bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1443: RhoE is underexpressed in hepatocellular carcinoma and suppresses cell motility and invasiveness
Authors: Ma Carmen Wei , Wong Chak-Lui , Wong Irene Chun-Ming , Ng Oi-Lin
Published: June 2012

Hepatocellular carcinoma (HCC) is a major malignancy worldwide and is the second commonest fatal cancer in Southeast Asia and Mainland China including Hong Kong, due to the high prevalence of hepatitis B viral infection. Despite definite improvements in the outcome of patients with HCC, the overall prognosis of this cancer is still unsatisfactory because of late presentation and frequent tumor recurrence after surgical resection. In this regard, knowledge of the molecular and cellular targets underlying the development and progression of liver cancer may provide novel opportunities for therapeutic interventions for this cancer. As part of our continual study on the Rho/ROCK pathway in HCC, in this current study, we aimed to find out the role of RhoE (also known as Rnd3), a member of the Rho family of small GTP-binding proteins, in HCC. We have found that RhoE was frequently underexpressed in 43/71 (60.6%) of our human HCCs at mRNA level using qPCR, as compared with their corresponding non-tumorous livers (p <0.001). Moreover, RhoE knockdown in HCC cells by lentiviral infection of shRhoE enhanced cell migration and invasion in vitro. Using transwell migration assay, we showed that stable shRNA knockdown of RhoE in SMMC7721 and BEL7402 HCC cell lines resulted in faster migration of the cells than their corresponding non-target controls. Moreover, stable RhoE knockdown clones also invaded through the matrigel faster in matrigel invasion assay. Previous studies have indicated that phosphorylation of myosin phosphatase target subunit 1 (MYPT1) at Thr850 was essential for phosphorylation of myosin II and crucial for cell contractility. To further delineate the roles of RhoE on actomyosin contractility, the MYPT1 phosphorylation levels in the Rho stable knockdown transfectants in SMMC, BEL and Hep3B HCC cells were assessed by Western blotting and found to be increased as compared with their non-target control. This increased phosphorylation was reversed by ROCK inhibitor Y27632. Furthermore, the ROCK inhibitor Y27632 was able to suppress the accelerated cell migration brought by the knockdown of RhoE in SMMC, suggesting that RhoE may exert its effects by inhibiting the activity of ROCK1. Since MYPT1 is specifically phosphorylated by ROCK at Thr850, the finding suggests that RhoE interacts with and suppresses the activity of ROCK1 in HCC cells.

To conclude, our data suggest that RhoE in HCC suppresses both cell motility and invasiveness of HCC cells and that RhoE may exert its effects by inhibiting the activity of ROCK1.

(This study was funded by Hong Kong Research Grants Council CRF grants (RGC CRF HKU1/06C and HKU 7/CRG/09)

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 1443. doi:10.1158/1538-7445.AM2011-1443
Abstract 1446: Dissecting the role of PTEN/Akts in metastatic melanoma
Authors: Yu Yanlin , Liu Ziyang , Yu Yixin , Mendoza Arnulfo , Khanna Chand , Merlino Glenn
Published: June 2012

Melanoma is an aggressive human cancer whose incidence is increasing more rapidly than any other cancer in the United States. It is characterized by an extremely high potential to develop metastases and poor response to current therapy. Although the genetic studies indicated that melanoma genesis related with molecular lesions in c-MET, INK4a, Ras/Raf, p53 and PTEN pathways, the molecular mechanism inciting metastatic melanoma are poorly understood. PTEN is a major tumor suppressor in humans. To study the role of PTEN in progression of human melanoma, we first used tissue microarrays to examine PTEN expression in 30 lymph node melanoma metastases, 30 primary melanomas, and 9 normal skin tissues. Our results showed that PTEN loss was significantly correlated with progression to the metastatic state. Moreover, analysis of various human melanoma cell lines demonstrated that PTEN expression was related to metastatic behavior, supporting the notion that PTEN is involved in the metastatic regulation of melanoma. PTEN has phosphatase activity that can act upon both polypeptide and phosphoinositide substrates. The PTEN lipid phosphatase is a ubiquitous regulator of PI3K signaling pathway. The loss of expression or mutational inactivation of PTEN protein enhances the phosphorylation of PKB/AKT and thus influences cell survival signaling. Interestingly, a PTEN mutant, which loses lipid but not protein phosphatase activity, lacks the ability to induce either G1 arrest or apoptosis, but nonetheless retains the ability to inhibit cell spreading and motility, suggesting that PTEN protein phosphatase activity is important for these behaviors. To further dissect the role of this PTEN activity in metastasis, we have established a model system containing exploiting mutant PTEN proteins with various phosphatase activities. We found that wild type PTEN can inhibit cell motility and invasiveness, while PTEN mutants cannot. Notably, wild type PTEN was able to reduce the metastatic potential of melanoma cells, whereas phosphatase deficient PTEN could promote the melanoma cell metastatic behavior. We found that PTEN mediates metastatic activity through the AKT pathway. We further determined that Akt 3 was key mediators of metastatic potential in melanoma cells in vivo. Akt3 could also rescue PTEN-mediated inhibition of metastasis. PTEN loss and Akt3 overexpression functioned synergistically to promote metastasis. Our data demonstrate that metastatic behavior in melanoma cells is dependent on the status of PTEN protein phosphatase activity and downstream Akt3, and suggest that AKT/PTEN signaling should be considered as a therapeutic target in metastatic melanoma

