P3-10-02: Gene Expression Changes in Methylnitrosourea (MNU)-Induced ER+ Mammary Cancers Following Short-Term Treatment of Rats with the Aromatase Inhibitor Vorozole

Aromatase inhibitors have proven to be highly effective in both therapy and prevention of ER+ breast cancer. Vorozole (R83842), a high affinity competitive inhibitor of aromatase (similar to letrozole and anastrozole) showed strong activity in early clinical trials against ER+ breast cancer. Furthermore, vorozole was highly effective in the prevention and therapy of ER+ cancers in the MNU-mammary cancer model (Lubet, et al., Carcinogenesis 19, 1345, 1998). In the present study, rats bearing mammary cancers induced by MNU were exposed to vorozole (1.25 mg/kg BW/day) for 5 days. Global gene expression analysis showed that 162 genes were down-regulated and 180 genes up-regulated in cancers treated with vorozole (p < 0.05 and fold change > 1.5). The genes modulated by vorozole were compared with two additional sets of data. First, thirty-two genes and a number of pathways exhibited significantly concordant changes with aromatase inhibitors both in the animal model and in at least three of four published human data sets. In particular, differentially expressed genes enriched in the cell cycle pathway that were related to chromosome condensation in prometaphase [including Aurora-A, Aurora-B, Bub1B, non-SMC condensin I complex, subunit H (BRRN1), Condensin, CAP-G, CAP-G/G2, CAP-H/H2, CAP-D2/D3, CAP-E, TOP2, Cyclin A, Cyclin B, CDK1, Histone H1 and inner centromere protein (INCENP)] were downregulated after treatment with the aromatase inhibitor. These results appear to be in agreement with the strong anti-proliferative effects of aromatase inhibitors in both animal and clinical studies. A second comparison was with an in vitro study in which estrogen was removed from MCF-7 cells in culture. Decreases in genes related to the E2F1 transcription factor were observed. In our study, 13 modulated genes exhibited E2F-1 binding sites in their promoter regions, and 7 genes contained both ER binding and E2F binding sites. We were able to confirm modulation of the cell cycle related and E2F-related genes in a large independent set of human samples treated with anastrozole. The results on RNA changes for Bub 1B, Cyclin A and CDK-1 were verified by employing IHC analysis. In summary, gene changes observed in the rat closely paralleled gene changes associated with aromatase treatment and estrogen withdrawal in humans.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-10-02.

P4-01-07: Combining Hedgehog Inhibitor, GDC-0449 with Tamoxifen Overcomes Tamoxifen-Resistance in In-Vitro and In-Vivo Studies of Estrogen-Receptor Positive Breast Cancer

Aims: Approximately 30–40% of patients with estrogen receptor positive (ER+) invasive breast cancer relapse despite targeted endocrine therapy with tamoxifen. Dependency of ER+ breast tumors shifts from estrogen to alternative cell survival mechanisms aberrantly activated over time facilitating drug-resistance and survival. We have identified Hedgehog (Hhg) signaling pathway as one such alternative pathway of survival activated in ER+ tumors that are resistant to tamoxifen. We sought to determine if treating such tumors with Hhg inhibitor and tamoxifen would improve outcomes.

Methods: Using MCF7 cell lines that are either sensitive (parental) or resistant to tamoxifen (4-hydroxy tamoxifen resistant-OHTR) and other ER+ cell lines, expression of Hhg markers (SHH, PTCH, SMO, GLI1, GLI2 and GLI3) and Hhg targets (SNAIL, MYC, BMI1 and FOXM1) was analyzed by Real-time RT-PCR, Western blotting and immunocytochemistry. GLI1 transactivation potential was measured using 8XGLI-Luciferase reporter plasmid. GLI1 was depleted in OHTR and T47D cells using GLI1siRNA. The GLI1 depleted cells were exposed to tamoxifen and assessed for i) cell viability by MTT assay, ii) extent of apoptosis by TUNEL assay and PARP/Caspase cleavage (Western blot), iii) cell cycle profile by flow cytometry and iv) presence of tumor initiating cells (TICs) by mammosphere formation assay. Effect of GDC-0449, a small molecule inhibitor of SMO was tested on OHTR cell induced xenografts in athymic nude mice by monitoring tumor growth and distant metastasis. Correlation of GLI1 expression in primary breast tumor tissues (assessed by immunohistochemistry) and disease-free interval was studied in women enrolled on an ongoing clinical trial (OSU 0483) in premenopausal women with ER+ breast cancer undergoing adjuvant oophorectomy and tamoxifen.

