Downregulation of imidacloprid resistant genes alters the biological parameters in Colorado potato beetle, Leptinotarsa decemlineata Say (chrysomelidae: Coleoptera).

Colorado potato beetle, Leptinotarsa decemlineata Say (coleoptera: chrysomelidae), is the important pest of potato all over the world. This insect pest is resistant to more than 50 active compounds belonging to various chemical groups. Potential of RNA interference (RNAi) was explored to knock down transcript levels of imidacloprid resistant genes in Colorado potato beetle (CPB) under laboratory conditions. Three important genes belonging to cuticular protein (CP), cytochrome P450 monoxygenases (P450) and glutathione synthetase (GSS) families encoding imidacloprid resistance were targeted. Feeding bio-assays were conducted on various stages of imidacloprid resistant CPB lab population by applying HT115 expressing dsRNA on potato leaflets. Survival rate of insects exposed to CP-dsRNA decreased to 4.23%, 15.32% and 47.35% in 2nd, 3rd and 4th instar larvae respectively. Larval weight and pre-adult duration were also affected due to dsRNAs feeding. Synergism of RNAi with imidacloprid conducted on the 2nd instar larvae, exhibited 100% mortality of larvae when subjected to reduced doses of GSS and CP dsRNAs along with imidacloprid. Utilization of three different dsRNAs against imidacloprid resistant CPB population reveal that dsRNAs targeting CP, P450 and GSS enzymes could be useful tool in management of imidacloprid resistant CPB populations.

Chemical enhancers of posttranscriptional gene silencing in Arabidopsis.

RNAi mediated by small-interfering RNAs (siRNAs) operates via transcriptional (TGS) and posttranscriptional gene silencing (PTGS). In Arabidopsis thaliana, TGS relies on DICER-LIKE-3 (DCL3)-dependent 24-nt siRNAs loaded into AGO4-clade ARGONAUTE effector proteins. PTGS operates via DCL4-dependent 21-nt siRNAs loaded into AGO1-clade proteins. We set up and validated a medium-throughput, semi-automatized procedure enabling chemical screening, in a 96-well in vitro format, of Arabidopsis transgenic seedlings expressing an inverted-repeat construct from the phloem companion cells. The ensuing quantitative PTGS phenotype was exploited to identify molecules, which, upon topical application, either inhibit or enhance siRNA biogenesis/activities. The vast majority of identified modifiers were enhancers, among which Sortin1, Isoxazolone, and [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) provided the most robust and consistent results, including upon their application onto soil-grown plants in which their effect was nonautonomous and long lasting. The three molecules increased the RNAi potency of the inverted-repeat construct, in large part by enhancing 21-nt siRNA accumulation and loading into AGO1, and concomitantly reducing AGO4 and DCL3 levels in planta. A similar, albeit not identical effect, was observed on 22-nt siRNAs produced from a naturally occurring inverted-repeat locus, demonstrating that the molecules also enhance endogenous PTGS. In standardized assays conducted in seedling extracts, the three enhancers selectively increased DCL4-mediated processing of in vitro-synthesized double-stranded RNAs, indicating the targeting of a hitherto unknown PTGS component probably independent of the DCL4-cofactor DOUBLE-STRANDED RNA-BINDING 4 (DRB4). This study establishes the proof-of-concept that RNAi efficacy can be modulated by chemicals in a whole organism. Their potential applications and the associated future research are discussed.

Integration of RNAi and Small Molecule Screens to Identify Targets for Drug Development.

Cellular models for siRNA and small molecule high-throughput screening have been widely used in the last decade to identify targets for drug discovery. As an example, we present a twofold readout approach based on cell viability and multipolar phenotype. To maximize the discovery of potential targets and at the same time reduce the number of false positives in our dataset, we have combined focused and rationally designed custom siRNA libraries with small molecule inhibitor libraries. Here we describe a cellular model for centrosome amplification as an example of how to design and perform a multiple readout/multiple screening strategy.

Proteomic Analysis and Functional Studies of Baicalin on Proteins Associated with Skin Cancer.

