Remifentanil requirement for acceptable intubation conditions with two different doses of ketamine without a neuromuscular blocking agent in pediatric patients

OBJECTIVE

The optimal remifentanil concentration for improving intubation conditions when intubation is performed without neuromuscular blocking agents (NMBAs) but with ketamine as an induction agent remains unknown. Here, we aimed to identify the effective bolus doses of remifentanil required to achieve acceptable intubation conditions upon anesthesia induction with 1 or 2 mg/kg ketamine without NMBAs.

PATIENTS AND METHODS

In this prospective, double-blinded, randomized up-down sequential allocation study, we enrolled pediatric patients aged 3-12 years undergoing general anesthesia for inguinal hernia surgery. The patients were randomly allocated to one of two groups to receive either ketamine 1.0 mg/kg (K1 group) or 2.0 mg/kg (K2 group) intravenously until seven success-failure pairs were achieved. The remifentanil dose for each patient was determined using the modified Dixon's up-and-down method with an initial dose of 2.5 μg/kg and a step size of 0.5 μg/kg.

RESULTS

In total, 51 patients (22 in the K1 group and 29 in the K2 group) were enrolled. The effective dose (ED)50s of remifentanil for obtaining clinically acceptable intubation conditions under anesthesia induction with ketamine but without NMBAs was 3.2 μg/kg in the K1 group and 1.6 μg/kg in the K2 group. High-dose remifentanil with 1 mg/kg ketamine was associated with more severe chest wall rigidity and lower mean blood pressure and heart rate than was low-dose remifentanil with 2 mg/kg ketamine.

CONCLUSIONS

The ED50 of remifentanil required for clinically acceptable intubation conditions with anesthesia induction using 1 mg/kg ketamine without NMBAs in pediatric patients was twice that when using 2 mg/kg ketamine. The combination of 2 mg/kg ketamine and remifentanil was better at preventing chest wall rigidity.

Localization and transient emission properties in InGaN/GaN quantum wells of different polarities within core-shell nanorods

Transient photoluminescence (PL) characteristics and localization phenomena in InGaN/GaN core-shell nanorods (NRs) were investigated from 6 K up to 285 K. The NRs exhibit three well-defined PL bands in the near-UV, blue, and green range ascribed to the emission of quantum well (QW) areas situated at the (1.00) sidewalls, (10.1) top facets, and (00.1) tip, respectively. At low temperature, time-resolved PL shows a fast decay time of about 0.5 ns for the semi- and non-polar QWs, while the polar QWs exhibit at least a twice-longer time. Rapid delocalization of carriers above 50 K indicates shallow potential fluctuations in the QWs. At room temperature, the characteristic fast PL decay time of the three QW bands stabilizes around 300 ps. The slow decaying PL components have different characteristic decay times that are explained by additional localization at basal stacking faults (BSFs), taking into account the quantum confined Stark effect. In addition, narrow excitonic luminescence lines are observed in the BSF-enriched polar QWs, providing direct evidence of the impact of the BSF/QW crossings on the optical properties of the NRs. A PL rise time of about 100 ps does not show any deviation between bands. These findings are suggestive of similar transport mechanisms in temperature equilibrium without inter-facet transport between different QWs. We believe that predictable transient characteristics can play a key role in creating uniform NR ensembles for device applications.

Abstract P3-10-09: The association age-related parity and HER2 over-expression in breast cancer

Backgrounds

Reproductive factors, such as age at menarche, parity, age at first birth, and breast feeding, are known to be associated with risk of breast cancer. Recent studies show the association between the reproductive factors and the molecular subtypes of breast cancer, especially in luminal-like subtypes. Nulliparity is known a risk factor of breast cancer, multiparity is considered a protective factor. However, pregnancy associated breast cancers show the high expression of HER2, Therefore, we hypothesized the number of birth (multiparity) is correlated with the over-expression of HER2.

Methods

We reviewed the database of 2,594 breast cancer patients were over 20 years of age, diagnosed between January 2000 and April 2017 at Korea University of Anam Hospital, Seoul, Korea. According the number of birth, nulliparous (the number of birth = 0; 271 patients), primiparous (the number of birth = 1; 420 patients) and multiparous (the number of birth≥2; 1,903 patients) groups were classified.

Results

The median age (range) of nulliparous, primiparous and multiparous groups was 43 (22-77), 48 (27-87) and 51 (26-86) years (P<0.001). In univariate analysis, the number of birth was associated with the expression of ER and HER2, nulliparous patients showed higher ER positivity (P=0.013) and multiparous patients showed higher HER2 overexpression (P=0.048). There was no association with PR and Ki-67 level. In logistic regression with age, the parity was negative correlation with ER positivity (OR 0.83, 95% CI 0.72-0.95, P=0.010) and positive correlation with HER2 overexpression (OR1.18, 95% CI 1.02-1.36, P=0.021) P=0.009) and multiparity was higher HER2 overexpression (OR 1.41, 95% CI 1.02-1.94, P=0.033). By subgroup analysis with menopausal status, there was statistically significance in only premenopausal women, not in postmenopausal women. In premenopausal women, the parity was negatively associated with ER positivity (OR 0.78, 95%CI 0.64-0.94, P=0.010) and multiparity was associated with HER2 overexpression (OR 1.72, 95%CI 1.12-2.63, P=0.013), there was no difference in HER2 overexpression between nulliparous and primiparous patients.

Conclusion

Parity was associated with ER and HER2 expression, multiparous patients were associated with ER negativity and HER2 overexpression, especially in premenopausal women. This suggests that pregnancy could affect risk of breast cancer, especially in HER2 positive breast cancer subtype (ER- HER2+ tumors), before menopause. We need further investigation and evaluation.

Citation Format: Bae SY, Kim J, You JY, Jung SP, Bae JW. The association age-related parity and HER2 over-expression in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-10-09.

Abstract P3-01-12: Withdrawn

This abstract was withdrawn by the authors.

Abstract P6-08-09: Incidence and risk factors for congestive heart failure in early breast cancer received anthracycline and/or trastuzumab; big-data analysis of Korean health insurance review and assessment service database

Background: Anthracycline (AC) and/or trastuzumab (T) are the most commonly used for neo-/adjuvant therapy for early breast cancer. However, use of those regimens are limited owing to congestive heart failure (CHF). Although reported incidence from pivotal trials is very low and acceptable, no big data-based population study has not been conducted in Koreans yet. The aim of this study was to analyze the incidence, time to occurrence, and risk factors for CHF in patients with early breast cancer, who were treated with AC and/or T therapy, in Korea.

