[Evaluation in vitro of the cardiotoxic effects of 5-fluorouracil for the prevention of cardiovascular damage in health workers occupationally exposed]. / Valutazione in vitro degli effetti cardiotossici da 5-fluorouracile per la prevenzione dei danni cardiovascolari negli operatori sanitari professionalmente esposti.

The occupational exposure to antineoplastic drugs in health care workers determines a risk of absorption through inhalation of vapors or skin contact with drops. Even if many data confirm the cardiotoxicity of anthracyclines, is not clear the evidence of cytotoxicity of 5-Fluorouracil, thoug in a percent of patients receiving this chemotherapy, there is the presence of heart pain, aspecific ECG disorders and induction of coronary disease. This experimental study wants to analyze on the H9c2 cardiomyocyte cell model the effects of 5-Fluorouracil, commonly used in hospital realities of the South Italy, for the prevention of the possible cardiovascular damage in workers occupationally exposed.

Bovine serum amine oxidase and spm potentiate docetaxel and interferon-alpha effects in inducing apoptosis on human cancer cells through the generation of oxidative stress.

It was previously demonstrated that bovine serum amine-oxidase (BSAO) and SPM (SPM) addition to cancer cells induces cell growth inhibition and over-run the multi-drug resistance (MDR) phenotype through the oxidative stress caused by polyamine metabolites. In this study, it is reported that BSAO/SPM enzymatic system antagonizes the survival pathway induced by either docetaxel (DTX) or interferon alpha (IFNalpha) in human epidermoid cancer KB cells. The combination of BSAO/SPM with either DTX or IFNalpha had a synergistic effect on cell growth inhibition through apoptosis in both human epidermoid KB and breast cancer MCF-7 cell lines. The effects of the BSAO/SPM-DTX combination on apoptosis were caspase 3 and 9-dependent and were paralleled by the enhancement of intracellular O(2-), nitric oxide levels and of lipo-oxidation. The scavenger moiety N-acetyl-cysteine antagonized the effects on apoptosis and cell growth inhibition induced by the combination suggesting a role of the oxidative products of SPM. These effects occurred together with a decrease of the physiological scavenger MnSOD and an increase of both p38 kinase activity and DNA damage. The results suggest that DTX and IFNalpha could sensitize tumour cells to the oxidative stress and apoptosis induced by BSAO/SPM through the induction of a survival ras-dependent pathway and the consequent elevation of the intracellular polyamine pool. These data allow the design of new therapeutic strategy based on the use of this combination in human neoplasms.

The 1,4 benzoquinone-featured 5-lipoxygenase inhibitor RF-Id induces apoptotic death through downregulation of IAPs in human glioblastoma cells.

BACKGROUND: Embelin is a potent dual inhibitor of 5-lipoxigenase (5-LOX) and microsomal prostaglandin E2 synthase (mPGES)-1 that suppresses proliferation of human glioma cells and induces apoptosis by inhibiting XIAP and NF-κB signaling pathway. Synthetic structural modification yielded the derivative 3-((decahydronaphthalen-6-yl)methyl)-2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (RF-Id), an embelin constrained analogue, with improved efficiency against 5-LOX in human neutrophils and anti-inflammatory activity in vivo. Taking into account that lipoxygenase (LOX) metabolites, from arachidonic acid and linoleic acid, have been implicated in tumor progression, here, we determined whether RF-Id was able to hinder glioblastoma (GBM) cancer cell growth and the related mechanisms. METHODS: U87MG and LN229 cells were plated in 96-wells and treated with increasing concentrations of RF-Id. Cell viability was evaluated by MTT assay. The effects of the compounds on cell cycle, apoptosis, oxidative stress and autophagy were assessed by flow cytometry (FACS). The mode of action was confirmed by Taqman apoptosis array and evaluating caspase cascade and NFκB pathway by western blotting technique. RESULTS: Here, we found that RF-Id induced a stronger inhibition of GBM cell growth than treatment with embelin. Flow cytometry analysis showed that RF-Id induced about 30 % apoptosis and a slight increase of autophagy after 72 h on U87-MG cells. Moreover, the compound induced an increase in the percentage of cells in G2 and S phase that was paralleled by an increase of p21 and p27 expression but no significant changes of the mitochondrial membrane potential; array analysis showed a significant upregulation of CASP8 and a downregulation of IAP family and NFκB genes in cells treated with RF-Id. RF-Id induced a significant cleavage of caspases 8, 9, 3 and 7, blocked c-IAP2/XIAP interaction by inducing XIAP degradation and inhibited NFκB pathway. CONCLUSIONS: RF-Id induced a caspase-dependent apoptosis in GBM cells by inhibiting IAP family proteins and NFκB pathway and represents a promising lead compound for designing a new class of anti-cancer drugs with multiple targets.

