0115 966 7955 Today's Opening Times 10:30 - 17:00 (BST)
Banner ad for Viper plagiarism checker

Levels of miRNAs, miR-194, 29b Markers for Colorectal Cancer

Published: Last Edited:

Disclaimer: This essay has been submitted by a student. This is not an example of the work written by our professional essay writers. You can view samples of our professional work here.

Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of UK Essays.

Circulating levels of the miRNAs, miR-194 and 29b, as clinically useful biomarkers for colorectal cancer

Colorectal cancer (CRC) has been reported as the fourth common cause of cancer mortality around the world with considerable health burden (1). Early stage diagnosis of the disease by noninvasive approaches could lead to effective treatment and better consequences (2). In this regard, microRNAs (miRNAs) in a few biological samples may deserve as early detection biomarkers for CRC (2, 3). miRNAs are endogenous small, non-protein coding RNAs that posttranscriptionally regulate expression of a broad range of biologically important genes function as either oncogenes or tumor suppressor genes depending on their physiopathological contribution and the tumour microenvironment (3, 4). Given the contribution of miRNAs in the pathogenesis of tumor cells, dysregulation of some miRNAs in tumor tissue would be conceivable. In fact, altered expression of a variety of miRNAs has been corroborated in CRC tissues (3).

Alteration in the expression of miRNAs in cancerous tissue may also be reflected in circulation (5). Therefore, altered levels of some miRNAs in plasma/serum or other body fluids of CRC patients have been extensively explored in an effort to find suitable diagnostic and prognostic biomarkers (6). In this regard, the miRNAs, miR-194 and miR-29b, may act as circulating invaluable and surrogate biomarkers for CRC. While miR-194 has been shown to be upregulated in oesophageal squamous cell carcinoma (7) and prostate cancer (8), its downregulation has been recently reported in endometrial cancer (9), primary renal cell carcinoma (10), and CRC tissues (11, 12). Notably, low expression level of miR-194 in CRC tissues was shown to be correlated with increased tumor size (11, 12). Furthermore, the decreased level of miR-194 in stool samples was indicated to differentiate CRC patients from normal subjects (12). On the other hand, miR-29b suppresses proliferation of epithelial cells of intestinal mucosa (13), inhibits migration of colon cancer cells (14) and is significantly downregulated in osteosarcoma tissues (15). Given the involvement of miR-194 and miR-29b in some cancers including CRC and that there were no studies regarding their circulating levels in CRC, we determined the serum levels of miR-194 and miR-29b in a relatively large number of CRC patients, relative to control subjects, by real-time PCR assay to explore their diagnostic and prognostic values.

Materials and methods

Serum samples of 40 patients with colorectal adenocarcinoma and 40 control subjects were obtained at the Cancer Institute of Tehran, Iran. The obtained serum samples were further centrifugated in conical tubes for 10 min at 16000 g and 4°C in a fixed-angle rotor centrifuge and the new supernatants were immediately preserved at -80°C in multiple aliquots until further analysis. Diagnosis of patients and control subjects were based on colonoscopy and histopathological findings. None of the subjects under study had undergone any medical intervention such as radiotherapy, chemotherapy and surgery before sampling. All CRC patients underwent tumour resection and their clinical stages were determined according to the tumor-node-metastasis (TNM) staging system. Exclusion criteria included chronic or acute inflammatory conditions and any other malignancies except CRC.

The study was approved by the Ethics Committee of the Institute and all patients and control subjects provided written informed consents before enrollment in the study.

Serum RNA Extraction

For RNA isolation the frozen serum samples were thawed thoroughly on ice. Total RNA was isolated from 200 µl of serum using the miRNeasy Serum/Plasma Kit (Qiagen, CA, USA) following the manufacturer’s instructions, with minor modifications. For the aqueous and organic phase separation step, 200 µL of molecular grade chloroform was added to the mixture of Qiazol solution (denaturant reagent of the kit) and serum and vortexed vigorously for 30 s, followed by incubation at room temperature for 5 min. The serum samples, after denaturation by the denaturant reagent, were spiked with 5 μL of 25 fmol synthetic cel-miR-39 (Invitrogen, CA, USA) as control. At final, total RNA was eluted from the spin column membrane by elution with 30 μL RNase-free and about 28 μL of total RNA solution was eluted. Optical density of the extracted total RNA samples were assessed at the wavelengths 260 and 280 nm on a NanoDrop spectrophotometer (NanoDrop, Wilmington, DE, USA) to determine their concentrations and purities. The isolated total RNA samples were preserved at -80°C until subsequent analysis.

