bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Dysfunctional Microvasculature as a Consequence of Shb Gene Inactivation Causes Impaired Tumor Growth
Authors: Funa Nina S. , Kriz Vitezslav , Zang Guangxiang , Calounova Gabriela , Åkerblom Björn , Mares Jaroslav , Larsson Erik , Sun Ying , Betsholtz Christer , Welsh Michael
Published: March 2024

Abstract
Shb (Src homology 2 protein B) is an adapter protein downstream of the vascular endothelial growth factor receptor receptor-2 (VEGFR-2). Previous experiments have suggested a role for Shb in endothelial cell function. Recently, the Shb gene was inactivated and Shb null mice were obtained on a mixed genetic background, but not on C57Bl6 mice. The present study was performed to address endothelial function in the Shb knockout mouse and its relevance for tumor angiogenesis. Tumor growth was retarded in Shb mutant mice, and this correlated with decreased angiogenesis both in tumors and in Matrigel plugs. Shb null mice display an abnormal endothelial ultrastructure in liver sinusoids and heart capillaries with cytoplasmic extensions projecting toward the lumen. Shb null heart VE-cadherin staining was less distinct than that of control heart, exhibiting in the former case a wavy and punctuate pattern. Experiments on isolated endothelial cells suggest that these changes could partly reflect cytoskeletal abnormalities. Vascular permeability was increased in Shb null mice in heart, kidney, and skin, whereas VEGF-stimulated vascular permeability was reduced in Shb null mice. It is concluded that Shb plays an important role in maintaining a functional vasculature in adult mice, and that interference with Shb signaling may provide novel means to regulate tumor angiogenesis. [Cancer Res 2009;69(5):2141–8]
Data from Analysis of DNA Copy Number Alterations in Ovarian Serous Tumors Identifies New Molecular Genetic Changes in Low-Grade and High-Grade Carcinomas
Authors: Kuo Kuan-Ting , Guan Bin , Feng Yuanjian , Mao Tsui-Lien , Chen Xu , Jinawath Natini , Wang Yue , Kurman Robert J. , Shih Ie-Ming , Wang Tian-Li
Published: March 2024

Abstract
Ovarian serous carcinoma, the most common and lethal type of ovarian cancer, is thought to develop from two distinct molecular pathways. High-grade (HG) serous carcinomas contain frequent TP53 mutations, whereas low-grade (LG) carcinomas arise from serous borderline tumors (SBT) and harbor mutations in KRAS/BRAF/ERBB2 pathway. However, the molecular alterations involved in the progression from SBT to LG carcinoma remain unknown. In addition, the extent of deletion of tumor suppressors in ovarian serous carcinomas has not been well studied. To further address these two issues, we assessed DNA copy number changes among affinity-purified tumor cells from 37 ovarian serous neoplasms including SBT, LG, and HG tumors using high-density 250K single nucleotide polymorphism arrays. Chromosomal instability index as measured by changes in DNA copy number was significantly higher in HG than in LG serous carcinomas. Hemizygous ch1p36 deletion was common in LG serous carcinomas but was rarely seen in SBT. This region contains several candidate tumor suppressors including miR-34a. In contrast, in HG serous carcinomas, significant numbers of amplifications and deletions, including homozygous deletions, were identified. Among homozygous deletions, loci containing Rb1, CDKN2A/B, CSMD1, and DOCK4 were most common, being present in 10.6%, 6.4%, 6.4%, and 4.3%, respectively, in independent 47 affinity-purified HG serous carcinomas. Except for the CDKN2A/B region, these homozygous deletions were not present in either SBT or LG tumors. Our study provides a genome-wide homozygous deletion profile in HG serous carcinomas, which can serve as a molecular foundation to study tumor suppressors in ovarian cancer. [Cancer Res 2009;69(9):4036–42]
Data from 14-3-3ζ Overexpression Defines High Risk for Breast Cancer Recurrence and Promotes Cancer Cell Survival
Authors: Neal Christopher L. , Yao Jun , Yang Wentao , Zhou Xiaoyan , Nguyen Nina T. , Lu Jing , Danes Christopher G. , Guo Hua , Lan Keng-Hsueh , Ensor Joe , Hittelman Walter , Hung Mien-Chie , Yu Dihua
Published: March 2024

Abstract
The ubiquitously expressed 14-3-3 proteins are involved in numerous important cellular functions. The loss of 14-3-3σ is a common event in breast cancer; however, the role of other 14-3-3s in breast cancer is unclear. Recently, we found that 14-3-3ζ overexpression occurs in early stage breast diseases and contributes to transformation of human mammary epithelial cells. Here, we show that 14-3-3ζ overexpression also persisted in invasive ductal carcinoma and contributed to the further progression of breast cancer. To examine the clinical effect of 14-3-3ζ overexpression in advanced stage breast cancer, we performed immunohistochemical analysis of 14-3-3ζ expression in primary breast carcinomas. 14-3-3ζ overexpression occurred in 42% of breast tumors and was determined to be an independent prognostic factor for reduced disease-free survival. 14-3-3ζ overexpression combined with ErbB2 overexpression and positive lymph node status identified a subgroup of patients at high risk for developing distant metastasis. To investigate whether 14-3-3ζ overexpression causally promotes breast cancer progression, we overexpressed 14-3-3ζ by stable transfection or reduced 14-3-3ζ expression by siRNA in cancer cell lines. Increased 14-3-3ζ expression enhanced anchorage-independent growth and inhibited stress-induced apoptosis, whereas down-regulation of 14-3-3ζ reduced anchorage-independent growth and sensitized cells to stress-induced apoptosis via the mitochondrial apoptotic pathway. Transient blockade of 14-3-3ζ expression by siRNA in cancer cells effectively reduced the onset and growth of tumor xenografts in vivo. Therefore, 14-3-3ζ overexpression is a novel molecular marker for disease recurrence in breast cancer patients and may serve as an effective therapeutic target in patients whose tumors overexpress 14-3-3ζ. [Cancer Res 2009;69(8):3425–32]
Data from Naringenin: A Potential Immunomodulator for Inhibiting Lung Fibrosis and Metastasis
Authors: Du Gangjun , Jin Lingtao , Han Xiaofen , Song Zihui , Zhang Hongyan , Liang Wei
Published: March 2024

