Matching Items (6)
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- All Subjects: Breast Cancer
- Creators: Nikkhah, Mehdi
- Creators: Ankeny, Casey
- Resource Type: Text
Description
The objective of this research was to create a 3D in vitro model to mimic the native breast tumor microenvironment. Polydimethylsiloxane (PDMS) stamps and micromolding techniques were utilized to develop collagen based 3D tumor model. Geometrical design was optimized for the PDMS stamp to compartmentalize the tumor and stromal region of the 3D model. Addition of tumor and stromal cells into the platform further demonstrated the successful fabrication of the 3D model which will be used to investigate the role of stromal components on tumor growth and progression. Atomic force microscopy will also be utilized to access stromal remodeling during active invasion.
ContributorsAssefa, Eyerusalem Dibaba (Author) / Nikkhah, Mehdi (Thesis director) / Saini, Harpinder (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Breast and other solid tumors exhibit high and varying degrees of intra-tumor heterogeneity resulting in targeted therapy resistance and other challenges that make the management and treatment of these diseases rather difficult. Due to the presence of admixtures of non-neoplastic cells with polyclonal cell populations, it is difficult to define cancer genomes in patient samples. By isolating tumor cells from normal cells, and enriching distinct clonal populations, clinically relevant genomic aberrations that drive disease can be identified in patients in vivo. An in-depth analysis of clonal architecture and tumor heterogeneity was performed in a stage II chemoradiation-naïve breast cancer from a sixty-five year old patient. DAPI-based DNA content measurements and DNA content-based flow sorting was used to to isolate nuclei from distinct clonal populations of diploid and aneuploid tumor cells in surgical tumor samples. We combined DNA content-based flow cytometry and ploidy analysis with high-definition array comparative genomic hybridization (aCGH) and next-generation sequencing technologies to interrogate the genomes of multiple biopsies from the breast cancer. The detailed profiles of ploidy, copy number aberrations and mutations were used to recreate and map the lineages present within the tumor. The clonal analysis revealed driver events for tumor progression (a heterozygous germline BRCA2 mutation converted to homozygosity within the tumor by a copy number event and the constitutive activation of Notch and Akt signaling pathways. The highlighted approach has broad implications in the study of tumor heterogeneity by providing a unique ultra-high resolution of polyclonal tumors that can advance effective therapies and clinical management of patients with this disease.
ContributorsLaughlin, Brady Scott (Author) / Ankeny, Casey (Thesis director) / Barrett, Michael (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / School for the Science of Health Care Delivery (Contributor)
Created2015-05
Description
This project aims to address the current protocol regarding the diagnosis and treatment of traumatic brain injury (TBI) in medical industries around the world. Although there are various methods used to qualitatively determine if TBI has occurred to a patient, this study attempts to aid in the creation of a system for quantitative measurement of TBI and its relative magnitude. Through a method of artificial evolution/selection called phage display, an antibody that binds highly specifically to a post-TBI upregulated brain chondroitin sulfate proteoglycan called neurocan has been identified. As TG1 Escheria Coli bacteria were infected with KM13 helper phage and M13 filamentous phage in conjunction, monovalent display of antibody fragments (ScFv) was performed. The ScFv bind directly to the neurocan and from screening, phage that produced ScFv's with higher affinity and specificity to neurocan were separated and purified. Future research aims to improve the ScFv characteristics through increased screening toward neurocan. The identification of a highly specific antibody could lead to improved targeting of neurocan post-TBI in-vivo, aiding researchers in quantitatively defining TBI by visualizing its magnitude.
ContributorsSeelig, Timothy Scott (Author) / Stabenfeldt, Sarah (Thesis director) / Ankeny, Casey (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
Breast cancer is the second leading cause of disease related death in women, contributing over
40,000 fatalities annually. The severe impact of breast cancer can be attributed to a poor
understanding of the mechanisms underlying cancer metastasis. A primary aspect of cancer
metastasis includes the invasion and intravasation that results in cancer cells disseminating from
the primary tumor and colonizing distant organs. However, the integrated study of invasion and
intravasation has proven to be challenging due to the difficulties in establishing a combined tumor
and vascular microenvironments. Compared to traditional in vitro assays, microfluidic models
enable spatial organization of 3D cell-laden and/or acellular matrices to better mimic human
physiology. Thus, microfluidics can be leveraged to model complex steps of metastasis. The
fundamental aim of this thesis was to develop a three-dimensional microfluidic model to study the
mechanism through which breast cancer cells invade the surrounding stroma and intravasate into
outerlying blood vessels, with a primary focus on evaluating cancer cell motility and vascular
function in response to biochemical cues.
