BackgroundGlioblastoma multiforme (GBM) is the most common primary central nervous system neoplasm in adults. Radioactive 125I seed implantation has been widely applied in the treatment of cancers. Moreover, previous clinical trials have confirmed that 125I seeds treatment was an effective therapy in GBM. We sought to investigate the effect of 125I seed on GBM cell growth and Epithelial-mesenchymal transition (EMT).MethodsCells were exposed to irradiation at different doses. Colony-formation assay, EdU assay, cell cycle analysis, and TUNEL assay were preformed to investigate the radiation sensitivity. The effects of 125I seeds irradiation on EMT were measured by transwell, Boyden and wound-healing assays. The levels of reactive oxygen species (ROS) were measured by DCF-DA assay. Moreover, the radiation sensitivity and EMT were investigated with or without pretreatment with glutathione. Additionally, nude mice with tumors were measured after treated with radiation.ResultsRadioactive 125I seeds are more effective than X-ray irradiation in inhibiting GBM cell growth. Moreover, EMT was effectively inhibited by 125I seed irradiation. A mechanism study indicated that GBM cell growth and EMT inhibition were induced by 125I seeds with the involvement of a ROS-mediated signaling pathway.ConclusionsRadioactive 125I seeds exhibit novel anticancer activity via a ROS-mediated signaling pathway. These findings have clinical implications for the treatment of patients with GBM by 125I seeds.

Fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] is cytotoxic in many cancer cell types. Studies have shown that elevation of ceramide species plays a role in 4-HPR cytotoxicity. To determine 4-HPR activity in a multidrug-resistant cancer cell line as well as to study ceramide metabolism, MCF-7/AdrR cells (redesignated NCI/ADR-RES) were treated with 4-HPR and sphingolipids were analyzed. TLC analysis of cells radiolabeled with [ 3 H]palmitic acid showed that 4-HPR elicited a doseresponsive increase in radioactivity migrating in the ceramide region of the chromatogram and a decrease in cell viability. Results from liquid chromatography/ electrospray tandem mass spectrometry revealed large elevations in dihydroceramides (N-acylsphinganines), but not desaturated ceramides, and large increases in complex dihydrosphingolipids (dihydrosphingomyelins, monohexosyldihydroceramides), sphinganine, and sphinganine 1-phosphate. To test the hypothesis that elevation of sphinganine participates in the cytotoxicity of 4-HPR, cells were treated with the sphingosine kinase inhibitor D-erythro-N,N -dimethylsphingosine (DMS), with and without 4-HPR. After 24 h, the 4-HPR/DMS combination caused a 9-fold increase in sphinganine that was sustained through +48 hours, decreased sphinganine 1-phosphate, and increased cytotoxicity. Increased dihydrosphingolipids and sphinganine were also found in HL-60 leukemia cells and HT-29 colon cancer cells treated with 4-HPR. The 4-HPR/DMS combination elicited increased apoptosis in all three cell lines. We propose that a mechanism of 4-HPR -induced cytotoxicity involves increases in dihydrosphingolipids, and that the synergy between 4-HPR and DMS is associated with large increases in cellular sphinganine. These studies suggest that enhanced clinical efficacy of 4-HPR may be realized through regimens containing agents that modulate sphingoid base metabolism. [Mol Cancer Ther 2008;7(9):2967 -76]

PIEZO channels are stretch-activated channels involved in wound sealing and cell proliferation in many cell types. A recent study focussing on lung cancer (LC), using next-generation sequencing analysis, has indicated that PIEZO functions were implicated in LC development. However, the expression and role of PIEZO channels in non-small cell LC (NSCLC) progression require elucidation. In the current study, we investigated the gene expression and alteration frequency in human NSCLC tissue, accessed the prognostic roles of PIEZO channels in NSCLC patients, and further studied the effect of PIEZOs in NSCLC cell proliferation and tumor growth in vivo. The mRNA expression of PIEZO1 and 2 was clearly decreased in NSCLC tumor tissue compared with that in matched adjacent non-tumor tissue. In human NSCLC tissues, PIEZO1 gene expression exhibits a highly deep deletion rate, and PIEZO2 mainly exhibits mutation in gene expression. High mRNA expression of PIEZO channels was found to correlate with better overall survival (OS) for NSCLC patients, especially for patients with lung adenocarcinoma (LUAD), but not for patients with lung squamous cell carcinoma (LUSC). The prognostic role of PIEZO channels was more sensitive in female patients than male patients, and more sensitive in patients at earlier stages than patients at latter stages. Knockdown of PIEZO1 or PIEZO2 in NSCLC cells significantly promoted cell migration in vitro and tumor growth in vivo. These results indicate the critical prognostic values of the PIEZO channels in NSCLC. This information will be beneficial to understand the pathological mechanism of NSCLC and to generate effective therapeutic approaches for NSCLC patients.

