Emergence of a sylvatic enzootic formosan ferret badger-associated rabies in Taiwan and the geographical separation of two phylogenetic groups of rabies viruses

Taiwan had been declared rabies-free in humans and domestic animals for five decades until July 2013, when surprisingly, three Formosan ferret badgers (FB) were diagnosed with rabies. Since then, a variety of wild carnivores and other wildlife species have been found dead, neurologically ill, or exhibiting aggressive behaviors around the island. To determine the affected animal species, geographic areas, and environments, animal bodies were examined for rabies by direct fluorescent antibody test (FAT). The viral genomes from the brains of selected rabid animals were sequenced for the phylogeny of rabies viruses (RABV). Out of a total of 1016 wild carnivores, 276/831 (33.2%) Formosan FBs were FAT positive, with occasional biting incidents in 1 dog and suspected spillover in 1 house shrew. All other animals tested, including dogs, cats, bats, mice, house shrews, and squirrels, were rabies-negative. The rabies was badger-associated and confined to nine counties/cities in sylvatic environments. Phylogeny of nucleoprotein and glycoprotein genes from 59 Formosan FB-associated RABV revealed them to be clustered in two distinct groups, TWI and TWII, consistent with the geographic segregation into western and eastern Taiwan provided by the Central Mountain Range and into northern rabies-free and central-southern rabies-affected regions by a river bisecting western Taiwan. The unique features of geographic and genetic segregation, sylvatic enzooticity, and FB-association of RABV suggest a logical strategy for the control of rabies in this nation.

Drug-repositioning screening identified piperlongumine as a direct STAT3 inhibitor with potent activity against breast cancer

Signal transducer and activator of transcription (STAT) 3 regulates many cardinal features of cancer including cancer cell growth, apoptosis resistance, DNA damage response, metastasis, immune escape, tumor angiogenesis, the Warburg effect and oncogene addiction and has been validated as a drug target for cancer therapy. Several strategies have been used to identify agents that target Stat3 in breast cancer but none has yet entered into clinical use. We used a high-throughput fluorescence microscopy search strategy to identify compounds in a drug-repositioning library (Prestwick library) that block ligand-induced nuclear translocation of Stat3 and identified piperlongumine (PL), a natural product isolated from the fruit of the pepper Piper longum. PL inhibited Stat3 nuclear translocation, inhibited ligand-induced and constitutive Stat3 phosphorylation, and modulated expression of multiple Stat3-regulated genes. Surface plasmon resonance assay revealed that PL directly inhibited binding of Stat3 to its phosphotyrosyl peptide ligand. Phosphoprotein antibody array analysis revealed that PL does not modulate kinases known to activate Stat3 such as Janus kinases, Src kinase family members or receptor tyrosine kinases. PL inhibited anchorage-independent and anchorage-dependent growth of multiple breast cancer cell lines having increased pStat3 or total Stat3, and induced apoptosis. PL also inhibited mammosphere formation by tumor cells from patient-derived xenografts. PL's antitumorigenic function was causally linked to its Stat3-inhibitory effect. PL was non-toxic in mice up to a dose of 30 mg/kg/day for 14 days and caused regression of breast cancer cell line xenografts in nude mice. Thus, PL represents a promising new agent for rapid entry into the clinic for use in treating breast cancer, as well as other cancers in which Stat3 has a role.

Microdecompression in spinal stenosis: a review

A goal of surgical treatment is to effectively treat pathology with minimizing injury of normal tissue. Microdecompression techniques are traditionally defined as procedures performed with a small incision using magnification and minimization of destruction to non-pathologic tissues. The good candidates are patients diagnosed of spinal stenosis who fail an appropriate course of non-operative management. These patients should have radiographic evidence of localized spinal stenosis without associated structural instability. Various techniques of microdecompression have been introduced until now. Although more technically challenging, microdecompression have produced long-lasting favorable outcomes via proper patient selection and surgeon training. In addition, the minimally invasive access techniques can greaten the results of microdecompression in the acute postoperative period. Through advanced minimally invasive techniques, the microdecompression will evolve in the future for sure.

Abstract PD1-2: PIK3CA mutations and/or low PTEN predict resistance to combined anti-HER2 therapy with lapatinib and trastuzumab and without chemotherapy in TBCRC006, a neoadjuvant trial of HER2-positive breast cancer patients

We have recently reported that in patients with HER2-positive breast cancer, neoadjuvant targeted therapy with lapatinib and trastuzumab to more completely block the HER receptor layer, combined with endocrine therapy (in ER-positive tumors) and without chemotherapy led to a substantial 27% pathologic complete response (pCR) rate in the breast. Activation of downstream signaling pathways may lead to resistance to therapies targeting the HER pathway receptors. Aberrant activation of the PI3K pathway via decreased levels of PTEN and/or the presence of activating PIK3CA mutations has been implicated in resistance to targeted anti-HER2 therapy, but results of clinical trials are all confounded by the co-administration of chemotherapy and are inconsistent. We sought to clarify the role of these variables in predicting pCR, a surrogate for long-term outcome, in patients treated with potent targeted therapy alone in a prospective Phase II neoadjuvant trial in patients with HER2-positive breast cancer.

Patients with large tumors (median 6 cm) were given 12 weeks of lapatinib plus trastuzumab followed by surgery (Rimawi et al. JCO, 2013). Serial tissue biopsies were obtained from study participants. For this study, we focused on baseline pre-treatment characteristics. PTEN protein levels were measured by IHC and scored using the H-score. PIK3CA mutations were identified on extracted DNA using multiplex PCR with targeted next generation sequencing (the Ion Torrent 50-gene cancer mutation panel).

Of 64 evaluable patients, tissue was available on 59 for PTEN IHC, and sufficient DNA was available on 33 for the mutation panel. PTEN median H-score was 100 (range 0-300). PTEN status when dichotomized by the median was correlated with pCR (32% in high PTEN vs. 9% in low PTEN, p = 0.04). Activating PIK3CA mutations were identified in 12 out of 33 tumors (36%; 3 mutations in the helical and 9 in the catalytic domain) and were independent of ER status. None of the patients whose tumors harbored a PIK3CA mutation achieved pCR (p = 0.06). There was no association between PTEN status and PIK3CA mutation suggesting they are independent variables (p = 0.44). When PIK3CA mutations were considered together with PTEN status, there were 31 cases with data on both. The overall pCR rate in this cohort was 16% (lower than pCR rate observed in the overall trial). However, 0/17 cases (0%) with a mutation and/or PTEN low expression (<100 H score) had a pCR compared to 5/14 cases (36%) with PI3KCA wild type and high PTEN levels (p = 0.01).

