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1.
Biomed Pharmacother ; 150: 112993, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35462337

ABSTRACT

Osteosarcoma is the most prevalent malignant bone tumor and occurs most commonly in the adolescent and young adult population. Despite the recent advances in surgeries and chemotherapy, the overall survival in patients with resectable metastases is around 20%. This challenge in osteosarcoma is often attributed to the drastic differences in the tumorigenic profiles and mutations among patients. With diverse mutations and multiple oncogenes, it is necessary to identify the therapies that can attack various mutations and simultaneously have minor side-effects. In this paper, we constructed the osteosarcoma pathway from literature and modeled it using ordinary differential equations. We then simulated this network for every possible gene mutation and their combinations and ranked different drug combinations based on their efficacy to drive a mutated osteosarcoma network towards cell death. Our theoretical results predict that drug combinations with Cryptotanshinone (C19H20O3), a traditional Chinese herb derivative, have the best overall performance. Specifically, Cryptotanshinone in combination with Temsirolimus inhibit the JAK/STAT, MAPK/ERK, and PI3K/Akt/mTOR pathways and induce cell death in tumor cells. We corroborated our theoretical predictions using wet-lab experiments on SaOS2, 143B, G292, and HU03N1 human osteosarcoma cell lines, thereby demonstrating the potency of Cryptotanshinone in fighting osteosarcoma.


Subject(s)
Bone Neoplasms , Osteosarcoma , Adolescent , Apoptosis , Bone Neoplasms/pathology , Cell Line , Cell Line, Tumor , Cell Proliferation , Humans , Osteosarcoma/pathology , Phenanthrenes , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Young Adult
2.
IEEE/ACM Trans Comput Biol Bioinform ; 19(3): 1683-1693, 2022.
Article in English | MEDLINE | ID: mdl-33180729

ABSTRACT

Osteosarcoma (OS) is the most common primary malignant bone tumor of both children and pet canines. Its characteristic genomic instability and complexity coupled with the dearth of knowledge about its etiology has made improvement in the current treatment difficult. We use the existing literature about the biological pathways active in OS and combine it with the current research involving natural compounds to identify new targets and design more effective drug therapies. The key components of these pathways are modeled as a Boolean network with multiple inputs and multiple outputs. The combinatorial circuit is employed to theoretically predict the efficacies of various drugs in combination with Cryptotanshinone. We show that the action of the herbal drug, Cryptotanshinone on OS cell lines induces apoptosis by increasing sensitivity to TNF-related apoptosis-inducing ligand (TRAIL) through its multi-pronged action on STAT3, DRP1 and DR5. The Boolean framework is used to detect additional drug intervention points in the pathway that could amplify the action of Cryptotanshinone.


Subject(s)
Bone Neoplasms , Osteosarcoma , Animals , Apoptosis , Bone Neoplasms/drug therapy , Bone Neoplasms/metabolism , Bone Neoplasms/pathology , Cell Line, Tumor , Computer Simulation , Dogs , Osteosarcoma/drug therapy , Osteosarcoma/metabolism , Osteosarcoma/pathology , Phenanthrenes
3.
PLoS One ; 16(2): e0247190, 2021.
Article in English | MEDLINE | ID: mdl-33596259

ABSTRACT

Colorectal cancer (CRC) is one of the most prevalent types of cancer in the world and ranks second in cancer deaths in the US. Despite the recent improvements in screening and treatment, the number of deaths associated with CRC is still very significant. The complexities involved in CRC therapy stem from multiple oncogenic mutations and crosstalk between abnormal pathways. This calls for using advanced molecular genetics to understand the underlying pathway interactions responsible for this cancer. In this paper, we construct the CRC pathway from the literature and using an existing public dataset on healthy vs tumor colon cells, we identify the genes and pathways that are mutated and are possibly responsible for the disease progression. We then introduce drugs in the CRC pathway, and using a boolean modeling technique, we deduce the drug combinations that produce maximum cell death. Our theoretical simulations demonstrate the effectiveness of Cryptotanshinone, a traditional Chinese herb derivative, achieved by targeting critical oncogenic mutations and enhancing cell death. Finally, we validate our theoretical results using wet lab experiments on HT29 and HCT116 human colorectal carcinoma cell lines.


