The authors wish to make the following correction to this paper []. The authors state that the scientific conclusions remain unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.
- Error in Figures
In the original publication, there was a mistake in Figure 1B,C, and Figure 2 (DOX(−) MSC-Tet-TK) as published. The error occurred due to erroneous copying of images during figure assembly. The corrected version of Figure 1B,C, and Figure 2 (DOX(−) MSC-Tet-TK) appears below.
- Figure 1B
- Figure 1C
- Figure 2. (DOX(−) MSC-Tet-TK).
- Error in Figure Legends
In the original publication, there were typographical errors in the legends for Figures 2 and 3. The correct legends appear below.
- Figure 2. Fluc activity of MSC-Tet-TK and MSC-TK cells after ganciclovir (GCV) treatment for 48 h. Fluc activity was measured by bioluminescent imaging (BLI), and the quantitation for MSC-Tet-TK and MSC-TK cells is shown in the right-hand panel. Values obtained from three experiments are expressed as the mean ± standard deviation (SD), ** p < 0.01, *** p < 0.001 (by Student’s t-test). p/s, photons/second.
- Figure 3. Bystander effect of MSC-Tet-TK and MSC-TK cells. (A) Rluc activity in co-cultures (1:1) of naive MSCs and CT26/Rluc cells treated with the indicated concentrations of GCV for 48 h. (B) BLI images of the Rluc activity and quantitation data of CT26/Rluc in co-cultures (1:1) of MSC-TK or MSC-Tet-TK cells in the absence or presence of doxycycline (DOX(−) and DOX 2 μg/mL, respectively). Three experiments are expressed as the mean ± standard deviation (SD), * p < 0.05, ** p < 0.01, *** p < 0.001 (by Student’s t-test). p/s, photons/second.
- Text Correction
There was an error in the original publication []: an error in the figure results. A correction has been made to the Results Section, in the subsection “Characterization of MSC-Tet-TK and MSC-TK”, Paragraph Number 1:
- 2.1. Characterization of MSC-Tet-TK and MSC-TK
The transduced MSC-Tet-TK and MSC-TK cells were created by retroviral transfection, and eGFP-positive cells were sorted by FACS Aria III. Cells with an eGFP concentration of more than 50% were used for further study. The expression of MSC-TK cell eGFP and MSC-Tet-TK cell eGFP after induction with DOX (2 µg/mL) for 24 h (Figure 1A) was confirmed by confocal microscopy images. The morphology of MSC-Tet-TK cells are heterogeneous and not uniform, because MSCs are a heterogeneous cell population. MSC-Tet-TK cells with eGFP positive revealed more rod-like morphology than others, which might be related to the genetic alteration. Some of the MSC-TK cells revealed higher eGFP signals due to higher eGFP expression, because protein synthesis can vary with individual cells, withdifferent copy numbers of the transduced gene. The Fluc activity of MSC-TK cells increased with increasing cell numbers (Figure 1B, R2 = 0.90). The BLI signal in MSC-Tet-TK cells increased 15-, 21-, 25-, and 29-fold with increasing concentrations of DOX (0.25, 0.5, 1, and 2 µg/mL), whereas no signal was observed in DOX(−) cells (Figure 1C). Furthermore, we found that Fluc activity increased 17-, 19-, 20-, 20-, 15-, and 7-fold with increasing DOX treatment (0.5 to 4 µg/mL) for 48 h and then decreased at 8 and 16 µg/mL DOX (Figure S1). Therefore, in this study, we elected to use 2 µg/mL DOX for transgene activation.
Reference
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