Contribution of the human cytochrome P450 2C subfamily to the metabolism of and the interactions with endogenous compounds including steroid hormones

The objectives of this study were as follows: 1) to compare the metabolic activities of endogenous compounds and their effects on dopamine formation and hydroxylation of steroid hormones, mediated by human cytochrome P450 (CYP), including CYP2C9.1 and CYP2C19, as well as the variants CYP2C9.2 (Arg144Cys) and CYP2C9.3 (Ile359Leu); and 2) to assess the effects of steroid hormones on the activities of CYP2C9.1, CYP2C9.2, and CYP2C19 to estimate the contribution of the CYP2C subfamily to metabolism and drug-drug interactions of endogenous compounds. Dopamine formation from p -tyramine and 6β- and 21- (for progesterone) hydroxylation of testosterone, cortisol, and progesterone by CYP2C9 variants, CYP2C19, CYP2D6, and CYP3A4 were determined using HPLC. The effects of steroid hormones such as testosterone, cortisol, and progesterone on tolbutamide methyl hydroxylation mediated by CYP2C subfamily members were investigated. Only CYP2D6 catalyzed dopamine formation. The 6β-hydroxylation activities of testosterone, cortisol, and progesterone catalyzed by CYP2C9 variants and CYP2D6 were less than 5% of those by CYP3A4. Although cortisol did not inhibit tolbutamide methyl hydroxylation catalyzed by CYP2C9.1, CYP2C9.2, or CYP2C19 and testosterone did not inhibit CYP2C19 activity, the reactions catalyzed by CY2C9.1 and CYP2C9.2 were inhibited by testosterone. The inhibition of progesterone by CYP2C19 was stronger than that by CYP2C9.1 and CYP2C9.2. CYP2C9.1 and CYP2C19 noncompetitively and competitively inhibited tolbutamide methyl hydroxylation with inhibition constants of 43.2 μM and 1.03 μM, respectively. Clinical interactions among endogenous compounds would vary within the CYP2C subfamily, although the contribution of the CYP2C subfamily may be of minor importance for dopamine formation and the detoxification (6β-hydroxylation) of endogenous steroid hormones.

Clinical impact of triglyceride deposit cardiomyovasculopathy, coronary atherosclerosis with triglyceride deposition, on vascular failure after drug-eluting stent implantation

Background

Triglyceride deposit cardiomyovasculopathy (TGCV) is a novel cardiovascular disorder, encoded as orphan disease in Europe in 2019, characterized by excessive accumulation of triglyceride in vascular smooth muscle cells, leading to coronary artery disease (CAD). However, there is no data about impact of TGCV on vascular failure after coronary stent implantation.

Purpose

To assess impact of TGCV on the outcome following coronary stent implantation in CAD patients with diabetes mellitus (DM) as Study 1, and chronic hemodialysis as Study 2.

Methods

This is multicenter retrospective estimation consisting of two studies.

Study 1) Among 526 consecutive patients suspected of having CAD who underwent coronary angiography (CAG) and iodine-123-β-methyliodophenyl-pentadecanoic acid (BMIPP) scintigraphy, a tracer for the diagnosis of TGCV, data from 81 patients with DM were analyzed.

The patients were divided into two groups; TGCV (n=7) or non-TGCV (n=74). All patients were implanted with a second-generation DES and underwent follow-up CAG. Binary restenosis (ISR), defined as angiographic luminal diameter >50% by quantitative coronary angiography, in-stent late loss were assessed in 15 stents of TGCV patients and 111 stents of non-TGCV patients.

Study 2) Similarly, among 88 chronic hemodialysis patients, ISR and in-stent late loss were assessed in 12 stents of 9 TGCV patients and 21 stents of 17 non-TGCV patients.

Results

Study 1) There were no significant differences in baseline characteristics between the two groups. In-stent late loss was greater in TGCV group than in non-TGCV group (0.91mm [0.27, 2.39] vs. 0.15mm [0.03, 0.35]; p<0.001), resulting in greater incidence of ISR in TGCV group than in non-TGCV group (46.7% vs. 9.0%; p<0.001). Multivariable logistic analysis revealed TGCV to be an independent predictor for vascular failure after DES implantation in patients with DM.

Study 2) Similarly, in-stent late loss and incidence of ISR were greater in TGCV group than in non-TGCV group (1.20±0.99mm vs. 0.50±0.70, p=0.02; 58.3% vs. 9.5%, p=0.002, respectively). TGCV was an independent predictor for vascular failure after DES implantation in chronic hemodialysis patients.

Conclusion

Apart from existing risk factors such as DM and hemodialysis, TGCV could contribute to a novel risk factor for vascular failure, even in the second-generation DES era.

Figure 1

Funding Acknowledgement

Type of funding source: None

Effect of therapeutic plasma exchange on phenytoin plasma concentration in patients receiving intravenous fosphenytoin therapy

We report for patients with encephalitis treated with plasma exchange (PE) and fosphenytoin. In patient 1, phenytoin levels decreased on the maintenance dose, and the phenytoin concentration was <10 μg/mL on day 12 of administration. In patient 2, the phenytoin levels was <10 μg/mL on day 4. Increasing the fosphenytoin dose pushed the phenytoin level into therapeutic range. There were no differences between the areas under the concentration-time curve of phenytoin with and without PE. We previously reported a decline in phenytoin levels after prolonged use of fosphenytoin. Therefore, dose adjustment of fosphenytoin in patients undergoing PE may be unnecessary.

