TY - JOUR
T1 - PI3K oncogenic mutations mediate resistance to afatinib in HER2/neu overexpressing gynecological cancers
AU - Bonazzoli, Elena
AU - Cocco, Emiliano
AU - Lopez, Salvatore
AU - Bellone, Stefania
AU - Zammataro, Luca
AU - Bianchi, Anna
AU - Manzano, Aranzazu
AU - Yadav, Ghanshyam
AU - Manara, Paola
AU - Perrone, Emanuele
AU - Haines, Kaitlin
AU - Espinal, Mariana
AU - Dugan, Katherine
AU - Menderes, Gulden
AU - Altwerger, Gary
AU - Han, Chanhee
AU - Zeybek, Burak
AU - Litkouhi, Babak
AU - Ratner, Elena
AU - Silasi, Dan Arin
AU - Huang, Gloria S.
AU - Azodi, Masoud
AU - Schwartz, Peter E.
AU - Santin, Alessandro D.
N1 - Publisher Copyright:
© 2019
PY - 2019/4
Y1 - 2019/4
N2 - Objective: Aberrant expression of HER2/neu and PIK3CA gene products secondary to amplification/mutations are common in high-grade-serous-endometrial (USC) and ovarian-cancers (HGSOC). Because scant information is currently available in the literature on the potential negative effect of PIK3CA mutations on the activity of afatinib, in this study we evaluate for the first time the role of oncogenic PIK3CA mutations as a potential mechanism of resistance to afatinib in HGSOC and USC overexpressing HER2/neu. Methods: We used six whole-exome-sequenced primary HGSOC/USC cell-lines and three xenografts overexpressing HER2/neu and harboring mutated or wild-type PIK3CA/PIK3R1 genes to evaluate the role of PI3K-mutations as potential mechanism of resistance to afatinib, an FDA-approved pan-c-erb-inhibitor in clinical trials in USC. Primary-USC harboring wild-type-PIK3CA gene was transfected with plasmids encoding oncogenic PIK3CA-mutations (H1047R/E545K). The effect of afatinib on HER2/PI3K/AKT/mTOR pathway was evaluated by immunoblotting. Results: We found PI3K wild-type cell-lines to be significantly more sensitive (lower IC50) than PI3K-mutated cell-lines p = 0.004). In vivo, xenografts of primary cell-line USC-ARK2, transfected with the PIK3CA-H1047R or E545K hotspot-mutations, exhibited significantly more rapid tumor growth when treated with afatinib, compared to mice harboring ARK2-tumors transfected with wild-type-PIK3CA (p = 0.041 and 0.001, respectively). By western-blot, afatinib effectively reduced total and phospho-HER2 proteins in all cell-lines. However, H1047R/E545K-PIK3CA-transfected-ARK2-cells demonstrated a greater compensatory increase in phosphorylated-AKT proteins after afatinib exposure when compared to controls ARK2. Conclusions: Oncogenic PI3K mutations may represent a major mechanism of resistance to afatinib. Combinations of c-erb with PIK3CA, AKT or mTOR inhibitors may be necessary to more efficiently block the PIK3CA/AKT/mTOR pathway.
AB - Objective: Aberrant expression of HER2/neu and PIK3CA gene products secondary to amplification/mutations are common in high-grade-serous-endometrial (USC) and ovarian-cancers (HGSOC). Because scant information is currently available in the literature on the potential negative effect of PIK3CA mutations on the activity of afatinib, in this study we evaluate for the first time the role of oncogenic PIK3CA mutations as a potential mechanism of resistance to afatinib in HGSOC and USC overexpressing HER2/neu. Methods: We used six whole-exome-sequenced primary HGSOC/USC cell-lines and three xenografts overexpressing HER2/neu and harboring mutated or wild-type PIK3CA/PIK3R1 genes to evaluate the role of PI3K-mutations as potential mechanism of resistance to afatinib, an FDA-approved pan-c-erb-inhibitor in clinical trials in USC. Primary-USC harboring wild-type-PIK3CA gene was transfected with plasmids encoding oncogenic PIK3CA-mutations (H1047R/E545K). The effect of afatinib on HER2/PI3K/AKT/mTOR pathway was evaluated by immunoblotting. Results: We found PI3K wild-type cell-lines to be significantly more sensitive (lower IC50) than PI3K-mutated cell-lines p = 0.004). In vivo, xenografts of primary cell-line USC-ARK2, transfected with the PIK3CA-H1047R or E545K hotspot-mutations, exhibited significantly more rapid tumor growth when treated with afatinib, compared to mice harboring ARK2-tumors transfected with wild-type-PIK3CA (p = 0.041 and 0.001, respectively). By western-blot, afatinib effectively reduced total and phospho-HER2 proteins in all cell-lines. However, H1047R/E545K-PIK3CA-transfected-ARK2-cells demonstrated a greater compensatory increase in phosphorylated-AKT proteins after afatinib exposure when compared to controls ARK2. Conclusions: Oncogenic PI3K mutations may represent a major mechanism of resistance to afatinib. Combinations of c-erb with PIK3CA, AKT or mTOR inhibitors may be necessary to more efficiently block the PIK3CA/AKT/mTOR pathway.
KW - Afatinib
KW - Gynecological cancer
KW - HER2/neu overexpression
KW - Mechanism of resistance
KW - PI3K mutation
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U2 - 10.1016/j.ygyno.2019.01.002
DO - 10.1016/j.ygyno.2019.01.002
M3 - Article
C2 - 30630630
AN - SCOPUS:85059539478
SN - 0090-8258
VL - 153
SP - 158
EP - 164
JO - Gynecologic oncology
JF - Gynecologic oncology
IS - 1
ER -