Two GABAergic intraglomerular circuits differentially regulate tonic and phasic presynaptic inhibition of olfactory nerve terminals

Olfactory nerve axons terminate in olfactory bulb glomeruli forming excitatory synapses onto the dendrites of mitral/tufted (M/T) and juxtaglomerular cells, including external tufted (ET) and periglomerular (PG) cells. PG cells are heterogeneous in neurochemical expression and synaptic organization. We used a line of mice expressing green fluorescent protein under the control of the glutamic acid decarboxylase 65-kDa gene (GAD65+) promoter to characterize a neurochemically identified subpopulation of PG cells by whole cell recording and subsequent morphological reconstruction. GAD65+ GABAergic PG cells form two functionally distinct populations: 33% are driven by monosynaptic olfactory nerve (ON) input (ON-driven PG cells), the remaining 67% receive their strongest drive from an ON-->ET-->PG circuit with no or weak monosynaptic ON input (ET-driven PG cells). In response to ON stimulation, ON-driven PG cells exhibit paired-pulse depression (PPD), which is partially reversed by GABA(B) receptor antagonists. The ON-->ET-->PG circuit exhibits phasic GABA(B)-R-independent PPD. ON input to both circuits is under tonic GABA(B)-R-dependent inhibition. We hypothesize that this tonic GABA(B)R-dependent presynaptic inhibition of olfactory nerve terminals is due to autonomous bursting of ET cells in the ON-->ET-->PG circuit, which drives tonic spontaneous GABA release from ET-driven PG cells. Both circuits likely produce tonic and phasic postsynaptic inhibition of other intraglomerular targets. Thus olfactory bulb glomeruli contain at least two functionally distinct GABAergic circuits that may play different roles in olfactory coding.

Luminal group may give more benefit for invasive micropapillary carcinoma component breast cancer patients: experience from Cancer Hospital Fudan University

Abstract #6152

Objective: Comparative studies on clinical features and outcomes of very rare invasive micropapillary carcinoma of breast cancer of 4 subtypes by immunohistochemistry staining.
 Methods: From Aug 2005 to Mar 2008, a total of 52 breast cancer patients(BCPs) with an invasive micropapillary component (IMPC) among 1951 Chinese BCPs with complete of clinicopathologic data in our institution were enrolled into a retrospective analysis. We characterized all these 52 patients and analyzed using various parameters.
 Results: The 52 cases of breast carcinoma with an IMPC all occurred in women. Mean age was 51 years (range from 26-82). All of these patients had breast masses; one also had metastasis to the supraclavicular lymph node at the time of diagnosis., mean tumor size was 2.83cm(T2), 23.08%(12/52) was pure invasive micropapillary carcinoma, and lymph node positive percentage was 75.59 %( 36/51).Fifty one patients received surgery, while one of them lost the chance of surgery. Forty of them received the modified mastectomy while one was performed lumpectomy due to old age. One was performed LAND alone and four were performed lumpectomy and sentinel lymph node biopsy.
 By using IHC staining, when we regard HER2/neu 0 and +as negative. The Luminal A group, Luminal B, trip-negative, HER2+ /ER- were 76.92% (40/52), 11.54 %( 6/52), 7.69 %( 4/52), 3.85 %( 2/52), respectively. Compared to the database of 2005 breast cancer carcinoma in our institution, there was more Luminal A group patients than the whole group (P=0.01, chi-square test.), more Luminal B (P=0.028, Fisher exact possibility test), less trip-negative group (P=0.001, chi-square test). The positive lymph node among the Luminal A group, Luminal B, trip-negative, HER2+ /ER- were 65%,80%, 100%, 100%, respectively, while the lymphvascular invasion were 55%,33.33%,50%,50%,respectively, Mulifocality in Luminal A was 25% , 16.67% in Luminal B , while 50% in both trip-negative and HER2+/ER-.
 Twenty-one of them received both anthracyclines and Taxane, while 27 only received anthracyclines, Four patients only were received only AIs due to old age. All the luminal group patients received endrocine therapy after chemo. After nearly 14 months (2∼34 months) follow up, thirty-six women were disease free, one had local recurrence, and 1 had lung metastasis, while 1 had ovary carcinoma when the diagnosis of breast malignant, one patient lost following up due to mental disorder. Among the luminal B, one had metastasis when diagnosis, others were disease free. One woman of the trip-negative died of non-breast cancer disease,the HER2+/ER- group was no recurrence or metastasis.
 Discussion: The prelimary results showed that more luminal group in the IMPC may get benefit from the endocrine therapy. However the number of these cases is small and follow-up time is not very long, further studies are necessary to explain these rare and unique pattern of invasive carcinoma.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6152.

