Matching Items (6)

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Development of a new model organism in cancer research: Macrostomum lignano (Platyhelminthes)

Description

Macrostomum lignano is characterized by its elevated regenerative ability conferred by its high percentage of stem cells (the highest recorded for any animal). M. lignano is already used as a model organism for addressing fundamental questions of stem cell biology,

Macrostomum lignano is characterized by its elevated regenerative ability conferred by its high percentage of stem cells (the highest recorded for any animal). M. lignano is already used as a model organism for addressing fundamental questions of stem cell biology, aging, regeneration, and reproduction, but not yet cancer.
M. lignano larvae were isolated into separate wells of 24-well plates. After reaching maturity (30 days), the experimental plates were exposed to 5 Gys of X-rays every 4 days for a total of a 25 Gy exposure. We observed phenotypes that may be attributed to the acute effect of irradiation (e.g. blisters) but we recorded two types of phenotypes that may be a result of long-term effects of exposure to radiation. We observed enlarged testis and dark regions/masses that appeared statistically significantly more frequently in the treated animals (Fisher exact test, p=0.0026). Preliminary histological analyses of the enlarged testis suggest a benign testis enlargement due to an aberrant growth of the testes and an accumulation of aberrant spermatozoa. Importantly, we found that, similar to cancer, the dark masses can grow in size over time and the histological analysis confirms that the observed masses are composed of cells completely different from surrounding normal cells. Notably, we observed that those masses can develop and then completely disappear through an observed method of ejection. M. lignano offer the unique possibility to study in vivo cancer development in a simple organism that can easily be cultured in the lab in large numbers.

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Date Created
2020-05

CRISPR/Cas9 Mediated Mutation in the ATP-ase Domain of XPB to Study its Role in Pancreatic Ductal Adenocarcinoma

Description

Pancreatic ductal adenocarcinoma (PDAC) is a form of pancreatic cancer that affects the exocrine function of the pancreas. PDAC is often hard to diagnose and has shown to also be as difficult to treat. Xeroderma pigmentosum type B (XPB), is

Pancreatic ductal adenocarcinoma (PDAC) is a form of pancreatic cancer that affects the exocrine function of the pancreas. PDAC is often hard to diagnose and has shown to also be as difficult to treat. Xeroderma pigmentosum type B (XPB), is a protein can be found in Transcription Factor II Human (TFIIH). It is known to have ATP-ase and helicase activities. The ATP-ase activities could be used to regulate the transcription within super enhancer (SE) networks. Knocking out the ATP-ase activity in XPB in the same way that triptolide does would offer a more individualized therapeutic regiment. A loss of function mutation was tested to identify whether or not the mutation was present within the strand of DNA. In order to explore the role of XPB in pancreatic cancer, a knockout clone was made through the use of the CRISPR/Cas9 genome editing technology to induce a clone in exon 2 of XPB using a plasmid with Green Fluorescent Protein (GFP) selection marker. Once the clones were successfully made, they underwent testing through the use of a Surveyor Mutation Detection Kit for standard electrophoresis. The confirmation of a functional clone lead to GFP, which contained the mutation, being chosen for further testing be compared to the wild type GFP. After the GFP D54H mutation was chosen for further testing, it was then cultured from bacteria and wild type GFP and GFP D54H underwent a restriction enzyme digest. The digest resulted in showing that GFP and GFP D54H were the same on a larger level, and that one of the only ways to prove that the mutation was present was through amplification and analysis using the mutation detection kit.

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Date Created
2017-05

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Doxorubicin Induced Cardiotoxicity and High Intensity Aerobic Exercise

Description

Doxorubicin (DOX) is a cardiotoxic, anthracycline-based, anti-neoplastic agent that causes pathological cardiac remodeling due to altered protein expression associated with cardiotoxicity. DOX cardiotoxicity causes increased Akt phosphorylation, blunted AMPK phosphorylation and upregulated mTOR phosphorylation. Akt is activated by cellular stress