We conclude that PI3K pathway activation downstream of HER2 as a result of either low PTEN or activating PIK3CA mutation results in resistance to the combination of lapatinib and trastuzumab. This is the first report on patient tissue samples from a neoadjuvant trial using the combination of lapatinib and trastuzumab without chemotherapy. If validated in a larger cohort, our findings suggest that patients with HER2 positive tumors and who also harbor aberrant downstream PI3K pathway activation may benefit from the addition of PI3K/Akt/mTOR inhibitors to potent HER2 blockade.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD1-2.

Abstract P4-06-01: Expression and DNA copy number profiling suggest novel therapeutic approaches for triple negative breast cancer subtypes

The aggressive triple negative breast cancers (TNBCs), which lack ER, PR and HER2, comprise a high-risk subset of human breast cancers which remain poorly characterized and lack effective treatments. While recent meta-analyses indicate the complexity of these tumors, no robust independently validated phenotypes have been defined. We have identified four distinct molecular subtypes through independent non-negative matrix factorization of expression data from 84 Discovery and 114 Validation Set TNBCs profiled at a single institution, with matching CNV data (SNP array). We then classified 485 publically available TNBCs via a centroid signature of only 80 genes. All three sets supported stratification of tumors by cell cycle, DNA repair, and immunological signaling pathways that have significantly different clinical outcomes. The first subtype, composed of intermediate grade tumors, resembles the “Molecular Apocrine” or “Luminal AR” subtype described previously and was defined by enrichment of prolactin, aryl hydrocarbon receptor, and ERBB4 signaling with activated downstream expression patterns of ESR1 signaling. Large deletions of chromosome 6 were specific to this subtype. While focal deletions at 14q21.2 and 12q13.13 were present in >60% of tumors of the other subtypes, the genes at these loci (FOXA1 and ERBB3) were overexpressed in the first subtype. Inhibitors of AR and MUC1, both overexpressed, may prove effective for these tumors. A second subtype defined as “Claudin-Low” or “Mesenchymal Stem-Like” showed overexpression of markers of mesenchymal lineage (ADIPOQ and OGN). Targets responsive to beta-blockers (ADRB2), and targetable molecules associated with platelet and endothelial function (EDNRB, PLA2G2A, PTGER3/4, PTGFR, PTGFRA) were also upregulated. Two basal-like subtypes were found with significant differences in DFS and OS, even after correction for available clinical covariates. The high-risk (31% 5-year DFS), low immune function subtype was regulated by SOX 10, 8, and 6 and had unique copy-number driven expression of FGFR2. The second, low-risk (78% 5-year DFS) basal-like subtype was enriched for overexpression of many immune pathways, regulated by increased STAT1 and activated STAT downstream signaling, as well as exclusive upregulation of CTLA4. This subtype also had the lowest tumor cell fraction as calculated by allele specific copy number analysis of tumors (ASCAT). Both basal-like subtypes expressed TTK, CHEK1, TOP2A, and AURKA. CDK1 was correlated with copy number variation at 10q21.1. We proposed and validated four molecular subtypes of TNBC before applying the resulting gene signature to 7 external expression sets. The described subtypes vary by clinical behavior and inferred biology. Each subtype appears to have specific gene expression regulated by copy number variation and a set of genes targetable by currently available agents. These findings further define the heterogeneity of TNBCs and suggest potential therapeutic targets for each subtype.

This work was supported by a Promise grant from the Susan G. Komen for the Cure Foundation (KG081694).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-06-01.

Abstract P5-03-12: Targeting breast cancer stem cells using the autopahgy inhibitor N-Acetyl cysteine

Introduction: One in eight women is diagnosed with breast cancer in the United States. The most aggressive form of breast cancer is the “triple negative breast cancer” (TNBCs), where there is a lack of expression of all three receptors, namely ER, PR and HER2 and a lack of targeted therapies lead to the highest relapse rate in breast cancer. This makes it imperative to identify and target the mechanism of relapse of this cancer. We have recently identified autophagy as a mechanism of tumor resistant cell survival in breast cancer. We have demonstrated an increase in autophagy in chemotherapy treated patients. Further, we have shown that addition of a stem cell inhibitor against NOTCH reduces autophagy and stem cells population. In order to eliminate these tumor resistant cells from surviving chemotherapy, we plan to target the cell survival pathway of autophagy using N-acetyl csyteine as a novel inhibitor.

Materials and Methods: We treated three triple negative cell lines (SUM159, BT549 and MDA-MB231) with varying concentrations of N-acetyl cysteine and determined its impact on tumor initiating cells via mammosphere formation and FACS sorting of CD44hi/CD24low cells. N-acetyl cysteine affects mitochondrial metabolism so we tested its impact on mitochondrial DNA mass.

Results: N-acetyl cysteine significantly decreased TIC population as evidenced by the remarkable reduction in mammosphere formation efficiency and levels of CD44hi/24low cells at 1 and 10uM in all three cell lines. In two cells lines we have demonstrated that there is a significant increase in mitochondrial mass upon treatment of NAC.

Conclusion: We have currently determined that N-acetyl cysteine works via autophagy and eliminates tumor initiating cell population. We have also demonstrated that this involves changing the mitochondrial mass and overall changes in the metabolism of these cells. This novel interlink between mitochondrial metabolism and autophagy provided a new insight into the role of tumor initiating cells in breast cancer and possible new approaches to treat therapy resistance in triple negative breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-12.

Abstract P5-03-03: Antitumor Activity and Cancer Stem Cells Effect of Cetuximab in Combination with Ixabepilone in Triple Negative Breast Cancers (TNBC)

Purpose: The ErbB family, including EGFR, has been demonstrated to play key roles in metastasis, tumorigenesis, cell proliferation, and drug resistance. Recently, these characteristics have been linked to a small subpopulation of cells classified as cancer stem cells (CSCs) which are believed to be responsible for tumor initiation and maintenance. Ixabepilone is the microtubule-stabilizing agent has been expected to be more sensitive than the conventional taxanes. The aim of this study was to investigate whether the EGFR monoclonocal antibody cetuximab, in combination with ixabepilone is a more effective treatment, and kill cancer stem cells more effectively as compared to chemotherapy alone in TNBC.

