Differential immunomodulatory effects of epirubicin/cyclophosphamide and docetaxel in breast cancer patients.

BACKGROUND: Epirubicin/cyclophosphamide (EC) and docetaxel (D) are commonly used in a sequential regimen in the neoadjuvant treatment of early, high-risk or locally advanced breast cancer (BC). Novel approaches to increase the response rate combine this treatment with immunotherapies such as PD-1 inhibition. However, the expected stimulatory effect on lymphocytes may depend on the chemotherapy backbone. Therefore, we separately compared the immunomodulatory effects of EC and D in the setting of a randomized clinical trial. METHODS: Tumor and blood samples of 154 patients from the ABCSG-34 trial were available (76 patients received four cycles of EC followed by four cycles of D; 78 patients get the reverse treatment sequence). Tumor-infiltrating lymphocytes, circulating lymphocytes and 14 soluble immune mediators were determined at baseline and at drug change. Furthermore, six BC cell lines were treated with E, C or D and co-cultured with immune cells. RESULTS: Initial treatment with four cycles of EC reduced circulating B and T cells by 94% and 45%, respectively. In contrast, no comparable effects on lymphocytes were observed in patients treated with initial four cycles of D. Most immune mediators decreased under EC whereas D-treatment resulted in elevated levels of CXCL10, urokinase-type plasminogen activator (uPA) and its soluble receptor (suPAR). Accordingly, only the exposure of BC cell lines to D induced similar increases as compared to E. While treatment of BC cells with E was associated with cell shrinkage and apoptosis, D induced cell swelling and accumulation of cells in G2 phase. CONCLUSION: The deleterious effect of EC on lymphocytes indicates strong immunosuppressive properties of this combination therapy. D, in contrast, has no effect on lymphocytes, but triggers the secretion of stimulatory proteins in vivo and in vitro, indicating a supportive effect on the immune system. Underlying differences in the induced cell death might be causal. These divergent immunomodulatory effects of epirubicin/cyclophosphamide and docetaxel should be considered when planning future combinations with immunotherapies in breast cancer.

Immunological differences between colorectal cancer and normal mucosa uncover a prognostically relevant immune cell profile.

T cells in colorectal cancer (CRC) are associated with improved survival. However, checkpoint immunotherapies antagonizing the suppression of these cells are ineffective in the great majority of patients. To better understand the immune cell regulation in CRC, we compared tumor-associated T lymphocytes and macrophages to the immune cell infiltrate of normal mucosa. Human colorectal tumor specimen and tumor-distant normal mucosa tissues of the same patients were collected. Phenotypes and functionality of tissue-derived T cells and macrophages were characterized using immunohistochemistry, RNA in situ hybridization, and multiparameter flow cytometry. CRC contained significantly higher numbers of potentially immunosuppressive CD39 and Helios-expressing regulatory T cells in comparison to normal mucosa. Surprisingly, we found a concomitant increase of pro-inflammatory IFNγ -producing T cells. PD-L1+ stromal cells were decreased in the tumor tissue. Macrophages in the tumor compared to tumor-distant normal tissue appear to have an altered phenotype, identified by HLA-DR, CD14, CX3CR1, and CD64, and tolerogenic CD206+ macrophages are quantitatively reduced. The prognostic effect of these observed differences between distant mucosa and tumor tissue on the overall survival was examined using gene expression data of 298 CRC patients. The combined gene expression of increased FOXP3, IFNγ, CD14, and decreased CD206 correlated with a poor prognosis in CRC patients. These data reveal that the CRC microenvironment promotes the coexistence of seemingly antagonistic suppressive and pro-inflammatory immune responses and might provide an explanation why a blockade of the PD1/PD-L1 axis is ineffective in CRC. This should be taken into account when designing novel treatment strategies.

In Situ Characterization of Tissue-Resident Immune Cells by MALDI Mass Spectrometry Imaging.

Tissue-resident immune cells differ from their corresponding blood cells in many functional aspects. Although the proteome of blood immune cells has been well-investigated, there are almost no data on tissue-resident immune cells. Here, we explored the potential of using MALDI-TOF-MS imaging (MSI) to investigate these cells in colon tissue, which exhibits a strong infiltration of immune cells. MSI identified several proteinaceous markers that colocalized with specific structures of the colon, such as mucosa or muscularis mucosae, in six patients. In addition, we showed that certain m/z values have the same spatial distribution as CD3+ T lymphocytes in the lymphoid follicular structures or as CD206+ macrophages in the lamina propria. For further corroboration, blood lymphocytes and monocytes from 10 healthy volunteers were analyzed by intact cell mass spectrometry (ICMS). Furthermore, we analyzed monocyte-derived macrophages that had been polarized in vitro into proinflammatory M1 and anti-inflammatory M2 phenotypes. The mass spectra differed clearly among all immune cell types. Additionally, it was found that distinct signals from ICMS analysis were identical to the m/z values found in the MSI experiment in lymphoid follicular structures. These data show for the first time that MSI is well-suited to visualize the spatial distribution of immune cells in human colon tissue. We consider MALDI mass spectrometry imaging to be a technique with high potential for use in rapid investigations of tissue-specific features of cells.