bluuebunny/crossref_metadata_2025 huggingface dataset:
Fragile Histidine Triad–Mediated Tumor Suppression of Lung Cancer by Targeting Multiple Components of the Ras/Rho GTPase Molecular Switch
Authors: Jayachandran Gitanjali , Sazaki Ji-ichiro , Nishizaki Masahito , Xu Kai , Girard Luc , Minna John D. , Roth Jack A. , Ji Lin
Published: November 2007

The fragile histidine triad (FHIT) gene has been shown to function as a tumor suppressor gene in vitro and in vivo. However, the mechanism of its action is still largely unknown. To elucidate the molecular mechanism and biological pathway in FHIT-mediated tumor suppression, we used a complementary gene and protein expression profiling with DNA microarray and ProteinChip technologies to quantitatively monitor cellular changes in gene and protein expression and discover the molecular targets of FHIT in non–small cell lung carcinoma (NSCLC) cells. The Ras/Rho signaling pathway was identified as one of the unique biological pathways associated with FHIT activity. A significantly down-regulated expression of genes and proteins of multiple key components in the Ras/Rho GTPases molecular switch, including Ran, Rab, Rac, Rap, and Ral, was observed on gene and protein expression profiles and further validated by Western blot analysis. Ectopic activation of FHIT in FHIT-deficient H1299 cells also significantly reduced the invasive potential of tumor cells by down-regulating expression of RhoC, a potential marker of tumor cell invasion and metastases. A simultaneous knockdown of the expression of several key Ras/Rho signaling molecules using gene-specific small interfering RNAs (RHO-siRNA) targeting selected Rab11, Rac1, and Rap1 genes significantly inhibited tumor cell growth and induced apoptosis in NSCLC cells in vitro, and a local injection of RHO-siRNAs complexed with N-[1-(2,3-dioleoyloxyl)propyl]-N,N,N-trimethylammoniummethyl sulfate:cholesterol nanoparticles inhibited tumor growth in A549 tumor xenografts in mice, mimicking the AdFHIT-mediated tumor-suppressing effect. These results suggest a new role of FHIT in down-regulating the Ras/Rho GTPase-associated oncogenic signaling pathway. [Cancer Res 2007;67(21):10379–88]
Enhanced Activation of Human Dendritic Cells by Inducible CD40 and Toll-like Receptor-4 Ligation
Authors: Lapteva Natalia , Seethammagari Mamatha R. , Hanks Brent A. , Jiang Jianghong , Levitt Jonathan M. , Slawin Kevin M. , Spencer David M.
Published: November 2007

Despite the potency of dendritic cells (DC) as antigen-presenting cells for priming adaptive immunity, DC-based cancer vaccines have been largely insufficient to effectively reduce tumor burden or prevent tumor progression in most patients. To enhance DC-based vaccines, we used the combination of a synthetic ligand-inducible CD40 receptor (iCD40) along with Toll-like receptor-4 (TLR-4) ligation in human monocyte-derived DCs. The iCD40 receptor permits targeted, reversible activation of CD40 in vivo, potentially bypassing the essential role of CD4+ T cells for activation of DCs. As a rigorous preclinical study of this approach, we evaluated key parameters of DC activation and function. Whereas neither iCD40 nor TLR-4 signaling alone led to high levels of interleukin (IL)-12p70 and IL-6, using iCD40 in combination with lipopolysaccharide (LPS) or monophosphoryl lipid A led to strongly synergistic production of both. Furthermore, this approach led to high expression of DC maturation markers, epitope-specific CTL and T helper 1 responses, as well as DC migration in vitro and in vivo. Moreover, use of iCD40-modified and LPS-stimulated DCs led to targeted expansion of autologous T cells against tumor-associated antigens, including prostate-specific membrane antigen, and elimination of preestablished tumors, supporting this technology as a potent strategy for DC-based cancer immunotherapy. [Cancer Res 2007;67(21):10528–10]
Neuroendocrine Modulation of Signal Transducer and Activator of Transcription-3 in Ovarian Cancer
Authors: Landen Charles N. , Lin Yvonne G. , Armaiz Pena Guillermo N. , Das Pamela D. , Arevalo Jesusa M. , Kamat Aparna A. , Han Liz Y. , Jennings Nicholas B. , Spannuth Whitney A. , Thaker Premal H. , Lutgendorf Susan K. , Savary Cherylyn A. , Sanguino Angela M. , Lopez-Berestein Gabriel , Cole Steve W. , Sood Anil K.
Published: November 2007

There is growing evidence that chronic stress and other behavioral conditions are associated with cancer pathogenesis and progression, but the mechanisms involved in this association are poorly understood. We examined the effects of two mediators of stress, norepinephrine and epinephrine, on the activation of signal transducer and activator of transcription-3 (STAT3), a transcription factor that contributes to many promalignant pathways. Exposure of ovarian cancer cell lines to increasing concentrations of norepinephrine or epinephrine showed that both independently increased levels of phosphorylated STAT3 in a dose-dependent fashion. Immunolocalization and ELISA of nuclear extracts confirmed increased nuclear STAT3 in response to norepinephrine. Activation of STAT3 was inhibited by blockade of the β1- and β2-adrenergic receptors with propranolol, and by blocking protein kinase A with KT5720, but not with the α receptor blockers prazosin (α1) and/or yohimbine (α2). Catecholamine-mediated STAT3 activation was not inhibited by pretreatment with an anti–interleukin 6 (IL-6) antibody or with small interfering RNA (siRNA)–mediated decrease in IL-6 or gp130. Regarding the effects of STAT3 activation, exposure to norepinephrine resulted in an increase in invasion and matrix metalloproteinase (MMP-2 and MMP-9) production. These effects were completely blocked by STAT3-targeting siRNA. In mice, treatment with liposome-incorporated siRNA directed against STAT3 significantly reduced isoproterenol-stimulated tumor growth. These studies show IL-6–independent activation of STAT3 by norepinephrine and epinephrine, proceeding through the β1/β2-adrenergic receptors and protein kinase A, resulting in increased matrix metalloproteinase production, invasion, and in vivo tumor growth, which can be ameliorated by the down-regulation of STAT3. [Cancer Res 2007;67(21):10389–96]
Novel Indenoisoquinolines NSC 725776 and NSC 724998 Produce Persistent Topoisomerase I Cleavage Complexes and Overcome Multidrug Resistance
Authors: Antony Smitha , Agama Keli K. , Miao Ze-Hong , Takagi Kazutaka , Wright Mollie H. , Robles Ana I. , Varticovski Lyuba , Nagarajan Muthukaman , Morrell Andrew , Cushman Mark , Pommier Yves
Published: November 2007

