reactive protein (CRP) are non-specific markers of inflammation, which could affect muscle tissue during acute hospitalization. We investigated the association between albumin and CRP during acute hospitalization with functional and body composition parameters in patients admitted to geriatric rehabilitation.

METHODS

The REStORing Health of Acutely Unwell AdulTs (RESORT) cohort includes geriatric rehabilitation patients assessed for change in activities of daily living (ADL, using the Katz index) during acute hospitalization, and subsequently for Katz ADL, gait speed (GS), handgrip strength (HGS) and skeletal muscle mass index (SMI) at geriatric rehabilitation admission. Albumin and CRP average (median), variation (interquartile range), and maximum or minimum were collected from serum samples, and were examined for their association with functional and body composition parameters using multivariable linear regression analysis adjusted for age, sex and length of acute hospital stay.

RESULTS

1769 Inpatients were included for analyses (mean age 82.6 years ± 8.1, 56% female). Median length of acute hospitalization was 7 [IQR 4, 13] days and median number of albumin and CRP measurements was 5 [IQR 3, 12] times. ADL declined in 89% of patients (median - 3 points, IQR - 4, - 2). Lower average albumin, higher albumin variation and lower minimum albumin were associated with larger declines in ADL and with lower ADL, GS, HGS and SMI at geriatric rehabilitation admission. Higher average and maximum CRP were associated with lower GS.

CONCLUSION

Inflammation, especially lower albumin concentrations, during acute hospitalization is associated with lower physical function at geriatric rehabilitation admission.

Albumin protects the liver from tumor necrosis factor α-induced immunopathology

Besides its oncotic power, albumin exerts pleiotropic actions, including binding, transport, and detoxification of endogenous and exogenous molecules, antioxidant activity, and modulation of immune and inflammatory responses. In particular, recent studies have demonstrated that albumin reduces leukocyte cytokine production. Here, we investigated whether albumin also has the ability to protect tissues from the damaging actions of these inflammatory mediators. We circumscribed our investigation to tumor necrosis factor (TNF) α, which exemplifies the connection between immunity and tissue injury. In vivo experiments in analbuminemic mice showed that these mice exhibit a more pronounced response to a model of TNFα-mediated liver injury induced by the administration of lipopolysaccharide (LPS) and D-galactosamine (D-gal). A tissue protective action against LPS/D-gal liver injury was also observed during the administration of human albumin to humanized mice expressing the human genes for albumin and neonatal Fc receptor (hAlb^+/+ /hFcRn^+/+ ) with preestablished carbon tetrachloride (CCl₄ )-induced early cirrhosis. The cytoprotective actions of albumin against TNFα-induced injury were confirmed ex vivo, in precision-cut liver slices, and in vitro, in primary hepatocytes in culture. Albumin protective actions were independent of its scavenging properties and were reproduced by recombinant human albumin expressed in Oryza sativa. Albumin cytoprotection against TNFα injury was related to inhibition of lysosomal cathepsin B leakage accompanied by reductions in mitochondrial cytochrome c release and caspase-3 activity. These data provide evidence that in addition to reducing cytokines, the albumin molecule also has the ability to protect tissues against inflammatory injury.

Serum HSP90-Alpha and Oral Squamous Cell Carcinoma : A Prospective Biomarker

AIM

Current study aims to perform differential protein expression analysis of serum samples from Oral squamous cell carcinoma (OSCC) patients and healthy controls in search of potential diagnostic and/or prognostic biomarker(s).

OBJECTIVE

OSCC is diagnosed late, resulting in poor survival and high mortality. Identification of non-invasive prognostic biomarker is of utmost importance for early diagnosis and proper management of the disease; hence we used proteomic approach to identify potential biomarkers from serum.

METHODS

Serum samples (OSCC n=45 and control n=30) were depleted and proteins were separated using 2-D gel electrophoresis followed by identification by mass spectrometric analysis. Gene expression analysis of identified proteins in malignant and normal tissue was also performed to complement proteomics studies.

RESULTS

Among differentially expressed proteins, a noteworthy observation was up regulation of Heat shock protein alpha (HSP90α) from serum of oral cancer patients. We also observed elevated levels of Haptoglobin (HP) along with down regulation of Type II keratin cytoskeletal 1(KRT1) and serum Albumin (ALB) in oral cancer patients. Gene expression studies of identified proteins in malignant and normal tissue revealed a similar pattern with the exception of KRT1. We believe that elevated levels of serum HSP90 alpha might be used as a potential biomarker.

CONCLUSION

Our findings suggest the contribution of HSP90 alpha and other identified proteins in oral pathology as pro/anti apoptotic modulators, thus they are being considered as predictive biomarkers.

The Comparison of Sarcopenia Diagnostic Criteria using AWGS 2019 with the Other Five Criteria in West China

INTRODUCTION

The aim of this study was to investigate the prevalence and associated factors of sarcopenia defined by different criteria in community-dwelling adults of west China using the baseline data of West-China Health and Aging Trend (WCHAT) study.

METHODS

Adults aged 50 years or older in communities of Yunnan, Guizhou, Sichuan, and Xinjiang provinces were enrolled in this study. We applied 6 -diagnostic criteria (AWGS 2019, AWGS 2014, EWGSOP1, -EWGSOP2, IWGS, and FNIH) to define sarcopenia. Muscle mass was measured based on bioimpedance analysis. Handgrip strength and walking speed were recorded, respectively. Different variables like anthropometry measures, lifestyles, chronic disease, and blood test were collected.

RESULTS

We included 4,500 participants. The prevalence of sarcopenia was 22.8, 19.3, 57.1, 11.8, 24.1, and 18.1% according to the AWGS 2019, AWGS 2014, EWGSOP 1, EWGSOP 2, IWGS, and FNIH criteria, respectively. We found that serum albumin level was independently associated with sarcopenia using AWGS 2019 and IWGS. And vitamin D level was independently associated with sarcopenia using AWGS 2014, -EWGSOP2, and FNIH. While age, depressive status, BMI, hemoglobin, vitamin D, and insulin level were all significantly associated with sarcopenia using AWGS 2014, but all of these factors were not significant using AWGS 2019.

CONCLUSIONS

Sarcopenia was highly prevalent in west China regardless of the diagnostic criteria. Serum albumin and vitamin D level were mostly associated with sarcopenia defined by different criteria. While most risk factors associated with the AWGS 2014-defined sarcopenia exhibited no consistent pattern with AWGS 2019, the validity of the AWGS 2019 consensus needs to be confirmed in further prospective studies.

