The Complex, Unique, and Powerful Imaging Instrument for Dynamics (CUPI2D) at the Spallation Neutron Source (invited)

The Oak Ridge National Laboratory is planning to build the Second Target Station (STS) at the Spallation Neutron Source (SNS). STS will host a suite of novel instruments that complement the First Target Station's beamline capabilities by offering an increased flux for cold neutrons and a broader wavelength bandwidth. A novel neutron imaging beamline, named the Complex, Unique, and Powerful Imaging Instrument for Dynamics (CUPI2D), is among the first eight instruments that will be commissioned at STS as part of the construction project. CUPI2D is designed for a broad range of neutron imaging scientific applications, such as energy storage and conversion (batteries and fuel cells), materials science and engineering (additive manufacturing, superalloys, and archaeometry), nuclear materials (novel cladding materials, nuclear fuel, and moderators), cementitious materials, biology/medical/dental applications (regenerative medicine and cancer), and life sciences (plant-soil interactions and nutrient dynamics). The innovation of this instrument lies in the utilization of a high flux of wavelength-separated cold neutrons to perform real time in situ neutron grating interferometry and Bragg edge imaging-with a wavelength resolution of δλ/λ ≈ 0.3%-simultaneously when required, across a broad range of length and time scales. This manuscript briefly describes the science enabled at CUPI2D based on its unique capabilities. The preliminary beamline performance, a design concept, and future development requirements are also presented.

Neutron Radiography and Computed Tomography of Biological Systems at the Oak Ridge National Laboratory's High Flux Isotope Reactor

Neutrons have historically been used for a broad range of biological applications employing techniques such as small-angle neutron scattering, neutron spin echo, diffraction, and inelastic scattering. Unlike neutron scattering techniques that obtain information in reciprocal space, attenuation-based neutron imaging measures a signal in real space that is resolved on the order of tens of micrometers. The principle of neutron imaging follows the Beer-Lambert law and is based on the measurement of the bulk neutron attenuation through a sample. Greater attenuation is exhibited by some light elements (most notably, hydrogen), which are major components of biological samples. Contrast agents such as deuterium, gadolinium, or lithium compounds can be used to enhance contrast in a similar fashion as it is done in medical imaging, including techniques such as optical imaging, magnetic resonance imaging, X-ray, and positron emission tomography. For biological systems, neutron radiography and computed tomography have increasingly been used to investigate the complexity of the underground plant root network, its interaction with soils, and the dynamics of water flux in situ. Moreover, efforts to understand contrast details in animal samples, such as soft tissues and bones, have been explored. This manuscript focuses on the advances in neutron bioimaging such as sample preparation, instrumentation, data acquisition strategy, and data analysis using the High Flux Isotope Reactor CG-1D neutron imaging beamline. The aforementioned capabilities will be illustrated using a selection of examples in plant physiology (herbaceous plant/root/soil system) and biomedical applications (rat femur and mouse lung).

Pharmacokinetic characterization of fluorocoxib D, a cyclooxygenase-2-targeted optical imaging agent for detection of cancer

SIGNIFICANCE

Fluorocoxib D, N-[(rhodamin-X-yl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide, is a water-soluble optical imaging agent to detect cyclooxygenase-2 (COX-2)-expressing cancer cells.

AIM

We evaluated the pharmacokinetic and safety properties of fluorocoxib D and its ability to detect cancer cells in vitro and in vivo.

APPROACH

Pharmacokinetic parameters of fluorocoxib D were assessed from plasma collected at designated time points after intravenous administration of 1  mg  /  kg fluorocoxib D in six research dogs using a high-performance liquid chromatography analysis. Safety of fluorocoxib D was assessed for 3 days after its administration using physical assessment, complete blood count, serum chemistry profile, and complete urinalysis in six research dogs. The ability of fluorocoxib D to detect COX-2-expressing cancer cells was performed using human 5637 cells in vitro and during rhinoscopy evaluation of specific fluorocoxib D uptake by canine cancer cells in vivo.

RESULTS

No evidence of toxicity and no clinically relevant adverse events were noted in dogs. Peak concentration of fluorocoxib D (114.8  ±  50.5  ng  /  ml) was detected in plasma collected at 0.5 h after its administration. Pretreatment of celecoxib blocked specific uptake of fluorocoxib D in COX-2-expressing human 5637 cancer cells. Fluorocoxib D uptake was detected in histology-confirmed COX-2-expressing head and neck cancer during rhinoscopy in a client-owned dog in vivo. Specific tumor-to-normal tissue ratio of detected fluorocoxib D signal was in an average of 3.7  ±  0.9 using Image J analysis.

CONCLUSIONS

Our results suggest that fluorocoxib D is a safe optical imaging agent used for detection of COX-2-expressing cancers and their margins during image-guided minimally invasive biopsy and surgical procedures.

Detection of carcinogen-induced bladder cancer by fluorocoxib A

BACKGROUND

Conventional cystoscopy can detect advanced stages of bladder cancer; however, it has limitations to detect bladder cancer at the early stages. Fluorocoxib A, a rhodamine-conjugated analog of indomethacin, is a novel fluorescent imaging agent that selectively targets cyclooxygenase-2 (COX-2)-expressing cancers.

METHODS

In this study, we have used a carcinogen N-butyl-N-4-hydroxybutyl nitrosamine (BBN)-induced bladder cancer immunocompetent mouse B6D2F1 model that resembles human high-grade invasive urothelial carcinoma. We evaluated the ability of fluorocoxib A to detect the progression of carcinogen-induced bladder cancer in mice. Fluorocoxib A uptake by bladder tumors was detected ex vivo using IVIS optical imaging system and Cox-2 expression was confirmed by immunohistochemistry and western blotting analysis. After ex vivo imaging, the progression of bladder carcinogenesis from normal urothelium to hyperplasia, carcinoma-in-situ and carcinoma with increased Ki67 and decreased uroplakin-1A expression was confirmed by histology and immunohistochemistry analysis.

RESULTS

The specific uptake of fluorocoxib A correlated with increased Cox-2 expression in progressing bladder cancer. In conclusion, fluorocoxib A detected the progression of bladder carcinogenesis in a mouse model with selective uptake in Cox-2-expressing bladder hyperplasia, CIS and carcinoma by 4- and 8-fold, respectively, as compared to normal bladder urothelium, where no fluorocoxib A was detected.

CONCLUSIONS

Fluorocoxib A is a targeted optical imaging agent that could be applied for the detection of Cox-2 expressing human bladder cancer.

Detection of tyrosine kinase inhibitors-induced COX-2 expression in bladder cancer by fluorocoxib A

Among challenges of targeted therapies is the activation of alternative pro-survival signaling pathways in cancer cells, resulting in an acquired drug resistance. Cyclooxygenase-2 (COX-2) is overexpressed in bladder cancer cells, making it an attractive molecular target for the detection and treatment of cancer. Fluorocoxib A is an optical imaging agent that selectively targets COX-2. In this study, we evaluated the ability of fluorocoxib A to monitor the responses of bladder cancer to targeted therapies in vivo. The effects of several tyrosine kinase inhibitors (TKIs: axitinib, AB1010, toceranib, imatinib, erlotinib, gefitinib, imatinib, sorafenib, vandetanib, SP600125, UO126, and AZD 5438) on COX-2 expression were validated in ten human and canine bladder cancer cell lines (J82, RT4, T24, UM-UC-3, 5637, SW780, TCCSUP, K9TCC#1Lillie, K9TCC#2Dakota, K9TCC#5Lilly) in vitro. The effects of TKIs on bladder cancer in vivo were evaluated using the COX-2-expressing K9TCC#5Lilly xenograft mouse model and detected by fluorocoxib A. The increased COX-2 expression was detected by all tested TKIs in at least one of the tested COX-2-expressing bladder cancer cell lines (5637, SW780, TCCSUP, K9TCC#1Lillie, K9TCC#2Dakota, and K9TCC#5Lilly) in vitro. In addition, fluorocoxib A uptake correlated with the AB1010- and imatinib-induced COX-2 expression in the K9TCC#5Lilly xenografts in vivo. In conclusion, these results indicate that fluorocoxib A could be used for the monitoring the early responses to targeted therapies in COX-2-expressing bladder cancer.

Platelet-rich plasma affects the proliferation of canine bone marrow-derived mesenchymal stromal cells in vitro

BACKGROUND

Reported efficacy of platelet-rich plasma (PRP) in regenerative medicine is contradictory. We validated the effects of PRP on proliferation of canine bone marrow-derived multipotent mesenchymal stromal cells (K9BMMSCs) in vitro. PRP was extracted from blood of six dogs with osteoarthritis. K9BMMSCs were established from bone marrow and characterized for CD90 and CD19 expression by immunocytochemistry. Effects of PRP concentrations on viability of matching autologous K9BMMSCs were validated using MTS assay.

RESULTS

Positive CD90 and negative CD19 expression confirmed MSC origin. PRP at 40% volume/volume concentration increased, while PRP at 80 and 100% v/v concentrations suppressed viability of tested K9BMMSCs.

CONCLUSION

PRP concentration plays an important role in K9BMMSCs viability, which could affect tissue repairs in vivo.

