- Open Access
Decreased miR-198 expression and its prognostic significance in human gastric cancer
© Cui et al. 2016
Received: 5 September 2015
Accepted: 27 January 2016
Published: 6 February 2016
MicroRNAs (miRNAs) have been proved to play important roles in the tumorigenesis and development of human gastric cancer (GC). Our study aims to investigate the expression and clinical significance of miR-198 in GC patients.
Quantitative real-time polymerase chain reaction (RT-PCR) was performed to evaluate miR-198 levels in 106 pairs of GC specimens and adjacent noncancerous tissues. Then, the associations of miR-198 expression with clinicopathological factors and patient’s survival were determined.
The expression levels of miR-198 in GC tissues were significantly lower than those in corresponding noncancerous tissues (p < 0.01). Decreased miR-198 expression was significantly associated with larger tumor size, deeper invasion depth, positive lymph node metastasis, advanced tumor-node-metastasis (TNM) stage, and shorter overall survival. Moreover, multivariate regression analysis identified low miR-198 expression as an independent predictor of poor survival.
These findings suggested that miR-198 downregulation may be associated with progression of GC and that this miR may be an independent prognostic marker for GC patients.
Gastric cancer (GC) is the fourth most prevalent human malignancy and the second leading cause of cancer death worldwide . The majority of GC patients are diagnosed at advanced stage due to vague initial symptoms . Despite recent advances in surgical techniques, new chemotherapy regimens, radiotherapy, and molecular targeted therapy, the clinical outcome of patients with GC remains dismal, with a 5-year survival rate of 25 % or less . Previous studies have reported many oncogenes and tumor suppressor genes closely associated with GC [4–6], but the highly complex molecular mechanisms underlying its carcinogenesis and progression are still obscure. Therefore, it is urgent to identify reliable biomarkers of GC for its early diagnosis, effective therapy, and prognosis evaluation.
MicroRNAs (miRNAs) are a class of naturally occurring, short (about 22 nucleotides in length), single-stranded, non-protein-coding RNAs that negatively regulate gene expression . It is estimated that about 60 % genes can be regulated by miRNAs . They suppress translation or promote the degradation of target messenger RNAs (mRNAs) through base pairing with the 3ʹ-untranslated regions (3ʹ-UTRs) [7, 9]. Previous research has shown that miRNAs have critical roles in various biological processes, such as development, differentiation, cell growth, inflammation, stress response, and endocrine homeostasis . Emerging evidence demonstrates that aberrant miR expression is highly associated with cancer initiation and progression, which may provide a new but promising way to deal with cancer [11–13]. miRNAs can function as either oncogenes or tumor suppressors according to the roles of their target genes. Deregulation or dysfunction of miRNAs is involved in many processes of tumor progression including cell proliferation, apoptosis, invasion, metastasis, angiogenesis, and epithelial-to-mesenchymal transition [14–16]. Functional miRNAs may be applied for cancer diagnosis and prognosis and also act as potential novel therapeutic targets.
miR-198 is a recently identified cancer-related miR. It is observed to be downregulated in lung cancer , colorectal cancer , hepatocellular carcinoma , pancreatic cancer , ovarian cancer , and prostate cancer , and acts as a potential tumor suppressor in these tumors. Yet miR-198 was reported to be upregulated in retinoblastoma and squamous cell carcinoma of the tongue [23, 24], indicating that miR-198 may not behave as a tumor suppressor in all cases. However, the expression and clinical significance of miR-198 in GC is still unclear. In the present study, we examined miR-198 expression in GC tissues and paired adjacent noncancerous tissues. The relationship between miR-198 expression and clinicopathological features and patient’s survival was also analyzed.
Patients and clinical specimens
This study was approved by the Research Ethics Committee of Tianjin Nankai Hospital. Written informed consent was obtained from all of the patients. All specimens were handled and made anonymous according to the ethical and legal standards.
