Probiotic Lactobacillus casei strain Shirota relieves stress-associated symptoms by modulating the gut-brain interaction in human and animal models

BACKGROUND

This study aimed to examine the effects of Lactobacillus casei strain Shirota (LcS) on gut-brain interactions under stressful conditions.

METHODS

Three double-blind, placebo-controlled trials were conducted to examine the effects of LcS on psychological and physiological stress responses in healthy medical students under academic examination stress. Subjects received LcS-fermented milk or placebo daily for 8 weeks prior to taking a national standardized examination. Subjective anxiety scores, salivary cortisol levels, and the presence of physical symptoms during the intervention were pooled and analyzed. In the animal study, rats were given feed with or without LcS for 2 weeks, then submitted to water avoidance stress (WAS). Plasma corticosterone concentration and the expression of cFos and corticotropin releasing factor (CRF) in the paraventricular nucleus (PVN) were measured immediately after WAS. In an electrophysiological study, gastric vagal afferent nerve activity was monitored after intragastric administration of LcS to urethane-anesthetized rats.

KEY RESULTS

Academic stress-induced increases in salivary cortisol levels and the incidence rate of physical symptoms were significantly suppressed in the LcS group compared with the placebo group. In rats pretreated with LcS, WAS-induced increases in plasma corticosterone were significantly suppressed, and the number of CRF-expressing cells in the PVN was reduced. Intragastric administration of LcS stimulated gastric vagal afferent activity in a dose-dependent manner.

CONCLUSIONS & INFERENCES

These findings suggest that LcS may prevent hypersecretion of cortisol and physical symptoms under stressful conditions, possibly through vagal afferent signaling to the brain and reduced stress reactivity in the PVN.

Fermented milk containing Lactobacillus casei strain Shirota prevents the onset of physical symptoms in medical students under academic examination stress

This pilot study investigated the effects of the probiotic Lactobacillus casei strain Shirota (LcS) on psychological, physiological, and physical stress responses in medical students undertaking an authorised nationwide examination for promotion. In a double-blind, placebo-controlled trial, 24 and 23 healthy medical students consumed a fermented milk containing LcS and a placebo milk, respectively, once a day for 8 weeks until the day before the examination. Psychophysical state, salivary cortisol, faecal serotonin, and plasma L-tryptophan were analysed on 5 different sampling days (8 weeks before, 2 weeks before, 1 day before, immediately after, and 2 weeks after the examination). Physical symptoms were also recorded in a diary by subjects during the intervention period for 8 weeks. In association with a significant elevation of anxiety at 1 day before the examination, salivary cortisol and plasma L-tryptophan levels were significantly increased in only the placebo group (P<0.05). Two weeks after the examination, the LcS group had significantly higher faecal serotonin levels (P<0.05) than the placebo group. Moreover, the rate of subjects experiencing common abdominal and cold symptoms and total number of days experiencing these physical symptoms per subject were significantly lower in the LcS group than in the placebo group during the pre-examination period at 5-6 weeks (each P<0.05) and 7-8 weeks (each P<0.01) during the intervention period. Our results suggest that the daily consumption of fermented milk containing LcS may exert beneficial effects preventing the onset of physical symptoms in healthy subjects exposed to stressful situations.

Abstract P4-03-03: Detection of the tumor vasculature and the hypoxic status of breast lesions using second-generation photoacoustic mammography: An exploratory study

Background: Tumor angiogenesis and hypoxia are associated with breast cancer growth and metastasis. Photoacoustic mammography (PAM) non-invasively visualizes hemoglobin distribution inside the breast by detecting thermoelastic waves from hemoglobin generated by the irradiation of a near-infrared laser pulse. Oxygen saturation (SO2) can be calculated using photoacoustic (PA) signals obtained by two laser pulses of different wavelengths. We further improved the spatial resolution of PAM by approximately 1 mm and enhanced detectability by using a high-sensitivity detector. This new PAM technique can obtain both PAM images and ultrasonography (US) images simultaneously. The aim of this study was to explore the clinical usefulness of this PAM technique.

