Ritonavir - A Novel Multidrug Resistance Modulator in Cancer Chemotherapy and Ocular Neovascular Diseases

Title from PDF of title page, viewed on July 15, 2015Dissertation advisor: Ashim K. MitraVitaIncludes bibliographic references (pages 195-222)Thesis (Ph.D.)--School of Pharmacy and Department of Chemistry. University of Missouri--Kansas City, 2014Multidrug resistance (MDR), a clinical outcome characterized by subtherapeutic intracellular drug concentration, is one of the predominant factors limiting effective cancer chemotherapy. Several possible mechanisms and molecular alterations have been implicated in the development of MDR, including activation of efflux transporters and metabolizing enzymes in response to therapeutic agents. Therefore, the primary objective of my dissertation project is to develop strategies for overcoming drug resistance in cancer chemotherapy. Human adenocarcinoma cells (LS-180) were treated for 72 hours with vinblastine alone and in the presence of ritonavir. The expression of efflux transporters (MDR1 and MRP2), metabolizing enzyme (CYP3A4) and nuclear hormone receptor (PXR) was induced in response to vinblastine. This overexpression was completely neutralized when cells were cotreated with ritonavir. Uptake of [3H] lopinavir and Vivid™ assay further confirmed the functional activity of transcribed genes upon cotreatment. Reduced cell proliferation, migration and increased apoptosis of cancer cells were further indicative of enhanced activity of chemotherapeutics (doxorubicin, paclitaxel, tamoxifen and vinblastine) in the presence of ritonavir. Combination therapy of anticancer drug with ritonavir may overcome drug resistance by neutralizing overexpression of efflux transporters and metabolizing enzymes. Hypoxia leading to neovascularization has also been implicated in the development of MDR and ocular neovascular diseases. Despite introduction of novel therapeutics, treatment of retinal disorders remains challenging, possibly due to complex nature of hypoxia signaling. This study demonstrates for the first time that hypoxic conditions may alter expression of efflux and influx transporters in retinal pigment epithelial (RPE) cells. These findings suggest that hypoxia may further alter disposition of ophthalmic drugs. Inhibiting this signaling mechanism with an already approved therapeutic molecule may have promising antiangiogenic role with fewer side effects. Our studies (quantitative PCR, immunoblot analysis, ELISA and angiogenic assay) have demonstrated that ritonavir inhibits the expression of hypoxia-inducible factor-1α (HIF-1α) mediated vascular endothelial growth factor (VEGF) expression in RPE cells probably via inhibition of PI3K/AKT pathway. This inhibition may reduce retinal neovascularization. These findings shed new light on the possibility of incorporating ritonavir in the treatment regimen of ocular angiogenic diseases. Although many inhibitors of HIF-1α are in clinical trials, additional benefit of using ritonavir is that it has been given to HIV patients with relatively low toxicity. The process of traditional drug development could be fast tracked since ritonavir is clinically approved for human use. However, further preclinical and clinical experiments are necessary to determine the repositioning of ritonavir in the treatment of ocular neovascular diseasesMechanisms of drug resistance in cancer chemotherapy: Coordinated role and regulation of efflux transporters and metabolizing enzymes -- Differential effect of MDR1 and MRP2 in cellular translocation of gemifloxacin -- PXR mediated induction of efflux transporters by fluoroquinolones: a possible mechanism for development of multidrug resistance -- Rotonavir: a novel therapeutic for overcoming drug resistance in cancer chemotherapy -- Hypoxia-inducible factor 1 (HIF-1): a potential target intervention in ocular neovascular diseases -- Molecular expression and functional activity of efflux and influx transporters in hypoxia induced retinal pigment epithelial cells -- Ritonavir inhibits HIF-1a mediated VEGF expression in retinal pigment epithelial cells -- Summary and recommendations -- Appendi

Pharmacokinetic aspects of retinal drug delivery

Drug delivery to the posterior eye segment is an important challenge in ophthalmology, because many diseases affect the retina and choroid leading to impaired vision or blindness. Currently, intravitreal injections are the method of choice to administer drugs to the retina, but this approach is applicable only in selected cases (e.g. anti-VEGF antibodies and soluble receptors). There are two basic approaches that can be adopted to improve retinal drug delivery: prolonged and/or retina targeted delivery of intravitreal drugs and use of other routes of drug administration, such as periocular, suprachoroidal, sub-retinal, systemic, or topical. Properties of the administration route, drug and delivery system determine the efficacy and safety of these approaches. Pharmacokinetic and pharmacodynamic factors determine the required dosing rates and doses that are needed for drug action. In addition, tolerability factors limit the use of many materials in ocular drug delivery. This review article provides a critical discussion of retinal drug delivery, particularly from the pharmacokinetic point of view. This article does not include an extensive review of drug delivery technologies, because they have already been reviewed several times recently. Instead, we aim to provide a systematic and quantitative view on the pharmacokinetic factors in drug delivery to the posterior eye segment. This review is based on the literature and unpublished data from the authors' laboratory.Peer reviewe

