MicroRNA Expression and Correlation with mRNA Levels of Colorectal Cancer-Related Genes
MicroRNAs (miRNAs), as a family of non-coding RNAs, have opened a new window in cancer biology and transcriptome. It has been revealed that miRNAs post-transcriptionally regulate the gene expression and involve in colorectal cancer (CRC) development and progression. Our aim was to examine the differential expression of miRNAs in a CRC and to correlate their expression levels with mRNA levels of CRC-related genes (K-ras, APC, p53).
Materials and Methods
Seventy-two colorectal tumor tissues from patients with newly diagnosed CRC and 72 matched normal adjacent tissues were analyzed. Relative expression of seven CRC-related miRNAs (miR-21, miR-31, miR-20a, miR-133b, and miR-145, miR-135b and let-7g) and three CRC-related genes (K-ras, APC, p53) was detected using the SYBR Green quantitative real-time PCR technique. The correlation between gene expression levels and clinicopathological features was evaluated.
Our results showed a significant difference between the two groups for the expression level of miR-21, miR-31, miR-145, and miR-20a (P < 0.001). Also, a significant difference between the two groups for the expression level of K-ras was found (P < 0.001). Further analysis revealed an inverse significant correlation between miR-145 and K-ras (R2 = 0.662, P < 0.001), while a positive correlation was observed between miR-21 and K-ras (R2 = 0.732, P < 0.001).
Dysregulation of miRNAs and correlation with molecular signaling pathways designated a biological role for miRNAs in various cellular mechanisms underlying CRC. On the other hand, the pattern of miRNAs expression and its correlation with transcriptional status are helpful to discovery biomarkers and design therapeutics for CRC.
KeywordsColorectal cancer Correlation Gene expression K-ras MicroRNA
We would like to thank the patients who participated in the study.
PG and AA contributed to the study design and conception. FM and SM performed experiments. AA and AT assisted with the analysis of the data. AA prepared the manuscript which PG and AT significantly revised. All authors read and approved the final manuscript.
This work was financially supported by Deputy of Research, Iran University of Medical Sciences (Grant No. 26699).
Compliance with Ethical Standards
The project was approved by the Research Ethics Committee (Ethical code number: IR.IUMS.REC 94–26699.) All patients signed a free and informed consent form for enrollment in the study.
Conflict of Interest
All authors declare that they have no competing interests.
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