Down-regulation of RAC2 by small interfering RNA restrains the progression of osteosarcoma by suppressing the Wnt signaling pathway
Authors: Qi Chen
Fang Li
Changyan Wu
Yifu Sun
Wei Zhang
Liwei Shao
Peng Xia
Xu Gao
Journal: International Journal of Biological Macromolecules (2019)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: Gene silencing; Invasion; Osteosarcoma; Proliferation; RAC2
Affiliations: Department of Orthopaedics, Second Hospital of Jilin University, Changchun 130041, PR China., Department of Orthopaedics, China-Japan Union Hospital of Jilin University, Changchun 130033, PR China., Department of Orthopaedics, China-Japan Union Hospital of Jilin University, Changchun 130033, PR China. Electronic address: .

Abstract:  Osteosarcoma (OS) is the most common primary malignancy of bone and is characterized by a high malignant and metastatic potential. Microarray-based differentially expressed gene screening determined RAC2 as the candidate gene related to OS. Highly expressed RAC2 and activated Wnt signaling pathway were determined in OS tissues using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. The OS cells were transfected with siRNA-RAC2 or treated with BIO (activator of Wnt pathway), whereby the effects of siRNA-RAC2 on cell proliferation, invasion, cycle and apoptosis were analyzed by CCK-8, Transwell assay and flow cytometry. The mRNA and protein levels of RAC2 and the Wnt signaling pathway-, proliferation- and apoptosis-related genes in OS cells were determined by RT-qPCR and Western blot assay. Importantly, siRNA-mediated RAC2 silencing inhibited the activation of the Wnt signaling pathway in OS. siRNA-RAC2 inhibited the proliferation and invasion, while impeded OS cell cycle progression and facilitated cell apoptosis. However, activation of Wnt signaling pathway reversed the effects of siRNA-RAC2. Finally, orthotopic xenograft OS mouse model confirmed the in vivo anti-tumor effects by silencing RAC2. Taken together, RAC2 gene silencing could suppress OS progression. The mechanism was obtained by inhibiting the activation of the Wnt signaling pathway. 

Retracted: No

PubPeer comments:
 Fig 4B,  invasion conditions in OS cells transfected with siRNA-RAC2 and treated with Wnt signaling pathway activator, BIO, or either alone observed under a microscope .  I have rotated one panel through 90 deg for better comparison with a panel of Fig 6A from [Zou, Zhang Li (2017)] .  Invasion abilities of MG-63 cells among the blank, scrambled control, and SOST-siRNA groups. Notes A the micrographs of MG-63 cells with crystal violet staining in transwell assay .  , 
 #1  Blue and yellow rectangles mark overlaps with panels of Fig 11a from [Song, Wang Huo (2019)] .  See also Fig 7A from [Wang et al (2017)] .  The reuse and modification of these images could be traced further through this oeuvre, but I do not want to be tiresome. , 
 Fig 5A. I am curious about the equipment used to plot these free-form, overhanging flow-cytometry plots.  , 
 #1 Thank you for your attention. Our group have taking serious attention to your challenge. We have all the original photografts in hand, including that crystal vialet, which is likely or similar to a previous paper. we can provide other sights for that dish of cell, we will contact the editor if requested. The cytometer we use was Easycyte system (EMD Millipore Corp.) , 
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