Citations

We investigate the in vivo patterns of stem cell divisions in the human hematopoietic system throughout life. In particular, we analyze the shape of telomere length distributions underlying stem cell behavior within individuals. Our mathematical model shows that these distributions contain a fingerprint of the progressive telomere loss and the fraction of symmetric cell proliferations. Our predictions are tested against measured telomere length distributions in humans across all ages, collected from lymphocyte and granulocyte sorted telomere length data of 356 healthy individuals, including 47 cord blood and 28 bone marrow samples. We find an increasing stem cell pool during childhood and adolescence and an approximately maintained stem cell population in adults. Furthermore, our method is able to detect individual differences from a single tissue sample, i.e. a single snapshot. Prospectively, this allows us to compare cell proliferation between individuals and identify abnormal stem cell dynamics, which affects the risk of stem cell related diseases.

Objectives: The objectives of this paper are to compare in a multicenter setting patterns of regional cortical thickness in patients with relapsing–remitting multiple sclerosis (RRMS) and cognitive impairment (CI) and those cognitively preserved (CP), and explore the relationship between cortical thinning and cognitive performance. Methods: T1-weighted isotropic brain scans were collected at 3T from seven European centers in 60 RRMS patients and 65 healthy controls (HCs). Patients underwent clinical and neuropsychological examinations. Cortical thickness (CTh) measures were calculated using FreeSurfer (failing in four) and both lobar and vertex-based general linear model (GLM) analyses were compared between study groups. Results: Twenty (36%) MS patients were classified as CI. Mean global CTh was smaller in RRMS patients compared to HCs (left 2.43 vs. 2.53 mm, right 2.44 vs. 2.54 mm, p < 0.001). Multivariate GLM regional analysis showed significantly more temporal thinning in CI compared to CP patients. Verbal memory scores correlated to regional cortical thinning in the insula whereas visual memory scores correlated to parietal thinning. Conclusions: This multicenter study showed mild global cortical thinning in RRMS. The extent of thinning is less pronounced than previously reported. Only subtle regional differences between CI and CP patients were observed, some of which related to specific cognitive domains.

Abstract Purpose: Treatment of recurrent ovarian cancer is limited by low response rates to salvage chemotherapy. Novel small molecule inhibitors to Chk1 (checkpoint kinase 1) have been proposed to potentiate the cytotoxic effect of one such salvage treatment, gemcitabine, by interrupting the DNA damage repair pathway. Patient derived tumorgrafts were characterized by responsiveness to gemcitabine +/- MK8776 (Chk1 inhibitor). Response was correlated with markers of Chk1 activity. Methods: Patient-derived tumorgraft models were created from patients undergoing surgery for epithelial ovarian cancer. Gemcitabine response was characterized in five high-grade serous models (PH044, PH048, PH070, PH080, and PH110). Two models (PH048 and PH080) were treated with gemcitabine monotherapy (240 mg/kg qweek x 4 doses), MK8776 monotherapy (32 mg/kg qweek x 4 doses), and with combination therapy (Gemcitabine 190 mg/kg and MK8776 32 mg/kg qweek x 4 doses). Animals were monitored for cytotoxicity, and tumors were measured weekly with ultrasound. Response to gemcitabine and to combination therapy was correlated to immunohistochemistry of γH2AX and immunoblotting for p345-Chk1 and p296-Chk1. Results: Gemcitabine monotherapy did not affect tumor growth in two models (PH044 and PH048). Significant in vivo response to gemcitabine was seen in PH070 and PH080. Significant growth attenuation but not tumor regression was seen in PH110. MK8776 did not have any effect on tumor growth as monotherapy or in combination with gemcitabine in the gemcitabine resistant model, PH048. In contrast, in a gemcitabine sensitive model, PH080, MK8776 monotherapy significantly attenuated tumor growth, and there was a trend for MK8776 to potentiate the cytotoxic effects of gemcitabine in PH080 (p=0.16). Final tumor weights in the PH080 model after 4 doses of chemotherapy were 1.7 g (90%CI: 1.5-1.9g), 0.3g (90%CI: 0.18-0.35g), and 0.14g (90%CI: 0.08-.19g) in the control, gemcitabine alone, and gemcitabine with MK8776 groups respectively. Decrease in the tumor auto-phosphorylation of Chk1 at Serine-296 was observed in some, but not all models in response to MK8766 treatment. γH2AX increased in response to the addition of MK8776 to gemcitabine. Conclusions: Chk1 inhibition may enhance the activity of gemcitabine in some, but not all ovarian tumors. Further work is needed to find markers that will predict response to Chk1 inhibitors to help select patients for future clinical trials. While pChk1-S296 previously demonstrated potential utility as a biomarker of Chk1 inhibition, in vivo assessments of its differential expression may demonstrate the unreliability of this marker. This work supports the use of patient derived tumorgrafts in drug development for ovarian cancer. Citation Format: A Kumar, S Weroha, M Becker, X Hou, S Greiner, L Karnitz, P Haluska. Chk1 inhibitor (MK8776) enhances cytotoxicity of gemcitabine in select patient-derived ovarian tumorgraft models [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1419.

