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1.  Roles for Endothelin Receptor B and BCL2A1 in Spontaneous CNS Metastasis of Melanoma 
Cancer research  2012;72(19):4909-4919.
Metastatic spread of melanoma to the central nervous system (CNS) is a common and devastating manifestation of disease progression, which, despite its clinical importance, remains poorly understood with respect to underlying molecular mechanisms. Using a recently developed preclinical model of spontaneous melanoma CNS metastasis, we have identified alterations in expression of endothelin receptor B (EDNRB) as a potential factor that influences brain metastatic potential. Induced overexpression of this gene mediated enhanced overall metastatic disease, and resulted in an increased incidence of spontaneous CNS metastases. In contrast, the overexpression of other highlighted genes, such as BCL2A1, did not affect the incidence of CNS metastases but nevertheless appears to facilitate intracranial tumor growth. The prometastatic effect in the CNS associated with EDNRB appears to be mediated by the interaction with its ligands resulting in enhanced tumor cell proliferation and thus intracranial melanoma growth. That EDNRB contributes to melanoma metastasis is underscored by the fact that its therapeutic inhibition by the EDNRB-specific inhibitor A192621 translated into improved outcomes when treating mice with either visceral metastases or intracranial tumors. The identification of an influential role of EDNRB in CNS melanoma spontaneous metastasis may provide both a target for therapeutic intervention as well as a potential prognostic marker for patients having an increased predisposition for incidence of CNS melanoma metastases.
PMCID: PMC4334445  PMID: 22865454
Cancer research  2013;73(9):2743-2748.
The failure rate of randomized phase III oncology clinical trials is extremely high, even when preceded by encouraging preclinical studies and phase II trial results of the same therapy. Thus there is considerable effort being made to improve the predictive clinical potential of preclinical models, in addition to improving phase II trial design. With respect to the former, preclinical models have historically relied heavily on treatment of primary spontaneous or transplanted tumors rather than the more common and therapeutically challenging clinical trial circumstance of advanced metastatic disease. Here we show that the oral antiangiogenic tyrosine kinase inhibitor (TKI), sunitinib, which failed to meet primary or secondary survival endpoints in four separate phase III metastatic breast cancer (MBC) trials, either alone or with chemotherapy, similarly failed to show monotherapy or combination chemotherapy efficacy in a model of postsurgical advanced MBC, using a metastatic variant of the MDA-MB-231 triple negative human breast cancer. In contrast, the drug was effective when used to treat established orthotopic primary tumors. Similar results were obtained with pazopanib monotherapy, another antiangiogenic oral TKI. However, when an antibody targeting the VEGF pathway (DC101) was tested, it showed a trend in modestly improving the efficacy of paclitaxel therapy, thus resembling to a degree prior phase III clinical results of bevacizumab plus paclitaxel in MBC. Our results suggest the potential value of treating postsurgical advanced metastatic disease as a possible strategy to improve preclinical models for predicting outcomes in patients with metastatic disease.
PMCID: PMC4334448  PMID: 23610448
3.  Galectin-1 drives pancreatic carcinogenesis through stroma remodeling and Hedgehog signaling activation 
Cancer research  2014;74(13):3512-3524.
Pancreatic ductal adenocarcinoma (PDA) is the most aggressive tumor, showing incidence and mortality values almost identical. Despite remarkable advances in PDA molecular characterization, this disease is still refractory to current treatments. Desmoplastic stroma, a constant hallmark of PDA, has recently emerged as the major responsible for PDA therapeutic resistance, therefore representing a promising target. Galectin-1 (Gal1), a glycan-binding protein, is highly expressed in PDA stroma but its role remains unknown. Here, we aim to understand in vivo Gal1 functions and the molecular pathways responsible for its oncogenic properties. Genetic ablation of Gal1 in Ela-myc mice dampens tumor progression through inhibition of proliferation, angiogenesis, desmoplasia and stimulation of tumor-associated immune response, resulting in a 20% increase on the animal life span. In vitro and in vivo studies unveil that these effects are mediated by modulation of the tumor microenvironment in a non-cell autonomous manner. Importantly, acinar-to-ductal metaplasia, a crucial step for PDA initiation, is also regulated by Gal1. Finally, high-throughput gene expression studies and molecular analysis aimed at identifying the underlying mechanism revealed that Gal1 promotes Hedgehog pathway both in PDA cells and stromal fibroblasts. In summary, our studies define a novel role of Gal1 in PDA tumor epithelium-stroma crosstalk and suggest this lectin as potential molecular target for therapy of neoplasms overexpressing Gal1.
