Determination of process-related impurities in N-acetylglucosamine prepared by chemical and enzymatic methods: structural elucidation and quantification

β-N-acetylglucosamine (β-AG) is a monosaccharide distributed widely in living organisms with various pivotal roles. The presence of particulates and impurities can affect the safety and efficacy of a product for its intended duration of use. Thus, the current study was carried out to identify and quantify the potentially-harmful process related impurities; namely α-N,6-diacetylglucosamine (α-DAG) and α-N-acetylglucosamine (α-AG), derived from the chemical and enzymatic synthesis of β-AG. The impurities were characterized using a high resolution mass spectrometry, a nuclear magnetic resonance spectroscopy, and liquid chromatography-tandem mass spectrometry (LC/MS/MS). The developed method showed a good linearity (R (2) ≥ 0.998), satisfactory precision (≤6.1 % relative standard deviation), intra- and inter-day accuracy (88.20-97.50 %), extraction recovery (89.30-110.50 %), matrix effect (89.70-105.20 %), and stability (92.70-101.60 %). The method was successfully applied to determine the level of α-DAG that was 3.04 and 0.07 % of the total β-AG, following chemical and enzymatic methods, respectively. It can be concluded that the enzymatic rather than the chemical method is more efficient for the synthesis of β-AG. Characterization of impurities heeds the signal for acquiring and evaluating data that establishes biological safety.

The Halicylindramides, Farnesoid X Receptor Antagonizing Depsipeptides from a Petrosia sp. Marine Sponge Collected in Korea

Three new structurally related depsipeptides, halicylindramides F-H (1-3), and two known halicylindramides were isolated from a Petrosia sp. marine sponge collected off the shore of Youngdeok-Gun, East Sea, Republic of Korea. Their planar structures were elucidated by extensive spectroscopic data analyses including 1D and 2D NMR data as well as MS data. The absolute configurations of halicylindramides F-H (1-3) were determined by Marfey's method in combination with Edman degradation. The absolute configurations at C-4 of the dioxyindolyl alanine (Dioia) residues of halicylindramides G (2) and H (3) were determined as 4S and 4R, respectively, based on ECD spectroscopy. The C-2 configurations of Dioia in 2 and 3 were speculated to both be 2R based on the shared biogenesis of the halicylindramides. Halicylindramides F (1), A (4), and C (5) showed human farnesoid X receptor (hFXR) antagonistic activities, but did not bind directly to hFXR.

Abstract P3-01-08: Sentinel lymph node biopsy alone after neoadjuvant chemotherapy in patients with cytologically proven node-positive breast cancer

Background

The purpose of this study was to identify the feasibility and accuracy of sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) in patients with axillary lymph node (ALN) metastasis at diagnosis.

Methods

This is a retrospective study of 332 patients who were diagnosed with invasive breast cancer and ALN metastasis and treated with NAC followed by curative surgery at Samsung Medical Center between January 2007 and December 2013. Patients were classified into five groups according to surgical procedure for the ALNs and pathologic results; group 1, patients with negative SLN status and no further dissection was performed; group 2, patients with negative SLN status undergoing further axillary lymph node dissection (ALND); group 3, patients with positive or undetected SLNs undergoing further ALND; group 4, patients without residual axillary metastasis undergoing complete ALND; and group 5, patients with pathologic nodal positive disease undergoing ALND.

Results

Sentinel lymph nodes identification rate after NAC was 99.1% and false negative rate was 24.1%. The median number of retrieved SLNs was 4 (range, 1–10). There was no difference in the overall survival among the groups (p=0.06). There was no significant difference in the disease-free survival rate between the SLNB only and complete ALN dissection groups who revealed a pathologic complete node response (79.6% versus 80.5%) and the rate of axillary recurrence demonstrated no significant differences among the groups. (p=0.225) There was a statistical difference of recurrence between group 1 versus 2, and group 1 versus 4 in hormone receptor-negative patients. (p=0.027)

Conclusion

SLNB after NAC in breast cancer patients with initial ALN metastasis may help identify downstaging to negative nodal status and thereby reduce the surgical morbidity by avoiding standard ALN dissection.