Doxorubicin (DOX) is a cardiotoxic, anthracycline-based, anti-neoplastic agent that causes pathological cardiac remodeling due to altered protein expression associated with cardiotoxicity. DOX cardiotoxicity causes increased Akt phosphorylation, blunted AMPK phosphorylation and upregulated mTOR phosphorylation. Akt is activated by cellular stress and damage. AMPK is activated by increases in AMP and ADP concentrations and decreased ATP concentration. mTOR is active in cellular growth and remodeling. These proteins are cellular kinases with cascades that are influenced by one another. Exercise preconditioning may diminish the cardiotoxic effects on these proteins. Female, Ovariectomized Sprague-Dawley rats (N=33) were randomized to: Exercise+DOX (EX+DOX, n=9); Exercise+Vehicle (EX+VEH, n=8); Sedentary+DOX (SED+DOX, n=8); and Sedentary+Vehicle (SED+VEH, n=8) groups. DOX (4mg/kg) or VEH (saline) intraperitoneal injections were administered bi-weekly (cumulative dose of 12mg/kg). VEH animals received body weight matched volumes of saline based on dosing in animals receiving DOX. Exercise (EX) animals underwent high intensity (85-95% VO2 peak) interval training (HIIT) (4x4 min bouts) separated by low intensity (50-60% VO2max) intervals (2 min bouts) 5 days per week. Exercise began 1 week prior to the first injection and was continued throughout the study. Rats were euthanized 5 days after the last injection. Left ventricular tissue was isolated, processed into lysate and used for western blot analyses [2x2 ANOVA; (α=0.05)]. DOX induced significant phosphorylation of Akt and mTOR (p=0.035; p=0.032) only in SED+DOX rats, but unchanged in EX+DOX rats. No significant differences (p=0.374) in AMPK phosphorylation were observed between groups. Exercise Preconditioning prevents some DOX-induced changes in the cardiac mTOR signaling pathway implicated in pathological remodeling.

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Date Created
2017-05

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Loss of LKB1 Leads to Increased Chemokine Secretion in Non-Small Cell Lung Cancer

Description

Non-small cell lung cancer (NSCLC) has become the leading cause of cancer-related deaths in the United States with a combined 5-year survival rate of only 16%. Even with advancements in aggressive chemotherapeutics, there has been little improvement in patient survival.

Non-small cell lung cancer (NSCLC) has become the leading cause of cancer-related deaths in the United States with a combined 5-year survival rate of only 16%. Even with advancements in aggressive chemotherapeutics, there has been little improvement in patient survival. LKB1 (liver kinase B1)/STK11 (serine-threonine kinase 11) is a tumor suppressor gene mutated in ~30% of NSCLC adenocarcinomas and loss of LKB1 is associated with a more aggressive cancer phenotype. In LKB1-deficient NSCLC, we observe significantly elevated expression and secretion of the chemokines CCL2, CCL5, and CCL20, which are involved in macrophage recruitment. Numerous studies have shown that high infiltration of a unique subset of macrophages called tumor-associated macrophages (TAMs) is associated with poor prognosis in patients with various cancers. mTORC1-HIF1-α and NFκB are two pathways that have been shown to regulate chemokine secretion and are often up-regulated in the absence of LKB1. Dosing LKB1-null cell lines with inhibitors of mTOR and NFκB in addition to silencing HIF1-α gene expression demonstrate that NFκB but not mTORC1-HIF1-α signaling may play a role in regulating chemokine secretion in LKB1-deficient NSCLC. Collectively, these results provide insight into the mechanisms responsible for the aggressive phenotype associated with LKB1-deficient non-small cell lung cancer.

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Date Created
2015-05

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Preclinical assessment of Wee1 inhibitor AZD1775 and DNA damaging agents in the chemotherapeutic treatment of esophageal adenocarcinoma with mutated TP53

Description

Background: Esophageal adenocarcinoma (EAC) is one of the only malignancies whose incidence is rising in the United States. Current multidrug treatment for EAC has considerable toxic side effects that necessitate the development of less toxic, more specific target drugs. Recent

