Abstract P6-01-29: Serial genomic analysis of circulating free DNA and change of immune-related gene signature in triple negative and HER2 positive advanced, metastatic breast cancer

Background: Circulating tumor cells (CTCs) and circulating free DNA (cfDNA) have a promising role for detecting early response and progression in breast cancer. Furthermore, change of immune-related gene signature during systemic treatment influence the treatment response of breast cancer. Herein we report the outcome of serial genomic analysis of CTC, cfDNA and change of immune-related gene signature in advanced, metastatic triple negative breast cancer (TNBC) and HER2 positive breast cancer (BC). Methods: Serial whole blood were prospectively collected in 18 early or advanced, and 10 metastatic BC patients periodically during systemic chemotherapy. CTC was isolated from whole blood through EpCAM positive bead selection, and ctDNA was isolated from plasma. For genomic profiling of CTC and ctDNA, Oncomine™ Comprehensive Assay Plus and Oncomine™ Pan-Cancer cfDNA assay (included BRCA1, BRCA2 and MYCN customized panel) was performed and analyzed, respectively. Total RNA was extracted using whole blood and analyzed using Nanostring Pancancer Immunology Panel. Results: Total 61 serial samples were obtained from 28 patients during the study. At baseline, FGFR4 mutation was the most commonly detected (10 patients, 76.9%) with median variant of allele frequency (VAF) of 54.5% (range 20.87~99.8%) in advanced and metastatic TNBC based on CTC analysis. In case of cfDNA, 11 patients (84.6%) showed TP53 mutation with low VAF (median 1.8%, range 0.1~12.3%). In HER2 positive BC, FGFR4 was also the most common mutation (5 patients [62.5%]; median VAF 57.9%) in CTC analysis and TP53 was most frequently detected (5 patients, [62.5%]; median VAF 3.0%) in cfDNA analysis. In three pathogenic gBRCA1 mutated patients, BRCA1 was identically detected in 2 patients based on CTC analysis and in 3 patients based on cfDNA analysis with VAF of approximately 50%. There were no significant changes of VAF in target mutations of CTC and cfDNA during systemic treatment, irrespective of tumor response and subtype. However, in one patients who harbored 13 mutations detected based on baseline CTC analysis, showed disappearance of 12 mutations in final CTC analysis with partial response based on radiologic findings. In contrary, there was another patient who gained multiple mutations during CTC analysis during neoadjuvant chemotherapy (NAC) with gain of tumor mutational burden (TMB). She did not achieve pathologic complete response and RCB score was 3 after completion of NAC. Most TNBC patients who received NAC and showed partial response, TMB showed gradual decrease during treatment. Baseline immune-related gene signatures were compared between HER2(+) BC and TNBC, and type 1 interferon signaling pathway was upregulated in HER2 (+) BC compared to TNBC. Conclusions: Our study suggest that serial follow up CTC and ctDNA, immune-related gene signature is feasible and reflect the general characteristics of baseline characteristics and dynamic molecular alteration of breast cancer. Further analysis with larger patient sample and correlation with tumor tissue is warranted in the future.

Citation Format: Jieun Lee, Kabsoo Shin, Seung Yeon Joe, Hayoon Lee, Byung Hee Jeon, Ahwon Lee. Serial genomic analysis of circulating free DNA and change of immune-related gene signature in triple negative and HER2 positive advanced, metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-29.

Serial genomic analysis of circulating tumor cells and circulating tumor DNA in triple-negative and HER2-positive advanced, metastatic breast cancer

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Background: Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have a promising role for detecting early response and progression in breast cancer. We performed serial genomic analysis of CTC and ctDNA in advanced, metastatic triple negative breast cancer (TNBC) and HER2 positive breast cancer (BC). Methods: Serial CTCs, ctDNA were prospectively collected in 9 early or advanced, and 10 metastatic BC patients periodically during systemic chemotherapy. CTC was isolated from whole blood through EpCAM positive bead selection, and ctDNA was isolated from plasma. For genomic profiling of CTC and ctDNA, Oncomine™ Comprehensive Assay Plus and Oncomine™ Pan-Cancer cfDNA assay (included BRCA1, BRCA2 and MYCN customized panel) was performed and analyzed, respectively. Results: TP63 was most commonly detected mutation (13 patients, 68.4%) at serial CTC analysis with median variant of allele frequency (VAF) of 18.6% (range 11.5̃25.2%), irrespective of tumor subtype and stage. In ctDNA analysis, 11 patients showed TP53 mutation with low VAF (median 1.4%, range 0.3̃12.3%). FGFR4 was equally detected, with median variant of allele frequency (VAF) of 57.2% (range 46.6-99.8) and there was no change of FGFR4 VAF irrespective of tumor response in CTC analysis. In three gBRCA1 mutated patients, BRCA1 was identically detected in 3 patients based on CTC analysis and in 2 patients based on ctDNA analysis with VAF of approximately 50%. There were no significant changes of VAF in target mutations of CTC irrespective of tumor response and subtype. In TNBC patients who received neoadjuvant chemotherapy, tumor mutation burden (TMB) showed gradual decrease during treatment. However, there were initial surge of TMB in HER2 positive BC patients who received neoadjuvant chemotherapy, irrespective of presence of pathologic complete response. Conclusions: Our study suggest that serial follow up CTC and ctDNA is feasible and reflect the general characteristics of baseline characteristics and dynamic molecular alteration of breast cancer. Further analysis with larger patient sample and correlation with tumor tissue is warranted in the future.