Quantitative real-time PCR

The reverse transcription reaction was performed using a miScript II Reverse Transcription Kit (Qiagen, CA, USA) according to the manufacturer’s protocol.

The reverse transcription reaction was carried out using a Taqman MicroRNA Reverse Transcription Kit (Applied Biosystems).

References

  1. Global cancer statistics, 2002. CA Cancer J Clin. 2005 Mar-Apr;55(2):74-108.
  2. Vilvapathy Narayanan, Maikel P. Peppelenbosch, and Sergey R. Konstantinov. Human Fecal Microbiome–Based Biomarkers for Colorectal Cancer. Cancer Prev Res November 2014 7:1108-1111. doi:10.1158/1940-6207.CAPR-14-0273
  3. Aaron J. Schetter, Hirokazu Okayama, and Curtis C. Harris. The Role of microRNAs in Colorectal Cancer. Cancer J. 2012 May ; 18(3): 244–252. doi:10.1097/PPO.0b013e318258b78f.
  4. Bartel, D.P. MicroRNAs: Target recognition and regulatory functions. Cell 2009, 136, 215–233.
  5. Mitchell PS1, Parkin RK, Kroh EM, Fritz BR, Wyman SK, Pogosova-Agadjanyan EL, et al. Circulating microRNAs as stable blood-based markers for cancer detection. Proc Natl Acad Sci U S A. 2008 Jul 29;105(30):10513-8.
  6. Moisés Blanco-Calvo, Lourdes Calvo, Angélica Figueroa, Mar Haz-Conde et al. Circulating MicroRNAs: Molecular Microsensors in Gastrointestinal Cancer Sensors 2012, 12, 9349-9362; doi:10.3390/s120709349
  7. Haiyan Zhai1, Mihriban Karaayvaz1, Peixin Dong2, Noriaki Sakuragi2 and Jingfang Ju. Prognostic significance of miR-194 in endometrial cancer. Biomarker Research 2013, 1:12
  8. L A Selth, S L Townley, A G Bert, P D Stricker, P D Sutherland, L G Horvath, et al. Circulating microRNAs predict biochemical recurrence in prostate cancer patients. British Journal of Cancer (2013) 109, 641–650 | doi: 10.1038/bjc.2013.369.
  9. Haiyan Zhai1, Mihriban Karaayvaz1, Peixin Dong2, Noriaki Sakuragi2 and Jingfang Ju. Prognostic significance of miR-194 in endometrial cancer. Biomarker Research 2013, 1:12
  10. White,N.M. et al. (2011) miRNA profiling for clear cell renal cell carcinoma: biomarker discovery and identification of potential controls and consequences of miRNA dysregulation. J. Urol., 186, 1077–1083.
  11. Chiang Y, Song Y, Wang Z, Liu Z, Gao P, Liang J, et al. microRNA-192, -194 and -215 are frequently downregulated in colorectal cancer. Exp Ther Med. 2012; 3: 560-6. doi:10.3892/etm.2011.436.
  12. Hui-Jun Zhao 1*, Lin-Lin Ren 1*, Zhen-Hua Wang1*, Tian-Tian Sun1, Ya-Nan Yu1, et al. MiR-194 Deregulation Contributes To Colorectal Carcinogenesis via Targeting AKT2 Pathway. Theranostics 2014; 4(12): 1193-1208. doi: 10.7150/thno.8712.
  13. Lan Xiaoa,b, Jaladanki N. Raoa,b, Tongtong Zoua,b, Lan Liua,b, Shan Caoa, et al. miR-29b represses intestinal mucosal growth by inhibiting translation of cyclin-dependent kinase 2. Molecular Biology of the Cell. doi/10.1091/mbc.E13-05-0287)
  14. Deepak Poudyal1, Xiangli Cui1,2, Phuong Mai Le3, Anne B. Hofseth1, Anthony Windust3, et al. A Key Role of microRNA-29b for the Suppression of Colon Cancer Cell Migration by American Ginseng. PLoS ONE 8(10): e75034. doi:10.1371/journal.pone.0075034.
  15. Kexiang Zhang, Chaoyue Zhang, Li Liu, Jiahui Zhou. A key role of microRNA-29b in suppression of osteosarcoma cell proliferation and migration via modulation of VEGF. Int J Clin Exp Pathol 2014;7(9):5701-5708

To export a reference to this article please select a referencing stye below:

Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.

Request Removal

If you are the original writer of this essay and no longer wish to have the essay published on the UK Essays website then please click on the link below to request removal:


More from UK Essays

We can help with your essay
Find out more