An Avidity-Based PD-L1 Antagonist Using Nanoparticle-Antibody Conjugates for Enhanced Immunotherapy

Upregulation of programmed death ligand 1 (PD-L1) allows cancer cells to evade antitumor immunity. Despite tremendous efforts in developing PD-1/PD-L1 immune checkpoint inhibitors (ICIs), clinical trials using such ICIs have shown inconsistent benefits. Here, we hypothesized that the ICI efficacy would be dictated by the binding strength of the inhibitor to the target proteins. To assess this, hyperbranched, multivalent poly(amidoamine) dendrimers were employed to prepare dendrimer-ICI conjugates (G7-aPD-L1). Binding kinetics measurements using SPR, BLI, and AFM revealed that G7-aPD-L1 exhibits significantly enhanced binding strength to PD-L1 proteins, compared to free aPD-L1. The binding avidity of G7-aPD-L1 was translated into in vitro efficiency and in vivo selectivity, as the conjugates improved the PD-L1 blockade effect and enhanced accumulation in tumor sites. Our results demonstrate that the dendrimer-mediated multivalent interaction substantially increases the binding avidity of the ICIs and thereby improves the antagonist effect, providing a novel platform for cancer immunotherapy.

Multi-modal liquid biopsy platform for cancer screening: screening both cancer-associated rare cells and cancer cell-derived vesicles on the fabric filters for a reliable liquid biopsy analysis

Circulating tumor cells (CTCs) are receiving a great amount of scientific interest as a diagnostic biomarker for various types of cancer. Despite the recent progress in the development of highly sensitive CTC isolation devices, post-capture analysis of CTCs is still hindered by technical challenges associated with their rarity. Herein, we present a multi-modal CTC screening platform which is capable to analyze CTCs and CTC-derived extracellular vesicles (EVs), simultaneously from a single sample. Cytochalasin B (CB) treatment promotes cells to release large number of EVs from their surface, as demonstrated by CB-treated cells (5 µg/mL for 3 h) secreting 3.5-fold more EVs, compared to the non-treated cells. CB further generates 1.7-fold more EVs from the cells captured on our CTC filtration device (the fabric filter), compared to those from the cell culture flasks, owing to its multiple pore structure design which reduces the non-specific binding of EVs. Both CB-treated cancer cells and CB-induced EVs are found to overexpress tumor-associated markers, demonstrating a potential for the development of CTC dual-screening platform. Collectively, the results presented in this study reveal that our multi-modal cancer screening platform can synergistically improve the reliability and efficacy of the current CTC analysis systems.

Abstract 410: Quantification and downstream analysis of circulating tumor cells isolated using CapioCyteTM liquid biopsy

Background: Circulating tumor cells (CTCs) have great potential as biomarkers for the diagnosis and prognosis of many cancers. The CapioCyteTM chip isolates live CTCs through a unique combination of biomimetic cell rolling and nanoparticle-mediated multivalent immunorecognition. Recently-published work reported the highly sensitive and specific CTC capture from 24 patients in a pilot study [Myung et al., Clinical Cancer Research 2018, 24(11):2439-2547]. Here, we report results from additional cohorts of patients and demonstrate downstream analysis of captured CTCs.

Methods: Peripheral blood samples were collected from patients undergoing radiotherapy (RT) (n=12; oligometastic n = 5, head and neck cancer n = 1, non small cell lung cancer n = 2, prostate cancer n = 3, cervical cancer n = 1) or immunotherapy (n=4). Samples were processed the next day by CapioCyteTM chips designed for the immunoisolation cells expressing epithelial cell adhesion molecule (EpCAM), human epidermal growth factor-2 (HER-2), and epidermal growth factor receptor (EGFR). Captured CTCs were identified by immunocytochemistry as containing round nuclei, positive expression of cytokeratin, and negative expression of CD45. Select samples were recovered from the capture surface and submitted for single cell gene expression assays (RNASeq) using 10X Genomics Chromium barcoding and Illumina next-generation sequencing.