Abundant evidence supports the key role of ultraviolet radiation (UVR) in skin cancer development. The human skin, especially the epidermal layer, is the main defense against UV radiation. Baicalin is a major bioactive component of Scutellaria baicalensis Georgi, a plant which has been found to exhibit antitumor activity. The anticarcinogenic mechanism of baicalin is not completely understood. We have reported that baicalin inhibited UVB-induced photo-damage and apoptosis in HaCaT cells (human skin keratinocytes). The aim of the present study is to investigate the cellular gene targets responsible for baicalin's antitumor activity by performing two-dimensional electrophoresis liquid chromatography-mass spectrometry/mass spectrometry (2-DE LC-MS/MS) with HaCaT cells following UVB and baicalin exposure. Two-DE for protein separation was performed, followed by matrix-assisted laser desorption/ionization mass spectrometry and database searches. Nucleophosmin (NPM)-specific siRNA was designed and synthesized, and the small interfering RNA was transfected into skin squamous cancer A431 cells to knockdown the NPM expression. Proliferation and cell cycle status were assessed by CCK8 and flow cytometric analyses, respectively. We have identified 38 protein spots that are differentially expressed in HaCaT cells exposed to baicalin and/or UVB irradiation These proteins are involved in detoxification, proliferation, metabolism, cytoskeleton and motility. In particular, we found several proteins that have been linked to tumor progression and resistance, such as NPM. Baicalin treatment reduced the cellular proliferation rate and induced arrest during the S-phase of the cell cycle in A431 cells. NPM1 silencing significantly enhanced the effect of baicalin. Our data indicated that baicalin results in the significant inhibition of tumor growth in the A431 cell line, which may be associated with the regulation of the NPM gene expression.

Developing an in vivo toxicity assay for RNAi risk assessment in honey bees, Apis mellifera L.

Maize plants expressing dsRNA for the management of Diabrotica virgifera virgifera are likely to be commercially available by the end of this decade. Honey bees, Apis mellifera, can potentially be exposed to pollen from transformed maize expressing dsRNA. Consequently, evaluation of the biological impacts of RNAi in honey bees is a fundamental component for ecological risk assessment. The insecticidal activity of a known lethal dsRNA target for D. v. virgifera, the vATPase subunit A, was evaluated in larval and adult honey bees. Activity of both D. v. virgifera (Dvv)- and A. mellifera (Am)-specific dsRNA was tested by dietary exposure to dsRNA. Larval development, survival, adult eclosion, adult life span and relative gene expression were evaluated. The results of these tests indicated that Dvv vATPase-A dsRNA has limited effects on larval and adult honey bee survival. Importantly, no effects were observed upon exposure of Am vATPase-A dsRNA suggesting that the lack of response involves factors other than sequence specificity. The results from this study provide guidance for future RNAi risk analyses and for the development of a risk assessment framework that incorporates similar hazard assessments.

Screening for Small-Molecule Modulators of Long Noncoding RNA-Protein Interactions Using AlphaScreen.

Long non-protein coding RNAs (lncRNAs) are an important class of molecules that help orchestrate key cellular events. Although their functional roles in cells are not well understood, thousands of lncRNAs and a number of possible mechanisms by which they act have been reported. LncRNAs can exert their regulatory function in cells by interacting with epigenetic enzymes. In this study, we developed a tool to study lncRNA-protein interactions for high-throughput screening of small-molecule modulators using AlphaScreen technology. We tested the interaction of two lncRNAs: brain-derived neurotrophic factor antisense (BDNF-AS) and Hox transcript antisense RNA (HOTAIR), with Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase against a phytochemical library, to look for small-molecule inhibitors that can alter the expression of downstream target genes. We identified ellipticine, a compound that up-regulates BDNF transcription. Our study shows the feasibility of using high-throughput screening to identify modulators of lncRNA-protein interactions and paves the road for targeting lncRNAs that are dysregulated in human disorders using small-molecule therapies.

Preclinical and clinical development of siRNA-based therapeutics.

The discovery of RNA interference, first in plants and Caenorhabditis elegans and later in mammalian cells, led to the emergence of a transformative view in biomedical research. Knowledge of the multiple actions of non-coding RNAs has truly allowed viewing DNA, RNA and proteins in novel ways. Small interfering RNAs (siRNAs) can be used as tools to study single gene function both in vitro and in vivo and are an attractive new class of therapeutics, especially against undruggable targets for the treatment of cancer and other diseases. Despite the potential of siRNAs in cancer therapy, many challenges remain, including rapid degradation, poor cellular uptake and off-target effects. Rational design strategies, selection algorithms, chemical modifications and nanocarriers offer significant opportunities to overcome these challenges. Here, we review the development of siRNAs as therapeutic agents from early design to clinical trial, with special emphasis on the development of EphA2-targeting siRNAs for ovarian cancer treatment.