Camptothecin (CPT) derivatives are effective anticancer drugs, especially against solid tumors. As CPTs are chemically unstable and have clinical limitations, we have synthesized indenoisoquinolines as novel topoisomerase I (Top1) inhibitors. We presently report two indenoisoquinoline derivatives, NSC 725776 and NSC 724998, which have been selected for therapeutic development. Both are potent Top1 inhibitors and induce Top1 cleavage at unique genomic positions compared with CPT. Consistent with Top1 poisoning, protein-linked DNA breaks were detected in cells treated with NSC 725776 and NSC 724998 at nanomolar concentrations. Those drug-induced protein-linked DNA breaks persisted longer after drug removal than those produced by CPT. Studies in human cells in culture show that NSC 725776 and NSC 724998 exert antiproliferative activity at submicromolar concentrations. Furthermore, NSC 725776 and NSC 724998 show cross-resistance in cells deficient or silenced for Top1, which is consistent with their selective Top1 targeting. Similar to other known Top1 inhibitors, NSC 725776–treated and NSC 724998–treated cells show an arrest of cell cycle progression in both S and G2-M and a dependence on functional p53 for their cytotoxicity. Dose-dependent γ-H2AX foci formation was readily observed in cells treated with NSC 725776 and NSC 724998. These γ-H2AX foci were detectable at pharmacologically relevant doses for up to 24 h and thus could be used as biomarkers for clinical trials (phase 0). [Cancer Res 2007;67(21):10397–405]
Senescence Mediates Pituitary Hypoplasia and Restrains Pituitary Tumor Growth
Authors: Chesnokova Vera , Zonis Svetlana , Rubinek Tami , Yu Run , Ben-Shlomo Anat , Kovacs Kalman , Wawrowsky Kolja , Melmed Shlomo
Published: November 2007

Understanding factors subserving pituitary cell proliferation enables understanding mechanisms underlying uniquely benign pituitary tumors. Pituitary tumor-transforming gene (Pttg) deletion results in pituitary hypoplasia, low pituitary cell proliferation rates, and rescue of pituitary tumor development in Rb+/− mice. Pttg−/− pituitary glands exhibit ARF/p53/p21-dependent senescence pathway activation evidenced by up-regulated p19, cyclin D1, and Bcl-2 protein levels and p53 stabilization. High pituitary p21 levels in the absence of PTTG were associated with suppressed cyclin-dependent kinase 2 activity, Rb phosphorylation, and cyclin A expression, all required for cell cycle progression. Although senescence-associated β-galactosidase was enhanced in Pttg-deficient pituitary glands, telomere lengths were increased. DNA damage signaling pathways were activated and aneuploidy was evident in the Pttg-deficient pituitary, triggering senescence-associated genes. To confirm the p21 dependency of decreased proliferation and senescence in the Pttg-null pituitary, mouse embryonic fibroblast (MEF) colony formation was tested in wild-type, Pttg−/−, Rb+/−, Rb+/−Pttg−/−, and Rb+/−Pttg−/−p21−/− cells. Rb+/−Pttg−/− MEFs, unlike Rb+/− cells, failed to produce colonies and exhibited high levels of senescence. p21 deletion from Rb+/−Pttg−/− MEFs enhanced anchorage-independent cell growth, accompanied by a marked decrease in senescence. As cell proliferation assessed by bromodeoxyuridine incorporation was higher in Rb+/−Pttg−/−p21−/− relative to Rb+/−Pttg−/− pituitary glands, p21-dependent senescence provoked by Pttg deletion may underlie pituitary hypoplasia and decreased tumor development in Rb+/−Pttg−/− mice. [Cancer Res 2007;67(21):10564–72]
Manganese Superoxide Dismutase Enhances the Invasive and Migratory Activity of Tumor Cells
Authors: Connor Kip M. , Hempel Nadine , Nelson Kristin K. , Dabiri Ganary , Gamarra Aldo , Belarmino James , Van De Water Livingston , Mian Badar M. , Melendez J. Andres
Published: November 2007

Clinically significant elevations in the expression of manganese superoxide dismutase (Sod2) are associated with an increased frequency of tumor invasion and metastasis in certain cancers. The aim of this study was to examine whether increases in Sod2 activity modulate the migratory potential of tumor cells, contributing to their enhanced metastatic behavior. Overexpression of Sod2 in HT-1080 fibrosarcoma cells significantly enhanced their migration 2-fold in a wound healing assay and their invasive potential 3-fold in a transwell invasion assay. Severity of invasion was directly correlated to Sod2 expression levels and this invasive phenotype was similarly observed in 253J bladder tumor cells, in which Sod expression resulted in a 3-fold increase in invasion compared with controls. Further, migration and invasion of the Sod2-expressing cells was inhibited following overexpression of catalase, indicating that the promigratory/invasive phenotype of Sod2-expressing cells is H2O2 dependent. Sod2 overexpression was associated with a loss of vinculin-positive focal adhesions that were recovered in cells coexpressing catalase. Tail vein injections of Sod2-GFP–expressing HT-1080 cells in NCR nude mice led to the development of pulmonary metastatic nodules displaying high Sod2-GFP expression. Isolated tumors were shown to retain high Sod2 activity in culture and elevated levels of the matrix degrading protein matrix metalloproteinase-1, and a promigratory phenotype was observed in a population of cells growing out from the tumor nodule. These findings suggest that the association between increased Sod2 activity and poor prognosis in cancer can be attributed to alterations in their migratory and invasive capacity. [Cancer Res 2007;67(21):10260–67]
Host Immunosurveillance Controls Tumor Growth via IFN Regulatory Factor-8–Dependent Mechanisms
Authors: Greeneltch Kristy M. , Schneider Monika , Steinberg Seth M. , Liewehr David J. , Stewart Trina J. , Liu Kebin , Abrams Scott I.
Published: November 2007

