Natural killer cell lymphoma shares strikingly similar molecular features with a group of non-hepatosplenic cd T-cell lymphoma and is highly sensitive to a novel aurora kinase A inhibitor in vitro Natural killer (NK) cell lymphomas/leukemias are rare neoplasms with an aggressive clinical behavior. The majority of the cases belong to extranodal NK/T-cell lymphoma, nasal type (ENKTL) in the current WHO classification scheme. Geneexpression profiling (GEP) of 21 ENKTL and NK-cell lymphoma/ leukemia patients, 17 NK-and T-cell lines and 5 indolent NK-cell large-granular-lymphocytic proliferation was performed and compared with 125 peripheral T-cell lymphoma (PTCL) patients previously studied. The molecular classifier derived for ENKTL patients was comprised of 84 transcripts with the majority of them contributed by the neoplastic NK cells. The classifier also identified a set of cd-PTCLs both in the ENKTL cases as well as in cases initially classified as PTCL-not otherwise specified. These cd-PTCLs expressed transcripts associated with the T-cell receptor (TCR)/CD3 complex, suggesting T cell rather than NK-cell lineage. They were very similar to NK-cell tumors by GEP, but were distinct from cytotoxic (ab)-PTCL and hepatosplenic T-cell lymphoma, indicating derivation from an ontogenically and functionally distinct subset of cd T cells. They showed distinct expression of Vc9, Vd2 transcripts and were positive for TCRc, but negative for TCRb by immunohistochemistry. Targeted inhibition of two oncogenic pathways (AURKA and NOTCH-1) by small-molecular inhibitors induced significant growth arrest in NK-cell lines, thus providing a rationale for clinical trials of these inhibitors in NK-cell malignancies.

BackgroundUnderstanding drivers for metastasis in human cancer is important for potential development of therapies to treat metastases. The role of loss of TGFβ tumor suppressor activities in the metastatic process is essentially unknown.Methodology/Principal FindingsUtilizing in vitro and in vivo techniques, we have shown that loss of TGFβ tumor suppressor signaling is necessary to allow the last step of the metastatic process - colonization of the metastatic site. This work demonstrates for the first time that TGFβ receptor reconstitution leads to decreased metastatic colonization. Moreover, we have identified a novel TGFβ/PKA tumor suppressor pathway that acts directly on a known cell survival mechanism that responds to stress with the survivin/XIAP dependent inhibition of caspases that effect apoptosis. The linkage between the TGFβ/PKA transduceome signaling and control of metastasis through induction of cell death was shown by TGFβ receptor restoration with reactivation of the TGFβ/PKA pathway in receptor deficient metastatic colon cancer cells leading to control of aberrant cell survival.Conclusion/SignificanceThis work impacts our understanding of the possible mechanisms that are critical to the growth and maintenance of metastases as well as understanding of a novel TGFβ function as a metastatic suppressor. These results raise the possibility that regeneration of attenuated TGFβ signaling would be an effective target in the treatment of metastasis. Our work indicates the clinical potential for developing anti-metastasis therapy based on inhibition of this very important aberrant cell survival mechanism by the multifaceted TGFβ/PKA transduceome induced pathway. Development of effective treatments for metastatic disease is a pressing need since metastases are the major cause of death in solid tumors.

Survivin is a cancer-associated gene that functions to promote cell survival, cell division, and angiogenesis and is a marker of poor prognosis. Histone deacetylase inhibitors induce apoptosis and re-expression of epigenetically silenced tumor suppressor genes in cancer cells. In association with increased expression of the tumor suppressor gene transforming growth factor ␤ receptor II (TGF␤RII) induced by the histone deacetylase inhibitor belinostat, we observed repressed survivin expression. We investigated the molecular mechanisms involved in survivin down-regulation by belinostat downstream of reactivation of TGF␤ signaling. We identified two mechanisms. At early time points, survivin protein half-life was decreased with its proteasomal degradation. We observed that belinostat activated protein kinase A at early time points in a TGF␤ signaling-dependent mechanism. After longer times (48 h), survivin mRNA was also decreased by belinostat. We made the novel observation that belinostat mediated cell death through the TGF␤/protein kinase A signaling pathway. Induction of TGF␤RII with concomitant survivin repression may represent a significant mechanism in the anticancer effects of this drug. Therefore, patient populations exhibiting high survivin expression with epigenetically silenced TGF␤RII might potentially benefit from the use of this histone deacetylase inhibitor.The mutational events involved in the initiation and progression of colorectal cancer have been well documented (1). However, it is now recognized that in addition to these alterations in DNA sequence epigenetic modifications of the genome play a major role in contributing to the malignant phenotype (1, 2). The critical balance between histone acetylation by histone acetyltransferases and deacetylation by histone deacetylases (HDACs) 3 represents a key epigenetic layer involved in gene regulation (3). The class I HDACs are overexpressed in many tumor types compared with normal tissues (4), and this overexpression is generally associated with poor prognosis (5, 6). These findings have resulted in the development of drugs that target HDACs. The second generation HDAC inhibitors (HDACis) target class I and II HDACs. These drugs induce differentiation, cell growth arrest, and apoptosis in cell lines in vitro and in vivo indicating that the increased activity of these enzymes in cancer contributes to tumor progression (7-9). However, the key mechanisms and pathways through which HDAC inhibition leads to tumor cell apoptosis have not been well defined.Transforming growth factor ␤ (TGF␤) signaling has been shown to contribute to a variety of cellular functions including growth inhibition and induction of differentiation and apoptosis as well as cell motility and adhesion (10). It has been demonstrated that transcriptional loss of TGF␤ receptor expression leading to attenuation of TGF␤ signaling is a frequent occurrence in a wide range of cancers in vitro and in vivo and is associated with poor patient prognosis (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(...