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 1446. doi:10.1158/1538-7445.AM2011-1446
Abstract 1447: An unbiased screen for Nm23-H1 interacting proteins identifies the cytoskeletal crosslinking protein Ezrin
Authors: Marshall Jean-Claude A. , Collins Joshua , Zhou Ming , Veenstra Timothy , Khanna Chand , Steeg Patricia
Published: June 2012

We hypothesized that Nm23-H1 may suppress metastasis through binding and inactivation of proteins that promote aggressive behavior. An unbiased survey of Nm23-H1 binding proteins was conducted in a 4T1 murine mammary carcinoma model system. Flag tagged Nm23-H1 and its mouse variant, -M1, were transfected into 4T1 mouse mammary cancer cells. Clonal lines were inoculated into the number four mammary fat pad of mice and allowed to grow for 10 days prior to excision due to size of the primary tumor. Mice were then imaged weekly for the remainder of the experiment, 8 weeks to follow the metastatic spread of the 4T1 cells from each group. Primary tumor size was unaffected by over-expression of Nm23-H1 or -M1. Histological examination revealed a 75% decrease in liver metastasis by Nm23-H1 or -M1 over-expression (P < 0.001). To characterize Nm23-H1/M1 binding proteins, Flag tagged Nm23 from both H1 and M1 clones were immunoprecipitated (IP) from in vitro cell lines as well as isolated primary tumors, lymph nodes, spleen and liver tissue after verification of metastasis by histological examination of the tissue. Mass spectrometry analysis of IP samples from cell lines and primary tumors showed 99 proteins of interest including Ezrin. Co-IP of Ezrin and Nm23-H1/M1 has been confirmed using both Nm23 and Ezrin as the IP antibodies, implicating Ezrin as a potential binding partner of NM23-H1 and M1. Ezrin belongs to a family of widely expressed proteins known as ERMs which have been described to link the actin cytoskeleton to membrane signaling pathways. To rule out potential interaction due to F-actin, cells were exposed to latrunculin B and co-IP of Nm23-H1 and Ezrin was again verified, indicating that the Ezrin and Nm23-H1/M1 interaction is not due to F-actin binding. To further elucidate this interaction plasmid constructs expressing either the N terminal FERM domain or C terminal F-actin binding domain of Ezrin coupled to GFP were constructed. Co-IP showed a binding of Nm23-H1 to the N terminal domain of Ezrin. In addition the expression of the N terminal overcame the motility and invasive inhibitory phenotype of Nm23-H1 expression in both 4T1 and MDA-MB-231 cells. The data identify a novel interaction of the metastasis suppressor Nm23-H1 and the cytoskeletal linker Ezrin. Suppression of metastasis by Nm23-H1 may be due, in part, to the abrogation of a pro-invasive function of the N-terminus of Ezrin.

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 1447. doi:10.1158/1538-7445.AM2011-1447
Abstract 1451: Inhibition of cell migration via reduced phosphorylation of focal adhesion kinase by TIS21/BTG2/PC3 in A549 cells
Authors: Lim Seo Kyung , Choi Yong Won , Lim In Kyoung , Park Tae Jun
Published: June 2012

It has been reported that TPA inducible sequence 21 (TIS21/BTG2/PC3) functions as a tumor suppressor in carcinogenesis of thymus, prostate, kidney, and liver. Although the expression of TIS21 is down-regulated in primary and metastatic cancers, the role of TIS21/BTG2/PC3 in cell migration and metastasis remains to be elucidated. In this study, we report a role of TIS21 in cancer cell migration. We observed that TIS21 inhibited cell migration and invasion in A549 lung cancer cells. Consistent with this observation, phosphorylation of focal adhesion kinase (FAK) on Y576 and Y925 residues, but not Y397, was markedly inhibited by over-expression of TIS21, which residues are known to be phosphorylated by activated Src. It has been known that activity of Src can be regulated either by phosphorylation at Y416 or oxidation of the molecule. Phosphorylation of Src on Y416 was not regulated by overexpression of TIS21 in A549 cells, whereas TIS21 significantly inhibited Src activity by reducing the generation of reactive oxygen species. In addition to that TIS21 down-regulated matrix metalloproteinase-2 (MMP-2) expression in A549 cells. In summary, therefore, we can suggest that TIS21 down-regulates FAK activity via inhibiting Src activation and reduces expression of MMP-2, resulting in antimetastatic phenomenon in 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 1451. doi:10.1158/1538-7445.AM2011-1451
Abstract 146: The role of Mir-150 as a tumor suppressor in malignant lymphoma
Authors: Tagawa Hiroyuki , Watanabe Atsushi , Sawada Kenichi
Published: June 2012

