Mesenchymal Stem Cell-Based NK4 Gene Therapy in Nude Mice Bearing Gastric Cancer Xenografts [Corrigendum]

Zhu Y, Cheng M, Yang Z, et al. Drug Des Devel Ther. 2014;8:2449–2462. The authors have advised that figure parts 2E and 4B on pages 2454 and 2456, respectively, are incorrect. An error at the time of figure assembly led to the inadvertent duplication of images in both figures. The correct Figure 2 and 4 are shown below. Figure 2 Continued. Figure 2 Transduction of NK4 cDNA into human MSCs using a lentiviral vector and characterization.Abbreviations: GFP, green fluorescent protein; conc, concentration; HGF, hepatocyte growth factor; ANOVA, analysis of variance; rhHGF, recombinant human hepatocyte growth factor; MOI, multiplicity of infection; Mr, molecular weight; MSCs, mesenchymal stem cells; cDNA, complementary DNA.Notes: The recombinant pGC-FU-GFP-NK4-plasmids, the construction plasmids Helper1.0, and the envelope plasmids Helper2.0 (GeneChem Co., Ltd., Shanghai, People’s Republic of China) were first cotransfected into 293T cells. MSCs were then transduced with Lenti-NK4 (MSCs-NK4) or Lenti-GFP (MSCs-GFP) at varying multiplicity of infection (MOI). (A) Expression of GFP in MSCs observed at day three after Lenti-NK4 infection at MOI of 10, 20, 50, or 100 under fluorescence microscopy, (B) transduction efficiency of Lenti-NK4 in MSCs determined by flow cytometry with an GFP marker which was 87.8% of the enriched GFP-expressing MSC population upon sorting with an MOI of 50, (C) effect of transduction with Lenti-NK4 at different MOIs from 1 to 100 in MSCs on the production of NK4 in the culture medium, (D) effect of time on the production of NK4 in the culture medium after MSCs were transduced with Lenti-NK4 (MOI =50), Lenti-GFP (MOI =50), or not transduced, (E) MSCs-NK4 with increased GFP expression observed at different time points (MOI =50, from Day 1 to Day 3), and (F) Western blot analysis of NK4-GFP fusion protein with a molecular weight of 84 kDa. Recombinant human HGF (Mr =83 kDa) was used as a positive control. *P<0.05; ***P<0.001 MSCs-NK5 versus control groups, by one- or two-way ANOVA. Figure 4 Continued. Figure 4 Effects of MKN45 or GES-1 cell-conditioned medium on the migratory ability of MSCs and MSCs-NK4 toward gastric cancer cells determined using a Transwell migration assay.Abbreviations: MSCs, mesenchymal stem cells; ANOVA, analysis of variance.Notes: MNK45 or GES-1 cells were cultured for 24 hours in serum-free medium and then plated onto the bottom wells. MSCs, MSCs-NK4, or human fibroblasts cultured in serum-free medium were seeded onto the upper chamber and cultured for 24 hours. The MSCs, MSCs-NK4, or human fibroblasts that attached to the top side of the membrane were removed, and the cells that migrated onto the bottom side were fixed, stained, and counted (five fields per well) at 10× magnification using a microscope. (A) MKN45 cell-conditioned medium significantly stimulated the directional migration of MSCs and MSCs-NK4 compared to human fibroblasts. MSCs and MSCs-NK4 significantly migrated to MKN45 cell-conditioned medium, whereas GES-1 cell-conditioned medium or unconditioned medium did not promote the directional migration of MSCs or MSCs-NK4. ***P<0.001, by two-way ANOVA. (B) Representative photomicrographs of stained filters showing migrated MSCs and MSCs-NK4 when MKN45 or GES-1 cells were cultured at the bottom side of the well. Transwell migration assay from Corning Incorporated, Corning, NY, USA. The authors apologize for these errors and advise they do not affect the results of the paper.