Development of a novel method for amniotic fluid stem cell storage

BACKGROUND AIMS

Current procedures for collection of human amniotic fluid stem cells (hAFSCs) indicate that cells cultured in a flask for 2 weeks can then be used for research. However, hAFSCs can be retrieved directly from a small amount of amniotic fluid that can be obtained at the time of diagnostic amniocentesis. The aim of this study was to determine whether direct freezing of amniotic fluid cells is able to maintain or improve the potential of a sub-population of stem cells.

METHODS

We compared the potential of the hAFSCs regarding timing of freezing, cells obtained directly from amniotic fluid aspiration (D samples) and cells cultured in a flask before freezing (C samples). Colony-forming-unit ability, proliferation, morphology, stemness-related marker expression, senescence, apoptosis and differentiation potential of C and D samples were compared.

RESULTS

hAFSCs isolated from D samples expressed mesenchymal stem cells markers until later passages, had a good proliferation rate and exhibited differentiation capacity similar to hAFSCs of C samples. Interestingly, direct freezing induced a higher concentration of cells positive for pluripotency stem cell markers, without teratoma formation in vivo.

CONCLUSIONS

This study suggests that minimal processing may be adequate for the banking of amniotic fluid cells, avoiding in vitro passages before the storage and exposure to high oxygen concentration, which affect stem cell properties. This technique might be a cost-effective and reasonable approach to the process of Good Manufacturing Process accreditation for stem-cell banks.

Human biliary tree stem/progenitor cells immunomodulation: Role of hepatocyte growth factor

AIM

Human biliary tree stem/progenitor cells (hBTSC) are multipotent epithelial stem cells with the potential for allogenic transplant in liver, biliary tree, and pancreatic diseases. Human mesenchymal stem cells, but also epithelial stem cells, are able to modulate immune responses with different types of secretion molecules.

METHODS

The initial aim of the present study was to develop for the first time a culture protocol in order to expand hBTSC in vitro through passages, allowing to maintain a similar stem cell and secretome profile. Furthermore, we investigated the secretome profile of the hBTSC to assess the production of molecules capable of affecting immune feedback.

RESULTS

We found that hepatocyte growth factor produced by hBTSC exerts its cytoprotective role inducing apoptosis in human immune cells, such as lymphocytes.

CONCLUSIONS

The present study, therefore, supports the hypothesis that hBTSC can be useful for the purpose of regenerative medicine, as they can be banked and expanded, and they can secrete immunoregulatory factors.

Apoptosis and inflammatory response in human astrocytes are induced by a transmissible cytotoxic agent of neurological origin

We demonstrated the presence of an in vitro transmissible cytotoxic agent (TCA) in the cerebrospinal fluid (CSF) of patients with different acute neurological diseases. The nature of this agent is still a matter of study since repeated attempts have failed to identify it as a conventional infectious agent. Here, we describe the mechanisms through which TCA affects human astrocytes, demonstrating: a late apoptotic process, mediated by caspases 9 and 3 activation, involving the Bcl2-Bak-axis; an early and late p38 MAPK activation; an interference with the IL-8 and MCP-1 secretory response. These in vitro data provide initial evidence of TCA involvement as a pro-apoptotic and pro-inflammatory signal, directly affecting astrocytic behavior. The implications of these findings in certain neurological diseases will be discussed.

Reversal of the glycolytic phenotype of primary effusion lymphoma cells by combined targeting of cellular metabolism and PI3K/Akt/ mTOR signaling

PEL is a B-cell non-Hodgkin lymphoma, occurring predominantly as a lymphomatous effusion in body cavities, characterized by aggressive clinical course, with no standard therapy. Based on previous reports that PEL cells display a Warburg phenotype, we hypothesized that the highly hypoxic environment in which they grow in vivo makes them more reliant on glycolysis, and more vulnerable to drugs targeting this pathway. We established here that indeed PEL cells in hypoxia are more sensitive to glycolysis inhibition. Furthermore, since PI3K/Akt/mTOR has been proposed as a drug target in PEL, we ascertained that pathway-specific inhibitors, namely the dual PI3K and mTOR inhibitor, PF-04691502, and the Akt inhibitor, Akti 1/2, display improved cytotoxicity to PEL cells in hypoxic conditions. Unexpectedly, we found that these drugs reduce lactate production/extracellular acidification rate, and, in combination with the glycolysis inhibitor 2-deoxyglucose (2-DG), they shift PEL cells metabolism from aerobic glycolysis towards oxidative respiration. Moreover, the associations possess strong synergistic cytotoxicity towards PEL cells, and thus may reduce adverse reaction in vivo, while displaying very low toxicity to normal lymphocytes. Finally, we showed that the association of 2-DG and PF-04691502 maintains its cytotoxic and proapoptotic effect also in PEL cells co-cultured with human primary mesothelial cells, a condition known to mimic the in vivo environment and to exert a protective and pro-survival action. All together, these results provide a compelling rationale for the clinical development of new therapies for the treatment of PEL, based on combined targeting of glycolytic metabolism and constitutively activated signaling pathways.