Correlation between miR-198 expression and different clinicopathological features in gastric cancer patients
Low miR-198 expression
High miR-198 expression
36 (48.0 %)
39 (52.0 %)
17 (54.8 %)
14 (45.2 %)
28 (46.7 %)
32 (53.3 %)
25 (54.3 %)
21 (45.7 %)
14 (41.2 %)
20 (58.8 %)
39 (54.2 %)
33 (45.8 %)
29 (43.9 %)
37 (56.1 %)
Diffuse and mixed
24 (60.0 %)
16 (40.0 %)
38 (60.3 %)
25 (39.7 %)
15 (34.9 %)
28 (65.1 %)
16 (34.8 %)
30 (65.2 %)
37 (61.7 %)
23 (38.3 %)
13 (35.1 %)
24 (64.9 %)
40 (58.0 %)
29 (42.0 %)
12 (35.3 %)
22 (64.7 %)
41 (56.9 %)
31 (43.1 %)
RNA extraction and quantitative real-time polymerase chain reaction (PCR)
Total RNA was extracted from clinical specimens by using Trizol reagent (Invitrogen Corp, Carlsbad, CA, USA) according to the manufacturer’s instructions. RNA concentration was measured using a NanoDrop ND-1000 spectrophotometer (Thermo Scientific, Wilmington, DE). Complementary DNA (cDNA) was synthesized from isolated RNA using TaqMan MicroRNA Reverse Transcription Kit and miRNA-specific stem-loop primers (both from Applied Biosystems, Foster City, CA, USA). Real-time PCR was performed with a Taqman MicroRNA Assay Kit (Applied Biosystems) on ABI7500 real-time PCR detection system. Quantitative PCR was conducted at 95 °C for 10 min followed by 40 cycles of 95 °C for 15 s and 60 °C for 60 s. U6 small nuclear RNA was used as an internal control. All reactions were run in triplicates. The cycle threshold (CT) values were recorded, and the relative amount of miR-198 to U6 was calculated using the equation 2−ΔCT, where ΔCT = (CTmiR-198 − CTU6).
All statistical analyses were performed using the SPSS 16.0 software package (SPSS, Chicago, IL, USA). The significance of differences between groups was estimated by Student’s t test and Chi-square test. Survival curves were constructed with the Kaplan-Meier method and compared by log-rank test. The significance of survival variables was evaluated using a multivariate Cox proportional hazards regression analysis. p < 0.05 was considered statistically significant.
Downregulation of miR-198 in human GC tissues
Correlation between miR-198 expression and clinical features of GC
We further analyzed the association between miR-198 expression levels and clinicopathological characteristics of GC. GC samples were classified into low miR-198 expression group (n = 53) and high miR-198 expression group (n = 53) according to the median miR-198 expression level (relative to U6) of all GC samples. The association between clinicopathological characteristics and miR-198 expression was summarized in Table 1. We found that miR-198 level was associated with tumor size (p = 0.009), tumor depth (p = 0.005), lymph node metastasis (p = 0.03), and clinical stage (p = 0.02). However, we did not find any significant correlation between miR-198 levels and other clinicopathological features, such as patient’s gender, age, Lauren type, and cancer differentiation.
Prognostic values of miR-198 expression in GC patients
Univariate and multivariate analysis of overall survival in 106 gastric cancer patients
Identifying novel molecules that take part in GC formation and progression may be helpful for improving the diagnosis, prevention and treatment of this disease. The relationship between miRNAs and tumors has currently become one of the focuses of cancer studies. Abnormal expression of several miRNAs has been reported in GC. For example, miR-1271 was downregulated in GC tissues and correlated with tumor size, lymph node metastasis, and tumor stage . High miR-221 expression and low miR-34a expression are associated with poor prognosis in GC patients [26, 27]. Circulating miR-18a in plasma could discriminate GC patients from healthy controls with a clinically satisfactory degree of sensitivity and specificity . Functional analysis indicated that ectopic miR-874 expression suppressed the growth, migration, invasion, and tumorigenicity of GC cells, whereas miR-874 knockdown promoted these phenotypes . miR-223 and miR-20a could promote cisplatin resistance of GC cells via regulating cell apoptosis [30, 31]. These findings suggested that miRNAs might play important roles in GC initiation and development and have a great potential for clinical application.
In the current study, we found that miR-198 was downregulated in human GC tissues compared with noncancerous tissues. We also found that decreased miR-198 expression was significantly correlated with aggressive clinicopathological features. Moreover, Kaplan-Meier analysis showed that GC patients with low miR-198 expression tend to have shorter overall survival. The multivariate analysis confirmed low miR-198 expression as an independent predictor of poor survival. To the author’s knowledge, this is the first study to analyze the expression and clinical significance of miR-198 in GC.
