Valproic Acid (VPA), a Histone Deacetylase (HDAC) Inhibitor, Diminishes Lymphoproliferation in the Fas Deficient MRL/lpr−/− Murine Model of Autoimmune Lymphoproliferative Syndrome (ALPS).

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2497-2497
Author(s):  
Kennichi C. Dowdell ◽  
Lesley Pesnicak ◽  
Victoria Hoffman ◽  
Kenneth Steadman ◽  
Mark Ruddel ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Cell Death ◽  
Lymph Nodes ◽  
Histone Deacetylase ◽  
Murine Model ◽  
Hdac Inhibitor ◽  
Vitro Assay ◽  
Type Ia ◽  
Autoimmune Cytopenias

Abstract ALPS is an inherited disorder of apoptosis leading to lymphoproliferation and autoimmunity. ALPS Type Ia, Ib and II are associated with germline mutations in Fas, FasL and Casapase 8 or 10, respectively; patients in whom no mutations have been identified are classified as Type III. The vast majority of patients are ALPS Type Ia (greater than 70%). They often present with childhood onset autoimmune cytopenias associated with lymphadenopathy, splenomegaly, increased double negative T cells (DNT; TCRα/β+CD3+CD4−CD8−), defective apoptosis by in vitro assay, and have an increased risk of lymphoma. Similarly, MRL/lpr−/− mice homozygous for Fas mutations develop an ALPS-like disease with massive lymphadenopathy, splenomegaly, hypergammaglobulinemia, autoimmune glomerulonephritis, and expansion of DNT cells secondary to defective lymphocyte apoptosis leading to lymphomagenesis. Currently, there are no proven therapies for the lymphoproliferation underlying ALPS itself, although complications like autoimmune cytopenias and post-splenectomy sepsis are manageable. Hence, studies were conducted to determine the efficacy of valproic acid (VPA) to control the lymphoproliferation associated with ALPS. VPA is a histone deacetylase (HDAC) inhibitor in clinical use for the last four decades as an anticonvulsant in children and adults, and recently being explored as an anti-neoplastic agent. PBMCs from normal controls and ALPS Type Ia patients were cultured in vitro with 0–4 mM VPA in the presence or absence of 50 uM of the pan-caspase inhibitor Z-VAD-FMK. A dose response was observed with a high degree of cell death noted at 4 mM after 48 hours, with an LD50 of 2 mM. VPA appeared to induce cell death by both caspase-dependent and -independent mechanisms based on partial inhibition of VPA-induced cell death by Z-VAD-FMK. Further preclinical studies were conducted in the MRL/lpr−/− murine model of ALPS. Twenty, 8-week old female MRL/lpr−/− mice were treated intraperitoneally (i.p.) with 500 mg/kg of VPA in sterile PBS or PBS alone five days per week for 8 weeks. Significant reduction of the spleen weight (p=0.034) and cellularity (p=0.0001) was observed in VPA treated (n=10) mice compared to controls (n=10). Reductions in size and cellularity were also observed in the lymph nodes (p=0.09 and 0.0002, respectively). A concomitant decrease (p<0.05) in DNT cells was observed in the spleen (11.2±0.6 vs 8.1±0.4) and blood (9.3±0.96 vs 5.5±0.6). Serum drug levels peaked (462±10 ug/mL) by 2 hours post-i.p. injection of VPA, where-as a 2.5 fold increase in histone acetylation was observed in the spleen at 4 hours, following a single injection. Analysis of the effects of VPA on autoimmune renal disease in these animals is underway. Based on our in vitro and in vivo data, VPA is effective at reducing lymphoproliferative activity in Fas deficient MRL/lpr−/− mice. It is being further explored in early phase clinical trials as a lympholytic agent to shrink lymph nodes and abrogate hypersplenism in ALPS patients.

