A Small Molecule Inhibitor Selectively Induces Apoptosis in Cells Transformed by High Risk Human Papilloma Viruses.
A phenotypic high-throughput cell culture screen was performed to identify compounds that prevented proliferation of the human Papilloma virus type 16 (HPV-16) transformed cell line Ca Ski. A series of quinoxaline compounds exemplified by Compound 1 was identified. Testing against a panel of cell lines demonstrated that Compound 1 selectively inhibited replication of all HPV-16, HPV-18, and HPV-31 transformed cell lines tested with 50% Inhibitory Concentration (IC50) values of 2 to 8 μM relative to IC50 values of 28 to 73 μM in HPV-negative cell lines. Treatment with Compound 1 resulted in a cascade of multiple apoptotic events, including selective activation of effector caspases 3 and 7, fragmentation of cellular DNA, and PARP (poly(ADP-ribose) polymerase) cleavage in HPV-positive cells relative to HPV-negative cells. Unregulated proliferation of HPV transformed cells is dependent on the viral oncogenes, E6 and E7. Treatment with Compound 1 resulted in a decrease in HPV E7 protein in Ca Ski cells. However, the timing of this reduction relative to other effects of compound treatment suggests that this was a consequence, rather than a cause, of the apoptotic cascade. Likewise, compound treatment resulted in no obvious effects on the E6- and E7- mediated down regulation of p53 and Rb, or their downstream effectors, p21 or PCNA. Further investigation of apoptotic signals induced by Compound 1 revealed cleavage of Caspase-8 in HPV-positive cells as early as 2 hours post-treatment, suggesting the compound initiates apoptosis through the extrinsic, death receptor-mediated, pathway of cell death. These studies provide proof of concept that cells transformed by oncogenic Papillomaviruses can be selectively induced to undergo apoptosis by compound treatment.
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Amy K
http://orcid.org/0000-0002-4776-4679
AK
Sheaffer
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Min S
MS
Lee
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Huilin
H
Qi
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Susan
S
Chaniewski
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Xiaofan
X
Zheng
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Glen A
GA
Farr
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Kim
K
Esposito
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
David
D
Harden
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Ming
M
Lei
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Liang
L
Schweizer
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Jacques
J
Friborg
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Michele
M
Agler
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Fiona
F
McPhee
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Robert
R
Gentles
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Brett R
BR
Beno
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Lou
L
Chupak
Bristol-Myers Squibb, Research and Development, Wallingford, CT, United States of America.
Stephen
S
Mason
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D002472:Cell Transformation, Viral / Q000187:drug effects*; D005260:Female; D006801:Humans; D027383:Papillomaviridae / Q000187:drug effects*; D050725:Papillomavirus E7 Proteins / Q000378:metabolism; D030361:Papillomavirus Infections / Q000188:drug therapy / Q000473:pathology* / Q000821:virology; D016160:Retinoblastoma Protein / Q000378:metabolism; D054852:Small Molecule Libraries / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000821:virology
D051017:Apoptosis Regulatory Proteins; D050725:Papillomavirus E7 Proteins; D016160:Retinoblastoma Protein; D054852:Small Molecule Libraries; D016159:Tumor Suppressor Protein p53