Abstract
Patients with idiopathic pulmonary fibrosis have a high incidence of lung cancer and a worse prognosis for clinical treatment. A few molecules with antifibrosis properties have been shown promoting cancer progression in clinical trials. The objective of this study was to determine whether there is a similar tendency in mice as in human beings and whether these mice models may be used to find new therapeutic agents with antifibrotic properties but not cancer-promoting properties. We used bleomycin to induce pulmonary fibrosis in mice with or without naringenin treatment and measured the immune-associated lymphocytes and their secreted cytokines using flow cytometry and ELISA from lung tissue. Both passive and spontaneous metastatic models in bleomycin-treated C57BL/6 and BALB/c mice were used to test the hypothesis that mice with pulmonary fibrosis could have an increased risk of lung cancer and associated cancer progression. Here, we show that mice with lung fibrosis challenged using tumors show an increased incidence of lung metastasis and shorter life spans compared with the mice without lung fibrosis. A fibrotic environment in the lung results in increased abundance of transforming growth factor-β1 and CD4+CD25+Foxp3+ regulatory T cells and a decreased proportion of activated effector T cells. This grave immunosuppressive environment favors tumor localization and growth. Naringenin significantly reduces lung metastases in mice with pulmonary fibrosis and increases their survival by improving the immunosuppressive environment through down-regulating transforming growth factor-β1 and reducing regulatory T cells. Naringenin could be an ideal therapeutic agent in the treatment of both cancer and fibrosis. [Cancer Res 2009;69(7):3205–12]
Data from RGS17, an Overexpressed Gene in Human Lung and Prostate Cancer, Induces Tumor Cell Proliferation Through the Cyclic AMP-PKA-CREB Pathway
Authors: James Michael A. , Lu Yan , Liu Yan , Vikis Haris G. , You Ming
Published: March 2024

Abstract
We have identified RGS17 as a commonly induced gene in lung and prostate tumors. Through microarray and gene expression analysis, we show that expression of RGS17 is up-regulated in 80% of lung tumors, and also up-regulated in prostate tumors. Through knockdown and overexpression of RGS17 in tumor cells, we show that RGS17 confers a proliferative phenotype and is required for the maintenance of the proliferative potential of tumor cells. We show through exon microarray, transcript analysis, and functional assays that RGS17 promotes cyclic AMP (cAMP)-responsive element binding protein (CREB)-responsive gene expression, increases cAMP levels, and enhances forskolin-mediated cAMP production. Furthermore, inhibition of cAMP-dependent kinase prevents tumor cell proliferation, and proliferation is partially rescued by RGS17 overexpression. In the present study, we show a role for RGS17 in the maintenance of tumor cell proliferation through induction of cAMP signaling and CREB phosphorylation. The prevalence of the induction of RGS17 in tumor tissues of various types further implicates its importance in the maintenance of tumor growth. [Cancer Res 2009;69(5):2108–16]
Data from Sunitinib Inhibition of Stat3 Induces Renal Cell Carcinoma Tumor Cell Apoptosis and Reduces Immunosuppressive Cells
Authors: Xin Hong , Zhang Chunyan , Herrmann Andreas , Du Yan , Figlin Robert , Yu Hua
Published: March 2024

Abstract
The novel multitargeted tyrosine kinase inhibitor sunitinib is used as an antiangiogenic agent for the treatment of several types of cancer, including metastatic renal cell carcinoma (RCC). Sunitinib was shown to positively change the immunosuppressive phenotype in RCC patients. To improve its antitumor efficacy, and offer strategies for its combination with other approaches, it is critical to fully elucidate its mechanisms of action. We show that sunitinib induces tumor cell apoptosis and growth arrest in RCC tumor cells, which correlates with signal transducer and activator of transcription 3 (Stat3) activity inhibition. Sunitinib-mediated direct effects on tumor cells occur regardless of von Hippel-Lindau tumor suppressor gene status and hypoxia-inducible transcription factor-2α levels. Reduction of Stat3 activity enhances the antitumor effects of sunitinib, whereas expression of a constitutively activated Stat3 mutant rescues tumor cell death. Intravital multiphoton microscopy data show that sunitinib induces mouse Renca tumor cell apoptosis in vivo before tumor vasculature collapse. Sunitinib also inhibits Stat3 in Renca tumor–associated myeloid-derived suppressor cells (MDSC), down-regulates angiogenic gene expression, and reduces MDSCs and tumor T regulatory cells. These results suggest that Stat3 activity is important for RCC response to sunitinib, and Stat3 inhibition permits the direct proapoptotic activity of sunitinib on tumor cells and positive effects on tumor immunologic microenvironment. [Cancer Res 2009;69(6):2506–13]
Data from Elimination of Human Lung Cancer Stem Cells through Targeting of the Stem Cell Factor–c-kit Autocrine Signaling Loop
Authors: Levina Vera , Marrangoni Adele , Wang Tingting , Parikh Simul , Su Yunyun , Herberman Ronald , Lokshin Anna , Gorelik Elieser
Published: March 2024

