Mph1p promotes gross chromosomal rearrangement through partial inhibition of homologous recombination

Gross chromosomal rearrangement (GCR) is a type of genomic instability associated with many cancers. In yeast, multiple pathways cooperate to suppress GCR. In a screen for genes that promote GCR, we identified MPH1, which encodes a 3'-5' DNA helicase. Overexpression of Mph1p in yeast results in decreased efficiency of homologous recombination (HR) as well as delayed Rad51p recruitment to double-strand breaks (DSBs), which suggests that Mph1p promotes GCR by partially suppressing HR. A function for Mph1p in suppression of HR is further supported by the observation that deletion of both mph1 and srs2 synergistically sensitize cells to methyl methanesulfonate-induced DNA damage. The GCR-promoting activity of Mph1p appears to depend on its interaction with replication protein A (RPA). Consistent with this observation, excess Mph1p stabilizes RPA at DSBs. Furthermore, spontaneous RPA foci at DSBs are destabilized by the mph1Delta mutation. Therefore, Mph1p promotes GCR formation by partially suppressing HR, likely through its interaction with RPA.     

The impact of chemokine receptor CXCR4 on breast cancer prognosis: A meta-analysis

Background: C-X-C chemokine receptor type 4 (CXCR4) has been implicated in the invasiveness and metastasis of diverse cancers. However, the published data remain controversial on the correlation between CXCR4 expression level, as well as its subcellular distribution in tumor cells, and the clinical outcome of patients with breast cancer. Methods: To identify the precise role of CXCR4 in the clinical outcome of breast cancer, we performed a meta-analysis including 15 published studies. Original data included the hazard ratios (HRs) of overall survival (OS) and disease-free survival (DFS) in breast cancer with high CXCR4 expression versus low expression. We pooled hazard ratios (HRs) with 95% confidence intervals (CIs) to estimate the hazard. Results: A total of 15 published studies (including 3104 patients) were eligible. Overall survival (OS) and disease-free survival (DFS) of breast cancer were found to be significantly related to CXCR4 expression level, with the HR being 1.65 (95%CI: 1.34–2.03; P < 0.00001) and 1.94 (95%CI: 1.42–2.65; P < 0.00001) respectively. Stratified analysis according to subcellular distribution of CXCR4 showed that high expression in whole cells, cytoplasm and nucleus could predict unfavorable OS, with the HR of 2.02 (95%CI: 1.43–2.85; P < 0.0001), 1.57 (95%CI: 1.13–2.18; P = 0.007), and 1.47 (95%CI: 1.19–1.81; P = 0.0004) respectively. As for DFS, elevated expression level of CXCR4 both in whole cells and cytoplasm predicted a poor outcome, with the HR being 2.23 (95%CI: 1.48–3.37; P = 0.0001) and 1.76 (95%CI: 1.11–2.80; P = 0.02), while high expression in the nucleus had no statistical significance, with HR 1.15 (95%CI: 0.52–2.55; P = 0.73). Conclusions: Increased CXCR4 expression, especially in whole cells and cytoplasm, may serve as a poor prognostic indicator in patients with breast cancer. Future studies are warranted to investigate the relationship between CXCR4 expression and survival of patients with breast carcinoma, which could help predict the clinical outcome and guide clinical decision-making for therapy.     

靶向Rad51与肿瘤治疗的研究进展

DNA损伤反应在维持细胞基因组稳定性和机体存活发挥重要作用。DNA双链断裂(Double strand breaks,DSBs)是DNA损伤最严重的形式。同源重组修复是体内参与DSBs损伤修复的重要机制之一,其中Rad51是体内参与同源重组性DNA修复的关键因子。Rad51在人类的多种肿瘤组织中高表达,如乳腺癌、非小细胞肺癌、前列腺癌等,与肿瘤的转移和恶化相关。如何有效下调肿瘤组织中的Rad51的水平,降低肿瘤细胞的DNA损伤修复能力,从而提高肿瘤治疗的疗效具有潜在的临床应用价值。本文对近年来的一个研究热点靶向Rad51在肿瘤治疗研究中的应用进行综述。     

Antihypertensive medications and survival in patients with cancer: A population-based retrospective cohort study

