LINE-1 hypomethylation in gastric cancer, detected by bisulfite pyrosequencing, is associated with poor prognosis

BACKGROUND: Genome-wide DNA hypomethylation plays an important role in genomic instability and carcinogenesis. DNA methylation in the long interspersed nucleotide element-1, L1 (LINE-1) repetitive element is a good indicator of the global DNA methylation level. In some types of human neoplasms, LINE-1 methylation level is attracting interest as a predictive marker for patient prognosis. However, the prognostic significance of LINE-1 hypomethylation in gastric cancer remains unclear. METHODS: Using 203 resected gastric cancer specimens, we quantified LINE-1 methylation using bisulfite-pyrosequencing technology. A Cox proportional hazards model was used to calculate the hazard ratio (HR), adjusted for the clinical and pathological variables. RESULTS: Gastric cancers showed significantly lower LINE-1 methylation levels compared to matched normal gastric mucosa (p < 0.0001; n = 74). Tumoral LINE-1 methylation range was 11.6–97.5 on a 0–100 scale (n = 203; mean 71.4, median 74.4, standard deviation 12.9). LINE-1 hypomethylation was significantly associated with shorter overall survival [log-rank p = 0.029; univariate HR 2.01, 95 % confidence interval (CI) 1.09–3.99, p = 0.023; stage-matched HR 1.88, 95 % CI 1.02–3.74, p = 0.041; multivariate HR 1.98, 95 % CI 1.04–4.04, p = 0.036]. No significant effect modification was observed by any of the covariates in survival analysis (all p interaction >0.25). CONCLUSIONS: LINE-1 hypomethylation in gastric cancer is associated with shorter survival, suggesting that it has potential for use as a prognostic biomarker

Anti-Tumor Effect against Human Cancer Xenografts by a Fully Human Monoclonal Antibody to a Variant 8-Epitope of CD44R1 Expressed on Cancer Stem Cells

BACKGROUND: CD44 is a major cellular receptor for hyaluronic acids. The stem structure of CD44 encoded by ten normal exons can be enlarged by ten variant exons (v1-v10) by alternative splicing. We have succeeded in preparing MV5 fully human IgM and its class-switched GV5 IgG monoclonal antibody (mAb) recognizing the extracellular domain of a CD44R1 isoform that contains the inserted region coded by variant (v8, v9 and v10) exons and is expressed on the surface of various human epithelial cancer cells. METHODS AND PRINCIPAL FINDINGS: We demonstrated the growth inhibition of human cancer xenografts by a GV5 IgG mAb reshaped from an MV5 IgM. The epitope recognized by MV5 and GV5 was identified to a v8-coding region by the analysis of mAb binding to various recombinant CD44 proteins by enzyme-linked immunosorbent assay. GV5 showed preferential reactivity against various malignant human cells versus normal human cells assessed by flow cytometry and immunohistological analysis. When ME180 human uterine cervix carcinoma cells were subcutaneously inoculated to athymic mice with GV5, significant inhibition of tumor formation was observed. Furthermore, intraperitoneal injections of GV5markedly inhibited the growth of visible established tumors from HSC-3 human larynx carcinoma cells that had been subcutaneously transplanted one week before the first treatment with GV5. From in vitro experiments, antibody-dependent cellular cytotoxicity and internalization of CD44R1 seemed to be possible mechanisms for in vivo anti-tumor activity by GV5. CONCLUSIONS: CD44R1 is an excellent molecular target for mAb therapy of cancer, possibly superior to molecules targeted by existing therapeutic mAb, such as Trastuzumab and Cetuximab recognizing human epidermal growth factor receptor family

Conflicting metabolic alterations in cancer stem cells and regulation by the stromal niche

Recent studies have revealed that cancer stem cells (CSCs) undergo metabolic alterations that differentiate them from non-CSCs. Inhibition of specific metabolic pathways in CSCs has been conducted to eliminate the CSC population in many types of cancer. However, there is conflicting evidence about whether CSCs depend on glycolysis or mitochondrial oxidative phosphorylation (OXPHOS) to maintain their stem cell properties. This review summarizes the latest knowledge regarding CSC-specific metabolic alterations and offers recent evidence that the surrounding microenvironments may play an important role in the maintenance of CSC properties

Prognostic Nutritional Index Predicts Outcomes of Gastrectomy in the Elderly

Background Owing to the increased life expectancy, elderly patients with gastric cancer is also increasing. Onodera\u27s prognostic nutritional index (PNI) is an assessment tool for nutritional status of surgical patients and possibly predicts prognosis of the patients. The aim of the present study is to clarify the predictive and prognostic significance of PNI in elderly patients who underwent gastrectomy for gastric cancer. Methods Two hundred ninety-five patients, including 196 nonelderly patients under 75 years old (group NE) and 99 elderly patients (group E), were eligible. We collected the data on nutritional status and the outcome of gastrectomy, including morbidity, mortality, and survival of these patients. A Cox proportional hazards model was used to evaluate the prognostic significance. Results The PNI was significantly lower in group E than in group NE. Both morbidity and mortality rates after gastrectomy were similar between the groups. Although PNI could not predict the postoperative events in group NE, low PNI might be a risk of mortality and morbidity in the elderly. Although survival after gastrectomy was similar among groups divided by the median PNI value (49.2) in group NE, the prognosis of PNI-L (<44.7) was significantly poorer than PNI-H (PNI≥44.7) in group E. Multivariate analysis demonstrated that PNI-L was an independent prognostic factor in the elderly. Conclusions The PNI predicts both short-term and longterm outcomes after gastrectomy in the elderly

Protocol to establish cancer-associated fibroblasts from surgically resected tissues and generate senescent fibroblasts

Summary: Accumulating evidence suggests that the malignant behavior of cancer is influenced by stromal activity in the tumor microenvironment. Cancer-associated fibroblasts (CAFs), which are the main component of the cancerous stroma, play an important role in cancer development. Here, we describe a protocol to establish CAFs from surgically resected tissues. CAFs could be a vital tool for understanding the microenvironment and its impact on tumor progression and metastasis. Moreover, we generated inflammation-induced senescent fibroblasts that more closely mimic the tumor microenvironment.For complete details on the use and execution of this protocol, please refer to Yasuda et al. (2021)

Noncoding RNA Expression Aberration Is Associated with Cancer Progression and Is a Potential Biomarker in Esophageal Squamous Cell Carcinoma

Esophageal cancer is one of the most common cancers worldwide. Esophageal squamous cell carcinoma (ESCC) is the major histological type of esophageal cancer in Eastern Asian countries. Several types of noncoding RNAs (ncRNAs) function as key epigenetic regulators of gene expression and are implicated in various physiological processes. Unambiguous evidence indicates that dysregulation of ncRNAs is deeply implicated in carcinogenesis, cancer progression and metastases of various cancers, including ESCC. The current review summarizes recent findings on the ncRNA-mediated mechanisms underlying the characteristic behaviors of ESCC that will help support the development of biomarkers and the design of novel therapeutic strategies