Abstract
Cancer stem cells (CSC) are thought to be responsible for tumor initiation and tumor regeneration after chemotherapy. Previously, we showed that chemotherapy of non–small cell lung cancer (NSCLC) cells lines can select for outgrowth of highly tumorigenic and metastatic CSCs. The high malignancy of lung CSCs was associated with an efficient cytokine network. In this study, we provide evidence that blocking stem cell factor (SCF)–c-kit signaling is sufficient to inhibit CSC proliferation and survival promoted by chemotherapy. CSCs were isolated from NSCLC cell lines as tumor spheres under CSC-selective conditions and their stem properties were confirmed. In contrast to other tumor cells, CSCs expressed c-kit receptors and produced SCF. Proliferation of CSCs was inhibited by SCF-neutralizing antibodies or by imatinib (Gleevec), an inhibitor of c-kit. Although cisplatin treatment eliminated the majority of tumor cells, it did not eliminate CSCs, whereas imatinib or anti-SCF antibody destroyed CSCs. Significantly, combining cisplatin with imatinib or anti-SCF antibody prevented the growth of both tumor cell subpopulations. Our findings reveal an important role for the SCF–c-kit signaling axis in self-renewal and proliferation of lung CSCs, and they suggest that SCF–c-kit signaling blockade could improve the antitumor efficacy of chemotherapy of human NSCLC. Cancer Res; 70(1); 338–46
Data from GGAP2/PIKE-A Directly Activates Both the Akt and Nuclear Factor-κB Pathways and Promotes Prostate Cancer Progression
Authors: Cai Yi , Wang Jianghua , Li Rile , Ayala Gustavo , Ittmann Michael , Liu Mingyao
Published: March 2024

Abstract
GGAP2/PIKE-A is a GTP-binding protein that can enhance Akt activity. Increased activation of the AKT and nuclear factor-κB (NF-κB) pathways have been identified as critical steps in cancer initiation and progression in a variety of human cancers. We have found significantly increased expression GGAP2 in the majority of human prostate cancers and GGAP2 expression increases Akt activation in prostate cancer cells. Thus, increased GGAP2 expression is a common mechanism for enhancing the activity of the Akt pathway in prostate cancers. In addition, we have found that activated Akt can bind and phosphorylate GGAP2 at serine 629, which enhances GTP binding by GGAP2. Phosphorylated GGAP2 can bind the p50 subunit of NF-κB and enhances NF-κB transcriptional activity. When expressed in prostate cancer cells, GGAP2 enhances proliferation, foci formation, and tumor progression in vivo. Thus, increased GGAP2 expression, which is present in three quarters of human prostate cancers, can activate two critical pathways that have been linked to prostate cancer initiation and progression. [Cancer Res 2009;69(3):819–27]
Data from Histone Deacetylases Are Required for Androgen Receptor Function in Hormone-Sensitive and Castrate-Resistant Prostate Cancer
Authors: Welsbie Derek S. , Xu Jin , Chen Yu , Borsu Laetitia , Scher Howard I. , Rosen Neal , Sawyers Charles L.
Published: March 2024

Abstract
Transcriptional activity of the androgen receptor (AR) is crucial for growth and survival of prostate cancer even upon development of resistance to androgen ablation and antiandrogen therapies. Therefore, novel therapies that can suppress AR transcriptional activity when conventional hormone therapies fail are needed. Here, we show that histone deacetylase (HDAC) inhibitors, including SAHA (vorinostat) and LBH589, which are currently being tested in clinic, could be such a therapy. HDAC inhibitors block the AR-mediated transcriptional activation of many genes, including the TMPRSS2 gene involved in fusion with ETS family members in a majority of prostate cancers. Genetic knockdown of either HDAC1 or HDAC3 can also suppress expression of AR-regulated genes, recapitulating the effect of HDAC inhibitor treatment. Whereas HDAC inhibitor treatment can lower androgen receptor protein levels in prostate cancer cells, we show that independent of AR protein levels, HDAC inhibitors block AR activity through inhibiting the assembly of coactivator/RNA polymerase II complex after AR binds to the enhancers of target genes. Failed complex assembly is associated with a phase shift in the cyclical wave of AR recruitment that typically occurs in response to ligand treatment. HDAC inhibitors retain the ability to block AR activity in castration-resistant prostate cancer models and, therefore, merit clinical investigation in this setting. The HDAC-regulated AR target genes defined here can serve as biomarkers to ensure sufficient levels of HDAC inhibition. [Cancer Res 2009;69(3):958–66]
Data from Reactivation of Suppressed RhoB is a Critical Step for the Inhibition of Anaplastic Thyroid Cancer Growth
Authors: Marlow Laura A. , Reynolds Lisa A. , Cleland Alan S. , Cooper Simon J. , Gumz Michelle L. , Kurakata Shinichi , Fujiwara Kosaku , Zhang Ying , Sebo Thomas , Grant Clive , McIver Bryan , Wadsworth J. Trad , Radisky Derek C. , Smallridge Robert C. , Copland John A.
Published: March 2024

Abstract
Anaplastic thyroid carcinoma (ATC) is a highly aggressive form of the disease for which new therapeutic options are desperately needed. Previously, we showed that the high-affinity peroxisome proliferator–activated receptor γ (PPARγ) agonist, RS5444, inhibits cell proliferation of ATC cells via induction of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21). We show here that up-regulation of RhoB is a critical step in PPARγ-mediated activation of p21-induced cell stasis. Using multiple independently derived ATC cell lines, we found that treatment with RS5444 leads to the up-regulation of RhoB and subsequent activation of p21, and that silencing of RhoB by RNAi blocks the ability of RS5444 to induce p21 and to inhibit cell proliferation. Our results show that transcriptional regulation of RhoB by the nuclear transcription factor PPARγ is responsible for the induction of p21 mRNA and protein. We further implicate RhoB as a key signaling effector for the growth inhibition of ATC, as treatment with a histone deacetylase inhibitor shown to increase RhoB expression in lung cancer cells caused the up-regulation of RhoB in ATC cells accompanied by increased expression of p21 and inhibition of cell proliferation; this effect occurred even in ATC cells that were unresponsive to RS5444 due to a lack of expression of PPARγ. Our results implicate RhoB as a novel intermediate in critical signaling pathways and as an additional target for therapeutic intervention in ATC. [Cancer Res 2009;69(4):1536–44]
Data from TMPRSS2-ERG Gene Fusion Is Not Associated with Outcome in Patients Treated by Prostatectomy
Authors: Gopalan Anuradha , Leversha Margaret A. , Satagopan Jaya M. , Zhou Qin , Al-Ahmadie Hikmat A. , Fine Samson W. , Eastham James A. , Scardino Peter T. , Scher Howard I. , Tickoo Satish K. , Reuter Victor E. , Gerald William L.
Published: March 2024

