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1.  Role of Apollon in Human Melanoma Resistance to Antitumor Agents That Activate the Intrinsic or the Extrinsic Apoptosis Pathways 
Purpose
To assess the role of Apollon in melanoma resistance to intrinsic and extrinsic pathways of apoptosis and to identify strategies to reduce its expression.
Experimental Design
Apollon expression was assessed in melanoma cells in vitro and in vivo. Apollon modulation and melanoma apoptosis were evaluated by Western blot and/or flow cytometry in response to cytotoxic drugs, mitogen-activated protein/extracellular signal–regulated kinase (MEK)-, BRAFV600E-, and mTOR-specific inhibitors, TRAIL and anti-HLA class II monoclonal antibodies (mAb). Mitochondrial depolarization, caspase activation, apoptosis assays, and gene expression profiling were used to test effects of Apollon silencing, by siRNA, on melanoma response to antitumor agents.
Results
Apollon was constitutively expressed by melanoma cells, in vitro and in vivo, and at higher levels than in benign melanocytic lesions. Melanoma apoptosis correlated significantly with Apollon protein downmodulation in response to cytotoxic drugs, MEK, or BRAFV600E-specific inhibitors. Combinatorial treatment with MEK and mTOR inhibitors and HLA class II ligation, by a specific mAb, promoted Apollon downmodulation and enhanced melanoma apoptosis. Apollon downmodulation induced by antitumor agents was caspase independent, but proteasome dependent. Knockdown of Apollon, by siRNA, triggered apoptosis and/or significantly enhanced melanoma cell death in response to cytotoxic drugs, MEK- and BRAFV600E-specific inhibitors, and soluble or membrane-bound TRAIL. Apollon silencing promoted mitochondrial depolarization and caspase-2, caspase-8, caspase-9, and caspase-3 activation in response to different antitumor agents and altered the profile of genes modulated by MEK or BRAFV600E-specific inhibitors.
Conclusions
Targeting of Apollon may significantly improve melanoma cell death in response to antitumor agents that trigger the intrinsic or the extrinsic apoptosis pathways.
doi:10.1158/1078-0432.CCR-11-2232
PMCID: PMC3426233  PMID: 22553342
2.  Sorafenib Inhibits Lymphoma Xenografts by Targeting MAPK/ERK and AKT Pathways in Tumor and Vascular Cells 
PLoS ONE  2013;8(4):e61603.
The anti-lymphoma activity and mechanism(s) of action of the multikinase inhibitor sorafenib were investigated using a panel of lymphoma cell lines, including SU-DHL-4V, Granta-519, HD-MyZ, and KMS-11 cell lines. In vitro, sorafenib significantly decreased cell proliferation and phosphorylation levels of MAPK and PI3K/Akt pathways while increased apoptotic cell death. In vivo, sorafenib treatment resulted in a cytostatic rather than cytotoxic effect on tumor cell growth associated with a limited inhibition of tumor volumes. However, sorafenib induced an average 50% reduction of tumor vessel density and a 2-fold increase of necrotic areas. Upon sorafenib treatment, endothelial and tumor cells from SU-DHL-4V, Granta-519, and KMS-11 nodules showed a potent inhibition of either phospho-ERK or phospho-AKT, whereas a concomitant inhibition of phospho-ERK and phospho-AKT was only observed in HD-MyZ nodules. In conclusion, sorafenib affects the growth of lymphoid cell lines by triggering antiangiogenic mechanism(s) and directly targeting tumor cells.
doi:10.1371/journal.pone.0061603
PMCID: PMC3631141  PMID: 23620775
3.  Correction: D Quantification of Tumor Vasculature in Lymphoma Xenografts in NOD/SCID Mice Allows to Detect Differences among Vascular-Targeted Therapies 
PLoS ONE  2013;8(4):10.1371/annotation/f61040ca-4eab-4c4c-ad77-0a2ab8c503de.
doi:10.1371/annotation/f61040ca-4eab-4c4c-ad77-0a2ab8c503de
PMCID: PMC3618520
4.  D Quantification of Tumor Vasculature in Lymphoma Xenografts in NOD/SCID Mice Allows to Detect Differences among Vascular-Targeted Therapies 
PLoS ONE  2013;8(3):e59691.
Quantitative characterization of the in vivo effects of vascular-targeted therapies on tumor vessels is hampered by the absence of useful 3D vascular network descriptors aside from microvessel density. In this study, we extended the quantification of planar vessel distribution to the analysis of vascular volumes by studying the effects of antiangiogenic (sorafenib and sunitinib) or antivascular (combretastatin A4 phosphate) treatments on the quantity and spatial distributions of thin microvessels. These observations were restricted to perinecrotic areas of treated human multiple myeloma tumors xenografted in immunodeficient mice and to microvessels with an approximate cross-sectional area lower than 75 µm2. Finally, vessel skeletonization minimized artifacts due to possible differential wall staining and allowed a comparison of the various treatment effects. Antiangiogenic drug treatment reduced the number of vessels of every caliber (at least 2-fold fewer vessels vs. controls; p<0.001, n = 8) and caused a heterogeneous distribution of the remaining vessels. In contrast, the effects of combretastatin A4 phosphate mainly appeared to be restricted to a homogeneous reduction in the number of thin microvessels (not more than 2-fold less vs. controls; p<0.001, n = 8) with marginal effects on spatial distribution. Unexpectedly, these results also highlighted a strict relationship between microvessel quantity, distribution and cross-sectional area. Treatment-specific changes in the curves describing this relationship were consistent with the effects ascribed to the different drugs. This finding suggests that our results can highlight differences among vascular-targeted therapies, providing hints on the processes underlying sample vascularization together with the detailed characterization of a pathological vascular tree.
doi:10.1371/journal.pone.0059691
PMCID: PMC3608557  PMID: 23555747
5.  Detection of minimal residual disease in hematopoietic progenitor cell harvests: lack of predictive value of peripheral blood and bone marrow analysis in mantle cell and indolent lymphoma 
Elimination of neoplastic cells from peripheral blood progenitor cells (PBPCs) is an important issue in transplantation-based high-dose chemotherapy in non Hodgkin’s lymphoma (NHL). The capacity to reliably assess the presence of residual lymphoma cells in PBPCs is mandatory in designing this type of protocols. Polymerase chain reaction (PCR) amplification of molecular rearrangements is widely used to detect minimal residual disease (MRD) in NHL patients. Although concordant data can be obtained in most of the cases from peripheral blood (PB) and bone marrow (BM) at diagnosis, the relationship between these two compartments and the role of their analysis in predicting the molecular status of PBPCs is still an open issue. Here we report data about MRD analysis in BM, PB and PBPCs in a series of mantle cell and indolent NHL patients who underwent high-dose chemotherapy: discordant results were obtained comparing PB, BM and PBPC molecular data. In addition, differences were noted among these results if molecular analysis was performed using well-known rearrangements (i.e., bcl-1/IgH and bcl-2/IgH) or patient specific oligonucleotides. We conclude that neither BM nor PB are reliable in predicting the molecular status of PBPCs and that caution must be adopted in interpreting molecular data obtained using patient specific oligonucleotides.
PMCID: PMC3384403  PMID: 22762029
Minimal residual disease; peripheral blood; bone marrow; peripheral blood progenitor cells

Results 1-5 (5)