Abstract 663: Longitudinal AXL assessment of circulating tumor cells (CTCs) and its clinical implication in the patients with EGFR mutated non-small cell lung cancer (NSCLC)

Gefitinib for EGFR mutated non-small cell lung cancer (NSCLC) is showing acquired resistance after 8-11 months, and about 60% of its mechanisms have been reported due to T790M mutation. In about a third of NSCLC, AXL expression can be observed at baseline status. And because AXL expression could be a mechanism of drug resistance, we decided to monitor AXL expression before and after Gefitinib treatment in EGFR mutated NSCLC patients through circulating tumor cells (CTCs). Herein, Thirty-seven out of 55 participants who showed acquired resistance to EGFR-TKI were selected in this prospective analysis. To evaluate the AXL expression on the CTCs, serial blood was obtained (tracking for 4, 12, 24 and 36 weeks after EGFR-TKIs). Baseline tumor tissues were also obtained for genetic analysis. Progression-free survival (PFS) and overall survival (OS) were explored according to the baseline AXL expression. AXL expression was analyzed by observation and quantitative intensity-dependent fold change analysis using immunofluorescence analysis. CTCs were isolated and analyzed by CytoGen's Smart Liquid Biopsy platform that uses the size-based gravity filtration for CTC isolation. We found out that there were ten cases (27%) of the increasing pattern of AXL expression in CTCs during longitudinal monitoring in patients with progressive disease (PD). The most remarkable aspect is that AXL up-regulation in CTCs preceded the time point of clinical PD. These results imply that the expectation of clinical PD by blood CTC (liquid biopsy-based examination) can be combined with the T790M. Moreover, the PFS (p= 0.002) and OS (p= 0.007) were both worse in patients with AXL expression at the baseline status compared with patients without AXL expression (N=55). Conclusively, this study implicates that AXL in CTCs could be deployed for prognostic evaluation. And the clinical monitoring of specific target marker in CTC could help for further treatment strategy.

Citation Format: Mi Young Choi, Da Hye Moon, Hae Ung Lee, Jong Min Jo, Young Woong Sohn, Byung Hee Jeon, Sang-We Kim. Longitudinal AXL assessment of circulating tumor cells (CTCs) and its clinical implication in the patients with EGFR mutated non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 663.

Circulating tumor cell proportion scoring (CTPS) based PD-L1 assessment and clinical application of circulating tumor cells (CTCs) on stage IV non-small cell lung cancer (NSCLC) through liquid biopsy

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Background: Stage IV lung cancer is the most advanced lung cancer state accompanied by metastasized to the area around the lungs or distant major organs. The most common type of lung cancer is non-small cell lung cancer, which is more aggressive and may spread quickly due to organ-specific complex networks such as lymph and major blood vessels. Thus, only precise diagnostic strategy approaches will determine the effectiveness of the actual and successful clinical treatment. Until a recent date, Immunohistochemistry (IHC) for programmed death-ligand 1(PD-L1) test is the only available biomarker test that purpose diagnostics (CDx) and guide the treatment with immune checkpoint inhibitors in NSCLC. Methods: Given that CDx strategy, tissue biopsy has inevitable limitations, including patient risk, repetitive examination, sample preparation, sensitivity, and accuracy. For this reason, our research team contrived the best strategy for biomarker, PD-L1-specific CTCs in stage IV NSCLC group (N = 30) compared to pulmonary inflammatory patient groups (N = 30) CytoGen Smart biopsy platform. Herein, we removed false-positive cells for the first strategy of distinguishing between lymphoid/myeloid cells and the enriched-CTCs. And the second strategic approach is to calculate the pure CTCs (without false-positive cells) and then CTPS) as measured by the PD-L1 expression among pure-CTCs. That application is the percentage of viable CTCs showing partial or complete stained cells at the deducted cut-off value in each fluorescence, respectively. Results: Consequently, we demonstrated over 80% of the concordance rate between VENTANA PD-L1(SP263) and DAKO PD-L1(SP263) assay tested by the PD-L1 expression on stage IV NSCLC in tissue and pure-CTCs based CTPS from the blood. In contrast, pure-CTCs based CTPS in the pulmonary inflammatory group were all negative (recorded as zero). Conclusions: Conclusively, this study implicates that pure-CTCs based CTPS could be deployed for innovative diagnosis strategies as alternatives for tissue biopsy. Our clinical study's data suggested that the possibility for prompt decision for diagnosis and gain powerful insights to guide the personalized treatment in NSCLCs. Clinical trial information: 2020-0553.

Clinical Utility of Combined Circulating Tumor Cell and Circulating Tumor DNA Assays for Diagnosis of Primary Lung Cancer

BACKGROUND/AIM

Although it has been suggested that circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) might be used in a complementary manner in lung cancer diagnosis, limited confirmatory data are available. In this prospective study, we evaluated the diagnostic performance of each assay separately and in combination.

PATIENTS AND METHODS

From March 2018 to January 2019, patients with suspected primary lung cancer, who underwent routine lung cancer work-up and peripheral blood sampling, were prospectively enrolled in the study. Epithelial cell adhesion molecule and cytokeratin served as markers of CTCs. In terms of ctDNA analysis, single-nucleotide variants were evaluated via next-generation sequencing.

RESULTS

We analyzed 111 patients, including 99 with primary lung cancer and 12 with benign pulmonary disease. The median number of CTCs in 10 ml of blood was 3. The most frequently detected single nucleotide variants of ctDNA were TP53, CDKN2A, and EGFR. The diagnostic sensitivity of conventional tumor marker (combination of carcinoembryonic antigen/CYFRA 21-1/neuron-specific enolase) was 66.7%, while those of the ctDNA and CTC assays were 72.7% and 65.7%, respectively. The sensitivity of the CTC/ctDNA combination (95.0%) was significantly greater than those of the CTC (p<0.001), ctDNA (p<0.001), or conventional tumor marker (p<0.001) alone. Subgroup analysis revealed that the sensitivity of the combination assay was greater than those of the CTC or ctDNA assays alone, regardless of tumor stage or histopathology type.