PMCID: PMC4332591  PMID: 24812270
Galectin-1; Hedgehog; pancreatic cancer; tumor microenvironment; acinar-to-ductal metaplasia
4.  Targeted deletion of Rad9 in mouse skin keratinocytes enhances genotoxin-induced tumor development 
Cancer research  2008;68(14):5552-5561.
The Rad9 gene is evolutionarily conserved from yeast to human, and plays crucial roles in genomic maintenance, DNA repair and cell cycle checkpoint controls. However, the function of this gene with respect to tumorigenesis is not well understood. A Rad9-null mutation in mice causes embryonic lethality. In this study, we created mice in which mouse Rad9, Mrad9, was deleted only in keratinocytes to permit examination of the potential function of the gene in tumor development. Mice with Mrad9+/− or Mrad9−/− keratinocytes demonstrated no overt, spontaneous morphological defects and appeared similar to wild-type controls. Painting the carcinogen 7,12-dimethylbenzanthracene (DMBA) onto the skin of the animals caused earlier onset and more frequent formation of tumors and senile skin plaques in Mrad9−/− mice, compared to Mrad9+/− and Mrad9+/+ littermates. DNA damage response genes p21, p53 and Mrad9B were expressed at higher levels in Mrad9−/− relative to Mrad9+/+ skin. Keratinocytes isolated from Mrad9−/− skin had more spontaneous and DMBA-induced DNA double strand breaks than Mrad9+/+ keratinocytes, and the levels were reduced by incubation with the antioxidant EGCG. These data suggest that Mrad9 plays an important role in maintaining genomic stability and preventing tumor development in keratinocytes.
PMCID: PMC4331354  PMID: 18632607
Rad9; conditional gene knockout; genomic stability; skin tumorigenesis; skin ageing
5.  Tumor Irradiation Increases the Recruitment of Circulating Mesenchymal Stem Cells into the Tumor Microenvironment 
Cancer research  2007;67(24):11687-11695.
Mesenchymal stem cells (MSC) migrate to and proliferate within sites of inflammation and tumors as part of the tissue remodeling process. Radiation increases the expression of inflammatory mediators that could enhance the recruitment of MSC into the tumor microenvironment. To investigate this, bilateral murine 4T1 breast carcinomas (expressing renilla luciferase) were irradiated unilaterally (1 or 2 Gy). Twenty-four hours later, 2 × 105 MSC-expressing firefly luciferase were injected i.v. Mice were then monitored with bioluminescent imaging for expression of both renilla (tumor) and firefly (MSC) luciferase. Forty-eight hours postirradiation, levels of MSC engraftment were 34% higher in tumors receiving 2 Gy (P = 0.004) than in the contralateral unirradiated limb. Immunohistochemical staining of tumor sections from mice treated unilaterally with 2 Gy revealed higher levels of MSC in the parenchyma of radiated tumors, whereas a higher proportion of MSC remained vasculature-associated in unirradiated tumors. To discern the potential mediators involved in MSC attraction, in vitro migration assays showed a 50% to 80% increase in MSC migration towards conditioned media from 1 to 5 Gy-irradiated 4T1 cells compared with unirradiated 4T1 cells. Irradiated 4T1 cells had increased expression of the cytokines, transforming growth factor-β1, vascular endothelial growth factor, and platelet-derived growth factor-BB, and this up-regulation was confirmed by immunohistochemistry in tumors irradiated in vivo. Interestingly, the chemokine receptor CCR2 was found to be up-regulated in MSC exposed to irradiated tumor cells and inhibition of CCR2 led to a marked decrease of MSC migration in vitro. In conclusion, clinically relevant low doses of irradiation increase the tropism for and engraftment of MSC in the tumor microenvironment.
PMCID: PMC4329784  PMID: 18089798
6.  Light In and Sound Out: Emerging Translational Strategies for Photoacoustic Imaging 
Cancer research  2014;74(4):979-1004.
