Downregulation of Notch Signaling in Kras-Induced Gastric Metaplasia

EGCG inhibits growth of tumoral lesions on lip and tongue of K-Ras transgenic mice through the Notch pathway

Epigallocatechin-3-gallate (EGCG), the main active ingredient of green tea, exhibits low toxic side effect and versatile bioactivities, and its anti-cancer effect has been extensively studied. Most of the studies used cancer cell lines and xenograft models. However, whether EGCG can prevent tumor onset after cancer-associated mutations occur is still controversial. In the present study, Krt14-cre/ERT-Kras transgenic mice were developed and the expression of K-RasG12D was induced by tamoxifen. Two weeks after induction, the K-Ras mutant mice developed exophytic tumoral lesions on the lips and tongues, with significant activation of Notch signaling pathway. Administration of EGCG effectively delayed the time of appearance, decreased the size and weight of tumoral lesions, relieved heterotypic hyperplasia of tumoral lesions, and prolonged the life of the mice. The Notch signaling pathway was significantly inhibited by EGCG in the tumoral lesions. Furthermore, EGCG significantly induced cell apoptosis and inhibited the proliferation of tongue cancer cells by blocking the activation of Notch signaling pathway. Taken together, these results indicate EGCG as an effective chemotherapeutic agent for tongue cancer by targeting Notch pathway.

Expression Analysis of MIST1 and EMT Markers in Primary Tumor Samples Points to MIST1 as a Biomarker of Cervical Cancer

Background

Mist1 is a basic transcription factor, which plays an important role in the development of multiple organs, and may also regulate tumor progression by mediating epithelial-mesenchymal transformation. However, there is lack of research on its role of squamous cell carcinoma, especially in cervical squamous cell carcinoma.

Methods

Bioinformatic methods were used to analyze gene expression, correlation, and patient survival according to the TCGA database. Thirty pairs of cancer tissues and distal cancer tissues from cervical cancer patients who received radical surgery were enrolled in the study. The expression of Mist1 was analyzed using Western blot. Furthermore, the potential associations among Mist1 expression, EMT biomarkers and various clinicopathological characteristics were investigated. All statistical tests employed in this study were two-sided, and P values <0.05 were deemed statistically significant.

Results

Overall survival data were obtained from TCGA-CESC dataset, containing 3 control samples and 305 tumor samples. The expression of Mist1 was significantly higher in primary tumor than in normal tissues (P<0.001). The samples were divided into a low Mist1 expression group (n=144) and a high Mist1 expression group (n=146) according to the median expression level. Kaplan–Meier survival analysis revealed that high expression of Mist1 was significantly correlated with poor overall survival (P=0.032). We further explored the relationships between Mist1 and EMT. Among the 30 primary cervical cancer specimens investigated, the difference in Mist1 expressed statuses between cervical cancer tissues and distal noncancerous cervical tissues was significant (P=0.001). And the epithelial cell marker E-cadherin was downregulated in Mist1 overexpressed cervical cancer cells; however, the mesenchymal marker N-Cadherin and Twist was upregulated.

Conclusion

Our study found that Mist1 seemed to play the role of oncogene in cervical squamous cell carcinoma and could be a potential biomarker.

Loss of HES-1 Expression Predicts a Poor Prognosis for Small Intestinal Adenocarcinoma Patients

Objective: Hairy and enhancer of split-1 (HES-1), which is a downstream target of the Notch signaling pathway, has been linked to KRAS mutations. HES-1 has been proposed as harboring oncogenic activity in colorectal cancer but has not been investigated in adenocarcinoma of the small intestine, where the drivers of oncogenesis are not as well-understood. Materials and Methods: To investigate the clinicopathologic and prognostic implications of HES-1, HES-1 immunohistochemical expression was analyzed in digital images along with clinicopathological variables, including survival and KRAS genotype, in 185 small intestinal adenocarcinomas. Results: The loss of HES-1 expression (HES-1^Loss) was observed in 38.4% (71/185) of the patients, and was associated with higher pT category (P = 0.018), pancreatic invasion (P = 0.005), high grade (P = 0.043), and non-tubular histology (P = 0.004). Specifically, in tumors with mutant KRAS (KRAS ^MT), HES-1^Loss was related to proximal location (P = 0.024), high T and N categories (P = 0.005 and 0.047, respectively), and pancreatic invasion (P = 0.004). Patients with HES-1^Loss showed worse overall survival compared to those with intact HES-1 (HES-1^Intact) (P = 0.013). Patients with HES-1^Loss/KRAS ^MT (median, 17.3 months) had significantly worse outcomes than those with HES-1^Intact/KRAS ^WT (39.9 months), HES-1^Intact/KRAS ^MT (47.6 month), and HES-1^Loss/KRAS ^WT (36.2 months; P = 0.010). By multivariate analysis, HES-1^Loss (hazard ratio = 1.55, 95% confidence interval (CI), 1.07-2.26; P = 0.022) remained an independent prognostic factor. Conclusion: HES-1expression can be used as a potential prognostic marker and may aid in the management of patients with small intestinal adenocarcinomas.