Transketolase-like protein 1 expression predicts poor prognosis in colorectal cancer

Background: Transketolase-like protein 1 (TKTL1) is an isoform of tranketolase, a key protein in a cancer cell's glucose metabolism that causes rapid cell growth and controls the non-oxidative part of the pentose phosphate pathway (PPP). Its overexpression occurs in several human cancer types. Our purpose was to study whether TKTL1 expression in colorectal cancer tissue associates with these patients’ prognosis. Methods: We collected retrospectively patient data and tissue samples from 840 colorectal cancer patients treated at Helsinki University Hospital, then stained tumor tissue microarrays for TKTL1 by immunohistochemistry, and compared immunohistochemical tissue expression with clinico-pathological parameters and survival. Results: High expression of TKTL1 associated with high Dukes stage, non-mucinous adenocarcinoma, and left-sided disease. Patients with high TKTL1 expression had poorer prognosis than those with low expression, with a 5-year disease-specific survival of 55.7% vs. 62.7%. Conclusion: We show that high TKTL1 in tumor tissue can lead to poor survival in colorectal cancer. TKTL1 thus can serve as a candidate marker for identifying patients at risk of recurrent disease.     

Expression of Cyclooxygenase-1 and –2 and Clinicopathologic Features of Colorectal Cancer in Northern Thailand

Two isoforms of cyclooxygenase, COX-1 and COX-2, have been identified and shown to be involved in ‍tumorigenesis. Although, overexpression of COX-2 in human cancers has been repeatedly reported, no data have ‍hitherto been available for Thai patients. To cast light on the role(s) of COX enzymes in the development and ‍progression of colorectal cancers and to determine the incidence of COX-2 overexpression, the expression levels of ‍COX-1 and COX-2 proteins using Western blot analysis in tumor tissues and adjacent normal tissues obtained from ‍44 Thai patients with colorectal cancer. ‍Compared with paired normal tissues, COX-2 was overexpressed in 13 of 44 colorectal tumor tissues (29.5%). ‍Overall, COX-2 levels in colorectal tumor specimens were significantly correlated with histological differentiation, ‍in particular in the tumors with poor differentiation (p<0.05). In addition, overexpression of COX-2 was found more ‍frequently in colorectal tumors with lymphatic invasion, regional lymph node metastasis and larger size, ‍althoughwithout statistical significance. In contrast to the relatively consistent alteration in COX-2 expression, the ‍level of COX-1 expression was quite varied in tumor tissues. Forty-eight percent of colorectal tumors exhibited a ‍decreased level of COX-1 in comparison to normal tissues and overexpressed in 23%. Thus both isoforms may both ‍play roles in promoting tumorigenesis. However, there was no significant relationship between the alteration of ‍COX-1 protein levels and any pathological features of tumors. ‍     

Lumican expression in advanced colorectal cancer with nodal metastasis correlates with poor prognosis

Lumican is a member of a small leucine-rich proteoglycan family, and it is reportedly overexpressed in human breast cancer. The expression of lumican in the extracellular matrix in breast cancer is associated with a high tumor grade, low estrogen receptor levels and young age. Lumican expression has been previously reported in colorectal cancer, but the role of lumican in the tumor is not well understood. In this study, we examined the expression and role of lumican in advanced colorectal cancer. Immunohistochemical staining was performed on 158 patients who underwent curative surgery for advanced colorectal cancer with lymph node metastasis. In the normal colorectal tissues, lumican immunoreactivity was observed in the fibroblasts and neural cells, but not in the colorectal epithelial cells. Lumican was localized in the cytoplasm of the cancer cells and its overexpression was detected in 99 of the 158 (62.7%) colorectal cancer patients. Clinicopathologically, there was no association of lumican expression with age, sex, histological typing, or venous and lymphatic invasion. However, lumican expression tended to correlate with the spread of lymph node metastasis and the depth of tumor invasion (p=0.136 and 0.135, respectively). Furthermore, the survival rate was significantly lower in patients with a high lumican expression level than in those with a low lumican expression level (p=0.048). These results indicate that lumican expression is a potential prognostic factor in patients with advanced colorectal cancer with nodal metastasis.     