Methods: We used the Health Insurance Review and Assessment Service database and included women with no prior history of CHF who were aged >19 years and diagnosed as having early breast cancer between 2007 and 2016. Only patients who had received breast cancer surgery and AC and/or T therapy were included. Patients with metastatic cancer codes were excluded.

Result: In total, 86,086 patients were included for this analysis. The incidence and median time to occurrence of CHF according to chemotherapy type were, 3.27% and 683.5 days in the AC only group, 6.39% and 374 days in the AC followed by T group, and 4.43% and 286 days in the T with or without non-AC group, respectively.

The multivariate Cox regression analysis revealed that the adjusted hazard ratio (HR) for CHF was increased with older age; in those aged ≥65 years versus <50 years (HR, 2.79; 95% confidence interval [CI], 2.50–3.12). The HR in the AC followed by T group was significantly higher than that in the AC only group (HR, 2.21; 95% CI, 2.05-2.37). The T with or without non-AC group also showed a significantly higher HR than the AC only group (HR, 1.67; 95% CI, 1.37-2.04). CCI scores of ≥2 were significant predictors of CHF; score 2 versus 0 (HR, 1.30; 95% CI, 1.18-1.45), and score ≥3 versus 0 (HR, 1.87; 95% CI, 1.69-2.06). In addition, preexisting medical conditions were significant predictors for CHF: hypertension (HR, 1.58; 95% CI, 1.45-1.72), diabetes (HR, 1.17; 95% CI, 1.07-1.28), and ischemic heart disease (HR, 1.60; 95% CI, 1.45-1.76).

Conclusion: This is the first big data-based population study in Korea on the development of CHF after treatment with AC and/or T. The overall incidence of CHF was 3% to 6%, with a median time to occurrence of 1 to 2 years. Adjusted HR increased with older age, AC followed by T therapy, CCI scores ≥2, and preexisting conditions.

Table 1. Incidence and median time to occurrence of congestive heart failure according to chemotherapy typeChemotherapy typeTotalCHF event (%)Median time to occurenceAC only66,6992,182 (3.27%)683.5AC followed by T17,0621,090 (6.39%)374T ± non-AC2,325103 (4.43%)286

Table 2. Cox proportional hazards model for congestive heart failure, adjusted for age, chemotherapy type, and Charlson comorbidity index scoreVariableP-valueHR95% CIAge (ref <50 years)   50-64 years<0.00011.541.43-1.66≥65 years<0.00012.792.50-3.12Chemotherapy type (ref AC only)   AC folloewed by T<0.00012.212.05-2.37T ± non-AC<0.00011.671.37-2.04Charlson comorbidity index score (ref 0)   10.12061.080.98-1.192<0.00011.301.18-1.45≥3<0.00011.871.69-2.06

Citation Format: Choi JY, Cho EY, Lee JW, Kim JW, Choi YJ, You JY, Bae SY, Jung SP, Cho KR, Park KH. Incidence and risk factors for congestive heart failure in early breast cancer received anthracycline and/or trastuzumab; big-data analysis of Korean health insurance review and assessment service database [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-09.

Abstract P3-14-12: Oncologic outcomes of immediate breast reconstruction after neoadjuvant chemotherapy in breast cancer patients: A matched case control study

Introduction: Although the indication for total mastectomy (TM) with immediate breast reconstruction (IBR) has been expanded, IBR after neoadjuvant chemotherapy (NACT) is still controversy. We assumed that TM with IBR after NACT is feasible surgical treatment in breast cancer patients. Methods: A retrospective review of breast cancer patients who underwent TM with IBR after NACT between 2008 and 2015 at a single center was conducted. These cases were matched by 1:5 to patients who underwent mastectomy alone after NACT. Matching variables included age, clinical T and N staging before NACT, response to NACT, and pathologic staging after NACT. Pathological stage was followed by seventh American Joint Committee on Cancer (AJCC) classification. Results: Overall, 31 patients were identified in the TM with IBR group (Study group) and 85 patients (Control group) were matched. In the study group, 13 (41.9%) patients underwent nipple-sparing mastectomy (NSM) and 18 (58.1%) underwent skin-sparing mastectomy (SSM). Median follow-up duration was 29.2 (7-31) and 38.8 (11-85) months for the study and control group, respectively. Median age was 37.0 (26-57) and 40.0 (24-56) years for the study and control group, respectively. The clinicopathologic characteristics of both groups are summarized in Table1. Disease-free survival (p=0.520), local recurrence-free survival (p=0.610), distant metastasis-free survival (p=0.795), and over survival (p=0.971) did not differ significantly between two groups. Conclusion: TM with IBR after NACT is feasible surgical treatment option in breast cancer patients.

Clinicopathologic characteristicsVariablesControl group (n=85)Study group (n=31)p-valueAge, years (matching variables)  0.890≤3515 (17.7)9 (29.0) 36-5061 (71.8)21 (67.7) 51≥9 (10.6)1 (3.2) BMI, m2/kg  0.13025≤62 (72.9)28 (90.3) 26-3018 (21.2)2 (6.5) 30>5 (5.9)1 (3.2) Histology  0.326Ductal carcinoma in situ2 (2.4)3 (9.7) Invasive ductal carcinoma74 (87.1)28 (90.3) Invasive lobular carcinoma2 (2.4)0 (0) Others7 (8.2)0 (0) Multiplicity  0.063yes19 (22.6)12 (40.0) no65 (77.4)18 (60.0) Lymphovascular invasion  0.161yes33 (39.3)17 (54.8) no51 (60.7)14 (45.2) Nuclear grade  0.317Low10 (11.9)1 (3.3) Intermediate27 (32.1)14 (46.7) High47 (56.0)15 (24.2) Pathologic T stage (matching variable)  0.154T17 (8.2)6 (19.4) T229 (34.1)15 (48.4) T331 (36.5)4 (12.9) T418 (21.2)6 (19.4) Pathologic N stage (matching variable)  0.494N036 (42.4)13 (41.9) N123 (27.1)13 (41.9) N216 (18.8)4 (12.9) N310 (11.8)1 (3.2) Estrogen receptor  0.608positive49 (57.7)15 (48.4) negative36 (42.4)16 (51.6) Progesterone receptor  0.291positive40 (47.1)10 (32.3) negative45 (52.9)21 (67.7) HER2 status  0.345amplification29 (34.1)10 (32.3) not amplification56 (65.9)21 (67.7) Clinical T-stage (matching variable)  0.897cT12 (2.4)1 (3.2) cT231 (36.5)12 (38.7) cT346 (54.1)16 (51.6) cT46 (7.1)2 (6.5) Clinical N stage (matching variable)  0.947cN03 (3.5)1 (3.2) cN120 (23.5)10 (32.3) cN236 (42.4)10 (32.3) cN326 (30.6)10 (32.3) Response (matching variable)  1.000Partial response64 (75.3)27 (29.7) Stable disease21 (24.7)4 (12.9) 

