Medicine and Health Sciences Commons^™

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria, Donna Santillan, Mark Santillan, Stephen Hunter

Stephen K. Hunter

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

A Common Human Beta Globin Splicing Mutation Modeled In Mice., J. Lewis, Baoli Yang, R. Kim, H. Sierakowska, R. Kole, O. Smithies, N. Maeda

Baoli Yang

The betaIVS-2-654 C-->T mutation accounts for approximately 20% of beta thalassemia mutations in southern China; it causes aberrant RNA splicing and leads to beta0 thalassemia. To provide an animal model for testing therapies for correcting splicing defects, we have used the "plug and socket" method of gene targeting in murine embryonic stem cells to replace the two (cis) murine adult beta globin genes with a single copy of the human betaIVS-2-654 gene. No homozygous mice survive postnatally. Heterozygous mice carrying this mutant gene produce reduced amounts of the mouse beta globin chains and no human beta globin, and have …

Identification Of A Tripartite Basal Promoter Which Regulates Human Terminal Deoxynucleotidyl Transferase Gene Expression., D. Bhaumik, Baoli Yang, T. Trangas, J. Bartlett, M. Coleman, D. Sorscher

Baoli Yang

In order to locate the promoter region of the human terminal deoxynucleotidyl transferase gene, serially truncated segments of the 5'-flanking region of the gene were cloned into a chloramphenicol acetyltransferase reporter vector. Transient transfection analyses of the terminal transferase-reporter gene constructs identified the basal promoter region within -34 to +40 base pairs relative to the transcription start site. Three promoter elements were defined in this region. The primary element is within 34 base pairs upstream of the transcription start site. The CAP site is 62 base pairs upstream of the translation start site. The secondary element involves sequences around the …

Loss Of Mll Phd Finger 3 Is Necessary For Mll-Enl-Induced Hematopoietic Stem Cell Immortalization, J. Chen, Donna Santillan, M. Koonce, W. Wei, R. Luo, M. Thirman, N. Zeleznik-Le, M. Diaz

Donna A. Santillan

Reciprocal chromosomal translocations at the MLL gene locus result in expression of novel fusion proteins, such as MLL-ENL, associated with leukemia. The three PHD finger cassette, one of the highly conserved domains in MLL, is absent in all fusion proteins. This domain has been shown to interact with Cyp33, a cyclophilin which enhances the recruitment of histone deacetylases (HDAC) to the MLL repression domain and mediates HOX gene repression. Insertion of the third PHD finger of MLL into MLL-ENL allows the recruitment of Cyp33 and, subsequently, HDAC1 to the fusion protein. Furthermore, expression of the fusion protein with the PHD …

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria, Donna Santillan, Mark Santillan, Stephen Hunter

Donna A. Santillan

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria, Donna Santillan, Mark Santillan, Stephen Hunter

Mark K. Santillan

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

Intrinsic Differences In The Response Of The Human Lutropin Receptor Versus The Human Follitropin Receptor To Activating Mutations, Meilin Zhang, Ya-Xiong Tao, Ginny Ryan, Xiuyan Feng, Francesca Fanelli, Deborah Segaloff

Ginny L. Ryan

In contrast to the human lutropin receptor (hLHR), very few naturally occurring activating mutations of the structurally related human follitropin receptor (hFSHR) have been identified. The present study was undertaken to determine if one aspect underlying this discrepancy might be a general resistance of the hFSHR to mutation-induced constitutive activity. Five different mutations were introduced into both the hLHR and hFSHR (four based on activating mutations of the hLHR gene, one based on an activating mutation of the hFSHR gene). Our results demonstrate that hFSHR constitutively activating mutants (CAMs) were not as active as hLHR CAMs containing the comparable mutation. …

Evaluating The Roles Of Follicle-Stimulating Hormone Receptor Polymorphisms In Gonadal Hyperstimulation Associated With Severe Juvenile Primary Hypothyroidism, Ginny Ryan, X. Feng, C. D'Alva, M. Zhang, Bradley Van Voorhis, E. Pinto, A. Kubias, S. Antonini, A. Latronico, D. Segaloff

