bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from A Feed-Forward Loop Involving Protein Kinase Cα and MicroRNAs Regulates Tumor Cell Cycle
Authors: Cohen Ezra E.W. , Zhu Hongyan , Lingen Mark W. , Martin Leslie E. , Kuo Wen-Liang , Choi Eugene A. , Kocherginsky Masha , Parker Joel S. , Chung Christine H. , Rosner Marsha Rich
Published: March 2024

Abstract
Protein kinase Cα (PKCα) has been implicated in cancer, but the mechanism is largely unknown. Here, we show that PKCα promotes head and neck squamous cell carcinoma (SCCHN) by a feed-forward network leading to cell cycle deregulation. PKCα inhibitors decrease proliferation in SCCHN cell lines and xenografted tumors. PKCα inhibition or depletion in tumor cells decreases DNA synthesis by suppressing extracellular signal-regulated kinase phosphorylation and cyclin E synthesis. Additionally, PKCα down-regulates miR-15a, a microRNA that directly inhibits protein synthesis of cyclin E, as well as other cell cycle regulators. Furthermore, both PKCα and cyclin E protein expression are increased in primary tumors, and PKCα inversely correlates with miR-15a expression in primary tumors. Finally, PKCα is associated with poor prognosis in SCCHN. These results identify PKCα as a key regulator of SCCHN tumor cell growth by a mechanism involving activation of mitogen-activated protein kinase, an initiator of the cell cycle, and suppression of miR-15a, an inhibitor of DNA synthesis. Although the specific components may be different, this type of feed-forward loop network, consisting of a stimulus that activates a positive signal and removes a negative brake, is likely to be a general one that enables induction of DNA synthesis by a variety of growth or oncogenic stimuli. [Cancer Res 2009;69(1):65–74]
Data from Nuclear Survivin Abrogates Multiple Cell Cycle Checkpoints and Enhances Viral Oncolysis
Authors: Connell Claire M. , Wheatley Sally P. , McNeish Iain A.
Published: March 2024

Abstract
Survivin (BIRC5) promotes cell division and survival with roles as chromosomal passenger protein and inhibitor of apoptosis protein (IAP). It is overexpressed in many cancers and is associated with resistance to chemotherapy and radiation. Previously, we showed that expression of survivin within the nucleus of HeLa cells accelerates its degradation and blocks apoptosis inhibition without affecting localization during mitosis. Here, we have investigated the effects of survivin on cell cycle control and potential therapeutic consequences using HeLa and IGROV1 cells expressing wild-type and nuclear-targeted survivin. We show that overexpression of survivin, especially within the nucleus, increases control over G1-S checkpoint via increased nuclear accumulation of cyclin D and cyclin-dependent kinase 4 and subsequent pRb phosphorylation. We investigated the influence of survivin on the activity of the E1A CR2-deleted oncolytic adenovirus dl922-947, which depends critically on an aberrant G1-S checkpoint. Nuclear expression of survivin augments virus-induced S-phase induction and increases viral protein expression and overall viral replication. There is a consequent increase in antitumor activity both in vitro and in vivo. The increased dl922-947 activity is restricted to malignant cells and is not associated with induction of apoptosis, nor does it rely on the role of survivin as an IAP. In addition, we observe the appearance of a large ≥4N population coincident with multiple mitotic defects in dl922-947–infected cells, both of which are significantly increased by nuclear survivin. This indicates that adenoviral activity is facilitated by abrogation of multiple cell cycle checkpoints and can be enhanced by expression of survivin within the nucleus. [Cancer Res 2008;68(19):7923–31]
Data from Roles for MicroRNAs, miR-93 and miR-130b, and Tumor Protein 53–Induced Nuclear Protein 1 Tumor Suppressor in Cell Growth Dysregulation by Human T-Cell Lymphotrophic Virus 1
Authors: Yeung Man Lung , Yasunaga Jun-ichirou , Bennasser Yamina , Dusetti Nelson , Harris David , Ahmad Nafees , Matsuoka Masao , Jeang Kuan-Teh
Published: March 2024

Abstract
A role for microRNAs (miRNA) in human T-cell leukemia virus 1 (HTLV-1)–mediated cellular transformation has not been described. Here, we profiled miRNA expression in HTLV-1–transformed human T-cell lines and primary peripheral blood mononuclear cells from adult T-cell leukemia patients. Analyses of 11 different profiles revealed six miRNAs that were consistently up-regulated. Two of the up-regulated miRNAs (miR-93 and miR-130b) target the 3′ untranslated region (3′UTR) of the mRNA for a tumor suppressor protein, tumor protein 53–induced nuclear protein 1 (TP53INP1). A low expression level of TP53INP1 protein was found in HTLV-1–transformed cells. Additionally, when antagomirs were used to knock down miR-93 and miR-130b in these cells, the expression of TP53INP1 was increased, suggesting that the latter is regulated inside cells by the former. A role for TP53INP1 in regulating cell growth was established by experiments that showed that enhanced TP53INP1 expression increased apoptosis. Collectively, the findings implicate a miR-93/miR-130b-TP53INP1 axis that affects the proliferation and survival of HTLV-1–infected/transformed cells. [Cancer Res 2008;68(21):8976–85]
Data from Interaction between Single Nucleotide Polymorphisms in Selenoprotein P and Mitochondrial Superoxide Dismutase Determines Prostate Cancer Risk
Authors: Cooper Matthew L. , Adami Hans-Olov , Grönberg Henrik , Wiklund Fredrik , Green Fiona R. , Rayman Margaret P.
Published: March 2024