Transferrin-Targeted Nanoparticles Containing Zoledronic Acid as a Potential Tool to Inhibit Glioblastoma Growth.

The treatment of glioblastoma (GBM) is a challenge for the biomedical research since cures remain elusive. Its current therapy, consisted on surgery, radiotherapy, and concomitant chemotherapy with temozolomide (TMZ), is often uneffective. Here, we proposed the use of zoledronic acid (ZOL) as a potential agent for the treatment of GBM. Our group previously developed self-assembling nanoparticles, also named PLCaPZ NPs, to use ZOL in the treatment of prostate cancer. Here, we updated the previously developed nanoparticles (NPs) by designing transferrin (Tf)-targeted self-assembling NPs, also named Tf-PLCaPZ NPs, to use ZOL in the treatment of brain tumors, e.g., GBM. The efficacy of Tf-PLCaPZ NPs was evaluated in different GBM cell lines and in an animal model of GBM, in comparison with PLCaPZ NPs and free ZOL. Tf-PLCaPZ NPs were characterized by a narrow size distribution and a high incorporation efficiency of ZOL. Moreover, the presence of Tf significantly reduced the hemolytic activity of the formulation. In vitro, in LN229 cells, a significant uptake and cell growth inhibition after treatment with Tf-PLCaPZ NPs was achieved. Moreover, the sequential therapy of TMZ and Tf-PLCaPZ NPs lead to a superior therapeutic activity compared to their single administration. The results obtained in mice xenografted with U373MG, revealed a significant anticancer activity of Tf-PLCaPZ NPs, while the tumors remained unaffected with free TMZ. These promising results introduce a novel type of easy-to-obtain NPs for the delivery of ZOL in the treatment of GBM tumors.

Antagonistic effects of chloroquine on autophagy occurrence potentiate the anticancer effects of everolimus on renal cancer cells.

Renal cell carcinoma is an aggressive disease often asymptomatic and weakly chemo-radiosensitive. Currently, new biologic drugs are used among which everolimus, an mTOR inhibitor, that has been approved for second-line therapy. Since mTOR is involved in the control of autophagy, its antitumor capacity is often limited. In this view, chloroquine, a 4-alkylamino substituted quinoline family member, is an autophagy inhibitor that blocks the fusion of autophagosomes and lysosomes. In the present study, we evaluated the effects of everolimus alone or in combination with chloroquine on renal cancer cell viability and verified possible synergism. Our results demonstrate that renal cancer cells are differently sensitive to everolimus and chloroquine and the pharmacological combination everolimus/chloroquine was strongly synergistic inducing cell viability inhibition. In details, the pharmacological synergism occurs when chloroquine is administered before everolimus. In addition, we found a flow autophagic block and shift of death mechanisms to apoptosis. This event was associated with decrease of Beclin-1/Bcl(-)2 complex and parallel reduction of anti-apoptotic protein Bcl(-)2 in combined treatment. At last, we found that the enhancement of apoptosis induced by drug combination occurs through the intrinsic mitochondrial apoptotic pathway activation, while the extrinsic pathway is involved only partly following its activation by chloroquine. These results provide the basis for new therapeutic strategies for the treatment of renal cell carcinoma after appropriate clinical trial.

Dicrocoelium dendriticum induces autophagic vacuoles accumulation in human hepatocarcinoma cells.