Citation Format: Ryu JM, Lee JE, Kim SW, Yu J, Rayzah M, Lee SK, Mansoor A, Bae SY, Park S, Paik H-J, Kim I, Bang SI, Jeon BJ, Mun G-H, Pyon J-K. Oncologic outcomes of immediate breast reconstruction after neoadjuvant chemotherapy in breast cancer patients: A matched case control study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-14-12.

Abstract P1-02-11: Clinical utility of serial monitoring of circulating tumor DNA (ctDNA)in patients with neoadjuvant chemotherapy (NAC) for locally advanced breast cancer (LABC)

Introduction: Circulating tumor DNA (ctDNA) is a new biomarker which could guide further treatment. Characterization of tumor mutation profiles is required for informed choice of therapy, given that biological agents target specific pathways and effectiveness may be modulated by specific mutations. It would have clinical utility for neoadjuvant setting also. Thus, we assess the potency of ctDNA to predict tumor response to neoadjuvant chemotherapy(NAC) in locally advanced breast cancer(LABC).

Methods: We performed targeted deep sequencing of 30 plasma DNAs and 10 matched germline DNAs from 10 LABC patients. Serial plasma DNAs were collected at diagnosis, after 1st NAC and curative surgery. For the target enrichment, we designed RNA baits covering a total of ~202kb regions of human genome including a total of 83 cancer-related genes. We constructed the sequencing libraries according to the optimized protocol that we recently reported and sequenced on Illumina HiSeq2500 aiming a mean sequencing depth of ~10,000. After excluding unmapped reads, PCR duplicates and off-target reads, the coverage depths for plasma DNA and germline DNA samples were 2,627x and 4,833x on average, respectively. NAC response was measured by residual cancer burden(RCB) score, calculated as a continuous index combining pathologic measurements of primary tumor and nodal metastases for prediction of distant relapse-free survival.

Results: We analyzed ctDNA and primary tumor tissues from 10 patients with LABC scheduled NAC followed by operation in Samsung Medical Center. Of ten LABCs, one excluded from analysis because of angiosarcoma of breast. Five samples were triple-negative breast cancers (BCs), 2 were HER2 positive BCs and others were ER positive BCs. In tumor response, 1 patient had pathologic complete response (pCR), 1 had RCB class I, 4 and 3 patients did RCB class II and III.

Of 83 genes, in analysis of ctDNA at BC diagnosis, we found 2 to 6 mutations in each samples and 3 mutations were detected averagely. Most common mutation was TP53 (6 patients), followed by PIK3CA mutation. By measuring these mutations in serial ctDNA, we found that ctDNA had disappeared after first cycle of NAC in patient with pCR. In two patients with RCB class I, ctDNA had decreased by more than 10 percent (the level of ctDNA(pg/ml): 455.9 to 30.4, 5.8 to 0.0) of primary plasma sample after first NAC. Two patients increased level of ctDNA had tumor response with RCB class III and one patient had distant tumor recurrence within 3 months after curative surgery. However, correlation between the level of ctDNA and initial stage was not observed.

Patient No.Initial stageSurgical stageRCB scoreRCB classct DNA at diagnosis (pg/5ml)ctDNA after 1st NAG (pg/5ml)Tumor recurrence12A11.3331455.930.4No22B00pCR446.60.0No33B2A1.31515.80.0No42A12.132246.255.4No52B11.7972107.811.6No63B3A4.09033401.15075.5Yes73A2B3.92235088.68536.7No

Conclusions: This preliminary result suggests that serial monitoring of ctDNA would be a potiential surrogate marker to predict tumor response and recurrence during NAC in LABC patients. Further results with long-term outcomes are warranted.

Citation Format: Kim J-Y, Park D, Jung HH, Bae SY, Yu JH, Lee SK, Kim SW, Lee JE, Nam SJ, Ahn JS, Im Y-H, Park YH. Clinical utility of serial monitoring of circulating tumor DNA (ctDNA)in patients with neoadjuvant chemotherapy (NAC) for locally advanced breast cancer (LABC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-11.

Abstract P6-09-36: Tamoxifen resistance: EGFR expression in hormone receptor-positive and HER2 negative breast cancer

Purpose: Crosstalk between growth factor receptor tyrosine kinases (RTKs) and the estrogen receptor (ER) represents one of the most important mechanisms of endocrine resistance. EGFR and HER2 have been recognized as prominent factors associated with endocrine resistance. Most previous studies did not identify subgroups by HER2 overexpression and/or included breast cancer with HER2 overexpression. Accordingly, we analyzed HR positive (HR+) tumors without HER2 overexpression (HER2-).

Methods: We analyzed the clinical data of 2,166 patients with HR+HER2- breast tumors, between January 2007 and July 2013.We included only patients who had endocrine therapy with tamoxifen. Immunostaining for EGFR was interpreted as positive when at least 10% of the tumor cells showed moderate to strong membrane staining.

Results: EGFR expression (EGFR+) was present in 109 patients (5%). EGFR expression was significantly associated with more advanced stage and higher grades. In the univariate analyses, EGFR+ tumors were associated with poorer prognosis than EGFR- tumors (5-year DFS, EGFR+ vs. EGFR-, 91.2% vs. 96.6%, P <0.001; 5-year OS, EFGR+ vs EGFR-, 93.1 % vs. 99.4%, P < 0.001). In the multivariate analysis, EGFR+ tumors had a hazard ratio of 2.63 (95% CI 1.14 -6.05) for DFS. EGFR+ tumors had a hazard ratio of 8.8 (95% CI 2.68-132.25) for OS.

