Abstract
Background : While anti-HER2 tyrosine kinase inhibitors (TKIs) have radically prolonged survival and improved prognosis in HER2-positive breast cancer patients, resistance to these therapies is a constant obstacle leading to TKIs treatment failure and tumor progression.Methods : To develop new strategies to enhance TKIs efficiency by combining synergistic gene targets, we performed panel library screening using CRISPR/Cas9 knockout technique based on data mining across TCGA datasets and verified the candidate target in pre-clinical models and breast cancer high-throughput sequencing datasets.Results : We identified that CDK12, co-amplified with HER2 in a high frequency, is powerful to sensitize or re-sensitize HER2-positive breast cancer to anti-HER2 TKIs lapatinib, evidenced by patient-derived organoids (PDO) in vitro and cell-derived xenograft (CDX) or patient-derived xenograft (PDX) in vivo. Exploring mechanisms, we found that inhibition of CDK12 attenuated PI3K/AKT signal, which usually serves as an oncogenic driver and is reactivated when HER2-positive breast cancers develop resistance to lapatinib. Combining CDK12 inhibition exerted additional suppression on p-AKT activation induced by anti-HER2 TKIs lapatinib treatment. Clinically, via DNA sequencing data for tumor tissue and peripheral blood ctDNA, we found that HER2-positive breast cancer patients with CDK12 amplification responded more insensitively to anti-HER2 treatment than those without accompanying CDK12 amplification by harboring a markedly shortened progression free survival (PFS) (median PFS: 4.3 months verse 6.9 months; HR 2.26 [95% CI 1.32-3.86]; P=0.0028).Conclusions : Dual inhibition of HER2/CDK12 will prominently benefit the outcomes of HER2-positive breast cancer patients by sensitizing or re-sensitizing the tumors to anti-HER2 TKIs treatment.
High-throughput sequencing of two populations of extracellular vesicles provides an mRNA signature that can be detected in the circulation of breast cancer patients