NADPH oxidase-4 and MATER expressions in granulosa cells: Relationships with ovarian aging

AIMS

Relevant roles in follicular development and ovulation are played by maternal antigen that embryos require (MATER), product of a maternal effect gene, and by reactive oxygen species (ROS), indispensable for the induction of ovulatory genes. At the moment, the relationship between these two biological systems and their involvement in the ovarian aging have not been still clarified. The aim of the current experimental study was to analyse the age-related changes of the MATER and NOX proteins.

MATERIALS AND METHODS

MATER and ROS homeostasis was studied in granulosa cells (GCs) and cumulus cells (CCs) of infertile patients who undergone oocyte retrieval for in vitro fertilization cycles using Western blot and confocal immunofluorescence analysis. Samples were obtained from subjects with age≥40years (cases) and with age≤37years (controls).

KEY FINDINGS

The expression pattern of MATER and NOX observed in GCs was not different from that observed in CCs. High levels of both proteins were detected in the control samples. A significant lower expression of both MATER and NOX4 was observed in the case versus control samples.

SIGNIFICANCE

The expression of MATER and NOX4 proteins are closely related to the follicular development and ovulation with particular regard for ovarian aging.

Inhibition of Lon protease by triterpenoids alters mitochondria and is associated to cell death in human cancer cells

Mitochondrial Lon protease (Lon) regulates several mitochondrial functions, and is inhibited by the anticancer molecule triterpenoid 2-cyano-3, 12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), or by its C-28 methyl ester derivative (CDDO-Me). To analyze the mechanism of action of triterpenoids, we investigated intramitochondrial reactive oxygen species (ROS), mitochondrial membrane potential, mitochondrial mass, mitochondrial dynamics and morphology, and Lon proteolytic activity in RKO human colon cancer cells, in HepG2 hepatocarcinoma cells and in MCF7 breast carcinoma cells. We found that CDDO and CDDO-Me are potent stressors for mitochondria in cancer cells, rather than normal non-transformed cells. In particular, they: i) cause depolarization; ii) increase mitochondrial ROS, iii) alter mitochondrial morphology and proteins involved in mitochondrial dynamics; iv) affect the levels of Lon and those of aconitase and human transcription factor A, which are targets of Lon activity; v) increase level of protein carbonyls in mitochondria; vi) lead to intrinsic apoptosis. The overexpression of Lon can rescue cells from cell death, providing an additional evidence on the role of Lon in conditions of excessive stress load.

Stem cells isolated from human dental pulp and amniotic fluid improve skeletal muscle histopathology in mdx/SCID mice

INTRODUCTION

Duchenne muscular dystrophy (DMD), caused by a lack of the functional structural protein dystrophin, leads to severe muscle degeneration where the patients are typically wheelchair-bound and die in their mid-twenties from cardiac or respiratory failure or both. The aim of this study was to investigate the potential of human dental pulp stem cells (hDPSCs) and human amniotic fluid stem cells (hAFSCs) to differentiate toward a skeletal myogenic lineage using several different protocols in order to determine the optimal conditions for achieving myogenic commitment and to subsequently evaluate their contribution in the improvement of the pathological features associated with dystrophic skeletal muscle when intramuscularly injected into mdx/SCID mice, an immune-compromised animal model of DMD.

METHODS

Human DPSCs and AFSCs were differentiated toward myogenic lineage in vitro through the direct co-culture with a myogenic cell line (C2C12 cells) and through a preliminary demethylation treatment with 5-Aza-2'-deoxycytidine (5-Aza), respectively. The commitment and differentiation of both hDPSCs and hAFSCs were evaluated by immunofluorescence and Western blot analysis. Subsequently, hDPSCs and hAFSCs, preliminarily demethylated and pre-differentiated toward a myogenic lineage for 2 weeks, were injected into the dystrophic gastrocnemius muscles of mdx/SCID mice. After 1, 2, and 4 weeks, the gastrocnemius muscles were taken for immunofluorescence and histological analyses.

RESULTS

Both populations of cells engrafted within the host muscle of mdx/SCID mice and through a paracrine effect promoted angiogenesis and reduced fibrosis, which eventually led to an improvement of the histopathology of the dystrophic muscle.

CONCLUSION

This study shows that hAFSCs and hDPSCs represent potential sources of stem cells for translational strategies to improve the histopathology and potentially alleviate the muscle weakness in patients with DMD.

Role of hepatocyte growth factor in the immunomodulation potential of amniotic fluid stem cells

Human amniotic fluid stem cells (hAFSCs) may be useful for regenerative medicine because of their potential to differentiate into all three germ layers and to modulate immune response with different types of secretion molecules. This last issue has not been completely elucidated. The aim of this study was to investigate the secretome profile of the hAFSC, focusing on the role of hepatocyte growth factor (HGF) in immunoregulation through short and long cocultures with human peripheral blood mononuclear cells. We found that HGF produced by hAFSCs exerts a cytoprotective role, inducing an increase in caspase-dependent apoptosis in human immune cells. This study provides evidence supporting the hypothesis that amniotic fluid is an ideal source of stem cells for expansion and banking properties for therapeutic use. hAFSCs not only are less immunogenic but also can secrete immunoregulatory factors that may be useful in autoimmune diseases or allogenic implants.

