bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from p53-Responsive MicroRNAs 192 and 215 Are Capable of Inducing Cell Cycle Arrest
Authors: Braun Christian J. , Zhang Xin , Savelyeva Irina , Wolff Sonja , Moll Ute M. , Schepeler Troels , Ørntoft Torben F. , Andersen Claus L. , Dobbelstein Matthias
Published: March 2024

Abstract
microRNAs provide a novel layer of regulation for gene expression by interfering with the stability and/or translation of specific target mRNAs. Overall levels of microRNAs are frequently down-regulated in cancer cells, and reducing general microRNA processing increases cancerogenesis in transgenic models, suggesting that at least some microRNAs might act as effectors in tumor suppression. Accordingly, the tumor suppressor p53 up-regulates miR-34a, a microRNA that contributes to apoptosis and acute senescence. Here, we used array hybridization to find that p53 induces two additional, mutually related clusters of microRNAs, leading to the up-regulation of miR-192, miR-194, and miR-215. The same microRNAs were detected at high levels in normal colon tissue but were severely reduced in many colon cancer samples. On the other hand, miR-192 and its cousin miR-215 can each contribute to enhanced CDKN1A/p21 levels, colony suppression, cell cycle arrest, and cell detachment from a solid support. These effects were partially dependent on the presence of wild-type p53. Antagonizing endogenous miR-192 attenuated 5-fluorouracil–induced accumulation of p21. Hence, miR-192 and miR-215 can act as effectors as well as regulators of p53; they seem to suppress cancerogenesis through p21 accumulation and cell cycle arrest. [Cancer Res 2008;68(24):10094–104]
Data from Containment of Tumor-Colonizing Bacteria by Host Neutrophils
Authors: Westphal Kathrin , Leschner Sara , Jablonska Jadwiga , Loessner Holger , Weiss Siegfried
Published: March 2024

Abstract
Administration of facultative anaerobic bacteria like Salmonella typhimurium, Shigella flexneri, and Escherichia coli to tumor-bearing mice leads to a preferential accumulation and proliferation of the microorganisms within the solid tumor. Until now, all known tumor-targeting bacteria have shown poor dissemination inside the tumors. They accumulate almost exclusively in large necrotic areas and spare a rim of viable tumor cells. Interestingly, the bacteria-containing necrotic region is separated from viable tumor cells by a barrier of host neutrophils that have immigrated into the tumor. We here report that depletion of host neutrophils results in a noticeably higher total number of bacteria in the tumor and that bacteria were now also able to migrate into vital tumor tissue. Most remarkably, an increase in the size of the necrosis was observed, and complete eradication of established tumors could be observed under these conditions. Thus, bacteria-mediated tumor therapy can be amplified by depletion of host neutrophils. [Cancer Res 2008;68(8):2952–60]
Data from A Key Tyrosine (Y1494) in the β4 Integrin Regulates Multiple Signaling Pathways Important for Tumor Development and Progression
Authors: Dutta Udayan , Shaw Leslie M.
Published: March 2024

Abstract
Expression of the α6β4 integrin is associated with poor patient prognosis and reduced survival in a variety of human cancers. In recent years, a limited number of in vivo studies have examined the contribution of this integrin receptor to cancer progression and they have revealed that the α6β4 integrin plays a multifaceted role in regulating tumor development and progression. In the current study, we investigated the mechanism by which one tyrosine residue in the β4 subunit cytoplasmic domain, Y1494, contributes to the tumor-promoting functions of the α6β4 integrin in vivo. We show that Y1494 participates in the stimulation of diverse signaling pathways that promote α6β4-dependent tumor growth and invasion. Mutation of Y1494 inhibits the ability of the α6β4 integrin to support anchorage-independent growth in vitro and tumor development and angiogenesis in vivo, a result that mimics the loss of total expression of the β4 subunit. Our results support the hypothesis that Y1494 regulates α6β4-dependent anchorage-independent growth through activation of the extracellular signal-regulated kinase 1/2 signaling pathway, and invasion through the combined activation of phosphatidylinositol 3-kinase and Src. Collectively, our results identify Y1494 as a major regulatory site for signaling from the α6β4 integrin to promote tumor development and progression. [Cancer Res 2008;68(21):8779–87]
Data from Negative Regulation of AKT Activation by BRCA1
Authors: Xiang Tao , Ohashi Amiko , Huang Yuping , Pandita Tej K. , Ludwig Thomas , Powell Simon N. , Yang Qin
Published: March 2024

Abstract
The breast cancer susceptibility gene 1 (BRCA1) plays a key role in mammary tumorigenesis. However, the reasons why silencing the Brca1 gene leads to tumorigenesis are not clearly understood. We report here that BRCA1 deficiency activates the AKT oncogenic pathway, one of the most common alterations associated with human malignancy. Mutation of Brca1 gene increases the phosphorylation and the kinase activity of AKT. The BRCA1-BRCT domains bind to phosphorylated AKT (pAKT) and lead to its ubiquitination toward protein degradation. BRCA1 mutant cells lacking the BRCT repeats accumulate nuclear pAKT and consequently inactivate the transcription functions of FOXO3a, a main nuclear target of pAKT. Our results show that BRCA1 is a negative regulator of the AKT pathway and imply the significance of the BRCA1/AKT pathway in tumorigenesis. [Cancer Res 2008;68(24):10040–4]
Data from Analysis of the Human Cancer Glycome Identifies a Novel Group of Tumor-Associated N-Acetylglucosamine Glycan Antigens
Authors: Satomaa Tero , Heiskanen Annamari , Leonardsson Iréne , Ångström Jonas , Olonen Anne , Blomqvist Maria , Salovuori Noora , Haglund Caj , Teneberg Susann , Natunen Jari , Carpén Olli , Saarinen Juhani
Published: March 2024