Conclusion: EGFR expression could be prognostic factor in hormone receptor-positive and HER2 negative breast cancer, for tamoxifen resistance.

Citation Format: Bae SY, Nam SJ, Lee SK, Kim SW, Lee JE, Yu JH. Tamoxifen resistance: EGFR expression in hormone receptor-positive and HER2 negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-36.

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 P1-11-01: 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 P2-09-19: Zerumbone suppresses IL-1b-induced cell migration and invasion through inhibition of IL-8 expression and MMP3 expression in human triple negative breast cancer cells

Background: Inflammation is a key regulatory process in breast cancer progression and severity. Several studies have demonstrated that prolonged exposure of breast tumor cells to inflammatory cytokines leads to epithelial-mesenchymal transitions (EMT), which is the principle mechanism involved in metastasis and tumor invasion. Disruption of the signaling pathways involved in EMT may therefore provide an effective treatment strategy for currently difficult to treat or untreatable cancers such as TNBC. The interleukin (IL)-1 plays a pivotal role on breast cancer proliferation, invasion and/or inflammation. Here, we investigated the correlation of MMP-3 and IL-8 on IL-1b-induced cell migration and invasion as well as the inhibitory effect of zerumbone on IL-1β-induced MMP-3 and IL-8.

Methods: Triple negative breast cancer cells (Hs578T and MDA-MB231) were cultured DMEM with 10% FBS and 1% antibiotics. The levels of IL-8 and MMP-3 mRNA were analyzed by real-time PCR. The levels of secreted IL-8 and MMP-3 protein expression were analyzed by ELISA and western blot analysis, respectively. Cell viabilities by drug were analyzed by MTT assay. Cell invasion and migration was detected by Boyden chamber assay.

Results: The level of IL-8 and MMP-3 mRNA and protein expression significantly increased by IL-1β treatment in both Hs578T cells and MDA-MB231 cells. In addition, IL-1β-induced cell migration and invasion also increased in Hs578T and MDA-MB231 cells. On the other hand, the levels of basal and IL-1β-induced IL-8 and MMP-3 expression were decreased by zerumbone.

Conclusion: IL-1β induces the migration and invasion of breast cancer cells through IL-8 and MMP-3 expression. These effects are significantly suppressed by zerumbone. Therefore, we suggest that zerumbone may act as a useful therapeutic agent for treatment of triple negative breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-19.

Abstract P5-09-17: Prognostic significance of progesterone receptor in hormonal receptor-positive breast cancer: Association with endocrine resistance

Background: Endocrine therapy has dramatic improvements of prognosis in patients with hormonal receptor positive breast cancer. However, long-term follow up shows that endocrine resistance is still major clinical concern. Although the value of estrogen receptor (ER) level can predict response to endocrine treatment in hormonal receptor positive breast cancers, few markers are available that can predict response to endocrine treatment. We attempted to identify molecular markers, especially progesterone receptor (PR), associated with endocrine failure in breast cancer.

Methods: We reviewed the medical records of 2513 breast cancer patients who underwent breast surgery and endocrine therapy at Samsung Medical Center between March 2007 and July 2011. Patients were compared according to ER and PR expression and to assess the clinical and biological features of ER+positive/PR-negative breast cancers to understand how PR might be a useful marker of these activities. ER and PR expression accessed using Allred score, the ‘positive” was defined that total score is larger than 2.

Results PR negative tumors were found more frequently in postmenopausal women (post- 11.2% vs. pre- 2.5%, P < 0.001) and PR negative tumors were significantly associated with higher grade, higher level of Ki 67 and more expression of EGFR and CK5/6. In Kaplan-Meier analysis and multivariate analysis, PR negativity was significantly poorer prognostic factor of DFS (HR 3.1, 95% CI 1.2-8.2, P = 0.021) and OS (HR 89.8, 95% CI 3.4-2352.3, P = 0.007). Stratified by the menopausal status, there was not shown significant difference of survival between the PR+ and PR- tumor in postmenopausal women (DFS, HR 2.1, 95% CI 0.4-10.8, P = 0.381; OS, HR 10.6, 95% CI 0.6-171.4, P = 0.096). However, PR negative tumors showed an association with poor outcome in premenopausal women (DFS, HR 7.2, 95% CI 2.5-20.6, P <0.001; OS, HR 24.6, 95% CI 2.2-275.6, P = 0.009).

Conclusion: In HR positive breast cancers, PR negative tumors were found more frequently in elderly, postmenopausal women. However, PR negative tumors are shown more aggressive and poorer survival than PR positive tumors despite of endocrine therapy, especially in premenopausal women.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-17.

Abstract P2-18-04: No further axillary dissection in sentinel lymph node-negative breast cancer after neoadjuvant chemotherapy in patients with initial cytologically-proven axillary node metastasis

Background

In patients with fine needle aspiration (FNA)-proven axillary lymph node metastasis at diagnosis (cN+), the current standard surgical procedure is axillary lymph node dissection (ALND) at definitive surgery after neoadjuvant chemotherapy (NAC). However, growing evidences suggest that SLNB after NAC is feasible and may demonstrate acceptable performance in selected patients. We performed sentinel lymph node biopsy in patients treated with cytologically-confirmed axillary lymph nodes metastases at presentation, who converted to a clinically negative axillary status after NAC (ycN0).

Patients and methods

We retrospectively evaluated 240 patients with invasive breast cancer with ultrasound-guided FNA-proven axillary nodal metastases at the time of diagnosis. All patients received NAC and underwent surgery at Samsung medical center between October 2007 and May 2013. Among these patients, 75 patients underwent SLNB. These patients converted to clinically node-negative disease (ycN0) after NAC on breast MRI or PET/CT scan. A combined detection technique was used with radioisotope and blue dye for the detection of SLN. Patients with negative SLN on frozen pathology and low clinical suspicion of metastasis during operation were not performed further ALND.

Results

The detection rate of SLNB was 93.3% (70/75), and median number of retrieved sentinel lymph nodes was 3.0 (range 1-8). False negative rate was 6.7% (1/15). Of these 75 patients, 35 (46.6%) patients had positive sentinel lymph nodes (ypN+) and underwent ALND. Thirty-five (46.6%) patients had tumor-free sentinel lymph nodes (ypN0sn) and 20 patients of them were followed without subsequent ALND. In these SLN-negative patients without further ALND, 9 patients were HER2-enriched subtypes and 9 patients, TNBC subtypes. Only two of them were Luminal B subtypes. The median follow-up period was 12.0 months (range 0-26 months) with 2 events; 1 regional recurrence in ipsilateral supraclavicular node and 1 systemic recurrence in brain on postoperative 7 months and 5 months, respectively. There has not occurred an ipsilateral axillary recurrence so far.