SIGNIFICANCE

New information about the secretome pattern is reported in this paper. Human amniotic fluid stem cells (hAFSCs) possess immunomodulatory properties involving hepatocyte growth factor production. hAFSCs could be used in immunotherapies and might be able to avoid allogenic rejection.

Critical-size bone defect repair using amniotic fluid stem cell/collagen constructs: effect of oral ferutinin treatment in rats

AIMS

This study aims to evaluate the bone regeneration in a rat calvarias critical size bone defect treated with a construct consisting of collagen type I and human amniotic fluid stem cells (AFSCs) after oral administration of phytoestrogen ferutinin.

MAIN METHODS

In 12 week old male rats (n=10), we performed two symmetric full-thickness cranial defects on each parietal region, and a scaffold was implanted into each cranial defect. The rats were divided into four groups: 1) collagen scaffold, 2) collagen scaffold+ferutinin at a dose of 2mg/kg/5 mL, 3) collagen scaffold + AFSCs, and 4) collagen scaffold + AFSCs + ferutinin. The rats were sacrificed after 4 weeks, and the calvariae were removed, fixed, embedded in paraffin and cut into 7 μm thick sections. Histomorphometric measures, immunohistochemical and immunofluorescence analyses were performed on the paraffin sections.

KEY FINDINGS

The histomorphometric analysis on H&E stained sections showed a significant increase in the regenerated area of the 4th group compared with the other groups. Immunohistochemistry performed with a human anti-mitochondrial antibody showed the presence of AFSCs 4 weeks after the transplant. Immunofluorescence analysis revealed the presence of osteocalcin and estrogen receptors (ERα and GPR30) in all groups, with a greater expression of all markers in samples where the scaffold was treated with AFSCs and the rats were orally administered ferutinin.

SIGNIFICANCE

Our results demonstrated that the oral administration of ferutinin is able to improve the bone regeneration of critical-size bone defects in vivo that is obtained with collagen-AFSCs constructs.

In vitro differentiation into insulin-producing β-cells of stem cells isolated from human amniotic fluid and dental pulp

AIM

To investigate the ability of human amniotic fluid stem cells and human dental pulp stem cells to differentiate into insulin-producing cells.

METHODS

Human amniotic fluid stem cells and human dental pulp stem cells were induced to differentiate into pancreatic β-cells by a multistep protocol. Islet-like structures were assessed in differentiated human amniotic fluid stem cells and human dental pulp stem cells after 21 days of culture by dithizone staining. Pancreatic and duodenal homebox-1, insulin and Glut-2 expression were detected by immunofluorescence and confocal microscopy. Insulin secreted from differentiated cells was tested with SELDI-TOF MS and by enzyme-linked immunosorbent assay.

RESULTS

Human amniotic fluid stem cells and human dental pulp stem cells, after 7 days of differentiation started to form islet-like structures that became evident after 14 days of induction. SELDI-TOF MS analysis, revealed the presence of insulin in the media of differentiated cells at day 14, further confirmed by enzyme-linked immunosorbent assay after 7, 14 and 21 days. Both stem cell types expressed, after differentiation, pancreatic and duodenal homebox-1, insulin and Glut-2 and were positively stained by dithizone. Either the cytosol to nucleus translocation of pancreatic and duodenal homebox-1, either the expression of insulin, are regulated by glucose concentration changes. Day 21 islet-like structures derived from both human amniotic fluid stem cells and human dental pulp stem cell release insulin in a glucose-dependent manner.

CONCLUSION

The present study demonstrates the ability of human amniotic fluid stem cells and human dental pulp stem cell to differentiate into insulin-producing cells, offering a non-pancreatic, low-invasive source of cells for islet regeneration.

Human amniotic fluid-derived and dental pulp-derived stem cells seeded into collagen scaffold repair critical-size bone defects promoting vascularization

Introduction

The main aim of this study is to evaluate potential human stem cells, such as dental pulp stem cells and amniotic fluid stem cells, combined with collagen scaffold to reconstruct critical-size cranial bone defects in an animal model.

Methods

We performed two symmetric full-thickness cranial defects on each parietal region of rats and we replenished them with collagen scaffolds with or without stem cells already seeded into and addressed towards osteogenic lineage in vitro. After 4 and 8 weeks, cranial tissue samples were taken for histological and immunofluorescence analysis.

Results

We observed a new bone formation in all of the samples but the most relevant differences in defect correction were shown by stem cell–collagen samples 4 weeks after implant, suggesting a faster regeneration ability of the combined constructs. The presence of human cells in the newly formed bone was confirmed by confocal analysis with an antibody directed to a human mitochondrial protein. Furthermore, human cells were found to be an essential part of new vessel formation in the scaffold.

Conclusion

These data confirmed the strong potential of bioengineered constructs of stem cell–collagen scaffold for correcting large cranial defects in an animal model and highlighting the role of stem cells in neovascularization during skeletal defect reconstruction.

