Medicine and Health Sciences Commons^™

Applying Mci-062, A Novel Pan-Ras Inhibitor, To Treat Kras-Mutant Lung Cancer, Richard Fu

Honors Theses

RAS is a prevalent oncogene that is mutated in 27% of human cancers. Gain-of-function RAS mutations activate multiple downstream pathways, including the RAS-RAF-MEK-ERK and PI3K/AKT/mTOR pathways, which are critical in tumorigenesis and cancer cell proliferation. RAS proteins such as KRAS, a member of the RAS protein family, and their downstream effectors are attractive targets for cancer therapy since their mutations act as frequent drivers in lung, colorectal, and pancreatic cancers. However, RAS proteins have relatively smooth surfaces that lack traditional binding pockets, making inhibitors specific to RAS difficult to create. Recently, a novel small molecule pan-RAS inhibitor named MCI-062 was …

Attenuated Bacteria Potentiate The Outcome Of Immunotherapy With Pd-L1 Blockade In A Pre-Clinical Model Of Colorectal Cancer, Besan Haytham Mohammad Al-Saafeen

Theses

After more than a century of investigation, it has become evident that cancer development and progression occur at the expense of a dysfunctional immune system. This realization has ushered cancer immunotherapy as a new modality of treatment. In the last decade, the use of immune checkpoint inhibitors to treat cancer patients resulted in unprecedented and durable clinical benefits. However, the response rate in many cancers remains rather modest, with colorectal cancer being at the lower end of the spectrum. Previous work from our laboratory demonstrated the efficacy of using attenuated bacteria as immunomodulatory anti-cancer agents. The current study investigated the …

Macrophages And Associated Inflammation Differentially Impact Obesity, Colorectal Cancer And Obesity-Enhanced Colorectal Cancer, Jackie Bader

Theses and Dissertations

Colorectal Cancer (CRC) is the third-most common malignancy for men or women, with chronic inflammation considered as a primary risk factor. Obesity is also considered a chronic inflammatory disease and is associated with increased CRC incidence. Further, obesity and CRC occur in men and women differently with the highest incidence of either disease found in men, suggesting that female sex hormones may play a protective role in inflammatory diseases. Macrophages can promote inflammation and are a driving force in obesity-associated metabolic dysfunction. Conversely, macrophages also contribute to pro-tumoral responses including, proliferation, angiogenesis and tissue remodeling. This heterogeneity of macrophage behavior …

Impact Of Kras/Nras Mutational Heterogeneity On Clinical Outcomes In Colorectal Cancer, Jonathan M. Loree

Dissertations & Theses (Open Access)

Introduction: Mutations in KRAS/NRAS (RAS) predict a lack of benefit from anti-EGFR agents in metastatic colorectal cancer (mCRC). As next generation sequencing (NGS) has advanced, we are discovering atypical and low allele frequency mutations. We aimed to evaluate how NGS can optimally define RAS mutant CRC and the role of relative mutant allele frequency (rMAF) as a biomarker.

Methods: Using institutional and public cohorts of mCRC patients with NGS results, we described the prevalence and clinical impact of atypical (not in current guidelines) and low rMAF RAS mutations (RAS MAF by the MAF of the mutated gene with …

The Influence Of Mir-99a On Mtor Signaling Regulation In Colorectal Cancer Cell Lines., Jonathan Rice

Electronic Theses and Dissertations

Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth most common cause of death. These are staggering statistics for a disease that can essentially be cured if caught early and the pathology is favorable to therapeutic intervention. There is currently a drastic decrease in five year survival as the cancer stage increases from locally confined disease to metastatic disease. These statistics suggest that although some strides have been made with colon cancer screening and early intervention, there is still much room for improvement in both screening and treatment of CRC. One of the pathways that have …

Novel Cellular Targets Of Aspirin In Chemoprevention Studies On P53, G6pd And C-Myc, Guoqiang Ai

Electronic Theses and Dissertations

Background

Aspirin has generated a significant interest in recent years as a potential chemopreventive agent supported by strong evidence from epidemiological data; however, the mechanisms are not well understood. The objective of this dissertation is to identify novel cyclooxygenase (COX)-independent pathways by which aspirin exerts its anticancer effects in epithelial cancer cell lines. We investigated the effect of aspirin on p53, glucose 6-phosphate dehydrogenase (G6PD), and c-Myc, all of which are known to play a major role in cancer development. p53 is a tumor suppressor protein, often mutated in cancers causing its inactivation. Expression of G6PD is elevated in many …

The Chemopreventive Effect Of Polymethoxyflavones: Targeting The Colorectal Cancer Stem Cells, Fei Xu

