The expression and clinical significance of pSTAT3, VEGF and VEGF-C in pancreatic adenocarcinoma

Exploration of immune cell heterogeneity by single-cell RNA sequencing and identification of secretory leukocyte protease inhibitor as an oncogene in pancreatic cancer

Clinical outcomes remain unsatisfactory in patients with pancreatic cancer (PAC). In this study, through single-cell sequencing, we identified eight cell subpopulations in the tumor microenvironment (TME). Redimensional clustering of epithelial cells, myeloid cells, and cancer-associated fibroblasts (CAFs) revealed heterogeneity in the TME of PAC. Intercellular communication analysis showed strong direct interactions between matrix CAFs, inflammatory CAFs, and epithelial cells. Additionally, we found that the SPP1-associated pathway was activated in monocytes, whereas the vascular endothelial growth factor-associated pathway was activated in epithelial cells. These results improve the understanding of the TME of pancreatic cancer and provide a foundation for further studies on intratumoral heterogeneity. In addition, differentially expressed gene secretory leukocyte protease inhibitor (SLPI) was identified in pancreatic cancer, and functional experiments showed that SLPI had a strong impact on cell viability and apoptosis, which offers a potential therapy target for pancreatic cancer.

Unraveling the complexity of STAT3 in cancer: molecular understanding and drug discovery

Signal transducer and activator of transcription 3 (STAT3) is a transcriptional factor involved in almost all cancer hallmark features including tumor proliferation, metastasis, angiogenesis, immunosuppression, tumor inflammation, metabolism reprogramming, drug resistance, cancer stemness. Therefore, STAT3 has become a promising therapeutic target in a wide range of cancers. This review focuses on the up-to-date knowledge of STAT3 signaling in cancer. We summarize both the positive and negative modulators of STAT3 together with the cancer hallmarks involving activities regulated by STAT3 and highlight its extremely sophisticated regulation on immunosuppression in tumor microenvironment and metabolic reprogramming. Direct and indirect inhibitors of STAT3 in preclinical and clinical studies also have been summarized and discussed. Additionally, we highlight and propose new strategies of targeting STAT3 and STAT3-based combinations with established chemotherapy, targeted therapy, immunotherapy and combination therapy. These efforts may provide new perspectives for STAT3-based target therapy in cancer.

Novel Histopathological Biomarkers in Prostate Cancer: Implications and Perspectives

Prostate cancer (PCa) is the second most frequently diagnosed cancer in men. Despite the significant progress in cancer diagnosis and treatment over the last few years, the approach to disease detection and therapy still does not include histopathological biomarkers. The dissemination of PCa is strictly related to the creation of a premetastatic niche, which can be detected by altered levels of specific biomarkers. To date, the risk factors for biochemical recurrence include lymph node status, prostate-specific antigen (PSA), PSA density (PSAD), body mass index (BMI), pathological Gleason score, seminal vesicle invasion, extraprostatic extension, and intraductal carcinoma. In the future, biomarkers might represent another prognostic factor, as discussed in many studies. In this review, we focus on histopathological biomarkers (particularly CD169 macrophages, neuropilin-1, cofilin-1, interleukin-17, signal transducer and activator of transcription protein 3 (STAT3), LIM domain kinase 1 (LIMK1), CD15, AMACR, prostate-specific membrane antigen (PSMA), Appl1, Sortilin, Syndecan-1, and p63) and their potential application in decision making regarding the prognosis and treatment of PCa patients. We refer to studies that found a correlation between the levels of biomarkers and tumor characteristics as well as clinical outcomes. We also hypothesize about the potential use of histopathological markers as a target for novel immunotherapeutic drugs or targeted radionuclide therapy, which may be used as adjuvant therapy in the future.

Napabucasin plus nab-paclitaxel with gemcitabine versus nab-paclitaxel with gemcitabine in previously untreated metastatic pancreatic adenocarcinoma: an adaptive multicentre, randomised, open-label, phase 3, superiority trial

BACKGROUND

Compared with normal cells, tumour cells contain elevated levels of reactive oxygen species (ROS). Increased levels of the antioxidant protein NAD(P)H:quinone oxidoreductase 1 (NQO1) and phosphorylated signal transducer and activator of transcription 3 (pSTAT3) correlate negatively with the survival of patients with pancreatic cancer. Napabucasin is an investigational, orally administered ROS generator bioactivated by NQO1.

METHODS

In the open-label, phase 3 CanStem111P study (NCT02993731), adults with previously untreated metastatic pancreatic adenocarcinoma (mPDAC) were randomised (1:1) to napabucasin plus nab-paclitaxel with gemcitabine or nab-paclitaxel with gemcitabine alone. The primary endpoint was overall survival (OS). In exploratory analyses, OS was evaluated in the subgroup of patients with tumours positive for pSTAT3 (biomarker-positive).

FINDINGS

Between 30 January 2017 and 20 February 2019, a total of 1779 patients were screened across 165 study sites in Austria, Australia, Belgium, Canada, China, Czech Republic, France, Germany, Italy, Japan, Korea, Netherlands, Poland, Portugal, Russia, Singapore, Spain, Taiwan, Ukraine, and the US. Of the 565 and 569 patients randomised to the napabucasin and control treatment arms, respectively, 206 and 176 were biomarker-positive. Median (95% confidence interval [CI]) OS in the napabucasin and control treatment arms was 11.4 (10.5-12.2) and 11.7 (10.7-12.7) months, respectively (hazard ratio, 1.07; 95% CI, 0.93-1.23). Due to the lack of OS improvement in the napabucasin arm, CanStem111P was terminated due to futility. In the biomarker-positive subgroup, no difference between treatment arms was found for OS. Grade ≥3 adverse events were reported in 85.4% and 83.9% of napabucasin-treated and control-treated patients, respectively. The incidence of gastrointestinal-related grade ≥3 events was higher with napabucasin (diarrhoea: 11.6% vs 4.9%; abdominal pain: 10.0% vs 4.8%).

INTERPRETATION

Our findings suggested that although the addition of napabucasin to nab-paclitaxel with gemcitabine did not improve efficacy in patients with previously untreated mPDAC, the safety profile of napabucasin was consistent with previous reports. CanStem111P represents the largest cohort of patients with mPDAC administered nab-paclitaxel with gemcitabine in the clinical trial setting. Our data reinforce the value of nab-paclitaxel plus gemcitabine as a platform for novel therapeutics approaches in mPDAC.

