To identify credible causal risk variants (CCVs) associated with different histotypes of epithelial ovarian cancer (EOC), we performed genome-wide association analysis for 470,825 genotyped and ...10,163,797 imputed SNPs in 25,981 EOC cases and 105,724 controls of European origin. We identified five histotype-specific EOC risk regions (p value <5 × 10−8) and confirmed previously reported associations for 27 risk regions. Conditional analyses identified an additional 11 signals independent of the primary signal at six risk regions (p value <10−5). Fine mapping identified 4,008 CCVs in these regions, of which 1,452 CCVs were located in ovarian cancer-related chromatin marks with significant enrichment in active enhancers, active promoters, and active regions for CCVs from each EOC histotype. Transcriptome-wide association and colocalization analyses across histotypes using tissue-specific and cross-tissue datasets identified 86 candidate susceptibility genes in known EOC risk regions and 32 genes in 23 additional genomic regions that may represent novel EOC risk loci (false discovery rate <0.05). Finally, by integrating genome-wide HiChIP interactome analysis with transcriptome-wide association study (TWAS), variant effect predictor, transcription factor ChIP-seq, and motifbreakR data, we identified candidate gene-CCV interactions at each locus. This included risk loci where TWAS identified one or more candidate susceptibility genes (e.g., HOXD-AS2, HOXD8, and HOXD3 at 2q31) and other loci where no candidate gene was identified (e.g., MYC and PVT1 at 8q24) by TWAS. In summary, this study describes a functional framework and provides a greater understanding of the biological significance of risk alleles and candidate gene targets at EOC susceptibility loci identified by a genome-wide association study.
We discovered five risk regions specific to ovarian cancer subtypes by performing a genome-wide association study involving 26,000 ovarian cancer cases and 105,000 controls. We located 4,008 credible causal variants in ovarian cancer active promoters and enhancers. We also identified susceptibility genes and explored gene-variant interactions.
Cyclin-dependent kinases (CDKs) are regulatory proteins of the eukaryotic cell cycle. They act after association with different cyclins, the concentrations of which vary throughout the progression of ...the cell cycle. As central mediators of cell growth, CDKs are potential targets for inhibitory molecules that would allow disruption of the cell cycle in order to evoke an antiproliferative effect and may therefore be useful as cancer therapeutics. We synthesized several inhibitory 2,6,9-trisubstituted purine derivatives and solved the crystal structure of one of these compounds, H717, in complex with human CDK2 at 2.6 Å resolution. The orientation of the C 2-p-diaminocyclohexyl portion of the inhibitor is strikingly different from those of similar moieties in other related inhibitor complexes. The N 9-cyclopentyl ring fully occupies a space in the enzyme which is otherwise empty, while the C 6-N-aminobenzyl substituent points out of the ATP-binding site. The structure provides a basis for the further development of more potent inhibitory drugs.
A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and ...73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10(-20)), ER-negative BC (P=1.1 × 10(-13)), BRCA1-associated BC (P=7.7 × 10(-16)) and triple negative BC (P-diff=2 × 10(-5)). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10(-3)) and ABHD8 (P<2 × 10(-3)). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3'-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk.
Smooth muscle cell (SMC) proliferation is a critical component of neointimal formation in many models of vascular injury and in human lesions as well. Cell-cycle inhibition by gene transfer ...techniques can block SMC proliferation and lesion formation in animal models, although these methods are not yet applicable to the treatment of human disease. Flavopiridol is a recently identified, potent, orally available cyclin-dependent kinase inhibitor.
Using human aortic SMCs, we found that flavopiridol in concentrations as low as 75 nmol/L resulted in nearly complete inhibition of basic fibroblast growth factor-induced and thrombin-induced proliferation. At this dose, flavopiridol inhibited cyclin-dependent kinase activity, as measured by histone H1 phosphorylation, but had no effect on mitogen-activated protein kinase activation. Induction of the cell cycle-related proteins cyclin D1, proliferating cell nuclear antigen, and phosphorylated retinoblastoma protein was also blocked by flavopiridol. Flavopiridol had no effect on cellular viability. To test whether flavopiridol had a similar activity in vivo when administered orally, we examined neointimal formation in rat carotid arteries after balloon injury. Flavopiridol 5 mg/kg reduced neointimal area by 35% and 39% at 7 and 14 days, respectively, after injury.
