Aptamer-Nanoparticle Bioconjugates for Drug Delivery

Drug delivery systems traditionally relied on passive diffusion mechanisms for targeting and releasing of therapeutically active molecules. The major problems associated with traditional delivery are poor specificity and dose-limited toxicity. Nanoparticles have found applicability in the development of novel drug delivery systems by easily overcoming toxicity problem. However, specificity of delivery has remained as a challenge. Developments in the methods of reaching to targeted tissue have lead to new and improved drug delivery platforms. Recently, active targeting has been incorporated by cell specific ligands such as antibodies, lectins, growth factor receptors. More recently, aptamers gained popularity in construction of novel actively targeted drug delivery systems (Ozalp et al., 2011). Considerable proportions of aptamer-based delivery systems have been incorporated to a variety of nanomaterials in order to improve their specific targeting properties (Chen et al., 2011; Zhou et al., 2011)

Molecular imaging targets in prostate cancers with neuroendocrine gene signature

The main treatment option for castration-resistant prostate cancer (CRPC) is androgen receptor pathway inhibition (ARPI). Selection pressure and lineage plasticity of ARPI could lead to neuroendocrine (NE) differentiation of prostate cancer (PC), promoting the more prevalent subtype of CRPC which is termed treatment-induced neuroendocrine prostate cancer (NEPC) or t-NEPC. Treatment options for NEPC are limited to platinum- and cisplatin-based combinations and median survival of NEPC patients is much lower than patients with CRPC. Early identification of NEPC and novel targeting options could be valuable. The transmembrane protein prostate-specific membrane antigen (PSMA) is an appealing target for molecular imaging and therapy of PC since it is over-expressed in a majority of PC tumors and metastatic lesions. Targeting PSMA is feasible by a wide variety of radio-ligands. The PSMA ligands can also be labeled with therapeutic radionuclides which can irradiate PSMA-expressing cells. Despite the positive implications of PSMA for many forms of advanced AdPC there are clinical reports supporting that PSMA-targeted imaging is not able to delineate NEPC tumors. Previous clinical reports indicate that PCs with a phenotype related to NE tumors can be more responsive to imaging by 18F-Fluorodeoxyglucose (FDG) rather than PSMA-targeting radioligands. In this work, we evaluated the association between NE gene signature and FDG uptake-associated genes including glucose transporters (GLUTs) and hexokinases, with the goal of providing a genomic signature to explain the reported FDG-avidity of PSMA-suppressed tumors. We use data mining approaches, cell lines and patient-derived xenograft (PDX) models to study the levels of 14 members of the SLC2A family (encoding GLUT proteins), 4 members of the hexokinase family (genes: HK1 to 3 and GCK) and PSMA (FOLH1 gene) following AR-inhibition and in correlation with NE hallmarks. Also, we characterize a NE-like PC (NELPC) subset among a cohort of primary and metastatic PC samples with no NE histopathology. We measured glucose uptake in a NE-induced in vitro model and a zebrafish model by non-radioactive imaging of glucose uptake using fluorescent glucose bioprobe, GB2-Cy3. This work demonstrates that a NE gene signature associates with differential expression of genes encoding GLUT and hexokinase proteins. In NELPC, elevated expression of GCK (encoding glucokinase protein) and decreased expression of SLC2A12 correlated with earlier biochemical recurrence. In tumors treated with AR-inhibitors, enhanced expression of GCK and low expression of SLC2A12 correlated with NE histopathology and PSMA gene suppression. GLUT12-suppression and enhanced expression of glucokinase were observed in NE-induced PC cell lines and PDX models. A higher glucose uptake was confirmed in low-PSMA tumors using a GB2-Cy3 probe in a zebrafish model. In summary, a NE gene signature in NEPC and NELPC associates with a distinct transcriptional profile of GLUTs and HKs. In transcriptomic level, PSMA-suppression correlates with GLUT12-suppression and glucokinase-upregulation. Alteration of FDG uptake-associated genes correlated positively with higher glucose uptake in AR and PSMA-suppressed tumors. Zebrafish xenograft tumor models are an accurate and efficient pre-clinical method for monitoring non-radioactive glucose uptake