Abstract
The cell surface is covered by a dense layer of protein- and lipid-linked glycans. Although it has been known that distinct glycan structures are associated with cancer, the whole spectrum of cancer-associated glycans has remained undiscovered. In the present study, we analyzed the protein-linked cancer glycome by matrix-assisted laser desorption/ionization time-of-flight mass spectrometric glycan profiling of cancer patient tissue samples. In lung cancer, we detected accumulation of a novel group of tumor-associated glycans. These protein-linked glycans carried abnormal nonreducing terminal β-N-acetyl-d-glucosamine (GlcNAc) residues. A similar phenomenon was also detected in structural analyses of tumor-derived glycosphingolipids. This showed that glycan biosynthesis may dramatically change in cancer and that direct glycome analysis can detect the resulting marker glycans. Based on the structural knowledge, we further devised a covalent labeling technique for the detection of GlcNAc-expressing tumors with a specific transferase enzyme. In normal tissues, terminal GlcNAc antigens are capped by galactosylation. Similarly to common cancer-associated glycan antigens T, Tn, and sialyl-Tn, the newly discovered GlcNAc antigens result from incomplete glycosylation. In conclusion, the identified terminal GlcNAc glycans should be recognized as a novel class of tumor markers. [Cancer Res 2009;69(14):5811–9]
Data from Regulation of Cyclin D1 RNA Stability by SNIP1
Authors: Bracken Cameron P. , Wall Steven J. , Barré Benjamin , Panov Kostya I. , Ajuh Paul M. , Perkins Neil D.
Published: March 2024

Abstract
Cyclin D1 expression represents one of the key mitogen-regulated events during the G1 phase of the cell cycle, whereas Cyclin D1 overexpression is frequently associated with human malignancy. Here, we describe a novel mechanism regulating Cyclin D1 levels. We find that SNIP1, previously identified as a regulator of Cyclin D1 expression, does not, as previously thought, primarily function as a transcriptional coactivator for this gene. Rather, SNIP1 plays a critical role in cotranscriptional or posttranscriptional Cyclin D1 mRNA stability. Moreover, we show that the majority of nucleoplasmic SNIP1 is present within a previously undescribed complex containing SkIP, THRAP3, BCLAF1, and Pinin, all proteins with reported roles in RNA processing and transcriptional regulation. We find that this complex, which we have termed the SNIP1/SkIP–associated RNA-processing complex, is coordinately recruited to both the 3′ end of the Cyclin D1 gene and Cyclin D1 RNA. Significantly, SNIP1 is required for the further recruitment of the RNA processing factor U2AF65 to both the Cyclin D1 gene and RNA. This study shows a novel mechanism regulating Cyclin D1 expression and offers new insight into the role of SNIP1 and associated proteins as regulators of proliferation and cancer. [Cancer Res 2008;68(18):7621–8]
Data from Vascular Endothelial Growth Factor-C and C-C Chemokine Receptor 7 in Tumor Cell–Lymphatic Cross-talk Promote Invasive Phenotype
Authors: Issa Amine , Le Thomas X. , Shoushtari Alexander N. , Shields Jacqueline D. , Swartz Melody A.
Published: March 2024

Abstract
Most carcinomas spread to distant sites through lymphatic vessels. Several preclinical and clinical studies have shown a positive correlation between the incidence of lymph node metastasis and secretion of the lymphatic growth factor vascular endothelial growth factor-C (VEGF-C) by tumor cells, suggesting tumor lymphangiogenesis as an escape mechanism. However, recent evidence has shown VEGF receptor-3 (VEGFR-3) expression on tumor cells and autocrine signaling, which increase metastatic potential. Furthermore, there is growing evidence implicating lymphatic-homing chemokine receptors, particularly C-C chemokine receptor 7 (CCR7), in lymph node metastasis. We report here that expressions of VEGF-C and CCR7 by tumor cells act synergistically to promote their invasion toward lymphatics. First, VEGF-C acts to increase lymphatic secretion of CCL21, which in turn drives CCR7-dependent tumor chemoinvasion toward lymphatics. Second, VEGF-C acts in an autocrine fashion to increase tumor invasiveness by increasing the proteolytic activity and motility of tumor cells in a three-dimensional matrix. Both of these effects are VEGFR-3 dependent and evident only in three-dimensional environments. We further verified that VEGF-C induces lymphatic CCL21 up-regulation in vivo by direct injection of VEGF-C protein intradermally in the mouse. Taken together, these results bridge the prometastatic functions of CCR7 and VEGF-C in tumors and show that, beyond lymphangiogenesis, VEGF-C promotes tumor invasion toward lymphatics by both autocrine and CCR7-dependent paracrine signaling mechanisms, which may be a significant cause of lymph node metastasis. [Cancer Res 2009;69(1):349–57]
Data from Regulated Expression of a Tumor-Associated Antigen Reveals Multiple Levels of T-Cell Tolerance in a Mouse Model of Lung Cancer
Authors: Cheung Ann F. , DuPage Michel J.P. , Dong H. Katie , Chen Jianzhu , Jacks Tyler
Published: March 2024

