miR-612 Enhances RSL3-Induced Ferroptosis of Hepatocellular Carcinoma Cells via Mevalonate Pathway.

Background: MicroRNA-612 (miR-612) has been proven to suppress the formation of invadopodia and inhibit hepatocellular carcinoma (HCC) metastasis by hydroxyacyl-CoA dehydrogenase alpha subunit (HADHA)-mediated lipid reprogramming. However, its biological roles in HCC cell ferroptosis remain unclear. Methods and Results: In this study, we found that HCC cells with high metastatic potential were more resistant to ferroptosis, indicating that ferroptosis is related to HCC metastasis. The levels of lipid reactive oxygen species (ROS) were found to be much lower in HCC cells with high metastatic potential by flow cytometry (FCM). We used HCC cells with miR-612 overexpression/knockout and HADHA overexpression/knockdown to test cell viability after stimulation with RSL3. HCC cells overexpressing miR-612 were more sensitive to ferroptosis, and miR-612 could increase lipid ROS levels. Furthermore, colony formation assays and Transwell assays showed that miR-612 could inhibit the proliferation and metastasis of HCC cells by promoting ferroptosis. We next confirmed that miR-612 influenced HCC cell ferroptosis by regulating HADHA. HADHA could upregulate the expression of key enzymes in the mevalonate (MVA) pathway. HADHA overexpression upregulated the expression of CoQ10 and decreased polyunsaturated fatty acid (PUFA) levels and lipid peroxide abundance. miR-612 also suppressed HCC cell proliferation and metastasis by enhancing RSL3- and lovastatin-induced ferroptosis in vivo. Conclusion: Overall, miR-612 promotes ferroptosis in HCC cells and affects HCC proliferation and metastasis by downregulating CoQ10 and increasing cellular PUFA levels and lipid peroxides via the HADHA-mediated MVA pathway.

AMD1 upregulates hepatocellular carcinoma cells stemness by FTO mediated mRNA demethylation.

BACKGROUND: S-adenosylmethionine decarboxylase proenzyme (AMD1) is a key enzyme involved in the synthesis of spermine (SPM) and spermidine (SPD), which are associated with multifarious cellular processes. It is also found to be an oncogene in multiple cancers and a potential target for tumor therapy. Nevertheless, the role AMD1 plays in hepatocellular carcinoma (HCC) is still unknown. METHODS: HCC samples were applied to detect AMD1 expression and evaluate its associations with clinicopathological features and prognosis. Subcutaneous and orthotopic tumor mouse models were constructed to analyze the proliferation and metastasis of HCC cells after AMD1 knockdown or overexpression. Drug sensitive and tumor sphere assay were performed to investigate the effect of AMD1 on HCC cells stemness. Real-time quantitative PCR (qRT-PCR), western blot, immunohistochemical (IHC) and m6A-RNA immunoprecipitation (Me-RIP) sequencing/qPCR were applied to explore the potential mechanisms of AMD1 in HCC. Furthermore, immunofluorescence, co-IP (Co-IP) assays, and mass spectrometric (MS) analyses were performed to verify the proteins interacting with AMD1. RESULTS: AMD1 was enriched in human HCC tissues and suggested a poor prognosis. High AMD1 level could promote SRY-box transcription factor 2 (SOX2), Kruppel like factor 4 (KLF4), and NANOG expression of HCC cells through obesity-associated protein (FTO)-mediated mRNA demethylation. Mechanistically, high AMD1 expression increased the levels of SPD in HCC cells, which could modify the scaffold protein, Ras GTPase-activating-like protein 1 (IQGAP1) and enhance the interaction between IQGAP1 and FTO. This interaction could enhance the phosphorylation and decrease the ubiquitination of FTO. CONCLUSIONS: AMD1 could stabilize the interaction of IQGAP1 with FTO, which then promotes FTO expression and increases HCC stemness. AMD1 shows prospects as a prognostic predictor and a therapeutic target for HCC.

miR-296-5p suppresses stem cell potency of hepatocellular carcinoma cells via regulating Brg1/Sall4 axis.

