bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1004: Hedgehog signaling promotes tumor vascularization, growth and metastasis of breast cancer via upregulation of CYR61
Authors: Harris Lillianne G. , Pannell Lewis K. , Samant Rajeev S. , Shevde Lalita A.
Published: June 2012

Several clinical trials have used chemotherapeutic drugs that specifically target vascular endothelial cell growth factor (VEGF). Although these trials have demonstrated significant improvements in response rates, findings to date have not indicated substantial benefits in terms of survival. This is likely to be due to the ability of tumor cells to utilize several alternative pathways to establish vasculature. Hence, there is an urgent need to define and target other active pathways that contribute to angiogenesis, such that the vascularity of the tumor can be effectively reduced.

Hedgehog (Hh) signaling, which promotes cell growth and vascularization during fetal development, is activated in several cancers and has been implicated to play a role in promoting cancer progression. We have investigated the role of Hh signaling in impacting tumor malignancy by promoting tumor vascularity. We engineered sonic hedgehog (SHH)-deficient, tumorigenic breast cancer lines, MDA-MB-231 and MCF10AT, to ectopically express the Hh activating ligand, SHH such that the pathway is constitutively activated. Upregulation of SHH-mediated signaling results in the acquisition of enhanced malignant behavior in vitro (increased growth, invasion, migration, and anchorage independent growth) and in vivo (increased tumor take rate and rapidly growing tumors). Furthermore, the SHH expressing cells are able to enhance migration, invasion and network formation of endothelial cells in vitro and elicit increased vasculature in tumor xenografts, in vivo. Using mass spectrometry-mediated analysis of the secretome of the breast cancer cells with constitutive Hh signaling, we identified CYR61 (cysteine-rich angiogenic inducer 61) as a potential mediator of the angiogenic effects of breast cancer cells. Further, our studies show that CYR61 plays a critical role in mediating the vasculature-enhancing effects of breast cancer cells. Taken together, our lab has identified a robust contributor of tumor vascularization which may be an effective VEGF-independent anti-vascularization therapeutic target.

We acknowledge grant support from the Department of Defense-Breast Cancer Research Program (07-1-0400).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1004. doi:10.1158/1538-7445.AM2011-1004
Abstract 1010: Chronic nicotine inhibits apoptosis induced by chemotherapeutic drugs in pancreatic ductal adenocarcinoma (PDAC)
Authors: Banerjee Jheelam , Al-Wadei Hussein A. N. , Schuller Hildegard M.
Published: June 2012

Smoking is an established risk factor for pancreatic cancer. More than 95% of all pancreatic cancers are pancreatic ductal adenocarcinomas (PDACs). Our data has earlier established that nicotine contributes to the progression of smoking associated PDAC by increasing the systemic levels of the stress neurotransmitters adrenaline and noradrenaline in pancreatic cancer xenografts. These findings suggested that development and progression of PDAC is subject to significant modulation by stimulatory stress neurotransmitters. Here we demonstrate that nicotine abrogates the apoptotic activity of gemcitabine, gefitinib, and meloxicam, which are standard therapy for PDAC, in a variety of human PDAC cell lines. We first evaluated the effect of gemcitabine, gefitinib and meloxicam on cell proliferation using a varied range of concentrations and timepoints on pancreatic cancer cell lines PANC-1 and BXPC-3. The results demonstrated that all the three anti-cancer drugs significantly inhibited the proliferation of pancreatic cancer cells PANC-1 and BXPC-3. The IC50 values were determined for optimal concentration and timepoint. It was next examined whether chronic nicotine could confer protection against apoptosis induced by gemcitabine, gefitinib, and meloxicam, which are widely used to treat PDAC. Cells were stimulated with 1 µM nicotine (pre-determined concentration) in the presence or absence of the IC50 concentrations of the indicated drugs. Our results indicated that nicotine suppresses apoptosis induced by gemcitabine, gefitinib, and meloxicam in pancreatic cancer cells, as measured by TUNEL assays, viability assays and western blotting of apoptosis associated proteins. In conclusion, the antiapoptotic effects of nicotine, negatively impacts the chemosensitivity of PDAC cells against anticancer drugs. These findings suggest that continued exposure to nicotine during cancer therapy may significantly reduce the responsiveness to anti-cancer agents.

This work is supported by grants RO1CA130888 and RO1CA042829 with the National Cancer Institute.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1010. doi:10.1158/1538-7445.AM2011-1010
Abstract 1012: Osteopontin mediates loss of tumor suppressive activity of Merlin in breast cancer
Authors: Morrow K. Adam , Metge Brandon J. , Das Shamik , Ye Keqiang , Mulekar Madhuri S. , Tucker J. Allan , Samant Rajeev S. , Shevde Lalita A.
Published: June 2012

The neurofibromatosis type 2 (NF2) tumor suppressor gene encodes a cytoskeletal/membranous protein, Merlin. Inactivation of the NF2 gene is known to cause tumors of the nervous system in humans and multiple cancers in mice. Although Merlin's role as a tumor suppressor has been well studied in other systems, its function in breast cancer is unknown.