Abstract
Maximizing the potential of cancer immunotherapy requires model systems that closely recapitulate human disease to study T-cell responses to tumor antigens and to test immunotherapeutic strategies. We have created a new system that is compatible with Cre-LoxP–regulatable mouse cancer models in which the SIY antigen is specifically overexpressed in tumors, mimicking clinically relevant TAAs. To show the utility of this system, we have characterized SIY-reactive T cells in the context of lung adenocarcinoma, revealing multiple levels of antigen-specific T-cell tolerance that serve to limit an effective antitumor response. Thymic deletion reduced the number of SIY-reactive T cells present in the animals. When potentially self-reactive T cells in the periphery were activated, they were efficiently eliminated. Inhibition of apoptosis resulted in more persistent self-reactive T cells, but these cells became anergic to antigen stimulation. Finally, in the presence of tumors overexpressing SIY, SIY-specific T cells required a higher level of costimulation to achieve functional activation. This system represents a valuable tool in which to explore sources contributing to T-cell tolerance of cancer and to test therapies aimed at overcoming this tolerance. [Cancer Res 2008;68(22):9459–68]
Data from Cellular Source and Amount of Vascular Endothelial Growth Factor and Platelet-Derived Growth Factor in Tumors Determine Response to Angiogenesis Inhibitors
Authors: Sennino Barbara , Kuhnert Frank , Tabruyn Sebastien P. , Mancuso Michael R. , Hu-Lowe Dana D. , Kuo Calvin J. , McDonald Donald M.
Published: March 2024

Abstract
Vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and their receptors are important targets in cancer therapy based on angiogenesis inhibition. However, it is unclear whether inhibition of VEGF and PDGF together is more effective than inhibition of either one alone. Here, we used two contrasting tumor models to compare the effects of inhibiting VEGF or PDGF alone, by adenovirally generated soluble receptors, to the effects of inhibiting both together. In RIP-Tag2 tumors, VEGF and PDGF inhibition together reduced tumor vascularity and abundance of pericytes. However, VEGF inhibition reduced tumor vascularity without decreasing pericyte density, and PDGF inhibition reduced pericytes without reducing tumor vascularity. By contrast, in Lewis lung carcinomas (LLC), inhibition of VEGF or PDGF reduced blood vessels and pericytes to the same extent as did inhibition of both together. Similar results were obtained using tyrosine kinase inhibitors AG-013736 and imatinib. In LLC, VEGF expression was largely restricted to pericytes and PDGF was largely restricted to endothelial cells, but, in RIP-Tag2 tumors, expression of both growth factors was more widespread and significantly greater than in LLC. These findings suggest that inhibition of PDGF in LLC reduced pericytes, and then tumor vessels regressed because pericytes were the main source of VEGF. The vasculature of RIP-Tag2 tumors, in which most VEGF is from tumor cells, was more resistant to PDGF inhibition. The findings emphasize the interdependence of pericytes and endothelial cells in tumors and the importance of tumor phenotype in determining the cellular effects of VEGF and PDGF inhibitors on tumor vessels. [Cancer Res 2009;69(10):4527–36]
Data from Bidirectional Crosstalk between Leptin and Insulin-like Growth Factor-I Signaling Promotes Invasion and Migration of Breast Cancer Cells via Transactivation of Epidermal Growth Factor Receptor
Authors: Saxena Neeraj K. , Taliaferro-Smith LaTonia , Knight Brandi B. , Merlin Didier , Anania Frank A. , O'Regan Ruth M. , Sharma Dipali
Published: March 2024

Abstract
Obesity is an independent risk factor for breast cancer, and obese breast cancer patients exhibit a higher risk for larger tumor burden and increased metastasis. Obesity, as associated with metabolic syndrome, results in an increase in circulating insulin-like growth factor (IGF), which acts as a mitogen. In addition, higher plasma level of adipocytokine leptin is associated with obesity. In the present study, we show that cotreatment with leptin and IGF-I significantly increases proliferation as well as invasion and migration of breast cancer cells. We found a novel bidirectional crosstalk between leptin and IGF-I signaling; IGF-I induced phosphorylation of leptin receptor (Ob-Rb) and leptin induced phosphorylation of IGF-I receptor (IGF-IR), whereas cotreatment induced synergistic phosphorylation and association of Ob-Rb and IGF-IR along with activation of downstream effectors, Akt and extracellular signal–regulated kinase. Leptin increased phosphorylation of IGF signaling molecules insulin-receptor substrate (IRS)-1 and IRS-2. Interestingly, we found that leptin and IGF-I cotreatment synergistically transactivated epidermal growth factor receptor (EGFR), depending on the proteolytic release of EGFR ligands, as the broad-spectrum matrix metalloproteinase inhibitor GM6001 could inhibit this effect. Using clinically relevant EGFR inhibitors, erlotinib and lapatinib, we found that inhibition of EGFR activation effectively inhibited leptin- and IGF-I–induced invasion and migration of breast cancer cells. Taken together, these data suggest a novel bidirectional crosstalk between leptin and IGF-I signaling that transactivates EGFR and promotes the metastatic properties as well as invasion and migration of breast cancer cells. Our findings indicate the possibility of using EGFR inhibitors erlotinib and lapatinib to counter the procancerous effects of leptin and IGF-I in breast cancers. [Cancer Res 2008;68(23):9712–22]
Data from Anterior Gradient 2 Is Expressed and Secreted during the Development of Pancreatic Cancer and Promotes Cancer Cell Survival
Authors: Ramachandran Vijaya , Arumugam Thiruvengadam , Wang Huamin , Logsdon Craig D.
Published: March 2024

