TY - JOUR
T1 - Combined inhibition of Rad51 and Wee1 enhances cell killing in HNSCC through induction of apoptosis associated with excessive DNA damage and replication stress
AU - Lindemann, Antje
AU - Patel, Ameeta A.
AU - Tang, Lin
AU - Tanaka, Noriaki
AU - Gleber-Netto, Frederico O.
AU - Bartels, Mason D.
AU - Wang, Li
AU - McGrail, Daniel J.
AU - Lin, Shiaw Yih
AU - Frank, Steven J.
AU - Frederick, Mitchell J.
AU - Myers, Jeffrey N.
AU - Osman, Abdullah A.
N1 - Funding Information:
S.J. Frank reports grants from Eli Lilly and Hitachi; personal fees from Boston Scientific, Varian, and personal fees from C4 Imaging outside the submitted work. No disclosures were reported by the other authors.
Publisher Copyright:
© 2021 American Association for Cancer Research.
PY - 2021/7
Y1 - 2021/7
N2 - Despite advances in surgery, chemotherapy, and radiation, there are limited treatment options for advanced head and neck squamous cell carcinoma (HNSCC) and survival remains very poor. Therefore, effective therapies are desperately needed. Recently, selective exploitation of DNA damage and replication stress responses has become a novel approach for cancer treatment. Wee1 kinase and Rad51 recombinase are two proteins involved in regulating replication stress and homologous recombination repair in cancer cells. In this study, we investigated the combined effect of Rad51 inhibitor (B02) and Wee1 inhibitor (AZD1775) in vitro and in vivo in various HNSCC cell lines. Clonogenic survival assays demonstrated that B02 synergized with AZD1775 in vitro in all HNSCC cell lines tested. The synergy between these drugs was associated with forced CDK1 activation and reduced Chk1 phosphorylation leading to induction of excessive DNA damage and replication stress, culminating in aberrant mitosis and apoptosis. Our results showed that elevated Rad51 mRNA expression correlated with worse survival in HNSCC patients with HPV-positive tumors. The combination of B02 and AZD1775 significantly inhibited tumor growth in vivo in mice bearing HPV-positive HNSCC tumors as compared to HPV-negative HNSCC. This differential sensitivity appears to be linked to HPV-positive tumors having more in vivo endogenous replication stress owing to transformation by E6 and E7 oncogenes. Furthermore, addition of B02 radiosensitized the HPV-negative HNSCC tumors in vitro and in vivo. In conclusion, our data implicate that a novel rational combination with Rad51 and Wee1 inhibitors holds promise as synthetic lethal therapy, particularly in high-risk HPV-positive HNSCC.
AB - Despite advances in surgery, chemotherapy, and radiation, there are limited treatment options for advanced head and neck squamous cell carcinoma (HNSCC) and survival remains very poor. Therefore, effective therapies are desperately needed. Recently, selective exploitation of DNA damage and replication stress responses has become a novel approach for cancer treatment. Wee1 kinase and Rad51 recombinase are two proteins involved in regulating replication stress and homologous recombination repair in cancer cells. In this study, we investigated the combined effect of Rad51 inhibitor (B02) and Wee1 inhibitor (AZD1775) in vitro and in vivo in various HNSCC cell lines. Clonogenic survival assays demonstrated that B02 synergized with AZD1775 in vitro in all HNSCC cell lines tested. The synergy between these drugs was associated with forced CDK1 activation and reduced Chk1 phosphorylation leading to induction of excessive DNA damage and replication stress, culminating in aberrant mitosis and apoptosis. Our results showed that elevated Rad51 mRNA expression correlated with worse survival in HNSCC patients with HPV-positive tumors. The combination of B02 and AZD1775 significantly inhibited tumor growth in vivo in mice bearing HPV-positive HNSCC tumors as compared to HPV-negative HNSCC. This differential sensitivity appears to be linked to HPV-positive tumors having more in vivo endogenous replication stress owing to transformation by E6 and E7 oncogenes. Furthermore, addition of B02 radiosensitized the HPV-negative HNSCC tumors in vitro and in vivo. In conclusion, our data implicate that a novel rational combination with Rad51 and Wee1 inhibitors holds promise as synthetic lethal therapy, particularly in high-risk HPV-positive HNSCC.
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U2 - 10.1158/1535-7163.MCT-20-0252
DO - 10.1158/1535-7163.MCT-20-0252
M3 - Article
C2 - 33947685
AN - SCOPUS:85107531827
SN - 1535-7163
VL - 20
SP - 1257
EP - 1269
JO - Molecular cancer therapeutics
JF - Molecular cancer therapeutics
IS - 7
ER -