Results: Immunocytochemical staining identified CTCs in all pre-treatment blood samples from patients undergoing RT (mean 95 CTC/ml whole blood, SE 54, range 4-680) and immunotherapy (mean 70 CTC/ml whole blood, SE 16, range 39-104). CTC counts decreased with time points collected during and post-treatment, consistent with other measures of treatment progress. Single cell RNASeq confirmed the presence of tumor-derived cells in select samples and, importantly, demonstrated the ability to conduct downstream analysis of CTCs isolated on the CapioCyteTM chip.

Conclusions: The CapioCyteTM chip effectively captures CTCs for quantification and downstream analysis requiring viable cells such as RNASeq. The liquid biopsy technology has great potential to contribute to diagnosis and personalized treatment of cancer.

Citation Format: Michael J. Poellmann, Jiyoon Bu, Dominic Moon, Kyle Wagner, Andrew Z. Wang, Seungpyo Hong. Quantification and downstream analysis of circulating tumor cells isolated using CapioCyteTM liquid biopsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 410.

Post-debulking circulating tumor cell as a poor prognostic marker in advanced stage ovarian cancer: A prospective observational study

Circulating tumor cells (CTCs) have received enormous attention as a novel biomarker in various malignant diseases. We investigated the clinical association between the presence of perioperative CTCs and survival outcomes in women with ovarian cancer. In a total of 30 women who were scheduled to undergo a surgical treatment for ovarian cancer, peripheral blood samples were obtained before and after surgery. CTCs were isolated and counted using the optimized tapered-slit filter (TSF) platform. The association between the presence of perioperative CTCs and tumor features was evaluated. The impact of the presence of perioperative CTCs on progression-free survival (PFS) and overall survival (OS) rates were analyzed using a Kaplan-Meier method. The median age was 58 (range, 24-77) years, and the median follow-up period was 31.5 (range, 1-41) months. Overall, the CTC detection rate was not significantly different before and after surgery (76.7% vs 57.1%, P = .673). The presence of postoperative CTCs was not significantly associated with 3-year PFS (29.1% vs 58.3%, P = .130) and OS (84.4% vs 80.0%, P = .559) rates in the whole study population. In advanced stage, PFS rate in patients with postoperative CTCs had lower PFS rates than those without postoperative CTCs, although there was no statistical significance (18.8% vs 57.1%, P = .077). Postoperative CTC was more frequently detected in women who had lymph node involvement than those who did not (7/7 [100%] vs 3/10 [30.0%], P = .010). The presence of postoperative CTCs as detected using the TSF platform seems to be associated with poorer PFS rates in women with ovarian cancer of advanced stage. Further study with a larger population is warranted to validate our study findings.

Sub-lethal hyperthermia promotes epithelial-to-mesenchymal-like transition of breast cancer cells: implication of the synergy between hyperthermia and chemotherapy

Thermotherapy has demonstrated a potential to be an effective non-surgical technique to treat breast cancer.

Peptide-nanoparticle conjugates: a next generation of diagnostic and therapeutic platforms?

Peptide-nanoparticle conjugates (PNCs) have recently emerged as a versatile tool for biomedical applications. Synergism between the two promising classes of materials allows enhanced control over their biological behaviors, overcoming intrinsic limitations of the individual materials. Over the past decades, a myriad of PNCs has been developed for various applications, such as drug delivery, inhibition of pathogenic biomolecular interactions, molecular imaging, and liquid biopsy. This paper provides a comprehensive overview of existing technologies that have been recently developed in the broad field of PNCs, offering a guideline especially for investigators who are new to this field.

Would antioxidant-loaded nanoparticles present an effective treatment for ischemic stroke?

