bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from BGC 945, a Novel Tumor-Selective Thymidylate Synthase Inhibitor Targeted to α-Folate Receptor–Overexpressing Tumors
Authors: Gibbs David D. , Theti Davinder S. , Wood Nadya , Green Matthew , Raynaud Florence , Valenti Melanie , Forster Martin D. , Mitchell Fraser , Bavetsias Vassilios , Henderson Elisa , Jackman Ann L.
Published: March 2023

Abstract
BGC 945 is a cyclopenta[g]quinazoline–based, thymidylate synthase inhibitor specifically transported into α-folate receptor (α-FR)–overexpressing tumors. Affinity of BGC 945 for the α-FR is 70% of the high-affinity ligand folic acid. In contrast to conventional antifolates, BGC 945 has low affinity for the widely expressed reduced-folate carrier (RFC). The Ki for isolated thymidylate synthase is 1.2 nmol/L and the IC50 for inhibition of the growth of α-FR-negative mouse L1210 or human A431 cells is ∼7 μmol/L. In contrast, BGC 945 is highly potent in a range of α-FR-overexpressing human tumor cell lines (IC50 ∼1-300 nmol/L). Pharmacokinetic variables measured following i.v. injection of 100 mg/kg BGC 945 to KB tumor–bearing mice showed rapid plasma clearance (0.021 L/h) and tissue distribution. The terminal half-lives in plasma, liver, kidney, spleen, and tumor were 2, 0.6, 5, 21, and 28 hours, respectively. Tumor BGC 945 concentration at 24 hours was ∼1 nmol/g tissue, at least 10-fold higher than that in plasma or normal tissues. Inhibition of thymidylate synthase in tissues leads to increased incorporation of 5-[125I]-iodo-2′-deoxyuridine ([125I]dUrd) into DNA. Forty-eight hours after injection of 100 mg/kg 6RS-BGC 945 ([125I]dUrd injected at 24 hours), tumor was the only tissue with incorporation above control level (6-fold). The RFC-mediated thymidylate synthase inhibitor plevitrexed also increased uptake of [125I]dUrd in tumor (10-fold) but, in contrast, also caused increased incorporation in other normal tissues such as spleen and small bowel (4.5- and 4.6-fold, respectively). These data suggest that BGC 945 selectively inhibits thymidylate synthase in α-FR-overexpressing tumors and should cause minimal toxicity to humans at therapeutic doses. (Cancer Res 2005; 65(24): 11721-8)
Data from The PTEN/Akt Pathway Dictates the Direct αVβ3-Dependent Growth-Inhibitory Action of an Active Fragment of Tumstatin in Glioma Cells In vitro and In vivo
Authors: Kawaguchi Tomohiro , Yamashita Yoji , Kanamori Masayuki , Endersby Raelene , Bankiewicz Krystof S. , Baker Suzanne J. , Bergers Gabriele , Pieper Russell O.
Published: March 2023

Abstract
The collagen type IV cleavage fragment tumstatin and its active subfragments bind to integrin αVβ3 and inhibit activation of focal adhesion kinase, phophoinositol-3 kinase, Akt, and mammalian target of rapamycin (mTOR) in what is thought to be an endothelial cell–specific manner. The resultant endothelial cell apoptosis accounts for the ability of tumstatin to function as an endogenous inhibitor of angiogenesis and an indirect suppressor of tumor growth. We hypothesized that the inability of tumstatin to directly suppress tumor cell growth might be the result of the constitutive activation of the Akt/mTOR pathway commonly seen in tumors. Consistent with this idea, several integrin αVβ3–expressing glioma cell lines with PTEN mutations and high levels of phospho-Akt (pAkt) were unaffected by exposure to an active fragment of tumstatin (T3), whereas αVβ3-expressing glioma cell lines with a functional PTEN/low levels of pAkt exhibited T3-induced growth suppression that could be bypassed by small interfering RNA–mediated suppression of PTEN, introduction of a constitutively expressed Akt, or introduction of the Akt and mTOR target eukaryotic translation initiation factor 4E. The direct tumor-suppressive actions of T3 were further shown in an αVβ3-deficient in vivo mouse model in which T3, while unable to alter the tumstatin-insensitive vasculature contributed by the αVβ3-deficient host, nonetheless suppressed the growth and proliferative index of i.c. implanted αVβ3-expressing PTEN-proficient glioma cells. These results show that tumstatin, previously considered to be only an endogenous inhibitor of angiogenesis, also directly inhibits the growth of tumors in a manner dependent on Akt/mTOR activation. (Cancer Res 2006; 66(23): 11331-40)
Data from Two-Dimensional Transcriptome Profiling: Identification of Messenger RNA Isoform Signatures in Prostate Cancer from Archived Paraffin-Embedded Cancer Specimens
Authors: Li Hai-Ri , Wang-Rodriguez Jessica , Nair T. Murlidharan , Yeakley Joanne M. , Kwon Young-Soo , Bibikova Marina , Zheng Christina , Zhou Lixin , Zhang Kui , Downs Tracy , Fu Xiang-Dong , Fan Jian-Bing
Published: March 2023

Abstract
The expression of specific mRNA isoforms may uniquely reflect the biological state of a cell because it reflects the integrated outcome of both transcriptional and posttranscriptional regulation. In this study, we constructed a splicing array to examine ∼1,500 mRNA isoforms from a panel of genes previously implicated in prostate cancer and identified a large number of cell type–specific mRNA isoforms. We also developed a novel “two-dimensional” profiling strategy to simultaneously quantify changes in splicing and transcript abundance; the results revealed extensive covariation between transcription and splicing in prostate cancer cells. Taking advantage of the ability of our technology to analyze RNA from formalin-fixed, paraffin-embedded tissues, we derived a specific set of mRNA isoform biomarkers for prostate cancer using independent panels of tissue samples for feature selection and cross-analysis. A number of cancer-specific splicing switch events were further validated by laser capture microdissection. Quantitative changes in transcription/RNA stability and qualitative differences in splicing ratio may thus be combined to characterize tumorigenic programs and signature mRNA isoforms may serve as unique biomarkers for tumor diagnosis and prognosis. (Cancer Res 2006; 66(8): 4079-88)
Data from Identification of Domains of BRCA1 Critical for the Ubiquitin-Dependent Inhibition of Centrosome Function
Authors: Sankaran Satish , Starita Lea M. , Simons Amanda M. , Parvin Jeffrey D.
Published: March 2023