Sarcopenia, Obesity and Sarcopenia Obesity in Comparison: Prevalence, Metabolic Profile, and Key Differences: Results from WCHAT Study

OBJECTIVE

To identify the prevalence, lifestyle factors, chronic disease status, and assessing the metabolic profile, comparing key differences in a cohort of subjects with non-sarcopenia/non-obesity (H), sarcopenia/non-obesity (S), non-sarcopenia/obesity (O) and sarcopenia obesity (SO) in a multi-ethnic population in west China.

DESIGN

A cross-sectional study.

SETTING

The communities in Yunnan, Guizhou, Sichuan, and Xinjiang provinces.

PARTICIPANTS

We included 4,500 participants aged 50 years or older who did bioelectrical impedance in our analysis from West China Health and Aging Trend (WCHAT) study.

MEASUREMENTS

We measured gait speed, handgrip strength and muscle mass by using bioelectrical impedance analysis (BIA) for all participants. We defined sarcopenia using the diagnostic algorithm recommended by the Asian Working Group for Sarcopenia (AWGS). Obesity was defined as the highest sex-specific quintile of the percentage body fat. Different variables like anthropometry measures, life styles, chronic disease and blood test were collected. Analysis of variance and a multinomial logistic regression analysis adjusting for covariates were used to assess the differences of metabolic profiles among different groups.

RESULTS

Of 4500 participants aged 50 years old or older, the proportions of H, O, S, SO were 63.0%, 17.7%, 16.7% and 2.6%, respectively. And the prevalence of S subjects in men was 18.3% and 15.7% in women, while the prevalence of SO was 3.7% in men and 2.0% in women. Data showed that the prevalence of S and SO has an aging increase pattern which was opposite with O. Both S and SO tends to be older, lower educational level, without spouse, smoking, comorbidity of chronic disease, poor nutrition status, depression and cognitive decline compared to H and S seems to be worse than SO. Compared to H, S cohort showed a decrease in Vitamin D, triglyceride, albumin, fasting glucose, insulin, creatinine, ALT, nutrition scores and increase in HDL. SO cohort were observed for an increase in cholesterol, LDL, total protein and decrease in vitamin D. While O cohort showed an increase in triglyceride, cholesterol, LDL, total protein, glucose, insulin, WBC, uric acid, ALT and nutrition scores, but a decrease in HDL and vitamin D level.

CONCLUSIONS

Among individuals aged 50 years old or older in West China. S, O and SO participants demonstrate distinct differences in the life-styles, chronic disease profile, and metabolic profiles. The prevalence of S and SO has an aging increase pattern contrary to O. Both S and SO tend to be older, lower educational level, without spouse, smoking, comorbidity of chronic disease, poor nutrition status, depression and cognitive decline compared to H and S looks like to be worse than SO. Besides, the S subjects seem to have more metabolic index changes than SO compared to H. While O subjects have some contrary metabolic index to S subjects.

Immunoproteomic identification and characterization of Ni2+-regulated proteins implicates Ni2+ in the induction of monocyte cell death

Nickel allergy is the most common cause of allergic reactions worldwide, with cutaneous and systemic effects potentially affecting multiple organs. Monocytes are precursors of not only macrophages but also dendritic cells, the most potent activators of nickel hypersensitivity. Monocytes are themselves important antigen-presenting cells, capable of nickel-specific T-cell activation in vivo and in vitro, in addition to being important for immediate innate immune inflammation. To elucidate early Ni²⁺-dependent inflammatory molecular mechanisms in human monocytes, a Ni²⁺-specific proteomic approach was applied. Quantitative two-dimensional (2D) differential gel electrophoresis and Delta2D software analyses coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) revealed that Ni²⁺ significantly regulated 56 protein species, of which 36 were analyzed by MALDI-MS. Bioinformatics analyses of all identified proteins resulted in Ni²⁺-associated functional annotation clusters, such as cell death, metal ion binding, and cytoskeletal remodeling. The involvement of Ni²⁺ in the induction of monocyte cell death, but not T-cell death, was observed at Ni²⁺ concentrations at or above 250 μM. Examination of caspase activity during Ni²⁺-mediated cell death revealed monocytic cell death independent of caspase-3 and -7 activity. However, confocal microscopy analysis demonstrated Ni²⁺-triggered cytoskeletal remodeling and nuclear condensation, characteristic of cellular apoptosis. Thus, Ni²⁺-specific peripheral blood mononuclear cell stimulation suggests monocytic cell death at Ni²⁺ concentrations at or above 250 μM, and monocytic effects on immune regulation at lower Ni²⁺ concentrations.

Serum albumin and muscle measures in a cohort of healthy young and old participants

Consensus on clinically valid diagnostic criteria for sarcopenia requires a systematical assessment of the association of its candidate measures of muscle mass, muscle strength, and physical performance on one side and muscle-related clinical parameters on the other side. In this study, we systematically assessed associations between serum albumin as a muscle-related parameter and muscle measures in 172 healthy young (aged 18-30 years) and 271 old participants (aged 69-81 year) from the European MYOAGE study. Muscle measures included relative muscle mass, i.e., total- and appendicular lean mass (ALM) percentage, absolute muscle mass, i.e., ALM/height(2) and total lean mass in kilograms, handgrip strength, and walking speed. Muscle measures were standardized and analyzed in multivariate linear regression models, stratified by age. Adjustment models included age, body composition, C-reactive protein and lifestyle factors. In young participants, serum albumin was positively associated with lean mass percentage (p = 0.007) and with ALM percentage (p = 0.001). In old participants, serum albumin was not associated with any of the muscle measures. In conclusion, the association between serum albumin and muscle measures was only found in healthy young participants and the strongest for measures of relative muscle mass.

NOX1 supports the metabolic remodeling of HepG2 cells

NADPH oxidases are important sources of reactive oxygen species (ROS) which act as signaling molecules in the regulation of protein expression, cell proliferation, differentiation, migration and cell death. The NOX1 subunit is over-expressed in several cancers and NOX1 derived ROS have been repeatedly linked with tumorigenesis and tumor progression although underlying pathways are ill defined. We engineered NOX1-depleted HepG2 hepatoblastoma cells and employed differential display 2DE experiments in order to investigate changes in NOX1-dependent protein expression profiles. A total of 17 protein functions were identified to be dysregulated in NOX1-depleted cells. The proteomic results support a connection between NOX1 and the Warburg effect and a role for NOX in the regulation of glucose and glutamine metabolism as well as of lipid, protein and nucleotide synthesis in hepatic tumor cells. Metabolic remodeling is a common feature of tumor cells and understanding the underlying mechanisms is essential for the development of new cancer treatments. Our results reveal a manifold involvement of NOX1 in the metabolic remodeling of hepatoblastoma cells towards a sustained production of building blocks required to maintain a high proliferative rate, thus rendering NOX1 a potential target for cancer therapy.