Abstract Patient derived xenografts (PDX) mouse models for many types of cancer have demonstrated therapeutic responses similar to those seen in patients. Thus, resected patient tumor tissue directly implanted into immune compromised mice followed by therapy and tumor growth analysis is thought to be the closest preclinical model to predict patient therapeutic responses. To date, few models are available for the different histotypes of thyroid cancer derived from follicular thyrocytes; these include papillary, follicular, Hurthle cell, squamous and anaplastic thyroid carcinoma. We have developed eight PDX models in athymic nude mice representing all of these subtypes. The models have been extensively characterized for mutational status (i.e. BRAF, telomerase, RAS, PTEN, TP53, RB, etc) as well as validation by short tandem repeat (STR) analysis to match that of the originating patient tumor tissue. Squamous and anaplastic thyroid cancers are rare tumor types with no FDA approved therapies. Each model demonstrated their own unique responses to radiation, cytotoxic or molecular targeted therapies such as doxorubicin, sorafenib (tyrosine kinase inhibitor), cisplatin, paclitaxel, sunitinib (tyrosine kinase inhibitor), erlotinib (EGFR inhibitor), trametinib (MEK inhibitor) and vemurafenib (BRAF inhibitor). We expect that these models may provide useful in vivo models for thyroid cancer research as well as models for therapeutic guidance based upon histotype, mutational status and response to therapies. Citation Format: Laura A. Marlow, Adam C. Mathias, Louis K. Dawson, William F. Durham, Kenneth A. Meshaw, Robert J. Mullin, Daniel L. Small, Aidan J. Synnott, Dragana Milosevic, Brian C. Netzel, Stefan K. Grebe, Kevin Wu, Robert C. Smallridge, John A. Copland. Characterization of novel thyroid PDX models and their response to combination therapies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1458. doi:10.1158/1538-7445.AM2015-1458

Abstract The success of clinical trials for patients with malignant melanoma (MM) designed from the “promising” results using pre-clinical models is minimal. With its increase in incidence, there is a dire need to develop both pre-clinical models comparable to clinical practice that have the capability to translate from bench-to-bedside and novel therapeutic agents for this life-threatening form of skin cancer. To address this concern, we have developed a panel of pre-clinical MM models including patient matched cell lines, patient cell-line derived xenograft models and patient tumor tissue-derived xenograft models. Patient derived xenograft (PDX) models are purported to most closely replicate a patient's response to therapy. Since the development of patient-derived cell lines and tumors grown in mice were more efficacious, their genetic, phenotypic, and therapeutic responses were compared to those of their corresponding patient-matched PDX model. Each model was molecularly characterized to confirm a match to that of the originating patient tumor tissue via protein immunohistochemistry (IHC), mRNA quantitative polymerase chain reaction (qPCR), DNA short tandem repeat (STR) analysis, and Sanger sequencing. Each pre-clinical model provided a genetic match to their respective patient tumor sample. All pre-clinical models were positive for the melanoma-specific markers (S-100 beta, HMB-45, and Melan-A) confirming a melanoma phenotype. Soft agar studies and tumor growth of our PDX and patient cell-line derived xenograft models confirmed tumorigenicity within our models providing the foundation to perform therapeutic studies. Mutation status data (i.e. BRAF, RAS), patient therapeutic clinical history and oncogene overexpression analysis (pERK, pAKT, PI3K, pmTOR, etc.) provide the platform and rationale behind the use of specific therapeutic agents per model. BRAF, NRAS and KRAS mutations were identified along with elevated pERK, pAKT and pmTOR in the models. Targeted therapies (trametinib/MEK inhibitor; vemurafenib/BRAF inhibitor; MK-2206/pAKT inhibitor; and everolimus/mTOR inhibitor) demonstrated dose dependent inhibition of cell proliferation in each of the models based upon oncogenic expression or mutations. In vivo experiments are in progress, which will allow comparison of the three models. The next steps include combination therapy to identify antitumor synergy targeting oncogenic signaling pathways. Citation Format: Antoneicka L. Harris, Laura Marlow, Adam Mathias, Louis Dawson, William Durham, Kenneth Meshaw, Robert Mullin, Daniel Small, Aidan Synnott, Kevin Wu, Dragana Milosevic, Brian Netzel, Stefan Grebe, Svetomir Markovic, John Copland. Characterization of novel patient derived melanoma xenografts and cell lines in response to targeted therapies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2417. doi:10.1158/1538-7445.AM2015-2417

