ABT-263 Reduces Hypertrophic Scars by Targeting Apoptosis of Myofibroblasts

Abstract

Background: Inhibiting proliferation and inducing apoptosis of myofibroblasts is becoming one of the promising and effective ways to treat hypertrophic scar. ABT-263, as an orally bioavailable BCL-2 family inhibitor, has showed great anti-tumor characteristics by targeting tumor cells apoptosis. The objective of this study was to explore the potential therapeutical effects of ABT-263 on hypertrophic scar formation in vivo and in vitro. Methods: In vivo, we used ABT-263 to treat scars in a rabbit ear scar model. Photographs and ultrasound examination were taken weekly, and scars were harvested on day 42 for further Masson trichrome staining. In vitro, the expression levels of BCL-2 family members, including pro-survival proteins, activators and effectors, were detected systematically in human hypertrophic scar fibroblasts (HSFs) and human normal dermal fibroblasts (HFBs). The roles of ABT-263 in apoptosis and proliferation of HSFs and HFBs were determined by Annexin V/PI assay, CCK-8 kit and cell cycle analysis. Mitochondrial membrane potential was evaluated by JC-1 staining and the expression of type I/III collagen and α-SMA were measured by PCR, western blotting and immunofluorescence staining. Furthermore, immunoprecipitation was performed to explore the potential mechanism. Findings: In vivo, ABT-263 could significantly improve the scar appearance and collagen arrangement, and decrease scar elevation index (SEI). In vitro, the expression levels of BCL-2, BCL-XL and BIM were significantly higher in HSFs than that in HFBs. ABT-263 selectively induced HSFs apoptosis by releasing BIM from binding with pro-survival proteins. Moreover, ABT-263 inhibited HSFs proliferation and reduced the expression of α-SMA and type I/III collagen in a concentration- and time- dependent manner. Interpretation: HSFs showed increased mitochondrial priming with higher level of pro-apoptotic activator BIM and were primed to death. ABT-263 showed great therapeutic ability in the treatment of hypertrophic scar by targeting HSFs. Funding Statement: This work was supported by National Key RD Youth Incubation Plan of the Military Medical Science and Technology (20QNPY035)；the National Nature Science Foundation of China (81701905, 81772076, 81871559, 81571897); and Shanghai health system excellent talent training program (2017BR037). Declaration of Interests: The authors declare no competing interests with relevance to this study. Ethics Approval Statement: All experimental procedures have been approved by the Ethics Committee of Changhai Hospital, Shanghai, China. Informed consent was obtained. All animal studies were approved by the Animal Center of the Naval Military Medical University, Shanghai, China.