Abstract
Selenium may affect prostate cancer risk via its plasma carrier selenoprotein P which shows dramatically reduced expression in prostate cancer tumors and cell lines. The selenoprotein P (SEPP1) Ala234 single nucleotide polymorphism (SNP) allele is associated with lower plasma selenoprotein P in men, reducing the concentration/activity of other antioxidant selenoproteins. Selenium status also modifies the effect of the mitochondrial superoxide dismutase (SOD2) SNP Ala16Val on prostate cancer risk. We investigated the relationship of these SNPs with prostate cancer risk. DNA from 2,975 cases and 1,896 age-matched controls from the population-based Prostate Cancer in Sweden study were genotyped using TaqMan assays. Cases were designated aggressive or nonaggressive prostate cancers at diagnosis by clinical criteria. Association with prostate cancer was investigated by logistic regression; gene-gene interaction using a general linear model. The mean plasma selenium concentration measured in 169 controls was relatively low (76.0 ± 17.2 μg/L). SNP genotype distributions were in Hardy-Weinberg equilibrium. SOD2-Ala16+ men were at a greater risk of prostate cancer [odds ratios (OR), 1.19; 95% confidence intervals (CI), 1.03–1.37] compared with SOD2-Val16 homozygotes. Men homozygous for SEPP1-Ala234 who were also SOD2-Ala16+ had a higher risk of prostate cancer (OR, 1.43; 95% CI, 1.17–1.76) and aggressive prostate cancer (OR, 1.60; 95% CI, 1.22–2.09) than those who were SOD2-Val16 homozygotes (interaction, prostate cancer P = 0.05; aggressive prostate cancer P = 0.01). This interaction was stronger in ever-smokers: SOD2-Ala16+ men homozygous for SEPP1-Ala234 had an almost doubled risk of prostate cancer (OR, 1.97; 95% CI, 1.33–2.91; interaction P = 0.001). In a low-selenium population, SOD2-Ala16+ men homozygous for SEPP1-Ala234 are at an increased risk of prostate cancer/aggressive prostate cancer especially if ever-smokers, because they are likely to produce more mitochondrial H2O2 that they cannot remove, thereby promoting prostate tumor cell proliferation and migration. [Cancer Res 2008;68(24):10171–7]
Data from Genetic Regulation of the Response to Her-2 DNA Vaccination in Human Her-2 Transgenic Mice
Authors: Radkevich-Brown Olga , Jacob Jennifer , Kershaw Michael , Wei Wei-Zen
Published: March 2024

Abstract
Genetic regulation of immune reactivity to Her-2 vaccination and the consequent antitumor effect was tested in human Her-2 transgenic (Tg) mice of C57BL/6 (B6), BALB/c (BALB), and (B6x BALB) F1 (F1) background. Mice were electrovaccinated with Her-2 DNA with or without pretreatment with CD25 monoclonal antibody to remove CD25hi regulatory T cells. When CD25+ T cells were intact, BALB Her-2 Tg mice were more responsive than the other two strains in both humoral and cellular immunities, and their tumor growth was significantly delayed. B6 Her-2 Tg mice responded poorly and F1 mice showed modest immune reactivity, but tumor growth did not change in either strain. Depletion of CD25hi T cells before vaccination significantly improved protection from tumor challenge in F1 Her-2 Tg mice. This was associated with elevated levels of Her-2 IgG1, IgG2a, and IgG2c antibodies, and some mice also showed IFN-γ producing T-cell response. The same treatment induced modest improvement in B6 Her-2 Tg mice. In BALB Her-2 Tg mice, however, depletion of CD25hi T cells did not further improve antitumor efficacy. Although their Her-2–specific IgG1 and interleukin-5–secreting T cells increased, the levels of IgG2a and IFN-γ–secreting T cells did not change. These results are the first to show genetic regulation of the response to a cancer vaccine and an unequal effect of removing CD25hi T cells on antitumor immunity. These results warrant individualized treatment plans for patients with heterogeneous genetic backgrounds and possibly differential intrinsic immune reactivity to tumor antigens. [Cancer Res 2009;69(1):212–8]
Data from Natural Killer Cell Accumulation in Tumors Is Dependent on IFN-γ and CXCR3 Ligands
Authors: Wendel Marco , Galani Ioanna E. , Suri-Payer Elisabeth , Cerwenka Adelheid
Published: March 2024

Abstract
Several studies have correlated high numbers of tumor-infiltrating natural killer (NK) cells with a good prognosis for cancer patients. Our study aimed at identifying factors controlling intratumoral NK cell accumulation in s.c. injected NK cell sensitive tumor models and at studying their effect on survival time of recipient mice. We observed that fewer NK cells infiltrated the tumors in IFN-γ receptor knockout (IFN-γR−/−) mice compared with wild-type controls that correlated with decreased survival rate. Exogenous application of IFN-γ in the tumor augmented levels of ligands of the chemokine receptor CXCR3, increased NK cell accumulation, and prolonged survival. Furthermore, our data show that CD27high NK cells, which under steady-state conditions express CXCR3, preferentially accumulated in the tumor tissue. Accordingly, significantly lower numbers of tumor-infiltrating NK cells were detected in CXCR3−/− mice, and the capacity of adoptively transferred CXCR3−/− NK cells to accumulate in the tumor was severely impaired. Finally, exogenous application of the CXCR3 ligand CXCL10 in the tumor or ectopic expression of CXCL10 by tumor cells increased the numbers of NK cells in the tumors and prolonged NK cell–dependent survival. Our results identify IFN-γ and the expression of CXCR3 on NK cells as prerequisites for NK cell infiltration into tumors. Exploiting strategies to augment NK cell accumulation in the tumor might lead to the development of effective antitumor therapies. [Cancer Res 2008;68(20):8437–45]
Data from Interleukin 21 Enhances Antibody-Mediated Tumor Rejection
Authors: Smyth Mark J. , Teng Michele W.L. , Sharkey Janelle , Westwood Jennifer A. , Haynes Nicole M. , Yagita Hideo , Takeda Kazuyoshi , Sivakumar Pallavur V. , Kershaw Michael H.
Published: March 2024