Hydroxychloroquine Diminishes Lymphoproliferation in the Fas Deficient MRL/lpr−/− Murine Model of Autoimmune Lymphoproliferative Syndrome (ALPS).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1385-1385 ◽  
Author(s):  
Kennichi C. Dowdell ◽  
Lesley Pesnicak ◽  
Lilia Bi ◽  
Victoria Hoffmann ◽  
V. Koneti Rao ◽  
...  
Keyword(s):  
Cell Death ◽  
Lymph Nodes ◽  
Murine Model ◽  
High Dose ◽  
Polymorphonuclear Cells ◽  
Increased Risk ◽  
Type Ia ◽  
Autoimmune Cytopenias ◽  
Steroid Sparing

Abstract Hydroxychloroquine (HCQ) is an anti-malarial drug in clinical use for decades that is finding further use as a steroid sparing agent in the treatment of immune disorders such as chronic GVHD, lupus and rheumatoid arthritis. HCQ is a lysosomotropic agent with more recent evidence showing immunomodulatory anti-TNF activity. It is currently being explored as a cytotoxic antineoplastic/antimicrobial agent. Hence, studies were conducted to determine the efficacy of HCQ to control the lymphoproliferation associated with ALPS. ALPS is an inherited disorder of apoptosis leading to lymphoproliferation and autoimmunity. The majority of ALPS patients are classified as Type Ia (>70%), having germline mutations in Fas. Other ALPS patients are classified as Type Ib, II, IV or III, if they have mutations in FasL, casapases, NRAS, or no identified mutations, respectively. They often present with childhood onset autoimmune cytopenias with lymphadenopathy, splenomegaly, increased circulating double negative T cells (DNT; TCRa/b+CD3+CD4−CD8−), defective apoptosis in vitro, and have an increased risk of lymphoma. Similarly, MRL/lpr−/− mice homozygous for Fas mutations develop an ALPS-like disease with massive lymphadenopathy, splenomegaly, hypergammaglobulinemia, autoimmune glomerulonephritis, and expansion of DNT cells secondary to defective lymphocyte apoptosis leading to lymphomagenesis. Currently, there are no proven therapies for the lymphoproliferation underlying ALPS itself. PBMCs from normal controls and ALPS Type Ia patients were cultured in vitro with 0–120 ug/mL HCQ in the presence or absence of 50 uM of the pan-caspase inhibitor Z-VAD-FMK, the caspase 9 inhibitor Z-LEHD-FMK, or the caspase 8 inhibitor Z-IETD-FMK. A dose response was observed with a high degree of cell death noted at 120 ug/mL after 48 hours, with an LD50 of 40 ug/mL. HCQ induced cell death was through a caspase-independent mechanism based on no inhibition of cell death by Z-VAD-FMK, Z-LEHD-FMK, or Z-IETD-FMK. Further preclinical studies were conducted in the MRL/lpr−/− murine model of ALPS. Forty five, 8-week old female MRL/lpr−/− mice were treated with 30 or 60 mg/kg of HCQ by gavage in sterile PBS or PBS alone three days per week for up to 14 weeks. Reductions of the spleen weight (p = 0.045, 437±85 vs 240±27) and cellularity (p = 0.08, 217±32 vs 148±18) were observed in high dose HCQ treated mice compared to controls at 7 weeks. Reductions in cellularity were also noted in the lymph nodes (p = 0.032, 118±33 vs 38±6). There was a trend towards decreasing DNT percentages in the spleen (21±5 vs 14±2), LN (70±4 vs 67±2) and blood (57±6 vs 51±5). Additionally, the CBC showed only marginal reductions in the WBC count (4.2±0.5 vs 3.5±0.3), hematocrit (49±0.3 vs 46±1.0), polymorphonuclear cells (33±3.7 vs 29±3.5) and monocytes (23±3.2 vs 17±2.5). Future studies are planned to more clearly determine the effect of HCQ on autoimmune kidney disease. Based on our in vitro and in vivo data, HCQ is effective at reducing lymphoproliferative activity in Fas deficient MRL/lpr−/− mice. It is being further explored in early phase clinical trials as a lympholytic agent to shrink lymph nodes and abrogate hypersplenism in ALPS patients. HCQ may also prove beneficial for long term use, especially in children, as a steroid sparing agent for treating refractory autoimmune cytopenias in ALPS.

