bluuebunny/crossref_metadata_2025 huggingface dataset:
Attention Mechanism with Spatial‐Temporal Joint Deep Learning Model for the Forecasting of Short‐Term Passenger Flow Distribution at the Railway Station
Authors: Dai Zhicheng , Li Dewei , Feng Shiqing
Published: March 2024

Accurate understanding of passenger flow distribution is crucial for effective station crowd management. However, due to the complexity and randomness of passenger flow and the unclear spatial‐temporal correlation between functional areas within the station, predicting the spatiotemporal distribution dynamics of inflow and future short‐term distribution trends is challenging. Emerging deep learning models offer valuable insights for accurately predicting passenger flow distribution. Thus, we propose a deep learning architecture, named “ST‐Bi‐LSTM,” which combines a bidirectional long short‐term memory network with a spatial‐temporal attention mechanism. Initially, we outline the methodologies of Bi‐LSTM, the DeepWalk‐based spatial attention mechanism, and the temporal attention mechanism. The spatial attention mechanism is employed to extract station spatial network topology information and enhance the representation of passenger flow characteristics in highly correlated areas during the forecasting process. Simultaneously, the temporal attention Bi‐LSTM is utilized for capturing temporal correlations. The architecture comprises four branches dedicated to station real‐time video monitoring data, spatial network topology, function area attributes, and train timetables. Subsequently, leveraging in‐station CCTV data, passenger travel behavior data, and train timetables, we apply the architecture to the Tianjin West High‐Speed Railway Station. We conduct a comparative analysis of the prediction performance and time complexity of the proposed architecture against existing baseline models, demonstrating superior performance and robustness exhibited by the ST‐Bi‐LSTM model (achieving a reduction in RMSE of over 10%). This study facilitates the transition of station management from passive response to active prediction of station passenger flow dynamics.
Data from Protein Kinase D3 (PKD3) Contributes to Prostate Cancer Cell Growth and Survival Through a PKCε/PKD3 Pathway Downstream of Akt and ERK 1/2
Authors: Chen Jun , Deng Fan , Singh Shivendra V. , Wang Qiming J.
Published: March 2024

Abstract
Protein kinase D (PKD) is a family of novel diacylglycerol/phorbol ester targets that regulate many important cellular functions including cell growth and survival. We now provide experimental evidence to indicate that PKD3 contributes to prostate cancer cell growth and survival. Expression of PKD3 as well as PKD1 was significantly higher in human prostate tumors compared with normal tissues as revealed by immunohistochemistry. Moreover, PKD3 exhibited a marked increase in nuclear localization in tumor tissues, which correlated with tumor grade. Isoforms of PKD were differentially expressed and localized between normal and human prostate cancer cells. Increased protein expression and nuclear accumulation of PKD3 were observed in the more aggressive androgen-independent PC3 and DU145 cells compared with the less aggressive androgen-dependent LNCaP cells. Overexpression of wild-type PKD3 in LNCaP cells blocked phorbol 12-myristate 13-acetate (PMA)-induced apoptosis in association with inhibition of PMA-induced down-regulation of Akt activity, and prolonged extracellular signal-regulated kinase (ERK)1/2 activation. Overexpression of wild-type PKD3 also promoted S phase entry, whereas depletion of endogenous PKD3 resulted in G0-G1 phase cell cycle arrest and inhibition of PC3 cell proliferation. In PC3 and DU145 cells, PKCε regulated PKD3 kinase activity and nuclear localization. Moreover, ectopical expression of PKD3 increased, whereas depletion of endogenous PKD3 reduced basal Akt and ERK1/2 activities. Further analysis showed that up-regulation of Akt activity induced by PKD3 required phosphatidylinositol-3-OH kinase and p38. In summary, our data indicate that PKD3 contributes to growth and survival of prostate cancer cells and may represent a novel therapeutic target for prostate cancer. [Cancer Res 2008;68(10):3844–53]
Data from Rational Drug Redesign to Overcome Drug Resistance in Cancer Therapy: Imatinib Moving Target
Authors: Fernández Ariel , Sanguino Angela , Peng Zhenghong , Crespo Alejandro , Ozturk Eylem , Zhang Xi , Wang Shimei , Bornmann William , Lopez-Berestein Gabriel
Published: March 2024

Abstract
Protein kinases are central targets for drug-based cancer treatment. To avoid functional impairment, the cell develops mechanisms of drug resistance, primarily based on adaptive mutations. Redesigning a drug to target a drug-resistant mutant kinase constitutes a therapeutic challenge. We approach the problem by redesigning the anticancer drug imatinib guided by local changes in interfacial de-wetting propensities of the C-Kit kinase target introduced by an imatinib-resistant mutation. The ligand is redesigned by sculpting the shifting hydration patterns of the target. The association with the modified ligand overcomes the mutation-driven destabilization of the induced fit. Consequently, the redesigned drug inhibits both mutant and wild-type kinase. The modeling effort is validated through molecular dynamics, test tube kinetic assays of downstream phosphorylation activity, high-throughput bacteriophage-display kinase screening, cellular proliferation assays, and cellular immunoblots. The inhibitor redesign reported delineates a molecular engineering paradigm to impair routes for drug resistance. [Cancer Res 2007;67(9):4028–33]
Data from c-Fos as a Proapoptotic Agent in TRAIL-Induced Apoptosis in Prostate Cancer Cells
Authors: Zhang Xiaoping , Zhang Liang , Yang Hongmei , Huang Xu , Otu Hasan , Libermann Towia A. , DeWolf William C. , Khosravi-Far Roya , Olumi Aria F.
Published: March 2024