Pyogenic spondylitis with acute course caused by Corynebacterium simulans

Corynebacterium simulans was first reported in 2000. Although it is a member of the normal skin flora, some cases of C. simulans infection have been reported. Other Corynebacterium spp. rarely cause chronic pyogenic spondylitis, and pyogenic spondylitis caused by C. simulans has not been reported at all. Here we report a case of acute pyogenic spondylitis due to C. simulans. A 78-year-old man with diabetes mellitus visited our hospital with a 3-day history of lower back pain and fever. Blood culture revealed C. simulans and magnetic resonance images of lumbar vertebrae showed pyogenic spondylitis. He recovered after treatment by vancomycin for 9 weeks and was discharged home. No recurrence has been observed for half a year. This is likely the first reported case of pyogenic spondylitis by C. simulans. In general, Corynebacterium spp. cause chronic pyogenic spondylitis, but this case showed an acute course.

P3638Triglyceride deposite cardiomyovasculopathy latency in population with coronary artery disease

Background

Triglyceride deposit cardiomyovasculopathy (TGCV) is a novel clinical concept found among Japanese cardiac transplant recipients in 2008 that the abnormal intracellular triglyceride (TG) metabolism results in the ectopic accumulation of TG in vascular smooth muscle cells and cardiomyocytes, leading to diffuse narrowing coronary artery disease (CAD) and heart failure. TGCV is estimated to affect almost forty to fifty-thousand people in Japan, but there is no real-world date about the prevalence or latency.

Purpose

To evaluate TGCV latency in population with CAD, especially requiring urgent coronary angiography as Study 1, and chronic hemodialysis as Study 2.

Methods

This is multicenter retrospective estimation consisting of two studies.

Study 1) From 2012 to 2017, consecutive 400 patients of unstable angina or acute myocardial infarction who underwent urgent coronary angiography (CAG) and following iodine-123-β-methyliodophenyl-pentadecanoic acid (BMIPP) scintigraphy, a tracer for the diagnosis of TGCV, were enrolled.

Study 2) From 2011 to 2017, 88 chronic hemodialysis patients who underwent planed CAG and BMIPP scintigraphy for detection of ischemic heart disease were enrolled.

TGCV was diagnosed based on the latest diagnostic criteria for TGCV. The criteria include two major items (2 points each: BMIPP scintigraphy Wash-Out Rare <10%, Diffuse narrowing coronary arteries) and two minor items (1 point each: Jordans' anomaly in peripheral blood smear, Diabetes). Four points or more and three points indicated definite and probable TGCV, respectively. Only Items other than Jordans' anomaly were available for the diagnosis of TGCV because of retrospective nature. We evaluated the latent rate of definite and probable TGCV.

Results

Study 1) Figure (left) demonstrates the result of Study 1. Definitive TGCV patients were 14 patients, accounting for 3.5% of total 400 patients, and probable TGCV patients were 39 patients, accounting for 9.8% of all. Total 53 definitive and probable TGCV patients accounted for 13.3% of all. Annual average latency were 3.6±1.7% as definitive, 10.0±5.5% as probable and 13.6±6.6% as definitive and probable TGCV, respectively.

Study 2) Figure (right) demonstrates the result of Study 2. Definitive TGCV patients were 17 patients, accounting for 19.3% of total 88 hemodialysis patients, and probable TGCV patients were 22 patients, accounting for 25.0% of all. Total 39 definitive and probable TGCV patients accounted for 44.3% of all. Annual average latency of definitive TGCV was 19.3±13.4%. Of the 17 definitive TGCV patients, 9 patients were hemodialysis patients with diabetes.

Figure 1

Conclusions

TGCV might be latent with a probability of 3.6±1.7% per year in patients with unstable angina or acute myocardial infarction, and with a probability of 19.3±13.4% per year in chronic hemodialysis patients suspected of ischemic heart disease.

P2688A novel risk factor of stent restenosis after drug-eluting stent implantation; Involvement of triglyceride deposit cardiomyovasculopathy, coronary atherosclerosis with triglyceride deposition

Background

Triglyceride deposit cardiomyovasculopathy (TGCV) is a novel disease concept characterized by the excessive accumulation of triglyceride in cardiomyocytes and vascular smooth muscle cells, leading to coronary artery disease (CAD), heart failure, and arrhythmia. However, it is rarely known whether TGCV contributes to the increased risk of vascular failure after drug eluting stent (DES) implantation.

Purpose

The aim of this study was to evaluate vascular failure after 2nd generation DES implantation in patients with TGCV.

Methods

Among 637 consecutive patients suspected of having CAD who underwent both coronary angiography and iodine-123-β-methyliodophenyl-pentadecanoic acid (BMIPP) scintigraphy between 2010 and 2018, we analyzed the data from 92 patients who met the inclusion criteria (shown in Table and Figure). Ninety-two patients were allocated to the presence (TGCV group, 11 patients) or absence (control group, 81 patients) of TGCV. All of 92 patients were implanted 2nd generation DES and underwent planned follow up coronary angiography. Control patients were diagnosed of diabetes mellitus. Binary restenosis (ISR), defined as angiographic luminal diameter ≥50% by quantitative coronary angiography, target lesion revascularization (TLR), In-stent late loss and restenosis morphology were assessed in 23 stents of TGCV group and 120 stents of control group.

