BCL7B, a SWI/SNF complex subunit, orchestrates cancer immunity and stemness

Abstract Cancer is one of the main causes of human death. Here, we focus on the B-cell lymphoma 7 protein family member B (BCL7B) gene, an accessory subunit of the SWI/SNF chromatin-remodelling complex. To characterize the function of BCL7B, heterozygous BCL7B-deficient stomach cancer cell lines were generated with the CRISPR/Cas9 genome editing system. The comprehensive gene expression patterns were compared between parental cells and each ΔBCL7B cell line by RNA-seq. The results showed marked downregulation of immune-related genes and upregulation of stemness-related genes in the ΔBCL7B cell lines. Moreover, by ChIP-seq analysis with H3K27me3 antibody, the changes of epigenetic modification sequences were compared between parental cells and each ΔBCL7B cell line. After machine learning, we detected the centroid sequence changes, which exerted an impact on antigen presentation. The regulation of BCL7B expression in cancer cells gives rise to cancer stem cell-like characteristics and the acquisition of an immune evasion phenotype

Correction: Adipose Tissue-Derived Mesenchymal Stem Cells in Long-Term Dialysis Patients Display Downregulation of PCAF Expression and Poor Angiogenesis Activation.

[This corrects the article DOI: 10.1371/journal.pone.0102311.]

Adipose tissue-derived mesenchymal stem cells in long-term dialysis patients display downregulation of PCAF expression and poor angiogenesis activation.

We previously demonstrated that mesenchymal stem cells (MSCs) differentiate into functional kidney cells capable of urine and erythropoietin production, indicating that they may be used for kidney regeneration. However, the viability of MSCs from dialysis patients may be affected under uremic conditions. In this study, we isolated MSCs from the adipose tissues of end-stage kidney disease (ESKD) patients undergoing long-term dialysis (KD-MSCs; mean: 72.3 months) and from healthy controls (HC-MSCs) to compare their viability. KD-MSCs and HC-MSCs were assessed for their proliferation potential, senescence, and differentiation capacities into adipocytes, osteoblasts, and chondrocytes. Gene expression of stem cell-specific transcription factors was analyzed by PCR array and confirmed by western blot analysis at the protein level. No significant differences of proliferation potential, senescence, or differentiation capacity were observed between KD-MSCs and HC-MSCs. However, gene and protein expression of p300/CBP-associated factor (PCAF) was significantly suppressed in KD-MSCs. Because PCAF is a histone acetyltransferase that mediates regulation of hypoxia-inducible factor-1α (HIF-1α), we examined the hypoxic response in MSCs. HC-MSCs but not KD-MSCs showed upregulation of PCAF protein expression under hypoxia. Similarly, HIF-1α and vascular endothelial growth factor (VEGF) expression did not increase under hypoxia in KD-MSCs but did so in HC-MSCs. Additionally, a directed in vivo angiogenesis assay revealed a decrease in angiogenesis activation of KD-MSCs. In conclusion, long-term uremia leads to persistent and systematic downregulation of PCAF gene and protein expression and poor angiogenesis activation of MSCs from patients with ESKD. Furthermore, PCAF, HIF-1α, and VEGF expression were not upregulated by hypoxic stimulation of KD-MSCs. These results suggest that the hypoxic response may be blunted in MSCs from ESKD patients

Generation of a felinized swine endothelial cell line by expression of feline decay-accelerating factor.

Embryonic stem cell research has facilitated the generation of many cell types for the production of tissues and organs for both humans and companion animals. Because ≥30% of pet cats suffer from chronic kidney disease (CKD), xenotransplantation between pigs and cats has been studied. For a successful pig to cat xenotransplant, the immune reaction must be overcome, especially hyperacute rejection. In this study, we isolated the gene for feline decay-accelerating factor (fDAF), an inhibitor of complement proteins, and transfected a swine endothelial cell line with fDAF to "felinize" the pig cells. These fDAF-expressing cells were resistant to feline serum containing anti-pig antibodies, suggesting that felinized pig cells were resistant to hyperacute rejection. Our results suggest that a "felinized" pig kidney can be generated for the treatment of CKD in cats in the future

Proliferation and senescence of HC-MSCs and KD-MSCs.

<p>(A) Representative images of HC-MSCs and KD-MSCs (magnification, ×40). Left columns show assessment of senescence using the senescence biomarker SA-β-gal (green) in HC-MSCs and KD-MSCs. Black scale bars represent 50 µm. Right columns show DAPI staining of senescence-associated heterochromatic foci (SAHF) in MSC DNA foci. White scale bars represent 10 µm. Insets show an enlargement of DAPI staining (white scale bars represent 5 µm). Early passage: P5; late passage: P10. (B) Quantitative assessment of SA-β-gal positive cells. Data are the mean ± SE (<i>n</i> = 4). ^*<i>P</i><0.05. (C) Cumulative population doublings (PDs) of HC-MSCs (<i>n</i> = 5) and KD-MSCs (<i>n</i> = 5) from passage 5–10. Data are expressed as the mean ± SE. ^*<i>P</i><0.05. Experiments were performed in triplicate.</p

Differentiation capacities of HC-MSCs and KD-MSCs.

<p>(A) Adipogenic differentiation of HC-MSCs (top and left) and KD-MSCs (top and right) was examined after 2 weeks of culture under adipogenic conditions by Sudan III staining (original magnification, ×100). Osteogenic differentiation of HC-MSCs (second from top and left) and KD-MSCs (second from top and right) was examined after 4 weeks of culture under osteogenic conditions by von Kossa staining (original magnification, ×100). Chondrogenic differentiation of HC-MSCs (bottom and left) and KD-MSCs (bottom and right) was examined after 3 weeks of culture under chondrogenic conditions by Safranin O/Fast green staining (original magnification, ×100). (B) GPDH activity of cells was measured to compare the adipogenic differentiation capacities of HC-MSCs (<i>n</i> = 5) and KD-MSCs (<i>n</i> = 5). Data are expressed as the mean ± standard error (SE). ^*<i>P</i><0.05. (C) ALP activity of the cells was measured to indicate their osteogenic differentiation capacity (<i>n</i> = 4). Data are expressed as the mean ± SE. ^*<i>P</i><0.05.</p

Differences in mRNA expression between KD-MSCs and HC-MSCs by RT-PCR analysis.

<p>*p<0.05 between HC-MSCs (n = 6) and KD-MSCs (n = 9).</p

Real-time PCR array, quantitative PCR, and western blot analyses of MSCs.

<p>(A) Downregulation of multiple stem cell-relevant transcription factors in KD-MSCs (<i>n</i> = 9) compared with HC-MSCs (<i>n</i> = 6). The fold change [2∧(−ΔΔCt)] is the normalized gene expression [2∧(−ΔCt)] in KD-MSCs relative to that in HC-MSCs. <i>P</i>-values were calculated based on the Student's <i>t</i>-test of replicate 2∧(−ΔCt) values for each gene in HC-MSCs and KD-MSCs. <i>P</i><0.05 is indicated with black arrows. (B) Quantitative PCR was performed to measure the levels of gene expression in HC-MSCs (<i>n</i> = 6) and KD-MSCs (<i>n</i> = 6). Data are expressed as the mean ± SE. ^*<i>P</i><0.05. (C) Western blot analysis of PCAF in KD-MSCs and HC-MSCs. PCAF expression was decreased in KD-MSCs (<i>n</i> = 9) compared with HC-MSCs (<i>n</i> = 6). PCAF protein levels are expressed relative to β-actin. Data are expressed as the mean ± SE. ^*<i>P</i><0.05.</p