In this study, we have determined that the expression of Merlin protein is decreased in breast cancer tissues. Concomitantly, we observed increased expression of osteopontin (OPN), a malignancy-promoting protein that induces activation of Akt phosphorylation. Thus, there is an inverse correlation between the expression of Merlin and OPN in breast cancer. Ectopic restoration of Merlin in breast cancer cells significantly reduced attributes of malignant behavior as assessed in vitro by foci formation, soft agar colony formation, and invasion. In vivo, breast cancer cells stably expressing Merlin displayed reduced tumor growth and progression in athymic mice. Further, our investigations reveal that OPN-initiated activation of Akt signaling results in phosphorylation of Merlin at Serine 315 that targets it for proteasome-mediated degradation.

Thus, our studies elucidate the utility of Merlin as an important biomarker in breast cancer and also identify a novel mechanism for the loss of Merlin expression in breast cancer. Moreover, our studies demonstrate the ability of Merlin to act as a tumor suppressor in breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1012. doi:10.1158/1538-7445.AM2011-1012
Abstract 1014: Induction of human steroid sulfatase by TNF-α through PI3-K/Akt signaling pathway in PC-3 human prostate cancer cells
Authors: Chun Young-Jin , Suh Bo-Young , Park Na-Hee , Jung Jin-Joo , Kim Donghak
Published: June 2012

Steroid sulfatase (STS) is responsible for the hydrolysis of aryl and alkyl steroid sulfates and has a pivotal role in regulating the formation of biologically active estrogens. STS may help support the growth of hormone-dependent cancers, including prostate cancers and is considered as a new promising drug target for treating estrogen-mediated cancer. However, the molecular mechanism of STS expression is still not well-known. Previously, cytokines such as TNF-α and IL-6 were known to increase the activity of STS but the changes in expression have not been completely elucidated. To investigate whether cytokines are able to regulate transcription of STS gene, we studied the effect of TNF-α on STS expression in human prostate cancer PC-3 cells. Western blot and RT-PCR analyses showed that treatment with TNF-α significantly induced expression of mRNA level and protein level of STS in concentration- and time-dependent manners. Treatment with TNF-α resulted in a strong increase in the phosphorylation of Akt on Ser 473 and when the cells were treated with PI3-K inhibitors such as LY294002 or wortmannin or Akt inhibitor (Akt inhibitor IV) together, STS expression induced by TNF-α was significantly blocked. Moreover, inhibition of Akt activation by transfecting dominant-negative Akt plasmid also prevented TNF-α -mediated STS gene expression. Taken together, these data strongly suggest that TNF-α induces STS expression through PI3-K/Akt signaling pathway in PC-3 cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1014. doi:10.1158/1538-7445.AM2011-1014
Abstract 1017: Phosphorylation of histone H2AX at Ser139 and a new phosphorylation site Ser16 by RSK2 decreases H2AX ubiquitination and inhibits cell transformation
Authors: Zhu Feng , Zykova Tatyana , Peng Cong , Zhang Jishuai , Cho Yong-Yeon , Zheng Duo , Yao Ke , Ma Wei-Ya , Lau Andy T.Y. , Bode Ann M. , Dong Zigang
Published: June 2012

Histone H2AX is a histone H2A variant that is ubiquitously expressed throughout the genome. It plays a key role in the cellular response to DNA damage and has been designated as the histone guardian of the genome. H2AX deficiency decreases genomic stability and increases tumor susceptibility of normal cells and tissues. However, the role of H2AX phosphorylation in malignant transformation and cancer development is not totally clear. We found that ribosomal S6 kinase 2 (RSK2) directly phosphorylates H2AX at Ser139 and also at a newly discovered site, Ser16. EGF-induced phosphorylation of H2AX at both sites was decreased in RSK2 knockout cells. Phosphorylated RSK2 and H2AX co-localized in the nucleus following EGF treatment and the phosphorylation of H2AX by RSK2 enhanced the stability of H2AX and prevented cell transformation induced by EGF. RSK2 and DNA-PK, but not ATM or ATR, are required for EGF-induced phosphorylation of H2AX at Ser139. However, only RSK2 is required for phosphorylation of H2AX at Ser16. Phosphorylation of histone H3 was suppressed in cells expressing wildtype H2AX compared with H2AX knockout (H2AX-/-) cells. EGF-associated AP-1 transactivation activity was dramatically lower in H2AX-/- cells overexpressing wildtype H2AX compared with H2AX-/- cells expressing mutant H2AX-AA. Thus, the RSK2/H2AX signaling pathway negatively regulates the RSK2/histone H3 pathway and therefore maintains normal cell proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1017. doi:10.1158/1538-7445.AM2011-1017
Abstract 1026: Correlation of complex signaling pathway interactions with cell migration in a combined phosphorylation-cell migration assay
Authors: Chen Huaxian , Draney Daniel , Olive Michael
Published: June 2012