Human serum promotes osteogenic differentiation of human dental pulp stem cells in vitro and in vivo

Human dental pulp is a promising alternative source of stem cells for cell-based tissue engineering in regenerative medicine, for the easily recruitment with low invasivity for the patient and for the self-renewal and differentiation potential of cells. So far, in vitro culture of mesenchymal stem cells is usually based on supplementing culture and differentiation media with foetal calf serum (FCS). FCS is known to contain a great quantity of growth factors, and thus to promote cell attachment on plastic surface as well as expansion and differentiation. Nevertheless, FCS as an animal origin supplement may represent a potential means for disease transmission besides leading to a xenogenic immune response. Therefore, a significant interest is focused on investigating alternative supplements, in order to obtain a sufficient cell number for clinical application, avoiding the inconvenients of FCS use. In our study we have demonstrated that human serum (HS) is a suitable alternative to FCS, indeed its addition to culture medium induces a high hDPSCs proliferation rate and improves the in vitro osteogenic differentiation. Furthermore, hDPSCs-collagen constructs, pre-differentiated with HS-medium in vitro for 10 days, when implanted in immunocompromised rats, are able to restore critical size parietal bone defects. Therefore these data indicate that HS is a valid substitute for FCS to culture and differentiate in vitro hDPSCs in order to obtain a successful bone regeneration in vivo.

Fibroin scaffold repairs critical-size bone defects in vivo supported by human amniotic fluid and dental pulp stem cells

The main aim of this study was the comparative evaluation of fibroin scaffolds combined with human stem cells, such as dental pulp stem cells (hDPSCs) and amniotic fluid stem cells (hAFSCs), used to repair critical-size cranial bone defects in immunocompromised rats. Two symmetric full-thickness cranial defects on each parietal region of rats have been replenished with silk fibroin scaffolds with or without preseeded stem cells addressed toward osteogenic lineage in vitro. Animals were euthanized after 4 weeks postoperatively and cranial tissue samples were taken for histological analysis. The presence of human cells in the new-formed bone was confirmed by confocal analysis with an antibody directed to a human mitochondrial protein. Fibroin scaffolds induced mature bone formation and defect correction, with higher bone amount produced by hAFSC-seeded scaffolds. Our findings demonstrated the strong potential of stem cells/fibroin bioengineered constructs for correcting large cranial defects in animal model and is likely a promising approach for the reconstruction of human large skeletal defects in craniofacial surgery.

Human amniotic fluid stem cells seeded in fibroin scaffold produce in vivo mineralized matrix

This study investigated the potential of amniotic fluid stem cells (AFSCs) to synthesize mineralized extracellular matrix (ECM) within different porous scaffolds of collagen, poly-D,L-lactic acid (PDLLA), and silk fibroin. The AFSCs were initially differentiated by using an osteogenic medium in two-dimensional culture, and expression of specific bone proteins and the physiologic mineral production by the AFSCs were analyzed. In particular, during differentiation process, AFSCs expressed proteins like Runt-related transcription factor 2 (Runx2), Osterix, Osteopontin, and Osteocalcin with a sequential expression, analogous to those occurring during osteoblast differentiation, and produced extracellular calcium stores. AFSCs were then cultured on three-dimensional (3D) scaffolds and evaluated for their ability to differentiate into osteoblastic cells in vivo. Stem cells were cultured in vitro for 1 week in collagen, fibroin, and PDLLA scaffolds. The effect of predifferentiation of the stem cells in scaffolds on the subsequent bone formation in vivo was determined in a rat subcutaneous model. With the addition of a third dimension, osteogenic differentiation and mineralized ECM production by AFSCs were significantly higher. This study demonstrated the strong potential of AFSCs to produce 3D mineralized bioengineered constructs in vivo and suggests that fibroin may be an effective scaffold material for functional repair of critical size bone defects.

A novel biomarker harvesting nanotechnology identifies Bak as a candidate melanoma biomarker in serum

BACKGROUND

Melanoma represents only 4% of all skin cancers, but nearly 80% of skin cancer deaths. This manuscript applies several new measurement technologies with the purpose of elucidating molecular signatures of melanoma aggressiveness.

PURPOSE

We sought to determine whether low-abundant serum proteins related to apoptotic pathways could be measured and correlated with defined melanoma subtypes. Hydrogel core shell nanoparticles, a new technology capable of selectively entrapping low molecular weight proteins and protecting them from enzymatic degradation, were used to capture candidate serum biomarkers. Biomarker levels were correlated with confocal microscopy, thereby representing a combination of new technologies for in vivo histologic documentation.

RESULTS

Among a panel of analyzed serum proteins, Bak was differentially expressed between nevi and melanomas. Melanomas with higher Bak serum levels exhibited more pronounced junctional activity on confocal imaging, whereas lesions with 'sparse' dermal nests had weak Bak expression.

CONCLUSIONS

Our study links serum proteome analysis with confocal microscopic clinical in vivo histologic classification of melanomas. Bak has not been previously measured in serum. Bak differential expression among melanoma subtypes confirms the importance of the apoptotic pathway as a contributor to melanoma aggressiveness.