Abstract
Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)/Apo-2L promotes apoptosis in cancer cells while sparing normal cells. Although many cancers are sensitive to TRAIL-induced apoptosis, some evade the proapoptotic effects of TRAIL. Therefore, differentiating molecular mechanisms that distinguish between TRAIL-sensitive and TRAIL-resistant tumors are essential for effective cancer therapies. Here, we show that c-Fos functions as a proapoptotic agent by repressing the antiapoptotic molecule c-FLIP(L). c-Fos binds the c-FLIP(L) promoter, represses its transcriptional activity, and reduces c-FLIP(L) mRNA and protein levels. Therefore, c-Fos is a key regulator of c-FLIP(L), and activation of c-Fos determines whether a cancer cell will undergo cell death after TRAIL treatment. Strategies to activate c-Fos or inhibit c-FLIP(L) may potentiate TRAIL-based proapoptotic therapies. [Cancer Res 2007;67(19):9425–34]
Data from Characterization of an Akt Kinase Inhibitor with Potent Pharmacodynamic and Antitumor Activity
Authors: Rhodes Nelson , Heerding Dirk A. , Duckett Derek R. , Eberwein Derek J. , Knick Victoria B. , Lansing Timothy J. , McConnell Randy T. , Gilmer Tona M. , Zhang Shu-Yun , Robell Kimberly , Kahana Jason A. , Geske Robert S. , Kleymenova Elena V. , Choudhry Anthony E. , Lai Zhihong , Leber Jack D. , Minthorn Elisabeth A. , Strum Susan L. , Wood Edgar R. , Huang Pearl S. , Copeland Robert A. , Kumar Rakesh
Published: March 2024

Abstract
Akt kinases 1, 2, and 3 are important regulators of cell survival and have been shown to be constitutively active in a variety of human tumors. GSK690693 is a novel ATP-competitive, low-nanomolar pan-Akt kinase inhibitor. It is selective for the Akt isoforms versus the majority of kinases in other families; however, it does inhibit additional members of the AGC kinase family. It causes dose-dependent reductions in the phosphorylation state of multiple proteins downstream of Akt, including GSK3β, PRAS40, and Forkhead. GSK690693 inhibited proliferation and induced apoptosis in a subset of tumor cells with potency consistent with intracellular inhibition of Akt kinase activity. In immune-compromised mice implanted with human BT474 breast carcinoma xenografts, a single i.p. administration of GSK690693 inhibited GSK3β phosphorylation in a dose- and time-dependent manner. After a single dose of GSK690693, >3 μmol/L drug concentration in BT474 tumor xenografts correlated with a sustained decrease in GSK3β phosphorylation. Consistent with the role of Akt in insulin signaling, treatment with GSK690693 resulted in acute and transient increases in blood glucose level. Daily administration of GSK690693 produced significant antitumor activity in mice bearing established human SKOV-3 ovarian, LNCaP prostate, and BT474 and HCC-1954 breast carcinoma xenografts. Immunohistochemical analysis of tumor xenografts after repeat dosing with GSK690693 showed reductions in phosphorylated Akt substrates in vivo. These results support further evaluation of GSK690693 as an anticancer agent. [Cancer Res 2008;68(7):2366–74]
Data from Reduction in IκB Kinase α Expression Promotes the Development of Skin Papillomas and Carcinomas
Authors: Park Eunmi , Zhu Feng , Liu Bigang , Xia Xiaojun , Shen Jianjun , Bustos Tracie , Fischer Susan M. , Hu Yinling
Published: March 2024

Abstract
We reported recently a marked reduction in IκB kinase α (IKKα) expression in a large proportion of human poorly differentiated squamous cell carcinomas (SCC) and the occurrence of Ikkα mutations in human SCCs. In addition, overexpression of IKKα in the epidermis inhibited the development of skin carcinomas and metastases in mice. However, whether a reduction in IKKα expression promotes skin tumor development is currently unknown. Here, we assessed the susceptibility of Ikkα hemizygotes to chemical carcinogen-induced skin carcinogenesis. Ikkα+/− mice developed 2 times more papillomas and 11 times more carcinomas than did Ikkα+/+ mice. The tumors were larger in Ikkα+/− than in Ikkα+/+ mice, but tumor latency was shorter in Ikkα+/− than in Ikkα+/+ mice. Some of the Ikkα+/− papillomas and most Ikkα+/− carcinomas lost the remaining Ikkα wild-type allele. Somatic Ikkα mutations were detected in carcinomas and papillomas. The chemical carcinogen-induced H-Ras mutations were detected in all the tumors. The phorbol ester tumor promoter induced higher mitogenic and angiogenic activities in Ikkα+/− than in Ikkα+/+ skin. These elevated activities were intrinsic to keratinocytes, suggesting that a reduction in IKKα expression provided a selective growth advantage, which cooperated with H-Ras mutations to promote papilloma formation. Furthermore, excessive extracellular signal-regulated kinase and IKK kinase activities were observed in carcinomas compared with those in papillomas. Thus, the combined mitogenic, angiogenic, and IKK activities might contribute to malignant conversion. Our findings provide evidence that a reduction in IKKα expression promotes the development of papillomas and carcinomas and that the integrity of the Ikkα gene is required for suppressing skin carcinogenesis. [Cancer Res 2007;67(19):9158–68]
Data from ΔDNMT3B Variants Regulate DNA Methylation in a Promoter-Specific Manner
Authors: Wang Jie , Bhutani Manisha , Pathak Ashutosh K. , Lang Wenhua , Ren Hening , Jelinek Jaroslav , He Rong , Shen Lanlan , Issa Jean-Pierre , Mao Li
Published: March 2024