Previous research has demonstrated the tumor-suppressive functions of miR-198 in several human cancers. Decreased miR-198 expression in colorectal cancer showed a significant association with histological grade, T stage, lymph node invasion, and AJCC stage . Overexpression of miR-198 in colorectal cancer cell lines inhibited cell proliferation, invasion, and migration by targeting fucosyl transferase 8 in vitro. In vivo, restoration of miR-198 significantly inhibited xenograft growth and invasion in nude mice. In pancreatic cancer, reconstitution of miR-198 resulted in reduced tumor growth and metastasis through direct targeting MSLN, PBX-1, and VCP . Low miR-198 levels in pancreatic cancer tissue samples predicted shorter overall survival. In addition, Yang et al. reported that miR-198 inhibited proliferation and induced apoptosis of A549 lung cancer cells via targeting FGFR1 . Tan et al. found that miR-198 inhibited hepatocellular carcinoma cell invasion and migration by targeting the HGF/c-MET pathway . Taken together, these research indicated that loss of miR-198 might contribute to cancer formation and progression. However, the complex molecular mechanisms underlying low miR-198 expression in human cancers and its function are still incompletely known. More studies should be applied to clarify the precise mechanisms by which miR-198 exerts antitumor activity.
In conclusion, our study showed that miR-198 was downregulated in GC tissues and correlated with aggressive clinicopathological features. Furthermore, low miR-198 expression was an important indicator for unfavorable prognosis of GC patients. Due to the limited sample size in our study, further prospective analysis with a large number of tumor samples is worth doing to verify these conclusions.
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- Ferlay J, Shin HR, Bray F, Forman D, Mathers C, Parkin DM. Estimates of worldwide burden of cancer in 2008: GLOBOCAN 2008. Int J Cancer. 2010;127(12):2893–917.View ArticlePubMedGoogle Scholar
- Siewert JR, Sendler A. The current management of gastric cancer. Adv Surg. 1999;33:69–93.PubMedGoogle Scholar
- Duraes C, Almeida GM, Seruca R, Oliveira C, Carneiro F. Biomarkers for gastric cancer: prognostic, predictive or targets of therapy? Virchows Arch. 2014;464(3):367–78.View ArticlePubMedGoogle Scholar
- Fan H, Guo Z, Wang C. Combinations of gene ontology and pathway characterize and predict prognosis genes for recurrence of gastric cancer after surgery. DNA Cell Biol. 2015;34(9):579–87.View ArticlePubMedGoogle Scholar
- Liang L, Fang JY, Xu J: Gastric cancer and gene copy number variation: emerging cancer drivers for targeted therapy. Oncogene 2015. doi:10.1038/onc.2015.209
- Nishida Y, Kuwata T, Nitta H, Dennis E, Aizawa M, Kinoshita T, et al. A novel gene-protein assay for evaluating HER2 status in gastric cancer: simultaneous analyses of HER2 protein overexpression and gene amplification reveal intratumoral heterogeneity. Gastric Cancer. 2015;18(3):458–66.View ArticlePubMedGoogle Scholar
- Bartel DP. MicroRNAs: target recognition and regulatory functions. Cell. 2009;136(2):215–33.View ArticlePubMedPubMed CentralGoogle Scholar
- Esteller M. Non-coding RNAs in human disease. Nat Rev Genet. 2011;12(12):861–74.View ArticlePubMedGoogle Scholar
- Bartel DP. MicroRNAs: genomics, biogenesis, mechanism, and function. Cell. 2004;116(2):281–97.View ArticlePubMedGoogle Scholar
- Cech TR, Steitz JA. The noncoding RNA revolution-trashing old rules to forge new ones. Cell. 2014;157(1):77–94.View ArticlePubMedGoogle Scholar
- Zhang B, Pan X, Cobb GP, Anderson TA. microRNAs as oncogenes and tumor suppressors. Dev Biol. 2007;302(1):1–12.View ArticlePubMedGoogle Scholar
- Dieckmann KP, Spiekermann M, Balks T, Flor I, Loning T, Bullerdiek J, et al. MicroRNAs miR-371-3 in serum as diagnostic tools in the management of testicular germ cell tumours. Br J Cancer. 2012;107(10):1754–60.View ArticlePubMedPubMed CentralGoogle Scholar