A novel biomarker harvesting nanotechnology identifies Bak as a candidate melanoma biomarker in serum

BACKGROUND

Melanoma represents only 4% of all skin cancers, but nearly 80% of skin cancer deaths. This manuscript applies several new measurement technologies with the purpose of elucidating molecular signatures of melanoma aggressiveness.

PURPOSE

We sought to determine whether low-abundant serum proteins related to apoptotic pathways could be measured and correlated with defined melanoma subtypes. Hydrogel core shell nanoparticles, a new technology capable of selectively entrapping low molecular weight proteins and protecting them from enzymatic degradation, were used to capture candidate serum biomarkers. Biomarker levels were correlated with confocal microscopy, thereby representing a combination of new technologies for in vivo histologic documentation.

RESULTS

Among a panel of analyzed serum proteins, Bak was differentially expressed between nevi and melanomas. Melanomas with higher Bak serum levels exhibited more pronounced junctional activity on confocal imaging, whereas lesions with 'sparse' dermal nests had weak Bak expression.

CONCLUSIONS

Our study links serum proteome analysis with confocal microscopic clinical in vivo histologic classification of melanomas. Bak has not been previously measured in serum. Bak differential expression among melanoma subtypes confirms the importance of the apoptotic pathway as a contributor to melanoma aggressiveness.

Reverse-phase protein microarrays (RPPA) as a diagnostic and therapeutic guide in multidrug resistant leukemia

Reverse-phase microarray assays using phospho-specific antibodies (RPPA) can directly measure levels of phosphorylated protein isoforms. In the current study, lysates from parental and multidrug resistant (MDR) CEM leukemia cells were spotted onto reverse-phase protein microarrays and probed with a panel of phospho-antibodies to ERK, PCK and Akt pathways. In particular, the Akt pathway is considered to play significant roles in leukemia and Akt inhibitor therapy has been proposed as a potential tool in the treatment of this disease. The RPPA data prompted us to investigate deeper this pathway. Here, we found that whereas total Akt1 protein level is higher in parental CEM cells, the activated isoform content, p-Akt1, increases in doxorubicin-selected CEM cells (MDR-CEM). This was backed up by Western blot analysis, confirming that Akt1 activity/phosphorylation may be up-regulated in MDR-CEM cells. Further exploration of inhibitory therapy in this system was evaluated. The TNF-related apoptosis-inducing ligand, TRAIL, has been shown to selectively kill tumor cells. Herein, we describe that in MDR-CEM cells TRAIL responsiveness correlates with a reduced expression of endogenous Akt1, suggesting that the MDR phenotype associated to P-gp sensitizes cells to TRAIL therapy.

Altered expression of apoptosis biomarkers in human colorectal microadenomas

Human colorectal microadenomas are considered the earliest detectable premalignant lesions in the colon. They can be identified as aggregates of enlarged crypts with thicker epithelial linings and elongated luminal openings on the colonic mucosal surface after methylene blue staining and observation under a dissecting microscope. Multiple lines of evidence suggest that a central role in neoplastic development is played by the inhibition of apoptosis, followed by disruption of DNA repair. Understanding the early mechanisms of colorectal carcinogenesis may help develop new approaches of colorectal cancer prevention and treatment. The aim of the present study was to quantify poly-ADP ribose polymerase 1 (PARP-1)-positive cells and to evaluate apoptotic control mechanisms through Caspase-3 active and Bcl-2 protein expression in human microadenomas and in normal colorectal mucosa using immunofluorescence techniques coupled with confocal microscopy and immunoblot experiments. The mean percentage of PARP-1-positive epithelial cells was 3.0 +/- 0.37% (SD) and 15.67 +/- 0.40% in microadenoma and in normal mucosa, respectively. Proteins involved in programmed cell death were differently expressed in microadenoma and in normal mucosa. Indeed, by semiquantitative immunofluorescence analysis, confirmed by Western blot, microadenoma showed low levels of Caspase-3 active and high levels of Bcl-2 expression, whereas the opposite was true for normal colorectal mucosa [corrected]. In the stroma of normal colorectal mucosa, fibroblast-like cells and neutrophils were the cells that underwent apoptosis to a greater extent. In conclusion, malfunction of the control mechanisms of programmed cell death seems present in the early stages of colorectal cancer development.

A-type lamins and signaling: the PI 3-kinase/Akt pathway moves forward

Lamin A/C is a nuclear lamina constituent mutated in a number of human inherited disorders collectively referred to as laminopathies. The occurrence and significance of lamin A/C interplay with signaling molecules is an old question, suggested by pioneer studies performed in vitro. However, this relevant question has remained substantially unanswered, until data obtained in cellular and organismal models of laminopathies have indicated two main aspects of lamin A function. The first aspect is that lamins establish functional interactions with different protein platforms, the second aspect is that lamin A/C activity and altered function may elicit different effects in different cells and tissue types and even in different districts of the same tissue. Both these observations strongly suggest that signaling mechanisms targeting lamin A/C or its binding partners may regulate such a plastic behavior. A number of very recent data show involvement of kinases, as Akt and Erk, or phosphatases, as PP1 and PP2, in lamin A-linked cellular mechanisms. Moreover, altered activation of signaling in laminopathies and rescue of the pathological phenotype in animal models by inhibitors of signaling pathways, strongly suggest that signaling effectors related to lamin A/C may be implicated in the pathogenesis of laminopathies and may represent targets of therapeutic intervention. In face of such an open perspective of basic and applied research, we review current evidence of lamin A/C interplay with signaling molecules, with particular emphasis on the lamin A-Akt interaction and on the biological significance of their relationship.