Abstract
DNA methyltransferase 3B (DNMT3B) is critical in de novo DNA methylation during development and tumorigenesis. We recently reported the identification of a DNMT3B subfamily, ΔDNMT3B, which contains at least seven variants, resulting from alternative pre-mRNA splicing. ΔDNMT3Bs are the predominant expression forms of DNMT3B in human lung cancer. A strong correlation was observed between the promoter methylation of RASSF1A gene but not p16 gene (both frequently inactivated by promoter methylation in lung cancer) and expression of ΔDNMT3B4 in primary lung cancer, suggesting a role of ΔDNMT3B in regulating promoter-specific methylation of common tumor suppressor genes in tumorigenesis. In this report, we provide first experimental evidence showing a direct involvement of ΔDNMT3B4 in regulating RASSF1A promoter methylation in human lung cancer cells. Knockdown of ΔDNMT3B4 expression by small interfering RNA resulted in a rapid demethylation of RASSF1A promoter and reexpression of RASSF1A mRNA but had no effect on p16 promoter in the lung cancer cells. Conversely, normal bronchial epithelial cells with stably transfected ΔDNMT3B4 gained an increased DNA methylation in RASSF1A promoter but not p16 promoter. We conclude that promoter DNA methylation can be differentially regulated and ΔDNMT3Bs are involved in regulation of such promoter-specific de novo DNA methylation. [Cancer Res 2007;67(22):10647–52]
Data from Inhibition of MAPK Kinase Signaling Pathways Suppressed Renal Cell Carcinoma Growth and Angiogenesis In vivo
Authors: Huang Dan , Ding Yan , Luo Wang-Mei , Bender Stephanie , Qian Chao-Nan , Kort Eric , Zhang Zhong-Fa , VandenBeldt Kristin , Duesbery Nicholas S. , Resau James H. , Teh Bin Tean
Published: March 2024

Abstract
The mitogen-activated protein kinase (MAPK) signaling pathways play essential roles in cell proliferation and differentiation. Recent studies also show the activation of MAPK signaling pathways in tumorigenesis, metastasis, and angiogenesis of multiple human malignancies, including renal cell carcinoma (RCC). To assess the role of this pathway in regulating the proliferation and survival of RCC cells, we first examined the expression of MAPK kinase (MKK) and MAPK in clear cell RCC and confirmed the overexpression of MKK1 and extracellular signal-regulated kinase 2 (ERK2) in these tumors. We then tested the effects of pharmacologic inhibition of MKK on human RCC cell lines, both in vitro and in vivo, using anthrax lethal toxin (LeTx), which cleaves and inactivates several MKKs. Western blotting showed that the phosphorylation levels of ERK, c-Jun-NH2 kinase, and p38 MAPK decreased after 72 h of LeTx treatment. Exposure to LeTx for 72 h reduced cell proliferation by 20% without significant effects on cell cycle distribution and apoptosis. Anchorage-independent growth of RCC cells was dramatically inhibited by LeTx. In vivo studies showed that tumor growth of RCC xenografts could be suppressed by LeTx. Extensive necrosis and decreased tumor neovascularization were observed after LeTx treatment. LeTx also showed direct inhibition of proliferation of endothelial cells in vitro. Our results suggest that suppression of one or more MAPK signaling pathways may inhibit RCC growth through the disruption of tumor vasculature. [Cancer Res 2008;68(1):81–8]
Data from Histone Deacetylase Inhibitors Induce Cell Death Selectively in Cells That Harbor Activated kRasV12: The Role of Signal Transducers and Activators of Transcription 1 and p21
Authors: Klampfer Lidija , Huang Jie , Shirasawa Senji , Sasazuki Takehiko , Augenlicht Leonard
Published: March 2024

Abstract
Histone deacetylase (HDAC) inhibitors (HDACi) show potent and selective antitumor activity despite the fact that they induce histone hyperacetylation in both normal and tumor cells. In this study, we showed that the inducible expression of kRasV12 in nontransformed intestinal epithelial cells significantly lowered the mitochondrial membrane potential (MMP) and sensitized cells to HDACi-induced apoptosis. Consistent with our finding that colon cancer cell lines with mutant Ras have reduced expression of signal transducers and activators of transcription 1 (STAT1), we showed that inducible expression of mutant Ras markedly decreased both basal and inducible expression of STAT1, a transcription factor with tumor suppressor activity. To investigate whether reduced expression of STAT1 in cells that harbor mutant Ras contributes to their increased sensitivity to HDACi, we silenced the expression of STAT1 in HKe-3 cells with small interfering RNA. Despite the fact that silencing of STAT1 was not sufficient to alter the MMP, STAT1 deficiency, like Ras mutations, sensitized cells to apoptosis induced by HDACi. We showed that the induction of p21 by HDACi was significantly impaired in HKe-3 cells with silenced STAT1 expression and showed that the ability of butyrate to activate p21 transcription was diminished in STAT1-deficient HKe-3 cells. Finally, we used cells with targeted deletion of p21 to confirm that p21 protects cells from butyrate-induced apoptosis, strongly suggesting that in these cells STAT1 deficiency promotes butyrate-induced apoptosis through impaired induction of p21. Our data therefore establish that Ras mutations, and consequent reduction in the expression of STAT1, underlie the increased susceptibility of transformed cells to undergo apoptosis in response to treatment with inhibitors of HDAC activity. [Cancer Res 2007;67(18):8477–85]
Data from Drug Sensitivity Prediction by CpG Island Methylation Profile in the NCI-60 Cancer Cell Line Panel
Authors: Shen Lanlan , Kondo Yutaka , Ahmed Saira , Boumber Yanis , Konishi Kazuo , Guo Yi , Chen Xinli , Vilaythong Jill N. , Issa Jean-Pierre J.
Published: March 2024

