An Innovative Phase I Trial Design Allowing for the Identification of Multiple Potential Maximum Tolerated Doses with Combination Therapy of Targeted Agents

Treatment for cancer often involves combination therapies used both in medical practice and clinical trials. Korn and Simon listed three reasons for the utility of combinations: 1) biochemical synergism, 2) differential susceptibility of tumor cells to different agents, and 3) higher achievable dose intensity by exploiting non-overlapping toxicities to the host. Even if the toxicity profile of each agent of a given combination is known, the toxicity profile of the agents used in combination must be established. Thus, caution is required when designing and evaluating trials with combination therapies. Traditional clinical design is based on the consideration of a single drug. However, a trial of drugs in combination requires a dose-selection procedure that is vastly different than that needed for a single-drug trial. When two drugs are combined in a phase I trial, an important trial objective is to determine the maximum tolerated dose (MTD). The MTD is defined as the dose level below the dose at which two of six patients experience drug-related dose-limiting toxicity (DLT). In phase I trials that combine two agents, more than one MTD generally exists, although all are rarely determined. For example, there may be an MTD that includes high doses of drug A with lower doses of drug B, another one for high doses of drug B with lower doses of drug A, and yet another for intermediate doses of both drugs administered together. With classic phase I trial designs, only one MTD is identified. Our new trial design allows identification of more than one MTD efficiently, within the context of a single protocol. The two drugs combined in our phase I trial are temsirolimus and bevacizumab. Bevacizumab is a monoclonal antibody targeting the vascular endothelial growth factor (VEGF) pathway which is fundamental for tumor growth and metastasis. One mechanism of tumor resistance to antiangiogenic therapy is upregulation of hypoxia inducible factor 1α (HIF-1α) which mediates responses to hypoxic conditions. Temsirolimus has resulted in reduced levels of HIF-1α making this an ideal combination therapy. Dr. Donald Berry developed a trial design schema for evaluating low, intermediate and high dose levels of two drugs given in combination as illustrated in a recently published paper in Biometrics entitled “A Parallel Phase I/II Clinical Trial Design for Combination Therapies.” His trial design utilized cytotoxic chemotherapy. We adapted this design schema by incorporating greater numbers of dose levels for each drug. Additional dose levels are being examined because it has been the experience of phase I trials that targeted agents, when given in combination, are often effective at dosing levels lower than the FDA-approved dose of said drugs. A total of thirteen dose levels including representative high, intermediate and low dose levels of temsirolimus with representative high, intermediate, and low dose levels of bevacizumab will be evaluated. We hypothesize that our new trial design will facilitate identification of more than one MTD, if they exist, efficiently and within the context of a single protocol. Doses gleaned from this approach could potentially allow for a more personalized approach in dose selection from among the MTDs obtained that can be based upon a patient’s specific co-morbid conditions or anticipated toxicities.

Knowledge and Perception of the Role of Targeted Ultrasound in Detecting Down Syndrome Among a High Risk Population

The purpose of this study was to determine the perception and knowledge of targeted ultrasound in women who screen positive for Down syndrome in the first or second trimester, and to assess the perceived detection rate of Down syndrome by targeted ultrasound in this population. While several studies have reported patient perceptions’ of routine ultrasound, no study has specifically examined knowledge regarding the targeted ultrasound and its role in detecting Down syndrome. A targeted ultrasound is a special ultrasound during the second trimester offered to women who may be at a higher-than-average risk of having a baby with some type of birth defect or complication. The purpose of the ultrasound is to evaluate the overall growth and development of the baby as well as screen for birth defects and genetic conditions. Women under the age of 35 referred for an abnormal first or second trimester maternal serum screen to several Houston area clinics were asked to complete a questionnaire to obtain demographic and ultrasound knowledge information as well as assess perceived detection rate of Down syndrome by ultrasound. Seventy-seven women completed the questionnaire and participated in the study. Our findings revealed that women have limited background knowledge about the targeted ultrasound and its role in detecting Down syndrome. These findings are consistent with other studies that have reported a lack of understanding about the purpose of ultrasound examinations. One factor that seems to increase background knowledge about the targeted ultrasound is individuals having a higher level of education. However, most participants regardless of race, education, income, and exposure to targeted ultrasound information did not know the capabilities of a targeted ultrasound. This study confirmed women lack background knowledge about the targeted ultrasound and do not know enough about the technology to form a perception regarding its ability to detect Down syndrome. Additional studies to identify appropriate education techniques are necessary to determine how to best inform our patient population about targeted ultrasound.