Beta-lactam antibiotics modulate T-cell functions and gene expression via covalent binding to cellular albumin

Recent work has suggested that beta-lactam antibiotics might directly affect eukaryotic cellular functions. Here, we studied the effects of commonly used beta-lactam antibiotics on rodent and human T cells in vitro and in vivo on T-cell-mediated experimental autoimmune diseases. We now report that experimental autoimmune encephalomyelitis and adjuvant arthritis were significantly more severe in rats treated with cefuroxime and other beta-lactams. T cells appeared to mediate the effect: an anti-myelin basic protein T-cell line treated with cefuroxime or penicillin was more encephalitogenic in adoptive transfer experiments. The beta-lactam ampicillin, in contrast to cefuroxime and penicillin, did not enhance encephalomyelitis, but did inhibit the autoimmune diabetes developing spontaneously in nonobese diabetic mice. Gene expression analysis of human peripheral blood T cells showed that numerous genes associated with T helper 2 (Th2) and T regulatory (Treg) differentiation were down-regulated in T cells stimulated in the presence of cefuroxime; these genes were up-regulated in the presence of ampicillin. The T-cell protein that covalently bound beta-lactam antibiotics was found to be albumin. Human and rodent T cells expressed albumin mRNA and protein, and penicillin-modified albumin was taken up by rat T cells, leading to enhanced encephalitogenicity. Thus, beta-lactam antibiotics in wide clinical use have marked effects on T-cell behavior; beta-lactam antibiotics can function as immunomodulators, apparently through covalent binding to albumin.

Resuscitation fluids and endotoxin-induced myocardial dysfunction: is selection a load-independent differential issue?

Along with redistributive shock, myocardial dysfunction is now recognized as highly prevalent in early severe sepsis. Indeed, aside from their distinct loading potency, resuscitation fluids have been poorly investigated as to their specific molecular impact on myocardial dysfunction. The objective of this study was to evaluate the load-independent biological impact of different resuscitation fluids on endotoxin-induced myocardial dysfunction. Adult rats implanted with a central venous catheter were given an intraperitoneal injection of endotoxin (lipopolysaccharides [LPSs], Escherichia coli, 10 mg/kg) or normal saline (sham) and subsequently infused or not with similar "fluid potency" loading resuscitation fluid (normal saline, albumin [Alb], or hypertonic saline solution) for 6 to 24 h, followed by echocardiographic and hemodynamic monitoring together with biochemical and histopathologic evaluation. Intervention was to assess the selective influence of load-independent fluid infusion on the aforementioned parameters in groups of animals challenged or not with LPS. At comparative plasma volumes, Alb improved myocardial homeostasis after LPS challenge by (i) reducing left ventricular relative wall diastolic thickness, interstitial space enlargement, and endogenous Alb content; (ii) limiting cardiac apoptosis and sustaining extracellular signal-regulated mitogen-activated protein kinase activation; and (iii) enhancing the expression pattern of heme-oxygenase 1/inducible nitric oxide synthase. Hypertonic saline solution was also cardioprotective by early prevention of myocardial dysfunction and by reducing cardiac apoptosis. Fluid infusions have distinct load-independent structural/biological impacts on endotoxin-induced myocardial dysfunction. Albumin and hypertonic saline solution are the most pleiotropic fluids in protecting the heart after a "sepsis" hit.

The phosphoinositide 3-kinase signaling pathway in normal and malignant B cells: activation mechanisms, regulation and impact on cellular functions

The phosphoinositide 3-kinase (PI3K) pathway is a central signal transduction axis controlling normal B cell homeostasis and activation in humoral immunity. The p110δ PI3K catalytic subunit has emerged as a critical mediator of multiple B cell functions. The activity of this pathway is regulated at multiple levels, with inositol phosphatases PTEN and SHIP both playing critical roles. When deregulated, the PI3K pathway can contribute to B cell malignancies and autoantibody production. This review summarizes current knowledge on key mechanisms that activate and regulate the PI3K pathway and influence normal B cell functional responses including the development of B cell subsets, antigen presentation, immunoglobulin isotype switch, germinal center responses, and maintenance of B cell anergy. We also discuss PI3K pathway alterations reported in select B cell malignancies and highlight studies indicating the functional significance of this pathway in malignant B cell survival and growth within tissue microenvironments. Finally, we comment on early clinical trial results, which support PI3K inhibition as a promising treatment of chronic lymphocytic leukemia.

The JAK3-selective inhibitor PF-956980 reverses the resistance to cytotoxic agents induced by interleukin-4 treatment of chronic lymphocytic leukemia cells: potential for reversal of cytoprotection by the microenvironment

Extensive evidence suggests that the malignant cells of chronic lymphocytic leukemia (CLL) patients are in close contact with activated T lymphocytes, which secrete a range of cytoprotective cytokines including interleukin-4 (IL-4). IL-4 induced the rapid phosphorylation and activation of the signal transducer and activator of transcription 6 transcription factor in CLL cells in vitro. Longer incubation with IL-4 resulted in up-regulation of the antiapoptotic proteins, Mcl-1 and Bcl-XL. All of these events were blocked by the JAK3-selective inhibitor, PF-956980. A dye reduction cytotoxicity assay showed that IL-4 induced resistance to the cytotoxic drugs fludarabine and chlorambucil and to the novel p53-elevating agent nutlin 3. IL-4–induced drug resistance was reversed by PF-956980. These conclusions were confirmed by independent assays for apoptosis induction (annexin V binding, cleavage of poly[ADP-ribose] polymerase, and morphologic analysis). Coculture with bone marrow stromal cells in the presence of supernatants derived from activated T-lymphocyte cultures also protected CLL cells from apoptosis induction by chlorambucil. Protection by these combined signals was reversed by PF-956980. The data here provide a preclinical rationale for the possible therapeutic use of PF-956980 in conjunction with conventional cytotoxic drugs to achieve more extensive killing of CLL cells by overcoming antiapoptotic signaling by the microenvironment.

APRIL promotes cell-cycle progression in primary multiple myeloma cells: influence of D-type cyclin group and translocation status

A proliferation-inducing ligand (APRIL) promotes survival and drug resistance in multiple myeloma (MM) cell lines. We studied the effect of APRIL on cell-cycle behavior in primary MM cells and correlated our findings with D-type cyclin expression by immunohistochemistry and/or Western blotting. In MM cases, expressing cyclin D2 APRIL significantly increased the percentage of CD138(+) cells in S + G(2)/M phase (from 8.4% ± 1.9% to 14.3% ± 2.6%, n = 15, P < .01), whereas a lesser effect was seen in cases expressing cyclin D1 (n = 18). Cell-cycle response to APRIL was most marked for cyclin D2-expressing cases with IgH translocations (P < .01) and was accompanied by increased expression of cyclin D2, CDK4, CDK6, and phospho-retinoblastoma protein. Cell-cycle proteins in cyclin D1(+) cells were not modulated by APRIL. Surface expression of B-cell maturation antigen and transmembrane activator and calcium-modulating cyclophilin ligand interactor was not significantly different between cyclin D1(+) and D2(+) MM cells. We observed activation of nuclear factor-κB and PI3-kinase pathways in response to APRIL in both cyclin D1(+) and D2(+) MM cells. In conclusion, APRIL stimulates G(1)/S progression in cyclin D2(+) MM cells bearing IgH translocations but has minimal effect on cyclin D1(+) cells, suggesting MM cells from different cyclin D/translocation classes rely on different mechanisms for cell-cycle re-entry.