FUNDING

The Sumitomo Pharma Oncology, Inc.

STAT3 Inhibitors: A Novel Insight for Anticancer Therapy of Pancreatic Cancer

The signal transducer and activator of transcription (STAT) is a family of intracellular cytoplasmic transcription factors involved in many biological functions in mammalian signal transduction. Among them, STAT3 is involved in cell proliferation, differentiation, apoptosis, and inflammatory responses. Despite the advances in the treatment of pancreatic cancer in the past decade, the prognosis for patients with pancreatic cancer remains poor. STAT3 has been shown to play a pro-cancer role in a variety of cancers, and inhibitors of STAT3 are used in pre-clinical and clinical studies. We reviewed the relationship between STAT3 and pancreatic cancer and the latest results on the use of STAT3 inhibitors in pancreatic cancer, with the aim of providing insights and ideas around STAT3 inhibitors for a new generation of chemotherapeutic modalities for pancreatic cancer.

Central Roles of STAT3-Mediated Signals in Onset and Development of Cancers: Tumorigenesis and Immunosurveillance

Since the time of Rudolf Virchow in the 19th century, it has been well-known that cancer-associated inflammation contributes to tumor initiation and progression. However, it remains unclear whether a collapse of the balance between the antitumor immune response via the immunological surveillance system and protumor immunity due to cancer-related inflammation is responsible for cancer malignancy. The majority of inflammatory signals affect tumorigenesis by activating signal transducer and activation of transcription 3 (STAT3) and nuclear factor-κB. Persistent STAT3 activation in malignant cancer cells mediates extremely widespread functions, including cell growth, survival, angiogenesis, and invasion and contributes to an increase in inflammation-associated tumorigenesis. In addition, intracellular STAT3 activation in immune cells causes suppressive effects on antitumor immunity and leads to the differentiation and mobilization of immature myeloid-derived cells and tumor-associated macrophages. In many cancer types, STAT3 does not directly rely on its activation by oncogenic mutations but has important oncogenic and malignant transformation-associated functions in both cancer and stromal cells in the tumor microenvironment (TME). We have reported a series of studies aiming towards understanding the molecular mechanisms underlying the proliferation of various types of tumors involving signal-transducing adaptor protein-2 as an adaptor molecule that modulates STAT3 activity, and we recently found that AT-rich interactive domain-containing protein 5a functions as an mRNA stabilizer that orchestrates an immunosuppressive TME in malignant mesenchymal tumors. In this review, we summarize recent advances in our understanding of the functional role of STAT3 in tumor progression and introduce novel molecular mechanisms of cancer development and malignant transformation involving STAT3 activation that we have identified to date. Finally, we discuss potential therapeutic strategies for cancer that target the signaling pathway to augment STAT3 activity.

ID1 marks the tumorigenesis of pancreatic ductal adenocarcinoma in mouse and human

Pancreatic Ductal Adenocarcinoma (PDAC) is a deadly disease that has an increasing death rate but no effective treatment to now. Although biological and immunological hallmarks of PDAC have been frequently reported recently, early detection and the particularly aggressive biological features are the major challenges remaining unclear. In the current study, we retrieved multiple scRNA-seq datasets and illustrated the genetic programs of PDAC development in genetically modified mouse models. Notably, the transcription levels of Id1 were elevated specifically along with the PDAC development. Pseudotime trajectory analysis revealed that Id1 was closely correlated with the malignancy of PDAC. The gene expression patterns of human PDAC cells were determined by the comparative analysis of the scRNA-seq data on human PDAC and normal pancreas tissues. ID1 levels in human PDAC cancer cells were dramatically increased compared to normal epithelial cells. ID1 deficiency in vitro significantly blunt the invasive tumor-formation related phenotypes. IPA analysis on the differentially expressed genes suggested that EIF2 signaling was the core pathway regulating the development of PDAC. Blocking EFI2 signaling remarkably decreased the expression of ID1 and attenuated the tumor-formation related phenotypes. These observations confirmed that ID1 was regulated by EIF2 signaling and was the critical determinator of PDAC development and progression. This study suggests that ID1 is a potential malignant biomarker of PDAC in both mouse models and human and detecting and targeting ID1 may be a promising strategy to treat or even rescue PDAC.

Silymarin (milk thistle extract) as a therapeutic agent in gastrointestinal cancer

Silymarin contains a group of closely-related flavonolignan compounds including silibinin, and is extracted from Silybum marianum species, also called milk thistle. Silymarin has been shown to protect the liver in both experimental models and clinical studies. The chemopreventive activity of silymarin has shown some efficacy against cancer both in vitro and in vivo. Silymarin can modulate apoptosis in vitro and survival in vivo, by interfering with the expression of cell cycle regulators and apoptosis-associated proteins. In addition to its anti-metastatic activity, silymarin has also been reported to exhibit anti-inflammatory activity. The chemoprotective effects of silymarin and silibinin (its major constituent) suggest they could be applied to reduce the side effects and increase the anti-cancer effects of chemotherapy and radiotherapy in various cancer types, especially in gastrointestinal cancers. This review examines the recent studies and summarizes the mechanistic pathways and down-stream targets of silymarin in the therapy of gastrointestinal cancer.

Computational STAT3 activity inference reveals its roles in the pancreatic tumor microenvironment

Transcription factor (TF) STAT3 contributes to pancreatic cancer progression through its regulatory roles in both tumor cells and the tumor microenvironment (TME). In this study, we performed a systematic analysis of all TFs in patient-derived gene expression datasets and confirmed STAT3 as a critical regulator in the pancreatic TME. Importantly, we developed a novel framework that is based on TF target gene expression to distinguish between environmental- and tumor-specific STAT3 activities in gene expression studies. Using this framework, our results novelly showed that compartment-specific STAT3 activities, but not STAT3 mRNA, have prognostications towards clinical values within pancreatic cancer datasets. In addition, high TME-derived STAT3 activity correlates with an immunosuppressive TME in pancreatic cancer, characterized by CD4 T cell and monocyte infiltration and high copy number variation burden. Where environmental-STAT3 seemed to play a dominant role at primary pancreatic sites, tumor-specific STAT3 seemed dominant at metastatic sites where its high activity persisted. In conclusion, by combining compartment-specific inference with other tumor characteristics, including copy number variation and immune-related gene expression, we demonstrate our method’s utility as a tool to generate novel hypotheses about TFs in tumor biology.