Citation Format: Park S, Ryu JM, Paik H-J, Yi HW, Bae SY, Lee SK, Kil WH, Kim SW, Lee JE, Nam SJ. Sentinel lymph node biopsy alone after neoadjuvant chemotherapy in patients with cytologically proven node-positive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-08.

Abstract P1-12-09: The oncologic effect of a gonadotropin releasing hormone (GnRH) agonist for ovarian protection during breast cancer chemotherapy

Background: Recently, chemotherapy with a GnRH agonist was reported to protect against ovarian failure. This study was aimed at determining the oncologic effect of a GnRH agonist concurrent with chemotherapy for breast cancer patients.

Patients and Methods: A total of 1189 patients aged 20 to 40 years with stage I to III breast cancer who received (neo or adjuvant) chemotherapy from five hospitals in Korea from 2002 to 2012 were reviewed. A gonadotropin releasing hormone (GnRH) agonist was given to 410 patients for ovarian protection during chemotherapy (GnRH agonist group), and 779 patients received chemotherapy without ovarian protection (Chemotherapy alone group). A matching strategy was used to create matched sets of two groups by age, stage, hormone receptor status, Her2/neu status, neo or adjuvant chemotherapy, and institute.

Results: Survival analysis using Cox regression showed that the GnRH agonist group had better distant metastatic-free survival (HR=0.65, 95%CI 0.44-0.97) outcomes but similar disease free survival (HR=0.78, 95% CI 0.57-1.08) compared with the chemotherapy alone group. The survival benefit was significant for hormone receptor positive, Her2/neu negative breast cancer on distant metastasis (HR=0.44, 95% CI 0.20-0.99) and disease free survival (HR0.47 95% CI 0.23-0.93).

Conclusion: Ovarian protection using a GnRH agonist can be safely considered for premenopausal breast cancer patients for whom chemotherapy is planned.

Citation Format: Kim HJ, Lee MH, Lee JE, Park SH, Lee ES, Kang Y-J, Lee JH, Shin HN, Kim SI, Im SA, Ahn SH, Lee KS, Sohn J, Han W, Nam SJ. The oncologic effect of a gonadotropin releasing hormone (GnRH) agonist for ovarian protection during breast cancer chemotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-12-09.

Abstract P2-08-19: Prognostication of HER family gene expression collaborate with ESR1 expression in patients with triple negative breast cancer

Background: Triple-negative breast cancer (TNBC) consists of heterogeneous sub-population. Although many investigators made an effort to categorize and classify TNBCs using genetic expressions, it is still needed to be defined for prognostication Traditionally, HER family genes have been known to contribute mammalian glands formation and breast cancer generation as well as ESR gene. Moreover, target agents for HER family genes have been already developed. Accordingly, we investigated the expression profiles of HER family genes with ESR in patients with TNBC to categorize into sub-types and determine the prognostic value of HER family genes in search of clinical implications.

Methods : We investigated the results of the nCounter expression assay (NanoString®) for ERBB1, ERBB2, ERBB3, ERBB4 and ESR1 using mRNA extract from paraffin-embedded tumor tissues in 203 patients diagnosed as TNBC. We used the results of nCounter expression assay using 84 TNBC tissues for validation and 52 breast cancer tissues diagnosed as other subtypes to control the expression assay results of these five genes.