Disease specific genetic alteration or translocation have not been identified in NK/T cell lymphoma. We recently demonstrated that over expressions of miR-21 and/or miR-155 are frequently occurring in natural killer (NK) cell lymphoma/leukemia and deeply associated with their lymphomagenesis by deregulation of AKT signaling. In this study, we tried to identify tumor suppressor miRNA(s) in malignant lymphomas including B-cell, NK-cell and CD4+T-cell lymphoma, by using quantitative PCR and/or Northern blot analysis. We found that miR-150 in both cell lines and primary samples of NK and T-cell lymphoma showed significantly lower expression than those of normal natural killer cells and CD4+T cells. To examine the role for lymphomagenesis, we stably transduced miR-150 into lymphoma cell lines. Enforced expression of miR-150 in NK/T cell lymphoma cell lines showed increased levels of susceptibility of apoptosis, and showed senescence with reduced levels of telomerase activity and telomere DNA shortening. We further demonstrated that miR-150 directly down regulate AKT2, leading to reduced expression of phosphorylated AKTser473/474 with upregulation of tumor suppressors, Bim, p27 and p53. Since it has been proven that AKT kinase phosphorylate hTERT (human telomerase reverse transcript), downregulation of miR-150 in lymphomas lead to activate telomerase activity, resulting immortalization of the cancer cells. These results suggest that miR-150 play as a role of tumor suppressor in NK/T-cell lymphoma. Our recent and previous report demonstrate that downregulation of miR-150 and upregulation of miR-21/miR-155 collaborately contribute to NK/T-cell lymphomagenesis by deregulating AKT signaling. These findings will give a new insight into the pathogenesis of NK/T cell lymphoma and the miR-150 itself and/or AKT targeting therapy can be a useful against aggressive lymphoma.

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 146. doi:10.1158/1538-7445.AM2011-146
Abstract 1464: Significance and therapeutic potential of PELP1 axis in ER-negative breast cancer
Authors: Vadlamudi Ratna K. , Roy Sudipa Saha
Published: June 2012

The molecular basis of breast cancer progression to metastasis remains poorly understood. Even though ER and PR explain the biology of ER-positive tumors; it remains unknown as to what drives ER-negative metastatic tumors. PELP1 is an ER coregulator that functions as a proto-oncogene, its expression is deregulated in metastatic breast tumors and its expression is retained in ER-negative tumors. In this study, we examined the mechanism and significance of PELP1 mediated signaling in ER-negative breast cancer progression. We have established ER-negative model cells (MDA-MB231 and 4T1 cells) that stably express PELP1-shRNA. These model cells showed decreased PELP1 expression (75% of endogenous levels) and exhibited decreased propensity to proliferate in in vitro growth assays. Boyden chamber and wound healing assays showed PELP1 down regulation substantially affect migration of ER-negative cells and showed alterations in the expression of the EMT markers. Focused microarray studies identified PELP1 modulate expression of eight genes involved in the EMT (including MMPs, E-cadherin, MTA1). Overexpression of PELP1 in nonmetastatic cells increases their propensity for metastasis in vivo xenograft assays, while, PELP1 knockdown in metastatic model cells decreased in vivo metastatic potential of ER negative breast cancer cells. Whole genome microRNA array analysis revealed that miR 200a and miR141 were upregulated in MDA-MB231 and 4T1 cells expressing PELP1-shRNA compared to control shRNA expressing cells. Over expression of PELP1 in low metastatic model cells decreased expression of miR 200a and miR141. Mechanistic studies showed PELP1 down regulate expression of metastasis suppressive microRNAs (miR 200a and miR141) by promoting chromatin modifications. Ectopic expression of miR 200a and miR141 mimetics decreased PELP1 oncogenic function in ER-negative cells. These results suggest that PELP1 play a role in ER-negative breast cancer metastasis by promoting cell motility / EMT by modulating microRNA expression and blockage of PELP1 axis has potential to reduce metastasis potential of ER-negative breast cancer cells. Understanding how NR coregulator PELP1 plays a role in metastasis will be useful in maximizing treatment opportunities 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 1464. doi:10.1158/1538-7445.AM2011-1464
Abstract 147: Identification of miRNA associated with chemoresponse using combined clinical, population, and cellular data in lung cancer
Authors: Putila Joseph J. , Guo Lan
Published: June 2012

Introduction: MiRNA are potentially important moderators of chemoresponse in human cancer due to their widespread regulatory function. Identification of a set of clinically validated and biologically relevant miRNA could serve as potential markers for prognostication, chemoresponse prediction, and novel therapeutic targets. The objective of this study was to utilize population, clinical, and cell-line data as an integrative approach to identifying miRNA showing a consistent association with chemoresponse.

