bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endogenous knock-down of survival genes improves chemotherapeutic response in a T-ALL cell line
Authors: Morrison D. , Moskowitz N. , Bhojwani D. , Lee H. , Patel B. , Horton T. , Raetz E. , Carroll W. 
Published: March 2020

9522 Background: New targets for more effective, less toxic therapeutic approaches to childhood acute lymphoblastic leukemia (ALL) can be developed by discovering pathways unique to the blast. Using microarray technology, we identified potential target genes that are up-regulated at relapse compared to diagnosis (Blood 2006;108:711–7). Two genes, survivin and securin, were selected for analysis because they are involved in cell cycle regulation, apoptosis and cellular transformation. We hypothesized that decreasing endogenous expression of these genes would increase apoptosis and sensitize cells to chemotherapy. Methods: Short hairpin RNA constructs (shRNA) targeting both transcripts and a control shRNA were engineered. LSN2181295 (sodium salt of LY2181308), an antisense molecule targeting survivin developed by Eli Lilly and its mismatch control (LSN2293329) were also tested. The T- ALL cell line Molt4 was transiently transfected with shRNA constructs or antisense oligos. Western blot and qRT-PCR were performed to determine the time course of target knock-down while apoptosis was assessed by annexin-V labeling. Following transfection, cells were also treated with varying doses of etoposide and doxorubicin for 24 hrs prior to FACS analysis. Results: The survivin and securin shRNAs blocked endogenous gene expression by 80–90%, with maximal effect achieved at 48 hrs. Transfection of Molt4 cells with survivin and securin shRNAs induced ∼13% and 35% apoptosis, respectively, as compared to a control shRNA. When used in combination with chemotherapeutic agents, the shRNA constructs potentiated the effect of both doxorubicin and etoposide at low dosages (≤100 nM and ≤0.4 uM respectively, p values <0.01). The antisense survivin drug had a similar effect as the survivin shRNA and also potentiated the effect of vincristine. Conclusion: Targeting levels of survivin and securin in conjunction with standard chemotherapy maximizes leukemia cell kill and effectively lowers the amount of chemotherapy needed to achieve cell death. Such an approach may improve overall survival for patients at relapse and could also lead to the delivery of effective chemotherapy at less toxic doses. No significant financial relationships to disclose.
In vitro evaluation of the PARP inhibitor ABT-888 in combination with temozolomide for the treatment of pediatric leukemia
Authors: Horton T. M. , Zhang L. , Jenkins G. N. , Berg S. L. , Blaney S. M. 
Published: March 2020

9528 Background: The alkylating agent temozolomide exerts its primary cytotoxic activity through the addition to O6 methyl adducts to guanine residues in DNA, and temozolomide resistance results either from increased expression of methyl-guanine DNA methyltransferase (MGMT), which removes O6 adducts, or from mutations in the mismatch repair system (MRS), which lead to microsatellite instability (MSI). Temozolomide also creates N3 and N7 methyl adducts that are efficiently removed by the base excision repair (BER) system. PARP inhibitors block BER and may potentiate the cytotoxic effects of temozolomide. Methods: The cytotoxicity of temozolomide in combination with the PARP inhibitor ABT-888 was evaluated in vitro in leukemia cell lines and primary leukemia cells using the MTT assay. PARP activity was measured using a commercially available PARP assay. Results: ABT-888 effectively enhanced temozolomide cytotoxicity in cell lines with elevated MGMT (Jurkat and HSB2 T-cell ALL cell lines) or MRS deficiencies (Jurkat and Molt-4 T cell ALL). The temozolomide IC50 decreased from 450 μM to 35 μM at an ABT-888 concentration of 5 μM in the Jurkat T-cell ALL cell line and from 340 μM to 7.5 μM in the HSB2 T-cell line. ABT-888 also enhanced temozolomide cytotoxicity in non-T-cell leukemia subtypes, decreasing the IC50 in the JM1 pre-B ALL cell line from 51 μM to 7.7 μM and decreasing the IC50 from 316 μM to 22 μM in tumor cells obtained from a patient with pre-B ALL. PARP activity was also examined. In contrast, the sensitivity of U937 AML cells to temozolomide showed no effect of the addition of a PARP inhibitor. These results are consistent with the findings that these cells have low or undetectable MGMT and no MSI to suggest MRS mutations. Conclusion: These results suggest that ABT-888 may enhance the cytotoxic activity of temozolomide in leukemia patients whose tumors are resistant to temozolomide because of elevated MGMT expression and mismatch repair defects. No significant financial relationships to disclose.
Targeted immunotherapy with gemtuzumab ozogamicin (GO) following reduced intensity allogeneic stem cell transplantation (RI AlloSCT) to reduce minimal residual disease (MRD) in children with acute myeloid leukemia (AML): MRD monitoring by Wilms tumor gene
Authors: Roman E. , Olszewski M. , Kletzel M. , Bhatia M. , Bradley B. , George D. , Garvin J. , Satwani P. , van de Ven C. , Cairo M. S. 
Published: March 2020