Ischemic stroke is a leading cause of death and disability worldwide and is in urgent need of new treatment options. The only approved treatment for stroke restores blood flow to the brain, but much of the tissue damage occurs during the subsequent reperfusion. Antioxidant therapies that directly address ischemia-reperfusion injury have shown promise in preclinical results. In this review, we discuss that reformulating antioxidant therapies as nanomedicine can potentially overcome the barriers that have kept these therapies from succeeding in the clinic. We begin by reviewing the pathophysiology of ischemic stroke with a focus on the effects of reperfusion injury. Next, we review nanotherapeutic systems designed to treat the disease with a focus on those addressing reperfusion injury. Mechanisms of passive and active transport required to traverse a blood–brain barrier are discussed. Finally, we conclude by outlining design parameters for potentially successful nanomedicines as front-line therapeutics for ischemic stroke.

[Identification of Methamphetamine Abuse and Selegiline Use： Chiral Analysis of Methamphetamine and Amphetamine in Urine]

OBJECTIVES

To study the content variation of selegiline and its metabolites in urine, and based on actual cases, to explore the feasibility for the identification of methamphetamine abuse and selegiline use by chiral analysis.

METHODS

The urine samples were tested by chiral separation and LC-MS/MS method using CHIROBIOTIC™ V2 chiral liquid chromatography column. The chiral analysis of methamphetamine and amphetamine were performed on the urine samples from volunteers of selegiline use and drug addicts whom suspected taking selegiline.

RESULTS

After 5 mg oral administration, the positive test time of selegiline in urine was less than 7 h. The mass concentrations of R（-）-methamphetamine and R（-）-amphetamine in urine peaked at 7 h which were 0.86 μg/mL and 0.18 μg/mL and couldn't be detected after 80 h and 168 h, respectively. The sources of methamphetamine and amphetamine in the urine from the drug addicts whom suspected taking selegiline were analysed successfully by present method.

CONCLUSIONS

The chiral analysis of methamphetamine and amphetamine, and the determination of selegiline's metabolites can be used to distinguish methamphetamine abuse from selegiline use.

High-purity capture and release of circulating exosomes using an exosome-specific dual-patterned immunofiltration (ExoDIF) device

We present a microfluidic device for the capture and release of circulating exosomes from human blood. The exosome-specific dual-patterned immunofiltration (ExoDIF) device is composed of two distinct immuno-patterned layers, and is capable of enhancing the chance of binding between the antibody and exosomes by generating mechanical whirling, thus achieving high-throughput exosome isolation with high specificity. Moreover, follow-up recovery after the immuno-affinity based isolation, via cleavage of a linker, enables further downstream analysis. We verified the performance of the present device using MCF-7 secreted exosomes and found that both the concentration and proportion of exosome-sized vesicles were higher than in the samples obtained from the conventional exosome isolation kit. We then isolated exosomes from the human blood samples with our device to compare the exosome level between cancer patients and healthy donors. Cancer patients show a significantly higher exosome level with higher selectivity when validating the exosome-sized vesicles using both electron microscopy and nanoparticle tracking analysis. The captured exosomes from cancer patients also express abundant cancer-associated antigens, the epithelial cell adhesion molecule (EpCAM) on their surface. Our simple and rapid exosome recovery technique has huge potential to elucidate the function of exosomes in cancer patients and can thus be applied for various exosome-based cancer research studies.

Circulating tumor cells in the differential diagnosis of adnexal masses

The aim of this study was to evaluate circulating tumor cell (CTC) detection in the differential diagnosis of adnexal masses. A total of 87 preoperative women with an indeterminate adnexal mass were prospectively enrolled. Preoperative diagnostic modalities including CTC detection, risk of ovarian malignancy algorithm, risk of malignancy index, and computed tomography or magnetic resonance imaging were compared. Forty-three (49.4%) benign tumors, 13 (14.9%) borderline malignant masses, and 31 (35.7%) cancers were pathologically confirmed. Forty-nine (56.3%) cases were positive for CTCs: 19/43 (44.2%) benign, 10/10 (100%) early-stage, and 14/21 (66.7%) advanced-stage cancer. CTC detection had sensitivities of 77.4%, 100%, and 100% for benign vs. all stage cancer (n = 74), benign vs. stage I–II cancer (n = 53), and benign vs. stage I cancer (n = 49), respectively. CTC detection had a specificity of 55.8% across all comparisons. The sensitivities of the other modalities assayed were decreased in stage I–II cancer and stage I cancer vs. benign masses. Receiver operating characteristic curves showed that CTCs, of which the area under the curve was modest in all stage cancer (0.655), had the widest area under the curve among the evaluated modalities in stage I–II cancer and stage I cancer (0.768 for both). In conclusion, our study findings suggest that preoperative CTCs could have a substantial role in differentiating early stage cancer from benign tumors for adnexal masses.