Patients and methods: Women who had breast lesions were eligible for this study. The participants' lesions were measured using the new PAM technique before they began treatment. The PAM images were evaluated by 5 physicians. First, the lesions were identified using only the PAM images. Second, we used US or contrast-enhanced magnetic resonance images (CE-MRI) to identify the locations of the lesions. Next, we evaluated the photoacoustic (PA) signals based on their locations. Peri-tumoral PA signals were defined as linear signals that congregated in the peri-tumoral area, boundary PA signals were defined as peri-tumoral signals that were disrupted at the lesion's boundaries, and intra-tumoral PA signals were defined as any significant PA signals inside the tumor. SO2 was illustrated using a color scale. The study protocol was approved by the institutional review board at Kyoto University Hospital, Japan (UMIN000007464).

Results: PAM was performed on 48 breast lesions in 45 patients, including 36 invasive carcinoma lesions, 8 ductal carcinoma in situ (DCIS) lesions, and 4 benign lesions. Evaluations of PA signals according to the locations of the lesion, with confirmation from US or CE-MRI, were successfully performed for 38 lesions. Peri-tumoral PA signals were detected in 33 lesions (87%), disrupted boundary PA signals were detected in 30 lesions (79%), and intra-tumoral PA signals were detected in 25 lesions (66%). The detection rates for peri-tumoral, boundary and intra-tumoral PA signals were 94%, 87%, and 65% for invasive carcinoma, and 60%, 40%, and 80% for DCIS, respectively. Intra-tumoral PA signals tended to be weaker than peri-tumoral PA signals in invasive carcinoma lesions, and they often displayed a spotty rather than a linear shape. Intra-tumoral PA signals were observed to have lower SO2 levels than peri-tumoral PA signals in 95% of invasive carcinoma lesions and in 75% of DCIS lesions. Although peri-tumoral and boundary PA signals were also detected in a 38-mm fibroadenoma, the intra-tumoral PA signals displayed a diffuse pattern.

Conclusions: We demonstrated that high spatial resolution and use in combination with US and CE-MRI facilitate the region-specific evaluation of PAM imaging. PAM could become a useful tool for the evaluation of the hypoxic status of tumors by enhancing its sensitivity.

Citation Format: Takada M, Kawashima M, Kataoka M, Kanao S, Yamaga I, Torii M, Tokiwa M, Fakhrejahani E, Sakurai T, Asao Y, Haga H, Shiina T, Togashi K, Toi M. Detection of the tumor vasculature and the hypoxic status of breast lesions using second-generation photoacoustic mammography: An exploratory study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-03.

Criteria for diagnosis of DIC based on the analysis of clinical and laboratory findings in 345 DIC patients collected by the Research Committee on DIC in Japan

From analysis of the clinical and laboratory findings in the DIC patients collected by JRDC, diagnostic criteria for the diagnosis of DIC are proposed. The characteristics of the criteria are as follows: (1) a scoring system is adopted; (2) as the tests for scoring, PT, plasma Fbg level, serum FDP level, and platelet count are used; (3) different scores are given according to the grade of change in the results of the tests; (4) bleeding and clinical signs indicating organ dysfunction due to DIC are included in the scoring system; and (5) recognition of the well-known etiological factors of DIC is also scored.

The role of tissue thromboplastin in the development of DIC accompanying neoplastic diseases

