We reported the synthesis and characterization of dual-responsive poly(N-isopropylacrylamide-acrylamide-chitosan) (PAC)-coated magnetic nanoparticles (MNPs) for controlled and targeted drug delivery and imaging applications. The PAC-MNPs size was about 150 nm with 70% iron mass content and excellent superparamagnetic properties. PAC-MNPs loaded with anti-cancer drug doxorubicin showed dual-responsive drug release characteristics with the maximum release of drugs at 40 °C (~78%) than at 37 °C (~33%) and at pH of 6 (~55%) than at pH of 7.4 (~28%) after 21 days. Further, the conjugation of prostate cancer-specific R11 peptides increased the uptake of PAC-MNPs by prostate cancer PC3 cells. The dose-dependent cellular uptake of the nanoparticles was also significantly increased with the presence of 1.3 T magnetic field. The nanoparticles demonstrated cytocompatibility up to concentrations of 500 μg/ ml when incubated over a period of 24 h with human dermal fibroblasts and normal prostate epithelial cells. Finally, pharmacokinetic studies indicated that doxorubicin-loaded PAC-MNPs caused significant prostate cancer cell death at 40 °C than at 37 °C, thereby confirming the temperature-dependent drug release kinetics and in vitro therapeutic efficacy. Future evaluation of in vivo therapeutic efficacy of targeted image-guided cancer therapy using R11-PAC-MNPs will reinforce a significant impact of the multifunctional PAC-MNPs on the future drug delivery systems.

Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers and demands effective targeted therapeutic strategies. In this meta-analysis study, we aim to identify significantly mutated genes and regulatory pathways to help us better understand the progression of SCLC and to identify potential biomarkers. Besides ranking genes based on their mutation frequencies, we sought to identify statistically significant mutations in SCLC with the MutSigCV software. Our analysis identified several genes with relatively low mutation frequency, including PTEN, as highly significant (p<0.001), suggesting these genes may play an important role in the progression of SCLC. Our results also indicated mutations in genes involved in the axon guidance pathways likely play an important role in SCLC progression. In addition, we observed that the mutation rate was significantly higher in samples with RB1 gene mutated when compared to samples with wild type RB1, suggesting that RB1 status has significant impact on the mutation profile and disease progression in SCLC.

One of fundamental challenges in cancer studies is that varying molecular characteristics of different tumor types may lead to resistance to certain drugs. As a result, the same drug can lead to significantly different results in different types of cancer thus emphasizing the need for individualized medicine. Individual prediction of drug response has great potential to aid in improving the clinical outcome and reduce the financial costs associated with prescribing chemotherapy drugs to which the patient’s tumor might be resistant. In this paper we develop a network based classifier (NBC) method for predicting sensitivity of cell lines to anticancer drugs from transcriptome data. In the literature, this strategy has been used for predicting cancer types. Here, we extend it to estimate sensitivity of cells from different tumor types to various anticancer drugs. Furthermore, we incorporate domain specific knowledge such as the use of apoptotic gene list and clinical dose information in our method to impart biological significance to the prediction. Our experimental results suggest that our network based classifier (NBC) method outperforms existing classifiers in estimating sensitivity of cell lines for different drugs.

Mutations in tp53 are thought to be one of the most common mechanisms by which cancer cells evade tumor suppression. Yet the exact mechanism of tumor suppression by P53 remains to be fully understood. The transcription factor P53 is activated in response to oncogenic stresses and exerts distinct anti-proliferative functions based on the stressor and cell type. Although numerous mammalian ChIP-Seq studies have identified thousands of P53 binding sites, the functionality of these binding sites remains to be established. To study how P53 binding following DNA damage differs between cell types, we performed comparisons between P53 ChIP-Seq data from Drosophila embryos at different developmental stages and a Drosophila cell line (Kc167). Differential expression analysis using RNA-Seq indicated that at an early stem cell-like developmental stage of Drosophila embryos there is P53-dependent induction of pro-apoptotic genes in response to irradiation but not in the later differentiated stages. We aim to establish functionally significant P53 binding sites by combining ChIP-Seq and RNA-Seq data from Drosophila embryos as well as Kc167. The functional significance of these binding sites will be identified by CRISPR-Cas9–mediated genome editing. Preliminary genome-wide motif analysis studies also exhibited that homotypic clustering of P53 consensus motifs is associated with P53 binding. We will also perform comparison studies of DNA damage-induced P53 binding in humans, mice and flies to identify analogous patterns. Preliminary studies revealed that a majority of the P53 binding sites are located at the repetitive regions of the Drosophila genome, especially the Long terminal repeats (LTRs) and Long interspersed nuclear elements (LINEs) as seen previously in mammals by other groups including Botcheva et al and Chang et al. P53 has been known to regulate the expression of retrotransposons and maintain genetic stability by keeping the number of repeats in control. We further aim to see if the functions carried out by P53 differ between repetitive vs. non-repetitive binding regions in Drosophila. This comparative genomics study will help identify the functionally significant P53 binding sites thus further our understanding of tumor suppression by P53. The knowledge obtained from this study will also be valuable in devising novel strategies to restore P53 function in cancers. Citation Format: Varsha Sundaresan, Ying Li, Benedetto DiCiaccio, Victor T. Lin, Adrian A. Acuna Higaki, Nicole F. Pelletier, Jessica T. Cheung, Lei Zhou. Elucidating the factors determining P53 binding and transcriptomic response to DNA damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5367.

