Fig 2: RPL32 knockdown inhibits the migration and invasion of SUM 1315 cells. (A) Cell Counting Kit-8 assay indicated that 1315-KD cells had a similar proliferative ability compared with 1315-CON cells. (B) Wound-healing assay (magnification, ×100) demonstrated that RPL32-silenced cells (C) exhibited a delayed wound closure of scratch gaps, compared with the control cells. (D) Transwell assays revealed that (E) fewer 1315-KD cells than 1315-CON cells invaded the filter, with or without Matrigel. 1315-CON and SUM 1315 cells were stably transfected with negative control lentivirus. 1315-KD and SUM 1315 cells were stably transfected with RPL32 siRNA lentivirus. Scale bar, 200 µm. *P<0.05 vs. 1315-CON cells. RPL32, ribosomal protein L32; si, small interfering; CON, control; OD, optical density; KD, knockdown.

Fig 3: RPL32 knockdown suppresses SUM 1315 cell metastasis in vivo. (A) Images of the xenograft tumors were captured at the end of the experiment. (B) Results demonstrated that there was no significant difference in tumor size between the 1315-CON and 1315-KD groups. (C) Histological analysis identified more lung metastases in the 1315-CON compared with the 1315-KD group (magnification at ×100 and ×400). 1315-CON and SUM 1315 cells were stably transfected with negative control lentivirus. 1315-KD and SUM 1315 cells were stably transfected with RPL32 siRNA lentivirus. RPL32, ribosomal protein L32; si, small interfering; CON, control; KD, knockdown.

Fig 4: RPL32 is upregulated in BC tissues. (A) A pronounced immunohistochemical staining of RPL32 was detected in BC specimens compared with matched healthy tissues. (B) A higher mRNA expression of RPL32 was detected in BC compared with adjacent healthy breast tissues, as determined by RT-qPCR. (C) A higher mRNA expression of RPL32 was detected in BC cell lines compared with the normal breast epithelial cell line, as determined by RT-qPCR. *P<0.05 vs. breast cancer tissue or MCF-10A cells. RPL32, ribosomal protein L32; BC, breast cancer; RT-qPCR, reverse transcription-quantitative PCR.

Fig 5: Lentivirus-delivered siRNA silencing specifically inhibits the expression of RPL32 at the mRNA and protein levels. (A) Infection efficiency of the lentivirus was monitored by detecting GFP expression after 3 days of transduction (magnification, ×100). (B) Reverse transcription-quantitative PCR demonstrated that the RPL32 mRNA expression was significantly decreased in 1315-KD cells. (C) Western blot analysis identified that (D) RPL32 protein expression was significantly decreased in 1315-KD cells. 1315-CON and SUM 1315 cells were stably transfected with negative control lentivirus, while 1315-KD and SUM 1315 cells were stably transfected with RPL32 siRNA lentivirus. *P<0.05 vs. 1315-CON. si, small interfering; RPL32, ribosomal protein L32; GFP, green fluorescent protein; CON, control; KD, knockdown.