Background: The association between antihypertensive medications and survival in cancer patients remains unclear. Objectives: To explore the association between classes of antihypertensive drugs and survival in cancer patients. Methods: Provincial Cancer Registry data was linked with a Provincial Drug Program Information Network (DPIN) for patients with lung (n = 4241), colorectal (n = 3967), breast (n = 4019) or prostate (n = 3355) cancer between the years of 2004 and 2008. Cox regression analyses were used to compare survival of patients using beta blockers (BBs), angiotensin-converting enzyme inhibitors/receptor blockers (ACEi/ARB), calcium channel blockers (CCBs) or thiazide diuretics (TDs) to survival of patients who did not use any of these antihypertensive drugs. Survival of patients using only one class of antihypertensive drugs were compared to each other, with BBs as the reference class. Results: Compared to the antihypertensive drug non-user cohort, BBs had no effect on survival for any of the cancers. ACEi/ARBs use was weakly associated with increased deaths for breast cancer (HR: 1.22, 95% CI: 1.04–1.44) and lung cancer (HR: 1.11, 95% CI: 1.03–1.21) patients. Deaths were also increased with CCB use in patients with breast cancer (HR: 1.22, 95% CI: 1.02–1.47) and with TD use in lung cancer patients (HR: 1.1, 95% CI: 1.01–1.19). There was strong evidence (p-value <0.0001) of an increase in deaths with TD use for colorectal (HR: 1.28, 95% CI: 1.15–1.42), and prostate (HR 1.41, 1.2–1.65) cancer patients. When including only antihypertensive drug users prescribed one drug class, lung cancer patients receiving CCBs had improved survival compared to BBs (HR 0.79, 95% CI: 0.64–0.98). Conclusions: Some classes of antihypertensive agents are associated with a decreased survival in certain cancers. The decrease could be due to more comorbidities in antihypertensive drug users. However, CCB use was associated with improved survival in lung cancer patients.     

Contrast Enhancement on Cone-Beam Breast-CT for Discrimination of Breast Cancer Immunohistochemical Subtypes

PURPOSE: To evaluate whether contrast enhancement on cone-beam breast-CT (CBBCT) could aid in discrimination of breast cancer subtypes and receptor status. METHODS: This study included female patients age >40 years with malignant breast lesions identified on contrast-enhanced CBBCT. Contrast enhancement of malignant breast lesions was standardized to breast fat tissue contrast enhancement. All breast lesions were approved via image-guided biopsy or surgery. Immunohistochemical staining was conducted for expression of estrogen (ER), progesterone (PR), human epidermal growth factor receptor-2 (HER2) and Ki-67 index. Contrast enhancement of breast lesions was correlated with immunohistochemical breast cancer subtypes (Luminal A, Luminal B, HER2 positive, triple negative), receptor status and Ki-67 expression. RESULTS: Highest contrast enhancement was seen for Luminal A lesions (93.6 HU) compared to Luminal B lesions (47.6 HU, P = .002), HER2 positive lesions (83.5 HU, P = .359) and triple negative lesions (45.3 HU, P = .005). Contrast enhancement of HER2 positive lesions was higher than Luminal B lesions (P = .044) and triple negative lesions (P = .039). No significant difference was evident between Luminal B and triple negative lesions (P = .439). Lesions with high Ki-67 index showed lower contrast enhancement than those with low Ki-67 index (P = .0043). ER, PR and HER2 positive lesions demonstrated higher contrast enhancement than their receptor negative counterparts, although differences did not reach statistical significance (P = .1714; P = .3603; P = .2166). CONCLUSIONS: Contrast enhancement of malignant breast lesions on CBBCT correlates with immunohistochemical subtype and proliferative potential. Thereby, CBBCT might aid in selecting individualized treatment strategies for breast cancer patients based on pre-operative imaging.     

