Background: Natural killer (NK) cell-based immunotherapy is clinically limited due to insufficient tumor infiltration in solid tumors. We have previously found that the natural product rocaglamide (RocA) can enhance NK cell-mediated killing of non-small cell lung cancer (NSCLC) cells by inhibiting autophagy, and autophagic inhibition has been shown to increase NK cell tumor infiltration in melanoma. Therefore, we hypothesized that RocA could increase NK cell infiltration in NSCLC by autophagy inhibition.

Targeting macroautophagy/autophagy is a novel strategy in cancer immunotherapy. In the present study, we showed that the natural product rocaglamide (RocA) enhanced natural killer (NK) cell-mediated lysis of non-small cell lung cancer (NSCLC) cells in vitro and tumor regression in vivo. Moreover, this effect was not related to the NK cell recognition of target cells or expressions of death receptors. Instead, RocA inhibited autophagy and restored the level of NK cell-derived GZMB (granzyme B) in NSCLC cells, therefore increasing their susceptibility to NK cell-mediated killing. In addition, we further identified that the target of RocA was ULK1 (unc-51 like autophagy activating kinase 1) that is required for autophagy initiation. Using firefly luciferase containing the 5´ untranslated region of ULK1, we found that RocA inhibited the protein translation of ULK1 in a sequence-specific manner. Taken together, RocA could block autophagic immune resistance to NK cell-mediated killing, and our data suggested that RocA was a promising therapeutic candidate in NK cell-based cancer immunotherapy.

NKG2D is a major activating receptor of NK cells and plays a critical role in tumor immunosurveillance. NKG2D expression in NK cells is inhibited by the histone deacetylase (HDAC) inhibitor valproic acid (VPA) and enhanced by the narrow-spectrum HDAC inhibitor entinostat. We previously demonstrated that entinostat enhanced NKG2D transcription by increasing acetylation of Histones H3 and H4. However, the mechanism by which VPA reduces NKG2D expression in NK cells is not known. We have also shown that NKG2D transcription is regulated by STAT3 phosphorylation. In this study, we investigated regulation of NKG2D expression in NK cells by VPA and entinostat by assessing protein expression, phosphorylation, and interaction of HDACs and STAT3. We find that VPA selectively inhibits STAT3 tyrosine705 phosphorylation, but entinostat does not. STAT3 complexes with HDAC3, and HDAC3 inhibition represses STAT3 phosphorylation and therefore NKG2D expression. NK cells from STAT3 wild-type mice downregulate NKG2D in response to VPA, but not NK cells from STAT3 knockout mice. These results show that VPA is a potent inhibitor of STAT3 phosphorylation and demonstrate that histone acetylation and STAT3 tyrosine705 phosphorylation cooperate in regulating NKG2D expression in NK cells.

The identification of bioactive compounds from Chinese medicine plays a crucial role in the development of novel reagents against non-small lung cancer (NSCLC). High throughput screening assay and analyses of cell growth, cell cycle, apoptosis, cDNA microarray, BrdU incorporation and gene expression were performed. Ailanthone (Aila) suppressed NSCLC cell growth and colony formation in vitro and inhibited NSCLC tumour growth in subcutaneously xenografted and orthotopic lung tumour models, leading to prolonged survival of tumour-bearing mice. Moreover, Aila induced cell cycle arrest in a dose-independent manner but did not induce apoptosis in all NSCLC cells. Furthermore, 1222 genes were differentially expressed upon Aila administration, which were involved in 21 signal pathways, such as DNA replication. In addition, Aila dose-dependently decreased BrdU incorporation and downregulated the expression of replication protein A1 (RPA1). Aila inhibited the growth of NSCLC cells through the repression of DNA replication via downregulating RPA1, rather than through cell cycle arrest and apoptosis. Our findings suggested that Aila could be used as a promising therapeutic candidate for NSCLC patients.

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.

Non–small‐cell lung cancer (NSCLC) has become the most lethal human cancer because of the high rate of metastasis. Hence, clarifying the molecular mechanism underlying NSCLC metastasis is very important to improve the prognosis of patients with NSCLC. Long non‐coding RNAs (LncRNAs) are a class of RNA molecules longer than 200 nucleotides, which can participate in diverse biological processes. About 18% of human LncRNAs were recently found to be associated with tumours. Many studies indicated that aberrant expression of LncRNAs played key roles in the progression and metastasis of NSCLC. According to the function in tumours, LncRNAs can be divided into two classes: oncogenic LncRNAs and tumour‐suppressor LncRNAs. In this review, we summarized the main molecular mechanism of LncRNAs regulating NSCLC metastasis, including three aspects: (a) LncRNAs interact with miRNAs as ceRNAs; (b) LncRNAs bind with target proteins; and (c) LncRNAs participate in the transduction of different signal pathways. Then, LncRNAs can exert their function to regulate the metastasis of NSCLC through influencing the progression of epithelial‐mesenchymal transition (EMT) and the properties of cancer stem cell (CSC). But, it is necessary to do some further research to demonstrate the LncRNAs particular regulatory mechanism of inhibiting the metastasis of NSCLC and explore new drugs targeting LncRNAs.