Clinical Significance of IGFBP-3 Methylation in Patients with Early Stage Gastric Cancer

Clinicopathological correlation of insulin-like growth factor binding protein 3 and their death receptor in patients with gastric cancer

Background and purpose

The insulin-like growth factor binding protein 3 (IGFBP-3) and its novel death receptor (IGFBP-3R) have been exhibited to have tumor suppressor effects. Despite their prognostic value in some cancers, they have not been elucidated in gastric cancer.

Experimental approach

We collected 68 samples from patients with gastric cancer. IGFBP-3 and IGFBP-3R expression levels were evaluated with quantitative real-time polymerase chain reaction (RT-PCR) and western blotting in patients. The relationship between prognostic factors and IGFBP-3/IGFBP-3R expression was also evaluated.

Findings/Results

Our results showed that IGFBP-3 and IGFBP-3R expression was reduced significantly in tumor tissues. We found that there was an association between the reduction of IGFBP-3 with lymph node metastasis and tumor-node-metastasis (TNM) staging. Besides, IGFBP-3R expression was associated with tumor size, lymph node metastasis, differentiation, and TNM classification. Interestingly, we presented that the downregulation of IGFBP-3R was stage-dependent. In survival analysis, our findings showed that low levels of IGFBP-3R mRNA expression exhibited a close correlation with survival rate.

Conclusion and implications

The findings of this study showed that the expression levels of IGFBP-3 and IGFBP-3R are valuable prognostic factors. Despite the potential of IGFBP-3, IGFBP-3R plays a significant role as a prognostic factor in gastric cancer. However, these findings need to be developed and confirmed by further studies.

The Interplay Between Non-coding RNAs and Insulin-Like Growth Factor Signaling in the Pathogenesis of Neoplasia

The insulin-like growth factors (IGFs) are polypeptides with similar sequences with insulin. These factors regulate cell growth, development, maturation, and aging via different processes including the interplay with MAPK, Akt, and PI3K. IGF signaling participates in the pathogenesis of neoplasia, insulin resistance, diabetes mellitus, polycystic ovarian syndrome, cerebral ischemic injury, fatty liver disease, and several other conditions. Recent investigations have demonstrated the interplay between non-coding RNAs and IGF signaling. This interplay has fundamental roles in the development of the mentioned disorders. We designed the current study to search the available data about the role of IGF-associated non-coding RNAs in the evolution of neoplasia and other conditions. As novel therapeutic strategies have been designed for modification of IGF signaling, identification of the impact of non-coding RNAs in this pathway is necessary for the prediction of response to these modalities.

IGFBP3 gene promoter methylation analysis and its association with clinicopathological characteristics of colorectal carcinoma

Promoter methylation mediated silencing of tumor suppressor genes plays an important role in the tumorigenesis of colorectal carcinoma (CRC). Tumor suppressor gene, Insulin-like Growth Factor Binding Protein-3 (IGFBP-3) expression is frequently downregulated in CRC due to promoter methylations. The aim of this study was to analyze the methylation status of IGFBP-3 gene promoter in stage II and III of CRC cases; find its association with clinicopathological characteristics of CRC patients and the methylation patterns as a prognostic biomarker. 58 histopathologically confirmed cases of CRC were included in the study. Methylation status of IGFBP-3 gene promoter was determined by using methylation specific PCR (MS-PCR) and bisulfite sequencing. Kaplan-Meier survival curve and univariate cox regression analysis were used for survival analysis; Chi-square test used for association analysis. IGFBP3 promoter methylation was found in 37 (63.8%) out of 58 CRC cases. This promoter methylation status was significantly associated with lymph-node metastasis (P = 0.013) and the survival period. In stage II CRC cases, unmethylated gene promoter status showed better survival than the methylated. Mean overall survival (OS) of methylated and unmethylated group was 22.23 months, and 49.15 months respectively (P = 0.045), HR = 6.432, 95% CI 0.986-41.943. The IGFBP-3 promoter methylations found in 63.8% CRC cases in this study. The methylations was found to be associated with lymph-node metastasis and overall survival of the patients particularly in stage II CRC patients. However, promoter methylation was not associated with other clinocopathological characteristics such as age, gender, tumor location etc.