Abstract 885: Anthracycline-induced apoptosis through caspase3/7 activity is p53-dependent in bladder cancer cells

Doxorubicin (Dox) is a chemotherapy drug widely used for treatment of several cancers including bladder cancer. However, cardiovascular side effects caused by doxorubicin-induced cardiotoxicity has necessitated the synthesis and validation of next generation chemotherapy drugs that are as effective but not cardiotoxic. AD 312 (N-Nitrosureidodaunorubicin; Daunomustine®, Paradox Pharmaceuticals, Inc.) and AD 198 (N- benzyladriamycin-14-valerate; Benzarubicin®, Paradox Pharmaceuticals, Inc.) are novel anthracyclines with confirmed non-cardiotoxicity in mice. Compared to Dox, AD 312 and AD 198 induce apoptosis in cells through distinct mechanisms. The tumor suppressor gene p53 is a key regulator of cell-cycle arrest and apoptosis. Dysregulation of p53 expression and function was identified in over 70% of the bladder cancers and reported as a potential target for therapy. As a result, small molecule compounds that can restore mutated p53 function to wild-type, including PRIMA-1, are under intensive investigation. In this study, we have compared the efficacy of AD 312 and AD 198 to Dox to induce apoptosis in human bladder transitional cell carcinoma (TCC) cells by MTT assay and assessed the possible mechanisms of anthracyclines-induced apoptosis in TCC cells expressing wild-type (wt) p53 (RT4, SW780) and mutated (mt) p53 (UM-UC-3, 5637, J82, and TCCSUP) protein. We have also investigated the effects of co-treatment of anthracyclines with PRIMA-1 in J82 cells, as a representative mt-p53 TCC cell line, and compared the co-treatment effects in RT4, as a representative wt-p53 cell line. Our results demonstrated that anthracyclines inhibited cell viability of all tested TCC cells in vitro, with AD 198 demonstrating highest efficacy. Furthermore, anthracyclines upregulated p53 protein expression in wt-p53 RT4 and SW780 cells, but not in tested mt-p53 UM-UC-3, 5637, J82, and TCCSUP cells. A strong correlation was observed between p53 mutation status and activation of caspase 3/7 and cleavage of PARP. The upregulated caspase 3/7 activity and PARP cleavage was observed in wt-p53, but not in mt-p53 TCC cells. AD198 blocked c-myc expression in mt-p53 TCC cells and no expression of c-myc was detected in wt-p53 TCC cells. Furthermore, sensitivity to AD 198 treatment in mt-p53 J82 cells was significantly improved by a co-treatment with PRIMA-1. However, PRIMA-1 had no effect on cell viability in RT4, the wt-p53 TCC cells. Overall, our results demonstrated that AD 312 and AD 198 are potent inhibitors of bladder cancer cells in vitro and are promising candidates for new therapeutic strategies to replace Dox for bladder cancer treatment. PRIMA-1 even further sensitized mt-p53 cells to AD 198 treatment and thereby this co-treatment improved the inhibition of bladder cancer in vitro.

Citation Format: Sony Pandey, Leonard Lothstein, Maria Cekanova. Anthracycline-induced apoptosis through caspase3/7 activity is p53-dependent in bladder cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 885.

Mutations of p53 decrease sensitivity to the anthracycline treatments in bladder cancer cells

Due to doxorubicin (Dox) cardiotoxicity, the next generation of novel non-cardiotoxic anthracyclines, including AD 312 and AD 198, were synthesized and validated. In this study, we assessed the efficacy and mechanisms of anthracyclines-induced apoptosis and inhibition of cell viability in human bladder cancer cells expressing wild-type (wt) p53 (RT4 and SW780) and mutated (mt) p53 (UM-UC-3, 5637, T-24, J82, and TCCSUP) protein. Anthracyclines inhibited cell viability in tested TCC cells, but were less effective in mt-p53 TCC cells, especially in the drug-resistant J82 and TCCSUP cells. Anthracyclines upregulated the expression of wt p53 protein in RT4 and SW780 cells, but had no effect on expression of mt p53 protein in UM-UC-3, 5637, T-24, J82, and TCCSUP cells. The anthracyclines activated caspase 3/7 and cleavage of PARP in wt-p53 RT4 and SW780 cells, and mt-p53 5637, UM-UC-3, and T-24, but not in mt-p53 J82 and TCCSUP cells. The anthracyclines-induced cleavage of PARP was blocked by p53 siRNA in wt-p53 RT4 cells. Co-treatment of AD 198 with PRIMA-1 significantly inhibited cell viability of mt-p53 J82 cells, but had no effect in wt-p53 RT4 cells. AD 198 blocked c-myc expression in mt-p53 UM-UC-3, 5637, T-24, and J82 cells, however no expression of c-myc was detected in wt-p53 RT4 and SW780 cells. In conclusion, our results demonstrated that the anthracycline-induced resistance in bladder cancer cells positively correlated with TP53 mutations in the tetramerization domain in J82 and TCCSUP cells. Further, AD 312 and AD 198 are promising chemotherapeutic drugs for bladder cancer, especially in combination with PRIMA-1.

Cyclooxygenase inhibitors potentiate receptor tyrosine kinase therapies in bladder cancer cells in vitro

Purpose

Receptor tyrosine kinase inhibitors (RTKIs) are used as targeted therapies for patients diagnosed with cancer with highly expressed receptor tyrosine kinases (RTKs), including the platelet-derived growth factor receptor (PDGFR) and c-Kit receptor. Resistance to targeted therapies is partially due to the activation of alternative pro-survival signaling pathways, including cyclooxygenase (COX)-2. In this study, we validated the effects of two RTKIs, axitinib and AB1010, in combination with COX inhibitors on the V-akt murine thymoma oncogene homolog 1 (Akt) and COX-2 signaling pathways in bladder cancer cells.

Methods

The expression of several RTKs and their downstream signaling targets was analyzed by Western blot (WB) analysis in human and canine bladder transitional cell carcinoma (TCC) cell lines. The effects of RTKIs and COX inhibitors in bladder TCC cells were assessed by MTS for cell viability, by Caspase-3/7 and Annexin V assay for apoptosis, by WB analysis for detection of COX-2 and Akt signaling pathways, and by enzyme-linked immunosorbent assay for detection of prostaglandin E2 (PGE₂) levels.

Results

All tested TCC cells expressed the c-Kit and PDGFRα receptors, except human 5637 cells that had low RTKs expression. In addition, all tested cells expressed COX-1, COX-2, Akt, extracellular signal regulated kinases 1/2, and nuclear factor kappa-light-chain-enhance of activated B cells proteins, except human UM-UC-3 cells, where no COX-2 expression was detected by WB analysis. Both RTKIs inhibited cell viability and increased apoptosis in a dose-dependent manner in tested bladder TCC cells, which positively correlated with their expression levels of the PDGFRα and c-Kit receptors. RTKIs increased the expression of COX-2 in h-5637 and K9TCC#1Lillie cells. Co-treatment of indomethacin inhibited AB1010-induced COX-2 expression leading to an additive effect in inhibition of cell viability and PGE₂ production in tested TCC cells.

Conclusion

Co-treatment of RTKIs with indomethacin inhibited cell viability and AB1010-induced COX-2 expression resulting in decreased PGE₂ production in tested TCC cells. Thus, COX inhibition may further potentiate RTKIs therapies in bladder cancer.

Aligned nanofiber material supports cell growth and increases osteogenesis in canine adipose-derived mesenchymal stem cells in vitro

Tissue engineering shows great promise for the treatment of degenerative diseases, including bone repair. Polymer nanofibers provide a three-dimensional (3-D) scaffold for attachment and growth of mesenchymal stem cells. Increasing evidence supports that fiber alignment on scaffolds plays a major role in the viability and differentiation of stem cells. We compared the cell viability of canine adipose tissue-derived mesenchymal stem cells (cADMSCs) cultured in the aligned- (NanoAligned™) and random- (NanoECM™) oriented polycaprolactone (PCL) nanofiber-coated plates to control polystyrene tissue culture plates using a proliferation assay. Ability of the plates to induce differentiation of cADMSCs into osteocytes, adipocytes, and neurons was evaluated based on expression of the osteocyte markers, COL1A1 and osterix; adipocyte markers PPARγ2 and LPL; and neuronal marker nestin using RT-PCR. Proliferation results demonstrated that aligned-oriented PCL nanofiber-coated plates were more suitable substrate for cADMSCs after 7 days in culture compared to random-oriented PCL nanofiber-coated or control plates. Additionally, we demonstrated that both 3-D PCL nanofiber-coated plates were a better scaffold for cADMSCs differentiation into osteocytes compared to control plates. In conclusion, our results confirm that PCL nanofiber is a suitable tissue engineering material for use in regenerative medicine for canine patients in vivo. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1780-1788, 2018.

Inhibition of the PI3K/AKT Pathway Sensitizes Oral Squamous Cell Carcinoma Cells to Anthracycline-Based Chemotherapy In Vitro

Anthracycline-based chemotherapy, such as doxorubicin (Dox), while effective against many solid tumors, is not widely used for head and neck cancers. In this study, we evaluated the efficacy of Dox, and its derivative AD198 in human, canine, and feline oral squamous cell carcinomas cells (OSCC) in vitro. Dox and AD198 had significant an anti-proliferative effect on human, canine, and feline OSCC cells in dose-dependent manner. AD198 inhibited cell proliferation more effectively than Dox in tested OSCC cells. In the human oral squamous cell carcinoma SCC25 cells, Dox and AD198 increased the production of reactive oxygen species and subsequently increased apoptosis through activation of caspase signaling pathway. Dox and AD198 increased activation of AKT, ERK1/2, and p38 MAPK signaling pathways in tested OSCC cells by dose-dependent manner. The efficacy of Dox and AD198 treatments in inhibition of cell proliferation was increased in tested OSCC when combined with PI3K/AKT inhibitor, LY294002 treatment. Inhibition of PI3K/AKT reduced Dox- and AD198-induced activation of ERK1/2 and further increased Dox- and AD198-induced phosphorylation of p38 MAPK in OSCC. Our results suggest that the anthracycline therapies, such as Dox or AD198, can be more effective for treatment of OSCC when combined with inhibitors of the PI3K/AKT pathway. J. Cell. Biochem. 118: 2615-2624, 2017. © 2016 Wiley Periodicals, Inc.

Molecular targets in urothelial cancer: detection, treatment, and animal models of bladder cancer

Bladder cancer remains one of the most expensive cancers to treat in the United States due to the length of required treatment and degree of recurrence. In order to treat bladder cancer more effectively, targeted therapies are being investigated. In order to use targeted therapy in a patient, it is important to provide a genetic background of the patient. Recent advances in genome sequencing, as well as transcriptome analysis, have identified major pathway components altered in bladder cancer. The purpose of this review is to provide a broad background on bladder cancer, including its causes, diagnosis, stages, treatments, animal models, as well as signaling pathways in bladder cancer. The major focus is given to the PI3K/AKT pathway, p53/pRb signaling pathways, and the histone modification machinery. Because several promising immunological therapies are also emerging in the treatment of bladder cancer, focus is also given on general activation of the immune system for the treatment of bladder cancer.