CONCLUSION

The CTC/ctDNA combination assay enhanced the sensitivity of primary lung cancer diagnosis. The combination assay strategy may be clinically useful and could enhance the early detection of lung cancer (ClinicalTrials.gov number: NCT03479099).

Prediction and prognostic validation of colorectal cancer therapeutic effect of WM-S1-030 using pre-clinical CTC animal model

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Background: CTC (Circulating tumor cells) has the advantage of being able to effectively investigate non-invasive diagnosis, prediction, and prognosis for non-surgical carcinoma or tissue sample collection. We have developed WM-S1-030 (WMBIO) as a novel inhibitor for mtRTK (mutant receptor tyrosine kinase) identified important targets for cancer progression and metastasis in various cancers, including colorectal cancer, and have tried to prove the possibility of CTC diagnosis, prediction and prognosis of WM-S1-030 using tumor animal models. Methods: Six of colon cancer cell lines expressing mtRTK (pTyr-mtRTK) were transplanted into Balb.c nude mice and NSG mice to collect peripheral blood when the tumor size reached 1000 mm3. CTCs were quantified in peripheral blood using the Smart Biopsy cell isolator (Cytogen). The expression of pTyr-mtRTK in CTCs was analyzed via the Smart Biopsy Image Analyzer (Cytogen). Colon cancer cell lines expressing pTyr-mtRTK were transplanted into NSG mice and we examined the tumor suppression, the enumeration of CTCs and pTyr-mtRTK expression in CTCs after administration of WM-S1-030. We also identified CTCs in peripheral blood of colon cancer patients and analyzed expression of pTyr-mtRTK in CTCs through Smart Biopsy system. Results: As results of the enumeration of CTCs after tumor transplantation into Balb.c nude mice and NSG mice, the number of CTC was 8 ~ 20 times higher peripheral blood in the NSG model, which indicates innate immune responses are critical for the survival of CTCs. Half of CTCs isolated from the blood expressed pTyr-mtRTK. The tumor size, the number of CTCs, and the expression of pTyr-mtRTK in CTCs were examined after the administration of WM-S1-030. The volume of tumor decreased by 67% in the WM-S1-030 group compared to the vehicle. The number of CTCs was reduced by approximately three times after the treatment of WM-S1-030 and also the number of CTCs expressing pTyr-mtRTK was significantly decreased. CTC detection and pTyr-mtRTK expression analysis in the peripheral blood of colon cancer patients detected 9 CTCs per 10 ml of peripheral blood, of which 11 % of CTCs representing pTyr-mtRTK were confirmed. Conclusions: WM-S1-030 was developed and confirmed in the CTC-based animal model, which implies that the analysis of CTCs is the powerful tool for predicting/ prognosing WM-S1-030 in the pre-clinical analysis. Currently, we are conducting clinical diagnostic validation using CTC in the blood of colorectal cancer patients and preparing for clinical trial of WM-S1-030.

Circulating Tumor Cell Counts in Patients With Localized Prostate Cancer Including Those Under Active Surveillance

AIM

To evaluate the clinical efficacy of a circulating tumor cell (CTC) test by comparison between healthy volunteers and patients with localized prostate cancer including those under active surveillance.

MATERIALS AND METHODS

CTC counts in peripheral blood were compared between patients with prostate cancer (n=45) and healthy volunteers (n=17). CTCs were identified based on the expression of epithelial cell adhesion molecule (EpCAM) and counted using a SMART BIOPSY™ SYSTEM.

RESULTS

The number of EpCAM+ cells was significantly higher in patients with cancer than in healthy volunteers. Among the low-risk patients (n=9), two had up-staging and six had up-grading. Among those up-staged, there was one case which was EpCAM⁺ Among those cases up-graded, three were EpCAM⁺ In those with stage T2 tumors, the presence of Gleason pattern 5 was positively correlated with EpCAM positivity (rho=0.59, p<0.001).

CONCLUSION

CTC counts in localized prostate cancer were associated with Gleason pattern 5. Active treatment should be considered for patients with low-risk disease during active surveillance who are found to have EpCAM+ CTCs because of a risk of up-staging and up-grading.

Cancer panel analysis of circulating tumor cells in patients with breast cancer

Liquid biopsy using circulating tumor cells (CTCs) is a noninvasive and repeatable procedure, and is therefore useful for molecular assays. However, the rarity of CTCs remains a challenge. To overcome this issue, our group developed a novel technology for the isolation of CTCs on the basis of cell size difference. The present study isolated CTCs from patients with breast cancer using this method, and then used these cells for cancer gene panel analysis. Blood samples from eight patients with breast cancer were collected, and CTCs were enriched using size-based filtration. Enriched CTCs were counted using immunofluorescent staining with an epithelial cell adhesion molecule (EpCAM) and CD45 antibodies. CTC genomic DNA was extracted, amplified, and screened for mutations in 400 genes using the Ion AmpliSeq Comprehensive Cancer Panel. White blood cells (WBCs) from the same patient served as a negative control, and mutations in CTCs and WBCs were compared. EpCAM⁺ cells were detected in seven out of eight patients, and the average number of EpCAM⁺ cells was 8.6. The average amount of amplified DNA was 32.7 µg, and the percentage of reads mapped to any targeted region relative to all reads mapped to the reference was 98.6%. The detection rate of CTC-specific mutations was 62.5%. The CTC-specific mutations were enhancer of zeste polycomb repressive complex 2 subunit, notch 1, AT-rich interaction domain 1A, serine/threonine kinase 11, fms related tyrosine kinase 3, MYCN proto-oncogene, bHLH transcription factor, APC, WNT signaling pathway regulator, and phosphatase and tensin homolog. The technique used by the present study was demonstrated to be effective at isolating CTCs at a sufficiently high purity for genomic analysis, and supported the use of comprehensive cancer panel analysis as a potential application for precision medicine.

