Tailoring the Microarchitectures of 3D Printed Bone-like Scaffolds for Tissue Engineering Applications.

Material extrusion (MEX), commonly referred to as fused deposition modeling (FDM) or fused filament fabrication (FFF), is a versatile and cost-effective technique to fabricate suitable scaffolds for tissue engineering. Driven by a computer-aided design input, specific patterns can be easily collected in an extremely reproducible and repeatable process. Referring to possible skeletal affections, 3D-printed scaffolds can support tissue regeneration of large bone defects with complex geometries, an open major clinical challenge. In this study, polylactic acid scaffolds were printed resembling trabecular bone microarchitecture in order to deal with morphologically biomimetic features to potentially enhance the biological outcome. Three models with different pore sizes (i.e., 500, 600, and 700 µm) were prepared and evaluated by means of micro-computed tomography. The biological assessment was carried out seeding SAOS-2 cells, a bone-like cell model, on the scaffolds, which showed excellent biocompatibility, bioactivity, and osteoinductivity. The model with larger pores, characterized by improved osteoconductive properties and protein adsorption rate, was further investigated as a potential platform for bone-tissue engineering, evaluating the paracrine activity of human mesenchymal stem cells. The reported findings demonstrate that the designed microarchitecture, better mimicking the natural bone extracellular matrix, favors a greater bioactivity and can be thus regarded as an interesting option for bone-tissue engineering.

Severely Damaged Freeze-Injured Skeletal Muscle Reveals Functional Impairment, Inadequate Repair, and Opportunity for Human Stem Cell Application.

BACKGROUND: The regeneration of severe traumatic muscle injuries is an unsolved medical need that is relevant for civilian and military medicine. In this work, we produced a critically sized nonhealing muscle defect in a mouse model to investigate muscle degeneration/healing phases. MATERIALS AND METHODS: We caused a freeze injury (FI) in the biceps femoris of C57BL/6N mice. From day 1 to day 25 post-injury, we conducted histological/morphometric examinations, an analysis of the expression of genes involved in inflammation/regeneration, and an in vivo functional evaluation. RESULTS: We found that FI activates cytosolic DNA sensing and inflammatory responses. Persistent macrophage infiltration, the prolonged expression of eMHC, the presence of centrally nucleated myofibers, and the presence of PAX7+ satellite cells at late time points and with chronic physical impairment indicated inadequate repair. By looking at stem-cell-based therapeutic protocols of muscle repair, we investigated the crosstalk between M1-biased macrophages and human amniotic mesenchymal stem cells (hAMSCs) in vitro. We demonstrated their reciprocal paracrine effects where hAMSCs induced a shift of M1 macrophages into an anti-inflammatory phenotype, and M1 macrophages promoted an increase in the expression of hAMSC immunomodulatory factors. CONCLUSIONS: Our findings support the rationale for the future use of our injury model to exploit the full potential of in vivo hAMSC transplantation following severe traumatic injuries.

Biocompatibility assessment of sub-5 nm silica-coated superparamagnetic iron oxide nanoparticles in human stem cells and in mice for potential application in nanomedicine.

