bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Loss of Rad51c Leads to Embryonic Lethality and Modulation of Trp53-Dependent Tumorigenesis in Mice
Authors: Kuznetsov Sergey G. , Haines Diana C. , Martin Betty K. , Sharan Shyam K.
Published: March 2024

Abstract
RecA/Rad51 protein family members (Rad51, Rad51b, Rad51c, Rad51d, Xrcc2, and Xrcc3) are essential for DNA repair by homologous recombination, and their role in cancers has been anticipated. Here we provide the first direct evidence for a tumor suppressor function for a member of the Rad51 family. We show that Rad51c deficiency leads to early embryonic lethality, which can be delayed on a Trp53-null background. To uncover the role of Rad51c in tumorigenesis, we have exploited the fact that Rad51c and Trp53 are both closely located on the mouse chromosome 11. We have generated double heterozygous (DH) mice carrying mutant alleles of both genes either on different (DH-trans) or on the same chromosome (DH-cis), the latter allowing for a deletion of wild-type alleles of both genes by loss of heterozygosity. DH-trans mice, in contrast to DH-cis, developed tumors with latency and spectrum similar to Trp53 heterozygous mice. Strikingly, Rad51c mutation in DH-cis mice promoted the development of tumors of specialized sebaceous glands and suppressed tumors characteristic of Trp53 mutation. In addition, DH-cis females developed tumors significantly earlier than any other group. [Cancer Res 2009;69(3):863–72]
Data from Simultaneous Infiltration of Polyfunctional Effector and Suppressor T Cells into Renal Cell Carcinomas
Authors: Attig Sebastian , Hennenlotter Jörg , Pawelec Graham , Klein Gerd , Koch Sven D. , Pircher Hanspeter , Feyerabend Susan , Wernet Dorothee , Stenzl Arnulf , Rammensee Hans-Georg , Gouttefangeas Cécile
Published: March 2024

Abstract
Renal cell carcinoma is frequently infiltrated by cells of the immune system. This makes it important to understand interactions between cancer cells and immune cells so they can be manipulated to bring clinical benefit. Here, we analyze subsets and functions of T lymphocytes infiltrating renal cell tumors directly ex vivo following mechanical disaggregation and without any culture step. Subpopulations of memory and effector CD4+ Th1, Th2, and Th17 and CD8+ Tc1 cells were identified based on surface phenotype, activation potential, and multicytokine production. Compared with the same patient's peripheral blood, T lymphocytes present inside tumors were found to be enriched in functional CD4+ cells of the Th1 lineage and in effector memory CD8+ cells. Additionally, several populations of CD4+ and CD8+ regulatory T cells were identified that may synergize to locally dampen antitumor T-cell responses. [Cancer Res 2009;69(21):8412–9]
Data from Quantitative Phosphoproteomics Reveals a Cluster of Tyrosine Kinases That Mediates Src Invasive Activity in Advanced Colon Carcinoma Cells
Authors: Leroy Cédric , Fialin Camille , Sirvent Audrey , Simon Valérie , Urbach Serge , Poncet Joël , Robert Bruno , Jouin Patrick , Roche Serge
Published: March 2024

Abstract
The nonreceptor tyrosine kinase Src is frequently overexpressed and/or activated in human colorectal carcinoma (CRC), and its increased activity has been associated with a poor clinical outcome. Src has been implicated in growth and invasion of these cancer cells by still not well-known mechanisms. Here, we addressed Src oncogenic signaling using quantitative phosphoproteomics. Src overexpression increased growth and invasiveness of metastatic SW620 CRC cells. Stable isotope labeling with amino acids in cell culture in combination with liquid chromatography tandem mass spectrometry allowed the identification of 136 proteins which exhibited a significant increase in and/or association with tyrosine phosphorylation upon Src expression. These mainly include signaling, cytoskeleton, and vesicular-associated proteins. Interestingly, Src also phosphorylated a cluster of tyrosine kinases, i.e., the receptors Met and EphA2, the cytoplasmic tyrosine kinase Fak, and pseudo-tyrosine kinase SgK223, which were required for its invasive activity. Similar results were obtained with metastatic Colo205 CRC cells that exhibit high endogenous Src activity. We concluded that Src uses a tyrosine kinases network to promote its invasive activity in CRC and this implicates a reverse signaling via tyrosine kinase receptors. Targeting these tyrosine kinases may be of significant therapeutic value in this cancer. [Cancer Res 2009;69(6):2279–86]
Data from Fibroblast Hepatocyte Growth Factor Promotes Invasion of Human Mammary Ductal Carcinoma In situ
Authors: Jedeszko Christopher , Victor Bernadette C. , Podgorski Izabela , Sloane Bonnie F.
Published: March 2024

Abstract
Stromal-derived hepatocyte growth factor (HGF) acting through its specific proto-oncogene receptor c-Met has been suggested to play a paracrine role in the regulation of tumor cell migration and invasion. The transition from preinvasive ductal carcinoma in situ (DCIS) to invasive breast carcinoma is marked by infiltration of stromal fibroblasts and the loss of basement membrane. We hypothesized that HGF produced by the infiltrating fibroblasts may alter proteolytic pathways in DCIS cells, and, to study this hypothesis, established three-dimensional reconstituted basement membrane overlay cocultures with two human DCIS cell lines, MCF10.DCIS and SUM102. Both cell lines formed large dysplastic structures in three-dimensional cultures that resembled DCIS in vivo and occasionally developed invasive outgrowths. In coculture with HGF-secreting mammary fibroblasts, the percentage of DCIS structures with invasive outgrowths was increased. Activation of c-Met with conditioned medium from HGF-secreting fibroblasts or with recombinant HGF increased the percentage of DCIS structures with invasive outgrowths, their degradation of collagen IV, and their secretion of urokinase-type plasminogen activator and its receptor. In agreement with the in vitro findings, coinjection with HGF-secreting fibroblasts increased invasiveness of MCF10.DCIS xenografts in severe combined immunodeficient mice. Our study shows that paracrine HGF/c-Met signaling between fibroblasts and preinvasive DCIS cells enhances the transition to invasive carcinomas and suggests that three-dimensional cocultures are appropriate models for testing therapeutics that target tumor microenvironment-enhanced invasiveness. [Cancer Res 2009;69(23):9148–55]
Data from Introducing Nanochemoprevention as a Novel Approach for Cancer Control: Proof of Principle with Green Tea Polyphenol Epigallocatechin-3-Gallate
Authors: Siddiqui Imtiaz A. , Adhami Vaqar M. , Bharali Dhruba J. , Hafeez Bilal B. , Asim Mohammad , Khwaja Sabih I. , Ahmad Nihal , Cui Huadong , Mousa Shaker A. , Mukhtar Hasan
Published: March 2024

