miR-147b mediated suppression of DUSP8 promotes lung cancer progression

Impact of C-FOS/C-JUN Transcriptional Factors Co-Expression in Non-small Cell Lung Carcinoma

Background/Aim

Significant transcription factors - including c-Fos (gene locus: 14q24.3) and c-Jun (gene locus: 1p32-p31) - regulate cell homeostasis preventing abnormal signal transduction to nucleus. Their over-activation seems to be associated with an aggressive phenotype in non-small cell lung carcinomas (NSCLCs). In the current study, our aim was to co-analyze c-FOS/c-JUN protein expression in a series of NSCLCs correlating them to the corresponding clinico-pathological features.

Materials and Methods

A set of fifty (n=50) paraffin embedded NSCLC tissue sections were selected comprising of adenocarcinomas (n=25) and squamous cell carcinomas (n=25), respectively. Immunocytochemistry (IHC) for the c-FOS/c-JUN markers was implemented. Digital image analysis (DIA) was also performed for evaluating objectively the corresponding immunostaining intensity levels of the examined proteins.

Results

All the examined tissue samples expressed the markers in different protein levels. High staining intensity levels were detected in 34/50 (68%) and 24/50 (48%), respectively. C-FOS over expression was statistically significant correlated to stage (p=0.033), whereas C-JUN over expression was associated with NSCLC histotype (p=0.05) and with maximum tumor diameter (p=0.046).

Conclusion

C-FOS/C-JUN co- over activation is observed frequently in NSCLC, playing potentially a central role in the aggressiveness of the malignancy's phenotype (advanced stage, increased metastatic potential). Development and implementation of novel agents that target these transcription factors is a promising approach for applying targeted therapeutic strategies in NSCC patients based on specific genetic signatures and protein profiles.

DUSP8-attenuated ERK1/2 signaling mediates lipogenesis and steroidogenesis in chicken granulosa cells

The lipogenesis and steroidogenesis of granulosa cells are crucial during follicular development, yet it remains unclear whether dual-specificity phosphatase 8 (DUSP8) is involved. In this study, the specific role of DUSP8 in lipogenesis and steroidogenesis was investigated through culturing chicken granulosa cells in vitro. The results revealed that the expression levels of adipogenic genes were elevated after DUSP8 overexpression and reduced after knockdown. The same was observed for lipid deposition in granulosa cells. Meanwhile, the steroidogenic gene expression and progesterone synthesis were promoted after DUSP8 overexpression and inhibited after knockdown. In addition, we also found that DUSP8 blocked the phosphorylation of extracellular regulatory kinase 1/2 (ERK1/2). Based on the previous results that activated ERK1/2 signaling inhibited lipid deposition and progesterone synthesis in chicken granulosa cells, we demonstrated that DUSP8 promoted lipid deposition and progesterone synthesis through mediating the ERK1/2 signaling pathway. The results will improve our understanding of the molecular regulatory mechanisms regarding lipid metabolism and progesterone synthesis in chicken granulosa cells.

Potential AhR-independent mechanisms of 2,3,7,8-Tetrachlorodibenzo-p-dioxin inhibition of human glioblastoma A172 cells migration

The toxicity of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is generally believed to be mediated by aryl hydrocarbon receptor (AhR), but some evidence suggests that the effects of TCDD can also be produced through AhR-independent mechanisms. In previous experiments, we found that mainly AhR-dependent mechanism was involved in the migration inhibition of glioblastoma U87 cells by TCDD. Due to the heterogeneity of glioblastomas, not all tumor cells have significant AhR expression. The effects and mechanisms of TCDD on the migration of glioblastomas with low AhR expression are still unclear. We employed a glioblastoma cell line A172 with low AhR expression as a model, using wound healing and Transwell® assay to detect the effect of TCDD on cell migration. We found that TCDD can inhibit the migration of A172 cells without activating AhR signaling pathway. Further, after being pre-treated with AhR antagonist CH223191, the inhibition of TCDD on A172 cells migration was not changed, indicating that the effect of TCDD on A172 cells is not dependent on AhR activation. By transcriptome sequencing analysis, we propose dysregulation of the expression of certain migration-related genes, such as IL6, IL1B, CXCL8, FOS, SYK, and PTGS2 involved in cytokines, MAPK, NF-κB, and IL-17 signaling pathways, as potential AhR-independent mechanisms that mediate the inhibition of TCDD migration in A172 cells.