Medicine and Health Sciences Commons^™

Mechanisms Of Therapeutic Resistance In Castration Resistant Prostate Cancer, Sarah Katherine Martin

Theses and Dissertations--Molecular and Cellular Biochemistry

Taxane based chemotherapy is an effective treatment for castration-resistant prostate cancer (CRPC) via stabilization of microtubules. Progression to castration-resistant prostate cancer is characterized by increased androgen receptor (AR), elevated intra-prostatic androgens and activated AR signaling despite castrate levels of androgens.

Previous studies identified that the inhibitory effect of microtubule targeting chemotherapy on AR activity was conferred by interfering with AR intracellular trafficking. The N-terminal domain (NTD) of AR was identified as a tubulin interacting domain that can be effectively targeted by the novel small molecular inhibitor, EPI. Taken together, this evidence provided the rationale that targeting AR nuclear translocation and …

The Effects Of Rhamm On Cell Division, Cell Motility, And Tumorigenesis, Sallie Elhayek

Electronic Thesis and Dissertation Repository

Overexpression of a RHAMM isoform (RHAMM^Δ163) transforms fibroblasts but the mechanisms underlying this oncogenic function are not well understood. RHAMM^Δ163 binds to the mitotic spindle and centrosomes via a C-terminal leucine zipper; these interactions are predicted to regulate genomic stability and cell polarity and proposed to account for the oncogenic function of RHAMM^Δ163. We hypothesized that RHAMM leucine zipper maintains mitotic spindle integrity and impacts directional cell migration through its interactions with microtubule and centrosome structures. The consequences of a mutated leucine zipper on cell division, cell motility, and tumorigenesis were assessed. Although mutant RHAMM …

Stag2 Promotes Error Correction In Mitosis By Regulating Kinetochore–Microtubule Attachments, Marianna Kleyman, Lilian Kabeche, Duane A. Compton

Dartmouth Scholarship

Mutations in the STAG2 gene are present in ∼20% of tumors from different tissues of origin. STAG2 encodes a subunit of the cohesin complex, and tumors with loss-of-function mutations are usually aneuploid and display elevated frequencies of lagging chromosomes during anaphase. Lagging chromosomes are a hallmark of chromosomal instability (CIN) arising from persistent errors in kinetochore-microtubule (kMT) attachment. To determine whether the loss of STAG2 increases the rate of formation of kMT attachment errors or decreases the rate of their correction, we examined mitosis in STAG2-deficient cells. STAG2 depletion does not impair bipolar spindle formation or delay mitotic progression. Instead, …

The Human Rna Polymerase Ii-Associated Factor 1 (Hpaf1): A New Regulator Of Cell-Cycle Progression., Nicolas Moniaux, Christophe Nemos, Shonali Deb, Bing Zhu, Irena Dornreiter, Michael A. Hollingsworth, Surinder K. Batra

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND: The human PAF (hPAF) complex is part of the RNA polymerase II transcription apparatus and regulates multiple steps in gene expression. Further, the yeast homolog of hPaf1 has a role in regulating the expression of a subset of genes involved in the cell-cycle. We therefore investigated the role of hPaf1 during progression of the cell-cycle.

METHODOLOGY/FINDINGS: Herein, we report that the expression of hPaf1, a subunit of the hPAF complex, increases with cell-cycle progression and is regulated in a cell-cycle dependant manner. hPaf1 specifically regulates a subclass of genes directly implicated in cell-cycle progression during G1/S, S/G2, and G2/M. …

Hsp27 Anti-Sense Oligonucleotides Sensitize The Microtubular Cytoskeleton Of Chinese Hamster Ovary Cells Grown At Low Ph To 42 Degrees C-Induced Reorganization, Michael T. Hargis, C. W. Storck, Eric Wickstrom, Leonid A. Yakubov, Dennis B. Leeper, Ronald A. Coss

Department of Biochemistry and Molecular Biology Faculty Papers

Chinese hamster ovary (CHO) cells maintained in vitro at pH 6.7 were used to model cells in the acidic environment of tumours. CHO cells grown at pH 6.7 develop thermotolerance during 42 degrees C heating at pH 6.7 and their cytoskeletal systems are resistant to 42 degrees C-induced perinuclear collapse. Hsp27 levels are elevated in cells grown at pH 6.7 and are further induced during 42 degrees C heating, while Hsp70 levels remain low or undetectable, suggesting that Hsp27 is responsible for some of the novel characteristics of these cells. An anti-sense oligonucleotide strategy was used to test the importance …

Analysis Of Mitotic Microtubule-Associated Proteins Using Mass Spectrometry Identifies Astrin, A Spindle-Associated Protein, Gary J. Mack, Duane A. Compton

Dartmouth Scholarship

We purified microtubules from a mammalian mitotic extract and obtained an amino acid sequence from each microtubule-associated protein by using mass spectrometry. Most of these proteins are known spindle-associated components with essential functional roles in spindle organization. We generated antibodies against a protein identified in this collection and refer to it as astrin because of its association with astral microtubule arrays assembled in vitro. Astrin is approximately 134 kDa, and except for a large predicted coiled-coil domain in its C-terminal region it lacks any known functional motifs. Astrin associates with spindle microtubules as early as prophase where it concentrates at …