Results

There were no significant differences in baseline characteristics between the two groups except for the prevalence of hypertension. In-stent late loss was greater in TGCV than in control (0.45 (−0.04 to 3.33) vs. 0.15 (−0.18 to 2.75), p=0.ehz748.10067), resulting in greater incidence of ISR and TLR in TGCV than in control (34.8% vs. 10.0%, p=0.0017; 21.7% vs. 6.7%, p=0.021, respectively). On multivariable logistic regression analysis, TGCV was found to be a significant and independent predictor for ISR after 2nd generation DES implantation. Regarding restenosis morphology, diffuse and occlusive pattern of ISR, were more frequently observed in TGCV than control (87.5% and 33.3%, Fisher's exact test p=0.028).

Table 1.The 4th edition diagnostic criteria for TGCV Items Clinical findings 2 points I) BMIPP scintigraphy Wash-Out Rare <10% II) Diffuse narrowng coronary arteries 1 point III) Jordans anomaly in peripheral blood smear IV) Diabetes Decision 4 points or more → Definite TGCV

Figure 1

Conclusion

Patients with TGCV showed the greater incidence of vascular failure even after 2nd generation DES implantation, contributing to the novel risk factor for coronary intervention even in the 2nd DES era.

The cosmic ray energy spectrum measured with the new Tibet hybrid experiment

We have upgraded the new Tibet ASgamma experiment in China since 2014 to measure the chemical composition of cosmic rays around the knee. This hybrid experiment consist of an air-shower-core detector array (YAC-II) to detect high energy electromagnetic component, the Tibet air-shower array (Tibet-III) and a large underground water-Cherenkov muon-detector array (MD). We have carried out a detailed air-shower Monte Carlo (MC) simulation to study the performance of the hybrid detectors by using CORSIKA (version 7.5000), which includes EPOS-LHC, QGSJETII-04, SIBYLL2.1 and SIBYLL2.3 hadronic interaction models. The preliminary results of the interaction model checking above 50 TeV energy region are reported in this paper, and the primary proton and helium spectra in the energy range 50 TeV to 1015 eV was derived from YAC-I data and is smoothly connected with direct observation data at lower energies and also with our previously reported works at higher energies within statistical errors. The knee of the (P+He) spectra is located around 400 TeV. The interaction model dependence in deriving the primary (P+He) spectra is found to be small (less than 25% in absolute intensity, 10% in position of the knee), and the composition model dependence is less than 10% in absolute intensity.

Risk factors for decreased teicoplanin trough concentrations during initial dosing in critically ill patients

Aim of the study: Here, we investigated the risk factors for decreased teicoplanin plasma trough concentrations relative to the initial dosing in critically ill patients. Patients and methods: Data obtained from 80 eligible critically ill patients who received intravenous teicoplanin were retrospectively analyzed. Risk factors for decreases in teicoplanin trough concentrations 72 h after administration of teicoplanin of more than 30% relative to predicted concentrations based on initial dosing setting were identified by logistic regression analysis. Results: Although prediction trough concentration and total dose of two days no significant differences were seen between the variation group and the non-variation group, actual trough concentration was significantly different between two groups (19.9±5.6 μg/ml vs 10.3±2.2 μg/ml, p < 0.001). In multivariate analysis, serum albumin ≤ 2.2 mg/dl (odds ratio [OR] = 3.003, 95% CI 1.072-8.408; p = 0.036) and SOFA score ≥ 9 (OR = 3.498, 95% CI 1.171-10.450; p = 0.025) were significant risk factors for decreased teicoplanin plasma trough concentrations. Conclusion: In critically ill patients, high SOFA score and low serum albumin were risk factors for decreased teicoplanin plasma trough concentration during initial dosing.

Test of the hadronic interaction models SIBYLL2.3, EPOS-LHC and QGSJETII- 04 with Tibet EAS core data

A hybrid experiment has been started by the ASγ experiment at Yangbajing (4300m a.s.l.) in Tibet since May 2009, that consists of a high-energy air-shower-core array (YAC-I) and a high-density air-shower array (Tibet-III). In this paper, we report our results to check the hadronic interaction models SIBYLL2.3, SIBYLL2.1, EPOS-LHC and QGSJETII-04 in the multi-tens TeV energy region using YAC-I+Tibet-III experimental data from May 2009 through January 2010. The effective live time is calculated as 106.05 days. The results show that the description of transverse momentum, inelastic cross-section and inelasticity for the 4 hadronic interaction models is consistent with YAC-I experimental data within 15% systematic errors range in the forward region below 100 TeV. Among them, the EPOS-LHC model is the best hadronic interaction model. Furthermore, we find that the H4a composition model is the best one below the 100 TeV energy region.

On the Solar Cycle Variation of the Solar Diurnal Anisotropy of Multi-TeV Cosmic-ray Intensity Observed with the Tibet Air Shower Array

We analyze the temporal variation of the solar diurnal anisotropy of the multi-TeV cosmic-ray intensity observed with the Tibet air shower array from 2000 to 2009, covering the maximum and minimum of the 23rd solar cycle. We comfirm that a remarkable additional anisotropy component is superposed on the Compton-Getting anisotropy at 4.0 TeV, while its amplitude decreases at higher energy regions. In constrast to the additional anisotropy reported by the Matsushiro experiment at 0.6 TeV, we find the residual component measured by Tibet at multi-TeV energies is consistent with being stable, with a fairly constant amplitude of 0.041% ± 0.003% and a phase at around 07.17 ± 00.16 local solar time at 4.0 TeV. This suggests the additional anisotropy observed by the Tibet experiment could result from mechanisms unrelated to solar activities.