Procoagulant activity of gastric cancer tissues and leukocytes obtained from various types of leukemia have been studied with special reference to TTP. The following results were obtained. Homogenates of APL leukocytes and gastric cancer tissues contained strong procoagulant activities, most of which have been identified as TTP since the activities were neutralized by a specific antibody against purified human placenta TTP, inactivated by the removal of phospholipid with heptane-butanol mixture, and inactivated by the addition of phospholipase C. The delipidated homogenates regained procoagulant activities by relipidation procedures. These results also confirmed that TTP from APL leukocytes and gastric cancer tissues have the same lipoprotein properties as those of TTP in normal tissues. Though slight proteolytic activity and fibrinolytic activity were demonstrated in the homogenate of gastric cancer tissues, it was noted that the TTP activity was different from these two activities by partial purification of TTP from gastric cancer tissues. The TTP activity of 9 homogenates of gastric cancer tissues was 301 +/- 289 (mean +/- SD) units per mg protein, being higher in homogenates of mucinous adenocarcinoma and signet-ring cell carcinoma than in those of tubular and poorly differentiated adenocarcinoma. The mean TTP activity of leukocyte homogenates from 14 patients with APL and one out of 4 patients with CML in blastic crisis was 81 +/- 76 units/10(7) cells. The TTP activity of the homogenates of leukocytes from 7 out of 18 patients with AML and another patient with CML in blastic crisis ranged from one to six units/10(7) cells with a mean of 3.3 +/- 1.2. The TTP activity of leukocyte homogenates from the other 11 cases of AML, two cases of CML in blastic crisis, 6 cases of CML, and one case each of ALL and CLL were less than one unit/10(7) cells. In leukemic patients, all cases with a value of more than 202 for the product of units of TTP activity per 10(7) cells and differential count (%) of leukemic cells in the bone marrow smear (MU value) were accompanied by DIC. The MU value of leukemic patients correlated well to the plasma fibrinogen and serum FDP levels. All patients with a MU value of more than 277 died of DIC when a sufficient amount of heparin was not administered. On the other hand, no DIC developed in any of the patients with a MU value of less than 90.(ABSTRACT TRUNCATED AT 400 WORDS)

Survival of HER2-positive primary breast cancer patients treated by neoadjuvant chemotherapy plus trastuzumab: a multicenter retrospective observational study (JBCRG-C03 study)

We investigated the disease-free survival (DFS) of HER2-positive primary breast cancer patients treated with neoadjuvant chemotherapy plus trastuzumab, as well as predictive factors for DFS and pathologic response. Data from 829 female patients treated between 2001 and 2010 were collected from 38 institutions in Japan. Predictive factors were evaluated using multivariate analyses. The 3-year DFS rate was 87 % [95 % confidence interval (CI) 85-90]. The pathologic complete response (pCR: ypT0/is + ypN0) rate was 51 %. The pCR rate was higher in the ER/PgR-negative patients than in the ER/PgR-positive patients (64 vs. 36 %, P < 0.001). Patients with pCR showed a higher DFS rate than patients without pCR (93 vs. 82 %, P < 0.001). Multivariate analysis revealed three independent predictors for poorer DFS: advanced nodal stage [hazard ratio (HR) 2.63, 95 % CI 1.36-5.21, P = 0.004 for cN2-3 vs. cN0], histological/nuclear grade 3 (HR 1.81, 95 % CI 1.15-2.91, P = 0.011), and non-pCR (HR 1.98, 95 % CI 1.22-3.24, P = 0.005). In the ER/PgR-negative dataset, non-pCR (HR 2.63, 95 % CI 1.43-4.90, P = 0.002) and clinical tumor stage (HR 2.20, 95 % CI 1.16-4.20, P = 0.017 for cT3-4 vs. cT1-2) were independent predictors for DFS, and in the ER/PgR-positive dataset, histological grade of 3 (HR 3.09, 95 % CI 1.48-6.62, P = 0.003), clinical nodal stage (HR 4.26, 95 % CI 1.53-13.14, P = 0.005 for cN2-3 vs. cN0), and young age (HR 2.40, 95 % CI 1.12-4.94, P = 0.026 for ≤40 vs. >40) were negative predictors for DFS. Strict pCR (ypT0 + ypN0) was an independent predictor for DFS in both the ER/PgR-negative and -positive datasets (HR 2.66, 95 % CI 1.31-5.97, P = 0.006 and HR 3.86, 95 % CI 1.13-24.21, P = 0.029, respectively). These results may help assure a more accurate prognosis and personalized treatment for HER2-positive breast cancer patients.

Forensic identification using multiple lot numbers of an implanted device

We report a case in which identification of a deceased individual was established using multiple lot numbers printed on a body implantable device. Autopsy of an unknown woman revealed an intramedullary nail inserted within her right femur. The device manufacturer was identified from the configuration of the intramedullary nail, and the "use history" was traced from lot numbers printed on the device's multiple parts. The deceased individual was thus identified as a woman who had attempted suicide by jumping from a height about a year previously and had been transported to a hospital and undergone surgery that included implantation of the intramedullary nail. The main factor contributing to the rapid identification was the manufacturer's and distributor's record of the use history (traceability) of the product, because of their accountability for purposes of quality control. A second contributing factor was multiple lot numbers, resulting in extremely low probability of the same combination of lot numbers being present in multiple individuals. This case confirmed the utility of multiple lot numbers of body implantable devices in forensic identification.