Conclusions Although the follow-up was not long enough to conclude, this study tried to demonstrate that SLNB after NAC was feasible and further ALND may not be necessary in patients with SLN-negative disease (ypN0sn).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-04.

Abstract P3-11-01: Matched-pair analysis of patients with male and female breast cancer

Purpose: Male breast cancer (MBC) is extremely rare, accounting for less than 1% of all malignancies in men and only 1% of all breast carcinomas. The treatment and surveillance guidelines on male breast cancers are less recognized. The aim of this study is to evaluate our single institution's experience with MBC over the past 15 years and to contrast differences between female and MBC.

Methods: MBC diagnosed from 1994 to 2010 at the Department of Surgery, Samsung Medical Center (Seoul, Korea) was retrospectively analyzed. Clinical data and tumor characteristics were examined. Each MBC was matched with female counterparts by 1:N varied matching ratio that showed accordance in seven variables (year of diagnosis, age, tumor stage, nodal stage, tumor grade, estrogen receptor(ER), progesterone receptor(PR)).

Results: 39 male/184 female matched-pairs were available for analysis. The median duration of follow-up was 3.8 years. The median age of MBC patients was 50 years and the median size of tumor was 2.0cm. The proportion of positivity of ER and PR status was 97.4% and 84.6%, respectively. Despite of higher positive rate of hormone receptor, the rate of hormone therapy in MBC patients was significant lower than female conterpart (p = 0.002). Men and women with breast cancer had similar disease-free survival (DFS) and disease-specific overall survival (DSS). Five MBC patients had a recurrence during follow up period and 4 of them were expired. The 10-years DFS was 73.1% in men and 80.5% in women (p = 0.348). The 10-years DSS was 74.1% in men and 87.1% in women, respectively (p = 0.207).

Conclusion: This study showed no disease free and overall survival differences between male and female breast cancer patients and revealed that gender is no predictor for survival in breast cancer. Male patients receive obviously less adjuvant treatment compared their female matched patients. It would be better to do more aggressive treatment in MBC to improve the survival outcome.

Successful Treatment of Pure Red Cell Aplasia with Rituximab in Patients after ABO-Compatible Allogeneic Hematopoietic Stem Cell Transplantation

Pure red cell aplasia (PRCA) following allogeneic hematopoietic stem cell transplantation (HSCT) has been mostly reported in situations involving major ABO incompatibility between donor and recipient. Conventional treatments such as plasma exchange, erythropoietin, and steroid are often unsatisfactory. Rituximab has been reported to be highly effective for PRCA following major ABO-incompatible allogeneic HSCT. A 49-year-old woman with PRCA following ABO-matched allogeneic HSCT for acute lymphoblastic leukemia, refractory to erythropoietin treatment, received 4 doses of rituximab 375 mg/m² weekly. After the 3rd dose of rituximab, she exhibited a striking rise in her reticulocyte count with an increase in her hemoglobin level. To our knowledge, this is the first case of PRCA following major ABO-compatible allogeneic HSCT resolving completely after rituximab treatment.

P5-14-02: Clinicopathologic and Prognostic Difference of Screen Detected Breast Cancer Compared with Symptomatic Breast Cancer

Background: Breast cancer screening program makes it possible to detect early cancer, thus to reduce breast cancer mortality. The authors studied clinicopathologic characteristics and prognosis of screen detected invasive breast cancer compared with symptomatic breast cancer. Furthermore, we compared the result according to molecular subtypes (luminal A, luminal B, Her2, triple negative), so intended to identify the role of screening in each subtypes. Material and Methods: From January 2002 to June 2008, 3141 patients who underwent operation for the treatment of invasive ductal carcinoma(NOS) at Samsung medical center were included. Among them, 1025 patient were screen detected, 2116 patient were symptomatic, out of screening over 2 years. We reviewed the medical records retrospectively.

Result: Screen detected breast cancer was associated with older patients, smaller tumor size, more hormone receptor- positive, less lymph node involvement, lower stage and reduced mortality compared with symptomatic breast cancer (P < .001). According to the molecular subtype, in luminal A subtype, the result shows better pathologic feature and also favorable overall and recur-free survial significantly.

P5-14-19: Ipsilateral Breast Tumor Recurrence Prediction with Web-Based Normogram in Korea

Purpose Ipsilateral Breast Tumor Recurrence(IBTR!) 2.0 is web-based tool which predict the ten years risk of local recurrence after breast conserving theraphy. This tool integrates seven prognostic factors (patient age, margin status, lymphovascular invasion, tumor size, tumor grade, use of chemotherapy and hormonal therapy) for local recurrence with or without radiation theraphy. To validate IBTR! 2.0 for Korean breast cancer patients, Samsung Medical Center database was used between 1994 and 2001.

Methods The IBTR! 2.0 nomogram was tested against 358 patients who underwent breast conserving surgery with radiation theraphy from Samsung Medical Center between 1994 and 2001. The individual dadabase which was entered into IBTR! 2.0 computer model generate predictive local recurrence rate. The mean predicted and observed 10-year estimates were compared for the entire cohort and for four groups predefined by nomogram-predicted risks: group 1: less than 3%; group 2: 3% to 5%; group 3: 5% to 10%; and group 4: more than 10%.

Results IBTR! version 2.0 predicted an overall 10-year IBTR estimate of 5.5% (95% CI, 5.2 to 5.9), while the observed estimate was 7.69% (20 IBTR cases in 358 patients, 95% CI, 1.6 to 9.3; P=0.59).

The predicted and observed IBTR estimates were: group 1 ( 2 cases in 67 patients): 2.3% versus 2.9%, P=0.53; group 2 (2 cases in 124 patients)): 3.9% versus 4.1%, P=0.18; group 3 (14 cases in 139 patinets): 7.3% versus 4.8%, P=0.13; and group 4 (2 cases in 28 patients): 12.15% versus 7.1%, P=0.61.

Conclusion IBTR! 2.0 is acceptable nomogram for predicting 10 years local recurrence using Samsung medical Center database. This nomogram showed overestimation in group 3, 4, however did not showed statistical differences. This nomogram may assist patient counseling and medical decision making, but prior to using whole Korean patients, this model requires validation with multiple Korean sources.