Luminal (Her2 negative) prognostic index and survival of breast cancer patients

PurposeThe group of luminal (Her2 negative) is distinguished from other subtypes of breast cancer. We aimed to produce a prognostic index specific for luminal (Her2 negative) subtype breast cancer that could assist clinical treatment.MethodsThe test set comprised 406 consecutive luminal (Her2 negative) breast cancer patients. The relationship of 11 clinicopathologic factors including survivin with the 5-year disease-free survival was analyzed.ResultsIn univariate analysis, TNM stage, surgery, tumor size, lymph node involvement, and survivin expression were prognostic factors. In multivariate analysis, tumor size [HR (95% CI): 1.98 (1.12–3.49), p = 0.019], the number of lymph node metastasis [HR (95% CI): 1.75 (1.33–2.29), p < 0.0001] and the expression of progesterone receptor [HR (95% CI): 0.58 (0.36–0.95), p = 0.029] can independently predict prognosis. Prognostic index (PI) was calculated as 0.68 × tumor size + 0.56 × the number of lymph node metastasis − 0.54 × PR. According to the PI, patients were categorized into three groups: low, middle, and high risk group with the 5-year disease-free survival rates of 91.91%, 84.97% and 70.47%, respectively (P < 0.001). In the validation set, the luminal prognostic index (LPI) remained significant.ConclusionThe LPI may be a useful tool for evaluating the outcome of patients with luminal (Her-2 negative) breast cancer.     

Impact of comorbidity on survival by tumour location: Breast,colorectal and lung cancer (2000–2014)

BackgroundTo assess the impact of comorbidity, measured by the Charlson Comorbidity Index (CCI), on survival in breast, colorectal and lung cancer.MethodsWe identified 3455 breast cancer, 3336 colorectal cancer and 2654 lung cancer patients through the Hospital del Mar cancer registry. The prevalence of comorbidities according to the CCI was calculated. Kaplan-Meier curves and the log-rank test were used to compare survival curves for each cancer location. Cox regression was used to calculate survival hazard ratios and 1-, 3- and 5-year mortality rate ratios adjusted by age, sex, CCI, place of first consultation, stage, treatment and period of diagnosis.ResultsThe overall unadjusted 5-year follow-up survival proportion was 82.6% for breast cancer, 55.7% for colorectal cancer, and 16.3% for lung cancer. Overall survival was associated with CCI ≥ 3 in breast cancer (HR: 2.33 95%CI: 1.76–3.08), colorectal cancer (HR: 1.39; 95%CI: 1.13–1.70) and lung cancer (HR: 1.22; 95%CI: 1.06–1.40). In breast cancer, the higher the CCI, the higher the adjusted mortality rate ratio and differences were greater in 5-year than in 1-year follow-up survival.ConclusionsComorbidity is a significant predictor of overall survival in cancer patients; however, it has a stronger impact on survival in breast cancer than in colorectal and lung cancer.     

Nanoscale analysis of clustered DNA damage after high-LET irradiation by quantitative electron microscopy – The heavy burden to repair

Low- and high-linear energy transfer (LET) ionising radiation are effective cancer therapies, but produce structurally different forms of DNA damage. Isolated DNA damage is repaired efficiently; however, clustered lesions may be more difficult to repair, and are considered as significant biological endpoints. We investigated the formation and repair of DNA double-strand breaks (DSBs) and clustered lesions in human fibroblasts after exposure to sparsely (low-LET; delivered by photons) and densely (high-LET; delivered by carbon ions) ionising radiation. DNA repair factors (pKu70, 53BP1, γH2AX, and pXRCC1) were detected using immunogold-labelling and electron microscopy, and spatiotemporal DNA damage patterns were analysed within the nuclear ultrastructure at the nanoscale level. By labelling activated Ku-heterodimers (pKu70) the number of DSBs was determined in electron-lucent euchromatin and electron-dense heterochromatin. Directly after low-LET exposure (5 min post-irradiation), single pKu70 dimers, which reflect isolated DSBs, were randomly distributed throughout the entire nucleus with a linear dose correlation up to 30 Gy. Most euchromatic DSBs were sensed and repaired within 40 min, whereas heterochromatic DSBs were processed with slower kinetics. Essentially all DNA lesions induced by low-LET irradiation were efficiently rejoined within 24 h post-irradiation. High-LET irradiation caused localised energy deposition within the particle tracks, and generated highly clustered DNA lesions with multiple DSBs in close proximity. The dimensions of these clustered lesions along the particle trajectories depended on the chromatin packing density, with huge DSB clusters predominantly localised in condensed heterochromatin. High-LET irradiation-induced clearly higher DSB yields than low-LET irradiation, with up to ∼500 DSBs per μm³ track volume, and large fractions of these heterochromatic DSBs remained unrepaired. Hence, the spacing and quantity of DSBs in clustered lesions influence DNA repair efficiency, and may determine the radiobiological outcome.     