IFN regulatory factor (IRF)-8 plays an important role in normal myelopoiesis. The loss of IRF-8 in myeloid cells results in a chronic myelogenous leukemia–like syndrome, suggesting that IRF-8 behaves as a tumor suppressor gene in certain hematopoietic malignancies. We have been investigating the molecular determinants of solid tumor progression, with an emphasis on apoptotic resistance. Recently, we showed that IRF-8 expression was directly correlated with Fas-mediated apoptosis, and inversely related to malignant phenotype. However, the functional role of IRF-8 in solid tumors is unresolved. We stably silenced IRF-8 expression via RNA interference in IRF-8–expressing mouse tumor cells, and evaluated them for changes in apoptotic phenotype and malignant behavior. Apoptosis induced by Fas engagement or irradiation was markedly reduced in IRF-8–deficient tumor cells, despite unaltered proliferation, cell surface Fas, or MHC class I expression. Moreover, in syngeneic immunocompetent mice, IRF-8–deficient tumor cells grew more aggressively than their control counterparts. However, in IFN-γ– or Fas ligand–deficient mice, but not T cell–deficient mice, both control and IRF-8–deficient tumor populations grew similarly. Furthermore, both tumor populations grew similarly in mice with defects in innate immunity. Although subsequent studies precluded a role for natural killer cells, immunohistochemical analysis supported the involvement of macrophages. Overall, our findings show that IRF-8 expression in solid tumor cells is important for efficient host immunosurveillance and response to apoptotic stimuli. Therefore, IRF-8 down-regulation may represent a previously unrecognized tumor escape mechanism that facilitates tumor progression. Conversely, strategies aimed at up-regulating or restoring IRF-8 expression in neoplastic cells may improve therapeutic efficacy. [Cancer Res 2007;67(21):10406–16]
TSC2 Loss in Lymphangioleiomyomatosis Cells Correlated with Expression of CD44v6, a Molecular Determinant of Metastasis
Authors: Pacheco-Rodriguez Gustavo , Steagall Wendy K. , Crooks Denise M. , Stevens Linda A. , Hashimoto Hiroshi , Li Shaowei , Wang Ji-an , Darling Thomas N. , Moss Joel
Published: November 2007

Lymphangioleiomyomatosis (LAM), a rare multisystem disease found primarily in women of childbearing age, is characterized by the proliferation of abnormal smooth muscle–like cells, LAM cells, that form nodules in the pulmonary interstitium. Proliferation of LAM cells results, in part, from dysfunction in tuberous sclerosis complex (TSC) genes TSC1 (hamartin) and/or TSC2 (tuberin). Identification of LAM cells in donor lungs, their isolation from blood, and their presence in urine, chylous ascites, and pleural effusions are consistent with their ability to metastasize. Here, we investigated the presence on LAM cells of the hyaluronic acid receptor CD44 and its splice variants associated with metastasis. The heterogeneous populations of cells grown from lungs of 12 LAM patients contain cells expressing mRNA for the variant CD44v6. Histologically, CD44v6 was present in LAM lung nodules, but not in normal vascular smooth muscle cells. CD44v6-positive sorted cells showed loss of heterozygosity at the TSC2 locus; binding of CD44v6 antibody resulted in loss of cell viability. Levels of CD44 were higher in cultured Eker rat (Tsc2−/−) cells than in Tsc2+/+ cells, but unlike human LAM cells, the Tsc2−/− Eker rat cells did not contain CD44v6 splice variant mRNA. CD44 splicing and signaling is regulated by osteopontin. Plasma from LAM patients contained higher concentrations of osteopontin than plasma of healthy, age-, and sex-matched volunteers (P = 0.00003) and may be a biomarker for LAM. The cell surface receptor CD44 and its splice variant CD44v6 may contribute to the metastatic potential of LAM cells. [Cancer Res 2007;67(21):10573–81]
2-Methoxyestradiol Suppresses Osteolytic Breast Cancer Tumor Progression In vivo
Authors: Cicek Muzaffer , Iwaniec Urszula T. , Goblirsch Michael J. , Vrabel Anne , Ruan Ming , Clohisy Denis R. , Turner Russell R. , Oursler Merry Jo
Published: November 2007

2-Methoxyestradiol (2ME2), a physiologic metabolite of 17β-estradiol (estrogen), has emerged as a promising cancer therapy because of its potent growth-inhibitory and proapoptotic effects on both endothelial and tumor cells. 2ME2 also suppresses osteoclast differentiation and induces apoptosis of mature osteoclasts, and has been shown to effectively repress bone loss in an animal model of postmenopausal osteoporosis. Given these observations, we have examined whether 2ME2 could effectively target metastasis to bone, osteolytic tumors, and soft tissue tumors. A 4T1 murine metastatic breast cancer cell line was generated that stably expressed Far Red fluorescence protein (4T1/Red) to visualize tumor development and metastasis to bone. In an intervention study, 4T1/Red cells were injected into bone marrow of the left femur and the mammary pad. In the latter study, 2ME2 (10, 25, and 50 mg/kg/d) treatment began on the same day as surgery and was continued for the 16-day duration of study. Tumor cell growth and metastasis to bone were monitored and bone volume was determined by micro-computed tomography. 2ME2 inhibited tumor growth in soft tissue, metastasis to bone, osteolysis, and tumor growth in bone, with maximum effects at 50 mg/kg/d. Furthermore, tumor-induced osteolysis was significantly reduced in mice receiving 2ME2. In vitro, 2ME2 repressed osteoclast number by inducing apoptosis of osteoclast precursors as well as mature osteoclasts. Our data support the conclusion that 2ME2 could be an important new therapy in the arsenal to fight metastatic breast cancer. [Cancer Res 2007;67(21):10106–11]
Differing Src Signaling Levels Have Distinct Outcomes in Drosophila
Authors: Vidal Marcos , Warner Stephen , Read Renee , Cagan Ross L.
Published: November 2007