Antiapoptotic effect of interleukin-2 (IL-2) in B-CLL cells with low and high affinity IL-2 receptors

Although B chronic lymphocytic leukemia (B-CLL) cells express the alpha chain of the interleukin-2 (IL-2) receptor CD25, little is known about the effect of IL-2 on apoptosis in B-CLL cells. We have shown previously that stimulation of B-CLL cells with a CpG-oligonucleotide induces IL-2 high affinity receptors. In our current work, we analyzed the effect of IL-2 on apoptosis in resting B-CLL cells and in our model of activated B-CLL cells (CD25 high cells). IL-2 had modest antiapoptotic activity in resting B-CLL cells. In contrast, IL-2 was much more potent to prevent apoptosis in activated cells. Prevention of cell death was also associated with the maintenance of the mitochondrial membrane potential. While only limited regulation of apoptosis controlling proteins was observed in resting B-CLL cells, IL-2 had strong effects on MCL-1, Bcl-xl, and survivin expression and inhibited Bax cleavage in CD25 high cells. Interestingly, expression of Bcl-2 was reduced. Addition of IL-2 to activated B-CLL cells caused rapid phosphorylation of Akt, while IL-2 failed to significantly phosphorylate Akt in resting B-CLL cells. Pharmacological inhibition of Akt by LY294002 restored sensitivity of activated B-CLL cells to fludarabine. IL-2 might be an important survival factor in activated B-CLL cells and might contribute to disease progression by upregulation of several critical antiapoptotic proteins.

Lysophosphatidic acid receptor expression in chronic lymphocytic leukemia leads to cell survival mediated though vascular endothelial growth factor expression

Lysophosphatidic acid (LPA) protects chronic lymphocytic leukemia (CLL) cells from apoptosis. Vascular endothelial growth factor (VEGF) also protects CLL cells against apoptosis. The mechanism for LPA protection against apoptosis in CLL cells is unknown. Herein, we show CLL cells express LPA receptors LPA(1-5) but in normal B cells, LPA(1) was rarely expressed and LPA(3,) LPA(4,) and LPA(6) were undetectable whereas the other LPA receptors were expressed. LPA plasma levels are similar in patients with CLL compared to healthy controls. In contrast, plasma levels of VEGF are elevated in patients with CLL compared to healthy controls and LPA treatment induced VEGF secretion in CLL cells. CLL cells also express VEGF receptors and LPA protection against Flu induced apoptosis is blocked by inhibition of VEGF receptor activation. These results indicate that LPA protects CLL cells from apoptosis through higher expression of LPA receptors and autocrine production of VEGF.

CD160 signaling mediates PI3K-dependent survival and growth signals in chronic lymphocytic leukemia

B-cell chronic lymphocytic leukemia (CLL) expresses CD160, a glycosylphosphatidylinositol-linked receptor found on normal natural killer (NK) and T cells, but not B cells. CD160 is a multifunctional molecule in normal lymphocytes, but its role in CLL biology is unknown. In vitro, CLL cells undergo rapid spontaneous apoptosis, which CD160 activation protected against-mean cell viability increased from 67% to 79% (P < .001). This was associated with up-regulation of Bcl-2, Bcl-xL, and Mcl-1, but not Bax. As expected from these changes in Bcl-2/Bax and Bcl-xL/Bax ratios, CD160 triggering reduced mitochondrial membrane potential collapse and cytochrome c release. CD160 stimulation also induced DNA synthesis, cell cycle progression, and proliferation. B-cell antigen receptor (BCR)-induced CLL proliferation was generally greater than with CD160, but marked variation was seen. Both BCR and CD160 signaling led to CLL secretion of interleukin-6 (IL-6) and IL-8, although CD160 induced greater increases of IL-6 (51-fold) and IL-8 (15-fold). Survival and activation signals mediated by CD160 showed dose-dependent suppression by phosphoinositide-3 kinase (PI3K) inhibitors. Thus, in vitro, CLL cells can use the CD160 pathway for survival and activation, mimicking CD160 signaling in normal NK and CD8(+) T cells. Establishing the pathophysiologic relevance of these findings may reveal new therapeutic targets.

Role of decreased production of interleukin-10 and interferon-gamma in spontaneous apoptosis of B-chronic lymphocytic leukemia lymphocytes in vitro

BACKGROUND AND AIMS

B-chronic lymphocytic leukemia (B-CLL) is characterized by the progressive accumulation of small B lymphocytes that do not undergo apoptosis due to an underlying defect. One potential mechanism of defective apoptosis may be irregular cytokine production. The goal of our investigation was to determine in vitro production of relevant cytokines by lymphocytes of B-CLL patients.

METHODS

Thirty untreated (stage A) B-CLL patients, as well as 20 stage B and C patients and 30 healthy volunteers as a control group were examined. Interleukin-4 (IL-4), interferon-gamma (IFN-gamma), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-alpha) were measured by enzyme-linked immunosorbent assay (ELISA) in supernatants of lymphocyte cultures of all three investigated groups. The method applied for detecting apoptosis was fluorescence microscopic analysis using acridine orange/ethidium bromide (AO/EB) double staining.

RESULTS

Investigation showed that in vitro lymphocyte production of IL-10 and IFN-gamma were significantly decreased in B-CLL patients, whereas there were no statistically significantly differences of IL-4 and TNF-alpha production among the tested groups. Compared with the spontaneous apoptosis observed in control subjects' lymphocytes, B-CLL lymphocytes showed increased percentages of apoptotic cells after incubation for 24h. Interestingly, increased spontaneous apoptosis of B-CLL lymphocytes was followed by decreased IL-10 and IFN-gamma production. Stage of disease did not influence B-CLL lymphocyte spontaneous apoptosis in vitro.

CONCLUSIONS

These changes in cytokine production in cultures of B-CLL lymphocytes may be one of the potential mechanisms in the pathogenesis of abnormal apoptosis.