Materials and Methods: Patients diagnosed with squamous cell carcinomas of the lung between 2004 and 2007 were retrieved from the linked SEER-Medicare database with data on tumor TNM markers, grade, survival, and treatment information (N=6,215). Medicare HCPCS and Revenue codes were used to identify patients receiving cisplatin (N=142), carboplatin (N=1,125), etoposide, (N=37), and paclitaxel (N=779). The AJCC TNM markers and grade were used to partition patients into disjoint groups indicative of tumor progression, with the average survival being calculated for each group. A second set of clinical data containing miRNA expression (N=57, GSE 16025) was partitioned in the same manner, with the average miRNA expression on 328 probes being calculated for each group. Linear regression was used to estimate the association between miRNA expression in the clinical cohort and survival in the population sample given similar tumor characteristics. This analysis was also performed on two subsets of patients receiving surgery and chemotherapy both with and without preoperative radiation. A second analysis utilizing the NCI-60 anti-cancer screen estimated the association between miRNA expression and the amount of each chemotherapeutic agent needed for 50% growth-inhibition in an experimental setting. MiRNA which showed a significant association in at least one of the analyses and concordance in all others were considered for further analysis using IPA software.

Results: Multiple miRNA showed consistent associations with chemoresponse across analytic approaches as well as having documented interactions with molecular species known to play a role in human cancers. Notably, over-expression of miR-25, 27a, 141, and 181a showed a strong association with chemosensitivity in three of the four agents considered and formed an interaction network including transcriptional regulation, HDAC, and EGF activity. Over-expression of miR-133b was associated with chemoresistance in three of four agents. Numerous other miRNA formed networks specific to a single agent.

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 147. doi:10.1158/1538-7445.AM2011-147
Abstract 1470: Depletion of glycosphingolipids with MBO-asGCS eliminates cancer cell metastasis
Authors: Bhinge Kaustubh N. , Gupta Vineet , Liu Yong Y.
Published: June 2012

Tumor metastasis, particularly multi-organ metastasis often causes failure of cancer treatment. It is well-known that the interaction of tumor cells with extracellular matrix (ECM) determines the metastatic ability of cancer cells; however, it is not clear whether depletion of glycosphingolipids (GSLs), a major component of GSL-enriched microdomain on plasma membrane is an approach to eliminate tumor metastasis. Glucosylceramide synthase (GCS) that converts ceramide to glucosylceramide is a limiting enzyme controlling GSL synthesis. We found that overexpression of GCS enhanced metastatic ability of human breast cancer cells. In MCF-7/Dox cells, GCS protein levels were increased 39 folds and GCS activity were increased 2 folds, as compared to MCF-7 cells. The wound healing, Matrigel attachment and MMP-9 activity in MCF-7/Dox cells increased 1.5 folds, 3 folds, and 2 folds respectively compared to MCF-7 cells. Introduction of GCS gene overexpressed GCS protein and significantly increased wound healing and Matrigel attachment by 2 folds and cell invasion 1.5 folds in MCF-7 cells. MBO-asGCS is a mixed backbone oligonucleotide that substantially suppresses GCS expression. Silencing of GCS with MBO-asGCS (100 nM) decreased the wound healing by 2 folds, Matrigel attachment by 1.5 folds and cell invasion by 3 folds in MCF/Dox cells. These results were also observed in MCF-7/DOX cells treated with d-PDMP, a GCS inhibitor. Mechanistic study indicated that overexpression of GCS increased GSLs, particular globo-series GSLs and enhanced VEGF and uPA to promote the mobility, cellular attachment and invasion of cancer cells. As GCS overexpression is tightly associated with drug-resistant cancer cells, this study may suggest that depletion of GSLs with MBO-asGCS is an effective approach to eliminate the metastasis of cancers that even fail in conventional chemotherapy.

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 1470. doi:10.1158/1538-7445.AM2011-1470
Abstract 1474: Semaphorin 3A potentiates metastatic disease by binding to endothelial Neuropilin-1 and disrupting vascular barrier function
Authors: Acevedo Lisette M. , Desgrosellier Jay , Cheresh David A.
Published: June 2012

We previously showed that Semaphorin 3A (Sema3A), a known inhibitor of axonal sprouting, inhibits VEGF-induced angiogenesis yet induces vascular permeability. In patient samples, immunohistochemical analysis of Sema3A showed that its expression increased with disease progression and metastasis. Similarly, Sema3A expression was higher in cell lines with enhanced metastatic potential. We considered whether Sema3A expression in a variety of highly malignant tumor cells might contribute to their metastatic properties based on Sema3A's capacity to disrupt vascular barrier function. To evaluate this, we stably knocked down Sema3A expression in CT26 (colon) and B16-BL6 (skin) cells and examined their growth and invasive properties both in vitro and in vivo. Loss of Sema3A significantly decreased the incidence of pulmonary lung metastasis. Importantly, Sema3A knockdown did not impair tumor cell adhesion, migration, proliferation, or anchorage-independent growth in vitro; and it had no effect on primary tumor growth and angiogenesis in vivo, suggesting a role for Sema3A in tumor cell extravasation. Furthermore, tamoxifen-inducible conditional knockout of the Sema3A receptor Neuropilin-1 (Nrp1) within the adult endothelium inhibited lung colonization and metastasis but had no effect on primary tumor growth. Similarly, a function blocking antibody against Nrp1 known to inhibit Sema3A-mediated permeability prevented lung colonization. Because Nrp1 is also a co-receptor for VEGF, we reintroduced a mutant of Nrp1 that lacks Sema3A but not VEGF binding capability into our tamoxifen-inducible endothelial-specific Nrp1 knockout mouse. Expression of mutant Nrp1 inhibited experimental metastasis, but not primary tumor growth confirming a specific role for Sema3A-Nrp1 interaction in extravasation. Together these findings define a pathological role for tumor cell secreted Sema3A as a potentiator of tumor cell metastasis and vascular barrier disruption.