A rice calcium-dependent protein kinase OsCPK9 positively regulates drought stress tolerance and spikelet fertility.

BACKGROUND: In plants, calcium-dependent protein kinases (CDPKs) are involved in tolerance to abiotic stresses and in plant seed development. However, the functions of only a few rice CDPKs have been clarified. At present, it is unclear whether CDPKs also play a role in regulating spikelet fertility. RESULTS: We cloned and characterized the rice CDPK gene, OsCPK9. OsCPK9 transcription was induced by abscisic acid (ABA), PEG6000, and NaCl treatments. The results of OsCPK9 overexpression (OsCPK9-OX) and OsCPK9 RNA interference (OsCPK9-RNAi) analyses revealed that OsCPK9 plays a positive role in drought stress tolerance and spikelet fertility. Physiological analyses revealed that OsCPK9 improves drought stress tolerance by enhancing stomatal closure and by improving the osmotic adjustment ability of the plant. It also improves pollen viability, thereby increasing spikelet fertility. In OsCPK9-OX plants, shoot and root elongation showed enhanced sensitivity to ABA, compared with that of wild-type. Overexpression and RNA interference of OsCPK9 affected the transcript levels of ABA- and stress-responsive genes. CONCLUSIONS: Our results demonstrated that OsCPK9 is a positive regulator of abiotic stress tolerance, spikelet fertility, and ABA sensitivity.

RNAi-mediated silencing of hepatic Alas1 effectively prevents and treats the induced acute attacks in acute intermittent porphyria mice.

The acute hepatic porphyrias are inherited disorders of heme biosynthesis characterized by life-threatening acute neurovisceral attacks. Factors that induce the expression of hepatic 5-aminolevulinic acid synthase 1 (ALAS1) result in the accumulation of the neurotoxic porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG), which recent studies indicate are primarily responsible for the acute attacks. Current treatment of these attacks involves i.v. administration of hemin, but a faster-acting, more effective, and safer therapy is needed. Here, we describe preclinical studies of liver-directed small interfering RNAs (siRNAs) targeting Alas1 (Alas1-siRNAs) in a mouse model of acute intermittent porphyria, the most common acute hepatic porphyria. A single i.v. dose of Alas1-siRNA prevented the phenobarbital-induced biochemical acute attacks for approximately 2 wk. Injection of Alas1-siRNA during an induced acute attack significantly decreased plasma ALA and PBG levels within 8 h, more rapidly and effectively than a single hemin infusion. Alas1-siRNA was well tolerated and a therapeutic dose did not cause hepatic heme deficiency. These studies provide proof-of-concept for the clinical development of RNA interference therapy for the prevention and treatment of the acute attacks of the acute hepatic porphyrias.

Synergistic anticancer effect of RNAi and photothermal therapy mediated by functionalized single-walled carbon nanotubes.

Single-walled carbon nanotubes (SWNTs) are special nano-materials which exhibit interesting physical and chemical properties, presenting new opportunities for biomedical research and applications. In this study, we have successfully adopted a novel strategy to chemically functionalize SWNTs with polyethylenimine (PEI) through purification, oxidation, amination and polymerization, which were then bound by DSPE-PEG2000-Maleimide for further conjugation with the tumor targeting NGR (Cys-Asn-Gly-Arg-Cys-) peptide via the maleimide group and sulfhydryl group of cysteine, and finally hTERT siRNA was loaded to obtain a novel tumor targeting siRNA delivery system, designated as SWNT-PEI/siRNA/NGR. The results showed that SWNT-PEI/siRNA/NGR could efficiently cross cell membrane, induced more severe apoptosis and stronger suppression in proliferation of PC-3 cells in vitro. Furthermore, in tumor-bearing mice model the delivery system exhibited higher antitumor activity due to more accumulation in tumor without obvious toxicity in main organs. The combination of RNAi and near-infrared (NIR) photothermal therapy significantly enhanced the therapeutic efficacy. In conclusion, SWNT-PEI/siRNA/NGR is a novel and promising anticancer system by combining gene therapy and photothermal therapy.

The important roles of RET, VEGFR2 and the RAF/MEK/ERK pathway in cancer treatment with sorafenib.