Abstract
Chemoprevention, especially through the use of naturally occurring phytochemicals capable of impeding the process of one or more steps of carcinogenesis process, is a promising approach for cancer management. Despite promising results in preclinical settings, its applicability to humans has met with limited success largely due to inefficient systemic delivery and bioavailability of promising chemopreventive agents. Here, we introduce the concept of nanochemoprevention, which uses nanotechnology for enhancing the outcome of chemoprevention. We encapsulated green tea polyphenol epigallocatechin-3-gallate (EGCG) in polylactic acid–polyethylene glycol nanoparticles and observed that encapsulated EGCG retains its biological effectiveness with over 10-fold dose advantage for exerting its proapoptotic and angiogenesis inhibitory effects, critically important determinants of chemopreventive effects of EGCG in both in vitro and in vivo systems. Thus, this study could serve as a basis for the use of nanoparticle-mediated delivery to enhance bioavailability and limit any unwanted toxicity of chemopreventive agents, such as EGCG. [Cancer Res 2009;69(5):1712–6]
Data from Inhibition of Constitutively Activated Nuclear Factor-κB Induces Reactive Oxygen Species- and Iron-Dependent Cell Death in Cutaneous T-Cell Lymphoma
Authors: Kiessling Michael K. , Klemke Claus D. , Kamiński Marcin M. , Galani Ioanna E. , Krammer Peter H. , Gülow Karsten
Published: March 2024

Abstract
Aberrant signaling of the nuclear facotr (NF-κB) pathway has been identified as a mediator of survival and apoptosis resistance in leukemias and lymphomas. Here, we report that cell death of cutaneous T-cell lymphoma cell lines induced by inhibition of the NF-κB pathway is independent of caspases or classic death receptors. We found that free intracellular iron and reactive oxygen species (ROS) are the main mediators of this cell death. Antioxidants such as N-Acetyl-l-cysteine and glutathione or the iron chelator desferrioxamine effectively block cell death in cutaneous T-cell lymphoma cell lines or primary T cells from Sézary patients. We show that inhibition of constitutively active NF-κB causes down-regulation of ferritin heavy chain (FHC) that leads to an increase of free intracellular iron, which, in turn, induces massive generation of ROS. Furthermore, direct down-regulation of FHC by siRNA caused a ROS-dependent cell death. Finally, high concentrations of ROS induce cell death of malignant T cells. In contrast, T cells isolated from healthy donors do not display down-regulation of FHC and, therefore, do not show an increase in iron and cell death upon NF-κB inhibition. In addition, in a murine T-cell lymphoma model, we show that inhibition of NF-κB and subsequent down-regulation of FHC significantly delays tumor growth in vivo. Thus, our results promote FHC as a potential target for effective therapy in lymphomas with aberrant NF-κB signaling. [Cancer Res 2009;69(6):2365–74]
Data from Cyclic AMP Signaling as a Mediator of Vasculogenic Mimicry in Aggressive Human Melanoma Cells In vitro
Authors: Lissitzky Jean-Claude , Parriaux Danielle , Ristorcelli Elodie , Vérine Alain , Lombardo Dominique , Verrando Patrick
Published: March 2024

Abstract
Aggressive melanoma cells can engage in a process termed vasculogenic mimicry (VM) that reflects the ability of tumor cells to express a multipotent, stem cell–like phenotype. Melanoma cell plasticity contributes to the lack of efficient therapeutic strategies targeting metastatic tumors. This study reveals cyclic AMP as a mediator of VM in vitro. In uveal and cutaneous metastatic aggressive human melanoma cells, an increase in cyclic AMP by forskolin, dibutyryl cyclic AMP, or G protein–coupled receptor (GPCR) ligands such as adrenaline and vasoactive intestinal peptide inhibited VM to different extents. Although chemical modulators of protein kinase A (PKA) had no effect, a specific pharmacologic activator of Exchange protein directly activated by cyclic AMP (Epac) impaired VM. Ras-associated protein-1 (Rap1) activation assays revealed that cyclic AMP–elevating agents induce a PKA-independent activation of Epac/Rap1. Pharmacologic inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activity abolished VM. Phosphorylation of ERK1/2 was PKA-independently inhibited by forskolin but not inhibited by Epac/Rap1 signaling, PKA modulation, or GPCR ligands. Furthermore, the forskolin also inhibited phosphatidyl inositol-3-kinase (PI3K)-mediated activation of protein kinase Akt, as monitored by Ser473 phosphorylation. The pharmacologic activation of Epac and GPCR ligands slightly stimulated Akt, a likely concomitant process of VM modulation. Collectively, these data show that forskolin strongly inhibits VM through PKA-independent activation of Epac/Rap1, PKA-, and Epac-independent inactivation of ERK1/2 and inhibition of PI3K/Akt. The data also show that VM inhibition by GPCR ligands involves mainly the Epac/Rap1-activated signal. Thus cyclic AMP inhibits VM through multiple signaling pathways. [Cancer Res 2009;69(3):802–9]
Data from Adiponectin-Activated AMPK Stimulates Dephosphorylation of AKT through Protein Phosphatase 2A Activation
Authors: Kim Kun-yong , Baek Ahmi , Hwang Ji-Eun , Choi Yeon A. , Jeong Joon , Lee Myeong-Sok , Cho Dea Ho , Lim Jong-Seok , Kim Keun Il , Yang Young
Published: March 2024

