Hisashige Kanbara

Size-Based Isolation of Circulating Tumor Cells in Lung Cancer Patients Using a Microcavity Array System

Background Epithelial cell adhesion molecule (EpCAM)-based enumeration of circulating tumor cells (CTC) has prognostic value in patients with solid tumors, such as advanced breast, colon, and prostate cancer. However, poor sensitivity has been reported for non-small cell lung cancer (NSCLC). To address this problem, we developed a microcavity array (MCA) system integrated with a miniaturized device for CTC isolation without relying on EpCAM expression. Here, we report the results of a clinical study on CTCs of advanced lung cancer patients in which we compared the MCA system with the CellSearch system, which employs the conventional EpCAM-based method. Methods Paired peripheral blood samples were collected from 43 metastatic lung cancer patients to enumerate CTCs using the CellSearch system according to the manufacturer’s protocol and the MCA system by immunolabeling and cytomorphological analysis. The presence of CTCs was assessed blindly and independently by both systems. Results CTCs were detected in 17 of 22 NSCLC patients using the MCA system versus 7 of 22 patients using the CellSearch system. On the other hand, CTCs were detected in 20 of 21 small cell lung cancer (SCLC) patients using the MCA system versus 12 of 21 patients using the CellSearch system. Significantly more CTCs in NSCLC patients were detected by the MCA system (median 13, range 0–291 cells/7.5 mL) than by the CellSearch system (median 0, range 0–37 cells/7.5 ml) demonstrating statistical superiority (p = 0.0015). Statistical significance was not reached in SCLC though the trend favoring the MCA system over the CellSearch system was observed (p = 0.2888). The MCA system also isolated CTC clusters from patients who had been identified as CTC negative using the CellSearch system. Conclusions The MCA system has a potential to isolate significantly more CTCs and CTC clusters in advanced lung cancer patients compared to the CellSearch system.

Microcavity array system for size-based enrichment of circulating tumor cells from the blood of patients with small-cell lung cancer

In this study, we present a method for efficient enrichment of small-sized circulating tumor cells (CTCs) such as those found in the blood of small-cell lung cancer (SCLC) patients using a microcavity array (MCA) system. To enrich CTCs from whole blood, a microfabricated nickel filter with a rectangular MCA (10(4) cavities/filter) was integrated with a miniaturized device, allowing for the isolation of tumor cells based on differences in size and deformability between tumor and blood cells. The shape and porosity of the MCA were optimized to efficiently capture small tumor cells on the microcavities under low flow resistance conditions, while allowing other blood cells to effectively pass through. Under optimized conditions, approximately 80% of SCLC (NCI-H69 and NCI-H82) cells spiked in 1 mL of whole blood were successfully recovered. In clinical samples, CTCs were detectable in 16 of 16 SCLC patients. In addition, the number of leukocytes captured on the rectangular MCA was significantly lower than that on the circular MCA (p < 0.001), suggesting that the use of the rectangular MCA diminishes a considerable number of carryover leukocytes. Therefore, our system has potential as a tool for the detection of CTCs in small cell-type tumors and detailed molecular analyses of CTCs.

Development of the automated circulating tumor cell recovery system with microcavity array

Circulating tumor cells (CTCs) are well recognized as useful biomarker for cancer diagnosis and potential target of drug discovery for metastatic cancer. Efficient and precise recovery of extremely low concentrations of CTCs from blood has been required to increase the detection sensitivity. Here, an automated system equipped with a microcavity array (MCA) was demonstrated for highly efficient and reproducible CTC recovery. The use of MCA allows selective recovery of cancer cells from whole blood on the basis of differences in size between tumor and blood cells. Intra- and inter-assays revealed that the automated system achieved high efficiency and reproducibility equal to the assay manually performed by well-trained operator. Under optimized assay workflow, the automated system allows efficient and precise cell recovery for non-small cell lung cancer cells spiked in whole blood. The automated CTC recovery system will contribute to high-throughput analysis in the further clinical studies on large cohort of cancer patients.

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.

Adhesion properties of electron-beam cured oligomers for pressure-sensitive-adhesives

Abstract The properties of non-solvent pressure-sensitive-adhesives of the cured oligomers were studied with relation to their structure. Two types of liquid oligomers having certain double bonds, namely the side-chain and telechelic types, were employed for the test. The telechelic pure oligomer was cured in lower concentration of double bonds than the side-chain oligomer. Peel strength of the oligomers was almost the same. In the addition of mercapto-functional chain transfer agent, however, the telechelic type resulted in remarkably better peel strength compared with the side-chain. Thus, it is suggested that, in the case of the telechelic oligomer, the polymerizing or crosslinking by ene-thiol addition occurs effectively, and the adhesives indicate rubberlike elasticity.

