Marjolein H.F.M. Lentjes

N-Myc Downstream-Regulated Gene 4 (NDRG4): A Candidate Tumor Suppressor Gene and Potential Biomarker for Colorectal Cancer

BACKGROUND Identification of hypermethylated tumor suppressor genes in body fluids is an appealing strategy for the noninvasive detection of colorectal cancer. Here we examined the role of N-Myc downstream-regulated gene 4 (NDRG4) as a novel tumor suppressor and biomarker in colorectal cancer. METHODS NDRG4 promoter methylation was analyzed in human colorectal cancer cell lines, colorectal tissue, and noncancerous colon mucosa by using methylation-specific polymerase chain reaction (PCR) and bisulfite sequencing. NDRG4 mRNA and protein expression were studied using real-time-PCR and immunohistochemistry, respectively. Tumor suppressor functions of NDRG4 were examined by colony formation, cell proliferation, and migration and invasion assays in colorectal cancer cell lines that were stably transfected with an NDRG4 expression construct. Quantitative methylation-specific PCR was used to examine the utility of NDRG4 promoter methylation as a biomarker in fecal DNA from 75 colorectal cancer patients and 75 control subjects. All P values are two-sided. RESULTS The prevalence of NDRG4 promoter methylation in two independent series of colorectal cancers was 86% (71/83) and 70% (128/184) compared with 4% (2/48) in noncancerous colon mucosa (P < .001). NDRG4 mRNA and protein expression were decreased in colorectal cancer tissue compared with noncancerous colon mucosa. NDRG4 overexpression in colorectal cancer cell lines suppressed colony formation (P = .014), cell proliferation (P < .001), and invasion (P < .001). NDRG4 promoter methylation analysis in fecal DNA from a training set of colorectal cancer patients and control subjects yielded a sensitivity of 61% (95% confidence interval [CI] = 43% to 79%) and a specificity of 93% (95% CI = 90% to 97%). An independent test set of colorectal cancer patients and control subjects yielded a sensitivity of 53% (95% CI = 39% to 67%) and a specificity of 100% (95% CI = 86% to 100%). CONCLUSIONS NDRG4 is a candidate tumor suppressor gene in colorectal cancer whose expression is frequently inactivated by promoter methylation. NDRG4 promoter methylation is a potential biomarker for the noninvasive detection of colorectal cancer in stool samples.

GATA4 and GATA5 are Potential Tumor Suppressors and Biomarkers in Colorectal Cancer

Purpose: The transcription factors GATA4 and GATA5 are involved in gastrointestinal development and are inactivated by promoter hypermethylation in colorectal cancer. Here, we evaluated GATA4/5 promoter methylation as potential biomarkers for noninvasive colorectal cancer detection, and investigated the role of GATA4/5 in colorectal cancer. Experimental Design: Promoter methylation of GATA4/5 was analyzed in colorectal tissue and fecal DNA from colorectal cancer patients and healthy controls using methylation-specific PCR. The potential function of GATA4/5 as tumor suppressors was studied by inducing GATA4/5 overexpression in human colorectal cancer cell lines. Results:GATA4/5 methylation was observed in 70% (63/90) and 79% (61/77) of colorectal carcinomas, respectively, and was independent of clinicopathologic features. Methylation frequencies in normal colon tissues from noncancerous controls were 6% (5 of 88, GATA4; P < 0.001) and 13% (13 of 100, GATA5; P < 0.001). GATA4/5 overexpression suppressed colony formation (P < 0.005), proliferation (P < 0.001), migration (P < 0.05), invasion (P < 0.05), and anchorage-independent growth (P < 0.0001) of colorectal cancer cells. Examination of GATA4 methylation in fecal DNA from two independent series of colorectal cancer patients and controls yielded a sensitivity of 71% [95% confidence interval (95% CI), 55-88%] and specificity of 84% (95% CI, 74–95%) for colorectal cancer detection in the training set, and a sensitivity of 51% (95% CI, 37–65%) and specificity of 93% (95% CI, 84-100%) in the validation set. Conclusions: Methylation of GATA4/5 is a common and specific event in colorectal carcinomas, and GATA4/5 exhibit tumor suppressive effects in colorectal cancer cells in vitro. GATA4 methylation in fecal DNA may be of interest for colorectal cancer detection.

Methylation-Specific PCR Unraveled

Methylation‐specific PCR (MSP) is a simple, quick and cost‐effective method to analyze the DNA methylation status of virtually any group of CpG sites within a CpG island. The technique comprises two parts: (1) sodium bisulfite conversion of unmethylated cytosines to uracil under conditions whereby methylated cytosines remains unchanged and (2) detection of the bisulfite induced sequence differences by PCR using specific primer sets for both unmethylated and methylated DNA. This review discusses the critical parameters of MSP and presents an overview of the available MSP variants and the (clinical) applications.

