Lung cancer is a malignancy with high morbidity and mortality worldwide. More evidences indicated that gut microbiome plays an important role in the carcinogenesis and progression of cancers by metabolism, inflammation and immune response. However, the study about the characterizations of gut microbiome in lung cancer is limited. In this study, the fecal samples were collected from 16 healthy individuals and 30 lung cancer patients who were divided into 3 groups based on different tumor biomarkers (cytokeratin 19 fragment, neuron specific enolase and carcinoembryonic antigen, respectively) and were analyzed using 16S rRNA gene amplicon sequencing. Each lung cancer group has characterized gut microbial community and presents an elimination, low-density, and loss of bacterial diversity microbial ecosystem compared to that of the healthy control. The microbiome structures in family and genera levels are more complex and significantly varied from each group presenting more different and special pathogen microbiome such as Enterobacteriaceae, Streptococcus, Prevotella, etc and fewer probiotic genera including Blautia, Coprococcus, Bifidobacterium and Lachnospiraceae. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and COG annotation demonstrated decreased abundance of some dominant metabolism-related pathways in the lung cancer. This study explores for the first time the features of gut microbiome in lung cancer patients and may provide new insight into the pathogenesis of lung cancer system, with the implication that gut microbiota may serve as a microbial marker and contribute to the derived metabolites, development and differentiation in lung cancer system.

Long non-coding RNA, urothelial cancer associated 1 (UCA1), is reported to play a critical role in progression of carcinogenesis. In the present study, we identified differential expression of UCA1 in colorectal cancer (CRC) and paired peritumoral tissues using gene expression microarray analyses. qPCR analysis confirmed that UCA1 was upregulated in CRC (p<0.001) and the expression of UCA1 was statistically correlated with lymph node metastasis (P=0.040), distant metastasis (P=0.043) and tumor stage (P=0.010). Kaplan-Meier analysis indicated that patients with high UCA1 expression had a poor prognosis. Moreover, multivariate analysis identified UCA1 overexpression as an independent predictor for CRC. We also found that knockdown of UCA1 significantly suppressed cell proliferation and metastasis in CRC cells. Flow cytometry assays showed UCA1 silencing induced G0/G1 growth arrest and apoptosis of CRC cells. To further investigate the regulatory mechanisms of UCA1, we identified that Ets-2 bound to the UCA1 core promoter using luciferase assays. Collectively, our findings suggested that UCA1 might be an important prognostic indicator in CRC and may be a potential target for diagnosis and gene therapy.

Abstract. Accumulating evidence reveals that long non-coding RNA (lncRNA) is essential for tumorigenesis and progression, but little is known about its roles and mechanisms in metastatic colorectal cancer (CRC). This study aimed to detect expression level and prognostic role of lncRNA-CTD903 in CRC patients, which was selected based on one microarray data. The effects on cell invasion, migration and proliferation were investigated after silencing or overexpression of CTD903 in CRC cell lines. We also observed the EMT (epithelial-mesenchymal transition) phenomenon and effect on cell adhesion. The associations between CTD903 and EMT markers, such as E-cadherin, N-cadherin, β-catenin, ZEB1, ZO-1, Snail, and Twist, were determined by western blotting. Our results showed lncRNA-CTD903 expression was strongly upregulated in 115 CRC patients, comparing to adjacent normal tissues. CTD903 was proven to be an independent predicted factor of favorable prognosis in CRC patients by using multivariate Cox proportional hazards model. After knockdown of CTD903 in RKO and SW480, both cell invasion and migration increased, and cells exhibited EMT-like appearance, along with reduced adhering ability. Moreover, overexpression of CTD903 in DLD1 and HCT116 reversed these phenotypes. Furthermore, downregulation of CTD903 enhanced Wnt/β-catenin activation and subsequently increased transcription factors (Twist and Snail) expression, along with increased mesenchymal marker Vimentin and decreased epithelial marker ZO-1 level, while overexpressed CTD903 confirmed these associations.In conclusion, this study shows that LncRNA-CTD903 acts as a tumor suppressor in CRC and can inhibit cell invasion and migration through repressing Wnt/β-catenin signaling, which plays important roles in EMT and CRC metastasis.

The study was aimed to investigate the relationship between hypermethylation of Syk gene and clinicopathological characteristics and long-term outcomes in colorectal cancer. The effect of Syk on cell proliferation and invasion ability was also assessed. Methylation and expression status of Syk were explored in CRC tissues and cell lines by MSP, qRT-PCR and western blot assay. The effects of Syk overexpression on tumorigenesis were studied by in vitro assay. The correlation between Syk methylation and clinical relevance in CRC patients was also analyzed. Syk methylation was found 48.6 % in CRC tissue samples and 57.1 % in cell lines, respectively. The loss of Syk expression could be restored by demethylation agent. Overexpression of Syk in CRC cell inhibited cell proliferation (p< 0.01) and invasion (p < 0.01). The methylation of Syk was significantly associated with histological grade (p = 0.002), lymph node status (p < 0.001) and TNM stage (p < 0.001). Five-year overall survival in methylated Syk group was significantly lower than that in unmethylated Syk group (59 vs. 80 %, p < 0.001). Multivariate analysis demonstrated that Syk methylation was an independent prognostic factor for overall survival. Syk is identified as a potential tumor suppressor in CRC progression. Syk methylation is correlated with poor overall survival, which acts as an independent prognostic indicator of CRC.

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