Subject(s)
Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Phenanthrenes/therapeutic use , Cell Death/drug effects , Cell Death/genetics , Cell Proliferation/drug effects , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic , HCT116 Cells , HT29 Cells , Humans , Mutation/genetics , Signal Transduction/drug effects , Signal Transduction/genetics
4.
PLoS One ; 16(2): e0236074, 2021.
Article in English | MEDLINE | ID: mdl-33544704

ABSTRACT

BACKGROUND: Several studies have highlighted both the extreme anticancer effects of Cryptotanshinone (CT), a Stat3 crippling component from Salvia miltiorrhiza, as well as other STAT3 inhibitors to fight cancer. METHODS: Data presented in this experiment incorporates 2 years of in vitro studies applying a comprehensive live-cell drug-screening analysis of human and canine cancer cells exposed to CT at 20 µM concentration, as well as to other drug combinations. As previously observed in other studies, dogs are natural cancer models, given to their similarity in cancer genetics, epidemiology and disease progression compared to humans. RESULTS: Results obtained from several types of human and canine cancer cells exposed to CT and varied drug combinations, verified CT efficacy at combating cancer by achieving an extremely high percentage of apoptosis within 24 hours of drug exposure. CONCLUSIONS: CT anticancer efficacy in various human and canine cancer cell lines denotes its ability to interact across different biological processes and cancer regulatory cell networks, driving inhibition of cancer cell survival.


Subject(s)
Neoplasms/drug therapy , Phenanthrenes/metabolism , Phenanthrenes/pharmacology , Animals , Apoptosis/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Dogs , Early Detection of Cancer/methods , Humans , Neoplasms/metabolism , STAT3 Transcription Factor/antagonists & inhibitors , Salvia miltiorrhiza/metabolism , Signal Transduction/drug effects
5.
Radiat Res ; 196(5): 478-490, 2020 11 01.
Article in English | MEDLINE | ID: mdl-32931585

ABSTRACT

Internal contamination by radionuclides may constitute a major source of exposure and biological damage after radiation accidents and potentially in a dirty bomb or improvised nuclear device scenario. We injected male C57BL/6 mice with radiolabeled cesium chloride solution (137CsCl) to evaluate the biological effects of varying cumulative doses and dose rates in a two-week study. Injection activities of 137CsCl were 5.71, 6.78, 7.67 and 9.29 MBq, calculated to achieve a target dose of 4 Gy at days 14, 7, 5 and 3, respectively. We collected whole blood samples at days 2, 3, 5, 7 and 14 so that we can publish the issue in Decemberfrom all injection groups and measured gene expression using Agilent Mouse Whole Genome microarrays. We identified both dose-rate-independent and dose-rate-dependent gene expression responses in the time series. Gene Ontology analysis indicated a rapid and persistent immune response to the chronic low-dose-rate irradiation, consistent with depletion of radiosensitive B cells. Pathways impacting platelet aggregation and TP53 signaling appeared activated, but not consistently at all times in the study. Clustering of genes by pattern and identification of dose-rate-independent and -dependent genes provided insight into possible drivers of the dynamic transcriptome response in vivo, and also indicated that TP53 signaling may be upstream of very different transcript response patterns. This characterization of the biological response of blood cells to internal radiation at varying doses and dose rates is an important step in understanding the effects of internal contamination after a nuclear event.


