Satomi Yagi

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.

Abstract 2257: Differential expression of PD-L1 on circulating tumor cells among patients with advanced lung cancer

Background and purpose: Immune-checkpoint blockade with anti-programmed death-1 (PD-1) antibodies is rapidly emerging for the treatment of human malignancies including lung cancer. Although programmed death-ligand 1 (PD-L1) has been studied as a predictive biomarker, detection and evaluation of PD-L1 expression level on tissue samples remain challenging due to its dynamic and unstable expression. Thus the diagnostic tool for real-time monitoring of PD-L1 expression is critically needed. Here, we assessed the expression pattern of PD-L1 on circulating tumor cells (CTCs) by using microcavity array (MCA) system in patients with advanced non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Experimental procedure: PD-L1 staining on CTCs was established using NSCLC cell lines H820, H441, A549 and H23 expressing varying levels of PD-L1 spiked in the peripheral blood obtained from healthy donors. For clinical evaluation, 3 ml of peripheral whole blood was collected from 20 advanced lung cancer patients prior to the initiation of chemotherapy and from 10 healthy donors. Cells were captured and immuno-stained by using the automated MCA system (Hitachi Chemical Co., Ltd). CTCs were defined as those positive for DAPI and cytokeratin (CK) and negative for CD45. PD-L1 expression level on CTCs was visualized by addition of PD-L1 immunocytochemistry procedure. High-resolution fluorescent images were obtained using fluorescence microscope (Carl Zeiss Microscopy Co., Ltd). Results: Characteristics of 20 lung cancer patients enrolled in clinical study were as follows: median age 74 (range, 48 to 84); male 60%; stage III/IV, 10/90%; NSCLC/SCLC, 70/30%. More than 2 CTCs were identified in 14 patients (median 22.5; range, 4 to 71), and PD-L1 positive CTCs were detected in 12 patients (median 5; range, 2 to 15). No correlation was detected between the number of total CTCs and that of PD-L1 positive CTCs in each patient (R2 = 0.05). We found a total of 25 CTC clusters from 20 patients, of which PD-L1 expression was both homogenous and heterogeneous. It is noteworthy that clustered CTCs have larger proportion of PD-L1 positive CTCs per whole clustered CTCs than that of non-clustered CTCs (24/54, 44% versus 51/347, 15%, respectively). We further focused on CTC-interacting white blood cells, which intensively bound with aggregated CTCs rather than single CTC (12/54, 22% versus 43/337, 13%, respectively). Our data implicate that PD-L1 expression on CTC correlates with aggregation of CTCs (p Conclusions: Our results showed that PD-L1 expression on CTCs was detectable and there is intrapatient heterogeneity of its expression in patients with advanced lung cancer. Further investigation is warranted to better understand the biological importance of the correlation between PD-1 expression and CTC aggregation and CTC bound to white blood cells. Citation Format: Woong Kim, Yasuhiro Koh, Hiroaki Akamatsu, Satomi Yagi, Ayaka Tanaka, Kuninobu Kanai, Atsushi Hayata, Ryota Shibaki, Masayuki Higuchi, Hisashige Kanbara, Takashi Kikuchi, Keiichiro Akamatsu, Masanori Nakanishi, Hiroki Ueda, Nobuyuki Yamamoto. Differential expression of PD-L1 on circulating tumor cells among patients with advanced lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2257.

Abstract 2244: Development of an automated device for size-based enrichment and isolation of circulating tumor cells in lung cancer patients

Background and Purpose: Circulating tumor cells (CTCs) are relatively rare cells defined as tumor cells circulating in the peripheral blood of patients with solid tumors. Diagnosis utilizing CTCs is expected to help guide decision-making for precision cancer medicine. We 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. Here we evaluated its performance using preclinical spike-in model and blood samples from non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) patients. Material and method: The automated MCA system consists of components such as chambered cartridge containing micro metal filter, reagent and waste reservoirs, and peristaltic pump. To evaluate the recovery of CTCs, preclinical experiments using NSCLC cells, NCI-H820, A549, NCI-H441 and NCI-H23 spiked into peripheral whole blood from healthy volunteers were performed. For clinical evaluation, 6 mL of peripheral whole blood was collected from 50 advanced lung cancer patients prior to the initiation of chemotherapy and from 10 healthy donors. Samples were collected in an EDTA-containing tube and were processed within 3 hours of blood draw. Recovered cells on the filter were then fixed, permeabilized, and stained automatically and high-resolution fluorescent images were obtained using fluorescence microscope. We defined CTC as DAPI-positive, cytokeratin-positive and CD45-negative cell. Results: Results of the preclinical study showed that up to 90% of spiked-in tumor cells were recovered, confirming that the detection sensitivity by this automated device is on par with that by previous manual detection procedure. Demographics of 50 lung cancer patients enrolled in clinical study were as follows: median age 72 (range, 48 to 85); male 66%; stage III/IV 12/88%; NSCLC/SCLC 78/22%. Cells defined as CTC were detected in 2 cases out of 10 healthy volunteers, of which CTC count was 1 and 2 / 6 mL, respectively. Three or more CTCs were detected in 71% of patients with advanced lung cancer (39 out of 50) and five or more CTCs were detected in 52% of patients (26 out of 50) (median CTC count 13.5). Among stage IV NSCLC patients, patients with extrathoracic metastasis tend to have more CTCs than in those with intrathoracic metasitasis (median CTC count, 8 versus 4, p = 0.058). A head-to-head comparison between CellSearch system and our system was conducted in NSCLC patients, showing the superiority of our system (median CTC count, 0 versus 11.25, p = 0.0001, n = 17). Conclusions Our results suggest that the automated MCA device has a clinical potential for CTCs diagnosis towards precision medicine in lung cancer. This device also enables higher throughput owing to its automated procedure. Further clinical evaluation including the detection of PD-L1 expression will be performed in an expansion cohort. Citation Format: Satomi Yagi, Yasuhiro Koh, Hiroaki Akamatsu, Woong Kim, Ayaka Tanaka, Kuninobu Kanai, Atsushi Hayata, Ryota Shibaki, Masayuki Higuchi, Hisashige Kanbara, Takashi Kikuchi, Keiichiro Akamatsu, Masanori Nakanishi, Hiroki Ueda, Nobuyuki Yamamoto. Development of an automated device for size-based enrichment and isolation of circulating tumor cells in lung cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2244.