Identification of circulating tumor cells with EML4-ALK translocation using fluorescence in situ hybridization in advanced ALK-positive patients with lung cancer

Analysis of anaplastic lymphoma kinase (ALK) rearrangement in non-small cell lung cancer (NSCLC) is considered to be a useful tool when considering predictive biomarker detection for evaluating eligibility for targeted therapy. It is not always possible to perform a tumor biopsy in patients. Isolation and culturing of circulating tumor cells (CTCs) may be an alternative to tumor biopsies for the diagnosis of ALK rearrangement. Blood was collected from 22 patients with NSCLC harboring ALK rearrangement and was divided into two groups: One for immunofluorescence staining and the other for culture. Samples were filtered by size and cultured CTCs were analyzed for echinoderm microtubule-associated protein-like 4-ALK translocation using fluorescence in situ hybridization. CTCs positive for epithelial cell adhesion molecule and CTCs exhibiting ALK rearrangement were detected. Therefore, CTCs may be used as a potential alternative method to tissue biopsy for diagnosing ALK rearrangement. Additionally, this method may have clinical applications including serial blood sampling for the development of personalized cancer therapy based on individual genomic information.

Abstract 1737: ALK rearrangement analysis in circulating tumor cells of lung cancer patients

The evaluation of ALK rearrangement in non-small-cell lung cancer (NSCLC) is a significant tool when considering chemotherapy. It is not always possible to perform a tumor biopsy in patients. We suggest isolation and culturing of circulating tumor cells (CTCs) as an alternative tool to a tumor biopsy for the diagnosis of ALK rearrangement. From 22 patients with NSCLC harboring ALK rearrangement, blood samples were collected and divided into two parts: one for immunofluorescence staining of CTC marker and the other for culturing of CTCs. Both samples were processed by size-based filtration, and Cultured CTCs were analyzed for EML4-ALK translocation by fluorescence in situ hybridization (FISH) using Vysis ALK break apart FISH probe kit. CTC culturing was successful in 18 of 22 cases (81.8%). Among 18 cases of successful CTC cultures, 13 cases showed ALK rearrangement positivity (72.2%). Therefore, we suggest that the CTCs can be used as an alternative method to tissue biopsy for diagnosing ALK rearrangement. In addition, this method may have clinical applications including serial blood sampling for the development of personalized cancer therapy based on individual genomic information.

Citation Format: Min Kyung Jeon, Young Hun Kim, Eunjoo Hwang, Hye Seon Lee, Ji-hyun Uh, Myoung Shin Kim, JooKyung Park, Byung Hee Jeon, Se-Hoon Lee. ALK rearrangement analysis in circulating tumor cells of lung cancer patients [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 1737. doi:10.1158/1538-7445.AM2017-1737

Cancer gene panel analysis of cultured circulating tumor cells and primary tumor tissue from patients with breast cancer

Although numerous effective therapies have improved the survival rate of patients with breast cancer, a number of patients present with tumor recurrence and metastasis. A liquid biopsy of circulating tumor cells (CTC) is a non-invasive method to obtain tumor cells and may be used as substitute for a tumor tissue biopsy. The present study focuses on determining whether CTC culture is an optimal method of obtaining sufficient amounts of CTCs for molecular analysis. The current study demonstrates a method of isolating and culturing CTCs from patients with breast cancer and the construction of a molecular profile of cultured cells using the Ion AmpliSeq Cancer Gene Panel V2. Gene mutations that were observed in cultured CTCs were compared with those observed in primary tumor tissues. CTCs were isolated and cultured from the blood of six patients with breast cancer. Mutations from the Catalogue Of Somatic Mutation In Cancer (COSMIC) were detected in Platelet-Derived Growth Factor Receptor Alpha, MET (also known as Hepatocyte Growth Factor Receptor), Phosphatase and Tensin Homolog, Harvey Rat Sarcoma Viral Oncogene Homolog, SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin Subfamily B Member 1, Cyclin Dependent Kinase Inhibitor 2A and MutL Homolog 1 genes in 5/6 samples. A comparison between mutations detected in cultured CTCs and mutations detected in primary tumor tissues demonstrated that a large number of mutations that were identified in CTCs were also detected in primary tumor tissues. The results from the current study describe a novel cell culture approach that may be used to obtain an optimal number of CTCs for molecular analysis. This novel approach is able to be used as a tool for liquid biopsy during breast cancer treatment.

Evaluation of a novel approach to circulating tumor cell isolation for cancer gene panel analysis in patients with breast cancer

Liquid biopsy isolation of circulating tumor cells (CTCs) allows the genomic analysis of CTCs, which is useful in the determination of personalized cancer therapy. In the present study, CTCs from patients with breast cancer were enriched and successfully analyzed using cancer gene panel analysis. Blood samples from 11 patients with breast cancer were collected and CTCs enriched for using size-based filtration. The enriched CTCs were analyzed using immunofluorescence staining with antibodies directed against epithelial cell adhesion molecule (EpCAM) and cluster of differentiation 45. The genomic DNA of CTCs was extracted, amplified and 50 genes screened for mutations using the Ion AmpliSeq™ Cancer Hotspot Panel v2. EpCAM staining detected CTCs in 10/11 patients and the average CTC count was 3.9 in 5 ml blood. The average purity of enriched CTCs was 14.2±29.4% and the average amount of amplified DNA was 28.6±11.9 µg. Catalogue Of Somatic Mutations In Cancer mutations were detected in the CTCs and included IDH2, TP53, NRAS, IDH1, PDGFRA, HRAS, STK11, EGFR, PTEN, MLH1, PIK3CA, CDKN2A, KIT and SMARCB1. In conclusion, a novel size-based filtration approach for the isolation of CTCs was evaluated and successfully applied for the genomic analysis of CTCs from patients with breast cancer.