Characterization of anticancer properties of 2,6-diisopropylphenol–docosahexaenoate and analogues in breast cancer cells

The present study describes the characterization and evaluation of novel anticancer conjugates, 2,6-diisopropylphenol–docosahexaenoate (PP–DHA), and its analogues including 2,4-diisopropylphenol–docosahexaenoate (DIPP–DHA), 2-isopropylphenol–docosahexaenoate (IPP–DHA), 2-cyclohexanephenol-docosahexaenoate (CHP–DHA) and phenol–docosahexaenoate (P–DHA) on breast cancer cell lines. Representative breast cancer cell lines, based on estrogen α receptor (ER) and oncogene Her-2 expression, were used and include MDA-MB-231 (ER-negative, Her-2-negative), MCF-7 (ER-positive, Her-2-negative) AU565 (ER-negative, Her-2-positive) and MDA-MB-361 (ER-positive, Her-2-positive). The PP–DHA conjugate significantly inhibited cell growth and induced cell loss in the breast cancer cell lines similarly; however, this conjugate was not effective against normal mammary epithelial cells. The effect of various conjugates were in PP–DHA > IPP–DHA > DIPP–DHA > CHP–DHA >> P–DHA order. PP–DHA and IPP–DHA conjugates were stable in human and mouse serum. Furthermore, the non-hydrolyzable amide-linked conjugate analogues affected breast cancer cells in a manner similar to that of the ester-linked conjugates. This suggests that ester-linked PP–DHA and IPP–DHA conjugates were stable during treatment to breast cancer cells due to structural hindrance. PP–DHA did not affect PPARα or PPARγ activities but its anticancer effects appear to be mediated in part though the inhibition of histone deacetylase (HDAC) activity. Further experiments are needed to confirm their molecular target and to test the effectiveness of these compounds in an in vivo model for their anticancer properties. In conclusion, these results suggest that the novel PP–DHA and IPP–DHA conjugates and their amide derivatives may be useful for the treatment of breast cancer.     

Measurement of DNA damage in peripheral blood by the γ-H2AX assay as predictor of colorectal cancer risk

The detection of γ-H2AX focus is one of the most sensitive ways to monitor DNA double-strand breaks (DSBs). Although changes in γ-H2AX activity have been studied in tumor cells in colorectal cancer (CRC), changes in peripheral blood lymphocytes (PBLs) have not been examined previously. We hypothesize that higher levels of irradiation-induced γ-H2AX in PBLs may be associated with an elevated risk of colorectal cancer (CRC). In a case-control study, the baseline and ionizing radiation (IR)-induced γ-H2AX levels in PBLs from frequency-matched 320 untreated CRC patients and 320 controls were detected by a laser scanning cytometer-based immunocytochemical method. We used unconditional multivariable logistic regression to evaluate CRC risk by using the ratio of IR-induced γ-H2AX to the baseline levels with adjustment of age, sex and smoking status. We found CRC cases had significantly higher γ-H2AX ratio (1.5 vs. 1.41, P < 0.0001) compared with controls. When using the median γ-H2AX ratio of controls as a cutoff point, we found higher γ-H2AX ratio was significantly associated with an increased risk of CRC (OR = 6.72, 95% CI = 4.54–9.94). Quartile analyses also showed significant dose–response relationship between higher γ-H2AX ratio and increased risk of CRC (P for trend < 0.0001). Age, sex, BMI and smoking status also influenced the association of γ-H2AX ratio with CRC risk; however, no interactions with γ-H2AX ratio were observed. These results support the premise that DSBs in peripheral blood as measured by γ-H2AX level might represent an intermediate phenotype to assess the risk of CRC. Future prospective studies are necessary to confirm our findings in independent populations.     