Ultrasmall superparamagnetic iron oxide nanoparticles with a size <5 nm are emerging nanomaterials for their excellent biocompatibility, chemical stability, and tunable surface modifications. The applications explored include dual-modal or multi-modal imaging, drug delivery, theranostics and, more recently, magnetic resonance angiography. Good biocompatibility and biosafety are regarded as the preliminary requirements for their biomedical applications and further exploration in this field is still required. We previously synthesized and characterized ultrafine (average core size of 3 nm) silica-coated superparamagnetic iron oxide fluorescent nanoparticles, named sub-5 SIO-Fl, uniform in size, shape, chemical properties and composition. The cellular uptake and in vitro biocompatibility of the as-synthesized nanoparticles were demonstrated in a human colon cancer cellular model. Here, we investigated the biocompatibility of sub-5 SIO-Fl nanoparticles in human Amniotic Mesenchymal Stromal/Stem Cells (hAMSCs). Kinetic analysis of cellular uptake showed a quick nanoparticle internalization in the first hour, increasing over time and after long exposure (48 h), the uptake rate gradually slowed down. We demonstrated that after internalization, sub-5 SIO-Fl nanoparticles neither affect hAMSC growth, viability, morphology, cytoskeletal organization, cell cycle progression, immunophenotype, and the expression of pro-angiogenic and immunoregulatory paracrine factors nor the osteogenic and myogenic differentiation markers. Furthermore, sub-5 SIO-Fl nanoparticles were intravenously injected into mice to investigate the in vivo biodistribution and toxicity profile for a time period of 7 weeks. Our findings showed an immediate transient accumulation of nanoparticles in the kidney, followed by the liver and lungs, where iron contents increased over a 7-week period. Histopathology, hematology, serum pro-inflammatory response, body weight and mortality studies demonstrated a short- and long-term biocompatibility and biosafety profile with no apparent acute and chronic toxicity caused by these nanoparticles in mice. Overall, these results suggest the feasibility of using sub-5 SIO-Fl nanoparticles as a promising agent for stem cell magnetic targeting as well as for diagnostic and therapeutic applications in oncology.

Combination of cord blood-derived human hepatic progenitors and hepatogenic factors strongly improves recovery after acute liver injury in mice through modulation of the Wnt/ß-catenin signaling.

Cell therapy represents a promising alternative strategy for end-stage liver disease, and hepatic progenitors are the best candidates. The possibility to maximize the paracrine effects of transplanted cells represents a great potential benefit for cell therapy success. We studied how cell type and microenvironment modulate the Wnt/ß-catenin signaling in vitro and in vivo. In vitro, the onset of hepatocyte commitment was characterized by the presence of nuclear truncated ß-catenin. In vivo, we analyzed the effect of human hepatic progenitors on damage recovery and functional regeneration in a mouse model of acute liver injury, either in combination or in absence of a selected mix of hepatogenic factors. Animals injected with human hepatic progenitors and hepatogenic factors showed improved engraftment triggering the Wnt/ß-catenin signaling cascade. Human hepatic progenitors expressing the human oval cell marker OV6 displayed a consistent colocalization with ß-catenin and colocalized with Wnt1 main ligand of the canonical pathway. Wnt5a, on the contrary, was expressed in distinct liver cell populations. Epithelial mesenchymal transition-related markers showed enhanced expression and wider distribution, and the hepato-mesenchymal population Thy1 + CK19- was also present. Control animals injected with hepatogenic factors alone exhibited higher ß-catenin, decreased Wnt5a levels, and persistent proliferation of the hepato-mesenchymal population. In conclusion, the combination of human hepatic progenitors with selected hepatogenic factors creates a positive synergy with local microenvironment, ameliorates cell engraftment, stimulates and accelerates regenerative process, and improves the rescue of hepatic function by modulating the Wnt/ßcatenin signaling and activating hepato-mesenchymal population.

Non-Ionizing Radiation for Cardiac Human Amniotic Mesenchymal Stromal Cell Commitment: A Physical Strategy in Regenerative Medicine.

Cell therapy is an innovative strategy for tissue repair, since adult stem cells could have limited regenerative ability as in the case of myocardial damage. This leads to a local contractile dysfunction due to scar formation. For these reasons, refining strategy approaches for "in vitro" stem cell commitment, preparatory to the "in vivo" stem cell differentiation, is imperative. In this work, we isolated and characterized at molecular and cellular level, human Amniotic Mesenchymal Stromal Cells (hAMSCs) and exposed them to a physical Extremely Low Frequency Electromagnetic Field (ELF-EMF) stimulus and to a chemical Nitric Oxide treatment. Physically exposed cells showed a decrease of cell proliferation and no change in metabolic activity, cell vitality and apoptotic rate. An increase in the mRNA expression of cardiac and angiogenic differentiation markers, confirmed at the translational level, was also highlighted in exposed cells. Our data, for the first time, provide evidence that physical ELF-EMF stimulus (7 Hz, 2.5 µT), similarly to the chemical treatment, is able to trigger hAMSC cardiac commitment. More importantly, we also observed that only the physical stimulus is able to induce both types of commitments contemporarily (cardiac and angiogenic), suggesting its potential use to obtain a better regenerative response in cell-therapy protocols.