9532 Background: RI vs myeloablative (MA) AlloSCT in adults with AML is associated with significantly less transplant related mortality but increased rate of relapse, presumably secondary to MRD (Alyea et al; Blood, 2005). Quantification of the WT1 has been used successfully to detect MRD in children with acute myeloid leukemia (AML) (Kletzel et al; Pediatr Dev Pathol, 2002). GO has induced ORR in >30% of patients with overt relapsed CD33+ AML and may have a better effect in the setting of MRD (Sievers et al; J Clin Oncol, 2001). We have shown that RI AlloSCT followed by 2 doses of GO in average risk AML has resulted in >94% donor chimerism (Roman/Cairo, Clin Can Res, 2005). We explored changes in MRD prior to and after consolidation with 2 doses of GO targeted immunotherapy in children with average risk AML post RI AlloSCT. Methods: 11 pts, 11 years (0.5–21) with CD33+ (8 CR1, 3 CR2) received fludarabine 30 mg/m2x6d and busulfan 3.2–4 mg/kgx2d. Donors: 7 6/6 HLA related peripheral blood stem cells (RPBSC), 1 5/6 RPBSC, 1 6/6 related cord blood (CB) and 2 4/6 unrelated CB. GOx2 was administered =60d post AlloSCTx2 (8wks apart), at 4.5–7.5 mg/m2 (dose escalation). Samples were collected for WT1 analysis prior to and after each dose of GO (n=5). WT1 levels were determined by quantitative RT-PCR and compared with WT1 expression in a K562 leukemia line. Positive MRD was a ratio of K562 WT/patient's WT1>0.5. Results: The MTD for GO post RI AlloSCT has not been reached. 8/11 are NED (3 deaths: 1 relapse, 1 graft failure, 1 cGVHD) Pre GO WT1–0.079±0.07 (n=5), pre GO-dose #2–0.012±0.016 (n=3). One of these patients had detectable MRD (WT1–1.56) prior to the GO-dose #2, no MRD at 1year and is alive and in remission at 2 years post GOx2. The fifth patient entered transplant with +MRD (WT-0.866), relapsed after the first dose of GO and died of relapse prior to receiving the second dose. Conclusions: Targeted therapy with GOx2 may be useful in eradicating MRD in patients post RI AlloSCT. A larger cohort is necessary to assess the impact of GO (at the MTD) on MRD post RI AlloSCT in children with AML. No significant financial relationships to disclose.
Treatment of acute myeloid meukemia with a mrc aml 10 modified regime in Mexican children
Authors: Gallegos Castorena S. , Medina Sanson A. , Zapata Tarres M. , Dorantes Acosta E. , Martinez Avalos A. 
Published: March 2020

9533 Background: The results of treatment in acute myeloid leukemia had been limited. We have obtained event free survival of 17% in patients treated in our Institution from 1990–2003. The availability of stem cell transplantation is limited in our country. The objective of the present study was to assessed the remission rate, event-free and overall survival obtained with and intense chemotherapy regime. Methods: We designed a prospective study using a MRC AML 10 modified protocol from February 2003 to September 2005 for patients diagnosed with de novo AML 0 to 18 years. Patients were classified as high risk if they presented with M4 or M5 morphology, >100,000 WBC/mm3, positive CSF, t(11;23) or > 1 cycle to achieve remission. Induction consisted on two cycles of daunorubicin 50 mg/m2/day 1, 3 and 5; cytarabine 100 mg/m2/dose twice days 1–10 and etoposide 100 mg/m2/day 1–5; in the second cycle cytarabine was scheduled for 8 days. Consolidation consisted on 4 alternating cycles of etoposide 100 mg/m2/day 1–5 and cytarabine 1 gr/m2/dose twice day 1–3 alternating with mitoxantrone 10 mg/m2/day 1–5 and cytarabine 1 gr/m2/dose twice day 1–3. All patients received triple intrathecal chemotherapy every cycle and craniospinal radiation was limited to patients with >100,000 WBC/mm3 o positive CSF at diagnosis. Remission rate, event-free and overall survival were assessed. Kaplan Meier curve for survival was used. Results: We included 37 patients, 21 male and 16 female, mean age was 8.3 years (11 months-16 years), M1, M2 and M4 subtypes were equally frequent with 21.6% each. Mean leukocyte count was 79,000 (2,100- 525,000). CSF was positive in one patient. 56.8% were classified as high risk patients. Remission was achieved in 91.6%, 75% after the first cycle, 13% after the second and 3% needed more than two cycles. An event free survival of 48.6% (50% for low risk and 47% for high risk) and overall survival of 59.4% were achieved. Relapse rate was high with 35% of patients. Conclusions: The evaluated treatment regime improved our results and was well tolerated. No significant financial relationships to disclose.
Late recurrence in survivors of childhood and adolescent cancer: A report from the Childhood Cancer Survivor Study (CCSS)
Authors: Wasilewski-Masker K. , Leisenring W. , Meacham L. R. , Hammond S. , Meadows A. T. , Robison L. L. , Mertens A. C. 
Published: March 2020

