Journal Club May09
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Transcript of Journal Club May09
![Page 1: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/1.jpg)
![Page 2: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/2.jpg)
HDAC inhibitors alter gene expression
Show potent anti-tumour activities Possible use as chemotherapeutic agents
HDAC
HAT
![Page 3: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/3.jpg)
HDI Apicidin shown to induce P-glycoprotein
P-gp = Integral membrane protein involved in drug efflux and potentially multidrug resistance
Aim
Elucidate mechanism of Apicidin induced P-gpexpression
![Page 4: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/4.jpg)
Apicidin (1 induces P-gp in a cell type specific manner
• Apicidin induces P-gppromoter activity in a context independent manner
• P-gp induction not Apicidinspecific
![Page 5: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/5.jpg)
Apicidin treatment does not affect methylation status of P-gp in HeLa or KB cell lines
• No significant effect of AzadCpretreatment on P-gp activity
![Page 6: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/6.jpg)
Accumulation of acetylated histoneH3 in both responsive and non-responsive cell lines in a dose dependant manner
![Page 7: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/7.jpg)
Mithramycin, inhibitor of SP1 binding abolished Apicidin induced expression
![Page 8: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/8.jpg)
requires Y-box (NF-Y)
and GC box (SP1)
Does not require C/EBP or AP-1
![Page 9: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/9.jpg)
Confirms importance of Y-box and GC box
![Page 10: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/10.jpg)
No Change
Increase
Dissociation
Accumulation
Active transcription
![Page 11: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/11.jpg)
Inhibition of PI3K, but not other kinasepathways reduces P-gp promoter activity
![Page 12: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/12.jpg)
![Page 13: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/13.jpg)
Blocking SP1 phosphorylation by PI3K pathway inhibits dissociation of HDAC1 and recruitment of C/EBP
![Page 14: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/14.jpg)
Inactive
SP1
+ Apicidin
Activation of PI3K pathway
HDAC1
C/EBP
pCAF PolII
• Active
![Page 15: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/15.jpg)
Apicidin induces PI3K pathway,
PI3K results in phosphorylation of SP1
SP1 phosphorylation signals chromatin remodelling and activation of P-gp
This is independent of changes in methylation
![Page 16: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/16.jpg)
Effect of prolonged treatment /different dose
Change in Methylation status
Was methylation effected by Aza treatment
Range of 0.3 to 3 M
![Page 17: Journal Club May09](https://reader034.fdocuments.net/reader034/viewer/2022052400/5598ef701a28ab65118b47c2/html5/thumbnails/17.jpg)
Cell recovery after Short term treatment
Long term treatment
Effect of apicidin MDR sensitive cell lines/induction of MDR by Apicidin
Polymophisms/Translocations?
Proof of elimination of TF binding in mutants?
Binding of C/EBP pCAF to Y-box/each other
Accumulation of HDAC2 in non-responsive cell line