Obesity-Induced Adipose Tissue Inflammation as a Strong Promotional Factor for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is expected to soon become the second leading cause of cancer related deaths in the United States. This may be due to the rising obesity prevalence, which is a recognized risk factor for PDAC. There is great interest in deciphering the underlying driving mechanisms of the obesity–PDAC link. Visceral adiposity has a strong correlation to certain metabolic diseases and gastrointestinal cancers, including PDAC. In fact, our own data strongly suggest that visceral adipose tissue inflammation is a strong promoter for PDAC growth and progression in a genetically engineered mouse model of PDAC and diet-induced obesity. In this review, we will discuss the relationship between obesity-associated adipose tissue inflammation and PDAC development, with a focus on the key molecular and cellular components in the dysfunctional visceral adipose tissue, which provides a tumor permissive environment.

STAT3beta, a distinct isoform from STAT3

STAT3β is an isoform of STAT3 (signal transducer and activator of transcription 3) that differs from the STAT3α isoform by the replacement of the C-terminal 55 amino acid residues with 7 specific residues. The constitutive activation of STAT3α plays a pivotal role in the activation of oncogenic pathways, such as cell proliferation, maturation and survival, while STAT3β is often referred to as a dominant-negative regulator of cancer. STAT3β reveals a "spongy cushion" effect through its cooperation with STAT3α or forms a ternary complex with other co-activators. Especially in tumour cells, relatively high levels of STAT3β lead to some favourable changes. However, there are still many mechanisms that have not been clearly explained in contrast to STAT3α, such as STAT3β nuclear retention, more stable heterodimers and the prolonged Y705 phosphorylation. In addition to its transcriptional activities, STAT3β may also function in the cytosol with respect to the mitochondria, cytoskeleton rearrangements and metastasis of cancer cells. In this review, we summarize the mechanisms that underlie the unique roles of STAT3β combined with total STAT3 to enlighten and draw the attention of researchers studying STAT3 and discuss some interesting questions that warrant answers.

Fatty pancreas: A possible risk factor for pancreatic cancer in animals and humans

Obesity, type 2 diabetes mellitus (T2DM) and aging are associated with pancreatic cancer risk, but the mechanisms of pancreatic cancer development caused by these factors are not clearly understood. Syrian golden hamsters are susceptible to N‐nitrosobis(2‐oxopropyl)amine (BOP)‐induced pancreatic carcinogenesis. Aging, BOP treatment and/or a high‐fat diet cause severe and scattered fatty infiltration (FI) of the pancreas with abnormal adipokine production and promote pancreatic ductal adenocarcinoma (PDAC) development. The KK‐A^y mouse, a T2DM model, also develops severe and scattered FI of the pancreas. Treatment with BOP induced significantly higher cell proliferation in the pancreatic ducts of KK‐A^y mice, but not in those of ICR and C57BL/6J mice, both of which are characterized by an absence of scattered FI. Thus, we hypothesized that severely scattered FI may be involved in the susceptibility to PDAC development. Indeed, severe pancreatic FI, or fatty pancreas, is observed in humans and is associated with age, body mass index (BMI) and DM, which are risk factors for pancreatic cancer. We analyzed the degree of FI in the non‐cancerous parts of PDAC and non‐PDAC patients who had undergone pancreatoduodenectomy by histopathology and demonstrated that the degree of pancreatic FI in PDAC cases is significantly higher than that in non‐PDAC controls. Moreover, the association with PDAC is positive, even after adjusting for BMI and the prevalence of DM. Accumulating evidence suggests that pancreatic FI is involved in PDAC development in animals and humans, and further investigations to clarify the genetic and environmental factors that cause pancreatic FI are warranted.

Angiogenesis in pancreatic cancer: current research status and clinical implications

Pancreatic cancer is one of the most lethal malignancies worldwide. Although the standard of care in pancreatic cancer has improved, prognoses for patients remain poor with a 5-year survival rate of < 5%. Angiogenesis, namely, the formation of new blood vessels from pre-existing vessels, is an important event in tumor growth and hematogenous metastasis. It is a dynamic and complex process involving multiple mechanisms and is regulated by various molecules. Inhibition of angiogenesis has been an established therapeutic strategy for many solid tumors. However, clinical outcomes are far from satisfying for pancreatic cancer patients receiving anti-angiogenic therapies. In this review, we summarize the current status of angiogenesis in pancreatic cancer research and explore the reasons for the poor efficacy of anti-angiogenic therapies, aiming to identify some potential therapeutic targets that may enhance the effectiveness of anti-angiogenic treatments.

Prognostic role of STAT3 in solid tumors: a systematic review and meta-analysis

Accumulated studies have provided controversial evidences of the association between signal transducer and activator of transcription proteins 3 (STAT3) expression and survival of human solid tumors. To address this inconsistency, we performed a meta-analysis with 63 studies identified from PubMed, Medline and EBSCO. We found STAT3 overexpression was significantly associated with worse 3-year overall survival (OS) (OR = 2.06, 95% CI = 1.57 to 2.71, P < 0.00001) and 5-year OS (OR = 2.00, 95% CI = 1.53 to 2.63, P < 0.00001) of human solid tumors. Similar results were observed when disease free survival (DFS) were analyzed. Subgroup analysis showed that elevated STAT3 expression was associated with poor prognosis of gastric cancer, lung cancer, gliomas, hepatic cancer, osteosarcoma, prostate cancer, pancreatic cancer but better prognosis of breast cancer. The correlation between STAT3 and survival of solid tumors was related to its phosphorylated state. High expression level of STAT3 was also associated with advanced tumor stage. In conclusion, elevated STAT3 expression is associated with poor survival in most solid tumors. STAT3 is a valuable biomarker for prognosis prediction and a promising therapeutic target in human solid tumors.

Regulation of EMT by STAT3 in gastrointestinal cancer (Review)

Gastrointestinal (GI) cancer is characterized by its aggressiveness and tendency to metastasize at early stage. Epithelial-mesenchymal transition (EMT), commonly known as the preparing step of metastasis, may account for the aggressive phenotype of GI cancer cells. The process of EMT is finely orchestrated by multiple layers of regulators. Signal transducer and activator of transcription 3 (STAT3) is a transcription factor constitutively activated in diverse malignancies. Recent studies have suggested an involvement of STAT3 in GI cancer EMT. In this review, we first take an insight into the oncogenic functions of STAT3 in GI cancer, and then summarize the possible mechanisms by which STAT3 regulates the EMT process. Through the extensive interactions with EMT-inducing transcription factors and non-coding RNAs, and crosstalk with other signaling pathways, STAT3 has been demonstrated to promote the mesenchymal and invasive phenotype of GI cancer, which provides rationales for specifically targeting STAT3 to prevent and reverse the progression of GI cancer.