Results: Expression of Hhg signaling molecules and the targets are significantly activated in OHTR cells resistant to 0.5 and 1μM tamoxifen. Serial passage of the resistant cells in mice resulted in aggressive transformation of tumors that micro-metastasized to lung and liver. Concurrent increase in Hhg marker expression, TICs and acquisition of epithelial mesenchymal transition were observed in the cells derived from these tumors. Depletion of GLI1 in OHTR cells resulted in reduced proliferation, colony formation and mammosphere formation and increased apoptosis in presence of tamoxifen. Treatment of OHTR cells with GDC-0449 and tamoxifen inhibited cell proliferation in vitro and supressed tumor growth and distant metastasis of tamoxifen resistant xenografts in mice. Primary human breast tumors expressing higher level of GLI1 demonstrated a trend towards increased risk of recurrence (p= 0.08) after tamoxifen therapy.

Conclusions: Our work has demonstrated for the first time that activated Hhg signaling is an alternate survival mechanism for tamoxifen resistant breast cancer. Furthermore, targeting these tumors with a combination of tamoxifen and anti-Hhg therapy inhibited tumor growth and development of distant metastases demonstrating efficacy of this approach. Clinical trials using this combination in patients with advanced ER+ breast cancer are warranted and are under development.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-01-07.

Isolation and characterization of nucleotide-binding site and C-terminal leucine-rich repeat-resistance gene candidates in bananas

Commercial banana varieties are highly susceptible to fungal pathogens, as well as bacterial pathogens, nematodes, viruses, and insect pests. The largest known family of plant resistance genes encodes proteins with nucleotide-binding site (NBS) and C-terminal leucine-rich repeat (LRR) domains. Conserved motifs in such genes in diverse plant species offer a means for the isolation of candidate genes in banana that may be involved in plant defense. Six degenerate PCR primers were designed to target NBS and additional domains were tested on commercial banana species Musa acuminata subsp malaccensis and the Musa AAB Group propagated in vitro and plants maintained in a greenhouse. Total DNA was isolated by a modified CTAB extraction technique. Four resistance gene analogs were amplified and deposited in GenBank and assigned numbers HQ199833-HQ199836. The predicted amino acid sequences compared to the amino acid sequences of known resistance genes (MRGL1, MRGL2, MRGL3, and MRGL4) revealed significant sequence similarity. The presence of consensus domains, namely kinase-1a, kinase-2 and hydrophobic domain, provided evidence that the cloned sequences belong to the typical non-Toll/interleukin-1 receptor-like domain NBS-LRR gene family.

S5-3: Basement Membrane Localized Tumor Cells Are Protected from HER2−Targeted Therapy In Vivo

Drug resistance compromises the efficacy of HER2−targeted therapy. Results from our laboratory, and previous reports from others, indicate that tumor cell attachment to basement membrane (BM) and other extracellular matrix (ECM) proteins may confer drug resistance. We have discovered a differential drug response between the outer, matrix-attached cells and inner matrix-deprived cells comprising 3-dimensional (3D) tumor spheroids grown in reconstituted basement membrane (T. Muranen and J. Brugge, unpublished data). The outer matrix-attached cells are resistant to multiple drug therapies. To address whether these observations are relevant in vivo, we utilized a previously described model of human-in-mouse HER2−positive ductal carcinoma in situ (DCIS), which involves the intraductal transplantation of human HER2−positive SUM225 tumor cells directly into the ductal network of the mouse mammary gland. The intraductal tumors generated are histologically indistinguishable from human DCIS lesions and recapitulate the architecture of the 3D tumor spheroids. The tumors are characterized by organized nests of noninvasive cells confined within a BM surrounded by ECM. These features permit a direct assessment of differential drug response within the tumor. We focused on the tumor cell response to short-term lapatinib monotherapy in vivo. A close examination of the tumor architecture revealed that cells closest to the basement membrane, and nearest to the vasculature, display a striking insensitivity to lapatinib whereas the remainder of the tumor undergoes extensive cell death in response to treatment. Further characterization also revealed that cells closest to the basement membrane largely maintain proliferative capacity despite an overall significant reduction in the total Ki67-positive cell population. These results provide in vivo evidence that basement membrane-attached tumor cells are protected from lapatinib. We confirmed that these cells maintain HER2 status and also observed an overall reduction in pHER2, pAKT and pERK throughout the tumor suggestive of adaptive response mechanisms, which support the proliferation and survival of these cell populations despite inhibition of the HER2 pathway. To further explore potential mechanisms of the adaptive response, we performed reverse phase protein array (RPPA) analysis on protein lysates prepared from tumor biopsy fragments following lapatinib monotherapy. RPPA profile analysis revealed an adaptive response composed of upregulation of multiple RTKs (HER2, IGFI-R) and altered apoptotic protein levels (Bcl-2, Bim, Bcl-xL) in addition to activation of AKT/S6K and ERK/p38 pathway components. These observations suggest that basement membrane-attached tumor cells may escape from lapatinib response via compensatory activation of these survival mechanisms. Each of these components will serve as targets for designing combined therapeutic approaches capable of targeting the protected basement membrane-attached tumor cells. Our results suggest that resistant populations may be a source of residual disease post-therapy, therefore identifying and characterizing these cells will be crucial to the prevention of disease recurrence in the clinic.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr S5-3.