A novel concentric three-layer microfluidic device was developed, which allowed for
simultaneous observation of tumor formation, vascular network maturation, and cancer cell
invasion/intravasation. Initially, MDA-MB-231 disseminated from the primary tumor and invaded
the acellular collagen present in the adjacent second layer. The presence of an endothelial network
in the third layer of the device drastically increased cancer cell invasion. Furthermore, by day 6 of
culture, cancer cells could be visually observed intravasating into the vascular network.
Additionally, the effect of tumor cells on the formation of the surrounding microvascular network
within the vascular layer was evaluated. Results indicated that the presence of the tumor
significantly reduced vessel diameter and increased permeability, which correlates with prior in vivo
data. The novel three-layer platform mimicked the in vivo spatial organization of the tumor and its
surrounding vasculature, which enabled investigations of cell-cell interactions during cancer
invasion and intravasation. This approach will provide insight into the cascade of events leading up
to intravasation, which could provide a basis for developing more effective therapeutics.
40,000 fatalities annually. The severe impact of breast cancer can be attributed to a poor
understanding of the mechanisms underlying cancer metastasis. A primary aspect of cancer
metastasis includes the invasion and intravasation that results in cancer cells disseminating from
the primary tumor and colonizing distant organs. However, the integrated study of invasion and
intravasation has proven to be challenging due to the difficulties in establishing a combined tumor
and vascular microenvironments. Compared to traditional in vitro assays, microfluidic models
enable spatial organization of 3D cell-laden and/or acellular matrices to better mimic human
physiology. Thus, microfluidics can be leveraged to model complex steps of metastasis. The
fundamental aim of this thesis was to develop a three-dimensional microfluidic model to study the
mechanism through which breast cancer cells invade the surrounding stroma and intravasate into
outerlying blood vessels, with a primary focus on evaluating cancer cell motility and vascular
function in response to biochemical cues.
A novel concentric three-layer microfluidic device was developed, which allowed for
simultaneous observation of tumor formation, vascular network maturation, and cancer cell
invasion/intravasation. Initially, MDA-MB-231 disseminated from the primary tumor and invaded
the acellular collagen present in the adjacent second layer. The presence of an endothelial network
in the third layer of the device drastically increased cancer cell invasion. Furthermore, by day 6 of
culture, cancer cells could be visually observed intravasating into the vascular network.
Additionally, the effect of tumor cells on the formation of the surrounding microvascular network
within the vascular layer was evaluated. Results indicated that the presence of the tumor
significantly reduced vessel diameter and increased permeability, which correlates with prior in vivo
data. The novel three-layer platform mimicked the in vivo spatial organization of the tumor and its
surrounding vasculature, which enabled investigations of cell-cell interactions during cancer
invasion and intravasation. This approach will provide insight into the cascade of events leading up
to intravasation, which could provide a basis for developing more effective therapeutics.