Cyclooxygenase-2 and Hypoxia-Inducible Factor-1alpha protein expression is related to inflammation, and up-regulated since the early steps of colorectal carcinogenesis

Chronic mucosal inflammation is considered a risk factor for colorectal cancer. Neutrophils are a major source of oxidants, whereas cyclooxygenase 2 (COX-2) and Hypoxia Inducible Factor-1alpha (HIF-1alpha) protein expression levels are increased in inflammatory and malignant lesions. The main purpose of the present study was to evaluate myeloperoxidase (MPO) positive cell infiltration, COX-2 and HIF-1alpha protein expression in colorectal carcinogenesis, especially in its early phases, using immunohistochemistry and immunofluorescence confocal microscopy techniques. MPO, COX-2 and HIF-1alpha proteins were expressed at higher rates in the normal colorectal mucosa of patients with inflammatory bowel diseases and colorectal tumours than in patients with normal colonoscopy. A gradual increase in COX-2 and HIF-1alpha protein expression was observed in dysplastic aberrant crypt foci, adenomas and carcinomas, showing a strong relation to dysplasia. In conclusion, the present study supports the hypothesis of a key role of inflammation in malignant transformation of colorectal mucosa. The evaluation of some early markers related to inflammation in the mucosa of the large bowel may serve as potential tool for prognosis and therapeutic strategies.

The oral protein-kinase C beta inhibitor enzastaurin (LY317615) suppresses signalling through the AKT pathway, inhibits proliferation and induces apoptosis in multiple myeloma cell lines

Deregulation of the protein kinase C (PKC) signalling pathway has been implicated in tumor progression. Here we investigated the PKC inhibitor enzastaurin for its activity against multiple myeloma (MM) cells. Enzastaurin suppresses cell proliferation in a large panel of human myeloma cell lines (HMCLs), with IC50 values ranging from 1.3 to 12.5 microM and induces apoptosis, which is prevented by the ZVAD-fmk broad caspase inhibitor. These results are consistent with decreased phosphorylation of AKT and GSK3-beta, a downstream target of the AKT pathway and a pharmacodynamic marker for enzastaurin. Furthermore, enzastaurin cytotoxicity is retained when HMCLs were cocultured with multipotent mesenchymal stromal cells. Enzastaurin has additive or synergistic cytotoxic effects with bortezomib or thalidomide. Considering the strong anti-myeloma activity of enzastaurin in vitro and in animal models and its safe toxicity profile, phase II studies in MM patients of enzastaurin alone or in combination with other drugs are warranted.

Propagation of a transmissible cytotoxic activity on cultures of human peripheral blood lymphocytes

Positive results were attained when human peripheral blood lymphocytes (PBLs) were investigated for their ability to propagate a transmissible cytotoxic activity (TCA) isolated on VERO cell cultures from a sample of cerebrospinal fluid (CSF) drawn from a woman with ischemic brain injury. In consideration of this finding it can be assumed that "in vivo" blood lymphocytes contributed to give rise to the TCA detected "in vitro" in the CSF inoculum.

Subcellular localization of beta-catenin and APC proteins in colorectal preneoplastic and neoplastic lesions

Adenomatous polyposis coli (APC) is a tumor suppressor gene whose main function is the destabilization of beta-catenin, a key effector of the Wnt signaling pathway. This gene is defective in familial adenomatous polyposis (FAP), a dominantly inherited disease, but inactivation of APC has been reported also in most sporadic colorectal tumors and it is considered an early event in colorectal tumorigenesis. The aim of the present study was to evaluate the intracellular ultrastructural distribution of beta-catenin and APC proteins in epithelial cells of normal colorectal mucosa, aberrant crypt foci (ACF, an early premalignant lesion) and cancer. We used the immunogold electron microscopic method to identify both proteins. Normal colonic epithelial cells showed a strong membranous expression of beta-catenin and lacked cytoplasmic and nuclear expression. Normal cells showed APC localization pattern characterized by diffuse nuclear expression and along the plasma membrane. In ACF and in carcinoma an absent or reduced membranous expression of beta-catenin was associated with an increased nuclear and cytoplasmatic expression. In aberrant crypt foci and carcinoma, APC was evident inside the nucleus and at the level of cell-cell junctions, but it was decreased in the cytoplasm. This method allowed the accurate localization of proteins of the Wnt signaling pathway in the early steps of colorectal carcinogenesis. The similar pattern of subcellular distribution of APC and beta-catenin in dysplastic ACF and colorectal cancer suggests that ACF are precursor lesions of sporadic and FAP-associated colorectal carcinoma.