Benzyl Isothiocyanate (BITC) Induces Reactive Oxygen Species-dependent Repression of STAT3 Protein by Down-regulation of Specificity Proteins in Pancreatic Cancer

The antineoplastic agent benzyl isothiocyanate (BITC) acts by targeting multiple pro-oncogenic pathways/genes, including signal transducer and activator of transcription 3 (STAT3); however, the mechanism of action is not well known. As reported previously, BITC induced reactive oxygen species (ROS) in Panc1, MiaPaCa2, and L3.6pL pancreatic cancer cells. This was accompanied by induction of apoptosis and inhibition of cell growth and migration, and these responses were attenuated in cells cotreated with BITC plus glutathione (GSH). BITC also decreased expression of specificity proteins (Sp) Sp1, Sp3, and Sp4 transcription factors (TFs) and several pro-oncogenic Sp-regulated genes, including STAT3 and phospho-STAT3 (pSTAT3), and GSH attenuated these responses. Knockdown of Sp TFs by RNA interference also decreased STAT3/pSTAT3 expression. BITC-induced ROS activated a cascade of events that included down-regulation of c-Myc, and it was also demonstrated that c-Myc knockdown decreased expression of Sp TFs and STAT3 These results demonstrate that in pancreatic cancer cells, STAT3 is an Sp-regulated gene that can be targeted by BITC and other ROS inducers, thereby identifying a novel therapeutic approach for targeting STAT3.

Expression of p-STAT3 and vascular endothelial growth factor in MNNG-induced precancerous lesions and gastric tumors in rats

AIM: To investigate the dynamic expression of p-signal transducer and activator of transcription 3 (STAT3) and vascular endothelial growth factor (VEGF) in the formation of gastric tumors induced by drinking water containing N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) in Wistar rats.

METHODS: One hundred and twenty Wistar rats were randomly divided into two groups (60 in each group): Control group and Model group. The rats in each group were then randomly divided into three groups (20 in each group): C/M15, C/M25 and C/M40 (15, 25 and 40 represent the number of feeding weeks from termination). Rats in the control group received normal drinking water and rats in the model group received drinking water containing 100 μg/mL MNNG. Stomach tissues were collected at the end of the 15^th, 25^th and 40^th week, respectively, for microscopic measurement using hematoxylin and eosin staining. The expression of p-STAT3 and VEGF in different pathological types of gastric tissue, including normal, inflammation, atrophy, hyperplasia and gastric stromal tumor, was observed by immunohistochemistry and Western blot, and the corelation between p-STAT3 and VEGF was analyzed.

RESULTS: (1) The expression of p-STAT3 in tissue with gastritis, atrophy, dysplasia and gastric stromal tumor were significantly increased in the model group compared with the control group (2.5 ± 1.0, 2.75 ± 0.36, 6.2 ± 0.45, 5.67 ± 0.55 vs 0.75 ± 0.36, P = 0.026, 0.035, 0.001, 0.002, respectively); the expression of p-STAT3 in tissue with dysplasia was higher than that in samples with gastritis or atrophy (6.2 ± 0.45 vs 2.5 ± 1.0, P = 0.006; 6.2 ± 0.45 vs 2.75 ± 0.36, P = 0.005, respectively); however, the expression of p-STAT3 in gastritis and atrophy was not significantly different (P > 0.05); (2) the expression of VEGF in tissue with gastritis, atrophy, dysplasia and gastric stromal tumor was significantly increased in the model group compared with normal gastric mucosa; and the expression of VEGF in tissue with dysplasia was higher than that in tissue with inflammation and atrophy (10.8 ± 1.96 vs 7.62 ± 0.25, P = 0.029; 10.8 ± 1.96 vs 6.26 ± 0.76, P = 0.033, respectively); similarly, the expression of VEGF in tissue with gastritis and atrophy was not significantly different (P > 0.05); and (3) the expression of VEGF was positively correlated with p-STAT3.

CONCLUSION: p-STAT3 plays an important role in gastric cancer formation by regulating the expression of VEGF to promote the progression of gastric tumor from gastritis.

Phage display screening identifies a novel peptide to suppress ovarian cancer cells in vitro and in vivo in mouse models

Background

Ovarian cancer is a possibly lethal gynecological malignancy and this study utilized phage display technology to screen and identify peptides that specifically bind to ovarian cancer cells and explored the effects of these peptides on ovarian cancer cells in vitro and in vivo.

Methods

The phage displayed peptide library was used to isolate the peptides binding to and internalizing into the ovarian carcinoma cells. Positive phage clones were characterized with DNA sequencing and bioinformatics analysis and then validated with immunofluorescence. Subsequently, the selected peptides were investigated for their cancer-related functions, including cell adhesion, spreading, motility, and invasion in vitro and in vivo.

Results

Peptide1 read as SWQIGGNwas the positive peptide and showed preferential binding to the target cells. Peptide 1 also inhibited cell proliferation, migration, invasion and adhesion of ovarian cancer HO8910 cells in vitro. In vivo, Peptide 1 led to a lower tumorigenicity of HO8910 cells, which was characterized by the inhibitory effect on tumor growth and metastasis of ovarian cells.

Conclusion

These studies demonstrate that the phage display-identified tumor cell-binding peptide was able to control ovarian cancer cell viability, migration, invasion, and adhesion capacity in vitro as well as tumor growth and metastasis in vivo. Future studies will be aimed at evaluating the clinical efficacy of the peptide SWQIGGN in ovarian cancer patients.

Prognostic Role of Phospho-STAT3 in Patients with Cancers of the Digestive System: A Systematic Review and Meta-Analysis

OBJECTIVE

The definite prognostic role of p-STAT3 has not been well defined. We performed a meta-analysis evaluating the prognostic role of p-STAT3 expression in patients with digestive system cancers.