Akt inhibitors induce apoptosis in chronic lymphocytic leukemia cells

BACKGROUND

The phosphatidylinositol-3-kinase/Akt pathway has been described to be critical in the survival of chronic lymphocytic leukemia cells. In this study we analyzed the effect of two selective chemical inhibitors of Akt (Akti-1/2 and A-443654) on the survival of chronic lymphocytic leukemia cells.

DESIGN AND METHODS

Using cytometry we studied the cytotoxic effects of Akt inhibitors on peripheral B and T lymphocytes from patients with chronic lymphocytic leukemia and from healthy donors. We studied the changes induced by Akti-1/2 and A-443654 at the mRNA level by performing reverse transcriptase multiplex ligation-dependent probe amplification. We also studied the changes induced by both Akt inhibitors in some BCL-2 protein family members on chronic lymphocytic leukemia cells by western blotting. Moreover, we analyzed the cytotoxic effect of Akt inhibitors in patients' cells with deleted/mutated TP53.

RESULTS

Both inhibitors induced apoptosis in chronic lymphocytic leukemia cells in a dose-dependent manner. Moreover, B cells from patients with chronic lymphocytic leukemia were more sensitive to Akt inhibitors than T cells from leukemic patients, and B or T cells from healthy donors. Survival factors for chronic lymphocytic leukemia cells, such as interleukin-4 and stromal cell-derived factor-1alpha, were not able to block the apoptosis induced by either Akt inhibitor. Akti-1/2 did not induce any change in the mRNA expression profile of genes involved in apoptosis, while A-443654 induced some changes, including an increase in NOXA and PUMA mRNA levels, suggesting the existence of additional targets for A-443654. Both inhibitors induced an increase in PUMA and NOXA protein levels, and a decrease in MCL-1 protein level. Moreover, Akti-1/2 and A-443654 induced apoptosis irrespective of TP53 status.

CONCLUSIONS

These results demonstrate that Akt inhibitors induce apoptosis of chronic lymphocytic leukemia cells and might be a new therapeutic option for the treatment of chronic lymphocytic leukemia.

2-Phenylacetylenesulfonamide (PAS) induces p53-independent apoptotic killing of B-chronic lymphocytic leukemia (CLL) cells

We studied the actions of 2-phenylacetylenesulfonamide (PAS) on B-chronic lymphocytic leukemia (CLL) cells. PAS (5-20 microM) initiated apoptosis within 24 hours, with maximal death at 48 hours asassessed by morphology, cleavage of poly(ADP-ribose) polymerase (PARP), caspase 3 activation, and annexin V staining. PAS treatment induced Bax proapoptotic conformational change, Bax movement from the cytosol to the mitochondria, and cytochrome c release, indicating that PAS induced apoptosis via the mitochondrial pathway. PAS induced approximately 3-fold up-regulation of proapoptotic Noxa protein and mRNA levels. In addition, Noxa was found unexpectedly to be bound to Bcl-2 in PAS-treated cells. PAS treatment of CLL cells failed to up-regulate p53, suggesting that PAS induced apoptosis independently of p53. Furthermore, PAS induced apoptosis in CLL isolates with p53 gene deletion in more than 97% of cells. Normal B lymphocytes were as sensitive to PAS-induced Noxa up-regulation and apoptosis as were CLL cells. However, both T lymphocytes and bone marrow hematopoietic progenitor cells were relatively resistant to PAS. Our data suggest that PAS may represent a novel class of drug that induces apoptosis in CLL cells independently of p53 status by a mechanism involving Noxa up-regulation.

Serum albumin protects from cytokine-induced pancreatic beta cell death by a phosphoinositide 3-kinase-dependent mechanism

The present study was undertaken to investigate the biological activity of serum albumin when pancreatic beta cells were challenged by cytokines and pro-apoptotic reactive oxygen species like H(2)O(2). Culture of mouse islets or INS-1E beta cells for 24 h in the presence of H(2)O(2) (25 micromol/l) increased cell death. This demise was prevented by serum albumin, dependent on its free sulfhydryl group, emphasizing that albumin may scavenge H(2)O(2) due to its antioxidant properties. Culture for 48 h with a cytokine mixture of IL-1beta (160 pg/ml), IFN-gamma (200 ng/ml), and TNF-alpha (2 ng/ml) revealed that albumin, also protected against cytokine-induced death of both mouse islets and INS-1E beta cells. This protective effect against cytokine-induced beta cell death was, however, not dependent on albumins free sulfhydryl group, but was inhibited by the phosphoinositide 3-kinase (PI3K) inhibitors LY294002 (25 micromol/l) and wortmannin (1 micromol/l), suggesting that albumin may rescue beta cells from cytokine-induced cell death by activation of PI3K. In accordance, albumin stimulated phosphorylation of Akt, a down-stream target for PI3K. In conclusion, it is suggested that albumin may be a survival factor for pancreatic beta cells through scavenging of reactive oxygen species and by PI3K-dependent activation of Akt.

Autologous serum eye drops for the treatment of dry eye diseases

Conventional treatment of dry eye mainly consists of the use of preservative-free artificial eye drops and punctal occlusion. None of the commercially available artificial tear preparations include essential tear components such as epidermal growth factor, hepatocyte growth factor, fibronectin, neurotrophic growth factor, and vitamin A-all of which have been shown to play important roles in the maintenance of a healthy ocular surface epithelial milieu. We reported previously that autologous serum (AS) eye drops contain these essential factors and that AS eye drops are beneficial in the treatment of ocular surface diseases such as persistent epithelial defects, superior limbic keratoconjunctivitis, keratoconjunctivitis sicca, and neurotrophic keratopathy. However, there is some controversy regarding the efficacy of AS treatment. We demonstrated that this modality is more effective than artificial tears in a randomized control study. In in vivo and in vitro experiments, AS eye drops showed marked suppression of apoptosis in the conjunctival and corneal epithelium. Albumin, the major protein in serum, improved ocular surface damage in vivo and rescued apoptosis after serum deprivation in vitro. The biological background of AS eye drops and previous clinical studies of these medications for the treatment of dry eye are discussed.

p53-mediated apoptosis of CLL cells: evidence for a transcription-independent mechanism

The p53 protein plays a key role in securing the apoptotic response of chronic lymphocytic leukemia (CLL) cells to genotoxic agents. Transcriptional induction of proapoptotic proteins including Puma are thought to mediate p53-dependent apoptosis. In contrast, recent studies have identified a novel nontranscriptional mechanism, involving direct binding of p53 to antiapoptotic proteins including Bcl-2 at the mitochondrial surface. Here we show that the major fraction of p53 induced in CLL cells by chlorambucil, fludarabine, or nutlin 3a was stably associated with mitochondria, where it binds to Bcl-2. The Puma protein, which was constitutively expressed in a p53-independent manner, was modestly up-regulated following p53 induction. Pifithrin α, an inhibitor of p53-mediated transcription, blocked the up-regulation of Puma and also of p21CIP1. Surprisingly, pifithrin α dramatically augmented apoptosis induction by p53-elevating agents and also accelerated the proapoptotic conformation change of the Bax protein. These data suggest that direct interaction of p53 with mitochondrial antiapoptotic proteins including Bcl-2 is the major route for apoptosis induction in CLL cells and that p53's transcriptional targets include proteins that impede this nontranscriptional pathway. Therefore, strategies that block up-regulation of p53-mediated transcription may be of value in enhancing apoptosis induction of CLL cells by p53-elevating drugs.

