Erratum: Epigenomic characterization of a p53-regulated 3p22.2 tumor suppressor that inhibits STAT3 phosphorylation via protein docking and is frequently methylated in esophageal and other carcinomas: Erratum.

[This corrects the article DOI: 10.7150/thno.20893.].

The effect on tumour control probability of using AXB algorithm in replacement of AAA for SBRT of hepatocellular carcinoma located at lung-liver boundary region.

OBJECTIVE: To retrospectively analyze the clinical impact on stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) located at lung-liver boundary due to the use of Acuros XB algorithm (AXB) in replacement of anisotropic analytical algorithm (AAA). METHODS: 23 SBRT volumetric modulated arc therapy (VMAT) plans for HCC located at lung-liver boundary were calculated using AAA and AXB respectively with the same treatment parameters. The dose-volume data of the planned target volumes (PTVs) were compared. A published tumour control probability (TCP) model was used to calculate the effect of dosimetric difference between AAA and AXB on tumour control probability. RESULTS: For dose calculated by AXB (Dose to medium), the D95% and D98% of the PTV were on average 2.4 and 3.1% less than that calculated by AAA. For dose calculated by AXB (dose to water), the D95% and D98% of the PTV were on average 1.8%, and 2.7% less than that calculated by AAA. Up to 5% difference in D95% and 8% difference in D98% were observed in the worst cases. The significant decrease in D95% calculated by AXB compared to AAA could result in a % decrease in 2 year TCP up to 8% in the worst case (from 46.8 to 42.9%). CONCLUSION: The difference in dose calculated by AAA and AXB could lead to significant difference in TCP for HCC SBRT located at lung-liver boundary region. ADVANCES IN KNOWLEDGE: The difference in calculated dose and tumour control probability for HCC SBRT between AAA and AXB algorithm at lung-liver boundary region was compared.

Targeting the polycomb repressive complex-2 related proteins with novel combinational strategies for nasopharyngeal carcinoma.

Aberrant epigenetic regulation is critically involved in the pathogenesis of nasopharyngeal carcinoma (NPC), where abnormal histone methylation can be found in polycomb repressive complex-2 (PRC2) related cancer gene loci. This study investigated some novel combinational strategies against NPC in vitro using PRC2-targeting agents as a backbone. PRC2 subunit proteins were overexpressed in over 70% of NPC tumors and enhancer of zeste homolog-2 (EZH2) expression correlated with more advanced T-stage. Basal expression of EZH2 and embryonic ectoderm development (EED) was higher in Epstein-Bar virus (EBV)+ NPC cells than EBV- cells. Treatment with an EED inhibitor (EED226) led to reduced levels of H3K27me3 with minimal inhibitory effect on NPC cell growth. The combination of an EZH2 inhibitor (EPZ-6438) and trichostatin-A (TSA) yielded the highest synergy score (12.64) in NPC cells in vitro than combinations using EED226 and agents like chemotherapy and azacitadine. Global gene expression analysis showed that EED226 predominantly affects the expression of major histocompatibility complex (MHC) class I genes and cell cycle-related genes in NPC cells. Furthermore, treatment with EED226 resulted in increased MHC-I proteins in vitro. Based on the prediction of an artificial neural network, a synergistic inhibitory effect on growth was found by combining EED226 with cyclin dependent kinase (CDK) 4/6 inhibitor (LEE011) in NPC cells. In summary, this study found that PRC2-targeting agents could exert synergistic effect on growth inhibition when combined with TSA or LEE011 in NPC cells. Since MHC-I genes alterations are found in a third of NPC tumors, the effect of EED226 on MHC-I genes expression on response to immunotherapy in NPC warrants further investigations.

Prospective evaluation of plasma Epstein-Barr virus DNA clearance and fluorodeoxyglucose positron emission scan in assessing early response to chemotherapy in patients with advanced or recurrent nasopharyngeal carcinoma.