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 1474. doi:10.1158/1538-7445.AM2011-1474
Abstract 1494: The role of microenvironment in mammary epithelial cell plasticity
Authors: Correia Ana Luisa , Mori Hidetoshi , Schmitt Fernando C. , Bissell Mina J.
Published: June 2012

Understanding breast cancer heterogeneity is crucial for the development of targeted therapeutic interventions. One source of this intratumoral diversity comes from changes induced in epithelial cells by signals they receive from the stromal microenvironment. These changes include the epithelial-to-mesenchymal transition (EMT), a process of cellular plasticity by which epithelial cells disengage cell-cell and cell-extracellular matrix interactions, alter cytoskeletal structure, and implement a transcriptional program that facilitates the acquisition of aggressive traits, such as increased motility, invasiveness and resistance to apoptosis.

Bissell lab has demonstrated that an extracellular protease, matrix metalloproteinase-3 (MMP3), is able to initiate the formation of mammary tumors in mice, as well as trigger EMT in mammary epithelial cells when activated. Furthermore, the observed EMT in MMP3-overexpressing cells was found to be dependent upon reactive oxygen species (ROS) production. However, it is not clear how this extracellular secreted protein functions with an epithelial cell to affect its intracellular events.

To understand the mechanism by which MMP3 drives transformation of mammary cells, we asked which domain of MMP3 is required for ROS production or EMT in mammary epithelial cells, and we are investigating cell surface proteins that may be target of degradation or binding partner of MMP3 during tumorigenesis. This work will unravel new candidates for specific inhibition, providing attractive options for treatment of this and other diseases in which MMP3 plays a pathological role.

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 1494. doi:10.1158/1538-7445.AM2011-1494
Abstract 153: Reduction of microRNAs miR-15a and miR-16-1 in odontogenic keratocyst
Authors: Gomez Ricardo S. , Diniz Marina G. , Gomes Carolina C. , Castro Wagner H. , Guimarães Andre Luiz S. , de Paula Alfredo Maurício B.
Published: June 2012

Odontogenic keratocyst (OKC) is a benign destructive recurrent odontogenic cystic neoplasm. MicroRNAs (miRNAs) miR-15a and miR-16-1 are small non-protein coding RNAs that function as negative regulators of the anti-apoptotic gene BCL-2 at the post-transcriptional level. Increased immunoexpression of BCL-2 protein is reported in OKC. The purpose of the present study was to investigate whether miR-15a and miR-16-1 transcription is altered in OKC and if it is associated with BCL-2 expression in such lesions. Compared to dental follicles, we found higher BCL-2 mRNA expression and immunoreactivity in OKC. Our findings also showed that miR-15a and/or miR-16-1 are downregulated in the majority of OKC samples (24/28). Furthermore, in all five OKC paired samples (primary and marsupialized lesions) investigated there was an increase in the expression of miR-15a after marsupialization. Our results suggest that OKC neoplastic cells present an anti-apoptotic profile to which lower miR-16-15a expression might contribute. Additionally, our findings strongly suggest that marsupialization reduces BCL-2 expression in the OKC and this downregulation may result from microRNA post-transcriptional activity, even though this cause-effect relationship remains to be proved.

This study was supported by FAPEMIG and CAPES, Brazil.

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 153. doi:10.1158/1538-7445.AM2011-153
Abstract 1534: Laminin binding integrin functions in human bone metastatic cancer
Authors: Sroka Isis C. , Gard Jaime M.C. , Pond Erika , Pawar Sangita C. , Nagle Raymond B. , Cress Anne E.
Published: June 2012

Laminin binding integrins are major determinants of cancer cell migration, invasion and metastasis. In human prostate cancer, both A6B1 and A3B1 laminin-binding integrins are expressed on tumor cell surfaces as observed in either prostatectomy or needle biopsy specimens. In human breast cancer, the A6 integrin is expressed in both primary tumors and in metastatic lesions. Integrin A6B1 is post-translationally modified on the tumor cell surface by urokinase-type plasminogen activator (uPA), producing a structural variant, A6pB1. While the A6pB1 form is devoid of the ligand binding domain, A3B1 is fully functional and not subject to cleavage. In this study, we observed the continued expression of the A6B1 integrin on tumor cell surfaces within human bone metastatic lesions as well as in human tumor xenografts growing within bone. The cleavage function of the A6 integrin was found to be constitutively expressed on nine different cancer cell lines derived from breast, prostate, lung, pancreatic tumors. Interestingly, five different normal cell types expressing the adhesion active A6B1 integrin did not have the constitutive cleavage function. However, the cleavage function in normal cells was inducible by the exogenous addition of uPA. Selection of successive bone resident cancer cells selects for constitutive cleavage of A6 integrin and increasing expression of A3B1 integrin. Taken together, these data suggest that the cleavage function is constitutively activated in cancer specimens and opens the possibility cleavage mediated release from laminin binding may be coordinated with A3 dependent adhesion. (Supported in part by CA23752 and the TACMASS core service of the Arizona Cancer Center).