Abstract 4739: The upregulation of cyclooxygenase-2 protein expression by receptor tyrosine kinase inhibitors in bladder cancer in vitro

Several types of cancer, including transitional cell carcinoma (TCC) overexpress several receptor tyrosine kinases (RTKs), including the platelet-derived growth factor receptor (PDGFR), c-kit receptor, epidermal growth factor receptor (EGFR), as well as the vascular endothelial growth factor receptor (VEGFR). Receptor tyrosine kinase inhibitors (RTKIs) are used as targeted therapies for patients diagnosed with cancer with high expression of RTKs. Cyclooxygenase-2 (COX-2) is highly expressed in bladder cancer as well other types of cancers and is one of the key proteins during tumorigenesis. In this study, we validated the effects of RTKIs, Masitinib® (AB1010) and Axitinib on cell proliferation of human (UMUC-3 and T24) and canine (K9TCC#1Lillie, K9TCC#2Dakota, and K9TCC#5Lilly) bladder TCC cells. Using WB analysis, tested human and canine TCC cells, except T24 cells, expressed PDGFR and c-kit receptors. There was no detectable EGFR and VEGFR expressions in any of tested cells by WB analysis. The K9TCC#1Lillie and K9TCC#5Lilly cells had a high expression of COX-2, however K9TCC#2Dakota and human T24 had moderate expression of COX-2, and no COX-2 expression was detected in UMUC3 cells by WB analysis. Both RTKIs, Masitinib® and Axitinib inhibited cell proliferation of the tested human and canine bladder TCC cells in a dose-dependent manner by MTS and apoptosis assays. Interestingly, both tested RTKIs, Masitinib® and Axitinib increased COX-2 protein expressions in tested canine TCC cells. Combined treatment of RTKIs with COX-2 inhibitors decreased cell proliferation of tested TCC cells more effectively as either treatments alone. Our results indicate a possible role of COX-2 signaling pathway in developed RTKIs-resistance in bladder cancer cells in vitro. Co-treatment of RTKIs with COX-2 inhibitors might indicate better clinical outcomes in treatments of patients diagnosed with bladder cancer.

Citation Format: Jennifer Bourn, Maria Cekanova. The upregulation of cyclooxygenase-2 protein expression by receptor tyrosine kinase inhibitors in bladder cancer in vitro. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4739.

Abstract C182: Novel derivative of doxorubicin, AD198, for treatment of bladder transitional cell carcinomas in vitro

Human bladder cancer is one of the most expensive cancers to treat due to its high rate of reoccurrence. Development and characterization of animal models for human cancers is important for the improvement of diagnosis and therapy. The bladder transitional cell carcinoma (TCC) of domestic animals resembles human bladder TCC in many aspects, therefore cell lines derived from bladder TCC of dogs are valuable model for studying human bladder TCC. A chemotherapeutic agent, Doxorubicin (Dox), is often used to treat advanced bladder cancer. Despite the success of Dox based therapies, drug resistance and cardio-toxicity are limiting factors in treating any cancer with Dox. N-benzyladriamycin-14-valerate (AD198), a novel derivative of Dox has no measurable cardio-toxic effects in the rodent model of lymphoma. In this study, we focused in comparing the efficacy and mechanisms of Dox and AD198 in human and primary canine bladder transitional cell carcinoma (TCC) cells in vitro. Using human T24 and UMUC-3 TCC and three canine primary bladder K9TCC-Dakota, K9TCC-Lillie, and K9TCC-Molly cell lines, we evaluated the Dox and AD198 efficacy on cell proliferation by MTS assay. Caspase 3/7 assay, reactive oxygen species (ROS) production, and western blot analysis were used to study the mechanisms of Dox- and AD198-induced apoptosis. AD198 was more effective than Dox in inhibition of cell proliferation in tested TCC cells in dose-dependent manner. ROS production was increased when compared to control by both Dox and AD198 leading to apoptosis, which was confirmed by caspase 3/7 activity and cleavage of poly ADP ribose polymerase (PARP) in tested TCC cells. AD198 increased ROS production significantly more than Dox in all tested TCC cells. Both Dox and AD198 increased phosphorylation of pro-apoptotic p38 MAPK, while at the same time increased the activity of anti-apoptotic phosphatidylinositol 3-kinase (PI3K/AKT/mTOR) signal transduction pathway in tested TCC cells. When a PI3K inhibitor, LY294002, was used in combination with either Dox or AD198, cell proliferation was inhibited more effectively than when drugs used alone. In addition, cleaved PAPR was increased when TCC cells were co-treated with LY294002 and in combination with Dox or AD198 as compared to either drug alone. Our data suggest that AD198 as novel derivative of Dox may be a valuable treatment option for bladder TCC cancers. Dox- and AD198-induced AKT phosphorylation that is an indicator of pro-survival and drug-resistance mechanisms of chemotherapies in tested bladder TCC cancer. Combined therapy of Dox or AD198 with inhibitors of PI3K/AKT1 pathway might lead to more effective treatment outcome for human and veterinary patients diagnosed with bladder TCC cancer. Evaluation of new therapeutic and imaging drugs that have shown promise in vitro and in vivo in the rodent model are important; however, pet animals like, dogs and cats with naturally-occurring tumors provide an important step for successful translation from rodents to human clinical application.

Citation Format: Dmitriy Smolensky, Kusum Rathore, Maria Cekanova, Maria Cekanova. Novel derivative of doxorubicin, AD198, for treatment of bladder transitional cell carcinomas in vitro. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C182.

Effects of environmental carcinogen benzo(a)pyrene on canine adipose-derived mesenchymal stem cells

Dogs and their owners share the same environment and are subjected to similar environmental risk factors for developing breast cancer. Adipose tissue-derived mesenchymal stem cells (ADMSCs) may affect development and progression of breast cancer. In this study, we evaluated the effects of environmental carcinogen benzo(a)pyrene (BaP) on proliferation and differentiation of ADMSCs isolated from dogs. We characterized eight canine ADMSC lines and studied the effects of BaP on cell proliferation and differentiation. BaP did not inhibit cell proliferation of ADMSCs; however, BaP significantly inhibited differentiation potential of ADMSCs into adipocytes. BaP down-regulated AhR protein levels; however, increased its translocation from the cytoplasm to nucleus and suppressed PPARγ expression during adipogenesis. BaP increased the expression of AhR signaling pathway protein, cytochrome P450 (CYP1A1) in ADMSCs. Our data suggest that canine ADMSCs are susceptible to the environmental carcinogen BaP through AhR and PPARγ signaling pathways and may contribute to canine mammary carcinogenesis.

Phosphatidylinositol- 3-kinase inhibitor induces chemosensitivity to a novel derivative of doxorubicin, AD198 chemotherapy in human bladder cancer cells in vitro

BACKGROUND

Doxorubicin (Dox) is widely used to treat progressed bladder cancer after transurethral resection. The use of Dox-chemotherapy has been limited due to induced drug resistance and cumulative cardiotoxic effects. N-benzyladriamycin-14-valerate (AD198), a novel derivative of Dox, has a potential to become a more effective treatment than Dox by overcoming drug resistance and cardio-toxicity as shown in the rodent model of lymphoma in vivo. The purpose of this study was to compare the efficacy of Dox and AD198 and explore their mechanisms in inhibition on human bladder cancer cells in vitro.

METHODS

We evaluated the effects of Dox and AD198 on cell viability of human transitional cell carcinoma (TCC) cell lines T24 and UMUC3 by MTS assay in vitro. The effects of Dox and AD198 on cell apoptosis were determined by caspase 3/7 assay, generation of reactive oxygen species (ROS), and Western Blotting (WB) analysis.

RESULTS

AD198 was more effective than Dox in inhibition of cell viability of T24 and UMUC3 cells in vitro. Both Dox and AD198 significantly increased the generation of ROS and induced apoptosis in caspase-dependent and -independent manner in T24 and UMUC3 cells. AD 198 induced significantly higher production of ROS as compared to Dox in human TCC cells. Dox and AD198 activated the pro-apoptotic p38 MAPK pathway; however, on the other hand also increased phosphorylation of AKT, an anti-apoptotic signaling pathway, in T24 and UMUC3 cells. Combined treatment of PI3K inhibitor (LY294002) with Dox or AD198 inhibited cell viability of T24 and UMUC3 cells more effectively than any of drug treatments alone.

CONCLUSIONS

These data suggest that AD198 as novel derivative of Dox, could be a used as effective treatment for bladder cancer. Dox and AD198 induced PI3K/AKT signaling pathway that is a one of the indicators of pro-survival and possible drug-resistance mechanisms of chemotherapies in bladder cancer. Combined therapies of Dox or AD198 with inhibitors of PI3K/AKT signaling pathway might lead to more effective treatment outcome for patients diagnosed with bladder cancer based on our in vitro experiments.

A novel derivative of doxorubicin, AD198, inhibits canine transitional cell carcinoma and osteosarcoma cells in vitro

Doxorubicin (DOX) is one of the most commonly used chemotherapeutic treatments for a wide range of cancers. N-benzyladriamycin-14-valerate (AD198) is a lipophilic anthracycline that has been shown to target conventional and novel isoforms of protein kinase C (PKC) in cytoplasm of cells. Because of the adverse effects of DOX, including hair loss, nausea, vomiting, liver dysfunction, and cardiotoxicity, novel derivatives of DOX have been synthesized and validated. In this study, we evaluated the effects of DOX and its derivative, AD198, on cell viability of three canine transitional cell carcinoma (K9TCC) (K9TCC#1-Lillie, K9TCC#2-Dakota, K9TCC#4-Molly) and three canine osteosarcoma (K9OSA) (K9OSA#1-Zoe, K9OSA#2-Nashville, K9OSA#3-JJ) primary cancer cell lines. DOX and AD198 significantly inhibited cell proliferation in all tested K9TCC and K9OSA cell lines in a dose-dependent manner. AD198 inhibited cell viability of tested K9TCC and K9OSA cell lines more efficiently as compared to DOX at the same concentration using MTS (3-(4,5-dimethyl-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2h-tetrazolium) assay. AD198 had lower IC₅₀ values as compared to DOX for all tested K9TCC and K9OSA cell lines. In addition, AD198 increased apoptosis in all tested K9TCC and K9OSA cell lines. AD198 increased the caspase activity in tested K9TCC and K9OSA cell lines, which was confirmed by caspase-3/7 assay, and cleavage of poly (ADP-ribose) polymerase (PARP) was confirmed by Western blotting analysis. In addition, AD198 cleaved PKC-δ, which subsequently activated the p38 signaling pathway, resulting in the apoptosis of tested K9TCC and K9OSA cell lines. Inhibition of the p38 signaling pathway by SB203580 rescued DOX- and AD198-induced apoptosis in tested K9TCC and K9OSA cell lines. Our in vitro results suggest that AD198 might be considered as a new treatment option for K9TCC and K9OSA cell lines cancers in vivo.