Why is CLL refractory to bortezomib?

In this issue of Blood, Liu and colleagues present evidence that flavonoids present in plasma may compromise the ability of the proteasome inhibitor bortezomib to induce apoptosis of CLL cells.

EHDS are serine phosphoproteins: EHD1 phosphorylation is enhanced by serum stimulation

Endocytic processes are mediated by multiple protein-protein interacting modules and regulated by phosphorylation and dephosphorylation. The Eps15 homology domain containing protein 1 (EHD1) has been implicated in regulating recycling of proteins, internalized both in clathrin-dependent and clathrin-independent endocytic pathways, from the recycling compartment to the plasma membrane. EHD1 was found in a complex with clathrin, adaptor protein complex-2 (AP-2) and insulin-like growth factor-1 receptor (IGF-1R), and was shown to interact with Rabenosyn-5, SNAP29, EHBP1 (EH domain binding protein 1) and syndapin I and II. In this study, we show that EHD1, like the other human EHDs, undergoes serine-phosphorylation. Our results also indicate that EHD1 is a serum-inducible serine-phosphoprotein and that PKC (protein kinase C) is one of its kinases. In addition, we show that inhibitors of clathrin-mediated endocytosis decrease EHD1 phosphorylation, while inhibitors of caveolinmediated endocytosis do not affect EHD1 phosphorylation. The results of experiments in which inhibitors of endocytosis were employed strongly suggest that EHD1 phosphorylation occurs between early endosomes and the endocytic recycling compartment.

Dietary flavonoids inhibit the anticancer effects of the proteasome inhibitor bortezomib

Dietary flavonoids have many health-promoting actions, including anticancer activity via proteasome inhibition. Bor-tezomib is a dipeptide boronate proteasome inhibitor that has activity in the treatment of multiple myeloma but is not effective in chronic lymphocytic leukemia (CLL). Although CLL cells are sensitive in vitro to bortezomib-induced apoptosis when cultured in medium, the killing activity was blocked when cultured in 50% fresh autologous plasma. Dietary flavonoids, quercetin and myricetin, which are abundant in plasma, inhibited bortezomib-induced apoptosis of primary CLL and malignant B-cell lines in a dose-dependent manner. This inhibitory effect was associated with chemical reactions between quercetin and the boronic acid group, -RB(OH)2, in bortezomib. The addition of boric acid diminished the inhibitory effect of both quercetin and plasma on bortezomib-induced apoptosis. The protective effect was also reduced when myeloma cell lines, but not B-cell lines, were preincubated with quercetin, indicating a direct effect of quercetin on myeloma cells. At high doses, quercetin itself induced tumor cell death. These data indicate that dietary flavonoids limit the efficacy of bortezomib, whereas supplemental inorganic boric acid is able to reverse this. The complex interactions between quercetin, tumor cells, and bortezomib mean caution is required when giving dietary advice to patients.

Hsp90 inhibition has opposing effects on wild-type and mutant p53 and induces p21 expression and cytotoxicity irrespective of p53/ATM status in chronic lymphocytic leukaemia cells

In chronic lymphocytic leukaemia (CLL), mutation/deletion of TP53 is strongly associated with early disease progression, resistance to chemotherapy and short patient survival. Consequently, there is a pressing need to develop novel treatment protocols for this high-risk patient group. The present study was performed to evaluate Hsp90 inhibition as a possible therapeutic approach for such patients. Primary CLL cells of defined ataxia telangiectasia mutated (ATM)/p53 status were incubated with the Hsp90 inhibitor geldanamycin (GA) and analysed by western blotting for the expression of p53, p21, MDM2 and Akt. GA downregulated overexpressed mutant p53 protein (an oncogene) and upregulated wild-type (wt) p53 (a tumour suppressor). The upregulation of wt p53 by GA was independent of ATM and was accompanied by downregulation of Akt and the active form of MDM2, indicating a possible mechanism. GA also produced a p53/ATM-independent increase in the levels of p21-a potent inducer of cell-cycle arrest. In-vitro cytotoxicity studies showed that GA killed cultured CLL cells in a dose- and time-dependent fashion irrespective of their p53/ATM status and more effectively than normal blood mononuclear cells. In summary, our findings reveal important consequences of inhibiting Hsp90 in CLL cells and strongly support the therapeutic evaluation of Hsp90 inhibitors in poor-prognosis patients with p53 defects.

Albumin rescues ocular epithelial cells from cell death in dry eye

PURPOSE

Because autologous serum is useful for the treatment of severe dry eye, serum components may be a potential candidate for the treatment of dry eye. Serum albumin is abundantly contained in human serum and plays many physiologic roles. We investigated the efficacy of serum albumin in a dry eye animal model.

METHODS

Sprague-Dawley rats were used to make dry eye model rats according to a previous study. The central region of the corneal epithelium was scraped mechanically, and the rats were placed in a desiccation room (temperature, 23 +/- 2 degrees C; humidity, 28 +/- 2%; air flow, 2-4 m/s) for 12 hr. During desiccation, one eye of each rat was treated with human serum albumin eye drops, and the other eye was given a drop of phosphate buffered saline (PBS). Human corneal and conjunctival cell lines were used to investigate suppression effect of albumin on apoptosis induced by addition of apoptosis inducers or serum deprivation, respectively.

RESULTS

The erosion area was increased by 12 hr of desiccation. Albumin treatment decreased the area of erosion compared with PBS treatment. Apoptosis suppression assay using cell lines revealed that caspase-3 activation induced by serum deprivation and DNA fragmentation induced by addition of apoptosis inducers were dose-dependently suppressed by albumin.

CONCLUSIONS

Albumin showed a therapeutic effect in dry eye model rats. This efficacy may be related to the suppression of apoptosis by albumin.

