SMAC exhibits anti-tumor effects in ECA109 cells by regulating expression of inhibitor of apoptosis protein family.

BACKGROUND: The poor prognosis and rising incidence of esophageal cancer highlight the need for improved therapeutics that are essential prior to treatment. LCL161 is an SMAC (second mitochondrial activator of caspases) mimic and inhibitor of apoptosis protein (IAP) antagonist which exhibits anti-tumor effects and improves the chemical sensitivity of many cancers. AIM: To ascertain the effects and mechanisms of the SMAC analog LCL161 on esophageal cancer cells. METHODS: MTT assay and TUNEL assay were used to detect cell proliferation and apoptosis, respectively. Western blot analysis was used to study the molecular mechanisms of LCL161-induced death of ECA109 cells. RESULTS: LCL161 decreased ECA109 cell proliferation in dose- and time-dependent manner and induced apoptosis of ECA109 cells in a dose-dependent manner. Also, LCL161 induced a significant decrease in the expression of the XIAP and significant increase in the expression of Caspase-3. In addition, Bax increased significantly with increasing concentrations of LCL161, and the relative expression of Bax was significantly different between groups. CONCLUSION: These findings support the hypothesis that LCL161 can inhibit proliferation and induce apoptosis in esophageal cancer cells by regulating the expression of IAP family members, suggesting that it has potential to be an effective treatment for esophageal squamous cell carcinoma.

Alterations of fecal bacterial communities in patients with lung cancer.

Emerging evidence suggests the microbiome may affect a number of diseases, including lung cancer. However, the direct relationship between gut bacteria and lung cancer remains uncharacterized. In this study, we directly sequenced the hypervariable V1-V2 regions of the 16S rRNA gene in fecal samples from patients with lung cancer and healthy volunteers. Unweighted principal coordinate analysis (PCoA) revealed a clear difference in the bacterial community membership between the lung cancer group and the healthy control group. The lung cancer group had remarkably higher levels of Bacteroidetes, Fusobacteria, Cyanobacteria, Spirochaetes, and Lentisphaerae but dramatically lower levels of Firmicutes and Verrucomicrobia than the healthy control group (P < 0.05). Despite significant interindividual variation, eight predominant genera were significantly different between the two groups. The lung cancer group had higher levels of Bacteroides, Veillonella, and Fusobacterium but lower levels of Escherichia-Shigella, Kluyvera, Fecalibacterium, Enterobacter, and Dialister than the healthy control group (P < 0.05). Most notably, correlations between certain specific bacteria and serum inflammatory biomarkers were identified. Our findings demonstrated an altered bacterial community in patients with lung cancer, providing a significant step in understanding the relationship between gut bacteria and lung cancer. To our knowledge, this is the first study to evaluate the correlations between certain specific bacteria and inflammatory indicators. To better understand this relationship, further studies should investigate the underlying mechanisms of gut bacteria in lung cancer animal models.

Effect of spleen tyrosine kinase on nonsmall cell lung cancer.

AIM OF STUDY: To investigate the anti.tumor effect of spleen tyrosine kinase. (Syk) on the human nonsmall cell lung cancer cells in vitro and its mechanism. MATERIALS AND METHODS: In this study, we constructed a eukaryotic expression vector pcDNA3.1D/V5-His-TOPO/Syk and transfected it into human nonsmall cell lung cancer cells A549. Then, we not only analyzed the expression of Syk in transfected cells and its invasion but also the expression of matrix metalloproteinase-9 (MMP-9). RESULTS: The results showed that overexpressed Syk significantly inhibited A549 cell invasive ability by decreasing the expression of MMP-9. CONCLUSION: The overexpressed Syk plays an important role in tumor invasion and metastasis, and a negative role in human nonsmall cell lung cancer cells.

Inhibitory effects of syk transfection on lung cancer cell invasion.

OBJECTIVE: Spleen tyrosine kinase (Syk) is closely related to tumor invasion and metastasis, and has been shown to have potential inhibitory effects in tumors. In this study, we constructed a eukaryotic expression vector for Syk and analyzed its effects on invasive ability of the A549 non-small cell lung cancer cell line in vitro. METHODS: A fragment of Syk was obtained by RT-PCR from human lung cancer cells and cloned into the expression vector pLNCXSyk. After restriction endonuclease digestion, PCR and DNA sequencing confirmation, the recombinant Syk expression plasmid was transfected into A549 human lung cancer cells using lipofectamine protocols. After selection, the cells stably expressed Syk. Detection of Syk expression of the cells by RT-PCR, and invasive ability were examined. RESULTS: The eukaryotic expression plamid pLNCXSyk was constructed and expressed stably in the A549 human lung cancer cells. The RT-PCR results showed that Syk mRNA expression was upregulated significantly (P<0.05). Lower invasion through a basal membrane were apparent after transfection (P<0.05). CONCLUSIONS: A eukaryotic expression plasmid to cause Syk expression in lung cancer cells can obviously inhibit their invasive ability in vitro.