目的 探讨丰富生存环境(EE)对肿瘤抑制作用及可能机制.方法 EE饲养环境为12只以上小鼠置大空间笼饲养,笼内设有用于小鼠探索、学习和运动的玩具.小鼠置EE环境饲养3周后,皮下接种B16F10恶性黑色素瘤细胞或Panc02胰腺癌细胞,置原环境继续饲养,比较EE组和常规环境(SE)饲养组小鼠的成瘤率和瘤重.APC Min/+基因突变小鼠3周龄起分别置EE和SE环境饲养,20周龄时处死小鼠,比较两组小鼠小肠腺瘤数量.实验还采用Agilent小鼠全基因组44K表达谱芯片对Panc02胰腺癌细胞移植瘤组织进行基因表达差异分析.结果 与SE饲养比较,EE饲养对B16F10恶性黑色素瘤和Panc02胰腺癌皮下瘤的生长均有显著的抑制作用,抑瘤率分别为43.0％ (P ＜0.05)和58.2％(P＜0.01);EE对APCMin/+小鼠肠道腺瘤的生成也具有明显的抑制作用(P＜0.05).Panc02胰腺癌细胞移植瘤表达谱芯片结果的KEGG分析显示,有2倍以上表达差异的基因通路富集于细胞粘附和线粒体功能,并与神经退行性疾病和心脏疾病相关基因有交集.结论 EE对肿瘤的发生发展具有广泛的抑制作用,其对肿瘤细胞内线粒体功能的影响及其生物学意义值得深入研究.

Psycho-social stress has been suggested to influence the development of cancer, but it remains poorly defined with regard to pancreatic cancer, a lethal malignancy with few effective treatment modalities. In this study, we sought to investigate the impacts of enriched environment (EE) housing, a rodent model of "eustress", on the growth of mouse pancreatic cancer and to explore the potential underlying mechanisms through gene expression profiling. The EE mice showed significantly reduced tumor weights in both subcutaneous (53%) and orthotopic (41%) models, while each single component of EE (inanimate stimulation, social stimulation or physical exercise) was not profound enough to achieve comparative anti-tumor effects as EE. The integrative transcriptomic and proteomic analysis revealed that in response to EE, a total of 129 genes in the tumors showed differential expression at both the mRNA and protein levels. The differentially expressed genes were mostly localized to the mitochondria and enriched in the citrate cycle and oxidative phosphorylation pathways. Interestingly, nearly all of the mitochondria-related genes were down-regulated by EE. Our data have provided experimental evidence in favor of the application of positive stress or of benign environmental stimulation in pancreatic cancer therapy.

Emerging evidence has suggested that leptin, an adipokine related to energy homeostasis, plays a role in cancer growth and metastasis. However, its impact on pancreatic cancer is rarely studied. In this study, we found that leptin's functional receptor Ob-Rb was expressed in pancreatic cancer cell lines. Treatment with leptin enhanced the migration and invasion of pancreatic cancer cells but did not affect the proliferation of human pancreatic cancer cells. Leptin up-regulated the expression of matrix metalloproteinase-13 (MMP-13) via the JAK2/STAT3 signaling pathway. The overexpression of leptin was shown to significantly promote tumor growth and lymph node metastasis in a subcutaneous model and an orthotopic model of human pancreatic cancer, respectively. Furthermore, in human pancreatic cancer tissues, the expression of Ob-Rb was positively correlated with the MMP-13 level. The increased expression of either Ob-Rb or MMP-13 was significantly associated with lymph node metastasis and tended to be associated with the TNM stage in patients with pancreatic cancer. Our findings suggest that leptin enhances the invasion of pancreatic cancer through the increase in MMP-13 production, and targeting the leptin/MMP-13 axis could be an attractive therapeutic strategy for pancreatic cancer.

Objectives: To characterize the mutation pattern of a hepatitis B virus (HBV) core protein (HBcAg) derived from hepatocellular carcinoma (HCC) and adjacent nontumor tissues. Methods: HBV core gene fragments (nt. 1901–2365) were amplified from 98 HBV-related HCC tissues and 33 adjacent nontumor tissues. The deduced amino acids (AAs) of the core gene were aligned with the prototype sequences of HBV genotypes B and C. Results: In total, there were 54 positions that showed polymorphism at the deduced AA level. The mutations were predominantly located in three major (codons 83–87, 95–104 and 130–135) and three minor (codons 21–38, 59–63 and 151–155) mutation-clustering regions (MCRs). The substitution rate in MCRs was significantly higher than in mutation-devoid regions (p < 0.001). The most frequently occurring mutations in rank were codon P130T (38.8%), I97L (37.8%) and S87G (23.5%). In addition, there were 7 patients that showed internal deletions in the middle of HBcAg with sizes ranging from 34 to 59 AAs. Unexpectedly, the core genes isolated from tumor tissues had fewer mutations compared with those isolated from adjacent nontumor tissues from the same patients (p < 0.05). Conclusions: Accumulation of naturally occurring mutations in certain restricted segments of HBcAg may be related to the development of HCC.

Objective:To explore the relationship between mutations at 1-90 amino acid(AA) in N terminal of hepatitis B virus X protein(HBx) and the occurrence of hepatocellular carcinoma(HCC).Methods:The HBV X gene sequences were analyzed by using PCR direct sequencing method in 48 HCC tissues and serum samples of 159 HCC patients and 144 chronic hepatitis patients.A case-control study was used to analyze the relationship between HBx mutation and tumorigenesis of HCC.Results:The N terminal mutation of HBx isolated from HCC tissues was located at 1-49 AA,while 50-90 AA were conserved regions.The average mutation rates in hypervariable and conserved regions were 4.1% and 0.46%,respectively.The serum detection results showed that frequency of HBx N terminal mutation was higher in HCC patients than in non-HCC control patients(2.2% vs 1.8%,P0.05).A mutation of Ala/Thr/Pro to Ser at codon 36 was significantly increased in HCC patients compared with hepatitis patients [10.1% vs 2.1%,P0.01;odds ratio(OR)=5.259,95% confidence interval of 1.499-18.444].A/T/P36S mutation occurred only in type C virus.Conclusion:Accumulation of the N terminal mutations in HBx was related with tumorigenesis of hepatocellular carcinoma.HBx A/T/P36S mutation increased the risk of developing HCC in patients infected with type C HBV.