ContributorsNagaraju, Supriya (Author) / Nikkhah, Mehdi (Thesis advisor) / Ebrahimkhani, Mohammad (Committee member) / Kiani, Samira (Committee member) / Arizona State University (Publisher)
Created2017
Description
The TP53 tumor suppressor gene is the most frequently mutated gene in human cancers. In the highly aggressive triple negative breast cancer (TNBC), TP53 is mutated in 80% of cases. TNBC lacks viable drug targets, resulting in a low prognosis (12.2% 5 year survivability rate). As such, the discovery of druggable targets in TNBC would be beneficial. Mutated p53 protein typically occurs as a missense mutation and often endows cancer cells with gain of function (GOF) properties by dysregulating metabolic pathways. One of these frequently dysregulated pathways is the Hippo/Yes-associated protein-1 (YAP1)/WW Domain Containing Transcription Regulator 1 (TAZ) tumor suppressor pathway. This study therefore analyzed the involvement of the Hippo/YAP1/TAZ pathway in p53-mediated breast cancer cell invasion. From an RNA-seq screen in MCF10A cell lines harboring different TP53 missense mutations, each with a differing invasive phenotype, components of the Hippo pathway were found to correlate with cell invasion. To this end, the active and inactive forms of YAP1 and TAZ were studied. Phosphorylated (inactive) YAP1 and TAZ are retained in the cytoplasm and eventually degraded. Unphosphorylated (active) YAP1 and TAZ translocate to the nucleus to activate TEAD-family transcription factors, inducing cell survival and proliferation genes leading to increased cell invasion. Using quantitative western blot analysis, it was found that inactive TAZ expression was lower in the most invasive cell lines and higher in the least invasive cell lines (p = 0.003). Moreover, the ratio of inactive TAZ protein to total TAZ protein was also shown to be predominantly lower in the invasive cell lines compared to the non-invasive lines (p = 0.04). Finally, active TAZ expression was primarily higher in p53-mutant invasive cell lines and lower in non-invasive p53 mutant cells. Additionally, although YAP1 and TAZ are thought to be functionally redundant, the pattern seen in TAZ was not seen in the YAP1 protein. Taken together, the results demonstrated here suggest that TAZ holds a more dominant role in governing TNBC cell invasion compared to YAP1 and further highlights TAZ as a potential therapeutic target in TNBC.
ContributorsGrief, Dustin (Author) / LaBaer, Joshua (Thesis advisor) / Anderson, Karen (Committee member) / Nikkhah, Mehdi (Committee member) / Arizona State University (Publisher)
Created2022
Description
Stromal cells play an important role in facilitating disease progression of ductal carcinoma. Cancer associated fibroblasts (CAFs) are an important component of the extracellular matrix (ECM) which constitutes the microenvironment of breast tumor cells. They are known to participate in chemotherapeutic drug resistance by modulating various biochemical and biophysical factors that contribute to increased matrix stiffness and collagen I density of the tumor-adjacent stroma. To address these issues in terms of patient treatment, anti-cancer drug regimes have been assembled to incorporate both chemotherapeutic as well as anti-fibrotic drugs to both target tumor cells while also diminishing the elastic modulus of the microenvironment by targeting CAFs. The quantitative assessment of these drug regimes on tumor progression is missing in terms of CAFs role alone.
A high density 3D tumor model was utilized to recapitulate the tumor microenvironment of ductal carcinoma in vitro. The tumor model consisted of MDA-MB-231 tumors seeded within micromolded collagen wells, chemically immobilized upon a surface treated PDMS substrate. CAFs were seeded within the greater collagen structure from which the microwells were formed. The combinatorial effect of anti-fibrotic drug (Tranilast) and chemotherapy drug (Doxorubicin) were studied within 3D co culture conditions. Specifically, the combinatorial effects of the drugs on tumor cell viability, proliferation, and invasion were examined dynamically upon coculture with CAFs using the microengineered model.
The results of the study showed that the combinatorial effects of Tranilast and Doxorubicin significantly decreased the proliferative ability of tumor cells, in addition to significantly decreasing the ability of tumor cells to remain viable and invade their surrounding stroma, compared to control conditions.
A high density 3D tumor model was utilized to recapitulate the tumor microenvironment of ductal carcinoma in vitro. The tumor model consisted of MDA-MB-231 tumors seeded within micromolded collagen wells, chemically immobilized upon a surface treated PDMS substrate. CAFs were seeded within the greater collagen structure from which the microwells were formed. The combinatorial effect of anti-fibrotic drug (Tranilast) and chemotherapy drug (Doxorubicin) were studied within 3D co culture conditions. Specifically, the combinatorial effects of the drugs on tumor cell viability, proliferation, and invasion were examined dynamically upon coculture with CAFs using the microengineered model.
The results of the study showed that the combinatorial effects of Tranilast and Doxorubicin significantly decreased the proliferative ability of tumor cells, in addition to significantly decreasing the ability of tumor cells to remain viable and invade their surrounding stroma, compared to control conditions.
ContributorsSilva, Casey Rudolph (Author) / Nikkhah, Mehdi (Thesis director) / Saini, Harpinder (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05