Translocator protein 18kDa antagonist ameliorates stress-induced stool abnormality and abdominal pain in rodent stress models

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by abdominal pain and abnormal bowel habits, both of which are exacerbated by psychological stress. The translocator protein 18kDa (TSPO) is a marker of reactive gliosis in a number of central nervous system (CNS) diseases and responsible for many cellular functions, including neurosteroidogenesis. Although it has been reported that psychological stress disturbs neurosteroids levels, the pathophysiological relevance of TSPO in IBS is poorly understood.

METHODS

We examined the effects of a TSPO antagonist, ONO-2952, on stress-induced stool abnormality and abdominal pain in rats, and on anxiety-related behavior induced by cholecystokinin.

KEY RESULTS

Oral administration of ONO-2952 attenuated stress-induced defecation and rectal hyperalgesia in rats with an efficacy equivalent to that of a 5-HT₃ receptor antagonist. In addition, ONO-2952 suppressed cholecystokinin-induced anxiety-like behavior with an efficacy equivalent to that of psychotropic drugs. On the other hand, ONO-2952 did not affect spontaneous defecation, gastrointestinal transit, visceral nociceptive threshold, and neurosteroid production in non-stressed rats even at a dose 10 times higher than its effective dose in the stress models.

CONCLUSIONS AND INFERENCES

These results suggest that TSPO antagonism results in antistress action, and that ONO-2952 is a promising candidate for IBS without side effects associated with current treatment.

Risk factors for the failure of treatment of Pseudomonas aeruginosa bacteremia in critically ill patients

Pseudomonas aeruginosa bacteremia is associated with high morbidity and mortality in critically ill patients. In this study, we assessed risk factors for clinical failure of first definitive therapy for P. aeruginosa bacteremia in critically ill patients. All patients with P. aeruginosa bacteremia who entered the intensive care unit in Gifu University Hospital from January 2006 to December 2015 were retrospectively identified from electronic records. Risk factors associated with clinical failure of the first definitive therapy for P. aeruginosa bacteremia were analyzed by logistic regression analysis. A total of 28 patients were enrolled in the analysis. On multivariate analysis, severe burns (odds ratio [OR] = 70.9, 95% CI 2.9-1720.3; p = 0.009) and SOFA score ≥ 10 (OR = 28.5, 95% CI 1.1-754.3; p = 0.045) were significant factors in the clinical failure of first definitive therapy for P. aeruginosa bacteremia. The clinical success rate of first definitive therapy was significantly reduced in patients with these risk factors compared with those without them (p < 0.001). Severe burns and a SOFA score (≥ 10) were significant risk factors associated with the clinical failure of first definitive therapy for P. aeruginosa bacteremia in critically ill patients. We therefore recommend the use of therapeutic drug monitoring to optimize antibiotic dosing in these critically ill patients.

Exploration of Vogt-Koyanagi-Harada Syndrome by Infrared Choroidal Angiography with Indocyanine Green

The choroid affected by the Vogt-Koyanagi-Harada syndrome (VKH) has seldom been explored by indocyanine green choroidal angiography. Five patients with definite diagnosis of VKH underwent this investigation. The first case had the most marked leakage, very similar to that on fluorescein angiography. The right eye of case 2 showed fewer leakage points on ICG than on fluorescein angiography, compared with case 1. The left eye of case 2 did not show any leakage. Cases 3, 4 and 5 yielded segmental hyperfluorescence, distant from the posterior pole, which could not be identified by fluorescein angiography. This might indicate segmental choroiditis. There were two types of hypofluorescent lesions; all the cases except case 2 showed early hypofluorescence. Hypofluorescent areas corresponding to overlying retinal detachment were seen in the right eye of case 4. Multiple spots, late hypofluorescence, about 200 to 500 um in size appeared throughout the posterior pole in four eyes out of ten. In conclusion, indocyanine green choroidal angiography provides a wider variety of pictures than fluorescein angiography.

Abstract P4-03-12: Effects of PI3K inhibitors on endocrine-resistant cell lines and differences in the characteristics of ER positive breast cancer cells after acquired resistance to the inhibitors

Background

Mutations in phosphatidylinositol 3-kinase (PI3K), which encodes the catalytic subunit of PI3Kα, is one of the most frequent genomic alterations and is found in about 40% of estrogen receptor (ER)-positive, HER2 negative breast cancers. PIK3CA mutations promote the growth and proliferation of cancers via activation of the PI3K/mammalian target of rapamycin pathway and can mediate resistance to endocrine therapies in breast cancer. Although several clinical trials for PI3K inhibitors (PI3Kis) in ER-positive metastatic breast cancers are ongoing, the effects of PI3Kis on endocrine-resistant breast cancers with various characteristics and definitive biomarkers of PI3Kis are unclear. Using endocrine-resistant cells established in our laboratory, we evaluated the efficacy of PI3Ki in these cell lines and identified the characteristics associated with acquired resistance to PI3Kis in endocrine-resistant cells.