Identification of High-risk and Low-risk Groups among Men Who Chew Tobacco through Artificial Neural Networks (ANN) and Support Vector Machines (SVM)

The National Health and Nutrition Examination Survey (NHANES) is a survey research program conducted by the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC), an agency of the United States Department of Health and Human Services (HHS) of the federal government. It aims to assess the health and nutritional status of adults and children in the United States, and to track changes over time. The survey combines interviews and physical examinations. The objective of this project was to select a peer-reviewed article that used the NHANES data set, recreate the specific data set, repeat the analysis, and use a machine learning algorithm different from that one utilized in the paper to analyze the data. We chose the article “Chewing Tobacco: Who Uses and Who Quits? Findings from NHANES III, 1988–1994” by Beth Howard-Pitney and Marilyn A. Winkleby (American Journal of Public Health 2002, Vol 92, No. 2, 250-256). The paper aims to identify high-risk and low-risk groups among men who chew tobacco through a classification tree algorithm. We retrieved and filtered data from NAHNES III as per the analysis in the paper. The filtered data constitutes a sample size of 4969 men, 1866 non-Hispanic white, 1533 non-Hispanic black, and 1578 Mexican-American. The analysis was carried out on men of ages between 25 and 64. The classification tree outcome to classify high-risk and low-risk subgroups is compared to Artificial Neural Network (ANN) and Support Vector Machine (SVM) results

Synthesis of fluorinated 2-phenyl-4-quinolones from pyrrole-2,3-diones

A series of substituted 2-phenyl-4-quinolones 8-11 have been synthesized in good yields via ash vacuum thermolysis (FVT) of 1-aryl-4-cyano-5-phenylpyrrole-2,3-diones 7a-e and 1-aryl-4-methoxycarbonyl-5-phenylpyrrole-2,3-diones 7f-j. The pyrrolediones 7 were prepared from amines 3 and benzoylacetonitriles 5a-e or methyl 3-arylamino-3-phenylprop-2-enoates 5f-j

Hand Gesture Recognition and Conversion to Speech for Speech Impaired

The primary method of interaction between individuals is communication. In the case of speech-impaired people, the communication between them and normal people is not understandable by the latter as the former communicates through gestures and sign language. In the case of speech-impaired. Today, the Internet of Things (IoT) can be used for gesture recognition and to convert gestures into audible speech. In this project, a prototype is created such that the gesture or the sign language that is communicated is recognized by the flex sensors connected to the fingertips of a plain glove. The ESP32 microcontroller recognizes the gesture and converts it into the text format and this text format is updated onto the Google Firebase and is converted to speech form thus producing the text onto the OLED display sensor and the converted speech for communication in the mobile application Kodular Companion

Performance Comparison of Depth Limited Search and A* Algorithm: A Case Study

Search algorithms are an essential component of many artificial intelligence applications. Depth Limited Search and A* Search are two prominent search algorithms that have been widely used in various domains, including robotics, game playing, and natural language processing. The research paper presents an overview of these two algorithms, their architecture, pros and cons, and the areas of their application. A detailed comparison of these two algorithms in terms of their performance, efficiency, and effectiveness in solving various search problems is also analysed. Finally, the paper presents a case study for two approaches. Experimental results depicted that after repetitive execution of each algorithm and graph data, it was detected that while the A-star search was able to find the cheaper cost almost always, Depth Limited Search was able to find the route faster with limited node visits

Smart Parking Assistant: Integrating Ultrasonic Sensors and IoT for Enhanced Driver Experience

Parking Assistant is a solution that assists drivers to park their vehicles safely, using a variety of sensors that are installed strategically, such that the entire parking process is safe and easy. Sometimes drivers tend to hit the wall with their vehicles, because they cannot see what is in their blind spots or underestimate how far the wall is from their back. The garage might also be sometimes be too dark to safely park the vehicle. Therefore, building a system that can assist drivers by constantly notifying the distance between the back of the car and the wall, and can control the lighting can help reduce this risk, and assist them to park their vehicles safely. An ultrasonic sensor, such as the HC0SR04 can detect the distance from the sensor to a distant object, can be used for this purpose. A safe limit can be supplied to the program, and if the vehicle is found to be closer than the safe limit, then the driver is notified about the risk through the buzzer. Also, using relays, an automated garage automation system can be created, such that electricals in the garage can be controlled through a simple mobile application