Abstract
Interleukin-21 (IL-21) is a cytokine with structural and sequence homology to IL-2 and IL-15 that has antitumor activity alone in mouse experimental tumor models and a tolerable safety profile in phase I trials in patients with metastatic melanoma and renal cell carcinoma. Several monoclonal antibodies (mAb) targeted at tumor-associated antigens also have improved antitumor activities in mice when used in combination with IL-21. Recently, we described a rational three antibody-based approach (triple mAb, TrimAb) to eradicating established mouse tumors that required the generation of tumor-reactive CD8+ T cells and IFN-γ. Herein, we show that sequentially combining TrimAb with recombinant IL-21 can significantly improve the antitumor activity of this combination against very advanced disease. These data further support the use of IL-21 in adjuvant settings where strong T cell–mediated immune responses to tumors can be generated. [Cancer Res 2008;68(8):3019–25]
Data from Activation of Phosphatidylinositol 3-Kinase by Membrane Localization of p110α Predisposes Mammary Glands to Neoplastic Transformation
Authors: Renner Oliver , Blanco-Aparicio Carmen , Grassow Maja , Cañamero Marta , Leal Juan F.M. , Carnero Amancio
Published: March 2024

Abstract
Phosphatidylinositol 3-kinases (PI3K) constitute important regulators of various signaling pathways with relevance in cancer. Enhanced activation of p110α, the catalytic subunit of PI3K, was found in a high proportion of many human tumor types. We generated a mouse model in which PI3K is activated by forced recruitment of p110α to the membrane. Different transgenic lines expressing myristoylated p110α protein under the control of the epithelial-specific mouse mammary tumor virus promoter were selected according to different levels of PI3K activity and characterized. Delayed mammary gland involution and morphologic changes of the mammary ducts could be detected in young transgenic female mice. These changes were more pronounced in old animals, especially in mutiparous females, in which we observed increased ductal branching, alveolar hyperplasia, and intraductal neoplasia. We also observed a small percentage of mammary tumors. Crosses of myrp110α transgenic mice with heterozygous p53(+/−) knockout mice resulted in neither enhanced tumorigenesis nor in a stronger mammary gland phenotype. However, the CDK4 activating mutation (R24C) lead to increased tumorigenesis in transgenic myrp110α mice, emphasizing the postulated perturbation of the interaction of the CDK4/Rb/E2F cascade and the PI3K signaling in many human cancers. Interestingly, in tumors of myrp110α transgenic mice, we observed an increased phosphorylation of the estrogen receptor-α, a typical feature of human breast cancer. The model presented here will help to discover additional factors which influence the progression of preneoplastic lesions to tumors in the mammary gland and to explore antitumor therapies based on PI3K or estrogen receptor-α pathway inhibition. [Cancer Res 2008;68(23):9643–53]
Data from Palomid 529, a Novel Small-Molecule Drug, Is a TORC1/TORC2 Inhibitor That Reduces Tumor Growth, Tumor Angiogenesis, and Vascular Permeability
Authors: Xue Qi , Hopkins Benjamin , Perruzzi Carole , Udayakumar Durga , Sherris David , Benjamin Laura E.
Published: March 2024

Abstract
It has become clear that the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is central for promoting both tumor and tumor stroma and is therefore a major target for anticancer drug development. First- and second-generation rapalogs (prototypical mTOR inhibitors) have shown promise but, due to the complex nature of mTOR signaling, can result in counterproductive feedback signaling to potentiate upstream Akt signaling. We present a novel PI3K/Akt/mTOR inhibitor, Palomid 529 (P529), which inhibits the TORC1 and TORC2 complexes and shows both inhibition of Akt signaling and mTOR signaling similarly in tumor and vasculature. We show that P529 inhibits tumor growth, angiogenesis, and vascular permeability. It retains the beneficial aspects of tumor vascular normalization that rapamycin boasts. However, P529 has the additional benefit of blocking pAktS473 signaling consistent with blocking TORC2 in all cells and thus bypassing feedback loops that lead to increased Akt signaling in some tumor cells. [Cancer Res 2008;68(22):9551–7]
Data from Genomic Alterations Indicate Tumor Origin and Varied Metastatic Potential of Disseminated Cells from Prostate Cancer Patients
Authors: Holcomb Ilona N. , Grove Douglas I. , Kinnunen Martin , Friedman Cynthia L. , Gallaher Ian S. , Morgan Todd M. , Sather Cassandra L. , Delrow Jeffrey J. , Nelson Peter S. , Lange Paul H. , Ellis William J. , True Lawrence D. , Young Janet M. , Hsu Li , Trask Barbara J. , Vessella Robert L.
Published: March 2024

Abstract
Disseminated epithelial cells can be isolated from the bone marrow of a far greater fraction of prostate-cancer patients than the fraction of patients who progress to metastatic disease. To provide a better understanding of these cells, we have characterized their genomic alterations. We first present an array comparative genomic hybridization method capable of detecting genomic changes in the small number of disseminated cells (10–20) that can typically be obtained from bone marrow aspirates of prostate-cancer patients. We show multiple regions of copy-number change, including alterations common in prostate cancer, such as 8p loss, 8q gain, and gain encompassing the androgen-receptor gene on Xq, in the disseminated cell pools from 11 metastatic patients. We found fewer and less striking genomic alterations in the 48 pools of disseminated cells from patients with organ-confined disease. However, we identify changes shared by these samples with their corresponding primary tumors and prostate-cancer alterations reported in the literature, evidence that these cells, like those in advanced disease, are disseminated tumor cells (DTC). We also show that DTCs from patients with advanced and localized disease share several abnormalities, including losses containing cell-adhesion genes and alterations reported to associate with progressive disease. These shared alterations might confer the capability to disseminate or establish secondary disease. Overall, the spectrum of genomic deviations is evidence for metastatic capacity in advanced-disease DTCs and for variation in that capacity in DTCs from localized disease. Our analysis lays the foundation for elucidation of the relationship between DTC genomic alterations and progressive prostate cancer. [Cancer Res 2008;68(14):5599–608]
Data from ICAM-1 Has a Critical Role in the Regulation of Metastatic Melanoma Tumor Susceptibility to CTL Lysis by Interfering with PI3K/AKT Pathway
Authors: Hamaï Ahmed , Meslin Franck , Benlalam Houssem , Jalil Abdelali , Mehrpour Maryam , Faure Florence , Lecluse Yann , Vielh Philipe , Avril Marie-Françoise , Robert Caroline , Chouaib Salem
Published: March 2024

