title: Combination of IFNα and poly-I:C reprograms bladder cancer microenvironment for enhanced CTL attraction.
abstract: BACKGROUND
  BCG is a prototypal cancer immunotherapeutic factor currently approved of bladder cancer. In attempt to further enhance the effectiveness of immunotherapy of bladder cancer and, potentially, other malignancies, we evaluated the impact of BCG on local production of chemokines attracting the desirable effector CD8(+) T cells (CTLs) and undesirable myeloid-derived suppressor cell (MDSCs) and regulatory T(reg) cells, and the ability of bladder cancer tissues to attract CTLs.
  
  
  METHODS
  Freshly resected bladder cancer tissues were either analyzed immediately or cultured ex vivo in the absence or presence of the tested factors. The expression of chemokine genes, secretion of chemokines and their local sources in freshly harvested and ex vivo-treated tumor explants were analyzed by quantitative PCR (Taqman), ELISAs and immunofluorescence/confocal microscopy. Migration of CTLs was evaluated ex vivo, using 24-transwell plates. Spearman correlation was used for correlative analysis, while paired Students T test or Wilcoxon was used for statistical analysis of the data.
  
  
  RESULTS
  Bladder cancer tissues spontaneously expressed high levels of the granulocyte/MDSC-attractant CXCL8 and Treg-attractant CCL22, but only marginal levels of the CTL-attracting chemokines: CCL5, CXCL9 and CXCL10. Baseline CXCL10 showed strong correlation with local expression of CTL markers. Unexpectedly, BCG selectively induced only the undesirable chemokines, CCL22 and CXCL8, but had only marginal impact on CXCL10 production. In sharp contrast, the combination of IFNα and a TLR3 ligand, poly-I:C (but not the combinations of BCG with IFNα or BCG with poly-I:C), induced high levels of intra-tumoral production of CXCL10 and promoted CTL attraction. The combination of BCG with IFNα + poly-I:C regimen did not show additional advantage.
  
  
  CONCLUSIONS
  The current data indicate that suboptimal ability of BCG to reprogram cancer-associated chemokine environment may be a factor limiting its therapeutic activity. Our observations that the combination of BCG with (or replacement by) IFNα and poly-I:C allows to reprogram bladder cancer tissues for enhanced CTL entry may provide for new methods of improving the effectiveness of immunotherapy of bladder cancer, helping to extend BCG applications to its more advanced forms, and, potentially, other diseases.
authors: Departments of Sugery, University of Pittsburgh, Pittsburgh, PA 15213 USA.
authors: Ravikumar
authors: R
authors: Muthuswamy
authors: Departments of Sugery, University of Pittsburgh, Pittsburgh, PA 15213 USA.
authors: Liwen
authors: L
authors: Wang
authors: Departments of Sugery, University of Pittsburgh, Pittsburgh, PA 15213 USA.
authors: Jamie
authors: J
authors: Pitteroff
authors: Department of Urology, University of Pittsburgh, Pittsburgh, PA 15213 USA.
authors: Jeffrey R
authors: JR
authors: Gingrich
authors: Departments of Sugery, University of Pittsburgh, Pittsburgh, PA 15213 USA ; Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh, PA 15213 USA ; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213 USA ; University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213 USA ; Department of Surgery, University of Pittsburgh, Hillman Cancer Center, UPCI Research Pavilion, Room 1.46b, 5117 Center Avenue, Pittsburgh, PA 15213 USA.
authors: Pawel
authors: P
authors: Kalinski
keywords: BCG; Bladder cancer; Chemokines; Effector T cells; IFNα; Immunomodulation; Poly-I :C; Regulatory T cells; TLR3; Tumor microenvironment