BackgroundThe ability of von Willebrand factor (VWF) to bind platelet GP Ib and promote platelet plug formation is measured in vitro using the ristocetin cofactor (VWF:RCo) assay. Automated assay systems make testing more accessible for diagnosis, but do not necessarily improve sensitivity and accuracy.ObjectiveWe assessed the performance of a modified automated VWF:RCo assay protocol for the Behring Coagulation System (BCS®) compared to other available assay methods.MethodsResults from different VWF:RCo assays in a number of specialized commercial and research testing laboratories were compared using plasma samples with varying VWF:RCo activities (0–1.2 IU mL−1). Samples were prepared by mixing VWF concentrate or plasma standard into VWF‐depleted plasma. Commercially available lyophilized standard human plasma was also studied. Emphasis was put on the low measuring range. VWF:RCo accuracy was calculated based on the expected values, whereas precision was obtained from repeated measurements.ResultsIn the physiological concentration range, most of the automated tests resulted in acceptable accuracy, with varying reproducibility dependent on the method. However, several assays were inaccurate in the low measuring range. Only the modified BCS protocol showed acceptable accuracy over the entire measuring range with improved reproducibility.ConclusionsA modified BCS® VWF:RCo method can improve sensitivity and thus enhances the measuring range. Furthermore, the modified BCS® assay displayed good precision. This study indicates that the specific modifications − namely the combination of increased ristocetin concentration, reduced platelet content, VWF‐depleted plasma as on‐board diluent and a two‐curve calculation mode − reduces the issues seen with current VWF:RCo activity assays.

SUMMARYBackgroundClinical factors were previously identified as predictors of short‐term treatment efficacy in Crohn's disease (CD). The PRECiSE 3 (P3) 7‐year trial provides an opportunity to study predictors of short‐ and long‐term clinical remission among CD patients treated with certolizumab pegol (CZP).AimTo identify factors that influence long‐term remission of CD with CZP treatment.MethodsPatients who had completed placebo‐controlled studies (PRECiSE 1/PRECiSE 2, P1/P2) enrolled in P3 and received open‐label CZP 400 mg every 4 weeks up to 7 years. Baseline predictors included, but were not limited to, smoking status, disease duration, prior inflammatory bowel disease (IBD) surgery, Harvey–Bradshaw Index (HBI), albumin, haematocrit and CZP exposure; association with time to initial remission (HBI ≤4) was tested for patients who received CZP in P1/P2; time to loss of remission/frequency of maintenance of remission was also tested. Univariate analyses and multivariate Cox or logistic regression models were used.ResultsPredictors for initial remission (N = 377) included age, haematocrit, prior IBD surgery and entry HBI (P < 0.05 for all). Predictors for loss of remission (N = 437) included HBI, serum albumin concentration, haematocrit, smoking status and exposure. Predictors of maintenance of remission (N = 437) included haematocrit, IBD surgery, HBI, disease duration, serum albumin concentration and exposure. Significant predictors were confirmed with stepwise multivariate regression models.ConclusionsThese analyses identified several influential parameters for short‐and long‐term remission of Crohn's disease with certolizumab pegol treatment. The data yield valuable hypotheses regarding factors that influence certolizumab pegol treatment. More investigation is needed.(ClinicalTrials.gov identifier NCT00552058).