METHODS

We searched the available articles reporting the prognostic value of p-STAT3 in patients with cancers of the digestive system, mainly including colorectal cancer, gastric cancer, hepatocellular carcinoma, esophagus cancer and pancreatic cancer. The pooled hazard ratios (HRs) with 95 % confidence intervals (95 % CIs) of overall survival (OS) and disease-free survival (DFS) were used to assess the prognostic role of p-STAT3 expression level in cancer tissues. And the association between p-STAT3 expression and clinicopathological characteristics was evaluated.

RESULTS

A total of 22 studies with 3585 patients were finally enrolled in the meta-analysis. The results showed that elevated p-STAT3 expression level predicted inferior OS (HR = 1.809, 95% CI: 1.442-2.270, P < 0.001) and DFS (HR = 1.481, 95% CI: 1.028-2.133, P = 0.035) in patients with malignant cancers of the digestive system. Increased expression of p-STAT3 is significantly related with tumor cell differentiation (Odds ratio (OR) = 1.895, 95% CI: 1.364-2.632, P < 0.001) and lymph node metastases (OR = 2.108, 95% CI: 1.104-4.024, P = 0.024). Sensitivity analysis suggested that the pooled HR was stable and omitting a single study did not change the significance of the pooled HR. Funnel plots and Egger's tests revealed there was no significant publication bias in the meta-analysis.

CONCLUSION

Phospho-STAT3 might be a prognostic factor of patients with digestive system cancers. More well designed studies with adequate follow-up are needed to gain a thorough understanding of the prognostic role of p-STAT3.

What are the macrophages and stellate cells doing in pancreatic adenocarcinoma?

Pancreatic ductal adenocarcinoma is a devastating disease characterized by a dense desmoplastic stroma. Chemo- and radio-therapeutic strategies based on targeting cancer cells have failed in improving the outcome of this cancer suggesting important roles for stroma in therapy resistance. Cells in the tumor stroma have been shown to regulate proliferation, resistance to apoptosis and treatments, epithelial to mesenchymal transition (EMT) and stemness of cancer cells. Stellate cells in their activated state have been thought over the past decade to only have tumor promoting roles. However, recent findings suggest that stellate cells may have protective roles as well. The present review highlights the latest findings on the role of two major components of tumor stroma, pancreatic stellate cells and macrophages, in promoting or inhibiting pancreatic cancer, focused on their effects on EMT and cancer stemness.

Expression of signal transducer and activator of transcription 3 and its phosphorylated form is significantly upregulated in patients with papillary thyroid cancer

The aim of the present study was to investigate the expression of signal transducer and activator of transcription 3 (STAT3) and phosphorylated STAT3 (pSTAT3) in tissues of papillary thyroid cancer (PTC) in comparison with the expression in adjacent normal tissues. The expression of STAT3, pSTAT3, fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor-C (VEGF-C) was examined in tissues of 42 cases of PTC and the adjacent normal tissues of 20 of the 42 PTC cases using immunohistochemistry and western blotting. The association between the expression levels and the clinicopathological features was analyzed. The expression of STAT3, pSTAT3, FGF2 and VEGF-C in the PTC tissues (76.2, 42.9, 81.0 and 73.8%, respectively) was significantly higher than that in the normal tissues (P<0.05). In the PTC tissues, the expression of STAT3 was linearly correlated with the levels of pSTAT3 and VEGF-C (P<0.05). In conclusion, STAT3 and pSTAT3 are significantly upregulated in PTC tissues, and may potentially be used as markers to screen for PTC with lymph node metastasis.

Magnetic nanosphere-guided site-specific delivery of vascular endothelial growth factor gene attenuates restenosis in rabbit balloon-injured artery

OBJECTIVE

New and efficient strategies to protect endothelium or to enhance endothelial regrowth are important for treatment of restenosis after percutaneous transluminal angioplasty. Magnetic DNA microspheres are used to accelerate vascular endothelial growth factor (VEGF) re-endothelialization and to attenuate intimal hyperplasia in balloon-injured artery. This study aimed to assess DNA-gelatin magnetic nanospheres containing VEGF expression plasmids in vascular restenosis attenuation.

METHODS

Ninety-six rabbits underwent balloon injury and were randomly divided for gene transfer with naked VEGF plasmids (NAK group), magnetic VEGF microspheres (MIC group), and LacZ (CON group: naked LacZ plasmid and LacZ nanosphere subgroups). Serum and tissue VEGF levels were measured. Also, the ratios of intima area to media area were determined to assess neointima formation.

RESULTS

Microsphere gene delivery through the artery by a magnet resulted in VEGF overexpression in transfected arterial segments. Tissue VEGF integral optical densities were significantly increased in MIC rabbits compared with NAK animals. Serum VEGF was below detection in all animals. X-Gal staining showed higher transfection efficiency in the CON group. The impact of neointimal thickening was evaluated by light microscopy as the ratio of intima area to media area in cross sections. Significant differences in the ratio of intima area to media area were obtained between the NAK group (0.12 ± 0.02, 0.41 ± 0.03, 0.61 ± 0.05, and 0.72 ± 0.04 at 1, 2, 3, and 4 weeks, respectively) and the MIC group (0.06 ± 0.03, 0.20 ± 0.05, 0.25 ± 0.04, and 0.26 ± 0.03 at 1, 2, 3, and 4 weeks, respectively) at 2, 3, and 4 weeks (P < .05).

CONCLUSIONS

Intra-arterial VEGF gene delivery by magnetic microspheres significantly increased DNA stability, transfection efficiency, and targeting specificity, resulting in exogenous VEGF overexpression and attenuated intimal hyperplasia in balloon-injured artery.

Patients with pancreatic adenocarcinoma exhibit elevated levels of myeloid-derived suppressor cells upon progression of disease

Elevated levels of myeloid-derived suppressor cells (MDSCs) induced by tumor-derived factors are associated with inhibition of immune responses in patients with gastrointestinal malignancies. We hypothesized that pro-MDSC cytokines and levels of MDSC in the peripheral blood would be elevated in pancreatic adenocarcinoma patients with progressive disease. Peripheral blood mononuclear cells (PBMCs) were isolated from 16 pancreatic cancer patients undergoing chemotherapy and phenotyped for MDSC using a five antigen panel (CD33, HLA-DR, CD11b, CD14, CD15). Patients with stable disease had significantly lower MDSC levels in the peripheral blood than those with progressive disease (1.41 ± 1.12 vs. 5.14 ± 4.58 %, p = 0.013, Wilcoxon test). A cutoff of 2.5 % MDSC identified patients with progressive disease. Patients with ECOG performance status ≥2 had a weaker association with increased levels of MDSC. Plasma was obtained from 15 chemonaive patients, 13 patients undergoing chemotherapy and 9 normal donors. Increases in the levels of pro-MDSC cytokines were observed for pancreatic cancer patients versus controls, and the pro-MDSC cytokine IL-6 was increased in those patients undergoing chemotherapy. This study suggests that MDSC in peripheral blood may be a predictive biomarker of chemotherapy failure in pancreatic cancer patients.