Results: Two-hundred and three patients were diagnosed as TNBC from 2000 to 2004 and received adjuvant chemotherapy after curative surgery. Eighty-four TNBC patients for validation set and 52 patients diagnosed as other subtypes for control set were selected from the patients diagnosed as breast cancer from 2005 to 2010 and received curative surgery. Through analyzing 5 genes using the nCounter expression profiles from 203 TNBC tissues, we found that increased expression of ERBB4 was associated with poor prognosis by survival analysis (5 year disease recurrence free survival (DRFS), low vs. high expression [cut-off: median]: 90.1% vs. 80.2%; p =.002). This trend was still remained in validation set composed of TNBC (5 year DRFS, low vs. high expression [cut-off : median]: 61.1% vs. 44.0%), whereas was not observed in other subtypes of breast cancer (44.4% vs. 80.8%). The Kaplan-Meier estimates of the rates of 5 year DRFS in the subgroups classified according to the level of 5 genes expression showed that the group of higher expression of all HER family genes and lower expression of ESR1 gene had dismal prognosis rather than other groups in patients with TNBC (5 year DRFS, this group vs. others: 50.0% vs. 88.2%; p <.001). In a multivariate Cox regression model, ERBB4 expression identified as a useful marker for predicting long-term prognosis in patients with TNBC although other HER family genes and ESR1 expressions did not predict prognosis of TNBC with statistical significance (Table 1).

Impact of the m RNA expression levels of ERBB family and ESR1 on DRFS Hazard Ratio95% CIP-valueStage  <.001I1.0NA IIA1.200.40-3.57 IIB3.751.20-11.74 IIIA5.461.55-9.24 IIIC59.9214.30-251.12 EGFR  .167Low1.0NA High1.690.80-3.55 ERBB2  .057Low1.0NA High0.430.18-1.03 ERBB3  .061Low1.0NA High2.200.96-5.04 ERBB4  .016Low1.0NA High2.681.20-5.95 ESR1  .113Low1.0NA High0.570.28-1.15 

Conclusions: The expression profile of HER family genes could be used as a prognostic marker in patients with TNBC. Further study is needed to identify the expression profiles of HER family gene as predictive marker of HER targeting treatment in patients with TNBC.

Citation Format: Kim J-Y, Ahn T, Jung HH, Park K, Do I-G, Kil WH, Kim SW, Lee JE, Nam SJ, Ahn JS, Park YH, Im Y-H. Prognostication of HER family gene expression collaborate with ESR1 expression in patients with triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-19.

Abstract P1-08-08: Heterozygous germline mutations in RAD50 among Korean patients with high-risk breast cancer negative for BRCA1/2 mutation

Background: The MRE11-RAD50-nibrin (MRN) complex participates in pathways of double-strand break induced DNA repair and cell cycle checkpoint control. RAD50 interacts with the MRE11 and NBS proteins, is involved in the maintenance of genomic integrity. The association of RAD50 mutation and breast cancer susceptibility has been reported in European patients. However, the impact of RAD50 mutation on a breast cancer predisposition among Koreans remains uncertain. In the current analysis, we evaluated the incidence of RAD50 mutations among Korean patients with non-BRCA1/2 high-risk breast cancer.

Materials and Methods: A total of 247 Korean patients with high-risk breast cancer who tested negative for BRCA1/2 mutation were enrolled. The criteria for high-risk breast cancer were as follows: having a family history of breast or ovarian cancer in any relative; diagnosed at age 40 years or younger; bilateral breast cancer; and male breast cancer. All participants were screened for BRCA1/2 mutations using fluorescent-conformation sensitive capillary electrophoresis (F-CSCE) and traditional sequencing. The entire RAD50 gene of each patient was sequenced using F-CSCE. In silico analyses of the RAD50 variants was performed using PolyPhen-2 and SIFT.

Results: There were two novel deleterious mutations in RAD50 (p.Q426X, p.E1271del). These mutations were found in two patients, including one with p.Q426X and the other with p.E1271del. Besides, five sequence variants in RAD50 were identified: four exonic variants (p.I118T, p.R486C, p.L1264F, and p.R1279H) and one intronic variant (c.1246-11T>C). Among the four missense variants, p.R486C and p.L1264F were variants predicted to be deleterious by in silico analyses.

Conclusions: We found protein-truncating mutations in RAD50 gene in a small proportion of Korean patients with high-risk breast cancer. The contribution of the mutation to the development of breast cancer should be clarified in further researches.