A novel approach to determine post mortem interval using neutron radiography

One of the most difficult challenges in forensic research is to objectively determine the post-mortem interval (PMI). The accuracy of PMI is critical for determining the timeline of events surrounding a death. Most PMI techniques rely on gross morphological changes of cadavers that are highly sensitive to taphonomic factors. Recent studies have demonstrated that even exhumed individuals exposed to the same environmental conditions with similar PMIs can present different stages of decomposition. After death, tissue undergoes sequential changes consisting of organic and inorganic phase variations, as well as a gradual reduction of tissue water content. Hydrogen (H) is the primary contributor to neutron radiography (NR) contrast in biological specimens because (1) it is the most abundant element in biological tissues and (2) its nucleus scatters thermal and cold neutrons more strongly than any other atomic nucleus. These contrast differences can be advantageous in a forensic context to determine small changes in hydrogen concentrations. Neutron radiography of decaying canine tissues was performed to evaluate the PMI by measuring the changes in H content. In this study, dog cadavers were used as a model for human cadavers. Canine tissues and cadavers were exposed to controlled (laboratory settings, at the University of Tennessee, College of Veterinary Medicine) and uncontrolled (University of Tennessee Anthropology Research Facility) environmental conditions, respectively. Neutron radiographs were supplemented with photographs and histology data to assess the decompositional stages of cadavers. Results demonstrated that the increase in neutron transmission likely corresponded to a decrease in hydrogen content in the tissue, which was correlated with the decay time of the tissue. Tissues depleted in hydrogen were brighter in the neutron transmission radiographs of skeletal muscles, lung, and bone, under controlled conditions. Over a period of 10 days, changes in neutron transmission through lung and muscle were found to be higher than bone by 8.3%, 7.0%, and 2.0%, respectively. Results measured during uncontrolled conditions were more difficult to assess and further studies are necessary. In conclusion, neutron radiography may be used to detect changes in hydrogen abundance that can be correlated with the post-mortem interval.

BCL-2 family protein, BAD is down-regulated in breast cancer and inhibits cell invasion

We have previously demonstrated that the anti-apoptotic protein BAD is expressed in normal human breast tissue and shown that BAD inhibits expression of cyclin D1 to delay cell-cycle progression in breast cancer cells. Herein, expression of proteins in breast tissues was studied by immunohistochemistry and results were analyzed statistically to obtain semi-quantitative data. Biochemical and functional changes in BAD-overexpressing MCF7 breast cancer cells were evaluated using PCR, reporter assays, western blotting, ELISA and extracellular matrix invasion assays. Compared to normal tissues, Grade II breast cancers expressed low total/phosphorylated forms of BAD in both cytoplasmic and nuclear compartments. BAD overexpression decreased the expression of β-catenin, Sp1, and phosphorylation of STATs. BAD inhibited Ras/MEK/ERK and JNK signaling pathways, without affecting the p38 signaling pathway. Expression of the metastasis-related proteins, MMP10, VEGF, SNAIL, CXCR4, E-cadherin and TlMP2 was regulated by BAD with concomitant inhibition of extracellular matrix invasion. Inhibition of BAD by siRNA increased invasion and Akt/p-Akt levels. Clinical data and the results herein suggest that in addition to the effect on apoptosis, BAD conveys anti-metastatic effects and is a valuable prognostic marker in breast cancer.

Piroxicam inhibits Masitinib-induced cyclooxygenase 2 expression in oral squamous cell carcinoma cells in vitro

Development and characterization of animal models for human cancers is important for the improvement of diagnosis and therapy. The oral squamous cell carcinoma (OSCC) of domestic animals resembles human OSCC in many aspects; thus, cell lines derived from OSCC of cats and dogs are a valuable model for human OSCC. We characterized 1 feline OSCC (FeOSCC-Sidney) and 1 canine OSCC (K9OSCC-Abby) cell line and compared their characteristics with human OSCC cell line hSCC-25. We calculated the doubling time of the new OSCC cell lines and evaluated the expression profiles of cancer-related markers and cell-cycle proteins such as c-kit, platelet-derived growth factor receptor, vascular endothelial growth factor receptor, epidermal growth factor receptor, cyclooxygenase (COX)-1, COX-2, and p27 by immunocytochemistry and Western blot analysis. We evaluated the effects of novel receptor tyrosine kinase inhibitor (Masitinib, AB1010) and the nonsteroidal anti-inflammatory drug piroxicam on the previously mentioned OSCC cells. Interestingly, AB1010 increased expression levels of COX-2 in all tested OSCCs. Cotreatment of piroxicam with Masitinib significantly inhibited cell proliferation of OSCC as compared to either drug alone through the c-kit and AKT signaling pathways. Piroxicam inhibited Masitinib-induced COX-2 expression in all tested OSCCs. Therefore, targeting these two signaling pathways simultaneously was more efficient for inhibition of OSCCs across these species.

Modulation of adipose tissue inflammation by bioactive food compounds

Adipose tissue has an important endocrine function in the regulation of whole-body metabolism. Obesity leads to a chronic low-grade inflammation of the adipose tissue, which disrupts this endocrine function and results in metabolic derangements, such as type-2 diabetes. Dietary bioactive compounds, such as polyphenols and certain fatty acids, are known to suppress both systemic and adipose tissue inflammation and have the potential to improve these obesity-associated metabolic disorders. Mechanistically, polyphenolic compounds including non-flavonoids, such as curcumin and resveratrol, and flavonoids, such as catechins (tea-polyphenols), quercetin and isoflavones, suppress nuclear factor-κB (NF-κB) and mitogen-activated protein (MAP) kinases (MAPK) pathways while activating the 5' adenosine monophosphate-activated protein kinase (AMPK) pathway in adipose tissue. Dietary polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), conjugated linoleic acid (CLA) and monounsaturated fatty acids (MUFA), such as oleic acid, also impart anti-inflammatory effects through several mechanisms. These include activation of AMPK and peroxisome proliferator-activated receptor gamma (PPAR-γ), as well as suppression of toll-like receptors (TLRs) and NF-κB pathway. This review discusses the major molecular mechanisms of dietary polyphenols and fatty acids, alone or in combination, which are responsible for adipose tissue-associated anti-inflammatory effects.

Molecular imaging of cyclooxygenase-2 in canine transitional cell carcinomas in vitro and in vivo

The enzyme COX-2 is induced at high levels in tumors but not in surrounding normal tissues, which makes it an attractive target for molecular imaging of cancer. We evaluated the ability of novel optical imaging agent, fluorocoxib A to detect urinary bladder canine transitional cell carcinomas (K9TCC). Here, we show that fluorocoxib A uptake overlapped with COX-2 expression in primary K9TCC cells in vitro. Using subcutaneously implanted primary K9TCC in athymic mice, we show specific uptake of fluorocoxib A by COX-2-expressing K9TCC xenograft tumors in vivo. Fluorocoxib A uptake by COX-2-expressing xenograft tumors was blocked by 70% (P < 0.005) when pretreated with the COX-2 selective inhibitor, celecoxib (10 mg/kg), 4 hours before intravenous administration of fluorocoxib A (1 mg/kg). Fluorocoxib A was taken up by COX-2-expressing tumors but not by COX-2-negative human UMUC-3 xenograft tumors. UMUC-3 xenograft tumors with no expression of COX-2 showed no uptake of fluorocoxib A. In addition, fluorocoxib A uptake was evaluated in five dogs diagnosed with TCC. Fluorocoxib A specifically detected COX-2-expressing K9TCC during cystoscopy in vivo but was not detected in normal urothelium. Taken together, our findings show that fluorocoxib A selectively bound to COX-2-expressing primary K9TCC cells in vitro, COX-2-expressing K9TCC xenografts tumors in nude mice, and heterogeneous canine TCC during cystoscopy in vivo. Spontaneous cancers in companion animals offer a unique translational model for evaluation of novel imaging and therapeutic agents using primary cancer cells in vitro and in heterogeneous cancers in vivo.

Single-dose safety and pharmacokinetic evaluation of fluorocoxib A: pilot study of novel cyclooxygenase-2-targeted optical imaging agent in a canine model

We evaluated preclinical single-dose safety, pharmacokinetic properties, and specific uptake of the new optical imaging agent fluorocoxib A in dogs. Fluorocoxib A, N-[(5-carboxy-X-rhodaminyl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide, selectively binds and inhibits the cyclooxygenase-2 (COX-2) enzyme, which is overexpressed in many cancers. Safety pilot studies were performed in research dogs following intravenous (i.v.) administration of 0.1 and 1  mg/kg fluorocoxib A. Blood and urine samples collected three days after administration of each dose of fluorocoxib A revealed no evidence of toxicity, and no clinically relevant adverse events were noted on physical examination of exposed dogs over that time period. Pharmacokinetic parameters were assessed in additional research dogs from plasma collected at several time points after i.v. administration of fluorocoxib A using high-performance liquid chromatography analysis. The pharmacokinetic studies using 1  mg/kg showed a peak of fluorocoxib A (92±28  ng/ml) in plasma collected at 0.5 h. Tumor specific uptake of fluorocoxib A was demonstrated using a dog diagnosed with colorectal cancer expressing COX-2. Our data support the safe single-dose administration and in vivo efficacy of fluorocoxib A, suggesting a high potential for successful translation to clinical use as an imaging agent for improved tumor detection in humans.

Abstract CN04-02: A novel approach to biomolecular imaging of COX-2

Molecular imaging emerged in the early 21st century as a discipline that enables the visualization of cellular functions, molecular biology of diseases, and diagnosis of disease states in living beings. COX-2 is an attractive target for molecular imaging of cancer, because it is an inducible enzyme that is expressed in inflammation, premalignant and malignant lesions. We designed fluorescent COX-2 inhibitors by tethering bulky fluorescent functional groups onto non-steroidal anti-inflammatory drugs (NSAIDs), and COX-2 inhibitors (COXIBs). To identify the lead compounds, we synthesized a library of 200 hundred fluorescent conjugates, and evaluated them for selective inhibition of purified COX-2, COX-2 in mouse macrophages and COX-2 in human cancer cells. Although a significant number of compounds showed COX-2 inhibitory activity against purified protein, only a fraction of these compounds inhibited COX-2 activity in intact cells, and of those, most did not possess fluorescence properties suitable for in vivo imaging. Optimized lead compounds were then tested for their ability to image COX-2 in intact cells. Among the compounds that emerged from our development pathway, only 5-carboxy-X-rhodamine (5-ROX) and 6-carboxy-X-rhodamine (6-ROX) based conjugates, Fluorocoxib A and Fluorocoxib B, exhibited sufficient metabolic stability to distribute to target tissues in rodents and canines. A detailed kinetic analysis indicated that these compounds are slow, tight-binding inhibitors of COX-2 with very low rates of association and dissociation. These compounds displayed a very high degree of selectivity of uptake in inflammatory tissues or human tumor xenografts in rodents, and in naturally occurring oral or bladder cancer in dogs relative to surrounding normal tissue or muscle as determined by either optical imaging or mass spectrometry. Uptake of these compounds required the expression of COX-2 at the target site and declined as the level of COX-2 decreased. Experiments with COX-2 (-/-) animals or with animals pretreated with indomethacin or celecoxib verified that selective accumulation into inflamed tissue or tumors was due to binding to COX-2. Pharmacokinetic analysis revealed that only the intact parent compound is found in the region of interest. Site-directed mutagenesis and analysis of X-ray co-crystal structure of fluorocoxib A with COX-2 revealed that the n-butyl linker group allows the indomethacin part of fluorocoxib A to fully insert into the binding pocket of COX-2, while the bulky fluorescent 5-ROX group binds in the lobby of the enzyme. Thus, fluorocoxibs represent the first feasible optical imaging reagents for clinical detection of tissues containing high levels of COX-2 in settings amenable to fluorescent excitation and analysis by surface measurement or endoscopy (e.g., skin, esophagus, intestine, and bladder).

