Journal: bioRxiv
Article Title: Identification of MYC synthetic lethal genes and networks
doi: 10.1101/2024.04.25.590465
Figure Lengend Snippet: Further validation of a selection of MYC SL genes. A. MYC overexpression increases sensitivity to the MCL1 inhibitor S63845. HCEC cells with TRE-MYC were treated vehicle or 100 ng/mL doxycycline and with the indicated doses of S63845. After 72 h, cell viability was measured by CellTiter Blue and the GR50 was determined using the online GR calculator ( http://www.grcalculator.org/grcalculator/ ) which can correct for the proliferation rate difference in cells with low and high MYC expression. B. Treatment of MYC overexpressing cells with S63845 induces visual apoptosis. Cells were treated with 1 μM of S63845 for 72 h and images were taken. Cells treated with dox to induce high levels of MYC expression were noticeably more apoptotic (i.e. round cells that detached from the plate) than those not treated with dox. C. Treatment of MYC overexpressing cells with S63845 induces apoptosis as determined by western blot. HCEC cells with TRE-MYC were treated vehicle or 100 ng/mL doxycycline and either DMSO, 100 nM, or 1 μM S63845 for 24 h. Cell lysates were analyzed for cleaved caspase 3 and cleaved PARP to monitor apoptosis induction. D. CRISPR disruption of HSF1 expression. HSF1 targeting sgRNAs used in the MCA in were expressed in HCEC TRE-MYC cells. Following 1 week of sgRNA expression, HSF1 protein levels were determined by western blot. E. Inhibition of CHKA via MN58b is more toxic to MYC overexpressing cells. Non- fluorescent HCEC TRE-MYC cells were mixed with GFP+ HCECs at an 80:20 ratio. Cell mixtures were treated with the indicated concentrations of the CHKA inhibitor MN58b or DMSO vehicle control. Changes in cell populations were determined after 48 h of treatment by flow cytometry. F. CRISPR disruption of PPAT is toxic to MYC overexpressing cells. Non-fluorescent HCEC TRE-MYC cells were mixed with GFP+ HCECs at an 80:20 ratio. Cell mixtures were treated with the indicated sgRNAs. After 1 week in 100 ng/mL dox, cell populations were examined by flow cytometry. Numbers above bar graphs indicate the p-value from an unpaired Student’s t-test to compare sgRNA or treatment groups to sgControl or Vehicle, respectively.
Article Snippet: Membranes were blocked for 1 h at room temperature with 5% milk in TBST (Santa Cruz, cat. # sc-362311) and incubated with the following antibodies at the indicated dilutions in 5% BSA (VWR, cat. # VWRV0332) in TBST either overnight at 4C or 1 h at room temperature: Vinculin (1:10,000, Sigma cat. # V9131), MYC (1:1,000, Cell Signaling, cat. # 5605), CHKA (1:1,000, Cell Signaling, cat. # 13422), CS (1:1,000, ProteinTech, cat. # 16131-1-AP), SLC25A1 (1:1,000, ProteinTech, cat. # 5235-1-AP), PGD (1:1,000, ProteinTech, cat. # 14718-1-AP), ATF4 (1:1,000, Cell Signaling, cat. # 11815), CHOP (1:1,000, Cell Signaling, cat. # 2895), PARP (1:1,000, Cell Signaling, cat. # 9542), Caspase 3 (1:1,000, Cell Signaling, cat. # 9662), HSF1 (1:1,000, Cell Signaling, cat. # 4356), β-actin(1:10,000, Cell Signaling, cat. # 3700), and GAPDH (1:10,000, Santa Cruz, cat. # sc-365062).
Techniques: Biomarker Discovery, Selection, Over Expression, Expressing, Western Blot, CRISPR, Disruption, Inhibition, Control, Flow Cytometry