High levels of Src activity are found in a broad spectrum of cancers. The roles of Src and its negative regulator Csk have been extensively studied, although results have often proved contradictory or the relevance to whole organisms is unclear. In Drosophila, overexpression of either Src orthologue resulted in apoptotic cell death, but paradoxically, reducing dCsk activity led to over-proliferation and tissue overgrowth. Here, we show that in Drosophila epithelia in situ, the levels of Src signaling determine the cellular outcome of Src activation. Apoptotic cell death was triggered specifically at high Src signaling levels; lower levels directed antiapoptotic signals while promoting proliferation. Furthermore, our data indicate that expression of kinase-dead Src isoforms do not necessarily act as dominant-negative factors, but can instead increase Src pathway activity, most likely by titrating Csk activity away from endogenous Src. The importance of Src activity levels was emphasized when we examined oncogenic cooperation between Src and Ras: malignant overgrowth was observed specifically when high Src signaling levels were achieved. We propose a model in which low levels of Src signaling promote survival and proliferation during early stages of tumorigenesis, whereas strong Src signaling, coupled with antiapoptotic signals, directs invasive migration and metastasis during advanced tumor stages. [Cancer Res 2007;67(21):10278–85]
Aurora-A, a Negative Prognostic Marker, Increases Migration and Decreases Radiosensitivity in Cancer Cells
Authors: Guan Zhong , Wang Xian-ren , Zhu Xiao-feng , Huang Xue-fei , Xu Jie , Wang Li-hui , Wan Xiang-bo , Long Zi-jie , Liu Jian-nan , Feng Gong-kan , Huang Wenlin , Zeng Yi-xin , Chen Fu-jin , Liu Quentin
Published: November 2007

Centrosomal Aurora-A (Aur-A) kinase ensures proper spindle assembly and accurate chromosome segregation in mitosis. Overexpression of Aur-A leads to centrosome amplification, aberrant spindle, and consequent genetic instability. In the present study, Aur-A was found to be overexpressed in laryngeal squamous cell carcinoma (LSCC). Moreover, Aur-A expression was adversely correlated with median survival, and further identified as a potential independent factor for disease prognosis. Suppression of Aurora kinase activity chemically or genetically led to LSCC Hep2 cell cycle arrest and apoptotic cell death. Importantly, we found that Aur-A increases cell migration and this novel function was correlated with Akt1 activation. The enhanced cell migration induced by Aur-A overexpression could be abrogated by either small-molecule Akt1 inhibitor or short interfering RNA. VX-680, a selective Aurora kinase inhibitor, decreased Akt1 phosphorylation at Ser473 and inhibited cell migration, but failed to do so in constitutive active Akt1 (myr-Akt1)–overexpressed cells. Moreover, our data suggested that overexpression of Aur-A kinase might also contribute to radioresistance of LSCC. Inhibiting Aur-A by VX-680 induced expression of p53 and potently sensitized cells to radiotherapy, leading to significant cell death. Ectopic overexpression of Aur-A, however, reduced p53 level and rendered cells more resistant to irradiation. Taken together, we showed that Aur-A kinase, a negative prognostic marker, promotes migration and reduces radiosensitivity in laryngeal cancer cells. [Cancer Res 2007;67(21):10436–44]
The HiNF-P/p220NPAT Cell Cycle Signaling Pathway Controls Nonhistone Target Genes
Authors: Medina Ricardo , van der Deen Margaretha , Miele-Chamberland Angela , Xie Rong-Lin , van Wijnen Andre J. , Stein Janet L. , Stein Gary S.
Published: November 2007

HiNF-P and its cofactor p220NPAT are principal factors regulating histone gene expression at the G1-S phase cell cycle transition. Here, we have investigated whether HiNF-P controls other cell cycle– and cancer-related genes. We used cDNA microarrays to monitor responsiveness of gene expression to small interfering RNA–mediated depletion of HiNF-P. Candidate HiNF-P target genes were examined for the presence of HiNF-P recognition motifs, in vitro HiNF-P binding to DNA, and in vivo association by chromatin immunoprecipitations and functional reporter gene assays. Of 177 proliferation-related genes we tested, 20 are modulated in HiNF-P–depleted cells and contain putative HiNF-P binding motifs. We validated that at least three genes (i.e., ATM, PRKDC, and CKS2) are HiNF-P dependent and provide data indicating that the DNA damage response is altered in HiNF-P–depleted cells. We conclude that, in addition to histone genes, HiNF-P also regulates expression of nonhistone targets that influence competency for cell cycle progression. [Cancer Res 2007;67(21):10334–42]
Bmi-1 Cooperates with H-Ras to Transform Human Mammary Epithelial Cells via Dysregulation of Multiple Growth-Regulatory Pathways
Authors: Datta Sonal , Hoenerhoff Mark J. , Bommi Prashant , Sainger Rachana , Guo Wei-Jian , Dimri Manjari , Band Hamid , Band Vimla , Green Jeffrey E. , Dimri Goberdhan P.
Published: November 2007