The Akt signaling pathway determines the different proliferative capacity of chronic lymphocytic leukemia B-cells from patients with progressive and stable disease

Chronic lymphocytic leukemia (CLL) B-cells are hyporesponsive to many proliferative signals that induce activation of normal B-lymphocytes. However, a heterogeneous response has recently been observed with immunostimulatory CpG-oligodeoxynucleotides (CpG ODN). We now show that CpG ODN induce proliferation mainly in CLL B-cells from patients with progressive disease and unmutated immunoglobulin V(H) genes, whereas G(1)/S cell cycle arrest and apoptosis are induced in leukemic B-cells from stable/V(H) mutated CLL. Examination of early signaling events demonstrated that all CLL B-cells respond to CpG ODN stimulation by degradation of the NF-kappaB inhibitor IkappaB and activation of the Akt, ERK, JNK and p38 MAPK kinases, but the magnitude and duration of the signaling response was greater in the proliferating cases. Pharmacological inhibition of these pathways showed that simultaneous activation of Akt, ERK and JNK is required for cell cycle progression and proliferation. Conversely, introduction of constitutively active Akt in nonproliferating CLL B-cells resulted in induction of cyclin A following CpG ODN stimulation, indicating that increased Akt activation is sufficient to overcome the hyporesponsiveness of these cells to proliferative signals. Thus, the magnitude of Akt signaling may determine the distinct responses observed in leukemic B-cells belonging to the different prognostic subgroups.

Regulation of Akt/PKB by phosphatidylinositol 3-kinase-dependent and -independent pathways in B-cell chronic lymphocytic leukemia cells: role of protein kinase Cβ

Apoptosis of B cell chronic lymphocytic leukemia (B-CLL) cells is regulated by the PI-3K-Akt pathway. In the present work, we have analyzed the mechanisms of Akt phosphorylation in B-CLL cells. Freshly isolated cells present basal Akt phosphorylation, which is PI-3K-dependent, as incubation with the PI-3K inhibitor LY294002 decreased Ser-473 and Thr-308 phosphorylation in most samples analyzed (seven out of 10). In three out of 10 cases, inhibition of protein kinase C (PKC) inhibited basal Akt phosphorylation. Stromal cell-derived factor-1alpha, IL-4, and B cell receptor activation induced PI-3K-dependent Akt phosphorylation. PMA induced the phosphorylation of Akt at Ser-473 and Thr-308 and the phosphorylation of Akt substrates, independently of PI-3K in B-CLL cells. In contrast, PKC-mediated phosphorylation of Akt was PI-3K-dependent in normal B cells. Finally, a specific inhibitor of PKCbeta blocked the phosphorylation and activation of Akt by PMA in B-CLL cells. Taken together, these results suggest a model in which Akt could be activated by two different pathways (PI-3K and PKCbeta) in B-CLL cells.

Affinity separation of polyribonucleotide-binding human blood proteins

Using affinity columns with immobilized poly(A), poly(G), poly(U), poly(C), and poly(A).poly(U) and poly(G) x poly(C) duplexes several polyribonucleotide-binding blood plasma proteins have been captured. Albumin and keratins K1 and K2e have been detected to bind polypurine tracts. The in vitro glycated albumin binds poly(A) and poly(G) more efficiently than the unmodified protein. The major polypyrimidine-binding blood plasma protein (28 kDa) can catalyze the hydrolysis of poly(U).

Xanthohumol kills B-chronic lymphocytic leukemia cells by an apoptotic mechanism

B-chronic lymphocytic leukemia (B-CLL) is an indolent lymphoid malignancy with variable prognosis. Adverse prognostic factors comprise treatment resistance, cytogenetics (11q- and 17p-), the presence of unmutated Ig genes, and the more comprehensive activation marker Zap 70. In contrast to diminished sensitivity to chemotherapy, Zap 70+ B-CLL cells retain their responsiveness to manipulation of signal transduction and monoclonals. Xanthohumol (XA) has recently been documented to have an impact on breast cancer cell growth and invasiveness in vitro. Based on these observations, lymphocytes from patients with B-CLL were cultured in the presence of XA in vitro. XA induced a dose-dependent killing of B-CLL cells at an LD(50) ((24 h)) of 24.4 +/- 6.6 microM, independent of known adverse prognostic factors including functional loss of p53. Cell death was associated with poly (ADP)-ribose polymerase cleavage and annexin V positivity, suggestive of an apoptotic mechanism. Surprisingly, p 70(S 6 K) phosphorylation was stimulated upon XA treatment. In conclusion, XA has an antitumor activity on B-CLL cells in vitro. The molecular mechanisms behind this pro-apoptotic effect deserve further investigation.

Lower serum albumin concentration and change in muscle mass: the Health, Aging and Body Composition Study

BACKGROUND

Low albumin concentrations in older persons increase the risk of poor health outcomes, including functional decline.

OBJECTIVE

The aim of the study was to investigate the association between serum albumin concentration and skeletal muscle loss (sarcopenia) in old age.

DESIGN

Serum albumin concentration was measured in 1882 black and white men and women aged 70-79 y participating in the Health, Aging and Body Composition Study. Five-year changes in appendicular skeletal muscle mass (ASMM), total-body fat-free mass (FFM), and trunk lean mass (TLM) were measured by using dual-energy X-ray absorptiometry. Confounders included health and lifestyle factors, which are markers of inflammation and protein intake.

RESULTS

A low albumin concentration (< 38 g/L) was observed in 21.2% of the study participants. After adjustment for confounders, the mean (+/-SE) change in ASMM was -82 +/- 26 g per 3-g/L lower albumin concentration (P = 0.002). This association remained after persons with a low albumin concentration (< 38 g/L) were excluded. The decline in ASMM in subjects with low albumin concentrations was almost 30% higher (-930 +/- 56 g) than that in those with albumin concentrations > or = 42 g/L (-718 +/- 38 g; P < 0.01). The association between albumin and change in ASMM remained after additional adjustment for weight change. A weak association was observed for FFM, whereas no association was observed for TLM, which suggests a specific role of albumin in skeletal muscle change.

CONCLUSIONS

Lower albumin concentrations, even above the clinical cutoff of 38 g/L, are associated with future loss of ASMM in older persons. Low albumin concentration may be a risk factor for sarcopenia.

Evidence for distinct pathomechanisms in genetic subgroups of chronic lymphocytic leukemia revealed by quantitative expression analysis of cell cycle, activation, and apoptosis-associated genes

PURPOSE

In patients with chronic lymphocytic leukemia (CLL), the VH mutation status and genomic aberrations (13q-, +12q, 11q-, 17p-) identify distinct prognostic subgroups. The aim was to elucidate biologic mechanisms through which these genetic markers may exert their pathogenic influence.

PATIENTS AND METHODS

Twenty-four genes involved in apoptosis, cell cycle, B-cell activation, and B-cell receptor (BCR) signaling were analyzed by real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in 82 CLL cases constituting prototypic genetic CLL subgroups as defined by the VH mutation status and the genomic aberrations 13q-, +12, 11q-, and 17p-.

