1,720,982 research outputs found
Spy1 and Hepatocellular Carcinoma Progression: Exploring a Link in a Murine Model
No full textPrimary liver cancer represents one of the fastest rising cancers in Canada. The increasing incidence of this pluralistic and multi-faceted malignancy make having a full understanding of the disease an essential step when considering treatment options. The most common type of liver cancer, hepatocellular carcinoma (HCC), may stem from a variety of lifestyle factors and circumstances. Cirrhosis and advanced fibrosis of the liver are two common causes. These chronic disease states are often associated with alcoholism, but can also arise due to non-alcoholic steatohepatitis (NASH) and fatty liver disease. Hepatitis and fatty liver elicit liver cell injury, inflammation and oxidative damage, which in turn activate the liver's regenerative processes. Regeneration, especially when continually called upon, represents a proliferative process that may render patients susceptible to HCC. Spy 1 is a cyclin-like protein that promotes cell cycle progression and drives cell growth during select regenerative processes. A serendipitous finding in mice developed to study the role of Spy1 in the mammary gland revealed that the male Spy1 mice had significantly more primary HCC than their littermate controls. To further explore the role of Spy1 in HCC, NASH has been initiated in wild-type mice using a methionine-choline deficient diet. Spy1 levels and inflammatory, proliferative and regenerative responses are being monitored by analyzing gene expression, protein levels, fat accumulation and morphological changes. This data will determine the physiological processes that correlate with elevated Spy1 levels during liver injury and regeneration. The resulting information will aid in establishing a causal link in the progression of HCC. Future work will determine whether this mechanism represents a target for treatment for patients with this aggressive form of cancer
The Role of the Cyclin-like Protein, Spy1, on Cell Cycle Progression and Liver Cancer
No full textViable, Healthy and Safe CommunitiesHepatocellular carcinoma (HCC) is the cause of approximately 1 million deaths per year, and accounts for 85-90% of all primary liver cancers. Its presence has been observed worldwide, survival rates are poor, and many risk factors put individuals at a higher chance of developing this disease. Effective therapies are limited leading to poor 5-year survival. The primary cell type of the liver, hepatocytes, display unique cell growth and proliferation properties. Hepatocytes become polyploid through development, which increases the DNA content in each cell, and they retain the potential to regenerate and proliferate. Increased polyploidy has been shown to be a protective factor in the development and progression of HCC. Misregulation of the cell cycle plays a critical role in the onset of HCC. Spy1 is an atypical cyclin-like protein that can induce progression through the cell cycle by binding to cyclin-dependent kinases (CDKs). This binding allowing for unique progression through various cell cycle checkpoints, and Spy1 is known to be elevated in HCC. A transgenic mouse model, MMTV-Spy1, that has decreased hepatocyte ploidy and increased susceptibility to liver tumour formation, will be utilized to study the effects of increased expression of Spy1 on hepatocyte regeneration, susceptibility to tumour formation and response to treatment. Expression of mediators of cell cycle progression, differentiation and metabolism in hepatocytes, such as p53, CCAAT/enhancer binding proteins (C/EBP), cyclin D and p27, will be examined. The results will provide insight into the effects that Spy1 has on cell cycle progression in hepatocytes, and may reveal a novel therapeutic target in the treatment of HCC
The influence of drug treatment timing in triple-negative breast cancer
No full textBreast cancer is one of the most common types of cancer found in women, with 10-15% of these cases being triple-negative breast cancer (TNBC). TNBC is identified as lacking three receptors (estrogen receptor, progesterone receptor, and HER2) that are used in target therapy in breast cancer. Due to the lack of these receptors, generalized chemotherapy treatments must be used instead. The standard of care for TNBC includes three drugs (adriamycin and cyclophosphamide (AC), and paclitaxel (T)) that target certain areas of the cell and promote cell death. A fourth drug, carboplatin (Ca), can also be used in combination with paclitaxel in TNBC treatments. The purpose of this study was to determine how the order of drug treatments influence cell cycle and cell death rates of TNBC, and to determine the administrative timing of treatments that result in the highest efficacy. MDA-MB-231 and MDA-MB-468 cell lines were used and treated with AC, T, T+Ca, or Ca at various time points. Cell cycle analysis and proliferation rates were determined using flow cytometry and Trypan Blue exclusion assay. Results demonstrated that a specific patterns of drugs (T/T+Ca) result in the lowest amount of live cells, indicating the cells responsiveness to treatments. This study can help to identify the most effective timing of TNBC drug treatments to increase the efficacy of treatments which may help increase the 5-year survival rate of patients with TNBC
Role of Spy1 in Mammary Development
No full textViable, Healthy and Safe CommunitiesBreast cancer accounts for 25% of all new cancer cases in women and 13% of all cancer deaths in women. Determining the key mediators that regulate aspects of both normal and abnormal development of the breast is crucial to the development of better diagnostics and treatment options. Proper cell cycle regulation guides cellular changes during the stages of mammary development, and misregulation or mutation/deletion of key cell regulatory genes represents an important step in breast cancer initiation and progression. The cyclin-like protein Spy1 is tightly regulated during normal mammary gland development and has been implicated in several cancers, including breast cancer. Spy1 binds and activates cyclin-dependent kinases (Cdks), promoting progression through the G1/S and G2/M phase of the cell cycle. Elevated levels of Spy1 significantly increases cell proliferation and has been shown to override the DNA damage response. This study seeks to explore the question - Is Spy1 required for normal and abnormal development of the breast? My thesis work involved using the novel genome-editing tool CRISP-Cas9 to knockout Spy1 in the mouse mammary epithelial cell line HC11 and the breast cancer cell line, MDA-MB 231. These knockout cells were tested for effects on mammary cell growth and development such as proliferation, differentiation, stem cell expansion and migration. My results support that this unique family of cell cycle regulators play a critical role in the differentiation and stem cell maintenance in the mammary gland. This work sheds light on the mechanisms of normal mammary development as well as breast cancer initiation and progression and supports further exploration of this mechanism as a therapeutic direction for breast cancer