Effect of MWCNTs on Gastric Emptying in Mice

After making model of gastric functional disorder (FD), part of model mice were injected intravenously (i.v.) with oxide multi-walled carbon nanotubes (oMWCNTs) to investigate effect of carbon nanotubes on gastric emptying. The results showed that NO content in stomach, compared with model group, was decreased significantly and close to normal level post-injection with oMWCNTs (500 and 800 μg/mouse). In contrast to FD or normal groups, the content of acetylcholine (Ach) in stomach was increased obviously in injection group with 500 or 800 μg/mouse of oMWCNTs. The kinetic curve of emptying was fitted to calculate gastric motility factor k; the results showed that the k of injection group was much higher than FD and normal. In other words, the gastric motility of FD mice was enhanced via injection with oMWCNTs. In certain dosage, oMWCNTs could improve gastric emptying and motility.

Search for supersymmetry at the LHC in events with jets and missing transverse energy

A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at √s=7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14 fb(-1). In this search, a kinematic variable α(T) is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In this model, squark masses below 1.1 TeV are excluded at 95% C.L. Gluino masses below 1.1 TeV are also ruled out at 95% C.L. for values of the universal scalar mass parameter below 500 GeV.

Search for new physics with a monojet and missing transverse energy in pp collisions at √s = 7 TeV

A study of events with missing transverse energy and an energetic jet is performed using pp collision data at a center-of-mass energy of 7 TeV. The data were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 36 pb(-1). An excess of these events over standard model contributions is a signature of new physics such as large extra dimensions and unparticles. The number of observed events is in good agreement with the prediction of the standard model, and significant extension of the current limits on parameters of new physics benchmark models is achieved.

Search for B(s)(0) → μ+ μ- and B(0) → μ+ μ- decays in pp collisions at sqrt[s] = 7 TeV

A search for the rare decays B(s)(0) → μ+ μ- and B(0) → μ+ μ- is performed in pp collisions at sqrt[s] = 7 TeV, with a data sample corresponding to an integrated luminosity of 1.14 fb(-1), collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations from background and standard-model signal predictions. The resulting upper limits on the branching fractions are B(B(s)(0) → μ+ μ-) < 1.9 × 10(-8) and B(B(0) → μ+ μ-)<4.6 × 10(-9), at 95% confidence level.