Abstract
The breast and ovarian cancer specific tumor suppressor BRCA1, bound to BARD1, has multiple functions aimed at maintaining genomic stability in the cell. We have shown earlier that the BRCA1/BARD1 E3 ubiquitin ligase activity regulates centrosome-dependent microtubule nucleation. In this study, we tested which domains of BRCA1 and BARD1 were required to control the centrosome function. In the present study, (a) we confirmed that the ubiquitination activity of BRCA1 regulates centrosome number and function in Hs578T breast cancer cells; (b) we observed that both the amino and carboxyl termini of BRCA1 are required for regulation of centrosome function in vitro; (c) an internal domain (770-1,290) is dispensable for centrosome regulation; (d) BARD1 is required for regulation of centrosome function and protein sequences within the terminal 485 amino acids are necessary for activity; and (e) BARD1 is localized at the centrosome throughout the cell cycle. We conclude that the BRCA1-dependent E3 ubiquitin ligase functions to restrain centrosomes in mammary cells, and loss of BRCA1 in the precancerous breast cell leads to centrosomal hypertrophy, a phenotype commonly observed in incipient breast cancer. (Cancer Res 2006; 66(8): 4100-7)
Data from Immunization of Stage IV Melanoma Patients with Melan-A/MART-1 and gp100 Peptides plus IFN-α Results in the Activation of Specific CD8+ T Cells and Monocyte/Dendritic Cell Precursors
Authors: Di Pucchio Tiziana , Pilla Lorenzo , Capone Imerio , Ferrantini Maria , Montefiore Enrica , Urbani Francesca , Patuzzo Roberto , Pennacchioli Elisabetta , Santinami Mario , Cova Agata , Sovena Gloria , Arienti Flavio , Lombardo Claudia , Lombardi Arianna , Caporaso Patrizia , D'Atri Stefania , Marchetti Paolo , Bonmassar Enzo , Parmiani Giorgio , Belardelli Filippo , Rivoltini Licia
Published: March 2023

Abstract
The use of IFN-α in clinical oncology has generally been based on the rationale of exploiting its antiproliferative and antiangiogenic activities. However, IFN-α also exhibits enhancing effects on T-cell and dendritic cell functions, which may suggest a novel use as a vaccine adjuvant. We have carried out a pilot phase I-II trial to determine the effects of IFN-α, administered as an adjuvant of Melan-A/MART-1:26-35(27L) and gp100:209-217(210M) peptides, on immune responses in stage IV melanoma patients. In five of the seven evaluable patients, a consistent enhancement of CD8+ T cells recognizing modified and native MART-1 and gp100 peptides and MART-1+gp100+ melanoma cells was observed. Moreover, vaccination induced an increase in CD8+ T-cell binding to HLA tetramers containing the relevant peptides and an increased frequency of CD45RA+CCR7− (terminally differentiated effectors) and CD45RA−CCR7− (effector memory) cells. In all patients, treatment augmented significantly the percentage of CD14+ monocytes and particularly of the CD14+CD16+ cell fraction. An increased expression of CD40 and CD86 costimulatory molecules in monocytes was also observed. Notably, postvaccination monocytes from two of the three patients showing stable disease or long disease-free survival showed an enhanced antigen-presenting cell function and capability to secrete IP10/CXCL10 when tested in mixed leukocyte reaction assays, associated to a boost of antigen and melanoma-specific CD8+ T cells. Although further clinical studies are needed to show the adjuvant activity of IFN-α, the present data represent an important starting point for considering a new clinical use of IFN-α and new immunologic end points, potentially predictive of clinical response. (Cancer Res 2006; 66(9): 4943-51)
Data from Target Sequence Accessibility Limits Activation-Induced Cytidine Deaminase Activity in Primary Mediastinal B-Cell Lymphoma
Authors: Popov Sergey W. , Moldenhauer Gerhard , Wotschke Beate , Brüderlein Silke , Barth Thomas F. , Dorsch Karola , Ritz Olga , Möller Peter , Leithäuser Frank
Published: March 2023

Abstract
Activation-induced cytidine deaminase (AID) initiates somatic hypermutation (SHM) and class switch recombination (CSR) in activated B lymphocytes and is potentially implicated in genomic instability of B-cell malignancies. For unknown reasons, B-cell neoplasms often lack SHM and CSR in spite of high AID expression. Here, we show that primary mediastinal B-cell lymphoma (PMBL), an immunoglobulin (Ig)–negative lymphoma that possesses hypermutated, class-switched Ig genes, expresses high levels of AID with an intact primary structure but does not do CSR in 14 of 16 cases analyzed. Absence of CSR coincided with low Ig germ-line transcription, whereas high level germ-line transcription was observed only in those two cases with active CSR. Interleukin-4/CD40L costimulation induced CSR and a marked up-regulation of germ-line transcription in the PMBL-derived cell line MedB-1. In the PMBL cell line Karpas 1106P, CSR was not inducible and germ-line transcription remained low on stimulation. However, Karpas 1106P, but not MedB-1, had ongoing SHM of the Ig gene and BCL6. These genes were transcribed in Karpas 1106P, whereas transcription was undetectable or low in MedB-1 cells. Thus, accessibility of the target sequences seems to be a major limiting factor for AID-dependent somatic gene diversification in PMBL. [Cancer Res 2007;67(14):6555–64]
Data from A Novel SV40 TAg Transgenic Model of Asbestos-Induced Mesothelioma: Malignant Transformation Is Dose Dependent
Authors: Robinson Cleo , van Bruggen Ivonne , Segal Amanda , Dunham Melissa , Sherwood Amanda , Koentgen Frank , Robinson Bruce W.S. , Lake Richard A.
Published: March 2023