Abstract
Low serum levels of adiponectin are a high risk factor for various types of cancer. Although adiponectin inhibits proliferation and metastasis of breast cancer cells, the underlying molecular mechanisms remain obscure. In this study, we show that adiponectin-activated AMPK reduces the invasiveness of MDA-MB-231 cells by stimulating dephosphorylation of AKT by increasing protein phosphatase 2A (PP2A) activity. Among the various regulatory B56 subunits, B56γ was directly phosphorylated by AMPK at Ser298 and Ser336, leading to an increase of PP2A activity through dephosphorylation of PP2Ac at Tyr307. We also show that both the blood levels of adiponectin and the tissue levels of PP2A activity were decreased in breast cancer patients and that the direct administration of adiponectin into tumor tissues stimulates PP2A activity. Taken together, these findings show that adiponectin, derived from adipocytes, negatively regulates the invasiveness of breast cancer cells by activating the tumor suppressor PP2A. [Cancer Res 2009;69(9):4018–26]
Data from Inhibition of Peroxisome Proliferator-Activated Receptor γ Increases Estrogen Receptor–Dependent Tumor Specification
Authors: Yin Yuzhi , Yuan Hongyan , Zeng Xiao , Kopelovich Levy , Glazer Robert I.
Published: March 2024

Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that regulates gene transcription associated with intermediary metabolism, adipocyte differentiation, and tumor suppression and proliferation. To understand the role of PPARγ in tumorigenesis, transgenic mice were generated with mammary gland–directed expression of the dominant-negative transgene Pax8PPARγ. Transgenic mice were phenotypically indistinguishable from wild-type (WT) mice, but mammary epithelial cells expressed a greater percentage of CD29hi/CD24neg, CK5+, and double-positive CK14/CK18 cells. These changes correlated with reduced PTEN and increased Ras and extracellular signal-regulated kinase (ERK) and AKT activation. Although spontaneous tumorigenesis did not occur, transgenic animals were highly susceptible to progestin/7,12-dimethylbenz(a)anthracene–induced mammary carcinogenesis, which in contrast to WT mice resulted in a high tumor multiplicity and, most importantly, in the appearance of predominantly estrogen receptor α–positive (ER+) ductal adenocarcinomas. Tumors expressed a similar PTENlo/pERKhi/pAKThi phenotype as mammary epithelium and exhibited high activation of estrogen response element–dependent reporter gene activity. Tumorigenesis in MMTV-Pax8PPARγ mice was insensitive to the chemopreventive effect of a PPARγ agonist but was profoundly inhibited by the ER antagonist fulvestrant. These results reveal important new insights into the previously unrecognized role of PPARγ in the specification of mammary lineage and the development of ER+ tumors. [Cancer Res 2009;69(2):687–94]
Data from E2F1 Expression Is Deregulated and Plays an Oncogenic Role in Sporadic Burkitt's Lymphoma
Authors: Molina-Privado Irene , Rodríguez-Martínez María , Rebollo Patricia , Martín-Pérez Daniel , Artiga María-Jesús , Menárguez Javier , Flemington Erik K. , Piris Miguel A. , Campanero Miguel R.
Published: March 2024

Abstract
Current treatments of sporadic Burkitt's lymphoma (sBL) are associated with severe toxicities. A better understanding of sBL formation would facilitate development of less toxic therapies. The etiology of sBL remains, however, largely unknown, C-MYC up-regulation being the only lesion known to occur in all sBL cases. Several studies examining the role of C-MYC in the pathogenesis of BL have concluded that C-MYC translocation is not the only critical event and that additional unidentified factors are expected to be involved in the formation of this tumor. We herein report that a gene distinct from C-MYC, E2F1, is involved in the formation of all or most sBL tumors. We found that E2F1 is highly expressed in Burkitt's lymphoma cell lines and sBL lymphoma specimens. Our data indicate that its elevated expression is not merely the consequence of the presence of more cycling cells in this tumor relative to other cell lines or to other neoplasias. In fact, we show that reduction of its expression in sBL cells inhibits tumor formation and decreases their proliferation rate. We also provide data suggesting that E2F1 collaborates with C-MYC in sBL formation. E2F1 expression down-regulation did not affect, however, the proliferation of human primary diploid fibroblasts. Because E2F1 is not needed for cell proliferation of normal cells, our results reveal E2F1 as a promising therapeutic target for sBL. [Cancer Res 2009;69(9):4052–8]
Data from Development of a Multiplex Quantitative PCR Signature to Predict Progression in Non–Muscle-Invasive Bladder Cancer
Authors: Wang Rou , Morris David S. , Tomlins Scott A. , Lonigro Robert J. , Tsodikov Alexander , Mehra Rohit , Giordano Thomas J. , Kunju L. Priya , Lee Cheryl T. , Weizer Alon Z. , Chinnaiyan Arul M.
Published: March 2024

Abstract
In bladder cancer, clinical grade and stage fail to capture outcome. We developed a clinically applicable quantitative PCR (QPCR) gene signature to predict progression in non–muscle-invasive bladder cancer. Comparative metaprofiling of 12 DNA microarray data sets (comprising 631 samples and 241,298 probe sets) identified 96 genes, which showed differential expression in seven clinical outcome categories, or were identified as outliers, historic markers, or housekeeping genes. QPCR was done to determine mRNA expression from 96 bladder tumors. Fifty-seven genes differentiated T2 from non-T2 tumors (P < 0.05). Principal components analysis and Cox regression models were used to predict probability of T2 progression for non-T2 patients, placing them into high- and low-risk groups based on their gene expression. At 2 years, high-risk patients exhibited greater T2 progression (45% for high-risk patients versus 12% for low-risk patients; P = 0.003, log-rank test). This difference remained significant within T1 tumors (61% for high-risk patients versus 22% for low-risk patients; P = 0.02) and Ta tumors (29% for high-risk patients versus 0% for low-risk patients; P = 0.03). The best multivariate Cox model included stage and gender, and this signature provided predictive improvement over both (P = 0.002, likelihood ratio test). Immunohistochemistry was done for two genes in the signature not previously described in bladder cancer, ACTN1 and CDC25B, corroborating their up-regulation at the protein level with disease progression. Thus, we identified a 57-gene QPCR panel to help predict progression of non–muscle-invasive bladder cancers and delineate a systematic, generalizable approach to converting microarray data into a multiplex assay for cancer progression. [Cancer Res 2009;69(9):3810–8]
Data from Anticancer Chemotherapy Inhibits MHC Class I–Related Chain A Ectodomain Shedding by Downregulating ADAM10 Expression in Hepatocellular Carcinoma
Authors: Kohga Keisuke , Takehara Tetsuo , Tatsumi Tomohide , Miyagi Takuya , Ishida Hisashi , Ohkawa Kazuyoshi , Kanto Tatsuya , Hiramatsu Naoki , Hayashi Norio
Published: March 2024

