Molybdenum is a trace dietary element necessary for the survival of humans. Some molybdenum-bearing enzymes are involved in key metabolic activities in the human body (such as xanthine oxidase, aldehyde oxidase and sulfite oxidase). Many molybdenum-based compounds have been widely used in biomedical research. Especially, MoS 2 -nanomaterials have attracted more attention in cancer diagnosis and treatment recently because of their unique physical and chemical properties. MoS 2 can adsorb various biomolecules and drug molecules via covalent or non-covalent interactions because it is easy to modify and possess a high specific surface area, improving its tumor targeting and colloidal stability, as well as accuracy and sensitivity for detecting specific biomarkers. At the same time, in the near-infrared (NIR) window, MoS 2 has excellent optical absorption and prominent photothermal conversion efficiency, which can achieve NIR-based phototherapy and NIR-responsive controlled drug-release. Significantly, the modified MoS 2 -nanocomposite can specifically respond to the tumor microenvironment, leading to drug accumulation in the tumor site increased, reducing its side effects on non-cancerous tissues, and improved therapeutic effect. In this review, we introduced the latest developments of MoS 2 -nanocomposites in cancer diagnosis and therapy, mainly focusing on biosensors, bioimaging, chemotherapy, phototherapy, microwave hyperthermia, and combination therapy. Furthermore, we also discuss the current challenges and prospects of MoS 2 -nanocomposites in cancer treatment.

Transforming growth factor-b (TGF-b) is involved in actin cytoskeleton reorganization and tumor progression. Fascin1, an actin-binding protein, increases cell invasiveness and motility in various transformed cells. To determine whether fascin1 is an important mediator of the tumor response to TGF-b, we applied the small interfering RNA (siRNA) technique to silence fascin1 in gastric cancer (GC) cells MKN45. Results showed that the effects of TGF-b1 on GC cells invasion and metastasis were mediated by tumor production of fascin1; furthermore, it was found that TGF-b1-induced fascin1 expression was suppressed by the specific inhibitors of JNK and ERK pathways, SP6001125 and PD98059, respectively, but not by transient transfection of Smad2 and Smad4 siRNA. Our data for the first time demonstrated that fascin1 is an important mediator of TGF-b1-induced invasion and metastasis of GC cells, which involves JNK and ERK signaling pathways.

Sirt3, a mitochondrial deacetylase, participates in the regulation of multiple cellular processes through its effect on protein acetylation. The objective of this study was to explore the role of Sirt3 in the mitochondrial autophagy (mitophagy), a process of the specific autophagic elimination of damaged mitochondria. We found that silencing of Sirt3 expression in human glioma cells by RNA interference blunted the hypoxia-induced the localization of LC3 on the mitochondria, and the degradation of mitochondria. These results suggest an important involvement of this protein deacetylase in the induction of mitophagy in cancer cells subjected to hypoxia. Further, we demonstrated that Sirt3 activated the hypoxia-induced mitophagy by increasing the interaction of VDAC1 with Parkin. In the cells subjected to hypoxia, inhibition of Sirt3-mediated mitophagy further decreased the mitochondrial membrane potential, and increased the accumulation of ROS that triggers the degradation of anti-apoptotic proteins Mcl-1 and survivin through the proteasomal pathway. Silencing of Sirt3 expression also promoted apoptosis, and enhanced the sensitivity of cancer cells to hypoxia. The regulatory role of Sirt3 in autophagy and apoptosis was also observed in human breast cancer cells. The results of the current study reveal Sirt3 as a novel regulator coupling mitophagy and apoptosis, two important cellular processes that determine cellular survival and death.

Chemokine-mediated activation of G protein-coupled receptors CXCR1/2 promotes tumor growth, invasion, inflammation and metastasis. Repertaxin, a CXCR1/2 small-molecule inhibitor, has been shown to attenuate many of these tumor-associated processes. The present study aimed to investigate the effects of repertaxin alone and in combination with 5-fluorouracil (5-FU) on the malignant behavior of gastric cancer and the potential mechanisms. Gastric cancer MKN45 cells were treated in vitro with repertaxin and 5-FU, either alone or in combination. MTT and colony formation assay were performed to assess proliferation. Cell cycle progression and apoptosis was completed by flow cytometry. Migration and invasion were also assessed by Transwell and wound-healing assay. Western blot analysis and quantitative RT-PCR were performed to determine expression of signaling molecules. MKN45 cells were also grown as xenografts in nude mice. Mice were treated with repertaxin and 5-FU, and tumor volume and weight, angiogenesis, proliferation and apoptosis were monitored. Combination of repertaxin and 5-FU inhibited MKN45 cell proliferation and increased apoptosis better than either agent alone. Similarly, enhanced effect of the combination was also observed in migration and invasion assays. The improved effect of repertaxin and 5-FU was also observed in vivo, as xenograft models treated with both compounds exhibited significantly decreased tumor volume and increased apoptosis. In conclusion, repertaxin inhibited malignant behavior of human gastric cancer MKN45 cells in vitro and in vivo and enhances efficacy of 5-fluorouracil. These data provide rationale that targeting CXCR1/2 with small molecule inhibitors may enhance chemotherapeutic efficacy for the treatment of gastric cancer.