Abstract
A significant number of prostate cancers have been shown to have recurrent chromosomal rearrangements resulting in the fusion of the androgen-regulated TMPRSS2 promoter to a member of the ETS transcription factor family, most commonly ERG. This results in ERG overexpression, which may have a direct causal role in prostate tumorigenesis or progression. However, the clinical significance of the rearrangement is unclear, and in particular, relationship to outcome has been inconsistent in recent reports. We analyzed TMPRSS2-ERG gene rearrangement status by fluorescence in situ hybridization in 521 cases of clinically localized surgically treated prostate cancer with 95 months of median follow-up and also in 40 unmatched metastases. Forty-two percent of primary tumors and 40% of metastases had rearrangements. Eleven percent had copy number increase (CNI) of the TMPRRS2-ERG region. Rearrangement alone was associated with lower grade, but not with stage, biochemical recurrence, metastases, or death. CNI with and without rearrangement was associated with high grade and advanced stage. Further, a subgroup of cancers with CNI and rearrangement by deletion, with two or more copies of the deleted locus, tended to be more clinically aggressive. DNA index assessment revealed that the majority of tumors with CNI of TMPRSS2-ERG had generalized aneuploidy/tetraploidy in contrast to tumors without TMPRSS2-ERG CNI, which were predominantly diploid. We therefore conclude that translocation of TMPRSS2-ERG is not associated with outcome, and the aggressive clinical features associated with CNI of chromosome 21 reflect generalized aneuploidy and are not due to CNI specifically of rearranged TMPRSS2-ERG. [Cancer Res 2009;69(4):1400–6]
Data from Atg5 Regulates Phenethyl Isothiocyanate–Induced Autophagic and Apoptotic Cell Death in Human Prostate Cancer Cells
Authors: Bommareddy Ajay , Hahm Eun-Ryeong , Xiao Dong , Powolny Anna A. , Fisher Alfred L. , Jiang Yu , Singh Shivendra V.
Published: March 2024

Abstract
Phenethyl isothiocyanate (PEITC) is a promising cancer chemopreventive agent but the mechanism of its anticancer effect is not fully understood. We now show, for the first time, that PEITC treatment triggers Atg5-dependent autophagic and apoptotic cell death in human prostate cancer cells. Exposure of PC-3 (androgen independent, p53 null) and LNCaP (androgen responsive, wild-type p53) human prostate cancer cells to PEITC resulted in several specific features characteristic of autophagy, including appearance of membranous vacuoles, formation of acidic vesicular organelles, and cleavage and recruitment of microtubule-associated protein 1 light chain 3 (LC3) to autophagosomes. A normal human prostate epithelial cell line (PrEC) was markedly more resistant toward PEITC-mediated cleavage and recruitment of LC3 compared with prostate cancer cells. Although PEITC treatment suppressed activating phosphorylations of Akt and mammalian target of rapamycin (mTOR), which are implicated in regulation of autophagy by different stimuli, processing and recruitment of LC3 was only partially/marginally reversed by ectopic expression of constitutively active Akt or overexpression of mTOR-positive regulator Rheb. The PEITC-mediated apoptotic DNA fragmentation was significantly attenuated in the presence of a pharmacologic inhibitor of autophagy (3-methyl adenine). Transient transfection of LNCaP and PC-3 cells with Atg5-specific small interfering RNA conferred significant protection against PEITC-mediated autophagy as well as apoptotic DNA fragmentation. A xenograft model using PC-3 cells and Caenorhabditis elegans expressing a lgg-1:GFP fusion protein provided evidence for occurrence of PEITC-induced autophagy in vivo. In conclusion, the present study indicates that Atg5 plays an important role in regulation of PEITC-induced autophagic and apoptotic cell death. [Cancer Res 2009;69(8):3704–12]
Data from Tobacco Smoke Induces Polycomb-Mediated Repression of Dickkopf-1 in Lung Cancer Cells
Authors: Hussain Mustafa , Rao Mahadev , Humphries Ashley E. , Hong Julie A. , Liu Fang , Yang Maocheng , Caragacianu Diana , Schrump David S.
Published: March 2024

Abstract
Limited information is available about epigenetic mechanisms by which cigarette smoke enhances the initiation and progression of lung cancer. To examine this issue, A549 and Calu-6 lung cancer cells were cultured in normal media with or without tobacco smoke condensate (TSC) under clinically relevant exposure conditions. Ten-day TSC exposure dramatically increased the tumorigenicity of lung cancer cells in nude mice. Microarray and quantitative reverse transcription-PCR (RT-PCR) experiments revealed that this phenomenon coincided with diminished expression of Dickkopf-1 (Dkk-1). Western blot, chromatin immunoprecipitation, methylation-specific PCR, and pyrosequencing experiments showed that repression of Dkk-1 coincided with decreased H4K16Ac, increased H3K27me3, and recruitment of SirT1, EZH2, SUZ12, and Bmi1 without DNA hypermethylation within the Dkk-1 promoter despite prolonged TSC exposures. Removal of TSC from culture media resulted in loss of promoter-associated polycomb repressor complexes and reexpression of Dkk-1. siRNA-mediated knockdown of EZH2 and SirT1 partially abrogated TSC-mediated inhibition of Dkk-1 expression. Western blot and quantitative RT-PCR array experiments showed that TSC exposure as well as knockdown of Dkk-1 activated Wnt signaling and significantly up-regulated Wnt5a in lung cancer cells. Knockdown of Dkk-1 recapitulated the dramatic protumorigenic effects of TSC exposure in Calu-6 cells. Despite the transient nature of Dkk-1 repression following TSC exposure in vitro, Dkk-1 remained silenced in tumor xenografts derived from TSC-treated Calu-6 cells. Collectively, these data provide evidence that cigarette smoke directly engages polycomb machinery to activate a signaling network implicated in maintenance of cancer stem cells. [Cancer Res 2009;69(8):3570–8]
Data from Oncogenesis Caused by Loss of the SNF5 Tumor Suppressor Is Dependent on Activity of BRG1, the ATPase of the SWI/SNF Chromatin Remodeling Complex
Authors: Wang Xi , Sansam Courtney G. , Thom Christopher S. , Metzger Daniel , Evans Julia A. , Nguyen Phuong T.L. , Roberts Charles W.M.
Published: March 2024