Ginny L. Ryan

CONTEXT: Rare activating mutations of the human (h)FSHR have been reported in some women with spontaneous ovarian hyperstimulation in pregnancy, where follicular growth is inappropriately stimulated by elevated concentrations of human chorionic gonadotropin acting through the hFSHR. It is not known whether ovarian hyperstimulation in peripubertal girls with untreated primary hypothyroidism is caused by hFSHR mutations and/or influenced by hFSHR allelic variants, rendering the hFSHR more sensitive to circulating TSH. OBJECTIVE: The aim of the study was to determine whether mutations of the hFSHR and/or hFSHR allelic variants are associated with greater sensitivity of the hFSHR to TSH. DESIGN: The …

A Mechanism For Synergy With Combined Mtor And Pi3 Kinase Inhibitors, S. Yang, X. Xiao, Xiangbing Meng, Kimberly Leslie

Xiangbing Meng

Dysregulation of the mammalian target of rapamycin (mTOR) signaling has been found in many human cancers, particularly those with loss of the tumor suppressor PTEN. However, mTORC1 inhibitors such as temsirolimus have only modest activity when used alone and may induce acquired resistance by activating upstream mTORC2 and Akt. Other tumors that do not depend upon PI3K/Akt/mTOR signaling for survival are primarily resistant. This study tested the hypothesis that the limited clinical efficacy of temsirolimus is due to a compensatory increase in survival signaling pathways downstream of Akt as well as an incomplete block of 4E-BP1-controlled proliferative processes downstream of …

Amifostine Enhancement Of The Anti-Cancer Effects Of Paclitaxel In Endometrial Cancer Is Tp53-Dependent, W. Luo, F. Wu, R. Elmaoued, B. Beck, E. Fischer, Xiangbing Meng, Kimberly Leslie, Donghai Dai

Xiangbing Meng

Endometrial cancer (ECa) is the fourth most common malignancy in women. Currently, there is no effective therapy for advanced and recurrent cancer. Among the poor-outcome endometrial cancers, there is a high frequency of TP53 mutations. We have previously reported that amifostine has a direct anti-cancer effect and has a significant synergistic effect with paclitaxel when used in endometrial cancer cell and xenograft models. In this report, using a cell line with knock-down p53 expression through siRNA, we found that amifostine enhancement of paclitaxel's anticancer effect is p53 status-dependent. Amifostine promotes entry into the G2-M phase through regulation of cyclin-dependent kinase-1 …

Cytoplasmic Metadherin (Mtdh) Provides Survival Advantage Under Conditions Of Stress By Acting As Rna-Binding Protein, Xiangbing Meng, Danlin Zhu, Shujie Yang, Xinjun Wang, Zhi Xiong, Yuping Zhang, Pavla Brachova, Kimberly Leslie

Xiangbing Meng

Overexpression of metadherin (MTDH) has been documented in many solid tumors and is implicated in metastasis and chemoresistance. MTDH has been detected at the plasma membrane as well as in the cytoplasm and nucleus, and the function of MTDH in these locales remains under investigation. In the nucleus, MTDH acts as a transcription co-factor to induce expression of chemoresistance-associated genes. However, MTDH is predominantly cytoplasmic in prostate tumors, and this localization correlates with poor prognosis. Herein, we used endometrial cancer cells as a model system to define a new role for MTDH in the cytoplasm. First, MTDH was primarily localized …

Cell Encapsulation As A Potential Nondietary Therapy For Maternal Phenylketonuria., Donna Santillan, Mark Santillan, Stephen Hunter

Stephen K. Hunter

OBJECTIVE: The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria.

STUDY DESIGN: Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry.