Abstract
Human primary melanoma cells (T1) were found to be more susceptible to lysis by a Melan-A/MART-1–specific CTL clone (LT12) than their metastatic derivative (G1). We show that this differential susceptibility does not involve antigen presentation by target cells, synapse formation between the metastatic target and CTL clone, or subsequent granzyme B (GrB) polarization. Although PI-9, an inhibitor of GrB, was found to be overexpressed in metastatic G1 cells, knockdown of the PI-9 gene did not result in the attenuation of G1 resistance to CTL-induced killing. Interestingly, we show that whereas T1 cells express high levels of intercellular adhesion molecule-1 (ICAM-1), a dramatically reduced expression was noted on G1 cells. We also showed that sorted ICAM-1+ G1 cells were highly sensitive to CTL-induced lysis compared with ICAM-1− G1 cells. Furthermore, incubation of metastatic G1 cells with IFN-γ resulted in the induction of ICAM-1 and the potentiation of their susceptibility to lysis by LT12. More importantly, we found that the level of ICAM-1 expression by melanoma cells correlated with decreased PTEN activity. ICAM-1 knockdown in T1 cells resulted in increased phosphorylation of PTEN and the subsequent activation of AKT. We have additionally shown that inhibition of the phosphatidylinositol (3,4,5)-triphosphate kinase (PI3K)/AKT pathway by the specific inhibitor wortmannin induced a significant potentiation of susceptibility of G1 and ICAM-1 small interfering RNA–treated T1 cells to CTL-induced lysis. The present study shows that a shift in ICAM-1 expression, which was associated with an activation of the PI3K/AKT pathway, can be used by metastatic melanoma cells to escape CTL-mediated killing. [Cancer Res 2008;68(23):9854–64]
Data from BCR/ABL and Other Kinases from Chronic Myeloproliferative Disorders Stimulate Single-Strand Annealing, an Unfaithful DNA Double-Strand Break Repair
Authors: Cramer Kimberly , Nieborowska-Skorska Margaret , Koptyra Mateusz , Slupianek Artur , Penserga Emir Tyrone P. , Eaves Connie J. , Aulitzky Walter , Skorski Tomasz
Published: March 2024

Abstract
Myeloproliferative disorders (MPD) are stem cell–derived clonal diseases arising as a consequence of acquired aberrations in c-ABL, Janus-activated kinase 2 (JAK2), and platelet-derived growth factor receptor (PDGFR) that generate oncogenic fusion tyrosine kinases (FTK), including BCR/ABL, TEL/ABL, TEL/JAK2, and TEL/PDGFβR. Here, we show that FTKs stimulate the formation of reactive oxygen species and DNA double-strand breaks (DSB) both in hematopoietic cell lines and in CD34+ leukemic stem/progenitor cells from patients with chronic myelogenous leukemia (CML). Single-strand annealing (SSA) represents a relatively rare but very unfaithful DSB repair mechanism causing chromosomal aberrations. Using a specific reporter cassette integrated into genomic DNA, we found that BCR/ABL and other FTKs stimulated SSA activity. Imatinib-mediated inhibition of BCR/ABL abrogated this effect, implicating a kinase-dependent mechanism. Y253F, E255K, T315I, and H396P mutants of BCR/ABL that confer imatinib resistance also stimulated SSA. Increased expression of either nonmutated or mutated BCR/ABL kinase, as is typical of blast phase cells and very primitive chronic phase CML cells, was associated with higher SSA activity. BCR/ABL-mediated stimulation of SSA was accompanied by enhanced nuclear colocalization of RAD52 and ERCC1, which play a key role in the repair. Taken together, these findings suggest a role of FTKs in causing disease progression in MPDs by inducing chromosomal instability through the production of DSBs and stimulation of SSA repair. [Cancer Res 2008;68(17):6884–8]
Data from Chemoprevention and Treatment of Experimental Cowden's Disease by mTOR Inhibition with Rapamycin
Authors: Squarize Cristiane H. , Castilho Rogerio M. , Gutkind J. Silvio
Published: March 2024