Experimental Design and Results: Breast CSC populations were evaluated with FACS analysis (CD44+ and CD24−/low, or Aldefluor+) and mammosphere formation efficiency (MSFE). In vitro, we demonstrated that in triple negative cell lines (MDA-MB-231 and SUM159), cancer stem cell populations were decreased after treatment of cetuximab, or cetuximab plus ixabepilone. In vivo, cetuximab in combination with ixabepilone treatment caused significant tumor regression (cetuximab vs. cetuximab+ ixabepilone; tumor volume fold change P <0.05 (MDA-MB-231), P <0.0001 (SUM159) in triple negative breast cancer xenografts. Thus, cetuximab decreased CSC population in xenograft tumors. Decrease in autophagy (LC3b, p62 and autophagosomes) were seen in cetuximab-treated tumors.

Conclusions: These studies demonstrate that cetuximab in combination with ixabepilone is more effective than chemotherapy alone in TNBC by affecting CSCs, as well as bulk tumor. These data support a neoadjuvant phase II study comparing ixabepilone vs. ixabepilone +cetuximab in TNBC patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-03.

Abstract S5-8: Parallel upregulation of Bcl2 and estrogen receptor (ER) expression in HER2+ breast cancer patients treated with neoadjuvant lapatinib

Background: We previously showed in HER2+ models of breast cancer (BC) that potent inhibition of the HER receptor layer can lead to re-expression of estrogen receptor (ER) or activation of the ER pathway. Consequently, the anti-apoptotic ER gene product Bcl2 is upregulated, resulting in enhanced tumor cell survival and treatment resistance. In this study, we investigated whether Bcl2 and ER expression levels are simultaneously increased by neoadjuvant treatment with the dual HER1/2 tyrosine kinase inhibitor lapatinib in HER2+ BC patients.

Methods: In a neoadjuvant phase II clinical trial 49 HER2+ BC patients were treated with lapatinib as a single agent for 6 weeks, followed by trastuzumab/docetaxel for 12 weeks before surgery. Tumor specimens were prospectively collected at different time-points during lapatinib treatment (baseline, and weeks 2 and 4). Bcl2, ER, progesterone receptor (PR), total (t) and phosphorylated (p)-HER2, and Ki67 were assessed by immunohistochemistry. Spearman correlation was used to evaluate the association among the biomarkers at baseline, and the correlation of their changes over time. Fisher's Exact test and non-parametric Wilcoxon rank sum test were used respectively to determine if the frequency and the magnitude of Bcl2 expression changes were associated with baseline ER status.

Results: 35/49 HER2+ tumor specimens (71%) were available for baseline evaluation of Bcl2 and ER. Of those, 12 (34%) were ER-positive (Allred score ≥ 3) and 23 (66%) ER-negative. Baseline Bcl2 expression correlated positively with ER (r = .75; p < .0001) and PR (r = .53; p = .0015), and inversely with t-HER2 (r = −.43; p = .0097). ER baseline expression correlated positively with PR (r = .57; p = .0004), and inversely with t and p-HER2 (r = −.55; p = .0005, and r = −.37; p = .0282, respectively) and Ki67 (r = −.39; p = .0271). Bcl2 changes at week 2 (w2) positively correlated with changes in both ER and PR levels (r = .70; p = .0002 and r = .57; p = .0076, respectively). Additionally, the increase in Bcl2 expression, observed in 9 of the 23 (39%) tumors with tissue available at w2, was significantly more frequent (p = .0147) and of greater magnitude (p = .0001) in ER-pos vs. ER-neg tumors — 8/9 ER-pos tumors at w2 (including 3 converted from ER-neg by lapatinib) had increased Bcl2, while only 1 of the 14 (7%) ER-neg tumors (at baseline and w2) had increased Bcl2. The expression of ER itself at w2 also increased in 3 out of the 6 (50%) tumors which were originally ER-pos and had tissue available at w2, and in all of them Bcl2 increased in parallel. Of note, the single baseline ER-pos tumor that showed a reduction in ER at w2 had a parallel decrease in Bcl2. Similar observations or trends were found at week 4.

Conclusion: Our study suggests that Bcl2 is upregulated as a result of enhanced/restored ER activity upon anti-HER2 therapy with lapatinib in HER2+ tumors. This further supports the use of endocrine along with anti-HER-2 therapy to block this escape pathway which could otherwise cause treatment resistance. In addition, the ER re-expression with lapatinib treatment observed in this study emphasizes the need to re-biopsy HER2+/ER− patients receiving anti-HER2 therapy and to add endocrine therapy if the tumor becomes ER-positive.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S5-8.

Abstract P6-07-11: Is the prognosis of lymphotropic invasive micropapillary carcinoma worse than invasive ductal carcinoma?: A population-based study of 645 patients

Purpose: Invasive micropapillary carcinoma (IMPC) is an uncommon distinct variant of breast carcinoma and is associated with an increased risk for regional lymph node metastases. Therefore, IMPC is considered to have an unfavorable prognosis when compared to invasive ductal carcinoma (IDC). The prognostic factors for IMPC are not well characterized due to the relative scarcity of cases reported in the literature.

Methods: We analyzed the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database to evaluate prognostic factors of a population of 645 breast IMPC patients and 300,060 breast IDC patients reported between 2001 and 2008. Using univariate and multivariate analyses, hazard ratios (HR) were calculated for disease-specific (DSS) and overall survival (OS) for these patients using parameters such as patient age at diagnosis, histological grade, ER status, PR status, tumor size, and degree of lymph node positivity. Subset analysis of high grade, lymph node-positive patients was performed to compare DSS and OS between IMPC and IDC.

