Rocaglamide promotes infiltration and differentiation of T cells and coordinates with PD-1 inhibitor to overcome checkpoint resistance in multiple tumor models.

Tumor-infiltrating lymphocyte (TIL) deficiency is the most conspicuous obstacle to limit the cancer immunotherapy. Immune checkpoint inhibitors (ICIs), such as anti-PD-1 antibody, have achieved great success in clinical practice. However, due to the limitation of response rates of ICIs, some patients fail to benefit from monotherapy. Thus, novel combination therapy that could improve the response rates emerges as new strategies for cancer treatment. Here, we reported that the natural product rocaglamide (RocA) increased tumor-infiltrating T cells and promoted Th17 differentiation of CD4+ TILs. Despite RocA monotherapy upregulated PD-1 expression of TILs, which was considered as the consequence of T cell activation, combining RocA with anti-PD-1 antibody significantly downregulated the expression of PD-1 and promoted proliferation of TILs. Taken together, these findings demonstrated that RocA could fuel the T cell anti-tumor immunity and revealed the remarkable potential of RocA as a therapeutic candidate when combining with the ICIs.

Tanshinone IIA enhances susceptibility of non-small cell lung cancer cells to NK cell-mediated lysis by up-regulating ULBP1 and DR5.

Natural killer (NK) cells have a great potential in cancer immunotherapy. However, their therapeutic efficacy is clinically limited owing to cancer cell immune escape. Therefore, it is urgently necessary to develop novel method to improve the antitumor immunity of NK cells. In the present study, it was found that the natural product tanshinone IIA (TIIA) enhanced NK cell-mediated killing of non-small cell lung cancer (NSCLC) cells. TIIA in combination with adoptive transfer of NK cells synergistically suppressed the tumor growth of NSCLC cells in an immune-incompetent mouse model. Furthermore, TIIA significantly inhibited the tumor growth of Lewis lung cancer (LLC) in an immune-competent syngeneic mouse model, and such inhibitory effect was reversed by the depletion of NK cells. Moreover, TIIA increased expressions of ULBP1 and DR5 in NSCLC cells, and inhibition of DR5 and ULBP1 reduced the enhancement of NK cell-mediated lysis by TIIA. Besides, TIIA increased the levels of p-PERK, ATF4 and CHOP. Knockdown of ATF4 completely reversed the up-regulation of ULBP1 and DR5 by TIIA in all detected NSCLC cells, while knockdown of CHOP only partly reduced these enhanced expressions in small parts of NSCLC cells. These results demonstrated that TIIA could increase the susceptibility of NSCLC cells to NK cell-mediated lysis by up-regulating ULBP1 and DR5, suggesting that TIIA had a promising potential in cancer immunotherapy, especially in NK cell-based cancer immunotherapy.

Targeting CD155 by rediocide-A overcomes tumour immuno-resistance to natural killer cells.

CONTEXT: Therapeutic benefits of immunotherapy are restricted by cancer immune-resistance mechanisms. Rediocide-A (Red-A), a natural product extracted from Traditional Chinese Medicine, is a promising agent to battle against cancer which acts as an immune checkpoint inhibitor. OBJECTIVE: To investigate the effect of Red-A on NK-cell tumouricidal activity. MATERIALS AND METHODS: NK cells were co-cultured with A549 or H1299 cells and treated with 10 or 100 nM Red-A for 24 h. Cells treated with 0.1% dimethyl sulphoxide (DMSO) was employed as vehicle control. NK cell-mediated cytotoxicity was detected by biophotonic cytotoxicity and impedance assay. Degranulation, granzyme B, NK cell-tumour cell conjugates and ligands profiling were detected by flow cytometry. Interferon-γ (IFN- γ) production was assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Red-A increased NK cell-mediated lysis of A549 cells by 3.58-fold (21.86% vs. 78.27%) and H1299 cells by 1.26-fold (59.18% vs. 74.78%), compared to vehicle control. Granzyme B level was increased by 48.01% (A549 cells) and 53.26% (H1299 cells) after 100 nM Red-A treatment. INF-γ level was increased by 3.23-fold (A549 cells) and 6.77-fold (H1299 cells) after 100 nM Red-A treatment. Red-A treatment down-regulated the expression level of CD155 by 14.41% and 11.66% in A549 cells and H1299 cells, respectively, leading to the blockade of tumour immuno-resistance to NK cells. CONCLUSIONS: Red-A overcomes immuno-resistance of NSCLCs to NK cells by down-regulating CD155 expression, which shows the possibility of developing checkpoint inhibitors targeting TIGIT/CD155 signalling to overcome immuno-resistance of cancer cells.

