Phosphoinositide 3-kinase (PI3K) pathway exerts its effects through Akt, its downstream target molecule, and thereby regulates various cell functions including cell proliferation, cell transformation, apoptosis, tumor growth, and angiogenesis. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has been implicated in regulating cell survival signaling through the PI3K/Akt pathway. However, the mechanism by PI3K/PTEN signaling regulates angiogenesis and tumor growth in vivo remains to be elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in tumor angiogenesis. The effect of PTEN on VEGF-mediated signal in pancreatic cancer is unknown. This study aimed to determine the effect of PTEN on both the expression of VEGF and angiogenesis. Toward that end, we used the siRNA knockdown method to specifically define the role of PTEN in the expression of VEGF and angiogenesis. We found that siRNA-mediated inhibition of PTEN gene expression in pancreatic cancer cells increase their VEGF secretion, up-modulated the proliferation, and migration of co-cultured vascular endothelial cell and enhanced tubule formation by HUVEC. In addition, PTEN modulated VEGF-mediated signaling and affected tumor angiogenesis through PI3K/Akt/VEGF/eNOS pathway.

Background: The tumour suppressor phosphatase and tensin homolog (PTEN) is an important negative regulator of cell-survival signaling. To evaluate the correlation between PTEN expression and clinicopathological characteristics of colorectal cancer patients with and without liver metastases, we investigated PTEN expression in primary colorectal cancer and colorectal cancer liver metastases.

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Purpose: The prognosis of patients with esophageal cancer remains poor, and the classification of tumor node metastasis has proven insufficient to predict patient prognosis. Therefore, novel predictive markers of esophageal cancer prognosis are needed. Notch receptors and their ligands have been reported to be upregulated in cervical, lung, colon, renal, and pancreatic cancers, but NOTCH1 expression has not been studied in esophageal cancer. Methods: Expression of NOTCH1 was quantified by real-time reverse transcription-polymerase chain reaction in 55 primary esophageal squamous cell carcinomas (ESCCs) and their paired normal esophageal mucosa. We then examined the correlations between NOTCH1 expression, clinicopathological factors, and prognosis in patients with ESCC. Results: The probability of overall survival was significantly lower for patients with high NOTCH1 expression (p = 0.0028; log-rank test). Overexpression of NOTCH1 was identified as a significant and independent prognostic factor (p = 0.0061) in patients who had undergone surgical treatment for ESCCs. The hazard ratio for predicting early death was 4.298 (95% confidence interval 1.515-12.195) for high versus low NOTCH1 expression. Conclusions: Our data indicate that NOTCH1 may be a candidate molecular prognostic marker and a molecular target for the development of an effective therapeutic intervention for patients with ESCC.