Abstract P2-03-09: Tissue hemoglobin oxygen saturation measured by photoacoustic mammography correlates with microvasculature properties assessed by histological image analysis, a preliminary study

Background: Photoacoustic mammography (PAM) is a new optical imaging technology with the potential of imaging tumor vasculature in breast cancer.The technique is applicable to the measurement of hemoglobin oxygen saturation (SO2).We have previously published an initial clinical result using a prototype machine (Canon Inc.,Tokyo, Japan) in breast cancer. We have also presented the morphological characteristics of tumor vessels analyzed by automated image processing during AACR annual meeting 2013. Here, we report the oxygenation data obtained by PAM in relation with histological assessment of tumor vasculature and hypoxia.

Methods: Forty-four breast lesions were evaluated by PAM in this IRB approved prospective study at Kyoto University Hospital, Japan. PAM evaluation was performed on both breasts whenever possible.SO2 was calculated in region of interest after the radiologist confirmed the signal was associated with the tumor location in MRI images. For the normal breast, signals obtained at the same depth of the tumor, were selected. Eighty-one histological sections from 20 available invasive carcinoma tissues at the time of this analysis were selected for immunohistochemical assessment of hypoxia by anti -carbonic anhydrase IX (CA IX) and tumor vasculature image analysis using anti-CD31. Five 0.5 mm2 area of each cancer and 3 area of normal mammary tissue associated with the same lesion were randomly selected from different sections. Total vascular area in each square was calculated by using Image Pro-Plus 7.0 software (Media Cybernetics, USA). Tumor-to-normal vascular area ratio (T/N VA) was calculated for each lesion as an index for tumor blood supply.

Results: Patients’ age ranged from 36 to 83 years old. Tumor associated signals were detected by PAM in 18 out of 20 lesions for which tissues were available for histological examination. SO2 in tumor was calculated 70.6% ±13.2 and 83.3% ±10.7 in the normal counterpart. While T/N VA ranged between 0.11 to 1.14, it was almost 3 times lower in lesions with CA IX positive cytoplasmic membrane staining (0.21 vs 0.7, p-value = 0.021 Mann-Whitney Test). Normalized tumor SO2 (tumor SO2/normal counterpart SO2) was significantly lower in the group with lower T/N VA (0.9 vs. 0.8,p-value = 0.045, Student T-test). To better evaluate the accuracy of PAM measurement in calculating SO2,3780 tumor-associated and 2835 normal microvessels were analyzed by image analysis software. Tumor associated vessels had significantly smaller area (p-value&lt;0.001) and vessels with irregular lumens were more frequent in tumor (76.5% vs 19.6% p-value &lt;0.001) compatible with lower SO2 in tumor areas.

Conclusion: Although the future result of our ongoing clinical studies of PAM measurement in breast cancer patients are more than necessary, the strong correlation between histological evaluation of hypoxia and angiogenesis with PAM measurement of oxygenation shows the promising prospective for clinical application of this new technology in breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-03-09.

Abstract P6-06-20: Predictive factors for pathologic complete response and disease-free survival after neoadjuvant chemotherapy with trastuzumab: A multicenter retrospective observational study in patients with HER2-positive primary breast cancer (JBCRG-C03 study)

BACKGROUND:

Addition of trastuzumab to neoadjuvant chemotherapy (NAC) improved pathologic complete response (pCR) rate in HER2-positive breast cancer. Although recent trials have shown favorable prognosis with NAC plus trastuzumab, clinicopathological factors to predict the outcome have not been fully understood. The aim of this study was to investigate the survival after NAC with trastuzumab and to explore the predictive factors.

PATIENTS AND METHODS:

This is a multicenter retrospective observational study. Patients with HER2-positive primary breast cancer treated with NAC plus trastuzumab from 2001 to 2010 were identified from the institutional database. Primary end point was disease-free survival (DFS). pCR was defined as ypT0/is+ypN0. Kaplan-Meier method was used to estimate DFS. Logistic regression and proportional hazard analysis were used to identify clinicopathological factors to predict pCR and DFS, respectively.