9534 Background: An increasing percentage of childhood cancer patients are surviving their disease, but limited research suggests that late recurrences may impact overall survival. The goal of this study is to estimate late recurrence rates for the most common pediatric cancers and to determine additional risk factors for late recurrence. Methods: CCSS is a retrospective cohort study of five-year survivors of childhood cancer diagnosed before 21 years of age, between 1970 and 1986 at one of 26 consortium centers. Late recurrence was defined as first recurrence occurring > five years post-diagnosis. Recurrences were determined by self-report questionnaire or by confirmation through medical record, death certificate or pathologic review. Probability of late recurrence was calculated using cumulative incidence. Adjusted hazard ratios (HR) were obtained using Cox proportional hazards regression. Results: In 12,948 survivors with no recurrence = five years from diagnosis, 670 (5.2%) subjects had a first recurrence > five years after their primary diagnosis. Late recurrences ranged from 5 to 28.9 years from diagnosis (median 7.9 years). Cumulative incidence varied by diagnosis ( table ). In multivariate analysis, significant risk factors for increased late recurrence included a primary diagnosis of Ewing's sarcoma or CNS tumors (HR of 2.3 and 2.7 respectively vs. leukemia survivors), age = 10 years at diagnosis (HR 1.4 vs. age < 10 years), chemotherapy exposure (HR 1.5 vs. none), and radiation exposure (HR 1.4 vs. none) (p < 0.001 for all). At the time of last follow-up, 51.6% of subjects with a late recurrence had died versus 6.4% of those with no history of recurrence. Conclusions: Late recurrences occur in survivors of childhood cancers with a significant risk of mortality. This emphasizes the importance of long-term survivor follow-up into adulthood, particularly for adolescents and patients with Ewing's sarcoma and CNS tumors. [Table: see text] No significant financial relationships to disclose.
The attainment of life goals by adult survivors of childhood cancer
Authors: Crom D. B. , Lensing S. , Rai S. , Snider M. , Hudson M. M. 
Published: March 2020

9536 Background: Adult survivors of childhood cancer are at risk for disease- and therapy-related morbidity, which can adversely affect marriage and employment status, ability to obtain health insurance and access to care. Our aim was to identify factors associated with survivors’ ability to achieve these goals. Methods: We surveyed 1,437 survivors of different types of childhood cancer who were >18 years of age and >10 years from diagnosis. We compared our cohort's data to normative data in the Medical Expenditure Panel Survey and the Current Population Surveys of the U.S. Census Bureau. Survivors were categorized into 3 groups (hematological malignancy, solid tumors, or central nervous system tumors) and whether they had received radiation therapy. Results: The majority of respondents (response rate 65%) were survivors of hematological malignancies (71%), white (91%), and working full-time (62%); (43%) were married. When compared to age- and gender-adjusted national averages, only survivors of hematological malignancy who received radiation therapy were significantly less likely to be married than the general population (44% vs. 52%). Full-time employment among survivors was lower than national norms, except for survivors of hematological malignancy who had not received radiation therapy. The prevalence of having any health insurance, especially public insurance, was higher in all diagnostic groups than in the general population. Difficulty obtaining care was reported by 11% of all survivors; 12% reported not receiving needed health care. Additionally, 26.9% reported having been denied insurance. Current unemployment and lack of insurance were significantly associated with difficulty in obtaining care (p=0.049 and p<0.001, respectively). CNS tumor survivors reported greater difficulty in obtaining needed care (p=0.030). Current employment and solid tumor diagnosis were associated with lower rates of denial of insurance (p=0.018 and p=0.003, respectively). Conclusion: Subgroups of adult childhood cancer survivors are at risk of problems with attaining life goals, including access to care. This has serious implications given the known long-term secondary medical complications in this at- risk population. No significant financial relationships to disclose.
Dominant negative Hes1 blocks osteosarcoma invasion driven by Notch pathway signaling
Authors: Hughes D. P. , Zhang P. , Yang Y. , Lee K. E. , Zweidler-McKay P. A. 
Published: March 2020