scholarly journals TNF-α Triggers RIP1/FADD/Caspase-8-Mediated Apoptosis of Astrocytes and RIP3/MLKL-Mediated Necroptosis of Neurons Induced by Angiostrongylus cantonensis Infection

2021 ◽  
Author(s):  
Hongli Zhou ◽  
Minyu Zhou ◽  
Yue Hu ◽  
Yanin Limpanon ◽  
Yubin Ma ◽  
...  
Keyword(s):  
Cell Death ◽  
Enrichment Analysis ◽  
Angiostrongylus Cantonensis ◽  
Gene Set Enrichment Analysis ◽  
Caspase 8 ◽  
Cns Injury ◽  
Vitro Assay ◽  
Tnf Α

AbstractAngiostrongylus cantonensis (AC) can cause severe eosinophilic meningitis or encephalitis in non-permissive hosts accompanied by apoptosis and necroptosis of brain cells. However, the explicit underlying molecular basis of apoptosis and necroptosis upon AC infection has not yet been elucidated. To determine the specific pathways of apoptosis and necroptosis upon AC infection, gene set enrichment analysis (GSEA) and protein–protein interaction (PPI) analysis for gene expression microarray (accession number: GSE159486) of mouse brain infected by AC revealed that TNF-α likely played a central role in the apoptosis and necroptosis in the context of AC infection, which was further confirmed via an in vivo rescue assay after treating with TNF-α inhibitor. The signalling axes involved in apoptosis and necroptosis were investigated via immunoprecipitation and immunoblotting. Immunofluorescence was used to identify the specific cells that underwent apoptosis or necroptosis. The results showed that TNF-α induced apoptosis of astrocytes through the RIP1/FADD/Caspase-8 axis and induced necroptosis of neurons by the RIP3/MLKL signalling pathway. In addition, in vitro assay revealed that TNF-α secretion by microglia increased upon LSA stimulation and caused necroptosis of neurons. The present study provided the first evidence that TNF-α was secreted by microglia stimulated by AC infection, which caused cell death via parallel pathways of astrocyte apoptosis (mediated by the RIP1/FADD/caspase-8 axis) and neuron necroptosis (driven by the RIP3/MLKL complex). Our research comprehensively elucidated the mechanism of cell death after AC infection and provided new insight into targeting TNF-α signalling as a therapeutic strategy for CNS injury.

scholarly journals Antimalarial Activity of the Anticancer Histone Deacetylase Inhibitor SB939

2012 ◽  
Vol 56 (7) ◽  
pp. 3849-3856 ◽  
Author(s):  
Subathdrage D. M. Sumanadasa ◽  
Christopher D. Goodman ◽  
Andrew J. Lucke ◽  
Tina Skinner-Adams ◽  
Ishani Sahama ◽  
...  
Keyword(s):  
Cerebral Malaria ◽  
Histone Deacetylase ◽  
Hdac Inhibitor ◽  
Antimalarial Activity ◽  
Hdac Inhibitors ◽  
Parasite Life Cycle ◽  
Nonhistone Proteins ◽  
Content Type

ABSTRACTHistone deacetylase (HDAC) enzymes posttranslationally modify lysines on histone and nonhistone proteins and play crucial roles in epigenetic regulation and other important cellular processes. HDAC inhibitors (e.g., suberoylanilide hydroxamic acid [SAHA; also known as vorinostat]) are used clinically to treat some cancers and are under investigation for use against many other diseases. Development of new HDAC inhibitors for noncancer indications has the potential to be accelerated by piggybacking onto cancer studies, as several HDAC inhibitors have undergone or are undergoing clinical trials. One such compound, SB939, is a new orally active hydroxamate-based HDAC inhibitor with an improved pharmacokinetic profile compared to that of SAHA. In this study, thein vitroandin vivoantiplasmodial activities of SB939 were investigated. SB939 was found to be a potent inhibitor of the growth ofPlasmodium falciparumasexual-stage parasitesin vitro(50% inhibitory concentration [IC50], 100 to 200 nM), causing hyperacetylation of parasite histone and nonhistone proteins. In combination with the aspartic protease inhibitor lopinavir, SB939 displayed additive activity. SB939 also potently inhibited thein vitrogrowth of exoerythrocytic-stagePlasmodiumparasites in liver cells (IC50, ∼150 nM), suggesting that inhibitor targeting to multiple malaria parasite life cycle stages may be possible. In an experimentalin vivomurine model of cerebral malaria, orally administered SB939 significantly inhibitedP. bergheiANKA parasite growth, preventing development of cerebral malaria-like symptoms. These results identify SB939 as a potent new antimalarial HDAC inhibitor and underscore the potential of investigating next-generation anticancer HDAC inhibitors as prospective new drug leads for treatment of malaria.

