Detection of circulating tumor cells in patients with lung cancer using metallic micro-cavity array filter: A pilot study.

We have developed a metallic micro-cavity array filter and an automated detection system for capturing circulating tumor cells (CTCs). In this single institutional pilot study, we assessed the ability of this device to detect CTCs in patients with lung cancer at each stage. Patients diagnosed with lung cancer, undergoing planned surgery for lung cancer, or suspected of having lung cancer were recruited (40 recruited and 2 excluded). Blood samples were obtained from the patients and 3 ml whole blood was applied to the device without any preparation. The captured cells were stained to differentiate the nucleus, and determine cytokeratin and CD45 expression. Subsequently, two operators blinded to clinical information counted the number of CTCs. Sample collection was performed at the time of recruitment, before treatment and ~3 months after initial blood collection. CTC counts at recruitment were 1.4±0.4, 1.8±1.2, 1.3±0.6 and 7.4±5.1 (mean ± SE) in clinical stages I, II, III and IV, respectively. No significant difference was observed among the stages. These data indicated the ability of this device to detect CTCs at early or non-metastatic stages of lung cancer. Further research on a larger scale is needed for a more accurate assessment of the device, and research on the utility of captured cells remains a future challenge.

Clinical study designs and patient selection methods based on genomic biomarkers: Points-to-consider documents.

Recently, genomic biomarkers have been widely used clinically for prediction of the efficacy and safety of pharmacotherapy and diagnosis and prognosis of pathological conditions. Therefore, genomic biomarkers are anticipated to accelerate not only precision medicine for pharmacotherapy but also development of molecularly targeted drugs. Because the design of clinical studies involving biomarkers may differ from conventional clinical study designs, a concept paper focused on clinical studies and patient selection methods based on genomic biomarkers is desired to prompt innovative drug development. Thus, this concept paper aimed to compile and present current scientific information from the related guidelines regarding application of genomic biomarkers to clinical trials and studies for drug development. We hope that this concept paper will prompt the development of guidelines for biomarker application to drug development by industry, regulatory authorities, the medical profession, and academia.

Heterogeneous Expression of Programmed Death Receptor-ligand 1 on Circulating Tumor Cells in Patients With Lung Cancer.

BACKGROUND: Blockade of the programmed death receptor-1 (PD-1) pathway is effective against solid tumors including lung cancer. PD-ligand 1 (PD-L1) expression on tumor tissue serves as a predictive biomarker for the efficacy of PD-1 pathway blockade. Here, we evaluated the expression of PD-L1 on circulating tumor cells (CTCs) in patients with lung cancer. MATERIALS AND METHODS: Peripheral whole blood (3 mL) was collected from patients, and CTCs and PD-L1 expression were detected using a microcavity array (MCA) system. Immunohistochemistry for PD-L1 detection was also performed using matched tumor tissues. RESULTS: Sixty-seven patients with lung cancer were enrolled in the study between July 2015 and April 2016 at Wakayama Medical University Hospital. The characteristics of the patients were as follows: median age, 71 years (range, 39-86 years); male, 72%; stage II to III/IV, 14%/85%; non-small-cell lung cancer/small-cell lung cancer/other, 73%/21%/6%. CTCs were detected in 66 of 67 patients (median, 19; range, 0-115), and more than 5 CTCs were detected in 78% of patients. PD-L1-expressing CTCs were detected in 73% of patients, and the proportion score of PD-L1-expressing CTCs ranged from 3% to 100%, suggesting intra-patient heterogeneity of PD-L1 expression on CTCs. Tumor tissues were available from 27 patients and were immunostained for PD-L1, and no correlation was observed between tumor tissues and CTCs based on the proportion score (R2 = 0.0103). CONCLUSION: PD-L1 expression was detectable on CTCs in patients with lung cancer, and intra-patient heterogeneity was observed. No correlation was observed between PD-L1 expression in tumor tissues and CTCs.

Development of an automated size-based filtration system for isolation of circulating tumor cells in lung cancer patients.