Abstract
Although it has been clear for >40 years that mesothelioma can be caused by asbestos, not all patients with this disease have a history of asbestos exposure. Other factors, including non-asbestos fibers and ionizing radiation, are known to cause malignant transformation of mesothelial cells. In addition, it is likely that genetics will play some role in susceptibility. Recently, it has been suggested that SV40 viral oncogenes could contribute to the carcinogenicity of asbestos. To better understand the role of SV40, we used the mesothelin promoter to construct MexTAg mice that express SV40 large T antigen (TAg) in the mesothelial compartment. We generated four MexTAg lines that carry high, intermediate, and low copy numbers of the transgene. All of these mice show a relatively low level of spontaneous tumor development. High-copy, 299h mice rapidly developed mesotheliomas when exposed to asbestos, and these tumors were faster growing and more invasive than those developing in wild-type and single-copy (266s) mice. In addition, we found a direct relationship between transgene copy number and survival after exposure to asbestos. A single copy of TAg was sufficient to immortalize mesothelial cells in vitro, but these cells did not show evidence of malignant transformation. In contrast, cell lines developed from mesothelial cells of animals carrying multiple copies of TAg were growth factor independent and could be cloned at limiting dilution in soft agar. These data provide the first in vivo demonstration of co-carcinogenicity between SV40 and asbestos. (Cancer Res 2006; 66(22): 10786-94)
Data from Thiazolidinediones Inhibit Insulin-Like Growth Factor-I–Induced Activation of p70S6 Kinase and Suppress Insulin-Like Growth Factor-I Tumor-Promoting Activity
Authors: He Guobin , Sung You Me , DiGiovanni John , Fischer Susan M.
Published: March 2023

Abstract
Thiazolidinediones are a novel class of antidiabetic drugs that improve insulin sensitivity in type 2 diabetic patients. Recently, these compounds have also been shown to suppress tumor development in several animal models. The molecular basis for their antitumor action, however, is largely unknown. We report here that oral administration of thiazolidinediones (rosiglitazone and troglitazone) remarkably inhibited insulin-like growth factor-I (IGF-I)–promoted skin tumor development by 73% in BK5.IGF-1 transgenic mice, although they were previously found to be ineffective in inhibiting UV- or chemically induced mouse skin tumorigenesis. The anti-IGF-I effect of troglitazone in mouse skin keratinocytes was due to, at least partially, inhibition of IGF-I–induced phosphorylation of p70S6 kinase (p70S6K) at Thr389, a site specifically phosphorylated by mammalian target of rapamycin (mTOR). Troglitazone did not directly inhibit mTOR kinase activity as shown by mTOR in vitro kinase assay but rapidly activated AMP-activated protein kinase (AMPK) through a yet undefined peroxisome proliferator-activated receptor γ–independent mechanism. Expression of a dominant-negative AMPK reversed the inhibitory effect of troglitazone on IGF-I–induced phosphorylation of p70S6K, suggesting that troglitazone inhibited IGF-I and p70S6K signaling through activation of AMPK. Collectively, these data suggest that thiazolidinediones specifically inhibit IGF-I tumor-promoting activity in mouse skin through activation of AMPK and subsequent inhibition of p70S6K. (Cancer Res 2006; 66(3): 1872-8)
Data from Increased Expression of Osteopontin Contributes to the Progression of Prostate Cancer
Authors: Khodavirdi Ani C. , Song Zhigang , Yang Shangxin , Zhong Chen , Wang Shunyou , Wu Hong , Pritchard Colin , Nelson Peter S. , Roy-Burman Pradip
Published: March 2023

Abstract
Osteopontin is a secreted glycosylated phosphoprotein known to be involved in numerous physiologic functions and associated with the late stages of various cancers. We used preneoplastic and neoplastic mouse models of prostate cancer to determine the onset of elevated expression of osteopontin in the development of this disease. Osteopontin alterations occurred early in the disease with dysregulated expression observed in lesions of low-grade prostatic intraepithelial neoplasia (PIN). Over time, osteopontin expressing dysplastic cells seemed to increase in number in high-grade PIN and increased further in adenocarcinoma, and in metastasis, almost all of the cancer cells immunohistochemically stained positive for osteopontin overexpression. We examined the biological properties of human prostate cancer cell lines LNCaP and PC-3, in which osteopontin overexpression was achieved via lentiviral gene transduction. Evidence was obtained that osteopontin could contribute to a proliferative advantage in both cell types, although more significantly in LNCaP than PC-3. Osteopontin also influenced their in vitro invasive ability, and again, most strikingly in the weakly oncogenic LNCaP. Furthermore, excess osteopontin induced the LNCaP cells to acquire a strong intravasation potential in vivo in the chicken embryo chorioallantoic membrane assay for blood vessel penetration. These results establish a correlation between an increased gradient of osteopontin expression throughout the stages of murine prostate cancer, beginning from the preneoplastic lesions to distant metastases that suggests a proliferative and invasive advantages to those prostate tumor cells overexpressing osteopontin. Together, these findings support a strategy designed to target osteopontin in the context of prostate cancer therapy. (Cancer Res 2006; 66(2): 883-8)
Data from Soluble IGF2 Receptor Rescues ApcMin/+ Intestinal Adenoma Progression Induced by Igf2 Loss of Imprinting
Authors: Harper James , Burns Jason L. , Foulstone Emily J. , Pignatelli Massimo , Zaina Silvio , Hassan A. Bassim
Published: March 2023