Citation Format: Kim H, Cho D-Y, Choi DH, Jung GH, Shin I, Park W, Huh SJ, Nam SJ, Lee JE, Gil WH, Kim SW. Heterozygous germline mutations in RAD50 among Korean patients with high-risk breast cancer negative for BRCA1/2 mutation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-08-08.

Abstract P1-11-01: Depression and anxiety after adjuvant ovarian function suppression in premenopausal breast cancer patients

Purpose

The results of the Suppression of Ovarian Function Trial (SOFT) and the Tamoxifen and Exemestane Trial (TEXT) showed that ovarian function suppression (OFS) in premenopausal early breast cancer patients improves disease control. However, mood swings after OFS is one of the chief complaints to make patients stop undergoing endocrine therapy. Studies about complications of OFS in breast cancer patients are not established well. We designed this randomized controlled trial to evaluate psychological functioning of patients after undergoing adjuvant OFS by goserelin.

Patients and Methods

We randomly assigned 64 premenopausal women with hormone receptor positive early breast cancer to the tamoxifen or tamoxifen plus goserelin group for a period of 1 year. Participants were screened for depression and generalized anxiety disorder using Hamilton Rating Scale for Depression (HAMD), Hamilton Rating Scale for Anxiety (HAM-A), Anxiety Sensitivity Index (ASI) and Albany panic and phobia questionnaire (APPQ) at baseline, 6 months and 12 months. Brain-derived Neurotrophic Factor (BDNF) levels were measured, as well. The results were analyzed by using a linear mixed model and a generalized linear mixed model.

Results

Thirty two patients were distributed in each group, equally. Linear mixed-mixed model analyses revealed that, compared with HAM-A scores of each group at baseline, HAM-A scores at 12 months showed increments (p=0.0078). Among HAM-A questions, Questions for intellectual, sensory and autonomic status were scored significantly high at 12 months (p=0.0018, p=0.0132, p=0.0006). Platelet BDNF levels reported a statistically significant rise at 12 months (p=0.0006). There was no significant time-by-study group effect in all scales.

Conclusion

Compared with the patients without OFS, patients with Goserelin showed no difference in anxiety or depression scales. Thought the levels of anxiety of each group at 12 months were increased, they do not indicate medical interventions. Patients with increased levels of BDNF at 12 months are expected to have good recovery from anxious and depressive symptoms.

Citation Format: Yi HW, Nam SJ, Kim SW, Lee JE, Lee SK, Bae SY, Park S, Paik H-J, Ryu JM. Depression and anxiety after adjuvant ovarian function suppression in premenopausal breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-11-01.

Abstract P5-12-08: Time course of changes in serum FSH, serum estradiol, and menstruation in premenopausal patients with breast cancer taking tamoxifen after completing chemotherapy: A report from the ASTRRA study

BACKGROUND

Ovarian suppression with tamoxifen after chemotherapy is a promising therapeutic approach, particularly in young, high-risk breast cancer patients. Assessment of restoration of ovarian function is important with respect to the initiation of ovarian suppression.

METHODS

In total, 1289 women who remained or resumed premenopausal status after chemotherapy were randomized to receive 5 years of tamoxifen or 5 years of tamoxifen plus 2 years of ovarian suppression. Prospectively collected hormone data were available for 24 months after completing chemotherapy for 267 breast cancer patients without ovarian suppression.

RESULTS

At 6 months, a premenopausal status was identified in 56.6%, 36%, and 16.2% of patients using serum FSH, E2, and with menstruation bleeding, respectively, and about 30% more women achieved ovarian restoration using all three parameters during the 24-month follow-up. Ovarian function restoration differed significantly according to age group (log-rank, P<0.001 for all definitions). At 6 months, the distribution of patients according to hormone levels was as follows: group 1 (FSH <30 mIU/ml, E2 >20 pg/ml), 28.0%; group 2 (FSH <30 mIU/ml, E2 ≤20 pg/ml), 28.4%; group 3 (FSH ≥30 mIU/ml, E2 >20 pg/ml), 8.0%; and group 4 (FSH ≥30 mIU/ml, E2 ≤20 pg/ml), 35.6%. During the 24-month follow-up, the prevalence of menstruation restoration was higher in group 1 (71.6%) than in the other three groups. Restoration of serum E2 and menstrual bleeding occurred in 44% and 33% of patients in group 2, respectively; the corresponding percentages in group 4 were 40.6% and 28.7% (P<0.001).