Abstract
Cowden's disease is an autosomal dominant disorder characterized by the development of multiple mucocutaneous lesions and benign tumors, and enhanced cancer predisposition. Most Cowden's disease patients harbor inactivating mutations in the PTEN tumor suppressor gene which encodes a lipid phosphatase, PTEN, which restrains the phosphatidylinositol 3-kinase–Akt signaling pathway. We observed that the epithelial-specific deletion of Pten in mice causes multiple hyperproliferative and tumor lesions that strikingly resemble Cowden's disease. This animal model system provided an opportunity to explore novel therapeutic approaches in Cowden's disease. Indeed, we show here that rapamycin administration, which inhibits a key downstream target of Akt, mammalian target of rapamycin (mTOR), promotes the rapid regression of advanced mucocutaneous lesions. Furthermore, when administered before disease manifestation, rapamycin can halt the development of Cowden's disease–like lesions, thereby prolonging animal survival. These findings suggest that mTOR inhibition with rapamycin may represent a suitable therapeutic option for the chemoprevention and treatment of Cowden disease patients and others tumor syndromes that involve defective PTEN function. [Cancer Res 2008;68(17):7066–72]
Data from Association Study of Prostate Cancer Susceptibility Variants with Risks of Invasive Ovarian, Breast, and Colorectal Cancer
Authors: Song Honglin , Koessler Thibaud , Ahmed Shahana , Ramus Susan J. , Kjaer Susanne Krüger , DiCioccio Richard A. , Wozniak Eva , Hogdall Estrid , Whittemore Alice S. , McGuire Valerie , Ponder Bruce A.J. , Turnbull Clare , Hines Sarah , Rahman Nazneen , Eeles Rosalind A. , Easton Douglas F. , Gayther Simon A. , Dunning Alison M. , Pharoah Paul D.P.
Published: March 2024

Abstract
Several prostate cancer susceptibility loci have recently been identified by genome-wide association studies. These loci are candidates for susceptibility to other epithelial cancers. The aim of this study was to test these tag single nucleotide polymorphisms (SNP) for association with invasive ovarian, colorectal, and breast cancer. Twelve prostate cancer–associated tag SNPs were genotyped in ovarian (2,087 cases/3,491 controls), colorectal (2,148 cases/2,265 controls) and breast (first set, 4,339 cases/4,552 controls; second set, 3,800 cases/3,995 controls) case-control studies. The primary test of association was a comparison of genotype frequencies between cases and controls, and a test for trend stratified by study where appropriate. Genotype-specific odds ratios (OR) were estimated by logistic regression. SNP rs2660753 (chromosome 3p12) showed evidence of association with ovarian cancer [per minor allele OR, 1.19; 95% confidence interval (95% CI), 1.04–1.37; Ptrend = 0.012]. This association was stronger for the serous histologic subtype (OR, 1.29; 95% CI, 1.09–1.53; P = 0.003). SNP rs7931342 (chromosome 11q13) showed some evidence of association with breast cancer (per minor allele OR, 0.95; 95% CI, 0.91–0.99; Ptrend = 0.028). This association was somewhat stronger for estrogen receptor–positive tumors (OR, 0.92; 95% CI, 0.87–0.98; P = 0.011). None of these tag SNPs were associated with risk of colorectal cancer. In conclusion, loci associated with risk of prostate cancer may also be associated with ovarian and breast cancer susceptibility. However, the effects are modest and warrant replication in larger studies. [Cancer Res 2008;68(21):8837–42]
Data from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation
Authors: McCabe Michael T. , Lee Eva K. , Vertino Paula M.
Published: March 2024

Abstract
Aberrant CpG island methylation is associated with transcriptional silencing of regulatory genes in human cancer. Although most CpG islands remain unmethylated, a subset accrues aberrant methylation in cancer via unknown mechanisms. Previously, we showed that CpG islands differ in their intrinsic propensity towards hypermethylation. We developed a classifier (PatMAn) based on the frequencies of seven DNA sequence patterns that discriminated methylation-prone (MP) and methylation-resistant (MR) CpG islands. Here, we report on the genome-wide application and direct testing of PatMAn in cancer. Although trained on data from a cell culture model of de novo methylation involving the overexpression of DNMT1, PatMAn accurately predicted CpG islands at increased risk of hypermethylation in cancer cell lines and primary tumors. Analysis of CpG islands predicted to be MP revealed a strong association with embryonic targets of polycomb-repressive complex 2 (PRC2), indicating that PatMAn predicts not only aberrant methylation, but also PRC2 binding. A second classifier (SUPER-PatMAn) that integrates the seven PatMAn DNA patterns with SUZ12 enriched regions as a marker of PRC2 occupancy showed improved performance (prediction accuracy, 81–88%). In addition to many non-PRC2 targets, SUPER-PatMAn identified a subset of PRC2 targets that were more likely to be hypermethylated in cancer. Genome-wide, CpG islands predicted to be MP were enriched in genes known to undergo hypermethylation in cancer, genes functioning in transcriptional regulation, and components of developmental pathways. These findings show that hypermethylation of certain gene loci is controlled in part by an underlying susceptibility influenced by both local sequence context and trans-acting factors. [Cancer Res 2009;69(1):282–91]
Data from Transient Nutlin-3a Treatment Promotes Endoreduplication and the Generation of Therapy-Resistant Tetraploid Cells
Authors: Shen Hong , Moran Diarmuid M. , Maki Carl G.
Published: March 2024

Abstract
p53 activity is controlled in large part by MDM2, an E3 ubiquitin ligase that binds p53 and promotes its degradation. The MDM2 antagonist Nutlin-3a stabilizes p53 by blocking its interaction with MDM2. Several studies have supported the potential use of Nutlin-3a in cancer therapy. Two different p53 wild-type cancer cell lines (U2OS and HCT116) treated with Nutlin-3a for 24 hours accumulated 2N and 4N DNA content, suggestive of G1 and G2 phase cell cycle arrest. This coincided with increased p53 and p21 expression, hypophosphorylation of pRb, and depletion of Cyclin B1, Cyclin A, and CDC2. Upon removal of Nutlin-3a, 4N cells entered S phase and re-replicated their DNA without an intervening mitotic division, a process known as endoreduplication. p53-p21 pathway activation was required for the depletion of Cyclin B1, Cyclin A, and CDC2 in Nutlin-3a–treated cells and for endoreduplication after Nutlin-3a removal. Stable tetraploid clones could be isolated from Nutlin-3a treated cells, and these tetraploid clones were more resistant to ionizing radiation and cisplatin-induced apoptosis than diploid counterparts. These data indicate that transient Nutlin-3a treatment of p53 wild-type cancer cells can promote endoreduplication and the generation of therapy-resistant tetraploid cells. These findings have important implications regarding the use of Nutlin-3a in cancer therapy.[Cancer Res 2008;68(20):8260–8]
Data from The Peptidyl-Isomerase Pin1 Regulates p27kip1 Expression through Inhibition of Forkhead Box O Tumor Suppressors
Authors: Brenkman Arjan B. , de Keizer Peter L.J. , van den Broek Niels J.F. , van der Groep Petra , van Diest Paul J. , van der Horst Armando , Smits Alida M.M. , Burgering Boudewijn M.T.
Published: March 2024

