Xanthine oxidoreductase – Clinical significance in colorectal cancer and in vitro expression of the protein in human colon cancer cells

Xanthine oxidoreductase (XOR) is a key enzyme in degradation of DNA and RNA, and has previously been shown to be decreased in aggressive breast and gastric cancer. In this study, XOR expression was assessed in tissue microarray specimens of 478 patients with colorectal cancer and related to clinical parameters. In addition, we performed in vitro studies of XOR activity, protein and mRNA in colon cancer cells (Caco-2). Results from the tissue expression analyses show that XOR was decreased in 62% and undetectable in 22% of the tumours as compared to normal tissue. Loss of XOR was associated with poor grade of differentiation (p = 0.006) and advanced Dukes stage (p = 0.03). In multivariate survival analysis, XOR was a prognostic factor (p = 0.008), independent of Dukes stage, histological grade, age and tumour location. The in vitro analyses show that XOR is not measurable in undifferentiated Caco-2 cells, but appears and increases with differentiation. We conclude that XOR expression is associated with histological grade of differentiation and extent of disease in colorectal cancer, and it provides significant prognostic information independently of established factors.     

Oncogenic KRAS modulates mitochondrial metabolism in human colon cancer cells by inducing HIF-1α and HIF-2α target genes

Background  

Activating KRAS mutations are important for cancer initiation and progression; and have recently been shown to cause primary resistance to therapies targeting the epidermal growth factor receptor. Therefore, strategies are currently in development to overcome treatment resistance due to oncogenic KRAS. The hypoxia-inducible factors-1α and -2α (HIF-1α and HIF-2α) are activated in cancer due to dysregulated ras signaling.     

Clinicopathological significance of chemotactic factor IL-8, MCP-1 and MIP-1α expressions in gallbladder carcinoma

Objective:Gal bladder carcinoma was one of the malignant tumors in the digestive system, characterized by high recurrence and invasion. Recent research indicates that chemotactic factors such as IL-8, ...     

Clinicopathological and prognostic significance of hypoxia-inducible factor-1α in esophageal squamous cell carcinoma: a meta-analysis

Published literatures on the prognostic value of hypoxia-inducible factor-1α (HIF-1α) overexpression in esophageal squamous cell carcinoma (ESCC) are conflicting and heterogeneous. We performed a meta-analysis to more precisely evaluate the clinicopathological and prognostic value of HIF-1α in patients with ESCC. Searches were applied to MEDLINE, Pubmed, Embase, Cochrane Library, Web of Science, and Chinese BioMedical Literature Databases until September 10, 2013, without language restrictions. The pooled hazard ratios (HRs) and odds ratios (ORs) with corresponding 95 % confidence intervals (CIs) were used to estimate the effects. Twelve studies with 942 ESCC patients were selected to evaluate the correlation between HIF-1α and overall survival (OS), disease-free survival (DFS), response to chemoradiation (RC), and clinicopathological features. HIF-1α overexpression was significantly associated with poor OS (HR 1.78, 95 % CI 1.41–2.24), DFS (HR 1.91, 95 % CI 1.15–3.18), and RC (HR 3.56, 95 % CI 1.68–7.53). Besides, HIF-1α overexpression was significantly associated with stage (OR 2.90, 95 % CI 1.97–4.27), lymph node metastasis (OR 1.86, 95 % CI 1.39–2.49), depth of invasion (OR 2.45, 95 % CI 1.24–4.86), lymphatic invasion (OR 2.28, 95 % CI 1.46–3.56), distant metastasis (OR 2.04, 95 % CI 1.19–3.50), and vascular endothelial growth factor (OR 3.67, 95 % CI 1.81–7.46). Our results indicate that HIF-1α overexpression can potently predict the poor prognosis and chemoradiation resistance for ESCC. Large prospective studies with multivariable survival analyses are now needed to confirm the clinical utility of HIF-1α as an independent prognostic marker.     

High frequency of HIF-1α overexpression in BRCA1 related breast cancer

Hypoxia is a hallmark of cancer. Hypoxia inducible factor-1α (HIF-1α) is the key regulator of the hypoxia response. HIF-1α is overexpressed during sporadic breast carcinogenesis and correlated with poor prognosis. Little is known on the role of HIF-1α in hereditary breast carcinogenesis. A recent study suggests a role for BRCA1 in HIF-1α regulation. We therefore examined the expression of HIF-1α in BRCA1 related breast cancers. By immunohistochemistry we studied expression of HIF-1α and some of its downstream targets in 30 hereditary invasive breast cancers in comparison with 200 sporadic controls. HIF-1α overexpression was significantly more frequent in BRCA1 related breast cancers (27/30, 90%) than in sporadic controls (88/200, 44%) (P < 0.0001). 19/30 (63%) of BRCA1 tumors showed perinecrotic (hypoxia induced) and 8/30 (27%) a diffuse HIF-1α overexpression pattern, the latter more likely related to genetic alterations in oncogenes and tumor suppressor genes. In contrast, sporadic breast cancer HIF-1 expressing tumors showed an inverse ratio of perinecrotic/diffuse expression (31 vs. 69%, P = 0.0002). Glut-1 and CAIX, downstream HIF1 targets, were expressed in 27/30 (90%) and 15/21 (71%) of hereditary cases versus 54/183 (29%) and 24/183 (13%) in sporadic cases. p300 levels, necessary for HIF-1 downstream activation, were significantly higher in hereditary cases (20/21, 95%) compared to sporadic cases (91/183, 50%, P = 0.0001). In conclusion, in BRCA1 germline mutation related breast cancer, functional HIF-1α overexpression is seen at a much higher frequency than in sporadic breast cancer, mostly hypoxia induced. This points to an important role of hypoxia and its key regulator HIF-1α in hereditary breast carcinogenesis.     