Abstract 4306: Combined effects of chemotherapy to reduce metastasis caused by insufficient hyperthermia

Hyperthermia therapy is one of the most widely studied non-surgical methods for breast tumors, which eliminates tumor by inducing acute stress on tumor cells. However, it has been extensively known that the viability of the tumor cells is highly influenced by the applied temperature. Insufficient thermal stress during hyperthermia treatments may alter tumor microenvironment by promoting epithelial to mesenchymal-like transition (EMT) and as a result, enhancing the outgrowth of residual tumor cells. Therefore, cells that have survived from sublethal thermal stress and experienced EMT may cause substantial clinical problems. In this case, hyperthermia requires additional therapy in order to promote cell death of more invasive tumor cells that have resisted to the thermal stimulus. In this study, we confirmed that the co-treatment of chemotherapy with hyperthermia may overcome the phenotypical transition caused by insufficient heat treatment. After exposing breast cancer cells (MCF-7) into two different temperature conditions (42°C and 47°C) for an hour, we have verified that 10.51 ± 1.71% and 18.27 ± 10.66% of cells experienced apoptosis or necrosis when the cells were exposed to 42°C and 47°C, respectively. At the same time, cancer cells showed higher invasiveness, spear-like morphology, and enhanced migratory behaviors as the exposed temperature increases, which is mainly shown among the cells that have experienced EMT. Further western blot assay and quantitative real-time polymerase chain reaction (qRT-PCR) using mesenchymal marker (vimentin) and epithelial marker (E-cadherin) also support that the mesenchymal-like phenotype has been highly increased on the cells that have resisted to the thermal stress. However, when chemotherapy was conducted after the heat treatment, cell viability was highly reduced. Paclitaxel (11.7 nM), cisplatin (3.3 μM), and combination of two anticancer drugs were treated for 24 hours on the cells that have been exposed to different temperatures, respectively. As a result, death rate of tumor cells has increased from 11.31 to 66.69%. Especially, when paclitaxel and cisplatin were co-treated, the death rate was up to 73.75 ± 4.37% after cells were exposed to 47°C. In conclusion, cancer cells that have survived from insufficient hyperthermia showed high potential to promote metastasis or recurrence but additional chemotherapy can successfully reduce the side effects induced by insufficient hyperthermia treatment.

Citation Format: Tae Hee Lee, Jiyoon Bu, Byoung Hyuck Kim, Young Jun Kim, Yoon-Tae Kang, Jung Eun Moon, Young-Ho Cho. Combined effects of chemotherapy to reduce metastasis caused by insufficient hyperthermia [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 4306. doi:10.1158/1538-7445.AM2017-4306

Enhancement of isolation sensitivity for the viable heterogeneous circulating tumor cells swelled by hypo-osmotic pressure

We have applied a hypo-osmotic gradient for enhancing the isolation of viable heterogeneous circulating tumor cells.

Dual-patterned immunofiltration (DIF) device for the rapid efficient negative selection of heterogeneous circulating tumor cells

