千葉大学泌尿器科第1回同門会発表

BackgroundWhile programmed death 1 (PD-1) and programmed death-ligand 1 (PD-L1) checkpoint inhibitors have activity in a proportion of patients with advanced bladder cancer, strongly predictive and prognostic biomarkers are still lacking. In this study, we evaluated PD-L1 protein expression on circulating tumor cells (CTCs) isolated from patients with muscle invasive (MIBC) and metastatic (mBCa) bladder cancer and explore the prognostic value of CTC PD-L1 expression on clinical outcomes.MethodsBlood samples from 25 patients with MIBC or mBCa were collected at UCSF and shipped to Epic Sciences. All nucleated cells were subjected to immunofluorescent (IF) staining and CTC identification by fluorescent scanners using algorithmic analysis. Cytokeratin expressing (CK)+ and (CK)-CTCs (CD45-, intact nuclei, morphologically distinct from WBCs) were enumerated. A subset of patient samples underwent genetic characterization by fluorescence in situ hybridization (FISH) and copy number variation (CNV) analysis.ResultsCTCs were detected in 20/25 (80 %) patients, inclusive of CK+ CTCs (13/25, 52 %), CK-CTCs (14/25, 56 %), CK+ CTC Clusters (6/25, 24 %), and apoptotic CTCs (13/25, 52 %). Seven of 25 (28 %) patients had PD-L1+ CTCs; 4 of these patients had exclusively CK-/CD45-/PD-L1+ CTCs. A subset of CTCs were secondarily confirmed as bladder cancer via FISH and CNV analysis, which revealed marked genomic instability. Although this study was not powered to evaluate survival, exploratory analyses demonstrated that patients with high PD-L1+/CD45-CTC burden and low burden of apoptotic CTCs had worse overall survival.ConclusionsCTCs are detectable in both MIBC and mBCa patients. PD-L1 expression is demonstrated in both CK+ and CK-CTCs in patients with mBCa, and genomic analysis of these cells supports their tumor origin. Here we demonstrate the ability to identify CTCs in patients with advanced bladder cancer through a minimally invasive process. This may have the potential to guide checkpoint inhibitor immune therapies that have been established to have activity, often with durable responses, in a proportion of these patients

Inflammatory mechanism induced by natural and engineered silica particles in human-derived macrophages at low non-cytotoxic doses

Particle size, phase, and transition metals have all been implicated in natural and engineered silica-induced respiratory effects, as well as cellular interactions. However, efforts to unambiguously determine their role in the pro-inflammatory mechanism induction have been hampered due to the use of inhomogeneous samples, with incomplete characterization and the use of high cytotoxic doses. Here, engineered micro- and nano- sized silica particles, which are more homogenous in their materials properties and used in a variety of applications, were characterized and compared to natural silica at a realistic dose level. Natural (2 μm) and engineered silica particles (2 μm and 50 nm) were characterized and controlled for size, morphology, phase, iron presence, surface area, and aggregation. A novel lipid peroxidation-dependent pro-inflammatory mechanism due to the influence of iron, particle size, and phase was hypothesized for these particles under a low non-cytotoxic dose closer to a realistic exposure regime. It was observed that at a 1 μg/ml low non-cytotoxic dose of silica the presence or addition of iron, reduction of particle size, and crystalline phase of natural silica significantly increased superoxide (O2.-) and hydrogen peroxide (H2O2) production in the macrophages. This increase in O2.- and H2O2 production, further lead to phosphatidylcholine-specific phospholipase C (PC-PLC) - mediated inflammatory mediator or cytokine production in macrophages via lipid peroxidation and lipid raft disruption (large fraction sub-domains of plasma membrane involved in signal transduction). Addition of an iron chelator abrogated these responses, supporting the role of iron in the hypothesized mechanism. Activation of PC-PLC - induced inflammatory response was determined by using PC-PLC inhibitor, Tricychodecan-9-yl-xanthate, which blocked the inflammatory mediator production. Microscopy studies with cell-particle interaction revealed that particle size also influenced the uptake of silica particles in the macrophages mainly via phagocytosis, since binding and activation of membrane receptors and subsequent internalization is strongly dependent on nanoparticle size. Also, a high cytotoxic dose of 100 μg/ml showed macrophage particle overload for both particle sizes, with macrophage damage possibly leading to catastrophic release of inflammatory mediators that could obfuscate study of the normal inflammatory response, emphasizing the need for studies with realistic exposure doses. In summary, this work demonstrated the role of particle size, iron, and phase in a lipid raft dependent-inflammatory mechanism induced by particles at a realistic exposure dose via PC-PLC. It should lead to a better understanding of the mechanism and important parameters for the particle-induced inflammatory response of the lungs, and therefore, control of the respiratory effects caused by real-life exposure to natural and engineered particles

Measurement of copy number variation in single cancer cells using rapid-emulsification digital droplet MDA.