RESULTS: Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly …

Effects Of Bevacizumab In Mouse Model Of Endometrial Cancer: Defining The Molecular Basis For Resistance, S. Davies, Donghai Dai, G. Pickett, K. Thiel, V. Korovkina, Kimberly Leslie

Donghai Dai

Endometrial cancer is the most frequent gynecologic cancer in women. Long-term outcomes for patients with advanced stage or recurrent disease are poor. Targeted molecular therapy against the vascular endothelial growth factor (VEGF) and its receptors constitute a new therapeutic option for these patients. The goal of our study was to assess the potential effectiveness of inhibition of VEGF/VEGFR signaling in a xenograft model of endometrial cancer using bevacizumab (Avastin, a humanized antibody against VEGFA). We also aimed to identify molecular markers of sensitivity or resistance to this agent. We show that bevacizumab retards tumor growth in athymic mice by inhibiting …

A Potential Synergistic Anticancer Effect Of Paclitaxel And Amifostine On Endometrial Cancer, Donghai Dai, A. Holmes, T. Nguyen, S. Davies, D. Theele, C. Verschraegen, Kimberly Leslie

Donghai Dai

Although paclitaxel is one of the most effective chemotherapeutic agents, its usefulness is still limited in advanced and recurrent endometrial cancer. Amifostine protection of normal tissues against the side effects of chemotherapeutic agents has been clinically proven in cancer patients; however, its application in endometrial cancer has not been fully evaluated. We have investigated the use of paclitaxel and amifostine in controlling the growth of poorly differentiated endometrial cancer cells, Hec50co, in vitro and in vivo. Our studies show that amifostine had direct anticancer effects on endometrial cancer cells in vitro by arresting the cell cycle at the G1 phase …

Amifostine Enhancement Of The Anti-Cancer Effects Of Paclitaxel In Endometrial Cancer Is Tp53-Dependent, W. Luo, F. Wu, R. Elmaoued, B. Beck, E. Fischer, Xiangbing Meng, Kimberly Leslie, Donghai Dai

Donghai Dai

Endometrial cancer (ECa) is the fourth most common malignancy in women. Currently, there is no effective therapy for advanced and recurrent cancer. Among the poor-outcome endometrial cancers, there is a high frequency of TP53 mutations. We have previously reported that amifostine has a direct anti-cancer effect and has a significant synergistic effect with paclitaxel when used in endometrial cancer cell and xenograft models. In this report, using a cell line with knock-down p53 expression through siRNA, we found that amifostine enhancement of paclitaxel's anticancer effect is p53 status-dependent. Amifostine promotes entry into the G2-M phase through regulation of cyclin-dependent kinase-1 …

Progesterone Receptor Isoform Identification And Subcellular Localization In Endometrial Cancer, Kimberly Leslie, M. Stein, N. Kumar, Donghai Dai, J. Stephens, A. Wandinger-Ness, D. Glueck

Donghai Dai

OBJECTIVE: These studies were undertaken to characterize the subcellular localization of the two major isoforms of progesterone receptors (PR), PRA and PRB, in endometrial cancer. METHODS: Immunohistochemistry, immunoprecipitation, and confocal microscopy were performed using Hec50co and KLE endometrial cancer cell models expressing PRA or PRB as a consequence of transduction. The location of PRB compared to PRA was determined, and antibodies were tested for specificity with respect to PR isoform recognition. Immunohistochemical analyses of PR expression and subcellular compartmentalization were also performed on 20 formalin-fixed endometrial cancer tumors. RESULTS: Morphological and biochemical evaluations demonstrated that PRA is localized to the …

Identification Of A Novel Mechanism Of Nf-Kappab Inactivation By Progesterone Through Progesterone Receptors In Hec50co Poorly Differentiated Endometrial Cancer Cells: Induction Of A20 And Abin-2, S. Davies, Donghai Dai, I. Feldman, G. Pickett, Kimberly Leslie

Donghai Dai

OBJECTIVE: Nuclear factor kappa B (NFkappaB) is a strong anti-apoptotic factor, which is constitutively active in human endometrial cancer cells. Progesterone is the principal growth inhibitory hormone in the endometrial epithelium and promotes apoptosis. To identify the pathways through which progesterone controls NFkappaB function, we explored its genomic and non-genomic effects in endometrial cancer cells. METHODS: PR-negative Hec50co endometrial cancer cells were engineered to express high levels of the A or B isoform of PR (PRA or PRB) by adenoviral infection. Cells were treated with progesterone or vehicle alone, and RNA was isolated. Affymetrix microarrays were performed and transcriptional control …