Potent Induction of Human γ Globin Gene Expression by Largazole, a New Histone Deacetylase Inhibitor.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2022-2022
Author(s):  
Hua Cao ◽  
Rui Gao Fei ◽  
Albert A. Bowers ◽  
Thomas J. Greshock ◽  
Tenaya Newkirt ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Histone Deacetylase ◽  
Hdac Inhibitor ◽  
Globin Gene ◽  
Control Level ◽  
Hdac Inhibitors ◽  
Fetal Hemoglobin ◽  
Vitro Effect

Abstract Abstract 2022 Poster Board I-1044 Previous studies have demonstrated that Histone Deacetylase (HDAC) inhibitors such as butyrate and several short chain fatty acids, can induce fetal hemoglobin in humans and animal models; however induction of Hb F is achieved in relatively high concentrations of these compounds. We have previously investigated the induction of human γ globin gene activity by the prototypical HDAC inhibitor, FK228. The results demonstrated that FK228 is a more potent γ globin gene inducer compared to other HDAC inhibitors we have tested before (Am J Hematol. 12:981). In this study, we investigated the induction of human γ globin gene function of largazole and it's thiol analogue in vitro in cultures of normal human adult BFUe and in vivo in the mice carrying a human γ globin transgene. Largazole is a HDAC inhibitor which was recently isolated from a marine vyanobacterium by Luesch and co-workers. Structural features of largazole, a macrocyclic depsopeptide, closely resemble those of FK228, FR901375 and spiruchostatin. We have reported that largazole and numerous synthetic analogues are highly potent Class I histone deacetylase inhibitors (J Am Chem Soc. 130:11219, J Am Chem Soc. 2009 Feb 4). We used flow cytometry to measure the in vitro effect of largazole and it's derivatives on the frequency of HbF-positive erythroblasts in BFUe cultures from normal individuals; real-time quantitative PCR (RT-qPCR) and high performance liquid chromatography (HPLC) were used to measure the in vivo effects of largazole on human γ globin induction in γ transgenic mice carrying a human γ globin gene.. Our results show that largazole and it's thiol derivative are potent γ hemoglobin gene inducers. In the human BFUe cultures, largazole increased the levels of fetal hemoglobin positive cells from 21.9% (control level) to 62.8% at a concentration of 0.1μM; largazole thiol increased the levels of fetal hemoglobin positive cells to 62.0% at a concentration of 1μM. Transgenic mice carrying the human μLCR Aγ construct continue to express the human γ gene in the adult stage (Blood. 77:1326). Largazole was administered through IP injection at the dosages of 0.3mg/kg/day and 0.6mg/kg/day, 5 days per week, for 2 weeks to two cohorts of transgenic mice. Largazole at the dose of 0.3mg/kg/day increased the level of human γ mRNA at the end of injection by 160.7%; at a dose of 0.6mg/kg/day human γ mRNA increased by 174.7%. At the 0.6mg/kg/day dosage the level of fetal hemoglobin in the peripheral blood of the animals increased by 3.4 and 3.2 fold at day 21 and day 28, respectively. These results provide strong in vitro and in vivo evidence that Largazole and it's thiol analogue are potent HbF inducers acting at low concentrations, and thus provide promising alternatives to compounds currently considered for induction of Hb F in patients with sickle cell disease and thalassemia. Disclosures: No relevant conflicts of interest to declare.