Abstract
MHC class I–related chain A (MICA) is a ligand for the NKG2D-activating immunoreceptor that mediates activation of natural killer (NK) cells. The ectodomain of MICA is shed from tumor cells, which may be an important means of evading antitumor immunity. We previously reported that patients with hepatocellular carcinoma (HCC) display high levels of soluble MICA in circulation, which could be downregulated by chemotherapy. The present study shows that anti-HCC drugs suppress MICA ectodomain shedding by inhibiting expression of a disintegrin and metalloproteinase 10 (ADAM10). Both ADAM10 and CD44, a typical substrate of the ADAM10 protease, were expressed in human HCC tissues and HCC cells but not in normal liver tissues or cultured hepatocytes. Small interfering RNA–mediated knockdown experiments revealed that ADAM10 is a critical sheddase for both MICA and CD44 in HCC cells. Of interest is the finding that epirubicin clearly downregulated ADAM10 expression and MICA shedding in HCC cells; its suppressive effect on MICA shedding was abolished in ADAM10-depleted cells. Epirubicin treatment also enhanced the NKG2D-mediated NK sensitivity of HCC cells. Patients with HCC had significantly higher levels of serum-soluble CD44, which correlated well with serum-soluble MICA levels, thus suggesting a close link between ADAM10 activity and MICA shedding in these patients. Soluble MICA and CD44 levels were downregulated with a significant correlation in patients treated by transarterial chemoembolization using epirubicin. In conclusion, anticancer drugs can modulate expression of ADAM10, which is critically involved in MICA ectodomain shedding. Epirubicin therapy may have a previously unrecognized effect on antitumor immunity in HCC patients. [Cancer Res 2009;69(20):8050–7]
Data from Effective Immunotherapy against Murine Gliomas Using Type 1 Polarizing Dendritic Cells—Significant Roles of CXCL10
Authors: Fujita Mitsugu , Zhu Xinmei , Ueda Ryo , Sasaki Kotaro , Kohanbash Gary , Kastenhuber Edward R. , McDonald Heather A. , Gibson Gregory A. , Watkins Simon C. , Muthuswamy Ravikumar , Kalinski Pawel , Okada Hideho
Published: March 2024

Abstract
In an attempt to develop effective vaccines against central nervous system (CNS) tumors, we evaluated the ability of vaccines with standard dendritic cells (DC) versus type 1 polarizing DCs (DC1) to induce glioma-specific type 1 CTLs with CNS tumor-relevant homing properties and the mechanism of their action. C57BL/6 mouse–derived bone marrow cells were cultured with mouse granulocyte/macrophage colony-stimulating factor (GM-CSF) for 6 days, and CD11c+ cells were subsequently cultured with GM-CSF, rmIFN-γ, rmIFN-α, rmIL-4, and polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose for 24 hours to generate DC1s. In analogy to their human counterparts, mouse DC1s exhibited surface marker profiles of mature DCs and produced high levels of IL-12 and CXCL10. Importantly for their application as cancer vaccines, such DC1s stably retained their type 1 phenotype even when exposed to type 2–promoting or regulatory T cell (Treg)–promoting environments. Consistently, mouse DC1s induced antigen-specific type 1 CTLs more efficiently than nonpolarized DCs in vitro. DC1s given s.c. migrated into draining lymph nodes, induced antigen-specific CTLs, and suppressed Treg accumulation. In addition, s.c. immunization with DC1s loaded with glioma-associated antigen (GAA)–derived CTL epitope peptides prolonged the survival of CNS GL261 glioma-bearing mice, which was associated with efficient CNS glioma homing of antigen-specific CTLs. Intratumoral injections of GAA peptide-loaded DC1s further enhanced the anti-CNS glioma effects of DC1-based s.c. immunization. Interestingly, the antitumor functions were abrogated with CXCL10−/− mouse–derived DC1s. Collectively, these findings show the anti-CNS glioma effects of DC1-based therapy and a novel role of CXCL10 in the immunologic and therapeutic activity of DC-based cancer vaccines. [Cancer Res 2009;69(4):1587–95]
Data from Specific Cross-talk between Epidermal Growth Factor Receptor and Integrin αvβ5 Promotes Carcinoma Cell Invasion and Metastasis
Authors: Ricono Jill M. , Huang Miller , Barnes Leo A. , Lau Steven K. , Weis Sara M. , Schlaepfer David D. , Hanks Steven K. , Cheresh David A.
Published: March 2024