Transketolase‐like protein 1 (TKTL1) is required for rapid cell growth and full viability of human tumor cells

Cancer cells display high rates of aerobic glycolysis, a phenomenon known as the Warburg effect. Lactate and pyruvate, the end products of glycolysis, are overproduced by cancer cells even in the presence of oxygen. The pentose phosphate pathway (PPP) allows glucose conversion to ribose for nucleic acid synthesis, glucose degradation to lactate, and regeneration of redox equivalents. The nonoxidative part of the PPP is controlled by transketolase (TKT) enzymes. One TKT isoform, the transketolase‐like protein 1 (TKTL1) is specifically upregulated in different human cancers and its overexpression predicts a poor patient's survival. This finding implicates that an increased TKTL1 expression may activate the PPP leading to enhanced cancer cell growth and survival. To analyze the functional role of TKTL1 in malignant progression, we inhibited TKTL1 by RNAi technologies in human HCT116 colon carcinoma cells. TKTL1 suppression resulted in a significantly slowed cell growth, glucose consumption and lactate production. In TKTL1 knockdown‐cells, the intracellular reactive oxygen species levels were not significantly increased, whereas the sensitivity towards oxidative stress‐induced apoptosis was clearly enhanced. These data provide new clues on the importance of TKTL1 dys‐regulation in tumor cells and indicate that TKTL1 overexpression may be considered not only as a new tumor marker but also as a good target for anticancer therapy. © 2008 Wiley‐Liss, Inc.     

胸苷磷酸化酶在癌组织中表达的研究

目的　研究胸苷磷酸化酶 (TP)在不同种类癌组织中的表达 ,探讨TP与癌组织血管生成的关系。方法　采用免疫组织化学方法检测 2 5 1例癌组织和相对应的 92例正常组织TP和微血管密度 (MVD)的表达。癌组织包括 :胃癌 4 8例 ,大肠癌 5 3例 ,乳腺癌 4 7例 ,宫颈癌 5 6例 ,肺癌 4 7例 ;正常组织包括 :胃 2 5例 ,大肠 2 5例 ,宫颈 17例 ,肺 2 5例。分析癌组织和正常组织TP表达差异 ,及癌组织TP表达与癌组织MVD的关系。结果　胃癌、大肠癌、乳腺癌、宫颈癌和肺癌的TP表达阳性率分别为6 4 .6 %、6 7.9%、80 .9%、82 .1%和 6 3.8%。癌组织的TP表达阳性率显著高于正常组织 (P =0 .0 0 0 0 )。癌组织TP表达与胃癌、大肠癌、乳腺癌、宫颈癌的MVD值关系密切 (P <0 .0 0 1)。结论　TP在胃癌、大肠癌、乳腺癌、宫颈癌和肺癌组织中过度表达 ,并对胃癌、大肠癌、乳腺癌和宫颈癌的血管生成有明显促进作用。     

Identification of breast cancer-restricted antigens by antibody screening of SKBR3 cDNA library using a preselected patient's serum

Screening of a breast cancer cDNA library from SKBR3 human breast cancer cells by SEREX (serological analysis of cDNA expression library) using a preselected serum from a breast cancer patient revealed 13 genes, two of which, INT-MI-1 and INT-MI-2, encode novel gene products, while the remaining 11 genes and their products are identical with or highly homologous to known GenBank entries. Immunoscreening of the 13 clones using 20 allogeneic sera from breast cancer patients and 20 samples from age- and gender-matched healthy donors showed that lactate dehydrogenase-A (LDH-A), lactate dehydrogenase-B (LDH-B), fibulin-1, and thyroid hormone-binding protein (THBP) were recognized principally by the breast cancer patient sera, indicating the immunogenicity of these molecules in vivo. The other antigens were similarly recognized by normal and patients sera, and thus not tumor-restricted immunologically. RT-PCR analysis revealed strong expression of fibulin-1 in tumor cell lines and surgical specimen whereas in the same experimental conditions, normal tissues scored negative. Also THBP expression was found in various tumors whereas in normal tissues, its expression is restricted to the testis and, at lower levels, in ovary, liver, and spleen. In contrast, LDH-A and LDH-B were ubiquitously expressed in normal and tumor tissues, with LDH-B levels considerably lower and heterogeneous in normal samples compared to those expressed in tumor cell lines. The differential expression of fibulin-1 between the normal tissues and breast carcinoma cell lines (5/6) and surgical specimens (5/6) suggests the possible involvement of the overexpression of this extracellular matrix-associated glycoprotein in the pathogenesis of this neoplasm.     

