Endogenously elevated bilirubin modulates kidney function and protects from circulating oxidative stress in a rat model of adenine-induced kidney failure

Mildly elevated bilirubin is associated with a reduction in the presence and progression of chronic kidney disease and related mortality, which may be attributed to bilirubin's antioxidant properties. This study investigated whether endogenously elevated bilirubin would protect against adenine-induced kidney damage in male hyperbilirubinaemic Gunn rats and littermate controls. Animals were orally administered adenine or methylcellulose solvent (vehicle) daily for 10 days and were then monitored for 28 days. Serum and urine were assessed throughout the protocol for parameters of kidney function and antioxidant/oxidative stress status and kidneys were harvested for histological examination upon completion of the study. Adenine-treated animals experienced weight-loss, polyuria and polydipsia; however, these effects were significantly attenuated in adenine-treated Gunn rats. No difference in the presence of dihydroadenine crystals, lymphocytic infiltration and fibrosis were noted in Gunn rat kidneys versus controls. However, plasma protein carbonyl and F2-isoprostane concentrations were significantly decreased in Gunn rats versus controls, with no change in urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine or kidney tissue F2-isoprostane concentrations. These data indicated that endogenously elevated bilirubin specifically protects from systemic oxidative stress in the vascular compartment. These data may help to clarify the protective relationship between bilirubin, kidney function and cardiovascular mortality in clinical investigations.

Cancer stem cells in oesophageal squamous cell carcinoma: Identification, prognostic and treatment perspectives

Cancer stem cells (CSCs) are a vital subpopulation of cells to target for the treatment of cancers. In oesophageal squamous cell carcinoma (ESCC), there are several markers such as CD44, ALDH, Pygo2, MAML1, Twist1, Musashi1, Side population (SP), CD271 and CD90 that have been proposed to identify the cancer stem cells in individual cancer masses. It has also been demonstrated that stem cell markers like ALDH1, HIWI, Oct3/4, ABCG2, SOX2, SALL4, BMI-1, NANOG, CD133 and podoplanin are associated with patient's prognosis, pathological stages, cancer recurrence and therapy resistance. Finding new cancer stem cell targets or designing drugs to manipulate the known molecular targets in CSCs could be useful for improvements in clinical outcomes of the disease. To conclude, data suggest that CSCs in oesophageal squamous cell carcinoma are related to resistance to therapy and poor prognosis of patients with ESCC. Therefore, innovative insights into CSC biology and CSC-targeted therapies will help to achieve more effective management of patients with oesophageal squamous cell carcinoma.

Cancer stem cell: fundamental experimental pathological concepts and updates

Cancer stem cells (CSCs) are a subset of cancer cells which play a key role in predicting the biological aggressiveness of cancer due to its ability of self-renewal and multi-lineage differentiation (stemness). The CSC model is a dynamic one with a functional subpopulation of cancer cells rather than a stable cell population responsible for tumour regeneration. Hypotheses regarding the origins of CSCs include (1) malignant transformation of normal stem cells; (2) mature cancer cell de-differentiation with epithelial-mesenchymal transition and (3) induced pluripotent cancer cells. Surprisingly, the cancer stem cell hypothesis originated in the late nineteenth century and the existence of haematopoietic stem cells was demonstrated a century later, demonstrating that the concept was possible. In the last decade, CSCs have been identified and isolated in different cancers. The hallmark traits of CSCs include their heterogeneity, interaction with microenvironments and plasticity. Understanding these basic concepts of CSCs is important for translational applications using CSCs in the management of patients with cancer.

Abstract 549: Gene expression changes of GAEC1 in a large cohort of human cancer tissues

Background: Gene amplified in esophageal cancer 1 (GAEC1) is a novel oncogene located at 7q22.1 and preliminary work on GAEC1 suggested that it has tumorigenic potential and over expression of GAEC1 is a critical step for carcinogenesis. However, because the initial work on this gene was undertaken in its oncogenic properties, there is currently a lack of information of the molecular roles of this novel gene in other cancers. This research is intended to investigate the expression pattern of GAEC1 mRNA in tissues and cell line models of cancer.