Preclinical Development Of A Neutral, Estrogen Receptor-Targeted, Tridentate 99mtc(I)-Estradiol-Pyridin-2-Yl Hydrazine Derivative For Imaging Of Breast And Endometrial Cancers, T. Nayak, H. Hathaway, C. Ramesh, J. Arterburn, Donghai Dai, L. Sklar, J. Norenberg, E. Prossnitz

Donghai Dai

Breast and endometrial cancers are the most common invasive malignancies in women, with more than 217,000 new diagnoses per year in the United States. These cancers are often classified into 2 subtypes based on the expression of the classical estrogen receptor. In this study, we describe a new structural class of neutral tridentate 99mTc(I)-estradiol-pyridin-2-yl hydrazine derivatives for potential use in breast and endometrial cancer imaging. METHODS: The 99mTc(I)-estradiol-pyridin-2-yl hydrazine derivative was synthesized via the Sonogashira cross-coupling reaction and radiolabeled via the tricarbonyl approach. Radiochemical purity was assessed by high-performance liquid chromatography. Cell-binding studies were performed with human breast adenocarcinoma MCF-7 …

Relative Contribution Of Nedd4 And Nedd4-2 To Enac Regulation In Epithelia Determined By Rna Interference., Peter Snyder, Jennifer Steines, Diane Olson

Jennifer C. Steines Wagemester

Epithelial Na+ transport is regulated in large part by mechanisms that control expression of the epithelial Na+ channel (ENaC) at the cell surface. Nedd4 and Nedd4-2 are candidates to control ENaC surface expression, but it is not known which of these proteins contributes to ENaC regulation in epithelia. To address this question, we used RNA interference to selectively reduce expression of Nedd4 or Nedd4-2. We found that endogenous Nedd4-2, but not Nedd4, negatively regulates ENaC in two epithelial cell lines (Fischer rat thyroid and H441); small interfering RNA (siRNA) against Nedd4-2 increased amiloride-sensitive Na+ current (compared with control siRNA), but …

Estrogen Receptors Are Present In Human Granulosa Cells., B. Hurst, M. Zilberstein, J. Chou, B. Litman, J. Stephens, Kimberly Leslie

Kimberly K. Leslie

Recent studies failed to detect estrogen receptors in primate follicles. This study was initiated to determine whether estrogen receptor (ER) messenger ribonucleic acid (mRNA) is present in human granulosa cells and, further, if functional ER proteins are present. To evaluate the presence of ER, RNA from human granulosa cells obtained at the time of oocyte retrieval for assisted reproduction was extracted, and complementary DNA synthesis was performed by the reverse transcriptase-polymerase chain reaction. Oligonucleotide primers were used to amplify basepairs 570-852 in the B- and C- domains of the ER mRNA. Southern blotting was performed and confirmed that the amplified …

Effects Of Bevacizumab In Mouse Model Of Endometrial Cancer: Defining The Molecular Basis For Resistance, S. Davies, Donghai Dai, G. Pickett, K. Thiel, V. Korovkina, Kimberly Leslie

Kimberly K. Leslie

Endometrial cancer is the most frequent gynecologic cancer in women. Long-term outcomes for patients with advanced stage or recurrent disease are poor. Targeted molecular therapy against the vascular endothelial growth factor (VEGF) and its receptors constitute a new therapeutic option for these patients. The goal of our study was to assess the potential effectiveness of inhibition of VEGF/VEGFR signaling in a xenograft model of endometrial cancer using bevacizumab (Avastin, a humanized antibody against VEGFA). We also aimed to identify molecular markers of sensitivity or resistance to this agent. We show that bevacizumab retards tumor growth in athymic mice by inhibiting …