Activation of heat shock and antioxidant responses by the natural product celastrol: transcriptional signatures of a thiol-targeted molecule.

Stress response pathways allow cells to sense and respond to environmental changes and adverse pathophysiological states. Pharmacological modulation of cellular stress pathways has implications in the treatment of human diseases, including neurodegenerative disorders, cardiovascular disease, and cancer. The quinone methide triterpene celastrol, derived from a traditional Chinese medicinal herb, has numerous pharmacological properties, and it is a potent activator of the mammalian heat shock transcription factor HSF1. However, its mode of action and spectrum of cellular targets are poorly understood. We show here that celastrol activates Hsf1 in Saccharomyces cerevisiae at a similar effective concentration seen in mammalian cells. Transcriptional profiling revealed that celastrol treatment induces a battery of oxidant defense genes in addition to heat shock genes. Celastrol activated the yeast Yap1 oxidant defense transcription factor via the carboxy-terminal redox center that responds to electrophilic compounds. Antioxidant response genes were likewise induced in mammalian cells, demonstrating that the activation of two major cell stress pathways by celastrol is conserved. We report that celastrol's biological effects, including inhibition of glucocorticoid receptor activity, can be blocked by the addition of excess free thiol, suggesting a chemical mechanism for biological activity based on modification of key reactive thiols by this natural product.

Alterations in content and localization of defensins in rat ileum and jejunum following ischemia-reperfusion. Specific peptides, in specific places, for specific jobs?

Objective: To determine alterations in quantities and distributions of natural antimicrobials following ischemia-reperfusion injury. We hypothesized that these compounds would be upregulated in areas of small intestine where changes in permeability and cellular disruption were likely and where protective mechanisms would be initiated. Methods: Rats with ischemia-reperfusion underwent superior mesenteric artery clamping and reperfusion. Shams were subjected to laparotomy but no clamping. Ileum and jejunum were harvested and sectioned, and subjected to fluorescence deconvolution microscopy for determinations of content and localization of rat beta defensins, 1, 2, 3; rat neutrophil protein-1; and cathelicidin LL-37. Modeling was performed to determine cellular location of antimicrobials. Results: Ischemia-reperfusion increased neutrophil defensin alpha (RNP-1) in jejunum; rat beta defensin 1 was increased 2-fold in ileal mucosa and slightly reduced in jejunal mucosa; rat beta defensin 2 was reduced by ischemia-reperfusion in ileum, but slightly increased in jejunum; rat beta defensin 3 was concentrated in the muscularis externa and myenteric plexus of the jejunum; ischemia-reperfusion did not alter cathelicidin LL-37 content in the small intestine, although a greater concentration was seen in jejunum compared with ileum. Conclusion: Ischemia-reperfusion injury caused changes in antimicrobial content in defined areas, and these different regulations might reflect the specific roles of jejunum versus ileum.

Targeted Multistage Delivery of Nanoparticles to the Bone Marrow

Bone marrow is a target organ site involved in multiple diseases including myeloproliferative disorders and hematologic malignancies and metastases from breast and prostate. Most of these diseases are characterized with poor quality of life, and the treatment options are only palliative due to lack of delivery mechanisms for systemically injected drugs which results in dose limitation to protect the healthy hematopoietic cells. Therefore, there is a critical need to develop effective therapeutic strategies that allow for selective delivery of therapeutic payload to the bone marrow. Nanotechnology-based drug delivery systems provide the opportunity to deliver drugs to the target tissue while decreasing exposure to normal tissues. E-selectin is constitutively expressed on the bone marrow vasculature, but almost absent in normal vessels, and therefore, E-selectin targeted drug delivery presents an ideal strategy for the delivery of therapeutic nanoparticles to the bone marrow. The objective of this study was to develop a novel bone marrow targeted multistage vector (MSV) via E-selectin for delivery of therapeutics and imaging agents. To achieve this goal, Firstly, an E-selectin thioaptamer (ESTA) ligand was identified through a two-step screening from a combinatorial thioaptamer library. Next, ESTA-conjugated MSV (ESTA-MSV) were developed and evaluated for their stability and binding to E-selectin expressing endothelial cells. Different types of nanoparticles including liposomes, quantum dots, and iron oxide nanoparticles were loaded into the porous structure of ESTA-MSV. In vivo targeting experiments demonstrated 8-fold higher accumulation of ESTA-MSV in the mouse bone marrow as compared to non-targeted MSV Furthermore, intravenous injection of liposomes loaded ESTA-MSV resulted in a significantly higher accumulation of liposome in the bone marrow space as compared to injection of non-targeted MSV or liposomes alone. Overall this study provides first evidence that E-selectin targeted multistage vector preferentially targets to bone marrow vasculature and delivers larger amounts of nanoparticles. This delivery strategy holds potential for the selective delivery of large amounts of therapeutic payload to the vascular niches in the bone marrow for the treatment of bone marrow associated diseases.