Abstract
The potent growth-promoting activity of insulin-like growth factor-II (IGF-II) is highly regulated during development but frequently up-regulated in tumors. Increased expression of the normally monoallelic (paternally expressed) mouse (Igf2) and human (IGF2) genes modify progression of intestinal adenoma in the ApcMin/+ mouse and correlate with a high relative risk of human colorectal cancer susceptibility, respectively. We examined the functional consequence of Igf2 allelic dosage (null, monoallelic, and biallelic) on intestinal adenoma development in the ApcMin/+ by breeding with mice with either disruption of Igf2 paternal allele or H19 maternal allele and used these models to evaluate an IGF-II–specific therapeutic intervention. Increased allelic Igf2 expression led to elongation of intestinal crypts, increased adenoma growth independent of systemic growth, and increased adenoma nuclear β-catenin staining. By introducing a transgene expressing a soluble form of the full-length IGF-II/mannose 6-phosphate receptor (sIGF2R) in the intestine, which acts as a specific inhibitor of IGF-II ligand bioavailability (ligand trap), we show rescue of the Igf2-dependent intestinal and adenoma phenotype. This evidence shows the functional potency of allelic dosage of an epigenetically regulated gene in cancer and supports the application of an IGF-II ligand–specific therapeutic intervention in colorectal cancer. (Cancer Res 2006; 66(4): 1940-8)
Data from Sphingosine-Induced Apoptosis in Rhabdomyosarcoma Cell Lines Is Dependent on Pre-Mitochondrial Bax Activation and Post-Mitochondrial Caspases
Authors: Phillips Darren C. , Martin Sophie , Doyle Belinda T. , Houghton Janet A.
Published: March 2023

Abstract
Sphingolipids is the collective term ascribed to components of the sphingomyelin cycle. Modulation of the cellular levels of individual sphingolipids can induce a diverse range of cellular responses including apoptosis, proliferation, and cell cycle arrest. We present data showing that rhabdomyosarcoma cell lines, independent of lineage (alveolar rhabdomyosarcoma and embryonal rhabdomyosarcoma), are particularly sensitive to the induction of apoptosis as a result of an elevation in the cellular levels of sphingosine (d-erythro-sphingosine). Sphingosine-mediated apoptosis does not require its metabolism to the related proapoptotic molecule ceramide and is stereospecific because exposure of the rhabdomyosarcoma cell line RD to the l-erythro and dl-threo isoforms of sphingosine did not induce apoptosis. Importantly, for efficient induction of apoptosis, sphingosine required Bax activation and consequential translocation to the mitochondria. This resulted in selective mitochondrial release of cytochrome c and Smac/Diablo but not other mitochondrial related factors (apoptosis-inducing factor, endonuclease G, and HtrA2/Omi). Using small interfering RNA, reduced Bax expression conferred the impaired release of mitochondrial cytochrome c to the cytoplasm following sphingosine exposure, inhibiting the induction of apoptosis. Furthermore, dissipation of the inner mitochondrial membrane potential and enhanced production of reactive oxygen species were not observed. Bax activation and cytochrome c release were independent of caspases; however, caspase-3 and caspase-9 activity distal to the mitochondria was essential for the execution of apoptosis. [Cancer Res 2007;67(2):756–64]
Data from Growth Properties of Colonic Tumor Cells Are a Function of the Intrinsic Mitochondrial Membrane Potential
Authors: Heerdt Barbara G. , Houston Michele A. , Augenlicht Leonard H.
Published: March 2023

Abstract
Development of malignant transformation in the colonic mucosa includes disruption in the equilibrium between proliferation and apoptosis, decreased expression and deletions of the mitochondrial genome, alterations in mitochondrial enzymatic activity, and elevations in the mitochondrial membrane potential (Δψm). Focusing on the role of the Δψm in tumor development and progression, we generated novel isogenic colonic carcinoma cell lines that exhibit highly significant, stable differences in their intrinsic Δψm. Using these cell lines, we have recently shown that the intrinsic Δψm has a significant influence on steady state mitochondrial activity and the extent to which cells enter butyrate-mediated growth arrest and apoptotic cascades. Here, we report that the Δψm is also profoundly linked to important tumorigenic properties of the cells. Compared with cells with lower Δψm, cells with elevated intrinsic Δψm have an enhanced capacity to (a) respond to hypoxia by avoiding apoptosis and initiating angiogenesis, (b) escape anoikis and grow under anchorage-independent conditions, and (c) invade the basement membrane. Combined with our previous work, these data implicate the intrinsic Δψm of colonic carcinoma cells in determining the probability of tumor expansion and progression. (Cancer Res 2006; 66(3): 1591-6)
Data from Adoptively Transferred Tumor-Specific T Cells Stimulated Ex vivo Using Herpes Simplex Virus Amplicons Encoding 4-1BBL Persist in the Host and Show Antitumor Activity In vivo
Authors: Yi Kyung H. , Nechushtan Hovav , Bowers William J. , Walker Gail R. , Zhang Yu , Pham Dien G. , Podack Eckhard R. , Federoff Howard J. , Tolba Khaled A. , Rosenblatt Joseph D.
Published: March 2023