Abstract
Alterations in chromatin play an important role in oncogenic transformation, although the underlying mechanisms are often poorly understood. The SWI/SNF complex contributes to epigenetic regulation by using the energy of ATP hydrolysis to remodel chromatin and thus regulate transcription of target genes. SNF5, a core subunit of the SWI/SNF complex, is a potent tumor suppressor that is specifically inactivated in several types of human cancer. However, the mechanism by which SNF5 mutation leads to cancer and the role of SNF5 within the SWI/SNF complex remain largely unknown. It has been hypothesized that oncogenesis in the absence of SNF5 occurs due to a loss of function of the SWI/SNF complex. Here, we show, however, distinct effects for inactivation of Snf5 and the ATPase subunit Brg1 in primary cells. Further, using both human cell lines and mouse models, we show that cancer formation in the absence of SNF5 does not result from SWI/SNF inactivation but rather that oncogenesis is dependent on continued presence of BRG1. Collectively, our results show that cancer formation in the absence of SNF5 is dependent on the activity of the residual BRG1-containing SWI/SNF complex. These findings suggest that, much like the concept of oncogene addiction, targeted inhibition of SWI/SNF ATPase activity may be an effective therapeutic approach for aggressive SNF5-deficient human tumors. [Cancer Res 2009;69(20):8094–101]
Data from The Putative Tumor Suppressor microRNA-101 Modulates the Cancer Epigenome by Repressing the Polycomb Group Protein EZH2
Authors: Friedman Jeffrey M. , Liang Gangning , Liu Chun-Chi , Wolff Erika M. , Tsai Yvonne C. , Ye Wei , Zhou Xianghong , Jones Peter A.
Published: March 2024

Abstract
The Polycomb Repressive Complex 2 (PRC2) mediates epigenetic gene silencing by trimethylating histone H3 lysine 27 (H3K27me3) and is known to aberrantly silence tumor suppressor genes in cancer. EZH2, the catalytic subunit of PRC2, enhances tumorigenesis and is commonly overexpressed in several types of cancer. Our microRNA profiling of bladder transitional cell carcinoma (TCC) patient samples revealed that microRNA-101 (miR-101) is down-regulated in TCC, and we showed that miR-101 inhibits cell proliferation and colony formation in TCC cell lines. Furthermore, our results confirm that miR-101 directly represses EZH2 and stable EZH2 knockdowns in TCC cell lines create a similar growth suppressive phenotype. This suggests that abnormal down-regulation of miR-101 could lead to the overexpression of EZH2 frequently seen in cancer. We conclude that miR-101 may be a potent tumor suppressor by altering global chromatin structure through repression of EZH2. [Cancer Res 2009;69(6):2623–9]
Data from The L6 Protein TM4SF1 Is Critical for Endothelial Cell Function and Tumor Angiogenesis
Authors: Shih Shou-Ching , Zukauskas Andrew , Li Dan , Liu Guanmei , Ang Lay-Hong , Nagy Janice A. , Brown Lawrence F. , Dvorak Harold F.
Published: March 2024

Abstract
Transmembrane-4-L-six-family-1 (TM4SF1) was originally described as a cancer cell protein. Here, we show that it is highly expressed in the vascular endothelium of human cancers and in a banded pattern in the filopodia of cultured endothelial cells (EC). TM4SF1 knockdown prevented filopodia formation, inhibited cell mobility, blocked cytokinesis, and rendered EC senescent. Integrin-α5 and integrin-β1 subunits gave a similar staining pattern and interacted constitutively with TM4SF1, whereas integrin subunits often associated with angiogenesis (αV, β3, β5) interacted with TM4SF1 only after vascular endothelial growth factor (VEGF)-A or thrombin stimulation. TM4SF1 knockdown substantially inhibited maturation of VEGF-A164–induced angiogenesis. Thus, TM4SF1 is a key regulator of EC function in vitro and of pathologic angiogenesis in vivo and is potentially an attractive target for antiangiogenesis therapy. [Cancer Res 2009;69(8):3272–7]
Data from A Novel Androgen Receptor Splice Variant Is Up-regulated during Prostate Cancer Progression and Promotes Androgen Depletion–Resistant Growth
Authors: Guo Zhiyong , Yang Xi , Sun Feng , Jiang Richeng , Linn Douglas E. , Chen Hege , Chen Hegang , Kong Xiangtian , Melamed Jonathan , Tepper Clifford G. , Kung Hsing-Jien , Brodie Angela M.H. , Edwards Joanne , Qiu Yun
Published: March 2024

Abstract
The androgen receptor (AR) plays a key role in progression to incurable androgen ablation–resistant prostate cancer (PCA). We have identified three novel AR splice variants lacking the ligand-binding domain (designated as AR3, AR4, and AR5) in hormone-insensitive PCA cells. AR3, one of the major splice variants expressed in human prostate tissues, is constitutively active, and its transcriptional activity is not regulated by androgens or antiandrogens. Immunohistochemistry analysis on tissue microarrays containing 429 human prostate tissue samples shows that AR3 is significantly up-regulated during PCA progression and AR3 expression level is correlated with the risk of tumor recurrence after radical prostatectomy. Overexpression of AR3 confers ablation-independent growth of PCA cells, whereas specific knockdown of AR3 expression (without altering AR level) in hormone-resistant PCA cells attenuates their growth under androgen-depleted conditions in both cell culture and xenograft models, suggesting an indispensable role of AR3 in ablation-independent growth of PCA cells. Furthermore, AR3 may play a distinct, yet essential, role in ablation-independent growth through the regulation of a unique set of genes, including AKT1, which are not regulated by the prototype AR. Our data suggest that aberrant expression of AR splice variants may be a novel mechanism underlying ablation independence during PCA progression, and AR3 may serve as a prognostic marker to predict patient outcome in response to hormonal therapy. Given that these novel AR splice variants are not inhibited by currently available antiandrogen drugs, development of new drugs targeting these AR isoforms may potentially be effective for treatment of ablation-resistant PCA. [Cancer Res 2009;69(6):2305–13]
Data from Characterization of a Novel Mitogen-Activated Protein Kinase Kinase 1/2 Inhibitor with a Unique Mechanism of Action for Cancer Therapy
Authors: Daouti Sherif , Wang Huisheng , Li Wen-hui , Higgins Brian , Kolinsky Kenneth , Packman Kathryn , Specian Anthony , Kong Norman , Huby Nicholas , Wen Yang , Xiang Qing , Podlaski Frank J. , He Yang , Fotouhi Nader , Heimbrook David , Niu Huifeng
Published: March 2024