Torque is the 3rd key of occlusion, described by Andrews. Achieving ideal torque is one of the most difficult and critical procedures performed during orthodontic treatment. A simple and easy method was used to construct a composite torquing cantilever which provides stability and maintains a high moment: force ratio for a single tooth to achieve labial or lingual root torque during finishing and detailing.

Cancer is considered to be a genetic disease characterized by sequential accumulation of mutations. Recent studies have provided evidence that epigenetic changes and regulatory sequence mutations could also dysregulate oncogenes and tumor suppressors. As a transcription factor, P53 is activated in response to oncogenic stress and exerts distinct anti-proliferative functions based on the stressor and cell type. Though a number of ChIP-Seq studies have identified thousands of P53 binding sites in mammalian genomes, the functionality of these binding sites remains to be established. In addition, we know little about what controls stress and cell context specific binding profile of P53. Traditionally, mutations in the coding regions of p53 have been extensively studied to gain insights on its role in cancer and to identify strategies to restore the functions of p53 in cancer cells. We hypothesize that mutations in or epigenetic silencing of functionally important P53 binding sites play an important role in tumorigenesis as well. Since functional regulatory regions tend to be more evolutionarily conserved, in this project we propose using a comparative genomics approach to identify functional P53 binding sites and determine if these regions are involved in tumorigenesis. In order to study how P53 binding following DNA damage differs between cell types, we aim to perform comparison between P53 ChIP-Seq data generated in our lab from Drosophila embryos at different developmental stages and a cell line (Kc167) as well as published datasets from mammalian stem cells and differentiated cells. Differential expression analysis using RNA-Seq exhibited that at an early stem cell-like stage there is P53-dependent induction of pro-apoptotic genes in response to DNA damage but not in the differentiated stages. We are seeking to establish functionally significant P53 binding sites by combining ChIP-Seq data and gene expression data obtained using RNA-Seq. The importance of these binding sites will be verified by CRISPR-Cas9 -mediated genome editing. We will also perform comparison studies of DNA damage-induced P53 binding in human, mouse and Drosophila to identify analogous patterns. Knowledge gained from this study will help us to understand the role of non-coding regulatory regions in tumorigenesis, and predict patient response to apoptosis inducing therapeutic agents. It may also lead to novel strategies to restore cellular sensitivity to chemotherapy or radiation. Citation Format: Varsha Sundaresan, Ying Li, Benedetto DiCiaccio, Victor T. Lin, Lei Zhou. A comparative genomics approach to understanding the control of cell context dependent P53 binding [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 391. doi:10.1158/1538-7445.AM2017-391

TPS2680 Background: RTX-224 is a genetically engineered off-the-shelf, allogeneic red blood cell that expresses the costimulatory molecule 4-1BB ligand (4-1BBL) and cytokine interleukin-12 (IL-12) on the cell surface. The use of 4-1BB and IL-12 agonists for cancer immunotherapy has been limited due to systemic toxicities. Unlike agonist antibodies and recombinant cytokines, which are distributed systemically, Red Cell Therapeutics, such as RTX-224, are restricted to the vasculature and spleen, which may limit toxicities previously observed with agonist 4-1BB monoclonal antibodies and recombinant IL-12. RTX-224 is designed to be a broad immune agonist of both adaptive and innate responses that activates and expands effector and memory CD8+ and CD4+ T cells, cytotoxic natural killer (NK) cells and produces inflammatory cytokines and chemokines, leading to enhanced antigen presentation. In preclinical studies, the combined activation of both adaptive and innate immune responses by the murine surrogate of RTX-224 led to antitumor activity while the restricted biodistribution improved the safety profile. Methods: The RTX-224-01 study is a Phase 1/2, first-in-human, multi-center, dose-escalation and expansion study of RTX-224 in patients with relapsed or refractory urothelial cancer, squamous cell carcinoma of the head and neck, non-small cell lung cancer, triple negative breast cancer and cutaneous melanoma. Safety, tolerability, pharmacokinetics and pharmacodynamics and anti-tumor activity of RTX-224 will be assessed. Approximately 28 patients will be enrolled across dose level cohorts to identify the recommended Phase 2 dose (RP2D). The starting dose is 100 million (1x108) cells administered intravenously every 3 weeks (Q3W) and the dose will be escalated by half-log increments following a Bayesian logarithmic regression model (BLRM) with overdose control. Following RP2D selection, each of the 5 expansion cohorts will enroll approximately 20 patients. Pharmacodynamic and exploratory biomarker studies correlative to clinical response will be evaluated on peripheral blood and paired tumor biopsies. Multiple technologies will be employed to profile the innate and adaptive responses following RTX-224 treatment. The study is open and enrolling patients in Phase 1. Clinical trial information: NCT05219578.