NOVEL AMINO ACID TRANSPORTER-TARGETED RADIOTRACERS FOR BREAST CANCER IMAGING

Breast cancer is the most common malignancy among women in the world. Its 5-year survival rate ranges from 23.4% in patients with stage IV to 98% in stage I disease, highlighting the importance of early detection and diagnosis. 18F-2-Fluoro-2-deoxy-glucose (18F-FDG), using positron emission tomography (PET), is the most common functional imaging tool for breast cancer diagnosis currently. Unfortunately, 18F-FDG-PET has several limitations such as poorly differentiating tumor tissues from inflammatory and normal brain tissues. Therefore, 18F-labeled amino acid-based radiotracers have been reported as an alternative, which is based on the fact that tumor cells uptake and consume more amino acids to sustain their uncontrolled growth. Among those radiotracers, 18F-labeled tyrosine and its derivatives have shown high tumor uptake and great ability to differentiate tumor tissue from inflammatory sites in brain tumors and squamous cell carcinoma. They enter the tumor cells via L-type amino acid transporters (LAT), which were reported to be highly expressed in many cancer cell lines and correlate positively with tumor growth. Nevertheless, the low radiosynthesis yield and demand of an on-site cyclotron limit the use of 18F-labeled tyrosine analogues. In this study, four Technetium-99m (99mTc) labeled tyrosine/ AMT (α-methyl tyrosine)-based radiotracers were successfully synthesized and evaluated for their potentials in breast cancer imaging. In order to radiolabel tyrosine and AMT, the chelators N,N’-ethylene-di-L-cysteine (EC) and 1,4,8,11-tetra-azacyclotetradecane (N4 cyclam) were selected to coordinate 99mTc. These chelators have been reported to provide stable chelation ability with 99mTc. By using the chelator technology, the same target ligand could be labeled with different radioisotopes for various imaging modalities for tumor diagnosis, or for internal radionuclide therapy in future. Based on the in vitro and in vivo evaluation using the rat mammary tumor models, 99mTc-EC-AMT is considered as the most suitable radiotracer for breast cancer imaging overall, however, 99mTc-EC-Tyrosine will be more preferred for differential diagnosis of tumor from inflammation.

