Biology & Sustainability
Cell Migration and Microfilament Organization in Acute Camptothecin Treated Mouse Embryo Fibroblasts
Document Type
Oral Presentation
Location
Indianapolis, IN
Subject Area
Biology & Sustainability
Start Date
11-4-2014 1:15 PM
End Date
11-4-2014 2:45 PM
Sponsor
Mary Ritke (University of Indianapolis)
Description
The quinolone alkaloid camptothecin (CPT) is a natural product of the bark and stem of the Chinese Happy Tree, Camptotheca acuminate. As a potent topoisomerase I inhibitor, CPT causes downstream inhibition of DNA replication and RNA transcription, extensive DNA damage, and ultimately death by apoptosis. Synthetic derivatives of CPT have been found to be effective anticancer drugs. Prolonged exposure to any cytotoxic drug, including CPT and its derivatives, often leads to selection of drug-resistant cells. Using tumor cells as model systems to clearly understand the progression of cells from CPT-sensitivity to CPT-resistance is complicated by the many genetic abnormalities found in these cells. Therefore, we have attempted to isolate CPT-resistant genetically stable cells. While selecting mouse embryo fibroblasts (MEFs) resistant to CPT, past members of our laboratory observed morphological changes in the CPT-resistant monolayers. Compared to sensitive MEF cells, changes in resistant cells included a slightly diminished rate of cell migration, and diminished microfilament alignment in the lamellipodia (leading edges) of many migrating cells. To determine if the observed changes in migration and microfilament organization were induced by CPT, the effects of acute CPT exposure on MEF migration and microfilament organization were studied. A 48-hour treatment of MEF with doses of CPT that inhibit proliferation >45% (as measured by MTT assays) did not significantly affect cell migration (as measured by scratch wound analysis) or qualitatively affect the alignment and distribution of microfilaments (observed by phalloidin staining and fluorescence microscopy). We conclude that CPT treatment does not affect the dynamics of microfilament organization, and that prior observations of altered lamellipodia were likely due to other genetic and/or physiological changes that occurred during prolonged selection of CPT-resistant cells. Research supported by Department of Biology and the Honors College, University of Indianapolis.
Cell Migration and Microfilament Organization in Acute Camptothecin Treated Mouse Embryo Fibroblasts
Indianapolis, IN
The quinolone alkaloid camptothecin (CPT) is a natural product of the bark and stem of the Chinese Happy Tree, Camptotheca acuminate. As a potent topoisomerase I inhibitor, CPT causes downstream inhibition of DNA replication and RNA transcription, extensive DNA damage, and ultimately death by apoptosis. Synthetic derivatives of CPT have been found to be effective anticancer drugs. Prolonged exposure to any cytotoxic drug, including CPT and its derivatives, often leads to selection of drug-resistant cells. Using tumor cells as model systems to clearly understand the progression of cells from CPT-sensitivity to CPT-resistance is complicated by the many genetic abnormalities found in these cells. Therefore, we have attempted to isolate CPT-resistant genetically stable cells. While selecting mouse embryo fibroblasts (MEFs) resistant to CPT, past members of our laboratory observed morphological changes in the CPT-resistant monolayers. Compared to sensitive MEF cells, changes in resistant cells included a slightly diminished rate of cell migration, and diminished microfilament alignment in the lamellipodia (leading edges) of many migrating cells. To determine if the observed changes in migration and microfilament organization were induced by CPT, the effects of acute CPT exposure on MEF migration and microfilament organization were studied. A 48-hour treatment of MEF with doses of CPT that inhibit proliferation >45% (as measured by MTT assays) did not significantly affect cell migration (as measured by scratch wound analysis) or qualitatively affect the alignment and distribution of microfilaments (observed by phalloidin staining and fluorescence microscopy). We conclude that CPT treatment does not affect the dynamics of microfilament organization, and that prior observations of altered lamellipodia were likely due to other genetic and/or physiological changes that occurred during prolonged selection of CPT-resistant cells. Research supported by Department of Biology and the Honors College, University of Indianapolis.