Abstract
Pancreatic cancer is a major oncological challenge due to its aggressive growth and metastasis. In the current study, we investigated the role of anterior gradient 2 (AGR2) in these processes. AGR2 mRNA, as assessed by quantitative real-time reverse transcription–PCR (Q-RT-PCR), was 14-fold higher in pancreatic cancer compared with normal and pancreatitis tissues. Immunohistochemistry revealed high expression of AGR2 in neoplastic cells with 98% (56 of 57) positivity on pancreatic cancer and minimal staining in normal and pancreatitis tissues. AGR2 was also expressed in early pancreatic intraepithelial neoplastic lesions. RT-PCR and Western blotting showed elevated AGR2 expression in seven of nine pancreatic cancer cell lines. AGR2, as detected in conditioned media from cancer cells, indicated that it was secreted. The influence of AGR2 on pancreatic cancer cells was evaluated by silencing with small interfering RNA and short hairpin RNA. Silencing of AGR2 significantly reduced cell proliferation (MTS assay) and invasion (Boyden chamber assay) and improved gemcitabine sensitivity (fluorescence-activated cell sorting analysis). Conditioned media from cells in which AGR2 was silenced had a reduced ability to stimulate proliferation of pancreatic cancer cells, suggesting that secreted AGR2 was active. In vivo, silencing of AGR2 in MPanc-96 cells led to a significant reduction of tumor growth and increased the effectiveness of gemcitabine treatments in orthotopic tumor models evaluated by noninvasive bioluminescence imaging. In summary, AGR2 is expressed and secreted during pancreatic cancer development and plays an important role in cancer cell growth and survival. These observations suggest that AGR2 may be a useful molecular target in pancreatic cancer. [Cancer Res 2008;68(19):7811–8]
Data from The Melanoma-Associated Antigen A3 Mediates Fibronectin-Controlled Cancer Progression and Metastasis
Authors: Liu Wei , Cheng Sonia , Asa Sylvia L. , Ezzat Shereen
Published: March 2024

Abstract
Tumor cells frequently exhibit decreased adhesiveness due to failure to deposit stromal fibronectin (FN), permitting more rapid proliferation, migration, invasion, and metastasis. Although up-regulation of FN has been noted in gene profiles of carcinomas compared with normal tissue, reduced FN expression has been described at the peripheral margins of invading tumors. In this study, we investigate the role of FN in cancer behavior. Using human thyroid carcinoma cells with stably down-regulated FN, we performed gene profiling and created an orthotopic mouse model. We stably overexpressed the FN target, MAGE A3, which has also been identified as a target of the breast cancer risk factor fibroblast growth factor receptor 2, and examined the functional effects in vitro and in vivo in a flank model and an orthotopic model of thyroid cancer. Mouse xenografts showed significantly enhanced tumor growth as well as larger and more numerous lung metastases in response to FN silencing. Gene profiling identified the melanoma-associated antigen (MAGE A3) as significantly up-regulated in response to FN silencing. Forced expression of MAGE A3 resulted in p21 down-regulation, accelerated cell cycle progression, increased cell migration rate, and invasion in vitro and in vivo in an orthotopic mouse model where microcomputed tomography confirmed lung metastases that recapitulate the progression of human thyroid cancer. We conclude that MAGE A3 is a functional integrator of diverse signals, including FGFR2 and FN, to modulate cancer progression. [Cancer Res 2008;68(19):8104–12]
Data from Epithelial Phenotype Confers Resistance of Ovarian Cancer Cells to Oncolytic Adenoviruses
Authors: Strauss Robert , Sova Pavel , Liu Ying , Li Zong Yi , Tuve Sebastian , Pritchard David , Brinkkoetter Paul , Möller Thomas , Wildner Oliver , Pesonen Sari , Hemminki Akseli , Urban Nicole , Drescher Charles , Lieber André
Published: March 2024

Abstract
We studied the susceptibility of primary ovarian cancer cells to oncolytic adenoviruses. Using gene expression profiling of cancer cells either resistant or susceptible to viral oncolysis, we discovered that the epithelial phenotype of ovarian cancer represents a barrier to infection by commonly used oncolytic adenoviruses targeted to coxsackie-adenovirus receptor or CD46. Specifically, we found that these adenovirus receptors were trapped in tight junctions and not accessible for virus binding. Accessibility to viral receptors was critically linked to depolarization and the loss of tight and adherens junctions, both hallmarks of epithelial-to-mesenchymal transition (EMT). We showed that specific, thus far little-explored adenovirus serotypes (Ad3, Ad7, Ad11, and Ad14) that use receptor(s) other than coxsackie-adenovirus receptor and CD46 were able to trigger EMT in epithelial ovarian cancer cells and cause efficient oncolysis. Our studies on ovarian cancer cultures and xenografts also revealed several interesting cancer cell biology features. Tumors in situ as well as tumor xenografts in mice mostly contained epithelial cells and cells that were in a hybrid stage where they expressed both epithelial and mesenchymal markers (epithelial/mesenchymal cells). These epithelial/mesenchymal cells are the only xenograft-derived cells that can be cultured and with passaging undergo EMT and differentiate into mesenchymal cells. Our study provides a venue for improved virotherapy of cancer as well as new insights into cancer cell biology. [Cancer Res 2009;69(12):5115–25]
Data from Neuropilin-1 Upholds Dedifferentiation and Propagation Phenotypes of Renal Cell Carcinoma Cells by Activating Akt and Sonic Hedgehog Axes
Authors: Cao Ying , Wang Ling , Nandy Debashis , Zhang Ying , Basu Ananda , Radisky Derek , Mukhopadhyay Debabrata
Published: March 2024

Abstract
Expression of neuropilin-1 (NRP-1) has been shown in many cancer cells, but its molecular effect on tumorigenesis is largely unknown. In this report, we show that in aggressive types of renal cell carcinoma (RCC), NRP-1 is expressed at a high level. We show that after knockdown of NRP-1 by short hairpin RNA, RCC cells express significantly lower levels of MDM-2 and p63 proteins but higher levels of p53, and exhibit reduced migration and invasion. When implanted in mice, RCC cells with a reduced NRP-1 level have a statistically significant smaller tumor-forming ability than control cells. Also, NRP-1 knockdown RCC cells exhibit a more differentiated phenotype, as evidenced by the expression of epithelial-specific and kidney-specific cadherins, and the inhibition of sonic hedgehog expression participated in this effect. Inhibition of sonic hedgehog expression can be reversed by ΔNp63α overexpression. Our study reveals that NRP-1 helps maintain an undifferentiated phenotype in cancer cells. [Cancer Res 2008;68(21):8667–72]
Data from Cannabinoids Inhibit Glioma Cell Invasion by Down-regulating Matrix Metalloproteinase-2 Expression
Authors: Blázquez Cristina , Salazar María , Carracedo Arkaitz , Lorente Mar , Egia Ainara , González-Feria Luis , Haro Amador , Velasco Guillermo , Guzmán Manuel
Published: March 2024