Seroma formation after breast cancer surgery and its risk factors

Abstract #4085

Background:. Seroma formation is one of the most common complications after breast cancer surgery including modified radical mastectomy and breast conservative surgery. Our study aims to investigate the risk factors of postoperative seroma in Chinese breast cancer patients.
 Methods: Clinical data of 158 women who underwent surgerical therapy for breast cancer in our hospital were collected prospectively and all patients were followed up. The risk factors for seroma occurrence were compared between the seroma group and control group using X 2 test or t test, as well as the logistic regression was used as multivariate analysis.
 Results: Univariate analysis showed that the average age of the seroma group was significantly higher than those without seroma formation(58.71vs51.00, P=0.0019), but the total serum protein and albumin content were lower (68.47g/L vs 72.53g/L, P=0.009 and 40.75g/L vs 42.52g/L,P=0.020, respectively). In seroma group, the drainage volume of the first three days, the total and daily drainage volume were all higher (all p values less than 0.01), as well as drainage duration and hospital stay were longer(8.3d vs 14.4d, P=0.000 and 11.5d vs 23.7d, P=0.000, respectively). Logistic regression showed that older patients (OR=1.080, 95%CI 1.016∼1.148, P=0.013), lower total serum protein content(OR=0.814, 95%CI 0.705∼0.940, P=0.005)and higher drainage volume in d1(OR=1.009, 95%CI 1.001∼1.016, P=0.022) and d3 (OR=1.017, 95%CI 1.005∼1.029, P=0.005) were all independent risk factors for subcutaneous seroma. The daily average drainage curve showed a gradually decreasing trend with a highest collections in the first three days. The seroma group had significantly higher average daily drainage volume( P=0.034) and longer duration (P=0.000).
 Conclusion:The risk factors of seroma formation after breast cancer surgery are complicated. However in order to prevent its occurrence effectively, the factors including age, nutrition status and daily drainage volume should be taken into consideration.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4085.

Clinicopathological features of the triple-negative tumors in Chinese breast cancer patients

Abstract #6080

Background: Triple negative breast cancers are defined by a lack of expression of estrogen, progesterone, and Her-2 receptors. A number of studies suggested that the triple-negative phenotype could contribute to an aggressive behavior and a poor prognosis. However, similar data is still not available for Chinese populations. We sought to analyze the clinicopathological features of this subgroup in our hospital in order to get characteristics for Chinese breast cancer.
 Methods: We performed a retrospective study of 2028 female unilateral breast cancer patients undergoing surgery in our hospital from February 1991 to December 2003. ER, PR and Her-2 status were assessed using immunohistochemical staining. Survival curves were performed with Kaplan-Meier method and annual recurrence hazard was estimated by hazard function.
 Results: According to different combinations of hormone receptor (HR) and Her-2 status, 2028 patients were categorized into the three subgroups as follows: Her-2+ (32.25%), HR+/Her-2- (48.92%) and triple-negative (18.83%). Triple-negative tumors were larger (greater than 2 cm in diameter) than HR+/Her-2- tumors, but smaller than Her-2+ tumors (70.03%, 66.15% and 76.15% respectively, P < 0.001). In addition, 21.99% of patients whose tumors were triple-negative had four or more axillary nodes involved compared with 27.37% of patients with Her-2+ tumors and 22.78% with HR+/Her-2- tumors (P = 0.004). There were statistical differences in the distribution of TP53 mutation and Cathepsin-D status (P < 0.001 for both). In the univariate analysis, we found a statistical significance for recurrence-free survival (RFS) among the three subgroups (P = 0.0036), with the rate of 72.89% for Her-2+ tumors, 78.26% for HR+/Her-2- tumors and 75.61% for triple-negative tumors at the 11th year respectively. When it came to the time of hazard peaks, discrepancies existed in different subgroups. Triple-negative patients showed an early major recurrence surge peaking at the 2.5th year after surgery, followed by a gradual decline until year 6.5 and then a modest increase. As to HR+/Her-2- patients, the hazard plot exhibited a wide initial plateau-like wave covering at least 4 years and a subsequent rise. The hazard rate for Her-2+ patients displayed a tapering sharp at the 1st year and a second rise. Furthermore, the first peak of triple-negative tumors was higher than that of HR+/Her-2- patients, but lower than that of Her-2+ ones.
 Conclusions: The recurrence pattern for triple-negative tumors was intermediate between Her-2+ and HR+/Her-2- counterparts.Our findings suggested that biological characteristics and prognosis of Chinese triple-negative breast cancer might be more favorable and somewhat different from those in Western populations.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6080.

