TY - JOUR
T1 - Small-molecule natural product physachenolide C potentiates immunotherapy efficacy by targeting BET proteins
AU - Tewary, Poonam
AU - Brooks, Alan D.
AU - Xu, Ya Ming
AU - Kithsiri Wijeratne, E. M.
AU - Babyak, Ashley L.
AU - Back, Timothy C.
AU - Chari, Raj
AU - Evans, Christine N.
AU - Henrich, Curtis J.
AU - Meyer, Thomas J.
AU - Edmondson, Elijah F.
AU - De Aquino, Maria T.Prudente
AU - Kanagasabai, Thanigaivelan
AU - Shanker, Anil
AU - Leslie Gunatilaka, A. A.
AU - Sayers, Thomas J.
N1 - Publisher Copyright:
© 2021 American Association for Cancer Research.
PY - 2021/6
Y1 - 2021/6
N2 - Screening for sensitizers of cancer cells to TRAIL-mediated apoptosis identified a natural product of the 17β-hydroxywithanolide (17-BHW) class, physachenolide C (PCC), as a promising hit. In this study, we show that PCC was also able to sensitize melanoma and renal carcinoma cells to apoptosis in response not only to TRAIL, but also to the synthetic polynucleotide poly I:C, a viral mimetic and immune activator, by reducing levels of antiapoptotic proteins cFLIP and Livin. Both death receptor and TLR3 signaling elicited subsequent increased assembly of a proapoptotic ripoptosome signaling complex. Administration of a combination of PCC and poly I:C in human M14 melanoma xenograft and a syngeneic B16 melanoma model provided significant therapeutic benefit as compared with individual agents. In addition, PCC enhanced melanoma cell death in response to activated human T cells in vitro and in vivo in a death ligand-dependent manner. Biochemical mechanism-ofaction studies established bromo and extraterminal domain (BET) proteins as major cellular targets of PCC. Thus, by targeting of BET proteins to reduce antiapoptotic proteins and enhance caspase-8-dependent apoptosis of cancer cells, PCC represents a unique agent that can potentially be used in combination with various immunotherapeutic approaches to promote tumor regression and improve outcome.
AB - Screening for sensitizers of cancer cells to TRAIL-mediated apoptosis identified a natural product of the 17β-hydroxywithanolide (17-BHW) class, physachenolide C (PCC), as a promising hit. In this study, we show that PCC was also able to sensitize melanoma and renal carcinoma cells to apoptosis in response not only to TRAIL, but also to the synthetic polynucleotide poly I:C, a viral mimetic and immune activator, by reducing levels of antiapoptotic proteins cFLIP and Livin. Both death receptor and TLR3 signaling elicited subsequent increased assembly of a proapoptotic ripoptosome signaling complex. Administration of a combination of PCC and poly I:C in human M14 melanoma xenograft and a syngeneic B16 melanoma model provided significant therapeutic benefit as compared with individual agents. In addition, PCC enhanced melanoma cell death in response to activated human T cells in vitro and in vivo in a death ligand-dependent manner. Biochemical mechanism-ofaction studies established bromo and extraterminal domain (BET) proteins as major cellular targets of PCC. Thus, by targeting of BET proteins to reduce antiapoptotic proteins and enhance caspase-8-dependent apoptosis of cancer cells, PCC represents a unique agent that can potentially be used in combination with various immunotherapeutic approaches to promote tumor regression and improve outcome.
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U2 - 10.1158/0008-5472.CAN-20-2634
DO - 10.1158/0008-5472.CAN-20-2634
M3 - Article
C2 - 33837043
AN - SCOPUS:85108080992
SN - 0008-5472
VL - 81
SP - 3374
EP - 3386
JO - Cancer Research
JF - Cancer Research
IS - 12
ER -