Abstract
Tyrosine kinase receptors and integrins play essential roles in tumor cell invasion and metastasis. Previously, we showed that epidermal growth factor (EGF) stimulation of pancreatic carcinoma cells led to invasion and metastasis that was blocked by antagonists of integrin αvβ5. Here, we show that EGF stimulates metastasis of carcinoma cells via a Src-dependent phosphorylation of p130 CAS leading to activation of Rap1, a small GTPase involved in integrin activation. Specifically, EGF receptor (EGFR)–induced Src activity leads to phosphorylation of a region within the CAS substrate domain, which is essential for Rap1 and αvβ5 activation. This pathway induces αvβ5-mediated invasion and metastasis in vivo yet does not influence primary tumor growth or activation of other integrins on these cells. These findings show cross-talk between a tyrosine kinase receptor and an integrin involved in carcinoma cell invasion and metastasis and may explain in part how inhibitors of EGFR affect malignant disease. [Cancer Res 2009;69(4):1383–91]
Data from Inactivation of the Carney Complex Gene 1 (Protein Kinase A Regulatory Subunit 1A) Inhibits SMAD3 Expression and TGFβ-Stimulated Apoptosis in Adrenocortical Cells
Authors: Ragazzon Bruno , Cazabat Laure , Rizk-Rabin Marthe , Assie Guillaume , Groussin Lionel , Fierrard Hélène , Perlemoine Karine , Martinez Antoine , Bertherat Jérôme
Published: March 2024

Abstract
The cyclic AMP signaling pathway can be altered at multiple levels in endocrine tumors. Its central component is the protein kinase A (PKA). Carney complex (CNC) is a hereditary multiple neoplasia syndrome resulting from inactivating mutations of the gene encoding the PKA type I α regulatory subunit (PRKAR1A). Primary pigmented nodular adrenocortical disease is the most frequent endocrine tumor of CNC. Transforming growth factor β (TGFβ) regulates adrenal cortex physiology and signals through SMAD2/3. We used an interference approach to test the effects of PRKAR1A inactivation on PKA and TGFβ pathways and on apoptosis in adrenocortical cells. PRKAR1A silencing stimulates PKA activity and increases transcriptional activity of a PKA reporter construct and expression of the endogenous PKA target, NR4A2, under basal conditions or after forskolin stimulation. PRKAR1A inactivation also decreased SMAD3 mRNA and protein levels via PKA, altering the cellular response to TGFβ. SMAD3 expression was also inhibited by adrenocorticorticotropic hormone in the mouse adrenal gland and by forskolin in H295R cells. TGFβ stimulates apoptosis in H295R cells, and this effect was counteracted by PRKAR1A inactivation. PRKAR1A silencing decreased the percentage of apoptotic cells and the cleavage of apoptosis mediators [caspase-3, poly(ADP-ribose) polymerase, and lamin A/C]. Inactivating mutations of PRKAR1A observed in adrenocortical tumors alter SMAD3, leading to resistance to TGFβ-induced apoptosis. This cross-talk between the PKA and the TGFβ signaling pathways reveals a new mechanism of endocrine tumorigenesis. [Cancer Res 2009;69(18):7278–84]
Data from MiR-15a and MiR-16 Control Bmi-1 Expression in Ovarian Cancer
Authors: Bhattacharya Resham , Nicoloso Milena , Arvizo Rochelle , Wang Enfeng , Cortez Angelica , Rossi Simona , Calin George A. , Mukherjee Priyabrata
Published: March 2024

Abstract
Oncogenic activation of Bmi-1 is found in a wide variety of epithelial malignancies including ovarian cancer, yet a specific mechanism for overexpression of Bmi-1 has not been determined. Thus, realizing the immense pathologic significance of Bmi-1 in cancer, we wanted to investigate if microRNA (miRNA) aberrations played a role in the regulation of Bmi-1 in ovarian cancer. In this report, we identify two miRNAs, miR-15a and miR-16, that are underexpressed in ovarian cell lines and in primary ovarian tissues. We show that these miRNAs directly target the Bmi-1 3′ untranslated region and significantly correlate with Bmi-1 protein levels in ovarian cancer patients and cell lines. Furthermore, Bmi-1 protein levels are downregulated in response to miR-15a or miR-16 expression and lead to significant reduction in ovarian cancer cell proliferation and clonal growth. These findings suggest the development of therapeutic strategies by restoring miR-15a and miR-16 expression in ovarian cancer and in other cancers that involve upregulation of Bmi-1. [Cancer Res 2009;69(23):9090–5]
Data from Epigenetic Repression of microRNA-129-2 Leads to Overexpression of SOX4 Oncogene in Endometrial Cancer
Authors: Huang Yi-Wen , Liu Joseph C. , Deatherage Daniel E. , Luo Jingqin , Mutch David G. , Goodfellow Paul J. , Miller David S. , Huang Tim H-M.
Published: March 2024

Abstract
Genetic amplification, mutation, and translocation are known to play a causal role in the upregulation of an oncogene in cancer cells. Here, we report an emerging role of microRNA, the epigenetic deregulation of which may also lead to this oncogenic activation. SOX4, an oncogene belonging to the SRY-related high mobility group box family, was found to be overexpressed (P < 0.005) in endometrial tumors (n = 74) compared with uninvolved controls (n = 20). This gene is computationally predicted to be the target of a microRNA, miR-129-2. When compared with the matched endometria, the expression of miR-129-2 was lost in 27 of 31 primary endometrial tumors that also showed a concomitant gain of SOX4 expression (P < 0.001). This inverse relationship is associated with hypermethylation of the miR-129-2 CpG island, which was observed in endometrial cancer cell lines (n = 6) and 68% of 117 endometrioid endometrial tumors analyzed. Reactivation of miR-129-2 in cancer cells by pharmacologic induction of histone acetylation and DNA demethylation resulted in decreased SOX4 expression. In addition, restoration of miR-129-2 by cell transfection led to decreased SOX4 expression and reduced proliferation of cancer cells. Further analysis found a significant correlation of hypermethylated miR-129-2 with microsatellite instability and MLH1 methylation status (P < 0.001) and poor overall survival (P < 0.039) in patients. Therefore, these results imply that the aberrant expression of SOX4 is, in part, caused by epigenetic repression of miR-129-2 in endometrial cancer. Unlike the notion that promoter hypomethylation may upregulate an oncogene, we present a new paradigm in which hypermethylation-mediated silencing of a microRNA derepresses its oncogenic target in cancer cells. [Cancer Res 2009;69(23):9038–46]
Data from Suppression of Integrin α3β1 in Breast Cancer Cells Reduces Cyclooxygenase-2 Gene Expression and Inhibits Tumorigenesis, Invasion, and Cross-Talk to Endothelial Cells
Authors: Mitchell Kara , Svenson Kimberly B. , Longmate Whitney M. , Gkirtzimanaki Katerina , Sadej Rafal , Wang Xianhui , Zhao Jihe , Eliopoulos Aristides G. , Berditchevski Fedor , DiPersio C. Michael
Published: March 2024