CONCLUSIONS

Ovarian function should be monitored using serum FSH, serum E2, and menstruation history for at least 24 months after completing chemotherapy during tamoxifen treatment to establish eligibility for ovarian suppression.

Citation Format: Kim HJ, Ahn SH, Nam SJ, Park SH, Ro JS, Im SA, Jung YS, Noh WC. Time course of changes in serum FSH, serum estradiol, and menstruation in premenopausal patients with breast cancer taking tamoxifen after completing chemotherapy: A report from the ASTRRA study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-12-08.

The Protective Effects of Alisol A 24-Acetate from Alisma canaliculatum on Ovariectomy Induced Bone Loss in Vivo

Alisma canaliculatum is a herb commonly used in traditional Korean medicine, and has been shown in scientific studies to have antitumor, diuretic hepatoprotective, and antibacterial effects. Recently, the anti-osteoclastogenesis of alisol A 24-acetate from Alisma canaliculatum was investigated in vitro. However, the influence of alisol A 24-acetate on osteoporosis in animals has not been investigated. The present study was undertaken to investigate the anti-osteoporotic effect of alisol A 24-acetate on bone mass in ovariectomized (OVX) mice and to identify the mechanism responsible for its effects. OVX mice were treated daily with 0.5 or 2 μg/g of alisol A 24-acetate for a period of six weeks. It was found that these administrations significantly suppressed osteoporosis in OVX mice and improved bone morphometric parameters. The serum estradiol, bone alkaline phosphatase levels, regulatory T/Th17 cell numbers were significantly increased by alisol A 24-acetate as compared with untreated OVX mice. In addition, TRAP activity was inhibited by alisol A 24-acetate in OVX mice. These results suggest alisol A 24-acetate effectively prevents bone loss in OVX mice, and that it can be considered a potential therapeutic for the treatment of postmenopausal osteoporosis.

Nocarimidazoles A and B from a Marine-Derived Actinomycete of the Genus Nocardiopsis

Chemical investigation of a marine-derived actinomycete isolated from marine sediments collected off the coast of southern California and identified as a Nocardiopsis sp. (strain CNQ115) led to the isolation of two new 4-aminoimidazole alkaloids, nocarimidazoles A (1) and B (2). The chemical structures of nocarimidazoles A and B were assigned by interpretation of NMR spectroscopic data and through methylation to yield monomethyl and dimethyl derivatives. Nocarimidazoles A and B possess a 4-aminoimidazole ring combined with a conjugated carbonyl side chain, which is rarely found in microbial secondary metabolites.

Monanchosterols A and B, bioactive bicyclo[4.3.1]steroids from a Korean sponge Monanchora sp

Chemical investigation of a Korean marine sponge, Monanchora sp., led to the isolation of three new steroids (1-3). Compounds 1 and 2, designated as monanchosterols A and B, respectively, represent the first examples of steroids possessing the bicyclo[4.3.1] A/B ring system from a natural source. Compounds 1-3 were investigated for their anti-inflammatory activity by evaluating their inhibitory effects on the mRNA expression of IL-6, TNF-α, and COX-2 in the LPS-stimulated murine RAW264.7 macrophage cells. Compounds 2 and 3 exhibited significant inhibitory effects on the mRNA expression of IL-6 without notable cytotoxicity to the cells in a dose-dependent manner.

Acredinones A and B, voltage-dependent potassium channel inhibitors from the sponge-derived fungus Acremonium sp. F9A015

Two new benzophenones, acredinones A (1) and B (2), were isolated from a marine-sponge-associated Acremonium sp. fungus. Their chemical structures were elucidated on the interpretation of spectroscopic data. The structure of 1 was confirmed by palladium-catalyzed hydrogenation, followed by spectroscopic data analysis. Acredinones A (1) and B (2) inhibited the outward K(+) currents of the insulin secreting cell line INS-1 with IC50 values of 0.59 and 1.0 μM, respectively.