APPLICATIONS OF EPHB4 RECEPTOR SPECIFIC PEPTIDES IN TARGETED CANCER IMAGING AND THERAPY

EphB4 receptors, a member of the largest family of receptor tyrosine kinases, are found over-expressed in a variety of tumors cells including glioma cells as well as angiogenic blood vessels. Noninvasive imaging of EphB4 could potentially increase early detection rates, monitor response to therapy directed against EphB4, and improve patient outcomes. Targeted delivery of EphB4 receptor specific peptide conjugated hollow gold nanoshells (HAuNS) into tumors has great potential in cancer imaging and photothermal therapy. In this study, we developed an EphB4 specific peptide named TNYL-RAW and labeled with radioisotope 64Cu and Cy5.5 dye. We also conjugate this specific peptide with hollow gold nanoshells (HAuNS) to evaluate targeted photothermal therapy of cancers. In vitro, 64Cu-DOTA-TNYL- RAW specifically bind to CT26 and PC-3M cells but not to A549 cells. In vivo, Small-animal PET/CT clearly showed the significant uptake of 64Cu-DOTA-TNYL-RAW in CT26 and PC-3M tumors but not in A549 tumors. Furthermore, µPET/CT and near-infrared optical imaging clearly showed the uptake of the dual labeled TNYL-RAW peptide in both U251 and U87 tumors in the brains of nude mice. In U251 tumors, Cy5.5-labeled peptide can bind to EphB4-expressing tumor blood vessels and tumors cells. But in U87 models, dual labeled peptide only could bind to tumor associated blood vessels. Also, Irradiation of PC-3M and CT-26 cell treated with TNYL-PEG-HAuNS nanopatilces with near-infrared (NIR) laser resulted in selective destruction of these cells in vitro. EphB4 targeted TNYL-PEG-HAuNS showed more photothermal killing effect on CT26 tumor model than PEG-HAuNS did. In summary, tumors with overexpression of EphB4 receptors can be noninvasively visualized by micro PET/CT with 64Cu labeled or dual labeled TNYL-RAW peptide. Targeted delivery of TNYL-RAW conjugated HAuNS into tumors can greatly improve the treatment effect of photothermal therapy. The information acquired with this study should be advantageous in improving diagnostics and future applications in photothermal ablation therapy in clinical.

Targeted cancer diagnosis with radiolabeled endostatin

Nuclear imaging is used for non-invasive detection, staging and therapeutic monitoring of tumors through the use of radiolabeled probes. Generally, these probes are used for applications in which they provide passive, non-specific information about the target. Therefore, there is a significant need for actively-targeted radioactive probes to provide functional information about the site of interest. This study examined endostatin, an endogenous inhibitor of tumor angiogenesis, which has affinity for tumor vasculature. The major objective of this study was to develop radiolabeled analogues of endostatin through novel chemical and radiochemical syntheses, and to determine their usefulness for tumor imaging using in vitro and in vivo models of vascular, mammary and prostate tumor cells. I hypothesize that this binding will allow for a non-invasive approach to detection of tumor angiogenesis, and such detection can be used for therapeutic monitoring to determine the efficacy of anti-angiogenic therapy. ^ The data showed that endostatin could be successfully conjugated to the bifunctional chelator ethylenedicysteine (EC), and radiolabeled with technetium-99m and gallium-68, providing a unique opportunity to use a single precursor for both nuclear imaging modalities: 99mTc for single photon emission computed tomography and 68Ga for positron emission tomography, respectively. Both radiolabeled analogues showed increased binding as a function of time in human umbilical vein endothelial cells and mammary and prostate tumor cells. Binding could be blocked in a dose-dependent manner by unlabeled endostatin implying the presence of endostatin receptors on both vascular and tumor cells. Animal biodistribution studies demonstrated that both analogues were stable in vivo, showed typical reticuloendothelial and renal excretion and produced favorable absorbed organ doses for application in humans. The imaging data provide evidence that the compounds quantitate tumor volumes with clinically-useful tumor-to-nontumor ratios, and can be used for treatment follow-up to depict changes occurring at the vascular and cellular levels. ^ Two novel endostatin analogues were developed and demonstrated interaction with vascular and tumor cells. Both can be incorporated into existing nuclear imaging platforms allowing for potential wide-spread clinical benefit as well as serving as a diagnostic tool for elucidation of the mechanism of action of endostatin. ^

Team: Bee Me. A formulative evaluation of a negative eating attitudes and behaviors primary prevention curriculum targeted at 5 th grade elementary school girls

Objective. To evaluate a school-based intervention aimed at the primary prevention of negative eating attitudes and behaviors among preadolescent girls, and to revise curriculum lessons based on quantitative and qualitative findings. ^ Intervention Design. A formative evaluation was conducted on four Team: Bee Me curriculum lessons at a Houston elementary school. Evaluation focused on program satisfaction and short-term effect on knowledge and eating attitudes and behaviors. ^ Results. Sixteen girls participated in the five-day project. Statistically significant improvements in overall knowledge were observed (p<0.05), however only modest changes were observed in eating attitudes and behaviors. Program satisfaction was high among student participants and the teacher who implemented it. Insight for future modifications to this program and for similar interventions was provided by the students and teacher. ^ Conclusions. This program led to positive trends in outcome variables; however longer and more intensive testing of this program is needed to better evaluate its effectiveness.^

Application of cell line based genomic predictors to predict response to targeted therapies in breast cancer

