Co-treatment with vactosertib, a novel, orally bioavailable activin receptor-like kinase 5 inhibitor, suppresses radiotherapy-induced epithelial-to-mesenchymal transition, cancer cell stemness, and lung metastasis of breast cancer

Abstract

Background Acquired metastasis and invasion of cancer cells during radiotherapy are in part due to induction of epithelial-to-mesenchymal transition (EMT) and cancer stem cell (CSC) properties, which are mediated by TGF-β signaling. Here we evaluated the anti-metastatic therapeutic potential of vactosertib, an orally bioavailable TGF-β type I receptor (activin receptor-like kinase 5, ALK5) inhibitor, via suppression of radiation-induced EMT and CSC properties, oxidative stress generation, and breast to lung metastasis in a breast cancer mouse model and breast cancer cell lines. Materials and methods Co-treatment of vactosertib with radiation was investigated in the 4T1-Luc allografted BALB/c syngeneic mouse model and in 4T1-Luc and MDA-MB-231 cells. The anti-metastatic therapeutic potential of vactosertib in breast cancer was investigated using fluorescence immunohistochemistry, real-time quantitative reverse transcription-polymerase chain reaction, western blotting, wound healing assay, mammosphere formation assay, and lung metastasis analysis in vitro and in vivo. Results Radiation induced TGF-β signaling, EMT markers (Vimentin, Fibronectin, Snail, Slug, Twist, and N-cadherin), CSC properties (expression of pluripotent stem cell regulators, mammosphere forming ability), reactive oxygen species markers (NOX4, 4-HNE), and motility of breast cancer cells in vitro and in vivo. Vactosertib attenuated the radiation-induced EMT and CSC properties by inhibiting ROS stress in breast cancer. Moreover, vactosertib combined with radiation showed a significant anti-metastatic effect with suppression of breast to lung metastasis in vivo. Conclusions These results indicate that inhibition of TGF-β signaling with vactosertib in breast cancer patients undergoing radiotherapy would be an attractive strategy for the prevention of cancer metastasis and recurrence.

TGF-beta signal transduction: biology, function and therapy for diseases

“…Vactosertib inhibits hepatic, renal, and pulmonary fibrosis by blocking both TGF-β1/SMAD2/3 and reactive oxygen species (ROS) signals [268]. The combination of vactosertib with radiation has a favorable antimetastatic efficacy in breast cancer [269]. Vactosertib prevents ulcerative colitis-associated inflammation and fibrosis, protecting against postsurgical adhesion formation by downregulating proinflammatory and profibrotic genes, inhibiting oxidative stress, decreasing inflammatory cell infiltration, and inhibiting excessive collagen deposition [270][271][272].…”

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

“…Additionally, clinical data showed lower protein expression levels of p-Smad2 in peripheral blood mononuclear cells of patients receiving the clinically beneficial Galunisertib [ 79 , 80 ]. Vactosertib is also a novel TβR1 inhibitor, currently under development in clinical trials, that inhibits the phosphorylation of Smad2 and Smad3 proteins, thereby suppressing EMT in tumor cells, and has been shown to be safe and well tolerated in phase I clinical studies [ 80 , 81 , 82 ]. In addition, Gefitinib (an EGFR-tyrosine kinase inhibitor) is among the anti-tumor drugs involved in the inhibition of the EMT process in tumor cells, with good results in clinical studies so far [ 83 , 84 ].…”

Radiotherapy-induced oxidative stress and fibrosis in breast cancer are suppressed by vactosertib, a novel, orally bioavailable TGF-β/ALK5 inhibitor

“…1 b). A radiation dose of 4 Gy × 3 reduced tumor volume in mice, and a dose of 2.5 mg/kg of vactosertib did not show organ toxicity to mice 19 . The protein level of p-SMAD2/3 was increased in the irradiated primary tumor but was decreased by combination treatment with vactosertib and radiation (Fig.…”

“…ROS is a mediator of radiation-induced EMT, and EMT is also known to play an important role in the acquisition of stem cell competence in cancer cells 31 . In a previous study, we reported that radiation increased EMT markers such as Snail, Twist, and N-cadherin and that vactosertib inhibited them 19 . Based on these results, we demonstrated that the increase in pluripotent stem cell modulators induced by radiation or GOX in breast cancer cells was inhibited by vactosertib.…”

“…TGF-β is one of www.nature.com/scientificreports/ the major signaling pathways contributing to these events activated by radiation 7,31,34 . Therefore, inhibition of TGF-β signaling induced by radiotherapy has been suggested as a therapeutic target for reducing side effects of radiotherapy 19 . We reported in this study that radiation-induced TGF-β could induce fibrosis and cancer stem cell properties through ROS and that combination therapy with the TGF-β/ALK5 inhibitor vactosertib could block this series of processes (Fig.…”