Tenascin-W, a new marker of cancer stroma, is elevated in sera of colon and breast cancer patients

Tenascins are extracellular matrix proteins present during the development of organisms as well as in pathological conditions. Tenascin-W, the fourth and last member of the tenascin family remains the least well-characterized one. Our study aimed to evaluate the potential significance of tenascin-W as cancer biomarker by monitoring its presence in the serum of colorectal and breast cancer patients and its expression in colorectal tumor tissues. To measure serum tenascin-W levels, a sensitive sandwich-ELISA was established. Mean tenascin-W concentration in sera of patients with nonmetastatic colorectal cancer at time of diagnosis was highly increased compared to that of healthy volunteers. A similar tendency was observed for tenascin-C in the same patient cohort. However, the increase was much more striking for tenascin-W. We also detected elevated tenascin-W levels in sera of breast cancer patients. Furthermore, we could show a prominent expression of tenascin-W in extracts from colorectal tumor tissues by immunoblot analysis, whereas tenascin-W was not detectable in the corresponding normal colon mucosa. To confirm the western blot results, we performed immunohistochemistry of frozen sections of the same patients as well as of an additional, independently chosen collection of colorectal cancer tissues. In all cases, similarly to tenascin-C, tenascin-W was detected in the tumor stroma. Our results reveal a clear association between elevated levels of tenascin-W and the presence of cancer. These results warrant further studies to evaluate the potential value of serum and tissue tenascin-W levels as diagnostic, prognostic or monitoring biomarker in colorectal, breast and possibly other solid cancers.     

Cytoplasmic HuR expression correlates with P-gp, HER-2 positivity, and poor outcome in breast cancer

HuR is an ubiquitously expressed RNA-binding protein that stabilizes messenger RNA and regulates translation. This protein has been shown to play an important role in carcinogenesis and cancer progression. P-glycoprotein (P-gp) is the product of the multidrug resistance 1 gene, and the overexpression of P-gp induces multidrug resistance and represents a major obstacle in cancer chemotherapy. The purpose of this study was to determine the expression of HuR and P-gp in human breast cancer tissues and analyze the relationship between HuR or P-gp expression and the clinical–pathological variables and patient outcomes. Immunohistochemistry was used to determine HuR and P-gp expression in 82 human breast cancer tissues and 20 matched adjacent noncancerous tissues. Additionally, 16 benign breast tumor samples were used as controls. The overexpression of cytoplasmic HuR was found in breast cancer but not in the matched adjacent noncancerous tissues or benign breast tumors. The expression levels of cytoplasmic HuR were significantly associated with increased age, high nuclear grade, and the positive expression of the ER, PR, and HER-2/neu. HuR was also associated with the expression of P-gp protein. Furthermore, univariate analysis indicates that patients with high expression levels of cytoplasmic HuR or P-gp had significantly reduced survival compared to patients with low expression levels. A multivariate analysis showed that age at diagnosis, nuclear grade, and cytoplasmic HuR positivity were independent indicators for disease-free survival and overall survival in patients with breast cancer. In conclusion, cytoplasmic HuR expression detected by immunohistochemical staining is a negative prognostic indicator for survival in patients with breast cancer.     

Down-regulation of miR-126 expression in colorectal cancer and its clinical significance

MicroRNAs (miRNAs) are non-coding RNAs that regulate the expression of target mRNAs. Altered expression of specific miRNAs in several tumor types has been reported. However, the expression levels of miR-126 in colorectal cancers are unclear. In this study, we compared the expression of miR-126 between colorectal cancer tissues and non-tumor tissues. The expression levels of miR-126 in colorectal cancer tissues were significantly lower than those in non-tumor tissues, and miR-126 overexpression inhibited the growth of colorectal cancer cells. This new information may help to clarify the molecular mechanisms involved in colorectal carcinogenesis and to indicate that miR-126 may be a novel suppressive microRNA and help to differentiate between malignant and normal colorectal tissue.     