Cytoplasmic Metadherin (Mtdh) Provides Survival Advantage Under Conditions Of Stress By Acting As Rna-Binding Protein, Xiangbing Meng, Danlin Zhu, Shujie Yang, Xinjun Wang, Zhi Xiong, Yuping Zhang, Pavla Brachova, Kimberly Leslie

Kimberly K. Leslie

Overexpression of metadherin (MTDH) has been documented in many solid tumors and is implicated in metastasis and chemoresistance. MTDH has been detected at the plasma membrane as well as in the cytoplasm and nucleus, and the function of MTDH in these locales remains under investigation. In the nucleus, MTDH acts as a transcription co-factor to induce expression of chemoresistance-associated genes. However, MTDH is predominantly cytoplasmic in prostate tumors, and this localization correlates with poor prognosis. Herein, we used endometrial cancer cells as a model system to define a new role for MTDH in the cytoplasm. First, MTDH was primarily localized …

Progesterone Regulation Of Activating Protein-1 Transcriptional Activity: A Possible Mechanism Of Progesterone Inhibition Of Endometrial Cancer Cell Growth, Donghai Dai, E. Litman, E. Schonteich, Kimberly Leslie

Kimberly K. Leslie

The uterine endometrium and cancers derived from it are classic models of hormone action: estrogen promotes growth and progesterone inhibits proliferation and results in differentiation. We have now identified a major pathway through which progesterone causes these growth-limiting effects. Ligand-bound progesterone receptors modulate the composition and transcriptional activity of members of the activating protein-1 (AP-1) family, and in particular, c-Jun. First, a dominant negative form of c-Jun inhibits the constitutive growth of Hec50co cells in a manner similar to the effects of progesterone through progesterone B receptors. Second, progesterone inhibits the transcriptional activity of the AP-1 complex in reporter gene …

A Potential Synergistic Anticancer Effect Of Paclitaxel And Amifostine On Endometrial Cancer, Donghai Dai, A. Holmes, T. Nguyen, S. Davies, D. Theele, C. Verschraegen, Kimberly Leslie

Kimberly K. Leslie

Although paclitaxel is one of the most effective chemotherapeutic agents, its usefulness is still limited in advanced and recurrent endometrial cancer. Amifostine protection of normal tissues against the side effects of chemotherapeutic agents has been clinically proven in cancer patients; however, its application in endometrial cancer has not been fully evaluated. We have investigated the use of paclitaxel and amifostine in controlling the growth of poorly differentiated endometrial cancer cells, Hec50co, in vitro and in vivo. Our studies show that amifostine had direct anticancer effects on endometrial cancer cells in vitro by arresting the cell cycle at the G1 phase …

Identification Of A Novel Mechanism Of Nf-Kappab Inactivation By Progesterone Through Progesterone Receptors In Hec50co Poorly Differentiated Endometrial Cancer Cells: Induction Of A20 And Abin-2, S. Davies, Donghai Dai, I. Feldman, G. Pickett, Kimberly Leslie

Kimberly K. Leslie

OBJECTIVE: Nuclear factor kappa B (NFkappaB) is a strong anti-apoptotic factor, which is constitutively active in human endometrial cancer cells. Progesterone is the principal growth inhibitory hormone in the endometrial epithelium and promotes apoptosis. To identify the pathways through which progesterone controls NFkappaB function, we explored its genomic and non-genomic effects in endometrial cancer cells. METHODS: PR-negative Hec50co endometrial cancer cells were engineered to express high levels of the A or B isoform of PR (PRA or PRB) by adenoviral infection. Cells were treated with progesterone or vehicle alone, and RNA was isolated. Affymetrix microarrays were performed and transcriptional control …

Egfr Isoforms And Gene Regulation In Human Endometrial Cancer Cells, L. Albitar, G. Pickett, M. Morgan, J. Wilken, N. Maihle, Kimberly Leslie

