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Review
. 2021 Feb 12;14(2):149.
doi: 10.3390/ph14020149.

The Role of miRNA-7 in the Biology of Cancer and Modulation of Drug Resistance

Ewa Gajda  1 , Małgorzata Grzanka  1 , Marlena Godlewska  1 , Damian Gawel  2
Affiliations
Review

The Role of miRNA-7 in the Biology of Cancer and Modulation of Drug Resistance

Ewa Gajda et al. Pharmaceuticals (Basel). .

Abstract

MicroRNAs (miRNAs, miRs) are small non-coding RNA (ncRNA) molecules capable of regulating post-transcriptional gene expression. Imbalances in the miRNA network have been associated with the development of many pathological conditions and diseases, including cancer. Recently, miRNAs have also been linked to the phenomenon of multidrug resistance (MDR). MiR-7 is one of the extensively studied miRNAs and its role in cancer progression and MDR modulation has been highlighted. MiR-7 is engaged in multiple cellular pathways and acts as a tumor suppressor in the majority of human neoplasia. Its depletion limits the effectiveness of anti-cancer therapies, while its restoration sensitizes cells to the administered drugs. Therefore, miR-7 might be considered as a potential adjuvant agent, which can increase the efficiency of standard chemotherapeutics.

Keywords: cancer; miR-7; multidrug resistance.

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Conflict of interest statement

All Authors declare no conflict of interest.

Figures

Figure 1
Figure 1
A graphical representation of the canonical pathway of miRNA biogenesis in animals. The MIR gene encodes pri-miRNA. Modification of the pri-miRNA hairpin with two free ends takes place in the cell nucleus. The DGCR8 (DiGeorge critical region 8) and Drosha enzymes cut off the free strands from the hairpin giving pre-miRNA. Then, pre-miRNA is transported into the cytoplasm by Exportin 5 (Exp5), where the Dicer and TRBP (TAR double-stranded RNA binding protein) complex removes the hairpin’s loop and cleaves the molecule into the miRNA duplex. One of the duplex strands, along with the RNA-induced silencing complex (RISC), is involved in mRNA targeting. The second one is degraded.
Figure 2
Figure 2
Biogenesis of miR-7. (A) miR-7 is the result of transcription of the MIR7-1, MIR7-2, and MIR7-3 genes located on chromosomes 9, 15, and 19, respectively. The generated pri-miRs are transformed into pre-miR-7. Exp5 transports them through the nuclear pores to the cytoplasm (B), where pre-miR-7-1, pre-miR-7-2, and pre-miR-7-3 (C) undergo further modifications. The Dicer complex, cleaves double-stranded RNA (dsRNA) into shorter nucleotide duplexes. Sequences marked in pink are involved in the regulation of mRNA expression.
Figure 3
Figure 3
Tumor-related signaling pathways and proteins associated with depletion of miR-7.
See this image and copyright information in PMC

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