The significance of placenta growth factor in angiogenesis and clinical outcome of human gastric cancer

Placenta growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family of proangiogenic factors and its overexpression has been linked to pathological angiogenesis. We studied the relationship between the expression of PlGF and VEGF in human gastric cancer tissues and microvessel density (MVD), as well as clinical outcome in 79 patients with gastric cancer by using an enzyme immunoassay for PlGF and VEGF expression levels in gastric cancers and surrounding non-cancerous mucosa. PlGF protein levels were significantly higher in tumor than in the corresponding non-tumorous mucosa (median value 48.5 vs 9.8 pg/mg, P < 0.001). In contrast, VEGF protein levels were not (66.7 vs 80.7 pg/mg, P = 0.522). VEGF expression level was not significantly correlated with MVD, patient survival, and clinicopathological factors except Lauren classification in this study. PlGF may be an important angiogenic factor in human gastric cancer, and PlGF expression level was significantly correlated with serosal invasion, positive lymph node metastases, tumor stages, and patient survival.     

Overexpression of cyclinD1 predicts for poor prognosis in estrogen receptor-negative breast cancer patients

CyclinD1 plays a critical role in regulating cell cycle progression. CyclinD1 mRNA and protein are overexpressed in approximately 50% of primary breast cancer cases. However, its clinical significance as a predictive factor remains unclear. One hundred and seventy-three female patients diagnosed with invasive ductal carcinoma who had undergone a mastectomy (161 patients) or breast-conserving surgery (12 patients) were followed up for 6-119 months (median 86 months) postoperatively. Immunoreactivity for monoclonal anti-cyclinD1 antibody (clone DCS-6) with paraffin-embedded carcinoma tissues was investigated using a labeled streptavidin-biotin method. Overexpression of cyclinD1 was found in 42% (73 of 173), and strongly correlated with estrogen receptor (ER) expression (p < 0.000001). Univariate analysis revealed no association between overexpression of cyclinD1 and overall survival or relapse-free survival in all patient groups. However, in the ER-negative subgroup (n = 75), overexpression of cyclinD1 was significantly correlated with shorter overall survival (p = 0.018) and relapse-free survival (p = 0.014) as well as the lymph node status and tumor size. In contrast, there were no significant associations between overexpression of cyclinD1 and clinical outcome in the ER-positive subgroup. According to Cox's multivariate analysis in the ER-negative subgroup, overexpression of cyclinD1 had the most significant effect on overall survival (p = 0.02) and relapse-free survival (p = 0.0058), followed by nodal status and histologic grade. These findings suggest that overexpression of cyclinD1 is an independent prognostic indicator in ER-negative breast cancer patients.     

Aurora-A mt-P53和c-myc在大肠癌中的表达及意义

  目的  研究中心体相关激酶Aurora-A、突变型P53(mt-P53)和c-myc在大肠癌中的表达规律, 探讨其相互关系及在肿瘤发生发展中的作用。  方法  应用组织芯片和免疫组织化学技术(SP法)检测Aurora-A、mt-P53和c-myc在130例大肠癌、癌旁组织和正常大肠组织中的表达, 并结合临床病理学参数进行综合分析。  结果  Aurora-A在正常大肠组织、癌旁组织和大肠癌中的阳性表达率分别为0, 35%, 69%。mt-P53分别为0, 20%, 57%。c-myc分别为0, 37%, 76%。与正常大肠组织和癌旁相比, 癌组织中Aurora-A、mt-P53和c-myc的表达明显升高(P < 0.01);三者的表达与肿瘤的浸润程度有关(P < 0.05), mt-P53和c-myc还与Dukes'分期和淋巴结转移关系密切(P < 0.05)。在大肠癌中Aurora-A的阳性表达与mt-P53、c-myc的阳性表达呈显著正相关(分别为r=0.362, P < 0.01;r=0.487, P < 0.01), mt-P53和c-myc之间也存在显著正相关(r=0.242, P < 0.01)。  结论  Aurora-A和c-myc蛋白的过表达与P53的突变在大肠癌的发生、侵袭和转移中发挥着重要作用。综合分析Aurora-A、mt-P53和c-myc蛋白的表达对大肠癌的早期诊断及预后判断具有重要价值。      