Subject(s)
Cesium Radioisotopes , Radiation Dosage , Animals , DNA Repair , Gene Ontology , Male , Mice
6.
Article in English | MEDLINE | ID: mdl-30222582

ABSTRACT

In this work, we develop a systematic approach for applying pathway knowledge to a multivariate Gaussian mixture model for dissecting a heterogeneous cancer tissue. The downstream transcription factors are selected as observables from available partial pathway knowledge in such a way that the subpopulations produce some differential behavior in response to the drugs selected in the upstream. For each subpopulation, each unique (drug, observable) pair is considered as a unique dimension of a multivariate Gaussian distribution. Expectation-maximization (EM) algorithm with hill-climbing is then used to rank the most probable estimates of the mixture composition based on the log-likelihood value. A major contribution of this work is to examine the efficacy of the EM based approach in estimating the composition of experimental mixture sets from cell-by-cell measurements collected on a dynamic cell imaging platform. Towards this end, we apply the algorithm on hourly data collected for two different mixture compositions of A2058, HCT116, and SW480 cell lines for three scenarios: untreated, Lapatinib-treated, and Temsirolimus-treated. Additionally, we show how this methodology can provide a basis for comparing the killing rate of different drugs for a heterogeneous cancer tissue. This obviously has important implications for designing efficient drugs for treating heterogeneous malignant tumors.


Subject(s)
Algorithms , Antineoplastic Agents/pharmacology , Computational Biology/methods , Neoplasms , Cell Line, Tumor , Cell Proliferation/drug effects , Humans , MAP Kinase Signaling System , Neoplasms/classification , Neoplasms/metabolism , Normal Distribution
7.
IEEE/ACM Trans Comput Biol Bioinform ; 17(3): 1010-1018, 2020.
Article in English | MEDLINE | ID: mdl-30281473

ABSTRACT

The number of deaths associated with Pancreatic Cancer has been on the rise in the United States making it an especially dreaded disease. The overall prognosis for pancreatic cancer patients continues to be grim because of the complexity of the disease at the molecular level involving the potential activation/inactivation of several diverse signaling pathways. In this paper, we first model the aberrant signaling in pancreatic cancer using a multi-fault Boolean Network. Thereafter, we theoretically evaluate the efficacy of different drug combinations by simulating this boolean network with drugs at the relevant intervention points and arrive at the most effective drug(s) to achieve cell death. The simulation results indicate that drug combinations containing Cryptotanshinone, a traditional Chinese herb derivative, result in considerably enhanced cell death. These in silico results are validated using wet lab experiments we carried out on Human Pancreatic Cancer (HPAC) cell lines.


Subject(s)
Computational Biology/methods , Computer Simulation , Pancreatic Neoplasms , Phenanthrenes/pharmacology , Signal Transduction , Algorithms , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Drug Therapy, Combination , Humans , Signal Transduction/drug effects , Signal Transduction/genetics
8.
IEEE J Biomed Health Inform ; 24(8): 2430-2438, 2020 08.
Article in English | MEDLINE | ID: mdl-31825884

ABSTRACT

Signaling pathways oversee highly efficient cellular mechanisms such as growth, division, and death. These processes are controlled by robust negative feedback loops that inhibit receptor-mediated growth factor pathways. Specifically, the ERK, the AKT, and the S6K feedback loops attenuate signaling via growth factor receptors and other kinase receptors to regulate cell growth. Irregularity in any of these supervised processes can lead to uncontrolled cell proliferation and possibly Cancer. These irregularities primarily occur as mutated genes, and an exhaustive search of the perfect drug combination by performing experiments can be both costly and complex. Hence, in this paper, we model the Lung Cancer pathway as a Modified Boolean Network that incorporates feedback. By simulating this network, we theoretically predict the drug combinations that achieve the desired goal for the majority of mutations. Our theoretical analysis identifies Cryptotanshinone, a traditional Chinese herb derivative, as a potent drug component in the fight against cancer. We validated these theoretical results using multiple wet lab experiments carried out on H2073 and SW900 lung cancer cell lines.