Blunt-ended DNA double-strand breaks induced by endonucleases PvuII and EcoRV are poor substrates for repair in Saccharomyces cerevisiae

Most mechanistic studies of repair of DNA double-strand breaks (DSBs) produced by in vivo expression of endonucleases have utilized enzymes that produce cohesive-ended DSBs such as HO, I-SceI and EcoRI. We have developed systems for expression of PvuII and EcoRV, nucleases that produce DSBs containing blunt ends, using a modified GAL1 promoter that has reduced basal activity. Expression of PvuII and EcoRV caused growth inhibition and strong cell killing in both haploid and diploid yeast cells. Surprisingly, there was little difference in sensitivities of wildtype cells and mutants defective in homologous recombination, nonhomologous end-joining (NHEJ), or both pathways. Physical analysis using standard and pulsed field gel electrophoresis demonstrated time-dependent breakage of chromosomal DNA within cells. Although ionizing radiation-induced DSBs were largely repaired within 4 h, no repair of PvuII-induced breaks could be detected in diploid cells, even after arrest in G2/M. Rare survivors of PvuII expression had an increased frequency of chromosome XII deletions, an indication that a fraction of the induced DSBs could be repaired by an error-prone process. These results indicate that, unlike DSBs with complementary single-stranded DNA overhangs, blunt-ended DSBs in yeast chromosomes are poor substrates for repair by either NHEJ or recombination.     

Induction of fusion-competent myoblast-specific gene expression during myogenic differentiation of Drosophila Schneider cells by DNA double-strand breaks or replication inhibition

Differentiation of Drosophila Schneider cells caused by DNA double-strand break (DSB)-inducing topoisomerase II (topo II) inhibitors were attenuated by ICRF-193, a non-DNA-damaging topo II inhibitor. ICRF-193 did not inhibit differentiation induced by neocarzinostatin (NCS), a drug that causes DNA DSBs independent of topo II. Schneider cells differentiated upon treatment with gamma-ray. These results suggest that DNA DSBs induce myogenic differentiation of Schneider cells. We also found DNA replication inhibitors, hydroxyurea (HU), aphidicolin, and ethylmethanesulfonate (EMS) induced myogenic differentiation of Schneider cells. HU-induced differentiation was inhibited upon pretreatment of cells with chemical inhibitors of PP 1/2A, p38 MAPK, JNK, and proteasome. RT-PCR analysis revealed that the expressions of fusion-competent myoblast-specific genes lmd, sns, and del were induced in Schneider cells upon treatment with NCS or HU, whereas expressions of three founder cell-specific genes, duf, ants, and rols, were undetectable. These results indicate that the expression of fusion competent-myoblast-specific genes is induced during myogenic differentiation of Drosophila Schneider cells by DNA DSBs or replication inhibition.     

Rhomboid domain containing 2 (RHBDD2): A novel cancer-related gene over-expressed in breast cancer

In the course of breast cancer global gene expression studies, we identified an uncharacterized gene known as RHBDD2 (Rhomboid domain containing 2) to be markedly over-expressed in primary tumors from patients with recurrent disease. In this study, we identified RHBDD2 mRNA and protein expression significantly elevated in breast carcinomas compared with normal breast samples as analyzed by SAGE (n = 46) and immunohistochemistry (n = 213). Interestingly, specimens displaying RHBDD2 over-expression were predominantly advanced stage III breast carcinomas (p = 0.001). Western-blot, RT-PCR and cDNA sequencing analyses allowed us to identify two RHBDD2 alternatively spliced mRNA isoforms expressed in breast cancer cell lines. We further investigated the occurrence and frequency of gene amplification and over-expression affecting RHBDD2 in 131 breast samples. RHBDD2 gene amplification was detected in 21% of 98 invasive breast carcinomas analyzed. However, no RHBDD2 amplification was detected in normal breast tissues (n = 17) or breast benign lesions (n = 16) (p = 0.014). Interestingly, siRNA-mediated silencing of RHBDD2 expression results in a decrease of MCF7 breast cancer cells proliferation compared with the corresponding controls (p = 0.001). In addition, analysis of publicly available gene expression data showed a strong association between high RHBDD2 expression and decreased overall survival (p = 0.0023), relapse-free survival (p = 0.0013), and metastasis-free interval (p = 0.006) in patients with primary ER-negative breast carcinomas. In conclusion, our findings suggest that RHBDD2 over-expression behaves as an indicator of poor prognosis and may play a role facilitating breast cancer progression.     