Abstract
Aberrant promoter hypermethylation and associated gene silencing are epigenetic hallmarks of tumorigenesis. It has been suggested that aberrant DNA methylation can affect the sensitivity of cancers to antineoplastic agents by altering expression of genes critical to drug response. To study this issue, we used bisulfite PCR to assess DNA methylation of 32 promoter-associated CpG islands in human cancer cell lines from the National Cancer Institute (NCI) drug-screening panel (NCI-60 panel). The frequency of aberrant hypermethylation of these islands ranged from 2% to 81% in NCI-60 cancer cells, and provided a database that can be analyzed for the sensitivity to ≈30,000 drugs tested in this panel. By correlating drug activity with DNA methylation, we identified a list of methylation markers that predict sensitivity to chemotherapeutic drugs. Among them, hypermethylation of the p53 homologue p73 and associated gene silencing was strongly correlated with sensitivity to alkylating agents. We used small interfering RNA to down-regulate p73 expression in multiple cell lines, including the resistant cell lines TK10 (renal cancer) and SKMEL28 (melanoma). Down-regulating p73 substantially increased sensitivity to commonly used alkylating agents, including cisplatin, indicating that epigenetic silencing of p73 directly modulates drug sensitivity. Our results confirm that epigenetic profiles are useful in identifying molecular mediators for cancer drug sensitivity (pharmaco-epigenomics). [Cancer Res 2007;67(23):11335–43]
Data from Genetic Alterations in the Tyrosine Kinase Transcriptome of Human Cancer Cell Lines
Authors: Ruhe Jens E. , Streit Sylvia , Hart Stefan , Wong Chee-Hong , Specht Katja , Knyazev Pjotr , Knyazeva Tatjana , Tay Liang Seah , Loo Hooi Linn , Foo Priscilla , Wong Winnie , Pok Sharon , Lim Shu Jing , Ong Huimin , Luo Ming , Ho Han Kiat , Peng Kaitian , Lee Tze Chuen , Bezler Martin , Mann Christian , Gaertner Silvia , Hoefler Heinz , Iacobelli Stefano , Peter Stephan , Tay Alice , Brenner Sydney , Venkatesh Byrappa , Ullrich Axel
Published: March 2024

Abstract
Protein tyrosine kinases (PTKs) play a critical role in the manifestation of cancer cell properties, and respective signaling mechanisms have been studied extensively on immortalized tumor cells. To characterize and analyze commonly used cancer cell lines with regard to variations in the primary structure of all expressed PTKs, we conducted a cDNA-based sequence analysis of the entire tyrosine kinase transcriptome of 254 established tumor cell lines. The profiles of cell line intrinsic PTK transcript alterations and the evaluation of 155 identified polymorphisms and 234 somatic mutations are made available in a database designated “Tykiva” (tyrosine kinome variant). Tissue distribution analysis and/or the localization within defined protein domains indicate functional relevance of several genetic alterations. The cysteine replacement of the highly conserved Y367 residue in fibroblast growth factor receptor 4 or the Q26X nonsense mutation in the tumor-suppressor kinase CSK are examples, and may contribute to cell line–specific signaling characteristics and tumor progression. Moreover, known variants, such as epidermal growth factor receptor G719S, that were shown to mediate anticancer drug sensitivity could be detected in other than the previously reported tumor types. Our data therefore provide extensive system information for the design and interpretation of cell line–based cancer research, and may stimulate further investigations into broader clinical applications of current cancer therapeutics. [Cancer Res 2007;67(23):11368–76]
Data from Chimeric NKG2D–Modified T Cells Inhibit Systemic T-Cell Lymphoma Growth in a Manner Involving Multiple Cytokines and Cytotoxic Pathways
Authors: Zhang Tong , Barber Amorette , Sentman Charles L.
Published: March 2024

Abstract
In this study, the efficacy and mechanisms of chimeric NKG2D receptor (chNKG2D)–modified T cells in eliminating NKG2D ligand–positive RMA/Rae1 lymphoma cells were evaluated. Intravenous injection of RMA/Rae1 cells led to significant tumor formation in spleens and lymph nodes within 2 weeks. Adoptive transfer of chNKG2D-modified T cells after tumor injection significantly reduced tumor burdens in both spleens and lymph nodes, and prolonged the survival of tumor-bearing mice. Multiple treatments with chNKG2D T cells resulted in long-term tumor-free survival. Moreover, these long-term survivors were resistant to rechallenge with RMA tumor cells (NKG2D ligand–negative), and their spleen and lymph node cells produced IFN-γ in response to RMA but not to other tumors in vitro, indicating immunity against RMA tumor antigens. ChNKG2D T cell–derived IFN-γ and granulocyte-macrophage colony–stimulating factor, but not perforin (Pfp), tumor necrosis factor–related apoptosis-inducing ligand, or Fas ligand (FasL) alone were critical for in vivo efficacy. T cells deficient in both Pfp and FasL did not kill NKG2D ligand–positive RMA cells in vitro. Adoptive transfer of Pfp−/−FasL−/− chNKG2D T cells had reduced in vivo efficacy, indicating that chNKG2D T cells used both mechanisms to attack RMA/Rae1 cells. Taken together, these results indicate that chNKG2D T-cell–mediated therapeutic effects are mediated by both cytokine-dependent and cytotoxic mechanisms in vivo. [Cancer Res 2007;67(22):11029–36]
Data from Angiopoietin-2 Stimulates Breast Cancer Metastasis through the α5β1 Integrin-Mediated Pathway
Authors: Imanishi Yorihisha , Hu Bo , Jarzynka Michael J. , Guo Ping , Elishaev Esther , Bar-Joseph Ifat , Cheng Shi-Yuan
Published: March 2024

Abstract
Acquisition of a metastatic phenotype by breast cancer cells includes alternations of multigenic programs that permit tumor cells to metastasize to distant organs. Here, we report that angiopoietin-2 (Ang2), a known growth factor, is capable of promoting breast cancer cell invasion leading to metastasis. Analysis of 185 primary human breast cancer specimens that include 97 tumors showing lymph node and/or distant metastasis reveals a significant correlation between the expression of Ang2 and E-cadherin, Snail, metastatic potential, tumor grade, and lymph-vascular invasion during breast cancer progression. Using a xenograft model, we show that overexpression of Ang2 in poorly metastatic MCF-7 breast cancer cells suppresses expression of E-cadherin and induces Snail expression and phosphorylation of Akt and glycogen synthase kinase-3β (GSK-3β) promoting metastasis to the lymph nodes and lung. In cell culture, Ang2 promotes cell migration and invasion in Tie2-deficient breast cancer cells through the α5β1 integrin/integrin-linked kinase (ILK)/Akt, GSK-3β/Snail/E-cadherin signaling pathway. Inhibition of ILK and the α5β1 integrin abrogates Ang2 modulation of Akt, GSK-3β, Snail, and E-cadherin and Ang2-stimulated breast cancer cell migration and invasion. Together, these results underscore the significant contribution of Ang2 in cancer progression, not only by stimulating angiogenesis but also by promoting metastasis, and provide a mechanism by which breast cancer cells acquire an enhanced invasive phenotype contributing to metastasis. [Cancer Res 2007;67(9):4254–63]
Data from Lapatinib (Tykerb, GW572016) Reverses Multidrug Resistance in Cancer Cells by Inhibiting the Activity of ATP-Binding Cassette Subfamily B Member 1 and G Member 2
Authors: Dai Chun-ling , Tiwari Amit K. , Wu Chung-Pu , Su Xiao-dong , Wang Si-Rong , Liu Dong-geng , Ashby Charles R. , Huang Yan , Robey Robert W. , Liang Yong-ju , Chen Li-ming , Shi Cheng-Jun , Ambudkar Suresh V. , Chen Zhe-Sheng , Fu Li-wu
Published: March 2024

