FBW7 functions as a tumor suppressor by targeting oncoproteins for degradation. Our previous study found FBW7 was low expressed in pancreatic cancer due to sustained activation of Ras-Raf-MEK-ERK pathway, which destabilized FBW7 by phosphorylating at Thr205. MicroPET/CT imaging results revealed that FBW7 substantially decreased 18F-fluorodeoxyglucose uptake in xenograft tumors. Mechanistically, FBW7 inhibited glucose metabolism via c-Myc/TXNIP axis. But in these studies, we observed FBW7 down-regulated genes were widely involved in redox reaction and lipid metabolism. Here we reanalyzed previous gene expression profiling and conducted targeted cell metabolites analysis. Results revealed that FBW7 regulated lipid peroxidation and promoted ferroptosis, a non-apoptotic form of cell death. Mechanistically, we found FBW7 inhibited the expression of stearoyl-CoA desaturase (SCD1) via inhibiting nuclear receptor subfamily 4 group A member 1 (NR4A1). SCD1 was reported to inhibit both ferroptosis and apoptosis, which was consistent with the function of FBW7 and NR4A1, another FBW7 down-regulated gene in the gene expression profiling. Moreover, FBW7 potentiated cytotoxic effect of gemcitabine via activating ferroptosis and apoptosis. Combination ferroptosis inducers and apoptosis activators could also significantly potentiated cytotoxic effect of gemcitabine in pancreatic cancer. Therefore, our findings might provide new strategies for the comprehensive treatment of pancreatic cancer.

Ferroptosis is a recently defined, non‐apoptotic, regulated cell death (RCD) process that comprises abnormal metabolism of cellular lipid oxides catalysed by iron ions or iron‐containing enzymes. In this process, a variety of inducers destroy the cell redox balance and produce a large number of lipid peroxidation products, eventually triggering cell death. However, in terms of morphology, biochemistry and genetics, ferroptosis is quite different from apoptosis, necrosis, autophagy‐dependent cell death and other RCD processes. A growing number of studies suggest that the relationship between ferroptosis and cancer is extremely complicated and that ferroptosis promises to be a novel approach for the cancer treatment. This article primarily focuses on the mechanism of ferroptosis and discusses the potential application of ferroptosis in cancer therapy.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, with a minimal difference between its incidence rate and mortality rate. Advances in oncology over the past several decades have dramatically improved the overall survival of patients with multiple cancers due to the implementation of new techniques in early diagnosis, therapeutic drugs, and personalized therapy. However, pancreatic cancers remain recalcitrant, with a 5-year relative survival rate of <9%. The lack of measures for early diagnosis, strong resistance to chemotherapy, ineffective adjuvant chemotherapy and the unavailability of molecularly targeted therapy are responsible for the high mortality rate of this notorious disease. Genetically, PDAC progresses as a complex result of the activation of oncogenes and inactivation of tumor suppressors. Although next-generation sequencing has identified numerous new genetic alterations, their clinical implications remain unknown. Classically, oncogenic mutations in genes such as KRAS and loss-offunction mutations in tumor suppressors, such as TP53, CDNK2A, DPC4/SMAD4, and BRCA2, are frequently observed in PDAC. Currently, research on these key driver genes is still the main focus. Therefore, studies assessing the functions of these genes and their potential clinical implications are of paramount importance. In this review, we summarize the biological function of key driver genes and pharmaceutical targets in PDAC. In addition, we conclude the results of molecularly targeted therapies in clinical trials and discuss how to utilize these genetic alterations in further clinical practice.

Abstract. miR-200a suppresses tumor development and progression; however, its role in tumor growth and metastasis of hepatocellular carcinoma (HCC) and the underlying mechanism have not been elucidated. In the present study, we identified that miR-200a was markedly downregulated in HCC and exerted suppressive effects on tumor cell growth and metastasis. We identified that miR-200a suppressed tumor growth and metastasis by directly targeting MACC1. In addition, HCC patients with low miR-200a expression had significantly worse prognosis than those with high expression of miR-200a. These findings suggest that miR200a may be recognized as a novel potential biomarker to predict the survival of patients with HCCs following liver transplantation.

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Objectives: Accumulated evidence suggests that Pin1 contributes to oncogenesis of diverse cancers. However, the underlying mechanism of oncogenic function of Pin1 in PDAC requires further exploration. Materials and Methods: IHC was performed using PDAC tissues. Western blot, PCR, immunofluorescence and transwell were performed using cell lines. GSEA were applied for possible downstream pathways. ChIP assay and dual luciferase were used for assessment of transcriptional activity. Results: Both Pin1 and IL-18 levels are increased in primary PDAC tissues and that their levels are positively correlated. High expression of IL-18 is a predictor of poor prognoses. Pin1 promoted pancreatic cancer cell proliferation and motility by increasing IL-18 expression, while Pin1 knockdown also inhibited the tumour-promoting effect of IL-18. Both Pin1 and IL-18 could enhance the NFκB activity in pancreatic cancer cells. When bound to the p65 protein, Pin1 promoted p65 phosphorylation and its nuclear translocation. In the nucleus, Pin1 and p65 simultaneously bound to the IL-18 promoter and enhanced IL-18 transcription. In addition, recruitment of p65 to the IL-18 promoter was decreased in Pin1-silenced cells. Conclusions: Our study improves the understanding of Pin1 in tumour-promoting inflammation in PDAC, which is a hallmark of cancer; Pin1 interacted with p65 in PDAC and enhanced NF-κB signalling and downstream transcriptional activation of IL-18, with increased IL-18 continuously activating NF-κB signalling, which then forms a positive feedback loop.

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Methylthioadenosine phosphorylase (MTAP) is a key enzyme associated with the salvage of methionine and adenine that is deficient in 20% to 30% of pancreatic cancer. Our previous study revealed that MTAP deficiency indicates a poor prognosis for patients with pancreatic ductal adenocarcinoma (PDAC). In this study, bioinformatics analysis of The Cancer Genome Atlas (TCGA) data indicated that PDACs with MTAP deficiency display a signature of elevated glycolysis. Metabolomics studies showed that that MTAP deletion–mediated metabolic reprogramming enhanced glycolysis and de novo purine synthesis in pancreatic cancer cells. Western blot analysis revealed that MTAP knockout stabilized hypoxia-inducible factor 1α (HIF1α) protein via posttranslational phosphorylation. RIO kinase 1 (RIOK1), a downstream kinase upregulated in MTAP-deficient cells, interacted with and phosphorylated HIF1α to regulate its stability. In vitro experiments demonstrated that the glycolysis inhibitor 2-deoxy-d-glucose (2-DG) and the de novo purine synthesis inhibitor l-alanosine synergized to kill MTAP-deficient pancreatic cancer cells. Collectively, these results reveal that MTAP deficiency drives pancreatic cancer progression by inducing metabolic reprogramming, providing a novel target and therapeutic strategy for treating MTAP-deficient disease. Significance: This study demonstrates that MTAP status impacts glucose and purine metabolism, thus identifying multiple novel treatment options against MTAP-deficient pancreatic cancer.