Results: The 5-year DSS and OS for IMPC patients were 92.1% and 84.6% compared to 5-year DSS and OS of 88.5% and 80.2% for IDC patients. At presentation, TNM staging of IMPC cases was similar to IDC except for a higher percentage of LN metastases (52.4% in IMPC vs. 34.7% in IDC). Of those with known estrogen receptor (ER) status, 84.2% of IMPC cases were ER-positive, which was associated with better DSS (Hazard Ratio (HR) 0.36, p < 0.002) and OS (HR 0.62, p = 0.072). Patients with four or more positive lymph nodes had worse DSS (HR 7.1, p < 0.0001) and OS (HR 3.2, p < 0.0001) than node-negative patients, but those with one to three positive lymph nodes had similar DSS (HR 1.04, p = 0.96) and OS (HR 0.99, p = 0.97) as node-negative patients. In the subset of patients with high grade, node-positive breast carcinoma, patients with micropapillary histology had better DSS (p < 0.03) and a trend towards better OS (p = 0.12) than high grade, node-positive invasive ductal carcinoma. This subset of IMPC patients also had a higher percentage of ER-positive tumors (77%) compared to IDC patients (56%).

Conclusions: While IMPC has a high propensity for lymph node metastasis, it has a disease-specific and overall prognosis that compares favorably to IDC. The higher percentage of hormone-receptor positivity may account for this survival advantage, even in high grade, node-positive disease. Therefore, estrogen-receptor-negativity or having four or more positive lymph nodes at presentation may potentially serve as prognostic markers for IMPC patients. In this study population, patients with one to three positive lymph nodes have DSS and OS similar to node-negative patients. Additional clinical studies are warranted to further investigate this observation. This is the largest study of IMPC to date, and these findings help our understanding of this uncommon histological variant of breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-07-11.

Abstract P6-11-12: Nanoparticle-enhanced chemotherapeutics delivery in drug-resistant triple-negative breast cancer

Chemotherapeutics delivery is generally poor in tumors characterized by rapid perfusion and low blood volume fraction. Systemically administered nanoparticles can be engineered to overcome abnormal flow conditions to act as intravascular drug depots for the localized delivery of high concentrations of chemotherapeutics. The feasibility of this approach was first demonstrated using melanoma, and is now being further investigated using well-characterized human triple-negative breast cancer biopsies implanted into mice. Intravital microscopy studies of human cancer-in-mice selected for differing vascular morphologies have yielded intriguing preliminary data regarding the role of tumor vascularity in drug and particle delivery. The first-pass perfusion of a 40kDa dextran tracer revealed that BCM-2665 tumors are perfused ∼6x more rapidly than BCM-4195 tumors (11.3 ± 2.3s vs. 67.6 ± 11.0) and contain ∼30% lower volume fraction of blood (0.046 ± 0.011 vs. 0.062 ± 0.015). Interestingly, flow parameters that adversely impact drug accumulation appear to favor plateloid particle accumulation. BCM-2665 xenografts receiving an i.v. injection of 1000×400 nm particles show ∼10x more particle accumulation than BCM-4195 tumors (24.8 ± 3.2 × 103/mm3 vs. 3.5 ± 0.4 × 103/mm3). The ability of these therapeutic particles to reach tumors appears to be primarily driven by flow-related parameters, which we characterize using a combination of intravital microscopy, computed tomography, and mathematical modeling. The total number of particles accumulated within a given tumor appears to be largely driven by the number of particles entering the tumor, since ∼65–70% of entering plateloid particles are retained by the tumor vasculature. This suggests that cytotoxic intravascular drug depots may be a promising strategy for increasing the efficiency of chemotherapeutics delivery to drug-resistant tumors and is the premise of ongoing therapeutic response studies. Clearly if more drugs can be delivered to the tumors, better outcomes can be expected for the patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-11-12.

Abstract P3-06-14: Identification of Prognosis-Relevant Subgroups in Patients with Chemoresistant Triple Negative Breast Cancer

Purpose: Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. TNBC patients with pathologic complete response (pCR) have excellent survival, but those with residual disease after neoadjuvant chemotherapy have significantly worse outcome. However, some patients having extensive residual cancer burden after neoadjuvant chemotherapy do not relapse, and we hypothesize that there may be subgroups with diverse prognosis among these chemoresistant TNBC patients.

Methods: Forty-nine cases with residual cancer from 111 TNBC patients treated with neoadjuvant chemotherapy (in M.D. Anderson Cancer Center, 2000–2006) constituted the discovery cohort. Twenty-five chemoresistant samples from 47 neoadjuvant chemotherapy-treated TNBC (in Baylor College of Medicine and Methodist Hospital, 2002–2006) were chosen for validation. Extended validation was performed in 269 operable TNBC predicted to be chemoresistant (using a JAMA-published genomic predictor) from public databases.

Results: By comparing the gene expression data from cases in relapse with those from un-relapsed cases, we established a 7-gene prognostic signature (including AR, ESR2, GATA3, GBX2, KRT16, MMP28, and WNT11) using dChip and gene enrichment analyses. In the discovery cohort, the signature showed positive predictive value (PPV; i.e., cumulative relapse rate of patients predicted to relapse in 3 years) of 95.4% and negative predictive values (NPV; i.e., relapse-free survival of patients predicted not to relapse in 3 years) of 100%. In the validation cohort, the classifier predicted correctly with PPV of 75.0% and NPV of 76.9% at 3 years. Compared with patients predicted not to relapse, those predicted to relapse had a hazard ratio of 3.37 (95% CI, 1.15–9.85) for disease recurrence or death in 3 years. In an extended validation cohort of 269 patients, our signature discriminated chemoresistant TNBC in overall cohort (PPV, 52.4%; NPV, 77.7%; log rank P < 0.0001), or each subset (e.g., log rank p = 0.001 for Rotterdam set; p = 0.013 for Frankfurt set), with adjusted overall hazard ratio of 2.07 (95% CI, 1.26–3.39). This signature was the only marker that could effectively predict the relapse in patients with chemoresistant TNBC. Of note, the subgroup predicted not to relapse was characterized by high expression of luminal-like genes (AR, GATA3), while the subgroup predicted to have high possibility of relapse was characterized by high expression of cancer stem cell and epithelial-to-mesenchymal transition associated genes (WNT11, MMP28). The former corresponded to the luminal AR subtype and the latter to the mesenchymal stem-like subtype, according to Pietenpol's TNBC subtype classification.

Conclusion: We developed a clinically useful prognostic signature for chemoresistant TNBC. For these chemoresistant TNBC patients, new therapeutic strategies targeting AR-activation or cancer stem cells need to be developed.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-14.