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Systemic AAV (adeno-associated virus) gene therapy is a promising approach for the treatment of inborn errors of metabolism, but questions remain regarding its potency and durability. Tolerogenic ImmTOR nanoparticles encapsulating rapamycin have been shown to block the formation of neutralizing anti-capsid antibodies, thereby enabling vector re-administration. Here, we further demonstrate that ImmTOR admixed with AAV vectors also enhances hepatic transgene expression at the initial dose of AAV vector, independent of its effects on adaptive immunity. ImmTOR enhances AAV trafficking to the liver, resulting in increased hepatic vector copy numbers and transgene mRNA expression. Enhanced transgene expression occurs through a mechanism independent of the AAV receptor and cannot be replicated in vivo with free rapamycin or empty nanoparticles. The multipronged mechanism of ImmTOR action makes it an attractive candidate to enable more efficient transgene expression at first dose while simultaneously inhibiting adaptive responses against AAV to enable repeat dosing.

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A major barrier to adeno-associated virus (AAV) gene therapy is the inability to re-dose patients due to formation of vectorinduced neutralizing antibodies (Nabs). Tolerogenic nanoparticles encapsulating rapamycin (ImmTOR) provide long-term and specific suppression of adaptive immune responses, allowing for vector re-dosing. Moreover, co-administration of hepatotropic AAV vectors and ImmTOR leads to an increase of transgene expression even after the first dose. ImmTOR and AAV Anc80 encoding the methylmalonyl-coenzyme A (CoA) mutase (MMUT) combination was tested in a mouse model of methylmalonic acidemia, a disease caused by mutations in the MMUT gene. Repeated co-administration of Anc80 and ImmTOR was well tolerated and led to nearly complete inhibition of immunoglobulin (Ig)G antibodies to the Anc80 capsid. A more profound decrease of plasma levels of the key toxic metabolite, plasma methylmalonic acid (pMMA), and disease biomarker, fibroblast growth factor 21 (FGF21), was observed after treatment with the ImmTOR and Anc80-MMUT combination. In addition, there were higher numbers of viral genomes per cell (vg/cell) and increased transgene expression when ImmTOR was co-administered with Anc80-MMUT. These effects were dose-dependent, with the higher doses of Im-mTOR providing higher vg/cell and mRNA levels, and an improved biomarker response. Combining of ImmTOR and AAV can not only block the IgG response against capsid, but it also appears to potentiate transduction and enhance therapeutic transgene expression in the mouse model.

Selective small-molecule kinase inhibitors have encouraging clinical efficacy in several malignancies. These agents are still limited to a subset of patients, indicating the need to develop therapeutic biomarkers that influence clinical benefit. In this study, we demonstrate that treatment with MK-8745, a novel Aurora-A specific inhibitor, leads to cell cycle arrest at the G2/M phase with accumulation of tetraploid nuclei followed by cell death in non-Hodgkin lymphoma (NHL) cell lines. The sensitivity of the cell lines to MK-8745 is correlated with the expression level of Aurora-A activator. The siRNA knockdown of Aurora-A activator TPX2 (targeting protein for Xenopus kinase-like protein 2) increased MK-8745 sensitivity in less-MK-8745-sensitive NHL cell lines, whereas overexpression of TPX2 in high-MK-8745-sensitive NHL cell lines increased drug resistance. Our results indicate that TPX2 may serve as a biomarker for identifying subpopulations of patients sensitive to Aurora-A inhibitor treatment.