Supervised learning methods are commonly applied in medical image analysis. However, the success of these approaches is highly dependent on the availability of large manually detailed annotated dataset. Thus an automatic refined segmentation of whole-slide image (WSI) is significant to alleviate the annotation workload of pathologists. But most of the current ways can only output a rough prediction of lesion areas and consume much time in each slide. In this paper, we propose a fast and refined cancer regions segmentation framework v3_DCNN, which first preselects tumor regions using a classification model Inception-v3 and then employs a semantic segmentation model DCNN for refined segmentation. Our framework can generate a dense likelihood heatmap with the 1/8 side of original WSI in 11.5 minutes on the Camelyon16 dataset, which saves more than one hour for each WSI compared with the initial DCNN model. Experimental results show that our approach achieves a higher FROC score 83.5% with the champion’s method of Camelyon16 challenge 80.7%. Based on v3 DCNN model, we further automatically produce heatmap of WSI and extract polygons of lesion regions for doctors, which is very helpful for their pathological diagnosis, detailed annotation and thus contributes to developing a more powerful deep learning model.

Oncogenic activation of the mTOR signaling pathway occurs frequently in tumor cells and contributes to the devastating features of cancer, including breast cancer. mTOR inhibitors rapalogs are promising anticancer agents in clinical trials; however, rapalogs resistance remains an unresolved clinical challenge. Therefore, understanding the mechanisms by which cells become resistant to rapalogs may guide the development of successful mTOR-targeted cancer therapy. In this study, we found that eEF-2K, which is overexpressed in cancer cells and is required for survival of stressed cells, was involved in the negative-feedback activation of Akt and cytoprotective autophagy induction in breast cancer cells in response to mTOR inhibitors. Therefore, disruption of eEF-2K simultaneously abrogates the two critical resistance signaling pathways, sensitizing breast cancer cells to rapalogs. Importantly, we identified mitoxantrone, an admitted anticancer drug for a wide range of tumors, as a potential inhibitor of eEF-2K via a structure-based virtual screening strategy. We further demonstrated that mitoxantrone binds to eEF-2K and inhibits its activity, and the combination treatment of mitoxantrone and mTOR inhibitor resulted in significant synergistic cytotoxicity in breast cancer. In conclusion, we report that eEF-2K contributes to the activation of resistance signaling pathways of mTOR inhibitor, suggesting a novel strategy to enhance mTOR-targeted cancer therapy through combining mitoxantrone, an eEF-2K inhibitor.

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CXCR1 is a member of the chemokine receptor family, which was reported to play an important role in several cancers. The present study investigated the influence of CXCR1 stable knockdown or overexpression on the malignant behavior of gastric cancer cells in vitro and in vivo and the potential mechanisms. MKN45 and BGC823 cells were stably transfected with plasmid pYr-1.1-CXCR1-shRNA (knockdown) and pIRES2-ZsGreen1-CXCR1 (overexpression), respectively. Malignant behavior was evaluated in vitro for changes in proliferation by MTT and colony forming assays; cell cycle and apoptosis by flow cytometry; and migration and invasion using transwell and wound-healing assays. Proliferation, cell cycle, apoptosis, migration and invasion-related signaling molecule expression were measured by real-time RT-PCR and western blot analysis. CXCR1 knockdown and overexpressing xenografts were monitored for in vivo tumor growth. Stable knockdown of CXCR1 inhibited MKN45 cell proliferation, migration and invasion, but were reversed in BGC823 cells stably overexpressing CXCR1. In addition, MKN45 cells stably transfected with CXCR1 shRNA inhibited AKT and ERK1/2 phosphorylation, protein expression of cyclin D1, EGFR, VEGF, MMP-9, MMP-2 and Bcl-2, and increased protein expression of Bax and E-cadherin (all P<0.05). In vivo CXCR1-shRNA-MKN45 cells transplanted into nude mice formed smaller tumors than non-transfected or scrambled-shRNA cells (both P<0.05). In contrast BGC823 cells overexpressing CXCR1 formed larger tumors in mice than cells carrying an empty expression plasmid or non-transfected cells (both P<0.05). CXCR1 promoted gastric cancer cell proliferation, migration and invasion. The present study provides preclinical data to support CXCR1 as a novel therapeutic target for gastric cancer.