title: PhiC31/PiggyBac modified stromal stem cells: effect of interferon γ and/or tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) on murine melanoma.
abstract: BACKGROUND
  TRAIL and IFNγ are promising anti-cancer cytokines and it has been shown that IFNγ may sensitize cancer cells to TRAIL. Adipose derived mesenchymal stem cells (ADSCs) are attractive vehicles for delivering anti-cancer agents. In this study, we evaluated the therapeutic potential of PhiC31 (φC31) recombinase and/or piggyBac transposase (pBt) modified ADSCs expressing either TRAIL, IFNγ, or co-expressing TRAIL/IFNγ in mouse models of melanoma.
  
  
  METHODS
  The expression and bioactivity of mouse IFNγ and TRAIL in φC31 and pBt modified cells were confirmed. We examined the effects of modified ADSCs on signal intensity of red fluorescence protein expressed by melanoma cells in subcutaneous tumors or established lung metastases and on survival (6 mice per group). We also conducted a flow cytometric analysis of systemic CD4(+)CD25(+)FOXP3(+) T regulatory cells (Tregs) and histological analysis of melanoma tumors. Data were analyzed by Student t test, ANOVA, and log-rank tests. All statistical tests were two-sided.
  
  
  RESULTS
  We demonstrated non-viral DNA-integrating vectors can be used for stable transgene expression. IFNγ inhibited melanoma cell growth in vitro probably via IFNγ-induced JAK/STAT1 signaling pathway activation. Murine TRAIL induced apoptosis in the human cell lines CAOV-4 and Ej-138, while MCF7 and B16F10 cells appeared to be insensitive to TRAIL. Treatment of melanoma cells with IFNγ did not influence their response to TRAIL. In contrast, results from in vivo studies showed that IFNγ-expressing ADSCs, engrafted into tumor stroma, inhibited tumor growth and angiogenesis, prevented systemic increase of Tregs, increased PD-L1 expression and CD8+ infiltration (but not interleukin-2+ cells), and prolonged the survival of mice (68 days, 95% confidence interval [CI] = 52 to 86 days compared to 36 days, 95% CI = 29 to 39 days for control, P < .001).
  
  
  CONCLUSIONS
  For the first time, we employed DNA integrating vectors for safe and stable modification of MSCs. Our data indicate potential of non-virally modified IFNγ-expressing ADSCs for treatment of melanoma through direct effects of IFNγ. This study may have a significant role in the management of cancer in the future.
authors.forename: Vahid
authors.initials: V
authors.lastname: Bahrambeigi
authors.forename: Nafiseh
authors.initials: N
authors.lastname: Ahmadi
authors.forename: Stefan
authors.initials: S
authors.lastname: Moisyadi
authors.forename: Johann
authors.initials: J
authors.lastname: Urschitz
authors.forename: Rasoul
authors.initials: R
authors.lastname: Salehi
authors.affiliation: Applied Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. sh_haghjoo@med.mui.ac.ir.
authors.forename: Shaghayegh
authors.initials: S
authors.lastname: Haghjooy Javanmard
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D007376:Interleukin-2 / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism; D061986:MCF-7 Cells; D008297:Male; D008545:Melanoma / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000378:metabolism; D045522:Recombinases / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*; D019895:Transposases / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D007376:Interleukin-2; D009419:Nerve Tissue Proteins; D045522:Recombinases; D053221:TNF-Related Apoptosis-Inducing Ligand; D007371:Interferon-gamma; D019895:Transposases