DNA methyltransferases and gastric cancer: insight into targeted therapy

Gastric cancer is a major health problem worldwide occupying most frequent causes of cancer-related mortality. In addition to genetic modifications, epigenetic alterations catalyzed by DNA methyltransferases (DNMTs) are a well-characterized epigenetic hallmark in gastric cancer. The reversible nature of epigenetic alterations and central role of DNA methylation in diverse biological processes provides an opportunity for using DNMT inhibitors to enhance the efficacy of chemotherapeutics. In this review, we discussed key factors or mechanisms such as SNPs, infections and genetic modifications that trigger DNMTs level modification in gastric cancer, and their potential roles in cancer progression. Finally, we focused on how inhibitors of the DNMTs can most effectively be used for the treatment of gastric cancer with multidrug resistance.

In silico interaction of insulin-like growth factor binding protein 3 with insulin-like growth factor 1

Insulin-like growth factor binding protein-3 (IGFBP-3) is a vital protein exist in circulation which interacts with high affinity to insulin-like growth factor (IGFs) altering their activities. Therefore, the interaction between IGFs and IGFBP-3 has a key role altering large spectrum of activities such as cell cycle progression, proliferation and apoptosis. Despite decades of research, the crystal structure of IGFBP-3 has not been identified possibly due to some technical challenge in its crystallizing. The three-dimensional (3D) structure of IGFBP-3 was predicted using homology modeling, Phyre2, and molecular dynamic. Its interaction with IGF-1 was also identified by HADDOCK software. IGFBP-3 has the most identity with other IGFBPs in N and C-domain; however, its linker domain has lower identity. Our data predicted that IGF-1 structurally interacts with N-domain and linker domain of IGFBP-3. Some conserved residues of IGFBP-3 such as Glu33, Arg36, Gly39, Arg60, Arg66, Asn109, and Ile146 interacts with Glu3, Asp12, Phe16, Gly19, Asp20, Arg21, and Glu58 of IGF-1. In addition, our data predict that the linker domain has a loop structure which covers post translational modification and interacts with IGF-1. The phosphorylation of Ser111 in linker domain, which previously has been shown to induce apoptosis make a repulsive force interrupting this interaction to IGF-1, which enables IGFBP-3 to induce apoptosis. The present study suggests that the linker domain has a key role in recognition of IGFBP-3 with IGF-1.

The value of serum RASSF10 hypermethylation as a diagnostic and prognostic tool for gastric cancer

The tumor-suppressing role of Ras-association domain family 10 (RASSF10) has been described in several types of cancers. Here, we evaluated the potential use of the hypermethylation status of the RASSF10 promoter in serum as a new diagnostic and prognostic tool in gastric cancer (GC). We used bisulfite sequencing polymerase chain reaction to examine RASSF10 methylation levels in serum and/or tumor samples from 82 GC, 45 chronic atrophic gastritis (CAG), and 50 healthy control patients. In the serum of GC patients, the median level of RASSF10 methylation was higher at 47.84 % than those in the serum of CAG and healthy control patients at 11.89 and 11.35 %, respectively. The median level of RASSF10 methylation in GC tumor tissue was similarly high at 62.70 %. Furthermore, RASSF10 methylation levels were highly correlated between paired serum and tumor samples from GC patients. We performed receiver-operating characteristic curve analyses to verify that serum RASSF10 methylation levels could effectively distinguish GC from control patients. Moreover, multivariate analyses showed that high serum RASSF10 methylation levels in GC patients were associated with large tumors, lymph node metastasis, and high carcinoembryonic antigen (CEA) levels. Survival analyses showed that GC patients with high serum RASSF10 methylation levels had shorter overall and disease-free survival after D2 lymphadenectomy than those with low levels. High serum RASSF10 methylation levels were also an independent predictor of tumor recurrence and GC patient survival. In conclusion, serum RASSF10 promoter methylation levels can serve as a valuable indicator for the diagnosis and prognosis of GC in the clinic.

Potential Biomarkers in Diagnosis of Human Gastric Cancer

The high incidence of gastric cancer (GC) and its consequent mortality rate severely threaten human's health. It is not frequently diagnosed until a relatively advanced stage. Surgery is the only potentially curative treatment. Thus, early screening and diagnosis are critical for patients with GC. The tumor marker assays used currently for detecting GC are simple and rapid, but the usage is limited by its low sensitivity and specificity. Here, we provide a brief description of some new potential markers and new biotechnological methods for the diagnosis of GC, hoping to find out more effective approaches for early detection of GC.