Abstract
Cannabinoids, the active components of Cannabis sativa L. and their derivatives, inhibit tumor growth in laboratory animals by inducing apoptosis of tumor cells and impairing tumor angiogenesis. It has also been reported that these compounds inhibit tumor cell spreading, but the molecular targets of this cannabinoid action remain elusive. Here, we evaluated the effect of cannabinoids on matrix metalloproteinase (MMP) expression and its effect on tumor cell invasion. Local administration of Δ9-tetrahydrocannabinol (THC), the major active ingredient of cannabis, down-regulated MMP-2 expression in gliomas generated in mice, as determined by Western blot, immunofluorescence, and real-time quantitative PCR analyses. This cannabinoid-induced inhibition of MMP-2 expression in gliomas (a) was MMP-2–selective, as levels of other MMP family members were unaffected; (b) was mimicked by JWH-133, a CB2 cannabinoid receptor–selective agonist that is devoid of psychoactive side effects; (c) was abrogated by fumonisin B1, a selective inhibitor of ceramide biosynthesis; and (d) was also evident in two patients with recurrent glioblastoma multiforme. THC inhibited MMP-2 expression and cell invasion in cultured glioma cells. Manipulation of MMP-2 expression by RNA interference and cDNA overexpression experiments proved that down-regulation of this MMP plays a critical role in THC-mediated inhibition of cell invasion. Cannabinoid-induced inhibition of MMP-2 expression and cell invasion was prevented by blocking ceramide biosynthesis and by knocking-down the expression of the stress protein p8. As MMP-2 up-regulation is associated with high progression and poor prognosis of gliomas and many other tumors, MMP-2 down-regulation constitutes a new hallmark of cannabinoid antitumoral activity. [Cancer Res 2008;68(6):1945–52]
Data from Ionizing Radiation Induces Prostate Cancer Neuroendocrine Differentiation through Interplay of CREB and ATF2: Implications for Disease Progression
Authors: Deng Xuehong , Liu Han , Huang Jiaoti , Cheng Liang , Keller Evan T. , Parsons Sarah J. , Hu Chang-Deng
Published: March 2024

Abstract
Radiation therapy is a first-line treatment for prostate cancer patients with localized tumors. Although some patients respond well to the treatment, ∼10% of low-risk and up to 60% of high-risk prostate cancer patients experience recurrent tumors. However, the molecular mechanisms underlying tumor recurrence remain largely unknown. Here we show that fractionated ionizing radiation (IR) induces differentiation of LNCaP prostate cancer cells into neuroendocrine (NE)-like cells, which are known to be implicated in prostate cancer progression, androgen-independent growth, and poor prognosis. Further analyses revealed that two cyclic AMP–responsive element binding transcription factors, cyclic AMP–response element binding protein (CREB) and activating transcription factor 2 (ATF2), function as a transcriptional activator and a repressor, respectively, of NE-like differentiation and that IR induces NE-like differentiation by increasing the nuclear content of phospho-CREB and cytoplasmic accumulation of ATF2. Consistent with this notion, stable expression of a nonphosphorylatable CREB or a constitutively nuclear-localized ATF2 in LNCaP cells inhibits IR-induced NE-like differentiation. IR-induced NE-like morphologies are reversible, and three IR-resistant clones isolated from dedifferentiated cells have acquired the ability to proliferate and lost the NE-like cell properties. In addition, these three IR-resistant clones exhibit differential responses to IR- and androgen depletion–induced NE-like differentiation. However, they are all resistant to cell death induced by IR and the chemotherapeutic agent docetaxel and to androgen depletion–induced growth inhibition. These results suggest that radiation therapy–induced NE-like differentiation may represent a novel pathway by which prostate cancer cells survive the treatment and contribute to tumor recurrence. [Cancer Res 2008;68(23):9663–70]
Data from Imatinib Mesylate Induces Quiescence in Gastrointestinal Stromal Tumor Cells through the CDH1-SKP2-p27Kip1 Signaling Axis
Authors: Liu Ying , Perdreau Sophie A. , Chatterjee Payel , Wang Linan , Kuan Shih-Fan , Duensing Anette
Published: March 2024

Abstract
Gastrointestinal stromal tumors (GIST) are caused by activating mutations in the KIT or platelet-derived growth factor receptor α receptor tyrosine kinase genes. Approximately 85% of GIST patients treated with imatinib mesylate achieve disease stabilization, however, often in the presence of residual tumor masses. Complete remissions are rare and a substantial proportion of patients develop resistance to imatinib. Our study was designed to determine whether imatinib-associated responses may account for these clinical findings. We report here that imatinib stimulates cellular quiescence in a proportion of GIST cells as evidenced by up-regulation of the CDK inhibitor p27Kip1, loss of cyclin A, and reduced BrdUrd incorporation. Mechanistically, these events are associated with an imatinib-induced modulation of the APC/CDH1 signaling axis. Specifically, we provide evidence that imatinib down-regulates SKP2 and that this event is associated with increased nuclear CDH1, an activator of the APC that has been shown to regulate SKP2 stability. We also show that those GIST cells that do not undergo apoptosis in response to imatinib overexpress nuclear p27Kip1, indicating that they have withdrawn from the cell cycle and are quiescent. Lastly, we provide evidence that a fraction of primary GISTs with high SKP2 expression levels may have an increased risk of disease progression. Taken together, our results support a model in which GIST cells that do not respond to imatinib by apoptosis are removed from the proliferative pool by entering quiescence through modulation of the APC/CDH1-SKP2-p27Kip1 signaling axis. These results encourage further studies to explore compounds that modulate this pathway as antitumor agents in GISTs. [Cancer Res 2008;68(21):9015–23]
Data from Pleiotropic Biological Activities of Alternatively Spliced TMPRSS2/ERG Fusion Gene Transcripts
Authors: Wang Jianghua , Cai Yi , Yu Wendong , Ren Chengxi , Spencer David M. , Ittmann Michael
Published: March 2024