The acquisition of the ability of a cell to migrate, a process critical to tumor progression, is dependent on the activation of key cell signaling pathways. Screening assays that simultaneously quantify cell migration and the activity of the underlying signaling kinases may facilitate more efficient drug development. We report here an assay that allows simultaneous assessment of cell migration and pathway activity. The assay was performed in a commercially available microtiter plate and used near-infrared detection to achieve high sensitivity and reproducible results. The quality of the assay as determined by Z-factor analysis was 0.7 for migration and 0.58 for detection of phosphorylation. To model the drug screening process, we examined the effects of inhibitors of IGF-1R, PDGFR, and EGFR on cell migration and phosphorylation of AKT and ERK. An IGF-1R inhibitor strongly decreased both cell migration and phosphorylation of AKT and ERK. A PDGFR inhibitor showed a similar effect, but to a lesser degree. Inhibitors of PI-3 kinase/AKT and MEK also decreased cell migration but had surprising effects on the phosphorylation of AKT and ERK. Inhibition of MEK reduced phosphorylation of ERK to undetectable levels, yet did not completely abolish cell migration. Instead, AKT phosphorylation increased significantly. Likewise, inhibition of AKT decreased but did not abolish migration and increased ERK phosphorylation. The combination assay effectively assessed both migration and pathway activity as well as pathway crosstalk, a feature that should be useful for drug development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1026. doi:10.1158/1538-7445.AM2011-1026
Abstract 1028: Hypoxia induces Notch signaling and promotes breast cancer metastasis by stimulating growth and self renewal of cancer stem-like cells
Authors: Xing Fei , Okuda Hiroshi , Watabe Misako , Kobayashi Aya , Pai Sudha K. , Liu Wen , Pandey Puspa R. , Fukuda Koji , Hirota Shigeru , Sugai Tamotsu , Wakabayashi Go , Koeda Keisuke , Kashiwaba Masahiro , Suzuki Kazuyuki , Chiba Toshimi , Endo Masaki , Watabe Kounosuke
Published: June 2012

Notch signaling is often and aberrantly activated by hypoxia during tumor progression; however, the exact pathological role of hypoxia-induced Notch signaling in tumor metastasis is as yet poorly understood. In this study, we aimed to define the mechanism of Notch ligand activation by hypoxia in both primary tumor and bone stromal cells in the metastatic niche and to clarify their roles in tumor progression. We have analyzed the expression profiles of various Notch liagnds in 779 breast cancer patients in GEO database and found that the expression of Jagged2 among all five ligands is most significantly correlated with the overall- and metastasis-free survival of breast cancer patients. The results of our immunohistochemical (IHC) analysis for Jagged2 in 61 clinical samples also revealed that both Jagged2 and Notch signaling were strongly up-regulated at the hypoxic invasive front. Activation of Jagged2 by hypoxia in tumor cells induced EMT and also promoted cell survival in vitro. Notably, a γ-secretase inhibitor significantly blocked Notch-mediated invasion and survival under hypoxia by promoting expression of E-cadherin and inhibiting AKT phosphorylation. Importantly, Jagged2 was also found to be up-regulated in bone marrow stroma under hypoxia and promoted the growth of cancer stem-like cells by activating their Notch signaling. Therefore, hypoxia-induced Jagged2 activation in both tumor invasive front and normal bone stroma plays a critical role in tumor progression and metastasis, and Jagged2 is considered to be a valuable prognostic marker and may serve as a novel therapeutic target for metastatic breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1028. doi:10.1158/1538-7445.AM2011-1028
Abstract 1044: Role of autophagic mediators in the transition from endometriosis to endometriosis-associated ovarian cancers
Authors: Bauckman Kyle A. , Flores Idhaliz , Nanjundan Meera
Published: June 2012

Endometriosis, a common painful and inflammatory gynecological disease, has been proposed to contribute to the development of endometriosis-associated ovarian cancer, specifically the endometrioid and clear cell subtypes. The mechanism underlying this transition is unclear; however, many characteristics of endometriosis and endometrioid-ovarian cancer are similar with the exception of loss of cell cycle control. Autophagy, a survival mechanism which is activated in response to multiple stresses promotes tumorigenic development and may be an ideal target for therapy. To date, the role of autophagy in the development of endometrioid-ovarian carcinomas is unknown with the exception of attenuated mRNA levels of the autophagic marker, beclin-1, in an endometriosis-related condition. Since we have shown that SnoN/SkiL, a TGFβ co-transcriptional regulator, modulates autophagy in ovarian cancer cell lines, we propose that SnoN and/or autophagic mediators may be involved in the transition from endometriosis to ovarian cancer. Thus, we determined the basal expression levels of markers of TGFβ and autophagic pathways in primary and SV40 LTg immortalized endometriotic cells isolated from patients with endometriosis and compared their levels to endometrial/ovarian carcinoma cell lines. Cell lysates were prepared from confluent cultures of (1) five endometrial carcinoma cell lines (MFE296, MFE319, AN3-CA, KLE, and HEC-1A), (2) endometrioid-ovarian carcinoma cell line (TOV112D), (3) a clear cell carcinoma cell line (TOV21G), (4) three serous epithelial ovarian carcinoma cell lines (OVCAR8, HEY, and SKOV3), and (5) two primary (PNEs) as well as four SV40 LTg immortalized (INEs) normal endometriotic cells (derived from patients with endometriotic lesions). These were then assessed for protein expression levels of markers in various signaling pathways (autophagy, TGFβ, cell survival, and epithelial-mesenchymal transition) via western analysis and densitometric analysis. Relative to endometrial/serous epithelial ovarian carcinomas, PNEs and INEs expressed (1) low levels of oncogenes (EVI1, SnoN, and EGFR), (2) elevated levels of tumor suppressors (PTEN), (3) elevated levels of the EMT marker N-Cadherin, and (4) low levels of autophagic markers (i.e. ATG5, ATG7, and hVps34). Since we have observed marked differences in expression of autophagy and TGFβ signaling mediators, studies are ongoing to investigate the effects of knockdown and overexpression of ATGs and SnoN/SkiL in TOV112D and INEs, respectively, to determine their role in modulating this transition event.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1044. doi:10.1158/1538-7445.AM2011-1044
Abstract 1052: In vitro mechanism of action of AZD5363, a novel AKT inhibitor, in breast and prostate cancer cell lines
Authors: Greenwood Hannah , Crafter Claire , Davies Barry , Cosulich Sabina
Published: June 2012