Meat consumption and K-ras mutations in sporadic colon and rectal cancer in The Netherlands Cohort Study

Case–cohort analyses were performed on meat and fish consumption in relation to K-ras mutations in 448 colon and 160 rectal cancers that occurred during 7.3 years of follow-up, excluding the first 2.3 years, and 2948 subcohort members of The Netherlands Cohort Study on diet and cancer. Adjusted incidence rate ratios and 95% confidence intervals were computed for colon and rectal cancer and for K-ras mutation status subgroups. Total fresh meat, most types of fresh meat and fish were not associated with colon or rectal cancer, neither overall nor with K-ras mutation status. However, several weak associations were observed for tumours with a wild-type K-ras, including beef and colon tumours, and an inverse association for pork with colon and rectal tumours; for meat products, an increased association was observed with wild-type K-ras tumours in the colon and possibly with G>A transitions in rectal tumours.

The emerging role of GATA transcription factors in development and disease.

The GATA family of transcription factors consists of six proteins (GATA1-6) which are involved in a variety of physiological and pathological processes. GATA1/2/3 are required for differentiation of mesoderm and ectoderm-derived tissues, including the haematopoietic and central nervous system. GATA4/5/6 are implicated in development and differentiation of endoderm- and mesoderm-derived tissues such as induction of differentiation of embryonic stem cells, cardiovascular embryogenesis and guidance of epithelial cell differentiation in the adult.

Dietary folate intake and k-ras mutations in sporadic colon and rectal cancer in The Netherlands Cohort Study.

We studied the association between dietary folate and specific K‐ras mutations in colon and rectal cancer in The Netherlands Cohort Study on diet and cancer. After 7.3 years of follow‐up, 448 colon and 160 rectal cancer patients and 3,048 sub‐cohort members (55–69 years at baseline) were available for data analyses. Mutation analysis of the K‐ras gene was carried out on all archival adenocarcinoma specimens. Case–cohort analyses were used to compute adjusted incidence rate ratios (RR) and 95% confidence intervals (CI) for colon and rectal cancer overall and for K‐ras mutation status subgroups according to 100 μg/day increased intake in dietary folate. Dietary folate intake was not significantly associated with colon cancer risk for men or women, neither overall nor with K‐ras mutation status. For rectal cancer, folate intake was associated with a decreased disease risk in men and was most pronounced for K‐ras mutated tumors, whereas an increased association was observed for women. Regarding the K‐ras mutation status in women, an increased association was observed for both wild‐type and mutated K‐ras tumors. Specifically, folate intake was associated with an increased risk of G>T and G>C transversions in rectal tumors (RR = 2.69, 95% CI = 1.43–5.09), but inversely associated with G>A transitions (RR = 0.08, 95% CI = 0.01–0.53). Our data suggest that the effect of folate on rectal cancer risk is different for men and women and depends on the K‐ras mutation status of the tumor.

Methylation-associated dysregulation of the suppressor of cytokine signaling-3 gene in multiple myeloma

The family of suppressor of cytokine signaling (SOCS) proteins negatively regulates cytokine signaling in different cellular pathways including interleukin-6 (IL-6). Since IL-6 plays an essential role in regulating growth and survival of multiple myeloma (MM) cells, methylation-associated dysregulation of SOCS3 may contribute to the malignant phenotype of MM cells. We used methylation-specific PCR (MSP) to assess the methylation status of the SOCS3 CpG island in five MM cell lines and 70 patient samples. Additional bisulfite sequencing and RNA expression analysis using reverse transcriptase polymerase chain reaction was performed in two cell lines. We identified aberrant SOCS3 methylation in 3/5 MM cell lines. Methylation of SOCS3 in cell lines was associated with transcriptional downregulation. Treatment of OPM-2 cells, which carry a methylated SOCS3 gene, with the demethylating agent 5-aza-2’-deoxycytidine restored SOCS3 expression in association with partial demethylation. In patient samples with malignant plasma cell disorders, SOCS3 was methylated in 5/70 (7.1 %) cases, while there was no aberrant SOCS3 methylation in normal peripheral blood and non-malignant bone marrow cells. We found an association of SOCS3 methylation with extramedullary manifestations (p = 0.03), plasma cell leukemia (p = 0.003), elevated LDH (p = 0.001), increased creatinine ( p = 0.01) and remarkably shortened survival (6.9 vs. 56.1 months, HR 5.9, p = 0.0007). Our findings reveal a novel epigenetic event possibly implicated in the pathogenesis of MM and representing a potential prognostic biomarker. Epigenetic dysregulation of the SOCS3 gene may interfere with the cellular response to the complex cytokine network thus supporting survival and expansion of MM cells.