Cell culture isolation of a transmissible cytotoxicity from a human sample of cerebrospinal fluid

We investigated a transmissible cytotoxicity isolated in VERO cell cultures from a sample of cerebrospinal fluid (CSF) drawn from a woman with ischemic brain injury. Amorphous aggregates formed by subunities of approximately 11 nm of diameter were detected in ultracentrifugates from partially purified cytotoxic cell preparations in the absence of virion-like particles which might justify the trasmissibility of this cytotoxic activity. Results of chemico-physical studies provided indications on the presence in the CSF of two protease-resistant acidic glycoproteins of about 39 and 27 kDa, respectively. The conformational change of a proteinic molecule may associate with particular properties such as tendency to aggregation, resistance to proteolysis, cytotoxicity. Considering that these same properties are shared by proteins present in the CSF sample under study, a hypothesis to pursue is that the CSF inoculum we isolated contained misfolded proteins formed in vivo following the ischemic injury of brain tissue. As far as the in vitro transmissibility of the cytotoxic activity, this could take place following the reproduction of the alterations of those proteins, independently of the original cause(s) which have fostered their formation in vivo.

Sensitization of multidrug resistant human ostesarcoma cells to Apo2 Ligand/TRAIL-induced apoptosis by inhibition of the Akt/PKB kinase

Chemotherapeutic agents have been used for the treatment of patients with osteosarcoma (OS). However, inherent or acquired resistance to these agents is a serious problem in the management of OS patients. The emergence of the multidrug resistance (MDR) phenotype in cancer cells is often associated with the overexpression of P-glycoprotein, encoded by the multidrug resistance gene MDR-1. The administration of some of the most common chemotherapeutic agents to these cells becomes ineffective because of their P-gp-driven efflux from the cell. Apo2L/TRAIL is a member of the tumor necrosis factor (TNF) family of cytokines that is considered to induce death of cancer cells but not normal cells. Its powerful apoptotic activity is mediated through its cell surface death domain-containing receptors, TRAIL-R1/DR4 and TRAIL-R2/DR5, which in turn spread the signal in the cytosol through the activation of the caspase cascade. The Akt/PKB kinase is an important cell survival protein which is regulated by D3-phosphoinositides. High Akt expression and activity levels are well documented in many types of tumors, which very often show an altered PI3-K/Akt/PTEN pathway. In this study the U2OS human osteosarcoma cell line and its multidrug resistant (MDR) subline that overexpresses MDR-1 gene, MDR-U2OS, have been analyzed for their responsiveness to TRAIL. In conflict with the presence of active DR4 and DR5 receptors in both clones, U2OS cells exhibited only a low responsiveness to TRAIL, while the MDR-U2OS subline did exhibit a marked TRAIL sensitivity. An analysis of the post-receptor events showed that TRAIL responsiveness correlates with a reduced expression of endogenous Akt. In fact, expression in MDR-U2OS cells of a constitutively active Akt strongly decreased their sensitivity to TRAIL. The identification of Akt as a key modulator of TRAIL responsiveness could help to design TRAIL-based combinations for treatment of osteosarcoma. Moreover, the discovery that multidrug resistant osteosarcomas are highly sensitive to TRAIL-induced apoptosis indicates TRAIL as a new candidate for the treatment of multidrug resistant bone malignancies.

Inducible nitric oxide synthase (iNOS) in immune-mediated demyelination and Wallerian degeneration of the rat peripheral nervous system

The inducible isoform of nitric oxide synthase (iNOS), produces nitric oxide (NO) from l-arginine in response to inflammatory stimuli. NO sub-serves different functions from cytotoxicity to neuroprotection and triggers either necrosis or apoptosis. This study shows by Northern blot analysis that during experimental allergic neuritis (EAN), at the beginning of clinical signs, there is a transient extensive iNOS mRNA induction in nerve roots, in which morphology is mainly characterized by severe demyelination, but not in sciatic nerve, where scattered axonal degeneration is evident. Immunocytochemistry performed on teased nerve fibers and ultrastructural analysis showed that iNOS was localized in both inflammatory and Schwann cells, and the study of cell membrane permeability detected with fluorescent dyes showed a diffuse necrotic phenotype in the whole peripheral nervous system (PNS). With EAN clinical progression toward spontaneous recovery, endoneurial iNOS was rapidly down-regulated and in nerve roots almost all cells shifted their membrane permeability to an apoptotic phenotype, while necrosis persisted in sciatic nerve, until complete clinical recovery, when both root and nerve returned to normal. During wallerian degeneration following sciatic nerve transection, iNOS was undetectable in PNS, while endoneurial cell membrane had a diffuse necrotic phenotype. These data support the hypothesis that, during cell-mediated demyelination, iNOS may influence Schwann cell-axon relationship causing axonal damage and regulating endoneurial cell life and death.