Uncovering influence links in molecular knowledge networks to streamline personalized medicine

OBJECTIVES

We developed Resource Description Framework (RDF)-induced InfluGrams (RIIG) - an informatics formalism to uncover complex relationships among biomarker proteins and biological pathways using the biomedical knowledge bases. We demonstrate an application of RIIG in morphoproteomics, a theranostic technique aimed at comprehensive analysis of protein circuitries to design effective therapeutic strategies in personalized medicine setting.

METHODS

RIIG uses an RDF "mashup" knowledge base that integrates publicly available pathway and protein data with ontologies. To mine for RDF-induced Influence Links, RIIG introduces notions of RDF relevancy and RDF collider, which mimic conditional independence and "explaining away" mechanism in probabilistic systems. Using these notions and constraint-based structure learning algorithms, the formalism generates the morphoproteomic diagrams, which we call InfluGrams, for further analysis by experts.

RESULTS

RIIG was able to recover up to 90% of predefined influence links in a simulated environment using synthetic data and outperformed a naïve Monte Carlo sampling of random links. In clinical cases of Acute Lymphoblastic Leukemia (ALL) and Mesenchymal Chondrosarcoma, a significant level of concordance between the RIIG-generated and expert-built morphoproteomic diagrams was observed. In a clinical case of Squamous Cell Carcinoma, RIIG allowed selection of alternative therapeutic targets, the validity of which was supported by a systematic literature review. We have also illustrated an ability of RIIG to discover novel influence links in the general case of the ALL.

CONCLUSIONS

Applications of the RIIG formalism demonstrated its potential to uncover patient-specific complex relationships among biological entities to find effective drug targets in a personalized medicine setting. We conclude that RIIG provides an effective means not only to streamline morphoproteomic studies, but also to bridge curated biomedical knowledge and causal reasoning with the clinical data in general.

IL-6 and related cytokines as the critical lynchpins between inflammation and cancer

Inflammatory responses play pivotal roles in cancer development, including tumor initiation, promotion, progression, and metastasis. Cytokines are now recognized as important mediators linking inflammation and cancer, and are therefore potential therapeutic and preventive targets as well as prognostic factors. The interleukin (IL)-6 family of cytokines, especially IL-6 and IL-11, is highly up-regulated in many cancers and considered as one of the most important cytokine families during tumorigenesis and metastasis. This review discusses molecular mechanisms linking the IL-6 cytokine family to solid malignancies and their treatment.

Effects of AG490 and S3I-201 on regulation of the JAK/STAT3 signaling pathway in relation to angiogenesis in TRAIL-resistant prostate cancer cells in vitro

The aim of the present study was to analyze the molecular mechanisms involved in blocking the signaling pathway and the effects of this on the progression of prostate cancer (CaP) cells in vitro. LNCaP human CaP cell line was stimulated with interleukin-6 (IL-6) in the presence/absence of Janus kinase (JAK) 2 (AG490), signal transducer and activator of transcription 3 [(STAT3) S3I-201] inhibitors and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Cytotoxic activity, the activation of phosphorylated (p)-STAT3 protein, caspase (CASP) 3 activity at protein level, vascular endothelial growth factor (VEGF) A, VEGFC, vascular endothelial growth factor receptor 2, STAT3, matrix metalloproteinase-2, myeloid cell leukemia sequence 1 (MCL-1), CASP8 and CASP9 messenger RNA (mRNA) levels were determined. Morphology and apoptosis were confirmed by DAPI staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. IL-6 rapidly induced the phosphorylation of STAT3 in a dose- and time-dependent manner with a peak expression at 3 h at a concentration of 25 ng/ml. In addition, AG490 (50 μM) and S3I-201 (300 μM) inhibited STAT3 activation. Western blotting results revealed that p-STAT3 protein expression decreased significantly with AG490 and S3I-201 treatment in LNCaP cells. AG490 and S3I-201 induced the downregulation of VEGFA, MCL-1 and STAT3 and the upregulation of CASP8 and CASP9 mRNA transcription levels. In addition, the inhibitors increased the level of CASP3 protein. Combinations of AG490- and S3I-201-TRAIL did not result in an increase in this effect. Parallel results were found by DAPI staining and TUNEL assay. To the best of our knowledge, this is the first study to investigate the possible clinical use of AG490 or S3I-201, together with the reduced use of chemotherapeutic agents with high cytotoxicity, for their ability to exert an apoptotic effect, targeting the JAK/STAT3 pathway.

FOXM1 and its oncogenic signaling in pancreatic cancer pathogenesis

Pancreatic cancer is a devastating disease with an overall 5-year survival rate less than 5%. Multiple signaling pathways are implicated in the pathogenesis of pancreatic cancer, such as Wnt/β-catenin, Notch, Hedgehog, hypoxia-inducible factor, signal transducer and activator of transcription, specificity proteins/Krüppel-like factors, and Forkhead box (FOX). Recently, increasing evidence has demonstrated that the transcription factor FOXM1 plays important roles in the initiation, progression, and metastasis of a variety of human tumors, including pancreatic cancer. In this review, we focus on the current understanding of the molecular pathogenesis of pancreatic cancer with a special focus on the function and regulation of FOXM1 and rationale for FOXM1 as a novel molecular target for pancreatic cancer prevention and treatment.