The new understanding of two-sided role of glutathione S-transferase M1 in breast cancer susceptibility

Abstract #3098

[Background and purpose] Although glutathione S-transferase M1 (GSTM1) enzyme occupies a key position in biological detoxification processes by catalyzing the glutathione conjugation of carcinogens, GSTM1 gene is genetically deleted (referred as GSTM1-null or GSTM1-/-) in a high percentage of the Eurasian populations. Numerous studies have examined the association of GSTM1-/- with breast cancer yielding inconsistent results. In addition, few genetic variants in this gene have been explored. We set out to systematically evaluate the contributions of GSTM1 gene deletion/presence and common variants in GSTM1 to breast cancer, followed by functional studies.
 [Methods and Results] In the present study, we show that GSTM1-/- does confer a weak increased risk of breast cancer compared with GSTM1-present genotype, being confirmed by a meta-analysis of combining 40 related studies with the current case-control study (921 cases vs. 711 controls) of Chinese population (overall odds ratio of 1.10, 95% confidence interval: 1.04-1.15, P<0.001). Unexpectedly, GSTM1 homozygous wild-type (+/+) is also associated with a risk of breast cancer compared with heterozygous (+/-) individuals on the basis of accurate classification using long-PCR-based assay. Furthermore, for the population with one allele of GSTM1 (GSTM1+/-) accounting for 30-50%, we genotype four common single nucleotide polymorphisms (SNPs) spanning GSTM1 gene and identify a functional variant g.-498C>G in the putative promoter region associated with breast cancer risk. It displays that minor -498G allele is significantly more frequent in breast cancer controls than in cases (odds ratio of 0.51, 95% confidence interval: 0.30-0.86, P=0.012). This allele also leads to significantly reduced promoter activity compared to the major -498C allele. Further studies reveal the -498G can modify AP-2 binding site and decrease GSTM1 transcription. Among the three AP-2 isoforms, AP-2α provides the predominant regulation effect on this SNP.
 [Conclusions] These results indicate that the effect of GSTM1 genotypes conferring to breast cancer susceptibility is not dosage-dependent as taken for grant previously. GSTM1 has a two-sided role in breast cancer susceptibility; too high or too low expression of GSTM1 is not beneficial. We recommend that the complicated genetic predisposition of GSTM1 be considered when predicting breast cancer susceptibility using single or a panel of genetic variants.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3098.

Time distributions and prognosis factors of breast cancer recurrence in different sites after operation

Abstract #2080

Objective Our study aims to analyze the breast caner patients with different sites of recurrence, and to have knowledge of the regular patterns and influence factors of metastastic breast cancer.
 Methods We performed a retrospective study of 210 female breast cancer patients who were continuously followed up in our hospital from January 2005 to May 2007 and had complete data of metastasis. The clinical and biological characteristics were compared between the patients with organ metastases (lung, liver, brain) and non-viscera metastases (lymph node, bone).
 Results Cox regression analysis-hazard function showed that patients with elder age (RR=0.927 95%CI 0.877∼0.981, P=0.008) and HER-2 negative(RR=0.253 95%CI 0.076∼0.836, P=0.024)tended to develop non-viscera metastases, while patients with larger tumors (RR=3.832 95%CI 1.073∼13.687, P=0.039) tended to develop organ metastasesp.
 
 When stratified by the prognostic factors, the annual risk hazard curve of the patients with high risk of recurrence had double peaks at the second year and the ninth years after mastectomy respectively, and it was significantly higher than those of the patients with middle and low risk.[figure1]Annual risk hazard curves of both local relapse and metastasis also showed a double-peaked pattern. The curves for lymph node, bone, lung and liver metastasis showed a similar pattern, but all the peaks of curve emerged later than that of the local relapse.
 
 Conclusion Patients with different clinical and biological characteristics may develop recurrence in different sites. There are certain regular patterns of time distribution for different metastasis sites after mastectomy. The local recurrence may be the foreboding for the metastasis and we should pay attention to the local relapse signs especially in the patients with high risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2080.

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A novel lipopeptide produced by a Pacific Ocean deep-sea bacterium, Rhodococcus sp. TW53

AIMS

Our goal was to find a novel, biosurfactant-producing bacterium from Pacific Ocean deep-sea sediments.