Developmental expression and subcellular localization of mouse MATER, an oocyte-specific protein essential for early development

We reported previously that Mater is a maternal effect gene that is required for early embryonic development beyond the two-cell stage in mice. Here we show the expressional profile of Mater and its protein during oogenesis and embryogenesis as well as its subcellular localization in oocytes. Mater mRNA was detectable earliest in oocytes of type 2 follicles, whereas MATER protein appeared earliest in oocytes of type 3a primary follicles. Both mRNA and protein accumulated during oocyte growth. In situ hybridization showed that Mater mRNA appeared progressively less abundant in oocytes beyond type 5a primary follicles. By ribonuclease protection assay, Mater mRNA was abundant in germinal vesicle oocytes, but was undetectable in all stages of preimplantation embryos. In contrast, the protein persisted throughout preimplantation development. Immunogold electron microscopic analysis revealed that MATER was located in oocyte mitochondria and nucleoli, and close to nuclear pores. Taken together, our data indicate that Mater gene transcription and protein translation are active during oogenesis, but appear inactive during early embryogenesis. Thus, Mater and its protein are expressed in a manner typical of maternal effect genes. The presence of MATER protein in mitochondria and nucleoli suggests that it may participate in both cytoplasmic and nuclear events during early development.

Apoptosis during intramembranous ossification

This paper concerns the role of apoptosis during the onset of bone histogenesis. Previous investigations by us performed on intramembranous ossification revealed the existence of two types of osteogenesis: static (SBF) and dynamic bone formation (DBF). During SBF, the first to occur, stationary osteoblasts transform into osteocytes in the same location where they differentiated, forming the primary spongiosa. DBF takes place later, when movable osteoblastic laminae differentiate along the surface of the primary trabeculae. The main distinctive feature between SBF and DBF is that the latter involves the invasion of pre-existing adjacent tissue, whereas the former does not. To ascertain whether programmed cell death during the invasive DBF process determines the fate of surrounding pre-existing mesenchyme differently from that occurring during the non-invasive SBF process, we studied apoptosis in ossification centres of tibial diaphysis in chick embryos and newborn rabbits with TUNEL and TEM. It emerged that, in both SBF and DBF, apoptosis affects mesenchymal cells located between the forming trabeculae and capillaries. However, apoptotic cells were observed more frequently during DBF than during SBF. This suggests that, during bone histogenesis, apoptosis, which is mostly associated with the invasive process of DBF, is probably dedicated to making space for advancing bone growth.

Interleukin-1-receptor-associated kinase 2 (IRAK2)-mediated interleukin-1-dependent nuclear factor kappaB transactivation in Saos2 cells requires the Akt/protein kinase B kinase

The post-receptor pathway that leads to nuclear factor kappaB (NF-kappaB) activation begins with the assembly of a membrane-proximal complex among the interleukin 1 (IL-1) receptors and the adaptor molecules, myeloid differentiation protein 88 (MyD88), IL-1-receptor-associated kinases (IRAKs) and tumour-necrosis-factor-receptor-associated factor 6. Eventually, phosphorylation of the inhibitor of NF-kappaB (IkappaB) by the IkappaB kinases releases NF-kappaB, which translocates to the nucleus and modulates gene expression. In this paper, we report that IRAK2 and MyD88, but not IRAK1, interact physically with Akt, as demonstrated by co-immunoprecipitation and pull-down experiments. Interestingly, the association of Akt with recombinant IRAK2 is decreased by stimulation with IL-1, and is favoured by pre-treatment with phosphatase. Likewise, Akt association with IRAK2 is increased considerably by overexpression of PTEN (phosphatase and tensin homologue deleted on chromosome 10), while it is completely abrogated by overexpression of phosphoinositide-dependent protein kinase 1. These data indicate that Akt takes part in the formation of the signalling complex that conveys the signal from the IL-1 receptors to NF-kappaB, a step that is much more membrane-proximal than was reported previously. We also demonstrate that Akt activity is necessary for IL-1-dependent NF-kappaB transactivation, since a kinase-defective mutant of Akt impairs IRAK2- and MyD88-dependent, but not IRAK1-dependent, NF-kappaB activity, as monitored by a gene reporter assay. Accordingly, IRAK2 failed to trigger inducible nitric oxide synthase and IL-1beta production in cells expressing dominant-negative Akt. However, NF-kappaB binding to DNA was not affected by inhibition of Akt, indicating that Akt regulates NF-kappaB at a level distinct from the dissociation of p65 from IkappaBalpha and its translocation to the nucleus, possibly involving phosphorylation of the p65 transactivation domain.

Interleukin-1 beta and interferon-gamma induce proliferation and apoptosis in cultured Schwann cells

This study reports that in Schwann cell tissue culture the administration of the two pro-inflammatory cytokines, interleukin-1 beta (IL-1 beta) and interferon-gamma (IFN-gamma), at different dosages, singly or in combination, can induce apoptosis and/or mitosis. Schwann cell apoptosis was maximal within 24 h of stimulation with 50 U/ml of IFN-gamma, while proliferation was at its peak within 24 h with 10 U/ml IL-1 beta, and both processes decreased progressively by 48 and 72 h. Moreover, the combination of the two cytokines did not show any synergistic effect. These data can be interpreted as a possible involvement of pro-inflammatory cytokines not only in myelin disruption but also in promoting remyelination.