Abstract B138: Evaluation of a novel automated device for size-based enrichment and isolation of CTCs in patients with advanced lung cancer

Circulating tumor cells (CTCs) are associated with prognosis of patients with advanced solid tumors including lung cancer and reflect characteristics of the respective primary tumor and its metastatic deposits. Assessment of CTCs is expected to improve effectiveness of anticancer therapy and to sophisticate our knowledge to cancer metastasis. We previously reported that detection of CTCs using microcavity array (MCA) system yielded the superior sensitivity than FDA-approved CellSearch system in patients with non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Here we developed the automated CTCs detection device and evaluated its performance using preclinical spike-in model and blood samples from NSCLC and SCLC patients. The feasibility study on the assessement of PD-L1 expression level was also performed. To evaluate the recovery of CTCs preclinically, NSCLC cells, H1975, A549, H441 and PC-14 were spiked into 6 mL of peripheral whole blood obtained from healthy volunteers. Then, cells were captured and immuno-stained by using automated MCA system. CTCs were defined as those positive for DAPI and cytokeratin (CK) and negative for CD45. Additionally, normal blood cells and cancer cells were distinguished according to their size. For clinical evaluation, 6 mL of peripheral whole blood was collected from 10 healthy donors and 30 advanced lung cancer patients prior to the initiation of chemotherapy. Head-to-head comparison with CellSearch system was also conducted. PD-L1 immunostaining was established in a preclinical spike-in study using NSCLC cell lines, H820, A549, H441, and H23 with varying PD-L1 expression levels and tested as an exploratory objective in a subset of patients enrolled in a clinical study. We confirmed that up to 90% of spiked-in tumor cells were recovered by the automated MCA system, suggesting that the detection sensitivity by this automated device is on par with that by previous detection procedure. Characteristics of 30 lung cancer patients in clinical study were as follows: median age 71 (range, 48 to 85); male 70%; stage III/IV 17/83%; NSCLC/SCLC 83/17%. Cells defined as CTC were detected in 2 cases out of 10 healthy volunteers, of which CTC count was 1 and 2 in 6 mL of peripheral blood, respectively. More than 2 CTCs were detected in 77% of patients with advanced lung cancer (n = 23/30) and more than 5 CTCs were detected in 50% of patients (n = 15/30) (median CTC count 5.5). Significantly more CTCs were detected by the automated MCA system than by CellSearch system. Among stage IV NSCLC patients, patients with extrathoracic metastasis tend to have more CTCs than in those without one (median CTC count, 8 versus 4, p = 0.058). No difference in CTC counts between NSCLC and SCLC was observed in this study cohort. PD-L1 expression was assessed in a subset of patients and intra-patient heterogeneity of PD-L1 staining among CTCs was observed in patients who harbor PD-L1-positive CTCs. Our results suggest that the automated MCA device for size-based enrichment and isolation of CTCs has a clinical potential for CTCs diagnosis towards precision medicine in lung cancer. This also enables us to deal with more samples owing to its automated procedure and higher throughput. Further clinical evaluation including PD-L1 expression will be performed in an expansion cohort and the biology of CTCs will be investigated utilizing this device. Citation Format: Woong Kim, Yasuhiro Koh, Hiroaki Akamatsu, Satomi Yagi, Ayaka Tanaka, Kuninobu Kanai, Atsushi Hayata, Ryota Shibaki, Masayuki Higuchi, Hisashige Kanbara, Takashi Kikuchi, Keiichiro Akamatsu, Masanori Nakanishi, Nobuyuki Yamamoto. Evaluation of a novel automated device for size-based enrichment and isolation of CTCs in patients with advanced lung cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B138.