AIM: To elucidate the roles of receptor tyrosine kinases RET and VEGFR2 and the RAF/MEK/ERK signaling cascade in cancer treatment with sorafenib. METHODS: The cell lines A549, HeLa, and HepG2 were tested. The enzyme activity was examined under cell-free conditions using 384-well microplate assays. Cell proliferation was evaluated using the Invitrogen Alarmar Blue assay. Gene expression was analyzed using the Invitrogen SYBR Green expression assays with a sequence detection system. Protein expression analysis was performed using Western blotting. RESULTS: Sorafenib potently suppressed the activities of cRAF, VEGFR2, and RET with IC(50) values of 20.9, 4 and 0.4 nmol/L, respectively. Sorafenib inhibited cRAF, VEGFR2, and RET via non-ATP-competitive, ATP-competitive and mixed-type modes, respectively. In contrast, sorafenib exerted only moderate cytotoxic effects on the proliferation of the 3 cell lines. The IC(50) values for inhibition of A549, HeLa, and HepG2 cells were 8572, 4163, and 8338 nmol/L, respectively. In the 3 cell lines, sorafenib suppressed the cell proliferation mainly by blocking the MEK/ERK downstream pathway at the posttranscriptional level, which in turn regulated related gene expression via a feed-back mechanism. CONCLUSION: This study provides novel evidence that protein kinases RET and VEGFR2 play crucial roles in cancer treatment with sorafenib.

[Activating effect of citrus flavonoids on neuromedin U2 receptor and analysis on siRNA interference].

OBJECTIVE: To screen out active substances on Neuromedin U2 receptor (NMU2R) by using stable NMU2R cell lines and negative cell lines and analyzing siRNA interference. METHOD: NMU2R cells were used to observe the activating effect of nine nine citrus flavonoids on NMU2R cell. Afterwards, false-positive interference of citrus flavonoids that showed higher activating effect was eliminated by using negative cells and analyzing the efficiency of siRNA interference. RESULT: Hesperidin and nobiletin contained in citrus flavonoids were found to effectively activate NMU2R. The efficacy, EC50 and potency values of hesperidin were 4.688, 318.970 micromol x L(-1) and 200.933 micromol x L(-1), while the efficacy, EC50 and potency values of nobiletin were 4.758, 5.832 micromol x L(-1) and 3.124 micromol x L(-). CONCLUSION: Hesperidin and nobiletin contained in citrus flavonoids can activate NMU2R. Nobiletin shows such a low EC50 that it has medicinal value.

Proteomic analysis of aorta and protective effects of grape seed procyanidin B2 in db/db mice reveal a critical role of milk fat globule epidermal growth factor-8 in diabetic arterial damage.

BACKGROUND: Atherosclerosis is one of the major complications of type 2 diabetic patients (T2DM), leading to morbidity and mortality. Grape seed procyanidin B2 (GSPB2) has demonstrated protective effect against atherosclerosis, which is believed to be, at least in part, a result of its antioxidative effects. The aim of this study is to identify the target protein of GSPB2 responsible for the protective effect against atherosclerosis in patients with DM. METHODS AND RESULTS: GSPB2 (30 mg/kg body weight/day) were administrated to db/db mice for 10 weeks. Proteomics of the aorta extracts by iTRAQ analysis was obtained from db/db mice. The results showed that expression of 557 proteins were either up- or down-regulated in the aorta of diabetic mice. Among those proteins, 139 proteins were normalized by GSPB2 to the levels comparable to those in control mice. Among the proteins regulated by GSPB2, the milk fat globule epidermal growth factor-8 (MFG-E8) was found to be increased in serum level in T2DM patients; the serum level of MFG-E8 was positively correlated with carotid-femoral pulse wave velocity (CF-PWV). Inhibition of MFG-E8 by RNA interference significantly suppressed whereas exogenous recombinant MFG-E8 administration exacerbated atherogenesis the db/db mice. To gain more insights into the mechanism of action of MFG-E8, we investigated the effects of MFG-E8 on the signal pathway involving the extracellular signal-regulated kinase (ERK) and monocyte chemoattractant protein-1 (MCP-1). Treatment with recombinant MFG-E8 led to increased whereas inhibition of MFG-E8 to decreased expression of MCP-1 and phosphorylation of ERK1/2. CONCLUSION: Our data suggests that MFG-E8 plays an important role in atherogenesis in diabetes through both ERK and MCP-1 signaling pathways. GSPB2, a well-studied antioxidant, significantly inhibited the arterial wall changes favoring atherogenesis in db/db mice by down-regulating MFG-E8 expression in aorta and its serum level. Measuring MFG-E8 serum level could be a useful clinical surrogate prognosticating atherogenesis in DM patients.