RESULTS:

733 patients were included in the analysis (whole dataset). 425 were ER/PgR-negative (HR- dataset) and 306 were ER/PgR-positive (HR+ dataset). Radiation therapy was performed in 90% of lumpectomy and 31% of mastectomy. Hormonal therapy was performed in 84% of HR+ dataset. pCR rate was 45% in whole dataset, 60% in HR- dataset, and 34% in HR+ dataset. Table 1 showed the result of multivariate analysis for pCR in whole dataset. When HR+ and HR- dataset were analyzed separately, no definitive predictors for pCR were identified in multivariate analysis. Although the patients with pCR showed a significantly favorable prognosis than those without pCR at 3 years DFS, in whole dataset (93% vs 83%, p&lt;0.0001) and HR- dataset (94% vs 80%, p&lt;0.0001), there was no significant difference in HR+ dataset (89% vs 86%, p = 0.10). Different predictors were selected for DFS when multivariate analysis was conducted separately between HR- and HR+ dataset (Table 2).

CONCLUSIONS:

In this observational study, we clarified predictors for pCR and DFS in HER2-positive patients treated with neoadjuvant trastuzumab containing therapy based on tumor subtype. Our results may help us to predict the prognosis more precisely and to simulate the disease course.

Table 1) Multivariate logistic regression analysis for pCR in whole datasetFactorsOR95%CIp-valuePost- vs Pre-menopause1.50(1.05-2.15)0.026*cT1-2 vs cT3-41.72(1.16-2.59)0.008*ER/PgR-negative vs ER/PgR-positive3.32(2.30-4.82)&lt;0.0001*Grade 3 vs 1-21.28(0.89-1.84)0.183

Table 2) Multivariate proportional hazard analysis for DFSFactors†HR95%CIp-valueWhole dataset   Pre- vs Post-menopause1.61(1.04-2.52)0.033*cN2-3 vs cN03.06(1.58-6.24)0.001*cN1 vs cN02.26(1.23-4.41)0.007*Grade 3 vs 1-21.87(1.20-2.97)0.006*non-pCR vs pCR1.90(1.18-3.13)0.008*HR- dataset   Pre- vs Post-menopause1.70(1.01-2.85)0.046*cT3-4 vs cT1-21.86(1.09-3.17)0.024*non-pCR vs pCR3.28(1.90-5.87)&lt;0.0001*HR+ dataset   cN2-3 vs cN05.01(1.79-16.19)0.002*cN1 vs cN03.50(1.40-10.61)0.006*Grade 3 vs 1-22.95(1.52-5.87)0.001*†Only factors with statistical significance

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-20.

Aircrew radiation dose estimates during recent solar particle events and the effect of particle anisotropy

A model was developed using a Monte-Carlo radiation transport code, MCNPX, to estimate the additional radiation exposure to aircrew members during solar particle events. The model transports an extrapolated particle spectrum based on satellite measurements through the atmosphere to aircraft altitudes. This code produces the estimated flux at a specific altitude where radiation dose conversion coefficients are applied to convert the particle flux into effective and ambient dose-equivalent rates. A cut-off rigidity model accounts for the shielding effects of the Earth's magnetic field. Comparisons were made between the model predictions and actual flight measurements taken with various types of instruments used to measure the mixed radiation field during ground level enhancements (GLEs) 60 and 65. An anisotropy analysis that uses neutron monitor responses and the pitch angle distribution of energetic solar particles was used to identify particle anisotropy for a solar event in December 2006. In anticipation of future commercial use, a computer code has been developed to implement the radiation dose assessment model for routine analysis.

Abstract P3-06-18: Increase of serum androgen and its metabolites in postmenopausal primary breast cancer patients with disease progression during neo-adjuvant exemestane treatment; JFMC 34–0601 TR

BACKGROUND: We reported a positive correlation between body mass index (BMI) and clinical response to neo-adjuvant hormonal therapy (NAH) with steroidal aromatase inhibitor, exemestane, in post-menopausal breast cancer patients (Takada M et al. Breast 2012). Here, we examined the relationship between serum concentrations of sex steroids and BMI, and explored their predictive value for clinical response.