Uniform amplification of low input DNA is important for applications across biology, including single-cell genomics, forensic science, and microbial and viral sequencing. However, the requisite biochemical amplification methods are prone to bias, skewing sequence proportions and obscuring signals relating to copy number. Digital droplet multiple displacement amplification enables uniform amplification, but requires expert knowledge of microfluidics to generate monodisperse emulsions. In addition, existing microfluidic methods are tedious and labor intensive for preparing many samples. Here, we introduce rapid emulsification multiple displacement amplification, a method to generate monodisperse droplets with a hand-held syringe and hierarchical droplet splitter. While conventional microfluidic devices require >10 minutes to emulsify a sample, our system takes tens of seconds and yields data of equivalent quality. We demonstrate the approach by using it to accurately measure copy number variation in single cancer cells

Circulating Tumor Cells as Potential Biomarkers in Bladder Cancer

PurposeWe explored the diagnostic use of circulating tumor cells in patients with neoadjuvant bladder cancer using enumeration and next generation sequencing.Materials and methodsA total of 20 patients with bladder cancer who were eligible for cisplatin based neoadjuvant chemotherapy were enrolled in an institutional review board approved study. Subjects underwent blood draws at baseline and after 1 cycle of chemotherapy. A total of 11 patients with metastatic bladder cancer and 13 healthy donors were analyzed for comparison. Samples were enriched for circulating tumor cells using the novel IsoFlux™ System microfluidic collection device. Circulating tumor cell counts were analyzed for repeatability and compared with Food and Drug Administration cleared circulating tumor cells. Circulating tumor cells were also analyzed for mutational status using next generation sequencing.ResultsMedian circulating tumor cell counts were 13 at baseline and 5 at followup in the neoadjuvant group, 29 in the metastatic group and 2 in the healthy group. The concordance of circulating tumor cell levels, defined as low-fewer than 10, medium-11 to 30 and high-greater than 30, across replicate tubes was 100% in 15 preparations. In matched samples the IsoFlux test showed 10 or more circulating tumor cells in 4 of 9 samples (44%) while CellSearch® showed 0 of 9 (0%). At cystectomy 4 months after baseline all 3 patients (100%) with medium/high circulating tumor cell levels at baseline and followup had unfavorable pathological stage disease (T1-T4 or N+). Next generation sequencing analysis showed somatic variant detection in 4 of 8 patients using a targeted cancer panel. All 8 cases (100%) had a medium/high circulating tumor cell level with a circulating tumor cell fraction of greater than 5% purity.ConclusionsThis study demonstrates a potential role for circulating tumor cell assays in the management of bladder cancer. The IsoFlux method of circulating tumor cell detection shows increased sensitivity compared with CellSearch. A next generation sequencing assay is presented with sufficient sensitivity to detect genomic alterations in circulating tumor cells

Targeting CD46 for both adenocarcinoma and neuroendocrine prostate cancer

Although initially responsive to androgen signaling inhibitors (ASIs), metastatic castration-resistant prostate cancer (mCRPC) inevitably develops and is incurable. In addition to adenocarcinoma (adeno), neuroendocrine prostate cancer (NEPC) emerges to confer ASI resistance. We have previously combined laser capture microdissection and phage antibody display library selection on human cancer specimens and identified novel internalizing antibodies binding to tumor cells residing in their tissue microenvironment. We identified the target antigen for one of these antibodies as CD46, a multifunctional protein that is best known for negatively regulating the innate immune system. CD46 is overexpressed in primary tumor tissue and CRPC (localized and metastatic; adeno and NEPC), but expressed at low levels on normal tissues except for placental trophoblasts and prostate epithelium. Abiraterone- and enzalutamide-treated mCRPC cells upregulate cell surface CD46 expression. Genomic analysis showed that the CD46 gene is gained in 45% abiraterone-resistant mCRPC patients. We conjugated a tubulin inhibitor to our macropinocytosing anti-CD46 antibody and showed that the resulting antibody-drug conjugate (ADC) potently and selectively kills both adeno and NEPC cell lines in vitro (sub-nM EC50) but not normal cells. CD46 ADC regressed and eliminated an mCRPC cell line xenograft in vivo in both subcutaneous and intrafemoral models. Exploratory toxicology studies of the CD46 ADC in non-human primates demonstrated an acceptable safety profile. Thus, CD46 is an excellent target for antibody-based therapy development, which has potential to be applicable to both adenocarcinoma and neuroendocrine types of mCRPC that are resistant to current treatment

Real-Time Transferrin-Based PET Detects MYC-Positive Prostate Cancer

Noninvasive biomarkers that detect the activity of important oncogenic drivers could significantly improve cancer diagnosis and management of treatment. The goal of this study was to determine whether 68Ga-citrate (which avidly binds to circulating transferrin) can detect MYC-positive prostate cancer tumors, as the transferrin receptor is a direct MYC target gene. PET imaging paired with 68Ga-citrate and molecular analysis of preclinical models, human cell-free DNA (cfDNA), and clinical biopsies were conducted to determine whether 68Ga-citrate can detect MYC-positive prostate cancer. Importantly, 68Ga-citrate detected human prostate cancer models in a MYC-dependent fashion. In patients with castration-resistant prostate cancer, analysis of cfDNA revealed that all patients with 68Ga-citrate avid tumors had a gain of at least one MYC copy number. Moreover, biopsy of two PET avid metastases showed molecular or histologic features characteristic of MYC hyperactivity. These data demonstrate that 68Ga-citrate targets prostate cancer tumors with MYC hyperactivity. A larger prospective study is ongoing to demonstrate the specificity of 68Ga-citrate for tumors with hyperactive MYC.Implications: Noninvasive measurement of MYC activity with quantitative imaging modalities could substantially increase our understanding of the role of MYC signaling in clinical settings for which invasive techniques are challenging to implement or do not characterize the biology of all tumors in a patient. Moreover, measuring MYC activity noninvasively opens the opportunity to study changes in MYC signaling in patients under targeted therapeutic conditions thought to indirectly inhibit MYC. Mol Cancer Res; 15(9); 1221-9. ©2017 AACR