Epithelial-mesenchymal transition (EMT), a pivotal event during cancer progression such as relapse and metastasis, is positively correlated with the stemness potency of tumor cells. Our previous study showed that miR-296-5p attenuated EMT program of hepatocellular carcinoma cells (HCC) through NRG1/ERBB2/ERBB3 signaling. In the present study, we uncovered that miR-296-5p was able to inhibit the stemness potency of HCC by decreasing the number and size of tumorspheres, downregulating the expression of CSC biomarkers and hampering the ability of tumorigenesis in NOD/SCID mice. Brahma-related gene-1 (Brg1), as the target protein of miR-296-5p detected by bioinformatics methods, activates a series of downstream cascades through directly binding to Sall4 promoter and enhancing Sall4 transcription. Importantly, the higher expressions of Brg1 and Sall4 in tumor tissues of HCC patients suggest poorer prognoses after surgical extraction. In conclusion, miR-296-5p exerts an inhibitory effect on stemness potency of HCC cells via Brg1/Sall4 axis.

Effect of clinicopathologic features on survival of patients with thymic carcinomas and thymic neuroendocrine tumors: A population-based analysis.

BACKGROUND: Thymic carcinomas (TCs) and thymic neuroendocrine tumors (TNETs) are aggressive cancers with poor survival outcome and limited investigation. This study is to investigate clinicopathologic features on TC and TNET patients' prognosis of a large cohort. MATERIALS AND METHODS: The Surveillance, Epidemiology, and End Results database were used to identify a total of 362 TC and TNET patients with documented clinicopathologic features we investigated. The characteristics and overall survival of the TC and TNET patients were studied. RESULTS: Two hundred and forty TC and 122 TNET patients were identified. For the entire cohort of TC and TNET, histologic type (P < 0.001), tumor size (P = 0.015), Masaoka-Koga stage (P = 0.008), regional node positive (P = 0.004), surgery of primary site (P < 0.001), lymph node surgery (P = 0.013), and chemotherapy (P = 0.001) were considered as significant clinicopathologic features that could affect prognosis of TC and TNET patients in univariate analysis. More importantly, histologic type (P < 0.001), regional nodes positive (P = 0.03) and surgery of primary site (P < 0.001) were able to independently predict overall survival of those patients. In addition, for the cohort of TC, we found that regional nodes positive (P = 0.034) and surgery of primary site (P = 0.001) could be independent predictors of TC patients' survival. CONCLUSION: Regional nodes detection is essential for TC and TNET patients. Surgery of primary site is the preferred primary treatment for those patients.

Protective immunity elicited by measles vaccine exerts anti-tumor effects on measles virus hemagglutinin gene-modified cancer cells in a mouse model.

PURPOSE: Measles vaccine is widely used in China to prevent the measles virus (MV) infection. People immunized with measles vaccine can obtain long-term protective immunity. Measles virus surface glycoprotein hemagglutinin (H) can also induce MV-specific immune responses. However, little is known about whether the existence of the protective immune system against MV in the host can exert anti-tumor effects and whether the MV-H gene can serve as a therapeutic gene. METHODS: We first vaccinated mice with measles vaccine, then inoculated them with MV-H protein-expressing tumor cells and observed the rate of tumor formation. We also treated mice with H protein-expressing tumor cells with measles vaccine and assessed tumor size and overall survival. RESULTS: Active vaccination using measles vaccine not only protected mice from developing tumors, but also eradicated established tumors. Measles vaccine elicited H-specific IFN-γ, TNF-α and granzyme B-producing CD8+ T cells and increased cytotoxic T lymphocyte (CTL) activity specific for H antigen, which provided a strong therapeutic benefit against H protein-expressing tumors. In addition, measles vaccine decreased the population of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). CONCLUSIONS: Our study demonstrated that tumor cells expressing H protein could activate the immune memory response against MV, which exerted specific anti-tumor effects, and indicated that the MV-H gene can be used as a potential therapeutic gene for cancer gene therapy.

A novel strategy of EGFR­TKI combined chemotherapy in the treatment of human lung cancer with EGFR­sensitive mutation.