PATIENTS AND METHODS: Among the 116 post-menopausal patients enrolled in the JFMC 34–0601 clinical trial of 24 weeks (wks) of NAH with exemestane, serums from 60 patients at pre-treatment, at 4wks and end of the treatment (24wks) were subjected to this study. Estradiol (E2), estrone (E1), dehydroepiandrosterone (DHEA), androstenedione (A-dione), 5-androstene-3β, 17β-diol (Aenediol), 5α-androstane-3β, 17β-diol (Aanediol) were measured using LC-MS/MS analysis and E1- sulfate (E1S) was by RIA.

RESULTS: There were no significant correlations between pre-treatment concentrations of sex steroids and BMI, except for moderate correlation of E2 and BMI (p = 0.004). In multivariate analysis, E1 was an independent predictive factor for objective response [odds 6.0, 95% confidence interval (CI) 1.5 — 34.6, p = 0.011], as well as BMI. All of the estrogens decreased to under-detection levels (0.5 for E1 and E2, 5 pg/assay for E1S) at 4 wks of treatment, and maintained through to the end of treatment in almost all patients independently of clinical response. The geometric mean percentage changes in androgens after NAH were: DHEA −0.2% (95%CI −15.3% — +17.6%) for patients without progressive disease (non-PD) and +44.8% (95%CI +22.1% — +71.8%) for patients with progressive disease (PD); A-dione −2.3% (95%CI −17.3% — +15.4%) for non-PD and +45.6% (95%CI +28.3% — +65.3%) for PD; Aenediol −11.5% (95%CI −20.6% — −1.4%) for non-PD and +24.9% (95%CI +1.9% — +53.0%) for PD; Aanediol +21.3% (95%CI −5.5% — +55.8%) for non-PD and +56.3% (95%CI +5.3% — +132.0%) for PD, respectively. The changes in the concentrations of both DHEA and A-dione in patients with PD were statistically significant (p = 0.008 and p = 0.002, respectively). In all of the PD patients, the serum concentrations of DHEA and A-dione were increased after NAH.

CONCLUSION: Pretreatment serum concentration of E1 was an independent predictive factor for clinical response to NAH with exemestane. Measurement of dynamics of the serum androgen concentrations might be helpful for monitoring treatment response, and mechanism of increase of androgens has a value for further investigation. Our results should be validated using a larger dataset. (UMIN ID; C000000345)

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-18.

p53 status and prognosis in stage I-IIIa non-small cell lung cancer

To investigate the role of p53 abnormalities in predicting the survival of patients with non-small cell lung cancer (NSCLC), polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and immunohistochemical analyses were performed on 74 and 67 tumor samples, respectively, from patients with pathological stage I-IIIa NSCLC. An abnormally migrating SSCP band was observed in 21 of 74 (28%) tumor specimens. DNA sequence analysis revealed 23 intragenic mutations including 3 small deletions and 20 point mutations. Immunohistochemical analysis using the DO-7 monoclonal antibody showed abnormal expression of p53 in 27 of 67 (40%) patients. The concordance rate between immunohistochemical and PCRSSCP analyses was 73% (49/67) in this study. Univariate and multivariate analyses demonstrated that abnormal expression of p53 may be associated with prolonged survival (p=0.0997 and 0.0099, respectively). In contrast, no relationship was observed between p53 mutation and overall survival (0.6968). These results suggest that p53 status and the survival outcome changes between immunohistochemical and mutational analyses in stage I-IIIa NSCLC.