Abstract
TMPRSS2/ERG gene fusions are found in the majority of prostate cancers; however, there is significant heterogeneity in the 5′ region of the alternatively spliced fusion gene transcripts. We have found that there is also significant heterogeneity within the coding exons as well. There is variable inclusion of a 72-bp exon and other novel alternatively spliced isoforms. To assess the biological significance of these alternatively spliced transcripts, we expressed various transcripts in primary prostatic epithelial cells (PrEC) and in an immortalized PrEC line, PNT1a. The fusion gene transcripts promoted proliferation, invasion, and motility with variable activities that depended on the structure of the 5′ region encoding the TMPRSS2/ERG fusion and the presence of the 72-bp exon. Cotransfection of different isoforms further enhanced biological activity, mimicking the situation in vivo, in which multiple isoforms are expressed. Finally, knockdown of the fusion gene in VCaP cells resulted in inhibition of proliferation in vitro and tumor progression in an in vivo orthotopic mice model. Our results indicate that TMPRSS2/ERG fusion isoforms have variable biological activities promoting tumor initiation and progression and are consistent with our previous clinical observations indicating that certain TMPRSS2/ERG fusion isoforms are significantly correlated with more aggressive disease. [Cancer Res 2008;68(20):8516–24]
Data from Role of Acetylation and Extracellular Location of Heat Shock Protein 90α in Tumor Cell Invasion
Authors: Yang Yonghua , Rao Rehka , Shen Jie , Tang Yun , Fiskus Warren , Nechtman John , Atadja Peter , Bhalla Kapil
Published: March 2024

Abstract
Heat shock protein (hsp) 90 is an ATP-dependent molecular chaperone that maintains the active conformation of client oncoproteins in cancer cells. An isoform, hsp90α, promotes extracellular maturation of matrix metalloproteinase (MMP)-2, involved in tumor invasion and metastasis. Knockdown of histone deacetylase (HDAC) 6, which deacetylates lysine residues in hsp90, induces reversible hyperacetylation and attenuates ATP binding and chaperone function of hsp90. Here, using mass spectrometry, we identified seven lysine residues in hsp90α that are hyperacetylated after treatment of eukaryotic cells with a pan-HDAC inhibitor that also inhibits HDAC6. Depending on the specific lysine residue in the middle domain involved, although acetylation affects ATP, cochaperone, and client protein binding to hsp90α, acetylation of all seven lysines increased the binding of hsp90α to 17-allyl-amino-demethoxy geldanamycin. Notably, after treatment with the pan-HDAC inhibitor panobinostat (LBH589), the extracellular hsp90α was hyperacetylated and it bound to MMP-2, which was associated with increased in vitro tumor cell invasiveness. Treatment with antiacetylated hsp90α antibody inhibited in vitro invasion by tumor cells. Thus, reversible hyperacetylation modulates the intracellular and extracellular chaperone function of hsp90, and targeting extracellular hyperacetylated hsp90α may undermine tumor invasion and metastasis. [Cancer Res 2008;68(12):4833–42]
Data from CD151 Accelerates Breast Cancer by Regulating α6 Integrin Function, Signaling, and Molecular Organization
Authors: Yang Xiuwei H. , Richardson Andrea L. , Torres-Arzayus Maria I. , Zhou Pengcheng , Sharma Chandan , Kazarov Alexander R. , Andzelm Milena M. , Strominger Jack L. , Brown Myles , Hemler Martin E.
Published: March 2024

Abstract
CD151, a master regulator of laminin-binding integrins (α6β4, α6β1, and α3β1), assembles these integrins into complexes called tetraspanin-enriched microdomains. CD151 protein expression is elevated in 31% of human breast cancers and is even more elevated in high-grade (40%) and estrogen receptor–negative (45%) subtypes. The latter includes triple-negative (estrogen receptor, progesterone receptor, and HER2 negative) basal-like tumors. CD151 ablation markedly reduced basal-like mammary cell migration, invasion, spreading, and signaling (through FAK, Rac1, and lck) while disrupting epidermal growth factor receptor (EGFR)-α6 integrin collaboration. Underlying these defects, CD151 ablation redistributed α6β4 integrins subcellularly and severed molecular links between integrins and tetraspanin-enriched microdomains. In a prototypical basal-like mammary tumor line, CD151 ablation notably delayed tumor progression in ectopic and orthotopic xenograft models. These results (a) establish that CD151-α6 integrin complexes play a functional role in basal-like mammary tumor progression; (b) emphasize that α6 integrins function via CD151 linkage in the context of tetraspanin-enriched microdomains; and (c) point to potential relevance of CD151 as a high-priority therapeutic target, with relative selectivity (compared with laminin-binding integrins) for pathologic rather than normal physiology. [Cancer Res 2008;68(9):3204–13]
Data from Bicarbonate Increases Tumor pH and Inhibits Spontaneous Metastases
Authors: Robey Ian F. , Baggett Brenda K. , Kirkpatrick Nathaniel D. , Roe Denise J. , Dosescu Julie , Sloane Bonnie F. , Hashim Arig Ibrahim , Morse David L. , Raghunand Natarajan , Gatenby Robert A. , Gillies Robert J.
Published: March 2024

