BackgroundTumor hypoxia is an important factor related to tumor resistance to radiotherapy and chemotherapy. This study investigated molecules synthesized in colorectal cancer cells during hypoxia to explore the possibility of developing molecular probes capable of detecting cell death and/or the efficiency of radiotherapy and chemotherapy.MethodsAt first, we incubated two human colorectal adenocarcinoma cell lines SW480 (UICC stage II) and SW620 (UICC stage III) cells in hypoxic (≤2% O2, 93% N2, and 5% CO2) and normoxic conditions (20% O2, 75% N2, and 5% CO2) for 24 h and 48 h. The relative expression ratio of GLUT1 mRNA in hypoxic conditions was analyzed by RT-PCR. Ten cancerous tissues collected from human colorectal cancer patients were examined. HIF-1α and HIF-2α levels were measured to indicate the degree of hypoxia, and gene expression under hypoxic conditions was determined. As a comparison, HIF-1α, HIF-2α, and GLUT1 levels were measured in the peripheral blood of 100 CRC patients.ResultsHypoxia-induced lactate was found to be elevated 3.24- to 3.36-fold in SW480 cells, and 3.06- to 3.17-fold in SW620 cells. The increased relative expression ratio of GLUT1 mRNA, under hypoxic conditions was higher in SW620 cells (1.39- to 1.72-fold elevation) than in SW480 cells (1.24- to 1.66-fold elevation). HIF-1α and HIF-2α levels were elevated and GLUT1 genes were significantly overexpressed in CRC tissue specimens. The elevated ratio of GLUT1 was higher in stage III and IV CRC tissue specimens than in the stage I and II (2.97–4.73 versus 1.44–2.11). GLUT1 mRNA was also increased in the peripheral blood of stage II and III CRC patients as compared to stage I patients, suggesting that GLUT1 may serve as a hypoxic indicator in CRC patients.ConclusionIn conclusion, this study demonstrated that GLUT1 has the potential to be employed as a molecular marker to indicate the degree of hypoxia experienced by tumors circulating in the blood of cancer patients.

Abstract. The objective of this study was mainly to evaluate the simultaneous detection of expression levels of a multiple mRNA marker panel in the peripheral blood of colorectal cancer (CRC) patients for use in complementary CRC diagnosis. Twenty-seven tumor tissue specimens and 80 peripheral blood specimens were collected from CRC patients. Firstly, the levels of multiple molecular markers in the tumor tissue and blood specimens were evaluated by using real-time quantitative PCR (RT-QPCR) and membrane array. The result of linear regression showed a high degree of correlation (r=0.954, P<0.0001) between the data of these two methods. CK-19 was the marker with the highest detection rate (87.5%) in the peripheral blood, followed by CEA (82.6%), REG4 (80.8%), and then uPA (80.0%) and TLAM1 (80.0%). The levels of the six markers in the peripheral blood were extensively explored. In the 80 patients, the frequency of CK-19, CK-20, CEA, REG4, uPA, and TIAM1 mRNA overexpression was 82.5% (66/80), 78.8% (63/80), 82.5% (66/80), 80.0% (64/80), 78.8% (63/80), and 80.0% (64/80), respectively. Then, a panel combining these 6 mRNA markers was evaluated for its utility in the clinical diagnosis of CRC. The sensitivity, specificity, and accuracy of membrane array-based diagnostic method were 88.8%, 87.8%, and 88.2%, respectively; much higher than those of examinations with single markers. Finally, lymph node metastasis (P=0.024) and TNM stage (P=0.009) were found to be significantly correlated with overexpression of the multiple mRNA marker panel. The detection rates of stage-I and -II CRC by using the multi-marker membrane array were 54.5% (6/11) and 92.0% (23/25), respectively. In conclusion, the results of the present study have shown that this innovative membrane array technique with a multiple mRNA marker panel can significantly improve the diagnosis rate of early colorectal cancer.

Abstract. We investigated gene expressions involved in the glycolytic pathways in colorectal cancer. The study was designed to use gene ontology and its relevant bioinformatics tools to analyze the microarray data obtained from CRC tissues and their corresponding normal tissues, in order to explore the correlation between the glycolytic metabolic pathway and possible pathogenesis of this disease. The overexpression of glycolysis-related genes was observed in over 76% of CRC tissues. In addition, we stimulated the SW480 and SW620 CRC cell lines with 15 mM D-(+)-glucose and 10 mM 2-deoxy-D-glucose respectively. The results indicate that the proliferation response of both the SW480 and SW620 cell lines increased remarkably with a time-dependent effect by D-(+)-glucose administration. In contrast, the proliferation response of both the SW480 and SW620 cell lines was significantly inhibited by 2-DG administration. Likewise, further analyses of the expression of related genes triggered by the D-(+)-glucose in vivo show that the activation process of these eight genes -GLUT1, HK1, GPI, GAPD, PGK1, PGK2, ENO2, PKM2 -prominently increased with a timedependent effect. In conclusion, this study demonstrates that the glycolytic pathway and glycolysis-related genes may play an important role in the tumorigenesis of CRC, but their molecular mechanisms need further investigation to verify this.

Maintaining a high calcium concentration in the endoplasmic reticulum through the action of sarco/endoplasmic reticulum calcium-ATPases (SERCAs) is crucial in many cell functions involved in intracellular signal transduction, control of proliferation, programmed cell death, or the synthesis of mature proteins. Recent studies have found that many SERCAs have altered expression patterns in various malignancies. The purpose of the current study was to quantify the expression of SERCA2 in colorectal cancer (CRC) tissues and the corresponding noncancerous tissues, and to statistically analyze whether the SERCA2 expression levels correlate with the clinico-pathologic features and prognosis of CRC patients. Paired colorectal tissue samples from cancerous and the corresponding noncancerous tissues were obtained from 50 patients who underwent surgical resection. Semiquantitative measurements of SERCA2 messenger RNA (mRNA) expression were done using the multiplex reverse transcriptase-polymerase chain reaction. CRC tissues were analyzed through immunohistochemistry for the SERCA2 protein. SERCA2 mRNA overexpression in cancerous tissues compared with normal counterparts was observed in 45 of 50 (90%) patients. The mean expression level of SERCA2 mRNA in cancerous tissues was significantly higher than that in noncancerous tissues (P = 0.01). Increased SERCA2 protein expression was significantly correlated with serosal invasion (P = 0.012), lymph node metastasis (P = 0.009), and advanced tumor stage (P = 0.004). Furthermore, patients with high SERCA2 expression had a significantly poorer overall survival rate than patients with low SERCA2 (P = 0.032). Multivariate analyses indicated that tumor stage (P = 0.015) and SERCA2 expression were independently correlated with overall survival (P = 0.018). The result of this study indicated that SERCA2 may be a molecular determinant in the development and progression of CRC. The molecular mechanisms underlying the SERCA-dependent calcium accumulation and CRC tumorigenesis are worthy of further investigations.

This is the first comprehensive report to clarify the differential expression profile of whole MAGE family in CRCs, and it might provide some crucial information about the carcinogenesis and progression in Taiwanese patients with CRC.