Photoacoustic imaging has the potential for real-time molecular imaging at high resolution and deep inside the tissue, using non-ionizing radiation and not necessarily depending on exogenous imaging agents, making this technique very promising for a range of clinical applications. The fact that photoacoustic imaging systems can be made portable and compatible with existing imaging technologies favors clinical translation even more. The breadth of clinical applications in which photoacoustics could play a valuable role include: noninvasive imaging of the breast, sentinel lymph nodes, skin, thyroid, eye, prostate (transrectal), and ovaries (transvaginal); minimally invasive endoscopic imaging of gastrointestinal tract, bladder, and circulating tumor cells (in vivo flow cytometry); and intraoperative imaging for assessment of tumor margins and (lymph node) metastases. In this review we describe the basics of photoacoustic imaging and its recent advances in biomedical research, followed by a discussion of strategies for clinical translation of the technique.
PMCID: PMC3944207  PMID: 24514041
Photoacoustic Imaging; Molecular Imaging; Optoacoustic imaging; Clinical Translation; Translational Biomedical Research
7.  Collagen signaling enhances tumor progression after anti-VEGF therapy in a murine model of pancreatic ductal adenocarcinoma 
Cancer research  2013;74(4):1032-1044.
There is growing evidence that anti-angiogenic therapy stimulates cancer cell invasion and metastasis. However, the underlying molecular mechanisms responsible for these changes have not been fully defined. Here we report that anti-VEGF therapy promotes local invasion and metastasis by inducing collagen signaling in cancer cells. We show that chronic VEGF inhibition in a genetically engineered mouse model (GEMM) of pancreatic ductal adenocarcinoma (PDA) induces hypoxia, a less differentiated mesenchymal-like tumor cell phenotype, TGFβ expression, and collagen deposition and signaling. Additionally, we show that collagen signaling is critical for pro-tumorigenic activity of TGFβ in vitro. To further model the impact of collagen signaling in tumors, we evaluated PDA in mice lacking Sparc, a protein that reduces collagen binding to cell surface receptors. Importantly, we show that loss of Sparc increases collagen signaling and tumor progression. Together, these findings suggest that collagen actively promotes PDA spread and that enhanced disease progression associated with anti-VEGF therapy can arise from elevated ECM-mediated signaling.
PMCID: PMC3944405  PMID: 24346431
pancreatic cancer; VEGF; Sparc; collagen; Peak1; epithelial to mesenchymal transition
8.  The niacin/butyrate receptor GPR109A suppresses mammary tumorigenesis by inhibiting cell survival 
Cancer research  2013;74(4):1166-1178.
GPR109A, a G-protein-coupled receptor, is activated by niacin and butyrate. Upon activation in colonocytes, GPR109A potentiates anti-inflammatory pathways, induces apoptosis, and protects against inflammation-induced colon cancer. In contrast, GPR109A activation in keratinocytes induces flushing by activation of Cox-2-dependent inflammatory signaling and, the receptor expression is upregulated in human epidermoid carcinoma. Thus, depending on the cellular context and tissue, GPR109A functions either as a tumor suppressor or a tumor promoter. However, the expression status and the functional implications of this receptor in the mammary epithelium are not known. Here we show that GPR109A is expressed in normal mammary tissue and, irrespective of the hormone receptor status, its expression is silenced in human primary breast tumor tissues, breast cancer cell lines, and in tumor tissues of three different murine mammary tumor models. Functional expression of this receptor in human breast cancer cell lines decreases cAMP production, induces apoptosis, and blocks colony formation and mammary tumor growth. Transcriptome analysis revealed that GPR109A activation inhibits genes, which are involved in cell survival and anti-apoptotic signaling, in human breast cancer cells. In addition, deletion of Gpr109a in mice increased tumor incidence and triggered early onset of mammary tumorigenesis with increased lung metastasis in MMTV-Neu mouse model of spontaneous breast cancer. These findings suggest that GPR109A is a tumor suppressor in mammary gland and that pharmacological induction of this gene in tumor tissues followed by its activation with agonists could be an effective therapeutic strategy to treat breast cancer.