Placenta Derived Mesenchymal Stem Cells Hosted on RKKP Glass-Ceramic: A Tissue Engineering Strategy for Bone Regenerative Medicine Applications.

In tissue engineering protocols, the survival of transplanted stem cells is a limiting factor that could be overcome using a cell delivery matrix able to support cell proliferation and differentiation. With this aim, we studied the cell-friendly and biocompatible behavior of RKKP glass-ceramic coated Titanium (Ti) surface seeded with human amniotic mesenchymal stromal cells (hAMSCs) from placenta. The sol-gel synthesis procedure was used to prepare the RKKP glass-ceramic material, which was then deposited onto the Ti surface by Pulsed Laser Deposition method. The cell metabolic activity and proliferation rate, the cytoskeletal actin organization, and the cell cycle phase distribution in hAMSCs seeded on the RKKP coated Ti surface revealed no significant differences when compared to the cells grown on the treated plastic Petri dish. The health of of hAMSCs was also analysed studying the mRNA expressions of MSC key genes and the osteogenic commitment capability using qRT-PCR analysis which resulted in being unchanged in both substrates. In this study, the combination of the hAMSCs' properties together with the bioactive characteristics of RKKP glass-ceramics was investigated and the results obtained indicate its possible use as a new and interesting cell delivery system for bone tissue engineering and regenerative medicine applications.

C-MYC modulation induces responsiveness to paclitaxel in adrenocortical cancer cell lines.

C-MYC is overexpressed in many types of cancer linked to poor prognosis. We examined the c-Myc protein expression in adrenocortical cancer (ACC) cells to investigate the role of this protein in the neoplasm, its involvement in chemotherapy and finally to determine whether c-Myc could be considered a prognostic factor in patients with ACC. H295R and SW13 cell lines were treated with paclitaxel. c-Myc overexpressing cell clones were achieved by transfecting the H295R cell line with the pcDNA3-hMYC plasmid expressing the full-lengh C-MYC coding sequence. The SW13 cell line was transfected with siRNA oligonucleotides for C-MYC. Cell cycle analysis was evaluated by flow cytometry. c-Myc, cyclin B1 and pro caspase expression levels were evaluated by western blot analysis. We found that expression of c-Myc was highly expressed in the SW13 cells, whereas the protein was undetectable in the H295R cells. Different doses of paclitaxel were required in the two ACC cell line to induce a block in the G2 phase, characterized by increased cyclin B1 levels and to induce apoptosis by pro-caspase-3 activation. Interestingly, the silencing of C-MYC mRNA prevented paclitaxel induced apoptosis in SW13 cells, whereas in the H295R cells the overexpression of C-MYC rendered the cells more prone to growth inhibition after paclitaxel exposure. The present study directly demonstrates that C-MYC plays a central role in controlling proliferation in ACC cells after paclitaxel treatment and that c-Myc could be considered as a marker for predicting response to chemotherapeutic agents in ACC cell lines.

Nonpulsed sinusoidal electromagnetic fields as a noninvasive strategy in bone repair: the effect on human mesenchymal stem cell osteogenic differentiation.