Comparison of hepatic gene expression profiles between cirrhotic and non-cirrhotic HCC
No full textHepatocellular carcinoma (HCC) ranks among the leading causes of cancer-related deaths globally. Metabolic Associated Steatotic Liver Disease (MASLD), the most prevalent liver condition, is closely linked to a spectrum of hepatic disorders, including Metabolic Associated Steatohepatitis (MASH), liver cirrhosis, and eventually HCC. While cirrhosis is a well-established precursor to HCC, approximately 20% of HCC cases arise without prior cirrhosis, and the molecular mechanisms driving this subset of non-cirrhotic HCC remain poorly understood. This study employs a comprehensive bioinformatics approach to investigate the distinct molecular drivers of non-cirrhotic HCC compared to cirrhotic HCC. This study analyzed mRNA expression datasets to identify differentially expressed genes (DEGs) in MASLD/MASH versus normal tissue and cirrhotic and non-cirrhotic HCC versus normal tissue. GO analysis revealed that the DEGs were involved in pathways regulating lipid metabolism, cell proliferation, adhesion, migration, and immune responses, highlighting their diverse roles in tumorigenesis. Core genes involved in cell cycle regulation were identified and their expression patterns were systematically compared across MASLD/MASH, cirrhotic HCC, and non-cirrhotic HCC groups. Key genes such as CCNB1, E2F2, CDC25A, CCNE1, CDK1, CDKN2A, and CDKN2B showed significant upregulation in non-cirrhotic HCC compared to cirrhotic HCC, suggesting roles in driving tumorigenesis independent of cirrhosis. This comprehensive bioinformatics analysis identified core genes that mediate the molecular mechanisms underlying MASLD and MASH and their potential roles in non-cirrhotic HCC development. These findings provide a deeper understanding of the molecular basis of non-cirrhotic HCC and highlight promising biomarkers and therapeutic targets for diagnosing and managing this subset of HCC
Treatment Timing of Triple-Negative Breast Cancer
No full textBreast cancer is the second highest cause of death from cancer in Canada. Triple-negative breast cancer (TNBC) accounts for 10-15% of all cases and has a poorer prognosis than other breast cancer subtypes. TNBC lacks expression of the estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2 (HER2), which are common therapeutic targets in breast cancer. The standard of care for treatment of TNBC instead consists of adriamycin (A), paclitaxel (T), carboplatin (Ca), and cyclophosphamide (C), to target various aspects of the cell cycle in order to induce cell cycle arrest. Timing of administration may affect cell cycle arrest, and alterations in cell cycle mediators may also influence the efficacy of treatment. The purpose of this study was to determine how the addition and timing of treatments influence the cell cycle and how this knowledge can be used to help determine more effective timing of treatment administrations. MDA-MB-231 TNBC cells were treated with AC, T, T+Ca, or Ca at various time points. Flow cytometry and Trypan Blue exclusion assay were used to determine cell cycle progression and proliferation rate. It was found that different combinations of drugs resulted in the arrest of cells at various phases of the cell cycle which may affect responsiveness to subsequent treatments. This information can be used to help determine the most effective timing of treatment and may help improve the 5-year survival rate of patients with TNBC
Spy1: A Closer Look at its Binding Mutants
No full textBreast cancer is the second leading cause of death from cancer among Canadian women, taking the lives of fourteen women each day in Canada. Spy1 (SPEEDY; RINGO) has been previously identified as a novel cell-cycle regulator that is elevated in many breast cancer patients, promoting progression through the cell-cycle and increased cell proliferation. Spy1 is an atypical, cyclin-like protein that is capable of binding directly to Cdk1 and Cdk2, activating their kinase activity to override cell-cycle checkpoints. Spy1 can also promote the degradation of p27, a Cdk inhibitor, through its phosphorylation and binding with Spy1. The mechanism by which Spy1 activates Cdks has been resolved using only Cdk2 and Spy1A, a single member within the Spy1 family. Mutation of D90 reduces binding to Cdk2, whereas the mutation of D97 and E135 on Spy1A were shown to impair the ability of Spy1 to activate Cdk2. Mutating the residues R170/174 and R179/180 reduced its binding with p27, leading to increased p27 expression. There is interest in determining whether these residues are conserved across Spy1 family members and further resolving the impact these mutations have on Spy1 function. We expressed these mutants in HEK-293 cells in the presence and absence of p27 to examine the effects of these mutants on cell growth and binding to its effectors. To investigate sequence homology between the different Spy1 family members, their amino acid sequences were aligned and compared using Basic Local Alignment Search Tool (BLAST). Future work can be done to examine whether the function of these sites is conserved across the family members. Given the involvement of Spy1 in many types of cancer, including more aggressive forms like triple negative breast cancer, the fulfillment of these objectives will provide a better understanding of the protein and the potential for it to be targeted in anti-cancer therapies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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