Biomolecule-functionalized nanoformulations for prostate cancer theranostics

Background Even with the advancement in the areas of cancer nanotechnology, prostate cancer still poses a major threat to men’s health. Nanomaterials and nanomaterial-derived theranostic systems have been explored for diagnosis, imaging, and therapy for different types of cancer still, for prostate cancer they have not delivered at full potential because of the limitations like in vivo biocompatibility, immune responses, precise targetability, and therapeutic outcome associated with the nanostructured system. Aim of Review Functionalizing nanomaterials with different biomolecules and bioactive agents provides advantages specificity towards cancerous tumors, improved circulation time, and modulation of the immune response leading to early diagnosis and targeted delivery of cargo at the site of action. Key Scientific Concepts of Review In this review, we have emphasized the classification and comparison of various nanomaterials based on biofunctionalization strategy and source of biomolecules such that it can be used for possible translation in clinical settings and future developments. This review highlighted the opportunities for embedding highly specific biological targeting moieties (antibody, aptamer, oligonucleotides, biopolymer, peptides, etc.) on nanoparticles which can improve the detection of prostate cancer-associated biomarkers at a very low limit of detection, direct visualization of prostate tumors and lastly for its therapy. Lastly, special emphasis was given to biomimetic nanomaterials which include functionalization with extracellular vesicles, exosomes and viral particles and their application for prostate cancer early detection and drug delivery. The present review paves a new pathway for next-generation biofunctionalized nanomaterials for prostate cancer theranostic application and their possibility in clinical translation

Mechanogrowth factor (IGF-1Ec) and flourescent nanoparticles in colorectal cancer

The IGF-1 axis was an area of significant interest in cancer therapy following promising preclinical studies but led to disappointing clinical trials. Further scrutinization of this pathway is, therefore, warranted. The IGF-1 axis has been demonstrated to inhibit autophagy via the Akt/PI3K pathway and induce autophagy via the ERK pathway. Autophagy has been associated with chemotherapy resistance in tumour cells. My work in this thesis involved investigating the expression of an iso-form of IGF-1 referred to as IGF1-Ec or Mechanogrowth Factor (MGF) in colorectal cancer tissues and polyps with immunohistochemistry. Further work was done with fluorescent nanoparticles which have exciting potential to improve the diagnostic yield of investigations including colonosco-py, improve immunohistochemistry assessment of tissue biopsies and help in surgery with in-traoperative delineation of tumours. In addition, I investigated the relationship between autopha-gy and apoptosis with a view towards developing a model for further work in investigating the ef-fect of MGF in autophagy. Semi-quantitative immunohistochemistry for MGF on colonic tissues including normal, polyp and cancer tissues demonstrated a significantly higher expression of MGF in colonic polyps (with higher expression with worsening dysplasia, p=0.001) and cancer compared to normal colon tissues (p<0.001). Semiconductor CdTe quantum dots and gold nanoparticles were synthesised and conju-gated to the MGF peptide and antibody. Gold nanoparticles were successfully characterised with immunodots and applied to the HT29 and SW620 colorectal cancer cell lines and to tissues includ-ing normal, colon cancer and polyp tissues reflecting the results from conventional immunohisto-chemistry. Autophagy inducers were administered to the cell lines HT29 and SW620 and inhibited with the use of Bafilomycin and 3-MA. Immunohistochemistry for LC3B was used to confirm the induction of autophagy, and cell viability studies were used to demonstrate significantly increased cell viability with autophagy induction and significant reduction of cell viability with inhibition of autophagy (p<0.01 at 24 hours). This model can be subjected to the application of MGF and assess its effects on cell viability. MGF is overexpressed in colonic polyps and cancer with low levels of expression in normal colon tissues offering an opportunity for the use of fluorescent gold nanoparticles to augment polyp and cancer detection in colonoscopy and intraoperative tumour delineation

A Magnetic Bead-Based Sensor for the Quantification of Multiple Prostate Cancer Biomarkers.

Novel biomarker assays and upgraded analytical tools are urgently needed to accurately discriminate benign prostatic hypertrophy (BPH) from prostate cancer (CaP). To address this unmet clinical need, we report a piezeoelectric/magnetic bead-based assay to quantitate prostate specific antigen (PSA; free and total), prostatic acid phosphatase, carbonic anhydrase 1 (CA1), osteonectin, IL-6 soluble receptor (IL-6sr), and spondin-2. We used the sensor to measure these seven proteins in serum samples from 120 benign prostate hypertrophy patients and 100 Gleason score 6 and 7 CaP using serum samples previously collected and banked. The results were analyzed with receiver operator characteristic curve analysis. There were significant differences between BPH and CaP patients in the PSA, CA1, and spondin-2 assays. The highest AUC discrimination was achieved with a spondin-2 OR free/total PSA operation--the area under the curve was 0.84 with a p value below 10(-6). Some of these data seem to contradict previous reports and highlight the importance of sample selection and proper assay building in the development of biomarker measurement schemes. This bead-based system offers important advantages in assay building including low cost, high throughput, and rapid identification of an optimal matched antibody pair

Recent Advancements in Aptamer-bioconjugates: Sharpening Stones for Breast and Prostate Cancers Targeting

