Targeting of β1 integrins impairs DNA repair for radiosensitization of head and neck cancer cells

Abstract

β1 Integrin-mediated cell-extracellular matrix interactions allow cancer cell survival and confer therapy resistance. It was shown that inhibition of β1 integrins sensitizes cells to radiotherapy. Here, we examined the impact of β1 integrin targeting on the repair of radiation-induced DNA double-strand breaks (DSBs). β1 Integrin inhibition was accomplished using the monoclonal antibody AIIB2 and experiments were performed in three-dimensional cell cultures and tumor xenografts of human head and neck squamous cell carcinoma (HNSCC) cell lines. AIIB2, X-ray irradiation, small interfering RNA-mediated knockdown and Olaparib treatment were performed and residual DSB number, protein and gene expression, non-homologous end joining (NHEJ) activity as well as clonogenic survival were determined. β1 Integrin targeting impaired repair of radiogenic DSB (γH2AX/53BP1, pDNA-PKcs T2609 foci) in vitro and in vivo and reduced the protein expression of Ku70, Rad50 and Nbs1. Further, we identified Ku70, Ku80 and DNA-PKcs but not poly(ADP-ribose) polymerase (PARP)-1 to reside in the β1 integrin pathway. Intriguingly, combined inhibition of β1 integrin and PARP using Olaparib was significantly more effective than either treatment alone in non-irradiated and irradiated HNSCC cells. Here, we support β1 integrins as potential cancer targets and highlight a regulatory role for β1 integrins in the repair of radiogenic DNA damage via classical NHEJ. Further, the data suggest combined targeting of β1 integrin and PARP as promising approach for radiosensitization of HNSCC.

Collective cancer invasion forms an integrin-dependent radioresistant niche

“…Additional noncanonical effectors of integrin signaling further include cross-talk with the CD44/hyaluronic acid axis, epidermal growth factor (EGF) receptor, and syndecan signaling (Yu et al, 2000;Ghatak et al, 2014;McQuade et al, 2006). In head and neck squamous cell carcinoma cells, β1 integrin activating FAK/JNK1 is essential for the repair of radiation-induced DSBs, and β1 integrin signaling supports expression of essential DNA repair genes, including Ku70/80 and Rad51 (Dickreuter et al, 2016;Ahmed et al, 2018). These data link integrin signaling to Treatment schemes for HT-1080 and MV3 tumors.…”

Targeting Lung Cancer Stem Cells: Research and Clinical Impacts

“…In consistent with this study, study on breast cancer showed that after treatment of cancer cell with taxol, the integrin α6 + CSC population is upregulated (111). Also, study of β1 integrins on head and neck cancer cell also support that integrins can act as potential cancer targets (112). However, specific integrins that is responsible to promote stemness, drug resistance, and metastasis of CSCs are yet to be determined (113).…”

RGD-Binding Integrins in Head and Neck Cancers

“…Moreover, targeting β1 integrin with an inhibitory antibody increased sensitivity to ionizing radiation and delayed the growth of HNSCC cell lines in 3D cultures and in xenografted mice [101], and has been shown to act by impairing repair of radiation-induced DNA double-strand breaks [102,103]. Combining the anti-β1 monoclonal antibody AIIB2 with a poly ADP ribose polymerase (PARP) inhibitor [102] or EGFR inhibitor [103] enhanced cytotoxicity and radiosensitization, providing better in vivo tumour control compared with monotherapy and irradiation in HNSCC models [103]. The combination of β1 and EGFR inhibition is proposed to act by preventing activation of MEK/ERK signalling, bypassing the effect of a single inhibitor [103].…”

“…With the exception of cilengitide, very limited preclinical studies have taken place so far [80,88,107]. The observations that inhibiting αv [55], αvβ3 [74], or β1 [101,102,103] increases sensitivity to irradiation is particularly significant for HNSCC as it suggests integrin-targeted therapy could be used as part of a chemoradiotherapy strategy for high risk disease.…”