Abstract
The external pH of solid tumors is acidic as a consequence of increased metabolism of glucose and poor perfusion. Acid pH has been shown to stimulate tumor cell invasion and metastasis in vitro and in cells before tail vein injection in vivo. The present study investigates whether inhibition of this tumor acidity will reduce the incidence of in vivo metastases. Here, we show that oral NaHCO3 selectively increased the pH of tumors and reduced the formation of spontaneous metastases in mouse models of metastatic breast cancer. This treatment regimen was shown to significantly increase the extracellular pH, but not the intracellular pH, of tumors by 31P magnetic resonance spectroscopy and the export of acid from growing tumors by fluorescence microscopy of tumors grown in window chambers. NaHCO3 therapy also reduced the rate of lymph node involvement, yet did not affect the levels of circulating tumor cells, suggesting that reduced organ metastases were not due to increased intravasation. In contrast, NaHCO3 therapy significantly reduced the formation of hepatic metastases following intrasplenic injection, suggesting that it did inhibit extravasation and colonization. In tail vein injections of alternative cancer models, bicarbonate had mixed results, inhibiting the formation of metastases from PC3M prostate cancer cells, but not those of B16 melanoma. Although the mechanism of this therapy is not known with certainty, low pH was shown to increase the release of active cathepsin B, an important matrix remodeling protease. [Cancer Res 2009;69(6):2260–8]
Data from Cytoglobin, the Newest Member of the Globin Family, Functions as a Tumor Suppressor Gene
Authors: Shivapurkar Narayan , Stastny Victor , Okumura Naoki , Girard Luc , Xie Yang , Prinsen Clemens , Thunnissen Frederik B. , Wistuba Ignacio I. , Czerniak Bogdan , Frenkel Eugene , Roth Jack A. , Liloglou Triantafillos , Xinarianos George , Field John K. , Minna John D. , Gazdar Adi F.
Published: March 2024

Abstract
Cytoglobin (CYGB) is a recently discovered vertebrate globin distantly related to myoglobin with unknown function. CYGB is assigned to chromosomal region 17q25, which is frequently lost in multiple malignancies. Previous studies failed to detect evidence for mutations in the CYGB gene. Recent studies provided preliminary evidence for increased methylation of the gene in lung cancer. Our study was aimed at investigating the role of CYGB as a tumor suppressor gene. By nested methylation-specific DNA sequencing analysis of lung and breast cancer cell lines and bronchial and mammary epithelial cell lines, we identified that methylation of a 110-bp CpG-rich segment of the CYGB promoter was correlated with gene silencing. We specifically targeted this sequence and developed a quantitative methylation-specific PCR assay, suitable for high-throughput analysis. We showed that the tumor specificity of CYGB methylation in discriminating patients with and without lung cancer, using biopsies and sputum samples. We further showed the tumor specificity of this assay with multiple other epithelial and hematologic malignancies. To show tumor suppressor activity of CYGB, we performed the following: (a) RNA interference–mediated knockdown of CYGB gene on colony formation in a CYGB expression–positive lung cancer cell line, resulting in increased colony formation; (b) enforced gene expression in CYGB expression–negative lung and breast cancer cell lines, reducing colony formation; and (c) identification of potential proximate targets down-stream of the CYGB genes. Our data constitute the first direct functional evidence for CYGB, the newest member of the globin family, as a tumor suppressor gene. [Cancer Res 2008;68(18):7448–56]
Data from Sequence Variants at 22q13 Are Associated with Prostate Cancer Risk
Authors: Sun Jielin , Zheng Siqun Lilly , Wiklund Fredrik , Isaacs Sarah D. , Li Ge , Wiley Kathleen E. , Kim Seong-Tae , Zhu Yi , Zhang Zheng , Hsu Fang-Chi , Turner Aubrey R. , Stattin Pär , Liu Wennuan , Kim Jin Woo , Duggan David , Carpten John , Isaacs William , Grönberg Henrik , Xu Jianfeng , Chang Bao-Li
Published: March 2024

Abstract
To search for genetic variants that are associated with prostate cancer risk in the genome, we combined the data from our genome-wide association study (GWAS) in a population-based case-control study in Sweden with publicly available GWAS data from the Cancer Genetic Markers of Susceptibility (CGEMS) study. We limited the cases to those with aggressive disease in an attempt to identify risk variants that are associated with this most clinically relevant form of the disease. Among the most likely candidate single nucleotide polymorphisms (SNP) identified from the two GWAS, we sequentially confirmed one SNP at 22q13 in two independent study populations: the remaining subjects in Cancer of the Prostate in Sweden and a hospital-based case-control study at Johns Hopkins Hospital. Association of aggressive prostate cancer with the SNP at 22q13 was also observed in the publicly available data of four additional study populations from the second stage of the CGEMS study. In all seven study populations examined, the frequency of allele “C” of rs9623117 at 22q13 was consistently higher in aggressive cases than in controls. The combined allelic test was highly significant, with P = 5.0 × 10−7. The odds ratio (OR) of allele C for aggressive prostate cancer was estimated to be 1.18 [95% confidence interval (95% CI), 1.11-1.26]. However, the SNP was also associated with nonaggressive prostate cancer, with an estimated OR of 1.11 (95% CI, 1.04-1.19; P = 0.004). The risk-associated variants are located within the genomic region of TNRC6B, a gene involved in miRNA-mediated mRNA degradation. Additional studies are warranted to further confirm the association. [Cancer Res 2009;69(1):10–5]
Data from Novel Designs of Multivalent Anti-CD20 Humanized Antibodies as Improved Lymphoma Therapeutics
Authors: Rossi Edmund A. , Goldenberg David M. , Cardillo Thomas M. , Stein Rhona , Wang Yang , Chang Chien-Hsing
Published: March 2024