Abstract
4-1BB is a T-cell costimulatory receptor which binds its ligand 4-1BBL, resulting in prolonged T cell survival. We studied the antitumor effects of adoptively transferred tumor-specific T cells expanded ex vivo using tumors transduced with herpes simplex virus (HSV) amplicons expressing 4-1BBL as a direct source of antigen and costimulation. We constructed HSV amplicons encoding either the 4-1BBL (HSV.4-1BBL) or B7.1 (HSV.B7.1) costimulatory ligands. Lewis lung carcinoma cells expressing ovalbumin (LLC/OVA) were transduced with HSV.4-1BBL, HSV.B7.1, or control HSV amplicons and used to stimulate GFP+ OVA-specific CD8+ T cells (OT-1/GFP) ex vivo. Naive or ex vivo stimulated OT-1/GFP cells were adoptively transferred into LLC/OVA tumor-bearing mice. Higher percentages of OT-1/GFP cells were seen in the peripheral blood, spleen, and tumor bed of the HSV.4-1BBL–stimulated OT-1/GFP group compared with all other experimental groups. OT-1 cells identified within the tumor bed and draining lymph nodes of the HSV.4-1BBL–stimulated OT-1 group showed enhanced bromodeoxyuridine (BrdUrd) incorporation, suggesting ongoing expansion in vivo. Mice receiving HSV.4-1BBL–stimulated OT-1/GFP had significantly decreased tumor volumes compared with untreated mice (P < 0.001) or to mice receiving naive OT-1/GFP (P < 0.001). Transfer of HSV.B7.1-stimulated OT-1/GFP did not protect mice from tumor. Mice that received HSV.4-1BBL–stimulated OT-1/GFP exhibited increased cytolytic activity against LLC/OVA and higher percentages of Ly-6C+ OT-1/GFP in the spleen and tumor bed compared with controls. Tumor-specific T cells stimulated ex vivo using tumor transduced with HSV.4-1BBL expand in vivo following adoptive transfer, resulting in tumor eradication and the generation of tumor-specific CD44+Ly-6C+CD62L− effector memory T cells. [Cancer Res 2007;67(20):10027–37]
Data from Thrombospondin-1 Peptide ABT-510 Combined with Valproic Acid Is an Effective Antiangiogenesis Strategy in Neuroblastoma
Authors: Yang Qiwei , Tian Yufeng , Liu Shuqing , Zeine Rana , Chlenski Alexandre , Salwen Helen R. , Henkin Jack , Cohn Susan L.
Published: March 2023

Abstract
In the pediatric cancer neuroblastoma, clinically aggressive disease is associated with increased levels of angiogenesis stimulators and high vascular index. We and others have hypothesized that blocking angiogenesis may be effective treatment for this pediatric malignancy. However, little is known about the efficacy of antiangiogenic agents in pediatric malignancies. Recently, promising results have been reported in an adult phase I study of ABT-510, a peptide derivative of the natural angiogenic inhibitor thrombospondin-1. Histone deacetylase inhibitors, such as valproic acid (VPA), have also been shown to have antiangiogenic activity in several cancer models. In this study, we evaluated the effects of ABT-510 and VPA on neuroblastoma tumor growth and angiogenesis. Although only VPA was capable of blocking the proliferation of neuroblastoma cells and inducing neuroblastoma cell apoptosis in vitro, treatment with VPA or ABT-510 alone significantly suppressed the growth of neuroblastoma xenografts established from two different MYCN-amplified cell lines. Combination therapy more effectively inhibited the growth of small neuroblastoma xenografts than single-agent treatment, and in animals with large xenografts, total cessation of tumor growth was achieved with this treatment approach. The microvascular density was significantly reduced in the xenografts treated with combination therapy compared with controls or tumors treated with single agents. In addition, the number of structurally abnormal vessels was reduced, suggesting that these agents may “normalize” the tumor vasculature. Our results indicate that ABT-510 combined with VPA may be an effective antiangiogenic treatment strategy for children with high-risk neuroblastoma. [Cancer Res 2007;67(4):1716–24]
Data from Extensive Methylation Is Associated with β-Catenin Mutations in Hepatocellular Carcinoma: Evidence for Two Distinct Pathways of Human Hepatocarcinogenesis
Authors: Nishida Naoshi , Nishimura Takafumi , Nagasaka Takeshi , Ikai Iwao , Ajay Goel , Boland C. Richard
Published: March 2023

Abstract
Hepatocellular carcinoma (HCC) with p53 mutations is usually characterized by extensive chromosomal instability (CIN), whereas those with β-catenin mutations have relatively less CIN and the molecular pathogenesis of these tumors is unknown. Methylation of CpG dinucleotides in the promoters of cancer-related genes is another characteristic feature of HCCs. The aim of this study was to determine the contribution of the methylator phenotype to HCC and its relationship to genomic instability. Fractional allelic loss (FAL) was determined using 400 microsatellite markers in 81 HCCs and 77 corresponding noncancerous livers as a measure of CIN. Methylation of 21 genetic loci was quantitated using combined bisulfite restriction analysis. Using hierarchical clustering analysis based upon the quantification of methylation levels, all HCCs were segregated into two groups characterized by either limited or extensive methylation. Mutations in the β-catenin and p53 genes were determined by DNA sequencing. We found that the methylation levels were significantly higher in the HCCs than in noncancerous livers in 18 of the 21 loci (P values ranged from 0.035 to <0.0001). Among 18 loci, elevated levels of methylation at nine loci were significantly associated with β-catenin mutations (P values ranged from 0.02 to <0.0001). In addition, the presence of β-catenin mutations was associated with HCCs in the extensive methylation group (P < 0.0001), whereas p53 mutations correlated with high FAL scores (P = 0.0036). These data suggest that HCCs can be classified into two distinct categories based upon promoter methylation, CIN, and mutations of cancer-related genes. HCCs with extensive methylation harbor frequent β-catenin mutations, whereas HCCs with high levels of CIN are associated with p53 mutations, suggesting the presence of two independent pathways for the pathogenesis of HCC. [Cancer Res 2007;67(10):4586–94]
Data from Selective Inhibition of ErbB2-Overexpressing Breast Cancer In vivo by a Novel TAT-Based ErbB2-Targeting Signal Transducers and Activators of Transcription 3–Blocking Peptide
Authors: Tan Ming , Lan Keng-Hsueh , Yao Jun , Lu Chien-Hsing , Sun Menghong , Neal Christopher L. , Lu Jing , Yu Dihua
Published: March 2023