Cancer cell lines can be treated with a drug and the molecular comparison of responders and non-responders may yield potential predictors that could be tested in the clinic. It is a bioinformatics challenge to apply the cell line-derived multivariable response predictors to patients who respond to therapy. Using the gene expression data from 23 breast cancer cell lines, I developed three predictors of dasatinib sensitivity by selecting differentially expressed genes and applying different classification algorithms. The performance of these predictors on independent cell lines with known dasatinib response was tested. The predictor based on weighted voting method has the best overall performance. It correctly predicted dasatinib sensitivity in 11 out of 12 (92%) breast and 17 out of 23 (74%) lung cancer cell lines. These predictors were then applied to the gene expression data from 133 breast cancer patients in an attempt to predict how the patients might respond to dasatinib therapy. Two predictors identified 13 patients in common to be dasatinib sensitive. Sixty two percent of these cases are triple negative (ER-negative, HER2-negative and PR-negative) and 76% are double negative. The result is consistent with the findings from other studies, which identified a target population for dasatinib treatment to be triple negative or basal breast cancer subtype. In conclusion, we think that the cell line-derived dasatinib classifiers can be applied to the human patients. ^

Targeted immunization to protect infants against pertussis in the United States

Pertussis is an infectious disease caused by the bacteria Bordetella pertussis, and is associated with a serious respiratory infection, a prolonged cough, and can require hospitalization. A vaccine for adolescents and adults has been available since 2005. This paper examines one recommended immunization strategy to prevent pertussis among infants, called “cocooning.” The strategy focuses on creating immunity among adult caregivers so they serve as a protective cocoon to the newborns, who are too young to be vaccinated. This paper looks at relevant studies summarizing implementation of cocooning strategies and addresses the question – Does the research literature support the view of using cocooning as an effective strategy to prevent pertussis in infants? After exclusions, 8 studies remained for synthesis. The evidence shows that cocooning is complex strategy and the evidence is mixed when it comes to ensuring an increase in immunization of caregivers. ^

Investigating the effects of the 2007 Texas tobacco tax increase on the smoking behavior of adults

Smoking is major cause of premature mortality and morbidity in the United States. The health consequences of tobacco usage are increasingly concentrated in minority and lower socioeconomic groups. One of the most effective means of deterring tobacco consumption and generating revenue to fund prevention activities is the levying of excise taxes. In 2007 the state of Texas increased the excise tax on cigarettes by $1.00 per pack. This study sought to determine if there was a significant effect on smoking prevalence in the state by examining Behavioral Risk Factor Surveillance System (BRFSS) data for two years leading up to the tax increase-2005 and 2006- and two years post tax increase -2007 and 2008. Results were compared against a chi square distribution and three multiple logistic regression models were created to adjust for race/ethnicity, age, education and income. Results from this study show that there was not a significant decrease in smoking prevalence for most of the groups stratified by age, income and ethnicity. There was not a significant decrease in the younger adults aged 18-34 by income, ethnicity, or education. Smoking prevalence increased for some groups, e.g., Hispanic females. In the regression models, the tax effect was not significant. While overall prevalence decreased by 9%, there were not significant reductions among non-White or Hispanic survey participants. Taxed sales dropped by approximately 17% according to the Texas Comptroller. Without BRFSS data measuring daily cigarette consumption among current smokers, now not assessed, it is impossible to determine whether the discrepancy in reported prevalence and taxes sales is attributable to consumption of fewer cigarettes among smokers or tax avoidance.^

Increasing awareness of colorectal cancer screening through targeted exam room based video messages

Colorectal cancer (CRC) is the third largest cause of cancer death in the United States. While the disease burden is high, there are proven methods to screen for CRC and detect it at a stage that is amenable to cure. Patients with low health literacy have difficulty navigating the health care system and are at increased risk to not receive preventive care services such as colorectal cancer screening (CRCS). To address this need, an exam-room based video was developed to be played for patients in the privacy of the exam room, while they are waiting to be seen by their medical provider. In roughly 2 minutes, the video informs the patient about CRC and CRCS and how they can successfully complete CRCS. One of the key barriers to completing CRCS is the need to increase patients' knowledge and improve attitudes surrounding CRCS. This study examines the impact of the video on patients' knowledge and attitudes about CRC and CRCS in a medically underserved patient population in Houston, Texas. ^ Sixty-one patients presenting for routine medical care were enrolled in the study. Depending on their randomization, the patients either received routine information about CRC and CRCS or they watched the video. We found that the patients who did watch the video did have improvements in their knowledge and improved attitudes about CRC and CRCS. Future studies will be needed to examine whether the video improves the patients' completion of CRCS.^