Abstract
The mitogen-activated protein kinase (MAPK) signal transduction pathway plays a central role in regulating tumor cell growth, survival, differentiation, and angiogenesis. The key components of the Ras/Raf/MEK/ERK signal module are frequently altered in human cancers. Targeting this pathway represents a promising anticancer strategy. Small molecule inhibitors targeting MEK1/2 have shown promise in the clinic; however, ultimate clinical proof-of-concept remains elusive. Here, we report a potent and highly selective non–ATP-competitive MEK1/2 inhibitor, RO4927350, with a novel chemical structure and unique mechanism of action. It selectively blocks the MAPK pathway signaling both in vitro and in vivo, which results in significant antitumor efficacy in a broad spectrum of tumor models. Compared with previously reported MEK inhibitors, RO4927350 inhibits not only ERK1/2 but also MEK1/2 phosphorylation. In cancer cells, high basal levels of phospho-MEK1/2 rather than phospho-ERK1/2 seem to correlate with greater sensitivity to RO4927350. Furthermore, RO4927350 prevents a feedback increase in MEK phosphorylation, which has been observed with other MEK inhibitors. We show that B-Raf rather than C-Raf plays a critical role in the feedback regulation. The unique MAPK signaling blockade mediated by RO4927350 in cancer may reduce the risk of developing drug resistance. Thus, RO4927350 represents a novel therapeutic modality in cancers with aberrant MAPK pathway activation. [Cancer Res 2009;69(5):1924–32
Data from Acyl-CoA Synthetase VL3 Knockdown Inhibits Human Glioma Cell Proliferation and Tumorigenicity
Authors: Pei Zhengtong , Sun Peng , Huang Ping , Lal Bachchu , Laterra John , Watkins Paul A.
Published: March 2024

Abstract
The contribution of lipid metabolic pathways to malignancy is poorly understood. Expression of the fatty acyl-CoA synthetase ACSVL3 was found to be markedly elevated in clinical malignant glioma specimens but nearly undetectable in normal glia. ACSVL3 levels correlated with the malignant behavior of human glioma cell lines and glioma cells propagated as xenografts. ACSVL3 expression was induced by the activation of oncogenic receptor tyrosine kinases (RTK) c-Met and epidermal growth factor receptor. Inhibiting c-Met activation with neutralizing anti–hepatocyte growth factor monoclonal antibodies reduced ACSVL3 expression concurrent with tumor growth inhibition in vivo. ACSVL3 expression knockdown using RNA interference, which decreased long-chain fatty acid activation, inhibited anchorage-dependent and anchorage-independent glioma cell growth by ∼70% and ∼90%, respectively. ACSVL3-depleted cells were less tumorigenic than control cells, and subcutaneous xenografts grew ∼60% slower than control tumors. Orthotopic xenografts produced by ACSVL3-depleted cells were 82% to 86% smaller than control xenografts. ACSVL3 knockdown disrupted Akt function as evidenced by RTK-induced transient decreases in total and phosphorylated Akt, as well as glycogen synthase kinase 3β, via a caspase-dependent mechanism. Expressing constitutively active myr-Akt rescued cells from the anchorage-dependent and anchorage-independent growth inhibitory effects of ACSVL3 depletion. These studies show that ACSVL3 maintains oncogenic properties of malignant glioma cells via a mechanism that involves, in part, the regulation of Akt function. [Cancer Res 2009;69(24):9175–82]
Data from Epidermal Growth Factor Receptor and PTEN Modulate Tissue Factor Expression in Glioblastoma through JunD/Activator Protein-1 Transcriptional Activity
Authors: Rong Yuan , Belozerov Vladimir E. , Tucker-Burden Carol , Chen Gang , Durden Donald L. , Olson Jeffrey J. , Van Meir Erwin G. , Mackman Nigel , Brat Daniel J.
Published: March 2024

Abstract
Hypoxia and necrosis are fundamental features of glioblastoma (GBM) and their emergence is critical for the rapid biological progression of this fatal tumor; yet, underlying mechanisms are poorly understood. We have suggested that vaso-occlusion following intravascular thrombosis could initiate or propagate hypoxia and necrosis in GBM. Tissue factor (TF), the main cellular initiator of coagulation, is overexpressed in GBMs and likely favors a thrombotic microenvironment. Epidermal growth factor receptor (EGFR) amplification and PTEN loss are two common genetic alterations seen in GBM but not in lower-grade astrocytomas that could be responsible for TF up-regulation. The most frequent EGFR mutation in GBM involves deletion of exons 2 to 7, resulting in the expression of a constitutively active receptor, EGFRvIII. Here, we show that overexpression of EGFR or EGFRvIII in human glioma cells causes increased basal TF expression and that stimulation of EGFR by its ligand, EGF, leads to a marked dose-dependent up-regulation of TF. In all cases, increased TF expression led to accelerated plasma coagulation in vitro. EGFR-mediated TF expression depended most strongly on activator protein-1 (AP-1) transcriptional activity and was associated with c-Jun NH2-terminal kinase (JNK) and JunD activation. Restoration of PTEN expression in PTEN-deficient GBM cells diminished EGFR-induced TF expression by inhibiting JunD/AP-1 transcriptional activity. PTEN mediated this effect by antagonizing phosphatidylinositol 3-kinase activity, which in turn attenuated both Akt and JNK activities. These mechanisms are likely at work in vivo, as EGFR expression was highly correlated with TF expression in human high-grade astrocytoma specimens. [Cancer Res 2009;69(6):2540–9]
Data from Attenuated Transforming Growth Factor β Signaling Promotes Nuclear Factor-κB Activation in Head and Neck Cancer
Authors: Cohen Jonah , Chen Zhong , Lu Shi-Long , Yang Xin Ping , Arun Pattatheyil , Ehsanian Reza , Brown Matthew S. , Lu Hai , Yan Bin , Diallo Oumou , Wang Xiao-Jing , Van Waes Carter
Published: March 2024