Elevated expression of Bmi-1 is associated with many cancers, including breast cancer. Here, we examined the oncogenic potential of Bmi-1 in MCF10A cells, a spontaneously immortalized, nontransformed strain of human mammary epithelial cells (HMEC). Bmi-1 overexpression alone in MCF10A cells did not result in oncogenic transformation. However, Bmi-1 co-overexpression with activated H-Ras (RasG12V) resulted in efficient transformation of MCF10A cells in vitro. Although early-passage H-Ras–expressing MCF10A cells were not transformed, late-passage H-Ras–expressing cells exhibited features of transformation in vitro. Early- and late-passage H-Ras–expressing cells also differed in levels of expression of H-Ras and Ki-67, a marker of proliferation. Subsets of early-passage H-Ras–expressing cells exhibited high Ras expression and were negative for Ki-67, whereas most late-passage H-Ras–expressing cells expressed low levels of Ras and were Ki-67 positive. Injection of late-passage H-Ras–expressing cells in severe combined immunodeficient mice formed carcinomas with leiomatous, hemangiomatous, and mast cell components; these tumors were quite distinct from those induced by late-passage cells co-overexpressing Bmi-1 and H-Ras, which formed poorly differentiated carcinomas with spindle cell features. Bmi-1 and H-Ras co-overexpression in MCF10A cells also induced features of epithelial-to-mesenchymal transition. Importantly, Bmi-1 inhibited senescence and permitted proliferation of cells expressing high levels of Ras. Examination of various growth-regulatory pathways suggested that Bmi-1 overexpression together with H-Ras promotes HMEC transformation and breast oncogenesis by deregulation of multiple growth-regulatory pathways by p16INK4a-independent mechanisms. [Cancer Res 2007;67(21):10286–95]
Estrogen Insensitivity in a Model of Estrogen Receptor–Positive Breast Cancer Lymph Node Metastasis
Authors: Harrell Joshua Chuck , Dye Wendy W. , Harvell Djuana M.E. , Pinto Mauricio , Jedlicka Paul , Sartorius Carol A. , Horwitz Kathryn B.
Published: November 2007

The lymphatic system is a common avenue for the spread of breast cancer cells and dissemination through it occurs at least as frequently as hematogenous metastasis. Approximately 75% of primary breast cancers are estrogen receptor (ER) positive and the majority of these maintain receptor expression as lymph node (LN) metastases. However, it is unknown if ER function is equivalent in cancer cells growing in the breast and in the LNs. We have developed a model to assess estrogen responsiveness in ER+ breast tumors and LN metastases. Fluorescent ER+ MCF-7 tumors were grown in ovariectomized nude mice supplemented with estradiol. Once axillary LN metastasis arose, estradiol was withdrawn (EWD), for 1 or 4 weeks, or continued, to assess estradiol responsiveness. On EWD, proliferation rates fell similarly in tumors and LN metastases. However, estradiol-dependent ER down-regulation and progesterone receptor induction were deficient in LN metastases, indicating that ER-dependent transcriptional function was altered in the LN. Cancer cells from estradiol-treated and EWD primary tumors and matched LN metastases were isolated by laser capture microdissection. Global gene expression profiling identified transcripts that were regulated by the tissue microenvironment, by hormones, or by both. Interestingly, numerous genes that were estradiol regulated in tumors lost estradiol sensitivity or were regulated in the opposite direction by estradiol in LN metastases. We propose that the LN microenvironment alters estradiol signaling and may contribute to local antiestrogen resistance. [Cancer Res 2007;67(21):10582–91]
Photodynamic Therapy Enhancement of Antitumor Immunity Is Regulated by Neutrophils
Authors: Kousis Philaretos C. , Henderson Barbara W. , Maier Patricia G. , Gollnick Sandra O.
Published: November 2007

Photodynamic therapy (PDT) is a Food and Drug Administration–approved local cancer treatment that can be curative of early disease and palliative in advanced disease. PDT of murine tumors results in regimen-dependent induction of an acute local inflammatory reaction, characterized in part by rapid neutrophil infiltration into the treated tumor bed. In this study, we show that a PDT regimen that induced a high level of neutrophilic infiltrate generated tumor-specific primary and memory CD8+ T-cell responses. In contrast, immune cells isolated from mice treated with a PDT regimen that induced little or no neutrophilic infiltrate exhibited minimal antitumor immunity. Mice defective in neutrophil homing to peripheral tissues (CXCR2−/− mice) or mice depleted of neutrophils were unable to mount strong antitumor CD8+ T-cell responses following PDT. Neutrophils seemed to be directly affecting T-cell proliferation and/or survival rather than dendritic cell maturation or T-cell migration. These novel findings indicate that by augmenting T-cell proliferation and/or survival, tumor-infiltrating neutrophils play an essential role in establishment of antitumor immunity following PDT. Furthermore, our results may suggest a mechanism by which neutrophils might affect antitumor immunity following other inflammation-inducing cancer therapies. Our findings lay the foundation for the rational design of PDT regimens that lead to optimal enhancement of antitumor immunity in a clinical setting. Immune-enhancing PDT regimens may then be combined with treatments that result in optimal ablation of primary tumors, thus inhibiting growth of primary tumor and controlling disseminated disease. [Cancer Res 2007;67(21):10501–10]
The Opioid Growth Factor (OGF)–OGF Receptor Axis Uses the p16 Pathway to Inhibit Head and Neck Cancer
Authors: Cheng Fan , Zagon Ian S. , Verderame Michael F. , McLaughlin Patricia J.
Published: November 2007