Abstract
Multivalent antibodies, either monospecific or bispecific, may improve the efficacy of current therapeutic interventions involving a single monoclonal antibody (mAb). We have applied the Dock-and-Lock (DNL) method, a new platform technology for the site-specific and covalent assembly of modular components into stably tethered complexes of defined composition, to prepare a hexavalent, anti-CD20 antibody, designated Hex-hA20, which comprises six Fabs with one Fc. We show that Hex-hA20 retains the binding activity of all six Fabs, associates with CD20 in lipid rafts, affects antibody-dependent cell-mediated cytotoxicity, but not complement-dependent cytotoxicity, and inhibits proliferation of Daudi, Raji, and Ramos cells in vitro at subnanomolar concentrations without the need for a cross-linking antibody. In addition, Hex-hA20 induces strong homotypical adhesion and is inefficient in stimulating calcium mobilization. Thus, Hex-hA20 exhibits biological properties attributable to both type I and type II anti-CD20 mAbs, as exemplified by rituximab and tositumomab, respectively. Although Hex-hA20 has a short serum half-life, it shows antitumor efficacy in tumor-bearing mice comparable with veltuzumab at equivalent doses. The versatile DNL method was also applied to generate two other multivalent anti-CD20 antibodies without the Fc region, Tri-hA20 and Tetra-hA20, comprising three and four Fabs of veltuzumab, respectively. Similar to Hex-hA20, these were purified to near homogeneity and shown to have potent antiproliferative activity in vitro, thus indicating the need for clustering three or more CD20 molecules on the cell surface to induce growth inhibition. [Cancer Res 2008;68(20):8384–92]
Data from Hepatocyte Growth Factor Induces Gefitinib Resistance of Lung Adenocarcinoma with Epidermal Growth Factor Receptor–Activating Mutations
Authors: Yano Seiji , Wang Wei , Li Qi , Matsumoto Kunio , Sakurama Haruko , Nakamura Takahiro , Ogino Hirokazu , Kakiuchi Soji , Hanibuchi Masaki , Nishioka Yasuhiko , Uehara Hisanori , Mitsudomi Tetsuya , Yatabe Yasushi , Nakamura Toshikazu , Sone Saburo
Published: March 2024

Abstract
Lung cancer with epidermal growth factor receptor (EGFR)–activating mutations responds favorably to the EGFR tyrosine kinase inhibitors gefitinib and erlotinib. However, 25% to 30% of patients with EGFR-activating mutations show intrinsic resistance, and the responders invariably acquire resistance to gefitinib. Here, we showed that hepatocyte growth factor (HGF), a ligand of MET oncoprotein, induces gefitinib resistance of lung adenocarcinoma cells with EGFR-activating mutations by restoring the phosphatidylinositol 3-kinase/Akt signaling pathway via phosphorylation of MET, but not EGFR or ErbB3. Strong immunoreactivity for HGF in cancer cells was detected in lung adenocarcinoma patients harboring EGFR-activating mutations, but no T790M mutation or MET amplification, who showed intrinsic or acquired resistance to gefitinib. The findings indicate that HGF-mediated MET activation is a novel mechanism of gefitinib resistance in lung adenocarcinoma with EGFR-activating mutations. Therefore, inhibition of HGF-MET signaling may be a considerable strategy for more successful treatment with gefitinib. [Cancer Res 2008;68(22):9479–87]
Data from Antitumor Activity and Pharmacology of a Selective Focal Adhesion Kinase Inhibitor, PF-562,271
Authors: Roberts Walter Gregory , Ung Ethan , Whalen Pamela , Cooper Beth , Hulford Catherine , Autry Christofer , Richter Daniel , Emerson Earling , Lin Jing , Kath John , Coleman Kevin , Yao Lili , Martinez-Alsina Luis , Lorenzen Marianne , Berliner Martin , Luzzio Michael , Patel Nandini , Schmitt Erika , LaGreca Susan , Jani Jitesh , Wessel Matt , Marr Eric , Griffor Matt , Vajdos Felix
Published: March 2024

Abstract
Cancer cells are characterized by the ability to grow in an anchorage-independent manner. The activity of the nonreceptor tyrosine kinase, focal adhesion kinase (FAK), is thought to contribute to this phenotype. FAK localizes in focal adhesion plaques and has a role as a scaffolding and signaling protein for other adhesion molecules. Recent studies show a strong correlation between increased FAK expression and phosphorylation status and the invasive phenotype of aggressive human tumors. PF-562,271 is a potent, ATP-competitive, reversible inhibitor of FAK and Pyk2 catalytic activity with a IC50 of 1.5 and 14 nmol/L, respectively. Additionally, PF-562,271 displayed robust inhibition in an inducible cell-based assay measuring phospho-FAK with an IC50 of 5 nmol/L. PF-562,271 was evaluated against multiple kinases and displays >100× selectivity against a long list of nontarget kinases. PF-562,271 inhibits FAK phosphorylation in vivo in a dose-dependent fashion (calculated EC50 of 93 ng/mL, total) after p.o. administration to tumor-bearing mice. In vivo inhibition of FAK phosphorylation (>50%) was sustained for >4 hours with a single p.o. dose of 33 mg/kg. Antitumor efficacy and regressions were observed in multiple human s.c. xenograft models. No weight loss, morbidity, or mortality were observed in any in vivo experiment. Tumor growth inhibition was dose and drug exposure dependent. Taken together, these data show that kinase inhibition with an ATP-competitive small molecule inhibitor of FAK decreases the phospho-status in vivo, resulting in robust antitumor activity. [Cancer Res 2008;68(6):1935–44]