Flavopiridol inhibits SMC growth in vitro and in vivo. Its oral availability and selectivity for cyclin-dependent kinases make it a potential therapeutic tool in the treatment of SMC-rich vascular lesions.
A novel drug delivery platform has been developed that utilizes a naturally occurring receptor known as the neonatal Fc receptor (FcRn). The receptor is specific for the Fc fragment of IgG and is ...expressed in epithelial cells where it functions to transport immunoglobulins across these cell barriers. It has been shown that FcRn is expressed in both the upper and central airways in non-human primates as well as in humans. Pulmonary delivery of an erythropoietin- Fc fusion molecule (EpoFc) was previously demonstrated in non-human primates using this FcRn pathway. We have now conducted a phase I clinical study to test whether the FcRn pathway functioned similarly in man using human erythropoietin (Epo) fused to the Fc portion of human IgG1. The design was a three leg, non-randomized study conducted in healthy male volunteers with rising doses (3, 10, and 30 microg/kg) of the fusion protein targeted to the central lung regions. Using a target range of 10-30% vital capacity and 15 breaths per minute, approximately 70% of the lung-deposited dose of aerosolized EpoFc was delivered safely and effectively to the central lung regions. We showed dose-dependent concentrations of the fusion protein in the serum and an increase in circulating reticulocytes was evident in the highest dose group, thus demonstrating that large therapeutic molecules can be delivered to humans via the lung, with retention of biological activity, using the FcRn-mediated transport pathway.
Prophylaxis with factor VIII (FVIII) in patients with severe hemophilia A requires frequent intravenous injections (3–4 per week), impacting compliance and outcomes. A long-lasting recombinant FVIII ...Fc fusion protein (rFVIIIFc) was developed to reduce the frequency of injections. The pharmacokinetics (PK), safety, and efficacy of rFVIIIFc were evaluated in the phase 3 A-LONG study and the primary results were reported recently (Mahlangu J, J Thromb Haemost 2013). To illustrate differences in dosing regimens and clinical outcomes with rFVIIIFc and currently available FVIII products, we compared the prestudy and on-study dose, dose interval, and bleeding rates for subjects in A-LONG who reported receiving a prophylactic regimen with any FVIII product prior to study entry. We also used population PK models to estimate trough FVIII levels on various dosing regimens of rFVIIIFc and rFVIII (Advate®).
Previously treated male patients who were ≥12 years old with severe hemophilia A were enrolled in A-LONG and assigned to 1 of 3 treatment arms: Arm 1, individualized prophylaxis with PK-driven dose and dose interval adjustments (25–65 IU/kg every 3–5 days); Arm 2, once weekly prophylaxis (65 IU/kg); and Arm 3, episodic treatment (10–50 IU/kg) for bleeding episodes. A 2-compartmental population PK model of rFVIIIFc was developed based on activity-time profiles in 180 severe hemophilia A subjects aged 12-65 years old (16 from a phase 1/2a study and 164 from A-LONG collected over ≤ 52 weeks of treatment). A 2-compartment population PK model of Advate® was developed based on the single-dose PK profiles from 16 subjects in the phase 1/2a study and 30 subjects in the sequential PK subgroup in A-LONG. The population PK estimates for Advate® and rFVIIIFc from A-LONG were used for dosing simulations. We identified Arm 1 subjects who reported use of a prophylactic regimen at least 2 times a week with any FVIII product prior to study entry and compared their dosing regimens and bleeding rate in the 12 months prior to study with their rFVIIIFc dosing regimens and annualized bleed rate (ABR) on study. Only subjects on study for ≥ 6 months were included. The median ABR, dose, and dose interval during the last 3 months on study were analyzed.
Of 165 total patients, 118 were in Arm 1, of whom 80 received a prophylactic regimen at least 2 times a week prestudy and were in the study for ≥ 6 months. Subjects were grouped by prestudy dosing interval. The table below provides prestudy and on study dose, dose interval, and bleeding rates for these groups.