The expression and clinical significance of β-catenin and colorectal cancer stem cells marker EpCAMhigh/CD44+ in colorectal cancer

Objective

The aim of the study was to explore the role of Wnt/β-catenin signalling pathway in the maintenance, invasion and metastasis of colorectal cancer stem cells.

Methods

Double immunohistochemical staining was used to detect the expression of EpCAM^high/CD44⁺ which is regarded as the marker of colorectal cancer stem cells in 80 cases of colorectal cancer and their corresponding liver metastases. The SP method of immunohistochemistry was used to detect the expression of the key protein β-catenin in the Wnt pathway in these tissue. The expression and correlation of β-catenin and EpCAM^high/CD44⁺ in colorectal cancer were analyzed and their role on the biological behavior of colorectal cancer was explored.

Results

The abnormal expression of β-catenin was significantly higher in colorectal cancer than in the paraneoplastic normal intestinal mucosa [55% (44/80) vs 10% (2/20), P < 0.05]. The positive expression of EpCAM^high/CD44⁺ was significantly higher in colorectal cancer than in the paraneoplastic normal intestinal mucosa [66.25% (53/80) vs 0% (0/20), P < 0.05]. In the 80 cases of colorectal cancer, the abnormal expression of β-catenin has no correlation with gender (P = 0.079), age (P = 0.416) and the magnitude (P = 0.816) of the tumor (P > 0.05), but it was significantly correlated with degree of differentiation (P = 0.001), depth of invasion (P = 0.001), clinical stage (P = 0.000) and metastasis (P = 0.000). In the colorectal cancer, the expression of EpCAM^high/CD44⁺ cells has no correlation with gender (P = 0.934) and the magnitude (P = 0.160) of the tumor (P > 0.05), but was significantly correlated with age (P = 0.021), degree of differentiation (P = 0.013), depth of invasion (P = 0.000), clinical stage (P = 0.000) and metastasis (P = 0.000). In the corresponding liver metastases, we could also detecte EpCAM^high/CD44⁺ cells. In cases with abnormal expression of β-catenin, the positive expression rate of EpCAM^high/CD44⁺ was significantly higher than those with normal expression of β-catenin (84.1% vs 44.4%), and the difference was statistically significant (P < 0.05).

Conclusion

The abnormal activation of Wnt/β-catenin signalling pathway may prompt the abnormal proliferation of the colorectal cancer stem cells, which leads to the recurrence and metastasis of the cancer.     

Berberine enhances radiosensitivity of esophageal squamous cancer by targeting HIF-1α in vitro and in vivo

Radiation therapy is an important treatment approach for esophageal squamous cell carcinoma (ESCC). However, how to promote radiation sensitivity in ESCC remains a challenge. This study aimed to evaluate the effects of berberine, a common used Chinese medicine, on the radiosensitivity of ESCC. ECSS cell line ECA109 and TE13 were subjected to hypoxia and/or ionizing radiation (IR), in the presence or absence of berberine treatment. Cell growth and survival, and apoptosis were evaluated. In addition, ECA109 cells were xenografted into nude mice and subjected to IR and/or berberine treatment. The expression of HIF-1α and VEGF was detected by western blot and immunohistochemical analysis. Our results showed that berberine increased radiosensitivity of ESCC cells and xenografts, and this was associated with the inhibition of HIF-1α and VEGF expression. These data suggest that berberine may be a potential radiotherapy sensitization drugs due to its significant anti-hypoxia activity.     

Study on the expression and significance of TGF-��1, p-ERK1/2and K-ras in colorectal cancer using tissue microarray technique

Objective  

This study aimed to explore the expression and significance of transforming growth factor β1(TGF-β1), extracellular signal-regulated kinases 1/2 (ERK1/2), and K-ras in colorectal cancer (CRC) using tissue microarray technology.     

Inhibitory effects of epigallocatechin-3-gallate on cell proliferation and the expression of HIF-1α and P-gp in the human pancreatic carcinoma cell line PANC-1

The aim of this study was to verify the inhibitory effects of epigallocatechin-3-gallate (EGCG) on cell proliferation and the expression of hypoxia-inducible factor 1 (HIF-1α) and multidrug resistance protein 1 (MDR1/P-gp) in the human pancreatic carcinoma cell line PANC-1, thereby, reversing drug resistance of pancreatic carcinoma and improving its sensitivity to cancer chemotherapy. The human pancreatic carcinoma cell line PANC-1 was incubated under hypoxic conditions with different concentrations of epigallocatechin-3-gallate (EGCG) for indicated hours. The effects of EGCG on the mRNA or protein expression of HIF-1α and MDR1 were determined by RT-PCR or western blotting. Cellular proliferation and viability assays were measured using Cell Counting Kit-8. Western blotting revealed that EGCG inhibits the expression of the HIF-1α protein in a dose-dependent manner, while RT-PCR showed that it does not have any effects on HIF-1α mRNA. In addition, EGCG attenuated the mRNA and protein levels of P-gp in a dose-dependent manner, reaching a peak at the highest concentration. Furthermore, EGCG inhibited the proliferation of PANC-1 cells in a concentration- and time-dependent manner. The attenuation of HIF-1α and the consequently reduced P-gp could contribute to the inhibitory effects of EGCG on the proliferation of PANC-1 cells.