Abstract
Although constitutively activated nuclear factor-κB (NF-κB), attenuated transforming growth factor β (TGFβ) signaling, and TP53 mutations frequently occur in human cancers, how these pathways interact and together contribute to malignancy remains uncertain. Here, we found an association between overexpression of NF-κB–related genes, reduced expression of TGFβ receptor (TβR) subunits and downstream targets, and TP53 genotype in head and neck squamous cell carcinoma (HNSCC). In response to recombinant TGFβ1, both growth inhibition and TGFβ target gene modulation were attenuated or absent in a panel of human HNSCC lines. However, in HNSCC cells that retained residual TGFβ signaling, TGFβ1 inhibited both constitutive and tumor necrosis factor α–stimulated NF-κB activity. Furthermore, HNSCC lines overexpressing mutant (mt) TP53 and human tumor specimens with positive TP53 nuclear staining exhibited reduced TβRII and knocking down mtTP53 induced TβRII, increasing TGFβ downstream gene expression while inhibiting proinflammatory NF-κB target gene expression. Transfection of ectopic TβRII directly restored TGFβ signaling while inhibiting inhibitor κBα degradation and suppressing serine-536 phosphorylation of NF-κB p65 and NF-κB transcriptional activation, linking these alterations. Finally, experiments with TβRII conditional knockout mice show that abrogation of TGFβ signaling promotes the sustained induction of NF-κB and its proinflammatory target genes during HNSCC tumorigenesis and progression. Together, these findings elucidate a regulatory framework in which attenuated TGFβ signaling promotes NF-κB activation and squamous epithelial malignancy in the setting of altered TP53 status. [Cancer Res 2009;69(8):3415–24]
Data from Inhibition of NOTCH Signaling by Gamma Secretase Inhibitor Engages the RB Pathway and Elicits Cell Cycle Exit in T-Cell Acute Lymphoblastic Leukemia Cells
Authors: Rao Sudhir S. , O'Neil Jennifer , Liberator Cole D. , Hardwick James S. , Dai Xudong , Zhang Theresa , Tyminski Edyta , Yuan Jing , Kohl Nancy E. , Richon Victoria M. , Van der Ploeg Lex H.T. , Carroll Pamela M. , Draetta Giulio F. , Look A. Thomas , Strack Peter R. , Winter Christopher G.
Published: March 2024

Abstract
NOTCH signaling is deregulated in the majority of T-cell acute lymphoblastic leukemias (T-ALL) as a result of activating mutations in NOTCH1. Gamma secretase inhibitors (GSI) block proteolytic activation of NOTCH receptors and may provide a targeted therapy for T-ALL. We have investigated the mechanisms of GSI sensitivity across a panel of T-ALL cell lines, yielding an approach for patient stratification based on pathway activity and also providing a rational combination strategy for enhanced response to GSI. Whereas the NOTCH1 mutation status does not serve as a predictor of GSI sensitivity, a gene expression signature of NOTCH pathway activity does correlate with response, and may be useful in the selection of patients more likely to respond to GSI. Furthermore, inhibition of the NOTCH pathway activity signature correlates with the induction of the cyclin-dependent kinase inhibitors CDKN2D (p19INK4d) and CDKN1B (p27Kip1), leading to derepression of RB and subsequent exit from the cell cycle. Consistent with this evidence of cell cycle exit, short-term exposure of GSI resulted in sustained molecular and phenotypic effects after withdrawal of the compound. Combination treatment with GSI and a small molecule inhibitor of CDK4 produced synergistic growth inhibition, providing evidence that GSI engagement of the CDK4/RB pathway is an important mechanism of GSI action and supports further investigation of this combination for improved efficacy in treating T-ALL. [Cancer Res 2009;69(7):3060–8]
Data from EGFRvIII Antibody–Conjugated Iron Oxide Nanoparticles for Magnetic Resonance Imaging–Guided Convection-Enhanced Delivery and Targeted Therapy of Glioblastoma
Authors: Hadjipanayis Costas G. , Machaidze Revaz , Kaluzova Milota , Wang Liya , Schuette Albert J. , Chen Hongwei , Wu Xinying , Mao Hui
Published: March 2024

Abstract
The magnetic nanoparticle has emerged as a potential multifunctional clinical tool that can provide cancer cell detection by magnetic resonance imaging (MRI) contrast enhancement as well as targeted cancer cell therapy. A major barrier in the use of nanotechnology for brain tumor applications is the difficulty in delivering nanoparticles to intracranial tumors. Iron oxide nanoparticles (IONP; 10 nm in core size) conjugated to a purified antibody that selectively binds to the epidermal growth factor receptor (EGFR) deletion mutant (EGFRvIII) present on human glioblastoma multiforme (GBM) cells were used for therapeutic targeting and MRI contrast enhancement of experimental glioblastoma, both in vitro and in vivo, after convection-enhanced delivery (CED). A significant decrease in glioblastoma cell survival was observed after nanoparticle treatment and no toxicity was observed with treatment of human astrocytes (P < 0.001). Lower EGFR phosphorylation was found in glioblastoma cells after EGFRvIIIAb-IONP treatment. Apoptosis was determined to be the mode of cell death after treatment of GBM cells and glioblastoma stem cell–containing neurospheres with EGFRvIIIAb-IONPs. MRI-guided CED of EGFRvIIIAb-IONPs allowed for the initial distribution of magnetic nanoparticles within or adjacent to intracranial human xenograft tumors and continued dispersion days later. A significant increase in animal survival was found after CED of magnetic nanoparticles (P < 0.01) in mice implanted with highly tumorigenic glioblastoma xenografts (U87ΔEGFRvIII). IONPs conjugated to an antibody specific to the EGFRvIII deletion mutant constitutively expressed by human glioblastoma tumors can provide selective MRI contrast enhancement of tumor cells and targeted therapy of infiltrative glioblastoma cells after CED. Cancer Res; 70(15); 6303–12. ©2010 AACR.
Data from PIK3CA Mutation Uncouples Tumor Growth and Cyclin D1 Regulation from MEK/ERK and Mutant KRAS Signaling
Authors: Halilovic Ensar , She Qing-Bai , Ye Qing , Pagliarini Raymond , Sellers William R. , Solit David B. , Rosen Neal
Published: March 2024