MUC4-induced nuclear translocation of β-catenin: a novel mechanism for growth, metastasis and angiogenesis in pancreatic cancer

The membrane mucin MUC4 is aberrantly expressed in multiple cancers and is of clinical significance to diagnosis and prognosis in pancreatic cancer. However, the role of MUC4 in angiogenesis and the potential association among these malignant capabilities have not been explored. In this study, we investigated the collective signaling mechanisms associated with MUC4-induced growth, metastasis and angiogenesis in pancreatic cancer. Knockdown of MUC4 in two pancreatic cancer cell lines led to downregulation of lysosomal degradation of E-cadherin by Src kinase through downregulation of pFAK and pSrc pathway. The downregulation of lysosomal degradation of E-cadherin in turn induced the formation of E-cadherin/β-catenin complex and membrane translocation of β-catenin, resulting in the downregulation of Wnt/β-catenin signaling pathway. Thus, the Wnt/β-catenin target genes c-Myc, Cyclin D1, CD44 and VEGF were down-regulated and their malignant functions proliferation, metastasis and angiogenesis were reduced. Taken together, MUC4-induced nuclear translocation of β-catenin is a novel mechanism for growth, metastasis and angiogenesis of pancreatic cancer.

Phosphorylation of STAT3 correlates with HER2 status, but not with survival in pancreatic ductal adenocarcinoma

Activation of signal-transcriptional factor signal transducer and activator of transcription 3 (STAT3) is associated with more aggressive behaviour in a variety of human malignancies. As selective STAT3 inhibitors exist, this protein might represent a novel therapeutic target. Although STAT3 seems to play an important role in progression of pancreatic ductal carcinoma (PDAC), only few data on this subject exist. The aim of our study was the investigation of STAT3 activation and its correlation with its possible regulator HER2. Expression of tyrosine-705 phosphorylated STAT3 (pSTAT3) was determined immunohistochemically in 79 PDACs. HER2 status assessed by immunohistochemistry and double colour silver in situ hybridization was available from a previous study. PSTAT3 expression was seen in 33 (41.8%) patients. Six patients were scored as HER2 positive having strong correlation with pSTAT3 expression (p = 0.004, Fisher's exact test). No association of pSTAT3 expression with patients' age, tumour staging and grading, perineural invasion of tumour cells or survival time was seen. pSTAT3 is frequently expressed in PDAC. Nevertheless, its immediate clinical relevance seems to be low. However, further research needs to determine whether STAT3 status in PDAC is predictive for the response to novel targeting therapies.

Protein kinase B phosphorylation correlates with vascular endothelial growth factor A and microvessel density in gastric adenocarcinoma

OBJECTIVE

The signalling molecule protein kinase B (Akt) modulates many cellular processes. Phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathways play important roles in tumour angiogenesis. The aim of this study was to determine the role of phosphorylated Akt (pAkt) in angiogenesis and its correlation with vascular endothelial growth factor (VEGF)-A in gastric adenocarcinoma.

METHODS

Tumour tissue and matched healthy gastric mucosa were obtained from patients undergoing surgical resection of gastric adenocarcinoma. Akt and pAkt were detected via Western blotting. VEGF-A, pAkt and CD34 were examined by immunohistochemistry.

RESULTS

Akt and pAkt protein levels were significantly higher in gastric cancer tissue than in normal tissue (n = 48 patients). Positive VEGF-A immunostaining was significantly associated with pAkt immunostaining. Microvessel density was correlated with both VEGF-A and pAkt positivity.

CONCLUSIONS

Phosphorylated Akt and VEGF-A are involved in angiogenesis of gastric adenocarcinoma, and Akt activation may contribute to angiogenesis via VEGF-A upregulation. The PI3K/Akt/VEGF signalling pathway may be involved in gastric adeno carcinoma.

Relationship between STAT3 activation and epithelial-mesenchymal transition in gastric carcinoma

AIM: To detect the expression of signal transducer and activator of transcription 3 (STAT3) and phosphorylated STAT3 (p-STAT3) in gastric carcinoma (GC) and to analyze their relationship with epithelial-mesenchymal transition (EMT), tumor invasion and metastasis.

METHODS: The expression of STAT3, p-STAT3, E-cadherin and Vimentin proteins in 53 GC specimens and matched normal gastric mucosal specimens was detected by immunohistochemistry. The correlation of expression of STAT3, p-STAT3, E-cadherin and Vimentin proteins with clinicopathological parameters of GC was analyzed.

RESULTS: The positive rates of STAT3, p-STAT3 and Vimentin expression were significantly higher and that of E-cadherin was significantly lower in GC than that in normal gastric mucosal tissues (all P < 0.01). The expression of STAT3, p-STAT3, E-cadherin and Vimentin proteins was significantly correlated with tumor differentiation, depth of invasion, lymph node metastasis and clinical stage (all P < 0.05), but not with gender, age, tumor size (all P > 0.05). STAT3 and p-STAT3 expression was negatively correlated with E-cadherin expression (r = -0.360, -0.335; P = 0.008, 0.014), but positively with Vimentin expression (r = 0.443, 0.346; P = 0.001, 0.011) in GC.

CONCLUSION: STAT3 and p-STAT3 protein expression is up-regulated in GC, and up-regulation of STAT3 and p-STAT3 protein expression in GC is significantly correlated with E-cadherin and Vimentin expression. These findings suggest that EMT may be mediated by the activation of the STAT3 signaling pathway.

Aberrant, ectopic expression of VEGF and VEGF receptors 1 and 2 in malignant colonic epithelial cells. Implications for these cells growth via an autocrine mechanism

Vascular endothelial growth factor A (referred to as VEGF) is implicated in colon cancer growth. Currently, the main accepted mechanism by which VEGF promotes colon cancer growth is via the stimulation of angiogenesis, which was originally postulated by late Judah Folkman. However, the cellular source of VEGF in colon cancer tissue; and, the expression of VEGF and its receptors VEGF-R1 and VEGF-R2 in colon cancer cells are not fully known and are subjects of controversy.

MATERIAL AND METHODS

We examined and quantified expression of VEGF, VEGF-R1 and VEGF-R2 in three different human colonic tissue arrays containing sections of adenocarcinoma (n=43) and normal mucosa (n = 41). In human colon cancer cell lines HCT116 and HT29 and normal colon cell lines NCM356 and NCM460, we examined expression of VEGF, VEGF-R1 and VEGF-R2 mRNA and protein, VEGF production and secretion into the culture medium; and, the effect of a potent, selective inhibitor of VEGF receptors, AL-993, on cell proliferation.

RESULTS

Human colorectal cancer specimens had strong expression of VEGF in cancer cells and also expressed VEGF-R1 and VEGF-R2.In vitro studies showed that human colon cancer cell lines, HCT116 and HT29, but not normal colonic cell lines, express VEGF, VEGF-R1 and VEGF-R2 and secrete VEGF into the medium up to a concentration 2000 pg/ml within 48 h. Furthermore, we showed that inhibition of VEGF receptors using a specific VEGF-R inhibitor significantly reduced proliferation (by >50%) of cultured colon cancer cell lines.