Toxicity modelling of Plk1-targeted therapies in genetically engineered mice and cultured primary mammalian cells.

High attrition rates of novel anti-cancer drugs highlight the need for improved models to predict toxicity. Although polo-like kinase 1 (Plk1) inhibitors are attractive candidates for drug development, the role of Plk1 in primary cells remains widely unexplored. Therefore, we evaluated the utility of an RNA interference-based model to assess responses to an inducible knockdown (iKD) of Plk1 in adult mice. Here we show that Plk1 silencing can be achieved in several organs, although adverse events are rare. We compared responses in Plk1-iKD mice with those in primary cells kept under controlled culture conditions. In contrast to the addiction of many cancer cell lines to the non-oncogene Plk1, the primary cells' proliferation, spindle assembly and apoptosis exhibit only a low dependency on Plk1. Responses to Plk1-depletion, both in cultured primary cells and in our iKD-mouse model, correspond well and thus provide the basis for using validated iKD mice in predicting responses to therapeutic interventions.

Metabolically engineered male sterility in rapeseed (Brassica napus L.).

Male sterility is of special interest as a mechanism allowing hybrid breeding, especially in important crops such as rapeseed (Brassica napus). Male sterile plants are also suggested to be used as a biological safety method to prevent the spread of transgenes, a risk that is high in the case of rapeseed due to the mode of pollination, out-crossing by wind or insects, and the presence of related, cross-pollinating species in the surrounding ecosystem in Europe. Different natural occurring male sterilities and alloplasmic forms have been tried to be used in rapeseed with more or less success. Due to the difficulties and limitations with these systems, we present a biotechnological alternative: a metabolically engineered male sterility caused by interference with anther-specific cell wall-bound invertase. This is an essential enzyme for carbohydrate supply of the symplastically isolated pollen. The activity of this enzyme is reduced either by antisense interference or by expressing an invertase inhibitor under control of the anther-specific promoter of the invertase with the consequence of a strong decrease of pollen germination ability.

A Drosophila model of Menkes disease reveals a role for DmATP7 in copper absorption and neurodevelopment.

Human Menkes disease is a lethal neurodegenerative disorder of copper metabolism that is caused by mutations in the ATP7A copper-transporting gene. In the present study, we attempted to construct a Drosophila model of Menkes disease by RNA interference (RNAi)-induced silencing of DmATP7, the Drosophila orthologue of mammalian ATP7A, in the digestive tract. Here, we show that a lowered level of DmATP7 mRNA in the digestive tract results in a reduced copper content in the head and the rest of the body of surviving adults, presumably owing to copper entrapment in the gut. Similar to Menkes patients, a majority of flies exhibit an impaired neurological development during metamorphosis and die before eclosion. In addition, we show that survival to the adult stage is highly dependent on the copper content of the food and that overexpression of the copper homeostasis gene, metal-responsive transcription factor-1 (MTF-1), enhances survival to the adulthood stage. Taken together, these results highlight the role of DmATP7-mediated copper uptake in the neurodevelopment of Drosophila melanogaster and provide a framework for the analysis of potential gene interactions influencing Menkes disease.

A model to identify novel targets involved in oxidative stress-induced apoptosis in human lung epithelial cells by RNA interference.

Chronic obstructive pulmonary disease (COPD) is an increasing health problem primarily associated with cigarette smoking, and one of the leading causes of morbidity and mortality worldwide. Despite recent advances in understanding the pathogenesis of the disease, overall patient outcome remains poor with limited therapeutic intervention. Chronic inflammation, an imbalance between proteolytic and anti-proteolytic activities (leading to lung parenchyma destruction) and excessive oxidative stress contribute to COPD pathophysiology. Oxidative stress-triggered apoptosis of alveolar structural cells, including epithelial cells, may be an important event in the development of COPD. In this study, we developed a cell-based oxidative stress-induced apoptosis assay and performed a high-throughput screen (HTS) using a human druggable genome siRNA library. Our results have identified potential novel pathways (e.g. unfolded protein response, proteosomal activity) and targets (e.g. MAP3K14, HMGB2) that regulate the response of lung epithelial cells to oxidative stress. This assay has proven to be a useful tool for the identification of potential new therapeutic targets for lung disease.