AKT (protein kinase B) is a key regulator of the phosphoinositide-3-kinase signaling pathway and plays a key role in mediating signals for cell growth, survival and differentiation. This pathway is among the most commonly de-regulated pathways in human cancer and represents a key target for therapeutic intervention. Here, we describe the in-vitro mechanism of action of AZD5363, a potent small molecule inhibitor of AKT1, AKT2 and AKT3. We show that treatment of breast and prostate cancer cell lines with AZD5363 leads to inhibition of phosphorylation of a number of AKT substrates including PRAS40, GSK-3β and the downstream marker, P70S6K. In the BT474c cell line, >90% inhibition of phosphorylation of PRAS40 was observed at 1uM and this effect was sustained for 24 hours. Inhibition of phosphorylation of 4E-BP1, a key regulator of protein translation, was also observed when treating cells with AZD5363. We demonstrate that inhibition of phosphorylation of 4EBP1 (Thr37/46) is associated with an induction of 4E-BP1 binding to the eIF4E-mRNA CAP complex within 1 hour of dosing with AZD5363, consistent with inhibition of CAP-dependent protein translation. Analysis of phenotypic endpoints indicates that AZD5363 is a potent inhibitor of proliferation in the majority of breast and prostate cell lines studied. In addition, in a subset of cell lines, treatment with AZD5363 was shown to induce a cytotoxic phenotype measured by a Sytox Green endpoint. In the BT474c cell line, 1uM AZD5363 inhibited phosphorylation of 4E-BP1 by 50% at 24 hours and induced 11% apoptosis at 72 hours. This data demonstrates that AZD5363 has profound effects on downstream effectors of the PI3K/AKT pathway consistent with that of an Akt inhibitor which results in an anti-proliferative, and in some cases cytotoxic, profile in breast and prostate cell lines. AZD5363 is currently in Phase I clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1052. doi:10.1158/1538-7445.AM2011-1052
Abstract 1059: Altered LKB1/CREB-regulated transcription co-activator (CRTC) signaling axis promotes esophageal cancer cell migration and invasion
Authors: Gu Yumei , Lin Shuibin , Li Jian-Liang , Nakagawa Hiroshi , Chen Zirong , Tian Liang , Ucar Deniz A. , Shen Huangxuan , Lu Jianrong , Hochwald Steven N. , Kaye Frederic J. , Wu Lizi
Published: June 2012

Esophageal cancer is one of the most common malignancies and leading causes of cancer deaths worldwide. Esophageal squamous cell carcinoma accounts for the majority of esophageal cancers but in recent years the incidence of esophageal adenocarcinoma has increased dramatically, particularly in Western countries. Esophageal cancers are highly invasive and metastatic, which account for the high rate of cancer death. However, the exact molecular mechanisms that contribute to the initiation and progression of esophageal cancer remain unclear. LKB1 is a tumor susceptibility gene for the Peutz-Jeghers cancer syndrome (PJS) and is a target for mutational inactivation in sporadic human malignancies. LKB1 encodes a serine/threonine kinase that plays critical roles in cell growth, polarity and metabolism. A novel and important function of LKB1 is its ability to regulate the phosphorylation of CREB-regulated transcriptional co-activators (CRTC) whose aberrant activation is linked with oncogenic activities. However, the roles and mechanisms of LKB1 and CRTC in the pathogenesis of esophageal cancer have not been previously investigated. In this study, we observed altered LKB1-CRTC signaling in a subset of human esophageal cancer cell lines and patient samples. LKB1 negatively regulates esophageal cancer cell migration and invasion in vitro. Mechanistically, we determined that CRTC signaling becomes activated due to LKB1 loss, which results in the transcriptional activation of specific downstream targets including LYPD3, a critical mediator for LKB1-loss of function. Our study indicates that de-regulated LKB1-CRTC signaling might represent a crucial mechanism for esophageal cancer progression. Our data warrant future studies to understand the importance of LKB1 and CRTC signaling in esophageal cancers and to investigate CRTC activation as a target for cancers with LKB1 down-regulation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1059. doi:10.1158/1538-7445.AM2011-1059
Abstract 1064: Pim serine/threonine kinases regulate the phosphorylation and function of eIF4B protein
Authors: Chen Jilong , Wang Jun , Yang Jianling
Published: June 2012