Background: Esophageal adenocarcinoma (EAC) is one of the only malignancies whose incidence is rising in the United States. Current multidrug treatment for EAC has considerable toxic side effects that necessitate the development of less toxic, more specific target drugs. Recent large scale genomic analysis reveals that TP53 is the most frequently inactivated gene in EAC. One of the primary functions of TP53 and its gene product, the tumor suppressor p53, is in regulation of DNA repair in response to DNA damage. Inactivation of TP53 results in loss of the G1/S cell cycle checkpoint, and dependence on the G2/M checkpoint for DNA repair. Activity of cyclin-dependent kinase 1 (CDK1) is necessary for cells to exit the G2/M checkpoint and enter mitosis. Phosphorylation of CDK1 by the wee1 kinase inhibits CDK1 in response to DNA damage, allowing cells to maintain G2 arrest and repair the damaged DNA. Active in normal cells, wee1 kinase is critical in cancer cells to promote DNA repair and cell survival in response to DNA damage, particularly from commonly used DNA damaging therapies. AZD1775 is a small molecule inhibitor of wee1 kinase, currently under investigation in clinical trials. AZD1775 differentially targets cancer cells by blocking wee1 mediated inhibition of CDK1 and consequently preventing G2/M arrest in response to DNA damage. Combination of AZD1775 with DNA damaging agents is thought to push cancer cells with damaged DNA through to mitosis and initiate apoptosis instead of G2/M arrest and DNA repair. Based upon the incidence of TP53 mutation in EAC, we hypothesize that treatment with a DNA damaging agent in combination with AZD1775 will be as effective at eliciting DNA damage and cell death as the more toxic current standard of care, which is comprised of treatment with cisplatin, docetaxel, and radiation. Methods: p53 mutant EAC cell lines were dosed with cisplatin, AZD1775, and the combination of cisplatin and AZD1775, and then assayed for viability. Nude mice were implanted with p53 mutant patient derived xenograft esophageal adenocarcinoma tumors and randomized for treatment with AZD1775 alone, cisplatin and AZD1775, radiation and AZD1775, cisplatin, docetaxel, and radiation or vehicle (control). Tumor volume was measured over the five week treatment course. Results: In vitro and in vivo assays reveal a potent synergistic effect between AZD1775 and DNA damaging agents that is as efficacious as the standard of care therapy. The difference in AZD1775 sensitivity among TP53 mutant EAC cell lines indicates that TP53 alone may not be an adequate biomarker to assess for AZD1775- mediated toxicity.

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Date Created
2016-05

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Single-Cell Gene Expression in Esophageal Adenocarcinoma

Description

Esophageal adenocarcinoma (EAC) is one of the most lethal and fastest growing cancers in the United States. Its onset is commonly triggered by metaplastic transformation of normal squamous esophageal epithelial cells to Barrett's esophagus (BE) cells in response to acid

Esophageal adenocarcinoma (EAC) is one of the most lethal and fastest growing cancers in the United States. Its onset is commonly triggered by metaplastic transformation of normal squamous esophageal epithelial cells to Barrett's esophagus (BE) cells in response to acid reflux. BE patients are believed to progress through non-dysplastic metaplasia and increasing grades of dysplasia prior to EAC. Conventional cancer diagnostic tools rely on bulk-cell analyses that are incapable of identifying intratumoral heterogeneity or rare driver cells that play important roles in cancer progression. An improved single-cell method of cancer diagnosis would overcome this challenge by detecting cancer initiating cells before they progress into untreatable stages. In this study, using EAC as a model, we attempted to identify a more effective method of cancer diagnosis. We quantified the single- and bulk-cell mRNA expression of genes that have been proposed to be instrumental in the progression of EAC through BE. Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) analysis was performed on human primary cells to measure the mRNA expression levels of BE- and EAC-associated genes. Our results showed high levels of heterogeneity of CDX2 and TFF3 at the single-cell resolution in human BE and EAC samples. Additionally, while expression of VEGF is generally low at the bulk-cell level, our results showed that a few, rare cells had significantly higher VEGF expression levels than the majority of cells in the EAC sample. In conclusion, we have affirmed that EAC cancer cells, as well as BE cells, show high levels of heterogeneity. Based on the VEGF gene expression pattern, single-cell analysis could potentially be more effective for identifying rare, but essential cells for cancer progression, which could then be targeted for treatment. Future studies will focus on analyzing human samples from thousands of normal and cancer subjects to validate the use of single-cell profiling in cancer.

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Date Created
2013-12