9549 Background: Osteosarcoma (OS) is the most common bone cancer, with a peak incidence in mid-adolescence. OS outcome is poor for metastatic or recurrent disease (<30% and 10–20% survival respectively at 5 years). We investigated mechanisms regulating invasion and metastasis to identify new therapeutic targets for OS. One potential target is γ-secretase, required for activating Notch, Her-4 and β-catenin pathways. We have shown previously that Notch pathways genes are expressed in OS cells, and recently identified an association between Notch-mediated Hes1 expression and OS invasiveness. Here we sought to determine if OS invasiveness could be eliminated by direct blockade of Hes1 function. Methods: OS cell lines OS 187, COL, Saos-2 and Saos2-LM7 (a metastatic subline of Saos-2) were used for all studies. Functional analyses included proliferation, anchorage-independent growth, cell-cycle/apoptosis and matrigel invasion. Notch pathway signaling was genetically manipulated by transduction with constitutively active Notch 1 (ICN1), a dominant negative inhibitor of Notch signaling (dnMAM), normal Hes1, and dominant negative Hes1 (dnHes1). The efficacy of dnHes1 in blocking Hes1 was confirmed in Shep neuroblastoma cells by demonstrating upregulation of Hash1, a gene suppressed by Hes1. Comparisons were made to cells transduced with empty vector (negative control) and cells treated with γ-secretase inhibitor (positive control). Results: Notch pathway manipulation did not affect proliferation, cell cycle or in vitro tumorigenesis. Retroviral transduction with ICN1 or Hes1 increased invasion in all cell lines, and dnMAM reduced invasiveness in OS 187, Saos-2 and LM7, similar to γ-secretase inhibition. Hes1 expression in COL was constitutively active, did not suppress with dnMAM, but invasiveness was proportional to the Hes1 expression. dnHes1 suppressed invasiveness of all lines, indicating the importance of Hes1 expression in regulating invasion, an essential feature of metastasis in OS. Conclusions: Hes1 expression may be useful as a marker of increased metastatic risk. Therapies blocking Hes1 expression, including γ-secretase inhibitors, may have therapeutic potential for OS. Further preclinical and clinical trials are warranted. No significant financial relationships to disclose.
Phase I study of erlotinib administered concurrently with and after irradiation (RT) in the treatment of children, adolescents, and young adults with newly diagnosed intracerebral high-grade glioma
Authors: Broniscer A. , Baker S. J. , Merchant T. E. , Laningham F. H. , Kocak M. , Krasin M. J. , Kun L. E. , Gajjar A. , Stewart C. F. 
Published: March 2020

9553 Background: High-grade gliomas are uncommon neoplasms in childhood that portend a poor prognosis. Because of the promising activity of erlotinib in adults with high-grade glioma, we conducted this Phase I study to determine the maximum tolerated dose and dose limiting toxicity (DLT) of erlotinib administered concurrently with and after RT. Methods: Patients between 3 and 25 years of age with newly diagnosed high-grade glioma received erlotinib continuously once daily during and after RT for a maximum of 52 weeks. Pharmacokinetic studies of erlotinib and its metabolite OSI-420, and genotyping were performed during course 1 in consenting patients. Use of enzyme-inducing anticonvulsants was an exclusion criterion. Dose escalation followed a typical Phase I design (dosage levels of 70, 90, and 120 mg/m2 per day). The DLT-evaluation period comprised the first 8 weeks of erlotinib. Results: Seventeen patients (median age 10.4 yrs; 10 males) were enrolled. Diagnoses consisted of glioblastoma (n=9), anaplastic astrocytoma (n=4), and other high-grade gliomas (n=4). Two of seven patients experienced reversible grade 3 hypokalemia / hypophosphatemia at the 70 mg/m2 level. Once electrolyte abnormalities were excluded as DLT, only one of seven patients at the 120 mg/m2 level has experienced grade 3 diarrhea so far. Pharmacokinetic studies were obtained in 14/17 patients. At the 70 mg/m2 dosage level, the median (range) erlotinib and OSI-420 Cmax and Tmax were 1,405 ng/ml (937–2,180) and 4.1 hr (2.2–8.2) and 158.5 ng/ml (45–203) and 4.1 hr (2.2–7.9), respectively. Three patients have received erlotinib for more than 1 year with disease stabilization. Six patients have already experienced disease progression. Conclusions: Erlotinib administered concurrently with RT on this schedule has been well tolerated. Preliminary pharmacokinetic results are comparable to those observed in adults. Rather than continue to escalate erlotinib dosages, we plan to complete this study and open a phase II study of erlotinib and RT for this same patient population. No significant financial relationships to disclose.
Operating characteristics of two independent sample design in phase I trials in pediatric oncology
Authors: Raphael M. , Le Deley M. , Vassal G. , Paoletti X. 
Published: March 2020