Results

Long-term estrogen deprivation-resistant (EDR) cell lines and fulvestrant-resistant cell lines (MFR and TFR) were established from MCF-7 and T-47D cells in our previous studies. These cell lines showed different ER expression levels, including high expression (EDR-1), low expression (EDR-2, -3), or no expression (MFR, TFR); all of these cell lines had the same PIK3CA mutations as the parental cell lines. The pan-class1 PI3Ki buparlisib (BKM120) and α-specific PI3K inhibitor alpelisib (BYL719) inhibited the proliferation of endocrine-resistant cell lines when compared with their parental cells. Among endocrine-resistant cells, MFR cells were dramatically inhibited by PI3Kis. Colony formation assays indicated that MFR cells were more sensitive to PI3Kis than other cells lines. Next, we established PI3Ki- and everolimus-resistant cell lines from EDR-1, EDR-2, and MFR cells using BKM120, BYL719, and everolimus. Analysis of the time required to generate resistant cells showed that MFR cells required twice as long to acquire resistance compared with EDR cells. Furthermore, the time required to acquire resistance to BYL719 was shorter than that for BKM120. BYL719-resistant (BYL-R) cells were effectively inhibited by BKM120 to a degree similar to that of parental cells; however, BYL-R cells lost sensitivity to BYL719 and everolimus. Evelolimus-resistant (EVE-R) cells were also the same. In contrast, BKM120-resistant (BKM-R) cells showed less sensitivity to BKM120, BYL719, and everolimus. In other words, the pan-PI3Ki BKM120 was able to inhibit the growth of BYL-R and EVE-R cells, whereas BYL719 and everolimus were not able to inhibit BKM-R cells sufficiently. In addition, there were no changes in ER expression in EDR-1, EDR-2, and MFR cells exposed to PI3Kis for 1 h. Interestingly, ER expression on EDR-2 cells with acquired resistance to PI3Kis was increased compared with that in parental cells.

Conclusion

Our findings showed that PI3Kis exhibited remarkable efficacy in all types of EDR cells, particularly in fulvestrant-resistant cell lines. In PI3Ki- and everolimus-resistant cell lines, BKM120 and BYL719 showed different effects, and BYL719 and everolimus may exhibit cross-resistance. Furthermore, PI3Kis were likely to change the expression of ER.

Citation Format: Tokuda E, Komatsu T, Sasaki S, Tsuboi K, Nakamura M, Iida M, Niwa T, Saito M, Hayashi S-I. Effects of PI3K inhibitors on endocrine-resistant cell lines and differences in the characteristics of ER positive breast cancer cells after acquired resistance to the inhibitors [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 P4-03-12.

Abstract P6-04-02: CDK6 might be a key factor for efficacy of CDK4/6 inhibitor and the hormone sensitivity following acquired resistance

Background: CDK4/6 inhibitors have received FDA breakthrough therapy designation as 1st line treatment for advanced estrogen receptor positive breast cancer patients. However, the benefit offered by CDK4/6 inhibitors is individually different and furthermore acquired resistance to the drugs is monumental challenges. It is urgent need to search for the biomarker and understand the drug sensitivity and its alteration after acquired resistance.

Results: To identify the efficacy of CDK4/6 inhibitors, we assessed IC50 of ribociclib in several cell lines. Luminal cell lines (MCF-7, T-47D) exhibited lower ribociclib IC50 than HER-2 (SK-BR-3) and triple negative cell lines (MDA-MB-231, BT-20). Immunoblot analysis of Luminal cell lines showed extremely lower levels of CDK6 compared with others. CDK6-transfected MCF-7 by means of expression vector reduced the sensitivity equivalent to MDA-MB-231 not only to ribociclib but also to palbociclib and abemaciclib. Protein level of ERα in CDK6-transfected MCF-7 stayed unchanged and fulvestrant sensitivity was unaltered as well.

Subsequently, we detect the efficacy of ribociclib in hormone resistant cell lines. Estrogen deprivation-resistant (EDR) cells (EDR1:ER-positive, EDR2:ER-negative) and fulvestrant resistance (MFR) cells (loss of ER expression) established from MCF-7 maintained ribocilib sensitivity to the same degree with MCF-7. No marked difference in IC50 was observed between EDR1/2 and MFR, and CDK6 expressions were comparable to MCF-7. These results suggest that high level of CDK6 expression weaken the sensitivity to CDK4/6 inhibitors. The inhibitors would provide more effective benefits to tumors expressing lower level of CDK6 than the higher, independent of hormone sensitivity.

To understand the characteristics in acquired resistance, ribociclib resistant cell lines (RIBR1/2) were established from EDR1 by long-term culture with ribociclib. RIBR designed lower level of p21, p27 and ERα by immunoblot analysis. EDR1 were promoted cell growth by estrogen addition, while RIBR were not. Further, ER activity of RIBR was intensely decreased, and mRNA levels of the ER target genes, PgR and EGR3 were also decreased. Therefore, the responsiveness to tamoxifen and fulvestrant were lost. On the other hand, PI3K inhibitor and mTOR inhibitor suppressed cell growth to the same extent as EDR1, suggesting that RIBR were reduced ER dependence and remain reliant on PI3K/Akt/mTOR pathway.

Conclusion: The possibility of CDK6 as a biomarker is corroborated by the finding that low level of CDK6 expression is positively correlated with the efficacy of CDK4/6 inhibitor. Further ER dependence had decreased after acquired CDK4/6 inhibitor resistance whereas the dependence on PI3K/Akt/mTOR pathway still remain, indicating the inhibition of PI3K/Akt/mTOR pathway would be amenable to therapeutic target.

Citation Format: Iida M, Nakamura M, Tokuda E, Niwa T, Ishida T, Hayashi S-I. CDK6 might be a key factor for efficacy of CDK4/6 inhibitor and the hormone sensitivity following acquired resistance [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 P6-04-02.

Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

A simplified chart for determining the initial loading dose of teicoplanin in critically ill patients

AIM OF THE STUDY

A simplified chart to determine the initial loading dose of teicoplanin (TEIC chart) for achieving the target trough concentration was developed. The aim of the present study was to evaluate the usefulness of this chart in critically ill patients.

PATIENTS AND METHODS

The initial loading dose and maintenance dose to achieve a target trough concentration ≥10 μg/mL on day 4 was determined using the teicoplanin TDM software and presented in a TEIC chart. The dosage of teicoplanin, including the loading dose for the first 2 days and the maintenance dose thereafter, was selected from the chart (chart method, N = 41) or calculated using TDM software (software method, N = 39).

RESULTS

The performance rate of initial loading of teicoplanin increased from 83.0% to 100% after the TEIC chart was introduced (P = 0.016). The TEIC chart significantly reduced the time required for determining the initial loading dose compared with the use of software (1.9±0.6 min vs. 29.7±13.8 min, P < 0.001). No significant differences were observed in the rates of achieving a target level ≥10 μg/mL (P = 0.766).

CONCLUSION

The TEIC chart enables a simple, rapid, and reliable determination of teicoplanin dosage.

Evaluation of the pharmacokinetic parameters of standard oral antibiotics in a bioequivalence study of generic products

Pharmacokinetic parameters were summarized in clinical bioequivalence studies in Japan to confirm the validity for the use of parameters obtained from the clinical studies. Pharmacokinetic parameters, including maximum plasma/serum concentrations (Cmax), area under the plasma/serum drug concentration-time curve (AUC), time to achieve Cmax (Tmax), and half life (t1/2), of the standard products (original drugs) after oral administration of antimicrobials, including respiratory quinolones, cephalosporins, macrolides, and penicillin-based antibiotics were investigated by use of interview forms and/or package inserts from the generic products and the relationship among the pharmacokinetic parameters such as Cmax, AUC, Tmax, and t1/2 were estimated. In all the studies, the standard and generic products were administrated orally to healthy fasting subjects. Although there was more than a 1.5-fold difference in the Cmax and AUC0-24 h, but not in the Tmax and t1/2 values for levofloxacin tablets and cefacrol tablets, these parameters for other antibiotics were similar in various studies. The obtained results suggested that the parameters obtained from recent bioequivalence studies would be useful in identifying pharmacokinetic behavior of the original drugs, especially early time release; however, the pharmacokinetic results obtained from the recently conducted bioequivalence studies may be superior to those obtained from studies conducted in the past.

Quiet T1-Weighted Pointwise Encoding Time Reduction with Radial Acquisition for Assessing Myelination in the Pediatric Brain

BACKGROUND AND PURPOSE

T1-weighted pointwise encoding time reduction with radial acquisition (PETRA) sequences require limited gradient activity and allow quiet scanning. We aimed to assess the usefulness of PETRA in pediatric brain imaging.

MATERIALS AND METHODS

We included consecutive pediatric patients who underwent both MPRAGE and PETRA. The contrast-to-noise and contrast ratios between WM and GM were compared in the cerebellar WM, internal capsule, and corpus callosum. The degree of myelination was rated by using 4-point scales at each of these locations plus the subcortical WM in the anterior frontal, anterior temporal, and posterior occipital lobes. Two radiologists made all assessments, and the intra- and interrater agreement was calculated by using intraclass correlation coefficients. Acoustic noise on MPRAGE and PETRA was measured.

RESULTS

We included 56 patients 5 days to 14 years of age (mean age, 36.6 months) who underwent both MPRAGE and PETRA. The contrast-to-noise and contrast ratios for PETRA were significantly higher than those for MPRAGE (P < .05), excluding the signal ratio for cerebellar WM. Excellent intra- and interrater agreement were obtained for myelination at all locations except the cerebellar WM. The acoustic noise on PETRA (58.2 dB[A]) was much lower than that on MPRAGE (87.4 dB[A]).

CONCLUSIONS

PETRA generally showed better objective imaging quality without a difference in subjective image-quality evaluation and produced much less acoustic noise compared with MPRAGE. We conclude that PETRA can substitute for MPRAGE in pediatric brain imaging.

Early optimization of antimicrobial therapy improves clinical outcomes of patients administered agents targeting methicillin-resistant Staphylococcus aureus

WHAT IS KNOWN AND OBJECTIVE

Antimicrobial stewardship is required to ensure the appropriate use of antimicrobials. However, no reports have been published on clinical outcomes of implementation of antimicrobial stewardship in patients receiving pathogen-specific antibiotics.

METHOD

To evaluate the clinical outcomes of patients who received drugs, we conducted a single-centre, retrospective study of the effects of an antimicrobial stewardship programme targeting methicillin-resistant Staphylococcus aureus (MRSA).

RESULTS

The time to administer effective antimicrobials was significantly (median number of days, 3 before vs. 0 after, P < 0·001) shortened, and the rate of de-escalation was significantly elevated (47·1% vs. 96·2%, P < 0·001) after implementation of daily review. The 60-day clinical failure associated with Gram-positive bacterial infection was significantly reduced (33·3% vs. 17·6%, P = 0·007) after intervention.

WHAT IS NEW AND CONCLUSIONS

Daily review of administration of antimicrobials targeting MRSA was highly effective in improving clinical outcomes by optimizing early antimicrobial therapy.