Risk factors for diabetic retinopathy in Mexican Americans in Starr County, Texas

The prevalence of diabetes in Mexican Americans is disproportionately higher than in non-Hispanic whites. The rate of diabetic retinopathy resulting from prolonged diabetes is also greater in Mexican Americans than in non-Hispanic whites. A longitudinal study was carried out on data collected from Mexican Americans in Starr County, Texas to assess the association between socioeconomic and acculturation factors with diabetic retinopathy prevalence, incidence, and progression in those free of diabetic retinopathy or who had only early non-proliferative diabetic retinopathy. A multivariable analysis was done. ^ The incidence rate was 12.78 cases per year and the progression rate was 8.55 cases per year. The baseline characteristics of the population revealed that more people with occupations synonymous with lower income jobs like trade workers and machine operators had early non-proliferative diabetic retinopathy. A multivariable analysis revealed that those with early non-proliferative diabetic retinopathy were more likely to have been born in Mexico as compared to those free of diabetic retinopathy. Surprisingly, a multivariable analysis also showed that those that progressed in diabetic retinopathy disease status were more likely to have been employed as compared to those that did not. ^ This analysis reveals that Mexican Americans are heterogeneous in socioeconomic and acculturation factors that may be used to deter the incidence and progression of diabetic retinopathy severity. These findings could be targeted to create culturally sensitive intervention programs that will improve the detection and treatment of diabetic retinopathy in the work arena in addition to programs that will impact those that do not work. Workplace preventative health screenings and dissemination of language-specific informational brochures is warranted to curb the rates of progression in those employed. ^ A limitation of this study is the narrow surrogates used for assessing socioeconomic and acculturation status. To fully evaluate these variables, a study using a questionnaire with a multitude of surrogates for socioeconomic and acculturation factors should be employed.^

Predictive validity of the personal background and preparation survey and effectiveness of targeted interventions among health science community college students

Existing data, collected from 1st-year students enrolled in a major Health Science Community College in the south central United States, for Fall 2010, Spring 2011, Fall 2011 and Spring 2012 semesters as part of the "Online Navigational Assessment Vehicle, Intervention Guidance, and Targeting of Risks (NAVIGATOR) for Undergraduate Minority Student Success" with CPHS approval number HSC-GEN-07-0158, was used for this thesis. The Personal Background and Preparation Survey (PBPS) and a two-question risk self-assessment subscale were administered to students during their 1st-year orientation. The PBPS total risk score, risk self-assessment total and overall scores, and Under Representative Minority Student (URMS) status were recorded. The purpose of this study is to evaluate and report the predictive validity of the indicators identified above for Adverse Academic Status Events (AASE) and Nonadvancement Adverse Academic Status Events (NAASE) as well as the effectiveness of interventions targeted using the PBPS among a diverse population of health science community college students. The predictive validity of the PBPS for AASE has previously been demonstrated among health science professions and graduate students (Johnson, Johnson, Kim, & McKee, 2009a; Johnson, Johnson, McKee, & Kim, 2009b). Data will be analyzed using binary logistic regression and correlation using SPSS 19 statistical package. Independent variables will include baseline- versus intervention-year treatments, PBPS, risk self-assessment, and URMS status. The dependent variables will be binary AASE and NAASE status. ^ The PBPS was the first reliable diagnostic and prescriptive instrument to establish documented predictive validity for student Adverse Academic Status Events (AASE) among students attending health science professional schools. These results extend the documented validity for the PBPS in predicting AASE to a health science community college student population. Results further demonstrated that interventions introduced using the PBPS were followed by approximately one-third reduction in the odds of Nonadvancement Adverse Academic Status Events (NAASE), controlling for URMS status and risk self-assessment scores. These results indicate interventions introduced using the PBPS may have potential to reduce AASE or attrition among URMS and nonURMS attending health science community colleges on a broader scale; positively impacting costs, shortages, and diversity of health science professionals.^