References

1. Fisher, B., et al., Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. N Engl J Med, 2002. 347 (16): p. 1233–41.

2. Liljegren, G., et al., 10-Year results after sector resection with or without postoperative radiotherapy for stage I breast cancer: a randomized trial. J Clin Oncol, 1999. 17 (8): p. 2326–33.

3. Anderson, S.J., et al., Prognosis after ipsilateral breast tumor recurrence and locoregional recurrences in patients treated by breast-conserving therapy in five National Surgical Adjuvant Breast and Bowel Project protocols of node-negative breast cancer. J Clin Oncol, 2009. 27 (15): p. 2466–73.

4. Sanghani, M., et al., Predicting the Risk of Local Recurrence in Patients With Breast Cancer. American Journal of Clinical Oncology, 2007. 30 (5): p. 473–480.

5. Sanghani, M., et al., Validation of a Web-Based Predictive Nomogram for Ipsilateral Breast Tumor Recurrence After Breast Conserving Therapy. Journal of Clinical Oncology, 2010. 28 (5): p. 718–722.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-19.

Fludarabine-containing chemotherapy for patients with previously untreated low-grade non-Hodgkin's lymphoma

BACKGROUND

The clinical efficacy and safety of fludarabine combination chemotherapy was investigated for the treatment of previously untreated patients with low-grade (NHL).

METHODS

Twenty-five patients who were newly diagnosed as low-grade NHL were treated with fludarabine combination chemotherapy. Fludarabine combination regimens consisted of fludarabine, mitoxantrone and dexamethasone or fludarabine, cyclophosphamide and mitoxantrone with or without rituximab and repeated every 4 weeks.

RESULTS

The median age was 60 years (range, 35-77 years), with 13 of 25 patients (52%) ≥60 years of age. Seven of 25 patients (28%) with an intermediate risk follicular lymphoma international prognostic index (FLIPI) and 9 of 25 patients (36%) with a high risk FLIPI were enrolled in this study. The delivered median number of chemotherapy was six (range, 2-9 cycles). The overall response rate with fludarabine-based treatment was 88%, including 52% complete remission and 36% partial remission. During the median follow-up of 19 months, the estimated 2-year event-free survival was 63±10% (95% CI, 43-83) and the 2-year overall survival was 78±9% (95% CI, 60-96). Fludarabine combination chemotherapy was frequently associated with grade 3 or 4 neutropenia in 84% patients. However, neutropenic infection was observed in only one (4%) patient. Four patients (16%) showed grade 3 or more non-hematologic toxicities, such as acute coronary syndrome, intracranial hemorrhage, anaphylaxis and gastric cancer.

CONCLUSION

Fludarabine-combination treatment was a highly active regimen with well toleration in untreated low-grade NHL.

A Case of Disseminated and Fulminant Plasmacytomas That Developed during Bortezomib Treatment

Multiple myeloma is an incurable and slow growing plasma cell neoplasm. The introduction of new drugs has increased the number of treatment options. Bortezomib, the first-in-class proteasome inhibitor, has been shown to have a significant antitumor activity in the treatment of relapse/refractory patients with multiple myeloma. Additionally, plasmacytomas have shown significant response to bortezomib. In this case report, we describe a patient who developed disseminated and fulminant extramedullary plasmacytomas during combination chemotherapy treatment with bortezomib within a short period, after having shown clinical improvement.

Prognostic significance of interim ¹⁸F-FDG PET/CT after three or four cycles of R-CHOP chemotherapy in the treatment of diffuse large B-cell lymphoma

PURPOSE

(18)F-fluoro-2-dexoy-D-glucose-positron emission tomography (FDG-PET)/computerised tomography (CT) has been used for staging and monitoring responses to treatment in patients with diffuse large B cell lymphoma (DLBCL). The sequential interim PET/CT was prospectively investigated to determine whether it provided additional prognostic information and could be a positive predictable value within patients with the same international prognostic index (IPI) after the use of rituximab in DLBCL.

METHODS

One hundred and sixty-one patients with newly diagnosed DLBCL were enroled; the assessment of the PET/CT was performed at the time of diagnosis and mid-treatment of rituxibmab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP).

RESULTS

Sixty-seven patients (41.6%) presented with advanced stage disease and 27 (16.8%) had bulky lesions. Forty-three patients (26.7%) continued to have positive metabolic uptakes with a significantly high relapse rate (62.8%) compared to the patients with a negative interim PET/CT (12.1%) (P<0.01). After a median follow-up of 30.8months, the positivity of interim PET/CT was found to be a prognostic factor for both overall survival (OS) and progression-free survival (PFS), with a hazard ratio of 4.07 (2.62-6.32) and 5.46 (3.49-8.52), respectively. In the low-risk IPI group, the 3-year OS and PFS rates were significantly different in the patients with positive (53.3% and 52.5%) and negative (93.8% and 88.3%) interim PET/CT, respectively (P<0.01). These significant prognostic differences of interim PET/CT responses were consistent with the results of the patients with high-risk IPI group (P<0.01).

CONCLUSIONS

Interim PET/CT scanning had a significant predictive value for disease progression and survival of DLBCL in post-rituximab treatment; it might be the single most important determinant of clinical outcome in patients with the same IPI risk.

Abstract P3-10-25: The Prognosis of Metaplastic Breast Cancer Patients Compare to Triple-Negative Breast Cancer Patients