Pyrroloquinoline quinone stimulates epithelial cell proliferation by activating epidermal growth factor receptor through redox cycling

Pyrroloquinoline quinone (PQQ), a redox cofactor for bacterial dehydrogenases, has been implicated to be an important nutrient in mammals functioning as a potent growth factor. However, the underlying molecular mechanisms have not been elucidated. The present study revealed that PQQ induces the activation (tyrosine autophosphorylation) of epidermal growth factor receptor (EGFR) and its downstream signaling in a ligand-independent manner, leading to increased cellular proliferation in an epithelial cell line A431. PQQ inhibited protein tyrosine phosphatase 1B (PTP1B), which negatively regulates the EGFR signaling by tyrosine dephosphorylation, to oxidatively modify the catalytic cysteine through its redox cycling activity to generate H(2)O(2). PQQ-inducible intracellular ROS production and EGFR activation were significantly suppressed by the pre-treatment with antioxidants. The intracellular redox state regulates the EGFR signaling through the redox-sensitive catalytic cysteine of PTP1B and modulates cell proliferation. Our data suggest that PQQ may stimulate epithelial cell proliferation by activating EGFR by oxidation and subsequent inactivation of PTP1B via its redox cycling. Our results provide novel insight into the mechanisms by which PQQ may function as a growth factor to contribute to mammalian growth.

Combined exposure to X-irradiation followed by N-ethyl-N-nitrosourea treatment alters the frequency and spectrum of Ikaros point mutations in murine T-cell lymphoma

Ionizing radiation is a well-known carcinogen, but its potency may be influenced by other environmental carcinogens, which is of practical importance in the assessment of risk. Data are scarce, however, on the combined effect of radiation with other environmental carcinogens and the underlying mechanisms involved. We studied the mode and mechanism of the carcinogenic effect of radiation in combination with N-ethyl-N-nitrosourea (ENU) using doses approximately equal to the corresponding thresholds. B6C3F1 mice exposed to fractionated X-irradiation (Kaplan's method) followed by ENU developed T-cell lymphomas in a dose-dependent manner. Radiation doses above an apparent threshold acted synergistically with ENU to promote lymphoma development, whereas radiation doses below that threshold antagonized lymphoma development. Ikaros, which regulates the commitment and differentiation of lymphoid lineage cells, is a critical tumor suppressor gene frequently altered in both human and mouse lymphomas and shows distinct mutation spectra between X-ray- and ENU-induced lymphomas. In the synergistically induced lymphomas, we observed a low frequency of LOH and an inordinate increase of Ikaros base substitutions characteristic of ENU-induced point mutations, G:C to A:T at non-CpG, A:T to G:C, G:C to T:A and A:T to T:A. This suggests that radiation doses above an apparent threshold activate the ENU mutagenic pathway. This is the first report on the carcinogenic mechanism elicited by combined exposure to carcinogens below and above threshold doses based on the mutation spectrum of the causative gene. These findings constitute a basis for assessing human cancer risk following exposure to multiple carcinogens.

Predictions of the pathological response to neoadjuvant chemotherapy in patients with primary breast cancer using a data mining technique

Nomogram, a standard technique that utilizes multiple characteristics to predict efficacy of treatment and likelihood of a specific status of an individual patient, has been used for prediction of response to neoadjuvant chemotherapy (NAC) in breast cancer patients. The aim of this study was to develop a novel computational technique to predict the pathological complete response (pCR) to NAC in primary breast cancer patients. A mathematical model using alternating decision trees, an epigone of decision tree, was developed using 28 clinicopathological variables that were retrospectively collected from patients treated with NAC (n = 150), and validated using an independent dataset from a randomized controlled trial (n = 173). The model selected 15 variables to predict the pCR with yielding area under the receiver operating characteristics curve (AUC) values of 0.766 [95 % confidence interval (CI)], 0.671-0.861, P value < 0.0001) in cross-validation using training dataset and 0.787 (95 % CI 0.716-0.858, P value < 0.0001) in the validation dataset. Among three subtypes of breast cancer, the luminal subgroup showed the best discrimination (AUC = 0.779, 95 % CI 0.641-0.917, P value = 0.0059). The developed model (AUC = 0.805, 95 % CI 0.716-0.894, P value < 0.0001) outperformed multivariate logistic regression (AUC = 0.754, 95 % CI 0.651-0.858, P value = 0.00019) of validation datasets without missing values (n = 127). Several analyses, e.g. bootstrap analysis, revealed that the developed model was insensitive to missing values and also tolerant to distribution bias among the datasets. Our model based on clinicopathological variables showed high predictive ability for pCR. This model might improve the prediction of the response to NAC in primary breast cancer patients.