Abstract
Mutational activation of KRAS is a common event in human tumors. Identification of the key signaling pathways downstream of mutant KRAS is essential for our understanding of how to pharmacologically target these cancers in patients. We show that PD0325901, a small-molecule MEK inhibitor, decreases MEK/ERK pathway signaling and destabilizes cyclin D1, resulting in significant anticancer activity in a subset of KRAS mutant tumors in vitro and in vivo. Mutational activation of PIK3CA, which commonly co-occurs with KRAS mutation, provides resistance to MEK inhibition through reactivation of AKT signaling. Genetic ablation of the mutant PIK3CA allele in MEK inhibitor–resistant cells restores MEK pathway sensitivity, and re-expression of mutant PIK3CA reinstates the resistance, highlighting the importance of this mutation in resistance to therapy in human cancers. In KRAS mutant tumors, PIK3CA mutation restores cyclin D1 expression and G1-S cell cycle progression so that they are no longer dependent on KRAS and MEK/ERK signaling. Furthermore, the growth of KRAS mutant tumors with coexistent PIK3CA mutations in vivo is profoundly inhibited with combined pharmacologic inhibition of MEK and AKT. These data suggest that tumors with both KRAS and phosphoinositide 3-kinase mutations are unlikely to respond to the inhibition of the MEK pathway alone but will require effective inhibition of both MEK and phosphoinositide 3-kinase/AKT pathway signaling. Cancer Res; 70(17); 6804–14. ©2010 AACR.
Data from Notch Signaling Determines the M1 versus M2 Polarization of Macrophages in Antitumor Immune Responses
Authors: Wang Yao-Chun , He Fei , Feng Fan , Liu Xiao-Wei , Dong Guang-Ying , Qin Hong-Yan , Hu Xing-Bin , Zheng Min-Hua , Liang Liang , Feng Lei , Liang Ying-Min , Han Hua
Published: March 2024

Abstract
Macrophages are important tumor-infiltrating cells and play pivotal roles in tumor growth and metastasis. Macrophages participate in immune responses to tumors in a polarized manner: classic M1 macrophages produce interleukin (IL) 12 to promote tumoricidal responses, whereas M2 macrophages produce IL10 and help tumor progression. The mechanisms governing macrophage polarization are unclear. Here, we show that the M2-like tumor-associated macrophages (TAM) have a lower level of Notch pathway activation in mouse tumor models. Forced activation of Notch signaling increased M1 macrophages which produce IL12, no matter whether M1 or M2 inducers were applied. When Notch signaling was blocked, the M1 inducers induced M2 response in the expense of M1. Macrophages deficient in canonical Notch signaling showed TAM phenotypes. Forced activation of Notch signaling in macrophages enhanced their antitumor capacity. We further show that RBP-J–mediated Notch signaling regulates the M1 versus M2 polarization through SOCS3. Therefore, Notch signaling plays critical roles in the determination of M1 versus M2 polarization of macrophages, and compromised Notch pathway activation will lead to the M2-like TAMs. These results provide new insights into the molecular mechanisms of macrophage polarization and shed light on new therapies for cancers through the modulation of macrophage polarization through the Notch signaling. Cancer Res; 70(12); 4840–9. ©2010 AACR.
Data from Breast Carcinoma–Associated Fibroblasts Rarely Contain p53 Mutations or Chromosomal Aberrations
Authors: Hosein Abdel Nasser , Wu Min , Arcand Suzanna L. , Lavallée Sylvie , Hébert Josée , Tonin Patricia N. , Basik Mark
Published: March 2024

Abstract
It has become increasingly clear that the cells within the tumor microenvironment play a critical role in cancer growth and metastasis. Studies in experimental models suggest that carcinoma-associated fibroblasts (CAF) differ from normal fibroblasts and are capable of promoting cancer progression through a variety of mechanisms. At present, a definitive view is lacking on whether genomic abnormalities are present and whether they might underlie the observed phenotypic differences. This study reports the molecular analysis of the largest series of breast CAFs reported to date, with an array comparative genomic hybridization–based DNA copy number analysis of cultured CAFs derived from 25 freshly resected human breast cancers. We found DNA copy number changes consisting of the whole arm of chromosomes 6p and 9p plus interstitial 4q loss in only one sample. No abnormalities were observed in non–tumor-associated fibroblast counterparts. Karyotyping of the same CAF revealed further chromosomal abnormalities, which included clonal loss of chromosomes, chromosomal duplications, and less frequent chromosomal rearrangements. These abnormalities were not associated with alterations in the global gene expression profile of this particular CAF, relative to its non–tumor-associated fibroblast counterpart. Moreover, this particular patient's CAF also displayed the only p53 mutation in the cohort, the first time such a mutation has been reported in freshly cultured human CAFs. These findings argue that the procancerous effects of CAFs are unlikely to be due to DNA copy number–type genomic abnormalities in the CAFs themselves. As such, breast CAFs should be mainly regarded as genomically stable cellular constituents that exist within complex cancer microenvironments. Cancer Res; 70(14); 5770–7. ©2010 AACR.