Eukaryotic initiation factor 4B (eIF4B) is a multidomain protein with a critical role in the initiation of protein synthesis, and has long been known as a hyperphosphorylated protein. It has been thought that function of eIF4B can be regulated by phosphorylation. The Pim family of Ser/Thr kinase, which is consisted of three members: Pim-1, Pim-2, and Pim-3, has been implicated in multiple cellular processes including cellular survival, anti-apoptosis and tumorigenesis. In this study, we identified eIF4B as a Pim kinase substrate. We found that Pim-1, Pim-2 but not Pim-3 can upregulate phosphorylation levels of eIF4B on Ser406 and Ser422 using 293T cell system, while kinase-dead mutants of Pim-1 or Pim-2 significantly inhibit phosphorylation of eIF4B. Furthermore, in vitro kinase assay revealed that Pim-1 kinase can directly phosphorylate eIF4B on Ser422. As expected, we found that Pim-1 kinase directly bound to eIF4B using GST-pull down assay and co-immunoprecipitation experiments. Interestingly, levels of eIF4B protein in v-Abl transformants treated with the Abl kinase inhibitor imatinib decreased markedly, indicating that expression of eIF4B is Abl kinase dependant. Our results suggest that Pim kinases regulate cellular processes via phosphorylating downstream eIF4B, and thereby alter the function of eIF4B in v-Abl transformants. Together, these data possibly provide new insights into molecular mechanisms of Abl oncogene-mediated cellular transformation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1064. doi:10.1158/1538-7445.AM2011-1064
Abstract 1076: Activation of H-Ras and Rac1 correlates with epidermal growth factor-induced breast cell invasion
Authors: Koh Min-Soo , Kim Sun-Young , Lim Do Young , Moon Aree
Published: June 2012

There are considerable experimental evidences that hyperactive Ras proteins promote breast cancer growth and development including invasiveness despite of low frequency of mutated forms of Ras in breast cancer. We have previously shown that H-Ras, but not N-Ras, induces an invasive phenotype mediated by small GTPase Rac1 in MCF10A human breast epithelial cells. Epidermal growth factor (EGF) plays important roles in aberrant growth and metastasis formation of many tumor types including breast cancer. Here, we investigated the involvement of H-Ras in the EGF-induced invasive ability of four different breast cancer cell lines. Upon EGF stimulation, H-Ras activation was increased in the invasive breast cancer cells, MDA-MB-231 and Hs578T cells, but not in non-invasive breast cancer cells, MDA-MB-453 and T47D cells. Using small interfering RNA (siRNA) targeting H-Ras, we showed a crucial role of H-Ras in invasive phenotype induced by EGF in MDA-MB-231 and Hs578T cells. Moreover, knockdown of Rac1significantly inhibited the EGF-induced invasiveness in these cells. Taken together, our data demonstrate that the activation of H-Ras and its downstream molecule Rac1 correlates with breast cancer cell invasion induced by EGF, providing useful information on the regulation of malignant progression in mammary carcinoma. [This work was supported by the Korea government (Nos.ROA-2008-000-20070-0)]

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1076. doi:10.1158/1538-7445.AM2011-1076
Abstract 1084: c-Crk proto-oncogene and TGF-β signaling pathway contribute to transcriptional repression of p120-catenin in non-small cell lung cancer cells
Authors: Mortazavi Fariborz (Fred) , Dubinett Steven M. , Rettig Matthew B.
Published: June 2012

As a member of adherens junction, p120-catenin (p120ctn) plays a major role in cell adhesion through stabilization of E-cadherin. p120ctn is transcriptionally down-regulated in non-small cell lung cancer (NSCLC), although the molecular mechanisms underlying p120ctn repression are incompletely defined. Here we further investigated transcriptional regulation of p120ctn in NSCLC. We prepared a promoter reporter plasmid construct that contained p120ctn promoter region from position -1082 to +320 relative to transcription start site. Through serial deletion mutation analysis of the p120ctn promoter, we pinpointed cis-acting elements involved in regulation of p120ctn. We identified transcription factor SP1 as a transcriptional repressor of p120ctn that directly binds to segment (−9 to +36) of the p120ctn promoter. SP1 can receive multiple signals from several intracellular signaling pathways. Through examination of SP1 binding partners, we identified proto-oncogene c-Crk and TGF-β signaling pathway to be involved in transcriptional down-regulation of p120ctn. RNAi mediated silencing of CRK in A549, H157 and H358 cells increased p120ctn protein levels. On the other hand, over-expression of CRK-I in H358 cells down-regulated p120ctn, an effect that was abrogated by simultaneous silencing of SP1. We also observed that CRK-II serine phosphorylation was inversely correlated with p120ctn expression level. This finding suggests a role for serine/threonine kinases in promoting metastasis through phosphorylation of CRK I/II and subsequently down-regulation of p120ctn. In summary, our data provide evidence for the role of c-Crk proto-oncogene and TGF-β signaling in transcriptional repression of p120ctn that further clarifies the mechanism by which these biochemical signals promote metastasis in NSCLC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1084. doi:10.1158/1538-7445.AM2011-1084
Abstract 109: DNA methylation profiling associated with recurrence of prostate cancer
Authors: Donkena Krishna Vanaja , Klee Eric W. , Young Charles Y.F. , Klee George G. , Tindall Donald J. , Blute Michael L.
Published: June 2012