Background: Metaplastic breeast cancer (MBC) is a rare, heterogenous cancer characterized by admixture of adenocarcinoma with metaplastic elements, low hormone receptor expression and poor outcome. This study was planned to assess the clinicopathological chacteristics and immunohistochemical findings of MBC compared to invasive ductal carcinoma (IDC) including the triple-negative subtype (TN-IDC). Material and Methods: We retrospectively reviewed the medical records of 47 MBC and 1,346 IDC patients. Two hundred eighteen TN-IDC patients were included in the 1,346 IDC patients. Between 2005 and 2009, these patients were undergone surgical treatment at the Samsung Medical Center. Patients were reviewed clinicopathologic factors, immunohistochemistry of biologic factors such as ER, PR, HER-2, p53, Ki67, cytokeratine (CK) 5/6, epidermal growth factor receptor (EGFR), and treatment modalities (type of operation, use of chemotherapy, radiotherapy and hormone therapy). Result: The MBC patients presented with a larger tumor size (&gt;T1, 66.0% vs. 44.3.%, P = 0.008), lower lymph node involvement (N0, 73.3% vs. 55.6%, P = 0.03), higher histologic (HG) and nuclear grade (NG) (HG3, 70.0% vs. 41.5%, P = 0.001; NG3,82.6% vs. 46.9%, P &lt; 0.001), fewer estrogen receptor (ER), progesterone receptor (PR) and HER2 positivity (ER+, 4.3% vs. 69.2%, P &lt; 0.001; PR+, 6.4% vs. 63.5%, P &lt; 0.001; HER2+, 0% vs. 27.6%, P &lt; 0.001), higher p53, CK5/6 and EGFR expression (p53+, 63.8% vs.38.8%, P &lt; 0.001; CK5/6+, 71.9% vs.21.5%, P &lt; 0.001; EGFR+, 93.9% vs.21.6%, P &lt;0.001) and more TN subtypes (93.6% vs. 16.2%, P &lt; 0.001) compared to the IDC group. There was no significant difference in clinicopathological characteristics with MBC and TN-IDC except EGFR over expression (EGFR+, 93.9% vs.69.0%, P = 0.017). In follow-up duration (median 30 months, range 2-56 months), seven (14.9%) MBC patients and 98 (7.2%) IDC patients recurred. The 3-year disease-free survival (DFS) rate was 78.1% in the MBC group and 91.1% in IDC group (P &lt;0.001). The 3-year DFS rate was not significantly difference between MBC group and TN-IDC group (78.1% vs. 84.9%, P = 0.114). However, in patients with lymph node metastasis who underwent adjuvant chemotherapy, the 3-year DFS rate was 44.4% in MBC group and 72.5% in TN-IDC group (P = 0.025).

Discussion: In our result, MBC show poorer clinical outcome than IDC. It is not shown significant difference between MBC and TN-IDC. However, MBC patients with nodal metastasis have poorer prognosis than TN-IDC patients with metastasis despite adjuvant chemotherapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-25.

Pomegranate (Punica granatum) seed linolenic acid isomers: concentration-dependent modulation of estrogen receptor activity

Pomegranate (Punica granatum) seed linolenic acid isomers were evaluated as selective estrogen receptor modulators (SERMs) in vitro. Punicic acid (PA) inhibited (IC(50)) estrogen receptor (ER) alpha at 7.2 microM, ERbeta at 8.8 microM; alpha-eleostearic acid (AEA) inhibited ERalpha/ERbeta at 6.5/7.8 microM. PA (not AEA) agonized ERalpha/ERbeta (EC(50)) at 1.8/2 microM, antagonizing at 101/80 microM. AEA antagonized ERalpha/ERbeta at 150/140 microM. PA and AEA induced ERalpha and ERbeta mRNA expression in MCF-7, but not in MDA-MB-231. Overall, the results show PA and AEA are SERMs.

Distinct locomotive patterns of granulocytes, monocytes and lymphocytes in a stable concentration gradient of chemokines

The pattern of leukocyte locomotion can be changed in many pathological situations, but its accurate analysis is difficult because of technological limitation. In the present study, by using a newly developed time-lapse videomicroscopic technique, we have analyzed the locomotive patterns of leukocytes in a stable concentration gradient of chemokines. Granulocytes, monocytes, and lymphocytes were purified from adult human peripheral blood. Locomotive behavior of the leukocytes was analyzed by an optical assay using a microchannel producing a stable concentration gradient of chemokines. Videomicroscopic analysis showed distinct locomotive patterns of granulocytes, monocytes, and lymphocytes. Granulocytes were intrinsically motile, vigorously moving in random direction without any chemokine stimulation. Upon stimulation with CXCL8/IL-8, the speed of migration was increased from 13.3 +/- 2.8 to 19.4 +/- 2.5 microm/min (P = 0.002, n = 100) and they moved toward the chemokine, although many cells still wandered very much. Stimulation with CCL5/RANTES or CXCL12/SDF-1alpha induced similar changes in locomotive pattern. On the other hand, most lymphocytes did not polarize or move spontaneously without chemokine stimulation. Stimulation with CXCL12 induced directional migration in 37% of the lymphocytes at a speed of 9.6 +/- 1.6 microm/min (n = 100). The movement pattern of monocytes was similar to that of granulocytes in that they tend to become polarized and move spontaneously, but they moved at a very slow speed ranging from 3.9 to 4.2 microm/min even with chemokine stimulation. The new optical assay may be useful for many diagnostic as well as basic studies.

Portable microscopic cell counter for the determination of residual leucocytes in blood components

BACKGROUND AND OBJECTIVES

The accurate determination of residual white blood cell (WBC) in blood components is of considerable clinical importance, and a variety of methods have been devised for the counting of low levels of residual WBC. In this study, we evaluated the performance of microscopic cell counter with microchannel plastic chip (C-reader) with regard to its ability to quantify WBC in WBC-reduced red cell concentrates.

MATERIALS AND METHODS

In order to quantify residual WBC with the microscopic cell counter, WBC-reduced red cell concentrate was stained using propidium iodide. Three studies were performed: linearity, precision and correlation compared to those of manual Nageotte chamber counting and automatic flow cytometric methods.

RESULTS

Dilution experiments, conducted over a range of 0.7-712 WBC/microl, showed a linearity of r(2) > 0.999, with coefficient of variation values of < or = 15.6% and accuracy of 93.8% over all tested ranges. In comparison with the Nageotte chamber counting and flow cytometric methods, the correlation coefficients were r(2) > 0.995. The detection limit of this method was 0.24 WBC/microl. Total analysis time per sample was approximately 5 min.

CONCLUSION

The microscopic cell counter for residual WBC counting was determined to be efficient at the level of currently defined standards, with acceptable precision and accuracy. This method may prove useful for the quality assurance and control of WBC-depleted blood products.