Breast and prostate cancers are common types of cancers with various strategies, such as chemotherapy and radiotherapy, for their therapy. Since these methods have undesired side effects and poor target affinity, neoteric strategies—known as aptamer-based smart drug delivery systems (SDDSs)—have been developed in recent years to overcome the obstacles of current treatment, and investigated for a clinical trial. The high affinity and versatility of aptamers for binding to the corresponding targets make them highly noticeable agents in the drug delivery domains. In addition to their exceptional benefits, aptamers are able to overcome tumor resistance because of their high selectivity and low toxicity. Furthermore, aptamers can conjugate with various drugs, nanoparticles and antibodies and effectively deliver them to the specific breast and prostate cells. This review highlights the current researches in aptamer-conjugate developments for targeting breast and prostate cancers, with the special focus on the nanoparticle-aptamer bioconjugates, systematic evolution of ligands by exponential enrichment (SELEX) system and SDDS, especially cutting-edge articles from 2008 to present. Finally, the future prospects and challenges are described

Beyond epithelial circulating tumour cells (CTCs) : establishing important methods for CTC isolation and analysis

This thesis has demonstrated the various applications for antibody-based CTC capture, extending beyond conventional methods. We reported the inclusion of EMT-markers for detection and characterisation of EMT-CTCs in the ovarian cancer setting. This methodological advancement may prove a critical step in understanding the role EMT plays in CTC formation, metastasis and potentially therapeutic resistance. In addition, we explored integration of electron microscopy methods into CTC sample processing, allowing for ultrastructure analysis of CTCs and improving the tools to help understand CTC biology. Finally, we explored antibody-based CTC isolation methods in the melanoma setting with additional biomarker PD-L1 detection, enabling real-time monitoring of therapy response to PD-1 inhibitors. Overall, the knowledge gained from this thesis will aid the CTC research field from three different perspectives: (1) The clinical perspective: capitalize on CTC detection by adding important biomarker detection that may indicate response to therapy; (2) The technical perspective: demonstrating feasibility of integrating electron microscopy sample preparation into CTC analyses; (3) The biological perspective: establishing EMT detection in a range of cancers

Current status of nanotechnology in urology

Nanotechnology has been investigated for its applications in medicine. The objective of this review was to summarize the current applications of nanotechnology in Urology. A systematic search of literature was performed and relevant articles were analyzed with specific reference to applications in Urology. Nanotechnology has applications in diagnostic urology like in uroimaging using nanoparticles and nanosensors. It has therapeutic applications in infections, malignancies, genetic disease using targeted drug delivery, gene transfers, nano device-based manipulations etc. Nanotechnology has many applications in Urology. More efforts are required to make these applications practically feasible and affordable

The Role of Rankl in Prostate Cancer Progression and Bone Metastasis

This study focused on the role of RANKL in prostate cancer EMT progression and metastasis. Activation of RANK, a receptor activator of NF-kB, by its ligand RANKL, in a paracrine manner is responsible for osteoclast differentiation and bone remodeling. RANK activation in cancer cells, however, is thought to be promoted by both autocrine and paracrine mechanisms because RANKL has been shown to be derived from either tumor or its microenvironment, such as osteoblasts, infiltrating inflammatory cells and stromal fibroblasts. In the present study, we demonstrated that autocrine and paracrine RANKL-RANK signaling could be responsible for driving prostate cancer bone metastasis by promoting epithelial to mesenchymal transition (EMT). We further characterized a novel converging RANKL-c-Met signaling network in which the activation of RANKL was found to promote the expression of both RANKL and c-Met in an autocrine manner in prostate cancer cells. The induced RANKL and c-Met in prostate cancer cells is biologically functional and contributes to increased osteoclastogenesis, epithelial to mesenchymal transition (EMT), cell motility, migration and invasion and conferred bone and soft tissue metastases. Remarkably, RANKL expression by 1,000 prostate cancer cells can provoke bone and soft tissue metastases of a “dormant” population of prostate cancer cells which by themselves failed to form tumors and colonize mouse skeleton, suggesting RANKL can serve as a factor in “reawakening” cancer dormancy to initiate the re-growth and metastasis of cancer cells. We also showed that RANKL-induced RANKL feed-forward autocrine regulation is mediated through cMyc transactivation, allowing the establishment of a “vicious cycle” further promoting prostate cancer growth and metastasis. The converging RANKL-c-Met signaling network is therefore a novel target that could be further manipulated for delaying the lethal progression of castration-resistant human prostate cancer bone metastasis

Magnetic Nanoformulations for Prostate Cancer

Magnetic nanoparticles (MNPs) play a vital role for improved imaging applications. Recently, a number of studies demonstrate MNPs can be applied for targeted delivery, sustained release of therapeutics, and hyperthermia. Based on stable particle size and shape, biocompatibility, and inherent contrast enhancement characteristics, MNPs have been encouraged for pre-clinical studies and human use. As a theranostic platform development, MNPs need to balance both delivery and imaging aspects. Thus, this review provides significant insight and advances in the theranostic role of MNPs through the documentation of unique magnetic nanoparticles used in prostate cancer, their interaction with prostate cancer cells, in vivo fate, targeting, and biodistribution. Specific and custom-made applications of various novel nanoformulations in prostate cancer are discussed