November 2012


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Biosciences Graduate Students <[log in to unmask]>
"Diane St. Germain" <[log in to unmask]>
Thu, 1 Nov 2012 10:33:50 -0400
To: Biology Graduate Students <[log in to unmask]>, BINF Students <[log in to unmask]>, SSB Faculty <[log in to unmask]>, [log in to unmask]
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Dissertation Defense Announcement
To:  The George Mason University Community

*Candidate: Yvette Connell-Albert
Program:    PhD Biosciences*

*Date:   Tuesday November 13, 2012
Time:   11:00 a.m.
Place:  George Mason University
           The Hub (SUB II) Meeting Room 5
           Fairfax Campus 
Dissertation Director: Dr. Karlyne Reilly
Committee Chair: Dr. Ancha Baranova
Committee members: Dr. Daniel N. Cox, Dr. James D. Willett, Dr. Barney 

*Title: "Aberrant Signaling in Astrocytomas and Glioblastoma Multiforme 
(GBM):  Utilizing
Inhibitors of Proliferation as Potential Therapies"*

The dissertation is on reserve in the Johnson Center Library, Fairfax 
The doctoral project will not be read at the meeting, but should be read 
in advance.

All members of the George Mason University community are invited to attend.

Glioblastomas (GBMs), the most aggressive malignant astrocytomas, are 
recurrent, infiltrative, and fatal. In GBMs, receptor tyrosine kinases 
(RTKs) are often activated by mutations, leading to the dysregulation of 
cell signaling pathways. The PI3K/Akt1/mTOR pathway, which plays a role 
in many biological processes such as proliferation, survival, invasion, 
migration and angiogenesis, is often deregulated in malignant cancers, 
often by the simultaneous loss of tumor suppressor PTEN, and the 
hyperactivation of the kinase Akt. Therefore, pharmacological inhibition 
of the PI3K/Akt1/mTOR pathway may prove beneficial in arresting the 
proliferation of astrocytomas and glioblastomas. In order to determine 
if the candidate molecules Choloroquine, Nelfinivir, PIA-6, OSU03012, 
Rapamycin, Tricribine (TCN), and PI-103 inhibit the PI3K/Akt-1/mTOR 
pathway, we used the Alamar blue assay as a measure of metabolic 
activity and proliferation in mouse astrocytoma cell lines K1861-10 
Grade II; KR158 Grade III; K130G#3 Grade IV; human astrocytoma cell 
lines, U87MG and SF295, both Grades IV; and normal proliferating mouse 
primary astrocytes treated with candidate molecules described above. 
Inhibitors with low IC50 values in tumor cells as compared to normal 
primary astrocytes were selected. From the select panel of inhibitors, 
only the AKT inhibitor TCN and dual PI3K/Akt-1 inhibitor PI-103 showed 
low IC50 values in the nM or pM range, suggesting strong inhibition of 
proliferation in the astrocytoma cell lines tested. Rapamycin, an mTOR 
inhibitor, showed inconsistent inhibition of cell proliferation on the 
cell lines tested, suggesting that rapamycin may be acting through more 
than one pathway. Results of our study suggest that the PI3K/Akt1/mTOR 
pathway has a potential as a druggable target in astrocytomas and