Abstract
Integrin receptors for cell adhesion to extracellular matrix have important roles in promoting tumor growth and progression. Integrin α3β1 is highly expressed in breast cancer cells in which it is thought to promote invasion and metastasis; however, its roles in regulating malignant tumor cell behavior remain unclear. In the current study, we used short-hairpin RNA (shRNA) to show that suppression of α3β1 in a human breast cancer cell line, MDA-MB-231, leads to decreased tumorigenicity, reduced invasiveness, and decreased production of factors that stimulate endothelial cell migration. Real-time PCR revealed that suppression of α3β1 caused a dramatic reduction in expression of the cyclooxygenase-2 (COX-2) gene, which is frequently overexpressed in breast cancers and has been exploited as a therapeutic target. Decreased COX-2 was accompanied by reduced prostaglandin E2 (PGE2), a major prostanoid produced downstream of COX-2 and an important effector of COX-2 signaling. shRNA-mediated suppression of COX-2 showed that it has a role in tumor cell invasion and cross-talk to endothelial cells. Furthermore, treatment with PGE2 restored these functions in α3β1-deficient MDA-MB-231 cells. These findings identify a role for α3β1 in regulating two properties of tumor cells that facilitate cancer progression: invasiveness and ability to stimulate endothelial cells. They also reveal a novel role for COX-2 as a downstream effector of α3β1 in tumor cells, thereby identifying α3β1 as a potential therapeutic target to inhibit breast cancer. Cancer Res; 70(15); 6359–67. ©2010 AACR.
Data from Similar Nucleotide Excision Repair Capacity in Melanocytes and Melanoma Cells
Authors: Gaddameedhi Shobhan , Kemp Michael G. , Reardon Joyce T. , Shields Janiel M. , Smith-Roe Stephanie L. , Kaufmann William K. , Sancar Aziz
Published: March 2024

Abstract
Sunlight UV exposure produces DNA photoproducts in skin that are repaired solely by nucleotide excision repair in humans. A significant fraction of melanomas are thought to result from UV-induced DNA damage that escapes repair; however, little evidence is available about the functional capacity of normal human melanocytes, malignant melanoma cells, and metastatic melanoma cells to repair UV-induced photoproducts in DNA. In this study, we measured nucleotide excision repair in both normal melanocytes and a panel of melanoma cell lines. Our results show that in 11 of 12 melanoma cell lines tested, UV photoproduct repair occurred as efficiently as in primary melanocytes. Importantly, repair capacity was not affected by mutation in the N-RAS or B-RAF oncogenes, nor was a difference observed between a highly metastatic melanoma cell line (A375SM) or its parental line (A375P). Lastly, we found that although p53 status contributed to photoproduct removal efficiency, its role did not seem to be mediated by enhanced expression or activity of DNA binding protein DDB2. We concluded that melanoma cells retain capacity for nucleotide excision repair, the loss of which probably does not commonly contribute to melanoma progression. Cancer Res; 70(12); 4922–30. ©2010 AACR.
Data from β1-Integrin Circumvents the Antiproliferative Effects of Trastuzumab in Human Epidermal Growth Factor Receptor-2–Positive Breast Cancer
Authors: Lesniak David , Xu Yaoxian , Deschenes Jean , Lai Raymond , Thoms John , Murray David , Gosh Sunita , Mackey John R. , Sabri Siham , Abdulkarim Bassam
Published: March 2024

Abstract
Resistance to trastuzumab, the monoclonal antibody targeting human epidermal growth factor receptor 2 (HER-2), is a major concern for HER-2–positive metastatic breast cancer (MBC) patients. To date, HER-2 status is the only available biomarker for selecting patients for trastuzumab-based therapy. β1-Integrin, an adhesion molecule involved in cell survival and drug resistance, shares common downstream signaling elements with HER-2, such as the phosphatidylinositol 3-kinase/Akt and extracellular signal-regulated kinase-1/2 (ERK1/2) pathways. The significance of β1-integrin expression in HER-2–positive breast cancer and its involvement in a patient's response to trastuzumab-based therapy are unknown. We show here that overexpression of β1-integrin is an independent negative prognostic factor for tumor progression of HER-2–positive MBC patients treated with trastuzumab-based chemotherapy. Enforced overexpression of β1-integrin, its small interfering RNA–induced knockdown or treatment with a β1-integrin–blocking antibody in HER-2–positive breast cancer cells, identified a strong inverse relationship between expression level of β1-integrin and in vitro sensitivity to trastuzumab. Notably, β1-integrin overexpression increased the phosphorylation of Akt-Ser473 and ERK1/2, thereby promoting survival and mitogenic signals to bypass the antiproliferative effects of trastuzumab. Our findings show that β1-integrin provides a novel independent prognostic biomarker of trastuzumab response in HER-2–positive MBC patients and suggest a new target to augment the antiproliferative effects of trastuzumab. [Cancer Res 2009;69(22):8620–8]
Data from Molecular Causes for BUBR1 Dysfunction in the Human Cancer Predisposition Syndrome Mosaic Variegated Aneuploidy
Authors: Suijkerbuijk Saskia J.E. , van Osch Maria H.J. , Bos Frank L. , Hanks Sandra , Rahman Nazneen , Kops Geert J.P.L.
Published: March 2024