The majority of patients (65/80) reported a dosing interval of 3 times a week, with the most common dose of 25 IU/kg FVIII, and a median of 5.5 bleeding events 12 months prior to study entry. At the end of the study, these same patients were receiving ∼40 IU/kg rFVIIIFc twice a week (every 3.5 days) with a median ABR of 0. Population PK simulation indicated that 76.1% of patients treated with 40 IU/kg of rFVIIIFc twice a week would maintain FVIII levels above 1% at all times. In contrast, population PK simulation indicated that 42.3% of patients treated with 25 IU/kg of Advate® 3 times a week would maintain FVIII levels above 1% at all times. Overall, rFVIIIFc was well tolerated and no inhibitor development was detected during the A-LONG study.
The results from this descriptive analysis of dose, dose interval, and bleeding rates for subjects with severe hemophilia A who were on prophylaxis suggest that switching from current FVIII products to a rFVIIIFc regimen may allow for less frequent dosing to maintain FVIII activity >1%.
Shapiro:Baxter: Consultancy, Global steering committees Other, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer: Global steering committees, Global steering committees Other, Membership on an entity's Board of Directors or advisory committees, Research Funding; Inspiration: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Research Funding; Biogen Idec: Research Funding. Ragni:Biogen Idec: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Smith Kline Glaxo: Consultancy, Research Funding; Tacere Benitec: Consultancy; Baxter: Research Funding; Bayer: Research Funding; CSL Behring: Research Funding; Merck: Research Funding; Novo Nordisk: Research Funding; Pfizer: Research Funding. Kulkarni:Biogen Idec, Novo Nordisk, Baxter : Membership on an entity's Board of Directors or advisory committees. Kulke:Biogen Idec: Employment. Potts:Biogen Idec: Employment. Neelakantan:Biogen Idec: Employment. Nestorov:Biogen Idec: Employment. Dumont:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Jiang:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Brennan:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Pierce:Biogen Idec: Employment, Equity Ownership.
Phorbol esters which activate protein kinase C (PKC) have been shown to enhance experimental lung metastasis. Therefore, it was reasoned that inhibitors of PKC might also modulate metastasis. We have ...investigated this possibility using a PKC inhibitor, MDL 27,032 4-propyl-5(4-pyridinyl)-2(3H)-oxazolone, as well as staurosporine and H-7. Treatment of B16F1 murine melanoma cells with MDL 27,032 for 24 h in culture and subsequent i.v. injection of the cells into mice resulted in greater than 90% inhibition of lung metastasis. Inhibition of metastasis was time dependent, with 90% of maximum inhibition occurring by 8 h of incubation. The 50% inhibitory concentration (IC50) for inhibition of metastasis with MDL 27,032 was 7 microM, a value similar to that for the inhibition of B16F1 membrane-associated PKC (IC50 = 13 microM) but not cytosolic PKC (IC50 = 54 microM). B16F1 cells treated with MDL 27,032 for 24 h were less adherent than untreated cells to extracellular matrix/basement membrane proteins. Adhesion to fibrinogen and collagen IV was inhibited (IC50 = 6 microM and 48 microM, respectively) by MDL 27,032, whereas adherence to laminin and fibronectin was not affected, indicating that the drug affects specific adhesion molecules. MDL 27,032-treated cells were also found to be less adherent than untreated cells to human umbilical vein endothelial cells. The phosphorylation of an 80-kDa B16F1 cell plasma membrane protein was stimulated under conditions known to stimulate PKC activity, and MDL 27,032 inhibited this phosphorylation in a dose-dependent manner. MDL 27,032 was more potent than H-7 for the inhibition of metastasis but was significantly less potent than staurosporine. These results support the hypothesis that there is a critical role for PKC-mediated phosphorylation of cell surface adhesion receptors in metastasis.