BACKGROUND: Plasma Epstein-Barr virus (pEBV) DNA and fluorodeoxyglucose positron emission (PET) reflect tumour burden in advanced NPC. This study hypothesised that a dual endpoint based on assessing pEBV DNA clearance and PET response could predict early drug response. METHODS: Eligible patients underwent a computed tomography (CT) scan and dual PET-CT at baseline, a PET-CT at 4 weeks, and then a CT scan at 10 weeks after starting palliative or induction chemotherapy. Plasma EBV DNA clearance was determined. RESULTS: Fifty-eight out of 70 enrolled patients completed all imaging and 50/58 had falling pEBV DNA level, which allowed calculation of the clearance. At a median follow-up of 29.1 months, the dual endpoint (pEBV DNA clearance ≤ 10 days and > 50% drop in sum of SUVmax of target lesions) was an independent indicator of overall survival (hazard ratio (HR) = 0.135, 95% CI = 0.039 to 0.466, p = 0.0015) and progression-free survival (HR = 0.136, 95% CI = 0.048 to 0.385, p = 0002). This dual endpoint could predict subsequent response by Response Evaluation Criteria In Solid Tumours (RECIST) criteria at 10 weeks after chemotherapy. CONCLUSIONS: Early PET-CT response and pEBV DNA clearance could predict survival and subsequent response. This dual endpoint is an innovative tool for assessing early drug response.

Epigenomic characterization of a p53-regulated 3p22.2 tumor suppressor that inhibits STAT3 phosphorylation via protein docking and is frequently methylated in esophageal and other carcinomas.

Rationale: Oncogenic STAT3 signaling activation and 3p22-21.3 locus alteration are common in multiple tumors, especially carcinomas of the nasopharynx, esophagus and lung. Whether these two events are linked remains unclear. Our CpG methylome analysis identified a 3p22.2 gene, DLEC1, as a methylated target in esophageal squamous cell (ESCC), nasopharyngeal (NPC) and lung carcinomas. Thus, we further characterized its epigenetic abnormalities and functions. Methods: CpG methylomes were established by methylated DNA immunoprecipitation. Promoter methylation was analyzed by methylation-specific PCR and bisulfite genomic sequencing. DLEC1 expression and clinical significance were analyzed using TCGA database. DLEC1 functions were analyzed by transfections followed by various cell biology assays. Protein-protein interaction was assessed by docking, Western blot and immunoprecipitation analyses. Results: We defined the DLEC1 promoter within a CpG island and p53-regulated. DLEC1 was frequently downregulated in ESCC, lung and NPC cell lines and primary tumors, but was readily expressed in normal tissues and immortalized normal epithelial cells, with mutations rarely detected. DLEC1 methylation was frequently detected in ESCC tumors and correlated with lymph node metastasis, tumor recurrence and progression, with DLEC1 as the most frequently methylated among the established 3p22.2 tumor suppressors (RASSF1A, PLCD1 and ZMYND10/BLU). DLEC1 inhibits carcinoma cell growth through inducing cell cycle arrest and apoptosis, and also suppresses cell metastasis by reversing epithelial-mesenchymal transition (EMT) and cell stemness. Moreover, DLEC1 represses oncogenic signaling including JAK/STAT3, MAPK/ERK, Wnt/ß-catenin and AKT pathways in multiple carcinoma types. Particularly, DLEC1 inhibits IL-6-induced STAT3 phosphorylation in a dose-dependent manner. DLEC1 contains three YXXQ motifs and forms a protein complex with STAT3 via protein docking, which blocks STAT3-JAK2 interaction and STAT3 phosphorylation. IL-6 stimulation enhances the binding of DLEC1 with STAT3, which diminishes their interaction with JAK2 and further leads to decreased STAT3 phosphorylation. The YXXQ motifs of DLEC1 are crucial for its inhibition of STAT3 phosphorylation, and disruption of these motifs restores STAT3 phosphorylation through abolishing DLEC1 binding to STAT3. Conclusions: Our study demonstrates, for the first time, predominant epigenetic silencing of DLEC1 in ESCC, and a novel mechanistic link of epigenetic DLEC1 disruption with oncogenic STAT3 signaling in multiple carcinomas.