Enhanced cytotoxic activity of doxorubicin through the inhibition of autophagy in triple negative breast cancer cell line

BackgroundThe outcome of triple negative breast cancer is still poor and requires improvement with better therapy options. Autophagy has recently been shown to play a role in anticancer drug resistance. Therefore, we investigated if the effectiveness of doxorubicin was augmented by the inhibition of autophagy.MethodsMDA-MB-231 was used as a model cell line for triple negative breast cancer and 3-methyladenine was used as an inhibitor of autophagy. Cells were treated with 0.46–1.84 μM doxorubicin and 2.5–10 μM 3-methyladenine for 48 h. Cell death mode was examined with M30 and M65 ELISA assays. ROS level and LDH activity was examined and the cellular acidic compartment of cells was monitored by acridine orange staining. The expression of various autophagy and apoptosis related proteins/genes were evaluated with Western blotting and RT-qPCR respectively.ResultsSynergism was observed between the compounds (CI value < 1.0). RT-qPCR analysis revealed that the combination resulted in a down-regulation of autophagy-related genes. Moreover, the combination resulted in a different cell death modality, upregulating necroptosis-related genes. This suggests that the mode of cell death may switch from apoptosis to necroptosis, which is a more severe form of cell death, when autophagy is inhibited. These results were further confirmed at protein level by Western blotting.ConclusionInhibition of autophagy seems to sensitize triple negative breast cancer cells to doxorubicin, warranting further in vivo studies for the proof of this concept.General significanceAutophagy has a key role in drug resistance in MDA-MB-231 cells. Therefore combinatorial approaches may effectively overcome resistance.     

Prompt repair of hydrogen peroxide-induced DNA lesions prevents catastrophic chromosomal fragmentation

Iron-dependent oxidative DNA damage in vivo by hydrogen peroxide (H₂O₂, HP) induces copious single-strand(ss)-breaks and base modifications. HP also causes infrequent double-strand DNA breaks, whose relationship to the cell killing is unclear. Since hydrogen peroxide only fragments chromosomes in growing cells, these double-strand breaks were thought to represent replication forks collapsed at direct or excision ss-breaks and to be fully reparable. We have recently reported that hydrogen peroxide kills Escherichia coli by inducing catastrophic chromosome fragmentation, while cyanide (CN) potentiates both the killing and fragmentation. Remarkably, the extreme density of CN + HP-induced chromosomal double-strand breaks makes involvement of replication forks unlikely. Here we show that this massive fragmentation is further amplified by inactivation of ss-break repair or base-excision repair, suggesting that unrepaired primary DNA lesions are directly converted into double-strand breaks. Indeed, blocking DNA replication lowers CN + HP-induced fragmentation only ∼2-fold, without affecting the survival. Once cyanide is removed, recombinational repair in E. coli can mend several double-strand breaks, but cannot mend ∼100 breaks spread over the entire chromosome. Therefore, double-strand breaks induced by oxidative damage happen at the sites of unrepaired primary one-strand DNA lesions, are independent of replication and are highly lethal, supporting the model of clustered ss-breaks at the sites of stable DNA-iron complexes.     

Contrast-Enhanced CT Density Predicts Response to Sunitinib Therapy in Metastatic Renal Cell Carcinoma Patients

The first-line therapy in metastatic renal cell carcinoma (mRCC), sunitinib, exhibits an objective response rate of approximately 30%. Therapeutic alternatives such as other tyrosine kinase inhibitors, VEGF inhibitors, or mTOR inhibitors emphasize the clinical need to predict the patient's response to sunitinib therapy before treatment initiation. In this study, we evaluated the prognostic value of pretreatment portal venous phase contrast-enhanced computed tomography (CECT) mean tumor density on overall survival (OS), progression-free survival (PFS), and tumor growth in 63 sunitinib-treated mRCC patients. Higher pretreatment CECT tumor density was associated with longer PFS and OS [hazard ratio (HR) = 0.968, P = .002, and HR = 0.956, P = .001, respectively], and CECT density was inversely correlated with tumor growth (P = .010). Receiver operating characteristic analysis identified two CECT density cut-off values (63.67 HU, sensitivity 0.704, specificity 0.694; and 68.67 HU, sensitivity 0.593, specificity 0.806) which yielded subpopulations with significantly different PFS and OS (P < .001). Pretreatment CECT is therefore a promising noninvasive strategy for response prediction in sunitinib-treated mRCC patients, identifying patients who will derive maximum therapeutic benefit.     