Abstract
Lapatinib is active at the ATP-binding site of tyrosine kinases that are associated with the human epidermal growth factor receptor (Her-1 or ErbB1) and Her-2. It is conceivable that lapatinib may inhibit the function of ATP-binding cassette (ABC) transporters by binding to their ATP-binding sites. The aim of this study was to investigate the ability of lapatinib to reverse tumor multidrug resistance (MDR) due to overexpression of ABC subfamily B member 1 (ABCB1) and ABC subfamily G member 2 (ABCG2) transporters. Our results showed that lapatinib significantly enhanced the sensitivity to ABCB1 or ABCG2 substrates in cells expressing these transporters, although a small synergetic effect was observed in combining lapatinib and conventional chemotherapeutic agents in parental sensitive MCF-7 or S1 cells. Lapatinib alone, however, did not significantly alter the sensitivity of non-ABCB1 or non-ABCG2 substrates in sensitive and resistant cells. Additionally, lapatinib significantly increased the accumulation of doxorubicin or mitoxantrone in ABCB1- or ABCG2-overexpressing cells and inhibited the transport of methotrexate and E217βG by ABCG2. Furthermore, lapatinib stimulated the ATPase activity of both ABCB1 and ABCG2 and inhibited the photolabeling of ABCB1 or ABCG2 with [125I]iodoarylazidoprazosin in a concentration-dependent manner. However, lapatinib did not affect the expression of these transporters at mRNA or protein levels. Importantly, lapatinib also strongly enhanced the effect of paclitaxel on the inhibition of growth of the ABCB1-overexpressing KBv200 cell xenografts in nude mice. Overall, we conclude that lapatinib reverses ABCB1- and ABCG2-mediated MDR by directly inhibiting their transport function. These findings may be useful for cancer combinational therapy with lapatinib in the clinic. [Cancer Res 2008;68(19):7905–14]
Data from Genome-Wide Analysis of Aromatase Inhibitor-Resistant, Tamoxifen-Resistant, and Long-Term Estrogen-Deprived Cells Reveals a Role for Estrogen Receptor
Authors: Masri Selma , Phung Sheryl , Wang Xin , Wu Xiwei , Yuan Yate-Ching , Wagman Lawrence , Chen Shiuan
Published: March 2024

Abstract
Acquired resistance to either tamoxifen or aromatase inhibitors (AI) develops after prolonged treatment in a majority of hormone-responsive breast cancers. In an attempt to further elucidate mechanisms of acquired resistance to AIs, MCF-7aro cells resistant to letrozole (T+LET R), anastrozole (T+ANA R), and exemestane (T+EXE R), as well as long-term estrogen deprived (LTEDaro) and tamoxifen-resistant (T+TAM R) lines were generated. This is the first complete panel of endocrine therapy–resistant cell lines, which were generated as multiple independent biological replicates for unbiased genome-wide analysis using affymetrix microarrays. Although similarities are apparent, microarray results clearly show gene signatures unique to AI-resistance were inherently different from LTEDaro and T+TAM R gene expression profiles. Based on hierarchical clustering, unique estrogen-responsive gene signatures vary depending on cell line, with some genes up-regulated in all lines versus other genes up-regulated only in the AI-resistant lines. Characterization of these resistant lines showed that LTEDaro, T+LET R, and T+ANA R cells contained a constitutively active estrogen receptor (ER)α that does not require estrogen for activation. This ligand-independent activation of ER was not observed in the parental cells, as well as T+EXE R and T+TAM R cells. Further characterization of these resistant lines was performed using cell cycle analysis, immunofluorescence experiments to visualize ER subcellular localization, as well as cross-resistance studies to determine second-line inhibitor response. Using this well-defined model system, our studies provide important information regarding differences in resistance mechanisms to AIs, TAM, and LTEDaro, which are critical in overcoming resistance when treating hormone-responsive breast cancers. [Cancer Res 2008;68(12):4910–8]
Data from Polo-like Kinase 3 Functions as a Tumor Suppressor and Is a Negative Regulator of Hypoxia-Inducible Factor-1α under Hypoxic Conditions
Authors: Yang Yali , Bai Jingxiang , Shen Rulong , Brown Sharron A.N. , Komissarova Elena , Huang Ying , Jiang Ning , Alberts Gregory F. , Costa Max , Lu Luo , Winkles Jeffrey A. , Dai Wei
Published: March 2024