The relationship between Dicrocoelium dendriticum and cancer has been poorly investigated so far, but a large amount of findings suggest that other trematodes can favour cancer in both animals and humans. In this study, the effects of D. dendriticum on cell proliferation, cell death mechanisms and oxidative stress induction were evaluated in hepatocellular carcinoma (HCC) cell lines (HepG2 and HuH7). Results showed that short time exposure to low concentrations of somatic antigens from D. dendriticum caused slight proliferation in both HepG2 and HuH7 cells while high concentrations and long exposure time to extracts from D. dendriticum caused a significant growth inhibition. This effect was, however, not paralleled by apoptosis but it occurred with an about 40% increase of the formation of autophagic vacuoles. In the same experimental conditions, a strong oxidative stress was recorded with an about 100% increase of the intracellular O(2-). These data suggest the occurrence of an escape anti-apoptotic mechanism in HCC cells. In conclusion, these results suggest a role for D. dendriticum in the chronic oxidative stress and in the regulation of transformation processes in HCC warranting additional investigations in this specific area of research.

[Positive selection of hematopoietic CD 34 stem cells for autograft]. / Sélection positive de cellules souches hématopoïétiques CD 34 pour autogreffe.

The CD 34 antigen is a glycoprotein found on the surface of hematopoietic stem cells and early committed progenitors. The CE 34 stem cells from 14 samples of bone marrow, cord blood or leucapheresis were isolated using a positive selection procedure involving an anti CD 34 biotinylated monoclonal antibody and an avidin immunoabsorption device. Results showed that in 60 percent of samples, the positively-selected fractions contained more than 70 percent CD 34 cells. Concentration in CFU-GM and BFU-E progenitors increased 15 and 26 fold respectively in the CE 34 enriched samples. Long-term culture of two samples demonstrated that nearly all of the most immature progenitors were recovered in the procedure. These preliminary results showed that the positive selection technique of CD 34 hematopoietic stem cells is now available for use in autologous or allogeneic hematopoietic stem cell transplantation.

Raf kinases mediate the phosphorylation of eukaryotic translation elongation factor 1A and regulate its stability in eukaryotic cells.

We identified eukaryotic translation elongation factor 1A (eEF1A) Raf-mediated phosphorylation sites and defined their role in the regulation of eEF1A half-life and of apoptosis of human cancer cells. Mass spectrometry identified in vitro S21 and T88 as phosphorylation sites mediated by B-Raf but not C-Raf on eEF1A1 whereas S21 was phosphorylated on eEF1A2 by both B- and C-Raf. Interestingly, S21 belongs to the first eEF1A GTP/GDP-binding consensus sequence. Phosphorylation of S21 was strongly enhanced when both eEF1A isoforms were preincubated prior the assay with C-Raf, suggesting that the eEF1A isoforms can heterodimerize thus increasing the accessibility of S21 to the phosphate. Overexpression of eEF1A1 in COS 7 cells confirmed the phosphorylation of T88 also in vivo. Compared with wt, in COS 7 cells overexpressed phosphodeficient (A) and phospho-mimicking (D) mutants of eEF1A1 (S21A/D and T88A/D) and of eEF1A2 (S21A/D), resulted less stable and more rapidly proteasome degraded. Transfection of S21 A/D eEF1A mutants in H1355 cells increased apoptosis in comparison with the wt isoforms. It indicates that the blockage of S21 interferes with or even supports C-Raf induced apoptosis rather than cell survival. Raf-mediated regulation of this site could be a crucial mechanism involved in the functional switching of eEF1A between its role in protein biosynthesis and its participation in other cellular processes.

Self-assembly nanoparticles for the delivery of bisphosphonates into tumors.