Abstract A056: Sequential tracking of PD-L1 expression on circulating tumor cells in NSCLC patients treated with nivolumab

Background: Nivolumab (anti-PD-1 antibody) has become a new standard treatment in pretreated, advanced non-small cell lung cancer (NSCLC). Although strong expression of PD-L1 on tumor tissue has predictive value, significance of its expression on circulating tumor cell (CTC) is unknown and its status can be changed during the treatment. Here, we conducted a serial evaluation of PD-1-expressing CTCs in NSCLC patients treated with nivolumab. Methods: Advanced NSCLC patients who receive nivolumab at Wakayama Medical University Hospital were enrolled in this prospective observational study (registered at UMIN (000024414)). Nivolumab was administered 3 mg/kg biweekly until progressive disease (PD) or unacceptable toxicity. Peripheral whole blood (3 mL) was collected in a EDTA collection tube (BD vacutainer) and processed within 3 hours for CTC evaluation at baseline, week 4, and week 8. CTCs were detected using microcavity array system (Hitachi Chemical Co.). PD-L1 expression was immunohistochemically examined on both tumor tissues and CTCs using anti-PD-L1 antibody, clone 28-8 (Abcam). Results: Thirty-eight patients were registered in this study between January 2016 and September 2016. Clinical characteristics of the patients were as follows: median age 68 (range, 49 to 86); male 73%; stage IV 100%; squamous/non-squamous, 30/65%. Regarding nivolumab treatment, overall response rate (ORR) was 22% (95% confidence interval (CI): 10-38%), and median progression-free survival (PFS) was 62 days (95%CI: 40-235 days). At baseline, CTCs were detected in all patients (median, 15; range, 1-90) and PD-L1-expressing CTCs were detected in 87% of patients. Tumor proportion score (TPS) of PD-L1 expression on CTCs varied from 6% to 100%. Matched tumor tissues were available from 14 patients and 7 showed the PD-L1 TPS ≥ 50%. PD-L1 status on CTCs was not correlated with that on tumor tissues both using proportional score and H score (Spearman’s correlation: r = 0.0007 and 0.08, respectively). On CTCs, patients with PD-L1 ≥ 50 have significantly higher disease control rate than those with below 50% (83.3% versus 36.4%, p Citation Format: Hiroaki Akamatsu, Yasuhiro Koh, Keita Mori, Kuninobu Kanai, Atsushi Hayata, Nahomi Tokudome, Masayuki Higuchi, HIsashige Kanbara, Keiichiro Akamatsu, Masanori Nakanishi, Hiroki Ueda, Nobuyuki Yamamoto. Sequential tracking of PD-L1 expression on circulating tumor cells in NSCLC patients treated with nivolumab [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A056.

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.

Abstract 1458: Efficient isolation of circulating tumor cells in small cell lung cancer patients using size- and geometry-controlled microcavity array system.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background: We have developed a microcavity array (MCA) system integrated with a miniaturized device for the isolation of circulating tumor cells (CTC) without relying on EpCAM expression. The MCA system allows the filtration of tumor cells from whole blood on the basis of differences in the size between tumor and blood cells. The previous study has shown that the MCA system is potentially superior to the conventional epithelial antigen-based method for detecting CTCs in non-small cell lung cancer. Recently, we further optimized the shape and porosity of MCA to efficiently isolate smaller tumor cells as in small cell lung cancer (SCLC). Here we report the results of clinical study in SCLC patients comparing MCA system to CellSearch system and exploratory study of novel rectangular-shaped MCA system. Methods: The MCA is made of nickel by electroforming and circular MCA is fabricated with 8-9 μm diameter pores. Meanwhile, novel rectangular-shaped MCA is fabricated with 5-9 μm-wide and 30-60 μm-long pores. NCI-H69 (12 μm in diameter) SCLC cells were used for spike-in experiments. CTCs were defined as cells with round to oval morphology, a visible nucleus, positive for cytokeratin and negative for CD45. For the clinical evaluation, paired peripheral blood samples were collected from 18 SCLC patients to compare the performance of the CellSearch system and the MCA system for CTC detection. Results: The recovery rate of spiked NCI-H69 cells with the rectangular-shaped MCA (80 ± 2%) was significantly higher than that with the circular MCA (67 ± 4%) (p=0.01, t-test). In addition, the carryover of leukocytes on the rectangular-shaped MCA was 7-fold lower than that on the circular MCA in the experiment using healthy donor blood. The fluctuation of flow resistance during filtration with the rectangular-shaped MCA (<1.5 kPa) was smaller than that with the circular MCA (2 kPa); the rectangular-shaped MCA enabled recovery of small tumor cells with high efficiency. In clinical study, compared to the CellSearch, the circular and rectangular-shaped MCA system identified significantly more SCLC patients (9 of 18 vs. 18 of 18 vs. 17 of 18, respectively) as CTC positive. No significant difference was observed in the CTC counts between the rectangular-shaped MCA (median 16, range 0-545 cells/7.5 mL) and the circular MCA (median 23, range 2-2329 cells/7.5 mL) (p=0.77, Wilcoxon test). In contrast, the number of captured leukocytes on the rectangular-shaped MCA was significantly lower than that on the circular MCA (p<0.0001, Wilcoxon test), suggesting that implementing the rectangular-shaped MCA diminishes a considerable number of carryover leukocytes. Conclusion: The MCA system has a potential as a tool for the efficient recovery of CTCs in small cell type tumors with high purity, while offering the additional advantages in cost, portability, and capacity to perform more detailed analyses of CTCs. Citation Format: Masahito Hosokawa, Hirotsugu Kenmotsu, Yasuhiro Koh, Tomoko Yoshino, Tsuyoshi Tanaka, Tateaki Naito, Toshiaki Takahashi, Haruyasu Murakami, Yukiko Nakamura, Asuka Tsuya, Takehito Shukuya, Akira Ono, Hiroaki Akamatsu, Reiko Watanabe, Sachiyo Ono, Hisashige Kanbara, Tadashi Matsunaga, Nobuyuki Yamamoto. Efficient isolation of circulating tumor cells in small cell lung cancer patients using size- and geometry-controlled microcavity array system. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1458. doi:10.1158/1538-7445.AM2013-1458