Highly malignant human gliomas overexpress the Gprotein-coupled chemoattractant receptor formyl peptide receptor (FPR1), which promotes tumor progression when activated. Our previous studies demonstrated that necrotic glioblastoma cells release chemotactic agonist(s) that activate FPR1 on viable tumor cells. In the present study, we identified an FPR1 agonist released by necrotic human glioblastoma cells.

Accumulating evidence has established that long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is a tumor regulator in many cancers. Here, we aimed to investigate the possible function of lncRNA PVT1 in esophageal carcinoma (EC) via targeting of microRNA‐145 (miR‐145). Initially, microarray‐based gene expression profiling of EC was employed to identify differentially expressed genes. Moreover, the expression of lncRNA PVT1 was examined and the cell line presenting with the highest level of lncRNA PVT1 expression was selected for subsequent experiments. We then proceeded to examine interaction among lncRNA PVT1, FSCN1, and miR‐145. The effect of lncRNA PVT1 on viability, migration, invasion, apoptosis, and tumorigenesis of transfected cells was examined with gain‐of‐function and loss‐of‐function experiments. We observed that lncRNA PVT1 was robustly induced in EC. lncRNA PVT1 could bind to miR‐145 and regulate its expression, and FSCN1 is a target gene of miR‐145. Overexpression of miR‐145 or silencing of lncRNA PVT1 was revealed to suppress cell viability, migration, and invasion abilities, while also stimulating cell apoptosis. Furthermore, our in vivo results showed that overexpression of miR‐145 or silencing of lncRNA PVT1 resulted in decreased tumor growth in nude mice. In conclusion, our research reveals that down‐regulation of lncRNA PVT1 could potentially promote expression of miR‐145 to repress cell migration and invasion, and promote cell apoptosis through the inhibition of FSCN1. This highlights the potential of lncRNA PVT1 as a therapeutic target for EC treatment.

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The tumour microenvironment (TME) plays a pivotal role in tumour fate determination. The TME acts together with the genetic material of tumour cells to determine their initiation, metastasis and drug resistance. Stromal cells in the TME promote the growth and metastasis of tumour cells by secreting soluble molecules or exosomes. The abnormal microenvironment reduces immune surveillance and tumour killing. The TME causes low anti‐tumour drug penetration and reactivity and high drug resistance. Tumour angiogenesis and microenvironmental hypoxia limit the drug concentration within the TME and enhance the stemness of tumour cells. Therefore, modifying the TME to effectively attack tumour cells could represent a comprehensive and effective anti‐tumour strategy. Normal cells, such as stem cells and immune cells, can penetrate and disrupt the abnormal TME. Reconstruction of the TME with healthy cells is an exciting new direction for tumour treatment. We will elaborate on the mechanism of the TME to support tumours and the current cell therapies for targeting tumours and the TME—such as immune cell therapies, haematopoietic stem cell (HSC) transplantation therapies, mesenchymal stem cell (MSC) transfer and embryonic stem cell‐based microenvironment therapies—to provide novel ideas for producing breakthroughs in tumour therapy strategies.

MicroRNAs (miRNA) play an important role in tumorigenesis, proliferation, and differentiation. Altered miRNA expression in cancer indicates that miRNAs can function as tumor suppressors or oncogenes. MiR-449c downregulation in non-small cell lung cancer (NSCLC) compared with normal lung tissues was investigated in this study. NSCLC cell proliferation and invasion assays indicate that transfection of miR-449c expression plasmid inhibits the proliferation and invasion ability of NCI-H23 and NCI-H838 cells. In addition, miR-449c overexpression could suppress tumor growth in vivo. Morever, c-Myc was identified as a direct target gene of miR-449c. These findings clearly suggest that miR-449c downregulation and c-Myc amplification may be involved in the development of NSCLC.