DNA methylation profiles could signify the risk of prostate cancer and predict the progression of cancer before the appearance of clinical symptoms. Specific CpG sites methylation of genes identified in our study could be used to improve the sensitivity and specificity for early diagnosis and to predict the risk of prostate cancer recurrence. To identify methylation changes associated with prostate cancer, we measured gene methylation using the Infinium Human Methylation27 bead chips. Tissue DNA isolation and bisulfite conversion was done using ZR Genomic DNA kit and EZ methylation kit. The methylation27 microarrays was used to analyze methylation of 27,578 CpG sites of 14,495 genes in 198 tumor tissues and 40 matched normal tissues. Methylation data was processed using the Genome Studio software, differentially methylated genes identified using one-way analysis of variance, and correction for multiple testing done using the false discovery rate q-value. To identify putative diagnostic and prognostic biomarkers we performed four subgroup comparisons: tumor vs. matched normal, recurrent tumors vs. non-recurrent tumors, clinical recurrence vs. biochemical recurrence, and systemic recurrence vs. local recurrence. Clinicopathological and molecular features including patient preoperative PSA levels, Gelason score, TNM stage, GPSM, recurrence type, were also evaluated for subgroup discrimination. Discriminative subgroup candidate methlyation markers were selected using a p value <0.05 and a mean difference between two contrast groups >0.05. Between the tumor and matched normal tissue samples, 164 CpG sites representing 147 genes were identified as significantly differentially methylated (p<9.99E-25, fold change>2.0). Between recurrent tumor and non-recurrent tumor tissues there were 78 CpG sites representing 75 genes that were significantly differentially methylated (p <0.002, fold change >1.5). Between clinically recurrent and biochemically recurrent tumors, 16 CpG sites representing 16 genes were significantly differentially methylated (p <0.05, fold change >1.5). Between systemic recurrent and local recurrent tumors there were 73 CpG sites representing 68 genes that were significantly differentially methylated (p <0.01, fold change >1.5) Our analysis revealed differential methylation of the genes, implicating their role in prostate cancer development and progression. We demonstrated that the hypermethylation of genes could be used as a sensitive molecular tool in detection of prostate tumorigenesis and prediction of tumor progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 109. doi:10.1158/1538-7445.AM2011-109
Abstract 1093: BioMAP® profiling in primary human cell systems as a tool for drug discovery in inflammation and cancer
Authors: O'Mahony Alison M. , Melrose Jennifer , Privat Sylvie , Alajoki Liisa , Nguyen Dat , Polokoff Mark , Plavec Ivan , Berg Ellen
Published: June 2012

It is now widely accepted that chronic inflammatory events are critical contributors to both the development and progression of cancer. While the complex interrelationship between immune events and their effects on the neoplastic process remain to be defined, targeting inflammation has now become a priority of drug discovery in oncology. A major factor propelling this strategy is that both cancer cells and immune cells share many common signaling pathways that can contribute to the disease promoting microenvironment of the tumor. Drugs that target these pathways now make up a significant portion of pharmaceutical pipelines but how these compounds affect cancer cells, normal tissues and immune processes remains poorly understood. In order to develop more effective therapeutic strategies it is imperative that we understand the biological impact of compounds that target key signaling intermediates on normal and immune cells as well as neoplastic cells. BioSeek has pioneered the development of in vitro human cell-based systems (BioMAP® Systems) that recapitulate the complex signals and phenotypic responses of inflamed tissues in vivo. In addition to providing broad coverage of inflammatory targets, BioMAP® Systems model modulation of many signaling pathways relevant to cancer. Characterization of pathway-associated kinase inhibitors, including JAK, PI3K, p38MAPK, ERK, JNK and NF-κB in BioMAP® Systems has revealed activities that differentially impact inflammatory, proliferative, angiogenic and tissue remodeling processes. Secondly, profiling of 1000s of off-patent compounds through BioMAP® Systems identified agents that selectively prevent the growth of smooth muscle cells and related cancers (leiomyosarcomas and rhabdomyosarcomas) with little impact on the activation of immune cells. BioMAP® Systems provide a highly useful platform to (1) distinguish anti-inflammatory and anti-proliferative effects of various kinase inhibitors and (2) identify different phenotypic outcomes of these agents that influence cancer progression and disease resolution. Together these data will help inform the selection of more effective therapeutic strategies to target different cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1093. doi:10.1158/1538-7445.AM2011-1093
Abstract 1096: Prostate tumor growth in pbARR2-Cre PTEN knockout mice is delayed in GH/IGF-I deficient mice
Authors: Ibuki Naokazu , Takahara Kiyoshi , Tearle Howard , Gleave Martin E. , Ong Christopher J. , Pollak Michael , Cox Michael E.
Published: June 2012

