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Full-Text Articles in Cell Biology

Defining Sites Of Replication Fork Collapse Caused By Atr Inhibition, Nishita Kalpendu Shastri Jan 2017

Defining Sites Of Replication Fork Collapse Caused By Atr Inhibition, Nishita Kalpendu Shastri

Publicly Accessible Penn Dissertations

DEFINING SITES OF REPLICATION FORK COLLAPSE CAUSED BY ATR INHIBITION

Nishita K. Shastri

Eric J. Brown

Replication stress, characterized by stalling of DNA replication and the accumulation of abnormal replication intermediates, has been linked to the genomic instability observed in cancer. Previous studies have defined specific genomic sequences that are difficult to replicate to be more vulnerable to replication-associated breaks and rearrangements. However, many of these sequences have been identified through indirect and potentially biased approaches. To identify DNA sequences that contribute to replication-associated genomic instability, I will describe genome-wide screens I have performed to determine the location, sequence, and ...


Extracellular Matrix Regulates Fibroblast Heterogeneity And Tumorigenesis, Diana Leigh Avery Jan 2017

Extracellular Matrix Regulates Fibroblast Heterogeneity And Tumorigenesis, Diana Leigh Avery

Publicly Accessible Penn Dissertations

Heterogeneous activated fibroblasts that deposit and remodel extracellular matrix (ECM) comprise desmoplasia, a key regulator of tumor development. The divergent outcomes in response to varied therapies targeting intratumoral desmoplasia underscore the pressing need to delineate the intricate role of a heterogeneous stroma in tumorigenesis. Fibroblast activation protein (FAP) and alpha-smooth muscle actin (╬▒SMA) identify distinct, yet overlapping, activated fibroblast subsets in myriad tumor types, fibrosis, and wound healing. FAPHi reactive fibroblasts and ╬▒SMAHi myofibroblasts can exert divergent influences on tumor progression. However, the factors that drive this phenotypic heterogeneity and the unique functional roles of these distinct phenotypes are not ...


Role Of Ceramide Kinase In Breast Cancer Progression, Ania Warczyk Payne Jan 2014

Role Of Ceramide Kinase In Breast Cancer Progression, Ania Warczyk Payne

Publicly Accessible Penn Dissertations

Recurrent breast cancer is typically an incurable disease and, as such, is disproportionately responsible for deaths from this disease. Recurrent breast cancers arise from the pool of disseminated tumor cells (DTCs) that survive adjuvant or neoadjuvant therapy, and patients with detectable DTCs following therapy are at substantially increased risk for recurrence. Consequently, the identification of pathways that contribute to the survival of breast cancer cells following therapy could aid in the development of more effective therapies that decrease the burden of residual disease and thereby reduce the risk of breast cancer recurrence. We now report that Ceramide Kinase (Cerk) is ...


The Multifunctional Protein Daxx: Studies Of Its Biology And Regulation, And Discovery Of A Novel Function, Trisha Agrawal Jan 2013

The Multifunctional Protein Daxx: Studies Of Its Biology And Regulation, And Discovery Of A Novel Function, Trisha Agrawal

Publicly Accessible Penn Dissertations

Daxx, a multifunctional protein with a diverse set of proposed functions, is ubiquitously expressed and highly conserved through evolution. A primarily nuclear protein, Daxx is able to regulate apoptosis, transcription, and cellular proliferation. Despite many studies into the function of Daxx, its precise role in the cell remains enigmatic. Herein, evidence is presented to expand upon the known anti-apoptotic function of Daxx, to establish Daxx as a novel molecular chaperone, and to further its repertoire of transcriptional targets. As an apoptotic inhibitor, Daxx is known to regulate p53 by stabilizing its main negative regulator, Mdm2, via formation of a ternary ...


Role Of Rap Signaling In The Regulation Of Erk Activation And Cell-Cell Adhesion, Lisa A. Vuchak May 2011

Role Of Rap Signaling In The Regulation Of Erk Activation And Cell-Cell Adhesion, Lisa A. Vuchak

Publicly Accessible Penn Dissertations

Rap is a member of the Ras family of small GTPases. Mammalian Rap proteins regulate many biological processes including cell and matrix adhesion, migration, proliferation, cytoskeletal dynamics, cell polarity and secretion. Rap1 is activated by TSH and cAMP in thyroid cells independently of PKA. TSH regulates differentiated gene expression and proliferation. Many of these effects are mediated through PKA. There is disagreement as to whether cAMP signaling through Rap contributes to any of the cellular effects of TSH. Given that thyroid cells express high levels of B-Raf and that Rap1 activates ERK through B-Raf in many cells, we investigated whether ...