Replication protein A (RPA1a) is required for meiotic and somatic DNA repair but is dispensable for DNA replication and homologous recombination in rice.

Replication protein A (RPA), a highly conserved single-stranded DNA-binding protein in eukaryotes, is a stable complex comprising three subunits termed RPA1, RPA2, and RPA3. RPA is required for multiple processes in DNA metabolism such as replication, repair, and homologous recombination in yeast (Saccharomyces cerevisiae) and human. Most eukaryotic organisms, including fungi, insects, and vertebrates, have only a single RPA gene that encodes each RPA subunit. Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa), however, possess multiple copies of an RPA gene. Rice has three paralogs each of RPA1 and RPA2, and one for RPA3. Previous studies have established their biochemical interactions in vitro and in vivo, but little is known about their exact function in rice. We examined the function of OsRPA1a in rice using a T-DNA insertional mutant. The osrpa1a mutants had a normal phenotype during vegetative growth but were sterile at the reproductive stage. Cytological examination confirmed that no embryo sac formed in female meiocytes and that abnormal chromosomal fragmentation occurred in male meiocytes after anaphase I. Compared with wild type, the osrpa1a mutant showed no visible defects in mitosis and chromosome pairing and synapsis during meiosis. In addition, the osrpa1a mutant was hypersensitive to ultraviolet-C irradiation and the DNA-damaging agents mitomycin C and methyl methanesulfonate. Thus, our data suggest that OsRPA1a plays an essential role in DNA repair but may not participate in, or at least is dispensable for, DNA replication and homologous recombination in rice.

Inhibition of dicing of guanosine-rich shRNAs by quadruplex-binding compounds.

RNA interference is triggered by small hairpin precursors that are processed by the endonuclease dicer to yield active species such as siRNAs and miRNAs. To regulate the RNAi-mediated suppression of gene expression, we imagined a strategy that relies on the sequence-specific inhibition of shRNA precursor processing by immediate RNA-small molecule interactions. Here, we present a first step in this direction by augmenting shRNAs with guanosine-rich sequences that are prone to fold into four-stranded structures. The addition of small molecules that selectively bind to such quadruplex sequences should allow for the specific inhibition of dicing of shRNAs that contain suitable G-rich elements. In an attempt to find compounds that protect against dicer processing, we have examined the effects of quadruplex-binding compounds on the dicer processing of shRNAs containing G-quadruplexes. Although a variety of small molecules that are known to bind to quadruplexes inhibited in vitro dicing of shRNAs, only two substance classes, namely certain porphyrazines and bisquinolinium compounds, showed selective inhibition of G-rich shRNAs compared to control sequences lacking guanine-rich elements. The G-rich shRNAs displayed a potent knockdown of gene expression in mammalian cell culture, but the effect was not influenced by addition of the respective quadruplex-binding compounds.

Aurora A kinase RNAi and small molecule inhibition of Aurora kinases with VE-465 induce apoptotic death in multiple myeloma cells.

The expression of RHAMM and other centrosome-associated genes are known to correlate with the extent of centrosome amplification in multiple myeloma, and with poor prognosis. RHAMM has a significant interaction with TPX2, a protein which regulates the localization and action of Aurora A kinase (AURKA) at the spindle poles. AURKA is known to be a central determinant of centrosome and spindle function and is a target for cancer therapy. Given these observations, we investigated the role of Aurora kinases as therapeutic targets in myeloma. Here we report that AURKA is expressed ubiquitously in myeloma, to varying degrees, in both cell lines and patients' bone marrow plasma cells. siRNA targeting AURKA induces apoptotic cell death in myeloma cell lines. The Aurora kinase inhibitor VE-465 also induces apoptosis and death in myeloma cell lines and primary myeloma plasma cells. The combination of VE-465 and dexamethasone improves cell killing compared with the use of either agent alone, even in cells resistant to the single agents. The phenotype of myeloma cells treated with VE-465 is consistent with published reports on the effects of Aurora kinase inhibition. Aurora kinase inhibitors should be pursued as potential treatments for myeloma.