Micro and nanotechnology for cancer treatment

Thesis (Ph. D. in Biomedical Engineering)--Harvard-MIT Program in Health Sciences and Technology, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 92-101).Cancer is responsible for over 7.6 million deaths worldwide; the majority of patients fail to respond to drugs or become resistant over time. In order to gain a better understanding of drug efficacy in patients, we developed three diagnostic technologies to address limitations in sample acquisition and improve the scale and sensitivity of current cancer diagnostic tools. In the first section, we describe a hybrid magnetic and size sorting microfluidic device that isolates rare circulating tumor cells from peripheral blood. The self-assembled magnetic sorter creates strong magnetic fields and effectively removes leukocytes tagged with magnetic nanoparticles. The size sorting region retains the remaining cells in single cell capture sites, while allowing small red blood cells to pass through 5pm gaps. The device achieves over 103 enrichment, up to 96% recovery of cancer cells and allows for on-chip molecular profiling. In the second section we use a magnetic nanoparticle decorated with small molecule drugs to assay target expression and drug binding in mock clinical samples of cancer cells spiked into whole blood. Specifically, we modify a PARP inhibitor (Olabarib) and conjugate it to a dextran coated iron oxide nanoparticle. We measure the presence of the drug nanosensor based on the change in T2 relaxation time using a miniaturized, handheld NMR sensor for point-of-care diagnosis. In the final section, we detail a photocleavable DNA barcoding method for understanding treatment response via multiplexed profiling of cancer cells. We validate our method with a 94 marker panel on different cell lines with varying treatments, showing high correlations to gold standard methods such as immunofluorescence and flow cytometry. Furthermore, we demonstrate single cell sensitivity, and identify a number of expected biomarkers in response to cell treatments. Finally, we demonstrate the potential of our method to help in clinical monitoring of patients by examining intra- and inter-patient heterogeneity, and by correlating pre and post-treatment tumor profiles to patient response. Together, we show how these technologies can help overcome clinical limitations and expedite advancements in cancer treatment.by Adeeti UllalPh.D.in Biomedical Engineerin

Imaging Therapeutic PARP Inhibition In Vivo through Bioorthogonally Developed Companion Imaging Agents12

A number of small-molecule poly (ADP-ribose) polymerase (PARP) inhibitors are currently undergoing advanced clinical trials. Determining the distribution and target inhibitory activity of these drugs in individual subjects, however, has proven problematic. Here, we used a PARP agent for positron emission tomography-computed tomography (PET-CT) imaging (18F-BO), which we developed based on the Olaparib scaffold using rapid bioorthogonal conjugation chemistries. We show that the bioorthogonal 18F modification of the parent molecule is simple, highly efficient, and well tolerated, resulting in a half maximal inhibitory concentration (IC50) of 17.9 ± 1.1 nM. Intravital imaging showed ubiquitous distribution of the drug and uptake into cancer cells, with ultimate localization within the nucleus, all of which were inhibitable. Whole-body PET-CT imaging showed tumoral uptake of the drug, which decreased significantly, after a daily dose of Olaparib. Standard 18F-fludeoxyglucose imaging, however, failed to detect such therapy-induced changes. This research represents a step toward developing a more generic approach for the rapid codevelopment of companion imaging agents based on small-molecule therapeutic inhibitors

Ascites analysis by a microfluidic chip allows tumor-cell profiling

Ascites tumor cells (ATCs) represent a potentially valuable source of cells for monitoring treatment of ovarian cancer as it would obviate the need for more invasive surgical biopsies. The ability to perform longitudinal testing of ascites in a point-of-care setting could significantly impact clinical trials, drug development, and clinical care. Here, we developed a microfluidic chip platform to enrich ATCs from highly heterogeneous peritoneal fluid and then perform molecular analyses on these cells. We evaluated 85 putative ovarian cancer protein markers and found that nearly two-thirds were either nonspecific for malignant disease or had low abundance. Using four of the most promising markers, we prospectively studied 47 patients (33 ovarian cancer and 14 control). We show that a marker set (ATC[subscript dx]) can sensitively and specifically map ATC numbers and, through its reliable enrichment, facilitate additional treatment-response measurements related to proliferation, protein translation, or pathway inhibition.Grant P50CA086355Grant R01EB004626Grant R01EB010011Grant P01-CA139980Grant U54-CA151884Grant K12CA087723-11A1Grant DOD W81XWH-11-1-070

Nanoparticle-Mediated Measurement of Target–Drug Binding in Cancer Cells

Responses to molecularly targeted therapies can be highly variable and depend on mutations, fluctuations in target protein levels in individual cells, and drug delivery. The ability to rapidly quantitate drug response in cells harvested from patients in a point-of-care setting would have far reaching implications. Capitalizing on recent developments with miniaturized NMR technologies, we have developed a magnetic nanoparticle-based approach to directly measure both target expression and drug binding in scant human cells. The method involves covalent conjugation of the small-molecule drug to a magnetic nanoparticle that is then used as a read-out for target expression and drug-binding affinity. Using poly(ADP-ribose) polymerase (PARP) inhibition as a model system, we developed an approach to distinguish differential expression of PARP in scant cells with excellent correlation to gold standards, the ability to mimic drug pharmacodynamics <i>ex vivo</i> through competitive target–drug binding, and the potential to perform such measurements in clinical samples