Abstract OT3-3-01: Eniluracil + 5-fluorouracil + leucovorin (EFL) vs. capecitabine phase 2 trial for metastatic breast cancer

Based on a modified dosing protocol designed to optimize efficacy, an open-label EFL vs. capecitabine (4:3 randomization) Phase 2 trial for metastatic breast cancer is in progress. Eniluracil inactivates dihydropyrimidine dehydrogenase, thereby preventing the formation of α-fluoro-β-alanine, and conferring 100% oral bioavailability and a 5 hr half-life on 5-fluorouracil (5-FU). Study drugs are administered orally for 1st- or 2nd-line treatment for metastatic disease in patients previously treated with an anthracycline and a taxane. Arm 1: eniluracil (40 mg) taken 11–16 hr before 5-FU (30 mg/m2); leucovorin (30 mg) taken with 5-FU and the next day. The regimen is administered once/week for 3 weeks/4 weeks. Arm 2: capecitabine (1000 mg/m2) taken bid for 14 days/21days. Arm 2 patients with disease progression could crossover to take EFL in Arm X. Two sites in the USA and 19 in Russia are enrolling. Currently, 115 patients (21% are 1st-line, 70% had previous 5-FU treatment) are enrolled and 83 have had tumor assessments. EFL was well tolerated with no unexpected toxicities. As of May 2012, there were 11, 7, & 1 partial responses in Arms 1, 2, & X, respectively. The primary endpoint, progression-free survival, will be determined approximately 7.5 months after the trial is enrolled with 140 evaluable patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT3-3-01.

Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth's crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (M(w)) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake's rupture front quickens dynamic weakening by intense wear of the fault zone.

P3-16-02: Targeting Tumor Initiating Cells with siRNA/Nanotherapy in Triple Negative Breast Cancer

Residual human breast tumor cells after conventional therapies are enriched in tumor-initiating cells (TIC) characterized by CD44+/ CD24-/low/lineage- with self-renewal capacities. Our gene expression analyses in those cells and in breast cancer cells propagated as mammospheres (MSs) reveal an epithelial-mesenchymal-transition (EMT) signature (400 genes) mainly found in claudin-low molecular subtype human breast tumors. We performed lentiviral shRNA knockdown of that signature in MS. Critical shRNAs were found to decrease the TIC subpopulation. Among those genes, we found STAT3 (signal transducer and activator of transcription 3), NTN4 (netrin 4), and RPL39L (ribosomal protein L39-like). Here, we used a multiscale siRNA delivery system targeting those three genes in order to clarify the effect of silencing those genes over the self-renewal capacity on MSs with claudin-low features. To this end, duplex small interfering RNA (siRNA) against STAT3, NTN4, RPL39L, and scrambled siRNA as control, were introduced into neutral nanoliposomes (dioleoyl phosphatidylcholine, DOPC), and using mesoporous microscale biodegradable silicon particles as carriers. This multistage siRNA delivery system has been reported as a good approach for sustained gene silencing. Claudin-low-like human breast cancer cell lines (SUM159 and BT549) were plated in 24-well ultralow attachment plates with mammary epithelial growth medium (MEGM) (5,000 cells/well). Both cell lines were then treated with 1μg/well/6 wells of silicon particles loaded with DOPC nanoliposomes/siRNA. The primary MSs were allowed to grow for 3 days. MFs were counted by day 3 with a GelCount colony counter (Oxford Optronix, Oxford, UK). Mammosphere-Forming Efficiency (MSFE) was calculated by dividing the number of MSs by the number of seeded cells. In addition, established MSs were serially passaged by dissociation, and single cells were replated on fresh 24-well ultra-low attachment plates to form secondary mammospheres, which were counted after 3 days. One-way ANOVA and Tukey test were performed. A p value less than 0.05 was considered as significant. Our results show that silencing STAT3, NTN4, and RPL39L significantly reduces the MSFE in both primary (1%, 0.9%, and 1.7% respectively) (Figure 1) and secondary MSs (0.49%, 0.51%, and 0.45% respectively) (Figure 2) when compared to the scrambled control (2.4% and 1 % respectively) in BT549 cells. For SUM159 cells, we did not find any change in primary MSs for STAT3 (2.2%) and NTN4 (2.1%), even we found a higher percentage of MSFE in those cells treated with RPL39L siRNA (3.9%) when compared to the scrambled control (2.1%) (Figure 3). Nevertheless, a lesser MSFE were observed in those cells treated with STAT3 (0.9%, not significant), NTN4 (0.8%) and RPL39L (0.78%) in comparison to control (1.1%) (Figure 4). In conclusion, knocking-down of EMT-related genes (STAT3, NTN4, and RPL39L) decreases significantly the self-renewal capacity in mammospheres derived from claudin-low-like human breast tumor cells, being BT549 cells more sensitive than SUM159 cells to that silencing with siRNA loaded in DOPC nanoliposomes into silicon particles as carriers.

Acknowledgments: We thank Fundacion Alfonso Martin Escudero for the personal support of Dr. Sergio Granados-Principal.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-16-02.

P5-21-01: A Renewable Tissue Resource of Phenotypically Stable Human Breast Cancer Xenografts for Preclinical Studies

Introduction Translational breast cancer research is hampered severely by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that accurately reflect patient tumor biology. These limitations are due, in part, to the fact that traditional immunocompromised mouse models are not generally permissive for growth. We sought to circumvent some of these limitations by transplanting and growing human mammary tumors in the mammary fat pad of SCID/Beige immunocompromised mice in the absence of exogenous human fibroblasts.

Aims and Methods To establish a set of stable human breast cancer xenografts for preclinical studies. Human breast cancer biopsies were received, minced into small fragments and then transplanted directly into “cleared” fat pads of recipient SCID/Beige immunocompromised mice. Transplanted fat pads were checked weekly. After initial tumor was palpated and harvested, tumor fragments were transplanted into new SCID/Beige hosts for subsequent transplant generations. Serial immunohistochemical evaluations were performed to confirm human origin and biomarker status. Analytical flow cytometry for evaluating expression of proposed “cancer stem cell” markers, and gene and protein expression analysis were carried out on all stable lines.