Somatic Fas Mutations Account for Nearly One Third of Autoimmune Lymphoproliferative Syndrome (ALPS) Cases with Previously Unknown Genetic Mutations.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 710-710
Author(s):  
Kennichi Dowdell ◽  
Julie Niemela ◽  
Susan Price ◽  
Joie Davis ◽  
Katie Perkins ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Late Onset ◽  
Clinical Phenotype ◽  
Lymphocyte Apoptosis ◽  
Type Iii ◽  
Type Ia ◽  
Lymphoproliferative Syndrome ◽  
Autoimmune Cytopenias ◽  
Age Range

Abstract Abstract 710 Background: Autoimmune lymphoproliferative syndrome (ALPS) is characterized by childhood onset of lymphadenopathy, hepatosplenomegaly, autoimmune cytopenias, elevated (>1%) double negative T (DNT; CD3+, TCRalpha-beta+, CD4−, CD8−, B220+) lymphocytes in peripheral blood and an increased risk of lymphoma; primarily due to impaired lymphocyte apoptosis. Most cases (65%; 173 individuals in our cohort), known as ALPS Type Ia, are associated with dominant heterozygous germline mutations in the gene TNFRSF6 encoding the protein for CD95 (Fas, Apo-1). Another 5% of patients have mutations in FasL (Type Ib), caspases (Type II) or NRAS (Type IV). However, approximately 30% of ALPS patients in our cohort have no mutation found upon genomic sequencing of DNA from peripheral blood. We designated these patients as ALPS Type III (16%) if they met all the criteria of ALPS, i.e., elevated DNT cell numbers, nonmalignant chronic lymphadenopathy/splenomegaly and defective lymphocyte apoptosis by in vitro assay; we called them ALPS phenotype (14%) if they had all the features as described above but did not demonstrate an in vitro apoptosis defect. Holzelova et. al. (NEJM 2004; 351:1409) previously identified somatic Fas mutations in DNT cell population in 6 patients with ALPS phenotype. However, there was no information as to the proportion of ALPS patients expressing a somatic Fas mutation or any differences in their clinical phenotype. Methods and Results: Over the last 5 years we sought to determine the proportion of ALPS Type III and ALPS phenotype patients with somatic Fas mutations in their DNT cell population and to further clinically characterize these patients. DNT cells were purified to >50% by magnetic bead separation and DNA was sequenced for Fas. We found somatic Fas mutations in the DNT cells of 11/31 (35.5%) patients; 5/15 with ALPS Type III (5 males; age range = 1-17 years; median = 12 years), and 6/16 with ALPS phenotype (3 males and 3 females; age range = 3 mo–48 years; median age = 1 year). All the mutations clustered to an approximately 150 base region of the intracellular domain of Fas (exons 7, 8 and 9), except for one mutation in exon 3. All mutations resulted in functional loss of normal Fas signaling based on the mutation type or having been previously observed in ALPS Typa Ia. The somatic ALPS patients showed a similar clinical phenotype to that of ALPS Type Ia with increased DNT cell numbers (Median 6%; Range 4-19%), and increased levels of biomarkers like serum vitamin B12, IL-10 and sFasL. All 4 patients with onset of symptoms in infancy have required long-term treatment of their refractory autoimmune cytopenias with mycophenolate mofetil for the last 2-8years, while one of them underwent splenectomy. Inability to demonstrate defective lymphocyte apoptosis by in vitro testing of unseparated lymphocytes in ALPS phenotype patients with somatic Fas mutations is likely due to the relatively small number of affected cells (<20%) in their peripheral blood. Additionally, we hypothesize that the late onset of clinical disease in ALPS Type III patients with somatic Fas mutations may reflect the time required to accumulate a threshold number of cells that are able to confer clinical manifestations. Conclusion: Thus, the majority of somatic ALPS mutations can be detected by sequencing exons 7-9 of isolated DNT cell DNA. Patients with somatic Fas mutations now comprise the second largest group of known genetic mutations in ALPS, followed by patients with caspase 10, NRAS, caspase 8 and FasL germline mutations, respectively. We recommend testing for somatic Fas mutations in ALPS Type III patients (particularly those with late onset) and all ALPS phenotype patients, using ungated DNT purities of >50%. These data also highlight the role of somatic mutations in the pathogenesis of nonmalignant hematological conditions in adults and children, as well as in clonal malignancies. Disclosures: No relevant conflicts of interest to declare.