PMCID: PMC3944627  PMID: 24371223
9.  Activation of the NOTCH pathway in Head and Neck Cancer 
Cancer research  2013;74(4):1091-1104.
NOTCH1 mutations have been reported to occur in 10 to 15% of head and neck squamous cell carcinomas (HNSCC). To determine the significance of these mutations, we embarked upon a comprehensive study of NOTCH signaling in a cohort of 44 HNSCC tumors and 25 normal mucosal samples through a set of expression, copy number, methylation and mutation analyses. Copy number increases were identified in NOTCH pathway genes including the NOTCH ligand JAG1. Gene set analysis defined a differential expression of the NOTCH signaling pathway in HNSCC relative to normal tissues. Analysis of individual pathway-related genes revealed overexpression of ligands JAG1 and JAG2 and receptor NOTCH3. In 32% of the HNSCC examined, activation of the downstream NOTCH effectors HES1/HEY1 was documented. Notably, exomic sequencing identified 5 novel inactivating NOTCH1 mutations in 4/37 of the tumors analyzed, with none of these tumors exhibiting HES1/HEY1 overexpression. Our results revealed a bimodal pattern of NOTCH pathway alterations in HNSCC, with a smaller subset exhibiting inactivating NOTCH1 receptors mutations but a larger subset exhibiting other NOTCH1 pathway alterations, including increases in expression or gene copy number of the receptor or ligands as well as downstream pathway activation. Our results imply that therapies that target the NOTCH pathway may be more widely suitable for HNSCC treatment than appreciated currently.
PMCID: PMC3944644  PMID: 24351288
10.  GPR56 Inhibits Melanoma Growth by Internalizing and Degrading Its Ligand TG2 
Cancer research  2013;74(4):1022-1031.
Excessive accumulation of extracellular matrix (ECM) is a hallmark of tumor microenvironment and plays active roles during tumor progression. How this process is regulated and whether it is reversible for cancer treatment are outstanding questions. The adhesion G protein-coupled receptor GPR56 inhibits melanoma growth and binds to tissue transglutaminase (TG2), a major cross-linking enzyme in ECM. To understand the function of TG2 in GPR56-mediated melanoma inhibition, we performed xenograft studies in immunodeficient Tg2−/− mice. Our results revealed an antagonistic relationship between GPR56 and TG2 in melanoma: while TG2 and its crosslinking activity promote melanoma growth, GPR56 antagonizes this effect by internalizing and degrading it. The negative regulation of TG2 by GPR56 associates with the decreased deposition of a major ECM protein, fibronectin, and impaired accumulation of focal adhesion kinase, indicating that the GPR56-TG2 interaction regulates ECM deposition and cell-ECM adhesion. Taken together, our findings establish the roles of TG2 in GPR56-mediated melanoma inhibition. The uncovered antagonistic relationship between GPR56 and TG2 proposes a mechanism by which ECM accumulation/crosslinking in tumors may be reversed, and thus could have therapeutic potential for cancer control and treatment.
PMCID: PMC3944670  PMID: 24356421
11.  Tumor Suppressor Alterations Cooperate to Drive Aggressive Mesotheliomas with Enriched Cancer Stem Cells via a p53-miR34a-c-Met Axis 
Cancer research  2013;74(4):1261-1271.
Malignant mesothelioma (MM) is a highly aggressive, asbestos-related cancer frequently marked by mutations of both NF2 and CDKN2A. We demonstrate that germline knockout of one allele of each of these genes causes accelerated onset and progression of asbestos-induced MM compared to asbestos-exposed Nf2+/− or wild-type (WT) mice. Ascites from some Nf2+/−;Cdkn2a+/− mice exhibited large tumor spheroids, and tail vein injections of MM cells established from these mice, but not from Nf2+/− or WT mice, produced numerous tumors in the lung, suggesting increased metastatic potential of tumor cells from Nf2+/−;Cdkn2a+/− mice. Intraperitoneal injections of MM cells derived from Nf2+/−;Cdkn2a+/− mice into SCID mice produced tumors that penetrated the diaphragm and pleural cavity and harbored an increased cancer stem cells (CSCs). MM cells from Nf2+/−;Cdkn2a+/− mice stained positively for CSC markers and formed CSC spheroids in vitro more efficiently than counterparts from WT mice. Moreover, tumor cells from Nf2+/−;Cdkn2a+/− mice showed elevated c-Met expression/activation, which was partly dependent on p53-mediated regulation of miR34a and required for tumor migration/invasiveness and maintenance of the CSC population. Collectively, these studies demonstrate in vivo that inactivation of Nf2 and Cdkn2a cooperate to drive the development of highly aggressive MMs characterized by enhanced tumor spreading capability and the presence of a CSC population associated with p53/miR34a-dependent activation of c-Met. These findings suggest that cooperativity between losses of Nf2 and Cdkn2a plays a fundamental role in driving the highly aggressive tumorigenic phenotype considered to be a hallmark of MM.