- Takahashi M, Cuatrecasas M, Balaguer F, Hur K, Toiyama Y, Castells A, et al. The clinical significance of MiR-148a as a predictive biomarker in patients with advanced colorectal cancer. PLoS One. 2012;7(10):e46684.View ArticlePubMedPubMed CentralGoogle Scholar
- Shi H, Ji Y, Zhang D, Liu Y, Fang P. MiR-135a inhibits migration and invasion and regulates EMT-related marker genes by targeting KLF8 in lung cancer cells. Biochem Biophys Res Commun. 2015;465(1):125–30.View ArticlePubMedGoogle Scholar
- Wu YY, Chen YL, Jao YC, Hsieh IS, Chang KC, Hong TM. miR-320 regulates tumor angiogenesis driven by vascular endothelial cells in oral cancer by silencing neuropilin 1. Angiogenesis. 2014;17(1):247–60.View ArticlePubMedGoogle Scholar
- Yin P, Peng R, Peng H, Yao L, Sun Y, Wen L, et al. MiR-451 suppresses cell proliferation and metastasis in A549 lung cancer cells. Mol Biotechnol. 2015;57(1):1–11.View ArticlePubMedGoogle Scholar
- Yang J, Zhao H, Xin Y, Fan L. MicroRNA-198 inhibits proliferation and induces apoptosis of lung cancer cells via targeting FGFR1. J Cell Biochem. 2014;115(5):987–95.View ArticlePubMedGoogle Scholar
- Wang M, Wang J, Kong X, Chen H, Wang Y, Qin M, et al. MiR-198 represses tumor growth and metastasis in colorectal cancer by targeting fucosyl transferase 8. Sci Rep. 2014;4:6145.View ArticlePubMedGoogle Scholar
- Tan S, Li R, Ding K, Lobie PE, Zhu T. miR-198 inhibits migration and invasion of hepatocellular carcinoma cells by targeting the HGF/c-MET pathway. FEBS Lett. 2011;585(14):2229–34.View ArticlePubMedGoogle Scholar
- Marin-Muller C, Li D, Bharadwaj U, Li M, Chen C, Hodges SE, et al. A tumorigenic factor interactome connected through tumor suppressor microRNA-198 in human pancreatic cancer. Clin Cancer Res. 2013;19(21):5901–13.View ArticlePubMedPubMed CentralGoogle Scholar
- Shen J, DiCioccio R, Odunsi K, Lele SB, Zhao H. Novel genetic variants in miR-191 gene and familial ovarian cancer. BMC Cancer. 2010;10:47.View ArticlePubMedPubMed CentralGoogle Scholar
- Ye L, Li S, Ye D, Yang D, Yue F, Guo Y, et al. Livin expression may be regulated by miR-198 in human prostate cancer cell lines. Eur J Cancer. 2013;49(3):734–40.View ArticlePubMedGoogle Scholar
- Wong TS, Liu XB, Wong BY, Ng RW, Yuen AP, Wei WI. Mature miR-184 as potential oncogenic microRNA of squamous cell carcinoma of tongue. Clin Cancer Res. 2008;14(9):2588–92.View ArticlePubMedGoogle Scholar
- Zhao JJ, Yang J, Lin J, Yao N, Zhu Y, Zheng J, et al. Identification of miRNAs associated with tumorigenesis of retinoblastoma by miRNA microarray analysis. Child’s Nerv Syst. 2009;25(1):13–20.View ArticleGoogle Scholar
- Xiang XJ, Deng J, Liu YW, Wan LY, Feng M, Chen J, et al. MiR-1271 inhibits cell proliferation, invasion and EMT in gastric cancer by targeting FOXQ1. Cell Physiol Biochem. 2015;36(4):1382–94.View ArticlePubMedGoogle Scholar
- Liu K, Li G, Fan C, Diao Y, Wu B, Li J. Increased Expression of MicroRNA-221 in gastric cancer and its clinical significance. J Int Med Res. 2012;40(2):467–74.View ArticlePubMedGoogle Scholar
- Zhang H, Li S, Yang J, Liu S, Gong X, Yu X. The prognostic value of miR-34a expression in completely resected gastric cancer: tumor recurrence and overall survival. Int J Clin Exp Med. 2015;8(2):2635–41.PubMedPubMed CentralGoogle Scholar
- Tsujiura M, Komatsu S, Ichikawa D, Shiozaki A, Konishi H, Takeshita H, et al. Circulating miR-18a in plasma contributes to cancer detection and monitoring in patients with gastric cancer. Gastric Cancer. 2015;18(2):271–9.View ArticlePubMedGoogle Scholar
- Jiang B, Li Z, Zhang W, Wang H, Zhi X, Feng J, et al. miR-874 Inhibits cell proliferation, migration and invasion through targeting aquaporin-3 in gastric cancer. J Gastroenterol. 2014;49(6):1011–25.View ArticlePubMedGoogle Scholar
- Zhou X, Jin W, Jia H, Yan J, Zhang G. MiR-223 promotes the cisplatin resistance of human gastric cancer cells via regulating cell cycle by targeting FBXW7. J Exp Clin Cancer Res. 2015;34:28.View ArticlePubMedPubMed CentralGoogle Scholar
- Du Y, Zhu M, Zhou X, Huang Z, Zhu J, Xu J, Cheng G, Shu Y, Liu P, Zhu W et al: miR-20a enhances cisplatin resistance of human gastric cancer cell line by targeting NFKBIB. Tumour Biol 2015.Google Scholar