METHODS AND RESULTS

An oil-degrading biosurfactant-producing bacterium TW53 was obtained from deep-sea sediment, and was identified through 16S rDNA analysis as belonging to the genus Rhodococcus. It lowered the surface tension of its culture to 34.4 mN m(-1). Thin layer chromatography (TLC) showed that the crude biosurfactants of TW53 were composed of lipopeptides and free fatty acids (FA). The lipopeptides were purified with column chromatography and then hydrolysed with 6 mol l(-1) HCl. Gas chromatography-mass spectrometry analysis showed that the hydrolyte in the hydrophobic fraction contained five kinds of FA with chain lengths of C(14)-C(19), and C(16)H(32)O(2) was a major component making up 59.18% of the total. However, 3-hydroxyl FA was not found, although it is usually found in lipopeptides. Silica gel TLC revealed that the hydrolyte in the hydrophilic fraction was composed of five kinds of amino acids; consistently, ESI-Q-TOF-MS analysis confirmed the composition results and provided their sequence tentatively as Ala-Ile-Asp-Met-Pro. Furthermore, the yield and CMC (critical micelle concentrations) of purified lipopeptides were examined. The purified product reduced the surface tension of water to 30.7 mN m(-1) with a CMC value of 23.7 mg l(-1). These results suggest that Rhodococcus sp. TW53 produces a novel lipopeptide that we have named rhodofactin.

CONCLUSION

The deep-sea isolate Rhodococcus sp. TW53 was the first reported lipopeptide-producing bacterium of this genus. The lipopeptides had novel chemical compositions.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rhodococcus sp. TW53 has potential in the exploration of new biosurfactants and could be used in bioremediation of marine oil pollution.

Dose-dependent protective effect of propofol against mitochondrial dysfunction in ischaemic/reperfused rat heart: role of cardiolipin

BACKGROUND AND PURPOSE

Ischaemia damages to the cardiac mitochondria by increasing generation of reactive oxygen species (ROS) and peroxidation of cardiolipin. The inhibited mitochondrial function leads to the cardiac injury during reperfusion. Propofol (2, 6-diisopropylphenol), an intravenous anaesthetic, has been shown to decrease cardiac ischaemia and reperfusion injury. In the present study, we propose that propofol protects mitochondrial function and decreases cardiac injury by prevention of cardiolipin peroxidation during ischaemia and reperfusion.

EXPERIMENTAL APPROACH

After isolation of mitochondria from isolated rat heart perfused on a Langendorff model, various mitochondrial bioenergetic parameters were evaluated such as rates of mitochondrial oxygen consumption, H(2)O(2) production, complex I and III activity as well as the degree of lipid peroxidation and cardiolipin content. The action of propofol was also explored in isolated mitochondria. And the effect of cardiolipin was evaluated by fusing cardiolipin liposome with mitochondria.

KEY RESULTS

Propofol treatment had strong dose-dependent protection attenuating these parameters alterations in reperfused rat heart and isolated mitochondria. Additionally, cardiolipin treatment had the same protective effect, compared with propofol treatment at high concentration.

CONCLUSIONS AND IMPLICATIONS

The protective effect of propofol appears to be due, at least in part, as a chemical uncoupler, to the interruption of the vicious circle of ROS-cardiolipin-complexes of the respiratory chain-ROS through preserving the content and integrity of cardiolipin molecules by ROS attack. These findings may provide an explanation for some of the factors responsible for cardioprotection and one approach exploring an available antioxidant.

A comparison of tumor characteristics between ER+/PR+ and ER+/PR- breast tumors in Chinese women

