MiR-125b Inhibits Cell Proliferation and Induces Apoptosis in Human Colon Cancer SW480 Cells via Targeting STAT3

Investigation of the potential of miRNA candidates as non-invasive biomarkers for the diagnosis and follow-up of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer worldwide, and despite advances in treatment, molecular biomarkers are needed for both early diagnosis and prognosis monitoring. It is known that microRNAs (miRNA), one of the epigenetic mechanisms, are effective in the initiation and development of cancer by regulating the activity of tumor suppressors and/or oncogenes. In this study, the potential of the molecules let-7, miRNA125b, and miRNA30a, which are known to play a role in cellular processes, as biomarkers for colorectal cancer and their molecular mechanisms were investigated in this model. The aim was to evaluate the diagnostic, prognostic, and predictive utility of the target miRNAs in colorectal cancer patients.

MATERIAL AND METHODS

The expression changes of miRNAs let-7, miRNA125b, and miRNA30a were investigated by miRNAs isolation and cDNA synthesis from the serum samples of 60 patients diagnosed with CRC or from the serum samples of 20 healthy individuals. The calculation was performed using the quantitative real-time polymerase chain reaction method to determine the expression level. The results were compared with clinical parameters.

RESULT

An 8-fold decrease in the expression of let-7 and miRNA125b and a 60-fold decrease in the expression of miRNA30a were found in the serum samples of patients diagnosed with colorectal cancer (CRC) compared to the healthy group. A decrease in let-7 was observed in 53.3%, miRNA125b in 58.3%, and miRNA30a in 55% of patients. A significant correlation was found between the reduced expression status and the stage, lymph nodes, local recurrence, and metastasis (p < 0.05). The ROC analysis showed that the miRNA30a level could be a diagnostic biomarker for CRC (p < 0.001). No significant impact of target miRNA expression changes on overall disease survival was observed.

CONCLUSION

It is thought that the target miRNA30a can be used for early diagnosis and screening and that the target miRNA let-7, miRNA125b, and miRNA30a can be used as non-invasive biomarkers for disease follow-up, with larger patient studies being conducted on CRC patients.

Different Roles of Apoptosis and Autophagy in the Development of Human Colorectal Cancer

Colorectal cancer (CRC) remains a major life-threatening malignancy, despite numerous therapeutic and screening attempts. Apoptosis and autophagy are two processes that share common signaling pathways, are linked by functional relationships and have similar protein components. During the development of cancer, the two processes can trigger simultaneously in the same cell, causing, in some cases, an inhibition of autophagy by apoptosis or apoptosis by autophagy. Malignant cells that have accumulated genetic alterations can take advantage of any alterations in the apoptotic process and as a result, progress easily in the cancerous transformation. Autophagy often plays a suppressive role during the initial stages of carcinogenicity, while in the later stages of cancer development it can play a promoting role. It is extremely important to determine the regulation of this duality of autophagy in the development of CRC and to identify the molecules involved, as well as the signals and the mechanisms behind it. All the reported experimental results indicate that, while the antagonistic effects of autophagy and apoptosis occur in an adverse environment characterized by deprivation of oxygen and nutrients, leading to the formation and development of CRC, the effects of promotion and collaboration usually involve an auxiliary role of autophagy compared to apoptosis. In this review, we elucidate the different roles of autophagy and apoptosis in human CRC development.

Flavonoids Inhibit Cancer by Regulating the Competing Endogenous RNA Network

Flavonoids are present in a wide range of plants. They have been used in the treatment of cancer, but the mechanism underlying this activity is unclear. In recent years, microRNA (miRNA) and long non-coding RNA (lncRNA) levels have been observed to differ between normal tissues and cancer cells, and both types of RNA have been shown to have a role in tumor treatment. In addition, flavonoids have been proven to regulate miRNAs and LncRNAs in the treatment of cancer. The competing endogenous RNA (ceRNA) network is a complex post-transcriptional regulatory mechanism in cells, in which coding and non-coding RNAs competitively bind miRNAs to regulate messenger RNAs (mRNAs). This review focused on the role of the ceRNA network in the treatment of cancer by flavonoids.