(This work has been supported by grants from the National Cancer Institute and National Institutes of Health [CA136465 and CA128323])

Citation Format: Md. Jashim Uddin, Brenda C. Crews, Kebreab Ghebreselasie, Anna L. Blobaum, Kelsey C. Duggan, Shu Xu, Philip Kingsley, Maria Cekanova, Lawrence J. Marnett. A novel approach to biomolecular imaging of COX-2. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr CN04-02.

P1-02-11: The BCL2 Antagonist of Death, BAD Is Down-Regulated in Breast Cancer and Inhibits Cancer Cell Invasion

Background: Recent clinical evidence suggest that expression of BCL2 and its antagonist BAD are good prognosticators for survival in breast cancer patients. BAD protein was previously shown by us to inhibit cyclin D1 expression and cJun activation, both may enhance invasiveness of tumor cells(Fernando et al JBC 07). However, the role of BAD and other BCL2 family proteins in invasion/metastasis of breast cancer is poorly characterized.

Methods: By immunohistochemistry nuclear and cytoplasmic staining of several proteins including BAD in normal epithelial was compared to that of cancer cells in human specimens. Western blotting and ELISA methods were used to compare BAD overexpressing MCF7 breast cancer cells with control cells for the expression of variety of signaling molecules, proteins that take part in metastasis and invasion and ability of cells to invade was measured. PCR was used to measure m RNA levels and reporter constructs utilized for transcriptional factor activity studies.

Results: Grade II breast cancer specimens express less total and phosphorylated forms of BAD in nuclei and cytoplasm compared to normals. BAD expression decreased Sp1, β-catenin and STAT proteins, which may increase cyclin D1 in vitro. BAD inhibited activation of the CRE and AP1 elements, and phosphorylation of BAD on S112 and S136 is required for this activity. BAD inhibited the Ras/MEK/ERK pathway and JNK, which may underlie inactivation of c Jun. BAD, like BCL2, may decrease metastasis,therefore, ability of BAD to modulate the expression of metastasis related proteins were measured and MMP10, VEGF, SNAIL, CXCR4, E-cadherin, and ***TlMP2 were regulated by BAD with a concomitant reduction in cell invasion.

Conclusion: Higher expression of BAD in breast cancer and a role in metastasis and proliferation suggests that BAD is valuable prognostic marker in breast cancer and a multi functional protein. Further given the overwhelming clinical evidence that BCL2 prolongs survival, a reevaluation of the role of BCL2 family proteins in metastasis is urgently required.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-02-11.

Abstract 1046: BAD is a multifunctional protein in breast cancer cells

BAD is a multifunctional protein in breast cancer cells R. Fernando1, M. Cekanova2, J. Woraratphoka2, M. Sukhthankar2, J. Bahn2, S. Dharmawardhana3, N. Siriwardana2, N. Moustaid-Moussa2, A. Strom4, S. Baek2, Q. Wong5, M. Zou5, R. Donnell2, J. Wimalasena2

1NCI, Bethesda, MD; 2University of Tennessee, Knoxville, TN; 3University of Puerto Rico Medical Sciences, San Juan, PR; 4University of Houston, Houston, TX; 5University of Oklahoma Medical Center, Oklahoma City, OK.

BAD is a typical BH3 protein and, like many other BCL-2 family proteins, regulates apoptosis. However, several recent studies suggest that BAD has non-apoptotic roles. Previously, we had shown that BAD inhibits the MCF7 cell cycle via abrogation of cyclin D1 synthesis (JBC 282, 28864, 2007). Using tetracycline-regulated stable BAD overexpression in MCF7 cells, we now report that BAD regulates a wide variety of functions: since BAD binds to c-Jun (JBC, 2007), we investigated the ability of BAD to regulate the AP1 reporter activity. BAD inhibited MEK and activated RAS (V12, S35) regulated AP1 activity, but not the increase due to AKT. BAD overexpression blocked ERK activation by MEK1, but not by active AKT. Wildtype BAD inhibited estrogen- or serum-induced activation of c-Jun, JNK, and ERK, but not p38 MAPK. However, the S112/S136 double mutant BAD had no inhibitory effects, suggesting a requirement for phosphorylation. We then explored if BAD can regulate signaling pathways and found that it can inhibit beta catenin mRNA and protein expression. Several signaling proteins, including total AKT, active GSK 3 beta, and apoptosis-related soluble FasL, TNF alpha, TRAIL, EGFR, and RBM5, which may regulate FasL were significantly (p&lt;0.01) regulated by BAD. BAD decreased invasion of MCF7 cells through Matrigel (p&lt;0.05) and decreased cellular VEGF (p50% (p&lt;0.01). Surprisingly, BAD decreased protein expression of PPAR gamma, active AMPK, LKB1, and active acetylCoA carboxylase (all at p&lt;0.01). We analyzed the expression of several markers in breast cancer specimens: phospho (p)-BAD, BAD and cyclin D1 using tissue microarrays containing normal and neoplastic tissue. In addition, we checked the expression levels of ERK-1, phospho (p)-ERK1, AKT, and phospho-AKT in surgical pathology blocks with normal and neoplastic breast epithelial cells. As expected, cytoplasmic p-BAD expression was significantly and positively correlated with nuclear BAD, nuclear p-BAD, as well as nuclear cyclin D1. Our data showed that cytoplasmic cyclin D1 was positively correlated with cytoplasmic ERK-1, and cytoplasmic cyclin D1 was negatively correlated with nuclear AKT expression. Nuclear BAD and AKT were negatively correlated with nuclear cyclin D1 and nuclear ER-beta. Cytoplasmic expression of p-ERK1 was negatively correlated with nuclear AKT and positively correlated with nuclear cyclin D1, and nuclear ER-beta.

Taken together, these results suggest that BAD may be a multifunctional protein.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1046.

Abstract 4591: Estrogen receptor beta controls a wide variety of functions in breast cancer cells

The role of ER alpha as the mediator of estrogen action in breast cancer (BC) cells is well known, however, the role of ER beta is controversial. The majority of BC expressing ER alpha also express ER beta. Some clinical studies suggest that ER beta expression is a good prognosticator; however, in others, especially where expression levels of ER beta &gt; ER alpha, ER beta may be associated with more advanced BC. Previously, we showed that ER beta may regulate a number of signaling pathways (AACR, 2008). Our recent work demonstrates that ER beta has even wider actions in MCF7 and T47D cells stably overexpressing ER beta. Thus, ER beta decreased phospho (p)/ total Stat1, p Stat3, p Stat5/total Stat5. Expression of the oncogenic miR cluster 17-92 was highly reduced (p&lt;0.01) when ER beta overexpressing vs. control cells were compared. ER beta also decreased PPAR gamma, superoxide dismutase, as well as the concentration of the mRNA processing factor, RBM5, and the activated form of AMPK. All these changes were significant (p&lt;0.05) in triplicate measurements. While ER beta overexpression increased migration through Matrigel, it significantly decreased CXCR4 expression (p&lt;0.05, n=4). All of these effects of ER beta were estrogen-independent. On the other hand, estrogen increased CXCR4 expression in MCF7 cells significantly. In our study, we analyzed the expression of ER beta and BAD using tissue microarrays with normal and neoplastic breast tissue. Our immunohistochemical (IHC) data revealed a significant increase of ER beta cytoplasmic staining in neoplastic cells compared to normal cells (p&lt;0.001). In addition, the nuclear expression of ER beta was significantly decreased in neoplastic cells compared to normal cells (p&lt;0.01). From our correlation analysis of IHC data obtained from tissue microarray, we identified that cytoplasmic expression of BAD was negatively correlated with cytoplasmic expression of ER beta. In addition, the nuclear expression of BAD was significantly positively correlated with nuclear ER beta.

These results suggest that ER beta has a wide variety of actions in BC cells, as predicted by the regulation of 62 miRs (p&lt;0.01) as determined by Exiqon Inc. Taken together our results suggest that ER beta may have a multitude of actions in breast cancer and that the ratio of ER alpha/beta may determine the prognostic outcome.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4591.

MCC-555-induced NAG-1 expression is mediated in part by KLF4

Peroxisome proliferator-activated receptor gamma (PPARgamma) plays a central role in cell differentiation, metabolism and tumorigenesis. We have investigated the therapeutic properties of 5-[[6-[(2-fluorophenyl)-methoxy]-2-napthalenyl]-methyl]-2,4-thiazolidinedione (MCC-555) a PPARgamma agonist in human colorectal cancer cells. To elucidate the molecular mechanism(s), by which MCC-555 exerts its effects on the human colorectal cancer cells, we have analyzed the expression of two pro-apoptotic proteins, Krüppel-like factor 4 (KLF4) and nonsteroidal anti-inflammatory drug (NSAID)-activated gene-1 (NAG-1). MCC-555-induced expression of the transcription factor, KLF-4 was blocked by a PPARgamma specific antagonist GW9662 in PPARgamma-dependent manner in HCT-116 cells. We further identified a new KLF4 target gene NAG-1, which shows a pro-apoptotic activity. We confirmed that PPARgamma agonists-induced NAG-1 expression was abolished using KLF4 siRNA in HCT-116 cells. Subsequently, KLF4 expression enhances the NAG-1 promoter activity in HCT-116 cells, and functional KLF4 binding sites in the NAG-1 promoter were also identified. MCC-555, a PPARgamma agonist induced the expression of Klf4 mRNA and protein in murine intestinal tumors from MCC-555-treated mice, as assessed by RT-PCR and immunohistochemistry. This study shows that PPARgamma agonists up-regulate KLF4 expression in receptor-dependent manner, and KLF4 was identified as a novel transcription factor that controls NAG-1 promoter activity in human and mouse colorectal cancers.