Y+ and y+ L arginine transporters in neuronal cells expressing tyrosine hydroxylase

Arginine is a semi-essential amino acid that serves as sole substrate for enzymes involved in diverse cell processes including redox balance via nitric oxide synthase (NOS) and cell proliferation via arginase. Neurons that express nNOS require intracellular arginine to generate nitric oxide (NO). Using a TH+ neuronal cell line (CAD cells), we show that neuronal NO production is largely dependent on extracellular arginine. Although a small intracellular pool exists in CAD cells, the lack of mRNA for argininosuccinate synthase (AS), a rate limiting enzyme for arginine recycling, suggests that intracellular pools are not re-supplied by this mechanism in this sub-class of neurons. Rather, arginine is taken up from the extracellular media by two primary transport systems, the y+ and the y+ L systems. The expression of CAT1, CAT3, y+ LAT1 and y+ LAT2 mRNAs supports the presence of each system. CAD cell arginine transport is depressed by increased extracellular K+ levels and demonstrates that variations in membrane potential control neuronal arginine uptake. Short term exposure to the oxidizing agents, rotenone and Angeli's salt, but not FeSO4, increases arginine transport. The regulation of arginine uptake by physiological factors suggests that arginine supply adapts in a moment-to-moment fashion to the changing needs of the neuron.

Disrupted spermine homeostasis: a novel mechanism in polyglutamine-mediated aggregation and cell death

Our data suggest a novel mechanism whereby pathological-length polyglutamine (polyQ) proteins promote the spermine synthetic pathway, increasing polyQ-aggregation and cell death. As detected in a cell-free turbidity assay, spermine promotes aggregation of thio-polyQ62 in a dose-dependent manner. Using a stable neuronal cell line expressing pathological-length [polyQ57-yellow fluorescent protein (YFP) (Q57)] or non-pathological-length [polyQ19-YFP (Q19)] polyglutamine protein, we show that multiple steps in the production of polyamines are affected in Q57 cells, suggesting dysfunctional spermine homeostasis. As the building block for spermine synthesis, arginine transport is significantly increased in neuronal cell lines stably expressing Q57. Q57 lines displayed upregulated basal and inducible arginase I activities that were not seen in polyQ19-YFP lines. Normal induction of spermidine/spermine N-acetyltransferase in Q19 lines regulating back-conversion of spermine, thereby reducing spermine levels, however, was not observed in Q57 lines. Pharmacological activation of ornithine decarboxylase (ODC), a key enzyme of the polyamine synthetic pathway, increased cellular aggregates and increased cell death in Q57 cells not observed in Q19 cells. Inhibition of ODC by difluoromethylornithine prevented basal and induced cell death in Q57 cells, demonstrating a central role for polyamines in this process.

Phorbol ester stimulates the nonhypoxic induction of a novel hypoxia-inducible factor 1alpha isoform: implications for tumor promotion

Hypoxia-inducible factor-1 (HIF-1), which is present at higher levels in human tumors, plays important roles in tumor promotion. It is composed of HIF-1alpha and HIF-1beta subunits and its activity depends on the amount of HIF-1alpha, which is tightly controlled by cellular oxygen tension. In addition to hypoxia, various nonhypoxic stimuli can stabilize HIF-1alpha in tumor cells, implying that both hypoxic and nonhypoxic stimuli contribute to the overexpression of HIF-1alpha in tumors. On the other hand, phorbol esters such as phorbol-12-myristate-13-acetate (PMA) are known to be potent tumor promoters. Here, we identified a novel HIF-1alpha isoform, which is regulated primarily by PMA. The variant mRNA lacks exon 11 and produces a 785-amino acid isoform (HIF-1alpha(785)) without altering the reading frame and therefore the COOH-terminal transcriptional activity. HIF-1alpha(785) is induced markedly by PMA and heat shock, the latter of which is also known to induce HIF-1alpha. HIF-1alpha(785) escapes from lysine acetylation because of the loss of Lys(532) and was stabilized under normoxic conditions. Its expression was blocked by reducing agents and by a mitogen-activated protein/extracellular signal-regulated kinase-1 inhibitor and enhanced by hydrogen peroxide. In addition, HIF-1alpha(785) overexpression strikingly enhanced tumor growth in vivo. These results suggest that HIF-1alpha(785) is induced by PMA under normoxic conditions via a redox-dependent mitogen-activated protein/extracellular signal-regulated kinase-1 pathway and that it plays an important role in tumor promotion.

The effect of phenyl substituents on the release rates of esterase-sensitive coumarin-based prodrugs

A coumarin-based prodrug system has been recently developed in our laboratory for the preparation of esterase-sensitive prodrugs of amines, peptides, and peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. In certain cases, the release can be undesirably slow for drugs that are secondary amines with relatively high pKa's. Aimed at finding ways to manipulate the release rates to suit the need of different drugs, we have examined the effect of the phenyl ring substitutions on the release kinetics of such prodrugs and found that appropriately positioned alkyl substituents on the phenyl ring could help to facilitate the release by as much as 16-fold. Therefore, introduction of alkyl substituents on the phenyl ring should allow us to manipulate the release rates and, therefore, time profiles for different drugs.

Comparison of muscle oxygen consumption measured by near infrared continuous wave spectroscopy during supramaximal and intermittent pedalling exercise

The two purposes of the present study were 1) to determine the oxygen consumption in working skeletal muscle from the oxygenation measured by near-infrared continuous-wave spectroscopy (NIRcws) with the arterial occlusion method during the resting condition, INT(VT), and INT(MAX) and 2) to examine whether the decline rate of oxygenation is related to maximal oxygen uptake. Eight healthy males (aged 19.8 +/- 0.4 yr, height 166.9 +/- 17.4 cm, weight 62.1 +/- 2.5 kg, and maximal oxygen uptake [VO2max] 55.9 +/- 1.9 ml/kg x min(-1)) took part in this study. The oxygenation was measured by NIRcws during the Wingate anaerobic test (WAnT) and two intermittent pedalling exercises of VT (INT(VT)) and maximal (INT(MAX)) work intensity. The decline rates of oxygenation obtained during the resting condition, INT(VT), and INT(MAX) with arterial occlusion were 0.43 +/- 0.05%/sec, 4.94 +/- 0.31%/sec, and 8.16 +/- 0.38%/sec, respectively, and that during the WAnT without arterial occlusion was 8.73 +/- 0.49%/sec. The decline rate of oxygenation during the WAnTwas significantly (p < 0.0001) related to maximal oxygen uptake (VO2max). These findings indicate that O2 is utilized from the early phase, even during a supramaximal pedalling exercise, and that the oxidative metabolic capacity may be a factor contributing to supramaximal exercises. Therefore the arterial occlusion method with NIRcws is suitable for the evaluation of the muscle O2 consumption during exercise noninvasively.