Prognostic values of EORTC QLQ-C30 and QLQ-HCC18 index-scores in patients with hepatocellular carcinoma - clinical application of health-related quality-of-life data.

BACKGROUND: Health-related quality-of-life (HRQOL) assessment with EORTC QLQ-C30 was prognostic for overall survival (OS) in patients with advance-stage hepatocellular carcinoma (HCC), but no data existed for early-stage patients. The HCC-specific QLQ-HCC18 has not been evaluated for prognostic value in HCC patients. Utilization of raw HRQOL data in clinical setting has been impractical and non-meaningful. Therefore we developed index scores of QLQ-C30 and QLQ-HCC18 in an attempt to enable clinical utilization of these HRQOL measurements. This study investigates the prognostic significance of QLQ-C30, QLQ-HCC18 and C30/HCC18 index-scores in patients with newly diagnosed HCC which encompasses all stages. METHODS: From 2007-2011, 517 patients were prospectively recruited. HRQOL was assessed at diagnosis using QLQ-C30 and QLQ-HCC18; C30 and HCC18 index-scores were calculated from raw HRQOL data. Cox regression was performed using continuous, dichotomized QLQ-C30 and QLQ-HCC18 variables, or index-scores, together with clinical factors to identify independent factors for OS. Various multivariate models were validated with c-index and bootstrapping for 1000 replications. RESULTS: Four hundred and seventy two patients had complete HRQOL data. Their median OS was 8.6 months. In multivariate analysis, independent prognostic HRQOL variables for OS were QLQ-C30 pain (HR 1.346 [1.092-1.661], p = 0.0055), QLQ-C30 physical functioning (HR 0.652 [0.495-0.860], p = 0.0024); QLQ-HCC18 pain (HR 1.382 [1.089-1.754], p = 0.0077) and QLQ-HCC18 fatigue (HR 1.441 [1.132-1.833], p = 0.0030). C30 index-score (HR 2.143 [1.616-2.841], p < 0.0001) and HCC18 index-score (HR 1.957 [1.411-2.715], p < 0.0001) were highly significant factors for OS. The median OS of patients with C30 index-score of 0-20, 21-40, 41-60, 61-100 were 16.4, 7.3, 3.1, 1.8 months respectively (p < 0.0001); while for HCC18 index-score: 16.4, 6.0, 2.8, 1.8 months respectively (p < 0.0001). All the multivariate models were validated, with mean optimism <0.01. The bootstrap validated c-index was 0.78. CONCLUSIONS: QLQ-C30 and QLQ-HCC18 were prognostic for OS in patients with newly diagnosed HCC irrespective of stage. Both C30 and HCC18 index-scores were highly significant prognostic factors for OS in newly diagnosed HCC patients. Index-scoring provides an effective way to summarize, analyze and interpret raw HRQOL data, and renders QLQ-C30 and QLQ-HCC18 meaningful and communicable in clinical practice. Index-scores could potentially serve as a standardized tool for future HRQOL research.

Epigenetic inactivation of the CpG demethylase TET1 as a DNA methylation feedback loop in human cancers.

Promoter CpG methylation is a fundamental regulatory process of gene expression. TET proteins are active CpG demethylases converting 5-methylcytosine to 5-hydroxymethylcytosine, with loss of 5 hmC as an epigenetic hallmark of cancers, indicating critical roles of TET proteins in epigenetic tumorigenesis. Through analysis of tumor methylomes, we discovered TET1 as a methylated target, and further confirmed its frequent downregulation/methylation in cell lines and primary tumors of multiple carcinomas and lymphomas, including nasopharyngeal, esophageal, gastric, colorectal, renal, breast and cervical carcinomas, as well as non-Hodgkin, Hodgkin and nasal natural killer/T-cell lymphomas, although all three TET family genes are ubiquitously expressed in normal tissues. Ectopic expression of TET1 catalytic domain suppressed colony formation and induced apoptosis of tumor cells of multiple tissue types, supporting its role as a broad bona fide tumor suppressor. Furthermore, TET1 catalytic domain possessed demethylase activity in cancer cells, being able to inhibit the CpG methylation of tumor suppressor gene (TSG) promoters and reactivate their expression, such as SLIT2, ZNF382 and HOXA9. As only infrequent mutations of TET1 have been reported, compared to TET2, epigenetic silencing therefore appears to be the dominant mechanism for TET1 inactivation in cancers, which also forms a feedback loop of CpG methylation during tumorigenesis.