21097

Background: Although breast caner patients with any one of the two sex hormone receptors positive can be treated with endocrine therapy, many clinical data showed that there was different response to endocrine therapy for patients with ER+/PR+ and with ER+/PR- tumors. The aim of this study was to find out the factors related to PR expression by comparing the ER+/PR+ tumors and ER+/PR- tumors clinically and biologically. Methods: Between January 1990 to August 2006, 5,191 female breast cancer patients with known ER/PR expression status who received operation in our hospital were enrolled onto this retrospective study. Clinical and biological features of 2,227 patients with ER+/PR+ tumors were compared with those of 909 patients with ER+/PR- tumors. χ2 test was used for univariate analysis and logistic regression for multivariate analysis. Disease-free survival (DFS) and overall survival (OS) was calculated using Kaplan-Meier analyses, and all statistical tests were two-sided. Results: The peak onset age of patients with ER+/PR+ tumors and ER+/PR- tumors was 50, and it was significantly higher than that of patients with ER- tumors, which is 48(P=0.001). Univariate analysis showed that ER+/PR- tumors were larger in size, had more lymph nodes of metastasis, were higher in tumor grade than ER+/PR+ tumors. Furthermore, the expression of ER and CathepsinD was significantly lower, and CerbB-2 expression was higher in ER+/PR- tumors than in ER+/PR+ tumors. Multivariate analysis indicated that positive PR expression was associated with the level of ER(OR=1.792, P=0.000), CathepsinD(OR=1.380, P=0.035)and CerbB-2(OR=0.639, P=0.007). DFS(P=0.004) and OS(P=0.009) were higher among patients with PR-expressing tumors than with PR- negative tumors. Conclusions: ER+/PR+ tumors and ER+/PR- tumors may have the same etiology which is different from that of ER- tumors. Because of low ER level and changes of the expression of CerbB-2 and CathepsinD, the tumors that lacked PR expression display more aggressive features and have worse prognosis. According to these differences, new target of therapy and endocrine regimen may provide the possibility of improving the response and prognosis of endocrine therapy for patients with ER+/PR- tumors.

No significant financial relationships to disclose.

The rule of mortality risk in young women (≤35 years) with primary breast cancer

21098

Background: The prognosis of young women (=35 years) is poorer than that of women over 35 years, which may indicate that they bear different biologic characteristics. However, such data is still not available at home and abroad as the rule of mortality risk in young women and its distinction from that in women over 35 years. We sought to investigate the clinical characteristics, prognosis and the rule of mortality risk in young women (=35 years) with primary breast cancer. Methods: We performed a retrospective study of 2331 female unilateral breast cancer patients undergoing surgery in our hospital from January 1990 to October 2005.They were divided into two groups with the cut-off of 35 years. Selection criteria included complete data on the following: age, tumor size, axillary nodal status, estrogen receptor (ER) status, menopausal status.Overall survival curve was estimated by Kaplan-Meier method and annual mortality hazard by hazard function. Their clinicopathologic indices, overall survival curve and annual mortality hazard were analyzed. Results: There was statistical significance between =35 years and >35 years group in terms of tumor size( P =0.0231), axillary nodal status( P <0.001) and estrogen receptor status( P =0.064). 10-year overall survival was 72% and 79% ( P = 0.0081), respectively, for =35 years and >35 years group. Although annual mortality hazard curve for both groups showed double-peaked pattern, there also exist some differences. Mortality surges for =35 years patients appeared earlier than those for >35 years counterparts. Moreover, =35 years group showed a minor increase between double peaks, which cannot be found in >35 years group. Conclusions: Between the two groups, different tumor biology leads to the discrepancy of overall survival and mortality pattern, which might indicate distinct principles and measures in the follow-up and treatment for young patients to provide the possibility of improving the therapeutic effect and reducing the mortality hazard.

No significant financial relationships to disclose.

An oil-degrading bacterium: Rhodococcus erythropolis strain 3C-9 and its biosurfactants

AIMS

To isolate a biosurfactant-producing bacterium and find new products within its culture.

METHODS AND RESULTS

A biosurfactant-producing bacterium identified as Rhodococcus erythropolis (3C-9 strain) was isolated from seaside soil. When n-hexadecane was supplied as the sole carbon source, two types of biosurfactants (free fatty acids and glycolipids) were detected in the supernatant of the bacterial culture by use of thin layer chromatography (TLC). Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the former consisted of at least 12 free fatty acids of chain lengths from C(9) to C(22); and the latter contained 2 kinds of glycolipids (a glucolipid and a trehalose lipid), which were detected by use of TLC, as well as GC-MS. The hydrophobic moieties of both glycolipids consisted of seven types of straight-chain fatty acids of varying compositions, with chain lengths ranging from C(10) to C(18). It was also noted that biosurfactants of strain 3C-9 were produced in a manner that was growth-related and cannot be synthesized from water-soluble substrates. The effects to enhance the solubility of polycyclic aromatic hydrocarbons and the degradation rate of hexadecane were also tested.

CONCLUSIONS

The biosurfactants produced by strain 3C-9 of R. erythropolis included two kinds of glycolipids, as well as free fatty acids. These biosurfactants were notably different from those of previously reported Rhodococcus species, both in terms of their structure and chemical composition.

SIGNIFICANCE AND IMPACT OF THE STUDY

Strain 3C-9 of R. erythropolis is a competitive candidate for use in oil spill cleanup operations, or in new biosurfactant exploration. The findings in this report show that Rhodococcus is a natural reservoir of new biosurfactants.