Abstract
ErbB2 is an excellent target for cancer therapies. Unfortunately, the outcome of current therapies for ErbB2-positive breast cancers remains unsatisfying due to resistance and side effects. New therapies for ErbB2-overexpressing breast cancers continue to be in great need. Peptide therapy using cell-penetrating peptides (CPP) as peptide carriers is promising because the internalization is highly efficient, and the cargoes delivered can be bioactive. However, the major obstacle in using these powerful CPPs for therapy is their lack of specificity. Here, we sought to develop a peptide carrier that could introduce therapeutics specifically to ErbB2-overexpressing breast cancer cells. By modifying the HIV TAT-derived CPP and conjugating anti-HER-2/neu peptide mimetic (AHNP), we developed the peptide carrier (P3-AHNP) that specifically targeted ErbB2-overexpressing breast cancer cells in vitro and in vivo. A signal transducers and activators of transcription 3 (STAT3)–inhibiting peptide conjugated to this peptide carrier (P3-AHNP-STAT3BP) was delivered more efficiently into ErbB2-overexpressing than ErbB2 low-expressing cancer cells in vitro and successfully decreased STAT3 binding to STAT3-interacting DNA sequence. P3-AHNP-STAT3BP inhibited cell growth in vitro, with ErbB2-overexpressing 435.eB breast cancer cells being more sensitive to the treatment than the ErbB2 low-expressing MDA-MB-435 cells. Compared with ErbB2 low-expressing MDA-MB-435 xenografts, i.p. injected P3-AHNP-STAT3BP preferentially accumulated in 435.eB xenografts, which led to more reduction of proliferation and increased apoptosis and targeted inhibition of tumor growth. This novel peptide delivery system provided a sound basis for the future development of safe and effective new-generation therapeutics to cancer-specific molecular targets. (Cancer Res 2006; 66(7): 3764-72)
Data from Lack of Extracellular Signal-Regulated Kinase Mitogen-Activated Protein Kinase Signaling Shows a New Type of Melanoma
Authors: Shields Janiel M. , Thomas Nancy E. , Cregger Melissa , Berger Aaron J. , Leslie Michael , Torrice Chad , Hao Honglin , Penland Shannon , Arbiser Jack , Scott Glynis , Zhou Tong , Bar-Eli Menashe , Bear James E. , Der Channing J. , Kaufmann William K. , Rimm David L. , Sharpless Norman E.
Published: March 2023

Abstract
The majority of human melanomas harbor activating mutations of either N-RAS or its downstream effector B-RAF, which cause activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase and the ERK MAPK cascade. The melanoma-relevant effectors of ERK activation, however, are largely unknown. In this work, we show that increased ERK activation correlates strongly with mutational status of N-RAS or B-RAF in 21 melanoma cell lines. Melanoma lines that were wild-type for RAS/RAF showed low levels of ERK activation comparable with primary human melanocytes. Through supervised analysis of RNA expression profiles, we identified 82 genes, including TWIST1, HIF1α, and IL-8, which correlated with ERK activation across the panel of cell lines and which decreased with pharmacologic inhibition of ERK activity, suggesting that they are ERK transcriptional targets in melanoma. Additionally, lines lacking mutations of N-RAS and B-RAF were molecularly distinct and characterized by p53 inactivation, reduced ERK activity, and increased expression of epithelial markers. Analysis of primary human melanomas by tissue microarray confirmed a high correlation among expression of these epithelial markers in a heterogeneous sample of 570 primary human tumors, suggesting that a significant frequency of primary melanomas is of this “epithelial-like” subtype. These results show a molecularly distinct melanoma subtype that does not require ERK activation or epithelial-mesenchymal transformation for progression. [Cancer Res 2007;67(4):1502–12]
Data from Sulforaphane Sensitizes Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand (TRAIL)–Resistant Hepatoma Cells to TRAIL-Induced Apoptosis through Reactive Oxygen Species–Mediated Up-regulation of DR5
Authors: Kim Heesue , Kim Eun Hee , Eom Young Woo , Kim Wook-Hwan , Kwon Taeg Kyu , Lee Soo Jae , Choi Kyeong Sook
Published: March 2023

Abstract
Sulforaphane is a chemopreventive agent present in various cruciferous vegetables, including broccoli. Here, we show that treatment with tumor necrosis factor (TNF)–related apoptosis-inducing ligand (TRAIL) in combination with subtoxic doses of sulforaphane significantly induces rapid apoptosis in TRAIL-resistant hepatoma cells. Neither TNF-α- nor Fas-mediated apoptosis was sensitized in hepatoma cells by cotreatment with sulforaphane, suggesting that sulforaphane can selectively sensitize cells to TRAIL-induced apoptosis but not to apoptosis mediated by other death receptors. We found that sulforaphane treatment significantly up-regulated mRNA and protein levels of DR5, a death receptor of TRAIL. This was accompanied by an increase in the generation of reactive oxygen species (ROS). Pretreatment with N-acetyl-l-cysteine and overexpression of catalase inhibited sulforaphane-induced up-regulation of DR5 and almost completely blocked the cotreatment-induced apoptosis. Furthermore, the sulforaphane-mediated sensitization to TRAIL was efficiently reduced by administration of a blocking antibody or small interfering RNAs for DR5. These results collectively indicate that sulforaphane-induced generation of ROS and the subsequent up-regulation of DR5 are critical for triggering and amplifying TRAIL-induced apoptotic signaling. We also found that sulforaphane can sensitize both Bcl-xL- and Bcl-2-overexpressing hepatoma cells to TRAIL-induced apoptosis, indicating that treatment with a combination of TRAIL and sulforaphane may be a safe strategy for treating resistant hepatomas. (Cancer Res 2006; 66(3): 1740-50)
Data from Targeted Cancer Gene Therapy Using a Hypoxia Inducible Factor–Dependent Oncolytic Adenovirus Armed with Interleukin-4
Authors: Post Dawn E. , Sandberg Eric M. , Kyle Michele M. , Devi Narra Sarojini , Brat Daniel J. , Xu Zhiheng , Tighiouart Mourad , Van Meir Erwin G.
Published: March 2023