PMCID: PMC3945416  PMID: 24371224
malignant mesothelioma; tumor suppressor genes; cancer stem cells; metastasis; mouse models
12.  PD-1 and Tim-3 regulate the expansion of tumor antigen-specific CD8+ T cells induced by melanoma vaccines 
Cancer research  2013;74(4):1045-1055.
Although melanoma vaccines stimulate tumor antigen (TA)-specific CD8+ T cells, objective clinical responses are rarely observed. To investigate this discrepancy, we evaluated the character of vaccine-induced CD8+ T cells with regard to the inhibitory T cell co-receptors PD-1 and Tim-3 in metastatic melanoma patients who were administered tumor vaccines. The vaccines included incomplete Freund's adjuvant (IFA), CpG oligodeoxynucleotide (CpG) and the HLA-A2-restricted analog peptide NY-ESO-1 157-165V, either by itself or in combination with the pan-DR epitope NY-ESO-1 119-143. Both vaccines stimulated rapid TA-specific CD8+ T-cell responses detected ex vivo, however, TA-specific CD8+ T cells produced more IFN-γ and exhibited higher lytic function upon immunization with MHC class I and class II epitopes. Notably, the vast majority of vaccine-induced CD8+ T cells upregulated PD-1 and a minority also upregulated Tim-3. Levels of PD-1 and Tim-3 expression by vaccine-induced CD8+ T cells at the time of vaccine administration correlated inversely with their expansion in vivo. Dual blockade of PD-1 and Tim-3 enhanced the expansion and cytokine production of vaccine-induced CD8+ T cells in vitro. Collectively, our findings support the use of PD-1 and Tim-3 blockades with cancer vaccines to stimulate potent antitumor T cell responses and increase the likelihood of clinical responses in advanced melanoma patients.
PMCID: PMC3952491  PMID: 24343228
Peptide-based vaccine; PD-1; Tim-3; CD8+ T cells; Melanoma
13.  Inducible nitric oxide synthase (iNOS) drives mTOR pathway activation and proliferation of human melanoma by reversible nitrosylation of TSC2 
Cancer research  2014;74(4):1067-1078.
Melanoma is one of the cancers of fastest-rising incidence in the world. iNOS is overexpressed in melanoma and other cancers, and previous data suggest that iNOS and nitric oxide (NO) drive survival and proliferation of human melanoma cells. However, specific mechanisms through which this occurs are poorly defined. One candidate is the PI3K/AKT/mTOR pathway, which plays a major role in proliferation, angiogenesis, and metastasis of melanoma and other cancers. We used the chick embryo chorioallantoic membrane (CAM) assay to test the hypothesis that melanoma growth is regulated by iNOS-dependent mTOR pathway activation. Both pharmacologic inhibition and siRNA-mediated gene silencing of iNOS suppressed melanoma proliferation and in vivo growth on the CAM in human melanoma models. This was associated with strong downregulation of mTOR pathway activation by Western blot analysis of p-mTOR, p-P70S6K, p-S6RP, and p-4EBP1. iNOS expression and NO were associated with reversible nitrosylation of TSC2, and inhibited dimerization of TSC2 with its inhibitory partner TSC1, enhancing GTPase activity of its target Rheb, a critical activator of mTOR signaling. Immunohistochemical analysis of tumor specimens from stage III melanoma patients showed a significant correlation between iNOS expression levels and expression of mTOR pathway members. Exogenously-supplied NO was also sufficient to reverse mTOR pathway inhibition by the B-Raf inhibitor Vemurafenib. In summary, covalent modification of TSC2 by iNOS-derived NO is associated with impaired TSC2/TSC1 dimerization, mTOR pathway activation, and proliferation of human melanoma. This model is consistent with the known association of iNOS overexpression and poor prognosis in melanoma and other cancers.