Abstract Intro: Male BC is a rare disease (&lt;1% male tumors); knowledge is limited and management extrapolated from female BC. An international consortium, coordinated by EORTC and TBCRC, was created to better characterize and manage this disease, with 3 parts: 1) retrospective joint analysis 2) prospective registry 3) clinical trial(s). We report 1st results of part 1. Methods: Joint analysis of male BC pts with available FU & FFPE samples, treated in 1990-2010, in 23 centers from 9 countries. Clinical data, long term outcomes, local pathology were centrally analyzed at EORTC. FFPE samples were analyzed at 3 central labs (UK, NL, US) for histology, grade, ER, PR, AR, HER-2, Ki67. Cut-off for positivity: Allred score ≥ 3 for ER/ AR/PR; 20% for Ki67; ASCO-CAP for HER2. Outcome data (OS & RFS) analyzed per Kaplan Meier, p-values correspond to logrank test, CI’s by Brookmeyer & Crowley. Reported % use number of non-missing values as denominator. Results: 1822 pts enrolled; 349 (19%) ineligible (no valid central lab assessment); of 1473 eligible pts (1384 from EU, 89 from US) 63% diagnosed in 2001-2010. Median age at diagnosis (Dx) was 68.5 ys. Of pts with known M status at Dx, 56 (5.1%) were M1; of 1046 M0 cases, 60% were N0 and 51% had T1 tumors at Dx; 4% of pts had BCS and 18% had SLNB; half received adjuvant RT. (Neo)adjuvant CT was used in 30% of M0 pts, most (44%) anthracycline-only; 77% of M0 pts received adjuvant ET, most tamoxifen (88.4%). Central pathology: 697 cases with central histology & grade (full series ongoing): 87% ductal, 53% grade 2. In 1473 pts, at least 1 biomarker centrally assessed; 92% ER highly+ (Allred 7-8), PR had wider variation (35% highly+); 87% AR highly+; 25% Ki67 high; 5% HER2pos. Using IHC surrogates: 58% Luminal A-like, 35% LuminalB-like/HER2neg, 6% LuminalB-like/HER2pos; 0.1% HER2pos/non-Luminal; 1% TNBC (16% not classified). Outcome: For 1046 M0 pts, median FU was 5.7 yrs (0-19.2); 63% alive at analysis; in 88% cause of death was reported, mainly 33% non-cancer and 28% progression(PD)/toxicity. Significant OS improvement over time is seen. 75% (42/56) M1 pts died, mainly due PD. In M0 pts, median OS (yrs) was significantly correlated with ER+ p=0.001 [Allred 0-2: 3.9 (0.1, 6.0); 3-6: 7.1 (4.7, 11.7); 7-8: 8.8 (8.3, 10.0)] & with PR+ p=0.022 [Allred 0-2: 7.3 (6.1, 10.3), 3-6: 8.0 (7.0, 9.3), 7-8: 9.5 (8.4, 12.8)]; less correlation for AR; no major differences for HER2 or Ki67. Median OS & grade (394 cases; full series ongoing): Grade1: 12.8 yrs (6.1-15.6); Grade2: 7.9 (6.5-10.7); Grade3: 9.3 (4.9-21.1). Median OS for IHC surrogates: 8.7 (7.8-9.7) for Luminal A; 8.3 (6.9-9.4) for Luminal B/HER-2neg; 9.3 years (5.9-21.1) for Luminal B/HER-2+. Similar results were seen for RFS. ER/PR/AR using histoscores will be presented. Conclusions: a) 56% pts had T1 tumors at Dx but only 4% had BCS; b) ER was highly + in &gt;90% but adjuvant ET given in only 77% pts; c) Male BC is usually ER+, PR+ & AR+ and of Luminal A-like subtype (5% HER2pos & 1% TNBC); d) Significant improvement in OS over time; e) ER and PR (Allred) are prognostic (high expression/better prognosis), less for AR, not for Ki67 nor IHC surrogates; f) In-depth characterization of samples is ongoing. Funding: BCRF, EBCC Council, Pink Ribbon NL, BRO. Citation Format: Fatima Cardoso, John Bartlett, Leen Slaets, Carolien van Deurzen, Elise van Leewen-Stok, Peggy Porter, Barbro Linderholm, Ingrid Hedenfalk, Carolien Schroder, John Martens, Jane Bayani, Christi van Asperen, Melissa Murray, Clifford Hudis, Lavinia Middleton, Joanna Vermeij, Stephanie Peeters, Judith Fraser, Monica Nowaczyk, Isabel Rubio, Stefan Aebi, Catherine Kelly, Kathryn Ruddy, Eric Winer, Cecilia Nilsson, Lissandra Dal Lago, Larissa Korde, Kim Benstead, Danielle Van Den Weyngaert, Oliver Bogler, Theodora Goulioti, Nicolas Dif, Carlo Messina, Konstantinos Tryfonidis, Jan Bogaerts, Sharon Giordano. Characterization of male breast cancer: First results of the EORTC10085/TBCRC/BIG/NABCG International Male BC Program [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S6-05.