Abstract
There is a need for novel therapies targeting hypoxic cells in tumors. These cells are associated with tumor resistance to therapy and express hypoxia inducible factor-1 (HIF-1), a transcription factor that mediates metabolic adaptation to hypoxia and activates tumor angiogenesis. We previously developed an oncolytic adenovirus (HYPR-Ad) for the specific killing of hypoxic/HIF-active tumor cells, which we now armed with an interleukin-4 gene (HYPR-Ad-IL4). We designed HYPR-Ad-IL4 by cloning the Ad E1A viral replication and IL-4 genes under the regulation of a bidirectional hypoxia/HIF-responsive promoter. The IL-4 cytokine was chosen for its ability to induce a strong host antitumor immune response and its potential antiangiogenic activity. HYPR-Ad-IL4 induced hypoxia-dependent IL-4 expression, viral replication, and conditional cytolysis of hypoxic, but not normoxic cells. The treatment of established human tumor xenografts with HYPR-Ad-IL4 resulted in rapid and maintained tumor regression with the same potency as that of wild-type dl309-Ad. HYPR-Ad-IL4–treated tumors displayed extensive necrosis, fibrosis, and widespread viral replication. Additionally, these tumors contained a distinctive leukocyte infiltrate and prominent hypoxia. The use of an oncolytic Ad that locally delivers IL-4 to tumors is novel, and we expect that HYPR-Ad-IL4 will have broad therapeutic use for all solid tumors that have hypoxia or active HIF, regardless of tissue origin or genetic alterations. [Cancer Res 2007;67(14):6872–81]
Data from Low Surface Expression of B7-1 (CD80) Is an Immunoescape Mechanism of Colon Carcinoma
Authors: Tirapu Iñigo , Huarte Eduardo , Guiducci Cristiana , Arina Ainhoa , Zaratiegui Mikel , Murillo Oihana , Gonzalez Alvaro , Berasain Carmen , Berraondo Pedro , Fortes Puri , Prieto Jesús , Colombo Mario P. , Chen Lieping , Melero Ignacio
Published: March 2023

Abstract
Artificially enforced expression of CD80 (B7-1) and CD86 (B7-2) on tumor cells renders them more immunogenic by triggering the CD28 receptor on T cells. The enigma is that such B7s interact with much higher affinity with CTLA-4 (CD152), an inhibitory receptor expressed by activated T cells. We show that unmutated CD80 is spontaneously expressed at low levels by mouse colon carcinoma cell lines and other transplantable tumor cell lines of various tissue origins. Silencing of CD80 by interfering RNA led to loss of tumorigenicity of CT26 colon carcinoma in immunocompetent mice, but not in immunodeficient Rag−/− mice. CT26 tumor cells bind CTLA-4Ig, but much more faintly with a similar CD28Ig chimeric protein, thus providing an explanation for the dominant inhibitory effects on tumor immunity displayed by CD80 at that expression level. Interestingly, CD80-negative tumor cell lines such as MC38 colon carcinoma and B16 melanoma express CD80 at dim levels during in vivo growth in syngeneic mice. Therefore, low CD80 surface expression seems to give an advantage to cancer cells against the immune system. Our findings are similar with the inhibitory role described for the dim CD80 expression on immature dendritic cells, providing an explanation for the low levels of CD80 expression described in various human malignancies. (Cancer Res 2006; 66(4): 2442-50)
Data from Nongenotoxic p53 Activation Protects Cells against S-Phase–Specific Chemotherapy
Authors: Kranz Dominique , Dobbelstein Matthias
Published: March 2023

Abstract
Mutations in the tumor suppressor gene TP53 represent the most frequent genetic difference between tumor cells and normal cells. Here, we have attempted to turn this difference into an advantage for normal cells during therapy. Using the Mdm2 antagonist nutlin-3, we first activated p53 in U2OS and HCT116 cells to induce cell cycle arrest. These arrested cells were found to be resistant to subsequent transient treatment with the nucleoside analogue gemcitabine, as revealed by clonogenic assays following drug removal. In contrast, isogenic cells lacking functional p53 continued to enter S phase regardless of nutlin-3 pretreatment and remained highly susceptible to gemcitabine-mediated cytotoxicity. The sequential treatment with nutlin-3 alone, followed by transient exposure to nutlin-3 plus gemcitabine, efficiently compromised the clonogenicity of tumor cells with deletions or mutations of p53 but largely spared the proliferation of nontransformed human keratinocytes. Nutlin-3 pretreatment also conferred protection of p53-proficient cells against cytosine arabinoside but not against doxorubicin or cisplatin. We propose that the cell cycle arrest function of p53 can be used to convert p53 from a killer to a protector of cells, with the potential to reduce unwanted side effects of chemotherapy. (Cancer Res 2006; 66(21): 10274-80)
Data from Prediction of Sensitivity of Rectal Cancer Cells in Response to Preoperative Radiotherapy by DNA Microarray Analysis of Gene Expression Profiles
Authors: Watanabe Toshiaki , Komuro Yasuhiro , Kiyomatsu Tomomichi , Kanazawa Takamitsu , Kazama Yoshihiro , Tanaka Junichiro , Tanaka Toshiaki , Yamamoto Yoko , Shirane Masatoshi , Muto Tetsuichiro , Nagawa Hirokazu
Published: March 2023