A high-throughput assay for screening natural products that boost NK cell-mediated killing of cancer cells.

Context: Natural killer (NK) cells can eliminate malignant cells and play a vital role in immunosurveillance. Administration of natural compounds represents a promising approach for antitumor immunotherapy, which may enhance the NK cell activity via multiple mechanisms.Objective: Establishing approaches to evaluate the effect of select natural products on NK cell-mediated cytotoxicity.Materials and methods: We selected a natural product library containing 2880 pure compounds, which was provided by the National Centre for Drug Screening of China. 0.1% DMSO was employed as a negative control, and 100 U/mL human recombinant IL-2 was employed as a positive control. To evaluate the % of tumour cells which were killed by NK cells, expanded NK cells were co-cultured with tumour cells and then treated with natural products at the concentration of 10 µM. After 24-h co-incubation, luminescent signal was detected and percent lysis was calculated.Results: We report on the results of a three-round high-throughput screening effort that identified 20-deoxyingenol 3-angelate (DI3A) and its analogue ingenol 3-angelate (I3A) as immuno enhancers which boosts NK cell-mediated killing of non-small cell lung cancer cells (NSCLCs). Biophotonic cytotoxicity assay and calcein release assay were used as two well-established NK cell cytotoxicity detection assays to validate the immuno-enhancing effects of DI3A and I3A, which was achieved by increasing degranulation and interferon-gamma secretion of NK cells.Conclusions: Our newly established ATP-based method was a valuable and information-rich screening tool to investigate the biological effects of natural products on both NK cells and tumour cells.

The Ancient Chinese Decoction Yu-Ping-Feng Suppresses Orthotopic Lewis Lung Cancer Tumor Growth Through Increasing M1 Macrophage Polarization and CD4+ T Cell Cytotoxicity.

Background: The tumor microenvironment (TME) has a deep influence on cancer progression and has become into a new target for cancer treatment. In our previous study, we found that Yu-Ping-Feng (YPF), an ancient Chinese herbal decoction, significantly inhibited the Lewis lung cancer (LLC) tumor growth in a subcutaneous xenograft tumor model, and prolonged the survival of tumor-bearing mice. But the regulation of Yu-Ping-Feng on tumor microenvironment is unknown. Methods: To access the effect of Yu-Ping-Feng on non-small cell lung cancer, an orthotopic luciferase stably expressed Lewis lung cancer tumor model was established on C57BL/6 mice, and then the survival and the tumor growth were evaluated. To address the tumor microenvironment immune regulation, the percentages of CD4+ T cells, CD8+ T cells, natural killer cells (NK), regulatory T cells (Treg), macrophages, and myeloid-derived suppressor cells (MDSC) in spleens and tumor tissues, the macrophage polarization and CD4+ T cell cytotocixity were analyzed by flow cytometry, biophotonic cell killing activity assay, real-time PCR and western-blot. Results: Yu-Ping-Feng significantly prolonged orthotopic lung tumor-bearing mouse survival, and increased the percentages of CD4+ T cell and M1 macrophages and the cytotoxicity of CD4+ T cells. Yu-Ping-Feng significantly enhanced macrophage-mediated lysis of LLC in a concentration-dependent manner, and had no effect on CD4+ T cell-mediated lysis of LLC, but significantly increased CD4+ T cell-mediated lysis after co-incubated with macrophages. In addition, Yu-Ping-Feng induced M1 macrophage polarization through promoting the phosphorylation of STAT1. Conclusion: Yu-Ping-Feng induced M1 macrophages polarization, and then activated CD4+ T lymphocytes, resulting in killing of LLC cells. Yu-Ping-Feng was a potent regulator of M1 macrophage polarization and might have a promising application in tumor immunotherapy.