In vivo control of osteoblast differentiation is an important process needed to maintain the continuous supply of mature osteoblast cells for growth, repair, and remodeling of bones. The regulation of this process has also an important and significant impact on the clinical strategies and future applications of cell therapy. In this article, we studied the effect of nonpulsed sinusoidal electromagnetic field radiation tuned at calcium-ion cyclotron frequency of 50 Hz exposure treatment for bone differentiation of human mesenchymal stem cells (hMSCs) alone or in synergy with dexamethasone, their canonical chemical differentiation agent. Five days of continuous exposure to calcium-ion cyclotron resonance affect hMSC proliferation, morphology, and cytoskeletal actin reorganization. By quantitative real-time polymerase chain reaction, we also observed an increase of osteoblast differentiation marker expression such as Runx2, alkaline phosphatase (ALP), osteocalcin (OC), and osteopontin (OPN) together with the osteoprotegerin mRNA modulation. Moreover, in these cells, the increase of the protein expression of OPN and ALP was also demonstrated. These results demonstrate bone commitment of hMSCs through a noninvasive and biocompatible differentiating physical agent treatment and highlight possible applications in new regenerative medicine protocols.

p53 Stabilization induces cell growth inhibition and affects IGF2 pathway in response to radiotherapy in adrenocortical cancer cells.

Adrenocortical carcinoma (ACC) is a very rare endocrine tumour, with variable prognosis, depending on tumour stage and time of diagnosis. However, it is generally fatal, with an overall survival of 5 years from detection. Radiotherapy usefulness for ACC treatment has been widely debated and seems to be dependent on molecular alterations, which in turn lead to increased radio-resistance. Many studies have shown that p53 loss is an important risk factor for malignant adrenocortical tumour onset and it has been reported that somatic mutations in TP53 gene occur in 27 to 70% of adult sporadic ACCs. In this study, we investigated the role of somatic mutations of the TP53 gene in response to ionizing radiation (IR). We studied the status of p53 in two adrenocortical cell lines, H295R and SW-13, harbouring non-functioning forms of this protein, owing to the lack of exons 8 and 9 and a point mutation in exon 6, respectively. Moreover, these cell lines show high levels of p-Akt and IGF2, especially H295R. We noticed that restoration of p53 activity led to inhibition of growth after transient transfection of cells with wild type p53. Evaluation of their response to IR in terms of cell proliferation and viability was determined by means of cell count and TUNEL assay.(wt)p53 over-expression also increased cell death by apoptosis following radiation in both cell lines. Moreover, RT-PCR and Western blotting analysis of some p53 target genes, such as BCL2, IGF2 and Akt demonstrated that p53 activation following IR led to a decrease in IGF2 expression. This was associated with a reduction in the active form of Akt. Taken together, these results highlight the role of p53 in response to radiation of ACC cell lines, suggesting its importance as a predictive factor for radiotherapy in malignant adrenocortical tumours cases.

A combined synthetic-fibrin scaffold supports growth and cardiomyogenic commitment of human placental derived stem cells.

AIMS: A potential therapy for myocardial infarction is to deliver isolated stem cells to the infarcted site. A key issue with this therapy is to have at one's disposal a suitable cell delivery system which, besides being able to support cell proliferation and differentiation, may also provide handling and elastic properties which do not affect cardiac contractile function. In this study an elastic scaffold, obtained combining a poly(ether)urethane-polydimethylsiloxane (PEtU-PDMS) semi-interpenetrating polymeric network (s-IPN) with fibrin, was used as a substrate for in vitro studies of human amniotic mesenchymal stromal cells (hAMSC) growth and differentiation. METHODOLOGY/PRINCIPAL FINDINGS: After hAMSC seeding on the fibrin side of the scaffold, cell metabolic activity and proliferation were evaluated by WST-1 and bromodeoxyuridine assays. Morphological changes and mRNAs expression for cardiac differentiation markers in the hAMSCs were examined using immunofluorescence and RT-PCR analysis. The beginning of cardiomyogenic commitment of hAMSCs grown on the scaffold was induced, for the first time in this cell population, by a nitric oxide (NO) treatment. Following NO treatment hAMSCs show morphological changes, an increase of the messenger cardiac differentiation markers [troponin I (TnI) and NK2 transcription factor related locus 5 (Nkx2.5)] and a modulation of the endothelial markers [vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR)]. CONCLUSIONS/SIGNIFICANCE: The results of this study suggest that the s-IPN PEtU-PDMS/fibrin combined scaffold allows a better proliferation and metabolic activity of hAMSCs cultured up to 14 days, compared to the ones grown on plastic dishes. In addition, the combined scaffold sustains the beginning of hAMSCs differentiation process towards a cardiomyogenic lineage.