Subject(s)
Cell Death/drug effects , Feedback, Physiological/drug effects , Gene Regulatory Networks/drug effects , Lung Neoplasms , Phenanthrenes/pharmacology , Cell Line, Tumor , Humans , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Signal Transduction/drug effects
9.
IEEE Trans Biomed Eng ; 66(9): 2684-2692, 2019 09.
Article in English | MEDLINE | ID: mdl-30676941

ABSTRACT

OBJECTIVE: Breast cancer is the second leading cause of cancer death among US women; hence, identifying potential drug targets is an ever increasing need. In this paper, we integrate existing biological information with graphical models to deduce the significant nodes in the breast cancer signaling pathway. METHODS: We make use of biological information from the literature to develop a Bayesian network. Using the relevant gene expression data we estimate the parameters of this network. Then, using a message passing algorithm, we infer the network. The inferred network is used to quantitatively rank different interventions for achieving a desired phenotypic outcome. The particular phenotype considered here is the induction of apoptosis. RESULTS: Theoretical analysis pinpoints to the role of Cryptotanshinone, a compound found in traditional Chinese herbs, as a potent modulator for bringing about cell death in the treatment of cancer. CONCLUSION: Using a mathematical framework, we showed that the combination therapy of mTOR and STAT3 genes yields the best apoptosis in breast cancer. SIGNIFICANCE: The computational results we arrived at are consistent with the experimental results that we obtained using Cryptotanshinone on MCF-7 breast cancer cell lines and also by the past results of others from the literature, thereby demonstrating the effectiveness of our model.


Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms , Computational Biology/methods , Drug Discovery/methods , Apoptosis/drug effects , Bayes Theorem , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Female , Gene Regulatory Networks/drug effects , Humans , MCF-7 Cells , Phenanthrenes/pharmacology
10.
BMC Cancer ; 18(1): 855, 2018 Aug 29.
Article in English | MEDLINE | ID: mdl-30157799

ABSTRACT

BACKGROUND: Metastatic melanoma is an aggressive form of skin cancer that evades various anti-cancer treatments including surgery, radio-,immuno- and chemo-therapy. TRAIL-induced apoptosis is a desirable method to treat melanoma since, unlike other treatments, it does not harm non-cancerous cells. The pro-inflammatory response to melanoma by nF κB and STAT3 pathways makes the cancer cells resist TRAIL-induced apoptosis. We show that due to to its dual action on DR5, a death receptor for TRAIL and on STAT3, Cryptotanshinone can be used to increase sensitivity to TRAIL. METHODS: The development of chemoresistance and invasive properties in melanoma cells involves several biological pathways. The key components of these pathways are represented as a Boolean network with multiple inputs and multiple outputs. RESULTS: The possible mutations in genes that can lead to cancer are captured by faults in the combinatorial circuit and the model is used to theoretically predict the effectiveness of Cryptotanshinone for inducing apoptosis in melanoma cell lines. This prediction is experimentally validated by showing that Cryptotanshinone can cause enhanced cell death in A375 melanoma cells. CONCLUSION: The results presented in this paper facilitate a better understanding of melanoma drug resistance. Furthermore, this framework can be used to detect additional drug intervention points in the pathway that could amplify the action of Cryptotanshinone.


Subject(s)
Apoptosis/drug effects , Apoptosis/genetics , Models, Biological , Phenanthrenes/pharmacology , Algorithms , Biomarkers , Cell Line, Tumor , Computational Biology/methods , Computer Simulation , Drugs, Chinese Herbal/pharmacology , Gene Expression Profiling , Humans , Melanoma/genetics , Melanoma/metabolism , Mitochondria/drug effects , Mitochondria/metabolism , NF-kappa B/metabolism , Reproducibility of Results , Signal Transduction , Transcriptome
11.
Cancer Inform ; 17: 1176935118771701, 2018.
Article in English | MEDLINE | ID: mdl-29881253

ABSTRACT

Features for standard expression microarray and RNA-Seq classification are expression averages over collections of cells. Single cell provides expression measurements for individual cells in a collection of cells from a particular tissue sample. Hence, it can yield feature vectors consisting of higher order and mixed moments. This article demonstrates the advantage of using these expression moments in cancer-related classification. We use synthetic data generated from 2 real networks, the mammalian cell cycle network and a melanoma-related pathway network, and real single-cell data generated via fluorescent protein reporters from 2 cell lines, HT-29 and HCT-116. The networks consist of hidden binary regulatory networks with Gaussian observations. The steady-state distributions of both the original and mutated networks are found, and data are drawn from these for moment-based classification using the mean, variance, skewness, and mixed moments. For the real data, we only observe 1 gene at a time, so that only the mean, variance, and skewness are considered, the analysis being done for 2 genes, EGFR and ERRB2. For the synthetic data, classification improves as we move from just the mean to mean, variance, and skewness and then to these plus the mixed moments. Comparisons are done with 3, 4, or 5 features, using feature selection. Sample size effects are considered. For the real data, we only consider mean, variance, and skewness, with results improving when the higher order moments are used as features.