The mTOR Inhibitor Everolimus Overcomes CXCR4-Mediated Resistance to HDAC Inhibitor Panobinostat through Inhibition of p21 and Mitosis Regulators, Sensitizing MM Cells to DNA-Damaged Induced Apoptosis

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 891-891
Author(s):  
Katia Beider ◽  
Valeria Voevoda ◽  
Hanna Bitner ◽  
Evgenia Rosenberg ◽  
Hila Magen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Dna Repair ◽  
Cell Lines ◽  
Hdac Inhibitor ◽  
Mtor Inhibitor ◽  
Mtor Inhibition ◽  
Induced Apoptosis

Abstract Introduction: Multiple myeloma (MM) is a neoplastic disorder that is characterized by clonal proliferation of plasma cells in the bone marrow (BM). Despite the initial efficacious treatment, MM patients often become refractory to common anti-MM drugs, therefore novel therapies are in need. Pan-histone deacetylase (HDAC) inhibitor panobinostat exerts multiple cytotoxic actions in MM cells in vitro, and was approved for the treatment of relapsed/refractory MM in combination with bortezomib and dexamethasone. Although having promising anti-MM properties, panobinostat lacks therapeutic activity as monotherapy. The aim of the current study was to elucidate the mechanisms underlying MM resistance to panobinostat and to define strategies to overcome it. Results: Panobinostat at the low concentrations (IC50 5-30 nM) suppressed the viability in MM cell lines (n=7) and primary CD138+ cells from MM patients (n=8) in vitro. Sensitivity to panobinostat correlated with reduced expression of chemokine receptor CXCR4, while overexpression of CXCR4 or its ligand CXCL12 in RPMI8226 and CAG MM cell lines significantly (p<0.001) increased their resistance to panobinostat, pointing to the role of the CXCR4 axis in HDACi response. Notably, similar expression levels of class I HDACs (HDAC1-3) were detected in MM cells with either low or high CXCR4. Interaction with BM stromal cells that represent the source of CXCL12 also protected MM cells from panobinostat-induced apoptosis, further strengthening a role for CXCR4 downstream pathway. Decreased sensitivity to cytotoxic effect was concomitant with reduced histone (H3K9 and H4K8) acetylation in response to panobinostat treatment. In addition, resistance to HDACi was associated with the reversible G0/G1 cell growth arrest, whereas sensitivity was characterized by apoptotic cell death. Analysis of intra-cellular signaling mediators involved in CXCR4-mediated HDACi resistance revealed the pro-survival AKT/mTOR pathway to be regulated by both CXCR4 over-expression and interaction with BMSCs. Combining panobinostat with mTOR inhibitor everolimus abrogated the resistance and induced synergistic cell death of MM cell lines and primary MM cells, but not of normal mononuclear cells (CI<0.4). This effect was concurrent with the increase in DNA double strand breaks, histone H2AX phosphorylation, loss of Dψm, cytochrome c release, caspase 3 activation and PARP cleavage. The increase in DNA damage upon combinational treatment was not secondary to the apoptotic DNA fragmentation, as it occurred similarly when apoptosis onset was blocked by caspase inhibitor z-VAD-fmk. Kinetics studies also confirmed that panobinostat-induced DNA damage preceded apoptosis induction. Strikingly, combined panobinostat/everolimus treatment resulted in sustained DNA damage and irreversible suppression of MM cell proliferation accompanied by robust apoptosis, in contrast to the modest effects induced by single agent. Gene expression analysis revealed distinct genetic profiles of single versus combined exposures. Whereas panobinostat increased the expression of cell cycle inhibitors GADD45G and p21, co-treatment with everolimus abrogated the increase in p21 and synergistically downregulated DNA repair genes, including RAD21, Ku70, Ku80 and DNA-PKcs. Furthermore, combined treatment markedly decreased both mRNA and protein expression of anti-apoptotic factors survivin and BCL-XL, checkpoint regulator CHK1, and G2/M-specific factors PLK1, CDK1 and cyclin B1, therefore suppressing the DNA damage repair and inhibiting mitotic progression. Given the anti-apoptotic role of p21, the synergistic lethal effect of everolimus could be attributed to its ability to suppress p21 induction by panobinostat ensuing the shift in the DNA damage response toward apoptosis. Conclusions: Collectively, our findings indicate that CXCR4/CXCL12 activity promotes the resistance of MM cells to HDACi with panobinostat through mTOR activation. Inhibition of mTOR by everolimus synergizes with panobinostat by simultaneous suppression of p21, G2/M mitotic factors and DNA repair machinery, rendering MM cells incapable of repairing accumulated DNA damage and promoting their apoptosis. Our results unravel the mechanism responsible for strong synergistic anti-MM activity of dual HDAC and mTOR inhibition and provide the rationale for a novel therapeutic strategy to eradicate MM. Disclosures No relevant conflicts of interest to declare.