Rosiglitazone induces autophagy in H295R and cell cycle deregulation in SW13 adrenocortical cancer cells.

Thiazolidinediones, specific peroxisome proliferator-activated receptor-γ (PPAR-γ) ligands, used in type-2 diabetes therapy, show favourable effects in several cancer cells. In this study we demonstrate that the growth of H295R and SW13 adrenocortical cancer cells is inhibited by rosiglitazone, a thiazolidinediones member, even though the mechanisms underlying this effect appeared to be cell-specific. Treatment with GW9662, a selective PPAR-γ-inhibitor, showed that rosiglitazone acts through both PPAR-γ-dependent and -independent mechanisms in H295R, while in SW13 cells the effect seems to be independent of PPAR-γ. H295R cells treated with rosiglitazone undergo an autophagic process, leading to morphological changes detectable by electron microscopy and an increased expression of specific proteins such as AMPKα and beclin-1. The autophagy seems to be independent of PPAR-γ activation and could be related to an increase in oxidative stress mediated by reactive oxygen species production with the disruption of the mitochondrial membrane potential, triggered by rosiglitazone. In SW13 cells, flow cytometry analysis showed an arrest in the G0/G1 phase of the cell cycle with a decrease of cyclin E and cdk2 activity, following the administration of rosiglitazone. Our data show the potential role of rosiglitazone in the therapeutic approach to adrenocortical carcinoma and indicate the molecular mechanisms at the base of its antiproliferative effects, which appear to be manifold and cell-specific in adrenocortical cancer lines.

Temozolomide induced c-Myc-mediated apoptosis via Akt signalling in MGMT expressing glioblastoma cells.

PURPOSE: We investigated the molecular mechanisms underlying the cytotoxic effect of Temozolomide (TMZ) in both O(6)-methylguanine-DNA methyl transferase (MGMT) depleted as well as undepleted glioblastoma cell lines. Since TMZ is used in clinics in combination with radiotherapy, we also studied the effects of TMZ in combination with ionising radiation (IR). METHODS: Cell colony-forming ability was measured using a clonogenic assay. Cell cycle analysis and apoptosis were evaluated by Flow Cytometry (FCM). Proteins involved in cell cycle control were detected by Western blot and co-immunoprecipitation assays. RESULTS: Our data showed that TMZ, independent of MGMT expression, inhibited glioblastoma cell growth via an irreversible G(2) block in MGMT depleted cells or the induction of apoptosis in MGMT normal expressing cells. When TMZ was administered in combination with IR, apoptosis was greater than observed with either agent separately. This TMZ-induced apoptosis in the MGMT expressing cells occurred through Akt/Glycogen-Synthase-Kinase-3ß (GSK3ß) signalling and was mediated by Myelocytomatosis (c-Myc) oncoprotein. Indeed, TMZ phosphorylated/activated Akt led to phosphorylation/inactivation of GSK3ß which resulted in the stabilisation of c-Myc protein and subsequent modulation of the c-Myc target genes involved in the apoptotic processes. CONCLUSION: C-Myc expression could be considered a good indicator of TMZ effectiveness.

Cord blood CD133 cells define an OV6-positive population that can be differentiated in vitro into engraftable bipotent hepatic progenitors.