12.
PLoS One ; 13(6): e0198851, 2018.
Article in English | MEDLINE | ID: mdl-29879226

ABSTRACT

PURPOSE: To compile a list of genes that have been reported to be affected by external ionizing radiation (IR) and to assess their performance as candidate biomarkers for individual human radiation dosimetry. METHODS: Eligible studies were identified through extensive searches of the online databases from 1978 to 2017. Original English-language publications of microarray studies assessing radiation-induced changes in gene expression levels in human blood after external IR were included. Genes identified in at least half of the selected studies were retained for bio-statistical analysis in order to evaluate their diagnostic ability. RESULTS: 24 studies met the criteria and were included in this study. Radiation-induced expression of 10,170 unique genes was identified and the 31 genes that have been identified in at least 50% of studies (12/24 studies) were selected for diagnostic power analysis. Twenty-seven genes showed a significant Spearman's correlation with radiation dose. Individually, TNFSF4, FDXR, MYC, ZMAT3 and GADD45A provided the best discrimination of radiation dose < 2 Gy and dose ≥ 2 Gy according to according to their maximized Youden's index (0.67, 0.55, 0.55, 0.55 and 0.53 respectively). Moreover, 12 combinations of three genes display an area under the Receiver Operating Curve (ROC) curve (AUC) = 1 reinforcing the concept of biomarker combinations instead of looking for an ideal and unique biomarker. CONCLUSION: Gene expression is a promising approach for radiation dosimetry assessment. A list of robust candidate biomarkers has been identified from analysis of the studies published to date, confirming for example the potential of well-known genes such as FDXR and TNFSF4 or highlighting other promising gene such as ZMAT3. However, heterogeneity in protocols and analysis methods will require additional studies to confirm these results.


Subject(s)
Carrier Proteins/blood , Gene Expression Regulation/radiation effects , Nuclear Proteins/blood , OX40 Ligand/blood , Radiation Injuries/blood , Radiation, Ionizing , Biomarkers/blood , Humans , RNA-Binding Proteins , Radiometry
13.
Clin Cancer Res ; 21(15): 3561-8, 2015 Aug 01.
Article in English | MEDLINE | ID: mdl-25695692

ABSTRACT

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is characterized by high levels of fibrosis, termed desmoplasia, which is thought to hamper the efficacy of therapeutics treating PDAC. Our primary focus was to evaluate differences in the extent of desmoplasia in primary tumors and metastatic lesions. As metastatic burden is a primary cause for mortality in PDAC, the extent of desmoplasia in metastases may help to determine whether desmoplasia targeting therapeutics will benefit patients with late-stage, metastatic disease. EXPERIMENTAL DESIGN: We sought to assess desmoplasia in metastatic lesions of PDAC and compare it with that of primary tumors. Fifty-three patients' primaries and 57 patients' metastases were stained using IHC staining techniques. RESULTS: We observed a significant negative correlation between patient survival and extracellular matrix deposition in primary tumors. Kaplan-Meier curves for collagen I showed median survival of 14.6 months in low collagen patients, and 6.4 months in high-level patients (log rank, P < 0.05). Low-level hyaluronan patients displayed median survival times of 24.3 months as compared with 9.3 months in high-level patients (log rank, P < 0.05). Our analysis also indicated that extracellular matrix components, such as collagen and hyaluronan, are found in high levels in both primary tumors and metastatic lesions. The difference in the level of desmoplasia between primary tumors and metastatic lesions was not statistically significant. CONCLUSIONS: Our results suggest that both primary tumors and metastases of PDAC have highly fibrotic stroma. Thus, stromal targeting agents have the potential to benefit PDAC patients, even those with metastatic disease.


