SULF2 methylation is prognostic for lung cancer survival and increases sensitivity to topoisomerase-I inhibitors via induction of ISG15

Abstract

The heparan sulfate 6-O-endosulfatase (SULF2) promotes growth and metastasis of solid tumors. We recently identified that cytosine methylation of the SULF2 promoter is associated with better survival of resected lung adenocarcinoma patients and now also demonstrate a marginal improvement in survival of advanced non-small cell lung cancer (NSCLC) patients receiving standard chemotherapy (HR = 0.63, p = 0.07). Subsequent studies focused on investigating the effect of methylation on SULF2 expression and its genome-wide impact. The genes and pathways modulated by epigenetic inactivation of SULF2 and the effects on sensitivity to chemotherapy were characterized in vitro and in vivo. Silencing SULF2 through siRNA or methylation primarily increased expression of interferon-inducible genes including ISG15, a marker for increased sensitivity to topoisomerase-1 inhibitors such as camptothecin. NSCLC cell lines with methylated SULF2 (SULF2M) express 60-fold higher ISG15 compared to SULF2 unmethylated (SULF2U) NSCLC cell lines and normal human bronchial epithelial cells. In vitro, SULF2M and high ISG15 (ISG15H) expressing NSCLC cell lines were 134-fold more sensitive to camptothecin than SULF2U and low ISG15 (ISG15L) expressing cell lines. Topotecan, a soluble analogue of camptothecin and FDA approved anti-cancer drug, dramatically arrested the growth of SULF2M-ISG15H, but not SULF2U-ISG15L lung tumors in nude mice (p < 0.002). Similarly, high ISG15 expression that is comparable to the topotecan sensitive NSCLC cell lines was found in tumors from 25% of NSCLC patients compared to normal lung indicating a potential to identify and target the most sensitive NSCLC subpopulation for personalized topotecan therapy.

Comparison of different normalization assumptions for analyses of DNA methylation data from the cancer genome

“…For another example, SULF2, an endosulfatase able to cleave specific 6-O sulfate groups within the heparan chains, was additionally identified to be hypomethylated in the Quantile-normalized data for colorectal, kidney and stomach cancer. It was found that SULF2 was over-expressed in various human cancer types and associated to cancer progression and prognosis (Bret et al, 2011;Lemjabbar-Alaoui et al, 2010;Tessema et al, 2011). These important cancer related genes identified by Quantile normalization suggested the effectiveness of this normalization algorithm on identifying DM genes.…”

Long noncoding RNA-HOTAIR affects chemoresistance by regulating HOXA1 methylation in small cell lung cancer cells

“…9 In NSCLC, SULF2 and IGFBP-3 have also been observed to affect drug sensitivity of NSCLC cells. [10][11][12] The HOX family, including 39 HOX genes, is divided into four groups (A-D) in tightly linked clusters on different chromosomes, and has the equivalent position in each cluster. HOXA1, one of the HOX family members, has been reported to be involved in many important biological processes including cell growth, apoptosis, transformation, and survival.…”

Epigenetic Repression of CCDC37 and MAP1B Links Chronic Obstructive Pulmonary Disease to Lung Cancer

“…Expression of CCDC37 , MAP1B, and BETA-ACTIN was quantified using Hs00403623_m1, Hs00195485_m1, and 4310881E TaqMan assays (Applied Biosystems), respectively, as described. 24,25 All samples were analyzed at least twice in duplicate and expression levels were calculated using ΔΔCT method. 26 …”