Cell therapy represents the most promising alternative strategy for end-stage liver diseases and hepatic progenitors are the best candidates. We have identified a reservoir of immature hepatic precursors within human cord blood, which can derive engraftable bipotent progenitors. We isolated a stem cell subset CD133+/CD34+/OV6(low) expressing a surface-marker profile consistent with that of fetal liver cells. Upon induction of hepatic commitment by a medium containing cytokines and factors involved in vivo oval-cell activation, a heterogeneous cell population displaying characteristics of functional oval-cell-like bipotent hepatic progenitors was obtained. The cells expressed markers of hepatocytes and cholangiocytes and were highly enriched in OV6, c-Met, c-Kit, and Thy-1. They also displayed liver functional activity as glycogen storage, urea production, albumin secretion, and inducible CyP2B6 activity. When injected into liver-damaged severe-combined immunodeficient mice, induced bipotent hepatic progenitors appropriately engrafted livers of recipient animals, where they formed clusters of human-derived cells expressing human leucocyte antigen-class I, Hep-Par1, and OV6 antigens. Human-specific albumin, alpha-fetoprotein, and cytokeratin 19 were also expressed. In transplanted animals, AST serum levels showed a significative reduction with regard to controls. This human model for in vitro progenitor-cell activation may provide a powerful tool for elucidating the pathways and synergies that regulate this complex process and can represent a valuable source, exploitable for liver cell-based therapies and regenerative medicine.

Alteration of local microflora and α-defensins hyper-production in colonic adenoma mucosa.

BACKGROUND AND AIM: Gut flora/host interactions are fundamental for the maintenance of homeostasis. Evidence of possible regulatory effect of commensal bacteria on proliferative disorders of the colon is mounting. In this study, we explored the hypothesis that precancerous lesions, such as adenomas, present alteration of the local microflora and lead to an overproduction of antibacterial molecules of the innate immunity, namely α-defensins. Thus, the host-bacteria misbalance could represent a potential procarcinogenic factor. METHODS: Biopsies from adenomatous polyps and normal mucosa, in the rectum-sigmoid colon, were collected from 51 patients. Concentration of mucosal bacteria was evaluated by real-time polymerase chain reaction after extraction of total DNA. Total RNA was also extracted, and the defensin α-1, defensin-5, and defensin-6 gene expressions were evaluated by real-time polymerase chain reaction. Immunohistochemical study has been carried out to evaluate protein production and location. Antibacterial activity of adenomatous polyps mucosa was evaluated in vitro. RESULTS: Biopsies from adenomatous polyps had a significant relative reduction of mucosa adherent bacteria compared with normal tissue (20-fold relative reduction, P<0.05). Concomitantly, α-defensin expression and production were significantly increased in adenomas. Adenoma mucosa showed increased antibacterial activity in vitro compared with normal mucosa. CONCLUSIONS: Microflora dysbiosis occurs at the mucosal surface in colonic adenomas, and may represent a potential factor for dysplastic cell proliferation. Further studies are needed to confirm and define the role of this mechanism in colon carcinogenesis and the potential applications in the clinical setting.

Mitotane sensitizes adrenocortical cancer cells to ionizing radiations by involvement of the cyclin B1/CDK complex in G2 arrest and mismatch repair enzymes modulation.