Abstract
Preoperative radiotherapy has been widely used to improve local control of disease and to improve survival in the treatment of rectal cancer. However, the response to radiotherapy differs among individual tumors. Our objective here was to identify a set of discriminating genes that can be used for characterization and prediction of response to radiotherapy in rectal cancer. Fifty-two rectal cancer patients who underwent preoperative radiotherapy were studied. Biopsy specimens were obtained from rectal cancer before preoperative radiotherapy. Response to radiotherapy was determined by histopathologic examination of surgically resected specimens and classified as responders or nonresponders. By determining gene expression profiles using human U95Av2 Gene Chip, we identified 33 novel discriminating genes of which the expression differed significantly between responders and nonresponders. Using this gene set, we were able to establish a new model to predict response to radiotherapy in rectal cancer with an accuracy of 82.4%. The list of discriminating genes included growth factor, apoptosis, cell proliferation, signal transduction, or cell adhesion–related genes. Among 33 discriminating genes, apoptosis inducers (lumican, thrombospondin 2, and galectin-1) showed higher expression in responders whereas apoptosis inhibitors (cyclophilin 40 and glutathione peroxidase) showed higher expression in nonresponders. The present study suggested the possibility that gene expression profiling may be useful in predicting response to radiotherapy to establish an individualized tailored therapy for rectal cancer. Global expression profiles of responders and nonresponders may provide insights into the development of novel therapeutic targets. (Cancer Res 2006; 66(7): 3370-4)
Data from Endothelin-1 and Endothelin-3 Promote Invasive Behavior via Hypoxia-Inducible Factor-1α in Human Melanoma Cells
Authors: Spinella Francesca , Rosanò Laura , Di Castro Valeriana , Decandia Samantha , Nicotra Maria Rita , Natali Pier Giorgio , Bagnato Anna
Published: March 2023

Abstract
Endothelin (ET) B receptor (ETBR), which is overexpressed in human cutaneous melanomas, promotes tumorigenesis upon activation by ET-1 or ET-3, thus representing a potential novel therapeutic target. Hypoxia-inducible factor-1α (HIF-1α) is the transcriptional factor that conveys signaling elicited by hypoxia and growth factor receptors. Here, we investigated the interplay between ET axis and hypoxia in primary and metastatic melanoma cell lines. We report that under normoxic conditions, ETBR activation by ET-1/ET-3 enhances vascular endothelial growth factor (VEGF) up-regulation, cyclooxygenase (COX)-1/COX-2 protein expression and COX-2 promoter activity, prostaglandin E2 (PGE2) production, and do so to a greater extent under hypoxia. Moreover, COX-1/COX-2 inhibitors block ET-induced PGE2 and VEGF secretion, matrix metalloproteinase (MMP) activation, and cell invasion, indicating that both enzymes function as downstream mediators of ET-induced invasive properties. The ETBR selective antagonist BQ788 or transfection with ETBR small interfering RNA (siRNA) block the ET-mediated effects. ETs also increase HIF-1α expression under both normoxic and hypoxic conditions and its silencing by siRNA desensitizes COX-2 transcriptional activity, PGE2 and VEGF production, and MMP activation in response to ET-3, implicating, for the first time, HIF-1α/COX as downstream targets of ETBR signaling leading to invasiveness. In melanoma xenografts, specific ETBR antagonist suppresses tumor growth, neovascularization, and invasiveness-related factors. Collectively, these results identify a new mechanism whereby ET-1/ET-3/ETBR axis can promote and interact with the HIF-1α–dependent machinery to amplify the COX-mediated invasive behavior of melanoma. New therapeutic strategies using specific ETBR antagonist could provide an improved approach to the treatment of melanoma by inhibiting tumor growth and progression. [Cancer Res 2007;67(4):1725–34]
Data from Dominant-Negative Activator Protein 1 (TAM67) Targets Cyclooxygenase-2 and Osteopontin under Conditions in which It Specifically Inhibits Tumorigenesis
Authors: Matthews Connie P. , Birkholz Alysia M. , Baker Alyson R. , Perella Christine M. , Beck George R. , Young Matthew R. , Colburn Nancy H.
Published: March 2023

Abstract
Activation of activator protein 1 (AP-1) and nuclear factor κB (NFκB)–dependent transcription is required for tumor promotion in cell culture models and transgenic mice. Dominant-negative c-Jun (TAM67) blocks AP-1 activation by dimerizing with Jun or Fos family proteins and blocks NFκB activation by interacting with NFκB p65. Two-stage [7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA)] skin carcinogenesis experiments in a model relevant to human cancer risk, transgenic mice expressing human papillomavirus 16 E7 oncogene (K14-HPV16-E7), show E7-enhanced tumor promotion. A cross to K14-TAM67–expressing mice results in dramatic inhibition of tumor promoter–induced AP-1 luciferase reporter activation and papillomagenesis. Epithelial specific TAM67 expression inhibits tumorigenesis without affecting TPA- or E7-induced hyperproliferation of the skin. Thus, the mouse model enriches for TAM67 targets relevant to tumorigenesis rather than to general cell proliferation or hyperplasia, implicating a subset of AP-1– and/or NFκB-dependent genes. The aim of the present study was to identify target genes responsible for TAM67 inhibition of DMBA-TPA–induced tumorigenesis. Microarray expression analysis of epidermal tissues revealed small sets of genes in which expression is both up-regulated by tumor promoter and down-regulated by TAM67. Among these, cyclooxygenase-2 (Cox-2/Ptgs2) and osteopontin (Opn/Spp1) are known to be functionally significant in driving carcinogenesis. Results identify both Cox-2 and Opn as transcriptional targets of TAM67 with CRE, but not NFκB sites important in the Cox-2 promoter and an AP-1 site important in the Opn promoter. [Cancer Res 2007;67(6):2430–8]