Complete plastid genome of an ecologically important brown alga Sargassum thunbergii (Fucales, Phaeophyceae)

The brown algal species Sargassum thunbergii (Fucales, Phaeophyceae) is widely distributed in coastal area of East Asia. This alga is ecologically and economically important seaweeds; however, no genome data was reported thus far. To get a better understanding of organellar genome of S. thunbergii, we sequenced and annotated its complete plastid genome. The circular plastid genome is 124,592bp in size with 30.4% GC content, which is composed of a large single-copy (LSC) region of 73,668bp, a small single-copy (SSC) region of 40,032bp, and two inverted repeat (IR) of 5446bp each. The plastid genome of S. thunbergii includes 139 protein-coding genes, six ribosomal RNA (rRNA) operons, 28 transfer RNA (tRNA) sequences, and one intron (214bp) in tRNA-Leu (trnL) gene. Five overlapping genes were identified in the compact plastid genome. Base on the comparison with previously published five brown algae plastid genomes, we found that the gene content and gene order of S. thunbergii are identical to that of other Fucales species Fucus vesiculosus.

Microscopic mechanism underlying double-state lasing in an InAs/GaAs quantum dot laser diode elucidated using coupled rate equations and the spontaneous emission recorded from a window structure

We investigated the microscopic mechanism underlying the double-state lasing behavior (simultaneous lasing at the ground state [GS] and excited state [ES]) in InAs/GaAs quantum dot (QD) laser diodes. The ES and GS lasing processes that contributed to double-state lasing were examined experimentally and theoretically. Experiments were conducted in which spontaneous emission from a window of a QD laser diode was examined under lasing conditions, and numerical simulations were performed using a coupled rate equation model of the QD microstates. The findings showed that, when carrier relaxation from the ES to the GS was sufficiently slow, double-state lasing occurred. Additionally, ES lasing was found to arise not from the QD group undergoing GS lasing, but rather from another QD group in which the states were lower in energy and outside of the homogeneous bandwidth.

Abstract 391: Utility of circulating tumor cell (CTC) in advanced gastric cancer

Circulating tumor cells (CTCs), known as the “leukemic phase” of solid tumor, have been associated with poor prognosis and clinical outcome in various cancer including breast and colorectal. However, fewer studies reported characteristic and usefulness of CTC as an indicator in gastric cancer (GC). In this study, we evaluated utility of CTC in advanced GC cancer. First, we confirmed detection rate of GC cancer cell lines as a spiking test, and then defined CTC as DAPI+, EpCAM+ and CD45- cells through immunofluorescence stating. To determine a cut-off for CTC of GC, we assessed the number of CTCs in blood of 22 healthy volunteers, and observed 1 (3/22) to 2 (1/22) of CTCs. Based on these results, we determined CTC positivity of GC as more than 3 CTCs. When we evaluated CTC positive rate in Stage IV GC patients, 28 patients were

CTC positive (30.1%) with the median number of CTC 5 (range 3 to over 100). Interestingly, 3 out of 28 patients were showed more than 100 CTCs. While, in operable GC patients (Stage I to III), CTC positivity was 18.4% (7/38) and median number of CTC was 4 (range 3 to 9) in CTC positive patients. These results showed that Stage IV GC patients have high number of CTCs than operable GC patients. Tumor histology and Lauren classification did not affect to CTC positivity in Stage IV and operable GC patients. We also observed the potential use of CTC in serial follow-ups and one of the cases shows the decreasing CTCs followed by clinical response. In conclusion, this study demonstrates that detection of CTC may be useful prognostic indicator of GC cancer patients.

Citation Format: Won Suk Lee, Jeong Min Kim, Woo Sun Kwon, So Jung Lim, Tae Soo Kim, Ga Yun Kim, Sung Ho Choi, Byung Hee Jeon, Min Kyu Jung, Joong Bae Ahn, Hyun Cheol Chung, Sun Young Rha. Utility of circulating tumor cell (CTC) in advanced gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 391. doi:10.1158/1538-7445.AM2015-391

Attenuated benzodiazepine-sensitive tonic GABAA currents of supraoptic magnocellular neuroendocrine cells in 24-h water-deprived rats

In supraoptic nucleus (SON) magnocellular neurosecretory cells (MNCs), γ-GABA, via activation of GABAA receptors (GABAA Rs), mediates persistent tonic inhibitory currents (Itonic ), as well as conventional inhibitory postsynaptic currents (IPSCs, Iphasic ). In the present study, we examined the functional significance of Itonic in SON MNCs challenged by 24-h water deprivation (24WD). Although the main characteristics of spontaneous IPSCs were similar in 24WD compared to euhydrated (EU) rats, Itonic , measured by bicuculline (BIC)-induced Iholding shifts, was significantly smaller in 24WD compared to EU rats (P < 0.05). Propofol and diazepam prolonged IPSC decay time to a similar extent in both groups but induced less Itonic in 24WD compared to EU rats, suggesting a selective decrease in GABAA receptors mediating Itonic over Iphasic in 24WD rats. THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol), a preferential δ subunit agonist, and L-655,708, a GABAA receptor α5 subunit selective imidazobenzodiazepine, caused a significantly smaller inward and outward shift in Iholding , respectively, in 24WD compared to EU rats (P < 0.05 in both cases), suggesting an overall decrease in the α5 subunit-containing GABAA Rs and the δ subunit-containing receptors mediating Itonic in 24WD animals. Consistent with a decrease in 24WD Itonic , bath application of GABA induced significantly less inhibition of the neuronal firing activity in 24WD compared to EU SON MNCs (P < 0.05). Taken together, the results of the present study indicate a selective decrease in GABAA Rs functions mediating Itonic as opposed to those mediating Iphasic in SON MNCs, demonstrating the functional significance of Itonic with respect to increasing neuronal excitability and hormone secretion in 24WD rats.