Abstract
Polo-like kinase 3 (Plk3) is an important mediator of the cellular responses to genotoxic stresses. In this study, we examined the physiologic function of Plk3 by generating Plk3-deficient mice. Plk3−/− mice displayed an increase in weight and developed tumors in various organs at advanced age. Many tumors in Plk3−/− mice were large in size, exhibiting enhanced angiogenesis. Plk3−/− mouse embryonic fibroblasts were hypersensitive to the induction of hypoxia-inducible factor-1α (HIF-1α) under hypoxic conditions or by nickel and cobalt ion treatments. Ectopic expression of the Plk3-kinase domain (Plk3-KD), but not its Polo-box domain or a Plk3-KD mutant, suppressed the nuclear accumulation of HIF-1α induced by nickel or cobalt ions. Moreover, hypoxia-induced HIF-1α expression was tightly associated with a significant down-regulation of Plk3 expression in HeLa cells. Given the importance of HIF-1α in mediating the activation of the “survival machinery” in cancer cells, these studies strongly suggest that enhanced tumorigenesis in Plk3-null mice is at least partially mediated by a deregulated HIF-1 pathway. [Cancer Res 2008;68(11):4077–85]
Data from CAAT/Enhancer Binding Protein Homologous Protein–Dependent Death Receptor 5 Induction Is a Major Component of SHetA2-Induced Apoptosis in Lung Cancer Cells
Authors: Lin Yi-Dan , Chen Shuzhen , Yue Ping , Zou Wei , Benbrook Doris M. , Liu Shengquan , Le Thanh C. , Berlin K. Darrell , Khuri Fadlo R. , Sun Shi-Yong
Published: March 2024

Abstract
The flexible heteroarotinoids (Flex-Het) represent a novel type of atypical retinoids lacking activity in binding to and transactivating retinoid receptors. Preclinical studies have shown that Flex-Hets induce apoptosis of cancer cells while sparing normal cells and exhibit anticancer activity in vivo with improved therapeutic ratios over conventional retinoid receptor agonists. Flex-Hets have been shown to induce apoptosis through activation of the intrinsic apoptotic pathway. The present study has revealed a novel mechanism underlying Flex-Het–induced apoptosis involving induction of death receptor 5 (DR5). The representative Flex-Het SHetA2 effectively inhibited the growth of human lung cancer cells in cell culture and in mice. SHetA2 induced apoptosis, which could be abrogated by silencing caspase-8 expression, indicating that ShetA2 triggers a caspase-8–dependent apoptosis. Accordingly, SHetA2 up-regulated DR5 expression, including cell surface levels of DR5, and augmented tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)–induced apoptosis. Importantly, small interfering RNA (siRNA)–mediated blockade of DR5 induction conferred cell resistance to SHetA2-induced apoptosis, as well as SHetA2/TRAIL-induced apoptosis. These results show that DR5 induction is a key component of apoptosis induced by SHetA2 or by SHetA2 combined with TRAIL. SHetA2 exerted CAAT/enhancer-binding protein homologous protein (CHOP)–dependent transactivation of the DR5 promoter. Consistently, SHetA2 induced CHOP expression, which paralleled DR5 up-regulation, whereas siRNA-mediated blockage of CHOP induction prevented DR5 up-regulation, indicating CHOP-dependent DR5 up-regulation by SHetA2. Collectively, we conclude that CHOP-dependent DR5 up-regulation is a key event mediating SHetA2-induced apoptosis. [Cancer Res 2008;68(13):5335–44]
Data from Inhibition of the Ras-Net (Elk-3) Pathway by a Novel Pyrazole that Affects Microtubules
Authors: Wasylyk Christine , Zheng Hong , Castell Christelle , Debussche Laurent , Multon Marie-Christine , Wasylyk Bohdan
Published: March 2024

Abstract
Net (Elk-3/SAP-2/Erp) is a transcription factor that is phosphorylated and activated by the Ras–extracellular signal-regulated kinase (Erk) signaling pathway and is involved in wound healing, angiogenesis, and tumor growth. In a cell-based screen for small molecule inhibitors of Ras activation of Net transcriptional activity, we identified a novel pyrazole, XRP44X. XRP44X inhibits fibroblast growth factor 2 (FGF-2)–induced Net phosphorylation by the Ras-Erk signaling upstream from Ras. It also binds to the colchicine-binding site of tubulin, depolymerizes microtubules, stimulates cell membrane blebbing, and affects the morphology of the actin skeleton. Interestingly, Combretastin-A4, which produces similar effects on the cytoskeleton, also inhibits FGF-2 Ras-Net signaling. This differs from other classes of agents that target microtubules, which have either little effect (vincristine) or no effect (docetaxel and nocodazole) on the Ras-Net pathway. XRP44X inhibits various cellular properties, including cell growth, cell cycle progression, and aortal sprouting, similar to other molecules that bind to the tubulin colchicine site. XRP44X has the potentially interesting property of connecting two important pathways involved in cell transformation and may thereby represent an interesting class of molecules that could be developed for cancer treatment. [Cancer Res 2008;68(5):1275–83]
Data from Pten Haploinsufficiency Accelerates Formation of High-Grade Astrocytomas
Authors: Kwon Chang-Hyuk , Zhao Dawen , Chen Jian , Alcantara Sheila , Li Yanjiao , Burns Dennis K. , Mason Ralph P. , Lee Eva Y.-H. P. , Wu Hong , Parada Luis F.
Published: March 2024

Abstract
We previously reported that central nervous system (CNS) inactivation of Nf1 and p53 tumor suppressor genes in mice results in the development of low-grade to high-grade progressive astrocytomas. When the tumors achieve high grade, they are frequently accompanied by Akt activation, reminiscent of the frequent association of PTEN mutations in human high-grade glioma. In the present study, we introduced CNS heterozygosity of Pten into the Nf1/p53 astrocytoma model. Resulting mice had accelerated morbidity, shortened survival, and full penetrance of high-grade astrocytomas. Haploinsufficiency of Pten accelerated formation of grade 3 astrocytomas, whereas loss of Pten heterozygosity and Akt activation coincided with progression into grade 4 tumors. These data suggest that successive loss of each Pten allele may contribute to de novo formation of high-grade astrocytoma and progression into glioblastoma, respectively, thus providing insight into the etiology of primary glioblastoma. The presence of ectopically migrating neural stem/progenitor lineage cells in presymptomatic Pten-deficient mutant brains supports the notion that these tumors may arise from stem/progenitor cells. [Cancer Res 2008;68(9):3286–94]
Data from Identification of Hypoxia-Inducible Factor-1α as a Novel Target for miR-17-92 MicroRNA Cluster
Authors: Taguchi Ayumu , Yanagisawa Kiyoshi , Tanaka Masaharu , Cao Ke , Matsuyama Yasushi , Goto Hidemi , Takahashi Takashi
Published: March 2024

