Role of SPARC in the epithelial-mesenchymal transition induced by PTHrP in human colon cancer cells.

Parathyroid hormone-related peptide (PTHrP) exerts its effects on cells derived from colorectal cancer (CRC) and tumor microenvironment and is involved in processes requiring the epithelial-mesenchymal transition (EMT). Here, we report that PTHrP modulates factors expression and morphological changes associated with EMT in HCT116 cells from CRC. PTHrP increased the protein expression of SPARC, a factor involved in EMT, in HCT116 cells but not in Caco-2 cells also from CRC but with less aggressiveness. PTHrP also increased SPARC expression and its subsequent release from endothelial HMEC-1 cells. The conditioned media of PTHrP-treated HMEC-1 cells induced early changes related to EMT in HCT116 cells. Moreover, SPARC treatment on HCT116 cells potentiated PTHrP modulation in E-cadherin expression and cell migration. In vivo PTHrP also increased SPARC expression and decreased E-cadherin expression. These results suggest a novel PTHrP action on CRC progression involving the microenvironment in the modulation of events associated with EMT.

IGFBP-3 Gene Methylation in Primary Tumor Predicts Recurrence of Stage II Colorectal Cancers.

OBJECTIVES: To evaluate the influence of IGFBP-3 methylation on recurrence in patients with stage II colorectal cancer (CRC) from 2 independent cohorts. BACKGROUND: The relationship between IGFBP-3 methylation in primary tumors (PTs) or lymph nodes (LNs) and risk of recurrence in patients with stage II CRC treated with surgery alone is unknown. METHODS: IGFBP-3 methylation of DNA from 115 PTs and 1641 LNs in patients with stage II CRC from 2 independent cohorts was analyzed. Forty patients developed recurrence, whereas 75 matched patients remained recurrence free for more than 2 years after surgery. Cox proportional hazard models were used to calculate hazard ratios (HRs) of recurrence, adjusted for patient and tumor characteristics. RESULTS: Methylation of IGFBP-3 in PTs was identified to be significantly associated with risk of recurrence in the training set. The signature was tested in a validation set and classified 40.7% of patients as high risk. Five-year recurrence-free survival rates were 76.4% and 58.3% for low- and high-risk patients, respectively, with an HR of 2.21 (95% confidence interval, 1.04-4.68; P = 0.039). In multivariate analysis, the signature remained the most significant prognostic factor, with an HR of 2.40 (95% confidence interval, 1.10-5.25; P = 0.029). A combined analysis of 1641 LNs from the 2 sets identified IGFBP-3 methylation in LNs was not associated with risk of recurrence. CONCLUSIONS: Detection of IGFBP-3 methylation in PTs, but not in LNs, provides a powerful tool for the identification of patients with stage II CRC at high risk of recurrence.

Epigenetic silencing of neurofilament genes promotes an aggressive phenotype in breast cancer.

Neurofilament heavy polypeptide (NEFH) has recently been identified as a candidate DNA hypermethylated gene within the functional breast cancer hypermethylome. NEFH exists in a complex with neurofilament medium polypeptide (NEFM) and neurofilament light polypeptide (NEFL) to form neurofilaments, which are structural components of the cytoskeleton in mature neurons. Recent studies reported the deregulation of these proteins in several malignancies, suggesting that neurofilaments may have a role in other cell types as well. Using a comprehensive approach, we studied the epigenetic inactivation of neurofilament genes in breast cancer and the functional significance of this event. We report that DNA methylation-associated silencing of NEFH, NEFL, and NEFM in breast cancer is frequent, cancer-specific, and correlates with clinical features of disease progression. DNA methylation-mediated inactivation of these genes occurs also in multiple other cancer histologies including pancreas, gastric, and colon. Restoration of NEFH function, the major subunit of the neurofilament complex, reduces proliferation and growth of breast cancer cells and arrests them in Go/G1 phase of the cell cycle along with a reduction in migration and invasion. These findings suggest that DNA methylation-mediated silencing of the neurofilament genes NEFH, NEFM, and NEFL are frequent events that may contribute to the progression of breast cancer and possibly other malignancies.

Novel methylation biomarker panel for the early detection of pancreatic cancer.

PURPOSE: Pancreatic cancer is the fourth leading cause of cancer deaths and there currently is no reliable modality for the early detection of this disease. Here, we identify cancer-specific promoter DNA methylation of BNC1 and ADAMTS1 as a promising biomarker detection strategy meriting investigation in pancreatic cancer. EXPERIMENTAL DESIGN: We used a genome-wide pharmacologic transcriptome approach to identify novel cancer-specific DNA methylation alterations in pancreatic cancer cell lines. Of eight promising genes, we focused our studies on BNC1 and ADAMTS1 for further downstream analysis, including methylation and expression. We used a nanoparticle-enabled methylation on beads (MOB) technology to detect early-stage pancreatic cancers by analyzing DNA methylation in patient serum. RESULTS: We identified two novel genes, BNC1 (92%) and ADAMTS1 (68%), that showed a high frequency of methylation in pancreatic cancers (n = 143), up to 100% in PanIN-3 and 97% in stage I invasive cancers. Using the nanoparticle-enabled MOB technology, these alterations could be detected in serum samples (n = 42) from patients with pancreatic cancer, with a sensitivity for BNC1 of 79% [95% confidence interval (CI), 66%-91%] and for ADAMTS1 of 48% (95% CI, 33%-63%), whereas specificity was 89% for BNC1 (95% CI, 76%-100%) and 92% for ADAMTS1 (95% CI, 82%-100%). Overall sensitivity using both markers is 81% (95% CI, 69%-93%) and specificity is 85% (95% CI, 71%-99%). CONCLUSIONS: Promoter DNA methylation of BNC1 and ADAMTS1 is a potential biomarker to detect early-stage pancreatic cancers. Assaying the promoter methylation status of these genes in circulating DNA from serum is a promising strategy for early detection of pancreatic cancer and has the potential to improve mortality from this disease.