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 1534. doi:10.1158/1538-7445.AM2011-1534
Abstract 1540: Targeting PI3K/mTOR inhibitor induced survival programs abrogates resistance to cell death in ECM-attached cancer cells
Authors: Muranen Taru E. , Morales Fabiana , Selfors Laura , Worster Devin , Albeck John , Gao Sizhen , Iwanicki Marcin , Mills Gordon , Brugge Joan S.
Published: June 2012

Alterations in the PI3-kinase pathway are common in breast, endometrial, and ovarian cancer and are thought to serve as major drivers of proliferation and survival. Multiple compounds targeting PI3-kinase pathway are currently in clinical trials.

We have examined the sensitivity of ovarian and breast tumor cell lines to dual PI3K/mTOR inhibitors in 3D tumor spheroid assays. Interestingly, tumor cells in the center of the spheroids that are not attached to matrix are generally highly sensitive to NVP-BEZ235 and undergo apoptosis, whereas those in contact with matrix are highly resistant. In order to understand the basis for the differential sensitivity to NVP-BEZ235 and to identify candidate targets to abrogate this resistance, we performed reverse phase protein array of tumor spheroids treated with NVP-BEZ235. While NVP-BEZ235 inhibited known downstream targets of PI3K/mTOR, there was significant up-regulation of multiple proteins known to regulate cell survival including IGF1R, p-EGFR and several Bcl-2 family members. This response raised the question whether combined inhibition of PI3K/mTOR and any of the induced proteins would sensitize the matrix-attached cells. Interestingly, inhibition of Bcl-2 by ABT737 caused widespread apoptosis in the 3D structures, but only in combination with NVP-BEZ235. In addition, matrix-resistance was abrogated by combined treatment with NVP-BEZ235 and inhibition of EGFR or knockdown IGF1R.

These results indicate that inhibition of PI3K/mTOR leads to induction of several protective pathways and that suppression of these pathways can significantly enhance sensitivity to PI3K/mTOR targeted therapies. In addition, these studies suggest a rational approach to the development of combination therapies – that is, through identification of drug-induced survival pathways and targeting these pathways in combination. Our current efforts center on investigating the mechanisms of PI3K/mTOR inhibition resistance and addressing the efficacy of the dual treatment in preclinical models.

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 1540. doi:10.1158/1538-7445.AM2011-1540
Abstract 1556: Adipose tissue upregulates MMP9 expression in oesophageal cancer promoting invasion and migration in vitro and correlates with obesity status and poor differentiation in vivo
Authors: Pidgeon Graham Philip , Allott Emma , Donohoe Claire , Cathcart MaryClare , McGarrigle Sarah , Cummins Robert , Kay Elaine , Reynolds John
Published: June 2012

Introduction: Obesity is an independent risk-factor for oesophageal adenocarcinoma. Adipose tissue is an endocrine organ secreting numerous factors with different biological activities. We aimed to investigate the molecular mechanisms linking obesity and cancer in oesophageal cancer.

Methods: Adipose conditioned media (ACM) was prepared from omental adipose tissue of oesophageal adenocarcinoma patients. Proliferation of oesophageal adenocarcinoma cells(OE33, OE19) in response to ACM was examined by BrdU. OE33 cell line was co-culture with visceral adipose tissue and gene expression pathways assessed by Cancer-Pathway-Finder and Affymetrix arrays. Identified genes were assessed in 50 resected oesophageal tumours and related to clinic-pathological data. Migration and invasion following culture with ACM was assessed in oesophageal cell lines.

Results: Culture of both the OE33 and OE19 cell lines with ACM from omental adipose tissue increased proliferation by 142% and 145% respectively. Co-culture of OE33 with adipose tissue increased the expression of genes regulating invasion and metastasis between 10-5000 fold, with MMP9 the most upregulated gene and TP53 down-regulated 2-fold. Altered genes were validated in an independent cohort. Functionally, co-culture of adipose tissue with tumour cells increased both mingration and invasion of tumour cells. Notably, adipose tissue from viscerally obese patients had a significantly higher effect. Markers of focal adhesions(SPP1, integrins), endothelial mesenchymal transition(SNAI2, Laminins) and thrombosis (pai-1) were also significantly upregulated. Expression of pai-1 and MMP9 was significantly (p<0.05) higher in tumours from centrally obese patients.

Conclusion: Omental adipose tissue promoted oesophageal cancer aggressiveness by increasing proliferative, migratory and invasive capacity via upregulation of MMP2, MMP9, SERPINE1, PAI-1, SPP1 and SNAI2. Upregulation of genes in tumours from obese patients suggest a molecular progression of cancer associated with excess adipose tissue.