Materials and methods: Approximately 856 human tissues and blood samples have been collected. This comprises 430 colorectal tissues 135 oesophageal tissues 254 thyroid tissues; 37 blood samples (25 oesophageal cancers and 12 healthy individuals). This study used nine cancer (oesophageal, colorectal and thyroid cancers) and two normal (oesophageal epithelial and colon epithelial cell line) cell lines. Histological samples (non-tumour, pre-cancerous and cancerous lesions) were collected and the pathology of these lesions were reviewed. The mRNAs of the selected samples were extracted by standard protocol. GAEC1 mRNA expression was studied by evaluating the quantitative amplification of GAEC1 RNA using quantitative real-time polymerase chain reaction.

Results: GAEC1 mRNA expression levels were significantly altered in all selected cancer tissue models (colorectal, oesophageal and thyroid carcinomas). This level of GAEC1 was associated with tumour site, histological subtypes, and metastasis. At the mRNA level, 29% (n=61/210) of colorectal cancers, 22% (n=23/105)of oesophageal cancers and 7% (n=8/120) of thyroid cancers showed high GAEC1 expression (relative to control tissue). GAEC1 mRNA expression (mean) in oesophageal cancer blood samples showed 4 times higher expression compared to the control samples (p < 0.0001). Patients with high GAEC1 mRNA expression levels in their oesophageal cancer tissue had reduced survival period compared to patients with low GAEC1 mRNA levels (p=0.05).

Conclusion: The current study noted multiple new findings, including relationships with clinical and pathological parameters with GAEC1 mRNA expression in three different types of cancers. The altered mRNA expression of GAEC1 and its correlation with different tissues samples and sites of tumour may also be important for the development of gene targeting therapies for cancers. Further research in unveiling GAEC1 protein structure and functional studies and post translational modifications will help in understanding the role of this oncogene in human carcinogenesis. Results of this study indicate that GAEC1 has an impact on human cancer pathogenesis.

Citation Format: Vinod Gopalan, Robert A. Smith, Suja Pillai, Ali Salajegheh, Johnny Chuek-on Tang, Alfred KY Lam. Gene expression changes of GAEC1 in a large cohort of human cancer tissues. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 549. doi:10.1158/1538-7445.AM2014-549

Abstract 528: The modulatory role of miRNA 126 in thyroid cancer angiogenesis

MicroRNAs (miRNAs) have been described as one of the novel class of molecular regulators. Due to the crucial role miRNA-126 plays in angiogenesis, as well as the necessity of angiogenesis in malignancy, miRNA-126 has been found in association with several types of cancer.

Vascular endothelial growth factor (VEGF) promotes angiogenesis and is a potent mediator of vascular permeability, as well as being a key mediator of tumour-associated neoangiogenesis and progression.

In this study, we have investigated the role of miRNA-126, VEGF-A and their impact on angiogenesis in thyroid cancers.

51 conventional papillary thyroid carcinomas, 37 follicular variant of papillary thyroid carcinomas, 13 undifferentiated thyroid carcinomas, 13 matched lymph nodes metastasis and 21 normal thyroid tissues obtained from non-cancer adjacent to benign lesions were recruited as controls.

Firstly, extracted miRNAs from selected samples were loaded on a miRNA microarray chip developed by Agilent (Agilent Technologies, Inc., Santa Clara, CA, USA) using a pooling method to confirm the expression differences of miRNAs including miRNA-126. Then, miRNA-126 and VEGF-A was tested in individual samples using real-time PCR. In addition, 2 papillary thyroid cancer cell lines (K1 and B-CPAP) and a normal thyroid cell line (Nthy-ori 3-1) were used for the exogenous manipulation of the miRNA-126 and investigation of its effect on VEGF-A expression. The expression of VEGF-A were then measured by immunofluorescence and western blot techniques.

The expression of miRNA-126 was noticeably higher in the pool of papillary thyroid carcinoma with metastasis. Using real time PCR, miRNA-126 and VEGF-A were significantly over-expressed in cancer populations compared to controls (p=0.009 and 0.011 respectively). A significant positive correlation between miRNA-126 and VEGF-A expression was also noted (p= 0.00009).

Real time PCR of extracted RNA from the cell lines has shown under-expression of miRNA-126 compared to normal cells while VEGF-A RNA and protein were over-expressed. The reduction of VEGF-A protein expression after transfection of miRNA-126 mimic into K1 and B-CPAP, confirms the regulatory role of miRNA-126 on VEGF-A expression in thyroid cancer cell lines.