Nonsteroidal anti-inflammatory drug-activated gene-1 expression inhibits urethane-induced pulmonary tumorigenesis in transgenic mice

The expression of nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1) inhibits gastrointestinal tumorigenesis in NAG-1 transgenic mice (C57/BL6 background). In the present study, we investigated whether the NAG-1 protein would alter urethane-induced pulmonary lesions in NAG-1 transgenic mice on an FVB background (NAG-1(Tg+/FVB)). NAG-1(Tg+/FVB) mice had both decreased number and size of urethane-induced tumors, compared with control littermates (NAG-1(Tg+/FVB) = 16 +/- 4 per mouse versus control = 20 +/- 7 per mouse, P < 0.05). Urethane-induced pulmonary adenomas and adenocarcinomas were observed in control mice; however, only pulmonary adenomas were observed in NAG-1(Tg+/FVB) mice. Urethane-induced tumors from control littermates and NAG-1(Tg+/FVB) mice highly expressed proteins in the arachidonic acid pathway (cyclooxygenases 1/2, prostaglandin E synthase, and prostaglandin E(2) receptor) and highly activated several kinases (phospho-Raf-1 and phosphorylated extracellular signal-regulated kinase 1/2). However, only urethane-induced p38 mitogen-activated protein kinase (MAPK) phosphorylation was decreased in NAG-1(Tg+/FVB) mice. Furthermore, significantly increased apoptosis in tumors of NAG-1(Tg+/FVB) mice compared with control mice was observed as assessed by caspase-3/7 activity. In addition, fewer inflammatory cells were observed in the lung tissue isolated from urethane-treated NAG-1(Tg+/FVB) mice compared with control mice. These results paralleled in vitro assays using human A549 pulmonary carcinoma cells. Less phosphorylated p38 MAPK was observed in cells overexpressing NAG-1 compared with control cells. Overall, our study revealed for the first time that the NAG-1 protein inhibits urethane-induced tumor formation, probably mediated by the p38 MAPK pathway, and is a possible new target for lung cancer chemoprevention.

Peroxisome proliferator-activated receptor ligand MCC-555 suppresses intestinal polyps in ApcMin/+ mice via extracellular signal-regulated kinase and peroxisome proliferator-activated receptor-dependent pathways

A large body of studies has suggested that peroxisome proliferator-activated receptor gamma (PPARgamma) ligands, such as thiazolidinedione, are potent candidates for chemopreventive agents. MCC-555 is a PPARgamma/alpha dual agonist and has been shown previously to induce apoptosis in vitro; however, the molecular mechanisms by which MCC-555 affects antitumorigenesis in vivo are poorly understood. In this study, we explored the antitumorigenic effects of MCC-555 both in cell culture and in Apc-deficient mice, an animal model for human familial adenomatous polyposis. MCC-555 increased MUC2 expression in colorectal and lung cancer cells, and treatment with the PPARgamma antagonist GW9662 revealed that MUC2 induction by MCC-555 was mediated in a PPARgamma-dependent manner. Moreover, MCC-555 increased transcriptional activity of human and mouse MUC2 promoters. Subsequently, treatment with MCC-555 (30 mg/kg/d) for 4 weeks reduced the number of small intestinal polyps to 54.8% of that in control mice. In agreement with in vitro studies, enhanced Muc2 expression was observed in the small intestinal tumors of Min mice treated with MCC-555, suggesting that MUC2 expression may be associated at least in part with the antitumorigenic action of MCC-555. In addition, highly phosphorylated extracellular signal-regulated kinase (ERK) was found in the intestinal tumors of MCC-555-treated Min mice, and inhibition of the ERK pathway by a specific inhibitor markedly suppressed MCC-555-induced Muc2 expression in vitro. Overall, these results indicate that MCC-555 has a potent tumor suppressor activity in intestinal tumorigenesis, likely involving MUC2 up-regulation by ERK and PPARgamma pathways.

Gene alterations by peroxisome proliferator-activated receptor gamma agonists in human colorectal cancer cells

The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear transcription factor that controls the genes involved in metabolism and carcinogenesis. In the present study, we examined the alteration of gene expression in HCT-116 human colorectal cancer cells by PPARgamma agonists: MCC-555 (5 microM), rosiglitazone (5 microM), and 15-deoxy-Delta12,14-prostaglandin J2 (1 microM). The long-oligo microarray data revealed a list of target genes commonly induced (307 genes) and repressed (32 genes) by tested PPARgamma agonists. These genes were analyzed by Onto-Express software and KEGG pathway analysis and revealed that PPARgamma agonists are involved in cell proliferation, focal adhesion, and several signaling pathways. Eight genes were selected to confirm the microarray data by RT-PCR and real-time PCR, from which CSTA, DAP13, TAF12, RIS1, CDKN3 and MAGOH were up-regulated, and KLHL11 and NCOA2 were down-regulated. This study elucidates the commonly induced genes modulated by tested PPARgamma ligands involved in the different signaling pathways and metabolisms, probably mediated in a PPARgamma-dependent manner in colorectal cancer cells and helps to better understand the pleiotropic actions of PPARgamma ligands.

Multiple mechanisms are involved in 6-gingerol-induced cell growth arrest and apoptosis in human colorectal cancer cells

6-Gingerol, a natural product of ginger, has been known to possess anti-tumorigenic and pro-apoptotic activities. However, the mechanisms by which it prevents cancer are not well understood in human colorectal cancer. Cyclin D1 is a proto-oncogene that is overexpressed in many cancers and plays a role in cell proliferation through activation by beta-catenin signaling. Nonsteroidal anti-inflammatory drug (NSAID)-activated gene-1 (NAG-1) is a cytokine associated with pro-apoptotic and anti-tumorigenic properties. In the present study, we examined whether 6-gingerol influences cyclin D1 and NAG-1 expression and determined the mechanisms by which 6-gingerol affects the growth of human colorectal cancer cells in vitro. 6-Gingerol treatment suppressed cell proliferation and induced apoptosis and G(1) cell cycle arrest. Subsequently, 6-gingerol suppressed cyclin D1 expression and induced NAG-1 expression. Cyclin D1 suppression was related to inhibition of beta-catenin translocation and cyclin D1 proteolysis. Furthermore, experiments using inhibitors and siRNA transfection confirm the involvement of the PKCepsilon and glycogen synthase kinase (GSK)-3beta pathways in 6-gingerol-induced NAG-1 expression. The results suggest that 6-gingerol stimulates apoptosis through upregulation of NAG-1 and G(1) cell cycle arrest through downregulation of cyclin D1. Multiple mechanisms appear to be involved in 6-gingerol action, including protein degradation as well as beta-catenin, PKCepsilon, and GSK-3beta pathways.

Breast cancer cell proliferation is inhibited by BAD: regulation of cyclin D1

Recent investigations suggest that functions of the proapoptotic BCL2 family members, including BAD, are not limited to regulation of apoptosis. Here we demonstrate that BAD inhibits G(1) to S phase transition in MCF7 breast cancer cells independent of apoptosis. BAD overexpression inhibited G(1) transit and cell growth as well as cyclin D1 expression. Inhibition of cyclin D1 expression was mediated through inhibition of transcription activated by AP1. Chromatin immunoprecipitation assays indicated that BAD is localized at the 12-O-tetradecanoylphorbol-13-acetate-response element (TRE) and cAMP-response element (CRE) in the cyclin D1 promoter. This was shown to reflect direct binding interactions of BAD with c-Jun, and this interaction inhibited the activity of AP1 complexes at TRE. BAD did not interact with phosphorylated forms of c-Jun. Our data suggest that inhibitory TRE/CRE-c-Jun-BAD complexes are present at the cyclin D1 promoter in quiescent cells. Estrogen stimulation displaced BAD from TRE/CRE elements in MCF7 cells, whereas BAD overexpression inhibited estrogen-induced cyclin D1 synthesis and cell proliferation. Inhibition of endogenous BAD in MCF7 cells markedly increased the proliferative fraction and DNA synthesis, activated Cdks, and increased cyclin D1 protein levels. This action of BAD required serine residues Ser(75) and Ser(99). Both phosphorylated and unphosphorylated forms of BAD localized to the nuclei of human breast epithelial cells. Thus, we demonstrate a novel role for BAD in cell cycle regulation dependent upon its phosphorylation state and independent of the BAD/BCL2 interaction and apoptosis.

Overexpressed Raf-1 and phosphorylated cyclic adenosine 3′-5′-monophosphatate response element-binding protein are early markers for lung adenocarcinoma

BACKGROUND

Pulmonary adenocarcinoma (PAC) is the leading type of lung cancer and has a high mortality. The tobacco carcinogen nicotine-derived nitrosamine 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) stimulates the proliferation of human PAC cells and small airway epithelial cells through beta-1 adrenorecptor-mediated transactivation of the epidermal growth factor receptor (EGFR).

METHODS

Using the NNK hamster PAC model and human PAC tissue arrays with matched and unmatched normal lung tissues, the authors tested the hypothesis that Raf-1, an effector of the EGFR, and P-CREB, an effector of the beta-adrenoreceptor, are overexpressed in a significant subset of human PACs and are early markers of PAC development. Western blots from respiratory epithelial cells and microadenomas harvested by laser-capture microdissection from hamster lungs accompanied by immunostains were used to monitor the expression levels of Raf-1 and P-CREB after 5 weeks, 10 weeks, and 20 weeks of NNK treatment. Expression levels of these markers in human PAC tissue arrays were assessed by immunostains. Reverse-phase proteomics, Western blot analysis, and immunoprecipitation in immortalized human small-airway epithelial cells and in a human PAC cell line in the presence and absence of dominant-negative Raf were used to determine Raf dependence of extracellular signal-regulated kinase 1 and 2 (ERK1/2) activation in response to NNK or isoproterenol.

RESULTS

The data showed a time-dependent increase in the expression of Raf-1 and P-CREB after NNK treatment in small-airway epithelial cells and microadenomas of hamsters. The majority of human lung adenocarcinomas simultaneously overexpressed Raf-1 and P-CREB. Dominant-negative Raf completely abrogated ERK1/2 activation by NNK and isoproterenol.

CONCLUSIONS

The current results indicated that RAF-1 and P-CREB may contribute to the development of a significant subset of human lung adenocarcinomas and may offer promising targets for early detection and treatment.