Abstract
The Forkhead box O (FOXO) protein family is an evolutionarily conserved subclass of transcription factors recently identified as bona fide tumor suppressors. Preventing the accumulation of cellular damage due to oxidative stress is thought to underlie its tumor-suppressive role. Oxidative stress, in turn, also feedback controls FOXO4 function. Regulation of this process, however, is poorly understood but may be relevant to the ability of FOXO to control tumor suppression. Here, we characterize novel FOXO4 phosphorylation sites after increased cellular oxidative stress and identify the isomerase Pin1, a protein frequently found to be overexpressed in cancer, as a critical regulator of p27kip1 through FOXO4 inhibition. We show that Pin1 requires these phosphorylation events to act negatively on FOXO4 transcriptional activity. Consistent with this, oxidative stress induces binding of Pin1 to FOXO, thereby attenuating its monoubiquitination, a yet uncharacterized mode of substrate modulation by Pin1. We have previously shown that monoubiquitination is involved in controlling nuclear translocation in response to cellular stress, and indeed, Pin1 prevents nuclear FOXO4 accumulation. Interestingly, Pin1 acts on FOXO through stimulation of the activity of the deubiquitinating enzyme HAUSP/USP7. Ultimately, this results in decreased transcriptional activity towards target genes, including the cell cycle arrest gene p27kip1. Notably, in a primary human breast cancer panel, low p27kip1 levels inversely correlated with Pin1 expression. Thus, Pin1 is identified as a novel negative FOXO regulator, interconnecting FOXO phosphorylation and monoubiquitination in response to cellular stress to regulate p27kip1. [Cancer Res 2008;68(18):7597–605]
Data from Targeting Focal Adhesion Kinase with Dominant-Negative FRNK or Hsp90 Inhibitor 17-DMAG Suppresses Tumor Growth and Metastasis of SiHa Cervical Xenografts
Authors: Schwock Joerg , Dhani Neesha , Cao Mary Ping-Jiang , Zheng Jinzi , Clarkson Richard , Radulovich Nikolina , Navab Roya , Horn Lars-Christian , Hedley David W.
Published: March 2024

Abstract
Focal adhesion kinase (FAK), a nonreceptor protein tyrosine kinase and key modulator of integrin signaling, is widely expressed in different tissues and cell types. Recent evidence indicates a central function of FAK in neoplasia where the kinase contributes to cell proliferation, resistance to apoptosis and anoikis, invasiveness, and metastasis. FAK, like other signaling kinases, is dependent on the chaperone heat shock protein 90 (Hsp90) for its stability and proper function. Thus, inhibition of Hsp90 might be a way of disrupting FAK signaling and, consequently, tumor progression. FAK is expressed in high-grade squamous intraepithelial lesions and metastatic cervical carcinomas but not in nonneoplastic cervical mucosa. In SiHa, a cervical cancer cell line with characteristics of epithelial-to-mesenchymal transition, the stable expression of dominant-negative FAK-related nonkinase decreases anchorage independence and delays xenograft growth. FAK-related nonkinase as well as the Hsp90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin both negatively interfere with FAK signaling and focal adhesion turnover. Short-term 17-dimethylaminoethylamino-17-demethoxygeldanamycin treatment prolongs survival in a SiHa lung metastasis model and chronic administration suppresses tumor growth as well as metastatic spread in orthotopic xenografts. Taken together, our data suggest that FAK is of importance for tumor progression in cervical cancer and that disruption of FAK signaling by Hsp90 inhibition might be an avenue to restrain tumor growth as well as metastatic spread. [Cancer Res 2009;69(11):4750–9]
Data from Opposite Effects of Notch-1 and Notch-2 on Mesothelioma Cell Survival under Hypoxia Are Exerted through the Akt Pathway
Authors: Graziani Irene , Eliasz Sandra , De Marco Melissa A. , Chen Yuanbin , Pass Harvey I. , De May Richard M. , Strack Peter R. , Miele Lucio , Bocchetta Maurizio
Published: March 2024

Abstract
Malignant mesothelioma (MM) is a cancer of the lining of the lungs, heart, and intestine and is known to respond poorly to chemotherapy. Here we show that malignant mesothelial cells have an elevated Notch signaling pathway compared with normal human mesothelial cells. We studied the role of Notch in MM under normoxic and hypoxic conditions, the latter condition best recapitulating the MM microenvironment. Genetic and chemical modulation of the Notch pathway indicated that MM cells are dependent on Notch signaling. More specifically, this signaling was Notch-1 dependent as the result of its negative transcriptional regulation on phosphatase and tensin homologue (PTEN), which led to activation of the prosurvival phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway. Our study also provides evidence that whereas Notch-1 is elevated in the malignant setting, Notch-2 is diminished. This differential expression of the two Notch isoforms benefits cancer cell survival because reexpression of Notch-2 was toxic to MM cells. The mechanism of Notch-2 toxicity to MM cells countered that of Notch-1, as it was the result of positive transcriptional regulation of PTEN and inhibition of the PI3K/Akt/mTOR signaling pathway. These results provide new insight into the role of Notch in MM and suggest that Notch pathway inhibitors may be useful in the treatment of this deadly disease. [Cancer Res 2008;68(23):9678–85]
Data from Characterization of Naturally Occurring HPV16 Integration Sites Isolated from Cervical Keratinocytes under Noncompetitive Conditions
Authors: Dall Keltie L. , Scarpini Cinzia G. , Roberts Ian , Winder David M. , Stanley Margaret A. , Muralidhar Balaji , Herdman M. Trent , Pett Mark R. , Coleman Nicholas
Published: March 2024