Subject(s)
Adenocarcinoma/metabolism , Biomarkers, Tumor/metabolism , Carcinoma, Pancreatic Ductal/metabolism , Extracellular Matrix/metabolism , Adenocarcinoma/pathology , Adult , Aged , Aged, 80 and over , Carcinoma, Pancreatic Ductal/pathology , Collagen Type I/metabolism , Collagen Type IV/metabolism , Disease-Free Survival , Extracellular Matrix/pathology , Female , Humans , Hyaluronic Acid/metabolism , Kaplan-Meier Estimate , Male , Middle Aged , Neoplasm Metastasis , Prognosis , Tissue Array Analysis
14.
Cancer Inform ; 14(Suppl 5): 33-43, 2015.
Article in English | MEDLINE | ID: mdl-26997864

ABSTRACT

The landscape of translational research has been shifting toward drug combination therapies. Pairing of drugs allows for more types of drug interaction with cells. In order to accurately and comprehensively assess combinational drug efficacy, analytical methods capable of recognizing these alternative reactions will be required to prioritize those drug candidates having better chances of delivering appreciable therapeutic benefits. Traditional efficacy measures are primarily based on the "extent" of drug inhibition, which is the percentage of cells being killed after drug exposure. Here, we introduce a second dimension of evaluation criterion, speed of killing, based on a live cell imaging assay. This dynamic response trajectory approach takes advantage of both "extent" and "speed" information and uncovers synergisms that would otherwise be missed, while also generating hypotheses regarding important mechanistic modes of drug action.

15.
Mol Cancer Res ; 12(4): 550-9, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24469836

ABSTRACT

UNLABELLED: Insensitivity to standard clinical interventions, including chemotherapy, radiotherapy, and tyrosine kinase inhibitor (TKI) treatment, remains a substantial hindrance towards improving the prognosis of patients with non-small cell lung cancer (NSCLC). The molecular mechanism of therapeutic resistance remains poorly understood. The TNF-like weak inducer of apoptosis (TWEAK)-FGF-inducible 14 (TNFRSF12A/Fn14) signaling axis is known to promote cancer cell survival via NF-κB activation and the upregulation of prosurvival Bcl-2 family members. Here, a role was determined for TWEAK-Fn14 prosurvival signaling in NSCLC through the upregulation of myeloid cell leukemia sequence 1 (MCL1/Mcl-1). Mcl-1 expression significantly correlated with Fn14 expression, advanced NSCLC tumor stage, and poor patient prognosis in human primary NSCLC tumors. TWEAK stimulation of NSCLC cells induced NF-κB-dependent Mcl-1 protein expression and conferred Mcl-1-dependent chemo- and radioresistance. Depletion of Mcl-1 via siRNA or pharmacologic inhibition of Mcl-1, using EU-5148, sensitized TWEAK-treated NSCLC cells to cisplatin- or radiation-mediated inhibition of cell survival. Moreover, EU-5148 inhibited cell survival across a panel of NSCLC cell lines. In contrast, inhibition of Bcl-2/Bcl-xL function had minimal effect on suppressing TWEAK-induced cell survival. Collectively, these results position TWEAK-Fn14 signaling through Mcl-1 as a significant mechanism for NSCLC tumor cell survival and open new therapeutic avenues to abrogate the high mortality rate seen in NSCLC. IMPLICATIONS: The TWEAK-Fn14 signaling axis enhances lung cancer cell survival and therapeutic resistance through Mcl-1, positioning both TWEAK-Fn14 and Mcl-1 as therapeutic opportunities in lung cancer.