PMCID: PMC3960077  PMID: 24398473
nitric oxide; mTOR; melanoma; nitrosylation; inducible nitric oxide synthase
14.  A preclinical model of CD38-pretargeted radioimmunotherapy for plasma cell malignancies 
Cancer research  2013;74(4):1179-1189.
The vast majority of patients with plasma cell neoplasms die of progressive disease despite high response rates to novel agents. Malignant plasma cells are very radiosensitive, but the potential role of radioimmunotherapy (RIT) in the management of plasmacytomas and multiple myeloma (MM) has undergone only limited evaluation. Furthermore, CD38 has not been explored as a RIT target despite its uniform high expression on plasma cell malignancies. In this report, both conventional RIT (directly radiolabeled antibody) and streptavidin-biotin pretargeted RIT (PRIT) directed against the CD38 antigen, were assessed as approaches to deliver radiation doses sufficient for MM cell eradication. PRIT demonstrated biodistributions that were markedly superior to conventional RIT. Tumor-to-blood ratios as high as 638:1 were seen 24hr after PRIT, while ratios never exceeded 1:1 with conventional RIT. 90Yttrium absorbed dose estimates demonstrated excellent target-to-normal organ ratios (6:1 for the kidney, lung, liver; 10:1 for the whole body). Objective remissions were observed within 7 days in 100% of the mice treated with doses ranging from 800 µCi to 1200 µCi of anti-CD38 pretargeted 90Y-DOTA-biotin, including 100% complete remissions (no detectable tumor in treated mice compared to tumors that were 2982±2834% of initial tumor volume in control animals) by day 23. Furthermore, 100% of animals bearing NCI-H929 multiple myeloma tumor xenografts treated with 800 µCi of anti-CD38 pretargeted 90Y-DOTA-biotin achieved long-term myeloma-free survival (>70 days) compared to none (0%) of the control animals.
PMCID: PMC3970848  PMID: 24371230
Radioimmunotherapy; multiple myeloma; CD38; pretargeting; preclinical
15.  Curcumin targets breast cancer stem-like cells with microtentacles that persist in mammospheres and promote reattachment 
Cancer research  2013;74(4):1250-1260.
Cancer stem-like cells (CSC) and circulating tumor cells (CTCs) have related properties associated with distant metastasis, but the mechanisms through which CSCs promote metastasis are unclear. In this study, we report that breast cancer cell lines with more stem-like properties display higher levels of microtentacles (McTNs), a type of tubulin-based protrusion of the plasma cell membrane which forms on detached or suspended cells and aid in cell reattachment. We hypothesized that CSCs with large numbers of McTNs would more efficiently attach to distant tissues, promoting metastatic efficiency. The naturally occurring stem-like subpopulation of the HMLE breast cell line presents increased McTNs compared to its isogenic non-stem-like subpopulation. This increase was supported by elevated α-tubulin detyrosination and vimentin protein levels and organization. Increased McTNs in stem-like HMLEs promoted a faster initial reattachment of suspended cells that was inhibited by the tubulin-directed drug, colchicine, confirming a functional role for McTN in stem cell reattachment. Moreover, live cell confocal microscopy showed that McTN persist in breast stem cell mammospheres as flexible, motile protrusions on the surface of the mammosphere. While exposed to the environment, they also function as extensions between adjacent cells along cell-cell junctions. We found that treatment with the breast CSC-targeting compound curcumin rapidly extinguished McTN in breast CSC, preventing reattachment from suspension. Together, our results support a model in which breast CSCs with cytoskeletal alterations that promote McTN can mediate attachment and metastasis but might be targeted by curcumin as an anti-metastatic strategy.
PMCID: PMC3990412  PMID: 24371229
Microtentacles; Circulating Tumor Cells; Breast Cancer Stem Cells; Reattachment; Curcumin; Tubulin
16.  In vivo regulation of human glutathione transferase GSTP by chemopreventive agents 
Cancer research  2014;74(16):4378-4387.