Inhibition of human cytochrome P450 isoforms and NADPH-CYP reductase in vitro by 15 herbal medicines, including Epimedii herba

OBJECTIVE

We evaluated the potential of 15 herbal medicines (HMs), commonly used in Korea, to inhibit the catalytic activities of several cytochrome P450 (CYP) isoforms and microsomal NADPH-CYP reductase.

METHODS

The abilities of 1-1000 microg/mL of freeze-dried aqueous extracts of 15 HMs to inhibit phenacetin O-deethylation (CYP1A2), tolbutamide 4-methylhydroxylation (CYP2C9), S-mephenytoin 4'-hydroxylation (CYP2C19), dextromethorphan O-demethylation (CYP2D6), chlorzoxazone 6-hydroxylation (CYP2E1), midazolam 1-hydroxylation (CYP3A4) and NADPH-CYP reductase were tested using human liver microsomes.

RESULTS

The HMs Epimedii herba, Glycyrrhizae radix and Leonuri herba inhibited one or more of the CYP isoforms or NADPH-CYP reductase. Of the three HMs, Epimedii herba extracts were the most potent inhibitors of several CYP isoforms (IC(50) 67.5 microg/mL for CYP2C19, 104.8 microg/mL for CYP2E1, 110.9 microg/mL for CYP2C9, 121.9 microg/mL for CYP3A4, 157.8 microg/mL for CYP2D6 and 168.7 microg/mL for CYP1A2) and NADPH-CYP reductase (IC(50) 185.9 microg/mL ).

CONCLUSION

These results suggest that some of the HMs used in Korea have the potential to inhibit CYP isoforms in vitro. Although the plasma concentrations of the active constituents of the HMs were not determined, some herbs could cause clinically significant interactions because the usual doses of those individual herbs are several grams of freeze-dried extracts. Controlled trials to test the significance of these results are necessary.

A gadolinium and pH-sensitive hyperpolarization-activated cation current in acutely isolated single neurones from Fasciola hepatica

Fasciola hepatica, a parasitic flatworm belonging to the Class Trematoda, is one of the first metazoan groups to possess a centralized nervous system. However, the electrophysiological properties of neurones in F. hepatica are largely unknown. In the present study, we acutely isolated viable neurones from F. hepatica and characterized their electrophysiological properties. A hyperpolarization-activated cation current was recorded in the cells using the whole-cell patch-clamp. The current was found to be activated slowly at membrane potentials negative to 0 mV and did not display any time-dependent inactivation. This current was reduced by 1 mM Gd3+ to the level of the leak current, while 3 mM of Cs+ had no effect. However, the current was inhibited by extracellular acidosis in the pH range 7.0-7.8, and the membrane potentials of these cells were depolarized by extracellular alkalosis in the pH range of 5.8 to 8.2. Gd3+ (1 mM), which inhibited the pH-sensitive hyperpolarization-activated cation current, also hyperpolarized the cells. In summary, we isolated single neurones from F. hepatica, and these were found to express a pH-sensitive hyperpolarization-activated cation current. This current may participate in the membrane depolarization of F. hepatica neurones during alkaline challenge.

Redox factor-1: an extra-nuclear role in the regulation of endothelial oxidative stress and apoptosis

The rac1 GTPase promotes oxidative stress through reactive oxygen species (ROS) production, whereas the DNA repair enzyme and transcriptional regulator redox factor-1 (ref-1) protects against cell death due to oxidative stimuli. However, the function of ref-1 in regulating intracellular oxidative stress, particularly that induced by rac1, has not been defined. We examined the role of ref-1 in vascular endothelial cell oxidative stress and apoptosis. Ref-1 was expressed in both the cytoplasm and nuclei of resting endothelial cells. Cytoplasmic ref-1 translocated to the nucleus with the oxidative trigger hypoxia/reoxygenation (H/R). Forced cytoplasmic overexpression of ref-1 suppressed H/R-induced oxidative stress (H(2)O(2) production), NF-kappaB activation, and apoptosis, and also mitigated rac1-regulated H(2)O(2) production and NF-kappaB transcriptional activity. We conclude that inhibition of oxidative stress is another mechanism by which ref-1 protects against apoptosis, and that this is achieved through modulation of cytoplasmic rac1-regulated ROS generation. This suggests a novel extra-nuclear function of ref-1.

Molecular cloning of kpcA gene encoding a Kex2p-like endoprotease from Aspergillus nidulans

We cloned and sequenced a gene, kpcA (Kex2p-like proprotein convertase A), from a genomic library of Aspergillus nidulans. The kpcA gene encodes an 820-residue protein, named KpcA, which contains a putative subtilisin-like catalytic domain (residues 136-466) homologous to that of the subtilisin serine protease family. KpcA shows 56, 73, and 47% amino acid identities with Saccharomyces cerevisiae Kex2p, Aspergillus niger KexB, and mouse furin within the subtilisin-like catalytic domain, respectively. The sequences around the proposed active site Asp, His, and Ser residues of KpcA are similar to those of other Kex2p family members. The KpcA mRNA transcript with an expected size of approximately 2.8 kb was detected in A. nidulans. The substrate specificity of KpcA, expressed in CHO cells, is similar to that of A. niger KexB and yeast Kex2p. We conclude that KpcA is a resident Kex2p-like proprotein that processes endoprotease in A. nidulans.