Head and neck squamous cell carcinoma (HNSCC) represents 5.5% of malignancies worldwide, with ∼30,000 new cases and ∼11,000 deaths reported in the United States annually. The opioid growth factor (OGF; [Met5]-enkephalin) and the OGF receptor (OGFr) form an endogenous growth regulating system; the OGF-OGFr axis influences the G0-G1 phase of the cell cycle in HNSCC. Cells treated with small interfering RNA (siRNA) for OGFr no longer responded to the growth inhibitory effects of OGF or the growth stimulatory effects of naltrexone, indicating that these activities are entirely mediated by OGFr. In this investigation, we examined the precise target of OGF in the cell cycle. Using SCC-1 cells, OGF decreased the phosphorylation of retinoblastoma protein. This change was correlated with reduced Cdk4, but not Cdk2, kinase activity. OGF treatment increased cyclin-dependent kinase inhibitor p16 protein expression. Importantly, p16 complexed with Cdk4 was increased by OGF treatment at all time points, consistent with the hypothesis that OGF mediated growth inhibition through p16. Blockade of OGF-OGFr interactions with naloxone abolished the increased expression of p16 protein by OGF. Inhibition of p16 (INK4a) activation by p16-specific siRNA blocked OGF's repressive action on proliferation of SCC-1, CAL-27, and SCC-4 HNSCC cells. These data are the first to reveal that the target of cell proliferative inhibitory action of OGF in human HNSCC is a cyclin-dependent kinase inhibitory pathway, and this may be useful in the diagnosis and treatment of HNSCC. [Cancer Res 2007;67(21):10511–8]
Chemotherapeutic Agents Up-regulate the Cytomegalovirus Promoter: Implications for Bioluminescence Imaging of Tumor Response to Therapy
Authors: Svensson Robert U. , Barnes J. Matthew , Rokhlin Oskar W. , Cohen Michael B. , Henry Michael D.
Published: November 2007

Bioluminescence imaging is widely used to evaluate tumor growth and response to therapy in living animals. In cells expressing luciferase under the control of a constitutive promoter, light output in part depends on viable cell number, so that changes in bioluminescence intensity may be correlated with changes in viable tumor mass over time. We have found that treatment of cancer cell lines expressing luciferase under control of the cytomegalovirus (CMV) promoter with staurosporine, doxorubicin, and paclitaxel results in a transient increase in bioluminescence, which is positively correlated with apoptosis and inversely correlated with cell viability. In contrast, similar treatment of cell lines expressing luciferase under control of the SV40 promoter did not exhibit this result. We found that low doses of staurosporine induced bioluminescence in CMV- but not SV40-driven luciferase cell lines, whereas high doses elicited induction in both, indicating promoter-dependent and promoter-independent mechanisms of bioluminescence induction. The promoter-dependent increase in bioluminescence intensity from CMV-driven luciferase is a result of induction of luciferase mRNA and protein expression. We extended these findings in vivo; doxorubicin treatment resulted in a transient induction in bioluminescence when normalized to tumor volume in CMV- but not SV40-driven luciferase-expressing xenografts. We found that inhibition of the p38 mitogen-activated protein kinase pathway blocked bioluminescence induction by doxorubicin, paclitaxel, and staurosporine in CMV-driven luciferase-expressing cells. These findings have important implications when using bioluminescence to monitor the efficacy of anticancer therapy and underscore the complex regulation of the CMV promoter, which is widely used for high-level protein expression in mammalian cells. [Cancer Res 2007;67(21):10445–54]
Keeping Out the Bad Guys: Gateway to Cellular Target Therapy
Authors: Kitamura Takanori , Taketo Makoto M.
Published: November 2007

Tumor-stromal interaction is implicated in many stages of tumor development, although it remains unclear how genetic lesions in tumor cells affect stromal cells. We have recently shown that inactivation of transforming growth factor-β family signaling within colon cancer epithelium increases chemokine CC chemokine ligand 9 (CCL9) and promotes recruitment of the matrix metalloproteinase (MMP)-expressing stromal cells that carry CC chemokine receptor 1 (CCR1), the cognate receptor for CCL9. We have further shown that lack of CCR1 prevents the accumulation of MMP-expressing cells at the invasion front and suppresses tumor invasion. These results provide the possibility of a novel therapeutic strategy for advanced cancer—prevention of the recruitment of MMP-expressing cells by chemokine receptor antagonist. [Cancer Res 2007;67(21):10099–102]
Integrative Microarray Analysis of Pathways Dysregulated in Metastatic Prostate Cancer
Authors: Setlur Sunita R. , Royce Thomas E. , Sboner Andrea , Mosquera Juan-Miguel , Demichelis Francesca , Hofer Matthias D. , Mertz Kirsten D. , Gerstein Mark , Rubin Mark A.
Published: November 2007

Microarrays have been used to identify genes involved in cancer progression. We have now developed an algorithm that identifies dysregulated pathways from multiple expression array data sets without a priori definition of gene expression thresholds. Integrative microarray analysis of pathways (IMAP) was done using existing expression array data from localized and metastatic prostate cancer. Comparison of metastatic cancer and localized disease in multiple expression array profiling studies using the IMAP approach yielded a list of about 100 pathways that were significantly dysregulated (P < 0.05) in prostate cancer metastasis. The pathway that showed the most significant dysregulation, HIV-I NEF, was validated at both the transcript level and the protein level by quantitative PCR and immunohistochemical analysis, respectively. Validation by unsupervised analysis on an independent data set using the gene expression signature from the HIV-I NEF pathway verified the accuracy of our method. Our results indicate that this pathway is especially dysregulated in hormone-refractory prostate cancer. [Cancer Res 2007;67(21):10296–303]
Local Radiotherapy Induces Homing of Hematopoietic Stem Cells to the Irradiated Bone Marrow
Authors: Bastianutto Carlo , Mian Asim , Symes Julie , Mocanu Joseph , Alajez Nehad , Sleep Gillian , Shi Wei , Keating Armand , Crump Michael , Gospodarowicz Mary , Medin Jeff , Minden Mark , Liu Fei-Fei
Published: November 2007