Kimberly K. Leslie

BACKGROUND: Epidermal growth factor (EGF) and its receptor (EGFR) constitute a principal growth-promoting pathway in endometrial cancer cells. Pre-clinical studies were undertaken to compare the expression of EGFR isoforms and the downstream effects of activating or blocking EGFR function in Ishikawa H cells, derived from a moderately differentiated type I endometrioid adenocarcinoma, or in Hec50co cells, derived from a poorly differentiated type II adenocarcinoma with papillary serous sub-differentiation. RESULTS: We investigated whether EGFR mutations are present in the tyrosine kinase domain (exons 18-22) of EGFR and also whether EGFR isoforms are expressed in the Ishikawa H or Hec50co cell lines. …

Models Representing Type I And Type Ii Human Endometrial Cancers: Ishikawa H And Hec50co Cells, L. Albitar, G. Pickett, M. Morgan, S. Davies, Kimberly Leslie

Kimberly K. Leslie

OBJECTIVE: Endometrial cancer models are critical to the advancement of investigation, and Ishikawa H and Hec50co cells have been used as research tools. The purpose of these studies is to verify the degree to which these commonly used cell models share the molecular characteristics of the two major in vivo endometrial cancer subtypes, I and II. METHODS: The studies reported include an analysis of pathologic features, tumor suppressor mutations, detailed karyotyping, and cell cycle regulation. RESULTS: Ishikawa H cells are hormone responsive and have lost PTEN expression. In addition they have lost RB1 expression due to a deletion in exon …

Knockdown Of Mtdh Sensitizes Endometrial Cancer Cells To Cell Death Induction By Death Receptor Ligand Trail And Hdac Inhibitor Lbh589 Co-Treatment, Xiangbing Meng, Pavla Brachova, Shujie Yang, Zhi Xiong, Yuping Zhang, Khristina Thiel, Kimberly Leslie

Kimberly K. Leslie

Understanding the molecular underpinnings of chemoresistance is vital to design therapies to restore chemosensitivity. In particular, metadherin (MTDH) has been demonstrated to have a critical role in chemoresistance. Over-expression of MTDH correlates with poor clinical outcome in breast cancer, neuroblastoma, hepatocellular carcinoma and prostate cancer. MTDH is also highly expressed in advanced endometrial cancers, a disease for which new therapies are urgently needed. In this present study, we focused on the therapeutic benefit of MTDH depletion in endometrial cancer cells to restore sensitivity to cell death. Cells were treated with a combination of tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL), which …

Amifostine Enhancement Of The Anti-Cancer Effects Of Paclitaxel In Endometrial Cancer Is Tp53-Dependent, W. Luo, F. Wu, R. Elmaoued, B. Beck, E. Fischer, Xiangbing Meng, Kimberly Leslie, Donghai Dai

Kimberly K. Leslie

Endometrial cancer (ECa) is the fourth most common malignancy in women. Currently, there is no effective therapy for advanced and recurrent cancer. Among the poor-outcome endometrial cancers, there is a high frequency of TP53 mutations. We have previously reported that amifostine has a direct anti-cancer effect and has a significant synergistic effect with paclitaxel when used in endometrial cancer cell and xenograft models. In this report, using a cell line with knock-down p53 expression through siRNA, we found that amifostine enhancement of paclitaxel's anticancer effect is p53 status-dependent. Amifostine promotes entry into the G2-M phase through regulation of cyclin-dependent kinase-1 …

Consequences Of The Loss Of P53, Rb1, And Pten: Relationship To Gefitinib Resistance In Endometrial Cancer, L. Albitar, M. Carter, S. Davies, Kimberly Leslie

Kimberly K. Leslie

OBJECTIVE: These studies demonstrate how loss of function mutations or downregulation of key tumor suppressors missing from type I and type II endometrial cancer cells contributes to carcinogenesis and to resistance to the EGFR inhibitor gefitinib (ZD1839). METHODS: Cell models devoid of tumor suppressors PTEN and RB1 or PTEN were studied. PTEN, RB1 and p53 expression was reinstated, and the effects on cell cycle, apoptosis, and cell cycle regulators were evaluated. RESULTS: In Ishikawa H cells that model type I endometrial cancer in the loss of PTEN and RB1, re-expressing PTEN and RB1 increased the apoptotic and G1 phases and …