Effect of high blood flow on the expression of endothelial constitutive nitric oxide synthase in rats with femoral arteriovenous shunts

The effect of high blood flow on the expression of endothelial nitric oxide synthase has been investigated in the femoral arteriovenous shunt (AVS) rats created by inserting U-shaped polyurethane tubes in the left femoral arteries and veins. Three days after inserting the femoral AVS, the mean aortic blood flow rate in the abdominal aorta of the AVS rats was about 2.0 times higher than that in the control rats (110.0 +/- 8.4 ml/min vs 52.7 +/- 2.7 ml/min, p < 0.001). The competitive reverse transcriptase-polymerase chain reaction (RT-PCR) data revealed that the mRNA expression level of the endothelial constitutive nitric oxide synthase (ecNOS) was increased in the aortas of the femoral AVS rats compared to that in the control rats. Western blot analysis using a monoclonal antibody against ecNOS revealed that the ecNOS protein levels were markedly increased in the aortas of femoral AVS rats, but ecNOS protein levels in aortas without endothelium were not significantly increased. Inducible nitric oxide synthase (iNOS) protein was not expressed in the aortic tissues with and without endothelium in the control rats. This iNOS expression was not increased by the high blood flow in the femoral AVS rats. These findings suggest that high blood flow could up-regulate the expression levels of ecNOS mRNA and proteins in femoral arteriovenous shunt rats.

Effect of Korean red ginseng on blood pressure and nitric oxide production

AIM

To investigate the effect of crude saponin and nonsaponin fraction of Korean red ginseng (KRG) on the blood pressure and nitric oxide (NO) production in the conscious rats and cultured endothelial cell line, ECV 304 cells.

METHODS

Systolic blood pressure and heart rate were monitored in the conscious rats. Nitric oxide levels and the expression of nitric oxide synthase were measured by a spectrophotometric assay using Griess reagents and Western blotting, respectively. Nitric-oxide synthase activity was measured based on the conversion rate of [3H]arginine to [3H]citrulline.

RESULTS

Systolic blood pressure was decreased by crude saponin (100 mg/kg, i.v.) of KRG in the conscious control and one-kidney, one-clip Goldblatt hypertensive (1K, 1C-GBH) rats. The hypotensive effect induced by crude saponin of KRG reached maximum at 2-4 min and slowly recovered after 20 min to the initial level in both groups. Crude saponin of KRG induced tachycardia in the conscious rats but induced bradycardia in the anesthetized rats. In contrast to crude saponin of KRG, hypotensive effect induced by saponin-free fraction was minimal. Nitric oxide concentrations were increased by the treatment of crude saponin in conscious rats as well as in the cultured ECV 304 cells. The protein expression level of endothelial constitutive nitric-oxide synthase (eNOS) in the aorta of rats was not increased by crude saponin (100 mg/kg, i.p. for 3 d). However, nitric-oxide synthase activity was increased by crude saponin of KRG in the aortic homogenate of rats.

CONCLUSION

The hypotensive effect of red ginseng is mainly due to saponin fraction of KRG in the conscious rats, and this effect may be due to an increase in the nitric-oxide production by KRG.

Effect of Korea red ginseng on the blood pressure in conscious hypertensive rats

The change of blood pressure and heart rate after intravenous injection of Korea red ginseng (KRG) were studied in the conscious normotensive and one-kidney, one-clip Goldblatt hypertensive (1K, 1C-GBH) rats. Crude saponin (CS) of KRG (50, 100 mg/kg i.v.) induced a hypotensive effect and bradycardia in a dose-dependent manner in the anesthetized rats. On the other hand, CS of KRG (100 mg/kg) induced a hypotensive effect and reflex tachycardia in the conscious rats. Saponin-free fraction (SFF) of KRG did not affect them in the anesthetized normotensive rats (P>.05). The maximal hypotensive effect by CS of KRG in the conscious 1K, 1C-GBH hypertensive rats and L-nitroarginine methyl ester (L-NAME, 40 mg/kg)-treated conscious hypertensive rats was not different from that of conscious normotensive rats (Delta 31.6+/-6.3, Delta 27.5+/-5.8 vs. Delta 26.7+/-4.3 mmHg, P>.05). However, pretreatment of L-NAME significantly inhibited the reflex tachycardia by CS of KRG (70.8+/-7.0 vs. 30.6+/-15.0 bpm, P<.05). Hemolysate-sensitive nitric oxide (NO) current by the CS of KRG was greater than that of the SFF of KRG (651.9+/-128.2 pA for CS and 164.9+/-92.5 pA for SFF, P<.001). These findings suggest that KRG has a hypotensive effect and its effect may be due to saponin fraction of KRG in the conscious rats. The releasing effect of NO of KRG, like NO donor, may be partly contributed to the hypotensive effect of KRG.

The Effect of Poly(methyl vinyl ether-alt-maleic acid) Stabilizer on the Stability of Polyaniline-Poly(methyl vinyl ether-alt-maleic acid) Dispersions

The polyaniline (PANI) dispersions have been prepared in acidic aqueous media by oxidative dispersion polymerization in the presence of a polymeric stabilizer. The polymeric stabilizer used in this study is the poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) which contains acid groups (-COOH). The PANI-PMVEMA particles have a uniform size and a spherical shape. The PANI-PMVEMA dispersions show almost no desorption of the PMVEMA, even though the sonication at 500 W for 20 min and the centrifugation at 500 rpm for 60 min are performed 10 times. The existence of the PMVEMA on the surface is confirmed by X-ray photoelectron spectroscopy. The dispersion stability of the PANI-PMVEMA dispersions is extensively influenced by zeta potential which was governed by the acid group (-COOH) of the PMVEMA on the PANI-PMVEMA particle surface. Copyright 2000 Academic Press.