Comprehensive analyses using next-generation sequencing and immunohistochemistry enable precise treatment in advanced gastric cancer

BACKGROUND

In advanced gastric cancer (AGC), most clinical trials are designed on the basis of protein expression or gene amplification of specific genes. Recently, next-generation sequencing (NGS) allowed us to comprehensively profile the tumor gene status. This study aimed to elucidate the profiling between gene alterations and protein expression in AGC to aid in future clinical trials on AGC.

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded tumor samples from 121 stage III/IV gastric cancer patients were examined for protein expression of tyrosine kinase receptors (RTKs; ERBB2, EGFR, c-MET, and FGFR2) using immunohistochemistry (IHC). Furthermore, 409 cancer-related genes were sequenced to detect mutations and copy number variations using NGS.

RESULTS

Most ERBB2 overexpression (IHC 3+) cases (80.0%) had ERBB2 amplification and did not have other RTK amplification or oncogene mutations. However, one-fourth of MET overexpression cases (25.0%) had ERBB2 alterations. EGFR and FGFR2 overexpression cases had ERBB2 alterations or other gene alterations such as KRAS or PIK3CA. On the other hand, most of the four RTK amplification cases (88.2%) were mutually exclusive with each amplification. However, RTK amplification did not simply correlate with protein overexpression, whereas cases with RTK high-level amplification had protein overexpression and rarely showed other co-existing gene alterations.

CONCLUSION

AGC involves a complicated arrangement of protein expression and gene alterations. Comprehensive analyses of NGS and IHC will be necessary to design the optimal therapy for treating the appropriate population of patients in future clinical trials.

Recurrent mutations of CD79B and MYD88 are the hallmark of primary central nervous system lymphomas

AIMS

Primary central nervous system lymphoma (PCNSL) manifest aggressive clinical behaviour and have poor prognosis. Although constitutive activation of the nuclear factor-κB (NF-κB) pathway has been documented, knowledge about the genetic alterations leading to the impairment of the NF-κB pathway in PCNSLs is still limited. This study was aimed to unravel the underlying genetic profiles of PCNSL.

METHODS

We conducted the systematic sequencing of 21 genes relevant to the NF-κB signalling network for 71 PCNSLs as well as the pyrosequencing of CD79B and MYD88 mutation hotspots in a further 35 PCNSLs and 46 glioblastomas (GBMs) for validation.

RESULTS

The results showed that 68 out of 71 PCNSLs had mutations in the NF-κB gene network, most commonly affecting CD79B (83%), MYD88 (76%), TBL1XR1 (23%), PRDM1 (20%) and CREBBP1 (20%). These mutations, particularly CD79B and MYD88, frequently coincided within each tumour in various combinations, simultaneously affecting diverse pathways within the network. No GBMs had hotspot mutation of CD79B Y196 and MYD88 L265.

CONCLUSIONS

The prevalence of CD79B and MYD88 mutations in PCNSLs was considerably higher than reported in systemic diffuse large B-cell lymphomas. This observation could reflect the paucity of antigen stimuli from the immune system in the central nervous system (CNS) and the necessity to substitute them by the constitutive activation of CD79B and MYD88 that would initiate the signalling cascades. These hotspot mutations may serve as a genetic hallmark for PCNSL serving as a genetic marker for diagnose and potential targets for molecular therapy.

The relationship between serum uric acid levels and β-cell functions in nondiabetic subjects

High serum uric acid (UA) levels are believed to be an independent risk factor for the development of diabetes. We aimed to investigate the relationship between serum UA concentrations and early-phase insulin secretion following a 75 g oral glucose tolerance test (OGTT) in nondiabetic subjects. We enrolled 570 Japanese subjects (354 males and 216 females, aged 50.5 ± 8.9 years and 52.6 ± 7.3 years, respectively), who underwent the 75 g OGTT during their annual health examination. The OGTT confirmed their nondiabetic status. Insulin secretion was estimated by the disposition index (DI) [(Δ insulin/Δ glucose (0-30 min) × (1/HOMA-IR)], which is an adjusted measure of β-cell function relative to variations in insulin sensitivity. Simple linear regression analysis showed negative correlations between serum UA levels and DI, when examined in the whole study population and female subjects only (r = -0.209, p < 0.001 and r = -0.232, p < 0.001, respectively). However, in male subjects, UA levels did not correlate with DI. In females, multivariate linear regression analysis revealed that serum UA levels were the major predictors of DI, explaining 16.4% of its variation (p < 0.001). Serum UA levels significantly correlate with early-phase insulin secretion in nondiabetic Japanese women. It may be an independent risk factor for predicting β-cell function in women.

The relationship between serum calcium level and early-phase insulin secretion in normoglycemic and pre-diabetic individuals

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is linked to altered calcium metabolism. However, little is known about the relationship between serum calcium levels and early-phase insulin secretion in subjects with normoglycemic tolerance (NGT) or prediabetes (preDM).

METHODS

In this gender-separated cross-sectional study, 352 subjects with NGT (215 men and 137 women; age: 48.8±9.1 years and 51.6±6.7 years, respectively) and 316 subjects with preDM (231 men and 85 women; age: 52.5±8.6 years and 54.2±8.0 years, respectively) were examined. Following a 75-g oral glucose tolerance test, early-phase insulin secretion was estimated using the insulinogenic index (IGI) [ΔInsulin(30-0 min)/ΔGlucose(30-0 min)].