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 1556. doi:10.1158/1538-7445.AM2011-1556
Abstract 1572: Characterising the tumor vasculature in vivo in mouse models of colorectal cancer using contrast enhanced high-frequency ultrasound
Authors: Marston Gemma , Jones Pam F. , Evans John A. , Hull Mark A. , Markham Alex F. , Coletta Patricia L.
Published: June 2012

Angiogenesis is essential for tumours to grow beyond a few millimetres in size and to metastasise, making it an attractive target for both cancer imaging and therapeutic intervention. Although microvessel density (MVD) is routinely used to assess tumour vascularity in fixed tissue, few techniques are currently available for imaging and quantitating tumour vasculature parameters in vivo.

High-frequency ultrasound (HFUS) allows high resolution, non-invasive longitudinal imaging of tumours in vivo. Incorporation of microbubble contrast agent into imaging protocols allows visualisation of the vasculature, determination of relative blood flow and perfusion, and the ability to directly target and quantify molecular biomarkers of disease in vivo.

We have been investigating in vivo tumour blood flow and vascularity in the growth of human colorectal cancer (CRC) cell xenografts. CD1 Nu/Nu mice implanted with SW480 cell xenografts were used to investigate the relationship between tumour growth and different vascular parameters obtained by contrast enhanced (CE) HFUS. Mice were imaged at day 21 and day 27 of tumour growth using the VisualSonics Vevo 770 system. A single bolus of microbubbles was injected via a syringe driver into the tail vein during 2D CE HFUS imaging, with the wash-in data loops captured prior to 3D CE HFUS imaging, and tissue samples collected for histology and immunohistochemistry. Time intensity curves were generated post-acquisition and used to determine perfusion kinetics and vascular data. A number of strongly significant correlations were observed relating in vivo and histological tumour characteristics with relative blood flow and total vascularity. These included the size of the tumour, tumour growth and the total vascular space.

This study shows that CE HFUS is a powerful qualitative and quantitative tool for the analysis of tumour angiogenesis in vivo. It provides a relatively non-invasive method to monitor tumour blood flow and vascularity in longitudinal studies thus allowing effects on angiogenesis due to therapeutic intervention to be monitored. We are currently developing this technique for use with autochthonous colorectal cancer models.

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 1572. doi:10.1158/1538-7445.AM2011-1572
Abstract 1611: Hepatocellular carcinoma xenograft models and biomarkers are powerful tools for the evaluation of the new drugs targeting HCC
Authors: Sun Yanmei , Zhang Juan , Li Nan , Song Xiaoming , Cai Jie , Chen Taiping , Wery Jean-Pierre , Chen Yiyou
Published: June 2012

Hepatocellular Carcinoma (HCC) is a major health problem, as the fifth most common cancer and the third most common cause of cancer death worldwide. Many pharmaceutical companies lead the effort to design new medicines on this cancer type. The overwhelming need to improve preclinical models of HCC requires robust models that closely mimic the disease population and therefore have the potential to better predict clinical outcome with novel therapies. Here we successfully validated subcutaneous and orthotopic xenograft models derived from HepG2, SK-HEP-1, Hep3B, PLC/PRF/5, HUH-1, HUH-7 and MHCC97H cell lines and also directly from HCC patient tumors (HuPrime®). Four HCC serum markers (AFP, α-fetoprotein; AFP-L3; DCP, Des-gamma-Carboxyprothrombin; GP73, Golgi Protein-73) have been used or will be potentially used clinically in detection of this disease. AFP is the most widely used biomarker in HCC, somehow it is not always correlated well with the liver cancer progress, even it gives false result, and some liver lesion or liver cirrhosis can also produce high level of AFP; while GP73 is reported a promising alternative as HCC serum marker. AFP and GP73 were tested at both mRNA level and protein level. They were also compared in the sensitivity and correlation with the tumor burden using the blood samples from the orthotopic xenograft models. Our results demonstrated that biomarkers released by the tumor models could well monitor the tumor take rate, growth and response to treatments. Furthermore, Sorafenib, one popular anti- HCC medicine, was tested, and the serum biomarkers could be utilized for confidence in evaluating the efficacy of Sorafenib. In conclusion, the use of HCC xenograft models combined with the biomarker strategies is helpful in maximizing the value of in vivo research and designing 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 1611. doi:10.1158/1538-7445.AM2011-1611
Abstract 1625: Role of EphB4 in esophageal cancer: Expression, amplification, and therapeutic inhibition
Authors: Hasina Rifat , Kanade Geetanjali , Yala Soheil , Mollberg Nathan , Muller Jeffery , Surati Mosmi , Kanteti Rajani , Husain Aliya , Posner Mitchell , Waxman Irvine , Vigneswaran Wickii , Ferguson Mark , Villaflor Victoria , Vokes Everette E. , Gill Parkash , Salgia Ravi
Published: June 2012