(E)-2'-Deoxy-2'-(fluoromethylene)cytidine (MDL 101,731) is a mechanism-based inhibitor of ribonucleoside diphosphate reductase (J. Stubbe, personal communication), an enzyme involved in DNA synthesis ...and therefore a potential target for cancer chemotherapy. In the present report, we show that MDL 101,731 inhibits the proliferation of several human breast cancer cell lines, including the estrogen-dependent cell line, MCF-7, and the estrogen-independent cell lines MDA-MB-231, MDA-MB-468, and MDA-MB-435 in vitro at nanomolar concentrations (50% inhibitory concentration, 15-26 nM). Administration of MDL 101,731 caused marked regression of tumors which formed after s.c. inoculation of all four of the cell lines in athymic (nude) mice. MDA-MB-231 tumors were found to be most sensitive to MDL 101,731 with a 90-100% cure rate at doses of MDL 101,731 between 2 and 20 mg/kg, given as once daily i.p. injections, 5 days/week for as little as 3 weeks. Almost complete cessation of MDA-MB-231 tumor growth was obtained with a dose of 0.5 mg/kg MDL 101,731 following the same dosing regimen. MDA-MB-468, MDA-MB-435, and MCF-7 tumors were not as sensitive as MDA-MB-231, but tumor regression of 50, 65, and 80%, respectively, was obtained after 5-6 weeks of treatment. The effects of MDL 101,731 on spontaneous metastasis of MDA-MB-435 cells from the mammary fat pad to the lung was also examined, and it was found that the number of lung metastases was significantly decreased if mice received MDL 101,731 while the primary tumors were growing and after primary tumors were surgically excised. Additionally, preliminary evidence raises the possibility that MDL 101,731 may induce apoptosis in MDA-MB-231 tumors. Our data suggest that the use of MDL 101,731 for the treatment of breast cancer and possibly other solid tumors should be pursued.
Abstract 545
A recombinant B-domain-deleted factor VIII-Fc (rFVIIIFc) fusion protein was created as an approach to extend the half-life of FVIII. The pharmacokinetics and pharmacodynamics of rFVIIIFc ...were evaluated in the Chapel Hill colony of hemophilia A dogs. These dogs have a severe hemophilic phenotype comparable to the severe form of human disease with F.VIII < 1%. A single intravenous dose (125 IU/kg) was administered to four dogs and immediately corrected the clotting to normal as measured by whole blood clotting time (WBCT) and aPTT. The WBCT remained below 20 min, the time consistent with FVIII:C > 1%, through approximately 96 h. The range of WBCT in our normal dogs is 8 to 12 min. The concentration of rFVIIIFc in the plasma was measured by ELISA and the terminal half-life was 15.7 ± 1.7 hr. Similar results were obtained when rFVIIIFc was measured using a FVIII-specific chromogenic activity assay (half-life was 15.4 ± 0.3 hr). The concentration vs. time curves were similar using both methods. The activity data were converted to ng/mL using the specific activity of the test article that was used to dose the animals, and these data correlated well with the ELISA data, thus demonstrating that the protein that was measured by ELISA was fully active.
Two of the dogs also received a single dose of recombinant B-domain deleted FVIII (rBDD-FVIII, ReFacto®), 114 IU/kg for one dog and 120 IU/kg rBDD-FVIII for the other, and then received rFVIIIFc (125 IU/kg) 72 hr later in a cross over design. Clotting was corrected to normal immediately after dosing with both rBDD-FVIII and rFVIIIFc (determined by WBCT and clotting activity measured using an aPTT assay). However, the WBCT normalization after rFVIIIFc lasted for approximately twice as long compared to rBDD-FVIII and the half-lives determined from the ELISA data for FVIIIFc (15.7 ± 1.7 hr) were twice those determined for rBDD-FVIII (7.0 hr and 6.7 hr). No adverse clinical signs were detected with any of the infusions. Therefore construction of an Fc fusion of FVIII produces a molecule with a defined mechanism of action that has an increased half life and the potential to provide prolonged protection from bleeding.
Dumont:Biogen Idec (Syntonix Subsidiary): Employment. Kamphaus:Biogen Idec (Syntonix Subsidiary): Employment. Fraley:Biogen Idec/Syntonix Subsidiary: Employment. Ashworth:Biogen Idec (Syntonix Subsidiary): Employment. Bitonti:Biogen Idec/Syntonix Subsidiary: Employment.
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