Subject(s)
Adenocarcinoma/metabolism , Adenocarcinoma/therapy , Lung Neoplasms/metabolism , Lung Neoplasms/therapy , Myeloid Cell Leukemia Sequence 1 Protein/metabolism , Receptors, Tumor Necrosis Factor/metabolism , Adenocarcinoma/pathology , Adenocarcinoma of Lung , Cell Line, Tumor , Cell Survival/physiology , Humans , Lung Neoplasms/pathology , Myeloid Cell Leukemia Sequence 1 Protein/biosynthesis , Myeloid Cell Leukemia Sequence 1 Protein/genetics , NF-kappa B/metabolism , Proto-Oncogene Proteins c-bcl-2/biosynthesis , RNA, Small Interfering/administration & dosage , RNA, Small Interfering/genetics , Receptors, Tumor Necrosis Factor/administration & dosage , Signal Transduction , TWEAK Receptor , Transfection
16.
EURASIP J Bioinform Syst Biol ; 2014: 15, 2014 Dec.
Article in English | MEDLINE | ID: mdl-28194165

ABSTRACT

Convex bootstrap error estimation is a popular tool for classifier error estimation in gene expression studies. A basic question is how to determine the weight for the convex combination between the basic bootstrap estimator and the resubstitution estimator such that the resulting estimator is unbiased at finite sample sizes. The well-known 0.632 bootstrap error estimator uses asymptotic arguments to propose a fixed 0.632 weight, whereas the more recent 0.632+ bootstrap error estimator attempts to set the weight adaptively. In this paper, we study the finite sample problem in the case of linear discriminant analysis under Gaussian populations. We derive exact expressions for the weight that guarantee unbiasedness of the convex bootstrap error estimator in the univariate and multivariate cases, without making asymptotic simplifications. Using exact computation in the univariate case and an accurate approximation in the multivariate case, we obtain the required weight and show that it can deviate significantly from the constant 0.632 weight, depending on the sample size and Bayes error for the problem. The methodology is illustrated by application on data from a well-known cancer classification study.

17.
J Cancer ; 4(6): 464-7, 2013.
Article in English | MEDLINE | ID: mdl-23901345

ABSTRACT

OBJECTIVE: Phase 1 clinical trials are the first stage of clinical development of an investigational agent. Because the trials often take place at several geographically dispersed sites, safety teleconferences are held to update investigators and the drug sponsor on safety information and other pertinent business related to the trial conduct. Here we examine associations between the frequency of teleconferences and other clinical trial factors on trial conduct efficiency. METHODS: We examined Phase 1 clinical trials for patients with solid tumors opened for enrollment at a single, non-profit cancer center in Arizona (Center) that had completed at least three dose levels. The following information was included: safety teleconference frequency, whether or not the sponsor or contract research organization sent follow-up requests for updates on patient accrual, and safety outside of scheduled safety teleconferences. The dose escalation scheme, route of study drug administration and formulation type (e.g. oral targeted therapy or monoclonal antibody) was also included. RESULTS: Forty-nine Phase 1 studies were examined for inclusion. The majority of safety teleconferences were regularly scheduled (81.6%) with most taking place bi-weekly (46.9%). Additional solicitation for updates outside of scheduled safety teleconferences were requested during the conduct of 31 (63.3%) studies. None of the factors analyzed were significantly associated with accrual, subject dosing, and dose escalation. CONCLUSION: We found that the frequency of teleconferences does not appear to expedite phase 1 study accrual, subject dosing, or dose escalation in the first 3 cohorts of a phase 1 clinical trial.

18.
Am J Clin Oncol ; 36(2): 146-50, 2013 Apr.
Article in English | MEDLINE | ID: mdl-22314002

ABSTRACT

OBJECTIVE: Cancer clinical trials are the means to develop safe and effective novel treatment options for patients. The longer it takes for these trials to reach the recommended phase 2 dose (RP2D), the fewer therapy options are available to patients and physicians. The purpose of this study is to examine the factors that delay RP2D determination in phase 1 clinical trials. METHODS: Thirty-five consecutive phase 1 clinical trials for advanced solid tumors that started between February 2006 and March 2009 in a single institution were examined for inclusion. Factors potentially contributing to trial delays were analyzed against time to determination of an RP2D (TDR). RESULTS: Thirty-one phase 1 clinical trials met the inclusion criteria and were included in the statistical analysis. Investigational agents under evaluation included single agent cytotoxic (N=4), monoclonal antibody (N=3), single agent cytostatic/targeted (N=16), or combination of an investigational agent and commercially available systemic chemotherapy (N=8). A protocol defined phase 2 dose decreased the TDR (P<0.001). Other factors that significantly increased TDR included a larger minimum estimated patient sample size (P=0.022), a greater number of predefined dose levels (P<0.001), and a higher number of expansion cohorts (P=0.038). CONCLUSIONS: Including a predefined phase 2 dose and reducing the number of dose levels and expansion cohorts may shorten phase 1 trial TDR.