Abstract
MicroRNAs (miRNAs) are a distinct class of small noncoding RNAs that posttranscriptionally repress expression of target genes through imperfect base pairing with the 3′ untranslated region. We previously reported amplification and overexpression of the miR-17-92 miRNA cluster at 13q31.3 in lung cancers, as well as growth inhibition by treatment with antisense oligonucleotides against miR-17-5p and miR-20a, constituents of miR-17-92, specifically in miR-17-92–overexpressing lung cancer cell lines. Although these findings clearly suggested important roles of miR-17-92 overexpression in lung cancers, only a few targets for the miR-17-92 cluster have been identified thus far. In this study, we identified hypoxia-inducible factor (HIF)-1α as a novel direct target for miR-17-92 through global expression profiling by mass spectrometric analysis using an isobaric tagging reagent, iTRAQ, combined with bioinformatic target prediction. This is the first report to describe negative regulation of HIF-1α by miRNA, which seemed to occur without disrupting the induction of HIF-1α for cellular adaptation to hypoxia. In addition, overexpression of c-myc led to down-regulation of HIF-1α and induction of miR-17-92, the latter of which was previously reported to be a transcriptional activation activity, suggesting that the induction of miR-17-92 may play a role at least in part in c-myc–mediated repression of HIF-1α. Together with previous reports on the functional negative regulation of c-myc by HIF-1α, our findings suggest the possible existence of an intricate and finely tuned circuit involving c-myc, miR-17-92, and HIF-1α that may play a role in cancer cell proliferation under normoxia in a cellular context–dependent manner. [Cancer Res 2008;68(14):5540–5]
Data from Loss of E-Cadherin Promotes Metastasis via Multiple Downstream Transcriptional Pathways
Authors: Onder Tamer T. , Gupta Piyush B. , Mani Sendurai A. , Yang Jing , Lander Eric S. , Weinberg Robert A.
Published: March 2024

Abstract
Loss of the epithelial adhesion molecule E-cadherin is thought to enable metastasis by disrupting intercellular contacts—an early step in metastatic dissemination. To further investigate the molecular basis of this notion, we use two methods to inhibit E-cadherin function that distinguish between E-cadherin's cell-cell adhesion and intracellular signaling functions. Whereas the disruption of cell-cell contacts alone does not enable metastasis, the loss of E-cadherin protein does, through induction of an epithelial-to-mesenchymal transition, invasiveness, and anoikis resistance. We find the E-cadherin binding partner β-catenin to be necessary, but not sufficient, for induction of these phenotypes. In addition, gene expression analysis shows that E-cadherin loss results in the induction of multiple transcription factors, at least one of which, Twist, is necessary for E-cadherin loss–induced metastasis. These findings indicate that E-cadherin loss in tumors contributes to metastatic dissemination by inducing wide-ranging transcriptional and functional changes. [Cancer Res 2008;68(10):3645–53]
Data from Noninvasive Imaging and Quantification of Epidermal Growth Factor Receptor Kinase Activation In vivo
Authors: Li Wenrong , Li Fang , Huang Qian , Frederick Barbara , Bao Shideng , Li Chuan-Yuan
Published: March 2024

Abstract
Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) critical in tumor growth and a major target for anticancer drug development. However, thus far, there is no effective system to monitor its activities in vivo. Here, we report a novel approach to monitor EGFR activation based on the bifragment luciferase reconstitution system. The EGFR receptor and its interacting partner proteins (EGFR, growth factor receptor binding protein 2, and Src homology 2 domain-containing) were fused to NH2 terminal and COOH terminal fragments of the firefly luciferase. After establishing tumor xenograft from cells transduced with the reporter genes, we show that the activation of EGFR and its downstream factors could be quantified through optical imaging of reconstituted luciferase. Changes in EGFR activation could be visualized after radiotherapy or EGFR inhibitor treatment. Rapid and sustained radiation-induced EGFR activation and inhibitor-mediated signal suppression were observed in the same xenograft tumors over a period of weeks. Our data therefore suggest a new methodology where activities of RTKs can be imaged and quantified optically in mice. This approach should be generally applicable to study biological regulation of RTK, as well as to develop and evaluate novel RTK-targeted therapeutics. [Cancer Res 2008;68(13):4990–7]
Data from Genome-Wide Analysis of the Homeobox C6 Transcriptional Network in Prostate Cancer
Authors: McCabe Colleen D. , Spyropoulos Demetri D. , Martin David , Moreno Carlos S.
Published: March 2024

Abstract
Homeobox transcription factors are developmentally regulated genes that play crucial roles in tissue patterning. Homeobox C6 (HOXC6) is overexpressed in prostate cancers and correlated with cancer progression, but the downstream targets of HOXC6 are largely unknown. We have performed genome-wide localization analysis to identify promoters bound by HOXC6 in prostate cancer cells. This analysis identified 468 reproducibly bound promoters whose associated genes are involved in functions such as cell proliferation and apoptosis. We have complemented these data with expression profiling of prostates from mice with homozygous disruption of the Hoxc6 gene to identify 31 direct regulatory target genes of HOXC6. We show that HOXC6 directly regulates expression of bone morphogenic protein 7, fibroblast growth factor receptor 2, insulin-like growth factor binding protein 3, and platelet-derived growth factor receptor α (PDGFRA) in prostate cells and indirectly influences the Notch and Wnt signaling pathways in vivo. We further show that inhibition of PDGFRA reduces proliferation of prostate cancer cells, and that overexpression of HOXC6 can overcome the effects of PDGFRA inhibition. HOXC6 regulates genes with both oncogenic and tumor suppressor activities as well as several genes such as CD44 that are important for prostate branching morphogenesis and metastasis to the bone microenvironment. [Cancer Res 2008;68(6):1988–96]
Data from The SV40 Large T Antigen-p53 Complexes Bind and Activate the Insulin-like Growth Factor-I Promoter Stimulating Cell Growth
Authors: Bocchetta Maurizio , Eliasz Sandra , De Marco Melissa Arakelian , Rudzinski Jennifer , Zhang Lei , Carbone Michele
Published: March 2024