Circulating tumor cells (CTCs), defined as tumor cells circulating in the peripheral blood of patients with solid tumors, are relatively rare. Diagnosis using CTCs is expected to help in the decision-making for precision cancer medicine. We have developed an automated microcavity array (MCA) system to detect CTCs based on the differences in size and deformability between tumor cells and normal blood cells. Herein, we evaluated the system using blood samples from non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC) patients. To evaluate the recovery of CTCs, preclinical experiments were performed by spiking NSCLC cell lines (NCI-H820, A549, NCI-H23 and NCI-H441) into peripheral whole blood samples from healthy volunteers. The recovery rates were 70% or more in all cell lines. For clinical evaluation, 6 mL of peripheral blood was collected from 50 patients with advanced lung cancer and from 10 healthy donors. Cells recovered on the filter were stained. We defined CTCs as DAPI-positive, cytokeratin-positive, and CD45-negative cells under the fluorescence microscope. The 50 lung cancer patients had a median age of 72 years (range, 48-85 years); 76% had NSCLC and 20% had SCLC, and 14% were at stage III disease whereas 86% were at stage IV. One or more CTCs were detected in 80% of the lung cancer patients (median 2.5). A comparison of the CellSearch system with our MCA system, using the samples from NSCLC patients, confirmed the superiority of our system (median CTC count, 0 versus 11 for CellSearch versus MCA; p = 0.0001, n = 17). The study results suggest that our MCA system has good clinical potential for diagnosing CTCs in lung cancer.

Calcilytics enhance sildenafil-induced antiproliferation in idiopathic pulmonary arterial hypertension.

Idiopathic pulmonary arterial hypertension (IPAH) is a progressive and fatal disease of the pulmonary artery resulting from currently unidentified etiology. IPAH is pathologically characterized as sustained vasoconstriction and vascular remodeling of the pulmonary artery. Phosphodiesterase type 5 (PDE5) inhibitors have been clinically used in the treatment of IPAH. Recently, we have shown that Ca(2+)-sensing receptor (CaSR) antagonists, or calcilytics, inhibit excessive cell proliferation of pulmonary arterial smooth muscle cells (PASMCs) from IPAH patients. In this study, the additive or synergistic effect of calcilytics on antiproliferation following PDE5 inhibition was examined in IPAH-PASMCs by MTT assay. Treatment with sildenafil blocked the excessive cell proliferation of IPAH-PASMCs in a concentration-dependent manner with an IC50 value of 16.9µM. However, sildenafil (0.03-100µM) did not affect the cell growth of PASMCs from normal subjects and patients with chronic thromboembolic pulmonary hypertension (CTEPH). Co-treatment with 0.3µM NPS2143, a calcilytic, additively enhanced the antiproliferative effect induced by sildenafil (3 or 30µM) in IPAH-PASMCs. Additionally, the inhibitory effect of calcilytics, NPS2143 or Calhex 231 (1 or 10µM), on excessive cell proliferation of IPAH-PASMCs was synergistic increased in the presence of 1µM sildenafil. Similar results were obtained by BrdU incorporation assay. These findings reveal that calcilytics additively/synergistically enhance the antiproliferative activity mediated by PDE5 inhibition, suggesting that a combination therapy of a PDE5 inhibitor with a calcilytic may be useful as a novel therapeutic approach for IPAH.

Characteristics of pharmacogenomics/biomarker-guided clinical trials for regulatory approval of anti-cancer drugs in Japan.

Pharmacogenomics (PGx) or biomarker (BM) has the potential to facilitate the development of safer and more effective drugs in terms of their benefit/risk profiles by stratifying population into categories such as responders/non-responders and high-/low-risks to drug-induced serious adverse reactions. In the past decade, practical use of PGx or BM has advanced the field of anti-cancer drug development. To identify the characteristics of the PGx/BM-guided clinical trials for regulatory approval of anti-cancer drugs in Japan, we collected information on design features of 'key trials' in the review reports of anti-cancer drugs that were approved after the implementation of the 'Revised Guideline for the Clinical Evaluation of Anti-cancer drugs' in April 2006. On the basis of the information available on the regulatory review data for the newly approved anti-cancer drugs in Japan, this article aims to explain the limitations and points to consider in the study design of PGx/BM-guided clinical trials.

Synthetic studies on glycosphingolipids from protostomia phyla: synthesis of glycosphingolipids from the parasite Schistosoma mansoni.

Synthetic access to three neutral glycosphingolipids from the parasite Schistosoma mansoni adult worm has been achieved. These structures differ significantly from those of other parasites and exhibit a unique structural motif termed "schisto-core" consisting of GalNAcbeta1-->4Glcbeta1-->sequence. We have synthesized glycosphingolipids, beta-D-GalNAcp-(1-->4)-beta-D-Glcp-(1-->1)Cer (1), beta-D-GlcNAcp-(1-->3)-beta-D-GalNAcp-(1-->4)-beta-D-Glcp-(1-->1)Cer (2) and beta-D-Galp-(1-->4)-beta-D-GlcNAcp-(1-->3)-beta-D-GalNAcp-(1-->4)-beta-D-Glcp-(1-->1)Cer (3).