Abstract
As the high-risk human papillomavirus (HPV) integrants seen in anogenital carcinomas represent the end-point of a clonal selection process, we used the W12 model to study the naturally occurring integration events that exist in HPV16-infected cervical keratinocytes before integrant selection. We performed limiting dilution cloning to identify integrants present in cells that also maintain episomes. Such integrants arise in a natural context and exist in a noncompetitive environment, as they are transcriptionally repressed by episome-derived E2. We found that integration can occur at any time during episome maintenance, providing biological support for epidemiologic observations that persistent HPV infection is a major risk factor in cervical carcinogenesis. Of 24 different integration sites isolated from a single nonclonal population of W12, 12 (50%) occurred within chromosome bands containing a common fragile site (CFS), similar to observations for selected integrants in vivo. This suggests that such regions represent relatively accessible sites for insertion of foreign DNA, rather than conferring a selective advantage when disrupted. Interestingly, however, integrants and CFSs did not accurately colocalize. We further observed that local DNA rearrangements occur frequently and rapidly after the integration event. The majority of integrants were in chromosome bands containing a cancer-associated coding gene or microRNA, indicating that integration occurs commonly in these regions, regardless of selective pressure. The cancer-associated genes were generally a considerable distance from the integration site, and there was no evidence for altered expression of nine strong candidate genes. These latter observations do not support an important role for HPV16 integration in causing insertional mutagenesis. [Cancer Res 2008;68(20):8249–59]
Data from MicroRNAs Impair MET-Mediated Invasive Growth
Authors: Migliore Cristina , Petrelli Annalisa , Ghiso Elena , Corso Simona , Capparuccia Lorena , Eramo Adriana , Comoglio Paolo M. , Giordano Silvia
Published: March 2024

Abstract
MicroRNAs (miRNA) are a recently identified class of noncoding, endogenous, small RNAs that regulate gene expression, mainly at the translational level. These molecules play critical roles in several biological processes, such as cell proliferation and differentiation, development, and aging. It is also known that miRNAs play a role in human cancers where they can act either as oncogenes, down-regulating tumor suppressor genes, or as onco-suppressors, targeting molecules critically involved in promotion of tumor growth. One of such molecules is the tyrosine kinase receptor for hepatocyte growth factor, encoded by the MET oncogene. The MET receptor promotes a complex biological program named “invasive growth” that results from stimulation of cell motility, invasion, and protection from apoptosis. This oncogene is deregulated in many human tumors, where its most frequent alteration is overexpression. In this work, we have identified three miRNAs (miR-34b, miR-34c, and miR-199a*) that negatively regulate MET expression. Inhibition of these endogenous miRNAs, by use of antagomiRs, resulted in increased expression of MET protein, whereas their exogenous expression in cancer cells blocked MET-induced signal transduction and the execution of the invasive growth program, both in cells expressing normal levels of MET and in cancer cells overexpressing a constitutively active MET. Moreover, we show that these same miRNAs play a role in regulating the MET-induced migratory ability of melanoma-derived primary cells. In conclusion, we have identified miRNAs that behave as oncosuppressors by negatively targeting MET and might thus provide an additional option to inhibit this oncogene in tumors displaying its deregulation. [Cancer Res 2008;68(24):10128–36]
Data from The Mitogen-Activated Protein Kinase Phosphatase Vaccinia H1–Related Protein Inhibits Apoptosis in Prostate Cancer Cells and Is Overexpressed in Prostate Cancer
Authors: Arnoldussen Yke Jildouw , Lorenzo Petra I. , Pretorius Maria E. , Wæhre Håkon , Risberg Bjørn , Mælandsmo Gunhild M. , Danielsen Håvard E. , Saatcioglu Fahri
Published: March 2024

Abstract
Androgen ablation during the initial stages of prostate cancer causes regression of the tumor due to an increase in apoptosis and reduced cellular proliferation. However, prostate cancer invariably progresses to an androgen-independent state for poorly understood reasons. Previous studies showed that c-Jun NH2 terminal kinase (JNK) is required for 12-O-tetradecanoylphorbol-13-acetate (TPA)– and thapsigargin (TG)–induced apoptosis in the androgen-responsive prostate cancer cell line LNCaP. Androgens protect LNCaP cells from TPA-induced or TG-induced apoptosis via down-regulation of JNK activation. However, the molecular mechanisms of this inhibition are not clear. Here, we systematically investigated the possible regulation of mitogen-activated protein kinase phosphatases/dual-specificity phosphatases during apoptosis of LNCaP cells and found that Vaccinia H1–related protein (VHR/DUSP3) is up-regulated by androgens during inhibition of apoptosis in LNCaP cells, but not in androgen-independent DU145 cells. Ectopic expression of wild-type VHR, but not a catalytically inactive mutant, interfered with TPA- and TG-induced apoptosis. Consistently, small interfering RNA–mediated knockdown of endogenous VHR increased apoptosis in response to TPA or TG in the presence of androgens. Furthermore, COS7 cells stably expressing wild-type VHR, but not a mutant, had a decrease in JNK phosphorylation. In vivo, VHR expression decreased in the androgen-dependent human prostate cancer xenograft CWR22 upon androgen withdrawal and was inversely correlated to JNK phosphorylation. Expression analysis in human prostate cancer specimens showed that VHR is increased in prostate cancer compared with normal prostate. These data show that VHR has a direct role in the inhibition of JNK-dependent apoptosis in LNCaP cells and may therefore have a role in prostate cancer progression. [Cancer Res 2008;68(22):9255–64]
Data from Identification of Let-7–Regulated Oncofetal Genes
Authors: Boyerinas Benjamin , Park Sun-Mi , Shomron Noam , Hedegaard Mads M. , Vinther Jeppe , Andersen Jens S. , Feig Christine , Xu Jinbo , Burge Christopher B. , Peter Marcus E.
Published: March 2024