Serologic responses of Korean soldiers serving in malaria-endemic areas during a recent outbreak of Plasmodium vivax

Anti-Pv200 antibody levels were assessed in samples from endemic areas of Plasmodium vivax malaria in the Republic of Korea (ROK), using an indirect enzyme-linked immunosorbent assay (ELISA) method. Asymptomatic carriers of P. vivax were detected using nested polymerase chain reaction (PCR) of blood samples. Anti-Pv200 antibody levels in 20 vivax malaria patients (optical density +/- standard deviation [OD +/- SD] values 1.85 +/- 0.29 of IgG isotype and 1.33 +/- 1.33 of IgM isotype) were markedly higher than those of uninfected, malaria-naive controls (0.08 +/- 0.16 of IgG isotype and 0.04 +/- 0.04 of IgM isotype). Antibody levels for 7 out of 8 soldiers with a recent malaria infection were sustained above the cut-off values for 4 months after successful treatment. Analysis of serum collected from 40 healthy, asymptomatic soldiers who had a P. vivax malaria attack within 3 months after our sampling, revealed 11 antibody-positive samples (27.5%), compared to 5 positive samples (12.5%) collected from a random selection of 40 soldiers. Among a larger pool of 1,713 soldiers who had served in high-risk areas for P. vivax transmission, 15% were antibody positive. Among 1,000 blood samples from asymptomatic soldiers who had served in the high-risk areas, 4 samples (0.4%) were parasite positive, as determined by nested PCR. Our results show that anti-Pv200 antibody levels can provide useful information in the late diagnosis of P. vivax malaria infection in a previously naive population and also in large seroepidemiologic studies. Furthermore, our results suggest that asymptomatic P. vivax carriers could be important in the current outbreak of malaria in Korea.

Alpha1-adrenoceptors involvement in painful diabetic neuropathy: a role in allodynia

To investigate whether alpha1-adrenoceptors are involved in pain behaviors in streptozotocin (STZ)-induced diabetic rats, we measured the effects of phenylephrine or prazosin on allodynia in the diabetic rats. Phenylephrine aggravated allodynia, while prazosin alleviated allodynia in the diabetic rats. We also measured alpha1-adrenoceptors gene expression or density of [3H]-prazosin binding sites in the dorsal root ganglia (DRG) and spinal cord in painful diabetic rats. Alpha1-adrenoceptors mRNA and density of [3H]prazosin binding sites were increased in the DRG of the diabetic rats, however there were no significant differences in alpha1-adrenoceptors expression in the spinal cord between the control and diabetic rats. These results suggest increased alpha1-adrenoceptors in the DRG may play a role in the pathogenesis of painful diabetic neuropathy.

The homeodomain transcription factor NK-4 acts as either a transcriptional activator or repressor and interacts with the p300 coactivator and the Groucho corepressor

NK-4 (tinman) encodes an NK-2 class homeodomain transcription factor that is required for development of the Drosophila dorsal mesoderm, including heart. Genetic evidence suggests its important role in mesoderm subdivision, yet the properties of NK-4 as a transcriptional regulator and the mechanism of gene transcription by NK-4 are not completely understood. Here, we describe its properties as a transcription factor and its interaction with the p300 coactivator and the Groucho corepressor. We demonstrate that NK-4 can activate or repress target genes in cultured cells, depending on functional domains that are conserved between Drosophila melanogaster and Drosophila virilis NK-4 genes. Using GAL4-NK-4 fusion constructs, we have mapped a transcriptional activation domain (amino acids 1-110) and repression domains (amino acids 111-188 and the homeodomain) and found an inhibitory function for the homeodomain in transactivation by NK-4. Furthermore, we demonstrate that NK-4-dependent transactivation is augmented by the p300 coactivator and show that NK-4 physically interacts with p300 via the activation domain. In addition, cotransfection experiments indicate that the repressor activity of NK-4 is strongly enhanced by the Groucho corepressor. Using immunoprecipitation and in vitro pull-down assays, we show that NK-4 directly interacts with the Groucho corepressor, for which the homeodomain is required. Together, our results indicate that NK-4 can act as either a transcriptional activator or repressor and provide the first evidence of NK-4 interactions with the p300 coactivator and the Groucho corepressor.

Hepatic ischemia/reperfusion in rats induces iNOS gene transcription by activation of NF-kappaB

It has been known that many immediately early genes are expressed during ischemia/reperfusion (I/R) injury. Here, employing a model of hepatic I/R, we show that inducible nitric oxide synthase (iNOS) is induced via the activation of nuclear factor kappaB (NF-kappaB) after I/R in rat liver. When liver was subjected to ischemia followed by reperfusion, but not ischemia alone, an NF-kappaB complex composed of p50/p65 heterodimer and p50 homodimer was rapidly activated within 1 h and remained elevated for up to 3 h, and then tended to decline after 5 h of reperfusion. Also, the expression of iNOS mRNA was initiated after 1 h and continued to increase after 5 h of reperfusion during the time course studied. This upregulated iNOS mRNA expression coincides with increased iNOS enzyme activity and NF-kappaB binding activity after hepatic I/R. Administration of N-acetylcysteine (NAC, 20 mg/kg i.v. 10 min before reperfusion), an antioxidant, not only significantly inhibited the expression of iNOS mRNA but also blocked upregulated NF-kappaB binding activity after reperfused liver. These results suggest that NF-kappaB is activated by oxidative stress during hepatic I/R and may play a significant role in the induction of the iNOS gene.