RESULTS

Simple linear regression analysis showed that IGI was positively correlated with serum calcium and albumin-adjusted calcium levels in men with NGT and preDM. However, IGI was not correlated with calcium levels in women with NGT and preDM. Multivariate linear regression analysis of men with NGT revealed that the albumin-adjusted calcium level was the major predictor of IGI, responsible for 5.1% of its variation (P=0.003). In addition, in men with preDM, the albumin-adjusted calcium level was one of the predictors of IGI, responsible for 3.8% of its variation (P=0.004). These associations were independent of age, BMI, and HbA1c.

CONCLUSIONS

In non-diabetic Japanese men, serum calcium levels significantly correlate with early-phase insulin secretion. Serum calcium levels may be an independent predictor of β-cell function in men.

Effect of NS-018, a selective JAK2V617F inhibitor, in a murine model of myelofibrosis

A single somatic mutation, V617F, in Janus kinase 2 (JAK2) is one of the causes of myeloproliferative neoplasms (MPNs), including primary myelofibrosis, and the JAK2V617F mutant kinase is a therapeutic target in MPN. However, inhibition of wild-type (WT) JAK2 can decrease the erythrocyte or platelet (PLT) count. Our selective JAK2 inhibitor, NS-018, suppressed the growth of Ba/F3 cells harboring JAK2V617F more strongly than that of cells harboring WT JAK2. The 4.3-fold JAK2V617F selectivity of NS-018 is higher than the 1.0- to 2.9-fold selectivity of seven existing JAK2 inhibitors. NS-018 also inhibited erythroid colony formation in JAK2V617F transgenic mice at significantly lower concentrations than in WT mice. In keeping with the above results, in a JAK2V617F bone marrow transplantation mouse model with a myelofibrosis-like disease, NS-018 reduced leukocytosis and splenomegaly, improved bone marrow fibrosis and prolonged survival without decreasing the erythrocyte or PLT count in the peripheral blood. By exploring the X-ray co-crystal structure of NS-018 bound to JAK2, we identified unique hydrogen-bonding interactions between NS-018 and Gly993 as a plausible explanation for its JAK2V617F selectivity. These results suggest that NS-018 will have therapeutic benefit for MPN patients through both its efficacy and its reduced hematologic adverse effects.

Abstract P5-09-10: Androgen receptor signal acquired oncogenic role in aromatase inhibitor resistant model of breast cancer cell

Aromatase inhibitors (AI) are the common treatment for postmenopausal estrogen receptor (ER) positive breast cancer. However, not a few of these patients acquire resistance to AI.To investigate this molecular mechanism of resistance, we have established several breast cancer cell lines as AI resistant models. Recently, we reported on AD-EDR cells (androgen metabolite-dependent and estrogen depletion resistant cells) derived from MCF-7, in which ER activity depends on one of androgen metabolite, 5a-androstane-3β, 17β-diol (3βdiol).

It is supposed that tumor heterogeneity contributes to the acquired resistance to drugs.To examine this diversity, we established another AI resistant model derived from T-47D, to compare characters of these AI resistant models from different parents. Then, we found that the androgen receptor (AR) signal acquired oncogenic role in this model in contrast to AD-EDR cells established from MCF-7.

We cultured ER positive breast cancer cells, T47D-TE8, stably transfected with ERE-GFP reporter into T47D, under estrogen-depleted and androgen-supplemented conditions for more than three months, simulating the AI treatment, and established estrogen deprivation-resistant cells (TE8-EDR cells).

TE8-EDR cells had little ERE-GFP activity and proliferation response to estrogen though estrogen stimulated proliferation of parental T47D-TE8. The mRNA for ER and progesterone receptor was hardly detected in TE8-EDR cells. These results suggested that they had lost the ER-mediated pathway of growth. On the contrary, Dihydrotestosterone (DHT) increased growth of T47D-TE8 cells, while it was more remarkable in TE8-EDR, and this proliferative effect was reduced by AR antagonist, bicalutamide. The mRNA expressions of AR and its target gene, PSA, were extremely increased in TE8-EDR cells. These results indicated that TE8-EDR enhanced AR-regulated pathway for growth.

Increased AR expression was presumed to be one of the factors elevating AR activity. To identify other elements enhancing AR-mediated signal, we compared the gene expression of TE8-EDR cells with that of T47D-TE8 by microarray analysis. The outcome showed that the expression of some well-known androgen-related genes were increased in TE8-EDR cells. Among these genes, we focused on DDC (L-dopa decarboxylase) which has been reported as one of the AR coactivator, and its overexpression increase proliferative effect in prostate cancer cell lines.By real-time RT-PCR, we confirmed that the mRNA expression of DDC in TE8-EDR was higher over one-hundred fold than T47D-TE8. In addition, DHT-induced proliferation was cancelled by DDC inhibitor, NSD-1015.

This study suggests that TE8-EDR cells shift their growth pathway from ER to AR signal, and the AR activity is enhanced by high-expression of DDC. Whereas, MCF7-derived AD-EDR cells still depends on ER signal for their proliferation. So far, few studies have shown the proliferative effects of androgen as AI resistant mechanism. Our results provide new mechanism of acquired AI-resistance in breast cancer. Moreover, the fact that the character of AI resistant models varied with their parent cells supports the hypothesis that tumor heterogeneity contributes to diversify the mechanism of acquired resistance to hormonal therapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-10.