Figure 1

Knockdown of cancer-derived IgG inhibited the growth and proliferation of cells in vitro and in vivo. HeLa cells were treated with IGHG1 siRNA or scrambled siRNA. IgGγ protein levels (a) and mRNA levels (b) were detected. (c) The viability of similarly treated cells was analyzed with cell proliferation assay. Results are presented as percentage of cells proliferation in comparison to the negative control. HEp-2 and PC3 cells were also treated with the same protocol (e, f, h). (d) HeLa cells treated with IGHG1 siRNA or scrambled siRNA were analyzed morphologically 3 days before and 3 days after the treatment. The images are shown in the left panel. Scale bar, 50 μm. The statistical analysis of cell number under the same conditions was performed and results showed in the right panel. Similar experiments were also performed in HeLa cells stably expressing IGHG1 shRNA or control shRNA (Supplementary Figures S3b–e). (g) Reduced tumor volumes in the bilateral groin of BALB/c nude mice injected with IGHG1 shRNA cells, compared with controls (control shRNA cells). Each data point is the mean value (±S.E.M.) of six tumors. Photographs of representative mice and tumors are shown, along with haematoxylin and eosin staining of tumor. Scale bar, 20 μm. Western blot and RT-qPCR confirmed tumor originated from injected IGHG1 shRNA cells or control shRNA cells. (i) Reduction of cancer-derived IgG induced cell cycle arrest. HeLa cells were treated with scrambled siRNA or IGHG1 siRNA for 72 h. The cell cycle progression was detected with flow cytometry. The percentage of cells in the S phase was calculated. The RT-qPCR, MTS, cell number and cell cycle data are expressed as mean±S.D. from three independent experiments (*P<0.05; **P<0.01)