Silencing of hypoxia-inducible tumor suppressor lysyl oxidase gene by promoter methylation activates carbonic anhydrase IX in nasopharyngeal carcinoma.

Lysyl oxidase (LOX) is an oxidative enzyme known to initiate the cross-linking of collagens and elastin, and suggested recently as a tumor suppressor for several tumor types including lung, pancreatic and gastric cancers. Previously we showed that LOX is strongly induced upon hypoxia in nasopharyngeal carcinoma (NPC) cell lines CNE2 and HONE1 but only slightly in HK1 and not in C666-1. Here, we further studied the regulatory mechanism and functions of LOX in NPC. LOX is widely expressed in human normal tissues with variations in expression levels. LOX was expressed in most NPC cell lines except for C666-1, while HK1 and FaDu (laryngeal cancer) only expressed low level of LOX. Methylation analysis showed that the LOX promoter was methylated in C666-1 and partially methylated in HK1. After demethylation with 5-aza-2'-deoxycytidine, LOX expression was reactivated along with increased unmethylated alleles. LOX promoter methylation was detected in 42/49 (85.7%) of NPC primary tumors but only 3/16 (18.75%) of nose swab samples from NPC patients. LOX overexpression reduced the clonogenicity and cell growth of NPC cells, and also inhibited the migration and invasion of the NPC cells. Carbonic anhydrase IX (CA9) mRNA level was obviously decreased in HK1 cells after transfection with LOX. The elevation of CA9 protein upon hypoxia was inhibited in LOX-transfected HK1 cells. The protein levels of an apoptosis marker cPARP were increased in LOX-transfected HK1 cells upon hypoxia treatment. Our data showed that silencing or down-regulation of LOX in NPC was due to its promoter methylation and LOX acts as a tumor suppressor in NPC. LOX silencing would facilitate NPC cells to escape from hypoxia-induced apoptosis and maintains a malignant and metastatic phenotype.

Addition of bevacizumab to standard chemoradiation for locoregionally advanced nasopharyngeal carcinoma (RTOG 0615): a phase 2 multi-institutional trial.

BACKGROUND: We aimed to improve the outcomes for locoregionally advanced nasopharyngeal carcinoma by testing the feasibility and safety of the addition of bevacizumab to chemoradiotherapy. METHODS: We enrolled patients older than 18 years with stage IIB-IVB nasopharyngeal carcinoma from 19 centres in North America and Hong Kong. Treatment consisted of three cycles of bevacizumab (15 mg/kg) and cisplatin (100 mg/m(2)) both given on days 1, 22, and 43 of radiation (70 Gy) with intensity-modulated radiation therapy delivered over 33 days on a daily basis, Monday through Friday. Patients then received three cycles of bevacizumab (15 mg/kg) and cisplatin (80 mg/m(2)), both given on days 64, 85, and 106 after radiation, and three cycles of fluorouracil (1000 mg/m(2) per day), given on days 64-67, 85-88, and 106-109 after radiation. The primary endpoint was the occurrence of treatment-related grade 4 haemorrhage or any grade 5 adverse event in the first year. Analyses were done with all eligible patients who started protocol treatment. The trial is registered at ClinicalTrials.gov, number NCT00408694. FINDINGS: From Dec 13, 2006, to Feb 5, 2009, we enrolled 46 patients, of whom 44 were eligible for analysis. We recorded no grade 3-4 haemorrhages or grade 5 adverse events; nine patients (20%) had a treatment-related grade 1-2 haemorrhage. Nine patients had one or more grade 4 blood or bone marrow-related complication (grade 4 leucopenia was noted in six patients, grade 4 lymphopenia in five, grade 4 neutrophils in five, and grade 4 anaemia in one). One patient had two grade 4 infections with grade 3-4 neutrophils. One patient reported grade 4 tinnitus, one patient reported grade 4 thrombosis, one reported grade 4 radiation mucositis, and two reported grade 4 pharyngolaryngeal pain. With a median follow-up of 2·5 years (IQR 2·1-2·9), the estimated 2 year locoregional progression-free interval was 83·7% (95% CI 72·6-94·9), the 2 year distant metastasis-free interval was 90·8% (82·2-99·5), the 2 year progression-free survival was 74·7% (61·8-87·6), and 2 year overall survival was 90·9% (82·3-99·4). INTERPRETATION: The addition of bevacizumab to standard chemoradiation treatment for patients with nasopharyngeal carcinoma is feasible, and might delay the progression of subclinical distant disease. FUNDING: National Cancer Institute, USA.

