The cytoskeleton is a central factor providing numerous hallmarks of cancer. Actin regulatory proteins are involved in breast malignancy, and their dysregulation was shown to predict poor clinical prognosis. Twinifilin1 (TWF1), an actin dynamic regulator, has been identified as an oncoprotein in breast cancer (BC), as it promotes the proliferation of MCF-7 cells (luminal A cell line). TWF1 role in Triple-negative Breast Cancer (TNBC) is not fully comprehended. This study aimed to assess the role of actin dynamic regulators TWF1, destrin (DSTN) and the effect of their knockdown by mir-320a mimic in TNBC cell lines. TNBC cells were transfected with either a Negative Control (NC) or a miR-320a mimic. Cell proliferation was evaluated using a colony forming assay. Reverse transcription-quantitative PCR was used to determine the expression levels of TWF1 and DSTN mRNA. Cell proliferation in TNBC cells decreased after transfection with miR-320a. DSTN expression was significantly impaired upon transfection with miR-320a in TNBC cells, whereas the level of TWF1 expression did not change. Collectively, these observations suggested that miR-320a may inhibit DSTN expression, which, in turn, could contribute to tumorigenesis. Meanwhile, the TWF1 expression level indicated that the interactions between miRNAs and their targets aren't always one-to-one, and the functions of miRNAs are interactive and complex.