EphB4 is a member of the largest family of receptor tyrosine kinases (RTKs), classically associated with neural development and vascular patterning in embryonic life. The cellular responses to Eph receptor stimulation by their ephrin ligands are important in mediating a wide range of biological activities, including angiogenesis, cell segregation, cell attachment, shape, and motility. EphB4 has been showed to play an oncogenic role in a number of tumors, and we report the first investigation into its role in esophageal cancer, a disease whose survival has not improved and would benefit from the identification of new targets in its treatment. We have addressed this need by exploring the Eph/ephrin receptor tyrosine kinase pathway. We utilized tissues archived at the University of Chicago as well as commercially purchased TMAs to evaluate the expression of EphB4 by IHC. Approximately 93 squamous cell carcinoma, 100 adenocarcinoma and 25 adjacent normal control samples were utilized. In addition, four adenocarcinoma and nine squamous cell carcinma cell lines were used for in vitro studies. Statistical analysis of IHC data showed a consistently higher expression of EphB4 in both squamous and adenocarcinoma compared to adjacent normal tissue. A statistically significant correlation was established between EphB4 expression and higher grades of squamous cell carcinoma, suggesting that overexpression of EphB4 in squamous cell carcinoma is directly linked to clinically aggressive tumors. The EphB4 gene was found amplified in 8/16 squamous cell carcinoma (30% with a gene copy number ≥ 3, 30% with >8 copies and 10% with a copy number of 20. Of the adenocarcinomas, 3/7 samples were amplified (43% with a gene copy number of ≥4, and 14% >8 copies). Three of 9 squamous cell carcinoma cell lines had a gene copy number ≥4 and rest of them had no significant variation. Only one of four adenocarcinoma cell lines had an increased gene copy number. In vitro experiments with EphB4 specific siRNA inhibited the motility and proliferation of cultured cells and the inhibition of EphB4 specifically abrogated the phosphorylation of functional proteins associated with cell motility and proliferation, especially that of phospho-FAK and phospo-AKT, the expression of which were abrogated completely by the inhibition of EphB4. Our data imply that EphB4 plays a crucial role in esophageal cancer and should be further evaluated as a therapeutic target in this disease.

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 1625. doi:10.1158/1538-7445.AM2011-1625
Abstract 1713: Mechanisms of resistance to platinum based drugs uncovered by protection caused by substituted coumarins
Authors: Nolan Karen A. , Scott Katherine A. , Griffiths Gareth , Stratford Ian J.
Published: June 2012

Disruption of p53 can have a profound effect on cellular sensitivity to Platinum-based drugs. Inhibition of NQO1 by dicoumarol and other substituted coumarins can target p53 for degradation. Thus, we tested the ability of NQO1 inhibitors to protect HCT116 cells (containing wild type p53) against the cytotoxic effects of cisplatin. All the NQO1 inhibitors protect cells against the damaging effects of cisplatin (see the table for representative data for one of the inhibitors, AS3). Protection was also seen in a second cell line with wild type p53 (RT112 bladder carcinoma cells). To confirm p53 dependence, experiments were carried out using cells with mutant (MDA231) or null (HCT116 -/-) p53. Surprisingly, the coumarin-based agents also protected these cells against cisplatin-induced damage. In addition, these observations were not dependent on NQO1, since MDA231 cells, with negligible NQO1, and cells overexpressing NQO1 (MDA321-DTD) were similarly protected. Protection is also observed for oxaliplatin but, interestingly, there is no protection against etoposide toxicity.

Cell cycle analysis of HCT116 cells treated with cisplatin show that, 24 hours after treatment, cells are blocked in G2. When cells are given the dicoumarol analogues at the same time as the cisplatin, no cell cycle delay is observed. Further, analysis of apoptosis mediators shows that treatment with AS3 inhibits oxaliplatin induction of Bak and reduces caspase-3 activity. Understanding the mechanism by which treatment with the dicoumarol analogues can cause resistance to cisplatin could reveal new methods for potentially overcoming resistance to platinum-based drugs in the clinic.

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 1713. doi:10.1158/1538-7445.AM2011-1713
Abstract 220: BRCA1 regulates p53 target expression via DNp73
Authors: Scata Kimberly A. , El-Deiry Wafik S.
Published: June 2012

In response to cellular stresses, the tumor suppressor gene p53 is stabilized and transactivates several categories of target genes, including cell cycle arrest genes and pro-apoptotic genes. These sets of genes are not activated simultaneously and how the differential expression of these targets occurs has been the subject of intense scrutiny. We have previously shown that overexpression of BRCA1 stabilizes p53 but fails to activate the expression of its proapoptotic targets. When BRCA1 is overexpressed, the posttranslational modifications of p53 are the same as those that occur in response to stress and p53 is still able to bind to the promoters of the proapoptotic targets. In order to determine how BRCA1 regulates p53 gene expression, we've explored the role of the p53 family members. We find that BRCA1 is able to induce DNp73, a dominant negative acting isoform of p73. Unexpectedly, we found that BRCA1 upregulates DNp73 expression, an isoform of the p53 family member p73 lacking the transactivation domain, which has been previously implicated in cell survival. This observation has important implications for understanding the selectivity of p53-dependent transcription as well as the tumor suppressive action of BRCA1 that favors DNA repair over cell death.

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 220. doi:10.1158/1538-7445.AM2011-220