Oxytocin attenuates deficits in social interaction but not recognition memory in a prenatal valproic acid-induced mouse model of autism

Recent studies have reported that oxytocin ameliorates behavioral abnormalities in both animal models and individuals with autism spectrum disorders (ASD). However, the mechanisms underlying the ameliorating effects of oxytocin remain unclear. In this study, we examined the effects of intranasal oxytocin on impairments in social interaction and recognition memory in an ASD mouse model in which animals are prenatally exposed to valproic acid (VPA). We found that a single intranasal administration of oxytocin restored social interaction deficits for up to 2 h in mice prenatally exposed to VPA, but there was no effect on recognition memory impairments. Additionally, administration of oxytocin across 2 weeks improved prenatal VPA-induced social interaction deficits for at least 24 h. In contrast, there were no effects on the time spent sniffing in control mice. Immunohistochemical analysis revealed that intranasal administration of oxytocin increased c-Fos expression in the paraventricular nuclei (PVN), prefrontal cortex, and somatosensory cortex, but not the hippocampal CA1 and CA3 regions of VPA-exposed mice, suggesting the former regions may underlie the effects of oxytocin. These findings suggest that oxytocin attenuates social interaction deficits through the activation of higher cortical areas and the PVN in an ASD mouse model.     

Enhanced neuroprotective effect of mild-hypothermia with VPA against ethanol–mediated neuronal injury

Introduction

Progress in understanding pathophysiological mechanisms and the development of targeted regenerative strategies have been hampered by the lack of predictive disease models, specifically for the conditions to which affected cell types are inaccessible. The present study has aimed to unearth the role of valproic acid (VPA) and mild hypothermia (MH) as promising strategy to enhance the neuroprotective mechanisms in undifferentiated and differentiated human neural precursor cells (hNPCs) against ethanol-induced damage.

Pre-diagnostic smoking behaviour and poorer prognosis in a German breast cancer patient cohort – Differential effects by tumour subtype,NAT2 status,BMI and alcohol intake

BackgroundInconsistent associations of smoking and breast cancer-specific mortality might be explained by subgroups of patients with different susceptibility to harmful effects of smoking.MethodsWe used a prospective cohort of 3340 postmenopausal breast cancer patients aged 50–74 and diagnosed with invasive tumours 2001–2005 in Germany, with a median follow-up time of 6 years. The effect of pre-diagnostic smoking behaviour on mortality outcomes and risk of recurrence was investigated using delayed entry Cox regression analysis. Differential effects according to N-acetyltransferase (NAT2) status, BMI, alcohol consumption, and tumour subtypes were assessed.ResultsOverall, smoking at time of breast cancer diagnosis versus never/former smoking was non-significantly associated with increased breast cancer-specific mortality and risk of recurrence (HR 1.23, 95% CI 0.93–1.64, and HR 1.29, 95% CI 0.95–1.75, respectively). Associations were consistently stronger in NAT2 slow than in fast acetylators for all mortality outcomes. Breast cancer-specific mortality was significantly increased in smokers with NAT2 slow acetylating status (HR 1.77, 95% CI 1.13–2.79) but not in those with fast acetylating status (HR 1.09, 95% CI 0.60–1.98; P_{heterogeneity} = 0.19). Smoking was associated with significantly poorer outcomes for triple negative and luminal A-like tumours (e.g. all-cause mortality: HR 1.93, 95% CI 1.02–3.65, and HR 2.08, 95% CI 1.40–3.10, respectively). Risk of recurrence was significantly increased for women with HER2 positive tumours (HR 3.64, 95% CI 1.22–10.8). There was significant heterogeneity by BMI for non-breast cancer-specific mortality (<25 kg/m²: HR 2.52, 95% CI 1.52–4.15 vs. ≥25 kg/m²: HR 0.94, 95% CI 0.38–2.36; P_{heterogeneity} = 0.04).ConclusionThe harmful effects of smoking may be particularly relevant for certain subgroups of breast cancer patients. This may include patients with NAT2 slow acetylation status or with tumour subtypes other than luminal B, such as luminal A tumours who usually have a rather good prognosis. Emphasis on smoking cessation programmes for all cancer patients should be strengthened.