TWIST1 promotes the odontoblast-like differentiation of dental stem cells

Stem cells derived from the dental pulp of extracted human third molars (DPSCs) have the potential to differentiate into odontoblasts, osteoblasts, adipocytes, and neural cells when provided with the appropriate conditions. To advance the use of DPSCs for dentin regeneration, it is important to replicate the permissive signals that drive terminal events in odontoblast differentiation during tooth development. Such a strategy is likely to restore a dentin matrix that more resembles the tubular nature of primary dentin. Due to the limitations of culture conditions, the use of ex vivo gene therapy to drive the terminal differentiation of mineralizing cells holds considerable promise. In these studies, we asked whether the forced expression of TWIST1 in DPSCs could alter the potential of these cells to differentiate into odontoblast-like cells. Since the partnership between Runx2 and Twist1 proteins is known to control the onset of osteoblast terminal differentiation, we hypothesized that these genes act to control lineage determination of DPSCs. For the first time, our results showed that Twist1 overexpression in DPSCs enhanced the expression of DSPP, a gene that marks odontoblast terminal differentiation. Furthermore, co-transfection assays showed that Twist1 stimulates Dspp promoter activity by antagonizing Runx2 function in 293FT cells. Analysis of our in vitro data, taken together, suggests that lineage specification of DPSCs can be modulated through ex vivo gene modifications.

Biological characteristics of a cell subpopulation in tongue squamous cell carcinoma

OBJECTIVES

To isolate the CD133+CD44+ cells from human tongue squamous cell carcinoma (TSCC) Tca8113 cell line and investigate biological characteristics of them.

MATERIALS AND METHODS

Immunomagnetic microbeads were applied to sort the CD133+CD44+ cells. Flow cytometry was used to detect isolation purity. The proliferation, clone-formation efficiencies, invasion and migration, gene expressions, and tumor-formation abilities were analyzed among CD133+CD44+, CD133-CD44-, and total population of cells.

RESULTS

The average purities of CD133+ and CD44+ cells reached 97.3% and 98.7%, respectively. The proliferation of CD133+CD44+ cells was significantly higher than the other two groups. The clone-forming efficiency of three groups was 70%, 8%, and 14%, respectively. The average invaded and migrated cell numbers of CD133+CD44+ and total population cells were 132 and 36.2, 311.6, and 156.2, respectively. The expressions of Bcl-2 and Sox2 in CD133+CD44+ cells were significantly higher than those in total population cells. A total of 10(4) CD133+CD44+ cells could form secondary tumors in nude mice, while the total population group needed 10(6) cells.

CONCLUSIONS

The CD133+CD44+ subpopulation cells possess stem-like characteristics. They appear to be the potential targets for future biology therapy of human TSCC.

Frontotemporal dementia caregivers and researchers: partnering for brain donation

This study utilized a community-based, participatory research model between the Association for Frontotemporal Degeneration (AFTD) and the Education Core of the Indiana Alzheimer Disease Center. A total of 30 caregivers of persons with frontotemporal dementia (FTD) participated in 6 focus groups in 3 cities. The majority of participants were spouses of the person with FTD and had been providing care for an average of 6 years. Transcript analysis revealed 7 prominent themes: willingness to participate, when/how the issue of brain donation is raised, who initiates discussion about brain donation, who is involved in decisions about brain donation, motivation for participating in brain donation, lack of effective communication, and barriers to research participation. Caregivers demonstrated a strong desire to participate in research and contribute to advancing knowledge. The lack of effective communication between the clinicians and caregivers was a barrier to developing positive rapport, detrimentally impacting research participation.

βA3/A1-Crystallin controls anoikis-mediated cell death in astrocytes by modulating PI3K/AKT/mTOR and ERK survival pathways through the PKD/Bit1-signaling axis

During eye development, apoptosis is vital to the maturation of highly specialized structures such as the lens and retina. Several forms of apoptosis have been described, including anoikis, a form of apoptosis triggered by inadequate or inappropriate cell–matrix contacts. The anoikis regulators, Bit1 (Bcl-2 inhibitor of transcription-1) and protein kinase-D (PKD), are expressed in developing lens when the organelles are present in lens fibers, but are downregulated as active denucleation is initiated. We have previously shown that in rats with a spontaneous mutation in the Cryba1 gene, coding for βA3/A1-crystallin, normal denucleation of lens fibers is inhibited. In rats with this mutation (Nuc1), both Bit1 and PKD remain abnormally high in lens fiber cells. To determine whether βA3/A1-crystallin has a role in anoikis, we induced anoikis in vitro and conducted mechanistic studies on astrocytes, cells known to express βA3/A1-crystallin. The expression pattern of Bit1 in retina correlates temporally with the development of astrocytes. Our data also indicate that loss of βA3/A1-crystallin in astrocytes results in a failure of Bit1 to be trafficked to the Golgi, thereby suppressing anoikis. This loss of βA3/A1-crystallin also induces insulin-like growth factor-II, which increases cell survival and growth by modulating the phosphatidylinositol-3-kinase (PI3K)/AKT/mTOR and extracellular signal-regulated kinase pathways. We propose that βA3/A1-crystallin is a novel regulator of both life and death decisions in ocular astrocytes.