RESULTS

The VH mutation subgroups were characterized by a differential expression of the BCR associated genes ZAP70 and PI3K. Among the subgroups defined by genomic aberrations, there was a deregulation of candidate genes from the affected critical genomic regions such as CDK4 (up), ATM (down), and TP53 (down) in the groups +12, 11q-, and 17p-, respectively. Additionally, the genomic subgroups were characterized by a significant deregulation of cell cycle and apoptosis regulators: AKT (up) in 13q, E2F1 (up) in +12, MYC (up) and BCL-2 (down) in 17p-, and CCND3 (down) in 11q- as well as 17p-. The 17p- subgroup showed an additional down-regulation of BCR-associated genes such as SYK and PI3K.

CONCLUSION

The characteristic gene expression patterns observed implicate a differential regulation of cell cycle, apoptosis, and BCR signaling in the genetic subgroups illustrating distinct pathomechanisms and are evidence for a gene dosage effect being operative in CLL. These findings link the biologic diversity and clinical heterogeneity of CLL.

Selective Apoptotic Killing of Malignant Hemopoietic Cells by Antibody-Targeted Delivery of an Amphipathic Peptide

The alpha-helical amphipathic peptide D-(KLAKLAK)2 is toxic to eukaryotic cells if internalized by a suitable targeting mechanism. We have targeted this peptide to malignant hemopoietic cells via conjugation to monoclonal antibodies, which recognize lineage-specific cell surface molecules. An anti-CD19/peptide conjugate efficiently killed 3/3 B lymphoid lines. However, an anti-CD33/peptide conjugate was cytotoxic to only one of three CD33-positive myeloid leukemia lines. The IC50 towards susceptible lines were in the low nanomolar range. Conjugates were highly selective and did not kill cells that did not express the appropriate cell surface cognate of the antibody moiety. Anti-CD19/peptide conjugates efficiently killed cells from patients with chronic lymphocytic leukemia but anti-CD33/peptide reagents were less effective against fresh acute myeloid leukemia cells. We therefore suggest that amphipathic peptides may be of value as targeted therapeutic agents for the treatment of a subset of hematologic malignancies.

AT514, a cyclic depsipeptide from Serratia marcescens, induces apoptosis of B-chronic lymphocytic leukemia cells: interference with the Akt/NF-κB survival pathway

Clinical treatment of B-cell chronic lymphocytic leukemia (B-CLL) is limited by the progressive drug resistance and nonselectivity of most drugs towards malignant cells. Depsipeptides are present in certain bacteria and display potent antitumor activity. We have studied the effect of the novel cyclodepsipeptide AT514 (serratamolide) from Serratia marcescens on B-CLL cell viability. AT514 induced apoptosis of B-CLL cells from the 21 patients studied, as confirmed by Annexin-V binding and nuclei condensation, with an average IC50 of 13 microM. AT514 was effective in those B-CLL cases resistant to fludarabine, but had no effect on normal PBL. AT514 preferentially activated the intrinsic apoptotic pathway, as evidenced by loss of mitochondrial membrane potential, release of cytochrome c and activation of caspase-9 and -3, but not of caspase-8. Importantly, AT514 interfered with phosphatidylinositol-3 kinase and protein kinase C survival signals since it increased the apoptotic effect of LY294002 and Bisl inhibitors, and induced Akt dephosphorylation at Ser 473. AT514 also decreased NF-kappaB activity by dramatically reducing the levels of p65 in B-CLL. This was confirmed on functional assays using NF-kappaB-luc-transfected Raji cells and transgenic mice. Our results establish that AT514 induces apoptosis of primary B-CLL cells and could be useful for clinical treatment of this malignancy.

Sustained signaling through the B-cell receptor induces Mcl-1 and promotes survival of chronic lymphocytic leukemia B cells

The clinical course of chronic lymphocytic leukemia (CLL) differs significantly between patients with mutated (M-CLL) and unmutated (U-CLL) immunoglobulin (Ig) variable heavy-chain (V(H)) genes, implying a role for B-cell receptor (BCR) signaling in the pathogenesis of this disease. We have now investigated activation of downstream BCR signaling pathways in U-CLL and M-CLL B cells using soluble anti-IgM (sol-IgM) and immobilized anti-IgM (imm-IgM) antibodies as models for antigenic stimulation. Ligation of the BCR with sol-IgM induced incomplete responses in both CLL subsets, resembling the pattern described for tolerant B cells. This response was characterized by transient phosphorylation of extracellular signal-related kinase (ERK) and Akt (protein kinase B [PKB]), lack of activation of c-JUN NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), and variable activation of phospholipase Cgamma2 (PLCgamma2) and nuclear factor-kappaB (NF-kappaB). Stimulation with imm-IgM elicited a more complete BCR signal and significantly prolonged phosphorylation of ERK and Akt, indicating persistent or repetitive BCR signaling. Moreover, this type of stimulation increased the levels of the antiapoptotic protein myeloid cell leukemia-1 (Mcl-1) and protected from chemotherapy-induced apoptosis, whereas induction of apoptosis and down-regulation of Mcl-1 was observed following stimulation with sol-IgM. These data demonstrate that only sustained BCR signaling can promote survival of CLL B cells and indicate that the main difference between CLL with mutated and unmutated V(H) genes may reside in the availability of such stimulation.

Lysophosphatidic acid (LPA) protects primary chronic lymphocytic leukemia cells from apoptosis through LPA receptor activation of the anti-apoptotic protein AKT/PKB

Lysophosphatidic acid (LPA) protects epithelial and fibroblast cell lines from apoptosis. In B-cells, LPA acts as a growth factor promoting cell proliferation. Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of CD19+/CD5+ B-lymphocytes primarily through a block in apoptosis. The mechanisms underlying this defect are not fully understood. We investigated whether LPA could be a survival factor in CLL cells. Herein, we demonstrate that LPA protects B-cell lines BJAB and I-83 and primary CLL cells but not normal B-cells from fludarabine- and etoposide-induced apoptosis. Furthermore, LPA prevented spontaneous apoptosis in primary CLL cells. The LPA1 expression was found to be increased in primary CLL cells compared with normal B-cells correlating with LPA prevention of apoptosis. Treatment of primary CLL cells with the LPA receptor antagonist, diacylglycerol pyrophosphate, reverses the protective effect of LPA against apoptosis, and down-regulation of the LPA1 by siRNA blocked LPA-mediated protection against spontaneous apoptosis in primary CLL cells. The protective effect of LPA was inhibited by blocking activation of the phosphatidylinositol 3-kinase/AKT signaling pathway. These results indicate that LPA is a survival factor in B-cell lines and primary CLL cells but not normal B-cells. Thus, drugs targeting the LPA receptors might be an effective therapy against B-cell-derived malignancies such as CLL.