These findings add weight to our previous understanding about the angiogenic role of miRNA-126 in cancer. These experiments provide information on the functional consequences of VEGF manipulation via miRNA on cancer. The data will provide primary information regarding the utility of over-expressing miRNA-126 in cancer management and future development of effective tumour-specific anti-angiogenic therapy.

Citation Format: Ali Salajegheh, Haleh Vosgha, Md. Atiqur Rahman, Vinod Gopalan, Robert Anthony Smith, Alfred King-Yin Lam. The modulatory role of miRNA 126 in thyroid cancer angiogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 528. doi:10.1158/1538-7445.AM2014-528

The roles of JK-1 (FAM134B) expressions in colorectal cancer

The aims of the present study are to investigate the clinicopathological correlations of JK-1(FAM134B) expression and its relationship to carcinogenesis in a colorectal adenoma-adenocarcinoma model. JK-1(FAM134B) protein expression was studied in a colon cancer cell line by Western blot and immunocytochemistry. JK-1(FAM134B) expression profiles at mRNA and protein levels were investigated in cancer tissues from 236 patients with colorectal adenocarcinoma and 32 patients with colorectal adenoma using real-time polymerase chain reaction and immunohistochemistry. The findings were then correlated with the clinicopathological features of these tumours. JK-1(FAM134B) protein was demonstrated in the colon cancer cells by Western blot. The protein was located in the nuclei of the tumour cells at both cellular and tissue levels. In colorectal adenocarcinomas, lower levels of JK-1(FAM134B) protein expression were associated with younger age (p=0.032), larger tumour size (p=0.004), advanced cancer stages (p=0.016) and higher rates of cancer recurrence (p=0.04). Also, lower levels of JK-1(FAM134B) mRNA expression were associated with advanced cancer stages (p=0.02) and presence of lymphovascular invasion (p=0.014). Higher JK-1(FAM134B) mRNA and protein expression levels were identified in adenomas and non-neoplastic mucosae, compared to carcinomas (p=0.005). To conclude, JK-1(FAM134B) mRNA expression and JK1 (FAM134B) protein levels varied with the different stages of progression of colorectal tumours. The expression levels of the gene were associated with clinicopathological features in patients with colorectal adenocarcinoma suggesting that JK-1(FAM134B) gene has roles in controlling some steps in the development of the invasive phenotypes from colorectal adenoma to early staged as well as advanced staged colorectal adenocarcinomas.

JK1 (FAM134B) gene and colorectal cancer: a pilot study on the gene copy number alterations and correlations with clinicopathological parameters

AIMS

The aims of the study are to characterize changes in JK-1 (FAM134B) at the DNA level in colorectal adenocarcinoma and adenoma and exploring the possible correlations with clinical and pathological features.

METHOD

JK-1 gene DNA copy number changes were studied in 211 colorectal carcinomas, 32 colorectal adenoma and 20 colorectal non-cancer colorectal tissue samples by real-time quantitative polymerase chain reaction. The results were correlated with clinical and pathological parameters.

RESULTS

Colorectal adenomas were more likely to be amplified than deleted with regard to JK-1 (FAM134B) DNA copy number change. The copy number level of JK-1 (FAM134B) DNA in colorectal adenocarcinomas was significantly lower in comparison to colorectal adenomas. Changes in JK-1 (FAM134B) DNA copy number were associated with histological subtypes, and cancer stage. Lower copy numbers were associated with higher tumor stage, lymph node stage and overall pathological stage of cancer. Conversely, higher DNA copy numbers were detected more often in the mucinous adenocarcinoma.

CONCLUSIONS

This is the first study showing significant correlations of the JK-1 (FAM134B) gene copy number alterations with clinical and pathological features in a large cohort of pre-invasive and invasive colorectal malignancies. The changes in DNA copy number associated with progression of colorectal malignancies reflect that JK-1 (FAM134B) gene could play a role in controlling some steps in development of the invasive phenotypes.