Bisphosphonates (BPs) are molecules able to induce apoptosis in several cancer cell lines. However, their short half-life and the rapid uptake and accumulation within bone, limit its use as antitumor agent for extra-skeletal malignancies. Here we proposed a new delivery system to avoid BP accumulation into the bone, thus improving extra-skeletal bioavailability. In this work, we used the zoledronic acid (ZOL), a third generation bisphosphonate, able to induce apoptosis at micromolar concentration. We developed ZOL-containing self-assembly PEGylated nanoparticles (NPs) based on ZOL complexes with calcium phosphate NPs (CaPZ NPs) and cationic liposomes. PEGylation was achieved by two different strategies. CaPZ NPs were covered with PEGylated liposomes (pre-PLCaPZ NPs); alternatively, CaPZ NPs were previously mixed with cationic liposomes and then PEGylated by post-insertion method (post-PLCaPZ NPs). The NPs were fully characterized in terms of mean diameter and size distribution, morphology, ZOL loading, antiproliferative effect on different cell lines. Pre-PLCaPZ NPs showed the best technological characteristics, with a narrow size distribution and a high ZOL loading. Moreover, on different cancer cell lines, these NPs enhanced the antiproliferative effect of ZOL. Finally, in an animal model of prostate cancer, a significant reduction of tumor growth was achieved with pre-PLCaPZ NPs, while the tumor was unaffected by ZOL in solution.

Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism.

Gemcitabine (GEM, 2',2'-difluorodeoxycytidine) is currently used in advanced pancreatic adenocarcinoma, with a response rate of < 20%. The purpose of our work was to improve GEM activity by addition of cannabinoids. Here, we show that GEM induces both cannabinoid receptor-1 (CB1) and cannabinoid receptor-2 (CB2) receptors by an NF-κB-dependent mechanism and that its association with cannabinoids synergistically inhibits pancreatic adenocarcinoma cell growth and increases reactive oxygen species (ROS) induced by single treatments. The antiproliferative synergism is prevented by the radical scavenger N-acetyl-L-cysteine and by the specific NF-κB inhibitor BAY 11-7085, demonstrating that the induction of ROS by GEM/cannabinoids and of NF-κB by GEM is required for this effect. In addition, we report that neither apoptotic nor cytostatic mechanisms are responsible for the synergistic cell growth inhibition, which is strictly associated with the enhancement of endoplasmic reticulum stress and autophagic cell death. Noteworthy, the antiproliferative synergism is stronger in GEM-resistant pancreatic cancer cell lines compared with GEM-sensitive pancreatic cancer cell lines. The combined treatment strongly inhibits growth of human pancreatic tumor cells xenografted in nude mice without apparent toxic effects. These findings support a key role of the ROS-dependent activation of an autophagic program in the synergistic growth inhibition induced by GEM/cannabinoid combination in human pancreatic cancer cells.

Emerging strategies to strengthen the anti-tumour activity of type I interferons: overcoming survival pathways.

Interferon-a (IFN-a) is currently the most used cytokine in the treatment of cancer. However, the potential anti-tumour activity of IFN-a is limited by the activation of tumour resistance mechanisms. In this regard, we have shown that IFN-a, at growth inhibitory concentrations, enhances the EGF-dependent Ras-->Erk signalling and decreases the adenylate cyclase/cAMP pathway activity in cancer cells; both effects represent escape mechanisms to the growth inhibition and apoptosis induced by IFN-a. The selective targeting of these survival pathways might enhance the antitumor activity of IFN-ain cancer cells, as shown by: i) the combination of selective EGF receptor tyrosine kinase inhibitor (gefitinib) and IFN-a having cooperative anti-tumour effects; ii) the farnesyl-transferase inhibitor R115777 strongly potentiating the anti-tumour activity of IFN-a both in vitro and in vivo through the inhibition of different escape mechanisms that are dependent on isoprenylation of intracellular proteins such as ras; iii) the cAMP reconstituting agent (8-Br-cAMP) enhancing the pro-apoptotic activity of IFN-alpha. IFN-beta is a multifunctional cytokine binding the same receptor of IFN-alpha, but with higher affinity (10-fold) and differential structural interactions. We recently showed that IFN-beta is considerably more potent than IFN-alpha in its anti-tumour effect through the induction of apoptosis and/or cell cycle arrest in S-phase. The emergence of long-acting pegylated forms of IFN-beta makes this agent a promising anti-cancer drug. These observations open a new scenario of anticancer intervention able to strengthen the antitumor activity of IFN-alpha or to use more potent type I IFNs.