Local breast radiation therapy (RT) is associated with a 3-fold increased risk of secondary acute myeloid leukemia. As a first step in determining the mechanism(s) underlying this observation, we investigated the role of RT in mediating the active recruitment of hematopoietic stem cells (HSC) to the site of RT. Our results show in a mouse model that local RT delivered to the left leg causes preferential accumulation of bone marrow mononuclear cells to the irradiated site, with maximum signal intensity observed at 7 days post-RT. This is associated with a 4-fold higher number of donor-derived HSC present in the left leg, demonstrating recruitment of HSC to the site of RT. SDF-1, matrix metalloproteinase 2 (MMP-2), and MMP-9 expression is significantly increased in the irradiated bone marrow, and their inhibition significantly reduced HSC recruitment to the irradiated bone marrow. Our data show that local RT has significant systemic effects by recruiting HSC to the irradiated bone marrow site, a process mediated by SDF-1, MMP-2, and MMP-9. These results raise the possibility that the exposure of increased numbers of HSC at a local site to fractionated irradiation may increase the risk of leukemogenesis. Our data also suggest some opportunities for leukemia prevention in breast cancer patients undergoing RT. [Cancer Res 2007;67(21):10112–6]
Aneuploidy: Instigator and Inhibitor of Tumorigenesis
Authors: Weaver Beth A.A. , Cleveland Don W.
Published: November 2007

Aneuploidy, an aberrant chromosome number, has been recognized as a common characteristic of cancer cells for more than 100 years and has been suggested as a cause of tumorigenesis for nearly as long. However, this proposal had remained untested due to the difficulty of selectively generating aneuploidy without causing other damage. Using Cenp-E heterozygous animals, which develop whole chromosome aneuploidy in the absence of other defects, we have found that aneuploidy promotes tumorigenesis in some contexts and inhibits it in others. These findings confirm that aneuploidy can act oncogenically and reveal a previously unsuspected role for aneuploidy as a tumor suppressor. [Cancer Res 2007;67(21):10103–5]
Inhibition of Cyclooxygenase-2 Suppresses Lymph Node Metastasis via Reduction of Lymphangiogenesis
Authors: Iwata Caname , Kano Mitsunobu R. , Komuro Akiyoshi , Oka Masako , Kiyono Kunihiko , Johansson Erik , Morishita Yasuyuki , Yashiro Masakazu , Hirakawa Kosei , Kaminishi Michio , Miyazono Kohei
Published: November 2007

Cyclooxygenase-2 (COX-2) inhibitor has been reported to suppress tumor progression. However, it is unclear whether this inhibitor can also prevent lymphatic metastasis. To determine the effects of COX-2 inhibitor on lymphatic metastasis, etodolac, a COX-2 inhibitor, was given p.o. to mice bearing orthotopic xenografts or with carcinomatous peritonitis induced with a highly metastatic human diffuse-type gastric carcinoma cell line, OCUM-2MLN. Tumor lymphangiogenesis was significantly decreased in etodolac-treated mice compared with control mice. Consistent with this decrease in lymphangiogenesis, the total weight of metastatic lymph nodes was less in etodolac-treated mice than in control mice. Immunohistochemical analysis revealed that the major source of vascular endothelial growth factor-C (VEGF-C) and VEGF-D was F4/80-positive macrophages in our models. The mRNA levels of VEGF-C in mouse macrophage-like RAW264.7 cells, as well as those in tumor tissues, were suppressed by etodolac. The growth of human dermal lymphatic microvascular endothelial cells was also suppressed by etodolac. Supporting these findings, etodolac also inhibited lymphangiogenesis in a model of chronic aseptic peritonitis, suggesting that COX-2 can enhance lymphangiogenesis in the absence of cancer cells. Our findings suggest that COX-2 inhibitor may be useful for prophylaxis of lymph node metastasis by reducing macrophage-mediated tumor lymphangiogenesis. [Cancer Res 2007;67(21):10181–9]
Tissue-Engineered Bone Serves as a Target for Metastasis of Human Breast Cancer in a Mouse Model
Authors: Moreau Jodie E. , Anderson Kristen , Mauney Joshua R. , Nguyen Trang , Kaplan David L. , Rosenblatt Michael
Published: November 2007

The high frequency and mortality associated with breast cancer metastasis to bone has motivated efforts to elucidate tumor-stroma interactions in the bone microenvironment contributing to invasion and proliferation of metastatic cells. The development of engineered tissues has prompted the integration of engineered bone scaffolds into animal models as potential targets for metastatic spread. Silk scaffolds were coupled with bone morphogenetic protein-2 (BMP-2), seeded with bone marrow stromal cells (BMSC), and maintained in culture for 7 weeks, 4 weeks, and 1 day before s.c. implant in a mouse model of human breast cancer metastasis from the orthotopic site. Following injection of SUM1315 cells into mouse mammary fat pads, tumor burden of implanted tissues was observed only in 1-day scaffolds. Scaffold development and implantation was then reinitiated to identify the elements of the engineered bone that contribute to metastatic spread. Untreated scaffolds were compared with BMP-2–coupled, BMSC-seeded, or BMP-2/BMSC–combined treatment. Migration of SUM1315 cells was detected in four of four mice bearing scaffolds with BMP-2 treatment and with BMSC treatment, respectively, whereas only one of six mice of the BMP-2/BMSC combination showed evidence of metastatic spread. Histology confirmed active matrix modeling and stromal cell/fibroblast infiltration in scaffolds positive for the presence of metastasis. These results show the first successful integration of engineered tissues in a model system of human breast cancer metastasis. This novel platform now can be used in continued investigation of the bone environment and stem cell contributions to the process of breast cancer metastasis. [Cancer Res 2007;67(21):10304–8]
Night Shift Work and the Risk of Endometrial Cancer
Authors: Viswanathan Akila N. , Hankinson Susan E. , Schernhammer Eva S.
Published: November 2007