Detection of overexpressed COX-2 in precancerous lesions of hamster pancreas and lungs by molecular imaging: implications for early diagnosis and prevention

The enzyme cyclooxygenase-2 (COX-2) is overexpressed in many cancers, cardiovascular disease, neurodegenerative disorders, and arthritis. Selective inhibitors of COX-2 have been developed as therapeutics or preventive agents for these diseases. However, recent reports have revealed a significant increase in cardiovascular mortality in long-term users of the COX-2 inhibitors Vioxx and Celebrex, emphasizing the need for noninvasive tests that allow the identification of individuals whose COX-2 levels are overexpressed prior to assignment to treatment with these drugs. In this study, we have prepared a radioiodinated analogue of the selective COX-2 inhibitor celecoxib, and verified its binding to the COX-2 enzyme in vitro. Biodistribution studies in hamsters demonstrated significantly higher levels of radiotracer in animals treated with the tobacco carcinogen NNK in lung, pancreas, and liver. Assessment of COX-2 levels by whole-body planar nuclear imaging two hours after injection of the radiotracer was suggestive of a distinct increase in COX-2 in the pancreas and liver of a hamster treated for 10 weeks with NNK, in the lungs and liver of a second animal, and in the liver only, in two additional animals from the same treatment group. Immunostains showed selective overexpression of COX-2 in pre-neoplastic lesions of the pancreas and lungs in only those animals that showed tracer accumulation in these organs and in the livers of all NNK-treated hamsters. Immunostains for COX-1 yielded detectable reactions in the intestinal epithelium but not in pancreas, lungs, or liver, supporting the specificity of the tracer for COX-2. Our data provide proof of principle for the hypothesis that molecular imaging with radiolabeled COX-2 inhibitors can be used for the noninvasive monitoring of overexpressed COX-2 levels.

NNK activates ERK1/2 and CREB/ATF-1 via beta-1-AR and EGFR signaling in human lung adenocarcinoma and small airway epithelial cells

We have shown that the tobacco nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is an agonist for -adrenergic receptors (beta-ARs) and increased DNA synthesis of human lung adenocarcinoma cells with features of bronchiolar Clara cells by binding to these receptors. Using a cell line derived from a human pulmonary adenocarcinoma with Clara cell phenotype (PACC) and immortalized human small airway epithelial cells (HPLD1), the putative cells of origin of this cancer type, our current studies have analyzed signaling initiated by binding of NNK to the beta 1-AR. NNK upregulated ERK1/2 and CREB/ATF-1 phosphorylation in a PKA-dependent manner in both cell lines. This response was further increased by transient overexpression of the beta 1-AR. Pre-exposure of cells to the selective beta 1-AR antagonist, atenolol, attenuated the stimulatory effects of NNK, suggesting the latter upregulated ERK1/2 and CREB/ATF-1 via this receptor. In vivo labeling and immunoprecipitation assays revealed that NNK phosphorylated the epidermal growth factor receptor (EGFR) at tyrosine residues, 991, 1068 and 1173, an effect inhibited by atenolol. The inhibitor of EGFR-specific tyrosine kinases, AG1478, reduced NNK ability to stimulate ERK1/2 and CREB/ATF-1. Genomic analysis of the exons 18-21 of the EGFR genes showed that no mutations were present in either gene. Collectively, our data provide evidence, for the first time, that NNK targets ERK1/2 and CREB/ATF-1 proteins via dual signaling involving beta 1-AR and EGFR pathways in PACCs and their putative cells of origin.

Pulmonary fibroblasts stimulate the proliferation of cell lines from human lung adenocarcinomas

Human lung cancer cell lines are widely used to test anticancer drugs. These in-vitro tests, however, preclude the detection of responses to paracrine factors from surrounding stroma. We have cocultured pulmonary fibroblasts CCD-19Lu, from a healthy donor, or HLF-A, from a patient with epidermoid carcinoma of the lung, with two human pulmonary adenocarcinoma cell lines to test the hypothesis that the fibroblasts stimulate the growth of the tumor cells. Both fibroblast cell lines significantly increased the proliferation of the pulmonary adenocarcinoma cell lines in 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide assays, with HLF-A fibroblasts yielding the most pronounced responses. The proliferation of the pulmonary adenocarcinoma cell lines in coculture with fibroblasts was blocked by antibodies against the transforming growth factor-alpha and amphiregulin. In addition, reverse transcription-polymerase chain reaction showed expression of mRNA for amphiregulin and transforming growth factor-alpha in all cell lines, whereas mRNA for the epidermal growth factor was detected only in pulmonary adenocarcinoma cell lines. Western blot analysis revealed that medium containing growth factors released by each fibroblast cell line activated extracellular signal-regulated kinase 1/2 in the both tested pulmonary adenocarcinoma cell lines, but activated Akt kinase only in A549 cells. Assessment of protein levels for cyclin D1 and cyclin E by Western blots demonstrated pronounced increases of both proteins in each pulmonary adenocarcinoma cell line, whereas protein levels for cyclin-dependent kinase inhibitor p21 remained unchanged. Immunocytochemical analysis showed positive immunoreactivity for P-extracellular signal-regulated kinase 1/2, cyclin D1 and cyclin E in pulmonary adenocarcinoma cells cocultured with fibroblasts or exposed to fibroblast-conditioned media. Our data suggest that the growth of pulmonary adenocarcinoma is stimulated by amphiregulin and transforming growth factor-alpha released from pulmonary fibroblasts. This may contribute to the disappointing clinical responses to anticancer drugs, which have shown promise in tests with lung cancer cell lines.

Ethanol and the tobacco-specific carcinogen, NNK, contribute to signaling in immortalized human pancreatic duct epithelial cells

OBJECTIVES

Smoking is a well-documented risk factor for pancreatic cancer. The tobacco-specific nitrosamine, NNK (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone), significantly induces pancreatic ductal adenocarcinomas in laboratory rodents. Recent observations suggest that ethanol enhances the tumorigenic effects of smoking. Ethanol consumption is associated with the development of chronic pancreatitis, also considered a predisposing factor for pancreatic ductal adenocarcinoma. Because the precise role of ethanol in pancreatic carcinogenesis is not known, this study sought to elucidate the cumulative effects of ethanol and NNK on particular signal transduction pathways that might play a role in cell proliferation in immortalized human pancreatic duct epithelial cells.

METHODS

The HPDE6-c7 cells are developed from pancreatic duct epithelial cells, which are the putative cells of origin of pancreatic ductal adenocarcinoma. Cell proliferation assays, Western blot, and cyclic adenosine monophosphate assays were used to demonstrate the effects of ethanol and NNK treatments on these cells.

RESULTS

Ethanol cotreatments enhanced the NNK-induced proliferation of these cells. This response was inhibited by the adenylyl cyclase, protein kinase A, mitogen-activated protein kinase (p42/p44), and epidermal growth factor receptor-specific tyrosine kinase inhibitors. Cotreatments of NNK and ethanol also increased cyclic adenosine monophosphate accumulation, cAMP response element-binding family of proteins and mitogen-activated protein kinase phosphorylation, and protein kinase A activation.

CONCLUSIONS

These findings suggest a potential role for these pathways contributing to the development of smoking- and alcohol-related pancreatic carcinogenesis.

Detection of overexpressed COX-2 in precancerous lesions of hamster pancreas and lungs by molecular imaging: implications for early diagnosis and prevention

The enzyme cyclooxygenase-2 (COX-2) is overexpressed in many cancers, cardiovascular disease, neurodegenerative disorders, and arthritis. Selective inhibitors of COX-2 have been developed as therapeutics or preventive agents for these diseases. However, recent reports have revealed a significant increase in cardiovascular mortality in long-term users of the COX-2 inhibitors Vioxx and Celebrex, emphasizing the need for noninvasive tests that allow the identification of individuals whose COX-2 levels are overexpressed prior to assignment to treatment with these drugs. In this study, we have prepared a radioiodinated analogue of the selective COX-2 inhibitor celecoxib, and verified its binding to the COX-2 enzyme in vitro. Biodistribution studies in hamsters demonstrated significantly higher levels of radiotracer in animals treated with the tobacco carcinogen NNK in lung, pancreas, and liver. Assessment of COX-2 levels by whole-body planar nuclear imaging two hours after injection of the radiotracer was suggestive of a distinct increase in COX-2 in the pancreas and liver of a hamster treated for 10 weeks with NNK, in the lungs and liver of a second animal, and in the liver only, in two additional animals from the same treatment group. Immunostains showed selective overexpression of COX-2 in pre-neoplastic lesions of the pancreas and lungs in only those animals that showed tracer accumulation in these organs and in the livers of all NNK-treated hamsters. Immunostains for COX-1 yielded detectable reactions in the intestinal epithelium but not in pancreas, lungs, or liver, supporting the specificity of the tracer for COX-2. Our data provide proof of principle for the hypothesis that molecular imaging with radiolabeled COX-2 inhibitors can be used for the noninvasive monitoring of overexpressed COX-2 levels.

Expression of G-protein inwardly rectifying potassium channels (GIRKs) in lung cancer cell lines

BACKGROUND

Previous data from our laboratory has indicated that there is a functional link between the beta-adrenergic receptor signaling pathway and the G-protein inwardly rectifying potassium channel (GIRK1) in human breast cancer cell lines. We wanted to determine if GIRK channels were expressed in lung cancers and if a similar link exists in lung cancer.

METHODS

GIRK1-4 expression and levels were determined by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR. GIRK protein levels were determined by western blots and cell proliferation was determined by a 5-bromo-2'-deoxyuridine (BrdU) assay.

RESULTS

GIRK1 mRNA was expressed in three of six small cell lung cancer (SCLC) cell lines, and either GIRK2, 3 or 4 mRNA expression was detected in all six SCLC cell lines. Treatment of NCI-H69 with beta2-adrenergic antagonist ICI 118,551 (100 microM) daily for seven days led to slight decreases of GIRK1 mRNA expression levels. Treatment of NCI-H69 with the beta-adrenergic agonist isoproterenol (10 microM) decreased growth rates in these cells. The GIRK inhibitor U50488H (2 microM) also inhibited proliferation, and this decrease was potentiated by isoproterenol. In the SCLC cell lines that demonstrated GIRK1 mRNA expression, we also saw GIRK1 protein expression. We feel these may be important regulatory pathways since no expression of mRNA of the GIRK channels (1 & 2) was found in hamster pulmonary neuroendocrine cells, a suggested cell of origin for SCLC, nor was GIRK1 or 2 expression found in human small airway epithelial cells. GIRK (1,2,3,4) mRNA expression was also seen in A549 adenocarcinoma and NCI-H727 carcinoid cell lines. GIRK1 mRNA expression was not found in tissue samples from adenocarcinoma or squamous cancer patients, nor was it found in NCI-H322 or NCI-H441 adenocarcinoma cell lines. GIRK (1,3,4) mRNA expression was seen in three squamous cell lines, GIRK2 was only expressed in one squamous cell line. However, GIRK1 protein expression was not seen in any non-SCLC cells.