The analysis of circulating tumor cells (CTCs) is an emerging field for estimating the metastatic relapse and tumor burden of cancer patients. However, the isolation of CTCs is still challenging due to their ambiguity, rarity, and heterogeneity. Here, we present an anti-CD45 antibody based dual-patterned immunofiltration (DIF) device for the enrichment of heterogeneous CTC subtypes by effective elimination of leukocytes. Our uniquely designed dual-patterned layers significantly enhance the binding chance between immuno-patterns and leukocytes due to the fluidic whirling and the increased binding sites, thus achieving superior negative selection in terms of high-throughput and high purity. From the experiments using lung cancer cells, 97.07 ± 2.79% of leukocytes were eliminated with less than 10% loss of cancerous cells at the flow rate of 1 mL h^-1. To verify the device as a potential diagnostic tool, CTCs were collected from 11 cancer patients' blood and an average of 283.3 CTC-like cells were identified while less than 1 CTC-like cells were found from healthy donors. The samples were also analyzed by immunohistochemistry and the reverse transcription polymerase chain reaction to identify their heterogeneous characteristics. These remarkable results demonstrate that the present device could help to understand the unknown properties or undiscovered roles of CTCs with a non-biased view.

Chemotherapy uptake and wait times in early-stage non-small-cell lung cancer

BACKGROUND

Treatment uptake and elapsed times along the care path have emerged as potential quality indicators for cancer care delivery. This retrospective study examined changes in adjuvant chemotherapy uptake and elapsed times along the care path for patients in 2005 and in 2007 who had early-stage non-small-cell lung cancer (nsclc) and who underwent curative-intent surgery in Nova Scotia, Canada.

METHODS

All patients who underwent curative-intent surgery for stages i-iii nsclc in the two years of interest were included. Logistic regression and general linear models were used to examine factors associated with chemotherapy uptake patterns and, at various resolutions (low, intermediate, high), elapsed times between all care events in the care path.

RESULTS

In the 223 patients who underwent curative-intent surgery (108 in 2005, 115 in 2007), several factors were associated with uptake patterns and elapsed times. Cohort year (2007 vs. 2005) was not associated with referral to medical oncology [odds ratio (or): 1.05; 95% confidence interval (ci): 0.51 to 2.15; p = 0.905], but it was associated with less treatment after referral (or: 0.34; 95% ci: 0.11 to 1.00; p = 0.057) and less overall uptake (or: 0.35; 95% ci: 0.13 to 0.95; p = 0.040). Patients were referred sooner to medical oncology in 2007 than in 2005 (21 days vs. 35 days, p = 0.008), but experienced longer waits between consultation and chemotherapy delivery (18 days vs. 7 days, p = 0.001).

CONCLUSIONS

Significant differences were observed in care patterns over time. Frequent monitoring of care patterns at high resolution may optimize insights into emerging trends within cancer care systems.

A modified fractal zone plate with extended depth of focus in spectral domain optical coherence tomography

In optical coherence tomography (OCT) systems, there is a trade-off between the depth of focus (DOF) and lateral resolution when conventional lenses are used. We propose a new method that employs a modified fractal generalized zone plate (MFraGZP) combined with a conventional lens to improve the trade-off effect, with an extended DOF of about 2.5 mm (14 times larger) while the lateral resolution is maintained at ~9.5 μm. As an example, images of the calibration microspheres are obtained and demonstrated with the extended DOF in a spectral domain OCT system.

Manipulation of surface plasmon polaritons by phase modulation of incident light

Manipulation of surface plasmon polaritons (SPP) by phase modulation of incident light beams is proposed with analytical and numerical verifications when an optical vortex (OV) beam is employed as an example. Fundamental functionalities of a plasmonic chip such as in-plane focusing, coupling and multiplexing of SPP by sequentially varying the topological charge of OV beam are demonstrated. Complementary to the manually-controlled optical-path-different technique reported in literature, the proposed method reveals a direct phase transform from OV beam to SPP with dynamic and reconfigurable advantages.

Deterministic relief dielectric structures to realize phase modulation of surface-plasmon polaritons

We propose a modified effective-refractive-index model for the design of relief dielectric structures on a metal surface to realize phase modulation of surface-plasmon polaritons (SPPs). In this model, the length of the dielectric structure is optimized to reach phase shifting between the SPP waves transmitted through dielectric structure and those directly propagated with the consideration of SPP losses. Specifically, a one-dimensional dielectric Fresnel zone plate is designed by employing the proposed model to demonstrate phase modulation of SPPs for the highest focusing efficiency.