Relatively little progress has been made in determining the in vivo regulation of glutathione S-transferase P (GSTP), particularly the human enzyme hGSTP1, despite being identified as a significant factor in carcinogenesis and development of drug resistance in tumor cell lines. Here we report the characterization of a transgenic reporter mouse that reveals how hGSTP1 is regulated in vivo by chemopreventive agents. Basal expression was found in crypts and villi of the small and large intestine, bronchiolar epithelial cells, the epidermis and hair follicles, gall bladder epithelium, choroid plexus and biliary epithelium. Expression was induced in different tissues by the antioxidant chemopreventive agents ethoxyquin (EQ) and butylated hydroxyanisole (BHA). However, genetic deletion of the Nrf2 transcription factor, which directs central genetic programs of detoxification and protection against oxidative stress, increased rather than attenuated GSTP1 expression. In vitro investigations with mouse embryonic fibroblasts revealed factor(s) in addition to Nrf2 that control the expression of GSTP1, offering further insights into regulation. The new reporter mouse described here provides a useful tool to gain deeper insights into the mechanisms of action of chemopreventive compounds and other environmental agents.
PMCID: PMC4134684  PMID: 24934809
human GSTP1; regulation; reporter
17.  The Decline in US Cancer Mortality in People Born Since 1925 
Cancer research  2009;69(16):6500-6505.
The conventional practice of analyzing overall age-adjusted cancer mortality rates heavily emphasizes the experience of older, higher mortality age groups. This may conceal shifts in lifetime cancer mortality experience emerging first in younger age groups.
We examined age-specific cancer mortality rates and birth-cohort-specific cancer mortality rates in US mortality data recorded since 1955 to assess the effects of age, period and cohort in secular mortality trends. Cancer mortality and population data were obtained from the World Health Organization's Statistical Information System (WHOSIS).
Age-specific cancer mortality rates have been steadily declining in the U.S. since the early 1950's, beginning with children and young adults and now including all age groups. During the second half of the 20th century, each successive decade of births from 1925 - 1995 experienced a lower risk of cancer death than its predecessor at virtually every age for which such a comparison can be made.
A major decline in cancer mortality has been occurring in the U.S. for the past fifty years, affecting birth cohorts born as long as eighty years ago. Excepting lung cancer, much of this decline has occurred despite relatively stable cancer incidence. These findings suggest that improvements in cancer detection, treatment, and/or prevention have reduced the risk of cancer death across the lifespan for individuals born in the last three-quarters of the 20th century.
PMCID: PMC4326089  PMID: 19679548
Cohort analysis; Cancer mortality; Cancer surveillance and screening; Methodology, modeling, and biostatistics
18.  Adenomatous polyps are driven by microbe-instigated focal inflammation and are controlled by IL-10 producing T-cells 
Cancer research  2013;73(19):5905-5913.
Interleukin-10 (IL-10) is elevated in cancer and is thought to contribute to immune tolerance and tumor growth. Defying these expectations, the adoptive transfer of IL-10 expressing T-cells to mice with polyposis attenuates microbial-induced inflammation and suppresses polyposis. To gain better insights into how IL-10 impacts polyposis, we genetically ablated IL-10 in T-cells in APCΔ468 mice and compared the effects of treatment with broad-spectrum antibiotics. We found that T-cells and Tregs were a major cellular source of IL-10 in both the healthy and polyp-bearing colon. Notably, T-cell-specific ablation of IL-10 produced pathologies that were identical to mice with a systemic deficiency in IL-10, in both cases increasing the numbers and growth of colon polyps. Eosinophils were found to densely infiltrate colon polyps, which were enriched similarly for microbiota associated previously with colon cancer. In mice receiving broad-spectrum antibiotics, we observed reductions in microbiota, inflammation, and polyposis. Together our findings establish that colon polyposis is driven by high densities of microbes that accumulate within polyps and trigger local inflammatory responses. Inflammation, local microbe densities, and polyp growth are suppressed by IL-10 derived specifically from T-cells and Tregs.
PMCID: PMC4322779  PMID: 23955389
interleukin-10; polyposis; microbiota; inflammation; colon
19.  BCL9 Promotes Tumor Progression by Conferring Enhanced Proliferative, Metastatic, and Angiogenic Properties to Cancer Cells 
Cancer research  2009;69(19):7577-7586.
