TNC staining scores were assigned as follows: score 1 weak staining in 50% or moderate staining in 20%; score 2, weak staining in R50%, moderate staining in 20C50% or strong staining in 20%; score 3, moderate staining in R50% or strong staining R20%
TNC staining scores were assigned as follows: score 1 weak staining in 50% or moderate staining in 20%; score 2, weak staining in R50%, moderate staining in 20C50% or strong staining in 20%; score 3, moderate staining in R50% or strong staining R20%. deposited in the ProteomeXchange Consortium via the PRIDE49 partner repository with the dataset identifier PXD019946; The mass spectrometry proteomics data of the indicated MEF cell lines have been deposited in the ProteomeXchange Consortium via the PRIDE49 partner repository with the dataset identifier PXD019947. All the other data that support the findings of this study are available from the corresponding author upon reasonable request. The source data underlying Figs. ?Figs.2a,2a, d, f, h, k, ?k,3b,3b, d, e, ?e,4aCd,4aCd, f, h, ?h,5aCf,5aCf, 6a, cCe, 9a and AT-101 Supplementary Figs. 2aCf, i, j, l, n, p, 3aCb, 4d, e, h, i, j, 5bCg, 6a, b, and 11a are provided as a Source Data file.?Source data are provided with this paper. Abstract Most triple-negative breast cancer (TNBC) patients fail to respond to T cell-mediated immunotherapies. Unfortunately, the molecular determinants are still poorly comprehended. Breast cancer is the disease genetically linked to a deficiency in autophagy. Here, we show that autophagy defects in TNBC cells inhibit T cell-mediated tumour killing in vitro and in vivo. Mechanistically, we identify Tenascin-C as a candidate for autophagy deficiency-mediated immunosuppression, in which Tenascin-C is usually Lys63-ubiquitinated by Skp2, particularly at Lys942 and Lys1882, thus promoting its recognition by p62 and leading to its selective autophagic degradation. High Tenascin-C expression is associated with poor prognosis and inversely correlated with LC3B expression and CD8+ T cells in TNBC patients. More importantly, inhibition of Tenascin-C in autophagy-impaired TNBC cells sensitizes T cell-mediated tumour killing and improves antitumour effects of single anti-PD1/PDL1 therapy. Our results provide a potential strategy for targeting TNBC with the combination of Tenascin-C blockade and immune checkpoint inhibitors. value in (aCd, f) was determined by one-way ANOVA with Tukeys multiple comparisons test, the?value in (e) was determined by one-way ANOVA with Dunnetts multiple comparisons test, no adjustments were made for multiple comparisons. NS no significance. All data are representative of three impartial experiments. Then we further measured antigen-specific T-cell-mediated cytotoxicity?in autophagy-deficient MDA-MB-231 cells. Peptide 264C272 from naturally processed p53 has proven to be a potential T-cell epitope because of its strong affinity to HLA-A2, and MDA-MB-231 cells display high p53 concentrations in the nucleus due AT-101 to a p53 gene mutation in codon 28028,29. Our results also showed high levels of p53 protein in autophagy-deficient MDA-MB-231 cell lines, similar to the levels in autophagy-competent MDA-MB-231 cell lines (Supplementary Fig.?2n). In the experiment, DCs loaded with the P53264C272 antigen were co-cultured with autologous T lymphocytes from healthy HLA-A2+ donors to induce P53 peptide-specific T cells. T cells stimulated with no peptide-pulsed DCs were used as control T cells. The results showed that this frequency of P53264C272 tetramer+ CD8+ T cells increased from 0.12 to 2.2% after stimulation with P53264C272 peptide-pulsed DCs. As a control staining, NY-ESO-1157-165 tetramer+ CD8+ T cells were assessed, and they did not change obviously (Supplementary Fig.?2o). The cytotoxicity Rabbit Polyclonal to SCN9A of P53 peptide-pulsed DC-treated T cells targeting MDA-MB-231 cells was higher than that of control T cells (Fig.?1f). These data suggest that T cells stimulated with P53264-272 peptide-pulsed DCs could kill MDA-MB-231 cells specifically by recognition of endogenous p53 epitope presented by tumour cells. As expected, we observed that this cytotoxicity of P53-specific T cells against MDA-MB-231-Atg5KO cells was reduced, but the cytotoxicity was recovered when Atg5 was restored (Fig.?1f). In addition, we depleted Atg7 in ovalbumin (OVA)-positive melanoma B16F10 cells (Supplementary Fig.?2p). Then the cells were co-cultured with activated CD8+ T cells isolated from OT-1 TCR transgenic mice. The data also showed that compared to their autophagy-competent counterparts, autophagy-deficient B16F10-OVA-Atg7KO cells were more resistant to antigen-specific T-cell-mediated killing than the WT?cells (Supplementary Fig.?2q). Altogether, these data confirm that autophagy failure contributes to the limitation of T-lymphocyte attack on?TNBC cells. Autophagy deficiency reduces T-cell antitumor response To evaluate the effect of autophagy on T-cell-mediated antitumour activity in vivo, we established autophagy-deficient murine models. Mouse mammary basal-like carcinoma 4T1 cells were used to establish the autophagy-incompetent model, which was generated by the depletion of Atg5 or Beclin1 with specific sgRNAs. Western blotting was used to confirm the blockage of the formation of LC3B-II in 4T1-Atg5KO cells AT-101 and the decreased formation of LC3B-II in 4T1-Beclin1KO cells (Supplementary Fig.?3a). Consistent with the in vitro analysis, the autophagy-deficient 4T1-Atg5KO and 4T1-Beclin1KO tumours grew AT-101 faster than the autophagy-competent 4T1 control cells in immunocompetent BALB/c mice, which were confirmed by the growth curves of the xenograft tumour volumes and the tumour weights (Fig.?2a, Supplementary Fig.?3b). Furthermore, the tumors?induced by the autophagy-deficient 4T1 cells had not only decreased total AT-101 CD4+ and CD8+ TIL populations but.