Anti-invasion, anti-proliferation and anoikis-sensitization activities of lapatinib in nasopharyngeal carcinoma cells.

Nasopharyngeal cancer (NPC) is a highly prevalent and invasive head and neck cancer in Asia. Disease recurrence and distant metastasis account for major NPC deaths. Therefore, more effective therapy is needed. Lapatinib, a dual tyrosine kinase inhibitor (TKI) against both EGFR and HER-2, has been known to exert potent antitumor activity against several cancer models. Given that both EGFR and HER-2 are co-expressed in NPC, we hypothesized that dual targeting of EGFR and HER-2 by this small molecule EGFR/HER-2 TKI would elicit anti-tumor activity in NPC. Using in vitro models of NPC, we demonstrated that lapatinib was able to efficiently inhibit the phosphorylation of both EGFR and HER-2. This was accompanied by significant growth inhibition of NPC cells (with maximal growth inhibition >90%). For the most lapatinib-sensitive cell line (HK1-LMP1, with IC(50) ∼ 600 nM), which harbored the highest levels of both EGFR and HER-2, inhibition of cell growth was associated G(0)/G(1) cell cycle arrest, marked PARP cleavage, caspase-3 cleavage, as well as significant downregulation of several important survival proteins (e.g. survivin, Mcl-1 and cyclin D1). NPC cells are intrinsically invasive. We found that lapatinib was able to inhibit cellular invasion of both HK1-LMP1 and HONE-1 cells. Furthermore, our data demonstrated for the first time that lapatinib harbored potent anoikis-sensitization activity (i.e. sensitizing cancer cells to detachment-induced apoptosis) in human cancer cells overexpressing both EGFR and HER-2 (HK1-LMP1 and HK1). Taken together, our findings suggest that lapatinib is a promising anti-cancer agent for NPC with anti-invasion and anoikis-sensitization activities.

TOP2A overexpression in hepatocellular carcinoma correlates with early age onset, shorter patients survival and chemoresistance.

Genomic gain represents an important mechanism in the activation of proto-oncogenes. In many instances, induced oncogenes hold clinical implications both as prognostic markers and targets for therapeutic design. In hepatocellular carcinoma (HCC), although chromosomal gains are common, information on underlying oncogenes induced remains minimal. Here, we examined 7 causal sites of HCC for overexpressed genes by array-based transcriptional mapping. In 22 HCC cell lines and early passages of cultures studied, clusters of up-regulated genes were indicated, where TOP2A expression ranked the highest. Distinct TOP2A transcriptions were confirmed in an independent series of HCC tumors relative to adjacent non-tumoral liver (p=0.0018). By tissue microarray analysis of 172 HCC, we found TOP2A expressions correlated with advance histological grading (p<0.001), microvascular invasion (p=0.004) and an early age onset of the malignancy (