Expression profile of endothelin 1 and its receptor endothelin receptor A in papillary thyroid carcinoma and their correlations with clinicopathologic characteristics

The endothelin axis is a group of signaling molecules and their receptors that have been implicated in vascularization of cancers, with their expression being observed to change in different cancer types. In this research, we examined the expression of endothelin 1 and endothelin receptor A at the protein and messenger RNA (mRNA) levels in 123 papillary thyroid carcinomas and 40 matched lymph nodes with metastatic papillary thyroid carcinomas. We found altered endothelin axis mRNA expression in several clinicopathologic parameters with increased endothelin 1 expression in thyroid papillary carcinoma showing stromal calcification, cancers in men, and primary cancers with lymph node metastases. Increased endothelin receptor A mRNA expression was noted in the larger cancers. There is a significant correlation between expression of endothelin receptor A and endothelin 1 in papillary thyroid carcinoma. Both endothelin receptor A and endothelin 1 mRNA expressions were significantly higher in metastatic carcinoma in the lymph node than in primary thyroid cancer. The metastatic carcinoma in the lymph node had increased expression compared with matched primary thyroid carcinoma. Expressions of endothelin 1 and endothelin receptor A were also documented as being high at the protein level. Our results indicate that in thyroid cancer, endothelin 1 and endothelin receptor A are associated with growth in advanced stages and lymph node metastases, likely through known angiogenic linkages. Targeting the endothelin axis may be useful in planning angiogenesis therapy for thyroid cancer.

Regulation of microRNA-1288 in colorectal cancer: altered expression and its clinicopathological significance

We aim to examine the miR-1288 expression in cancer cell lines and a large cohort of patients with colorectal cancer. Two colon cancer cell lines (SW480 and SW48) and one normal colonic epithelial cell line (FHC) were recruited. The miRNA expressions of miR-1288 were tested on these cell lines by using quantitative real-time polymerase chain reaction (qRT-PCR). An exogenous miR-1288 (mimic) was used to detect cell proliferation and cell cycle changes in SW480 using MTT calorimetric assay and flow cytometry, respectively. In addition, tissues from 122 patients with surgical resection of colorectum (82 adenocarcinomas, 20 adenomas, and 20 non-neoplastic tissues) were tested for miR-1288 expression by qRT-PCR. The colon cancer cell lines showed reduced expression of miR-1288 compared to normal colonic epithelial cell line. Over expression of miR-1288 in SW480 cell line showed increased cell proliferation and increased G2-M phase cells. In tissues, reduced miR-1288 expression was noted in majority of colorectal adenocarcinoma compared to colorectal adenoma and non-neoplastic tissues. Reduced or absent expression of miR-1288 was noted in 76% (n = 62/82) of the cancers. The expression levels of miR-1288 were higher in distal colorectal adenocarcinomas (P = 0.013) and in cancers of lower T staging (P = 0.033). To conclude, alternation of miR-1288 expression is important in the progression of colorectal cancer. The differential regulation of miR-1288 was found to be related to cancer location and pathological staging in colorectal cancers.

Clinical impacts of mammalian target of rapamycin expression in human colorectal cancers

This study investigated the clinicopathologic roles of mammalian target of rapamycin (mTOR) expression and its relationship to carcinogenesis and tumor progression in a colorectal adenoma-adenocarcinoma model. Two colon cancer cell lines with different pathologic stages (SW480 and SW48) and 1 normal colonic epithelial cell line (FHC) were used, in addition to 119 colorectal adenocarcinomas and 32 adenomas. mTOR expression profiles at messenger RNA (mRNA) and protein levels were investigated in the cells and tissues using real-time quantification polymerase chain reaction and immunohistochemistry. The findings were correlated with the clinicopathologic features of the tumors. The colon cell line from stage III cancer (SW48) showed higher expression of mTOR mRNA than that from stage II cancer (SW480). At the tissue level, mTOR showed higher mRNA and protein expression in colorectal carcinoma than in adenoma. The mRNA and protein expression was correlated with each other in approximately one-third of the carcinomas and adenomas. High levels of mTOR mRNA expression were noted more in carcinoma or adenoma arising from the distal portion of the large intestine (P = .025 and .019, respectively). Within the colorectal cancer population, a high level of expression of mTOR mRNA was related to the presence of lymph node metastases (P = .031), advanced pathologic stage (P = .05), and presence of persistent disease or tumor recurrence (P = .035). To conclude, the study has indicated that mTOR is likely to be involved in the development and progression of colorectal cancer and is linked to cancer initiation, invasiveness, and progression.