In vitro rumen fermentation and methane production are influenced by active components of essential oils combined with fumarate

Two trials were conducted to identify the optimal levels of essential oil active components (EOAC) and their combination with fumarate on in vitro rumen fermentation. In trial 1, eugenol, carvacrol, citral and cinnamaldehyde were mixed at ratios of 1:2:3:4, 2:1:4:3, 3:4:1:2, 4:3:2:1 and 1:1:1:1 to make up five combinations (EOAC1, EOAC2, EOAC3, EOAC4 and EOAC5 respectively). The mixtures were supplied at levels of 0, 50, 200 or 500 mg/l to identify the optimal combination for methane reduction. Methane production and ammonia nitrogen were decreased by adding EOAC, irrespective of component compounds, but the production of gas and total volatile fatty acids (VFA) were also decreased. Hydrogen balance analysis indicated that the ratio of hydrogen consumed via methane to hydrogen consumed via VFA was lowest at 200 mg/l of EOAC5 treatment, from which the proportional change in methane was more than the change in VFA, with 31.5% of methane reduction and 12.9% of VFA reduction. In trial 2, 200 mg/l of EOAC5 was added with 0, 5, 10 and 15 mm monosodium fumarate to see whether fumarate had a further effect on rumen fermentation. The addition of fumarate had no influence on gas production, but it further decreased methane and increased the total VFA in comparison with EOAC added solely, with the greatest decrease occurring in methane (78.1%) from 10 mm of fumarate. Quantification of the microbial populations in rumen fluids by RT-PCR showed that methanogen, protozoa, fungi, Fibrobacter succinogenes and Ruminococcus flavefaciens populations were significantly decreased by EOAC5, but were not influenced by fumarate. In summary, the addition of EOAC had consistent effects on rumen fermentation parameters, but high levels of EOAC would induce the inhibition of rumen fermentation. Adding fumarate can enhance the methane-inhibiting effect of EOAC, and the decrease was higher than that calculated stoichiometrically.

Establishment, characterization and viral susceptibility of a new cell line derived from goldfish, Carassius auratus (L.), tail fin

A continuous cell line [goldfish tail fin (GFTF)] derived from a goldfish tail fin, Carassius auratus, was established and characterized. GFTF cells predominantly consist of fibroblast-like cells that were maintained and subcultured more than 50 times over a period of 15 months. Cells grew at temperatures between 15 and 37°C, with an optimum temperature of 25°C. The growth rate of GFTF cells increased proportionally with the foetal bovine serum (FBS) concentration (5-20%), with optimum growth at 20% FBS. The chromosome numbers were 88-112, with a modal peak of 104 chromosomes. Five known fish viruses were tested to determine susceptibility. Results demonstrated that GFTF is susceptible to snakehead rhabdovirus, spring viraemia of carp virus and channel catfish virus (CCV). In addition, GFTF demonstrated a higher sensitivity to, and increased viral production of, CCV than that observed in the control cell line, channel catfish ovary cells. This suggests that GFTF cells would be useful as a diagnostic tool for viral diseases in this fish species, as well as for the isolation and study of goldfish viruses in the future. Furthermore, these cells were transfected with pEGFP-N1 vector DNA and some fluorescent signals were observed, suggesting that GFTF cells could be a useful tool for transgenic and genetic manipulation studies.

High sensitivity of taper-based Mach-Zehnder interferometer embedded in a thinned optical fiber for refractive index sensing

A taper-based Mach-Zehnder interferometer (MZI) embedded in a thinned optical fiber is demonstrated as a highly sensitive refractive index (RI) sensor. A RI sensitivity of 2210.84 nm/RIU (refractive index unit) is obtained at the external RI of 1.40, which is ten times higher than that of normal taper- and long-period fiber grating (LPFG)-based sensors. The sensitivity can be further improved by decreasing the diameter of the thinned fiber and increasing the interferometer length of the MZI. The proposed MZIs have lower temperature sensitivities compared with normal fiber sensors, which is a desirable merit for RI sensors to reduce the cross sensitivity caused by thermal drift.