Abstract
Genetic mutations in the mitotic regulatory kinase BUBR1 are associated with the cancer-susceptible disorder mosaic variegated aneuploidy (MVA). In patients with biallelic mutations, a missense mutation pairs with a truncating mutation. Here, we show that cell lines derived from MVA patients with biallelic mutations have an impaired mitotic checkpoint, chromosome alignment defects, and low overall BUBR1 abundance. Ectopic expression of BUBR1 restored mitotic checkpoint activity, proving that BUBR1 dysfunction causes chromosome segregation errors in the patients. Combined analysis of patient cells and functional protein replacement shows that all MVA mutations fall in two distinct classes: those that impose specific defects in checkpoint activity or microtubule attachment and those that lower BUBR1 protein abundance. Low protein abundance is the direct result of the absence of transcripts from truncating mutants combined with high protein turnover of missense mutants. In this group of missense mutants, the amino acid change consistently occurs in or near the BUBR1 kinase domain. Our findings provide a molecular explanation for chromosomal instability in patients with biallelic genetic mutations in BUBR1. Cancer Res; 70(12); 4891–900. ©2010 AACR.
Data from Deficiency in p53 but not Retinoblastoma Induces the Transformation of Mesenchymal Stem Cells In vitro and Initiates Leiomyosarcoma In vivo
Authors: Rubio Ruth , García-Castro Javier , Gutiérrez-Aranda Iván , Paramio Jesús , Santos Mirentxu , Catalina Purificación , Leone Paola E. , Menendez Pablo , Rodríguez René
Published: March 2024

Abstract
Sarcomas have been modeled in mice by the expression of specific fusion genes in mesenchymal stem cells (MSC), supporting the concept that MSCs might be the target initiating cell in sarcoma. In this study, we evaluated the potential oncogenic effects of p53 and/or retinoblastoma (Rb) deficiency in MSC transformation and sarcomagenesis. We derived wild-type, p53−/−, Rb−/−, and p53−/−Rb−/− MSC cultures and fully characterized their in vitro growth properties and in vivo tumorigenesis capabilities. In contrast with wild-type MSCs, Rb−/−, p53−/−, and p53−/−Rb−/− MSCs underwent in vitro transformation and showed severe alterations in culture homeostasis. More importantly, p53−/− and p53−/−Rb−/− MSCs, but not Rb−/− MSCs, were capable of tumor development in vivo after injection into immunodeficient mice. p53−/− or p53−/−Rb−/− MSCs originated leiomyosarcoma-like tumors, linking this type of smooth muscle sarcoma to p53 deficiency in fat tissue–derived MSCs. Sca1+ and Sca1 low/− cell populations isolated from ex vivo–established, transformed MSC lines from p53−/−Rb−/− tumors showed identical sarcomagenesis potential, with 100% tumor penetrance and identical latency, tumor weight, and histologic profile. Our findings define the differential roles of p53 and Rb in MSC transformation and offer proof-of-principle that MSCs could provide useful tools to dissect the sarcoma pathogenesis. Cancer Res; 70(10); 4185–94. ©2010 AACR.
Data from Disruption of Transforming Growth Factor-β Signaling by Five Frequently Methylated Genes Leads to Head and Neck Squamous Cell Carcinoma Pathogenesis
Authors: Bennett Kristi L. , Romigh Todd , Eng Charis
Published: March 2024

Abstract
Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with low survival rates in advanced stages. To facilitate timely diagnosis and improve outcome, early detection markers (e.g., DNA methylation) are crucial for timely cancer diagnosis. In a recent publication, an epigenome-wide screen revealed a set of genes that are commonly methylated and downregulated in head and neck cancers (SEPT9, SLC5A8, FUSSEL18, EBF3, and IRX1). Interestingly, these candidates are potentially involved in the transforming growth factor-β (TGF-β) signaling pathway, which is often disrupted in HNSCC. Therefore, we sought to determine coordinated epigenetic silencing of these candidate genes in HNSCC as potential key disruptors of TGF-β signaling, which could ultimately result in HNSCC progression. Through immunoprecipitation studies, all five of the investigated candidate genes were found to interact with components of the TGF-β pathway. Overexpression of SLC5A8, EBF3, and IRX1 resulted in decreased mitotic activity and increased apoptosis. In addition, EBF3 was found to increase p21 promoter activity, and SMAD2 significantly increased IRX1 promoter activity. These findings are significant because they reveal a set of genes that interact with components of the TGF-β pathway, and their silencing via methylation in HNSCC results in coordinated decrease in apoptosis, increased proliferation, and decreased differentiation. [Cancer Res 2009;69(24):9301–5]
Data from Persistent Cyclooxygenase-2 Inhibition Downregulates NF-κB, Resulting in Chronic Intestinal Inflammation in the Min/+ Mouse Model of Colon Tumorigenesis
Authors: Carothers Adelaide M. , Davids Jennifer S. , Damas Beatrice C. , Bertagnolli Monica M.
Published: March 2024

Abstract
Cyclooxygenase-2 (COX-2) inhibition prevents adenoma formation in humans and mouse models of colon cancer. The selective COX-2 inhibitor celecoxib reduces COX-2 and prostaglandin E2 (PGE2) expression and adenomas in the intestine of Min/+ mice after treatment for several weeks, but prolonged treatment increases PGE2 production, resulting in drug-resistant tumor formation and transforming growth factor β (TGFβ)–dependent intestinal fibrosis. In this study, we examined pathways that regulate COX-2 expression and suppress chronic intestinal inflammation. We show that NF-κB signaling was inhibited in the ileum of Min/+ mice receiving long-term treatment with celecoxib. This effect was associated with inhibition of TGFβ-associated kinase-1 and IκB kinase α/β activities and reduced expression of the Toll-like receptor (TLR) 2 and TLR4 that enhance colonic barrier function. Additionally, we observed reduced activities of protein kinases c-Jun NH2-terminal kinase 1 and protein kinase A and transcription factor cyclic AMP–responsive element binding protein, regulators of COX-2 expression, which cross-talk with NF-κB. In ileum subjected to long-term celecoxib treatment, we noted relatively higher expression of COX-2, vascular endothelial growth factor, and interleukin-1β in Paneth cells, whereas NF-κB and COX-2 were more strongly expressed by an expanded population of stromal myofibroblasts. Our findings argue that celecoxib resistance is an acquired adaptation to changes in the crypt microenvironment that is associated with chronic intestinal inflammation and impaired acute wound-healing responsiveness. Cancer Res; 70(11); 4433–42. ©2010 AACR.
Data from RETRACTED: Differential Effects of VEGFR-1 and VEGFR-2 Inhibition on Tumor Metastases Based on Host Organ Environment
Authors: Lee Yoon-Jin , Karl Daniel L. , Maduekwe Ugwuji N. , Rothrock Courtney , Ryeom Sandra , D'Amore Patricia A. , Yoon Sam S.
Published: March 2024