Mitotane inhibits steroid synthesis by an action on steroidogenic enzymes, as 11beta-hydroxylase and cholesterol side chain cleavage. It also has a cytotoxic effect on the adrenocortical cells and represents a primary drug used in the adrenocortical carcinoma (ACC). H295R and SW13 cell lines were treated with mitotane 10(-5) M and ionizing radiations (IR) in combination therapy, inducing an irreversible inhibition of cell growth in both adrenocortical cancer cells. As shown in a previous report, mitotane/IR combination treatment induced a cell accumulation in the G2 phase. Here, we report the radiosensitizing properties of mitotane in two different ACC cell lines. The drug reveals the effectiveness to enhance the cytotoxic effects of IR by attenuating DNA repair and interfering on the activation of mitosis promoting factor (MPF), mainly regulated by the degradation of cyclin B1 in the mitotic process. These events may explain the inappropriate activation of cdc2, implicated in G2/M phase arrest and probably induced by the mitotane and IR in the combined treatment. Indeed, treatment with purvalanol, a cdc2-inhibitor prevents cell cycle arrest, triggering the G2/M transition. The observation that mitotane and IR in combination treatment amplifies the activation level of cyclin B/cdc2 complexes contributing to cell cycle arrest, suggests that the MPF could function as a master signal for controlling the temporal order of different mitotic events. Moreover, we report that mitotane interferes in modulation of mismatch repair (MMR) enzymes, revealing radiosensitizing drug ability.

Liver stem cells and possible clinical applications.

The discovery of several sources of hepatic progenitors in extra-hepatic organs and tissues, both in animal models and in humans, supports opportunities to isolate, grow and expand them in vitro. Microenvironment factors involved in regulating proliferation and commitment of liver cell precursors have been identified and better characterization of liver stem cell pathobiology would greatly improve the understanding of liver differentiation/ regeneration processes, especially those leading to hepatocarcinogenesis. The goal of these researches has been to discover the most available, suitable and easy-to-use pluripotent stem cells (PSC) sources for cell-based therapies in genetic and acquired liver diseases, therapies which to date have required liver transplantation. This report reviews the efforts, so far, to either investigate the presence of PSC in hepatic and extra-hepatic districts or evaluate their capacity to differentiate in vitro and to restore in vivo liver function.

Low correspondence between K-ras mutations in pancreatic cancer tissue and detection of K-ras mutations in circulating DNA.

OBJECTIVE: K-ras is the most frequently mutated gene in pancreatic cancer; reported rates range from 70% to 90%. The aim of this study was to evaluate the correspondence between K-ras mutations in pancreatic cancer tissue and in circulating DNA and the value of K-ras mutations as serological marker. METHODS: The research was conducted in 30 patients with pancreatic cancer in whom both plasma and neoplastic tissues were available. Such research was extended to circulating DNA isolated from 40 patients with chronic pancreatitis. Mutations in codon 12 were examined by mutant allele-specific amplification method and by direct sequencing. Serum values of routinely used tumor markers such as carbohydrate antigen (Ca) 19.9, carcinoembryonic antigen, Ca 50, and Ca 242 have been tested in all the patients enrolled in this study. RESULTS: K-ras mutations were detected in 70% of neoplastic tissue samples, but no mutated DNA resulted in circulating DNA samples. The 60% of patients with tissue K-ras mutation showed elevation of some tumor markers among Ca 19.9, carcinoembryonic antigen, Ca 50, and Ca 242. As a whole, these last showed low sensitivity (20%-56.67%) and specificity (56.67%-77.5%) when compared with chronic pancreatitis. CONCLUSION: Over the years, there has been no change in the direction of an earlier diagnosis by serological markers, and also, these data indicate that K-ras mutation in serum is an unsatisfactory method for the detection in patients with pancreatic cancer as well as in patients with high risk of progression toward neoplastic pancreatic disease.

Fractionated ionizing radiation exposure induces apoptosis through caspase-3 activation and reactive oxygen species generation.