Abstract
Inactivation of cellular p53 is a crucial step in carcinogenesis. Accordingly, p53 is inactivated in most human cancers by different mechanisms. In cells infected with DNA tumor viruses, p53 is bound to the viral tumor antigens (Tag). The current “dogma” views the Tag-p53 complexes as a way of sequestering and inactivating p53. Using primary human cells and SV40-transformed human cells, we show that in addition to inactivating p53 tumor suppressor activities, the Tag-p53 complex has growth stimulatory activities that are required for malignant cell growth. We found that in human cells, Tag-p53 complexes regulate transcription of the insulin-like growth factor I (IGF-I) gene by binding to the IGF-I promoter together with pRb and p300. Depletion of p53 leads to structural rearrangements of this multiprotein complex, resulting in IGF-I promoter transcriptional repression and growth arrest. Our data provide a novel mechanistic and biological interpretation of the p53-Tag complexes and of DNA tumor virus transformation in general. In the model we propose, p53 is not a passive inactive partner of Tag. Instead the p53-Tag complex promotes malignant cell growth through its ability to activate the IGF-I signaling pathway. [Cancer Res 2008;68(4):1022–9]
Data from Transforming Growth Factor β Induces Apoptosis through Repressing the Phosphoinositide 3-Kinase/AKT/Survivin Pathway in Colon Cancer Cells
Authors: Wang Jing , Yang Limin , Yang Junhua , Kuropatwinski Karen , Wang Wang , Liu Xiao-Qiong , Hauser Jennie , Brattain Michael G.
Published: March 2024

Abstract
FET cells, derived from an early-stage colon carcinoma, are nontumorigenic in athymic mice. Stable transfection of a dominant-negative transforming growth factor β (TGFβ) type II receptor (DNRII) into FET cells that express autocrine TGFβ shows loss of TGFβ signaling and increased tumorigenicity in vivo indicating tumor suppressor activity of TGFβ signaling in this model. The ability of tumorigenic cells to withstand growth factor and nutrient deprivation stress (GFDS) is widely regarded as a key attribute for tumor formation and progression. We hypothesized that increased tumorigenicity of FET/DNRII cells was due to loss of participation of autocrine TGFβ in a “fail-safe” mechanism to generate cell death in response to this stress. Here, we document that loss of autocrine TGFβ in FET/DNRII cells resulted in greater endogenous cell survival in response to GFDS due to activation of the phosphoinositide 3-kinase (PI3K)/Akt/survivin pathway. Treatment of FET DNRII cells with a PI3K inhibitor (LY294002) inhibited Akt phosphorylation and reduced survivin expression resulting in increased apoptosis in FET/DNRII cells. We also show that exogenous TGFβ increased apoptosis in FET cells through repression of the PI3K/Akt/survivin pathway during GFDS. These results indicate that the PI3K/Akt/survivin pathway is blocked by TGFβ signaling and that loss of autocrine TGFβ leads to increased cell survival during GFDS through the novel linkage of TGFβ-mediated repression of survivin expression. Inhibition of survivin function by dominant-negative approaches showed that this inhibitor of apoptosis family member is critical to cell survival in the FET/DNRII cells, thus indicating the importance of this target for TGFβ-mediated apoptosis. [Cancer Res 2008;68(9):3152–60]
Data from The Kringle 1 Domain of Hepatocyte Growth Factor Has Antiangiogenic and Antitumor Cell Effects on Hepatocellular Carcinoma
Authors: Shen Zan , Yang Zhen Fan , Gao Yi , Li Ji Cheng , Chen Hai Xiao , Liu Ching Chiu , Poon Ronnie T.P. , Fan Sheung Tat , Luk John M. , Sze Kong Hung , Li Tsai Ping , Gan Ren Bao , He Ming Liang , Kung Hsiang Fu , Lin Marie C.M.
Published: March 2024

Abstract
The kringle 1 domain of human hepatocyte growth factor (HGFK1) was previously shown to inhibit bovine aortic endothelial cell proliferation, suggesting that it might be an antiangiogenic molecule. Here, we evaluated the in vivo efficacy of a recombinant adenoassociated virus carrying HGFK1 (rAAV-HGFK1) for the treatment of hepatocellular carcinoma (HCC) in a rat orthotopic HCC model and explored its molecular mechanisms in vitro in both endothelial and tumor cells. We first showed that rAAV-HGFK1 treatment significantly prolonged the survival time of rats transplanted with tumor cells. Treatment with rAAV-HGFK1 inhibited tumor growth, decreased tumor microvessel density, and completely prevented intrahepatic, lung, and peritoneal metastasis in this in vivo model. In vitro, rAAV-HGFK1 exhibited both antiangiogenic and antitumor cell effects, inhibiting the proliferation of both murine microvascular endothelial cells (MEC) and tumor cells, and inducing apoptosis and G0-G1 phase arrest in these cells. To our surprise, rAAV-HGFK1 did not act through the hepatocyte growth factor/hepatocyte growth factor receptor pathway. Instead, it worked mainly through epidermal growth factor (EGF)/epidermal growth factor receptor (EGFR) signaling, with more minor contributions from vascular endothelial growth factor/vascular endothelial growth factor receptor and β fibroblast growth factor (bFGF)/β fibroblast growth factor receptor (bFGFR) signaling. In both MECs and tumor cells, rAAV-HGFK1 acted through two pathways downstream of EGFR, namely inhibition of extracellular signal-regulated kinase activation and stimulation of p38 mitogen-activated protein kinase/c-Jun-NH2-kinase activation. These results suggest for the first time that HGFK1 exerts both antiangiogenic and antitumor cell activities mainly through EGF/EGFR signaling, and may thus be considered as a novel therapeutic strategy for the treatment of HCC. [Cancer Res 2008;68(2):404–14]