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Autophagy In Life and Disease. By: LaShanale Wallace. Overview. Introduction: What is Autophagy? Objective Specific examples Conclusion. What is autophagy…. A vital cellular process by which intracellular components are degraded within the lysosome - PowerPoint PPT Presentation
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By: LaShanale Wallace
Introduction: What is Autophagy?
Objective
Specific examples
Conclusion
A vital cellular process by which intracellular components are degraded within the lysosome
An essential for survival, differentiation, development, and homeostasis
Is to ensure cell survival through unfavorable situations ex….
Nutrient absenceGrowth factor withdrawAbundant amount of toxic proteinsDefected organells
The Roles of Autophagy in life and disease
Focusing on the dual roles of autophagy
Specific examples are…
1. Its role as cytoprotective autophagy
2. Its role in skeletal muscle and aging
3. And its role in pancreatic cancer
Purpose Investigate expression pattern and
sublocalization of caspase 8 in TRAIL mediated autophagy
Expression of caspase 8 in shift from autophagy to apoptosis
Materials HCT colon carcinoma cells treated with
TRAIL
Method Quantitative
image cytometry,
Confocal microscopy assay.
Immunoblot
Inhibition of autophagy induces caspase 8 activity
Cleaved caspase 8 localizes to autophagosome, inhibiting apoptosis
This study provides evidence for regulation of caspase 8 activity through autophagy
Capase 8 provides a cross talk mechanism between autophagy and apoptosis
PurposeDoes autophagy in
skeletal muscle change with age?
Does exercise and calorie restriction have an effect on autophagy?
Materials Male Fisher RatsAd libthium dietFour groups: Y,O,
OCR, and OCREXFast twitch muscle
tissue
Results Autophagy decreases with age.
Calorie restriction increased autophagy response
Exercise had no significant effect
Age is associated with lower levels of autophagy. This leads to increased cellular damage and apoptosis causing muscle loss.
Mild calorie restricted diets increased
autophagy in older rats, protecting muscle from cell damage and death
PurposeDemonstrate that pancreatic cancers are dependent on autophagy for growth
Pancreatic tumor cells are sensitive to autophagy inhibition
Pancreatic ductal adenocarcinoma cells(PDAC)
Control cell lines MCF7, H460, AND HPDE
GFP-LC3 assay Chloroquine
inhibitor
Assay determined degree of autophagy
Immunochemistry monitored LC3 expression during tumor progression
CQ Treatment
PDAC has high levels of basal autophagy Autophagy is upregulated during tumor
progression PDAC is sensitive to CQ treatment PDAC Mice treated with CQ live longer
Since PDAC is dependent on autophagy, this provides a potential target for therapeutic intervention
Since chloroquine is already used as a anti-malaria therapeutic, clinical trials using drugs targeting autophagy inhibition are strongly suggested for pancreatic cancer
Functions of autophagy can be beneficial are harmful
Its role to promote cell survival…. Is beneficial in life processes such as
aging Harmful in diseases like pancreatic cancer
With knowledge researchers can create therapeutics and either inhibit or increase autophagy pathways for more favorable outcomes.
Dr. Muganda MARC Program Dr. White Mrs. Petty Mrs. Sindy Martin
1. Wohlgemuth, S. E., Seo, A. Y., Marzetti, E., Lees, H. A., and Leeuwenburgh, C. Skeletal muscle autophagy and apoptosis during aging: effects of calorie restriction and life-long exercise. Experimental Gerontology 2010; 45: 138-148.
2. Young M, T. Y., Khan O, Park S, Hori T, Yun J, Amin S, Hu C, Zhang J, Kester M, and Wang H. Autophagosomal membrane serves as a platform for an intracellular death-inducing signaling complex (iDISC)-mediated caspase-8 activation and apoptosis. The Journal of Biological Chemistry. 2012; 287: 12455-12468.
3. Rosenfeldt MT, Ryan KM. The multiple roles of autophagy in cancer. Carcinogenesis. 2011; 32(7): 955-963.
4. http://tp-apg.genes.nig.ac.jp/autophagy/5. http://www.wormbook.org/chapters/www_autophagy/
autophagy.html6. http://www.invitrogen.com/site/us/en/home/References/
Molecular-Probes-The-Handbook/Assays-for-Cell-Viability-Proliferation-and-Function/Assays-for-Apoptosis.html#head7
7. http://beaker.sanfordburnham.org/2011/09/autophagy-101/