R412 – Role of KITENIN in Progression and Metastasis of SCC

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P181-P181
Author(s):  
Mark Zarrella ◽  
Joon Kyoo Lee MD ◽  
Sang-Chul Lim
Keyword(s):  
Squamous Cell Carcinoma ◽  
Lymph Nodes ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Vitro Assay ◽  
Transfected Cells ◽  
Metastatic Lymph Nodes ◽  
Metastatic Lymph

Problem The expression of KAI1 (a metastatic suppressor gene) in cancer cells results in reduced cell motility and invasiveness. A cDNA clone of VANGL1, a member of the tetraspanin protein family that specifically interacts with the COOH-terminal cytoplasm domain of KAI1, was isolated and renamed KITENIN (KAI1 COOH-terminal interacting tetraspanin). The purpose of this study was to investigate the role of KITENIN on the progression and metastasis of transfected squamous cell carcinoma using in vivo and in vitro experiments. Methods Locally advanced squamous cell carcinoma tissues from five patients were obtained for investigation of KITENIN expression. Malignant tumors, normal adjacent mucosa tissues, metastatic lymph nodes, and non-metastatic lymph nodes were collected. KITENIN or vector only (control) was transfected into SCC (squamous cell carcinoma) VII, a mouse squamous cell carcinoma cell line, using FuGENE 6. An in vitro assay (invasion, migration, and proliferation) for KITENIN and the vector-transfected group was studied. The KITENIN or vector-transfected SCC VII cells were injected subcutaneously into 12 C3H/HeJ syngeneic mice (6 mice for each group). The tumor size was measured daily for 4 weeks. During the fifth week after injection, the presence of metastasis in the lung and liver tissue was evaluated for each mouse with a tumor mass on the back; the tissues were assessed by gross and microscopic examination. Results KITENIN was highly expressed in tumors and metastatic lymph nodes from patients. KITENIN-transfected cells showed significantly increased invasion, migration, and proliferation compared with the vector-transfected cells. Tumor volume was more increased in the KITENIN-transfected cells-injected mice. Lung metastasis was found in the KITENIN-group (3/6 mice), while no metastasis in the vector-group. Conclusion KITENIN participates in the progression and metastasis of SCC. Significance An antisense KITENIN strategy may be a useful method to inhibit progression and metastasis in squamous cell carcinoma. Support This study was financially supported by Chonnam National University, 2006.

scholarly journals HDAC inhibitor valproic acid upregulates CAR in vitro and in vivo

2007 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
Blanca Segura-Pacheco ◽  
Berenice Avalos ◽  
Edgar Rangel ◽  
Dora Velazquez ◽  
Gustavo Cabrera
Keyword(s):  
Valproic Acid ◽  
Hdac Inhibitor
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