Subject(s)
Antineoplastic Agents/administration & dosage , Neoplasms/drug therapy , Adult , Clinical Trials, Phase I as Topic , Clinical Trials, Phase II as Topic , Dose-Response Relationship, Drug , Drug Administration Schedule , Humans , Time Factors
19.
Invest New Drugs ; 31(3): 774-9, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23135779

ABSTRACT

OBJECTIVE: Certain eligibility criteria for Phase 1 cancer clinical trials may impede successful patient enrollment onto a study. We evaluated patient-specific or study-specific reasons for screen failures on Phase 1 oncology clinical trials and discuss factors which may inhibit subject enrollment. METHODS: Thirty-eight Phase 1 clinical trials for solid tumors meeting eligibility criteria and opened for enrollment between February 2006 and February 2011 at one oncology Phase 1 program were examined. Categorical reasons for screen failures and patients' demographics were examined and compared to characteristics of patients that successfully enrolled on a Phase 1 trial. RESULTS: There were a total of 583 successful Phase 1 enrollment and dose administration events out of 773 Phase 1 consent events (75.4 % dose success rate). The three most common reasons for screen failure were: out of protocol-specified range for chemistry, development of an interval medical issue that precluded proceeding with study participation, and subject declining participation after signing consent. Living further away from the Phase 1 program and receipt of fewer prior lines of systemic chemotherapy were significantly associated with increased screen failures. CONCLUSION: Screen failures for Phase 1 studies are not uncommon (24.6 %). When a protocol required tumor or host analyte is not required, most screen failures are due to out of protocol-specified range for chemistry or the development of an interval medical issue. Screen failure rates were increased when patients had longer travel distances and fewer prior lines of systemic chemotherapy.


Subject(s)
Clinical Trials, Phase I as Topic , Patient Selection , Antineoplastic Agents/therapeutic use , Drugs, Investigational/therapeutic use , Female , Humans , Male , Neoplasms/drug therapy
20.
J Biomed Opt ; 17(4): 046008, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22559686

ABSTRACT

High-content cell imaging based on fluorescent protein reporters has recently been used to track the transcriptional activities of multiple genes under different external stimuli for extended periods. This technology enhances our ability to discover treatment-induced regulatory mechanisms, temporally order their onsets and recognize their relationships. To fully realize these possibilities and explore their potential in biological and pharmaceutical applications, we introduce a new data processing procedure to extract information about the dynamics of cell processes based on this technology. The proposed procedure contains two parts: (1) image processing, where the fluorescent images are processed to identify individual cells and allow their transcriptional activity levels to be quantified; and (2) data representation, where the extracted time course data are summarized and represented in a way that facilitates efficient evaluation. Experiments show that the proposed procedure achieves fast and robust image segmentation with sufficient accuracy. The extracted cellular dynamics are highly reproducible and sensitive enough to detect subtle activity differences and identify mechanisms responding to selected perturbations. This method should be able to help biologists identify the alterations of cellular mechanisms that allow drug candidates to change cell behavior and thereby improve the efficiency of drug discovery and treatment design.


Subject(s)
Histocytochemistry/methods , Image Processing, Computer-Assisted/methods , Microscopy, Fluorescence/methods , Transcription, Genetic , Drug Discovery , Fluorescent Dyes/analysis , Fluorescent Dyes/metabolism , Genes, Reporter , HCT116 Cells , Humans , Luminescent Proteins/analysis , Luminescent Proteins/genetics , Luminescent Proteins/metabolism
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