Growth hormone/insulin-like growth factor I (GH/IGF-I) axis has been related to risk of prostate cancer (PCa). We have previously reported that androgen-responsive, castration-resistant (CR), and androgen-independent (AI) PCa xenografts develop more slowly in little murine hosts. The little (lit/lit) phenotype is due to a D60G missense mutation in the GH-releasing hormone receptor (GHRHR) resulting in loss of pituitary GHRHR function and suppression of GH and IGF-I expression. PTEN is a tumor suppressor gene that is frequently mutated in a variety of spontaneous cancers, including PCa. The prostate-conditional PTEN-null mouse represents the first animal model in which deletion of a single endogenous gene leads to invasive PCa. To investigate the role of GH/IGF-I axis on in vivo prostate carcinogenesis and neoplastic progression, we crossed pbARR2-Cre, PTEN(fl/fl) mice (PTEN-/-) with IGF-I deficient lit mice, and produced lit/lit and lit/+ PTEN-/- mice. To complement the in vivo experiments, in vitro growth and growth factor signaling of murine PTEN-/- cells derived from the prostate (MPPK) or lymph node (MLPK) using serum from lit/lit or lit/+ mice was examined. RESULTS: Body weight and serum GH, IGF-I levels of lit/lit PTEN-/- mice were significantly reduced as compared with lit/+ PTEN-/- mice. At 15 weeks of age, prostate cancer progression of lit/lit PTEN-/- mice was partially delayed as compared with lit/+ PTEN-/- mice. MPPK and MLPK cells growth in vitro with serum from lit/lit mice showed decreased proliferation as compared with serum from lit/+ mice. Suppressed growth in lit/lit serum could be restored by addition of IGF-I, and to a lesser extent, GH. Addition of GH or IGF-I to lit/lit serum increased only activation of AKT while no change in ERK1/2 activation was detected in MPPK cells. Our in vivo and in vitro results suggest that prostate carcinogenesis may be influenced by germ line variation of genes encoding signaling molecules in the GH/IGF-I axis and support the continued development of clinical trials of novel hormonal treatment strategies that target the GH/IGF-I axis for PCa patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1096. doi:10.1158/1538-7445.AM2011-1096
Abstract 1100: Correlation of basic fibroblast growth factor and cyclooxygenase-2 activity in non-small lung cancer cells
Authors: Fulson-Woytek Michael J. , Valenta David A. , Baguma-Nibasheka Mark
Published: June 2012

Basic fibroblast growth factor (FGF-2) is a potent wide-spectrum mitogen and the dysregulation of its expression is associated with cell proliferation and immortalization in a wide variety of tumors. Its oncogenic nature may depend, in part, on its ability to prevent apoptosis. Its antisense gene, NUDT6, encodes a novel Nudix motif protein of unknown function, and overexpression of NUDT6 is known to suppress FGF-dependent cell proliferation (Baguma-Nibasheka et al, Mol Cell Endocrinol 267:127-136, 2007). Cyclooxygenase-2 (COX-2) is a key enzyme in prostaglandin synthesis whose up-regulation has been implicated in the promotion of lung cancer. COX-2 inhibition suppresses growth and induces apoptosis in human non-small cell lung cancer (NSCLC) cells. In this study, we evaluated the hypothesis that the antitumor activity of COX-2 inhibitors in lung cancer may involve modulation of FGF-2, which is overexpressed in NSCLC. Results: FGF, NUDT6 and COX-2 are co-expressed in NSCLC cells, and FGF-2 and COX-2, but not NUDT6 messenger RNA levels, as well as cell proliferation, are decreased by serum deprivation. Selective inhibition of COX-2 suppresses FGF-2 but not NUDT6 expression, and FGF-2 knockdown negates the effect of COX-2 inhibition on cell proliferation. These findings indicate that the antitumor effects of COX-2 inhibition in NSCLC may be mediated via suppression of FGF-2. Supported by the Frostburg State University of Biology Department.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1100. doi:10.1158/1538-7445.AM2011-1100
Abstract 1103: Expression profile and role of thromboxane synthase in NSCLC: Correlation with tumor angiogenesis and patient survival
Authors: Cathcart Mary-Clare , Gately Kathy , Kay Elaine , Reynolds John V. , O’ Byrne Kenneth J. , Pidgeon Graham P.
Published: June 2012

Introduction: Thromboxane synthase metabolizes PGH2 into thromboxanes, which are biologically active on cancer cells. TXS over-expression is frequently reported in cancers, and has previously been associated with VEGF and a poor prognosis. TXS blockade inhibits angiogenesis and induces tumor cell death, providing a rationale for intervention. This study aimed to determine the expression profile of TXS, its link to tumor angiogenesis, and if it is prognostic and/or a survival factor in NSCLC.

Methods: TXS expression was examined in human NSCLC samples (protein and tissue) and matched controls by western analysis and IHC. TXS metabolite levels were measured in human NSCLC plasma samples and age-matched controls by EIA. TXS metabolite levels were correlated with VEGF. A 200-patient NSCLC TMA was stained for TXS, VEGF, and CD-31. Staining was correlated with clinical parameters, including 5-year patient survival. TXS expression pattern was correlated with angiogenic markers, VEGF and CD-31 (microvessel density). Stable TXS over-expressing clones were generated and their effect on tumor growth was examined both in-vitro (BrdU) and in-vivo (xenograft mouse model).