Utilization of circular dichroism experiment to distinguish acanthoside D and eleutheroside E

Two lignan glycosides, acanthoside D (1) (=liriodendrin, (+)-syringaresinol di-O-β-D-glucopyranoside) and eleutheroside E (2) have been confused each other for so long time, and hard to be distinguished each other. Now, this two compounds need to be defined properly so that all the commercial mistakes and confusions should not be made. They have identical planar structures except for the configurations at C-7 and C-8 in each structure according to the chemistry database, SciFinder(®). The systematic name of acanthoside D is [(1S,3aR,4S,6aR)-tetrahydro-1H,3H-furo[3,4-c]furan-1,4-diyl]bis(2,6-dimethoxy-4,1-phenylene) bis-β-D-glucopyranoside (1), and the name of eleutheroside E is [(1R,3aR,4S,6aS)-tetrahydro-1H,3H-furo[3,4-c]furan-1,4-diyl]bis(2,6-dimethoxy-4,1-phenylene) bis-β-D-glucopyranoside (2). The differences at two chiral centers do not make any differences in the NMR spectra. Thus, the circular dichroism were utilized to dissolve this difficult problem. Acanthoside D (1) showed a positive Cotton effect at 200 nm, whereas eleutheroside E (2) exhibited a negative cotton effect at 200 nm. The absolute structure of acanthoside D was also confirmed by X-ray crystallography.

Induction of fibronectin by HER2 overexpression triggers adhesion and invasion of breast cancer cells

Fibronectin (FN), an extracellular matrix ligand, plays a pivotal role in cell adhesion, migration, and oncogenic transformation. Aberrant FN expression is associated with poor prognoses in various types of cancer, including breast cancer. In the current study, we investigated the relationship between FN induction and HER2 expression in breast cancer cells. Our results showed that the level of FN expression increased in response to HER family ligands, EGF and TGF-α in a time- and dose-dependent manner. On the other hand, EGF-induced FN expression decreased in response to trastuzumab, which is a HER2-targeted monoclonal antibody. However, EGF-induced FN expression was not affected by trastuzumab in JIMT-1 breast cancer cells, which are trastuzumab insensitive cells. Next, we introduced the HER2 gene into MDA-MB231 cells to verify the relationship between FN and HER2. The level of FN expression significantly increased in HER2-overexpressed MDA-MB231 cells. In contrast, the induction of FN by HER2 was significantly decreased in response to trastuzumab treatment. In addition, the induction of FN by HER2 was down-regulated by the MEK 1/2 specific inhibitor, U0126. Using conditioned culture media of vec- and HER2-overexpressed MDA-MB231 cells, we observed the cell morphology, adhesion, and invasion of MDA-MB231 cells. Interestingly, in conditioned culture media of HER2-overexpressed MDA-MB231 cells, the cell morphology was altered, and adhesion and invasion of MDA-MB231 cells significantly increased. In addition, our results showed that recombinant human FN augmented cell adhesion and invasion of MDA-MB231 cells while these inductions decreased in response to an FN inhibitor. Therefore, we demonstrated that the induction of FN by HER2 triggers cell adhesion and invasion capacities.

Visualization of endogenous and exogenous hydrogen peroxide using a lysosome-targetable fluorescent probe

Reactive oxygen species (ROS) play crucial roles in diverse physiological processes; therefore, the efficient detection of ROS is very crucial. In this study, we report a boronate-based hydrogen peroxide (H2O2) probe having naphthalimide fluorophore. This probe also contained a morpholine moiety as a directing group for lysosome. The recognition property indicated that the probe exhibited high selectivity towards H2O2 not only in the solution but also in the living cells. Furthermore, it was used to monitor the level of endogenous and exogenous H2O2. These results support that the probe can function as an efficient indicator to detect H2O2.