Results and Conclusions Xenograft lines were established directly from breast cancer patient samples, without intervening culture in vitro, using the epithelium-free mammary fat pad as the transplantation site. Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet without exogenous human fibroblasts. Thirty six stably transplantable xenograft lines representing 27 patients were established, using pre-treatment, mid-treatment, and/or post-treatment samples. Most patients yielding xenografts were “triple-negative” (ER-PR-HER2−) (n=21), we were able to establish lines from three ER-PR-HER2+ patients, one ER+PR+HER2−, one ER+PR-HER2−and one “triple-positive” (ER+PR+HER2+) patients. Serially passaged xenografts show phenotypic consistency with the tumor of origin at the histopathology level, and remarkable stability across multiple transplant generations at both the genomic, transcriptomic, and proteomic levels. Of 27 lines evaluated fully, thirteen xenografts showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource, and should prove useful for preclinical evaluation of experimental therapeutics.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-21-01.

P1-04-09: Biphasic Effects of Docetaxel and Hedgehog Signaling Antagonists on Breast Cancer Tumor-Initiating Cells In Vivo

Recent data suggest the existence of a subset of breast cancer cells variously termed cancer stem cells, tumor-initiating, or tumor-propagating cells, that are capable of self-renewal and of regenerating tumors upon transplantation that are biologically consistent with the tumor of origin. These cells appear to be intrinsically resistant to systemic chemo- and radiation therapies and may therefore be responsible for treatment resistance, and disease recurrence. Several signal transduction networks have been implicated in normal and malignant stem cell self-renewal. These include those of the Hedgehog, Notch, Wnt, EGF, FGF families of ligands. Antagonists of these networks have become attractive targeted therapeutic agents. In this study, we evaluated two different Hedgehog signaling antagonists, one targeting Smoothened (the main membrane effector of activated signaling) and one targeting GLI1/2 (the two transcription factors mediating ligand response), for their ability to shrink patient-derived xenograft tumors and to affect the number or function of breast tumor-initiating cells in vivo. Both antagonists showed little effect as single agents, but could augment tumor shrinkage by docetaxel. However, these effects were only observed in those models showing evidence of canonical SMO/GLI-mediated signaling. In dilutional transplantation assays, both SMO or GLI targeted agents have a biphasic effect on the behavior of the tumor-initiating population such that large cell numbers yielded few tumors while intermediate cell numbers yielded tumors at a comparable rate as controls. These data suggest that combination therapy alters the functional state of stem cells in the context of larger cell numbers rather than targeting the tumor-initiating cell directly. These data therefore have significant relevance for the interpretation of ongoing clinical trials of hedgehog signaling inhibitors in solid tumors, including breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-04-09.

P3-14-09: A Phase II Preoperative Study of Dasatinib, a Multi-Targeted Tyrosine Kinase Inhibitor, in Locally Advanced “Triple-Negative” Breast Cancer Patients

Background: We previously reported that kinases (Src, Yes-1, cKIT, Abl, and EPH4) were druggable in triple negative breast cancer (TNBC). In this clinical trial, we sought to translate these findings by treating TNBC patients with dasatinib, a multi-targeted kinase inhibitor against these targets.

Methods: Women with stage II-III TNBC were eligible. Patients received dasatinib at 100 mg daily for 3 to 4 weeks before standard-of-care definitive surgery and chemotherapy. Biopsies were performed at baseline, week 1, and at the time of surgery. A cohort of patients had positron emission mammography (PEM; baseline and at 2–3 weeks of dasatinib therapy). This study was designed to detect an increase in clinical response rate from 10% to 25%, using a Simon optimal two stage design, with one-sided alpha=5% and power=80%. At least 3 responses out of 22 patients were needed to proceed to the second stage.

Results: 22 patients were enrolled (Table 1). Median tumor size was 7.0 cm (range 2.4-25 cm). Adverse events were modest, mainly grade 1–2 (headache: 45%, abnormal LFTs: 55%, GI: 23%, fatigue: 18%). One patient had a myocardial infarction 24 hours after starting dasatinib. Out of 22 patients, 2 (9%) had a clinical partial response after 3–4 weeks of therapy, 15 had stable disease (68%), while 5 had progressive disease (23%). Of the 8 patients who received paired PEM imaging, metabolic responses were observed in 2 patients (25%). Conclusion: A short course of dasatinib led to clinical responses in 2 out of 22 patients with TNBC, and the study did not proceed to second stage. Since TNBC is a heterogeneous disease, biomarker studies including sequencing of candidate genes like B-RAF for inactivating mutations might enable selection of those TNBC patients who could benefit from dasatinib.

P1-03-02: The Norton-Simon Hypothesis and Cancer Stem Cells: How Cancer Stem Cells May Explain the Effectiveness of Dose-Dense Chemotherapy

Background: Systemic therapies are effective initially in controlling and reversing tumor growth; however, residual cancers will invariably re-grow despite this initial response. We have published data from paired human breast cancer samples that standard therapy every three weeks kills dividing daughter cells but not tumor-initiating cells (TICs), so that samples obtained after therapy are enriched for CD44+/CD24−/low putative “tumor-initiating” or “cancer stem” cells, indicating that standard treatment regimens are missing the critical targets, TICs. Interestingly, we have recent data in human breast tumors that indicate that TICs may in fact be chemosensitive initially, with a decrease in TICs observed within two days of chemotherapy, but shortly thereafter, TICS are actually induced by chemotherapy.

Materials and Methods: To evaluate TICs response to chemotherapy, mice with human breast tumor xenograft lines BCM-2665a and BCM-2147 were treated with vehicle, 10-, or 33-mg/kg docetaxel, and then tumors were collected for TIC assays and molecular analysis at both 48 and 72h after treatment. Using Affymetrix gene expression microarrays and reverse phase protein array (RPPA) analysis with 119 different validated antibodies, we identified pathways involved in regulation of TICs. Results: According to flow cytometric analysis for TIC markers and mammosphere (MS) formation efficiency, BCM-2665 TICs were reduced by docetaxel treatment compared to vehicle-treated at 48h post 10 mg/kg docetaxel (4-fold decrease) and 48 and 72h post 33 mg/kg docetaxel compared to control (14- and 2-fold decrease, respectively). Although the BCM-2147 TICs did not significantly decrease at any time points or doses tested, they were clearly induced at 72h post-treatment compared to control. Additionally, BCM-2665 TICs were increased within 72h post 10 mg/kg docetaxel, indicating that these time points are ideal for defining the mechanisms responsible for induction of TICs. Ingenuity Pathway Analysis of Affymetrix microarray data for both BCM-2665 and BCM-2147 revealed induction of inflammatory pathways, suggesting leukocyte infiltration associated with induction of TICs. Furthermore, RPPA analysis confirmed gene expression changes from the microarray data, and implicated apoptosis and inflammatory pathways. Sixteen of 28 proteins significantly changed with activation of CSC are involved in development of leukocytes. Discussion: These findings are consistent with the Norton-Simon Hypothesis in that chemotherapy regimens given more frequently may in fact eliminate TICs, thereby explaining the proven increased effectiveness of dose-dense chemotherapy. Based on when TICs became chemoresistant, we are comparing dose-dense treatment (4 mg/kg docetaxel every 3 days) to a traditional single dose of 32 mg/kg, in an effort to eliminate the tumor cells that cause tumor recurrence. Furthermore, our analysis of gene expression at both the RNA and protein level implicated the immune cells as TICs inducers. Since our immunocompromised mice lack T- and B- cells but have active macrophages, macrophages are indicated as inducers of TICs. We are focusing our current efforts at identifying how immune cells activate TICs and thus enhance tumorigenesis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-03-02.