BACKGROUND: Radiation therapy (RT) is a well established therapeutic modality for the treatment of solid tumors. In particular, post-operative RT is considered the standard treatment adjuvant to surgery since its ability to prolong median survival of patients with malignant astrocytoma has been shown; nevertheless the ionizing radiation (IR) treatment fails in a considerable number of astrocytoma patients. MATERIALS AND METHODS: Using an ADF human astrocytoma cell line the molecular mechanisms involved in the DNA damage induced by fractionated irradiation (FIR) and single IR treatment have been investigated. RESULTS: FIR and single IR treatment inhibited the growth of the ADF human astrocytoma cell line. FACS analysis revealed that FIR treatment, but not single IR treatment, induced growth inhibition associated with the induction of apoptosis. Apoptosis was related to caspase-3 activation and reactive oxygen species (ROS) generation. ROS formation depends on the up-regulation of the cytochrome P450 enzyme gene. On the contrary, 12.5 Gy induced necrotic cell death up-regulating the HSPD1, HSPCB, HSPCA and HSPB1 genes. CONCLUSION: FIR treatment induced cell death through caspase-3 and ROS-mediated apoptosis.

Myc down-regulation sensitizes melanoma cells to radiotherapy by inhibiting MLH1 and MSH2 mismatch repair proteins.

PURPOSE: Melanoma patients have a very poor prognosis with a response rate of <1% due to advanced diagnosis. This type of tumor is particularly resistant to conventional chemotherapy and radiotherapy, and the surgery remains the principal treatment for patients with localized melanoma. For this reason, there is particular interest in the melanoma biological therapy. EXPERIMENTAL DESIGN: Using two p53 mutant melanoma models stably expressing an inducible c-myc antisense RNA, we have investigated whether Myc protein down-regulation could render melanoma cells more susceptible to radiotherapy, reestablishing apoptotic p53-independent pathway. In addition to address the role of p53 in the activation of apoptosis, we studied the effect of Myc down-regulation on radiotherapy sensitivity also in a p53 wild-type melanoma cell line. RESULTS: Myc down-regulation is able per se to induce apoptosis in a fraction of the cell population (approximately 40% at 72 hours) and in combination with gamma radiation efficiently enhances the death process. In fact, approximately 80% of apoptotic cells are evident in Myc down-regulated cells exposed to gamma radiation for 72 hours compared with approximately 13% observed after only gamma radiation treatment. Consistent with the enhanced apoptosis is the inhibition of the MLH1 and MSH2 mismatch repair proteins, which, preventing the correction of ionizing radiation mismatches occurring during DNA replication, renders the cells more prone to radiation-induced apoptosis. CONCLUSIONS: Data herein reported show that Myc down-regulation lowers the apoptotic threshold in melanoma cells by inhibiting MLH1 and MSH2 proteins, thus increasing cell sensitivity to gamma radiation in a p53-independent fashion. Our results indicate the basis for developing new antitumoral therapeutic strategy, improving the management of melanoma patients.

p53 polymorphism at codon 72 is not a risk factor for cervical carcinogenesis in central Italy.

Recently Storey et al. showed that p53 polymorphism at codon 72 was related to cervical cancer. This polymorphism encodes either arginine (p53Arg) or proline (p53Pro). p53Arg was found to be more susceptible than p53Pro to E6-mediated degradation. Many studies were performed but conclusions are controversial. In this paper, we report our results from 80 women of central Italy, 30 patients showing High-grade Cervical Intraepithelial Neoplasia or squamous cell carcinoma (SCC) and 50 healthy women of the same age. The polymorphism was examined using the Storey's procedure, a molecular method, from formalin-fixed, paraffin-embedded biopsies (patients) and from cytological oral-samples (controls). The distribution of the genotypes among the cases was 27% heterozygous, 27% p53Pro-homozygous and 46% p53Arg-homozygous, while among the controls it was 52%, 2% and 46%, respectively. There was not an increased risk of SCC associated with p53Arg-homozygous; indeed there is a tendency for the contrary (odds ratio, 0.06; 99.4% confidence interval, 0.006-0.63; p = 0.019). Considering: 1) the biological characteristics of p53Pro in vitro; 2) the DNA quality, from formalin-fixed tissue, of our patients; and 3) the small number of samples performed in our study, we can only confirm that p53Pro is not a risk factor in vivo for cervical carcinogenesis in central Italy.