9555 Background: The European Medicine Agency (EMEA) stated that the degree of pre-treatments can modify the patient's tolerance to new treatments in pediatrics oncology, and then suggested that exploration of this potential difference should be considered. It is current practice to split a phase I trial in two groups to identify the Maximum Tolerated Dose (MTD) in each group. Yet how relevant such approach is, has not been investigated. In particular, role of baseline characteristics has not been explored. Methods: We reanalyze a large phase I trial of CPT11 in which 80 children had been included (32 heavily pre-treated pts and 48 less heavily pre-treated) to determine if baseline characteristics were associated with the heaviness of pre-treatment and could predict serious adverse events. To investigate robustness of conclusions in the context of small sample sizes, we performed an extended simulation study. We explored dose recommendations in scenarios with group difference, as measured by Odds Ratio (OR), ranging from 1 (absence of difference) to 8 (large difference) and sample size increasing from 2 * 20 to 2*40. Results: We did not find any relation between the degree and pre- treatment and neither the risk of DLT nor the baseline characteristics in this pediatric trial. However robustness appeared to be critical with high risk of misidentification of MTD in each of the two groups, whatever the prognostic value. With a group difference corresponding to OR=8 and balanced sample sizes (2*20 pts), the same MTD was identified in 10% of the simulations. Even with larger sample sizes (2*40pts), this figure reached 24% for OR=3. There is also a very high risk of identifying two different MTD although the risk is similar in the two groups (52% for 40 × 2 patients). Conclusions: Two independent sample designs in pediatric phase I trials should be avoided or reserved to limited situations when there is a strong rationale possibly based on adult data. No significant financial relationships to disclose.
Prognostic significance of circulating tumor cells in bone marrow or peripheral blood detected by qualitative and quantitative PCR in pediatric NPM-ALK positive anaplastic large cell lymphoma
Authors: Woessmann W. , Damm-Welk C. , Busch K. , Burkhardt B. , Viehmann S. , Oschlies I. , Klapper W. , Zimmermann M. , Harbott J. , Reiter A. 
Published: March 2020

9559 Background: Clinical and histopathological characteristics have limited prognostic value for children with anaplastic large cell lymphoma (ALCL). We evaluated the presence, extent and prognostic impact of circulating tumor cells in bone marrow (BM) and peripheral blood (PB) of children and adolescents with NPM-ALK positive ALCL by real-time quantitative PCR for NPM-ALK. Methods: Qualitative and TaqMan-based quantitative PCR assays targeting NPM-ALK were developed with a sensitivity to detect 1 NPM-ALK positive cell among 105 cells. Numbers of NPM-ALK transcripts were normalized to 104 copies ABL (NCN). BM was analyzed from 80 and PB from 52 German patients registered into the subsequent protocols NHL-BFM95 and ALCL99. Results: BM was positive for NPM-ALK in 47.5% of patients, and positivity was significantly correlated with clinical stage, mediastinal or visceral involvement, microscopic BM involvement, and histological subtype, but not with skin or CNS involvement. Qualitative and quantitative PCR results in BM and PB strongly correlated. BM PCR was associated with the cumulative incidence of relapses (CI-R): CI-R was 50±10% for 38 PCR-positive and 15±7% for 42 PCR-negative patients (p10 NCN NPM-ALK in BM had a CI-R of 71±14% compared to a CI-R of 18±6% for 59 patients with =10 NCN (p10 NCN NPM-ALK in BM, clinical risk factors (skin, mediastinal or visceral involvement) and atypical histological subtype, only >10 NCN NPM-ALK remained a significant poor prognostic factor with a risk ratio of 4.74 (1.57–14.3; p<0.006). Conclusions: The detection of NPM-ALK positive cells by PCR in BM is associated with advanced stage disease, visceral involvement and atypical histology. Quantitative PCR in BM or PB allows identification of 20% of patients experiencing 60% of all relapses with an event-free survival of 20%. No significant financial relationships to disclose.