Abstract P6-15-03: Phase Ib Trial of the Gamma Secretase Inhibitor (GSI), MK-0752 Followed by Docetaxel in Locally Advanced or Metastatic Breast Cancer

Background: The cancer stem cell hypothesis asserts that there is a small population of cells within a tumor that has the ability to self renew and differentiate, and that these cells drive tumor growth and metastasis but are resistant to conventional cytotoxic chemotherapy. Pathways involved in stem cell growth and differentiation are viable targets for new anticancer therapies. One such pathway, Notch, is inhibited by GSIs which prevent translocation of Notch intracellular domain to the nucleus. Inhibition of GS concurrent with chemotherapy might improve disease control by targeting both stem cells and differentiated cells within the tumor. This Phase Ib clinical trial was designed to determine the MTD of the GSI, MK-0752, in combination with docetaxel, and to evaluate an effect on stem cell markers in serial tumor biopsies.

Methods: Eligible subjects had metastatic breast cancer or locally advanced breast cancer that did not respond to anthracycline therapy. Patients with disease that progressed on a taxane, or who had received a taxane within 6 months were excluded. MK-0752 was administered orally on days 1-3 of each 21-day cycle of therapy, in escalating doses. Dose levels (mg/day) 1=300; 2=450; 3=600; and 4=800. Docetaxel 80 mg/m2 IV was administered day 8, with pegfilgrastim day 9 each cycle. Treatment was continued until disease progression, unacceptable toxicity, or symptomatic deterioration. The trial was monitored using the Time to Event Continual Reassessment Method, targeting a 20% toxicity rate. Tumor biopsies were performed at baseline, after 1 cycle, and at treatment completion in a subset of patients.

Results: 30 patients were enrolled between Mar 2008 and Jan 2010. Dose limiting toxicities of the combination included diarrhea, hand-foot syndrome, and LFT elevation. 20/30 patients experienced Grade 1 or 2

fatigue. The final estimates and confidence intervals for the probability of dose limiting toxicity at each dose level are summarized in the table:

Probability = probability of dose-limiting toxicity 20 enrolled patients had measurable disease by RECIST criteria. Of these, 9 had PR, 8 SD, and 3 PD, for an estimated RR of 45% to the combination. 2 patients have been maintained on therapy in excess of 22 cycles. Conclusions: Dose level 3 was identified for further study in a Phase II randomized trial. Efficacy of docetaxel was not inhibited by MK-0752, as a 45% RR in patients with measurable disease was observed. There is intriguing long term disease stabilization in 2 patients. Evidence of an effect of the combination on the stem cell population was apparent on serial biopsies as presented at SABCS Dec 2009 (Abstract # 48); additional biopsy data will be presented.

Decreased TGFβ signaling and increased COX2 expression in high risk women with increased mammographic breast density

Abstract #1107

Background
 High mammographic density is associated with up to a 6-fold increased risk of breast cancer. Pathways responsible for this increased density are unknown. We hypothesize that specific molecular pathways exist that are associated with increased mammographic density and breast cancer risk, and may therefore be used to identify potential targets for chemoprevention.
 Methods
 Histologically confirmed normal breast tissue was collected from women undergoing breast surgery who had available demographic data and mammograms for review. Breast parenchymal density was classified according to the American College of Radiology's Breast Imaging – Reporting and Data System reporting system. Quantitative classification of mammographic parenchyma was performed using thresholding method and percent density. Women with low (less than 50%) versus high (greater than 50%) breast density were compared. Double-stranded cDNA was synthesized from the normal breast tissue using an oligo-dT primer containing a T7 RNA polymerase promoter, followed by in vitro transcription with biotinylated ribonucleotides. The labeled cRNA was hybridized to Affymetrix HG U133Plus2 chips which comprise ∼28,600 genes to determine gene expression patterns. Immunohistochemical analysis (IHC) of estrogen receptor, progesterone receptor, proliferation (Ki67) and COX2 expression was performed.
 Results
 Sixty-two women were identified, 26 (42%) had high, and 36 (58%) had low mammographic density. Neither age, menopausal nor hormone receptor status influenced the gene expression pattern. Seventy-three genes had differential expression between normal breast tissue with high and low mammographic density (p<0.001, fold change>1.5) and had a low false discovery rate (<10%). Of these 73 differentially expressed genes, network and canonical pathway analysis demonstrate decreased TGFβ signaling (TGFBR2, SOS, SMAD3 and CD44 expression) in dense breast relative to non-dense breast. By IHC, Ki67 (stroma) and COX2 expression were significantly higher in dense breasts (p<0.05) on univariate analysis, and only COX2 expression in the stroma was statistically significant at (p<0.01) on multivariate analysis.
 Conclusion
 TGFβ ligands are currently the only growth factors known to prevent mammary epithelial cell proliferation. TGFβ has been reported to influence COX-2 expression, and these molecules are highly differentially expressed in individuals at high risk of developing breast cancer. These results suggest that COX2 inhibition should be further investigated for breast cancer prevention despite possible increase in cardiovascular risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1107.