Abstract
MicroRNAs (miRNA) are small RNA molecules of ∼20 to 22 nucleotides that reduce expression of proteins through mRNA degradation and/or translational silencing. Each known miRNA has a large number of predicted targets. Members of the let-7/miR-98 family of miRNAs are up-regulated at the end of embryonic development. Let-7 is often down-regulated early during cancer development, suggesting that let-7–regulated oncofetal genes (LOG) may become reexpressed in cancer cells. Using comparative bioinformatics, we have identified 12 conserved LOGs that include HMGA2 and IMP-1/CRD-BP. IMP-1 has growth-promoting activities through stabilization of c-myc mRNA. We experimentally confirmed that IMP-1 is a direct let-7 target that promotes cell growth and motility of tumor cells, and we confirmed by proteomics analysis that IMP-1 and HMGA2 are major miRNA targets. Our data suggest that a substantial part of the growth inhibitory activities of let-7 comes from suppressing the expression of IMP-1. LOGs could be novel therapeutic targets and potential biomarkers for cancer treatment. [Cancer Res 2008;68(8):2587–91]
Data from A Novel Lung Metastasis Signature Links Wnt Signaling with Cancer Cell Self-Renewal and Epithelial-Mesenchymal Transition in Basal-like Breast Cancer
Authors: DiMeo Theresa A. , Anderson Kristen , Phadke Pushkar , Feng Chang , Perou Charles M. , Naber Steven , Kuperwasser Charlotte
Published: March 2024

Abstract
The establishment of metastasis depends on the ability of cancer cells to acquire a migratory phenotype combined with their capacity to recreate a secondary tumor in a distant tissue. In epithelial cancers, such as those of the breast, the epithelial-mesenchymal transition (EMT) is associated with basal-like breast cancers, generates cells with stem-like properties, and enables cancer cell dissemination and metastasis. However, the molecular mechanism(s) that connects stem cell–like characteristics with EMT has yet to be defined. Using an orthotopic model of human breast cancer metastasis to lung, we identified a poor prognosis gene signature, in which several components of the wnt signaling pathway were overexpressed in early lung metastases. The wnt genes identified in this signature were strongly associated with human basal-like breast cancers. We found that inhibiting wnt signaling through LRP6 reduced the capacity of cancer cells to self-renew and seed tumors in vivo. Furthermore, inhibition of wnt signaling resulted in the reexpression of breast epithelial differentiation markers and repression of EMT transcription factors SLUG and TWIST. Collectively, these results provide a molecular link between self-renewal, EMT, and metastasis in basal-like breast cancers. [Cancer Res 2009;69(13):5364–73]
Data from Epigenetic Silencing of the Tumor Suppressor MicroRNA Hsa-miR-124a Regulates CDK6 Expression and Confers a Poor Prognosis in Acute Lymphoblastic Leukemia
Authors: Agirre Xabier , Vilas-Zornoza Amaia , Jiménez-Velasco Antonio , Martin-Subero José Ignacio , Cordeu Lucia , Gárate Leire , San José-Eneriz Edurne , Abizanda Gloria , Rodríguez-Otero Paula , Fortes Puri , Rifón José , Bandrés Eva , Calasanz María José , Martín Vanesa , Heiniger Anabel , Torres Antonio , Siebert Reiner , Román-Gomez José , Prósper Felipe
Published: March 2024

Abstract
Whereas transcriptional silencing of genes due to epigenetic mechanisms is one of the most important alterations in acute lymphoblastic leukemia (ALL), some recent studies indicate that DNA methylation contributes to down-regulation of miRNAs during tumorigenesis. To explore the epigenetic alterations of miRNAs in ALL, we analyzed the methylation and chromatin status of the miR-124a loci in ALL. Expression of miR-124a was down-regulated in ALL by hypermethylation of the promoter and histone modifications including decreased levels of 3mk4H3 and AcH3 and increased levels of 2mK9H3, 3mK9H3, and 3mK27H3. Epigenetic down-regulation of miR-124a induced an up-regulation of its target, CDK6, and phosphorylation of retinoblastoma (Rb) and contributed to the abnormal proliferation of ALL cells both in vitro and in vivo. Cyclin-dependent kinase 6 (CDK6) inhibition by sodium butyrate or PD-0332991 decreased ALL cell growth in vitro, whereas overexpression of pre-miR124a led to decreased tumorigenicity in a xenogeneic in vivo Rag2−/−γc−/− mouse model. The clinical implications of these findings were analyzed in a group of 353 patients diagnosed with ALL. Methylation of hsa-miR-124a was observed in 59% of the patients, which correlated with down-regulation of miR-124a (P < 0.001). Furthermore, hypermethylation of hsa-miR-124a was associated with higher relapse rate (P = 0.001) and mortality rate (P < 0.001), being an independent prognostic factor for disease-free survival (P < 0.001) and overall survival (P = 0.005) in the multivariate analysis. These results provide the grounds for new therapeutic strategies in ALL either targeting the epigenetic regulation of microRNAs and/or directly targeting the CDK6-Rb pathway. [Cancer Res 2009;69(10):4443–53]