Mitochondrial DNA copy number in colorectal cancer: between tissue comparisons, clinicopathological characteristics and survival

Low mitochondrial DNA (mtDNA) copy number in tumors has been associated with worse prognosis in colorectal cancer (CRC). This study further deciphers the role of mtDNA copy number in CRC by comparing mtDNA copy number between healthy, adenoma and carcinoma tissue, by investigating its association according to several clinicopathological characteristics in CRC, and by relating it to CRC-specific survival in CRC patients. A hospital-based series of samples including cancer, adenoma and adjacent histologically normal tissue from primary CRC patients (n = 56) and recurrent CRC (n = 16) was studied as well as colon mucosa samples from healthy subjects (n = 76). Furthermore, mtDNA copy number was assessed in carcinomas of 693 CRC cases identified from the population-based Netherlands Cohort Study (NLCS). MtDNA copy number was significantly lower in carcinoma tissue (P = 0.011) and adjacent tissue (P < 0.001) compared to earlier resected adenoma tissue and in primary CRC tissue compared to recurrent CRC tissue (P = 0.011). Within both study populations, mtDNA copy number was significantly lower in mutated BRAF (P = 0.027 and P = 0.006) and in microsatellite unstable (MSI) tumors (P = 0.033 and P < 0.001) and higher in KRAS mutated tumors (P = 0.004). Furthermore, the association between mtDNA and survival seemed to follow an inverse U-shape with the highest HR observed in the second quintile of mtDNA copy number (HR = 1.70, 95% CI = 1.18, 2.44) compared to the first quintile. These results might reflect an association of mtDNA copy number with various malignant processes in cancer cells and warrants further research on tumor energy metabolism in CRC prognosis.

Spectrin Repeat Containing Nuclear Envelope 1 and Forkhead Box Protein E1 Are Promising Markers for the Detection of Colorectal Cancer in Blood

Identifying biomarkers in body fluids may improve the noninvasive detection of colorectal cancer. Previously, we identified N-Myc downstream-regulated gene 4 (NDRG4) and GATA binding protein 5 (GATA5) methylation as promising biomarkers for colorectal cancer in stool DNA. Here, we examined the utility of NDRG4, GATA5, and two additional markers [Forkhead box protein E1 (FOXE1) and spectrin repeat containing nuclear envelope 1 (SYNE1)] promoter methylation as biomarkers in plasma DNA. Quantitative methylation-specific PCR was performed on plasma DNA from 220 patients with colorectal cancer and 684 noncancer controls, divided in a training set and a test set. Receiver operating characteristic analysis was performed to measure the area under the curve of GATA5, NDRG4, SYNE1, and FOXE1 methylation. Functional assays were performed in SYNE1 and FOXE1 stably transfected cell lines. The sensitivity of NDRG4, GATA5, FOXE1, and SYNE1 methylation in all stages of colorectal cancer (154 cases, 444 controls) was 27% [95% confidence interval (CI), 20%–34%), 18% (95% CI, 12%–24%), 46% (95% CI, 38%–54%), and 47% (95% CI, 39%–55%), with a specificity of 95% (95% CI, 93%–97%), 99% (95% CI, 98%–100%), 93% (95% CI, 91%–95%), and 96% (95% CI, 94%–98%), respectively. Combining SYNE1 and FOXE1, increased the sensitivity to 56% (95% CI, 48%–64%), while the specificity decreased to 90% (95% CI, 87%–93%) in the training set and to 58% sensitivity (95% CI, 46%–70%) and 91% specificity (95% CI, 80%–100%) in a test set (66 cases, 240 controls). SYNE1 overexpression showed no major differences in cell proliferation, migration, and invasion compared with controls. Overexpression of FOXE1 significantly decreased the number of colonies in SW480 and HCT116 cell lines. Overall, our data suggest that SYNE1 and FOXE1 are promising markers for colorectal cancer detection. Cancer Prev Res; 8(2); 157–64. ©2014 AACR.

NDRG4, an early detection marker for colorectal cancer, is specifically expressed in enteric neurons

Promoter methylation of N‐myc Downstream‐Regulated Gene 4 (NDRG4) in fecal DNA is an established early detection marker for colorectal cancer (CRC). Despite its connection to CRC, NDRG4 is predominantly studied in brain and heart, with little to no knowledge about its expression or role in other organs. In this study, we aimed to determine the whole‐body expression of NDRG4, with a focus on the intestinal tract.