The discovery of epidermal growth factor receptor (EGFR)­sensitive mutations in non­small cell lung cancer (NSCLC) and the successful clinical application of EGFR tyrosine kinase inhibitors (TKIs) have changed the regimen of lung cancer therapy from traditional cytotoxic chemotherapy to molecular­targeted cancer therapy. However, the main limitation of EGFR­TKI therapy is the heterogeneity of lung cancer harboring EGFR­sensitive mutations. In addition, the synergistic effect of the administration of chemotherapy and EGFR­TKIs, combined with tumor heterogeneity, on NSCLC remains unclear. The present study aimed to investigate the optimal schedule for combined treatment with paclitaxel/gemcitabine and gefitinib in co­cultured NSCLC cell lines, in which PC9 cells were mixed with A549 cells at 0:1, 1:19, 1:3, 1:1, 3:1 and 1:0 ratios, and clarified the associated mechanisms. The mixed cells were used to simulate the tumor heterogeneity in the human cancer environment and to define the differential anti­proliferative effects of nine schedules of paclitaxel/gemcitabine and gefitinib, based on cell cycle distribution. We confirmed that gefitinib arrested PC9 cell growth, mainly at the G1 phase, at 24 h regardless of low or high concentration. After a 24­h culture in gefitinib­free medium, the cell cycle returned to its normal state. Paclitaxel and gemcitabine induced G2/M phase and S phase arrest at 72 h, respectively. The anti­proliferative effect of paclitaxel/gemcitabine followed by gefitinib resulted in the optimum anti­proliferative activity compared with the other seven schedules, which was not affected by tumor heterogeneity. Cell cycle­dependent synergism may contribute to this effect. Our results are in accordance with most of the existing clinical trials, and could provide a potential treatment option for patients with advanced NSCLC and for the ongoing clinical investigation of the sequential treatment of NSCLC.

Dexamethasone enhances programmed cell death 1 (PD-1) expression during T cell activation: an insight into the optimum application of glucocorticoids in anti-cancer therapy.

BACKGROUND: Programmed cell death 1 (PD-1) is a key cell-surface receptor of CD28 superfamily that triggers inhibitory pathways to attenuate T-cell responses and promote T-cell tolerance. As a crucial role in tumor immunity, PD-1 has been a focus of studies in anti-cancer therapy. It has been approved that tumors could exploit PD-1-dependent immune suppression for immune evasion. Considering the wide use of glucocorticoids (GCs) in anti-cancer therapy and their immunosuppressive effects, we explored whether GCs could influence the expression of PD-1. RESULTS: In our study, we used dexamethasone (DEX) as a model glucocorticoid and demonstrated that DEX could enhance PD-1 expression in a dose-dependent manner. The effects were completely inhibited by the glucocorticoid receptor (GR) antagonist mifepristone (RU486), indicating that the effect of DEX on PD-1 is mediated through GR. We further found the sensitivity to DEX-induced upregulation of PD-1 expression had a significant difference between different T cell subsets, with memory T cells more susceptible to this effect. We also showed that DEX could suppress T cell functions via inhibition of cytokines production such as IL-2, IFN-γ, TNF-α and induction of apoptosis of T cells. CONCLUSION: Our findings suggest a novel way by which DEX suppress the function of activated T lymphocytes by enhancing expression of PD-1 and provide an insight into the optimum clinical application of GCs.

A novel point mutation in exon 20 of EGFR showed sensitivity to erlotinib.

Mutations of epidermal growth factor receptor (EGFR) gene are good predictors of response to treatment with EGFR tyrosine kinase inhibitors (TKIs) for non-small cell lung cancer (NSCLC). It is well established that classic mutations, such as in-frame deletions in exon 19 and the point mutation L858R in exon 21, are associated with high sensitivity to EGFR TKIs. Though mutations in exon 20 are almost correlated with EGFR-TKIs resistance, the awareness that they might confer sensitivity to TKI treatment should be emphasized. Herein, we describe a novel mutation in exon 20 of EGFR in a Chinese male non-smoker, who was diagnosed with stage IV lung adenocarcinoma and characterized by the codon 769 point mutation GTG>GCG, which translates into alanine instead of valine (p.V769A). In this case, the patient showed a good clinical response to erlotinib after paclitaxel/cisplatin first-line and docetaxel second-line chemotherapies. Therefore, we suggest that this rare mutation (p.V769A) may be a sensitive EGFR mutation in NSCLC. The identification of novel EGFR mutations provides new predictive biomarkers for TKI treatment and is essential to the successful use of targeted therapies.