Several components of the Wnt signaling cascade have been shown to function either as tumor suppressor proteins or as oncogenes in multiple human cancers, underscoring the relevance of this pathway in oncogenesis and the need for further investigation of Wnt signaling components as potential targets for cancer therapy. Here, using expression profiling analysis as well as in vitro and in vivo functional studies, we show that the Wnt pathway component BCL9 is a novel oncogene that is aberrantly expressed in human multiple myeloma as well as colon carcinoma. We show that BCL9 enhances β-catenin–mediated transcriptional activity regardless of the mutational status of the Wnt signaling components and increases cell proliferation, migration, invasion, and the metastatic potential of tumor cells by promoting loss of epithelial and gain of mesenchymal-like phenotype. Most importantly, BCL9 knockdown significantly increased the survival of xenograft mouse models of cancer by reducing tumor load, metastasis, and host angiogenesis through down-regulation of c-Myc, cyclin D1, CD44, and vascular endothelial growth factor expression by tumor cells. Together, these findings suggest that deregulation of BCL9 is an important contributing factor to tumor progression. The pleiotropic roles of BCL9 reported in this study underscore its value as a drug target for therapeutic intervention in several malignancies associated with aberrant Wnt signaling.
PMCID: PMC4321734  PMID: 19738061
20.  High-resolution Global Genomic Survey of 178 Gliomas Reveals Novel Regions of Copy Number Alteration and Allelic Imbalances 
Cancer research  2006;66(19):9428-9436.
Primary brain tumors are the fourth leading cause of cancer mortality in adults under the age of 54 years and the leading cause of cancer mortality in children in the United States. Therapy for the most common type of primary brain tumors, gliomas, remains suboptimal. The development of new and more effective treatments will likely require a better understanding of the biology of these tumors. Here, we show that use of the high-density 100K single-nucleotide polymorphism arrays in a large number of primary tumor samples allows for a much higher resolution survey of the glioma genome than has been previously reported in any tumor type. We not only confirmed alterations in genomic areas previously reported to be affected in gliomas, but we also refined the location of those sites and uncovered multiple, previously unknown regions that are affected by copy number alterations (amplifications, homozygous and heterozygous deletions) as well as allelic imbalances (loss of heterozygosity/gene conversions). The wealth of genomic data produced may allow for the development of a more rational molecular classification of gliomas and serve as an important starting point in the search for new molecular therapeutic targets.
PMCID: PMC4316202  PMID: 17018597
21.  Adiponectin Receptor Signaling on Dendritic Cells Blunts Antitumor Immunity 
Cancer research  2014;74(20):5711-5722.
Immune escape is a fundamental trait of cancer. Dendritic cells (DC) that interact with T cells represent a crucial site for the development of tolerance to tumor antigens, but there remains incomplete knowledge about how DC-tolerizing signals evolve during tumorigenesis. In this study, we show that DCs isolated from patients with metastatic or locally advanced breast cancer express high levels of the adiponectin receptors AdipoR1 and AdipoR2, which are sufficient to blunt antitumor immunity. Mechanistic investigations of ligand–receptor interactions on DCs revealed novel signaling pathways for each receptor. AdipoR1 stimulated IL10 production by activating the AMPK and MAPKp38 pathways, whereas AdipoR2 modified inflammatory processes by activating the COX-2 and PPARγ pathways. Stimulation of these pathways was sufficient to block activation of NF-κB in DC, thereby attenuating their ability to stimulate antigen-specific T-cell responses. Together, our findings reveal novel insights into how DC-tolerizing signals evolve in cancer to promote immune escape. Furthermore, by defining a critical role for adiponectin signaling in this process, our work suggests new and broadly applicable strategies for immunometabolic therapy in patients with cancer.
PMCID: PMC4314963  PMID: 25261236
22.  [No title available] 
PMCID: PMC3916780  PMID: 24492704
23.  [No title available] 
PMCID: PMC3928601  PMID: 24310399
24.  [No title available] 
PMCID: PMC3932503  PMID: 24322982
25.  [No title available] 
PMCID: PMC3933065  PMID: 24335958

Results 1-25 (3280)