CONCLUSIONS

Our findings support the contention that VEGF generated by colon cancer cells stimulates their growth directly through an autocrine mechanism that is independent of its primary function in the induction of angiogenesis.

Pancreatic cancer-associated stellate cells promote differentiation of myeloid-derived suppressor cells in a STAT3-dependent manner

Pancreatic stellate cells (PSC) are a subset of pancreatic cancer-associated fibroblasts. These cells provide prosurvival signals to tumors; however, little is known regarding their interactions with immune cells within the tumor microenvironment. We hypothesized that factors produced by human PSC could enhance myeloid-derived suppressor cell (MDSC) differentiation and function, which promotes an immunosuppressive microenvironment. Primary PSC cell lines (n = 7) were generated from human specimens and phenotypically confirmed via expression of vimentin, α-smooth muscle actin (α-SMA), and glial fibrillary acidic protein (GFAP). Luminex analysis indicated that PSC but not human fetal primary pancreatic fibroblast cells (HPF; negative controls) produced MDSC-promoting cytokines [interleukin (IL-6), VEGF, macrophage colony-stimulating factor (M-CSF) ] and chemokines (SDF-1, MCP-1). Culture of peripheral blood mononuclear cells [peripheral blood mononuclear cell (PBMC), n = 3 donors] with PSC supernatants or IL-6/granulocyte macrophage colony-stimulating factor (GM-CSF; positive control) for 7 days promoted PBMC differentiation into an MDSC (CD11b+CD33+) phenotype and a subpopulation of polymorphonuclear CD11b+CD33+CD15+ cells. The resulting CD11b+CD33+ cells functionally suppressed autologous T-lymphocyte proliferation. In contrast, supernatants from HPF did not induce an MDSC phenotype in PBMCs. Culture of normal PBMCs with PSC supernatants led to STAT3 but not STAT1 or STAT5 phosphorylation. IL-6 was an important mediator as its neutralization inhibited PSC supernatant-mediated STAT3 phosphorylation and MDSC differentiation. Finally, the FLLL32 STAT3 inhibitor abrogated PSC supernatant-mediated MDSC differentiation, PSC viability, and reduced autocrine IL-6 production indicating these processes are STAT3 dependent. These results identify a novel role for PSC in driving immune escape in pancreatic cancer and extend the evidence that STAT3 acts as a driver of stromal immunosuppression to enhance its interest as a therapeutic target.

Genetically engineered mouse models of pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of human cancer for which there are no effective therapies. Deep sequencing of PDAC tumors has revealed the presence of a high number of mutations (>50) that affect at least a dozen key signaling pathways. This scenario highlights the urgent need to develop experimental models that faithfully reproduce the natural history of these human tumors in order to understand their biology and to design therapeutic approaches that might effectively interfere with their multiple mutated pathways. Over the last decade, several models, primarily based on the genetic activation of resident KRas oncogenes knocked-in within the endogenous KRas locus have been generated. These models faithfully reproduce the histological lesions that characterize human pancreatic tumors. Decoration of these models with additional mutations, primarily involving tumor suppressor loci known to be also mutated in human PDAC tumors, results in accelerated tumor progression and in the induction of invasive and metastatic malignancies. Mouse PDACs also display a desmoplastic stroma and inflammatory responses that closely resemble those observed in human patients. Interestingly, adult mice appear to be resistant to PDAC development unless the animals undergo pancreatic damage, mainly in the form of acute, chronic or even temporary pancreatitis. In this review, we describe the most representative models available to date and how their detailed characterization is allowing us to understand their cellular origin as well as the events involved in tumor progression. Moreover, their molecular dissection is starting to unveil novel therapeutic strategies that could be translated to the clinic in the very near future.

Vascular endothelial growth factor receptor-3 expression in mycosis fungoides

Here, we have studied vascular endothelial growth factor receptor-3 (VEGFR-3) expression in mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma (CTCL). Immunohistochemistry revealed that in two-thirds of 34 patients, VEGFR-3 was expressed in situ by both tumor and stromal cells irrespective of the disease stage. The natural VEGFR-3 ligand, VEGF-C, partially protected malignant T-cell lines from growth inhibition by the histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA). Whereas the malignant T cells did not produce VEGF-C in vitro, its expression was induced during tumor formation in vivo in a xenograft mouse model of MF. In conclusion, malignant and stromal cells express high levels of VEGFR-3 in all stages of MF. Moreover, malignant T cells trigger enhanced VEGF-C expression in fibroblasts, suggesting that cross-talk between tumor and stromal cells plays a role in lymphangiogenesis and possibly disease progression.

The expression and clinical significance of PI3K, pAkt and VEGF in colon cancer

Background PI3K/Akt signaling has been shown to be activated in a variety of cancers. However, the correlation between Akt activation and VEGF expression is unclear in colon cancer tissues. This study aimed to investigate the expression and predictive value of phosphorylated Akt (pAkt) and VEGF in colon cancer tissues. The expression of PI3K, pAkt and VEGF was detected by immunohistochemical staining in 60 samples of colon cancer tissues and their corresponding adjacent normal colon tissues. In addition, the correlations between the expression levels of the 3 proteins and the clinicopathological parameters of the colon cancer cases were analyzed. The positive rates of PI3K, pAkt and VEGF expression were 71.7% (43/60), 68.3% (41/60) and 61.7% (37/60) in colon cancer, respectively, which were significantly higher than in adjacent normal colon tissues (P<0.001). Correlation analyses showed that PI3K expression was not significantly associated with the gender or age of the patients, tumor size or differentiation (P>0.05), but was closely associated with serous coat infiltration and lymphatic metastasis of colon cancer (P<0.05). Neither pAkt nor VEGF expression were significantly associated with the gender or age of the patients, or tumor differentiation (P>0.05), but were closely associated with tumor size, serous coat infiltration and lymphatic metastasis of colon cancer (P<0.05). In addition, the expression levels of Pl3K and pAkt were positively correlated with that of VEGF in colon cancer tissues (P<0.05). Our data show a positive correlation between PI3K/Akt activation and VEGF expression in colon cancer tissues and indicate that pAkt is an independent prognostic marker for colon cancer patients.