Abstract
Tumors induce new blood vessel growth primarily from host organ microvascular endothelial cells (EC), and microvasculature differs significantly between the lung and liver. Vascular endothelial growth factor (VEGF or VEGF-A) promotion of tumor angiogenesis is thought to be mediated primarily by VEGF receptor-2 (VEGFR-2). In this study, VEGFR-2 antibody (DC101) inhibited growth of RenCa renal cell carcinoma lung metastases by 26%, whereas VEGFR-1 antibody (MF-1) had no effect. However, VEGFR-2 neutralization had no effect on RenCa liver metastases, whereas VEGFR-1 neutralization decreased RenCa liver metastases by 31%. For CT26 colon carcinoma liver metastases, inhibition of both VEGFR-1 and VEGFR-2 was required to induce growth delay. VEGFR-1 or VEGFR-2 inhibition decreased tumor burden not by preventing the establishment of micrometastases but rather by preventing vascularization and growth of micrometastases by 55% and 43%, respectively. VEGF induced greater phosphorylation of VEGFR-2 in lung ECs and of VEGFR-1 in liver ECs. EC proliferation, migration, and capillary tube formation in vitro were suppressed more by VEGFR-2 inhibition for lung EC and more by VEGFR-1 inhibition for liver EC. Collectively, our results indicate that liver metastases are more reliant on VEGFR-1 than lung metastases to mediate angiogenesis due to differential activity of VEGFRs on liver EC versus lung EC. Thus, therapies inhibiting specific VEGFRs should consider the targeted sites of metastatic disease. Cancer Res; 70(21); 8357–67. ©2010 AACR.
Data from Differential Effects of VEGFR-1 and VEGFR-2 Inhibition on Tumor Metastases Based on Host Organ Environment
Authors: Lee Yoon-Jin , Karl Daniel L. , Maduekwe Ugwuji N. , Rothrock Courtney , Ryeom Sandra , D'Amore Patricia A. , Yoon Sam S.
Published: March 2024

Abstract
Tumors induce new blood vessel growth primarily from host organ microvascular endothelial cells (EC), and microvasculature differs significantly between the lung and liver. Vascular endothelial growth factor (VEGF or VEGF-A) promotion of tumor angiogenesis is thought to be mediated primarily by VEGF receptor-2 (VEGFR-2). In this study, VEGFR-2 antibody (DC101) inhibited growth of RenCa renal cell carcinoma lung metastases by 26%, whereas VEGFR-1 antibody (MF-1) had no effect. However, VEGFR-2 neutralization had no effect on RenCa liver metastases, whereas VEGFR-1 neutralization decreased RenCa liver metastases by 31%. For CT26 colon carcinoma liver metastases, inhibition of both VEGFR-1 and VEGFR-2 was required to induce growth delay. VEGFR-1 or VEGFR-2 inhibition decreased tumor burden not by preventing the establishment of micrometastases but rather by preventing vascularization and growth of micrometastases by 55% and 43%, respectively. VEGF induced greater phosphorylation of VEGFR-2 in lung ECs and of VEGFR-1 in liver ECs. EC proliferation, migration, and capillary tube formation in vitro were suppressed more by VEGFR-2 inhibition for lung EC and more by VEGFR-1 inhibition for liver EC. Collectively, our results indicate that liver metastases are more reliant on VEGFR-1 than lung metastases to mediate angiogenesis due to differential activity of VEGFRs on liver EC versus lung EC. Thus, therapies inhibiting specific VEGFRs should consider the targeted sites of metastatic disease. Cancer Res; 70(21); 8357–67. ©2010 AACR.
Data from Common Botanical Compounds Inhibit the Hedgehog Signaling Pathway in Prostate Cancer
Authors: Ślusarz Anna , Shenouda Nader S. , Sakla Mary S. , Drenkhahn Sara K. , Narula Acharan S. , MacDonald Ruth S. , Besch-Williford Cynthia L. , Lubahn Dennis B.
Published: March 2024

Abstract
Many botanical compounds have been proposed to prevent cancer. We investigated the cancer treatment and prevention abilities of apigenin, baicalein, curcumin, epigallocatechin 3-gallate (EGCG), genistein, quercetin, and resveratrol both in vivo in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice as well as in vitro in prostate cancer cell lines. In our experiments, these seven compounds act similarly to the Hedgehog antagonist cyclopamine, a teratogenic plant alkaloid, which had been previously shown to “cure” prostate cancer in a mouse xenograft model. With IC50 values ranging from <1 to 25 μmol/L, these compounds can inhibit Gli1 mRNA concentration by up to 95% and downregulate Gli reporter activity by 80%. We show that four compounds, genistein, curcumin, EGCG, and resveratrol, inhibit Hedgehog signaling as monitored by real-time reverse transcription-PCR analysis of Gli1 mRNA concentration or by Gli reporter activity. Three compounds, apigenin, baicalein, and quercetin, decreased Gli1 mRNA concentration but not Gli reporter activity. Our results show that these compounds are also able to reduce or delay prostate cancer in vivo in TRAMP mice. All seven compounds, when fed in combination as pure compounds or as crude plant extracts, inhibit well-differentiated carcinoma of the prostate by 58% and 81%, respectively. In vitro, we show that all seven compounds also inhibit growth in human and mouse prostate cancer cell lines. Mechanistically, we propose the Hedgehog signaling pathway to be a direct or indirect target of these compounds. These botanicals at pharmacologic concentrations are potentially safer and less expensive alternatives to cyclopamine and its pharmaceutical analogues for cancer therapy. Cancer Res; 70(8); 3382–90. ©2010 AACR.