BRCA1 gene expression signature predicts for anthracycline-chemosensitivity in triple-negative breast cancer

Abstract #6039

Background: We used a previously published gene expression signature that can identify tumors from BRCA1 mutation carriers to evaluate its predictive value in triple-negative breast cancer as a marker for chemosensitivity to anthracycline-based chemotherapy. We proposed that based on preclinical evidence suggesting that BRCA1-deficient breast cancer cells are sensitive to DNA damaging drugs such as cisplatin and anthracyclines this gene expression profile may identify tumors with anthracycline chemosensitivity. Two previously published studies defined a gene expression signature associated with BRCA1 germline mutation.(1,2) In these studies, sporadic tumors were misclassified as BRCA1 tumors and further analysis revealed methylation of the BRCA1 promoter region and decreased BRCA1 gene expression. This finding suggests the possibility of identifying sporadic tumors with decreased BRCA1 activity.
 Methods: We selected from our database of a locally advanced breast cancer neoadjuvant trial all cases of triple negative breast cancer that received 4 cycles of doxorubicin/cyclophosphamide(AC, 60/200 mg/m2, every 3 weeks) prior to surgery. Pathologic response to chemotherapy was disappearance of all invasive cancer or microscopic residual disease. Tumoral gene expression profile previously obtained using Affymetrix U133A Chip was analyzed for an optimal set of 100 most differentially expressed genes distinguishing BRCA1 and sporadic triple negative tumors according to the previously identified gene signature by van't Veer et al.1 We performed unsupervised clustering to determine if this signature could classify a subtype of triple-negative tumors with "BRCAness" and to test our hypothesis that BRCA1-like tumors are more sensitive to AC. We then performed a supervised analysis to determine the most differentially expressed genes that could prospectively identify triple-negative sporadic tumors with “BRCAness” and tumors from BRCA1 germline carriers that are sensitive to anthracyclines.
 Results: Of the 66 patients enrolled in our neoadjuvant trial, 12 patient's tumors were triple negative and received preoperative AC. By unsupervised clustering, the gene expression pattern associated with BRCA1 cancers subdivided these sporadic cancers in to two groups: Group A(6/7 pathologic responders), and group B(5/5 non-pathologic responders). By supervised analysis, the most differentially overexpressed gene from the BRCA1 profile for AC sensitivity was YWHAH(14-3-3 eta polypeptide), while DKK3(Inhibitor of Wnt and Notch signaling pathway) and RPL23A were most overexpressed in all cases with adriamycin-resistance(p<0.01).
 Discussion: Triple negative sporadic breast cancer displaying “BRCAness” appear to be sensitive to AC chemotherapy. YWHAH, DKK3, and RPL23A are differentially expressed in anthracycline-sensitive versus resistant tumors. These three genes can potentially identify triple-negative breast cancers that exhibit “BRCAness” and sensitivity to DNA-damaging chemotherapy such as cisplatin, anthracycline, or PARP inhibitors.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6039.

Weak antiferromagnetic coupling for novel linear hexanuclear nickel(II) string complexes (Ni6 12+) and partial metal-metal bonds in their one-electron reduction products (Ni6 11+)

The preparation, crystal structures, magnetic properties and electrochemistry of novel linear hexanuclear nickel string complexes (Ni6(12+)) and their corresponding 1-e(-) reduction products (Ni6(11+)) are reported. In these complexes, the hexanickel chain is in a symmetrical arrangement (approximately D(4) symmetry) and is helically supported by four bpyany(2-) ligands [bpyany(2-) = the dianion of 2,7-bis(alpha-pyridylamino)-1,8-naphthyridine]. The Ni6(12+) complexes show that the two terminal nickel ions have high-spin states (S = 1) and the four inner ones have low-spin states (S = 0). The two terminal nickel ions exhibit weak antiferromagnetic coupling of ca.-5 cm(-1). All of Ni6(12+) complexes display three reversible redox couples at about -0.70, -0.20 and +1.10 V (vs. Ag/AgCl). The first reduction wave at about -0.20 V suggests facility of 1-e(-) reduction for the Ni(6)(12+) compounds. The reaction of Ni(6)(12+) complexes with hydrazine afforded the 1-e(-) reduction products (Ni6(11+)). As far as we are aware, the shortest bond distance of 2.202 A with a partial metal-metal bond was observed in Ni6(11+) compounds. The magnetic results of these Ni6(11+) compounds are in agreement with a localized model, in which the two terminal nickel ions are in a spin state of S = 1 whereas the central Ni3-Ni4 pair in a spin state of S = 1/2. The N6(11+) compounds show relatively strong antiferromagnetic coupling of about 60 cm(-1) between the terminal and the central dinickel ions.

Novel linear hexanuclear cobalt string complexes (Co6(12+)) and one-electron reduction products (Co6(11+)) supported by four bpyany2- ligands

The new ligand, 2,7-bis(alpha-pyridylamino)-1,8-naphthyridine (H2bpyany), was synthesized by the reaction of 2,7-dichloro-1,8-naphthyridine with 2-aminopyridine in the presence of t-BuOK under palladium(0)-catalyzed conditions. The preparation and characterization of novel hexacobalt string complexes, [Co6(mu6-bpyany)4(NCS)2](PF6)n (n=1 (1); n=2 (2)) and [Co6(mu6-bpyany)4(OTf)2](OTf)n (n = 2 (3); n = 1 (4)) are presented. The crystal structures for compounds have been determined by X-ray crystallography. Compounds 1 and 4 have the Co6 11+ configurations and are air-stable. Compounds 2 and 3 with Co6 12+ configurations are structurally similar to 1 and 4, respectively. The electrochemistry of 1 displays four redox couples at E1/2= -0.55, +0.38, +0.91, and +1.18 V (vs. Ag/AgCl). The magnetic data show that compounds 1 and 4 are in a spin state of S = 1/2, and 2 and 3 in a spin state of S = 1. The results of the EHMO calculations on compounds 1 and 2 are in agreement with their magnetic measurements.

Genomic approaches in the management and treatment of breast cancer

Breast cancer is the most common malignancy afflicting women from Western cultures. It has been estimated that approximately 211 000 women will be diagnosed with breast cancer in 2003 in the United States alone, and each year over 40 000 women will die of this disease. Developments in breast cancer molecular and cellular biology research have brought us closer to understanding the genetic basis of this disease. Unfortunately, this information has not yet been incorporated into the routine diagnosis and treatment of breast cancer in the clinic. Recent advancements in microarray technology hold the promise of further increasing our understanding of the complexity and heterogeneity of this disease, and providing new avenues for the prognostication and prediction of breast cancer outcomes. The most recent application of microarray genomic technologies to studying breast cancer will be the focus of this review.