CONCLUSION

We feel that this data may indicate that stimulation of GIRK1 or GIRK2 channels may be important in lung cancer. Stimulation of GIRK channels and beta-adrenergic signaling may activate similar signaling pathways in both SCLC and breast cancer, but lead to different results.

NNK-induced hamster lung adenocarcinomas over-express β2-adrenergic and EGFR signaling pathways

Pulmonary adenocarcinoma (PAC) is the most common type of human lung cancer. A diagnosis of PAC, history of non-smoking and presence of mutations in the EGFR are predictive factors for responsiveness of lung cancer to EGFR-specific tyrosine kinase inhibitors. Unfortunately, less than 50% of PAC cases demonstrate this mutation-based responsiveness. Our immunohistochemical analysis of NNK-induced PAC in hamsters demonstrates the simultaneous over-expression of a beta2-adrenergic receptor pathway, including PKA, cAMP, CREB and phosphorylated CREB and of an EGFR pathway, including over-expression of EGFR-specific phosphorylated tyrosine kinase, Raf-1 and ERK1/2 and their phosphorylated forms. These findings implicate, for the first time, PKA/CREB-mediated signaling in the development and regulation of any type of lung cancer. In light of reports that NNK acts as a beta-adrenergic agonist and that beta-blockers inhibit the growth of PAC of Clara cell lineage in the NNK hamster model and in human cancer cell lines from smokers, our current data suggest transactivation of the EGFR pathway via beta-adrenergic signaling as a novel regulatory mechanism in a subpopulation of PACs in smokers. Taken together, these data point to PKA/CREB as novel targets for the development of cancer therapeutics for PAC patients non-responsive to EGFR-specific tyrosine kinase inhibitors.

Nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced pulmonary adenocarcinomas in Syrian golden hamsters contain beta 2-adrenergic receptor single-nucleotide polymorphisms

Cigarette smoking contributes to the development of lung cancer throughout the world, with cases of pulmonary adenocarcinoma (PAC) the most numerous. Nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which is formed from nicotine, has been demonstrated to cause mutations in genes that affect cell regulation and proliferation. Moreover, NNK has been shown to interact directly with and stimulate beta adrenergic receptor (ADRB) signal transduction pathways. Our goal was to determine whether single-nucleotide polymorphisms (SNPs) in the Adrb2 from PAC tumors were induced in golden hamsters by the injection of NNK. Here we report the cloning and sequencing of Adrb2 clones from either dissected lung tumors from NNK-injected animals or whole-lung tissue from water-injected controls. Both sets of animals contained SNPs; however, we found significantly more SNPs in the Adrb2 from NNK-injected animals than in the controls. The majority of these SNPs were novel, nonsynonymous mutations found in regions of the Adrb2 known to be involved in ligand binding, G-protein coupling, and desensitization/down-regulation. Our data verified the mutagenic effects of NNK as well as demonstrated that this animal model provides an outstanding way of identifying mutations not only in the Adrb2, but also in other genes that may play essential roles in the regulation and growth of pulmonary adenocarcinomas.

Multiple luteinizing hormone receptor (LHR) protein variants, interspecies reactivity of anti-LHR mAb clone 3B5, subcellular localization of LHR in human placenta, pelvic floor and brain, and possible role for LHR in the development of abnormal pregnancy, pelvic floor disorders and Alzheimer's disease

Distinct luteinizing hormone receptor (LHR) protein variants exist due to the posttranslational modifications. Besides ovaries, LHR immunoreactivity (LHRI) was also found in other tissues, such as the brain, fallopian tube, endometrium, trophoblast and resident tissue macrophages. The 3B5 mouse monoclonal antibody was raised against purified rat LHR. In rat, porcine and human ovaries, the 3B5 identified six distinct LHR bands migrating at approximately 92, 80, 68, 59, 52 and 48 kDa. Characteristic LHRI was detected in rat, human and porcine corpora lutea. During cellular differentiation, subcellular LHR distribution changed from none to granular cytoplasmic, perinuclear, surface, nuclear and no staining. There were also differences in vascular LHR expression--lack of LHRI in ovarian vessels and strong staining of vessels in other tissues investigated. In normal human term placentae, villous LHRI was associated with blood sinusoids and cytotrophoblast cells, and rarely detected in trophoblastic syncytium. In all abnormal placentae, the LHRI of sinusoids was absent, and syncytium showed either enhanced (immature placental phenotypes) or no LHRI (aged placental phenotype). LHRI in human brain was identified in microglial cells (CD68+ resident macrophages). Protein extracts from human vaginal wall and levator ani muscle and fascia showed strong approximately 92 and 68 kDa species, and LHRI was detected in smooth muscle cells, fibroblasts, resident macrophages and nuclei of skeletal muscle fibers. Our observations indicate that, in contrast to the theory on the role of vascular hormone receptors in preferential pick up of circulating hormones, there is no need to enhance selective pick up rather only prevent LH/CG transport to inappropriate sites. Abnormal placental LHR expression may play a role in the development of abnormal pregnancy. Expression of LHR in the pelvic floor compartments suggests that high LH levels in postmenopausal women may contribute to the pelvic floor relaxation and increased incidence of pelvic floor disorders. Since chorionic gonadotropin increases secretion of a variety of cytokines by monocytes, and induces their inflammatory reaction and phagocytic activity, high LH levels in aging individuals may also activate microglia (mononuclear phagocyte system in the central nervous system) and contribute to the development of Alzheimer's disease and other inflammation-mediated neurodegenerative diseases.

Placental expression of estrogen receptor beta and its hormone binding variant--comparison with estrogen receptor alpha and a role for estrogen receptors in asymmetric division and differentiation of estrogen-dependent cells

During human pregnancy, the production of 17-beta-estradiol (E2) rises steadily to eighty fold at term, and placenta has been found to specifically bind estrogens. We have recently demonstrated the expression of estrogen receptor alpha (ER-alpha) protein in human placenta and its localization in villous cytotrophoblast (CT), vascular pericytes, and amniotic fibroblasts. In vitro, E2 stimulated development of large syncytiotrophoblast (ST) aggregates. In the present study we utilized ER-beta affinity purified polyclonal (N19:sc6820) and ER-alpha monoclonal (clone h-151) antibodies. Western blot analysis revealed a single approximately 52 kDa ER-beta band in chorionic villi (CV) protein extracts. In CV, strong cytoplasmic ER-beta immunoreactivity was confined to ST. Dual color immunohistochemistry revealed asymmetric segregation of ER-alpha in dividing villous CT cells. Prior to separation, the cell nuclei more distant from ST exhibited high ER-alpha, while cell nuclei associated with ST showed diminution of ER-alpha and appearance of ER-beta. In trophoblast cultures, development of ST aggregates was associated with diminution of ER-alpha and appearance of ER-beta immunoreactivity. ER-beta was also detected in endothelial cells, amniotic epithelial cells and fibroblasts, extravillous trophoblast (nuclear and cytoplasmic) and decidual cells (cytoplasmic only). In addition, CFK-E12 (E12) and CWK-F12 (F12) monoclonal antibodies, which recognize approximately 64 kDa ER-beta with hormone binding domain, showed nuclear-specific reactivity with villous ST, extravillous trophoblast, and amniotic epithelium and fibroblasts. Western blot analysis indicated abundant expression of a approximately 64 kDa ER-beta variant in trophoblast cultures, significantly higher when compared to the chorionic villi and freshly isolated trophoblast cell protein extracts. This is the first report on ER-beta expression in human placenta and cultured trophoblast. Our data indicate that during trophoblast differentiation, the ER-alpha is associated with a less, and ER-beta with the more differentiated state. Enhanced expression of approximately 64 kDa ER-beta variant in trophoblast cultures suggests a unique role of ER-beta hormone binding domain in the regulation of trophoblast differentiation. Our data also indicate that asymmetric segregation of ER-alpha may play a role in asymmetric division of estrogen-dependent cells.

Expression and localization of estrogen receptor-alpha protein in normal and abnormal term placentae and stimulation of trophoblast differentiation by estradiol

Estrogens play an important role in the regulation of placental function, and 17-beta-estradiol (E2) production rises eighty fold during human pregnancy. Although term placenta has been found to specifically bind estrogens, cellular localization of estrogen receptor alpha (ER-alpha) in trophoblast remains unclear. We used western blot analysis and immunohistochemistry with h-151 and ID5 monoclonal antibodies to determine the expression and cellular localization of ER-alpha protein in human placentae and cultured trophoblast cells. Western blot analysis revealed a ~65 kDa ER-alpha band in MCF-7 breast carcinoma cells (positive control). A similar band was detected in five normal term placentae exhibiting strong expression of Thy-1 differentiation protein in the villous core. However, five other term placentae, which exhibited low or no Thy-1 expression (abnormal placentae), exhibited virtually no ER-alpha expression. In normal placentae, nuclear ER-alpha expression was confined to villous cytotrophoblast cells (CT), but syncytiotrophoblast (ST) and extravillous trophoblast cells were unstained. In abnormal placentae no CT expressing ER-alpha were detected. Normal and abnormal placentae also showed ER-alpha expression in villous vascular pericytes and amniotic (but not villous) fibroblasts; no staining was detected in amniotic epithelial cells or decidual cells. All cultured trophoblast cells derived from the same normal and abnormal placentae showed distinct ER-alpha expression in western blots, and the ER-alpha expression was confined to the differentiating CT, but not to the mature ST. Trophoblast cells from six additional placentae were cultured in normal medium with phenol red (a weak estrogen) as above (PhR+), or plated in phenol red-free medium (PhR-) without or with mid-pregnancy levels of E2 (20 nM). Culture in PhR- medium without E2 caused retardation of syncytium formation and PhR-medium with E2 caused acceleration of syncytium formation compared to cultures in PhR+ medium. These data indicate that the considerable increase in estrogen production during pregnancy may play a role, via the ER-alpha, in the stimulation of CT differentiation and promote function in normal placentae. This mechanism, however, may not operate in abnormal placentae, which show a lack of ER-alpha expression.