Results: TXS was over-expressed in human NSCLC samples, relative to matched controls. Increased TXS and TXB2 levels were observed in protein and plasma samples respectively. TXB2 levels were significantly (p<0.05) correlated with VEGF, while both TXB2 and VEGF levels were higher in adenocarcinoma. Both TXS and VEGF tissue expression were also significantly higher in adenocarcinoma (p<0.001) and female patients (p<0.05). TXS tissue expression was also significantly correlated with that of VEGF (p<0.0001) and CD-31. However, no correlation of TXS with patient survival was observed. Stable TXS over-expression significantly increased tumor cell growth in-vitro and also increased tumor growth in-vivo.

Conclusion: TXS is over-expressed in NSCLC, particularly in the adenocarcinoma subtype and female patients. While TXS was not found to be prognostic, over-expression of this enzyme significantly increased tumor growth both in-vivo and in-vitro, suggesting that TXS promotes tumor survival in NSCLC. Our study also demonstrated a significant correlation of TXS with both VEGF and tumor vessel count, suggesting that the pro-tumor effects of TXS expression are at least partly mediated via tumor angiogenesis. Further studies using in-vivo models will confirm this observation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1103. doi:10.1158/1538-7445.AM2011-1103
Abstract 1107: Transforming growth factor-beta (TGF-β) increases Par-4 expression via activation of Smad and NF-κB in endometrial cancer cells
Authors: Singh Mohan , Chaudhry Parvesh , Asselin Eric
Published: June 2012

Prostate apoptosis response-4 (Par-4) gene was originally identified in prostate cancer cells undergoing apoptosis. Further studies have shown that Par-4 selectively induces apoptosis in cancer cells without effecting normal cells. Recently it has been evidenced that Par-4 has a tumor suppressor role in endometrial cancer. We have previously demonstrated that TGF-β isoforms are expressed in endometrial tumors and determined cellular fate by regulating apoptosis through the activation of NF-κB. In the present study, we have investigated the mechanisms through which TGF-β isoforms regulate Par-4 expression in endometrial cancer cells. KLE and Hec-1-A endometrial cancer cell lines were used as model in this study. Transcript and protein levels were assessed by reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting, respectively. The results revealed that both cell lines express TGF-β receptor I and receptor II. Blocking TGF-β signalling by neutralizing TGF-β antibody reduced endogenous Par-4 mRNA and protein levels. Exogenous treatment with all the TGF-β isoforms (10ng/ml) upregulated Par-4 mRNA and protein levels. Furthermore, there was increase in the levels of phosphorylated Smad2 and Smad3 in response to TGF-β treatment, thus indicating that Smad pathway was activated by TGF-β isoforms in these cells. However, there was no change in the protein levels of total Smad2/3. TGF-β treatment resulted in rapid phosphorylation of IκB-α with no effect on total IκB-α levels thus suggesting an activation, nuclear translocation and increase in transcriptional activity of NF-κB. Collectively, these results suggest that each TGF-β isoform induces Par-4 levels via the activation of Smad and NF-κB pathway in endometrial cancer cells. Since downregulation of Par-4 is a common event in different types of cancers, we suggest in these cases that TGF-β could be an interesting therapy and strategy to induce Par-4 and apoptosis in endometrial cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1107. doi:10.1158/1538-7445.AM2011-1107
Abstract 1108: Ferritin binds breast cancer cells and tissue, and promotes proliferation independently of iron content
Authors: Alkhateeb Ahmed , Connor James
Published: June 2012

A connection between iron and breast tumorigenesis has been convincingly argued over the years. Several in vivo studies have demonstrated that iron-rich diets increase tumor incidence rate in carcinogen-induced mammary tumor models. Moreover, a large cohort study has recently associated mutations in the hemochromatosis (HFE) gene (promoting iron overload) with breast cancer risk in females. Individuals with mutations in the HFE protein can exhibit iron accumulation in the liver, high transferrin saturation levels, and elevated serum ferritin levels, but not have clinical hemochromatosis.

Cells store iron in ferritin, but this protein is also secreted and is detected circulating in serum. Although serum ferritin has been used as an indicator of total body iron, a specific functional role has not been proposed thus far other than perhaps recycling iron to the bone marrow. Interestingly, serum ferritin levels have been shown to be increased in breast cancer patients, and higher levels seem to be associated with poorer prognosis. Furthermore, comparisons between pre- and post-surgery ferritin levels suggested that the tumor itself is responsible for the high levels of serum ferritin possibly through secretion. We have demonstrated that ferritin binds to breast tumor sections obtained from biopsy. Based on these observations, we hypothesized that serum ferritin interacts directly with breast cancer cells enhancing their growth. In this study we report that ferritin exposure will increase proliferation and DNA synthesis in the breast cancer cell lines, MCF-7 and T47D. These effects were not dependent on the iron content of ferritin, as both apo- and holo-ferritin had comparable effects. Because extra-cellular ferritin has been speculated to play an iron delivery role in some cells, we examined changes in transferrin receptor levels, and the quenching of the fluorescent metal-sensitive dye calcein following ferritin treatments. Our data, suggests that ferritin does not deliver iron to cells, and might have an iron-independent signaling function. Taken together, these findings encourage a new perspective on serum ferritin in cancer biology, and raise several possibilities for novel therapeutic and diagnostic strategies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1108. doi:10.1158/1538-7445.AM2011-1108