CCL8 secreted by tumor-associated macrophages promotes invasion and stemness of glioblastoma cells via ERK1/2 signaling.

Tumor-associated macrophages (TAMs) constitute a large population of glioblastoma and facilitate tumor growth and invasion of tumor cells, but the underlying mechanism remains undefined. In this study, we demonstrate that chemokine (C-C motif) ligand 8 (CCL8) is highly expressed by TAMs and contributes to pseudopodia formation by GBM cells. The presence of CCL8 in the glioma microenvironment promotes progression of tumor cells. Moreover, CCL8 induces invasion and stem-like traits of GBM cells, and CCR1 and CCR5 are the main receptors that mediate CCL8-induced biological behavior. Finally, CCL8 dramatically activates ERK1/2 phosphorylation in GBM cells, and blocking TAM-secreted CCL8 by neutralized antibody significantly decreases invasion of glioma cells. Taken together, our data reveal that CCL8 is a TAM-associated factor to mediate invasion and stemness of GBM, and targeting CCL8 may provide an insight strategy for GBM treatment.

Zyxin (ZYX) promotes invasion and acts as a biomarker for aggressive phenotypes of human glioblastoma multiforme.

Glioblastoma multiforme (GBM) is characterized by highly invasive growth, which leads to extensive infiltration and makes complete tumor excision difficult. Since cytoskeleton proteins are related to leading processes and cell motility, and through analysis of public GBM databases, we determined that an actin-interacting protein, zyxin (ZYX), may involved in GBM invasion. Our own glioma cohort as well as the cancer genome atlas (TCGA), Rembrandt, and Gravendeel databases consistently showed that increased ZYX expression was related to tumor progression and poor prognosis of glioma patients. In vitro and in vivo experiments further confirmed the oncogenic roles of ZYX and demonstrated the role of ZYX in GBM invasive growth. Moreover, RNA-seq and mass-spectrum data from GBM cells with or without ZYX revealed that stathmin 1 (STMN1) was a potential target of ZYX. Subsequently, we found that both mRNA and protein levels of STMN1 were positively regulated by ZYX. Functionally, STMN1 not only promoted invasion of GBM cells but also rescued the invasion repression caused by ZYX loss. Taken together, our results indicate that high ZYX expression was associated with worse prognosis and highlighted that the ZYX-STMN1 axis might be a potential therapeutic target for GBM.

A 3D screening approach identifies the compound epitajixanthone hydrate as a new inhibitor of cancer cell growth and invasion.

With unique advantages, the small-molecule anticancer drugs have recently gained growing attention. Particular strategies, exemplified by high-throughput screening, fragment-based drug discovery, virtual screening and knowledge-based design, have been developed to identify active compounds. However, such screens generally rely on sophisticated and expensive instrumentations. Herein, we developed a simple spheroids 3D culture system to enable direct screening of small molecules with reliable results. Using this system, we screened 27 fungal natural products and three fungal crude extracts for their inhibitory effects on cancer cell growth, and invasion. We identified that the compound M23 (epitajixanthone hydrate, a derivative of prenylxanthone) and the crude extracts (MPT-191) from the fungi Taxus chinensis showed potential anticancer activity. The effect of epitajixanthone hydrate on cancer cell growth and invasion were further confirmed by the assays of cells viability, trans-well migration and invasion, colony formation and cells reattachment. Overall, Epitajixanthone hydrate was identified as an effective inhibitor of cancer cell growth and invasion by our simple and fast screening platform.

Prenylated Indole Diterpene Alkaloids from a Mine-Soil-Derived Tolypocladium sp.

Ten new prenylated indole diterpene alkaloids, tolypocladin A-J (1-10), including four chlorinated metabolites, have been isolated from a culture of a mine-soil-derived fungus, Tolypocladium sp. XL115. The structures and absolute configurations of 1-10 were determined by spectroscopic analysis, ECD calculations, and comparison with known compounds. Compounds 1 and 8 displayed significant antimicrobial activities. In addition, compound 1 also showed weak cytotoxic activity against all tested human cancer cell lines and suppressed the growth and viability of the patient-derived HCC cells T1224.

Stromal PD-1+ tumor-associated macrophages predict poor prognosis in lung adenocarcinoma.

Immunotherapies targeting programmed cell death protein 1 (PD-1)/PD-1 ligand (PD-L1) axis have been emerging as a promising therapeutic strategy to treat lung cancer. PD-1 is preferentially expressed by activated T lymphocytes; but whether/how its expression by tumor-associated macrophages (TAMs) in lung adenocarcinoma remains elusive. Herein, we investigate the frequency of PD-1 expression on TAMs in mouse allografts by flow cytometry analysis and evaluate the spatial distribution and clinicopathological significance of PD-1+ TAMs in 213 cases of human lung adenocarcinoma specimens by immunohistochemical staining. We find the expression of PD-1 by both mouse and human TAMs. Mouse PD-1+ TAMs possess unique transcriptional profile as compared to PD-1- TAMs. Furthermore, PD-1 is preferentially expressed by CD163+ TAMs in the tumor stroma than those in the tumor islets of lung adenocarcinoma. Stromal PD-1+ TAM infiltration is an independent predictor of reduced survival as determined by univariate (P < .001) and multivariate (P = .023) analysis. Moreover, patients with high stromal PD-1+ TAMs but low tumor cell PD-L1 expression have the shortest survival (P = .0001). Our study demonstrates that PD-1+ TAMs have unique gene expression characteristics and PD-1+ TAMs in the tumor stroma is a potential prognostic factor in lung adenocarcinoma, suggesting that a better understanding of PD-1+ TAMs will be beneficial for immunotherapy of lung adenocarcinoma patients.

The landscape of immune microenvironment in lung adenocarcinoma and squamous cell carcinoma based on PD-L1 expression and tumor-infiltrating lymphocytes.

AIMS: The aim of this study was to investigate the tumor microenvironment immune types (TMIT) based on tumor cell programmed cell death ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) distribution and whether distinct TMIT subtypes (TMIT I, PD-L1high /TILhigh ; TMIT II, PD-L1low /TILlow ; TMIT III, PD-L1high /TILlow ; and TMIT IV, PD-L1low /TILhigh ) differentially affect clinical outcomes of patients with lung adenocarcinoma (LAC) and squamous cell carcinoma (SCC). METHODS AND RESULTS: Immunohistochemistry (IHC) was applied to evaluate the expression of PD-L1 and the spatial distribution of programmed cell death 1 (PD-1) and CD8 TILs on the surgically resected specimens from 205 cases of LAC and 149 cases of SCC. PD-1 and CD8 TILs were more frequently distributed in SCC than those in LAC, regardless of their infiltrating in the tumor islets or stroma. The density of TILs was a poor prognostic factor in LAC but a favorable one in SCC. PD-L1 levels and its clinical prognostic significance differed in LAC vs SCC. LAC patients with TMIT III and SCC patients with TMIT I had the longest survival, respectively (P = .0197 and .0049). Moreover, TMIT stratification based on tumor cell PD-L1 expression and stromal CD8+ TILs could be considered as an independent prognostic factor of SCC patients' survival as determined by both univariate and multivariate analysis. CONCLUSION: Our study indicates that different type of TMIT provides its specific microenvironment with diverse impact on survival of LAC and SCC patients and highlights the importance of the integrative assessment of PD-L1 status and TILs' spatial distribution to predict patients' prognosis.