Doctoral Dissertations

Among all the cancers, the death rate of colorectal cancer is one of the highest. Evidence from both murine xenograft model and human trials have shown cancer stem cells (CSCs) are responsible for the initiation, metastasis and recurrence of multiple cancers therefore targeting colorectal CSCs would be a promising chemo-preventive/ therapeutic strategy. Polymethoxyflavones including nobiletin (NBT) and 5-demethylatednobiletin (5DN) are exclusively found in citrus peels and have been shown to have anti-cancer effects. Our previous studies in the biotransformation and tissue distribution of NBT and 5DN have shown that in order to fuller evaluate the biological impact of those two …

Methylation Of Egfr By Arginine Methyltransferase Prmt1 Enhances Egfr Signaling And Cetuximab Resistance, Hsin-Wei Liao

Dissertations & Theses (Open Access)

Protein modifications of epidermal growth factor receptor (EGFR) intracellular domain are well known regulators of EGFR functions whereas those of its extracellular domain remain relatively unexplored. Here, we report that methylation at R198 and R200 of EGFR extracellular domain by protein arginine methyltransferase 1 (PRMT1) upregulates its binding to EGF and subsequent receptor dimerization and signaling activation. Methylation-defective EGFR mutant reduced tumor growth in mouse orthotopic xenograft model. Importantly, increased EGFR methylation sustains its signaling activation and cell proliferation in the presence of therapeutic EGFR monoclonal antibody, cetuximab. EGFR methylation level also correlates with higher recurrence rate after cetuximab treatment …

Mcp-1 In Colorectal Cancer: Benefits Of Exercise, Jamie Lee Mcclellan

Theses and Dissertations

The etiology of colon cancer is a complex phenomenon that involves both genetic and environmental factors. However, only about 20% have a familial basis with the largest fraction being attributed to environmental causes that can lead to chronic inflammation. Tumors associated macrophages drive the pro-inflammatory response in the tumor micro-environment and are associated with poor prognosis in certain cancers. Monocyte chemoattractant protein 1 (MCP-1) is thought to be the most important chemokine for recruitment of macrophages to the tumor microenvironment. In chapter 1, we examined the timing and magnitude of the intestinal inflammatory cytokine response in relation to tumorigenesis in …

Clinical Consequences Of Micrornas In Colorectal Cancer, Liselle C. Bovell

All ETDs from UAB

Colorectal cancer (CRC) is a heterogeneous disease, and factors such as tumor location, the environment, genetics, and ethnic differences, can influence its development and progression. Over the last few decades, overall CRC mortality rates have declined; however, racial disparities in mortality rates have increased. The discovery of biomarkers that focus on identifying individual differences based on confounders such as tumor stage and patient race/ethnicity is needed, for such biomarkers can lead to development of personalized therapeutic approaches to target these molecules. MicroRNAs (miRNAs) are a class of small molecules that regulate genes at the post-transcriptional level. Altered miRNA expression levels …

Cyclic Gmp Phosphodiesterase As A Novel Target For Colorectal Cancer Chemoprevention, Nan Li

All ETDs from UAB

Nonsteroidal anti-inflammatory drugs (NSAIDs) display promising antineoplastic activity for colorectal and other cancers, but toxicity from cyclooxygenase (COX) inhibition limits their long-term use for chemoprevention. However, many investigators have concluded that COX-independent mechanisms are responsible for their antineoplastic activity. We previously reported that cyclic guanosine monophosphate phosphodiesterase (cGMP PDE) is a non-COX target of sulindac sulfide (SS). However, the specific isozyme families involved have not been well studied. Here we demonstrate that SS inhibits the growth of colon tumor cells through a novel mechanism involving inhibition of two cGMP degrading isozymes, PDE5 and PDE10, to activate cGMP-dependent protein kinase (PKG). …

Biochemical And Cellular Mechanisms For The Antineoplastic Properties Of Sulindac, Jason Derek Whitt

All ETDs from UAB

ABSTRACT The nonsteroidal anti-inflammatory drug (NSAID) sulindac has displayed the ability to inhibit the proliferation of colorectal cancer (CRC) cells and to increase the sensitivity of multidrug resistant (MDR) cancer cells to a wide variety of chemotherapeutic agents. The antineoplastic activity of sulindac has been attributed to inhibition of the prostaglandin producing enzyme COX-2, but the exact mechanism remains elusive and the inhibition of prostaglandin synthesis can result in gastrointestinal, hepatic, and cardiovascular toxicities. Enzymatic, cellular, and imaging assays were used to identify mechanisms that could contribute to the antiproliferative and apoptotic activity of sulindac. Screening of more than 500 …