Nucleolin Therapeutic Targeting Decreases Pancreatic Cancer Immunosuppression

Abstract

Background: The pancreatic ductal adenocarcinoma (PDAC) microenvironment is highly fibrotic and hypoxic, with poor immune cell infiltration. Recently, we showed that nucleolin (NCL) inhibition normalizes tumour vessels and impairs PDAC growth. Methods: Immunocompetent mouse models of PDAC were treated by the pseudopeptide N6L, which selectively inhibits NCL. Tumour-infiltrating immune cells and changes in the tumour microenvironment were analysed. Results: N6L reduced the proportion of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) and increased tumour-infiltrated T lymphocytes (TILs) with an activated phenotype. Low-dose anti-VEGFR2 treatment normalized PDAC vessels but did not modulate the immune suppressive microenvironment. RNAseq analysis of N6L-treated PDAC tumours revealed a reduction of cancer-associated fibroblast (CAF) expansion in vivo and in vitro. Notably, N6L treatment decreased IL-6 levels both in tumour tissues and in serum. Treating mPDAC by an antibody blocking IL-6 reduced the proportion of Tregs and MDSCs and increased the amount of TILs, thus mimicking the effects of N6L. Conclusions: These results demonstrate that NCL inhibition blocks the amplification of lymphoid and myeloid immunosuppressive cells and promotes T cell activation in PDAC through a new mechanism of action dependent on the direct inhibition of the tumoral stroma.

TNFR2 blockade promotes anti-tumoral immune response in PDAC by targeting activated Treg and reducing T cell exhaustion

“…We sought to study the expression of TNFR2 by tumor infiltrated immune cells in orthotopic and immunocompetent mouse models of PDAC obtained by using mPDAC and Panc02 cell lines previously described [28]. We initially observed that mPDAC tumors have an immune-escape TME infiltrated by CD45 + immune cells, higly enriched in CD4 + Foxp3 + Tregs and characterized by low CD8 + T cell infiltration [29]. Here, tumor infiltrated lymphocytes (TILs) were isolated from mPDAC tumors and analyzed by flow cytometry.…”

“…Then, cell suspension was centrifuged in a gradient of Ficoll (GE Healthcare, ref: 17144003) for 40 min at 400g. All samples were stained as previously described [29] with the antibodies listed in Supplemental Material. Non-specific binding was blocked using anti-CD16/CD32 (Miltenyi, ref: 130-07-594).…”

Bioreactor-based stem cell therapy for liver fibrosis

“…Fourteen differentially expressed proteins were identified, of which 10 were upregulated and four were downregulated (figure 7(i)). Among the set of common differentially expressed proteins, NUTF2, NCL, COTL1, RAB1B, PFN1, moesin, PGK1, GAPDH, PDIA4, tenascin C, complement C6, complement C8, and CFHR4 were associated with immune regulation [16][17][18][19][20][21][22][23][24][25][26][27]. Therefore, the significant changes in protein levels in 5% FS-TM were mainly concentrated in immune regulatory proteins compared with those of other media.…”

Correction: Ponzo et al. Nucleolin Therapeutic Targeting Decreases Pancreatic Cancer Immunosuppression. Cancers 2022, 14, 4265

“…In the original publication [ 1 ], there was a mistake in Figure 3 A, Figure 6 E and Figure S1 A: there are white squares in the picture which cover the area that the authors want to indicate.…”