Human breast cancer cell metastasis is attenuated by lysyl oxidase inhibitors through down-regulation of focal adhesion kinase and the paxillin-signaling pathway

The extracellular matrix (ECM) plays a critical role in the development and invasion of primary breast tumors. Lysyl oxidase (LOX), which is an ECM remodeling enzyme, appears to play roles in promoting cancer cell motility and invasion. To ascertain whether LOX overexpression in breast tumor tissues from Asian patients is associated with decreases in metastasis-free and overall survival in breast cancer patients, the mRNA levels of LOX were examined in paired tumor/normal tissue samples using real-time RT-PCR analysis (n = 246 pair-matched samples). To test whether specifically targeting LOX by inhibiting its activity (using beta-aminopropionitrile (β-APN), a LOX inhibitor), mRNA expression (using siRNA), or protein expression (using 25 μM magnolol) attenuates the invasion of MDA-MB-231 breast cancer cells, a cancer cell migration assay was performed. Interestingly, only 78.5% (n = 193) of the breast cancer tumors displayed detectable LOX expression. Nearly 60% (n = 120) of the cases fell into Group 1 (tumor > normal, T > N); in this group, the mean LOX expression in the tumor cells was 20.2-fold greater than in normal cells. However, in Group 2 (normal > tumor, N > T), the LOX expression level in most of the normal tissues examined (80%, 59/73) was less than fivefold greater than in the tumor tissues. The increased level of active LOX in the invasive breast cancer cell line MDA-MB-231 was accompanied by the increased phosphorylation of focal adhesion kinase at Tyr-576 and of paxillin at Tyr-118. We also found that the addition of β-APN (300 μM) and magnolol (25 μM), synergistically inhibited the migration and invasion of MDA-MB-231 cells. In this article, we describe, for the first time, higher expression of a LOX protein in breast tumors compared with normal tissues from Asian patients. Moreover, the results indicate that the inhibition of LOX using magnolol may represent a more desirable strategy for breast cancer therapy than the use of β-APN.     

Y-box factor YB-1 predicts drug resistance and patient outcome in breast cancer independent of clinically relevant tumor biologic factors HER2, uPA and PAI-1.

Intrinsic or acquired resistance to chemotherapy is responsible for failure of current treatment regimens in breast cancer patients. The Y-box protein YB-1 regulates expression of the P-glycoprotein gene mdr1, which plays a major role in the development of a multidrug-resistant tumor phenotype. In human breast cancer, overexpression and nuclear localization of YB-1 is associated with upregulation of P-glycoprotein. In our pilot study, we analyzed the clinical relevance of YB-1 expression in breast cancer (n = 83) after a median follow-up of 61 months and compared it with tumor-biologic factors already used for clinical risk-group discrimination, i.e., HER2, urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1). High YB-1 expression in tumor tissue and surrounding benign breast epithelial cells was significantly associated with poor patient outcome. In patients who received postoperative chemotherapy, the 5-year relapse rate was 66% in patients with high YB-1 expression. In contrast, in patients with low YB-1 expressions, no relapse has been observed so far. YB-1 expression thus indicates clinical drug resistance in breast cancer. Moreover, YB-1 correlates with breast cancer aggressiveness: in patients not treated with postoperative chemotherapy, those with low YB-1 expression are still free of disease, whereas the 5-year relapse rate in those with high YB-1 was 30%. There was no significant correlation between YB-1 expression and either HER2 expression or uPA and PAI-1 levels. Risk-group assessment achieved by YB-1 differed significantly from that by HER2 or uPA/PAI-1. In conclusion, YB-1 demonstrated prognostic and predictive significance in breast cancer by identifying high-risk patients in both the presence and absence of postoperative chemotherapy, independent of tumor-biologic factors currently available for clinical decision making.