Melatonin has several oncostatic properties, including possible anti-estrogenic and anti-aromatase activity, and seems to be linked with fat metabolism. Night workers have lower levels of melatonin, which may predispose them to develop cancer. Endometrial cancer risk is influenced significantly by hormonal and metabolic factors; therefore, we hypothesize that night workers may have an increased risk of endometrial cancer. Of the 121,701 women enrolled in a prospective cohort study, 53,487 women provided data on rotating night shift work in 1988 and were followed through on June 1, 2004. A total of 515 women developed medical record–confirmed invasive endometrial cancer. We used Cox regression models to calculate multivariate relative risks (MVRRs), controlling for endometrial cancer risk factors. Women who worked 20+ years of rotating night shifts had a significantly increased risk of endometrial cancer [MVRR, 1.47; 95% confidence interval (95% CI), 1.03–1.14]. In stratified analyses, obese women working rotating night shifts doubled their baseline risk of endometrial cancer (MVRR, 2.09; 95% CI, 1.24–3.52) compared with obese women who did no night work, whereas a nonsignificant increase was seen among non-obese women (MVRR, 1.07; 95% CI, 0.60–1.92). Women working rotating night shifts for a long duration have a significantly increased risk of endometrial cancer, particularly if they are obese. We speculate that this increased risk is attributable to the effects of melatonin on hormonal and metabolic factors. Our results add to growing literature that suggests women who work at night may benefit from cancer prevention strategies. [Cancer Res 2007;67(21):10618–22]
Inhibition of Nuclear Factor-κB DNA Binding by Organoselenocyanates through Covalent Modification of the p50 Subunit
Authors: Chen Kun-Ming , Spratt Thomas E. , Stanley Bruce A. , De Cotiis Dan A. , Bewley Maria C. , Flanagan John M. , Desai Dhimant , Das Arunangshu , Fiala Emerich S. , Amin Shantu , El-Bayoumy Karam
Published: November 2007

Most known chemopreventive agents including certain selenium compounds suppress the activation of the nuclear factor κB (NF-κB), but the mechanisms remain largely elusive. Toward this end, we initially showed that the inhibition of NF-κB DNA binding by benzyl selenocyanate (BSC) and 1,4-phenylenebis(methylene)selenocyanate (p-XSC) was reversed by the addition of DTT; this suggests the formation of DTT-reducible selenium-sulfur bonds between selenocyanate moieties and cysteine residues in NF-κB (p50) protein. Furthermore, the inhibitory effect of selenocyanates on NF-κB was not altered in the presence of physiologic level of reduced glutathione (1 mmol/L), suggesting that selenocyanates can also inhibit NF-κB in vivo. Using both matrix-assisted laser desorption/ionization-time of flight and tandem mass spectrometry fragmentation, we showed for the first time that the Cys62 residue in the active site of NF-κB (p50) protein was modified by BSC through the formation of a selenium-sulfur bond. In addition, p-XSC–bound NF-κB (p50) protein was also detected by a radiotracer method. To provide further support, molecular models of both BSC and p-XSC positioned in the DNA binding pocket of the p50 were constructed through the covalent modification of Cys62; the models reveal that DNA substrate could be hindered to enter its DNA binding region. This study shows for the first time that BSC and p-XSC may exert their chemopreventive activity, at least in part, by inhibiting NF-κB through covalent modification of Cys62 of the p50 subunit of NF-κB. [Cancer Res 2007;67(21):10475–83]
Hypermethylation of let-7a-3 in Epithelial Ovarian Cancer Is Associated with Low Insulin-like Growth Factor-II Expression and Favorable Prognosis
Authors: Lu Lingeng , Katsaros Dionyssios , Rigault de la Longrais Irene A. , Sochirca Olga , Yu Herbert
Published: November 2007

MicroRNAs (miRNA) are endogenous noncoding small RNAs that regulate the activity of mRNAs. Many miRNA genes, including let-7a-3, are located in CpG islands, suggesting possible epigenetic regulation of their expression. Promoter CpG island methylation of tumor suppressor genes is involved in cancer development and progression. Using real-time methylation-specific PCR and real-time reverse transcription-PCR, we analyzed DNA methylation in the let-7a-3 gene and miRNA expression of let-7a in 214 patients with epithelial ovarian cancer to assess the effect of let-7a-3 methylation on the expressions of let-7a as well as a possible target of let-7 regulation, insulin-like growth factor-II (IGF-II). The association of let-7a-3 methylation with patient survival outcomes was also evaluated. let-7a-3 methylation was detected in epithelial ovarian cancer, and the expression of let-7a was slightly affected by the methylation, but the effect was not substantial. The methylation of let-7a-3, however, was inversely correlated with IGF-II expression and positively with insulin-like growth factor binding protein-3 (IGFBP-3) expression. Patients with methylated let-7a-3 seemed to have reduced risk for death compared with those without, and the association was independent of patient age at surgery, tumor grade, disease stage, and IGF-II or IGFBP-3 expression. No association was found for let-7a-3 methylation and disease progression. These results suggest that the let-7a-3 gene is methylated and the methylation may affect IGF-II expression and the survival of ovarian cancer patients. Further investigation of the role of miRNAs and their regulation in cancer is warranted. [Cancer Res 2007;67(21):10117–22]
Degradation of Lung Adenoma Susceptibility 1, a Major Candidate Mouse Lung Tumor Modifier, Is Required for Cell Cycle Progression
Authors: Liu Yan , Vikis Haris G. , Yi Yijun , Futamura Manabu , Wang Yian , You Ming
Published: November 2007

We have previously identified murine lung adenoma susceptibility 1 (Las1) as the pulmonary adenoma susceptibility 1 candidate gene. Las1 has two natural alleles, Las1-A/J and Las1-B6. Las1 encodes an 85-kDa protein with uncharacterized biological function. In the present study, we report that Las1 is an unstable protein and the rapid destruction of Las1 depends on the ubiquitin-proteasome pathway. Las1 is a new microtubule-binding protein and Las1 associated with tubulin is not ubiquitinated. We further show that Las1-A/J is a more stable protein than Las1-B6. Las1 is expressed in the G2 phase of the cell cycle and that ubiquitin-proteasome–mediated Las1 destruction occurs in mitosis. Overexpression of Las1-A/J inhibits normal E10 cell proliferation and induces a defective cytokinesis. The differential degradation of Las1-A/J and Las-B6 has important implications for its intracellular function and may eventually explain Las1-A/J in lung tumorigenesis. [Cancer Res 2007;67(21):10207–13]